€•J      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ&/translations/zh_CN/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/zh_TW/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/it_IT/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/ja_JP/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/ko_KR/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒPortuguese (Brazilian)”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/pt_BR/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh–sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ&/translations/sp_SP/security/keys/core”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒKernel Key Retention Service”h]”hŒKernel Key Retention Service”…””}”(hh¼h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hºhh·h²hh³Œ@/var/lib/git/docbuild/linux/Documentation/security/keys/core.rst”h´KubhŒ	paragraph”“”)”}”(hŒ·This service allows cryptographic keys, authentication tokens, cross-domain
user mappings, and similar to be cached in the kernel for the use of
filesystems and other kernel services.”h]”hŒ·This service allows cryptographic keys, authentication tokens, cross-domain
user mappings, and similar to be cached in the kernel for the use of
filesystems and other kernel services.”…””}”(hhÍh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khh·h²hubhÌ)”}”(hŒÇKeyrings are permitted; these are a special type of key that can hold links to
other keys. Processes each have three standard keyring subscriptions that a
kernel service can search for relevant keys.”h]”hŒÇKeyrings are permitted; these are a special type of key that can hold links to
other keys. Processes each have three standard keyring subscriptions that a
kernel service can search for relevant keys.”…””}”(hhÛh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K	hh·h²hubhÌ)”}”(hŒ1The key service can be configured on by enabling:”h]”hŒ1The key service can be configured on by enabling:”…””}”(hhéh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khh·h²hubhŒblock_quote”“”)”}”(hŒG"Security options"/"Enable access key retention support" (CONFIG_KEYS)
”h]”hÌ)”}”(hŒF"Security options"/"Enable access key retention support" (CONFIG_KEYS)”h]”hŒNâ€œSecurity optionsâ€/â€Enable access key retention supportâ€ (CONFIG_KEYS)”…””}”(hhýh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khhùubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Khh·h²hubhÌ)”}”(hŒ)This document has the following sections:”h]”hŒ)This document has the following sections:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khh·h²hubhŒtopic”“”)”}”(hhh]”hŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hhh]”hÌ)”}”(hhh]”hŒ	reference”“”)”}”(hhh]”hŒKey Overview”…””}”(hj3  h²hh³Nh´Nubah}”(h]”Œid1”ah ]”h"]”h$]”h&]”Œrefid”Œkey-overview”uh1j1  hj.  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj+  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒKey Service Overview”…””}”(hjU  h²hh³Nh´Nubah}”(h]”Œid2”ah ]”h"]”h$]”h&]”Œrefid”Œkey-service-overview”uh1j1  hjR  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhjO  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒKey Access Permissions”…””}”(hjw  h²hh³Nh´Nubah}”(h]”Œid3”ah ]”h"]”h$]”h&]”Œrefid”Œkey-access-permissions”uh1j1  hjt  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhjq  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒSELinux Support”…””}”(hj™  h²hh³Nh´Nubah}”(h]”Œid4”ah ]”h"]”h$]”h&]”Œrefid”Œselinux-support”uh1j1  hj–  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj“  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒNew ProcFS Files”…””}”(hj»  h²hh³Nh´Nubah}”(h]”Œid5”ah ]”h"]”h$]”h&]”Œrefid”Œnew-procfs-files”uh1j1  hj¸  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhjµ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒUserspace System Call Interface”…””}”(hjÝ  h²hh³Nh´Nubah}”(h]”Œid6”ah ]”h"]”h$]”h&]”Œrefid”Œuserspace-system-call-interface”uh1j1  hjÚ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj×  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒKernel Services”…””}”(hjÿ  h²hh³Nh´Nubah}”(h]”Œid7”ah ]”h"]”h$]”h&]”Œrefid”Œkernel-services”uh1j1  hjü  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhjù  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒ#Notes On Accessing Payload Contents”…””}”(hj!  h²hh³Nh´Nubah}”(h]”Œid8”ah ]”h"]”h$]”h&]”Œrefid”Œ#notes-on-accessing-payload-contents”uh1j1  hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒDefining a Key Type”…””}”(hjC  h²hh³Nh´Nubah}”(h]”Œid9”ah ]”h"]”h$]”h&]”Œrefid”Œdefining-a-key-type”uh1j1  hj@  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj=  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒRequest-Key Callback Service”…””}”(hje  h²hh³Nh´Nubah}”(h]”Œid10”ah ]”h"]”h$]”h&]”Œrefid”Œrequest-key-callback-service”uh1j1  hjb  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj_  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubj*  )”}”(hhh]”hÌ)”}”(hhh]”j2  )”}”(hhh]”hŒGarbage Collection”…””}”(hj‡  h²hh³Nh´Nubah}”(h]”Œid11”ah ]”h"]”h$]”h&]”Œrefid”Œgarbage-collection”uh1j1  hj„  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËhj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj&  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j$  hj!  h²hh³Nh´Nubah}”(h]”Œcontents”ah ]”(Œcontents”Œlocal”eh"]”Œcontents”ah$]”h&]”uh1j  h³hÊh´Khh·h²hubh¶)”}”(hhh]”(h»)”}”(hŒKey Overview”h]”hŒKey Overview”…””}”(hj¶  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefid”j<  uh1hºhj³  h²hh³hÊh´KubhÌ)”}”(hŒ–In this context, keys represent units of cryptographic data, authentication
tokens, keyrings, etc.. These are represented in the kernel by struct key.”h]”hŒ–In this context, keys represent units of cryptographic data, authentication
tokens, keyrings, etc.. These are represented in the kernel by struct key.”…””}”(hjÅ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khj³  h²hubhÌ)”}”(hŒ$Each key has a number of attributes:”h]”hŒ$Each key has a number of attributes:”…””}”(hjÓ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khj³  h²hubhø)”}”(hX;        - A serial number.
      - A type.
      - A description (for matching a key in a search).
      - Access control information.
      - An expiry time.
      - A payload.
      - State.


*  Each key is issued a serial number of type key_serial_t that is unique for
   the lifetime of that key. All serial numbers are positive non-zero 32-bit
   integers.

   Userspace programs can use a key's serial numbers as a way to gain access
   to it, subject to permission checking.

*  Each key is of a defined "type". Types must be registered inside the
   kernel by a kernel service (such as a filesystem) before keys of that type
   can be added or used. Userspace programs cannot define new types directly.

   Key types are represented in the kernel by struct key_type. This defines a
   number of operations that can be performed on a key of that type.

   Should a type be removed from the system, all the keys of that type will
   be invalidated.

*  Each key has a description. This should be a printable string. The key
   type provides an operation to perform a match between the description on a
   key and a criterion string.

*  Each key has an owner user ID, a group ID and a permissions mask. These
   are used to control what a process may do to a key from userspace, and
   whether a kernel service will be able to find the key.

*  Each key can be set to expire at a specific time by the key type's
   instantiation function. Keys can also be immortal.

*  Each key can have a payload. This is a quantity of data that represent the
   actual "key". In the case of a keyring, this is a list of keys to which
   the keyring links; in the case of a user-defined key, it's an arbitrary
   blob of data.

   Having a payload is not required; and the payload can, in fact, just be a
   value stored in the struct key itself.

   When a key is instantiated, the key type's instantiation function is
   called with a blob of data, and that then creates the key's payload in
   some way.

   Similarly, when userspace wants to read back the contents of the key, if
   permitted, another key type operation will be called to convert the key's
   attached payload back into a blob of data.

*  Each key can be in one of a number of basic states:

    *  Uninstantiated. The key exists, but does not have any data attached.
       Keys being requested from userspace will be in this state.

    *  Instantiated. This is the normal state. The key is fully formed, and
       has data attached.

    *  Negative. This is a relatively short-lived state. The key acts as a
       note saying that a previous call out to userspace failed, and acts as
       a throttle on key lookups. A negative key can be updated to a normal
       state.

    *  Expired. Keys can have lifetimes set. If their lifetime is exceeded,
       they traverse to this state. An expired key can be updated back to a
       normal state.

    *  Revoked. A key is put in this state by userspace action. It can't be
       found or operated upon (apart from by unlinking it).

    *  Dead. The key's type was unregistered, and so the key is now useless.
”h]”(hø)”}”(hŒ–- A serial number.
- A type.
- A description (for matching a key in a search).
- Access control information.
- An expiry time.
- A payload.
- State.

”h]”j%  )”}”(hhh]”(j*  )”}”(hŒA serial number.”h]”hÌ)”}”(hjî  h]”hŒA serial number.”…””}”(hjð  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khjì  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubj*  )”}”(hŒA type.”h]”hÌ)”}”(hj  h]”hŒA type.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubj*  )”}”(hŒ/A description (for matching a key in a search).”h]”hÌ)”}”(hj  h]”hŒ/A description (for matching a key in a search).”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubj*  )”}”(hŒAccess control information.”h]”hÌ)”}”(hj3  h]”hŒAccess control information.”…””}”(hj5  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K!hj1  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubj*  )”}”(hŒAn expiry time.”h]”hÌ)”}”(hjJ  h]”hŒAn expiry time.”…””}”(hjL  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K"hjH  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubj*  )”}”(hŒ
A payload.”h]”hÌ)”}”(hja  h]”hŒ
A payload.”…””}”(hjc  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K#hj_  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubj*  )”}”(hŒState.

”h]”hÌ)”}”(hŒState.”h]”hŒState.”…””}”(hjz  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K$hjv  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjé  ubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1j$  h³hÊh´Khjå  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Khjá  ubj%  )”}”(hhh]”(j*  )”}”(hX  Each key is issued a serial number of type key_serial_t that is unique for
the lifetime of that key. All serial numbers are positive non-zero 32-bit
integers.

Userspace programs can use a key's serial numbers as a way to gain access
to it, subject to permission checking.
”h]”(hÌ)”}”(hŒžEach key is issued a serial number of type key_serial_t that is unique for
the lifetime of that key. All serial numbers are positive non-zero 32-bit
integers.”h]”hŒžEach key is issued a serial number of type key_serial_t that is unique for
the lifetime of that key. All serial numbers are positive non-zero 32-bit
integers.”…””}”(hj£  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K'hjŸ  ubhÌ)”}”(hŒpUserspace programs can use a key's serial numbers as a way to gain access
to it, subject to permission checking.”h]”hŒrUserspace programs can use a keyâ€™s serial numbers as a way to gain access
to it, subject to permission checking.”…””}”(hj±  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K+hjŸ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubj*  )”}”(hXÃ  Each key is of a defined "type". Types must be registered inside the
kernel by a kernel service (such as a filesystem) before keys of that type
can be added or used. Userspace programs cannot define new types directly.

Key types are represented in the kernel by struct key_type. This defines a
number of operations that can be performed on a key of that type.

Should a type be removed from the system, all the keys of that type will
be invalidated.
”h]”(hÌ)”}”(hŒÚEach key is of a defined "type". Types must be registered inside the
kernel by a kernel service (such as a filesystem) before keys of that type
can be added or used. Userspace programs cannot define new types directly.”h]”hŒÞEach key is of a defined â€œtypeâ€. Types must be registered inside the
kernel by a kernel service (such as a filesystem) before keys of that type
can be added or used. Userspace programs cannot define new types directly.”…””}”(hjÉ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K.hjÅ  ubhÌ)”}”(hŒŒKey types are represented in the kernel by struct key_type. This defines a
number of operations that can be performed on a key of that type.”h]”hŒŒKey types are represented in the kernel by struct key_type. This defines a
number of operations that can be performed on a key of that type.”…””}”(hj×  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K2hjÅ  ubhÌ)”}”(hŒXShould a type be removed from the system, all the keys of that type will
be invalidated.”h]”hŒXShould a type be removed from the system, all the keys of that type will
be invalidated.”…””}”(hjå  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K5hjÅ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubj*  )”}”(hŒ®Each key has a description. This should be a printable string. The key
type provides an operation to perform a match between the description on a
key and a criterion string.
”h]”hÌ)”}”(hŒ­Each key has a description. This should be a printable string. The key
type provides an operation to perform a match between the description on a
key and a criterion string.”h]”hŒ­Each key has a description. This should be a printable string. The key
type provides an operation to perform a match between the description on a
key and a criterion string.”…””}”(hjý  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K8hjù  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubj*  )”}”(hŒÆEach key has an owner user ID, a group ID and a permissions mask. These
are used to control what a process may do to a key from userspace, and
whether a kernel service will be able to find the key.
”h]”hÌ)”}”(hŒÅEach key has an owner user ID, a group ID and a permissions mask. These
are used to control what a process may do to a key from userspace, and
whether a kernel service will be able to find the key.”h]”hŒÅEach key has an owner user ID, a group ID and a permissions mask. These
are used to control what a process may do to a key from userspace, and
whether a kernel service will be able to find the key.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K<hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubj*  )”}”(hŒvEach key can be set to expire at a specific time by the key type's
instantiation function. Keys can also be immortal.
”h]”hÌ)”}”(hŒuEach key can be set to expire at a specific time by the key type's
instantiation function. Keys can also be immortal.”h]”hŒwEach key can be set to expire at a specific time by the key typeâ€™s
instantiation function. Keys can also be immortal.”…””}”(hj-  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K@hj)  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubj*  )”}”(hX±  Each key can have a payload. This is a quantity of data that represent the
actual "key". In the case of a keyring, this is a list of keys to which
the keyring links; in the case of a user-defined key, it's an arbitrary
blob of data.

Having a payload is not required; and the payload can, in fact, just be a
value stored in the struct key itself.

When a key is instantiated, the key type's instantiation function is
called with a blob of data, and that then creates the key's payload in
some way.

Similarly, when userspace wants to read back the contents of the key, if
permitted, another key type operation will be called to convert the key's
attached payload back into a blob of data.
”h]”(hÌ)”}”(hŒèEach key can have a payload. This is a quantity of data that represent the
actual "key". In the case of a keyring, this is a list of keys to which
the keyring links; in the case of a user-defined key, it's an arbitrary
blob of data.”h]”hŒîEach key can have a payload. This is a quantity of data that represent the
actual â€œkeyâ€. In the case of a keyring, this is a list of keys to which
the keyring links; in the case of a user-defined key, itâ€™s an arbitrary
blob of data.”…””}”(hjE  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KChjA  ubhÌ)”}”(hŒpHaving a payload is not required; and the payload can, in fact, just be a
value stored in the struct key itself.”h]”hŒpHaving a payload is not required; and the payload can, in fact, just be a
value stored in the struct key itself.”…””}”(hjS  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KHhjA  ubhÌ)”}”(hŒ•When a key is instantiated, the key type's instantiation function is
called with a blob of data, and that then creates the key's payload in
some way.”h]”hŒ™When a key is instantiated, the key typeâ€™s instantiation function is
called with a blob of data, and that then creates the keyâ€™s payload in
some way.”…””}”(hja  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KKhjA  ubhÌ)”}”(hŒ½Similarly, when userspace wants to read back the contents of the key, if
permitted, another key type operation will be called to convert the key's
attached payload back into a blob of data.”h]”hŒ¿Similarly, when userspace wants to read back the contents of the key, if
permitted, another key type operation will be called to convert the keyâ€™s
attached payload back into a blob of data.”…””}”(hjo  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KOhjA  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubj*  )”}”(hXx  Each key can be in one of a number of basic states:

 *  Uninstantiated. The key exists, but does not have any data attached.
    Keys being requested from userspace will be in this state.

 *  Instantiated. This is the normal state. The key is fully formed, and
    has data attached.

 *  Negative. This is a relatively short-lived state. The key acts as a
    note saying that a previous call out to userspace failed, and acts as
    a throttle on key lookups. A negative key can be updated to a normal
    state.

 *  Expired. Keys can have lifetimes set. If their lifetime is exceeded,
    they traverse to this state. An expired key can be updated back to a
    normal state.

 *  Revoked. A key is put in this state by userspace action. It can't be
    found or operated upon (apart from by unlinking it).

 *  Dead. The key's type was unregistered, and so the key is now useless.
”h]”(hÌ)”}”(hŒ3Each key can be in one of a number of basic states:”h]”hŒ3Each key can be in one of a number of basic states:”…””}”(hj‡  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KShjƒ  ubhø)”}”(hX5  *  Uninstantiated. The key exists, but does not have any data attached.
   Keys being requested from userspace will be in this state.

*  Instantiated. This is the normal state. The key is fully formed, and
   has data attached.

*  Negative. This is a relatively short-lived state. The key acts as a
   note saying that a previous call out to userspace failed, and acts as
   a throttle on key lookups. A negative key can be updated to a normal
   state.

*  Expired. Keys can have lifetimes set. If their lifetime is exceeded,
   they traverse to this state. An expired key can be updated back to a
   normal state.

*  Revoked. A key is put in this state by userspace action. It can't be
   found or operated upon (apart from by unlinking it).

*  Dead. The key's type was unregistered, and so the key is now useless.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒ€Uninstantiated. The key exists, but does not have any data attached.
Keys being requested from userspace will be in this state.
”h]”hÌ)”}”(hŒUninstantiated. The key exists, but does not have any data attached.
Keys being requested from userspace will be in this state.”h]”hŒUninstantiated. The key exists, but does not have any data attached.
Keys being requested from userspace will be in this state.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KUhjœ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj™  ubj*  )”}”(hŒXInstantiated. This is the normal state. The key is fully formed, and
has data attached.
”h]”hÌ)”}”(hŒWInstantiated. This is the normal state. The key is fully formed, and
has data attached.”h]”hŒWInstantiated. This is the normal state. The key is fully formed, and
has data attached.”…””}”(hj¸  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KXhj´  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj™  ubj*  )”}”(hŒÖNegative. This is a relatively short-lived state. The key acts as a
note saying that a previous call out to userspace failed, and acts as
a throttle on key lookups. A negative key can be updated to a normal
state.
”h]”hÌ)”}”(hŒÕNegative. This is a relatively short-lived state. The key acts as a
note saying that a previous call out to userspace failed, and acts as
a throttle on key lookups. A negative key can be updated to a normal
state.”h]”hŒÕNegative. This is a relatively short-lived state. The key acts as a
note saying that a previous call out to userspace failed, and acts as
a throttle on key lookups. A negative key can be updated to a normal
state.”…””}”(hjÐ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K[hjÌ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj™  ubj*  )”}”(hŒ˜Expired. Keys can have lifetimes set. If their lifetime is exceeded,
they traverse to this state. An expired key can be updated back to a
normal state.
”h]”hÌ)”}”(hŒ—Expired. Keys can have lifetimes set. If their lifetime is exceeded,
they traverse to this state. An expired key can be updated back to a
normal state.”h]”hŒ—Expired. Keys can have lifetimes set. If their lifetime is exceeded,
they traverse to this state. An expired key can be updated back to a
normal state.”…””}”(hjè  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K`hjä  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj™  ubj*  )”}”(hŒzRevoked. A key is put in this state by userspace action. It can't be
found or operated upon (apart from by unlinking it).
”h]”hÌ)”}”(hŒyRevoked. A key is put in this state by userspace action. It can't be
found or operated upon (apart from by unlinking it).”h]”hŒ{Revoked. A key is put in this state by userspace action. It canâ€™t be
found or operated upon (apart from by unlinking it).”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kdhjü  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj™  ubj*  )”}”(hŒFDead. The key's type was unregistered, and so the key is now useless.
”h]”hÌ)”}”(hŒEDead. The key's type was unregistered, and so the key is now useless.”h]”hŒGDead. The keyâ€™s type was unregistered, and so the key is now useless.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kghj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj™  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  Œ*”uh1j$  h³hÊh´KUhj•  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´KUhjƒ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjœ  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´K'hjá  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Khj³  h²hubhÌ)”}”(hŒjKeys in the last three states are subject to garbage collection.  See the
section on "Garbage collection".”h]”hŒnKeys in the last three states are subject to garbage collection.  See the
section on â€œGarbage collectionâ€.”…””}”(hjK  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kihj³  h²hubeh}”(h]”jB  ah ]”h"]”Œkey overview”ah$]”h&]”uh1hµhh·h²hh³hÊh´Kubh¶)”}”(hhh]”(h»)”}”(hŒKey Service Overview”h]”hŒKey Service Overview”…””}”(hjc  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  j^  uh1hºhj`  h²hh³hÊh´KnubhÌ)”}”(hŒ;The key service provides a number of features besides keys:”h]”hŒ;The key service provides a number of features besides keys:”…””}”(hjq  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kphj`  h²hubhø)”}”(hXe  *  The key service defines three special key types:

   (+) "keyring"

       Keyrings are special keys that contain a list of other keys. Keyring
       lists can be modified using various system calls. Keyrings should not
       be given a payload when created.

   (+) "user"

       A key of this type has a description and a payload that are arbitrary
       blobs of data. These can be created, updated and read by userspace,
       and aren't intended for use by kernel services.

   (+) "logon"

       Like a "user" key, a "logon" key has a payload that is an arbitrary
       blob of data. It is intended as a place to store secrets which are
       accessible to the kernel but not to userspace programs.

       The description can be arbitrary, but must be prefixed with a non-zero
       length string that describes the key "subclass". The subclass is
       separated from the rest of the description by a ':'. "logon" keys can
       be created and updated from userspace, but the payload is only
       readable from kernel space.

*  Each process subscribes to three keyrings: a thread-specific keyring, a
   process-specific keyring, and a session-specific keyring.

   The thread-specific keyring is discarded from the child when any sort of
   clone, fork, vfork or execve occurs. A new keyring is created only when
   required.

   The process-specific keyring is replaced with an empty one in the child on
   clone, fork, vfork unless CLONE_THREAD is supplied, in which case it is
   shared. execve also discards the process's process keyring and creates a
   new one.

   The session-specific keyring is persistent across clone, fork, vfork and
   execve, even when the latter executes a set-UID or set-GID binary. A
   process can, however, replace its current session keyring with a new one
   by using PR_JOIN_SESSION_KEYRING. It is permitted to request an anonymous
   new one, or to attempt to create or join one of a specific name.

   The ownership of the thread keyring changes when the real UID and GID of
   the thread changes.

*  Each user ID resident in the system holds two special keyrings: a user
   specific keyring and a default user session keyring. The default session
   keyring is initialised with a link to the user-specific keyring.

   When a process changes its real UID, if it used to have no session key, it
   will be subscribed to the default session key for the new UID.

   If a process attempts to access its session key when it doesn't have one,
   it will be subscribed to the default for its current UID.

*  Each user has two quotas against which the keys they own are tracked. One
   limits the total number of keys and keyrings, the other limits the total
   amount of description and payload space that can be consumed.

   The user can view information on this and other statistics through procfs
   files.  The root user may also alter the quota limits through sysctl files
   (see the section "New procfs files").

   Process-specific and thread-specific keyrings are not counted towards a
   user's quota.

   If a system call that modifies a key or keyring in some way would put the
   user over quota, the operation is refused and error EDQUOT is returned.

*  There's a system call interface by which userspace programs can create and
   manipulate keys and keyrings.

*  There's a kernel interface by which services can register types and search
   for keys.

*  There's a way for the a search done from the kernel to call back to
   userspace to request a key that can't be found in a process's keyrings.

*  An optional filesystem is available through which the key database can be
   viewed and manipulated.

”h]”j%  )”}”(hhh]”(j*  )”}”(hXã  The key service defines three special key types:

(+) "keyring"

    Keyrings are special keys that contain a list of other keys. Keyring
    lists can be modified using various system calls. Keyrings should not
    be given a payload when created.

(+) "user"

    A key of this type has a description and a payload that are arbitrary
    blobs of data. These can be created, updated and read by userspace,
    and aren't intended for use by kernel services.

(+) "logon"

    Like a "user" key, a "logon" key has a payload that is an arbitrary
    blob of data. It is intended as a place to store secrets which are
    accessible to the kernel but not to userspace programs.

    The description can be arbitrary, but must be prefixed with a non-zero
    length string that describes the key "subclass". The subclass is
    separated from the rest of the description by a ':'. "logon" keys can
    be created and updated from userspace, but the payload is only
    readable from kernel space.
”h]”(hÌ)”}”(hŒ0The key service defines three special key types:”h]”hŒ0The key service defines three special key types:”…””}”(hjŠ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Krhj†  ubhÌ)”}”(hŒ(+) "keyring"”h]”hŒ(+) â€œkeyringâ€”…””}”(hj˜  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kthj†  ubhø)”}”(hŒ¬Keyrings are special keys that contain a list of other keys. Keyring
lists can be modified using various system calls. Keyrings should not
be given a payload when created.
”h]”hÌ)”}”(hŒ«Keyrings are special keys that contain a list of other keys. Keyring
lists can be modified using various system calls. Keyrings should not
be given a payload when created.”h]”hŒ«Keyrings are special keys that contain a list of other keys. Keyring
lists can be modified using various system calls. Keyrings should not
be given a payload when created.”…””}”(hjª  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kvhj¦  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Kvhj†  ubhÌ)”}”(hŒ
(+) "user"”h]”hŒ(+) â€œuserâ€”…””}”(hj¾  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kzhj†  ubhø)”}”(hŒºA key of this type has a description and a payload that are arbitrary
blobs of data. These can be created, updated and read by userspace,
and aren't intended for use by kernel services.
”h]”hÌ)”}”(hŒ¹A key of this type has a description and a payload that are arbitrary
blobs of data. These can be created, updated and read by userspace,
and aren't intended for use by kernel services.”h]”hŒ»A key of this type has a description and a payload that are arbitrary
blobs of data. These can be created, updated and read by userspace,
and arenâ€™t intended for use by kernel services.”…””}”(hjÐ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K|hjÌ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´K|hj†  ubhÌ)”}”(hŒ(+) "logon"”h]”hŒ(+) â€œlogonâ€”…””}”(hjä  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K€hj†  ubhø)”}”(hXé  Like a "user" key, a "logon" key has a payload that is an arbitrary
blob of data. It is intended as a place to store secrets which are
accessible to the kernel but not to userspace programs.

The description can be arbitrary, but must be prefixed with a non-zero
length string that describes the key "subclass". The subclass is
separated from the rest of the description by a ':'. "logon" keys can
be created and updated from userspace, but the payload is only
readable from kernel space.
”h]”(hÌ)”}”(hŒ¾Like a "user" key, a "logon" key has a payload that is an arbitrary
blob of data. It is intended as a place to store secrets which are
accessible to the kernel but not to userspace programs.”h]”hŒÆLike a â€œuserâ€ key, a â€œlogonâ€ key has a payload that is an arbitrary
blob of data. It is intended as a place to store secrets which are
accessible to the kernel but not to userspace programs.”…””}”(hjö  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K‚hjò  ubhÌ)”}”(hX(  The description can be arbitrary, but must be prefixed with a non-zero
length string that describes the key "subclass". The subclass is
separated from the rest of the description by a ':'. "logon" keys can
be created and updated from userspace, but the payload is only
readable from kernel space.”h]”hX4  The description can be arbitrary, but must be prefixed with a non-zero
length string that describes the key â€œsubclassâ€. The subclass is
separated from the rest of the description by a â€˜:â€™. â€œlogonâ€ keys can
be created and updated from userspace, but the payload is only
readable from kernel space.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K†hjò  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´K‚hj†  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hXÅ  Each process subscribes to three keyrings: a thread-specific keyring, a
process-specific keyring, and a session-specific keyring.

The thread-specific keyring is discarded from the child when any sort of
clone, fork, vfork or execve occurs. A new keyring is created only when
required.

The process-specific keyring is replaced with an empty one in the child on
clone, fork, vfork unless CLONE_THREAD is supplied, in which case it is
shared. execve also discards the process's process keyring and creates a
new one.

The session-specific keyring is persistent across clone, fork, vfork and
execve, even when the latter executes a set-UID or set-GID binary. A
process can, however, replace its current session keyring with a new one
by using PR_JOIN_SESSION_KEYRING. It is permitted to request an anonymous
new one, or to attempt to create or join one of a specific name.

The ownership of the thread keyring changes when the real UID and GID of
the thread changes.
”h]”(hÌ)”}”(hŒEach process subscribes to three keyrings: a thread-specific keyring, a
process-specific keyring, and a session-specific keyring.”h]”hŒEach process subscribes to three keyrings: a thread-specific keyring, a
process-specific keyring, and a session-specific keyring.”…””}”(hj"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KŒhj  ubhÌ)”}”(hŒšThe thread-specific keyring is discarded from the child when any sort of
clone, fork, vfork or execve occurs. A new keyring is created only when
required.”h]”hŒšThe thread-specific keyring is discarded from the child when any sort of
clone, fork, vfork or execve occurs. A new keyring is created only when
required.”…””}”(hj0  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Khj  ubhÌ)”}”(hŒäThe process-specific keyring is replaced with an empty one in the child on
clone, fork, vfork unless CLONE_THREAD is supplied, in which case it is
shared. execve also discards the process's process keyring and creates a
new one.”h]”hŒæThe process-specific keyring is replaced with an empty one in the child on
clone, fork, vfork unless CLONE_THREAD is supplied, in which case it is
shared. execve also discards the processâ€™s process keyring and creates a
new one.”…””}”(hj>  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K“hj  ubhÌ)”}”(hXa  The session-specific keyring is persistent across clone, fork, vfork and
execve, even when the latter executes a set-UID or set-GID binary. A
process can, however, replace its current session keyring with a new one
by using PR_JOIN_SESSION_KEYRING. It is permitted to request an anonymous
new one, or to attempt to create or join one of a specific name.”h]”hXa  The session-specific keyring is persistent across clone, fork, vfork and
execve, even when the latter executes a set-UID or set-GID binary. A
process can, however, replace its current session keyring with a new one
by using PR_JOIN_SESSION_KEYRING. It is permitted to request an anonymous
new one, or to attempt to create or join one of a specific name.”…””}”(hjL  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K˜hj  ubhÌ)”}”(hŒ\The ownership of the thread keyring changes when the real UID and GID of
the thread changes.”h]”hŒ\The ownership of the thread keyring changes when the real UID and GID of
the thread changes.”…””}”(hjZ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kžhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hXá  Each user ID resident in the system holds two special keyrings: a user
specific keyring and a default user session keyring. The default session
keyring is initialised with a link to the user-specific keyring.

When a process changes its real UID, if it used to have no session key, it
will be subscribed to the default session key for the new UID.

If a process attempts to access its session key when it doesn't have one,
it will be subscribed to the default for its current UID.
”h]”(hÌ)”}”(hŒÐEach user ID resident in the system holds two special keyrings: a user
specific keyring and a default user session keyring. The default session
keyring is initialised with a link to the user-specific keyring.”h]”hŒÐEach user ID resident in the system holds two special keyrings: a user
specific keyring and a default user session keyring. The default session
keyring is initialised with a link to the user-specific keyring.”…””}”(hjr  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¡hjn  ubhÌ)”}”(hŒ‰When a process changes its real UID, if it used to have no session key, it
will be subscribed to the default session key for the new UID.”h]”hŒ‰When a process changes its real UID, if it used to have no session key, it
will be subscribed to the default session key for the new UID.”…””}”(hj€  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¥hjn  ubhÌ)”}”(hŒƒIf a process attempts to access its session key when it doesn't have one,
it will be subscribed to the default for its current UID.”h]”hŒ…If a process attempts to access its session key when it doesnâ€™t have one,
it will be subscribed to the default for its current UID.”…””}”(hjŽ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¨hjn  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hXw  Each user has two quotas against which the keys they own are tracked. One
limits the total number of keys and keyrings, the other limits the total
amount of description and payload space that can be consumed.

The user can view information on this and other statistics through procfs
files.  The root user may also alter the quota limits through sysctl files
(see the section "New procfs files").

Process-specific and thread-specific keyrings are not counted towards a
user's quota.

If a system call that modifies a key or keyring in some way would put the
user over quota, the operation is refused and error EDQUOT is returned.
”h]”(hÌ)”}”(hŒÐEach user has two quotas against which the keys they own are tracked. One
limits the total number of keys and keyrings, the other limits the total
amount of description and payload space that can be consumed.”h]”hŒÐEach user has two quotas against which the keys they own are tracked. One
limits the total number of keys and keyrings, the other limits the total
amount of description and payload space that can be consumed.”…””}”(hj¦  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K«hj¢  ubhÌ)”}”(hŒºThe user can view information on this and other statistics through procfs
files.  The root user may also alter the quota limits through sysctl files
(see the section "New procfs files").”h]”hŒ¾The user can view information on this and other statistics through procfs
files.  The root user may also alter the quota limits through sysctl files
(see the section â€œNew procfs filesâ€).”…””}”(hj´  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¯hj¢  ubhÌ)”}”(hŒUProcess-specific and thread-specific keyrings are not counted towards a
user's quota.”h]”hŒWProcess-specific and thread-specific keyrings are not counted towards a
userâ€™s quota.”…””}”(hjÂ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K³hj¢  ubhÌ)”}”(hŒ‘If a system call that modifies a key or keyring in some way would put the
user over quota, the operation is refused and error EDQUOT is returned.”h]”hŒ‘If a system call that modifies a key or keyring in some way would put the
user over quota, the operation is refused and error EDQUOT is returned.”…””}”(hjÐ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¶hj¢  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hŒiThere's a system call interface by which userspace programs can create and
manipulate keys and keyrings.
”h]”hÌ)”}”(hŒhThere's a system call interface by which userspace programs can create and
manipulate keys and keyrings.”h]”hŒjThereâ€™s a system call interface by which userspace programs can create and
manipulate keys and keyrings.”…””}”(hjè  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¹hjä  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hŒUThere's a kernel interface by which services can register types and search
for keys.
”h]”hÌ)”}”(hŒTThere's a kernel interface by which services can register types and search
for keys.”h]”hŒVThereâ€™s a kernel interface by which services can register types and search
for keys.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¼hjü  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hŒŒThere's a way for the a search done from the kernel to call back to
userspace to request a key that can't be found in a process's keyrings.
”h]”hÌ)”}”(hŒ‹There's a way for the a search done from the kernel to call back to
userspace to request a key that can't be found in a process's keyrings.”h]”hŒ‘Thereâ€™s a way for the a search done from the kernel to call back to
userspace to request a key that canâ€™t be found in a processâ€™s keyrings.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K¿hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubj*  )”}”(hŒcAn optional filesystem is available through which the key database can be
viewed and manipulated.

”h]”hÌ)”}”(hŒaAn optional filesystem is available through which the key database can be
viewed and manipulated.”h]”hŒaAn optional filesystem is available through which the key database can be
viewed and manipulated.”…””}”(hj0  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÂhj,  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjƒ  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´Krhj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Krhj`  h²hubeh}”(h]”jd  ah ]”h"]”Œkey service overview”ah$]”h&]”uh1hµhh·h²hh³hÊh´Knubh¶)”}”(hhh]”(h»)”}”(hŒKey Access Permissions”h]”hŒKey Access Permissions”…””}”(hjZ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  j€  uh1hºhjW  h²hh³hÊh´KÇubhÌ)”}”(hŒåKeys have an owner user ID, a group access ID, and a permissions mask. The mask
has up to eight bits each for possessor, user, group and other access. Only
six of each set of eight bits are defined. These permissions granted are:”h]”hŒåKeys have an owner user ID, a group access ID, and a permissions mask. The mask
has up to eight bits each for possessor, user, group and other access. Only
six of each set of eight bits are defined. These permissions granted are:”…””}”(hjh  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÉhjW  h²hubhø)”}”(hX  *  View

   This permits a key or keyring's attributes to be viewed - including key
   type and description.

*  Read

   This permits a key's payload to be viewed or a keyring's list of linked
   keys.

*  Write

   This permits a key's payload to be instantiated or updated, or it allows a
   link to be added to or removed from a keyring.

*  Search

   This permits keyrings to be searched and keys to be found. Searches can
   only recurse into nested keyrings that have search permission set.

*  Link

   This permits a key or keyring to be linked to. To create a link from a
   keyring to a key, a process must have Write permission on the keyring and
   Link permission on the key.

*  Set Attribute

   This permits a key's UID, GID and permissions mask to be changed.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒdView

This permits a key or keyring's attributes to be viewed - including key
type and description.
”h]”(hÌ)”}”(hŒView”h]”hŒView”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÍhj}  ubhÌ)”}”(hŒ]This permits a key or keyring's attributes to be viewed - including key
type and description.”h]”hŒ_This permits a key or keyringâ€™s attributes to be viewed - including key
type and description.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÏhj}  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjz  ubj*  )”}”(hŒTRead

This permits a key's payload to be viewed or a keyring's list of linked
keys.
”h]”(hÌ)”}”(hŒRead”h]”hŒRead”…””}”(hj§  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÒhj£  ubhÌ)”}”(hŒMThis permits a key's payload to be viewed or a keyring's list of linked
keys.”h]”hŒQThis permits a keyâ€™s payload to be viewed or a keyringâ€™s list of linked
keys.”…””}”(hjµ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÔhj£  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjz  ubj*  )”}”(hŒWrite

This permits a key's payload to be instantiated or updated, or it allows a
link to be added to or removed from a keyring.
”h]”(hÌ)”}”(hŒWrite”h]”hŒWrite”…””}”(hjÍ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´K×hjÉ  ubhÌ)”}”(hŒyThis permits a key's payload to be instantiated or updated, or it allows a
link to be added to or removed from a keyring.”h]”hŒ{This permits a keyâ€™s payload to be instantiated or updated, or it allows a
link to be added to or removed from a keyring.”…””}”(hjÛ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÙhjÉ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjz  ubj*  )”}”(hŒ“Search

This permits keyrings to be searched and keys to be found. Searches can
only recurse into nested keyrings that have search permission set.
”h]”(hÌ)”}”(hŒSearch”h]”hŒSearch”…””}”(hjó  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÜhjï  ubhÌ)”}”(hŒŠThis permits keyrings to be searched and keys to be found. Searches can
only recurse into nested keyrings that have search permission set.”h]”hŒŠThis permits keyrings to be searched and keys to be found. Searches can
only recurse into nested keyrings that have search permission set.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KÞhjï  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjz  ubj*  )”}”(hŒ³Link

This permits a key or keyring to be linked to. To create a link from a
keyring to a key, a process must have Write permission on the keyring and
Link permission on the key.
”h]”(hÌ)”}”(hŒLink”h]”hŒLink”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Káhj  ubhÌ)”}”(hŒ¬This permits a key or keyring to be linked to. To create a link from a
keyring to a key, a process must have Write permission on the keyring and
Link permission on the key.”h]”hŒ¬This permits a key or keyring to be linked to. To create a link from a
keyring to a key, a process must have Write permission on the keyring and
Link permission on the key.”…””}”(hj'  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kãhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjz  ubj*  )”}”(hŒQSet Attribute

This permits a key's UID, GID and permissions mask to be changed.
”h]”(hÌ)”}”(hŒSet Attribute”h]”hŒSet Attribute”…””}”(hj?  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kçhj;  ubhÌ)”}”(hŒAThis permits a key's UID, GID and permissions mask to be changed.”h]”hŒCThis permits a keyâ€™s UID, GID and permissions mask to be changed.”…””}”(hjM  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kéhj;  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjz  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´KÍhjv  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´KÍhjW  h²hubhÌ)”}”(hŒ…For changing the ownership, group ID or permissions mask, being the owner of
the key or having the sysadmin capability is sufficient.”h]”hŒ…For changing the ownership, group ID or permissions mask, being the owner of
the key or having the sysadmin capability is sufficient.”…””}”(hjm  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´KëhjW  h²hubeh}”(h]”j†  ah ]”h"]”Œkey access permissions”ah$]”h&]”uh1hµhh·h²hh³hÊh´KÇubh¶)”}”(hhh]”(h»)”}”(hŒSELinux Support”h]”hŒSELinux Support”…””}”(hj…  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  j¢  uh1hºhj‚  h²hh³hÊh´KðubhÌ)”}”(hX”  The security class "key" has been added to SELinux so that mandatory access
controls can be applied to keys created within various contexts.  This support
is preliminary, and is likely to change quite significantly in the near future.
Currently, all of the basic permissions explained above are provided in SELinux
as well; SELinux is simply invoked after all basic permission checks have been
performed.”h]”hX˜  The security class â€œkeyâ€ has been added to SELinux so that mandatory access
controls can be applied to keys created within various contexts.  This support
is preliminary, and is likely to change quite significantly in the near future.
Currently, all of the basic permissions explained above are provided in SELinux
as well; SELinux is simply invoked after all basic permission checks have been
performed.”…””}”(hj“  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kòhj‚  h²hubhÌ)”}”(hXÙ  The value of the file /proc/self/attr/keycreate influences the labeling of
newly-created keys.  If the contents of that file correspond to an SELinux
security context, then the key will be assigned that context.  Otherwise, the
key will be assigned the current context of the task that invoked the key
creation request.  Tasks must be granted explicit permission to assign a
particular context to newly-created keys, using the "create" permission in the
key security class.”h]”hXÝ  The value of the file /proc/self/attr/keycreate influences the labeling of
newly-created keys.  If the contents of that file correspond to an SELinux
security context, then the key will be assigned that context.  Otherwise, the
key will be assigned the current context of the task that invoked the key
creation request.  Tasks must be granted explicit permission to assign a
particular context to newly-created keys, using the â€œcreateâ€ permission in the
key security class.”…””}”(hj¡  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Kùhj‚  h²hubhÌ)”}”(hX"  The default keyrings associated with users will be labeled with the default
context of the user if and only if the login programs have been instrumented to
properly initialize keycreate during the login process.  Otherwise, they will
be labeled with the context of the login program itself.”h]”hX"  The default keyrings associated with users will be labeled with the default
context of the user if and only if the login programs have been instrumented to
properly initialize keycreate during the login process.  Otherwise, they will
be labeled with the context of the login program itself.”…””}”(hj¯  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj‚  h²hubhÌ)”}”(hŒÉNote, however, that the default keyrings associated with the root user are
labeled with the default kernel context, since they are created early in the
boot process, before root has a chance to log in.”h]”hŒÉNote, however, that the default keyrings associated with the root user are
labeled with the default kernel context, since they are created early in the
boot process, before root has a chance to log in.”…””}”(hj½  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj‚  h²hubhÌ)”}”(hŒ£The keyrings associated with new threads are each labeled with the context of
their associated thread, and both session and process keyrings are handled
similarly.”h]”hŒ£The keyrings associated with new threads are each labeled with the context of
their associated thread, and both session and process keyrings are handled
similarly.”…””}”(hjË  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M
hj‚  h²hubeh}”(h]”j¨  ah ]”h"]”Œselinux support”ah$]”h&]”uh1hµhh·h²hh³hÊh´Kðubh¶)”}”(hhh]”(h»)”}”(hŒNew ProcFS Files”h]”hŒNew ProcFS Files”…””}”(hjã  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  jÄ  uh1hºhjà  h²hh³hÊh´MubhÌ)”}”(hŒoTwo files have been added to procfs by which an administrator can find out
about the status of the key service:”h]”hŒoTwo files have been added to procfs by which an administrator can find out
about the status of the key service:”…””}”(hjñ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjà  h²hubhø)”}”(hXô  *  /proc/keys

   This lists the keys that are currently viewable by the task reading the
   file, giving information about their type, description and permissions.
   It is not possible to view the payload of the key this way, though some
   information about it may be given.

   The only keys included in the list are those that grant View permission to
   the reading process whether or not it possesses them.  Note that LSM
   security checks are still performed, and may further filter out keys that
   the current process is not authorised to view.

   The contents of the file look like this::

      SERIAL   FLAGS  USAGE EXPY PERM     UID   GID   TYPE      DESCRIPTION: SUMMARY
      00000001 I-----    39 perm 1f3f0000     0     0 keyring   _uid_ses.0: 1/4
      00000002 I-----     2 perm 1f3f0000     0     0 keyring   _uid.0: empty
      00000007 I-----     1 perm 1f3f0000     0     0 keyring   _pid.1: empty
      0000018d I-----     1 perm 1f3f0000     0     0 keyring   _pid.412: empty
      000004d2 I--Q--     1 perm 1f3f0000    32    -1 keyring   _uid.32: 1/4
      000004d3 I--Q--     3 perm 1f3f0000    32    -1 keyring   _uid_ses.32: empty
      00000892 I--QU-     1 perm 1f000000     0     0 user      metal:copper: 0
      00000893 I--Q-N     1  35s 1f3f0000     0     0 user      metal:silver: 0
      00000894 I--Q--     1  10h 003f0000     0     0 user      metal:gold: 0

   The flags are::

      I       Instantiated
      R       Revoked
      D       Dead
      Q       Contributes to user's quota
      U       Under construction by callback to userspace
      N       Negative key


*  /proc/key-users

   This file lists the tracking data for each user that has at least one key
   on the system.  Such data includes quota information and statistics::

      [root@andromeda root]# cat /proc/key-users
      0:     46 45/45 1/100 13/10000
      29:     2 2/2 2/100 40/10000
      32:     2 2/2 2/100 40/10000
      38:     2 2/2 2/100 40/10000

   The format of each line is::

      <UID>:                  User ID to which this applies
      <usage>                 Structure refcount
      <inst>/<keys>           Total number of keys and number instantiated
      <keys>/<max>            Key count quota
      <bytes>/<max>           Key size quota

”h]”j%  )”}”(hhh]”(j*  )”}”(hX  /proc/keys

This lists the keys that are currently viewable by the task reading the
file, giving information about their type, description and permissions.
It is not possible to view the payload of the key this way, though some
information about it may be given.

The only keys included in the list are those that grant View permission to
the reading process whether or not it possesses them.  Note that LSM
security checks are still performed, and may further filter out keys that
the current process is not authorised to view.

The contents of the file look like this::

   SERIAL   FLAGS  USAGE EXPY PERM     UID   GID   TYPE      DESCRIPTION: SUMMARY
   00000001 I-----    39 perm 1f3f0000     0     0 keyring   _uid_ses.0: 1/4
   00000002 I-----     2 perm 1f3f0000     0     0 keyring   _uid.0: empty
   00000007 I-----     1 perm 1f3f0000     0     0 keyring   _pid.1: empty
   0000018d I-----     1 perm 1f3f0000     0     0 keyring   _pid.412: empty
   000004d2 I--Q--     1 perm 1f3f0000    32    -1 keyring   _uid.32: 1/4
   000004d3 I--Q--     3 perm 1f3f0000    32    -1 keyring   _uid_ses.32: empty
   00000892 I--QU-     1 perm 1f000000     0     0 user      metal:copper: 0
   00000893 I--Q-N     1  35s 1f3f0000     0     0 user      metal:silver: 0
   00000894 I--Q--     1  10h 003f0000     0     0 user      metal:gold: 0

The flags are::

   I       Instantiated
   R       Revoked
   D       Dead
   Q       Contributes to user's quota
   U       Under construction by callback to userspace
   N       Negative key

”h]”(hÌ)”}”(hŒ
/proc/keys”h]”hŒ
/proc/keys”…””}”(hj
	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj	  ubhÌ)”}”(hŒúThis lists the keys that are currently viewable by the task reading the
file, giving information about their type, description and permissions.
It is not possible to view the payload of the key this way, though some
information about it may be given.”h]”hŒúThis lists the keys that are currently viewable by the task reading the
file, giving information about their type, description and permissions.
It is not possible to view the payload of the key this way, though some
information about it may be given.”…””}”(hj	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj	  ubhÌ)”}”(hX  The only keys included in the list are those that grant View permission to
the reading process whether or not it possesses them.  Note that LSM
security checks are still performed, and may further filter out keys that
the current process is not authorised to view.”h]”hX  The only keys included in the list are those that grant View permission to
the reading process whether or not it possesses them.  Note that LSM
security checks are still performed, and may further filter out keys that
the current process is not authorised to view.”…””}”(hj&	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj	  ubhÌ)”}”(hŒ)The contents of the file look like this::”h]”hŒ(The contents of the file look like this:”…””}”(hj4	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M!hj	  ubhŒliteral_block”“”)”}”(hXâ  SERIAL   FLAGS  USAGE EXPY PERM     UID   GID   TYPE      DESCRIPTION: SUMMARY
00000001 I-----    39 perm 1f3f0000     0     0 keyring   _uid_ses.0: 1/4
00000002 I-----     2 perm 1f3f0000     0     0 keyring   _uid.0: empty
00000007 I-----     1 perm 1f3f0000     0     0 keyring   _pid.1: empty
0000018d I-----     1 perm 1f3f0000     0     0 keyring   _pid.412: empty
000004d2 I--Q--     1 perm 1f3f0000    32    -1 keyring   _uid.32: 1/4
000004d3 I--Q--     3 perm 1f3f0000    32    -1 keyring   _uid_ses.32: empty
00000892 I--QU-     1 perm 1f000000     0     0 user      metal:copper: 0
00000893 I--Q-N     1  35s 1f3f0000     0     0 user      metal:silver: 0
00000894 I--Q--     1  10h 003f0000     0     0 user      metal:gold: 0”h]”hXâ  SERIAL   FLAGS  USAGE EXPY PERM     UID   GID   TYPE      DESCRIPTION: SUMMARY
00000001 I-----    39 perm 1f3f0000     0     0 keyring   _uid_ses.0: 1/4
00000002 I-----     2 perm 1f3f0000     0     0 keyring   _uid.0: empty
00000007 I-----     1 perm 1f3f0000     0     0 keyring   _pid.1: empty
0000018d I-----     1 perm 1f3f0000     0     0 keyring   _pid.412: empty
000004d2 I--Q--     1 perm 1f3f0000    32    -1 keyring   _uid.32: 1/4
000004d3 I--Q--     3 perm 1f3f0000    32    -1 keyring   _uid_ses.32: empty
00000892 I--QU-     1 perm 1f000000     0     0 user      metal:copper: 0
00000893 I--Q-N     1  35s 1f3f0000     0     0 user      metal:silver: 0
00000894 I--Q--     1  10h 003f0000     0     0 user      metal:gold: 0”…””}”hjD	  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1jB	  h³hÊh´M#hj	  ubhÌ)”}”(hŒThe flags are::”h]”hŒThe flags are:”…””}”(hjT	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M.hj	  ubjC	  )”}”(hŒžI       Instantiated
R       Revoked
D       Dead
Q       Contributes to user's quota
U       Under construction by callback to userspace
N       Negative key”h]”hŒžI       Instantiated
R       Revoked
D       Dead
Q       Contributes to user's quota
U       Under construction by callback to userspace
N       Negative key”…””}”hjb	  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M0hj	  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj	  ubj*  )”}”(hXv  /proc/key-users

This file lists the tracking data for each user that has at least one key
on the system.  Such data includes quota information and statistics::

   [root@andromeda root]# cat /proc/key-users
   0:     46 45/45 1/100 13/10000
   29:     2 2/2 2/100 40/10000
   32:     2 2/2 2/100 40/10000
   38:     2 2/2 2/100 40/10000

The format of each line is::

   <UID>:                  User ID to which this applies
   <usage>                 Structure refcount
   <inst>/<keys>           Total number of keys and number instantiated
   <keys>/<max>            Key count quota
   <bytes>/<max>           Key size quota

”h]”(hÌ)”}”(hŒ/proc/key-users”h]”hŒ/proc/key-users”…””}”(hjz	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M8hjv	  ubhÌ)”}”(hŒThis file lists the tracking data for each user that has at least one key
on the system.  Such data includes quota information and statistics::”h]”hŒŽThis file lists the tracking data for each user that has at least one key
on the system.  Such data includes quota information and statistics:”…””}”(hjˆ	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M:hjv	  ubjC	  )”}”(hŒ [root@andromeda root]# cat /proc/key-users
0:     46 45/45 1/100 13/10000
29:     2 2/2 2/100 40/10000
32:     2 2/2 2/100 40/10000
38:     2 2/2 2/100 40/10000”h]”hŒ [root@andromeda root]# cat /proc/key-users
0:     46 45/45 1/100 13/10000
29:     2 2/2 2/100 40/10000
32:     2 2/2 2/100 40/10000
38:     2 2/2 2/100 40/10000”…””}”hj–	  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M=hjv	  ubhÌ)”}”(hŒThe format of each line is::”h]”hŒThe format of each line is:”…””}”(hj¤	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MChjv	  ubjC	  )”}”(hŒô<UID>:                  User ID to which this applies
<usage>                 Structure refcount
<inst>/<keys>           Total number of keys and number instantiated
<keys>/<max>            Key count quota
<bytes>/<max>           Key size quota”h]”hŒô<UID>:                  User ID to which this applies
<usage>                 Structure refcount
<inst>/<keys>           Total number of keys and number instantiated
<keys>/<max>            Key count quota
<bytes>/<max>           Key size quota”…””}”hj²	  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MEhjv	  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj	  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´Mhjÿ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Mhjà  h²hubhÌ)”}”(hŒcFour new sysctl files have been added also for the purpose of controlling the
quota limits on keys:”h]”hŒcFour new sysctl files have been added also for the purpose of controlling the
quota limits on keys:”…””}”(hjÒ	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MLhjà  h²hubhø)”}”(hXî  *  /proc/sys/kernel/keys/root_maxkeys
   /proc/sys/kernel/keys/root_maxbytes

   These files hold the maximum number of keys that root may have and the
   maximum total number of bytes of data that root may have stored in those
   keys.

*  /proc/sys/kernel/keys/maxkeys
   /proc/sys/kernel/keys/maxbytes

   These files hold the maximum number of keys that each non-root user may
   have and the maximum total number of bytes of data that each of those
   users may have stored in their keys.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒÞ/proc/sys/kernel/keys/root_maxkeys
/proc/sys/kernel/keys/root_maxbytes

These files hold the maximum number of keys that root may have and the
maximum total number of bytes of data that root may have stored in those
keys.
”h]”(hÌ)”}”(hŒF/proc/sys/kernel/keys/root_maxkeys
/proc/sys/kernel/keys/root_maxbytes”h]”hŒF/proc/sys/kernel/keys/root_maxkeys
/proc/sys/kernel/keys/root_maxbytes”…””•      }”(hjë	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MOhjç	  ubhÌ)”}”(hŒ•These files hold the maximum number of keys that root may have and the
maximum total number of bytes of data that root may have stored in those
keys.”h]”hŒ•These files hold the maximum number of keys that root may have and the
maximum total number of bytes of data that root may have stored in those
keys.”…””}”(hjù	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MRhjç	  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjä	  ubj*  )”}”(hŒñ/proc/sys/kernel/keys/maxkeys
/proc/sys/kernel/keys/maxbytes

These files hold the maximum number of keys that each non-root user may
have and the maximum total number of bytes of data that each of those
users may have stored in their keys.
”h]”(hÌ)”}”(hŒ</proc/sys/kernel/keys/maxkeys
/proc/sys/kernel/keys/maxbytes”h]”hŒ</proc/sys/kernel/keys/maxkeys
/proc/sys/kernel/keys/maxbytes”…””}”(hj
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MVhj
  ubhÌ)”}”(hŒ²These files hold the maximum number of keys that each non-root user may
have and the maximum total number of bytes of data that each of those
users may have stored in their keys.”h]”hŒ²These files hold the maximum number of keys that each non-root user may
have and the maximum total number of bytes of data that each of those
users may have stored in their keys.”…””}”(hj
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MYhj
  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjä	  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´MOhjà	  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´MOhjà  h²hubhÌ)”}”(hŒbRoot may alter these by writing each new limit as a decimal number string to
the appropriate file.”h]”hŒbRoot may alter these by writing each new limit as a decimal number string to
the appropriate file.”…””}”(hj?
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M]hjà  h²hubeh}”(h]”jÊ  ah ]”h"]”Œnew procfs files”ah$]”h&]”uh1hµhh·h²hh³hÊh´Mubh¶)”}”(hhh]”(h»)”}”(hŒUserspace System Call Interface”h]”hŒUserspace System Call Interface”…””}”(hjW
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  jæ  uh1hºhjT
  h²hh³hÊh´MbubhÌ)”}”(hŒ¤Userspace can manipulate keys directly through three new syscalls: add_key,
request_key and keyctl. The latter provides a number of functions for
manipulating keys.”h]”hŒ¤Userspace can manipulate keys directly through three new syscalls: add_key,
request_key and keyctl. The latter provides a number of functions for
manipulating keys.”…””}”(hje
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MdhjT
  h²hubhÌ)”}”(hŒýWhen referring to a key directly, userspace programs should use the key's
serial number (a positive 32-bit integer). However, there are some special
values available for referring to special keys and keyrings that relate to the
process making the call::”h]”hŒþWhen referring to a key directly, userspace programs should use the keyâ€™s
serial number (a positive 32-bit integer). However, there are some special
values available for referring to special keys and keyrings that relate to the
process making the call:”…””}”(hjs
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhhjT
  h²hubjC	  )”}”(hXl  CONSTANT                        VALUE   KEY REFERENCED
==============================  ======  ===========================
KEY_SPEC_THREAD_KEYRING         -1      thread-specific keyring
KEY_SPEC_PROCESS_KEYRING        -2      process-specific keyring
KEY_SPEC_SESSION_KEYRING        -3      session-specific keyring
KEY_SPEC_USER_KEYRING           -4      UID-specific keyring
KEY_SPEC_USER_SESSION_KEYRING   -5      UID-session keyring
KEY_SPEC_GROUP_KEYRING          -6      GID-specific keyring
KEY_SPEC_REQKEY_AUTH_KEY        -7      assumed request_key()
                                          authorisation key”h]”hXl  CONSTANT                        VALUE   KEY REFERENCED
==============================  ======  ===========================
KEY_SPEC_THREAD_KEYRING         -1      thread-specific keyring
KEY_SPEC_PROCESS_KEYRING        -2      process-specific keyring
KEY_SPEC_SESSION_KEYRING        -3      session-specific keyring
KEY_SPEC_USER_KEYRING           -4      UID-specific keyring
KEY_SPEC_USER_SESSION_KEYRING   -5      UID-session keyring
KEY_SPEC_GROUP_KEYRING          -6      GID-specific keyring
KEY_SPEC_REQKEY_AUTH_KEY        -7      assumed request_key()
                                          authorisation key”…””}”hj
  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MmhjT
  h²hubhÌ)”}”(hŒThe main syscalls are:”h]”hŒThe main syscalls are:”…””}”(hj
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MyhjT
  h²hubhø)”}”(hXý
  *  Create a new key of given type, description and payload and add it to the
   nominated keyring::

      key_serial_t add_key(const char *type, const char *desc,
                           const void *payload, size_t plen,
                           key_serial_t keyring);

   If a key of the same type and description as that proposed already exists
   in the keyring, this will try to update it with the given payload, or it
   will return error EEXIST if that function is not supported by the key
   type. The process must also have permission to write to the key to be able
   to update it. The new key will have all user permissions granted and no
   group or third party permissions.

   Otherwise, this will attempt to create a new key of the specified type and
   description, and to instantiate it with the supplied payload and attach it
   to the keyring. In this case, an error will be generated if the process
   does not have permission to write to the keyring.

   If the key type supports it, if the description is NULL or an empty
   string, the key type will try and generate a description from the content
   of the payload.

   The payload is optional, and the pointer can be NULL if not required by
   the type. The payload is plen in size, and plen can be zero for an empty
   payload.

   A new keyring can be generated by setting type "keyring", the keyring name
   as the description (or NULL) and setting the payload to NULL.

   User defined keys can be created by specifying type "user". It is
   recommended that a user defined key's description by prefixed with a type
   ID and a colon, such as "krb5tgt:" for a Kerberos 5 ticket granting
   ticket.

   Any other type must have been registered with the kernel in advance by a
   kernel service such as a filesystem.

   The ID of the new or updated key is returned if successful.


*  Search the process's keyrings for a key, potentially calling out to
   userspace to create it::

      key_serial_t request_key(const char *type, const char *description,
                               const char *callout_info,
                               key_serial_t dest_keyring);

   This function searches all the process's keyrings in the order thread,
   process, session for a matching key. This works very much like
   KEYCTL_SEARCH, including the optional attachment of the discovered key to
   a keyring.

   If a key cannot be found, and if callout_info is not NULL, then
   /sbin/request-key will be invoked in an attempt to obtain a key. The
   callout_info string will be passed as an argument to the program.

   To link a key into the destination keyring the key must grant link
   permission on the key to the caller and the keyring must grant write
   permission.

   See also Documentation/security/keys/request-key.rst.

”h]”j%  )”}”(hhh]”(j*  )”}”(hXî  Create a new key of given type, description and payload and add it to the
nominated keyring::

   key_serial_t add_key(const char *type, const char *desc,
                        const void *payload, size_t plen,
                        key_serial_t keyring);

If a key of the same type and description as that proposed already exists
in the keyring, this will try to update it with the given payload, or it
will return error EEXIST if that function is not supported by the key
type. The process must also have permission to write to the key to be able
to update it. The new key will have all user permissions granted and no
group or third party permissions.

Otherwise, this will attempt to create a new key of the specified type and
description, and to instantiate it with the supplied payload and attach it
to the keyring. In this case, an error will be generated if the process
does not have permission to write to the keyring.

If the key type supports it, if the description is NULL or an empty
string, the key type will try and generate a description from the content
of the payload.

The payload is optional, and the pointer can be NULL if not required by
the type. The payload is plen in size, and plen can be zero for an empty
payload.

A new keyring can be generated by setting type "keyring", the keyring name
as the description (or NULL) and setting the payload to NULL.

User defined keys can be created by specifying type "user". It is
recommended that a user defined key's description by prefixed with a type
ID and a colon, such as "krb5tgt:" for a Kerberos 5 ticket granting
ticket.

Any other type must have been registered with the kernel in advance by a
kernel service such as a filesystem.

The ID of the new or updated key is returned if successful.

”h]”(hÌ)”}”(hŒ]Create a new key of given type, description and payload and add it to the
nominated keyring::”h]”hŒ\Create a new key of given type, description and payload and add it to the
nominated keyring:”…””}”(hj¨
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M{hj¤
  ubjC	  )”}”(hŒ›key_serial_t add_key(const char *type, const char *desc,
                     const void *payload, size_t plen,
                     key_serial_t keyring);”h]”hŒ›key_serial_t add_key(const char *type, const char *desc,
                     const void *payload, size_t plen,
                     key_serial_t keyring);”…””}”hj¶
  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M~hj¤
  ubhÌ)”}”(hX  If a key of the same type and description as that proposed already exists
in the keyring, this will try to update it with the given payload, or it
will return error EEXIST if that function is not supported by the key
type. The process must also have permission to write to the key to be able
to update it. The new key will have all user permissions granted and no
group or third party permissions.”h]”hX  If a key of the same type and description as that proposed already exists
in the keyring, this will try to update it with the given payload, or it
will return error EEXIST if that function is not supported by the key
type. The process must also have permission to write to the key to be able
to update it. The new key will have all user permissions granted and no
group or third party permissions.”…””}”(hjÄ
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M‚hj¤
  ubhÌ)”}”(hX  Otherwise, this will attempt to create a new key of the specified type and
description, and to instantiate it with the supplied payload and attach it
to the keyring. In this case, an error will be generated if the process
does not have permission to write to the keyring.”h]”hX  Otherwise, this will attempt to create a new key of the specified type and
description, and to instantiate it with the supplied payload and attach it
to the keyring. In this case, an error will be generated if the process
does not have permission to write to the keyring.”…””}”(hjÒ
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M‰hj¤
  ubhÌ)”}”(hŒIf the key type supports it, if the description is NULL or an empty
string, the key type will try and generate a description from the content
of the payload.”h]”hŒIf the key type supports it, if the description is NULL or an empty
string, the key type will try and generate a description from the content
of the payload.”…””}”(hjà
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MŽhj¤
  ubhÌ)”}”(hŒ™The payload is optional, and the pointer can be NULL if not required by
the type. The payload is plen in size, and plen can be zero for an empty
payload.”h]”hŒ™The payload is optional, and the pointer can be NULL if not required by
the type. The payload is plen in size, and plen can be zero for an empty
payload.”…””}”(hjî
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M’hj¤
  ubhÌ)”}”(hŒˆA new keyring can be generated by setting type "keyring", the keyring name
as the description (or NULL) and setting the payload to NULL.”h]”hŒŒA new keyring can be generated by setting type â€œkeyringâ€, the keyring name
as the description (or NULL) and setting the payload to NULL.”…””}”(hjü
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M–hj¤
  ubhÌ)”}”(hŒ×User defined keys can be created by specifying type "user". It is
recommended that a user defined key's description by prefixed with a type
ID and a colon, such as "krb5tgt:" for a Kerberos 5 ticket granting
ticket.”h]”hŒáUser defined keys can be created by specifying type â€œuserâ€. It is
recommended that a user defined keyâ€™s description by prefixed with a type
ID and a colon, such as â€œkrb5tgt:â€ for a Kerberos 5 ticket granting
ticket.”…””}”(hj
  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M™hj¤
  ubhÌ)”}”(hŒmAny other type must have been registered with the kernel in advance by a
kernel service such as a filesystem.”h]”hŒmAny other type must have been registered with the kernel in advance by a
kernel service such as a filesystem.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mžhj¤
  ubhÌ)”}”(hŒ;The ID of the new or updated key is returned if successful.”h]”hŒ;The ID of the new or updated key is returned if successful.”…””}”(hj&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¡hj¤
  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¡
  ubj*  )”}”(hX„  Search the process's keyrings for a key, potentially calling out to
userspace to create it::

   key_serial_t request_key(const char *type, const char *description,
                            const char *callout_info,
                            key_serial_t dest_keyring);

This function searches all the process's keyrings in the order thread,
process, session for a matching key. This works very much like
KEYCTL_SEARCH, including the optional attachment of the discovered key to
a keyring.

If a key cannot be found, and if callout_info is not NULL, then
/sbin/request-key will be invoked in an attempt to obtain a key. The
callout_info string will be passed as an argument to the program.

To link a key into the destination keyring the key must grant link
permission on the key to the caller and the keyring must grant write
permission.

See also Documentation/security/keys/request-key.rst.

”h]”(hÌ)”}”(hŒ\Search the process's keyrings for a key, potentially calling out to
userspace to create it::”h]”hŒ]Search the processâ€™s keyrings for a key, potentially calling out to
userspace to create it:”…””}”(hj>  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¤hj:  ubjC	  )”}”(hŒ«key_serial_t request_key(const char *type, const char *description,
                         const char *callout_info,
                         key_serial_t dest_keyring);”h]”hŒ«key_serial_t request_key(const char *type, const char *description,
                         const char *callout_info,
                         key_serial_t dest_keyring);”…””}”hjL  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M§hj:  ubhÌ)”}”(hŒÚThis function searches all the process's keyrings in the order thread,
process, session for a matching key. This works very much like
KEYCTL_SEARCH, including the optional attachment of the discovered key to
a keyring.”h]”hŒÜThis function searches all the processâ€™s keyrings in the order thread,
process, session for a matching key. This works very much like
KEYCTL_SEARCH, including the optional attachment of the discovered key to
a keyring.”…””}”(hjZ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M«hj:  ubhÌ)”}”(hŒÆIf a key cannot be found, and if callout_info is not NULL, then
/sbin/request-key will be invoked in an attempt to obtain a key. The
callout_info string will be passed as an argument to the program.”h]”hŒÆIf a key cannot be found, and if callout_info is not NULL, then
/sbin/request-key will be invoked in an attempt to obtain a key. The
callout_info string will be passed as an argument to the program.”…””}”(hjh  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M°hj:  ubhÌ)”}”(hŒ“To link a key into the destination keyring the key must grant link
permission on the key to the caller and the keyring must grant write
permission.”h]”hŒ“To link a key into the destination keyring the key must grant link
permission on the key to the caller and the keyring must grant write
permission.”…””}”(hjv  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M´hj:  ubhÌ)”}”(hŒ5See also Documentation/security/keys/request-key.rst.”h]”hŒ5See also Documentation/security/keys/request-key.rst.”…””}”(hj„  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¸hj:  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¡
  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´M{hj
  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M{hjT
  h²hubhÌ)”}”(hŒ!The keyctl syscall functions are:”h]”hŒ!The keyctl syscall functions are:”…””}”(hj¤  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M»hjT
  h²hubhø)”}”(hXœc  *  Map a special key ID to a real key ID for this process::

      key_serial_t keyctl(KEYCTL_GET_KEYRING_ID, key_serial_t id,
                          int create);

   The special key specified by "id" is looked up (with the key being created
   if necessary) and the ID of the key or keyring thus found is returned if
   it exists.

   If the key does not yet exist, the key will be created if "create" is
   non-zero; and the error ENOKEY will be returned if "create" is zero.


*  Replace the session keyring this process subscribes to with a new one::

      key_serial_t keyctl(KEYCTL_JOIN_SESSION_KEYRING, const char *name);

   If name is NULL, an anonymous keyring is created attached to the process
   as its session keyring, displacing the old session keyring.

   If name is not NULL, if a keyring of that name exists, the process
   attempts to attach it as the session keyring, returning an error if that
   is not permitted; otherwise a new keyring of that name is created and
   attached as the session keyring.

   To attach to a named keyring, the keyring must have search permission for
   the process's ownership.

   The ID of the new session keyring is returned if successful.


*  Update the specified key::

      long keyctl(KEYCTL_UPDATE, key_serial_t key, const void *payload,
                  size_t plen);

   This will try to update the specified key with the given payload, or it
   will return error EOPNOTSUPP if that function is not supported by the key
   type. The process must also have permission to write to the key to be able
   to update it.

   The payload is of length plen, and may be absent or empty as for
   add_key().


*  Revoke a key::

      long keyctl(KEYCTL_REVOKE, key_serial_t key);

   This makes a key unavailable for further operations. Further attempts to
   use the key will be met with error EKEYREVOKED, and the key will no longer
   be findable.


*  Change the ownership of a key::

      long keyctl(KEYCTL_CHOWN, key_serial_t key, uid_t uid, gid_t gid);

   This function permits a key's owner and group ID to be changed. Either one
   of uid or gid can be set to -1 to suppress that change.

   Only the superuser can change a key's owner to something other than the
   key's current owner. Similarly, only the superuser can change a key's
   group ID to something other than the calling process's group ID or one of
   its group list members.


*  Change the permissions mask on a key::

      long keyctl(KEYCTL_SETPERM, key_serial_t key, key_perm_t perm);

   This function permits the owner of a key or the superuser to change the
   permissions mask on a key.

   Only bits the available bits are permitted; if any other bits are set,
   error EINVAL will be returned.


*  Describe a key::

      long keyctl(KEYCTL_DESCRIBE, key_serial_t key, char *buffer,
                  size_t buflen);

   This function returns a summary of the key's attributes (but not its
   payload data) as a string in the buffer provided.

   Unless there's an error, it always returns the amount of data it could
   produce, even if that's too big for the buffer, but it won't copy more
   than requested to userspace. If the buffer pointer is NULL then no copy
   will take place.

   A process must have view permission on the key for this function to be
   successful.

   If successful, a string is placed in the buffer in the following format::

      <type>;<uid>;<gid>;<perm>;<description>

   Where type and description are strings, uid and gid are decimal, and perm
   is hexadecimal. A NUL character is included at the end of the string if
   the buffer is sufficiently big.

   This can be parsed with::

      sscanf(buffer, "%[^;];%d;%d;%o;%s", type, &uid, &gid, &mode, desc);


*  Clear out a keyring::

      long keyctl(KEYCTL_CLEAR, key_serial_t keyring);

   This function clears the list of keys attached to a keyring. The calling
   process must have write permission on the keyring, and it must be a
   keyring (or else error ENOTDIR will result).

   This function can also be used to clear special kernel keyrings if they
   are appropriately marked if the user has CAP_SYS_ADMIN capability.  The
   DNS resolver cache keyring is an example of this.


*  Link a key into a keyring::

      long keyctl(KEYCTL_LINK, key_serial_t keyring, key_serial_t key);

   This function creates a link from the keyring to the key. The process must
   have write permission on the keyring and must have link permission on the
   key.

   Should the keyring not be a keyring, error ENOTDIR will result; and if the
   keyring is full, error ENFILE will result.

   The link procedure checks the nesting of the keyrings, returning ELOOP if
   it appears too deep or EDEADLK if the link would introduce a cycle.

   Any links within the keyring to keys that match the new key in terms of
   type and description will be discarded from the keyring as the new one is
   added.


*  Move a key from one keyring to another::

      long keyctl(KEYCTL_MOVE,
                  key_serial_t id,
                  key_serial_t from_ring_id,
                  key_serial_t to_ring_id,
                  unsigned int flags);

   Move the key specified by "id" from the keyring specified by
   "from_ring_id" to the keyring specified by "to_ring_id".  If the two
   keyrings are the same, nothing is done.

   "flags" can have KEYCTL_MOVE_EXCL set in it to cause the operation to fail
   with EEXIST if a matching key exists in the destination keyring, otherwise
   such a key will be replaced.

   A process must have link permission on the key for this function to be
   successful and write permission on both keyrings.  Any errors that can
   occur from KEYCTL_LINK also apply on the destination keyring here.


*  Unlink a key or keyring from another keyring::

      long keyctl(KEYCTL_UNLINK, key_serial_t keyring, key_serial_t key);

   This function looks through the keyring for the first link to the
   specified key, and removes it if found. Subsequent links to that key are
   ignored. The process must have write permission on the keyring.

   If the keyring is not a keyring, error ENOTDIR will result; and if the key
   is not present, error ENOENT will be the result.


*  Search a keyring tree for a key::

      key_serial_t keyctl(KEYCTL_SEARCH, key_serial_t keyring,
                          const char *type, const char *description,
                          key_serial_t dest_keyring);

   This searches the keyring tree headed by the specified keyring until a key
   is found that matches the type and description criteria. Each keyring is
   checked for keys before recursion into its children occurs.

   The process must have search permission on the top level keyring, or else
   error EACCES will result. Only keyrings that the process has search
   permission on will be recursed into, and only keys and keyrings for which
   a process has search permission can be matched. If the specified keyring
   is not a keyring, ENOTDIR will result.

   If the search succeeds, the function will attempt to link the found key
   into the destination keyring if one is supplied (non-zero ID). All the
   constraints applicable to KEYCTL_LINK apply in this case too.

   Error ENOKEY, EKEYREVOKED or EKEYEXPIRED will be returned if the search
   fails. On success, the resulting key ID will be returned.


*  Read the payload data from a key::

      long keyctl(KEYCTL_READ, key_serial_t keyring, char *buffer,
                  size_t buflen);

   This function attempts to read the payload data from the specified key
   into the buffer. The process must have read permission on the key to
   succeed.

   The returned data will be processed for presentation by the key type. For
   instance, a keyring will return an array of key_serial_t entries
   representing the IDs of all the keys to which it is subscribed. The user
   defined key type will return its data as is. If a key type does not
   implement this function, error EOPNOTSUPP will result.

   If the specified buffer is too small, then the size of the buffer required
   will be returned.  Note that in this case, the contents of the buffer may
   have been overwritten in some undefined way.

   Otherwise, on success, the function will return the amount of data copied
   into the buffer.

*  Instantiate a partially constructed key::

      long keyctl(KEYCTL_INSTANTIATE, key_serial_t key,
                  const void *payload, size_t plen,
                  key_serial_t keyring);
      long keyctl(KEYCTL_INSTANTIATE_IOV, key_serial_t key,
                  const struct iovec *payload_iov, unsigned ioc,
                  key_serial_t keyring);

   If the kernel calls back to userspace to complete the instantiation of a
   key, userspace should use this call to supply data for the key before the
   invoked process returns, or else the key will be marked negative
   automatically.

   The process must have write access on the key to be able to instantiate
   it, and the key must be uninstantiated.

   If a keyring is specified (non-zero), the key will also be linked into
   that keyring, however all the constraints applying in KEYCTL_LINK apply in
   this case too.

   The payload and plen arguments describe the payload data as for add_key().

   The payload_iov and ioc arguments describe the payload data in an iovec
   array instead of a single buffer.


*  Negatively instantiate a partially constructed key::

      long keyctl(KEYCTL_NEGATE, key_serial_t key,
                  unsigned timeout, key_serial_t keyring);
      long keyctl(KEYCTL_REJECT, key_serial_t key,
                  unsigned timeout, unsigned error, key_serial_t keyring);

   If the kernel calls back to userspace to complete the instantiation of a
   key, userspace should use this call mark the key as negative before the
   invoked process returns if it is unable to fulfill the request.

   The process must have write access on the key to be able to instantiate
   it, and the key must be uninstantiated.

   If a keyring is specified (non-zero), the key will also be linked into
   that keyring, however all the constraints applying in KEYCTL_LINK apply in
   this case too.

   If the key is rejected, future searches for it will return the specified
   error code until the rejected key expires.  Negating the key is the same
   as rejecting the key with ENOKEY as the error code.


*  Set the default request-key destination keyring::

      long keyctl(KEYCTL_SET_REQKEY_KEYRING, int reqkey_defl);

   This sets the default keyring to which implicitly requested keys will be
   attached for this thread. reqkey_defl should be one of these constants::

      CONSTANT                                VALUE   NEW DEFAULT KEYRING
      ======================================  ======  =======================
      KEY_REQKEY_DEFL_NO_CHANGE               -1      No change
      KEY_REQKEY_DEFL_DEFAULT                 0       Default[1]
      KEY_REQKEY_DEFL_THREAD_KEYRING          1       Thread keyring
      KEY_REQKEY_DEFL_PROCESS_KEYRING         2       Process keyring
      KEY_REQKEY_DEFL_SESSION_KEYRING         3       Session keyring
      KEY_REQKEY_DEFL_USER_KEYRING            4       User keyring
      KEY_REQKEY_DEFL_USER_SESSION_KEYRING    5       User session keyring
      KEY_REQKEY_DEFL_GROUP_KEYRING           6       Group keyring

   The old default will be returned if successful and error EINVAL will be
   returned if reqkey_defl is not one of the above values.

   The default keyring can be overridden by the keyring indicated to the
   request_key() system call.

   Note that this setting is inherited across fork/exec.

   [1] The default is: the thread keyring if there is one, otherwise
   the process keyring if there is one, otherwise the session keyring if
   there is one, otherwise the user default session keyring.


*  Set the timeout on a key::

      long keyctl(KEYCTL_SET_TIMEOUT, key_serial_t key, unsigned timeout);

   This sets or clears the timeout on a key. The timeout can be 0 to clear
   the timeout or a number of seconds to set the expiry time that far into
   the future.

   The process must have attribute modification access on a key to set its
   timeout. Timeouts may not be set with this function on negative, revoked
   or expired keys.


*  Assume the authority granted to instantiate a key::

      long keyctl(KEYCTL_ASSUME_AUTHORITY, key_serial_t key);

   This assumes or divests the authority required to instantiate the
   specified key. Authority can only be assumed if the thread has the
   authorisation key associated with the specified key in its keyrings
   somewhere.

   Once authority is assumed, searches for keys will also search the
   requester's keyrings using the requester's security label, UID, GID and
   groups.

   If the requested authority is unavailable, error EPERM will be returned,
   likewise if the authority has been revoked because the target key is
   already instantiated.

   If the specified key is 0, then any assumed authority will be divested.

   The assumed authoritative key is inherited across fork and exec.


*  Get the LSM security context attached to a key::

      long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer,
                  size_t buflen)

   This function returns a string that represents the LSM security context
   attached to a key in the buffer provided.

   Unless there's an error, it always returns the amount of data it could
   produce, even if that's too big for the buffer, but it won't copy more
   than requested to userspace. If the buffer pointer is NULL then no copy
   will take place.

   A NUL character is included at the end of the string if the buffer is
   sufficiently big.  This is included in the returned count.  If no LSM is
   in force then an empty string will be returned.

   A process must have view permission on the key for this function to be
   successful.


*  Install the calling process's session keyring on its parent::

      long keyctl(KEYCTL_SESSION_TO_PARENT);

   This functions attempts to install the calling process's session keyring
   on to the calling process's parent, replacing the parent's current session
   keyring.

   The calling process must have the same ownership as its parent, the
   keyring must have the same ownership as the calling process, the calling
   process must have LINK permission on the keyring and the active LSM module
   mustn't deny permission, otherwise error EPERM will be returned.

   Error ENOMEM will be returned if there was insufficient memory to complete
   the operation, otherwise 0 will be returned to indicate success.

   The keyring will be replaced next time the parent process leaves the
   kernel and resumes executing userspace.


*  Invalidate a key::

      long keyctl(KEYCTL_INVALIDATE, key_serial_t key);

   This function marks a key as being invalidated and then wakes up the
   garbage collector.  The garbage collector immediately removes invalidated
   keys from all keyrings and deletes the key when its reference count
   reaches zero.

   Keys that are marked invalidated become invisible to normal key operations
   immediately, though they are still visible in /proc/keys until deleted
   (they're marked with an 'i' flag).

   A process must have search permission on the key for this function to be
   successful.

*  Compute a Diffie-Hellman shared secret or public key::

      long keyctl(KEYCTL_DH_COMPUTE, struct keyctl_dh_params *params,
                  char *buffer, size_t buflen, struct keyctl_kdf_params *kdf);

   The params struct contains serial numbers for three keys::

       - The prime, p, known to both parties
       - The local private key
       - The base integer, which is either a shared generator or the
         remote public key

   The value computed is::

      result = base ^ private (mod prime)

   If the base is the shared generator, the result is the local
   public key.  If the base is the remote public key, the result is
   the shared secret.

   If the parameter kdf is NULL, the following applies:

       - The buffer length must be at least the length of the prime, or zero.

       - If the buffer length is nonzero, the length of the result is
         returned when it is successfully calculated and copied in to the
         buffer. When the buffer length is zero, the minimum required
         buffer length is returned.

   The kdf parameter allows the caller to apply a key derivation function
   (KDF) on the Diffie-Hellman computation where only the result
   of the KDF is returned to the caller. The KDF is characterized with
   struct keyctl_kdf_params as follows:

       - ``char *hashname`` specifies the NUL terminated string identifying
         the hash used from the kernel crypto API and applied for the KDF
         operation. The KDF implementation complies with SP800-56A as well
         as with SP800-108 (the counter KDF).

       - ``char *otherinfo`` specifies the OtherInfo data as documented in
         SP800-56A section 5.8.1.2. The length of the buffer is given with
         otherinfolen. The format of OtherInfo is defined by the caller.
         The otherinfo pointer may be NULL if no OtherInfo shall be used.

   This function will return error EOPNOTSUPP if the key type is not
   supported, error ENOKEY if the key could not be found, or error
   EACCES if the key is not readable by the caller. In addition, the
   function will return EMSGSIZE when the parameter kdf is non-NULL
   and either the buffer length or the OtherInfo length exceeds the
   allowed length.


*  Restrict keyring linkage::

      long keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring,
                  const char *type, const char *restriction);

   An existing keyring can restrict linkage of additional keys by evaluating
   the contents of the key according to a restriction scheme.

   "keyring" is the key ID for an existing keyring to apply a restriction
   to. It may be empty or may already have keys linked. Existing linked keys
   will remain in the keyring even if the new restriction would reject them.

   "type" is a registered key type.

   "restriction" is a string describing how key linkage is to be restricted.
   The format varies depending on the key type, and the string is passed to
   the lookup_restriction() function for the requested type.  It may specify
   a method and relevant data for the restriction such as signature
   verification or constraints on key payload. If the requested key type is
   later unregistered, no keys may be added to the keyring after the key type
   is removed.

   To apply a keyring restriction the process must have Set Attribute
   permission and the keyring must not be previously restricted.

   One application of restricted keyrings is to verify X.509 certificate
   chains or individual certificate signatures using the asymmetric key type.
   See Documentation/crypto/asymmetric-keys.rst for specific restrictions
   applicable to the asymmetric key type.


*  Query an asymmetric key::

      long keyctl(KEYCTL_PKEY_QUERY,
                  key_serial_t key_id, unsigned long reserved,
                  const char *params,
                  struct keyctl_pkey_query *info);

   Get information about an asymmetric key.  Specific algorithms and
   encodings may be queried by using the ``params`` argument.  This is a
   string containing a space- or tab-separated string of key-value pairs.
   Currently supported keys include ``enc`` and ``hash``.  The information
   is returned in the keyctl_pkey_query struct::

      __u32   supported_ops;
      __u32   key_size;
      __u16   max_data_size;
      __u16   max_sig_size;
      __u16   max_enc_size;
      __u16   max_dec_size;
      __u32   __spare[10];

   ``supported_ops`` contains a bit mask of flags indicating which ops are
   supported.  This is constructed from a bitwise-OR of::

      KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}

   ``key_size`` indicated the size of the key in bits.

   ``max_*_size`` indicate the maximum sizes in bytes of a blob of data to be
   signed, a signature blob, a blob to be encrypted and a blob to be
   decrypted.

   ``__spare[]`` must be set to 0.  This is intended for future use to hand
   over one or more passphrases needed unlock a key.

   If successful, 0 is returned.  If the key is not an asymmetric key,
   EOPNOTSUPP is returned.


*  Encrypt, decrypt, sign or verify a blob using an asymmetric key::

      long keyctl(KEYCTL_PKEY_ENCRYPT,
                  const struct keyctl_pkey_params *params,
                  const char *info,
                  const void *in,
                  void *out);

      long keyctl(KEYCTL_PKEY_DECRYPT,
                  const struct keyctl_pkey_params *params,
                  const char *info,
                  const void *in,
                  void *out);

      long keyctl(KEYCTL_PKEY_SIGN,
                  const struct keyctl_pkey_params *params,
                  const char *info,
                  const void *in,
                  void *out);

      long keyctl(KEYCTL_PKEY_VERIFY,
                  const struct keyctl_pkey_params *params,
                  const char *info,
                  const void *in,
                  const void *in2);

   Use an asymmetric key to perform a public-key cryptographic operation a
   blob of data.  For encryption and verification, the asymmetric key may
   only need the public parts to be available, but for decryption and signing
   the private parts are required also.

   The parameter block pointed to by params contains a number of integer
   values::

      __s32           key_id;
      __u32           in_len;
      __u32           out_len;
      __u32           in2_len;

   ``key_id`` is the ID of the asymmetric key to be used.  ``in_len`` and
   ``in2_len`` indicate the amount of data in the in and in2 buffers and
   ``out_len`` indicates the size of the out buffer as appropriate for the
   above operations.

   For a given operation, the in and out buffers are used as follows::

      Operation ID            in,in_len       out,out_len     in2,in2_len
      ======================= =============== =============== ===============
      KEYCTL_PKEY_ENCRYPT     Raw data        Encrypted data  -
      KEYCTL_PKEY_DECRYPT     Encrypted data  Raw data        -
      KEYCTL_PKEY_SIGN        Raw data        Signature       -
      KEYCTL_PKEY_VERIFY      Raw data        -               Signature

   ``info`` is a string of key=value pairs that supply supplementary
   information.  These include:

      ``enc=<encoding>`` The encoding of the encrypted/signature blob.  This
                      can be "pkcs1" for RSASSA-PKCS1-v1.5 or
                      RSAES-PKCS1-v1.5; "pss" for "RSASSA-PSS"; "oaep" for
                      "RSAES-OAEP".  If omitted or is "raw", the raw output
                      of the encryption function is specified.

      ``hash=<algo>`` If the data buffer contains the output of a hash
                      function and the encoding includes some indication of
                      which hash function was used, the hash function can be
                      specified with this, eg. "hash=sha256".

   The ``__spare[]`` space in the parameter block must be set to 0.  This is
   intended, amongst other things, to allow the passing of passphrases
   required to unlock a key.

   If successful, encrypt, decrypt and sign all return the amount of data
   written into the output buffer.  Verification returns 0 on success.


*  Watch a key or keyring for changes::

      long keyctl(KEYCTL_WATCH_KEY, key_serial_t key, int queue_fd,
                  const struct watch_notification_filter *filter);

   This will set or remove a watch for changes on the specified key or
   keyring.

   "key" is the ID of the key to be watched.

   "queue_fd" is a file descriptor referring to an open pipe which
   manages the buffer into which notifications will be delivered.

   "filter" is either NULL to remove a watch or a filter specification to
   indicate what events are required from the key.

   See Documentation/core-api/watch_queue.rst for more information.

   Note that only one watch may be emplaced for any particular { key,
   queue_fd } combination.

   Notification records look like::

      struct key_notification {
              struct watch_notification watch;
              __u32   key_id;
              __u32   aux;
      };

   In this, watch::type will be "WATCH_TYPE_KEY_NOTIFY" and subtype will be
   one of::

      NOTIFY_KEY_INSTANTIATED
      NOTIFY_KEY_UPDATED
      NOTIFY_KEY_LINKED
      NOTIFY_KEY_UNLINKED
      NOTIFY_KEY_CLEARED
      NOTIFY_KEY_REVOKED
      NOTIFY_KEY_INVALIDATED
      NOTIFY_KEY_SETATTR

   Where these indicate a key being instantiated/rejected, updated, a link
   being made in a keyring, a link being removed from a keyring, a keyring
   being cleared, a key being revoked, a key being invalidated or a key
   having one of its attributes changed (user, group, perm, timeout,
   restriction).

   If a watched key is deleted, a basic watch_notification will be issued
   with "type" set to WATCH_TYPE_META and "subtype" set to
   watch_meta_removal_notification.  The watchpoint ID will be set in the
   "info" field.

   This needs to be configured by enabling:

      "Provide key/keyring change notifications" (KEY_NOTIFICATIONS)

”h]”j%  )”}”(hhh]”(j*  )”}”(hXÊ  Map a special key ID to a real key ID for this process::

   key_serial_t keyctl(KEYCTL_GET_KEYRING_ID, key_serial_t id,
                       int create);

The special key specified by "id" is looked up (with the key being created
if necessary) and the ID of the key or keyring thus found is returned if
it exists.

If the key does not yet exist, the key will be created if "create" is
non-zero; and the error ENOKEY will be returned if "create" is zero.

”h]”(hÌ)”}”(hŒ8Map a special key ID to a real key ID for this process::”h]”hŒ7Map a special key ID to a real key ID for this process:”…””}”(hj½  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M½hj¹  ubjC	  )”}”(hŒ\key_serial_t keyctl(KEYCTL_GET_KEYRING_ID, key_serial_t id,
                    int create);”h]”hŒ\key_serial_t keyctl(KEYCTL_GET_KEYRING_ID, key_serial_t id,
                    int create);”…””}”hjË  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M¿hj¹  ubhÌ)”}”(hŒžThe special key specified by "id" is looked up (with the key being created
if necessary) and the ID of the key or keyring thus found is returned if
it exists.”h]”hŒ¢The special key specified by â€œidâ€ is looked up (with the key being created
if necessary) and the ID of the key or keyring thus found is returned if
it exists.”…””}”(hjÙ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÂhj¹  ubhÌ)”}”(hŒŠIf the key does not yet exist, the key will be created if "create" is
non-zero; and the error ENOKEY will be returned if "create" is zero.”h]”hŒ’If the key does not yet exist, the key will be created if â€œcreateâ€ is
non-zero; and the error ENOKEY will be returned if â€œcreateâ€ is zero.”…””}”(hjç  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÆhj¹  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX­  Replace the session keyring this process subscribes to with a new one::

   key_serial_t keyctl(KEYCTL_JOIN_SESSION_KEYRING, const char *name);

If name is NULL, an anonymous keyring is created attached to the process
as its session keyring, displacing the old session keyring.

If name is not NULL, if a keyring of that name exists, the process
attempts to attach it as the session keyring, returning an error if that
is not permitted; otherwise a new keyring of that name is created and
attached as the session keyring.

To attach to a named keyring, the keyring must have search permission for
the process's ownership.

The ID of the new session keyring is returned if successful.

”h]”(hÌ)”}”(hŒGReplace the session keyring this process subscribes to with a new one::”h]”hŒFReplace the session keyring this process subscribes to with a new one:”…””}”(hjÿ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÊhjû  ubjC	  )”}”(hŒCkey_serial_t keyctl(KEYCTL_JOIN_SESSION_KEYRING, const char *name);”h]”hŒCkey_serial_t keyctl(KEYCTL_JOIN_SESSION_KEYRING, const char *name);”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MÌhjû  ubhÌ)”}”(hŒ„If name is NULL, an anonymous keyring is created attached to the process
as its session keyring, displacing the old session keyring.”h]”hŒ„If name is NULL, an anonymous keyring is created attached to the process
as its session keyring, displacing the old session keyring.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÎhjû  ubhÌ)”}”(hŒòIf name is not NULL, if a keyring of that name exists, the process
attempts to attach it as the session keyring, returning an error if that
is not permitted; otherwise a new keyring of that name is created and
attached as the session keyring.”h]”hŒòIf name is not NULL, if a keyring of that name exists, the process
attempts to attach it as the session keyring, returning an error if that
is not permitted; otherwise a new keyring of that name is created and
attached as the session keyring.”…””}”(hj)  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÑhjû  ubhÌ)”}”(hŒbTo attach to a named keyring, the keyring must have search permission for
the process's ownership.”h]”hŒdTo attach to a named keyring, the keyring must have search permission for
the processâ€™s ownership.”…””}”(hj7  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÖhjû  ubhÌ)”}”(hŒ<The ID of the new session keyring is returned if successful.”h]”hŒ<The ID of the new session keyring is returned if successful.”…””}”(hjE  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÙhjû  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX¸  Update the specified key::

   long keyctl(KEYCTL_UPDATE, key_serial_t key, const void *payload,
               size_t plen);

This will try to update the specified key with the given payload, or it
will return error EOPNOTSUPP if that function is not supported by the key
type. The process must also have permission to write to the key to be able
to update it.

The payload is of length plen, and may be absent or empty as for
add_key().

”h]”(hÌ)”}”(hŒUpdate the specified key::”h]”hŒUpdate the specified key:”…””}”(hj]  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÜhjY  ubjC	  )”}”(hŒ[long keyctl(KEYCTL_UPDATE, key_serial_t key, const void *payload,
            size_t plen);”h]”hŒ[long keyctl(KEYCTL_UPDATE, key_serial_t key, const void *payload,
            size_t plen);”…””}”hjk  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MÞhjY  ubhÌ)”}”(hŒêThis will try to update the specified key with the given payload, or it
will return error EOPNOTSUPP if that function is not supported by the key
type. The process must also have permission to write to the key to be able
to update it.”h]”hŒêThis will try to update the specified key with the given payload, or it
will return error EOPNOTSUPP if that function is not supported by the key
type. The process must also have permission to write to the key to be able
to update it.”…””}”(hjy  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MáhjY  ubhÌ)”}”(hŒKThe payload is of length plen, and may be absent or empty as for
add_key().”h]”hŒKThe payload is of length plen, and may be absent or empty as for
add_key().”…””}”(hj‡  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MæhjY  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hŒäRevoke a key::

   long keyctl(KEYCTL_REVOKE, key_serial_t key);

This makes a key unavailable for further operations. Further attempts to
use the key will be met with error EKEYREVOKED, and the key will no longer
be findable.

”h]”(hÌ)”}”(hŒRevoke a key::”h]”hŒRevoke a key:”…””}”(hjŸ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mêhj›  ubjC	  )”}”(hŒ-long keyctl(KEYCTL_REVOKE, key_serial_t key);”h]”hŒ-long keyctl(KEYCTL_REVOKE, key_serial_t key);”…””}”hj­  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mìhj›  ubhÌ)”}”(hŒ This makes a key unavailable for further operations. Further attempts to
use the key will be met with error EKEYREVOKED, and the key will no longer
be findable.”h]”hŒ This makes a key unavailable for further operations. Further attempts to
use the key will be met with error EKEYREVOKED, and the key will no longer
be findable.”…””}”(hj»  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mîhj›  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXÝ  Change the ownership of a key::

   long keyctl(KEYCTL_CHOWN, key_serial_t key, uid_t uid, gid_t gid);

This function permits a key's owner and group ID to be changed. Either one
of uid or gid can be set to -1 to suppress that change.

Only the superuser can change a key's owner to something other than the
key's current owner. Similarly, only the superuser can change a key's
group ID to something other than the calling process's group ID or one of
its group list members.

”h]”(hÌ)”}”(hŒChange the ownership of a key::”h]”hŒChange the ownership of a key:”…””}”(hjÓ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MóhjÏ  ubjC	  )”}”(hŒBlong keyctl(KEYCTL_CHOWN, key_serial_t key, uid_t uid, gid_t gid);”h]”hŒBlong keyctl(KEYCTL_CHOWN, key_serial_t key, uid_t uid, gid_t gid);”…””}”hjá  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MõhjÏ  ubhÌ)”}”(hŒ‚This function permits a key's owner and group ID to be changed. Either one
of uid or gid can be set to -1 to suppress that change.”h]”hŒ„This function permits a keyâ€™s owner and group ID to be changed. Either one
of uid or gid can be set to -1 to suppress that change.”…””}”(hjï  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M÷hjÏ  ubhÌ)”}”(hŒïOnly the superuser can change a key's owner to something other than the
key's current owner. Similarly, only the superuser can change a key's
group ID to something other than the calling process's group ID or one of
its group list members.”h]”hŒ÷Only the superuser can change a keyâ€™s owner to something other than the
keyâ€™s current owner. Similarly, only the superuser can change a keyâ€™s
group ID to something other than the calling processâ€™s group ID or one of
its group list members.”…””}”(hjý  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MúhjÏ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX7  Change the permissions mask on a key::

   long keyctl(KEYCTL_SETPERM, key_serial_t key, key_perm_t perm);

This function permits the owner of a key or the superuser to change the
permissions mask on a key.

Only bits the available bits are permitted; if any other bits are set,
error EINVAL will be returned.

”h]”(hÌ)”}”(hŒ&Change the permissions mask on a key::”h]”hŒ%Change the permissions mask on a key:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M hj  ubjC	  )”}”(hŒ?long keyctl(KEYCTL_SETPERM, key_serial_t key, key_perm_t perm);”h]”hŒ?long keyctl(KEYCTL_SETPERM, key_serial_t key, key_perm_t perm);”…””}”hj#  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhj  ubhÌ)”}”(hŒbThis function permits the owner of a key or the superuser to change the
permissions mask on a key.”h]”hŒbThis function permits the owner of a key or the superuser to change the
permissions mask on a key.”…””}”(hj1  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj  ubhÌ)”}”(hŒeOnly bits the available bits are permitted; if any other bits are set,
error EINVAL will be returned.”h]”hŒeOnly bits the available bits are permitted; if any other bits are set,
error EINVAL will be returned.”…””}”(hj?  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX³  Describe a key::

   long keyctl(KEYCTL_DESCRIBE, key_serial_t key, char *buffer,
               size_t buflen);

This function returns a summary of the key's attributes (but not its
payload data) as a string in the buffer provided.

Unless there's an error, it always returns the amount of data it could
produce, even if that's too big for the buffer, but it won't copy more
than requested to userspace. If the buffer pointer is NULL then no copy
will take place.

A process must have view permission on the key for this function to be
successful.

If successful, a string is placed in the buffer in the following format::

   <type>;<uid>;<gid>;<perm>;<description>

Where type and description are strings, uid and gid are decimal, and perm
is hexadecimal. A NUL character is included at the end of the string if
the buffer is sufficiently big.

This can be parsed with::

   sscanf(buffer, "%[^;];%d;%d;%o;%s", type, &uid, &gid, &mode, desc);

”h]”(hÌ)”}”(hŒDescribe a key::”h]”hŒDescribe a key:”…””}”(hjW  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjS  ubjC	  )”}”(hŒXlong keyctl(KEYCTL_DESCRIBE, key_serial_t key, char *buffer,
            size_t buflen);”h]”hŒXlong keyctl(KEYCTL_DESCRIBE, key_serial_t key, char *buffer,
            size_t buflen);”…””}”hje  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MhjS  ubhÌ)”}”(hŒvThis function returns a summary of the key's attributes (but not its
payload data) as a string in the buffer provided.”h]”hŒxThis function returns a summary of the keyâ€™s attributes (but not its
payload data) as a string in the buffer provided.”…””}”(hjs  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjS  ubhÌ)”}”(hŒæUnless there's an error, it always returns the amount of data it could
produce, even if that's too big for the buffer, but it won't copy more
than requested to userspace. If the buffer pointer is NULL then no copy
will take place.”h]”hŒìUnless thereâ€™s an error, it always returns the amount of data it could
produce, even if thatâ€™s too big for the buffer, but it wonâ€™t copy more
than requested to userspace. If the buffer pointer is NULL then no copy
will take place.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjS  ubhÌ)”}”(hŒRA process must have view permission on the key for this function to be
successful.”h]”hŒRA process must have view permission on the key for this function to be
successful.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjS  ubhÌ)”}”(hŒIIf successful, a string is placed in the buffer in the following format::”h]”hŒHIf successful, a string is placed in the buffer in the following format:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjS  ubjC	  )”}”(hŒ'<type>;<uid>;<gid>;<perm>;<description>”h]”hŒ'<type>;<uid>;<gid>;<perm>;<description>”…””}”hj«  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MhjS  ubhÌ)”}”(hŒ±Where type and description are strings, uid and gid are decimal, and perm
is hexadecimal. A NUL character is included at the end of the string if
the buffer is sufficiently big.”h]”hŒ±Where type and description are strings, uid and gid are decimal, and perm
is hexadecimal. A NUL character is included at the end of the string if
the buffer is sufficiently big.”…””}”(hj¹  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjS  ubhÌ)”}”(hŒThis can be parsed with::”h]”hŒThis can be parsed with:”…””}”(hjÇ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M#hjS  ubjC	  )”}”(hŒCsscanf(buffer, "%[^;];%d;%d;%o;%s", type, &uid, &gid, &mode, desc);”h]”hŒCsscanf(buffer, "%[^;];%d;%d;%o;%s", type, &uid, &gid, &mode, desc);”…””}”hjÕ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M%hjS  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXÊ  Clear out a keyring::

   long keyctl(KEYCTL_CLEAR, key_serial_t keyring);

This function clears the list of keys attached to a keyring. The calling
process must have write permission on the keyring, and it must be a
keyring (or else error ENOTDIR will result).

This function can also be used to clear special kernel keyrings if they
are appropriately marked if the user has CAP_SYS_ADMIN capability.  The
DNS resolver cache keyring is an example of this.

”h]”(hÌ)”}”(hŒClear out a keyring::”h]”hŒClear out a keyring:”…””}”(hjí  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M(hjé  ubjC	  )”}”(hŒ0long keyctl(KEYCTL_CLEAR, key_serial_t keyring);”h]”hŒ0long keyctl(KEYCTL_CLEAR, key_serial_t keyring);”…””}”hjû  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M*hjé  ubhÌ)”}”(hŒ¹This function clears the list of keys attached to a keyring. The calling
process must have write permission on the keyring, and it must be a
keyring (or else error ENOTDIR will result).”h]”hŒ¹This function clears the list of keys attached to a keyring. The calling
process must have write permission on the keyring, and it must be a
keyring (or else error ENOTDIR will result).”…””}”(hj	  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M,hjé  ubhÌ)”}”(hŒÁThis function can also be used to clear special kernel keyrings if they
are appropriately marked if the user has CAP_SYS_ADMIN capability.  The
DNS resolver cache keyring is an example of this.”h]”hŒÁThis function can also be used to clear special kernel keyrings if they
are appropriately marked if the user has CAP_SYS_ADMIN capability.  The
DNS resolver cache keyring is an example of this.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M0hjé  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXž  Link a key into a keyring::

   long keyctl(KEYCTL_LINK, key_serial_t keyring, key_serial_t key);

This function creates a link from the keyring to the key. The process must
have write permission on the keyring and must have link permission on the
key.

Should the keyring not be a keyring, error ENOTDIR will result; and if the
keyring is full, error ENFILE will result.

The link procedure checks the nesting of the keyrings, returning ELOOP if
it appears too deep or EDEADLK if the link would introduce a cycle.

Any links within the keyring to keys that match the new key in terms of
type and description will be discarded from the keyring as the new one is
added.

”h]”(hÌ)”}”(hŒLink a key into a keyring::”h]”hŒLink a key into a keyring:”…””}”(hj/  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M5hj+  ubjC	  )”}”(hŒAlong keyctl(KEYCTL_LINK, key_serial_t keyring, key_serial_t key);”h]”hŒAlong keyctl(KEYCTL_LINK, key_serial_t keyring, key_serial_t key);”…””}”hj=  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M7hj+  ubhÌ)”}”(hŒ™This function creates a link from the keyring to the key. The process must
have write permission on the keyring and must have link permission on the
key.”h]”hŒ™This function creates a link from the keyring to the key. The process must
have write permission on the keyring and must have link permission on the
key.”…””}”(hjK  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M9hj+  ubhÌ)”}”(hŒuShould the keyring not be a keyring, error ENOTDIR will result; and if the
keyring is full, error ENFILE will result.”h]”hŒuShould the keyring not be a keyring, error ENOTDIR will result; and if the
keyring is full, error ENFILE will result.”…””}”(hjY  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M=hj+  ubhÌ)”}”(hŒThe link procedure checks the nesting of the keyrings, returning ELOOP if
it appears too deep or EDEADLK if the link would introduce a cycle.”h]”hŒThe link procedure checks the nesting of the keyrings, returning ELOOP if
it appears too deep or EDEADLK if the link would introduce a cycle.”…””}”(hjg  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M@hj+  ubhÌ)”}”(hŒ˜Any links within the keyring to keys that match the new key in terms of
type and description will be discarded from the keyring as the new one is
added.”h]”hŒ˜Any links within the keyring to keys that match the new key in terms of
type and description will be discarded from the keyring as the new one is
added.”…””}”(hju  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MChj+  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX  Move a key from one keyring to another::

   long keyctl(KEYCTL_MOVE,
               key_serial_t id,
               key_serial_t from_ring_id,
               key_serial_t to_ring_id,
               unsigned int flags);

Move the key specified by "id" from the keyring specified by
"from_ring_id" to the keyring specified by "to_ring_id".  If the two
keyrings are the same, nothing is done.

"flags" can have KEYCTL_MOVE_EXCL set in it to cause the operation to fail
with EEXIST if a matching key exists in the destination keyring, otherwise
such a key will be replaced.

A process must have link permission on the key for this function to be
successful and write permission on both keyrings.  Any errors that can
occur from KEYCTL_LINK also apply on the destination keyring here.

”h]”(hÌ)”}”(hŒ(Move a key from one keyring to another::”h]”hŒ'Move a key from one keyring to another:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MHhj‰  ubjC	  )”}”(hŒ¢long keyctl(KEYCTL_MOVE,
            key_serial_t id,
            key_serial_t from_ring_id,
            key_serial_t to_ring_id,
            unsigned int flags);”h]”hŒ¢long keyctl(KEYCTL_MOVE,
            key_serial_t id,
            key_serial_t from_ring_id,
            key_serial_t to_ring_id,
            unsigned int flags);”…””}”hj›  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MJhj‰  ubhÌ)”}”(hŒ©Move the key specified by "id" from the keyring specified by
"from_ring_id" to the keyring specified by "to_ring_id".  If the two
keyrings are the same, nothing is done.”h]”hŒµMove the key specified by â€œidâ€ from the keyring specified by
â€œfrom_ring_idâ€ to the keyring specified by â€œto_ring_idâ€.  If the two
keyrings are the same, nothing is done.”…””}”(hj©  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MPhj‰  ubhÌ)”}”(hŒ²"flags" can have KEYCTL_MOVE_EXCL set in it to cause the operation to fail
with EEXIST if a matching key exists in the destination keyring, otherwise
such a key will be replaced.”h]”hŒ¶â€œflagsâ€ can have KEYCTL_MOVE_EXCL set in it to cause the operation to fail
with EEXIST if a matching key exists in the destination keyring, otherwise
such a key will be replaced.”…””}”(hj·  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MThj‰  ubhÌ)”}”(hŒÐA process must have link permission on the key for this function to be
successful and write permission on both keyrings.  Any errors that can
occur from KEYCTL_LINK also apply on the destination keyring here.”h]”hŒÐA process must have link permission on the key for this function to be
successful and write permission on both keyrings.  Any errors that can
occur from KEYCTL_LINK also apply on the destination keyring here.”…””}”(hjÅ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MXhj‰  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXÁ  Unlink a key or keyring from another keyring::

   long keyctl(KEYCTL_UNLINK, key_serial_t keyring, key_serial_t key);

This function looks through the keyring for the first link to the
specified key, and removes it if found. Subsequent links to that key are
ignored. The process must have write permission on the keyring.

If the keyring is not a keyring, error ENOTDIR will result; and if the key
is not present, error ENOENT will be the result.

”h]”(hÌ)”}”(hŒ.Unlink a key or keyring from another keyring::”h]”hŒ-Unlink a key or keyring from another keyring:”…””}”(hjÝ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M]hjÙ  ubjC	  )”}”(hŒClong keyctl(KEYCTL_UNLINK, key_serial_t keyring, key_serial_t key);”h]”hŒClong keyctl(KEYCTL_UNLINK, key_serial_t keyring, key_serial_t key);”…””}”hjë  sbah}”(h]”h ]”h"]”•      h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M_hjÙ  ubhÌ)”}”(hŒÊThis function looks through the keyring for the first link to the
specified key, and removes it if found. Subsequent links to that key are
ignored. The process must have write permission on the keyring.”h]”hŒÊThis function looks through the keyring for the first link to the
specified key, and removes it if found. Subsequent links to that key are
ignored. The process must have write permission on the keyring.”…””}”(hjù  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MahjÙ  ubhÌ)”}”(hŒ{If the keyring is not a keyring, error ENOTDIR will result; and if the key
is not present, error ENOENT will be the result.”h]”hŒ{If the keyring is not a keyring, error ENOTDIR will result; and if the key
is not present, error ENOENT will be the result.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MehjÙ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX@  Search a keyring tree for a key::

   key_serial_t keyctl(KEYCTL_SEARCH, key_serial_t keyring,
                       const char *type, const char *description,
                       key_serial_t dest_keyring);

This searches the keyring tree headed by the specified keyring until a key
is found that matches the type and description criteria. Each keyring is
checked for keys before recursion into its children occurs.

The process must have search permission on the top level keyring, or else
error EACCES will result. Only keyrings that the process has search
permission on will be recursed into, and only keys and keyrings for which
a process has search permission can be matched. If the specified keyring
is not a keyring, ENOTDIR will result.

If the search succeeds, the function will attempt to link the found key
into the destination keyring if one is supplied (non-zero ID). All the
constraints applicable to KEYCTL_LINK apply in this case too.

Error ENOKEY, EKEYREVOKED or EKEYEXPIRED will be returned if the search
fails. On success, the resulting key ID will be returned.

”h]”(hÌ)”}”(hŒ!Search a keyring tree for a key::”h]”hŒ Search a keyring tree for a key:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mihj  ubjC	  )”}”(hŒ§key_serial_t keyctl(KEYCTL_SEARCH, key_serial_t keyring,
                    const char *type, const char *description,
                    key_serial_t dest_keyring);”h]”hŒ§key_serial_t keyctl(KEYCTL_SEARCH, key_serial_t keyring,
                    const char *type, const char *description,
                    key_serial_t dest_keyring);”…””}”hj-  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mkhj  ubhÌ)”}”(hŒÏThis searches the keyring tree headed by the specified keyring until a key
is found that matches the type and description criteria. Each keyring is
checked for keys before recursion into its children occurs.”h]”hŒÏThis searches the keyring tree headed by the specified keyring until a key
is found that matches the type and description criteria. Each keyring is
checked for keys before recursion into its children occurs.”…””}”(hj;  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mohj  ubhÌ)”}”(hXG  The process must have search permission on the top level keyring, or else
error EACCES will result. Only keyrings that the process has search
permission on will be recursed into, and only keys and keyrings for which
a process has search permission can be matched. If the specified keyring
is not a keyring, ENOTDIR will result.”h]”hXG  The process must have search permission on the top level keyring, or else
error EACCES will result. Only keyrings that the process has search
permission on will be recursed into, and only keys and keyrings for which
a process has search permission can be matched. If the specified keyring
is not a keyring, ENOTDIR will result.”…””}”(hjI  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mshj  ubhÌ)”}”(hŒÌIf the search succeeds, the function will attempt to link the found key
into the destination keyring if one is supplied (non-zero ID). All the
constraints applicable to KEYCTL_LINK apply in this case too.”h]”hŒÌIf the search succeeds, the function will attempt to link the found key
into the destination keyring if one is supplied (non-zero ID). All the
constraints applicable to KEYCTL_LINK apply in this case too.”…””}”(hjW  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Myhj  ubhÌ)”}”(hŒError ENOKEY, EKEYREVOKED or EKEYEXPIRED will be returned if the search
fails. On success, the resulting key ID will be returned.”h]”hŒError ENOKEY, EKEYREVOKED or EKEYEXPIRED will be returned if the search
fails. On success, the resulting key ID will be returned.”…””}”(hje  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M}hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXˆ  Read the payload data from a key::

   long keyctl(KEYCTL_READ, key_serial_t keyring, char *buffer,
               size_t buflen);

This function attempts to read the payload data from the specified key
into the buffer. The process must have read permission on the key to
succeed.

The returned data will be processed for presentation by the key type. For
instance, a keyring will return an array of key_serial_t entries
representing the IDs of all the keys to which it is subscribed. The user
defined key type will return its data as is. If a key type does not
implement this function, error EOPNOTSUPP will result.

If the specified buffer is too small, then the size of the buffer required
will be returned.  Note that in this case, the contents of the buffer may
have been overwritten in some undefined way.

Otherwise, on success, the function will return the amount of data copied
into the buffer.
”h]”(hÌ)”}”(hŒ"Read the payload data from a key::”h]”hŒ!Read the payload data from a key:”…””}”(hj}  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjy  ubjC	  )”}”(hŒXlong keyctl(KEYCTL_READ, key_serial_t keyring, char *buffer,
            size_t buflen);”h]”hŒXlong keyctl(KEYCTL_READ, key_serial_t keyring, char *buffer,
            size_t buflen);”…””}”hj‹  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mƒhjy  ubhÌ)”}”(hŒ”This function attempts to read the payload data from the specified key
into the buffer. The process must have read permission on the key to
succeed.”h]”hŒ”This function attempts to read the payload data from the specified key
into the buffer. The process must have read permission on the key to
succeed.”…””}”(hj™  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M†hjy  ubhÌ)”}”(hXN  The returned data will be processed for presentation by the key type. For
instance, a keyring will return an array of key_serial_t entries
representing the IDs of all the keys to which it is subscribed. The user
defined key type will return its data as is. If a key type does not
implement this function, error EOPNOTSUPP will result.”h]”hXN  The returned data will be processed for presentation by the key type. For
instance, a keyring will return an array of key_serial_t entries
representing the IDs of all the keys to which it is subscribed. The user
defined key type will return its data as is. If a key type does not
implement this function, error EOPNOTSUPP will result.”…””}”(hj§  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MŠhjy  ubhÌ)”}”(hŒÁIf the specified buffer is too small, then the size of the buffer required
will be returned.  Note that in this case, the contents of the buffer may
have been overwritten in some undefined way.”h]”hŒÁIf the specified buffer is too small, then the size of the buffer required
will be returned.  Note that in this case, the contents of the buffer may
have been overwritten in some undefined way.”…””}”(hjµ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjy  ubhÌ)”}”(hŒZOtherwise, on success, the function will return the amount of data copied
into the buffer.”h]”hŒZOtherwise, on success, the function will return the amount of data copied
into the buffer.”…””}”(hjÃ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M”hjy  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX  Instantiate a partially constructed key::

   long keyctl(KEYCTL_INSTANTIATE, key_serial_t key,
               const void *payload, size_t plen,
               key_serial_t keyring);
   long keyctl(KEYCTL_INSTANTIATE_IOV, key_serial_t key,
               const struct iovec *payload_iov, unsigned ioc,
               key_serial_t keyring);

If the kernel calls back to userspace to complete the instantiation of a
key, userspace should use this call to supply data for the key before the
invoked process returns, or else the key will be marked negative
automatically.

The process must have write access on the key to be able to instantiate
it, and the key must be uninstantiated.

If a keyring is specified (non-zero), the key will also be linked into
that keyring, however all the constraints applying in KEYCTL_LINK apply in
this case too.

The payload and plen arguments describe the payload data as for add_key().

The payload_iov and ioc arguments describe the payload data in an iovec
array instead of a single buffer.

”h]”(hÌ)”}”(hŒ)Instantiate a partially constructed key::”h]”hŒ(Instantiate a partially constructed key:”…””}”(hjÛ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M—hj×  ubjC	  )”}”(hX  long keyctl(KEYCTL_INSTANTIATE, key_serial_t key,
            const void *payload, size_t plen,
            key_serial_t keyring);
long keyctl(KEYCTL_INSTANTIATE_IOV, key_serial_t key,
            const struct iovec *payload_iov, unsigned ioc,
            key_serial_t keyring);”h]”hX  long keyctl(KEYCTL_INSTANTIATE, key_serial_t key,
            const void *payload, size_t plen,
            key_serial_t keyring);
long keyctl(KEYCTL_INSTANTIATE_IOV, key_serial_t key,
            const struct iovec *payload_iov, unsigned ioc,
            key_serial_t keyring);”…””}”hjé  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M™hj×  ubhÌ)”}”(hŒâIf the kernel calls back to userspace to complete the instantiation of a
key, userspace should use this call to supply data for the key before the
invoked process returns, or else the key will be marked negative
automatically.”h]”hŒâIf the kernel calls back to userspace to complete the instantiation of a
key, userspace should use this call to supply data for the key before the
invoked process returns, or else the key will be marked negative
automatically.”…””}”(hj÷  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M hj×  ubhÌ)”}”(hŒoThe process must have write access on the key to be able to instantiate
it, and the key must be uninstantiated.”h]”hŒoThe process must have write access on the key to be able to instantiate
it, and the key must be uninstantiated.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¥hj×  ubhÌ)”}”(hŒ If a keyring is specified (non-zero), the key will also be linked into
that keyring, however all the constraints applying in KEYCTL_LINK apply in
this case too.”h]”hŒ If a keyring is specified (non-zero), the key will also be linked into
that keyring, however all the constraints applying in KEYCTL_LINK apply in
this case too.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¨hj×  ubhÌ)”}”(hŒJThe payload and plen arguments describe the payload data as for add_key().”h]”hŒJThe payload and plen arguments describe the payload data as for add_key().”…””}”(hj!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¬hj×  ubhÌ)”}”(hŒiThe payload_iov and ioc arguments describe the payload data in an iovec
array instead of a single buffer.”h]”hŒiThe payload_iov and ioc arguments describe the payload data in an iovec
array instead of a single buffer.”…””}”(hj/  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M®hj×  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXÃ  Negatively instantiate a partially constructed key::

   long keyctl(KEYCTL_NEGATE, key_serial_t key,
               unsigned timeout, key_serial_t keyring);
   long keyctl(KEYCTL_REJECT, key_serial_t key,
               unsigned timeout, unsigned error, key_serial_t keyring);

If the kernel calls back to userspace to complete the instantiation of a
key, userspace should use this call mark the key as negative before the
invoked process returns if it is unable to fulfill the request.

The process must have write access on the key to be able to instantiate
it, and the key must be uninstantiated.

If a keyring is specified (non-zero), the key will also be linked into
that keyring, however all the constraints applying in KEYCTL_LINK apply in
this case too.

If the key is rejected, future searches for it will return the specified
error code until the rejected key expires.  Negating the key is the same
as rejecting the key with ENOKEY as the error code.

”h]”(hÌ)”}”(hŒ4Negatively instantiate a partially constructed key::”h]”hŒ3Negatively instantiate a partially constructed key:”…””}”(hjG  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M²hjC  ubjC	  )”}”(hŒÓlong keyctl(KEYCTL_NEGATE, key_serial_t key,
            unsigned timeout, key_serial_t keyring);
long keyctl(KEYCTL_REJECT, key_serial_t key,
            unsigned timeout, unsigned error, key_serial_t keyring);”h]”hŒÓlong keyctl(KEYCTL_NEGATE, key_serial_t key,
            unsigned timeout, key_serial_t keyring);
long keyctl(KEYCTL_REJECT, key_serial_t key,
            unsigned timeout, unsigned error, key_serial_t keyring);”…””}”hjU  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M´hjC  ubhÌ)”}”(hŒÐIf the kernel calls back to userspace to complete the instantiation of a
key, userspace should use this call mark the key as negative before the
invoked process returns if it is unable to fulfill the request.”h]”hŒÐIf the kernel calls back to userspace to complete the instantiation of a
key, userspace should use this call mark the key as negative before the
invoked process returns if it is unable to fulfill the request.”…””}”(hjc  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¹hjC  ubhÌ)”}”(hŒoThe process must have write access on the key to be able to instantiate
it, and the key must be uninstantiated.”h]”hŒoThe process must have write access on the key to be able to instantiate
it, and the key must be uninstantiated.”…””}”(hjq  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M½hjC  ubhÌ)”}”(hŒ If a keyring is specified (non-zero), the key will also be linked into
that keyring, however all the constraints applying in KEYCTL_LINK apply in
this case too.”h]”hŒ If a keyring is specified (non-zero), the key will also be linked into
that keyring, however all the constraints applying in KEYCTL_LINK apply in
this case too.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÀhjC  ubhÌ)”}”(hŒÅIf the key is rejected, future searches for it will return the specified
error code until the rejected key expires.  Negating the key is the same
as rejecting the key with ENOKEY as the error code.”h]”hŒÅIf the key is rejected, future searches for it will return the specified
error code until the rejected key expires.  Negating the key is the same
as rejecting the key with ENOKEY as the error code.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÄhjC  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX  Set the default request-key destination keyring::

   long keyctl(KEYCTL_SET_REQKEY_KEYRING, int reqkey_defl);

This sets the default keyring to which implicitly requested keys will be
attached for this thread. reqkey_defl should be one of these constants::

   CONSTANT                                VALUE   NEW DEFAULT KEYRING
   ======================================  ======  =======================
   KEY_REQKEY_DEFL_NO_CHANGE               -1      No change
   KEY_REQKEY_DEFL_DEFAULT                 0       Default[1]
   KEY_REQKEY_DEFL_THREAD_KEYRING          1       Thread keyring
   KEY_REQKEY_DEFL_PROCESS_KEYRING         2       Process keyring
   KEY_REQKEY_DEFL_SESSION_KEYRING         3       Session keyring
   KEY_REQKEY_DEFL_USER_KEYRING            4       User keyring
   KEY_REQKEY_DEFL_USER_SESSION_KEYRING    5       User session keyring
   KEY_REQKEY_DEFL_GROUP_KEYRING           6       Group keyring

The old default will be returned if successful and error EINVAL will be
returned if reqkey_defl is not one of the above values.

The default keyring can be overridden by the keyring indicated to the
request_key() system call.

Note that this setting is inherited across fork/exec.

[1] The default is: the thread keyring if there is one, otherwise
the process keyring if there is one, otherwise the session keyring if
there is one, otherwise the user default session keyring.

”h]”(hÌ)”}”(hŒ1Set the default request-key destination keyring::”h]”hŒ0Set the default request-key destination keyring:”…””}”(hj¥  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÉhj¡  ubjC	  )”}”(hŒ8long keyctl(KEYCTL_SET_REQKEY_KEYRING, int reqkey_defl);”h]”hŒ8long keyctl(KEYCTL_SET_REQKEY_KEYRING, int reqkey_defl);”…””}”hj³  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MËhj¡  ubhÌ)”}”(hŒ‘This sets the default keyring to which implicitly requested keys will be
attached for this thread. reqkey_defl should be one of these constants::”h]”hŒThis sets the default keyring to which implicitly requested keys will be
attached for this thread. reqkey_defl should be one of these constants:”…””}”(hjÁ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÍhj¡  ubjC	  )”}”(hX  CONSTANT                                VALUE   NEW DEFAULT KEYRING
======================================  ======  =======================
KEY_REQKEY_DEFL_NO_CHANGE               -1      No change
KEY_REQKEY_DEFL_DEFAULT                 0       Default[1]
KEY_REQKEY_DEFL_THREAD_KEYRING          1       Thread keyring
KEY_REQKEY_DEFL_PROCESS_KEYRING         2       Process keyring
KEY_REQKEY_DEFL_SESSION_KEYRING         3       Session keyring
KEY_REQKEY_DEFL_USER_KEYRING            4       User keyring
KEY_REQKEY_DEFL_USER_SESSION_KEYRING    5       User session keyring
KEY_REQKEY_DEFL_GROUP_KEYRING           6       Group keyring”h]”hX  CONSTANT                                VALUE   NEW DEFAULT KEYRING
======================================  ======  =======================
KEY_REQKEY_DEFL_NO_CHANGE               -1      No change
KEY_REQKEY_DEFL_DEFAULT                 0       Default[1]
KEY_REQKEY_DEFL_THREAD_KEYRING          1       Thread keyring
KEY_REQKEY_DEFL_PROCESS_KEYRING         2       Process keyring
KEY_REQKEY_DEFL_SESSION_KEYRING         3       Session keyring
KEY_REQKEY_DEFL_USER_KEYRING            4       User keyring
KEY_REQKEY_DEFL_USER_SESSION_KEYRING    5       User session keyring
KEY_REQKEY_DEFL_GROUP_KEYRING           6       Group keyring”…””}”hjÏ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MÐhj¡  ubhÌ)”}”(hŒThe old default will be returned if successful and error EINVAL will be
returned if reqkey_defl is not one of the above values.”h]”hŒThe old default will be returned if successful and error EINVAL will be
returned if reqkey_defl is not one of the above values.”…””}”(hjÝ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÛhj¡  ubhÌ)”}”(hŒ`The default keyring can be overridden by the keyring indicated to the
request_key() system call.”h]”hŒ`The default keyring can be overridden by the keyring indicated to the
request_key() system call.”…””}”(hjë  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÞhj¡  ubhÌ)”}”(hŒ5Note that this setting is inherited across fork/exec.”h]”hŒ5Note that this setting is inherited across fork/exec.”…””}”(hjù  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Máhj¡  ubhÌ)”}”(hŒÁ[1] The default is: the thread keyring if there is one, otherwise
the process keyring if there is one, otherwise the session keyring if
there is one, otherwise the user default session keyring.”h]”hŒÁ[1] The default is: the thread keyring if there is one, otherwise
the process keyring if there is one, otherwise the session keyring if
there is one, otherwise the user default session keyring.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mãhj¡  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX¥  Set the timeout on a key::

   long keyctl(KEYCTL_SET_TIMEOUT, key_serial_t key, unsigned timeout);

This sets or clears the timeout on a key. The timeout can be 0 to clear
the timeout or a number of seconds to set the expiry time that far into
the future.

The process must have attribute modification access on a key to set its
timeout. Timeouts may not be set with this function on negative, revoked
or expired keys.

”h]”(hÌ)”}”(hŒSet the timeout on a key::”h]”hŒSet the timeout on a key:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mèhj  ubjC	  )”}”(hŒDlong keyctl(KEYCTL_SET_TIMEOUT, key_serial_t key, unsigned timeout);”h]”hŒDlong keyctl(KEYCTL_SET_TIMEOUT, key_serial_t key, unsigned timeout);”…””}”hj-  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mêhj  ubhÌ)”}”(hŒ›This sets or clears the timeout on a key. The timeout can be 0 to clear
the timeout or a number of seconds to set the expiry time that far into
the future.”h]”hŒ›This sets or clears the timeout on a key. The timeout can be 0 to clear
the timeout or a number of seconds to set the expiry time that far into
the future.”…””}”(hj;  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mìhj  ubhÌ)”}”(hŒ¡The process must have attribute modification access on a key to set its
timeout. Timeouts may not be set with this function on negative, revoked
or expired keys.”h]”hŒ¡The process must have attribute modification access on a key to set its
timeout. Timeouts may not be set with this function on negative, revoked
or expired keys.”…””}”(hjI  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mðhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX	  Assume the authority granted to instantiate a key::

   long keyctl(KEYCTL_ASSUME_AUTHORITY, key_serial_t key);

This assumes or divests the authority required to instantiate the
specified key. Authority can only be assumed if the thread has the
authorisation key associated with the specified key in its keyrings
somewhere.

Once authority is assumed, searches for keys will also search the
requester's keyrings using the requester's security label, UID, GID and
groups.

If the requested authority is unavailable, error EPERM will be returned,
likewise if the authority has been revoked because the target key is
already instantiated.

If the specified key is 0, then any assumed authority will be divested.

The assumed authoritative key is inherited across fork and exec.

”h]”(hÌ)”}”(hŒ3Assume the authority granted to instantiate a key::”h]”hŒ2Assume the authority granted to instantiate a key:”…””}”(hja  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mõhj]  ubjC	  )”}”(hŒ7long keyctl(KEYCTL_ASSUME_AUTHORITY, key_serial_t key);”h]”hŒ7long keyctl(KEYCTL_ASSUME_AUTHORITY, key_serial_t key);”…””}”hjo  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M÷hj]  ubhÌ)”}”(hŒÓThis assumes or divests the authority required to instantiate the
specified key. Authority can only be assumed if the thread has the
authorisation key associated with the specified key in its keyrings
somewhere.”h]”hŒÓThis assumes or divests the authority required to instantiate the
specified key. Authority can only be assumed if the thread has the
authorisation key associated with the specified key in its keyrings
somewhere.”…””}”(hj}  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mùhj]  ubhÌ)”}”(hŒ‘Once authority is assumed, searches for keys will also search the
requester's keyrings using the requester's security label, UID, GID and
groups.”h]”hŒ•Once authority is assumed, searches for keys will also search the
requesterâ€™s keyrings using the requesterâ€™s security label, UID, GID and
groups.”…””}”(hj‹  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mþhj]  ubhÌ)”}”(hŒ£If the requested authority is unavailable, error EPERM will be returned,
likewise if the authority has been revoked because the target key is
already instantiated.”h]”hŒ£If the requested authority is unavailable, error EPERM will be returned,
likewise if the authority has been revoked because the target key is
already instantiated.”…””}”(hj™  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj]  ubhÌ)”}”(hŒGIf the specified key is 0, then any assumed authority will be divested.”h]”hŒGIf the specified key is 0, then any assumed authority will be divested.”…””}”(hj§  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj]  ubhÌ)”}”(hŒ@The assumed authoritative key is inherited across fork and exec.”h]”hŒ@The assumed authoritative key is inherited across fork and exec.”…””}”(hjµ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj]  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX  Get the LSM security context attached to a key::

   long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer,
               size_t buflen)

This function returns a string that represents the LSM security context
attached to a key in the buffer provided.

Unless there's an error, it always returns the amount of data it could
produce, even if that's too big for the buffer, but it won't copy more
than requested to userspace. If the buffer pointer is NULL then no copy
will take place.

A NUL character is included at the end of the string if the buffer is
sufficiently big.  This is included in the returned count.  If no LSM is
in force then an empty string will be returned.

A process must have view permission on the key for this function to be
successful.

”h]”(hÌ)”}”(hŒ0Get the LSM security context attached to a key::”h]”hŒ/Get the LSM security context attached to a key:”…””}”(hjÍ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÉ  ubjC	  )”}”(hŒ[long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer,
            size_t buflen)”h]”hŒ[long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer,
            size_t buflen)”…””}”hjÛ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MhjÉ  ubhÌ)”}”(hŒqThis function returns a string that represents the LSM security context
attached to a key in the buffer provided.”h]”hŒqThis function returns a string that represents the LSM security context
attached to a key in the buffer provided.”…””}”(hjé  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÉ  ubhÌ)”}”(hŒæUnless there's an error, it always returns the amount of data it could
produce, even if that's too big for the buffer, but it won't copy more
than requested to userspace. If the buffer pointer is NULL then no copy
will take place.”h]”hŒìUnless thereâ€™s an error, it always returns the amount of data it could
produce, even if thatâ€™s too big for the buffer, but it wonâ€™t copy more
than requested to userspace. If the buffer pointer is NULL then no copy
will take place.”…””}”(hj÷  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÉ  ubhÌ)”}”(hŒ¾A NUL character is included at the end of the string if the buffer is
sufficiently big.  This is included in the returned count.  If no LSM is
in force then an empty string will be returned.”h]”hŒ¾A NUL character is included at the end of the string if the buffer is
sufficiently big.  This is included in the returned count.  If no LSM is
in force then an empty string will be returned.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÉ  ubhÌ)”}”(hŒRA process must have view permission on the key for this function to be
successful.”h]”hŒRA process must have view permission on the key for this function to be
successful.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÉ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX  Install the calling process's session keyring on its parent::

   long keyctl(KEYCTL_SESSION_TO_PARENT);

This functions attempts to install the calling process's session keyring
on to the calling process's parent, replacing the parent's current session
keyring.

The calling process must have the same ownership as its parent, the
keyring must have the same ownership as the calling process, the calling
process must have LINK permission on the keyring and the active LSM module
mustn't deny permission, otherwise error EPERM will be returned.

Error ENOMEM will be returned if there was insufficient memory to complete
the operation, otherwise 0 will be returned to indicate success.

The keyring will be replaced next time the parent process leaves the
kernel and resumes executing userspace.

”h]”(hÌ)”}”(hŒ=Install the calling process's session keyring on its parent::”h]”hŒ>Install the calling processâ€™s session keyring on its parent:”…””}”(hj+  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M hj'  ubjC	  )”}”(hŒ&long keyctl(KEYCTL_SESSION_TO_PARENT);”h]”hŒ&long keyctl(KEYCTL_SESSION_TO_PARENT);”…””}”hj9  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M"hj'  ubhÌ)”}”(hŒœThis functions attempts to install the calling process's session keyring
on to the calling process's parent, replacing the parent's current session
keyring.”h]”hŒ¢This functions attempts to install the calling processâ€™s session keyring
on to the calling processâ€™s parent, replacing the parentâ€™s current session
keyring.”…””}”(hjG  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M$hj'  ubhÌ)”}”(hX  The calling process must have the same ownership as its parent, the
keyring must have the same ownership as the calling process, the calling
process must have LINK permission on the keyring and the active LSM module
mustn't deny permission, otherwise error EPERM will be returned.”h]”hX  The calling process must have the same ownership as its parent, the
keyring must have the same ownership as the calling process, the calling
process must have LINK permission on the keyring and the active LSM module
mustnâ€™t deny permission, otherwise error EPERM will be returned.”…””}”(hjU  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M(hj'  ubhÌ)”}”(hŒ‹Error ENOMEM will be returned if there was insufficient memory to complete
the operation, otherwise 0 will be returned to indicate success.”h]”hŒ‹Error ENOMEM will be returned if there was insufficient memory to complete
the operation, otherwise 0 will be returned to indicate success.”…””}”(hjc  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M-hj'  ubhÌ)”}”(hŒlThe keyring will be replaced next time the parent process leaves the
kernel and resumes executing userspace.”h]”hŒlThe keyring will be replaced next time the parent process leaves the
kernel and resumes executing userspace.”…””}”(hjq  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M0hj'  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX7  Invalidate a key::

   long keyctl(KEYCTL_INVALIDATE, key_serial_t key);

This function marks a key as being invalidated and then wakes up the
garbage collector.  The garbage collector immediately removes invalidated
keys from all keyrings and deletes the key when its reference count
reaches zero.

Keys that are marked invalidated become invisible to normal key operations
immediately, though they are still visible in /proc/keys until deleted
(they're marked with an 'i' flag).

A process must have search permission on the key for this function to be
successful.
”h]”(hÌ)”}”(hŒInvalidate a key::”h]”hŒInvalidate a key:”…””}”(hj‰  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M4hj…  ubjC	  )”}”(hŒ1long keyctl(KEYCTL_INVALIDATE, key_serial_t key);”h]”hŒ1long keyctl(KEYCTL_INVALIDATE, key_serial_t key);”…””}”hj—  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M6hj…  ubhÌ)”}”(hŒàThis function marks a key as being invalidated and then wakes up the
garbage collector.  The garbage collector immediately removes invalidated
keys from all keyrings and deletes the key when its reference count
reaches zero.”h]”hŒàThis function marks a key as being invalidated and then wakes up the
garbage collector.  The garbage collector immediately removes invalidated
keys from all keyrings and deletes the key when its reference count
reaches zero.”…””}”(hj¥  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M8hj…  ubhÌ)”}”(hŒ´Keys that are marked invalidated become invisible to normal key operations
immediately, though they are still visible in /proc/keys until deleted
(they're marked with an 'i' flag).”h]”hŒºKeys that are marked invalidated become invisible to normal key operations
immediately, though they are still visible in /proc/keys until deleted
(theyâ€™re marked with an â€˜iâ€™ flag).”…””}”(hj³  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M=hj…  ubhÌ)”}”(hŒTA process must have search permission on the key for this function to be
successful.”h]”hŒTA process must have search permission on the key for this function to be
successful.”…””}”(hjÁ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MAhj…  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXQ  Compute a Diffie-Hellman shared secret or public key::

   long keyctl(KEYCTL_DH_COMPUTE, struct keyctl_dh_params *params,
               char *buffer, size_t buflen, struct keyctl_kdf_params *kdf);

The params struct contains serial numbers for three keys::

    - The prime, p, known to both parties
    - The local private key
    - The base integer, which is either a shared generator or the
      remote public key

The value computed is::

   result = base ^ private (mod prime)

If the base is the shared generator, the result is the local
public key.  If the base is the remote public key, the result is
the shared secret.

If the parameter kdf is NULL, the following applies:

    - The buffer length must be at least the length of the prime, or zero.

    - If the buffer length is nonzero, the length of the result is
      returned when it is successfully calculated and copied in to the
      buffer. When the buffer length is zero, the minimum required
      buffer length is returned.

The kdf parameter allows the caller to apply a key derivation function
(KDF) on the Diffie-Hellman computation where only the result
of the KDF is returned to the caller. The KDF is characterized with
struct keyctl_kdf_params as follows:

    - ``char *hashname`` specifies the NUL terminated string identifying
      the hash used from the kernel crypto API and applied for the KDF
      operation. The KDF implementation complies with SP800-56A as well
      as with SP800-108 (the counter KDF).

    - ``char *otherinfo`` specifies the OtherInfo data as documented in
      SP800-56A section 5.8.1.2. The length of the buffer is given with
      otherinfolen. The format of OtherInfo is defined by the caller.
      The otherinfo pointer may be NULL if no OtherInfo shall be used.

This function will return error EOPNOTSUPP if the key type is not
supported, error ENOKEY if the key could not be found, or error
EACCES if the key is not readable by the caller. In addition, the
function will return EMSGSIZE when the parameter kdf is non-NULL
and either the buffer length or the OtherInfo length exceeds the
allowed length.

”h]”(hÌ)”}”(hŒ6Compute a Diffie-Hellman shared secret or public key::”h]”hŒ5Compute a Diffie-Hellman shared secret or public key:”…””}”(hjÙ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MDhjÕ  ubjC	  )”}”(hŒˆlong keyctl(KEYCTL_DH_COMPUTE, struct keyctl_dh_params *params,
            char *buffer, size_t buflen, struct keyctl_kdf_params *kdf);”h]”hŒˆlong keyctl(KEYCTL_DH_COMPUTE, struct keyctl_dh_params *params,
            char *buffer, size_t buflen, struct keyctl_kdf_params *kdf);”…””}”hjç  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MFhjÕ  ubhÌ)”}”(hŒ:The params struct contains serial numbers for three keys::”h]”hŒ9The params struct contains serial numbers for three keys:”…””}”(hjõ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MIhjÕ  ubjC	  )”}”(hŒ- The prime, p, known to both parties
- The local private key
- The base integer, which is either a shared generator or the
  remote public key”h]”hŒ- The prime, p, known to both parties
- The local private key
- The base integer, which is either a shared generator or the
  remote public key”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MKhjÕ  ubhÌ)”}”(hŒThe value computed is::”h]”hŒThe value computed is:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MPhjÕ  ubjC	  )”}”(hŒ#result = base ^ private (mod prime)”h]”hŒ#result = base ^ private (mod prime)”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MRhjÕ  ubhÌ)”}”(hŒIf the base is the shared generator, the result is the local
public key.  If the base is the remote public key, the result is
the shared secret.”h]”hŒIf the base is the shared generator, the result is the local
public key.  If the base is the remote public key, the result is
the shared secret.”…””}”(hj-  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MThjÕ  ubhÌ)”}”(hŒ4If the parameter kdf is NULL, the following applies:”h]”hŒ4If the parameter kdf is NULL, the following applies:”…””}”(hj;  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MXhjÕ  ubhø)”}”(hX&  - The buffer length must be at least the length of the prime, or zero.

- If the buffer length is nonzero, the length of the result is
  returned when it is successfully calculated and copied in to the
  buffer. When the buffer length is zero, the minimum required
  buffer length is returned.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒEThe buffer length must be at least the length of the prime, or zero.
”h]”hÌ)”}”(hŒDThe buffer length must be at least the length of the prime, or zero.”h]”hŒDThe buffer length must be at least the length of the prime, or zero.”…””}”(hjT  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MZhjP  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjM  ubj*  )”}”(hŒÖIf the buffer length is nonzero, the length of the result is
returned when it is successfully calculated and copied in to the
buffer. When the buffer length is zero, the minimum required
buffer length is returned.
”h]”hÌ)”}”(hŒÕIf the buffer length is nonzero, the length of the result is
returned when it is successfully calculated and copied in to the
buffer. When the buffer length is zero, the minimum required
buffer length is returned.”h]”hŒÕIf the buffer length is nonzero, the length of the result is
returned when it is successfully calculated and copied in to the
buffer. When the buffer length is zero, the minimum required
buffer length is returned.”…””}”(hjl  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M\hjh  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjM  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j•  uh1j$  h³hÊh´MZhjI  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´MZhjÕ  ubhÌ)”}”(hŒíThe kdf parameter allows the caller to apply a key derivation function
(KDF) on the Diffie-Hellman computation where only the result
of the KDF is returned to the caller. The KDF is characterized with
struct keyctl_kdf_params as follows:”h]”hŒíThe kdf parameter allows the caller to apply a key derivation function
(KDF) on the Diffie-Hellman computation where only the result
of the KDF is returned to the caller. The KDF is characterized with
struct keyctl_kdf_params as follows:”…””}”(hjŒ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MahjÕ  ubhø)”}”(hX  - ``char *hashname`` specifies the NUL terminated string identifying
  the hash used from the kernel crypto API and applied for the KDF
  operation. The KDF implementation complies with SP800-56A as well
  as with SP800-108 (the counter KDF).

- ``char *otherinfo`` specifies the OtherInfo data as documented in
  SP800-56A section 5.8.1.2. The length of the buffer is given with
  otherinfolen. The format of OtherInfo is defined by the caller.
  The otherinfo pointer may be NULL if no OtherInfo shall be used.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒë``char *hashname`` specifies the NUL terminated string identifying
the hash used from the kernel crypto API and applied for the KDF
operation. The KDF implementation complies with SP800-56A as well
as with SP800-108 (the counter KDF).
”h]”hÌ)”}”(hŒê``char *hashname`` specifies the NUL terminated string identifying
the hash used from the kernel crypto API and applied for the KDF
operation. The KDF implementation complies with SP800-56A as well
as with SP800-108 (the counter KDF).”h]”(hŒliteral”“”)”}”(hŒ``char *hashname``”h]”hŒchar *hashname”…””}”(hj«  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj¥  ubhŒØ specifies the NUL terminated string identifying
the hash used from the kernel crypto API and applied for the KDF
operation. The KDF implementation complies with SP800-56A as well
as with SP800-108 (the counter KDF).”…””}”(hj¥  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mfhj¡  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjž  ubj*  )”}”(hX  ``char *otherinfo`` specifies the OtherInfo data as documented in
SP800-56A section 5.8.1.2. The length of the buffer is given with
otherinfolen. The format of OtherInfo is defined by the caller.
The otherinfo pointer may be NULL if no OtherInfo shall be used.
”h]”hÌ)”}”(hX  ``char *otherinfo`` specifies the OtherInfo data as documented in
SP800-56A section 5.8.1.2. The length of the buffer is given with
otherinfolen. The format of OtherInfo is defined by the caller.
The otherinfo pointer may be NULL if no OtherInfo shall be used.”h]”(jª  )”}”(hŒ``char *otherinfo``”h]”hŒchar *otherinfo”…””}”(hjÑ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjÍ  ubhŒñ specifies the OtherInfo data as documented in
SP800-56A section 5.8.1.2. The length of the buffer is given with
otherinfolen. The format of OtherInfo is defined by the caller.
The otherinfo pointer may be NULL if no OtherInfo shall be used.”…””}”(hjÍ  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MkhjÉ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjž  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j•  uh1j$  h³hÊh´Mfhjš  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´MfhjÕ  ubhÌ)”}”(hXU  This function will return error EOPNOTSUPP if the key type is not
supported, error ENOKEY if the key could not be found, or error
EACCES if the key is not readable by the caller. In addition, the
function will return EMSGSIZE when the parameter kdf is non-NULL
and either the buffer length or the OtherInfo length exceeds the
allowed length.”h]”hXU  This function will return error EOPNOTSUPP if the key type is not
supported, error ENOKEY if the key could not be found, or error
EACCES if the key is not readable by the caller. In addition, the
function will return EMSGSIZE when the parameter kdf is non-NULL
and either the buffer length or the OtherInfo length exceeds the
allowed length.”…””}”(hjû  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MphjÕ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX[  Restrict keyring linkage::

   long keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring,
               const char *type, const char *restriction);

An existing keyring can restrict linkage of additional keys by evaluating
the contents of the key according to a restriction scheme.

"keyring" is the key ID for an existing keyring to apply a restriction
to. It may be empty or may already have keys linked. Existing linked keys
will remain in the keyring even if the new restriction would reject them.

"type" is a registered key type.

"restriction" is a string describing how key linkage is to be restricted.
The format varies depending on the key type, and the string is passed to
the lookup_restriction() function for the requested type.  It may specify
a method and relevant data for the restriction such as signature
verification or constraints on key payload. If the requested key type is
later unregistered, no keys may be added to the keyring after the key type
is removed.

To apply a keyring restriction the process must have Set Attribute
permission and the keyring must not be previously restricted.

One application of restricted keyrings is to verify X.509 certificate
chains or individual certificate signatures using the asymmetric key type.
See Documentation/crypto/asymmetric-keys.rst for specific restrictions
applicable to the asymmetric key type.

”h]”(hÌ)”}”(hŒRestrict keyring linkage::”h]”hŒRestrict keyring linkage:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mxhj  ubjC	  )”}”(hŒrlong keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring,
            const char *type, const char *restriction);”h]”hŒrlong keyctl(KEYCTL_RESTRICT_KEYRING, key_serial_t keyring,
            const char *type, const char *restriction);”…””}”hj!  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mzhj  ubhÌ)”}”(hŒ„An existing keyring can restrict linkage of additional keys by evaluating
the contents of the key according to a restriction scheme.”h]”hŒ„An existing keyring can restrict linkage of additional keys by evaluating
the contents of the key according to a restriction scheme.”…””}”(hj/  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M}hj  ubhÌ)”}”(hŒÚ"keyring" is the key ID for an existing keyring to apply a restriction
to. It may be empty or may already have keys linked. Existing linked keys
will remain in the keyring even if the new restriction would reject them.”h]”hŒÞâ€œkeyringâ€ is the key ID for an existing keyring to apply a restriction
to. It may be empty or may already have keys linked. Existing linked keys
will remain in the keyring even if the new restriction would reject them.”…””}”(hj=  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M€hj  ubhÌ)”}”(hŒ "type" is a registered key type.”h]”hŒ$â€œtypeâ€ is a registered key type.”…””}”(hjK  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M„hj  ubhÌ)”}”(hX½  "restriction" is a string describing how key linkage is to be restricted.
The format varies depending on the key type, and the string is passed to
the lookup_restriction() function for the requested type.  It may specify
a method and relevant data for the restriction such as signature
verification or constraints on key payload. If the requested key type is
later unregistered, no keys may be added to the keyring after the key type
is removed.”h]”hXÁ  â€œrestrictionâ€ is a string describing how key linkage is to be restricted.
The format varies depending on the key type, and the string is passed to
the lookup_restriction() function for the requested type.  It may specify
a method and relevant data for the restriction such as signature
verification or constraints on key payload. If the requested key type is
later unregistered, no keys may be added to the keyring after the key type
is removed.”…””}”(hjY  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M†hj  ubhÌ)”}”(hŒ€To apply a keyring restriction the process must have Set Attribute
permission and the keyring must not be previously restricted.”h]”hŒ€To apply a keyring restriction the process must have Set Attribute
permission and the keyring must not be previously restricted.”…””}”(hjg  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MŽhj  ubhÌ)”}”(hŒþOne application of restricted keyrings is to verify X.509 certificate
chains or individual certificate signatures using the asymmetric key type.
See Documentation/crypto/asymmetric-keys.rst for specific restrictions
applicable to the asymmetric key type.”h]”hŒþOne application of restricted keyrings is to verify X.509 certificate
chains or individual certificate signatures using the asymmetric key type.
See Documentation/crypto/asymmetric-keys.rst for specific restrictions
applicable to the asymmetric key type.”…””}”(hju  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M‘hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX  Query an asymmetric key::

   long keyctl(KEYCTL_PKEY_QUERY,
               key_serial_t key_id, unsigned long reserved,
               const char *params,
               struct keyctl_pkey_query *info);

Get information about an asymmetric key.  Specific algorithms and
encodings may be queried by using the ``params`` argument.  This is a
string containing a space- or tab-separated string of key-value pairs.
Currently supported keys include ``enc`` and ``hash``.  The information
is returned in the keyctl_pkey_query struct::

   __u32   supported_ops;
   __u32   key_size;
   __u16   max_data_size;
   __u16   max_sig_size;
   __u16   max_enc_size;
   __u16   max_dec_size;
   __u32   __spare[10];

``supported_ops`` contains a bit mask of flags indicating which ops are
supported.  This is constructed from a bitwise-OR of::

   KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}

``key_size`` indicated the size of the key in bits.

``max_*_size`` indicate the maximum sizes in bytes of a blob of data to be
signed, a signature blob, a blob to be encrypted and a blob to be
decrypted.

``__spare[]`` must be set to 0.  This is intended for future use to hand
over one or more passphrases needed unlock a key.

If successful, 0 is returned.  If the key is not an asymmetric key,
EOPNOTSUPP is returned.

”h]”(hÌ)”}”(hŒQuery an asymmetric key::”h]”hŒQuery an asymmetric key:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M—hj‰  ubjC	  )”}”(hŒ¤long keyctl(KEYCTL_PKEY_QUERY,
            key_serial_t key_id, unsigned long reserved,
            const char *params,
            struct keyctl_pkey_query *info);”h]”hŒ¤long keyctl(KEYCTL_PKEY_QUERY,
            key_serial_t key_id, unsigned long reserved,
            const char *params,
            struct keyctl_pkey_query *info);”…””}”hj›  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M™hj‰  ubhÌ)”}”(hXD  Get information about an asymmetric key.  Specific algorithms and
encodings may be queried by using the ``params`` argument.  This is a
string containing a space- or tab-separated string of key-value pairs.
Currently supported keys include ``enc`` and ``hash``.  The information
is returned in the keyctl_pkey_query struct::”h]”(hŒhGet information about an asymmetric key.  Specific algorithms and
encodings may be queried by using the ”…””}”(hj©  h²hh³Nh´Nubjª  )”}”(hŒ
``params``”h]”hŒparams”…””}”(hj±  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj©  ubhŒ~ argument.  This is a
string containing a space- or tab-separated string of key-value pairs.
Currently supported keys include ”…””}”(hj©  h²hh³Nh´Nubjª  )”}”(hŒ``enc``”h]”hŒenc”…””}”(hjÃ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj©  ubhŒ and ”…””}”(hj©  h²hh³Nh´Nubjª  )”}”(hŒ``hash``”h]”hŒhash”…””}”(hjÕ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj©  ubhŒ?.  The information
is returned in the keyctl_pkey_query struct:”…””}”(hj©  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mžhj‰  ubjC	  )”}”(hŒ–__u32   supported_ops;
__u32   key_size;
__u16   max_data_size;
__u16   max_sig_size;
__u16   max_enc_size;
__u16   max_dec_size;
__u32   __spare[10];”h]”hŒ–__u32   supported_ops;
__u32   key_size;
__u16   max_data_size;
__u16   max_sig_size;
__u16   max_enc_size;
__u16   max_dec_size;
__u32   __spare[10];”…””}”hjí  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M¤hj‰  ubhÌ)”}”(hŒ~``supported_ops`` contains a bit mask of flags indicating which ops are
supported.  This is constructed from a bitwise-OR of::”h]”(jª  )”}”(hŒ``supported_ops``”h]”hŒsupported_ops”…””}”(hjÿ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjû  ubhŒl contains a bit mask of flags indicating which ops are
supported.  This is constructed from a bitwise-OR of:”…””}”(hjû  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¬hj‰  ubjC	  )”}”(hŒ-KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}”h]”hŒ-KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M¯hj‰  ubhÌ)”}”(hŒ3``key_size`` indicated the size of the key in bits.”h]”(jª  )”}”(hŒ``key_size``”h]”hŒkey_size”…””}”(hj)  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj%  ubhŒ' indicated the size of the key in bits.”…””}”(hj%  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M±hj‰  ubhÌ)”}”(hŒ—``max_*_size`` indicate the maximum sizes in bytes of a blob of data to be
signed, a signature blob, a blob to be encrypted and a blob to be
decrypted.”h]”(jª  )”}”(hŒ``max_*_size``”h]”hŒ
max_*_size”…””}”(hjE  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjA  ubhŒ‰ indicate the maximum sizes in bytes of a blob of data to be
signed, a signature blob, a blob to be encrypted and a blob to be
decrypted.”…””}”(hjA  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M³hj‰  ubhÌ)”}”(hŒz``__spare[]`` must be set to 0.  This is intended for future use to hand
over one or more passphrases needed unlock a key.”h]”(jª  )”}”(hŒ``__spare[]``”h]”hŒ	__spare[]”…””}”(hja  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj]  ubhŒm must be set to 0.  This is intended for future use to hand
over one or more passphrases needed unlock a key.”…””}”(hj]  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M·hj‰  ubhÌ)”}”(hŒ[If successful, 0 is returned.  If the key is not an asymmetric key,
EOPNOTSUPP is returned.”h]”hŒ[If successful, 0 is returned.  If the key is not an asymmetric key,
EOPNOTSUPP is returned.”…””}”(hjy  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mºhj‰  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hX›  Encrypt, decrypt, sign or verify a blob using an asymmetric key::

   long keyctl(KEYCTL_PKEY_ENCRYPT,
               const struct keyctl_pkey_params *params,
               const char *info,
               const void *in,
               void *out);

   long keyctl(KEYCTL_PKEY_DECRYPT,
               const struct keyctl_pkey_params *params,
               const char *info,
               const void *in,
               void *out);

   long keyctl(KEYCTL_PKEY_SIGN,
               const struct keyctl_pkey_params *params,
               const char *info,
               const void *in,
               void *out);

   long keyctl(KEYCTL_PKEY_VERIFY,
               const struct keyctl_pkey_params *params,
               const char *info,
               const void *in,
               const void *in2);

Use an asymmetric key to perform a public-key cryptographic operation a
blob of data.  For encryption and verification, the asymmetric key may
only need the public parts to be available, but for decryption and signing
the private parts are required also.

The parameter block pointed to by params contains a number of integer
values::

   __s32           key_id;
   __u32           in_len;
   __u32           out_len;
   __u32           in2_len;

``key_id`` is the ID of the asymmetric key to be used.  ``in_len`` and
``in2_len`` indicate the amount of data in the in and in2 buffers and
``out_len`` indicates the size of the out buffer as appropriate for the
above operations.

For a given operation, the in and out buffers are used as follows::

   Operation ID            in,in_len       out,out_len     in2,in2_len
   ======================= =============== =============== ===============
   KEYCTL_PKEY_ENCRYPT     Raw data        Encrypted data  -
   KEYCTL_PKEY_DECRYPT     Encrypted data  Raw data        -
   KEYCTL_PKEY_SIGN        Raw data        Signature       -
   KEYCTL_PKEY_VERIFY      Raw data        -               Signature

``info`` is a string of key=value pairs that supply supplementary
information.  These include:

   ``enc=<encoding>`` The encoding of the encrypted/signature blob.  This
                   can be "pkcs1" for RSASSA-PKCS1-v1.5 or
                   RSAES-PKCS1-v1.5; "pss" for "RSASSA-PSS"; "oaep" for
                   "RSAES-OAEP".  If omitted or is "raw", the raw output
                   of the encryption function is specified.

   ``hash=<algo>`` If the data buffer contains the output of a hash
                   function and the encoding includes some indication of
                   which hash function was used, the hash function can be
                   specified with this, eg. "hash=sha256".

The ``__spare[]`` space in the parameter block must be set to 0.  This is
intended, amongst other things, to allow the passing of passphrases
required to unlock a key.

If successful, encrypt, decrypt and sign all return the amount of data
written into the output buffer.  Verification returns 0 on success.

”h]”(hÌ)”}”(hŒAEncrypt, decrypt, sign or verify a blob using an asymmetric key::”h]”hŒ@Encrypt, decrypt, sign or verify a blob using an asymmetric key:”…””}”(hj‘  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¾hj  ubjC	  )”}”(hX¤  long keyctl(KEYCTL_PKEY_ENCRYPT,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            void *out);

long keyctl(KEYCTL_PKEY_DECRYPT,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            void *out);

long keyctl(KEYCTL_PKEY_SIGN,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            void *out);

long keyctl(KEYCTL_PKEY_VERIFY,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            const void *in2);”h]”hX¤  long keyctl(KEYCTL_PKEY_ENCRYPT,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            void *out);

long keyctl(KEYCTL_PKEY_DECRYPT,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            void *out);

long keyctl(KEYCTL_PKEY_SIGN,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            void *out);

long keyctl(KEYCTL_PKEY_VERIFY,
            const struct keyctl_pkey_params *params,
            const char *info,
            const void *in,
            const void *in2);”…””}”hjŸ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MÀhj  ubhÌ)”}”(hŒþUse an asymmetric key to perform a public-key cryptographic operation a
blob of data.  For encryption and verification, the asymmetric key may
only need the public parts to be available, but for decryption and signing
the private parts are required also.”h]”hŒþUse an asymmetric key to perform a public-key cryptographic operation a
blob of data.  For encryption and verification, the asymmetric key may
only need the public parts to be available, but for decryption and signing
the private parts are required also.”…””}”(hj­  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MØhj  ubhÌ)”}”(hŒNThe parameter block pointed to by params contains a number of integer
values::”h]”hŒMThe parameter block pointed to by params contains a number of integer
values:”…””}”(hj»  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÝhj  ubjC	  )”}”(hŒa__s32           key_id;
__u32           in_len;
__u32           out_len;
__u32           in2_len;”h]”hŒa__s32           key_id;
__u32           in_len;
__u32           out_len;
__u32           in2_len;”…””}”hjÉ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Màhj  ubhÌ)”}”(hŒæ``key_id`` is the ID of the asymmetric key to be used.  ``in_len`` and
``in2_len`` indicate the amount of data in the in and in2 buffers and
``out_len`` indicates the size of the out buffer as appropriate for the
above operations.”h]”(jª  )”}”(hŒ
``key_id``”h]”hŒkey_id”…””}”(hjÛ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj×  ubhŒ. is the ID of the asymmetric key to be used.  ”…””}”(hj×  h²hh³Nh´Nubjª  )”}”(hŒ
``in_len``”h]”hŒin_len”…””}”(hjí  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj×  ubhŒ and
”…””}”(hj×  h²hh³Nh´Nubjª  )”}”(hŒ``in2_len``”h]”hŒin2_len”…””}”(hjÿ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj×  ubhŒ; indicate the amount of data in the in and in2 buffers and
”…””}”(hj×  h²hh³Nh´Nubjª  )”}”(hŒ``out_len``”h]”hŒout_len”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj×  ubhŒN indicates the size of the out buffer as appropriate for the
above operations.”…””}”(hj×  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Måhj  ubhÌ)”}”(hŒCFor a given operation, the in and out buffers are used as follows::”h]”hŒBFor a given operation, the in and out buffers are used as follows:”…””}”(hj)  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mêhj  ubjC	  )”}”(hX{  Operation ID            in,in_len       out,out_len     in2,in2_len
======================= =============== =============== ===============
KEYCTL_PKEY_ENCRYPT     Raw data        Encrypted data  -
KEYCTL_PKEY_DECRYPT     Encrypted data  Raw data        -
KEYCTL_PKEY_SIGN        Raw data        Signature       -
KEYCTL_PKEY_VERIFY      Raw data        -               Signature”h]”hX{  Operation ID            in,in_len       out,out_len     in2,in2_len
======================= =============== =============== ===============
KEYCTL_PKEY_ENCRYPT     Raw data        Encrypted data  -
KEYCTL_PKEY_DECRYPT     Encrypted data  Raw data        -
KEYCTL_PKEY_SIGN        Raw data        Signature       -
KEYCTL_PKEY_VERIFY      Raw data        -               Signature”…””}”hj7  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mìhj  ubhÌ)”}”(hŒ^``info`` is a string of key=value pairs that supply supplementary
information.  These include:”h]”(jª  )”}”(hŒ``info``”h]”hŒinfo”…””}”(hjI  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjE  ubhŒV is a string of key=value pairs that supply supplementary
information.  These include:”…””}”(hjE  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Móhj  ubhø)”}”(hXJ  ``enc=<encoding>`` The encoding of the encrypted/signature blob.  This
                can be "pkcs1" for RSASSA-PKCS1-v1.5 or
                RSAES-PKCS1-v1.5; "pss" for "RSASSA-PSS"; "oaep" for
                "RSAES-OAEP".  If omitted or is "raw", the raw output
                of the encryption function is specified.

``hash=<algo>`` If the data buffer contains the output of a hash
                function and the encoding includes some indication of
                which hash function was used, the hash function can be
                specified with this, eg. "hash=sha256".
”h]”hŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hX  ``enc=<encoding>`` The encoding of the encrypted/signature blob.  This
can be "pkcs1" for RSASSA-PKCS1-v1.5 or
RSAES-PKCS1-v1.5; "pss" for "RSASSA-PSS"; "oaep" for
"RSAES-OAEP".  If omitted or is "raw", the raw output
of the encryption function is specified.
”h]”(hŒterm”“”)”}”(hŒF``enc=<encoding>`` The encoding of the encrypted/signature blob.  This”h]”(jª  )”}”(hŒ``enc=<encoding>``”h]”hŒenc=<encoding>”…””}”(hjv  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjr  ubhŒ4 The encoding of the encrypted/signature blob.  This”…””}”(hjr  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1jp  h³hÊh´Múhjl  ubhŒ
definition”“”)”}”(hhh]”hÌ)”}”(hŒ»can be "pkcs1" for RSASSA-PKCS1-v1.5 or
RSAES-PKCS1-v1.5; "pss" for "RSASSA-PSS"; "oaep" for
"RSAES-OAEP".  If omitted or is "raw", the raw output
of the encryption function is specified.”h]”hŒÓcan be â€œpkcs1â€ for RSASSA-PKCS1-v1.5 or
RSAES-PKCS1-v1.5; â€œpssâ€ for â€œRSASSA-PSSâ€; â€œoaepâ€ for
â€œRSAES-OAEPâ€.  If omitted or is â€œrawâ€, the raw output
of the encryption function is specified.”…””}”(hj“  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M÷hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jŽ  hjl  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jj  h³hÊh´Múhjg  ubjk  )”}”(hŒÖ``hash=<algo>`` If the data buffer contains the output of a hash
function and the encoding includes some indication of
which hash function was used, the hash function can be
specified with this, eg. "hash=sha256".
”h]”(jq  )”}”(hŒ@``hash=<algo>`` If the data buffer contains the output of a hash”h]”(jª  )”}”(hŒ``hash=<algo>``”h]”hŒhash=<algo>”…””}”(hjµ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj±  ubhŒ1 If the data buffer contains the output of a hash”…””}”(hj±  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1jp  h³hÊh´Mÿhj­  ubj  )”}”(hhh]”hÌ)”}”(hŒ”function and the encoding includes some indication of
which hash function was used, the hash function can be
specified with this, eg. "hash=sha256".”h]”hŒ˜function and the encoding includes some indication of
which hash function was used, the hash function can be
specified with this, eg. â€œhash=sha256â€.”…””}”(hjÐ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MýhjÍ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jŽ  hj­  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jj  h³hÊh´Mÿhjg  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1je  hja  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Möhj  ubhÌ)”}”(hŒ§The ``__spare[]`` space in the parameter block must be set to 0.  This is
intended, amongst other things, to allow the passing of passphrases
required to unlock a key.”•Ý7     h]”(hŒThe ”…””}”(hjö  h²hh³Nh´Nubjª  )”}”(hŒ``__spare[]``”h]”hŒ	__spare[]”…””}”(hjþ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjö  ubhŒ– space in the parameter block must be set to 0.  This is
intended, amongst other things, to allow the passing of passphrases
required to unlock a key.”…””}”(hjö  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj  ubhÌ)”}”(hŒŠIf successful, encrypt, decrypt and sign all return the amount of data
written into the output buffer.  Verification returns 0 on success.”h]”hŒŠIf successful, encrypt, decrypt and sign all return the amount of data
written into the output buffer.  Verification returns 0 on success.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubj*  )”}”(hXÑ  Watch a key or keyring for changes::

   long keyctl(KEYCTL_WATCH_KEY, key_serial_t key, int queue_fd,
               const struct watch_notification_filter *filter);

This will set or remove a watch for changes on the specified key or
keyring.

"key" is the ID of the key to be watched.

"queue_fd" is a file descriptor referring to an open pipe which
manages the buffer into which notifications will be delivered.

"filter" is either NULL to remove a watch or a filter specification to
indicate what events are required from the key.

See Documentation/core-api/watch_queue.rst for more information.

Note that only one watch may be emplaced for any particular { key,
queue_fd } combination.

Notification records look like::

   struct key_notification {
           struct watch_notification watch;
           __u32   key_id;
           __u32   aux;
   };

In this, watch::type will be "WATCH_TYPE_KEY_NOTIFY" and subtype will be
one of::

   NOTIFY_KEY_INSTANTIATED
   NOTIFY_KEY_UPDATED
   NOTIFY_KEY_LINKED
   NOTIFY_KEY_UNLINKED
   NOTIFY_KEY_CLEARED
   NOTIFY_KEY_REVOKED
   NOTIFY_KEY_INVALIDATED
   NOTIFY_KEY_SETATTR

Where these indicate a key being instantiated/rejected, updated, a link
being made in a keyring, a link being removed from a keyring, a keyring
being cleared, a key being revoked, a key being invalidated or a key
having one of its attributes changed (user, group, perm, timeout,
restriction).

If a watched key is deleted, a basic watch_notification will be issued
with "type" set to WATCH_TYPE_META and "subtype" set to
watch_meta_removal_notification.  The watchpoint ID will be set in the
"info" field.

This needs to be configured by enabling:

   "Provide key/keyring change notifications" (KEY_NOTIFICATIONS)

”h]”(hÌ)”}”(hŒ$Watch a key or keyring for changes::”h]”hŒ#Watch a key or keyring for changes:”…””}”(hj.  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M	hj*  ubjC	  )”}”(hŒzlong keyctl(KEYCTL_WATCH_KEY, key_serial_t key, int queue_fd,
            const struct watch_notification_filter *filter);”h]”hŒzlong keyctl(KEYCTL_WATCH_KEY, key_serial_t key, int queue_fd,
            const struct watch_notification_filter *filter);”…””}”hj<  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhj*  ubhÌ)”}”(hŒLThis will set or remove a watch for changes on the specified key or
keyring.”h]”hŒLThis will set or remove a watch for changes on the specified key or
keyring.”…””}”(hjJ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubhÌ)”}”(hŒ)"key" is the ID of the key to be watched.”h]”hŒ-â€œkeyâ€ is the ID of the key to be watched.”…””}”(hjX  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubhÌ)”}”(hŒ~"queue_fd" is a file descriptor referring to an open pipe which
manages the buffer into which notifications will be delivered.”h]”hŒ‚â€œqueue_fdâ€ is a file descriptor referring to an open pipe which
manages the buffer into which notifications will be delivered.”…””}”(hjf  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubhÌ)”}”(hŒv"filter" is either NULL to remove a watch or a filter specification to
indicate what events are required from the key.”h]”hŒzâ€œfilterâ€ is either NULL to remove a watch or a filter specification to
indicate what events are required from the key.”…””}”(hjt  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubhÌ)”}”(hŒ@See Documentation/core-api/watch_queue.rst for more information.”h]”hŒ@See Documentation/core-api/watch_queue.rst for more information.”…””}”(hj‚  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubhÌ)”}”(hŒZNote that only one watch may be emplaced for any particular { key,
queue_fd } combination.”h]”hŒZNote that only one watch may be emplaced for any particular { key,
queue_fd } combination.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubhÌ)”}”(hŒ Notification records look like::”h]”hŒNotification records look like:”…””}”(hjž  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj*  ubjC	  )”}”(hŒrstruct key_notification {
        struct watch_notification watch;
        __u32   key_id;
        __u32   aux;
};”h]”hŒrstruct key_notification {
        struct watch_notification watch;
        __u32   key_id;
        __u32   aux;
};”…””}”hj¬  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M hj*  ubhÌ)”}”(hŒQIn this, watch::type will be "WATCH_TYPE_KEY_NOTIFY" and subtype will be
one of::”h]”hŒTIn this, watch::type will be â€œWATCH_TYPE_KEY_NOTIFYâ€ and subtype will be
one of:”…””}”(hjº  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M&hj*  ubjC	  )”}”(hŒ NOTIFY_KEY_INSTANTIATED
NOTIFY_KEY_UPDATED
NOTIFY_KEY_LINKED
NOTIFY_KEY_UNLINKED
NOTIFY_KEY_CLEARED
NOTIFY_KEY_REVOKED
NOTIFY_KEY_INVALIDATED
NOTIFY_KEY_SETATTR”h]”hŒ NOTIFY_KEY_INSTANTIATED
NOTIFY_KEY_UPDATED
NOTIFY_KEY_LINKED
NOTIFY_KEY_UNLINKED
NOTIFY_KEY_CLEARED
NOTIFY_KEY_REVOKED
NOTIFY_KEY_INVALIDATED
NOTIFY_KEY_SETATTR”…””}”hjÈ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M)hj*  ubhÌ)”}”(hX$  Where these indicate a key being instantiated/rejected, updated, a link
being made in a keyring, a link being removed from a keyring, a keyring
being cleared, a key being revoked, a key being invalidated or a key
having one of its attributes changed (user, group, perm, timeout,
restriction).”h]”hX$  Where these indicate a key being instantiated/rejected, updated, a link
being made in a keyring, a link being removed from a keyring, a keyring
being cleared, a key being revoked, a key being invalidated or a key
having one of its attributes changed (user, group, perm, timeout,
restriction).”…””}”(hjÖ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M2hj*  ubhÌ)”}”(hŒÓIf a watched key is deleted, a basic watch_notification will be issued
with "type" set to WATCH_TYPE_META and "subtype" set to
watch_meta_removal_notification.  The watchpoint ID will be set in the
"info" field.”h]”hŒßIf a watched key is deleted, a basic watch_notification will be issued
with â€œtypeâ€ set to WATCH_TYPE_META and â€œsubtypeâ€ set to
watch_meta_removal_notification.  The watchpoint ID will be set in the
â€œinfoâ€ field.”…””}”(hjä  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M8hj*  ubhÌ)”}”(hŒ(This needs to be configured by enabling:”h]”hŒ(This needs to be configured by enabling:”…””}”(hjò  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M=hj*  ubhø)”}”(hŒ@"Provide key/keyring change notifications" (KEY_NOTIFICATIONS)

”h]”hÌ)”}”(hŒ>"Provide key/keyring change notifications" (KEY_NOTIFICATIONS)”h]”hŒBâ€œProvide key/keyring change notificationsâ€ (KEY_NOTIFICATIONS)”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M?hj   ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M?hj*  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¶  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´M½hj²  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M½hjT
  h²hubeh}”(h]”jì  ah ]”h"]”Œuserspace system call interface”ah$]”h&]”uh1hµhh·h²hh³hÊh´Mbubh¶)”}”(hhh]”(h»)”}”(hŒKernel Services”h]”hŒKernel Services”…””}”(hj4  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  j  uh1hºhj1  h²hh³hÊh´MCubhÌ)”}”(hŒ‚The kernel services for key management are fairly simple to deal with. They can
be broken down into two areas: keys and key types.”h]”hŒ‚The kernel services for key management are fairly simple to deal with. They can
be broken down into two areas: keys and key types.”…””}”(hjB  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MEhj1  h²hubhÌ)”}”(hXÖ  Dealing with keys is fairly straightforward. Firstly, the kernel service
registers its type, then it searches for a key of that type. It should retain
the key as long as it has need of it, and then it should release it. For a
filesystem or device file, a search would probably be performed during the open
call, and the key released upon close. How to deal with conflicting keys due to
two different users opening the same file is left to the filesystem author to
solve.”h]”hXÖ  Dealing with keys is fairly straightforward. Firstly, the kernel service
registers its type, then it searches for a key of that type. It should retain
the key as long as it has need of it, and then it should release it. For a
filesystem or device file, a search would probably be performed during the open
call, and the key released upon close. How to deal with conflicting keys due to
two different users opening the same file is left to the filesystem author to
solve.”…””}”(hjP  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MHhj1  h²hubhÌ)”}”(hŒCTo access the key manager, the following header must be #included::”h]”hŒBTo access the key manager, the following header must be #included:”…””}”(hj^  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MPhj1  h²hubjC	  )”}”(hŒ<linux/key.h>”h]”hŒ<linux/key.h>”…””}”hjl  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MRhj1  h²hubhÌ)”}”(hŒ Specific key types should have a header file under include/keys/ that should be
used to access that type.  For keys of type "user", for example, that would be::”h]”hŒ£Specific key types should have a header file under include/keys/ that should be
used to access that type.  For keys of type â€œuserâ€, for example, that would be:”…””}”(hjz  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MThj1  h²hubjC	  )”}”(hŒ<keys/user-type.h>”h]”hŒ<keys/user-type.h>”…””}”hjˆ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MWhj1  h²hubhÌ)”}”(hŒTNote that there are two different types of pointers to keys that may be
encountered:”h]”hŒTNote that there are two different types of pointers to keys that may be
encountered:”…””}”(hj–  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MYhj1  h²hubhø)”}”(hX[  *  struct key *

   This simply points to the key structure itself. Key structures will be at
   least four-byte aligned.

*  key_ref_t

   This is equivalent to a ``struct key *``, but the least significant bit is set
   if the caller "possesses" the key. By "possession" it is meant that the
   calling processes has a searchable link to the key from one of its
   keyrings. There are three functions for dealing with these::

      key_ref_t make_key_ref(const struct key *key, bool possession);

      struct key *key_ref_to_ptr(const key_ref_t key_ref);

      bool is_key_possessed(const key_ref_t key_ref);

   The first function constructs a key reference from a key pointer and
   possession information (which must be true or false).

   The second function retrieves the key pointer from a reference and the
   third retrieves the possession flag.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒqstruct key *

This simply points to the key structure itself. Key structures will be at
least four-byte aligned.
”h]”(hÌ)”}”(hŒstruct key *”h]”hŒstruct key *”…””}”(hj¯  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M\hj«  ubhÌ)”}”(hŒbThis simply points to the key structure itself. Key structures will be at
least four-byte aligned.”h]”hŒbThis simply points to the key structure itself. Key structures will be at
least four-byte aligned.”…””}”(hj½  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M^hj«  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¨  ubj*  )”}”(hX¼  key_ref_t

This is equivalent to a ``struct key *``, but the least significant bit is set
if the caller "possesses" the key. By "possession" it is meant that the
calling processes has a searchable link to the key from one of its
keyrings. There are three functions for dealing with these::

   key_ref_t make_key_ref(const struct key *key, bool possession);

   struct key *key_ref_to_ptr(const key_ref_t key_ref);

   bool is_key_possessed(const key_ref_t key_ref);

The first function constructs a key reference from a key pointer and
possession information (which must be true or false).

The second function retrieves the key pointer from a reference and the
third retrieves the possession flag.
”h]”(hÌ)”}”(hŒ	key_ref_t”h]”hŒ	key_ref_t”…””}”(hjÕ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MahjÑ  ubhÌ)”}”(hX  This is equivalent to a ``struct key *``, but the least significant bit is set
if the caller "possesses" the key. By "possession" it is meant that the
calling processes has a searchable link to the key from one of its
keyrings. There are three functions for dealing with these::”h]”(hŒThis is equivalent to a ”…””}”(hjã  h²hh³Nh´Nubjª  )”}”(hŒ``struct key *``”h]”hŒstruct key *”…””}”(hjë  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjã  ubhŒõ, but the least significant bit is set
if the caller â€œpossessesâ€ the key. By â€œpossessionâ€ it is meant that the
calling processes has a searchable link to the key from one of its
keyrings. There are three functions for dealing with these:”…””}”(hjã  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MchjÑ  ubjC	  )”}”(hŒ¦key_ref_t make_key_ref(const struct key *key, bool possession);

struct key *key_ref_to_ptr(const key_ref_t key_ref);

bool is_key_possessed(const key_ref_t key_ref);”h]”hŒ¦key_ref_t make_key_ref(const struct key *key, bool possession);

struct key *key_ref_to_ptr(const key_ref_t key_ref);

bool is_key_possessed(const key_ref_t key_ref);”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MhhjÑ  ubhÌ)”}”(hŒzThe first function constructs a key reference from a key pointer and
possession information (which must be true or false).”h]”hŒzThe first function constructs a key reference from a key pointer and
possession information (which must be true or false).”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MnhjÑ  ubhÌ)”}”(hŒkThe second function retrieves the key pointer from a reference and the
third retrieves the possession flag.”h]”hŒkThe second function retrieves the key pointer from a reference and the
third retrieves the possession flag.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MqhjÑ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj¨  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´M\hj¤  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M\hj1  h²hubhÌ)”}”(hŒ¿When accessing a key's payload contents, certain precautions must be taken to
prevent access vs modification races. See the section "Notes on accessing
payload contents" for more information.”h]”hŒÅWhen accessing a keyâ€™s payload contents, certain precautions must be taken to
prevent access vs modification races. See the section â€œNotes on accessing
payload contentsâ€ for more information.”…””}”(hj?  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mthj1  h²hubhø)”}”(hXU  *  To search for a key, call::

       struct key *request_key(const struct key_type *type,
                               const char *description,
                               const char *callout_info);

   This is used to request a key or keyring with a description that matches
   the description specified according to the key type's match_preparse()
   method. This permits approximate matching to occur. If callout_string is
   not NULL, then /sbin/request-key will be invoked in an attempt to obtain
   the key from userspace. In that case, callout_string will be passed as an
   argument to the program.

   Should the function fail error ENOKEY, EKEYEXPIRED or EKEYREVOKED will be
   returned.

   If successful, the key will have been attached to the default keyring for
   implicitly obtained request-key keys, as set by KEYCTL_SET_REQKEY_KEYRING.

   See also Documentation/security/keys/request-key.rst.


*  To search for a key in a specific domain, call::

       struct key *request_key_tag(const struct key_type *type,
                                   const char *description,
                                   struct key_tag *domain_tag,
                                   const char *callout_info);

   This is identical to request_key(), except that a domain tag may be
   specifies that causes search algorithm to only match keys matching that
   tag.  The domain_tag may be NULL, specifying a global domain that is
   separate from any nominated domain.


*  To search for a key, passing auxiliary data to the upcaller, call::

       struct key *request_key_with_auxdata(const struct key_type *type,
                                            const char *description,
                                            struct key_tag *domain_tag,
                                            const void *callout_info,
                                            size_t callout_len,
                                            void *aux);

   This is identical to request_key_tag(), except that the auxiliary data is
   passed to the key_type->request_key() op if it exists, and the
   callout_info is a blob of length callout_len, if given (the length may be
   0).


*  To search for a key under RCU conditions, call::

       struct key *request_key_rcu(const struct key_type *type,
                                   const char *description,
                                   struct key_tag *domain_tag);

   which is similar to request_key_tag() except that it does not check for
   keys that are under construction and it will not call out to userspace to
   construct a key if it can't find a match.


*  When it is no longer required, the key should be released using::

       void key_put(struct key *key);

   Or::

       void key_ref_put(key_ref_t key_ref);

   These can be called from interrupt context. If CONFIG_KEYS is not set then
   the argument will not be parsed.


*  Extra references can be made to a key by calling one of the following
   functions::

       struct key *__key_get(struct key *key);
       struct key *key_get(struct key *key);

   Keys so references will need to be disposed of by calling key_put() when
   they've been finished with.  The key pointer passed in will be returned.

   In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set
   then the key will not be dereferenced and no increment will take place.


*  A key's serial number can be obtained by calling::

       key_serial_t key_serial(struct key *key);

   If key is NULL or if CONFIG_KEYS is not set then 0 will be returned (in the
   latter case without parsing the argument).


*  If a keyring was found in the search, this can be further searched by::

       key_ref_t keyring_search(key_ref_t keyring_ref,
                                const struct key_type *type,
                                const char *description,
                                bool recurse)

   This searches the specified keyring only (recurse == false) or keyring tree
   (recurse == true) specified for a matching key. Error ENOKEY is returned
   upon failure (use IS_ERR/PTR_ERR to determine). If successful, the returned
   key will need to be released.

   The possession attribute from the keyring reference is used to control
   access through the permissions mask and is propagated to the returned key
   reference pointer if successful.


*  A keyring can be created by::

       struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
                                 const struct cred *cred,
                                 key_perm_t perm,
                                 struct key_restriction *restrict_link,
                                 unsigned long flags,
                                 struct key *dest);

   This creates a keyring with the given attributes and returns it.  If dest
   is not NULL, the new keyring will be linked into the keyring to which it
   points.  No permission checks are made upon the destination keyring.

   Error EDQUOT can be returned if the keyring would overload the quota (pass
   KEY_ALLOC_NOT_IN_QUOTA in flags if the keyring shouldn't be accounted
   towards the user's quota).  Error ENOMEM can also be returned.

   If restrict_link is not NULL, it should point to a structure that contains
   the function that will be called each time an attempt is made to link a
   key into the new keyring.  The structure may also contain a key pointer
   and an associated key type.  The function is called to check whether a key
   may be added into the keyring or not.  The key type is used by the garbage
   collector to clean up function or data pointers in this structure if the
   given key type is unregistered.  Callers of key_create_or_update() within
   the kernel can pass KEY_ALLOC_BYPASS_RESTRICTION to suppress the check.
   An example of using this is to manage rings of cryptographic keys that are
   set up when the kernel boots where userspace is also permitted to add keys
   - provided they can be verified by a key the kernel already has.

   When called, the restriction function will be passed the keyring being
   added to, the key type, the payload of the key being added, and data to be
   used in the restriction check.  Note that when a new key is being created,
   this is called between payload preparsing and actual key creation.  The
   function should return 0 to allow the link or an error to reject it.

   A convenience function, restrict_link_reject, exists to always return
   -EPERM to in this case.


*  To check the validity of a key, this function can be called::

       int validate_key(struct key *key);

   This checks that the key in question hasn't expired or and hasn't been
   revoked. Should the key be invalid, error EKEYEXPIRED or EKEYREVOKED will
   be returned. If the key is NULL or if CONFIG_KEYS is not set then 0 will be
   returned (in the latter case without parsing the argument).


*  To register a key type, the following function should be called::

       int register_key_type(struct key_type *type);

   This will return error EEXIST if a type of the same name is already
   present.


*  To unregister a key type, call::

       void unregister_key_type(struct key_type *type);

”h]”j%  )”}”(hhh]”(j*  )”}”(hXk  To search for a key, call::

    struct key *request_key(const struct key_type *type,
                            const char *description,
                            const char *callout_info);

This is used to request a key or keyring with a description that matches
the description specified according to the key type's match_preparse()
method. This permits approximate matching to occur. If callout_string is
not NULL, then /sbin/request-key will be invoked in an attempt to obtain
the key from userspace. In that case, callout_string will be passed as an
argument to the program.

Should the function fail error ENOKEY, EKEYEXPIRED or EKEYREVOKED will be
returned.

If successful, the key will have been attached to the default keyring for
implicitly obtained request-key keys, as set by KEYCTL_SET_REQKEY_KEYRING.

See also Documentation/security/keys/request-key.rst.

”h]”(hÌ)”}”(hŒTo search for a key, call::”h]”hŒTo search for a key, call:”…””}”(hjX  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MxhjT  ubjC	  )”}”(hŒ˜struct key *request_key(const struct key_type *type,
                        const char *description,
                        const char *callout_info);”h]”hŒ˜struct key *request_key(const struct key_type *type,
                        const char *description,
                        const char *callout_info);”…””}”hjf  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MzhjT  ubhÌ)”}”(hX„  This is used to request a key or keyring with a description that matches
the description specified according to the key type's match_preparse()
method. This permits approximate matching to occur. If callout_string is
not NULL, then /sbin/request-key will be invoked in an attempt to obtain
the key from userspace. In that case, callout_string will be passed as an
argument to the program.”h]”hX†  This is used to request a key or keyring with a description that matches
the description specified according to the key typeâ€™s match_preparse()
method. This permits approximate matching to occur. If callout_string is
not NULL, then /sbin/request-key will be invoked in an attempt to obtain
the key from userspace. In that case, callout_string will be passed as an
argument to the program.”…””}”(hjt  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M~hjT  ubhÌ)”}”(hŒSShould the function fail error ENOKEY, EKEYEXPIRED or EKEYREVOKED will be
returned.”h]”hŒSShould the function fail error ENOKEY, EKEYEXPIRED or EKEYREVOKED will be
returned.”…””}”(hj‚  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M…hjT  ubhÌ)”}”(hŒ”If successful, the key will have been attached to the default keyring for
implicitly obtained request-key keys, as set by KEYCTL_SET_REQKEY_KEYRING.”h]”hŒ”If successful, the key will have been attached to the default keyring for
implicitly obtained request-key keys, as set by KEYCTL_SET_REQKEY_KEYRING.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MˆhjT  ubhÌ)”}”(hŒ5See also Documentation/security/keys/request-key.rst.”h]”hŒ5See also Documentation/security/keys/request-key.rst.”…””}”(hjž  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M‹hjT  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hX  To search for a key in a specific domain, call::

    struct key *request_key_tag(const struct key_type *type,
                                const char *description,
                                struct key_tag *domain_tag,
                                const char *callout_info);

This is identical to request_key(), except that a domain tag may be
specifies that causes search algorithm to only match keys matching that
tag.  The domain_tag may be NULL, specifying a global domain that is
separate from any nominated domain.

”h]”(hÌ)”}”(hŒ0To search for a key in a specific domain, call::”h]”hŒ/To search for a key in a specific domain, call:”…””}”(hj¶  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MŽhj²  ubjC	  )”}”(hŒÜstruct key *request_key_tag(const struct key_type *type,
                            const char *description,
                            struct key_tag *domain_tag,
                            const char *callout_info);”h]”hŒÜstruct key *request_key_tag(const struct key_type *type,
                            const char *description,
                            struct key_tag *domain_tag,
                            const char *callout_info);”…””}”hjÄ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhj²  ubhÌ)”}”(hŒôThis is identical to request_key(), except that a domain tag may be
specifies that causes search algorithm to only match keys matching that
tag.  The domain_tag may be NULL, specifying a global domain that is
separate from any nominated domain.”h]”hŒôThis is identical to request_key(), except that a domain tag may be
specifies that causes search algorithm to only match keys matching that
tag.  The domain_tag may be NULL, specifying a global domain that is
separate from any nominated domain.”…””}”(hjÒ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M•hj²  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hX   To search for a key, passing auxiliary data to the upcaller, call::

    struct key *request_key_with_auxdata(const struct key_type *type,
                                         const char *description,
                                         struct key_tag *domain_tag,
                                         const void *callout_info,
                                         size_t callout_len,
                                         void *aux);

This is identical to request_key_tag(), except that the auxiliary data is
passed to the key_type->request_key() op if it exists, and the
callout_info is a blob of length callout_len, if given (the length may be
0).

”h]”(hÌ)”}”(hŒCTo search for a key, passing auxiliary data to the upcaller, call::”h]”hŒBTo search for a key, passing auxiliary data to the upcaller, call:”…””}”(hjê  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M›hjæ  ubjC	  )”}”(hXi  struct key *request_key_with_auxdata(const struct key_type *type,
                                     const char *description,
                                     struct key_tag *domain_tag,
                                     const void *callout_info,
                                     size_t callout_len,
                                     void *aux);”h]”hXi  struct key *request_key_with_auxdata(const struct key_type *type,
                                     const char *description,
                                     struct key_tag *domain_tag,
                                     const void *callout_info,
                                     size_t callout_len,
                                     void *aux);”…””}”hjø  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhjæ  ubhÌ)”}”(hŒÖThis is identical to request_key_tag(), except that the auxiliary data is
passed to the key_type->request_key() op if it exists, and the
callout_info is a blob of length callout_len, if given (the length may be
0).”h]”hŒÖThis is identical to request_key_tag(), except that the auxiliary data is
passed to the key_type->request_key() op if it exists, and the
callout_info is a blob of length callout_len, if given (the length may be
0).”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¤hjæ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hX£  To search for a key under RCU conditions, call::

    struct key *request_key_rcu(const struct key_type *type,
                                const char *description,
                                struct key_tag *domain_tag);

which is similar to request_key_tag() except that it does not check for
keys that are under construction and it will not call out to userspace to
construct a key if it can't find a match.

”h]”(hÌ)”}”(hŒ0To search for a key under RCU conditions, call::”h]”hŒ/To search for a key under RCU conditions, call:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mªhj  ubjC	  )”}”(hŒ¦struct key *request_key_rcu(const struct key_type *type,
                            const char *description,
                            struct key_tag *domain_tag);”h]”hŒ¦struct key *request_key_rcu(const struct key_type *type,
                            const char *description,
                            struct key_tag *domain_tag);”…””}”hj,  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M¬hj  ubhÌ)”}”(hŒ»which is similar to request_key_tag() except that it does not check for
keys that are under construction and it will not call out to userspace to
construct a key if it can't find a match.”h]”hŒ½which is similar to request_key_tag() except that it does not check for
keys that are under construction and it will not call out to userspace to
construct a key if it canâ€™t find a match.”…””}”(hj:  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M°hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hX  When it is no longer required, the key should be released using::

    void key_put(struct key *key);

Or::

    void key_ref_put(key_ref_t key_ref);

These can be called from interrupt context. If CONFIG_KEYS is not set then
the argument will not be parsed.

”h]”(hÌ)”}”(hŒAWhen it is no longer required, the key should be released using::”h]”hŒ@When it is no longer required, the key should be released using:”…””}”(hjR  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MµhjN  ubjC	  )”}”(hŒvoid key_put(struct key *key);”h]”hŒvoid key_put(struct key *key);”…””}”hj`  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M·hjN  ubhÌ)”}”(hŒOr::”h]”hŒOr:”…””}”(hjn  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¹hjN  ubjC	  )”}”(hŒ$void key_ref_put(key_ref_t key_ref);”h]”hŒ$void key_ref_put(key_ref_t key_ref);”…””}”hj|  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M»hjN  ubhÌ)”}”(hŒkThese can be called from interrupt context. If CONFIG_KEYS is not set then
the argument will not be parsed.”h]”hŒkThese can be called from interrupt context. If CONFIG_KEYS is not set then
the argument will not be parsed.”…””}”(hjŠ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M½hjN  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hXÑ  Extra references can be made to a key by calling one of the following
functions::

    struct key *__key_get(struct key *key);
    struct key *key_get(struct key *key);

Keys so references will need to be disposed of by calling key_put() when
they've been finished with.  The key pointer passed in will be returned.

In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set
then the key will not be dereferenced and no increment will take place.

”h]”(hÌ)”}”(hŒQExtra references can be made to a key by calling one of the following
functions::”h]”hŒPExtra references can be made to a key by calling one of the following
functions:”…””}”(hj¢  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÁhjž  ubjC	  )”}”(hŒMstruct key *__key_get(struct key *key);
struct key *key_get(struct key *key);”h]”hŒMstruct key *__key_get(struct key *key);
struct key *key_get(struct key *key);”…””}”hj°  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MÄhjž  ubhÌ)”}”(hŒ‘Keys so references will need to be disposed of by calling key_put() when
they've been finished with.  The key pointer passed in will be returned.”h]”hŒ“Keys so references will need to be disposed of by calling key_put() when
theyâ€™ve been finished with.  The key pointer passed in will be returned.”…””}”(hj¾  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÇhjž  ubhÌ)”}”(hŒ’In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set
then the key will not be dereferenced and no increment will take place.”h]”hŒ’In the case of key_get(), if the pointer is NULL or CONFIG_KEYS is not set
then the key will not be dereferenced and no increment will take place.”…””}”(hjÌ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÊhjž  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hŒÛA key's serial number can be obtained by calling::

    key_serial_t key_serial(struct key *key);

If key is NULL or if CONFIG_KEYS is not set then 0 will be returned (in the
latter case without parsing the argument).

”h]”(hÌ)”}”(hŒ2A key's serial number can be obtained by calling::”h]”hŒ3A keyâ€™s serial number can be obtained by calling:”…””}”(hjä  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÎhjà  ubjC	  )”}”(hŒ)key_serial_t key_serial(struct key *key);”h]”hŒ)key_serial_t key_serial(struct key *key);”…””}”hjò  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MÐhjà  ubhÌ)”}”(hŒvIf key is NULL or if CONFIG_KEYS is not set then 0 will be returned (in the
latter case without parsing the argument).”h]”hŒvIf key is NULL or if CONFIG_KEYS is not set then 0 will be returned (in the
latter case without parsing the argument).”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÒhjà  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hXÌ  If a keyring was found in the search, this can be further searched by::

    key_ref_t keyring_search(key_ref_t keyring_ref,
                             const struct key_type *type,
                             const char *description,
                             bool recurse)

This searches the specified keyring only (recurse == false) or keyring tree
(recurse == true) specified for a matching key. Error ENOKEY is returned
upon failure (use IS_ERR/PTR_ERR to determine). If successful, the returned
key will need to be released.

The possession attribute from the keyring reference is used to control
access through the permissions mask and is propagated to the returned key
reference pointer if successful.

”h]”(hÌ)”}”(hŒGIf a keyring was found in the search, this can be further searched by::”h]”hŒFIf a keyring was found in the search, this can be further searched by:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÖhj  ubjC	  )”}”(hŒ¾key_ref_t keyring_search(key_ref_t keyring_ref,
                         const struct key_type *type,
                         const char *description,
                         bool recurse)”h]”hŒ¾key_ref_t keyring_search(key_ref_t keyring_ref,
                         const struct key_type *type,
                         const char *description,
                         bool recurse)”…””}”hj&  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MØhj  ubhÌ)”}”(hŒþThis searches the specified keyring only (recurse == false) or keyring tree
(recurse == true) specified for a matching key. Error ENOKEY is returned
upon failure (use IS_ERR/PTR_ERR to determine). If successful, the returned
key will need to be released.”h]”hŒþThis searches the specified keyring only (recurse == false) or keyring tree
(recurse == true) specified for a matching key. Error ENOKEY is returned
upon failure (use IS_ERR/PTR_ERR to determine). If successful, the returned
key will need to be released.”…””}”(hj4  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÝhj  ubhÌ)”}”(hŒ±The possession attribute from the keyring reference is used to control
access through the permissions mask and is propagated to the returned key
reference pointer if successful.”h]”hŒ±The possession attribute from the keyring reference is used to control
access through the permissions mask and is propagated to the returned key
reference pointer if successful.”…””}”(hjB  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mâhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hX  A keyring can be created by::

    struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
                              const struct cred *cred,
                              key_perm_t perm,
                              struct key_restriction *restrict_link,
                              unsigned long flags,
                              struct key *dest);

This creates a keyring with the given attributes and returns it.  If dest
is not NULL, the new keyring will be linked into the keyring to which it
points.  No permission checks are made upon the destination keyring.

Error EDQUOT can be returned if the keyring would overload the quota (pass
KEY_ALLOC_NOT_IN_QUOTA in flags if the keyring shouldn't be accounted
towards the user's quota).  Error ENOMEM can also be returned.

If restrict_link is not NULL, it should point to a structure that contains
the function that will be called each time an attempt is made to link a
key into the new keyring.  The structure may also contain a key pointer
and an associated key type.  The function is called to check whether a key
may be added into the keyring or not.  The key type is used by the garbage
collector to clean up function or data pointers in this structure if the
given key type is unregistered.  Callers of key_create_or_update() within
the kernel can pass KEY_ALLOC_BYPASS_RESTRICTION to suppress the check.
An example of using this is to manage rings of cryptographic keys that are
set up when the kernel boots where userspace is also permitted to add keys
- provided they can be verified by a key the kernel already has.

When called, the restriction function will be passed the keyring being
added to, the key type, the payload of the key being added, and data to be
used in the restriction check.  Note that when a new key is being created,
this is called between payload preparsing and actual key creation.  The
function should return 0 to allow the link or an error to reject it.

A convenience function, restrict_link_reject, exists to always return
-EPERM to in this case.

”h]”(hÌ)”}”(hŒA keyring can be created by::”h]”hŒA keyring can be created by:”…””}”(hjZ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MçhjV  ubjC	  )”}”(hXC  struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
                          const struct cred *cred,
                          key_perm_t perm,
                          struct key_restriction *restrict_link,
                          unsigned long flags,
                          struct key *dest);”h]”hXC  struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
                          const struct cred *cred,
                          key_perm_t perm,
                          struct key_restriction *restrict_link,
                          unsigned long flags,
                          struct key *dest);”…””}”hjh  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MéhjV  ubhÌ)”}”(hŒ×This creates a keyring with the given attributes and returns it.  If dest
is not NULL, the new keyring will be linked into the keyring to which it
points.  No permission checks are made upon the destination keyring.”h]”hŒ×This creates a keyring with the given attributes and returns it.  If dest
is not NULL, the new keyring will be linked into the keyring to which it
points.  No permission checks are made upon the destination keyring.”…””}”(hjv  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MðhjV  ubhÌ)”}”(hŒÏError EDQUOT can be returned if the keyring would overload the quota (pass
KEY_ALLOC_NOT_IN_QUOTA in flags if the keyring shouldn't be accounted
towards the user's quota).  Error ENOMEM can also be returned.”h]”hŒÓError EDQUOT can be returned if the keyring would overload the quota (pass
KEY_ALLOC_NOT_IN_QUOTA in flags if the keyring shouldnâ€™t be accounted
towards the userâ€™s quota).  Error ENOMEM can also be returned.”…””}”(hj„  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MôhjV  ubhÌ)”}”(hX"  If restrict_link is not NULL, it should point to a structure that contains
the function that will be called each time an attempt is made to link a
key into the new keyring.  The structure may also contain a key pointer
and an associated key type.  The function is called to check whether a key
may be added into the keyring or not.  The key type is used by the garbage
collector to clean up function or data pointers in this structure if the
given key type is unregistered.  Callers of key_create_or_update() within
the kernel can pass KEY_ALLOC_BYPASS_RESTRICTION to suppress the check.
An example of using this is to manage rings of cryptographic keys that are
set up when the kernel boots where userspace is also permitted to add keys
- provided they can be verified by a key the kernel already has.”h]”hX"  If restrict_link is not NULL, it should point to a structure that contains
the function that will be called each time an attempt is made to link a
key into the new keyring.  The structure may also contain a key pointer
and an associated key type.  The function is called to check whether a key
may be added into the keyring or not.  The key type is used by the garbage
collector to clean up function or data pointers in this structure if the
given key type is unregistered.  Callers of key_create_or_update() within
the kernel can pass KEY_ALLOC_BYPASS_RESTRICTION to suppress the check.
An example of using this is to manage rings of cryptographic keys that are
set up when the kernel boots where userspace is also permitted to add keys
- provided they can be verified by a key the kernel already has.”…””}”(hj’  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MøhjV  ubhÌ)”}”(hXi  When called, the restriction function will be passed the keyring being
added to, the key type, the payload of the key being added, and data to be
used in the restriction check.  Note that when a new key is being created,
this is called between payload preparsing and actual key creation.  The
function should return 0 to allow the link or an error to reject it.”h]”hXi  When called, the restriction function will be passed the keyring being
added to, the key type, the payload of the key being added, and data to be
used in the restriction check.  Note that when a new key is being created,
this is called between payload preparsing and actual key creation.  The
function should return 0 to allow the link or an error to reject it.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjV  ubhÌ)”}”(hŒ]A convenience function, restrict_link_reject, exists to always return
-EPERM to in this case.”h]”hŒ]A convenience function, restrict_link_reject, exists to always return
-EPERM to in this case.”…””}”(hj®  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M
hjV  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hX  To check the validity of a key, this function can be called::

    int validate_key(struct key *key);

This checks that the key in question hasn't expired or and hasn't been
revoked. Should the key be invalid, error EKEYEXPIRED or EKEYREVOKED will
be returned. If the key is NULL or if CONFIG_KEYS is not set then 0 will be
returned (in the latter case without parsing the argument).

”h]”(hÌ)”}”(hŒ=To check the validity of a key, this function can be called::”h]”hŒ<To check the validity of a key, this function can be called:”…””}”(hjÆ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÂ  ubjC	  )”}”(hŒ"int validate_key(struct key *key);”h]”hŒ"int validate_key(struct key *key);”…””}”hjÔ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MhjÂ  ubhÌ)”}”(hX  This checks that the key in question hasn't expired or and hasn't been
revoked. Should the key be invalid, error EKEYEXPIRED or EKEYREVOKED will
be returned. If the key is NULL or if CONFIG_KEYS is not set then 0 will be
returned (in the latter case without parsing the argument).”h]”hX  This checks that the key in question hasnâ€™t expired or and hasnâ€™t been
revoked. Should the key be invalid, error EKEYEXPIRED or EKEYREVOKED will
be returned. If the key is NULL or if CONFIG_KEYS is not set then 0 will be
returned (in the latter case without parsing the argument).”…””}”(hjâ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÂ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hŒÄTo register a key type, the following function should be called::

    int register_key_type(struct key_type *type);

This will return error EEXIST if a type of the same name is already
present.

”h]”(hÌ)”}”(hŒATo register a key type, the following function should be called::”h]”hŒ@To register a key type, the following function should be called:”…””}”(hjú  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjö  ubjC	  )”}”(hŒ-int register_key_type(struct key_type *type);”h]”hŒ-int register_key_type(struct key_type *type);”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhjö  ubhÌ)”}”(hŒLThis will return error EEXIST if a type of the same name is already
present.”h]”hŒLThis will return error EEXIST if a type of the same name is already
present.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjö  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubj*  )”}”(hŒXTo unregister a key type, call::

    void unregister_key_type(struct key_type *type);

”h]”(hÌ)”}”(hŒ To unregister a key type, call::”h]”hŒTo unregister a key type, call:”…””}”(hj.  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M hj*  ubjC	  )”}”(hŒ0void unregister_key_type(struct key_type *type);”h]”hŒ0void unregister_key_type(struct key_type *type);”…””}”hj<  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M"hj*  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjQ  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´MxhjM  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´Mxhj1  h²hubhÌ)”}”(hŒšUnder some circumstances, it may be desirable to deal with a bundle of keys.
The facility provides access to the keyring type for managing such a bundle::”h]”hŒ™Under some circumstances, it may be desirable to deal with a bundle of keys.
The facility provides access to the keyring type for managing such a bundle:”…””}”(hj\  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M%hj1  h²hubjC	  )”}”(hŒ!struct key_type key_type_keyring;”h]”hŒ!struct key_type key_type_keyring;”…””}”hjj  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M(hj1  h²hubhÌ)”}”(hX2  This can be used with a function such as request_key() to find a specific
keyring in a process's keyrings.  A keyring thus found can then be searched
with keyring_search().  Note that it is not possible to use request_key() to
search a specific keyring, so using keyrings in this way is of limited utility.”h]”hX4  This can be used with a function such as request_key() to find a specific
keyring in a processâ€™s keyrings.  A keyring thus found can then be searched
with keyring_search().  Note that it is not possible to use request_key() to
search a specific keyring, so using keyrings in this way is of limited utility.”…””}”(hjx  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M*hj1  h²hubeh}”(h]”j  ah ]”h"]”Œkernel services”ah$]”h&]”uh1hµhh·h²hh³hÊh´MCubh¶)”}”(hhh]”(h»)”}”(hŒ#Notes On Accessing Payload Contents”h]”hŒ#Notes On Accessing Payload Contents”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  j*  uh1hºhj  h²hh³hÊh´M1ubhÌ)”}”(hŒšThe simplest payload is just data stored in key->payload directly.  In this
case, there's no need to indulge in RCU or locking when accessing the payload.”h]”hŒœThe simplest payload is just data stored in key->payload directly.  In this
case, thereâ€™s no need to indulge in RCU or locking when accessing the payload.”…””}”(hjž  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M3hj  h²hubhÌ)”}”(hŒªMore complex payload contents must be allocated and pointers to them set in the
key->payload.data[] array.  One of the following ways must be selected to
access the data:”h]”hŒªMore complex payload contents must be allocated and pointers to them set in the
key->payload.data[] array.  One of the following ways must be selected to
access the data:”…””}”(hj¬  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M6hj  h²hubhø)”}”(hX·  1) Unmodifiable key type.

   If the key type does not have a modify method, then the key's payload can
   be accessed without any form of locking, provided that it's known to be
   instantiated (uninstantiated keys cannot be "found").

2) The key's semaphore.

   The semaphore could be used to govern access to the payload and to control
   the payload pointer. It must be write-locked for modifications and would
   have to be read-locked for general access. The disadvantage of doing this
   is that the accessor may be required to sleep.

3) RCU.

   RCU must be used when the semaphore isn't already held; if the semaphore
   is held then the contents can't change under you unexpectedly as the
   semaphore must still be used to serialise modifications to the key. The
   key management code takes care of this for the key type.

   However, this means using::

      rcu_read_lock() ... rcu_dereference() ... rcu_read_unlock()

   to read the pointer, and::

      rcu_dereference() ... rcu_assign_pointer() ... call_rcu()

   to set the pointer and dispose of the old contents after a grace period.
   Note that only the key type should ever modify a key's payload.

   Furthermore, an RCU controlled payload must hold a struct rcu_head for the
   use of call_rcu() and, if the payload is of variable size, the length of
   the payload. key->datalen cannot be relied upon to be consistent with the
   payload just dereferenced if the key's semaphore is not held.

   Note that key->payload.data[0] has a shadow that is marked for __rcu
   usage.  This is called key->payload.rcu_data0.  The following accessors
   wrap the RCU calls to this element:

   a) Set or change the first payload pointer::

              rcu_assign_keypointer(struct key *key, void *data);

   b) Read the first payload pointer with the key semaphore held::

              [const] void *dereference_key_locked([const] struct key *key);

       Note that the return value will inherit its constness from the key
       parameter.  Static analysis will give an error if it things the lock
       isn't held.

   c) Read the first payload pointer with the RCU read lock held::

              const void *dereference_key_rcu(const struct key *key);

”h]”hŒenumerated_list”“”)”}”(hhh]”(j*  )”}”(hŒàUnmodifiable key type.

If the key type does not have a modify method, then the key's payload can
be accessed without any form of locking, provided that it's known to be
instantiated (uninstantiated keys cannot be "found").
”h]”(hÌ)”}”(hŒUnmodifiable key type.”h]”hŒUnmodifiable key type.”…””}”(hjÇ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M:hjÃ  ubhÌ)”}”(hŒÇIf the key type does not have a modify method, then the key's payload can
be accessed without any form of locking, provided that it's known to be
instantiated (uninstantiated keys cannot be "found").”h]”hŒÏIf the key type does not have a modify method, then the keyâ€™s payload can
be accessed without any form of locking, provided that itâ€™s known to be
instantiated (uninstantiated keys cannot be â€œfoundâ€).”…””}”(hjÕ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M<hjÃ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjÀ  ubj*  )”}”(hX#  The key's semaphore.

The semaphore could be used to govern access to the payload and to control
the payload pointer. It must be write-locked for modifications and would
have to be read-locked for general access. The disadvantage of doing this
is that the accessor may be required to sleep.
”h]”(hÌ)”}”(hŒThe key's semaphore.”h]”hŒThe keyâ€™s semaphore.”…””}”(hjí  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M@hjé  ubhÌ)”}”(hX  The semaphore could be used to govern access to the payload and to control
the payload pointer. It must be write-locked for modifications and would
have to be read-locked for general access. The disadvantage of doing this
is that the accessor may be required to sleep.”h]”hX  The semaphore could be used to govern access to the payload and to control
the payload pointer. It must be write-locked for modifications and would
have to be read-locked for general access. The disadvantage of doing this
is that the accessor may be required to sleep.”…””}”(hjû  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MBhjé  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjÀ  ubj*  )”}”(hXF  RCU.

RCU must be used when the semaphore isn't already held; if the semaphore
is held then the contents can't change under you unexpectedly as the
semaphore must still be used to serialise modifications to the key. The
key management code takes care of this for the key type.

However, this means using::

   rcu_read_lock() ... rcu_dereference() ... rcu_read_unlock()

to read the pointer, and::

   rcu_dereference() ... rcu_assign_pointer() ... call_rcu()

to set the pointer and dispose of the old contents after a grace period.
Note that only the key type should ever modify a key's payload.

Furthermore, an RCU controlled payload must hold a struct rcu_head for the
use of call_rcu() and, if the payload is of variable size, the length of
the payload. key->datalen cannot be relied upon to be consistent with the
payload just dereferenced if the key's semaphore is not held.

Note that key->payload.data[0] has a shadow that is marked for __rcu
usage.  This is called key->payload.rcu_data0.  The following accessors
wrap the RCU calls to this element:

a) Set or change the first payload pointer::

           rcu_assign_keypointer(struct key *key, void *data);

b) Read the first payload pointer with the key semaphore held::

           [const] void *dereference_key_locked([const] struct key *key);

    Note that the return value will inherit its constness from the key
    parameter.  Static analysis will give an error if it things the lock
    isn't held.

c) Read the first payload pointer with the RCU read lock held::

           const void *dereference_key_rcu(const struct key *key);

”h]”(hÌ)”}”(hŒRCU.”h]”hŒRCU.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MGhj  ubhÌ)”}”(hX  RCU must be used when the semaphore isn't already held; if the semaphore
is held then the contents can't change under you unexpectedly as the
semaphore must still be used to serialise modifications to the key. The
key management code takes care of this for the key type.”h]”hX  RCU must be used when the semaphore isnâ€™t already held; if the semaphore
is held then the contents canâ€™t change under you unexpectedly as the
semaphore must still be used to serialise modifications to the key. The
key management code takes care of this for the key type.”…””}”(hj!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MIhj  ubhÌ)”}”(hŒHowever, this means using::”h]”hŒHowever, this means using:”…””}”(hj/  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MNhj  ubjC	  )”}”(hŒ;rcu_read_lock() ... rcu_dereference() ... rcu_read_unlock()”h]”hŒ;rcu_read_lock() ... rcu_dereference() ... rcu_read_unlock()”…””}”hj=  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MPhj  ubhÌ)”}”(hŒto read the pointer, and::”h]”hŒto read the pointer, and:”…””}”(hjK  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MRhj  ubjC	  )”}”(hŒ9rcu_dereference() ... rcu_assign_pointer() ... call_rcu()”h]”hŒ9rcu_dereference() ... rcu_assign_pointer() ... call_rcu()”…””}”hjY  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MThj  ubhÌ)”}”(hŒˆto set the pointer and dispose of the old contents after a grace period.
Note that only the key type should ever modify a key's payload.”h]”hŒŠto set the pointer and dispose of the old contents after a grace period.
Note that only the key type should ever modify a keyâ€™s payload.”…””}”(hjg  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MVhj  ubhÌ)”}”(hX  Furthermore, an RCU controlled payload must hold a struct rcu_head for the
use of call_rcu() and, if the payload is of variable size, the length of
the payload. key->datalen cannot be relied upon to be consistent with the
payload just dereferenced if the key's semaphore is not held.”h]”hX  Furthermore, an RCU controlled payload must hold a struct rcu_head for the
use of call_rcu() and, if the payload is of variable size, the length of
the payload. key->datalen cannot be relied upon to be consistent with the
payload just dereferenced if the keyâ€™s semaphore is not held.”…””}”(hju  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MYhj  ubhÌ)”}”(hŒ°Note that key->payload.data[0] has a shadow that is marked for __rcu
usage.  This is called key->payload.rcu_data0.  The following accessors
wrap the RCU calls to this element:”h]”hŒ°Note that key->payload.data[0] has a shadow that is marked for __rcu
usage.  This is called key->payload.rcu_data0.  The following accessors
wrap the RCU calls to this element:”…””}”(hjƒ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M^hj  ubj¿  )”}”(hhh]”(j*  )”}”(hŒgSet or change the first payload pointer::

        rcu_assign_keypointer(struct key *key, void *data);
”h]”(hÌ)”}”(hŒ)Set or change the first payload pointer::”h]”hŒ(Set or change the first payload pointer:”…””}”(hj˜  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mbhj”  ubjC	  )”}”(hŒ3rcu_assign_keypointer(struct key *key, void *data);”h]”hŒ3rcu_assign_keypointer(struct key *key, void *data);”…””}”hj¦  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mdhj”  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj‘  ubj*  )”}”(hX  Read the first payload pointer with the key semaphore held::

        [const] void *dereference_key_locked([const] struct key *key);

 Note that the return value will inherit its constness from the key
 parameter.  Static analysis will give an error if it things the lock
 isn't held.
”h]”(hÌ)”}”(hŒ<Read the first payload pointer with the key semaphore held::”h]”hŒ;Read the first payload pointer with the key semaphore held:”…””}”(hj¾  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mfhjº  ubjC	  )”}”(hŒÚ       [const] void *dereference_key_locked([const] struct key *key);

Note that the return value will inherit its constness from the key
parameter.  Static analysis will give an error if it things the lock
isn't held.”h]”hŒÚ       [const] void *dereference_key_locked([const] struct key *key);

Note that the return value will inherit its constness from the key
parameter.  Static analysis will give an error if it things the lock
isn't held.”…””}”hjÌ  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhhjº  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj‘  ubj*  )”}”(hŒRead the first payload pointer with the RCU read lock held::

        const void *dereference_key_rcu(const struct key *key);

”h]”(hÌ)”}”(hŒ<Read the first payload pointer with the RCU read lock held::”h]”hŒ;Read the first payload pointer with the RCU read lock held:”…””}”(hjä  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mnhjà  ubjC	  )”}”(hŒ7const void *dereference_key_rcu(const struct key *key);”h]”hŒ7const void *dereference_key_rcu(const struct key *key);”…””}”hjò  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mphjà  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj‘  ubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œ
loweralpha”Œprefix”hŒsuffix”Œ)”uh1j¾  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjÀ  ubeh}”(h]”h ]”h"]”h$]”h&]”j  Œarabic”j  hj  j  uh1j¾  hjº  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M:hj  h²hubeh}”(h]”j0  ah ]”h"]”Œ#notes on accessing payload contents”ah$]”h&]”uh1hµhh·h²hh³hÊh´M1ubh¶)”}”(hhh]”(h»)”}”(hŒDefining a Key Type”h]”hŒDefining a Key Type”…””}”(hj.  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  jL  uh1hºhj+  h²hh³hÊh´MtubhÌ)”}”(hŒÛA kernel service may want to define its own key type. For instance, an AFS
filesystem might want to define a Kerberos 5 ticket key type. To do this, it
author fills in a key_type struct and registers it with the system.”h]”hŒÛA kernel service may want to define its own key type. For instance, an AFS
filesystem might want to define a Kerberos 5 ticket key type. To do this, it
author fills in a key_type struct and registers it with the system.”…””}”(hj<  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mvhj+  h²hubhÌ)”}”(hŒPSource files that implement key types should include the following header file::”h]”hŒOSource files that implement key types should include the following header file:”…””}”(hjJ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mzhj+  h²hubjC	  )”}”(hŒ<linux/key-type.h>”h]”hŒ<linux/key-type.h>”…””}”hjX  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M|hj+  h²hubhÌ)”}”(hŒBThe structure has a number of fields, some of which are mandatory:”h]”hŒBThe structure has a number of fields, some of which are mandatory:”…””}”(hjf  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M~hj+  h²hubhø)”}”(hX6>  *  ``const char *name``

   The name of the key type. This is used to translate a key type name
   supplied by userspace into a pointer to the structure.


*  ``size_t def_datalen``

   This is optional - it supplies the default payload data length as
   contributed to the quota. If the key type's payload is always or almost
   always the same size, then this is a more efficient way to do things.

   The data length (and quota) on a particular key can always be changed
   during instantiation or update by calling::

      int key_payload_reserve(struct key *key, size_t datalen);

   With the revised data length. Error EDQUOT will be returned if this is not
   viable.


*  ``int (*vet_description)(const char *description);``

   This optional method is called to vet a key description.  If the key type
   doesn't approve of the key description, it may return an error, otherwise
   it should return 0.


*  ``int (*preparse)(struct key_preparsed_payload *prep);``

   This optional method permits the key type to attempt to parse payload
   before a key is created (add key) or the key semaphore is taken (update or
   instantiate key).  The structure pointed to by prep looks like::

      struct key_preparsed_payload {
              char            *description;
              union key_payload payload;
              const void      *data;
              size_t          datalen;
              size_t          quotalen;
              time_t          expiry;
      };

   Before calling the method, the caller will fill in data and datalen with
   the payload blob parameters; quotalen will be filled in with the default
   quota size from the key type; expiry will be set to TIME_T_MAX and the
   rest will be cleared.

   If a description can be proposed from the payload contents, that should be
   attached as a string to the description field.  This will be used for the
   key description if the caller of add_key() passes NULL or "".

   The method can attach anything it likes to payload.  This is merely passed
   along to the instantiate() or update() operations.  If set, the expiry
   time will be applied to the key if it is instantiated from this data.

   The method should return 0 if successful or a negative error code
   otherwise.


*  ``void (*free_preparse)(struct key_preparsed_payload *prep);``

   This method is only required if the preparse() method is provided,
   otherwise it is unused.  It cleans up anything attached to the description
   and payload fields of the key_preparsed_payload struct as filled in by the
   preparse() method.  It will always be called after preparse() returns
   successfully, even if instantiate() or update() succeed.


*  ``int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);``

   This method is called to attach a payload to a key during construction.
   The payload attached need not bear any relation to the data passed to this
   function.

   The prep->data and prep->datalen fields will define the original payload
   blob.  If preparse() was supplied then other fields may be filled in also.

   If the amount of data attached to the key differs from the size in
   keytype->def_datalen, then key_payload_reserve() should be called.

   This method does not have to lock the key in order to attach a payload.
   The fact that KEY_FLAG_INSTANTIATED is not set in key->flags prevents
   anything else from gaining access to the key.

   It is safe to sleep in this method.

   generic_key_instantiate() is provided to simply copy the data from
   prep->payload.data[] to key->payload.data[], with RCU-safe assignment on
   the first element.  It will then clear prep->payload.data[] so that the
   free_preparse method doesn't release the data.


*  ``int (*update)(struct key *key, const void *data, size_t datalen);``

   If this type of key can be updated, then this method should be provided.
   It is called to update a key's payload from the blob of data provided.

   The prep->data and prep->datalen fields will define the original payload
   blob.  If preparse() was supplied then other fields may be filled in also.

   key_payload_reserve() should be called if the data length might change
   before any changes are actually made. Note that if this succeeds, the type
   is committed to changing the key because it's already been altered, so all
   memory allocation must be done first.

   The key will have its semaphore write-locked before this method is called,
   but this only deters other writers; any changes to the key's payload must
   be made under RCU conditions, and call_rcu() must be used to dispose of
   the old payload.

   key_payload_reserve() should be called before the changes are made, but
   after all allocations and other potentially failing function calls are
   made.

   It is safe to sleep in this method.


*  ``int (*match_preparse)(struct key_match_data *match_data);``

   This method is optional.  It is called when a key search is about to be
   performed.  It is given the following structure::

      struct key_match_data {
              bool (*cmp)(const struct key *key,
                          const struct key_match_data *match_data);
              const void      *raw_data;
              void            *preparsed;
              unsigned        lookup_type;
      };

   On entry, raw_data will be pointing to the criteria to be used in matching
   a key by the caller and should not be modified.  ``(*cmp)()`` will be pointing
   to the default matcher function (which does an exact description match
   against raw_data) and lookup_type will be set to indicate a direct lookup.

   The following lookup_type values are available:

     *  KEYRING_SEARCH_LOOKUP_DIRECT - A direct lookup hashes the type and
        description to narrow down the search to a small number of keys.

     *  KEYRING_SEARCH_LOOKUP_ITERATE - An iterative lookup walks all the
        keys in the keyring until one is matched.  This must be used for any
        search that's not doing a simple direct match on the key description.

   The method may set cmp to point to a function of its choice that does some
   other form of match, may set lookup_type to KEYRING_SEARCH_LOOKUP_ITERATE
   and may attach something to the preparsed pointer for use by ``(*cmp)()``.
   ``(*cmp)()`` should return true if a key matches and false otherwise.

   If preparsed is set, it may be necessary to use the match_free() method to
   clean it up.

   The method should return 0 if successful or a negative error code
   otherwise.

   It is permitted to sleep in this method, but ``(*cmp)()`` may not sleep as
   locks will be held over it.

   If match_preparse() is not provided, keys of this type will be matched
   exactly by their description.


*  ``void (*match_free)(struct key_match_data *match_data);``

   This method is optional.  If given, it called to clean up
   match_data->preparsed after a successful call to match_preparse().


*  ``void (*revoke)(struct key *key);``

   This method is optional.  It is called to discard part of the payload
   data upon a key being revoked.  The caller will have the key semaphore
   write-locked.

   It is safe to sleep in this method, though care should be taken to avoid
   a deadlock against the key semaphore.


*  ``void (*destroy)(struct key *key);``

   This method is optional. It is called to discard the payload data on a key
   when it is being destroyed.

   This method does not need to lock the key to access the payload; it can
   consider the key as being inaccessible at this time. Note that the key's
   type may have been changed before this function is called.

   It is not safe to sleep in this method; the caller may hold spinlocks.


*  ``void (*describe)(const struct key *key, struct seq_file *p);``

   This method is optional. It is called during /proc/keys reading to
   summarise a key's description and payload in text form.

   This method will be called with the RCU read lock held. rcu_dereference()
   should be used to read the payload pointer if the payload is to be
   accessed. key->datalen cannot be trusted to stay consistent with the
   contents of the payload.

   The description will not change, though the key's state may.

   It is not safe to sleep in this method; the RCU read lock is held by the
   caller.


*  ``long (*read)(const struct key *key, char __user *buffer, size_t buflen);``

   This method is optional. It is called by KEYCTL_READ to translate the
   key's payload into something a blob of data for userspace to deal with.
   Ideally, the blob should be in the same format as that passed in to the
   instantiate and update methods.

   If successful, the blob size that could be produced should be returned
   rather than the size copied.

   This method will be called with the key's semaphore read-locked. This will
   prevent the key's payload changing. It is not necessary to use RCU locking
   when accessing the key's payload. It is safe to sleep in this method, such
   as might happen when the userspace buffer is accessed.


*  ``int (*request_key)(struct key_construction *cons, const char *op, void *aux);``

   This method is optional.  If provided, request_key() and friends will
   invoke this function rather than upcalling to /sbin/request-key to operate
   upon a key of this type.

   The aux parameter is as passed to request_key_async_with_auxdata() and
   similar or is NULL otherwise.  Also passed are the construction record for
   the key to be operated upon and the operation type (currently only
   "create").

   This method is permitted to return before the upcall is complete, but the
   following function must be called under all circumstances to complete the
   instantiation process, whether or not it succeeds, whether or not there's
   an error::

      void complete_request_key(struct key_construction *cons, int error);

   The error parameter should be 0 on success, -ve on error.  The
   construction record is destroyed by this action and the authorisation key
   will be revoked.  If an error is indicated, the key under construction
   will be negatively instantiated if it wasn't already instantiated.

   If this method returns an error, that error will be returned to the
   caller of request_key*().  complete_request_key() must be called prior to
   returning.

   The key under construction and the authorisation key can be found in the
   key_construction struct pointed to by cons:

    *  ``struct key *key;``

       The key under construction.

    *  ``struct key *authkey;``

       The authorisation key.


*  ``struct key_restriction *(*lookup_restriction)(const char *params);``

   This optional method is used to enable userspace configuration of keyring
   restrictions. The restriction parameter string (not including the key type
   name) is passed in, and this method returns a pointer to a key_restriction
   structure containing the relevant functions and data to evaluate each
   attempted key link operation. If there is no match, -EINVAL is returned.


*  ``asym_eds_op`` and ``asym_verify_signature``::

     int (*asym_eds_op)(struct kernel_pkey_params *params,
                        const void *in, void *out);
     int (*asym_verify_signature)(struct kernel_pkey_params *params,
                                  const void *in, const void *in2);

   These methods are optional.  If provided the first allows a key to be
   used to encrypt, decrypt or sign a blob of data, and the second allows a
   key to verify a signature.

   In all cases, the following information is provided in the params block::

      struct kernel_pkey_params {
              struct key      *key;
              const char      *encoding;
              const char      *hash_algo;
              char            *info;
              __u32           in_len;
              union {
                      __u32   out_len;
                      __u32   in2_len;
              };
              enum kernel_pkey_operation op : 8;
      };

   This includes the key to be used; a string indicating the encoding to use
   (for instance, "pkcs1" may be used with an RSA key to indicate
   RSASSA-PKCS1-v1.5 or RSAES-PKCS1-v1.5 encoding or "raw" if no encoding);
   the name of the hash algorithm used to generate the data for a signature
   (if appropriate); the sizes of the input and output (or second input)
   buffers; and the ID of the operation to be performed.

   For a given operation ID, the input and output buffers are used as
   follows::

      Operation ID            in,in_len       out,out_len     in2,in2_len
      ======================= =============== =============== ===============
      kernel_pkey_encrypt     Raw data        Encrypted data  -
      kernel_pkey_decrypt     Encrypted data  Raw data        -
      kernel_pkey_sign        Raw data        Signature       -
      kernel_pkey_verify      Raw data        -               Signature

   asym_eds_op() deals with encryption, decryption and signature creation as
   specified by params->op.  Note that params->op is also set for
   asym_verify_signature().

   Encrypting and signature creation both take raw data in the input buffer
   and return the encrypted result in the output buffer.  Padding may have
   been added if an encoding was set.  In the case of signature creation,
   depending on the encoding, the padding created may need to indicate the
   digest algorithm - the name of which should be supplied in hash_algo.

   Decryption takes encrypted data in the input buffer and returns the raw
   data in the output buffer.  Padding will get checked and stripped off if
   an encoding was set.

   Verification takes raw data in the input buffer and the signature in the
   second input buffer and checks that the one matches the other.  Padding
   will be validated.  Depending on the encoding, the digest algorithm used
   to generate the raw data may need to be indicated in hash_algo.

   If successful, asym_eds_op() should return the number of bytes written
   into the output buffer.  asym_verify_signature() should return 0.

   A variety of errors may be returned, including EOPNOTSUPP if the operation
   is not supported; EKEYREJECTED if verification fails; ENOPKG if the
   required crypto isn't available.


*  ``asym_query``::

     int (*asym_query)(const struct kernel_pkey_params *params,
                       struct kernel_pkey_query *info);

   This method is optional.  If provided it allows information about the
   public or asymmetric key held in the key to be determined.

   The parameter block is as for asym_eds_op() and co. but in_len and out_len
   are unused.  The encoding and hash_algo fields should be used to reduce
   the returned buffer/data sizes as appropriate.

   If successful, the following information is filled in::

      struct kernel_pkey_query {
              __u32           supported_ops;
              __u32           key_size;
              __u16           max_data_size;
              __u16           max_sig_size;
              __u16           max_enc_size;
              __u16           max_dec_size;
      };

   The supported_ops field will contain a bitmask indicating what operations
   are supported by the key, including encryption of a blob, decryption of a
   blob, signing a blob and verifying the signature on a blob.  The following
   constants are defined for this::

      KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}

   The key_size field is the size of the key in bits.  max_data_size and
   max_sig_size are the maximum raw data and signature sizes for creation and
   verification of a signature; max_enc_size and max_dec_size are the maximum
   raw data and signature sizes for encryption and decryption.  The
   max_*_size fields are measured in bytes.

   If successful, 0 will be returned.  If the key doesn't support this,
   EOPNOTSUPP will be returned.

”•‹      h]”j%  )”}”(hhh]”(j*  )”}”(hŒ’``const char *name``

The name of the key type. This is used to translate a key type name
supplied by userspace into a pointer to the structure.

”h]”(hÌ)”}”(hŒ``const char *name``”h]”jª  )”}”(hj  h]”hŒconst char *name”…””}”(hjƒ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M€hj{  ubhÌ)”}”(hŒzThe name of the key type. This is used to translate a key type name
supplied by userspace into a pointer to the structure.”h]”hŒzThe name of the key type. This is used to translate a key type name
supplied by userspace into a pointer to the structure.”…””}”(hj–  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M‚hj{  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hXî  ``size_t def_datalen``

This is optional - it supplies the default payload data length as
contributed to the quota. If the key type's payload is always or almost
always the same size, then this is a more efficient way to do things.

The data length (and quota) on a particular key can always be changed
during instantiation or update by calling::

   int key_payload_reserve(struct key *key, size_t datalen);

With the revised data length. Error EDQUOT will be returned if this is not
viable.

”h]”(hÌ)”}”(hŒ``size_t def_datalen``”h]”jª  )”}”(hj°  h]”hŒsize_t def_datalen”…””}”(hj²  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj®  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M†hjª  ubhÌ)”}”(hŒÏThis is optional - it supplies the default payload data length as
contributed to the quota. If the key type's payload is always or almost
always the same size, then this is a more efficient way to do things.”h]”hŒÑThis is optional - it supplies the default payload data length as
contributed to the quota. If the key typeâ€™s payload is always or almost
always the same size, then this is a more efficient way to do things.”…””}”(hjÅ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mˆhjª  ubhÌ)”}”(hŒqThe data length (and quota) on a particular key can always be changed
during instantiation or update by calling::”h]”hŒpThe data length (and quota) on a particular key can always be changed
during instantiation or update by calling:”…””}”(hjÓ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MŒhjª  ubjC	  )”}”(hŒ9int key_payload_reserve(struct key *key, size_t datalen);”h]”hŒ9int key_payload_reserve(struct key *key, size_t datalen);”…””}”hjá  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhjª  ubhÌ)”}”(hŒRWith the revised data length. Error EDQUOT will be returned if this is not
viable.”h]”hŒRWith the revised data length. Error EDQUOT will be returned if this is not
viable.”…””}”(hjï  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M‘hjª  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hŒß``int (*vet_description)(const char *description);``

This optional method is called to vet a key description.  If the key type
doesn't approve of the key description, it may return an error, otherwise
it should return 0.

”h]”(hÌ)”}”(hŒ4``int (*vet_description)(const char *description);``”h]”jª  )”}”(hj	  h]”hŒ0int (*vet_description)(const char *description);”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M•hj  ubhÌ)”}”(hŒ§This optional method is called to vet a key description.  If the key type
doesn't approve of the key description, it may return an error, otherwise
it should return 0.”h]”hŒ©This optional method is called to vet a key description.  If the key type
doesnâ€™t approve of the key description, it may return an error, otherwise
it should return 0.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M—hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hXþ  ``int (*preparse)(struct key_preparsed_payload *prep);``

This optional method permits the key type to attempt to parse payload
before a key is created (add key) or the key semaphore is taken (update or
instantiate key).  The structure pointed to by prep looks like::

   struct key_preparsed_payload {
           char            *description;
           union key_payload payload;
           const void      *data;
           size_t          datalen;
           size_t          quotalen;
           time_t          expiry;
   };

Before calling the method, the caller will fill in data and datalen with
the payload blob parameters; quotalen will be filled in with the default
quota size from the key type; expiry will be set to TIME_T_MAX and the
rest will be cleared.

If a description can be proposed from the payload contents, that should be
attached as a string to the description field.  This will be used for the
key description if the caller of add_key() passes NULL or "".

The method can attach anything it likes to payload.  This is merely passed
along to the instantiate() or update() operations.  If set, the expiry
time will be applied to the key if it is instantiated from this data.

The method should return 0 if successful or a negative error code
otherwise.

”h]”(hÌ)”}”(hŒ8``int (*preparse)(struct key_preparsed_payload *prep);``”h]”jª  )”}”(hj8  h]”hŒ4int (*preparse)(struct key_preparsed_payload *prep);”…””}”(hj:  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj6  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mœhj2  ubhÌ)”}”(hŒÑThis optional method permits the key type to attempt to parse payload
before a key is created (add key) or the key semaphore is taken (update or
instantiate key).  The structure pointed to by prep looks like::”h]”hŒÐThis optional method permits the key type to attempt to parse payload
before a key is created (add key) or the key semaphore is taken (update or
instantiate key).  The structure pointed to by prep looks like:”…””}”(hjM  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mžhj2  ubjC	  )”}”(hŒìstruct key_preparsed_payload {
        char            *description;
        union key_payload payload;
        const void      *data;
        size_t          datalen;
        size_t          quotalen;
        time_t          expiry;
};”h]”hŒìstruct key_preparsed_payload {
        char            *description;
        union key_payload payload;
        const void      *data;
        size_t          datalen;
        size_t          quotalen;
        time_t          expiry;
};”…””}”hj[  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M¢hj2  ubhÌ)”}”(hŒîBefore calling the method, the caller will fill in data and datalen with
the payload blob parameters; quotalen will be filled in with the default
quota size from the key type; expiry will be set to TIME_T_MAX and the
rest will be cleared.”h]”hŒîBefore calling the method, the caller will fill in data and datalen with
the payload blob parameters; quotalen will be filled in with the default
quota size from the key type; expiry will be set to TIME_T_MAX and the
rest will be cleared.”…””}”(hji  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M«hj2  ubhÌ)”}”(hŒÒIf a description can be proposed from the payload contents, that should be
attached as a string to the description field.  This will be used for the
key description if the caller of add_key() passes NULL or "".”h]”hŒÖIf a description can be proposed from the payload contents, that should be
attached as a string to the description field.  This will be used for the
key description if the caller of add_key() passes NULL or â€œâ€.”…””}”(hjw  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M°hj2  ubhÌ)”}”(hŒ×The method can attach anything it likes to payload.  This is merely passed
along to the instantiate() or update() operations.  If set, the expiry
time will be applied to the key if it is instantiated from this data.”h]”hŒ×The method can attach anything it likes to payload.  This is merely passed
along to the instantiate() or update() operations.  If set, the expiry
time will be applied to the key if it is instantiated from this data.”…””}”(hj…  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M´hj2  ubhÌ)”}”(hŒLThe method should return 0 if successful or a negative error code
otherwise.”h]”hŒLThe method should return 0 if successful or a negative error code
otherwise.”…””}”(hj“  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¸hj2  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX™  ``void (*free_preparse)(struct key_preparsed_payload *prep);``

This method is only required if the preparse() method is provided,
otherwise it is unused.  It cleans up anything attached to the description
and payload fields of the key_preparsed_payload struct as filled in by the
preparse() method.  It will always be called after preparse() returns
successfully, even if instantiate() or update() succeed.

”h]”(hÌ)”}”(hŒ>``void (*free_preparse)(struct key_preparsed_payload *prep);``”h]”jª  )”}”(hj­  h]”hŒ:void (*free_preparse)(struct key_preparsed_payload *prep);”…””}”(hj¯  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj«  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¼hj§  ubhÌ)”}”(hXW  This method is only required if the preparse() method is provided,
otherwise it is unused.  It cleans up anything attached to the description
and payload fields of the key_preparsed_payload struct as filled in by the
preparse() method.  It will always be called after preparse() returns
successfully, even if instantiate() or update() succeed.”h]”hXW  This method is only required if the preparse() method is provided,
otherwise it is unused.  It cleans up anything attached to the description
and payload fields of the key_preparsed_payload struct as filled in by the
preparse() method.  It will always be called after preparse() returns
successfully, even if instantiate() or update() succeed.”…””}”(hjÂ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¾hj§  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hXî  ``int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);``

This method is called to attach a payload to a key during construction.
The payload attached need not bear any relation to the data passed to this
function.

The prep->data and prep->datalen fields will define the original payload
blob.  If preparse() was supplied then other fields may be filled in also.

If the amount of data attached to the key differs from the size in
keytype->def_datalen, then key_payload_reserve() should be called.

This method does not have to lock the key in order to attach a payload.
The fact that KEY_FLAG_INSTANTIATED is not set in key->flags prevents
anything else from gaining access to the key.

It is safe to sleep in this method.

generic_key_instantiate() is provided to simply copy the data from
prep->payload.data[] to key->payload.data[], with RCU-safe assignment on
the first element.  It will then clear prep->payload.data[] so that the
free_preparse method doesn't release the data.

”h]”(hÌ)”}”(hŒL``int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);``”h]”jª  )”}”(hjÜ  h]”hŒHint (*instantiate)(struct key *key, struct key_preparsed_payload *prep);”…””}”(hjÞ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjÚ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÅhjÖ  ubhÌ)”}”(hŒœThis method is called to attach a payload to a key during construction.
The payload attached need not bear any relation to the data passed to this
function.”h]”hŒœThis method is called to attach a payload to a key during construction.
The payload attached need not bear any relation to the data passed to this
function.”…””}”(hjñ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÇhjÖ  ubhÌ)”}”(hŒ“The prep->data and prep->datalen fields will define the original payload
blob.  If preparse() was supplied then other fields may be filled in also.”h]”hŒ“The prep->data and prep->datalen fields will define the original payload
blob.  If preparse() was supplied then other fields may be filled in also.”…””}”(hjÿ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MËhjÖ  ubhÌ)”}”(hŒ…If the amount of data attached to the key differs from the size in
keytype->def_datalen, then key_payload_reserve() should be called.”h]”hŒ…If the amount of data attached to the key differs from the size in
keytype->def_datalen, then key_payload_reserve() should be called.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÎhjÖ  ubhÌ)”}”(hŒ»This method does not have to lock the key in order to attach a payload.
The fact that KEY_FLAG_INSTANTIATED is not set in key->flags prevents
anything else from gaining access to the key.”h]”hŒ»This method does not have to lock the key in order to attach a payload.
The fact that KEY_FLAG_INSTANTIATED is not set in key->flags prevents
anything else from gaining access to the key.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÑhjÖ  ubhÌ)”}”(hŒ#It is safe to sleep in this method.”h]”hŒ#It is safe to sleep in this method.”…””}”(hj)   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÕhjÖ  ubhÌ)”}”(hX  generic_key_instantiate() is provided to simply copy the data from
prep->payload.data[] to key->payload.data[], with RCU-safe assignment on
the first element.  It will then clear prep->payload.data[] so that the
free_preparse method doesn't release the data.”h]”hX  generic_key_instantiate() is provided to simply copy the data from
prep->payload.data[] to key->payload.data[], with RCU-safe assignment on
the first element.  It will then clear prep->payload.data[] so that the
free_preparse method doesnâ€™t release the data.”…””}”(hj7   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M×hjÖ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX  ``int (*update)(struct key *key, const void *data, size_t datalen);``

If this type of key can be updated, then this method should be provided.
It is called to update a key's payload from the blob of data provided.

The prep->data and prep->datalen fields will define the original payload
blob.  If preparse() was supplied then other fields may be filled in also.

key_payload_reserve() should be called if the data length might change
before any changes are actually made. Note that if this succeeds, the type
is committed to changing the key because it's already been altered, so all
memory allocation must be done first.

The key will have its semaphore write-locked before this method is called,
but this only deters other writers; any changes to the key's payload must
be made under RCU conditions, and call_rcu() must be used to dispose of
the old payload.

key_payload_reserve() should be called before the changes are made, but
after all allocations and other potentially failing function calls are
made.

It is safe to sleep in this method.

”h]”(hÌ)”}”(hŒE``int (*update)(struct key *key, const void *data, size_t datalen);``”h]”jª  )”}”(hjQ   h]”hŒAint (*update)(struct key *key, const void *data, size_t datalen);”…””}”(hjS   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjO   ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÝhjK   ubhÌ)”}”(hŒIf this type of key can be updated, then this method should be provided.
It is called to update a key's payload from the blob of data provided.”h]”hŒ‘If this type of key can be updated, then this method should be provided.
It is called to update a keyâ€™s payload from the blob of data provided.”…””}”(hjf   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MßhjK   ubhÌ)”}”(hŒ“The prep->data and prep->datalen fields will define the original payload
blob.  If preparse() was supplied then other fields may be filled in also.”h]”hŒ“The prep->data and prep->datalen fields will define the original payload
blob.  If preparse() was supplied then other fields may be filled in also.”…””}”(hjt   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MâhjK   ubhÌ)”}”(hX  key_payload_reserve() should be called if the data length might change
before any changes are actually made. Note that if this succeeds, the type
is committed to changing the key because it's already been altered, so all
memory allocation must be done first.”h]”hX  key_payload_reserve() should be called if the data length might change
before any changes are actually made. Note that if this succeeds, the type
is committed to changing the key because itâ€™s already been altered, so all
memory allocation must be done first.”…””}”(hj‚   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MåhjK   ubhÌ)”}”(hŒíThe key will have its semaphore write-locked before this method is called,
but this only deters other writers; any changes to the key's payload must
be made under RCU conditions, and call_rcu() must be used to dispose of
the old payload.”h]”hŒïThe key will have its semaphore write-locked before this method is called,
but this only deters other writers; any changes to the keyâ€™s payload must
be made under RCU conditions, and call_rcu() must be used to dispose of
the old payload.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MêhjK   ubhÌ)”}”(hŒ”key_payload_reserve() should be called before the changes are made, but
after all allocations and other potentially failing function calls are
made.”h]”hŒ”key_payload_reserve() should be called before the changes are made, but
after all allocations and other potentially failing function calls are
made.”…””}”(hjž   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MïhjK   ubhÌ)”}”(hŒ#It is safe to sleep in this method.”h]”hŒ#It is safe to sleep in this method.”…””}”(hj¬   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MóhjK   ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX&  ``int (*match_preparse)(struct key_match_data *match_data);``

This method is optional.  It is called when a key search is about to be
performed.  It is given the following structure::

   struct key_match_data {
           bool (*cmp)(const struct key *key,
                       const struct key_match_data *match_data);
           const void      *raw_data;
           void            *preparsed;
           unsigned        lookup_type;
   };

On entry, raw_data will be pointing to the criteria to be used in matching
a key by the caller and should not be modified.  ``(*cmp)()`` will be pointing
to the default matcher function (which does an exact description match
against raw_data) and lookup_type will be set to indicate a direct lookup.

The following lookup_type values are available:

  *  KEYRING_SEARCH_LOOKUP_DIRECT - A direct lookup hashes the type and
     description to narrow down the search to a small number of keys.

  *  KEYRING_SEARCH_LOOKUP_ITERATE - An iterative lookup walks all the
     keys in the keyring until one is matched.  This must be used for any
     search that's not doing a simple direct match on the key description.

The method may set cmp to point to a function of its choice that does some
other form of match, may set lookup_type to KEYRING_SEARCH_LOOKUP_ITERATE
and may attach something to the preparsed pointer for use by ``(*cmp)()``.
``(*cmp)()`` should return true if a key matches and false otherwise.

If preparsed is set, it may be necessary to use the match_free() method to
clean it up.

The method should return 0 if successful or a negative error code
otherwise.

It is permitted to sleep in this method, but ``(*cmp)()`` may not sleep as
locks will be held over it.

If match_preparse() is not provided, keys of this type will be matched
exactly by their description.

”h]”(hÌ)”}”(hŒ=``int (*match_preparse)(struct key_match_data *match_data);``”h]”jª  )”}”(hjÆ   h]”hŒ9int (*match_preparse)(struct key_match_data *match_data);”…””}”(hjÈ   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjÄ   ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MöhjÀ   ubhÌ)”}”(hŒyThis method is optional.  It is called when a key search is about to be
performed.  It is given the following structure::”h]”hŒxThis method is optional.  It is called when a key search is about to be
performed.  It is given the following structure:”…””}”(hjÛ   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MøhjÀ   ubjC	  )”}”(hŒïstruct key_match_data {
        bool (*cmp)(const struct key *key,
                    const struct key_match_data *match_data);
        const void      *raw_data;
        void            *preparsed;
        unsigned        lookup_type;
};”h]”hŒïstruct key_match_data {
        bool (*cmp)(const struct key *key,
                    const struct key_match_data *match_data);
        const void      *raw_data;
        void            *preparsed;
        unsigned        lookup_type;
};”…””}”hjé   sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MûhjÀ   ubhÌ)”}”(hX+  On entry, raw_data will be pointing to the criteria to be used in matching
a key by the caller and should not be modified.  ``(*cmp)()`` will be pointing
to the default matcher function (which does an exact description match
against raw_data) and lookup_type will be set to indicate a direct lookup.”h]”(hŒ|On entry, raw_data will be pointing to the criteria to be used in matching
a key by the caller and should not be modified.  ”…””}”(hj÷   h²hh³Nh´Nubjª  )”}”(hŒ``(*cmp)()``”h]”hŒ(*cmp)()”…””}”(hjÿ   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj÷   ubhŒ£ will be pointing
to the default matcher function (which does an exact description match
against raw_data) and lookup_type will be set to indicate a direct lookup.”…””}”(hj÷   h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubhÌ)”}”(hŒ/The following lookup_type values are available:”h]”hŒ/The following lookup_type values are available:”…””}”(hj!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubhø)”}”(hXa  *  KEYRING_SEARCH_LOOKUP_DIRECT - A direct lookup hashes the type and
   description to narrow down the search to a small number of keys.

*  KEYRING_SEARCH_LOOKUP_ITERATE - An iterative lookup walks all the
   keys in the keyring until one is matched.  This must be used for any
   search that's not doing a simple direct match on the key description.
”h]”j%  )”}”(hhh]”(j*  )”}”(hŒ„KEYRING_SEARCH_LOOKUP_DIRECT - A direct lookup hashes the type and
description to narrow down the search to a small number of keys.
”h]”hÌ)”}”(hŒƒKEYRING_SEARCH_LOOKUP_DIRECT - A direct lookup hashes the type and
description to narrow down the search to a small number of keys.”h]”hŒƒKEYRING_SEARCH_LOOKUP_DIRECT - A direct lookup hashes the type and
description to narrow down the search to a small number of keys.”…””}”(hj0!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M
hj,!  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj)!  ubj*  )”}”(hŒÍKEYRING_SEARCH_LOOKUP_ITERATE - An iterative lookup walks all the
keys in the keyring until one is matched.  This must be used for any
search that's not doing a simple direct match on the key description.
”h]”hÌ)”}”(hŒÌKEYRING_SEARCH_LOOKUP_ITERATE - An iterative lookup walks all the
keys in the keyring until one is matched.  This must be used for any
search that's not doing a simple direct match on the key description.”h]”hŒÎKEYRING_SEARCH_LOOKUP_ITERATE - An iterative lookup walks all the
keys in the keyring until one is matched.  This must be used for any
search thatâ€™s not doing a simple direct match on the key description.”…””}”(hjH!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjD!  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j)  hj)!  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´M
hj%!  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M
hjÀ   ubhÌ)”}”(hX%  The method may set cmp to point to a function of its choice that does some
other form of match, may set lookup_type to KEYRING_SEARCH_LOOKUP_ITERATE
and may attach something to the preparsed pointer for use by ``(*cmp)()``.
``(*cmp)()`` should return true if a key matches and false otherwise.”h]”(hŒÒThe method may set cmp to point to a function of its choice that does some
other form of match, may set lookup_type to KEYRING_SEARCH_LOOKUP_ITERATE
and may attach something to the preparsed pointer for use by ”…””}”(hjh!  h²hh³Nh´Nubjª  )”}”(hŒ``(*cmp)()``”h]”hŒ(*cmp)()”…””}”(hjp!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjh!  ubhŒ.
”…””}”(hjh!  h²hh³Nh´Nubjª  )”}”(hŒ``(*cmp)()``”h]”hŒ(*cmp)()”…””}”(hj‚!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjh!  ubhŒ9 should return true if a key matches and false otherwise.”…””}”(hjh!  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubhÌ)”}”(hŒWIf preparsed is set, it may be necessary to use the match_free() method to
clean it up.”h]”hŒWIf preparsed is set, it may be necessary to use the match_free() method to
clean it up.”…””}”(hjš!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubhÌ)”}”(hŒLThe method should return 0 if successful or a negative error code
otherwise.”h]”hŒLThe method should return 0 if successful or a negative error code
otherwise.”…””}”(hj¨!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubhÌ)”}”(hŒfIt is permitted to sleep in this method, but ``(*cmp)()`` may not sleep as
locks will be held over it.”h]”(hŒ-It is permitted to sleep in this method, but ”…””}”(hj¶!  h²hh³Nh´Nubjª  )”}”(hŒ``(*cmp)()``”h]”hŒ(*cmp)()”…””}”(hj¾!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj¶!  ubhŒ- may not sleep as
locks will be held over it.”…””}”(hj¶!  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubhÌ)”}”(hŒdIf match_preparse() is not provided, keys of this type will be matched
exactly by their description.”h]”hŒdIf match_preparse() is not provided, keys of this type will be matched
exactly by their description.”…””}”(hjÖ!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÀ   ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hŒº``void (*match_free)(struct key_match_data *match_data);``

This method is optional.  If given, it called to clean up
match_data->preparsed after a successful call to match_preparse().

”h]”(hÌ)”}”(hŒ:``void (*match_free)(struct key_match_data *match_data);``”h]”jª  )”}”(hjð!  h]”hŒ6void (*match_free)(struct key_match_data *match_data);”…””}”(hjò!  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjî!  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M#hjê!  ubhÌ)”}”(hŒ|This method is optional.  If given, it called to clean up
match_data->preparsed after a successful call to match_preparse().”h]”hŒ|This method is optional.  If given, it called to clean up
match_data->preparsed after a successful call to match_preparse().”…””}”(hj"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M%hjê!  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX2  ``void (*revoke)(struct key *key);``

This method is optional.  It is called to discard part of the payload
data upon a key being revoked.  The caller will have the key semaphore
write-locked.

It is safe to sleep in this method, though care should be taken to avoid
a deadlock against the key semaphore.

”h]”(hÌ)”}”(hŒ$``void (*revoke)(struct key *key);``”h]”jª  )”}”(hj"  h]”hŒ void (*revoke)(struct key *key);”…””}”(hj!"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj"  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M)hj"  ubhÌ)”}”(hŒšThis method is optional.  It is called to discard part of the payload
data upon a key being revoked.  The caller will have the key semaphore
write-locked.”h]”hŒšThis method is optional.  It is called to discard part of the payload
data upon a key being revoked.  The caller will have the key semaphore
write-locked.”…””}”(hj4"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M+hj"  ubhÌ)”}”(hŒnIt is safe to sleep in this method, though care should be taken to avoid
a deadlock against the key semaphore.”h]”hŒnIt is safe to sleep in this method, though care should be taken to avoid
a deadlock against the key semaphore.”…””}”(hjB"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M/hj"  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX¤  ``void (*destroy)(struct key *key);``

This method is optional. It is called to discard the payload data on a key
when it is being destroyed.

This method does not need to lock the key to access the payload; it can
consider the key as being inaccessible at this time. Note that the key's
type may have been changed before this function is called.

It is not safe to sleep in this method; the caller may hold spinlocks.

”h]”(hÌ)”}”(hŒ%``void (*destroy)(struct key *key);``”h]”jª  )”}”(hj\"  h]”hŒ!void (*destroy)(struct key *key);”…””}”(hj^"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjZ"  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M3hjV"  ubhÌ)”}”(hŒfThis method is optional. It is called to discard the payload data on a key
when it is being destroyed.”h]”hŒfThis method is optional. It is called to discard the payload data on a key
when it is being destroyed.”…””}”(hjq"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M5hjV"  ubhÌ)”}”(hŒËThis method does not need to lock the key to access the payload; it can
consider the key as being inaccessible at this time. Note that the key's
type may have been changed before this function is called.”h]”hŒÍThis method does not need to lock the key to access the payload; it can
consider the key as being inaccessible at this time. Note that the keyâ€™s
type may have been changed before this function is called.”…””}”(hj"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M8hjV"  ubhÌ)”}”(hŒFIt is not safe to sleep in this method; the caller may hold spinlocks.”h]”hŒFIt is not safe to sleep in this method; the caller may hold spinlocks.”…””}”(hj"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M<hjV"  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX:  ``void (*describe)(const struct key *key, struct seq_file *p);``

This method is optional. It is called during /proc/keys reading to
summarise a key's description and payload in text form.

This method will be called with the RCU read lock held. rcu_dereference()
should be used to read the payload pointer if the payload is to be
accessed. key->datalen cannot be trusted to stay consistent with the
contents of the payload.

The description will not change, though the key's state may.

It is not safe to sleep in this method; the RCU read lock is held by the
caller.

”h]”(hÌ)”}”(hŒ@``void (*describe)(const struct key *key, struct seq_file *p);``”h]”jª  )”}”(hj§"  h]”hŒ<void (*describe)(const struct key *key, struct seq_file *p);”…””}”(hj©"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj¥"  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M?hj¡"  ubhÌ)”}”(hŒzThis method is optional. It is called during /proc/keys reading to
summarise a key's description and payload in text form.”h]”hŒ|This method is optional. It is called during /proc/keys reading to
summarise a keyâ€™s description and payload in text form.”…””}”(hj¼"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MAhj¡"  ubhÌ)”}”(hŒêThis method will be called with the RCU read lock held. rcu_dereference()
should be used to read the payload pointer if the payload is to be
accessed. key->datalen cannot be trusted to stay consistent with the
contents of the payload.”h]”hŒêThis method will be called with the RCU read lock held. rcu_dereference()
should be used to read the payload pointer if the payload is to be
accessed. key->datalen cannot be trusted to stay consistent with the
contents of the payload.”…””}”(hjÊ"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MDhj¡"  ubhÌ)”}”(hŒ<The description will not change, though the key's state may.”h]”hŒ>The description will not change, though the keyâ€™s state may.”…””}”(hjØ"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MIhj¡"  ubhÌ)”}”(hŒPIt is not safe to sleep in this method; the RCU read lock is held by the
caller.”h]”hŒPIt is not safe to sleep in this method; the RCU read lock is held by the
caller.”…””}”(hjæ"  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MKhj¡"  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hXÃ  ``long (*read)(const struct key *key, char __user *buffer, size_t buflen);``

This method is optional. It is called by KEYCTL_READ to translate the
key's payload into something a blob of data for userspace to deal with.
Ideally, the blob should be in the same format as that passed in to the
instantiate and update methods.

If successful, the blob size that could be produced should be returned
rather than the size copied.

This method will be called with the key's semaphore read-locked. This will
prevent the key's payload changing. It is not necessary to use RCU locking
when accessing the key's payload. It is safe to sleep in this method, such
as might happen when the userspace buffer is accessed.

”h]”(hÌ)”}”(hŒL``long (*read)(const struct key *key, char __user *buffer, size_t buflen);``”h]”jª  )”}”(hj #  h]”hŒHlong (*read)(const struct key *key, char __user *buffer, size_t buflen);”…””}”(hj#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjþ"  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MOhjú"  ubhÌ)”}”(hŒõThis method is optional. It is called by KEYCTL_READ to translate the
key's payload into something a blob of data for userspace to deal with.
Ideally, the blob should be in the same format as that passed in to the
instantiate and update methods.”h]”hŒ÷This method is optional. It is called by KEYCTL_READ to translate the
keyâ€™s payload into something a blob of data for userspace to deal with.
Ideally, the blob should be in the same format as that passed in to the
instantiate and update methods.”…””}”(hj#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MQhjú"  ubhÌ)”}”(hŒcIf successful, the blob size that could be produced should be returned
rather than the size copied.”h]”hŒcIf successful, the blob size that could be produced should be returned
rather than the size copied.”…””}”(hj##  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MVhjú"  ubhÌ)”}”(hX  This method will be called with the key's semaphore read-locked. This will
prevent the key's payload changing. It is not necessary to use RCU locking
when accessing the key's payload. It is safe to sleep in this method, such
as might happen when the userspace buffer is accessed.”h]”hX  This method will be called with the keyâ€™s semaphore read-locked. This will
prevent the keyâ€™s payload changing. It is not necessary to use RCU locking
when accessing the keyâ€™s payload. It is safe to sleep in this method, such
as might happen when the userspace buffer is accessed.”…””}”(hj1#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MYhjú"  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX«  ``int (*request_key)(struct key_construction *cons, const char *op, void *aux);``

This method is optional.  If provided, request_key() and friends will
invoke this function rather than upcalling to /sbin/request-key to operate
upon a key of this type.

The aux parameter is as passed to request_key_async_with_auxdata() and
similar or is NULL otherwise.  Also passed are the construction record for
the key to be operated upon and the operation type (currently only
"create").

This method is permitted to return before the upcall is complete, but the
following function must be called under all circumstances to complete the
instantiation process, whether or not it succeeds, whether or not there's
an error::

   void complete_request_key(struct key_construction *cons, int error);

The error parameter should be 0 on success, -ve on error.  The
construction record is destroyed by this action and the authorisation key
will be revoked.  If an error is indicated, the key under construction
will be negatively instantiated if it wasn't already instantiated.

If this method returns an error, that error will be returned to the
caller of request_key*().  complete_request_key() must be called prior to
returning.

The key under construction and the authorisation key can be found in the
key_construction struct pointed to by cons:

 *  ``struct key *key;``

    The key under construction.

 *  ``struct key *authkey;``

    The authorisation key.

”h]”(hÌ)”}”(hŒQ``int (*request_key)(struct key_construction *cons, const char *op, void *aux);``”h]”jª  )”}”(hjK#  h]”hŒMint (*request_key)(struct key_construction *cons, const char *op, void *aux);”…””}”(hjM#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjI#  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M_hjE#  ubhÌ)”}”(hŒ©This method is optional.  If provided, request_key() and friends will
invoke this function rather than upcalling to /sbin/request-key to operate
upon a key of this type.”h]”hŒ©This method is optional.  If provided, request_key() and friends will
invoke this function rather than upcalling to /sbin/request-key to operate
upon a key of this type.”…””}”(hj`#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MahjE#  ubhÌ)”}”(hŒßThe aux parameter is as passed to request_key_async_with_auxdata() and
similar or is NULL otherwise.  Also passed are the construction record for
the key to be operated upon and the operation type (currently only
"create").”h]”hŒãThe aux parameter is as passed to request_key_async_with_auxdata() and
similar or is NULL otherwise.  Also passed are the construction record for
the key to be operated upon and the operation type (currently only
â€œcreateâ€).”…””}”(hjn#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MehjE#  ubhÌ)”}”(hŒèThis method is permitted to return before the upcall is complete, but the
following function must be called under all circumstances to complete the
instantiation process, whether or not it succeeds, whether or not there's
an error::”h]”hŒéThis method is permitted to return before the upcall is complete, but the
following function must be called under all circumstances to complete the
instantiation process, whether or not it succeeds, whether or not thereâ€™s
an error:”…””}”(hj|#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MjhjE#  ubjC	  )”}”(hŒDvoid complete_request_key(struct key_construction *cons, int error);”h]”hŒDvoid complete_request_key(struct key_construction *cons, int error);”…””}”hjŠ#  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MohjE#  ubhÌ)”}”(hX  The error parameter should be 0 on success, -ve on error.  The
construction record is destroyed by this action and the authorisation key
will be revoked.  If an error is indicated, the key under construction
will be negatively instantiated if it wasn't already instantiated.”h]”hX  The error parameter should be 0 on success, -ve on error.  The
construction record is destroyed by this action and the authorisation key
will be revoked.  If an error is indicated, the key under construction
will be negatively instantiated if it wasnâ€™t already instantiated.”…””}”(hj˜#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MqhjE#  ubhÌ)”}”(hŒ˜If this method returns an error, that error will be returned to the
caller of request_key*().  complete_request_key() must be called prior to
returning.”h]”hŒ˜If this method returns an error, that error will be returned to the
caller of request_key*().  complete_request_key() must be called prior to
returning.”…””}”(hj¦#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MvhjE#  ubhÌ)”}”(hŒtThe key under construction and the authorisation key can be found in the
key_construction struct pointed to by cons:”h]”hŒtThe key under construction and the authorisation key can be found in the
key_construction struct pointed to by cons:”…””}”(hj´#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MzhjE#  ubhø)”}”(hŒq*  ``struct key *key;``

   The key under construction.

*  ``struct key *authkey;``

   The authorisation key.

”h]”j%  )”}”(hhh]”(j*  )”}”(hŒ2``struct key *key;``

The key under construction.
”h]”(hÌ)”}”(hŒ``struct key *key;``”h]”jª  )”}”(hjÏ#  h]”hŒstruct key *key;”…””}”(hjÑ#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjÍ#  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M}hjÉ#  ubhÌ)”}”(hŒThe key under construction.”h]”hŒThe key under construction.”…””}”(hjä#  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjÉ#  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjÆ#  ubj*  )”}”(hŒ2``struct key *authkey;``

The authorisation key.

”h]”(hÌ)”}”(hŒ``struct key *authkey;``”h]”jª  )”}”(hjþ#  h]”hŒstruct key *authkey;”…””}”(hj $  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjü#  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjø#  ubhÌ)”}”(hŒThe authorisation key.”h]”hŒThe authorisation key.”…””}”(hj$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mƒhjø#  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjÆ#  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´M}hjÂ#  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M}hjE#  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX¸  ``struct key_restriction *(*lookup_restriction)(const char *params);``

This optional method is used to enable userspace configuration of keyring
restrictions. The restriction parameter string (not including the key type
name) is passed in, and this method returns a pointer to a key_restriction
structure containing the relevant functions and data to evaluate each
attempted key link operation. If there is no match, -EINVAL is returned.

”h]”(hÌ)”}”(hŒF``struct key_restriction *(*lookup_restriction)(const char *params);``”h]”jª  )”}”(hj?$  h]”hŒBstruct key_restriction *(*lookup_restriction)(const char *params);”…””}”(hjA$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hj=$  ubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M†hj9$  ubhÌ)”}”(hXn  This optional method is used to enable userspace configuration of keyring
restrictions. The restriction parameter string (not including the key type
name) is passed in, and this method returns a pointer to a key_restriction
structure containing the relevant functions and data to evaluate each
attempted key link operation. If there is no match, -EINVAL is returned.”h]”hXn  This optional method is used to enable userspace configuration of keyring
restrictions. The restriction parameter string (not including the key type
name) is passed in, and this method returns a pointer to a key_restriction
structure containing the relevant functions and data to evaluate each
attempted key link operation. If there is no match, -EINVAL is returned.”…””}”(hjT$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mˆhj9$  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hX   ``asym_eds_op`` and ``asym_verify_signature``::

  int (*asym_eds_op)(struct kernel_pkey_params *params,
                     const void *in, void *out);
  int (*asym_verify_signature)(struct kernel_pkey_params *params,
                               const void *in, const void *in2);

These methods are optional.  If provided the first allows a key to be
used to encrypt, decrypt or sign a blob of data, and the second allows a
key to verify a signature.

In all cases, the following information is provided in the params block::

   struct kernel_pkey_params {
           struct key      *key;
           const char      *encoding;
           const char      *hash_algo;
           char            *info;
           __u32           in_len;
           union {
                   __u32   out_len;
                   __u32   in2_len;
           };
           enum kernel_pkey_operation op : 8;
   };

This includes the key to be used; a string indicating the encoding to use
(for instance, "pkcs1" may be used with an RSA key to indicate
RSASSA-PKCS1-v1.5 or RSAES-PKCS1-v1.5 encoding or "raw" if no encoding);
the name of the hash algorithm used to generate the data for a signature
(if appropriate); the sizes of the input and output (or second input)
buffers; and the ID of the operation to be performed.

For a given operation ID, the input and output buffers are used as
follows::

   Operation ID            in,in_len       out,out_len     in2,in2_len
   ======================= =============== =============== ===============
   kernel_pkey_encrypt     Raw data        Encrypted data  -
   kernel_pkey_decrypt     Encrypted data  Raw data        -
   kernel_pkey_sign        Raw data        Signature       -
   kernel_pkey_verify      Raw data        -               Signature

asym_eds_op() deals with encryption, decryption and signature creation as
specified by params->op.  Note that params->op is also set for
asym_verify_signature().

Encrypting and signature creation both take raw data in the input buffer
and return the encrypted result in the output buffer.  Padding may have
been added if an encoding was set.  In the case of signature creation,
depending on the encoding, the padding created may need to indicate the
digest algorithm - the name of which should be supplied in hash_algo.

Decryption takes encrypted data in the input buffer and returns the raw
data in the output buffer.  Padding will get checked and stripped off if
an encoding was set.

Verification takes raw data in the input buffer and the signature in the
second input buffer and checks that the one matches the other.  Padding
will be validated.  Depending on the encoding, the digest algorithm used
to generate the raw data may need to be indicated in hash_algo.

If successful, asym_eds_op() should return the number of bytes written
into the output buffer.  asym_verify_signature() should return 0.

A variety of errors may be returned, including EOPNOTSUPP if the operation
is not supported; EKEYREJECTED if verification fails; ENOPKG if the
required crypto isn't available.

”h]”(hÌ)”}”(hŒ/``asym_eds_op`` and ``asym_verify_signature``::”h]”(jª  )”}”(hŒ``asym_eds_op``”h]”hŒasym_eds_op”…””}”(hjp$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjl$  ubhŒ and ”…””}”(hjl$  h²hh³Nh´Nubjª  )”}”(hŒ``asym_verify_signature``”h]”hŒasym_verify_signature”…””}”(hj‚$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjl$  ubhŒ:”…””}”(hjl$  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhjh$  ubjC	  )”}”(hŒãint (*asym_eds_op)(struct kernel_pkey_params *params,
                   const void *in, void *out);
int (*asym_verify_signature)(struct kernel_pkey_params *params,
                             const void *in, const void *in2);”h]”hŒãint (*asym_eds_op)(struct kernel_pkey_params *params,
                   const void *in, void *out);
int (*asym_verify_signature)(struct kernel_pkey_params *params,
                             const void *in, const void *in2);”…””}”hjš$  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M‘hjh$  ubhÌ)”}”(hŒ©These methods are optional.  If provided the first allows a key to be
used to encrypt, decrypt or sign a blob of data, and the second allows a
key to verify a signature.”h]”hŒ©These methods are optional.  If provided the first allows a key to be
used to encrypt, decrypt or sign a blob of data, and the second allows a
key to verify a signature.”…””}”(hj¨$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M–hjh$  ubhÌ)”}”(hŒIIn all cases, the following information is provided in the params block::”h]”hŒHIn all cases, the following information is provided in the params block:”…””}”(hj¶$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mšhjh$  ubjC	  )”}”(hXJ  struct kernel_pkey_params {
        struct key      *key;
        const char      *encoding;
        const char      *hash_algo;
        char            *info;
        __u32           in_len;
        union {
                __u32   out_len;
                __u32   in2_len;
        };
        enum kernel_pkey_operation op : 8;
};”h]”hXJ  struct kernel_pkey_params {
        struct key      *key;
        const char      *encoding;
        const char      *hash_algo;
        char            *info;
        __u32           in_len;
        union {
                __u32   out_len;
                __u32   in2_len;
        };
        enum kernel_pkey_operation op : 8;
};”…””}”hjÄ$  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mœhjh$  ubhÌ)”}”(hX–  This includes the key to be used; a string indicating the encoding to use
(for instance, "pkcs1" may be used with an RSA key to indicate
RSASSA-PKCS1-v1.5 or RSAES-PKCS1-v1.5 encoding or "raw" if no encoding);
the name of the hash algorithm used to generate the data for a signature
(if appropriate); the sizes of the input and output (or second input)
buffers; and the ID of the operation to be performed.”h]”hXž  This includes the key to be used; a string indicating the encoding to use
(for instance, â€œpkcs1â€ may be used with an RSA key to indicate
RSASSA-PKCS1-v1.5 or RSAES-PKCS1-v1.5 encoding or â€œrawâ€ if no encoding);
the name of the hash algorithm used to generate the data for a signature
(if appropriate); the sizes of the input and output (or second input)
buffers; and the ID of the operation to be performed.”…””}”(hjÒ$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M©hjh$  ubhÌ)”}”(hŒLFor a given operation ID, the input and output buffers are used as
follows::”h]”hŒKFor a given operation ID, the input and output buffers are used as
follows:”…””}”(hjà$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M°hjh$  ubjC	  )”}”(hX{  Operation ID            in,in_len       out,out_len     in2,in2_len
======================= =============== =============== ===============
kernel_pkey_encrypt     Raw data        Encrypted data  -
kernel_pkey_decrypt     Encrypted data  Raw data        -
kernel_pkey_sign        Raw data        Signature       -
kernel_pkey_verify      Raw data        -               Signature”h]”hX{  Operation ID            in,in_len       out,out_len     in2,in2_len
======================= =============== =============== ===============
kernel_pkey_encrypt     Raw data        Encrypted data  -
kernel_pkey_decrypt     Encrypted data  Raw data        -
kernel_pkey_sign        Raw data        Signature       -
kernel_pkey_verify      Raw data        -               Signature”…””}”hjî$  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M³hjh$  ubhÌ)”}”(hŒ¡asym_eds_op() deals with encryption, decryption and signature creation as
specified by params->op.  Note that params->op is also set for
asym_verify_signature().”h]”hŒ¡asym_eds_op() deals with encryption, decryption and signature creation as
specified by params->op.  Note that params->op is also set for
asym_verify_signature().”…””}”(hjü$  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mºhjh$  ubhÌ)”}”(hXe  Encrypting and signature creation both take raw data in the input buffer
and return the encrypted result in the output buffer.  Padding may have
been added if an encoding was set.  In the case of signature creation,
depending on the encoding, the padding created may need to indicate the
digest algorithm - the name of which should be supplied in hash_algo.”h]”hXe  Encrypting and signature creation both take raw data in the input buffer
and return the encrypted result in the output buffer.  Padding may have
been added if an encoding was set.  In the case of signature creation,
depending on the encoding, the padding created may need to indicate the
digest algorithm - the name of which should be supplied in hash_algo.”…””}”(hj
%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M¾hjh$  ubhÌ)”}”(hŒ¥Decryption takes encrypted data in the input buffer and returns the raw
data in the output buffer.  Padding will get checked and stripped off if
an encoding was set.”h]”hŒ¥Decryption takes encrypted data in the input buffer and returns the raw
data in the output buffer.  Padding will get checked and stripped off if
an encoding was set.”…””}”(hj%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÄhjh$  ubhÌ)”}”(hX  Verification takes raw data in the input buffer and the signature in the
second input buffer and checks that the one matches the other.  Padding
will be validated.  Depending on the encoding, the digest algorithm used
to generate the raw data may need to be indicated in hash_algo.”h]”hX  Verification takes raw data in the input buffer and the signature in the
second input buffer and checks that the one matches the other.  Padding
will be validated.  Depending on the encoding, the digest algorithm used
to generate the raw data may need to be indicated in hash_algo.”…””}”(hj&%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÈhjh$  ubhÌ)”}”(hŒˆIf successful, asym_eds_op() should return the number of bytes written
into the output buffer.  asym_verify_signature() should return 0.”h]”hŒˆIf successful, asym_eds_op() should return the number of bytes written
into the output buffer.  asym_verify_signature() should return 0.”…””}”(hj4%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÍhjh$  ubhÌ)”}”(hŒ¯A variety of errors may be returned, including EOPNOTSUPP if the operation
is not supported; EKEYREJECTED if verification fails; ENOPKG if the
required crypto isn't available.”h]”hŒ±A variety of errors may be returned, including EOPNOTSUPP if the operation
is not supported; EKEYREJECTED if verification fails; ENOPKG if the
required crypto isnâ€™t available.”…””}”(hjB%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÐhjh$  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubj*  )”}”(hXù  ``asym_query``::

  int (*asym_query)(const struct kernel_pkey_params *params,
                    struct kernel_pkey_query *info);

This method is optional.  If provided it allows information about the
public or asymmetric key held in the key to be determined.

The parameter block is as for asym_eds_op() and co. but in_len and out_len
are unused.  The encoding and hash_algo fields should be used to reduce
the returned buffer/data sizes as appropriate.

If successful, the following information is filled in::

   struct kernel_pkey_query {
           __u32           supported_ops;
           __u32           key_size;
           __u16           max_data_size;
           __u16           max_sig_size;
           __u16           max_enc_size;
           __u16           max_dec_size;
   };

The supported_ops field will contain a bitmask indicating what operations
are supported by the key, including encryption of a blob, decryption of a
blob, signing a blob and verifying the signature on a blob.  The following
constants are defined for this::

   KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}

The key_size field is the size of the key in bits.  max_data_size and
max_sig_size are the maximum raw data and signature sizes for creation and
verification of a signature; max_enc_size and max_dec_size are the maximum
raw data and signature sizes for encryption and decryption.  The
max_*_size fields are measured in bytes.

If successful, 0 will be returned.  If the key doesn't support this,
EOPNOTSUPP will be returned.

”h]”(hÌ)”}”(hŒ``asym_query``::”h]”(jª  )”}”(hŒ``asym_query``”h]”hŒ
asym_query”…””}”(hj^%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j©  hjZ%  ubhŒ:”…””}”(hjZ%  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÕhjV%  ubjC	  )”}”(hŒmint (*asym_query)(const struct kernel_pkey_params *params,
                  struct kernel_pkey_query *info);”h]”hŒmint (*asym_query)(const struct kernel_pkey_params *params,
                  struct kernel_pkey_query *info);”…””}”hjv%  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M×hjV%  ubhÌ)”}”(hŒ€This method is optional.  If provided it allows information about the
public or asymmetric key held in the key to be determined.”h]”hŒ€This method is optional.  If provided it allows information about the
public or asymmetric key held in the key to be determined.”…””}”(hj„%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÚhjV%  ubhÌ)”}”(hŒÁThe parameter block is as for asym_eds_op() and co. but in_len and out_len
are unused.  The encoding and hash_algo fields should be used to reduce
the returned buffer/data sizes as appropriate.”h]”hŒÁThe parameter block is as for asym_eds_op() and co. but in_len and out_len
are unused.  The encoding and hash_algo fields should be used to reduce
the returned buffer/data sizes as appropriate.”…””}”(hj’%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MÝhjV%  ubhÌ)”}”(hŒ7If successful, the following information is filled in::”h]”hŒ6If successful, the following information is filled in:”…””}”(hj %  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MáhjV%  ubjC	  )”}”(hŒÿstruct kernel_pkey_query {
        __u32           supported_ops;
        __u32           key_size;
        __u16           max_data_size;
        __u16           max_sig_size;
        __u16           max_enc_size;
        __u16           max_dec_size;
};”h]”hŒÿstruct kernel_pkey_query {
        __u32           supported_ops;
        __u32           key_size;
        __u16           max_data_size;
        __u16           max_sig_size;
        __u16           max_enc_size;
        __u16           max_dec_size;
};”…””}”hj®%  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MãhjV%  ubhÌ)”}”(hŒÿThe supported_ops field will contain a bitmask indicating what operations
are supported by the key, including encryption of a blob, decryption of a
blob, signing a blob and verifying the signature on a blob.  The following
constants are defined for this::”h]”hŒþThe supported_ops field will contain a bitmask indicating what operations
are supported by the key, including encryption of a blob, decryption of a
blob, signing a blob and verifying the signature on a blob.  The following
constants are defined for this:”…””}”(hj¼%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MìhjV%  ubjC	  )”}”(hŒ-KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}”h]”hŒ-KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}”…””}”hjÊ%  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´MñhjV%  ubhÌ)”}”(hXE  The key_size field is the size of the key in bits.  max_data_size and
max_sig_size are the maximum raw data and signature sizes for creation and
verification of a signature; max_enc_size and max_dec_size are the maximum
raw data and signature sizes for encryption and decryption.  The
max_*_size fields are measured in bytes.”h]”hXE  The key_size field is the size of the key in bits.  max_data_size and
max_sig_size are the maximum raw data and signature sizes for creation and
verification of a signature; max_enc_size and max_dec_size are the maximum
raw data and signature sizes for encryption and decryption.  The
max_*_size fields are measured in bytes.”…””}”(hjØ%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MóhjV%  ubhÌ)”}”(hŒaIf successful, 0 will be returned.  If the key doesn't support this,
EOPNOTSUPP will be returned.”h]”hŒcIf successful, 0 will be returned.  If the key doesnâ€™t support this,
EOPNOTSUPP will be returned.”…””}”(hjæ%  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MùhjV%  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j)  hjx  ubeh}”(h]”h ]”h"]”h$]”h&]”j”  j2  uh1j$  h³hÊh´M€hjt  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M€hj+  h²hubeh}”(h]”jR  ah ]”h"]”Œdefining a key type”ah$]”h&]”uh1hµhh·h²hh³hÊh´Mtubh¶)”}”(hhh]”(h»)”}”(hŒRequest-Key Callback Service”h]”hŒRequest-Key Callback Service”…””}”(hj&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  jn  uh1hºhj&  h²hh³hÊh´MþubhÌ)”}”(hŒTTo create a new key, the kernel will attempt to execute the following command
line::”h]”hŒSTo create a new key, the kernel will attempt to execute the following command
line:”…””}”(hj&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M hj&  h²hubjC	  )”}”(hŒl/sbin/request-key create <key> <uid> <gid> \
        <threadring> <processring> <sessionring> <callout_info>”h]”hŒl/sbin/request-key create <key> <uid> <gid> \
        <threadring> <processring> <sessionring> <callout_info>”…””}”hj,&  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´Mhj&  h²hubhÌ)”}”(hŒ­<key> is the key being constructed, and the three keyrings are the process
keyrings from the process that caused the search to be issued. These are
included for two reasons:”h]”hŒ­<key> is the key being constructed, and the three keyrings are the process
keyrings from the process that caused the search to be issued. These are
included for two reasons:”…””}”(hj:&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj&  h²hubhø)”}”(hŒÎ1  There may be an authentication token in one of the keyrings that is
   required to obtain the key, eg: a Kerberos Ticket-Granting Ticket.

2  The new key should probably be cached in one of these rings.
”h]”(jf  )”}”(hhh]”jk  )”}”(hŒŠ1  There may be an authentication token in one of the keyrings that is
required to obtain the key, eg: a Kerberos Ticket-Granting Ticket.
”h]”(jq  )”}”(hŒF1  There may be an authentication token in one of the keyrings that is”h]”hŒF1  There may be an authentication token in one of the keyrings that is”…””}”(hjS&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jp  h³hÊh´MhjO&  ubj  )”}”(hhh]”hÌ)”}”(hŒBrequired to obtain the key, eg: a Kerberos Ticket-Granting Ticket.”h]”hŒBrequired to obtain the key, eg: a Kerberos Ticket-Granting Ticket.”…””}”(hjd&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhja&  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jŽ  hjO&  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jj  h³hÊh´MhjL&  ubah}”(h]”h ]”h"]”h$]”h&]”uh1je  hjH&  ubhÌ)”}”(hŒ?2  The new key should probably be cached in one of these rings.”h]”hŒ?2  The new key should probably be cached in one of these rings.”…””}”(hj„&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´MhjH&  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1h÷h³hÊh´M
hj&  h²hubhÌ)”}”(hX  This program should set it UID and GID to those specified before attempting to
access any more keys. It may then look around for a user specific process to
hand the request off to (perhaps a path held in placed in another key by, for
example, the KDE desktop manager).”h]”hX  This program should set it UID and GID to those specified before attempting to
access any more keys. It may then look around for a user specific process to
hand the request off to (perhaps a path held in placed in another key by, for
example, the KDE desktop manager).”…””}”(hj˜&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj&  h²hubhÌ)”}”(hXƒ  The program (or whatever it calls) should finish construction of the key by
calling KEYCTL_INSTANTIATE or KEYCTL_INSTANTIATE_IOV, which also permits it to
cache the key in one of the keyrings (probably the session ring) before
returning.  Alternatively, the key can be marked as negative with KEYCTL_NEGATE
or KEYCTL_REJECT; this also permits the key to be cached in one of the
keyrings.”h]”hXƒ  The program (or whatever it calls) should finish construction of the key by
calling KEYCTL_INSTANTIATE or KEYCTL_INSTANTIATE_IOV, which also permits it to
cache the key in one of the keyrings (probably the session ring) before
returning.  Alternatively, the key can be marked as negative with KEYCTL_NEGATE
or KEYCTL_REJECT; this also permits the key to be cached in one of the
keyrings.”…””}”(hj¦&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj&  h²hubhÌ)”}”(hŒÇIf it returns with the key remaining in the unconstructed state, the key will
be marked as being negative, it will be added to the session keyring, and an
error will be returned to the key requestor.”h]”hŒÇIf it returns with the key remaining in the unconstructed state, the key will
be marked as being negative, it will be added to the session keyring, and an
error will be returned to the key requestor.”…””}”(hj´&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj&  h²hubhÌ)”}”(hŒëSupplementary information may be provided from whoever or whatever invoked this
service. This will be passed as the <callout_info> parameter. If no such
information was made available, then "-" will be passed as this parameter
instead.”h]”hŒïSupplementary information may be provided from whoever or whatever invoked this
service. This will be passed as the <callout_info> parameter. If no such
information was made available, then â€œ-â€ will be passed as this parameter
instead.”…””}”(hjÂ&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´Mhj&  h²hubhÌ)”}”(hŒ]Similarly, the kernel may attempt to update an expired or a soon to expire key
by executing::”h]”hŒ\Similarly, the kernel may attempt to update an expired or a soon to expire key
by executing:”…””}”(hjÐ&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M%hj&  h²hubjC	  )”}”(hŒ]/sbin/request-key update <key> <uid> <gid> \
        <threadring> <processring> <sessionring>”h]”hŒ]/sbin/request-key update <key> <uid> <gid> \
        <threadring> <processring> <sessionring>”…””}”hjÞ&  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M(hj&  h²hubhÌ)”}”(hŒtIn this case, the program isn't required to actually attach the key to a ring;
the rings are provided for reference.”h]”hŒvIn this case, the program isnâ€™t required to actually attach the key to a ring;
the rings are provided for reference.”…””}”(hjì&  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M+hj&  h²hubeh}”(h]”jt  ah ]”h"]”Œrequest-key callback service”ah$]”h&]”uh1hµhh·h²hh³hÊh´Mþubh¶)”}”(hhh]”(h»)”}”(hŒGarbage Collection”h]”hŒGarbage Collection”…””}”(hj'  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”jÄ  j  uh1hºhj'  h²hh³hÊh´M0ubhÌ)”}”(hŒ¸Dead keys (for which the type has been removed) will be automatically unlinked
from those keyrings that point to them and deleted as soon as possible by a
background garbage collector.”•}      h]”hŒ¸Dead keys (for which the type has been removed) will be automatically unlinked
from those keyrings that point to them and deleted as soon as possible by a
background garbage collector.”…””}”(hj'  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M2hj'  h²hubhÌ)”}”(hŒ Similarly, revoked and expired keys will be garbage collected, but only after a
certain amount of time has passed.  This time is set as a number of seconds in::”h]”hŒŸSimilarly, revoked and expired keys will be garbage collected, but only after a
certain amount of time has passed.  This time is set as a number of seconds in:”…””}”(hj '  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hËh³hÊh´M6hj'  h²hubjC	  )”}”(hŒ/proc/sys/kernel/keys/gc_delay”h]”hŒ/proc/sys/kernel/keys/gc_delay”…””}”hj.'  sbah}”(h]”h ]”h"]”h$]”h&]”jR	  jS	  uh1jB	  h³hÊh´M9hj'  h²hubeh}”(h]”j–  ah ]”h"]”Œgarbage collection”ah$]”h&]”uh1hµhh·h²hh³hÊh´M0ubeh}”(h]”Œkernel-key-retention-service”ah ]”h"]”Œkernel key retention service”ah$]”h&]”uh1hµhhh²hh³hÊh´Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”hÊuh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(hºNŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jn'  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”hÊŒ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(jH'  jE'  j°  j«  j]  jB  jT  jd  j  j†  jÝ  j¨  jQ
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