€•Ý(      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/tpm/tpm_event_log”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$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/zh_TW/security/tpm/tpm_event_log”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/it_IT/security/tpm/tpm_event_log”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ja_JP/security/tpm/tpm_event_log”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ko_KR/security/tpm/tpm_event_log”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/sp_SP/security/tpm/tpm_event_log”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh£sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1h¡hhhžhhŸŒH/var/lib/git/docbuild/linux/Documentation/security/tpm/tpm_event_log.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒTPM Event Log”h]”hŒTPM Event Log”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h KubhŒ	paragraph”“”)”}”(hŒ|This document briefly describes what TPM log is and how it is handed
over from the preboot firmware to the operating system.”h]”hŒ|This document briefly describes what TPM log is and how it is handed
over from the preboot firmware to the operating system.”…””}”(hhËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhµ)”}”(hhh]”(hº)”}”(hŒIntroduction”h]”hŒIntroduction”…””}”(hhÜhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hhÙhžhhŸh³h KubhÊ)”}”(hXg  The preboot firmware maintains an event log that gets new entries every
time something gets hashed by it to any of the PCR registers. The events
are segregated by their type and contain the value of the hashed PCR
register. Typically, the preboot firmware will hash the components to
who execution is to be handed over or actions relevant to the boot
process.”h]”hXg  The preboot firmware maintains an event log that gets new entries every
time something gets hashed by it to any of the PCR registers. The events
are segregated by their type and contain the value of the hashed PCR
register. Typically, the preboot firmware will hash the components to
who execution is to be handed over or actions relevant to the boot
process.”…””}”(hhêhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhhÙhžhubhÊ)”}”(hŒƒThe main application for this is remote attestation and the reason why
it is useful is nicely put in the very first section of [1]:”h]”hŒƒThe main application for this is remote attestation and the reason why
it is useful is nicely put in the very first section of [1]:”…””}”(hhøhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhhÙhžhubhÊ)”}”(hX·  "Attestation is used to provide information about the platformâ€™s state
to a challenger. However, PCR contents are difficult to interpret;
therefore, attestation is typically more useful when the PCR contents
are accompanied by a measurement log. While not trusted on their own,
the measurement log contains a richer set of information than do the PCR
contents. The PCR contents are used to provide the validation of the
measurement log."”h]”hX»  â€œAttestation is used to provide information about the platformâ€™s state
to a challenger. However, PCR contents are difficult to interpret;
therefore, attestation is typically more useful when the PCR contents
are accompanied by a measurement log. While not trusted on their own,
the measurement log contains a richer set of information than do the PCR
contents. The PCR contents are used to provide the validation of the
measurement log.â€”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhhÙhžhubeh}”(h]”Œintroduction”ah ]”h"]”Œintroduction”ah$]”h&]”uh1h´hh¶hžhhŸh³h Kubhµ)”}”(hhh]”(hº)”}”(hŒUEFI event log”h]”hŒUEFI event log”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hj  hžhhŸh³h K ubhÊ)”}”(hŒ8UEFI provided event log has a few somewhat weird quirks.”h]”hŒ8UEFI provided event log has a few somewhat weird quirks.”…””}”(hj-  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K"hj  hžhubhÊ)”}”(hŒÖBefore calling ExitBootServices() Linux EFI stub copies the event log to
a custom configuration table defined by the stub itself. Unfortunately,
the events generated by ExitBootServices() don't end up in the table.”h]”hŒØBefore calling ExitBootServices() Linux EFI stub copies the event log to
a custom configuration table defined by the stub itself. Unfortunately,
the events generated by ExitBootServices() donâ€™t end up in the table.”…””}”(hj;  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K$hj  hžhubhÊ)”}”(hŒ½The firmware provides so called final events configuration table to sort
out this issue. Events gets mirrored to this table after the first time
EFI_TCG2_PROTOCOL.GetEventLog() gets called.”h]”hŒ½The firmware provides so called final events configuration table to sort
out this issue. Events gets mirrored to this table after the first time
EFI_TCG2_PROTOCOL.GetEventLog() gets called.”…””}”(hjI  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K(hj  hžhubhÊ)”}”(hX˜  This introduces another problem: nothing guarantees that it is not called
before the Linux EFI stub gets to run. Thus, it needs to calculate and save the
final events table size while the stub is still running to the custom
configuration table so that the TPM driver can later on skip these events when
concatenating two halves of the event log from the custom configuration table
and the final events table.”h]”hX˜  This introduces another problem: nothing guarantees that it is not called
before the Linux EFI stub gets to run. Thus, it needs to calculate and save the
final events table size while the stub is still running to the custom
configuration table so that the TPM driver can later on skip these events when
concatenating two halves of the event log from the custom configuration table
and the final events table.”…””}”(hjW  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K,hj  hžhubeh}”(h]”Œuefi-event-log”ah ]”h"]”Œuefi event log”ah$]”h&]”uh1h´hh¶hžhhŸh³h K ubhµ)”}”(hhh]”(hº)”}”(hŒ
References”h]”hŒ
References”…””}”(hjp  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hjm  hžhhŸh³h K4ubhŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒj[1] https://trustedcomputinggroup.org/resource/pc-client-specific-platform-firmware-profile-specification/”h]”hÊ)”}”(hj‡  h]”(hŒ[1] ”…””}”(hj‰  hžhhŸNh NubhŒ	reference”“”)”}”(hŒfhttps://trustedcomputinggroup.org/resource/pc-client-specific-platform-firmware-profile-specification/”h]”hŒfhttps://trustedcomputinggroup.org/resource/pc-client-specific-platform-firmware-profile-specification/”…””}”(hj’  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”j”  uh1j  hj‰  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K6hj…  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jƒ  hj€  hžhhŸh³h Nubj„  )”}”(hŒF[2] The final concatenation is done in drivers/char/tpm/eventlog/efi.c”h]”hÊ)”}”(hj¯  h]”hŒF[2] The final concatenation is done in drivers/char/tpm/eventlog/efi.c”…””}”(hj±  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K7hj­  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jƒ  hj€  hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1j~  hŸh³h K6hjm  hžhubeh}”(h]”Œ
references”ah ]”h"]”Œ
references”ah$]”h&]”uh1h´hh¶hžhhŸh³h K4ubeh}”(h]”Œtpm-event-log”ah ]”h"]”Œtpm event log”ah$]”h&]”uh1h´hhhžhhŸh³h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h³uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¹NŒ	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”jÿ  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”h³Œ_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”}”(jÙ  jÖ  j  j  jj  jg  jÑ  jÎ  uŒ	nametypes”}”(jÙ  ‰j  ‰jj  ‰jÑ  ‰uh}”(jÖ  h¶j  hÙjg  j  jÎ  jm  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nhžhub.