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| author | Roberto Sassu <roberto.sassu@huawei.com> | 2023-11-16 10:01:24 +0100 |
|---|---|---|
| committer | Casey Schaufler <casey@schaufler-ca.com> | 2024-01-24 14:06:26 -0800 |
| commit | e63d86b8b76437815fc040e8e65da257c28ba922 (patch) | |
| tree | 394e09b7213aa0fc16e3f0f63619bea0cfb6408f /security | |
| parent | 51b15e7990cb5ac42c3aba82f46e1d95e0dd2310 (diff) | |
| download | linux-e63d86b8b76437815fc040e8e65da257c28ba922.tar.gz | |
smack: Initialize the in-memory inode in smack_inode_init_security()
Currently, Smack initializes in-memory new inodes in three steps. It first
sets the xattrs in smack_inode_init_security(), fetches them in
smack_d_instantiate() and finally, in the same function, sets the in-memory
inodes depending on xattr values, unless they are in specially-handled
filesystems.
Other than being inefficient, this also prevents filesystems not supporting
xattrs from working properly since, without xattrs, there is no way to pass
the label determined in smack_inode_init_security() to
smack_d_instantiate().
Since the LSM infrastructure allows setting and getting the security field
without xattrs through the inode_setsecurity and inode_getsecurity hooks,
make the inode creation work too, by initializing the in-memory inode
earlier in smack_inode_init_security().
Also mark the inode as instantiated, to prevent smack_d_instantiate() from
overwriting the security field. As mentioned above, this potentially has
impact for inodes in specially-handled filesystems in
smack_d_instantiate(), if they are not handled in the same way in
smack_inode_init_security().
Filesystems other than tmpfs don't call security_inode_init_security(), so
they would be always initialized in smack_d_instantiate(), as before. For
tmpfs, the current behavior is to assign to inodes the label '*', but
actually that label is overwritten with the one fetched from the SMACK64
xattr, set in smack_inode_init_security() (default: '_').
Initializing the in-memory inode is straightforward: if not transmuting,
nothing more needs to be done; if transmuting, overwrite the current inode
label with the one from the parent directory, and set SMK_INODE_TRANSMUTE.
Finally, set SMK_INODE_INSTANT for all cases, to mark the inode as
instantiated.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/smack/smack_lsm.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 2ec3f33452006e..d52d2a7a813d76 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -994,6 +994,7 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, struct xattr *xattrs, int *xattr_count) { struct task_smack *tsp = smack_cred(current_cred()); + struct inode_smack *issp = smack_inode(inode); struct smack_known *skp = smk_of_task(tsp); struct smack_known *isp = smk_of_inode(inode); struct smack_known *dsp = smk_of_inode(dir); @@ -1029,7 +1030,9 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, * smack_inode_alloc_security(). */ if (tsp->smk_task != tsp->smk_transmuted) - isp = dsp; + isp = issp->smk_inode = dsp; + + issp->smk_flags |= SMK_INODE_TRANSMUTE; xattr_transmute = lsm_get_xattr_slot(xattrs, xattr_count); if (xattr_transmute) { @@ -1044,6 +1047,8 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, } } + issp->smk_flags |= SMK_INODE_INSTANT; + if (xattr) { xattr->value = kstrdup(isp->smk_known, GFP_NOFS); if (!xattr->value) |