linux-stable.git/security, branch v6.18.2 Linux kernel stable tree landlock: Fix handling of disconnected directories 2025-12-18T13:03:27+00:00 Mickaël Salaün mic@digikod.net 2025-11-28T17:21:56+00:00 cadb28f8b3fd6908e3051e86158c65c3a8e1c907 [ Upstream commit 49c9e09d961025b22e61ef9ad56aa1c21b6ce2f1 ] Disconnected files or directories can appear when they are visible and opened from a bind mount, but have been renamed or moved from the source of the bind mount in a way that makes them inaccessible from the mount point (i.e. out of scope). Previously, access rights tied to files or directories opened through a disconnected directory were collected by walking the related hierarchy down to the root of the filesystem, without taking into account the mount point because it couldn't be found. This could lead to inconsistent access results, potential access right widening, and hard-to-debug renames, especially since such paths cannot be printed. For a sandboxed task to create a disconnected directory, it needs to have write access (i.e. FS_MAKE_REG, FS_REMOVE_FILE, and FS_REFER) to the underlying source of the bind mount, and read access to the related mount point. Because a sandboxed task cannot acquire more access rights than those defined by its Landlock domain, this could lead to inconsistent access rights due to missing permissions that should be inherited from the mount point hierarchy, while inheriting permissions from the filesystem hierarchy hidden by this mount point instead. Landlock now handles files and directories opened from disconnected directories by taking into account the filesystem hierarchy when the mount point is not found in the hierarchy walk, and also always taking into account the mount point from which these disconnected directories were opened. This ensures that a rename is not allowed if it would widen access rights [1]. The rationale is that, even if disconnected hierarchies might not be visible or accessible to a sandboxed task, relying on the collected access rights from them improves the guarantee that access rights will not be widened during a rename because of the access right comparison between the source and the destination (see LANDLOCK_ACCESS_FS_REFER). It may look like this would grant more access on disconnected files and directories, but the security policies are always enforced for all the evaluated hierarchies. This new behavior should be less surprising to users and safer from an access control perspective. Remove a wrong WARN_ON_ONCE() canary in collect_domain_accesses() and fix the related comment. Because opened files have their access rights stored in the related file security properties, there is no impact for disconnected or unlinked files. Cc: Christian Brauner <brauner@kernel.org> Cc: Günther Noack <gnoack@google.com> Cc: Song Liu <song@kernel.org> Reported-by: Tingmao Wang <m@maowtm.org> Closes: https://lore.kernel.org/r/027d5190-b37a-40a8-84e9-4ccbc352bcdf@maowtm.org Closes: https://lore.kernel.org/r/09b24128f86973a6022e6aa8338945fcfb9a33e4.1749925391.git.m@maowtm.org Fixes: b91c3e4ea756 ("landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER") Fixes: cb2c7d1a1776 ("landlock: Support filesystem access-control") Link: https://lore.kernel.org/r/b0f46246-f2c5-42ca-93ce-0d629702a987@maowtm.org [1] Reviewed-by: Tingmao Wang <m@maowtm.org> Link: https://lore.kernel.org/r/20251128172200.760753-2-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 49c9e09d961025b22e61ef9ad56aa1c21b6ce2f1 ]

Disconnected files or directories can appear when they are visible and
opened from a bind mount, but have been renamed or moved from the source
of the bind mount in a way that makes them inaccessible from the mount
point (i.e. out of scope).

Previously, access rights tied to files or directories opened through a
disconnected directory were collected by walking the related hierarchy
down to the root of the filesystem, without taking into account the
mount point because it couldn't be found. This could lead to
inconsistent access results, potential access right widening, and
hard-to-debug renames, especially since such paths cannot be printed.

For a sandboxed task to create a disconnected directory, it needs to
have write access (i.e. FS_MAKE_REG, FS_REMOVE_FILE, and FS_REFER) to
the underlying source of the bind mount, and read access to the related
mount point.   Because a sandboxed task cannot acquire more access
rights than those defined by its Landlock domain, this could lead to
inconsistent access rights due to missing permissions that should be
inherited from the mount point hierarchy, while inheriting permissions
from the filesystem hierarchy hidden by this mount point instead.

Landlock now handles files and directories opened from disconnected
directories by taking into account the filesystem hierarchy when the
mount point is not found in the hierarchy walk, and also always taking
into account the mount point from which these disconnected directories
were opened.  This ensures that a rename is not allowed if it would
widen access rights [1].

The rationale is that, even if disconnected hierarchies might not be
visible or accessible to a sandboxed task, relying on the collected
access rights from them improves the guarantee that access rights will
not be widened during a rename because of the access right comparison
between the source and the destination (see LANDLOCK_ACCESS_FS_REFER).
It may look like this would grant more access on disconnected files and
directories, but the security policies are always enforced for all the
evaluated hierarchies.  This new behavior should be less surprising to
users and safer from an access control perspective.

Remove a wrong WARN_ON_ONCE() canary in collect_domain_accesses() and
fix the related comment.

Because opened files have their access rights stored in the related file
security properties, there is no impact for disconnected or unlinked
files.

Cc: Christian Brauner <brauner@kernel.org>
Cc: Günther Noack <gnoack@google.com>
Cc: Song Liu <song@kernel.org>
Reported-by: Tingmao Wang <m@maowtm.org>
Closes: https://lore.kernel.org/r/027d5190-b37a-40a8-84e9-4ccbc352bcdf@maowtm.org
Closes: https://lore.kernel.org/r/09b24128f86973a6022e6aa8338945fcfb9a33e4.1749925391.git.m@maowtm.org
Fixes: b91c3e4ea756 ("landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER")
Fixes: cb2c7d1a1776 ("landlock: Support filesystem access-control")
Link: https://lore.kernel.org/r/b0f46246-f2c5-42ca-93ce-0d629702a987@maowtm.org [1]
Reviewed-by: Tingmao Wang <m@maowtm.org>
Link: https://lore.kernel.org/r/20251128172200.760753-2-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ima: Handle error code returned by ima_filter_rule_match() 2025-12-18T13:03:10+00:00 Zhao Yipeng zhaoyipeng5@huawei.com 2025-11-20T07:18:05+00:00 32952c4f4d1b2deb30dce72ba109da808a9018e1 [ Upstream commit 738c9738e690f5cea24a3ad6fd2d9a323cf614f6 ] In ima_match_rules(), if ima_filter_rule_match() returns -ENOENT due to the rule being NULL, the function incorrectly skips the 'if (!rc)' check and sets 'result = true'. The LSM rule is considered a match, causing extra files to be measured by IMA. This issue can be reproduced in the following scenario: After unloading the SELinux policy module via 'semodule -d', if an IMA measurement is triggered before ima_lsm_rules is updated, in ima_match_rules(), the first call to ima_filter_rule_match() returns -ESTALE. This causes the code to enter the 'if (rc == -ESTALE && !rule_reinitialized)' block, perform ima_lsm_copy_rule() and retry. In ima_lsm_copy_rule(), since the SELinux module has been removed, the rule becomes NULL, and the second call to ima_filter_rule_match() returns -ENOENT. This bypasses the 'if (!rc)' check and results in a false match. Call trace: selinux_audit_rule_match+0x310/0x3b8 security_audit_rule_match+0x60/0xa0 ima_match_rules+0x2e4/0x4a0 ima_match_policy+0x9c/0x1e8 ima_get_action+0x48/0x60 process_measurement+0xf8/0xa98 ima_bprm_check+0x98/0xd8 security_bprm_check+0x5c/0x78 search_binary_handler+0x6c/0x318 exec_binprm+0x58/0x1b8 bprm_execve+0xb8/0x130 do_execveat_common.isra.0+0x1a8/0x258 __arm64_sys_execve+0x48/0x68 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0xc8/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x44/0x200 el0t_64_sync_handler+0x100/0x130 el0t_64_sync+0x3c8/0x3d0 Fix this by changing 'if (!rc)' to 'if (rc <= 0)' to ensure that error codes like -ENOENT do not bypass the check and accidentally result in a successful match. Fixes: 4af4662fa4a9d ("integrity: IMA policy") Signed-off-by: Zhao Yipeng <zhaoyipeng5@huawei.com> Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 738c9738e690f5cea24a3ad6fd2d9a323cf614f6 ]

In ima_match_rules(), if ima_filter_rule_match() returns -ENOENT due to
the rule being NULL, the function incorrectly skips the 'if (!rc)' check
and sets 'result = true'. The LSM rule is considered a match, causing
extra files to be measured by IMA.

This issue can be reproduced in the following scenario:
After unloading the SELinux policy module via 'semodule -d', if an IMA
measurement is triggered before ima_lsm_rules is updated,
in ima_match_rules(), the first call to ima_filter_rule_match() returns
-ESTALE. This causes the code to enter the 'if (rc == -ESTALE &&
!rule_reinitialized)' block, perform ima_lsm_copy_rule() and retry. In
ima_lsm_copy_rule(), since the SELinux module has been removed, the rule
becomes NULL, and the second call to ima_filter_rule_match() returns
-ENOENT. This bypasses the 'if (!rc)' check and results in a false match.

Call trace:
  selinux_audit_rule_match+0x310/0x3b8
  security_audit_rule_match+0x60/0xa0
  ima_match_rules+0x2e4/0x4a0
  ima_match_policy+0x9c/0x1e8
  ima_get_action+0x48/0x60
  process_measurement+0xf8/0xa98
  ima_bprm_check+0x98/0xd8
  security_bprm_check+0x5c/0x78
  search_binary_handler+0x6c/0x318
  exec_binprm+0x58/0x1b8
  bprm_execve+0xb8/0x130
  do_execveat_common.isra.0+0x1a8/0x258
  __arm64_sys_execve+0x48/0x68
  invoke_syscall+0x50/0x128
  el0_svc_common.constprop.0+0xc8/0xf0
  do_el0_svc+0x24/0x38
  el0_svc+0x44/0x200
  el0t_64_sync_handler+0x100/0x130
  el0t_64_sync+0x3c8/0x3d0

Fix this by changing 'if (!rc)' to 'if (rc <= 0)' to ensure that error
codes like -ENOENT do not bypass the check and accidentally result in a
successful match.

Fixes: 4af4662fa4a9d ("integrity: IMA policy")
Signed-off-by: Zhao Yipeng <zhaoyipeng5@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ima: Attach CREDS_CHECK IMA hook to bprm_creds_from_file LSM hook 2025-12-18T13:02:27+00:00 Roberto Sassu roberto.sassu@huawei.com 2025-10-08T11:35:03+00:00 d07b4af12015cc136f2795bb88ef4d7b869aa9d1 [ Upstream commit 8f3fc4f3f8aa6e99266c69cc78bdaa58379e65fc ] Since commit 56305aa9b6fa ("exec: Compute file based creds only once"), the credentials to be applied to the process after execution are not calculated anymore for each step of finding intermediate interpreters (including the final binary), but only after the final binary to be executed without interpreter has been found. In particular, that means that the bprm_check_security LSM hook will not see the updated cred->e[ug]id for the intermediate and for the final binary to be executed, since the function doing this task has been moved from prepare_binprm(), which calls the bprm_check_security hook, to bprm_creds_from_file(). This breaks the IMA expectation for the CREDS_CHECK hook, introduced with commit d906c10d8a31 ("IMA: Support using new creds in appraisal policy"), which expects to evaluate "the credentials that will be committed when the new process is started". This is clearly not the case for the CREDS_CHECK IMA hook, which is attached to bprm_check_security. This issue does not affect systems which load a policy with the BPRM_CHECK hook with no other criteria, as is the case with the built-in "tcb" and/or "appraise_tcb" IMA policies. The "tcb" built-in policy measures all executions regardless of the new credentials, and the "appraise_tcb" policy is written in terms of the file owner, rather than IMA hooks. However, it does affect systems without a BPRM_CHECK policy rule or with a BPRM_CHECK policy rule that does not include what CREDS_CHECK evaluates. As an extreme example, taking a standalone rule like: measure func=CREDS_CHECK euid=0 This will not measure for example sudo (because CREDS_CHECK still sees the bprm->cred->euid set to the regular user UID), but only the subsequent commands after the euid was applied to the children. Make set[ug]id programs measured/appraised again by splitting ima_bprm_check() in two separate hook implementations (CREDS_CHECK now being implemented by ima_creds_check()), and by attaching CREDS_CHECK to the bprm_creds_from_file LSM hook. The limitation of this approach is that CREDS_CHECK will not be invoked anymore for the intermediate interpreters, like it was before, but only for the final binary. This limitation can be removed only by reverting commit 56305aa9b6fa ("exec: Compute file based creds only once"). Link: https://github.com/linux-integrity/linux/issues/3 Fixes: 56305aa9b6fa ("exec: Compute file based creds only once") Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jann Horn <jannh@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8f3fc4f3f8aa6e99266c69cc78bdaa58379e65fc ]

Since commit 56305aa9b6fa ("exec: Compute file based creds only once"), the
credentials to be applied to the process after execution are not calculated
anymore for each step of finding intermediate interpreters (including the
final binary), but only after the final binary to be executed without
interpreter has been found.

In particular, that means that the bprm_check_security LSM hook will not
see the updated cred->e[ug]id for the intermediate and for the final binary
to be executed, since the function doing this task has been moved from
prepare_binprm(), which calls the bprm_check_security hook, to
bprm_creds_from_file().

This breaks the IMA expectation for the CREDS_CHECK hook, introduced with
commit d906c10d8a31 ("IMA: Support using new creds in appraisal policy"),
which expects to evaluate "the credentials that will be committed when the
new process is started". This is clearly not the case for the CREDS_CHECK
IMA hook, which is attached to bprm_check_security.

This issue does not affect systems which load a policy with the BPRM_CHECK
hook with no other criteria, as is the case with the built-in "tcb" and/or
"appraise_tcb" IMA policies. The "tcb" built-in policy measures all
executions regardless of the new credentials, and the "appraise_tcb" policy
is written in terms of the file owner, rather than IMA hooks.

However, it does affect systems without a BPRM_CHECK policy rule or with a
BPRM_CHECK policy rule that does not include what CREDS_CHECK evaluates. As
an extreme example, taking a standalone rule like:

measure func=CREDS_CHECK euid=0

This will not measure for example sudo (because CREDS_CHECK still sees the
bprm->cred->euid set to the regular user UID), but only the subsequent
commands after the euid was applied to the children.

Make set[ug]id programs measured/appraised again by splitting
ima_bprm_check() in two separate hook implementations (CREDS_CHECK now
being implemented by ima_creds_check()), and by attaching CREDS_CHECK to
the bprm_creds_from_file LSM hook.

The limitation of this approach is that CREDS_CHECK will not be invoked
anymore for the intermediate interpreters, like it was before, but only for
the final binary. This limitation can be removed only by reverting commit
56305aa9b6fa ("exec: Compute file based creds only once").

Link: https://github.com/linux-integrity/linux/issues/3
Fixes: 56305aa9b6fa ("exec: Compute file based creds only once")
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jann Horn <jannh@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: fix bug: setting task label silently ignores input garbage 2025-12-18T13:02:25+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T21:32:17+00:00 cf008f5bd3d5db210d1edd244e7cd1d879cb1a5e [ Upstream commit 674e2b24791cbe8fd5dc8a0aed4cb4404fcd2028 ] This command: # echo foo/bar >/proc/$$/attr/smack/current gives the task a label 'foo' w/o indication that label does not match input. Setting the label with lsm_set_self_attr() syscall behaves identically. This occures because: 1) smk_parse_smack() is used to convert input to a label 2) smk_parse_smack() takes only that part from the beginning of the input that looks like a label. 3) `/' is prohibited in labels, so only "foo" is taken. (2) is by design, because smk_parse_smack() is used for parsing strings which are more than just a label. Silent failure is not a good thing, and there are two indicators that this was not done intentionally: (size >= SMK_LONGLABEL) ~> invalid clause at the beginning of the do_setattr() and the "Returns the length of the smack label" claim in the do_setattr() description. So I fixed this by adding one tiny check: the taken label length == input length. Since input length is now strictly controlled, I changed the two ways of setting label smack_setselfattr(): lsm_set_self_attr() syscall smack_setprocattr(): > /proc/.../current to accommodate the divergence in what they understand by "input length": smack_setselfattr counts mandatory \0 into input length, smack_setprocattr does not. smack_setprocattr allows various trailers after label Related changes: * fixed description for smk_parse_smack * allow unprivileged tasks validate label syntax. * extract smk_parse_label_len() from smk_parse_smack() so parsing may be done w/o string allocation. * extract smk_import_valid_label() from smk_import_entry() to avoid repeated parsing. * smk_parse_smack(): scan null-terminated strings for no more than SMK_LONGLABEL(256) characters * smack_setselfattr(): require struct lsm_ctx . flags == 0 to reserve them for future. Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel") Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 674e2b24791cbe8fd5dc8a0aed4cb4404fcd2028 ]

This command:
    # echo foo/bar >/proc/$$/attr/smack/current

gives the task a label 'foo' w/o indication
that label does not match input.
Setting the label with lsm_set_self_attr() syscall
behaves identically.

This occures because:

1) smk_parse_smack() is used to convert input to a label
2) smk_parse_smack() takes only that part from the
   beginning of the input that looks like a label.
3) `/' is prohibited in labels, so only "foo" is taken.

(2) is by design, because smk_parse_smack() is used
for parsing strings which are more than just a label.

Silent failure is not a good thing, and there are two
indicators that this was not done intentionally:

    (size >= SMK_LONGLABEL) ~> invalid

clause at the beginning of the do_setattr() and the
"Returns the length of the smack label" claim
in the do_setattr() description.

So I fixed this by adding one tiny check:
the taken label length == input length.

Since input length is now strictly controlled,
I changed the two ways of setting label

   smack_setselfattr(): lsm_set_self_attr() syscall
   smack_setprocattr(): > /proc/.../current

to accommodate the divergence in
what they understand by "input length":

  smack_setselfattr counts mandatory \0 into input length,
  smack_setprocattr does not.

  smack_setprocattr allows various trailers after label

Related changes:

* fixed description for smk_parse_smack

* allow unprivileged tasks validate label syntax.

* extract smk_parse_label_len() from smk_parse_smack()
  so parsing may be done w/o string allocation.

* extract smk_import_valid_label() from smk_import_entry()
  to avoid repeated parsing.

* smk_parse_smack(): scan null-terminated strings
  for no more than SMK_LONGLABEL(256) characters

* smack_setselfattr(): require struct lsm_ctx . flags == 0
  to reserve them for future.

Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel")
Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: fix bug: unprivileged task can create labels 2025-12-18T13:02:25+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T21:32:16+00:00 60e8d49989410a7ade60f5dadfcd979c117d05c0 [ Upstream commit c147e13ea7fe9f118f8c9ba5e96cbd644b00d6b3 ] If an unprivileged task is allowed to relabel itself (/smack/relabel-self is not empty), it can freely create new labels by writing their names into own /proc/PID/attr/smack/current This occurs because do_setattr() imports the provided label in advance, before checking "relabel-self" list. This change ensures that the "relabel-self" list is checked before importing the label. Fixes: 38416e53936e ("Smack: limited capability for changing process label") Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c147e13ea7fe9f118f8c9ba5e96cbd644b00d6b3 ]

If an unprivileged task is allowed to relabel itself
(/smack/relabel-self is not empty),
it can freely create new labels by writing their
names into own /proc/PID/attr/smack/current

This occurs because do_setattr() imports
the provided label in advance,
before checking "relabel-self" list.

This change ensures that the "relabel-self" list
is checked before importing the label.

Fixes: 38416e53936e ("Smack: limited capability for changing process label")
Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: fix bug: invalid label of unix socket file 2025-12-18T13:02:25+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T01:07:32+00:00 70c5be42f691fb6b46084bdf42e191cab0e9dde7 [ Upstream commit 78fc6a94be252b27bb73e4926eed70b5e302a8e0 ] According to [1], the label of a UNIX domain socket (UDS) file (i.e., the filesystem object representing the socket) is not supposed to participate in Smack security. To achieve this, [1] labels UDS files with "*" in smack_d_instantiate(). Before [2], smack_d_instantiate() was responsible for initializing Smack security for all inodes, except ones under /proc [2] imposed the sole responsibility for initializing inode security for newly created filesystem objects on smack_inode_init_security(). However, smack_inode_init_security() lacks some logic present in smack_d_instantiate(). In particular, it does not label UDS files with "*". This patch adds the missing labeling of UDS files with "*" to smack_inode_init_security(). Labeling UDS files with "*" in smack_d_instantiate() still works for stale UDS files that already exist on disk. Stale UDS files are useless, but I keep labeling them for consistency and maybe to make easier for user to delete them. Compared to [1], this version introduces the following improvements: * UDS file label is held inside inode only and not saved to xattrs. * relabeling UDS files (setxattr, removexattr, etc.) is blocked. [1] 2010-11-24 Casey Schaufler commit b4e0d5f0791b ("Smack: UDS revision") [2] 2023-11-16 roberto.sassu Fixes: e63d86b8b764 ("smack: Initialize the in-memory inode in smack_inode_init_security()") Link: https://lore.kernel.org/linux-security-module/20231116090125.187209-5-roberto.sassu@huaweicloud.com/ Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 78fc6a94be252b27bb73e4926eed70b5e302a8e0 ]

According to [1], the label of a UNIX domain socket (UDS)
file (i.e., the filesystem object representing the socket)
is not supposed to participate in Smack security.

To achieve this, [1] labels UDS files with "*"
in smack_d_instantiate().

Before [2], smack_d_instantiate() was responsible
for initializing Smack security for all inodes,
except ones under /proc

[2] imposed the sole responsibility for initializing
inode security for newly created filesystem objects
on smack_inode_init_security().

However, smack_inode_init_security() lacks some logic
present in smack_d_instantiate().
In particular, it does not label UDS files with "*".

This patch adds the missing labeling of UDS files
with "*" to smack_inode_init_security().

Labeling UDS files with "*" in smack_d_instantiate()
still works for stale UDS files that already exist on
disk. Stale UDS files are useless, but I keep labeling
them for consistency and maybe to make easier for user
to delete them.

Compared to [1], this version introduces the following
improvements:

  * UDS file label is held inside inode only
    and not saved to xattrs.

  * relabeling UDS files (setxattr, removexattr, etc.)
    is blocked.

[1] 2010-11-24 Casey Schaufler
commit b4e0d5f0791b ("Smack: UDS revision")

[2] 2023-11-16 roberto.sassu
Fixes: e63d86b8b764 ("smack: Initialize the in-memory inode in smack_inode_init_security()")
Link: https://lore.kernel.org/linux-security-module/20231116090125.187209-5-roberto.sassu@huaweicloud.com/

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: always "instantiate" inode in smack_inode_init_security() 2025-12-18T13:02:25+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T01:07:31+00:00 f1dbb370eca563582f90744618e6eaa95335fde6 [ Upstream commit 69204f6cdb90f56b7ca27966d1080841108fc5de ] If memory allocation for the SMACK64TRANSMUTE xattr value fails in smack_inode_init_security(), the SMK_INODE_INSTANT flag is not set in (struct inode_smack *issp)->smk_flags, leaving the inode as not "instantiated". It does not matter if fs frees the inode after failed smack_inode_init_security() call, but there is no guarantee for this. To be safe, mark the inode as "instantiated", even if allocation of xattr values fails. Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 69204f6cdb90f56b7ca27966d1080841108fc5de ]

If memory allocation for the SMACK64TRANSMUTE
xattr value fails in smack_inode_init_security(),
the SMK_INODE_INSTANT flag is not set in
(struct inode_smack *issp)->smk_flags,
leaving the inode as not "instantiated".

It does not matter if fs frees the inode
after failed smack_inode_init_security() call,
but there is no guarantee for this.

To be safe, mark the inode as "instantiated",
even if allocation of xattr values fails.

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file")
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: deduplicate xattr setting in smack_inode_init_security() 2025-12-18T13:02:24+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T01:07:30+00:00 3c4f1ca5bd912d08d33415bf537f99adeb1a9708 [ Upstream commit 8e5d9f916a9678e2dcbed2289b87efd453e4e052 ] Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8e5d9f916a9678e2dcbed2289b87efd453e4e052 ]

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file")
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: deduplicate "does access rule request transmutation" 2025-12-18T13:02:24+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T01:07:28+00:00 06025d5e707f760992946f17af403831d5a6347c [ Upstream commit 635a01da8385fc00a144ec24684100bd1aa9db11 ] Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 635a01da8385fc00a144ec24684100bd1aa9db11 ]

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file")
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: fix bug: SMACK64TRANSMUTE set on non-directory 2025-12-18T13:02:24+00:00 Konstantin Andreev andreev@swemel.ru 2025-06-16T01:07:29+00:00 cf036137162c1f227e8e488d3a60b99894853593 [ Upstream commit 195da3ff244deff119c3f5244b464b2236ea1725 ] When a new file system object is created and the conditions for label transmutation are met, the SMACK64TRANSMUTE extended attribute is set on the object regardless of its type: file, pipe, socket, symlink, or directory. However, SMACK64TRANSMUTE may only be set on directories. This bug is a combined effect of the commits [1] and [2] which both transfer functionality from smack_d_instantiate() to smack_inode_init_security(), but only in part. Commit [1] set blank SMACK64TRANSMUTE on improper object types. Commit [2] set "TRUE" SMACK64TRANSMUTE on improper object types. [1] 2023-06-10, Fixes: baed456a6a2f ("smack: Set the SMACK64TRANSMUTE xattr in smack_inode_init_security()") Link: https://lore.kernel.org/linux-security-module/20230610075738.3273764-3-roberto.sassu@huaweicloud.com/ [2] 2023-11-16, Fixes: e63d86b8b764 ("smack: Initialize the in-memory inode in smack_inode_init_security()") Link: https://lore.kernel.org/linux-security-module/20231116090125.187209-5-roberto.sassu@huaweicloud.com/ Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 195da3ff244deff119c3f5244b464b2236ea1725 ]

When a new file system object is created
and the conditions for label transmutation are met,
the SMACK64TRANSMUTE extended attribute is set
on the object regardless of its type:
file, pipe, socket, symlink, or directory.

However,
SMACK64TRANSMUTE may only be set on directories.

This bug is a combined effect of the commits [1] and [2]
which both transfer functionality
from smack_d_instantiate() to smack_inode_init_security(),
but only in part.

Commit [1] set blank  SMACK64TRANSMUTE on improper object types.
Commit [2] set "TRUE" SMACK64TRANSMUTE on improper object types.

[1] 2023-06-10,
Fixes: baed456a6a2f ("smack: Set the SMACK64TRANSMUTE xattr in smack_inode_init_security()")
Link: https://lore.kernel.org/linux-security-module/20230610075738.3273764-3-roberto.sassu@huaweicloud.com/

[2] 2023-11-16,
Fixes: e63d86b8b764 ("smack: Initialize the in-memory inode in smack_inode_init_security()")
Link: https://lore.kernel.org/linux-security-module/20231116090125.187209-5-roberto.sassu@huaweicloud.com/

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>