linux-stable.git/kernel/audit_fsnotify.c, branch v6.18.39

audit: fix removal of dangling executable rules

2026-07-18T14:53:32+00:00

commit 888a0396e154524f4027f27da84bdbec9eb68916 upstream.

When an audited executable is deleted from the disk, its dentry
becomes negative. Any later attempt to delete the associated audit
rule will lead to audit_alloc_mark() encountering this negative
dentry and immediately aborting, returning -ENOENT.

This early abort prevents the subsystem from allocating the temporary
fsnotify mark needed to construct the search key, meaning the kernel
cannot find the existing rule in its own lists to delete it. This
leaves a dangling rule in memory, resulting in the following error
while attempting to delete the rule:

 # ./audit-dupe-exe-deadlock.sh
 No rules
 Error deleting rule (No such file or directory)
 There was an error while processing parameters

 # auditctl -l
 -a always,exit -S all -F exe=/tmp/file -F path=/tmp/file -F key=dr

 # auditctl -D
 Error deleting rule (No such file or directory)
 There was an error while processing parameters

This patch fixes this issue by removing the d_really_is_negative()
check. By doing so, a dummy mark can be successfully generated for
the deleted path, which allows the audit subsystem to properly match
and flush the dangling rule.

Cc: stable@kernel.org
Fixes: 76a53de6f7ff ("VFS/audit: introduce kern_path_parent() for audit")
Acked-by: Waiman Long 
Acked-by: Richard Guy Briggs 
Signed-off-by: Ricardo Robaina 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

VFS/audit: introduce kern_path_parent() for audit

2025-09-23T10:37:35+00:00

audit_alloc_mark() and audit_get_nd() both need to perform a path
lookup getting the parent dentry (which must exist) and the final
target (following a LAST_NORM name) which sometimes doesn't need to
exist.

They don't need the parent to be locked, but use kern_path_locked() or
kern_path_locked_negative() anyway.  This is somewhat misleading to the
casual reader.

This patch introduces a more targeted function, kern_path_parent(),
which returns not holding locks.  On success the "path" will
be set to the parent, which must be found, and the return value is the
dentry of the target, which might be negative.

This will clear the way to rename kern_path_locked() which is
otherwise only used to prepare for removing something.

It also allows us to remove kern_path_locked_negative(), which is
transformed into the new kern_path_parent().

Signed-off-by: NeilBrown 
Signed-off-by: Christian Brauner

audit: fix potential double free on error path from fsnotify_add_inode_mark

2022-08-22T22:50:06+00:00

Audit_alloc_mark() assign pathname to audit_mark->path, on error path
from fsnotify_add_inode_mark(), fsnotify_put_mark will free memory
of audit_mark->path, but the caller of audit_alloc_mark will free
the pathname again, so there will be double free problem.

Fix this by resetting audit_mark->path to NULL pointer on error path
from fsnotify_add_inode_mark().

Cc: stable@vger.kernel.org
Fixes: 7b1293234084d ("fsnotify: Add group pointer in fsnotify_init_mark()")
Signed-off-by: Gaosheng Cui 
Reviewed-by: Jan Kara 
Signed-off-by: Paul Moore

fsnotify: make allow_dups a property of the group

2022-04-25T12:37:18+00:00

Instead of passing the allow_dups argument to fsnotify_add_mark()
as an argument, define the group flag FSNOTIFY_GROUP_DUPS to express
the allow_dups behavior and set this behavior at group creation time
for all calls of fsnotify_add_mark().

Rename the allow_dups argument to generic add_flags argument for future
use.

Link: https://lore.kernel.org/r/20220422120327.3459282-6-amir73il@gmail.com
Suggested-by: Jan Kara 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

fsnotify: pass flags argument to fsnotify_alloc_group()

2022-04-25T12:37:12+00:00

Add flags argument to fsnotify_alloc_group(), define and use the flag
FSNOTIFY_GROUP_USER in inotify and fanotify instead of the helper
fsnotify_alloc_user_group() to indicate user allocation.

Although the flag FSNOTIFY_GROUP_USER is currently not used after group
allocation, we store the flags argument in the group struct for future
use of other group flags.

Link: https://lore.kernel.org/r/20220422120327.3459282-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

fsnotify: clarify contract for create event hooks

2021-10-27T10:32:34+00:00

Clarify argument names and contract for fsnotify_create() and
fsnotify_mkdir() to reflect the anomaly of kernfs, which leaves dentries
negavite after mkdir/create.

Remove the WARN_ON(!inode) in audit code that were added by the Fixes
commit under the wrong assumption that dentries cannot be negative after
mkdir/create.

Fixes: aa93bdc5500c ("fsnotify: use helpers to access data by data_type")
Link: https://lore.kernel.org/linux-fsdevel/87mtp5yz0q.fsf@collabora.com/
Link: https://lore.kernel.org/r/20211025192746.66445-4-krisman@collabora.com
Reviewed-by: Jan Kara 
Reported-by: Gabriel Krisman Bertazi 
Signed-off-by: Amir Goldstein 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

audit_alloc_mark(): don't open-code ERR_CAST()

2021-02-23T15:25:27+00:00

Signed-off-by: Al Viro

fsnotify: generalize handle_inode_event()

2020-12-03T13:58:35+00:00

The handle_inode_event() interface was added as (quoting comment):
"a simple variant of handle_event() for groups that only have inode
marks and don't have ignore mask".

In other words, all backends except fanotify.  The inotify backend
also falls under this category, but because it required extra arguments
it was left out of the initial pass of backends conversion to the
simple interface.

This results in code duplication between the generic helper
fsnotify_handle_event() and the inotify_handle_event() callback
which also happen to be buggy code.

Generalize the handle_inode_event() arguments and add the check for
FS_EXCL_UNLINK flag to the generic helper, so inotify backend could
be converted to use the simple interface.

Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com
CC: stable@vger.kernel.org
Fixes: b9a1b9772509 ("fsnotify: create method handle_inode_event() in fsnotify_operations")
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

fsnotify: create method handle_inode_event() in fsnotify_operations

2020-07-27T21:25:50+00:00

The method handle_event() grew a lot of complexity due to the design of
fanotify and merging of ignore masks.

Most backends do not care about this complex functionality, so we can hide
this complexity from them.

Introduce a method handle_inode_event() that serves those backends and
passes a single inode mark and less arguments.

This change converts all backends except fanotify and inotify to use the
simplified handle_inode_event() method.  In pricipal, inotify could have
also used the new method, but that would require passing more arguments
on the simple helper (data, data_type, cookie), so we leave it with the
handle_event() method.

Link: https://lore.kernel.org/r/20200722125849.17418-9-amir73il@gmail.com
Suggested-by: Jan Kara 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

audit: do not set FS_EVENT_ON_CHILD in audit marks mask

2020-07-27T21:16:33+00:00

The audit group marks mask does not contain any events possible on
a child so setting the flag FS_EVENT_ON_CHILD in the mask is counter
productive.

It may lead to the undesired outcome of setting the dentry flag
DCACHE_FSNOTIFY_PARENT_WATCHED on a directory inode even though it is
not watching children, because the audit mark contribute the flag
FS_EVENT_ON_CHILD to the inode's fsnotify_mask and another mark could
be contributing an event that is possible on child to the inode's mask.

Furthermore in the following patches we want to use FS_EVENT_ON_CHILD
for non-dir inodes for other purposes so stop using the flag.

Link: https://lore.kernel.org/r/20200722125849.17418-4-amir73il@gmail.com
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara