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Vulnerability CVE-2024-41012
Published: 2024-07-23
| Description: |
In the Linux kernel, the following vulnerability has been resolved:
filelock: Remove locks reliably when fcntl/close race is detected
When fcntl_setlk() races with close(), it removes the created lock with
do_lock_file_wait().
However, LSMs can allow the first do_lock_file_wait() that created the lock
while denying the second do_lock_file_wait() that tries to remove the lock.
Separately, posix_lock_file() could also fail to
remove a lock due to GFP_KERNEL allocation failure (when splitting a range
in the middle).
After the bug has been triggered, use-after-free reads will occur in
lock_get_status() when userspace reads /proc/locks. This can likely be used
to read arbitrary kernel memory, but can't corrupt kernel memory.
Fix it by calling locks_remove_posix() instead, which is designed to
reliably get rid of POSIX locks associated with the given file and
files_struct and is also used by filp_flush(). |
References: |
https://git.kernel.org/stable/c/b6d223942c34057fdfd8f149e763fa823731b224
https://git.kernel.org/stable/c/3cad1bc010416c6dd780643476bc59ed742436b9
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