CVE Published: 23/07/2024 |
CVE Updated: 05/11/2024 |
CVE Year: 2024 Source: Linux |
Vendor: Linux |
Product: Linux Status : PUBLISHED
CVE-2024-41012 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().