Bugzilla – Bug 1228247
VUL-0: CVE-2024-41012: kernel: filelock: Remove locks reliably when fcntl/close race is detected
Last modified: 2024-07-24 12:02:56 UTC
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: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-41012 https://www.cve.org/CVERecord?id=CVE-2024-41012 https://git.kernel.org/stable/c/3cad1bc010416c6dd780643476bc59ed742436b9 https://git.kernel.org/stable/c/b6d223942c34057fdfd8f149e763fa823731b224 https://bugzilla.redhat.com/show_bug.cgi?id=2299452 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-41012.mbox