Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: gfs2: fix use-after-free in gfs2_qd_dealloc gfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(), accesses the superblock object sdp through qd->qd_sbd after freeing qd. It does so to decrement sd_quota_count and wake up sd_kill_wait. However, by the time the RCU callback runs, gfs2_put_super() may have already freed sdp via free_sbd(). This can happen when gfs2_quota_cleanup() is called during unmount: it disposes of quota objects via call_rcu() and then waits on sd_kill_wait with a 60-second timeout. If the timeout expires, or if gfs2_gl_hash_clear() triggers additional qd_put() calls that schedule more RCU callbacks after the wait completes, gfs2_put_super() will proceed to free the superblock while RCU callbacks referencing it are still pending. Add an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure all pending RCU callbacks (including gfs2_qd_dealloc) have completed before the superblock is freed.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected a475c5dd16e57c570113eccba51955b5df8bb052 before 4fe388218826df8607ae41a6305df67db08a9093; affected a475c5dd16e57c570113eccba51955b5df8bb052 before 8745d9f7e1682c39f0a1578895ac74205e2a6757; affected a475c5dd16e57c570113eccba51955b5df8bb052 before b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0; affected a475c5dd16e57c570113eccba51955b5df8bb052 before 9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0; affected a475c5dd16e57c570113eccba51955b5df8bb052 before f9c9ec2c319f843b70ecdf939d48b52d189bc081 |
| Linux / Linux | affected 6.6; unaffected 0 before 6.6; unaffected 6.6.144 through 6.6.*; unaffected 6.12.95 through 6.12.*; unaffected 6.18.38 through 6.18.*; unaffected 7.1.3 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/4fe388218826df8607ae41a6305df67db08a9093
- https://git.kernel.org/stable/c/8745d9f7e1682c39f0a1578895ac74205e2a6757
- https://git.kernel.org/stable/c/b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0
- https://git.kernel.org/stable/c/9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0
- https://git.kernel.org/stable/c/f9c9ec2c319f843b70ecdf939d48b52d189bc081