Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ceph: fix UAF in check_new_map() on session freed during unlock check_new_map() iterates mdsc->sessions[] and for each active session drops mdsc->mutex to perform per-session operations. The forced-close path (rank removed from map) correctly takes a reference on s via ceph_get_mds_session() before releasing mdsc->mutex, but three other paths do not: Path A (address changed): mutex_unlock → mutex_lock(&s->s_mutex) Path B (reconnect): mutex_unlock → send_mds_reconnect(mdsc, s) Path C (active transition): mutex_unlock → mutex_lock(&s->s_mutex) Without the extra reference, another thread can acquire mdsc->mutex during the unlock window, call __unregister_session() which drops the last reference on s, and free it. The original thread then accesses freed memory via s->s_mutex. Fix by adding ceph_get_mds_session(s) before each mutex_unlock and ceph_put_mds_session(s) after the corresponding mutex_lock, matching the pattern already used in the forced-close path. Race timeline (Path A): Thread A (check_new_map) Thread B (another map update holds mdsc->mutex or session teardown) -------------------------- -------------------------- s = mdsc->sessions[i] (refcount == 1, held only by sessions[] array) mutex_unlock(&mdsc->mutex) ---> acquires mdsc->mutex __unregister_session(mdsc, s) sessions[i] = NULL ceph_put_mds_session(s) refcount: 1 -> 0 kfree(s) <--- freed! mutex_lock(&s->s_mutex) UAF on freed s->s_mutex
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 2f2dc053404febedc9c273452d9d518fb31fde72 before 352a278d5a1965aae3f817ce5d24a67ee42d45d1; affected 2f2dc053404febedc9c273452d9d518fb31fde72 before 820871e9dbeecd2533c4c5f5d91878ceaf02324c; affected 2f2dc053404febedc9c273452d9d518fb31fde72 before 9646dfee880730aae4b379a4b8ee6c88ac735acd; affected 2f2dc053404febedc9c273452d9d518fb31fde72 before 21d5be092d947f8d83f76f7ebf3989e7e9230a98; affected 2f2dc053404febedc9c273452d9d518fb31fde72 before ee611a7509554c4ca1f54f6aefe592fb1df7ea70 |
| Linux / Linux | affected 2.6.34; unaffected 0 before 2.6.34; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.2.4 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/352a278d5a1965aae3f817ce5d24a67ee42d45d1
- https://git.kernel.org/stable/c/820871e9dbeecd2533c4c5f5d91878ceaf02324c
- https://git.kernel.org/stable/c/9646dfee880730aae4b379a4b8ee6c88ac735acd
- https://git.kernel.org/stable/c/21d5be092d947f8d83f76f7ebf3989e7e9230a98
- https://git.kernel.org/stable/c/ee611a7509554c4ca1f54f6aefe592fb1df7ea70
ADP enrichment
No English description supplied.
No references supplied.