Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: futex: Clear stale exiting pointer in futex_lock_pi() retry path Fuzzying/stressing futexes triggered: WARNING: kernel/futex/core.c:825 at wait_for_owner_exiting+0x7a/0x80, CPU#11: futex_lock_pi_s/524 When futex_lock_pi_atomic() sees the owner is exiting, it returns -EBUSY and stores a refcounted task pointer in 'exiting'. After wait_for_owner_exiting() consumes that reference, the local pointer is never reset to nil. Upon a retry, if futex_lock_pi_atomic() returns a different error, the bogus pointer is passed to wait_for_owner_exiting(). CPU0 CPU1 CPU2 futex_lock_pi(uaddr) // acquires the PI futex exit() futex_cleanup_begin() futex_state = EXITING; futex_lock_pi(uaddr) futex_lock_pi_atomic() attach_to_pi_owner() // observes EXITING *exiting = owner; // takes ref return -EBUSY wait_for_owner_exiting(-EBUSY, owner) put_task_struct(); // drops ref // exiting still points to owner goto retry; futex_lock_pi_atomic() lock_pi_update_atomic() cmpxchg(uaddr) *uaddr ^= WAITERS // whatever // value changed return -EAGAIN; wait_for_owner_exiting(-EAGAIN, exiting) // stale WARN_ON_ONCE(exiting) Fix this by resetting upon retry, essentially aligning it with requeue_pi.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before 33095ae3bdde5e5c264d7e88a2f3e7703a26c7aa; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before e7824ec168d2ac883a213cd1f4d6cc0816002a85; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before 5e8e06bf8909e79b4acd950cf578cfc2f10bbefa; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before de7c0c04ad868f2cee6671b11c0a6d20421af1da; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before 7475dfad10a05a5bfadebf5f2499bd61b19ed293; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before 92e47ad03e03dbb5515bdf06444bf6b1e147310d; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before 71112e62807d1925dc3ae6188b11f8cfc85aec23; affected 3ef240eaff36b8119ac9e2ea17cbf41179c930ba before 210d36d892de5195e6766c45519dfb1e65f3eb83; affected f2a9957e5c08b1b1caacd18a3dc4c0a1bdb7b463; affected cf16e42709aa86aa3e37f3acc3d13d5715d90096; affected 61fa9f167caaa73d0a7c88f498eceeb12c6fa3db; affected 7874eee0130adf9bee28e8720bb5dd051089def3; affected fc3b55ef2c840bb2746b2d8121a0788de84f7fac; affected 4.4.255 before 4.5; affected 4.9.255 before 4.10; affected 4.14.158 before 4.15; affected 4.19.172 before 4.20; affected 5.4.1 before 5.5 |
| Linux / Linux | affected 5.5; unaffected 0 before 5.5; unaffected 5.10.253 through 5.10.*; unaffected 5.15.203 through 5.15.*; unaffected 6.1.168 through 6.1.*; unaffected 6.6.131 through 6.6.*; unaffected 6.12.80 through 6.12.*; unaffected 6.18.21 through 6.18.*; unaffected 6.19.11 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/33095ae3bdde5e5c264d7e88a2f3e7703a26c7aa
- https://git.kernel.org/stable/c/e7824ec168d2ac883a213cd1f4d6cc0816002a85
- https://git.kernel.org/stable/c/5e8e06bf8909e79b4acd950cf578cfc2f10bbefa
- https://git.kernel.org/stable/c/de7c0c04ad868f2cee6671b11c0a6d20421af1da
- https://git.kernel.org/stable/c/7475dfad10a05a5bfadebf5f2499bd61b19ed293
- https://git.kernel.org/stable/c/92e47ad03e03dbb5515bdf06444bf6b1e147310d
- https://git.kernel.org/stable/c/71112e62807d1925dc3ae6188b11f8cfc85aec23
- https://git.kernel.org/stable/c/210d36d892de5195e6766c45519dfb1e65f3eb83
ADP enrichment
No English description supplied.