Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in SMB request handling A race condition exists between SMB request handling in `ksmbd_conn_handler_loop()` and the freeing of `ksmbd_conn` in the workqueue handler `handle_ksmbd_work()`. This leads to a UAF. - KASAN: slab-use-after-free Read in handle_ksmbd_work - KASAN: slab-use-after-free in rtlock_slowlock_locked This race condition arises as follows: - `ksmbd_conn_handler_loop()` waits for `conn->r_count` to reach zero: `wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);` - Meanwhile, `handle_ksmbd_work()` decrements `conn->r_count` using `atomic_dec_return(&conn->r_count)`, and if it reaches zero, calls `ksmbd_conn_free()`, which frees `conn`. - However, after `handle_ksmbd_work()` decrements `conn->r_count`, it may still access `conn->r_count_q` in the following line: `waitqueue_active(&conn->r_count_q)` or `wake_up(&conn->r_count_q)` This results in a UAF, as `conn` has already been freed. The discovery of this UAF can be referenced in the following PR for syzkaller's support for SMB requests.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 18f06bacc197d4ac9b518ad1c69999bc3d83e7aa before a96f9eb7add30ba0fafcfe7b7aca090978196800; affected e9dac92f4482a382e8c0fe1bc243da5fc3526b0c before f20b77f7897e6aab9ce5527e6016ad2be5d70a33; affected ee426bfb9d09b29987369b897fe9b6485ac2be27 before 96261adb998a3b513468b6ce17dbec76be5507d4; affected ee426bfb9d09b29987369b897fe9b6485ac2be27 before 9a8c5d89d327ff58e9b2517f8a6afb4181d32c6e; affected 9fd3cde4628bcd3549ab95061f2bab74d2ed4f3b; affected 6.6.55 before 6.6.64; affected 6.11.3 before 6.11.11; affected 6.10.14 before 6.11 |
| Linux / Linux | affected 6.12; unaffected 0 before 6.12; unaffected 6.6.64 through 6.6.*; unaffected 6.11.11 through 6.11.*; unaffected 6.12.2 through 6.12.*; unaffected 6.13 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/a96f9eb7add30ba0fafcfe7b7aca090978196800
- https://git.kernel.org/stable/c/f20b77f7897e6aab9ce5527e6016ad2be5d70a33
- https://git.kernel.org/stable/c/96261adb998a3b513468b6ce17dbec76be5507d4
- https://git.kernel.org/stable/c/9a8c5d89d327ff58e9b2517f8a6afb4181d32c6e
ADP enrichment
No English description supplied.
No references supplied.