CVE-2024-53186: ksmbd: fix use-after-free in SMB request handling
First published: Fri Dec 27 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| >=6.6.55<6.6.64 | ||
| >=6.10.14<6.11 | ||
| >=6.11.3<6.11.11 | ||
| >=6.12<6.12.2 |
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Frequently Asked Questions
What is the severity of CVE-2024-53186?
The severity of CVE-2024-53186 has not been explicitly assigned, but it is crucial to address due to its potential impact on system stability.
How do I fix CVE-2024-53186?
To fix CVE-2024-53186, update the Linux kernel to a version later than 6.6.64, 6.10.14, 6.11.3, or 6.12.
Which versions of the Linux kernel are affected by CVE-2024-53186?
CVE-2024-53186 affects Linux kernel versions from 6.6.55 to 6.6.64, 6.10.14 to 6.11, 6.11.3 to 6.11.11, and 6.12 to 6.12.2.
What type of vulnerability is CVE-2024-53186?
CVE-2024-53186 is identified as a use-after-free vulnerability caused by a race condition in SMB request handling.
What components are affected by CVE-2024-53186?
CVE-2024-53186 specifically affects the ksmbd component of the Linux kernel.
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