In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix race condition between session lookup and expire

Thread A + Thread B
ksmbd_session_lookup | smb2_sess_setup
sess = xa_load |
|
| xa_erase(&conn->sessions, sess->id);
|
| ksmbd_session_destroy(sess) --> kfree(sess)
|
// UAF! |
sess->last_active = jiffies |
+

This patch add rwsem to fix race condition between ksmbd_session_lookup
and ksmbd_expire_session.

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-52480
• https://git.kernel.org/stable/c/18ced78b0ebccc2d16f426143dc56ab3aad666be
• https://git.kernel.org/stable/c/53ff5cf89142b978b1a5ca8dc4d4425e6a09745f
• https://git.kernel.org/stable/c/a2ca5fd3dbcc665e1169044fa0c9e3eba779202b
• https://git.kernel.org/stable/c/c77fd3e25a51ac92b0f1b347a96eff6a0b4f066f