CVE-2023-52638

/// Technical description

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

can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock

The following 3 locks would race against each other, causing the

deadlock situation in the Syzbot bug report:

- j1939_socks_lock

- active_session_list_lock

- sk_session_queue_lock

A reasonable fix is to change j1939_socks_lock to an rwlock, since in

the rare situations where a write lock is required for the linked list

that j1939_socks_lock is protecting, the code does not attempt to

acquire any more locks. This would break the circular lock dependency,

where, for example, the current thread already locks j1939_socks_lock

and attempts to acquire sk_session_queue_lock, and at the same time,

another thread attempts to acquire j1939_socks_lock while holding

sk_session_queue_lock.

NOTE: This patch along does not fix the unregister_netdevice bug

reported by Syzbot; instead, it solves a deadlock situation to prepare

for one or more further patches to ac

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References