CVE-2023-52638: can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-03 · updated 2026-06-17
Weakness: CWE-667

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 actually fix the Syzbot bug, which appears to be a reference counting problem within the j1939 codebase. [mkl: remove unrelated newline change]

Affected products

Linux kernel: before 5.15.149; from 5.16 before 6.1.79; from 6.2 before 6.6.18; from 6.7 before 6.7.6; 6.8-rc1, 6.8-rc2, 6.8-rc3, 6.8-rc4 — fixed in 5.15.149, 6.1.79, 6.6.18, 6.7.6

How to fix

Upgrade to a fixed version: Linux kernel 5.15.149, 6.1.79, 6.6.18, 6.7.6. Check the vendor advisory for mitigations.

References

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