CVE-2022-49957: kcm: fix strp_init() order and cleanup

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-06-17
Weakness: CWE-908

Description

In the Linux kernel, the following vulnerability has been resolved: kcm: fix strp_init() order and cleanup strp_init() is called just a few lines above this csk->sk_user_data check, it also initializes strp->work etc., therefore, it is unnecessary to call strp_done() to cancel the freshly initialized work. And if sk_user_data is already used by KCM, psock->strp should not be touched, particularly strp->work state, so we need to move strp_init() after the csk->sk_user_data check. This also makes a lockdep warning reported by syzbot go away.

Affected products

Linux kernel: from 4.9.84 before 4.10; from 4.9.100 before 4.10; from 4.14.22 before 4.14.293; from 4.14.41 before 4.15; from 4.15.1 before 4.19.258; from 4.20 before 5.4.213 — fixed in 4.10, 4.14.293, 4.15, 4.19.258, 5.10.142, 5.15.66

How to fix

Upgrade to a fixed version: Linux kernel 4.10, 4.14.293, 4.15, 4.19.258. Check the vendor advisory for mitigations.

References

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