CVE-2025-23134

ALSA: timer: Don't take register_mutex with copy_from/to_user()

State: Published
Severity: 5.5 Medium
Published: Apr 16, 2025
Updated: May 11, 2026
Reserved: Jan 11, 2025

Description

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

ALSA: timer: Don't take register_mutex with copy_from/to_user()

The infamous mmap_lock taken in copy_from/to_user() can be often problematic when it's called inside another mutex, as they might lead to deadlocks.

In the case of ALSA timer code, the bad pattern is with guard(mutex)(&register_mutex) that covers copy_from/to_user() -- which was mistakenly introduced at converting to guard(), and it had been carefully worked around in the past.

This patch fixes those pieces simply by moving copy_from/to_user() out of the register mutex lock again.

Scores

CVSS	Score	Vector	Source
3.1	5.5 Medium	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	CISA-ADP

Weaknesses

CWE-667 Improper Locking

Affected Products

Product	Versions
LinuxLinux	3923de04c81733b30b8ed667569632272fdfed9a to before 15291b561d8cc835a2eea76b394070cf8e072771Affected 3923de04c81733b30b8ed667569632272fdfed9a to before 296f7a9e15aab276db11206cbc1e2ae1215d7862Affected 3923de04c81733b30b8ed667569632272fdfed9a to before b074f47e55df93832bbbca1b524c501e6fea1c0dAffected 3923de04c81733b30b8ed667569632272fdfed9a to before 3424c8f53bc63c87712a7fc22dc13d0cc85fb0d6Affected
LinuxLinux	6.9Affected before 6.9Not affected 6.12.23 through 6.12.Not affected 6.13.11 through 6.13.Not affected 6.14.2 through 6.14.*Not affected 6.15 and laterNot affected

References

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