ALSA: timer: Don't take register_mutex with copy_from/to_user()
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.5epss 0.1%
exploitation probability
0.1%top 96% of all CVEs
observed exploitation
nono source reports it
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)(®ister_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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products
Linux · Linux