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CVE-2016-2549

Published: 24 February 2016

sound/core/hrtimer.c in the Linux kernel before 4.4.1 does not prevent recursive callback access, which allows local users to cause a denial of service (deadlock) via a crafted ioctl call. However, the previous fix is still insufficient: it may still cause a lockup when the ALSA timer instance reprograms itself in its callback. Then it invokes the start function even in snd_timer_interrupt() that is called in hrtimer callback itself, results in a CPU stall. This is no hypothetical problem but actually triggered by syzkaller fuzzer.

From the Ubuntu security team

Dmitry Vyukov discovered that the Advanced Linux Sound Architecture (ALSA) framework's handling of high resolution timers could lead to a deadlock condition. A local attacker could use this to cause a denial of service (system hang).

Priority

Medium

CVSS 3 base score: 6.2

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
Patches:
Introduced by 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Fixed by 2ba1fe7a06d3624f9a7586d672b55f08f7c670f3
linux-armadaxp
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
This package is not directly supported by the Ubuntu Security Team
linux-aws
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-flo
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-gke
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-goldfish
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-grouper
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-hwe
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-hwe-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-linaro-omap
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-linaro-shared
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-linaro-vexpress
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-lts-quantal
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
This package is not directly supported by the Ubuntu Security Team
linux-lts-raring
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-lts-saucy
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-lts-utopic
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-lts-vivid
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-lts-wily
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-lts-xenial
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-maguro
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-mako
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-manta
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-qcm-msm
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-raspi2
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-snapdragon
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)
linux-ti-omap4
Launchpad, Ubuntu, Debian
Upstream
Released (4.5~rc1)