ALSA timer ioctls have an open race and this may lead to a use-after-free of timer instance object. A simplistic fix is to make each ioctl exclusive. We have already tread_sem for controlling the tread, and extend this as a global mutex to be applied to each ioctl. Upstream patch: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=af368027a49a751d6ff4ee9e3f9961f35bb4fede CVE-ID request and assignment: http://seclists.org/oss-sec/2016/q1/133 http://seclists.org/oss-sec/2016/q1/410
This was fixed in 4.3.5 with commit 7066da22b1eb40e955f9dfe57022816fae53d3cf Author: Takashi Iwai <tiwai> Date: Wed Jan 13 17:48:01 2016 +0100 ALSA: timer: Fix race among timer ioctls commit af368027a49a751d6ff4ee9e3f9961f35bb4fede upstream. and in 4.4.1 with: commit d87622a1662af5782c94b88a613c09de0bde5288 Author: Takashi Iwai <tiwai> Date: Wed Jan 13 17:48:01 2016 +0100 ALSA: timer: Fix race among timer ioctls commit af368027a49a751d6ff4ee9e3f9961f35bb4fede upstream. All Fedora branches are on those or newer. This issue is fixed in Fedora.
Statement: This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and MRG-2. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.