Description: alsa: use-after-free in /dev/snd/seq
References:
 http://www.openwall.com/lists/oss-security/2017/10/11/3
 https://bugzilla.suse.com/show_bug.cgi?id=1062520
 http://mailman.alsa-project.org/pipermail/alsa-devel/2017-October/126292.html
Notes:
 bwh> The bug appears to have been introduced in 2.6.9 by "ALSA CVS update
 bwh> ... Unlock BKL in ioctl callback to avoid the long preempt-disabling."
 bwh> For !SMP configurations, commit 8009d506a1dd "ALSA: seq: Enable 'use'
 bwh> locking in all configurations" is also needed.
Bugs:
upstream: released (4.14-rc5) [71105998845fb012937332fe2e806d443c09e026]
4.9-upstream-stable: released (4.9.57) [35b84860667ff081eee56b62f3db2a28ca8a3823]
3.16-upstream-stable: released (3.16.50) [853c65fe1db498563bdeea5b7e733441db34d330]
3.2-upstream-stable: released (3.2.95) [c3895a053b2505f9e409e6d6c57dcece714ab486]
sid: released (4.13.4-2) [bugfix/all/ALSA-seq-Fix-use-after-free-at-creating-a-port.patch]
4.9-stretch-security: released (4.9.65-1)
3.16-jessie-security: released (3.16.51-1)
3.2-wheezy-security: released (3.2.96-1)