CVE request - kernel: prevent heap corruption in snd_ctl_new()

[Eugene Teo <eugene () redhat com>]

Reported by Dan Rosenberg. The snd_ctl_new() function in 
sound/core/control.c allocates space for a snd_kcontrol struct by 
performing arithmetic operations on a user-provided size without 
checking for integer overflow.  If a user provides a large enough size, 
an overflow will occur, the allocated chunk will be too small, and a 
second user-influenced value will be written repeatedly past the bounds 
of this chunk. This code is reachable by unprivileged users who have 
permission to open a /dev/snd/controlC* device (on many distros, this is 
group "audio") via the SNDRV_CTL_IOCTL_ELEM_ADD and 
SNDRV_CTL_IOCTL_ELEM_REPLACE ioctls.

Upstream commit:
http://git.kernel.org/linus/5591bf07225523600450edd9e6ad258bb877b779

Reference:
https://bugzilla.redhat.com/show_bug.cgi?id=638478

Eugene
--
main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i); }