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oss-security: [oss-security] CVE request - kernel: prevent heap

[oss-security] CVE request - kernel: prevent heap corruption in snd_ctl_new()

From: Eugene Teo <eugene_at_nospam>
Date: Wed Sep 29 2010 - 06:49:52 GMT
To: oss-security@lists.openwall.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); }