The snd_ctl_elem_add function in sound/core/control.c in the ALSA control implementation in the Linux kernel before 3.15.2 does not properly maintain the user_ctl_count value, which allows local users to cause a denial of service (integer overflow and limit bypass) by leveraging /dev/snd/controlCX access for a large number of SNDRV_CTL_IOCTL_ELEM_REPLACE ioctl calls.

References

• https://nvd.nist.gov/vuln/detail/CVE-2014-4655
• torvalds/linux@82262a4
• https://bugzilla.redhat.com/show_bug.cgi?id=1113445
• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=82262a46627bebb0febcc26664746c25cef08563
• http://lists.opensuse.org/opensuse-security-announce/2015-04/msg00020.html
• http://rhn.redhat.com/errata/RHSA-2014-1083.html
• http://secunia.com/advisories/59434
• http://secunia.com/advisories/59777
• http://secunia.com/advisories/60545
• http://secunia.com/advisories/60564
• http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.15.2
• http://www.openwall.com/lists/oss-security/2014/06/26/6
• http://www.securityfocus.com/bid/68162
• http://www.securitytracker.com/id/1036763
• http://www.ubuntu.com/usn/USN-2334-1
• http://www.ubuntu.com/usn/USN-2335-1