CVE-2014-8989 Information

Description

The Linux kernel through 3.17.4 does not properly restrict dropping of supplemental group memberships in certain namespace scenarios which allows local users to bypass intended file permissions by leveraging a POSIX ACL containing an entry for the group category that is more restrictive than the entry for the other category aka a \negative groups\ issue related to kernel/groups.c kernel/uid16.c and kernel/user_namespace.c.

Reference

http://lists.fedoraproject.org/pipermail/package-announce/2015-January/147864.html http://lists.fedoraproject.org/pipermail/package-announce/2015-January/147973.html http://thread.gmane.org/gmane.linux.man/7385/ http://www.mandriva.com/security/advisories?name=MDVSA-2015:058 http://www.openwall.com/lists/oss-security/2014/11/20/4 http://www.securityfocus.com/bid/71154 http://www.ubuntu.com/usn/USN-2515-1 http://www.ubuntu.com/usn/USN-2516-1 http://www.ubuntu.com/usn/USN-2517-1 http://www.ubuntu.com/usn/USN-2518-1