util-linux: Local privilege escalation

Background

util-linux is a suite of Linux programs including mount and umount, programs used to mount and unmount filesystems.

Description

Ludwig Nussel discovered that the check_special_mountprog() and check_special_umountprog() functions call setuid() and setgid() in the wrong order and do not check the return values, which can lead to privileges being dropped improperly.

Impact

A local attacker may be able to exploit this vulnerability by using mount helpers such as the mount.nfs program to gain root privileges and run arbitrary commands.

Workaround

There is no known workaround at this time.

Resolution

All util-linux users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=sys-apps/util-linux-2.12r-r8"