cpio: Directory traversal vulnerability

Background

cpio is a file archival tool which can also read and write tar files.

Description

A vulnerability has been found in cpio that can potentially allow a cpio archive to extract its files to an arbitrary directory of the creator’s choice.

Impact

An attacker could create a malicious cpio archive which would create files in arbitrary locations on the victim’s system. This issue could also be used in conjunction with a previous race condition vulnerability (CAN-2005-1111) to change permissions on files owned by the victim.

Workaround

There is no known workaround at this time.

Resolution

All cpio users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=app-arch/cpio-2.6-r3"