X.Org X Server: Multiple vulnerabilities

Background

The X Window System is a graphical windowing system based on a client/server model.

Description

vladz reported the following vulnerabilities in the X.Org X server:

• The X.Org X server follows symbolic links when trying to access the lock file for a X display, showing a predictable behavior depending on the file type of the link target (CVE-2011-4028).
• The X.Org X server lock file mechanism allows for a race condition to cause the X server to modify the file permissions of an arbitrary file to 0444 (CVE-2011-4029).

Impact

A local attacker could exploit these vulnerabilities to disclose information by making arbitrary files on a system world-readable or gain information whether a specified file exists on the system and whether it is a file, directory, or a named pipe.

Workaround

There is no known workaround at this time.

Resolution

All X.Org X Server 1.9 users should upgrade to the latest 1.9 version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=x11-base/xorg-server-1.9.5-r1"

All X.Org X Server 1.10 users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=x11-base/xorg-server-1.10.4-r1"