RHSA-2013:1620 - Security Advisory

Topic

Updated xorg-x11-server packages that fix one security issue and several
bugs are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having low
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

Description

X.Org is an open source implementation of the X Window System. It provides
the basic low-level functionality that full-fledged graphical user
interfaces are designed upon.

A flaw was found in the way the X.org X11 server registered new hot plugged
devices. If a local user switched to a different session and plugged in a
new device, input from that device could become available in the previous
session, possibly leading to information disclosure. (CVE-2013-1940)

This issue was found by David Airlie and Peter Hutterer of Red Hat.

This update also fixes the following bugs:

• A previous upstream patch modified the Xephyr X server to be resizeable,

however, it did not enable the resize functionality by default. As a
consequence, X sandboxes were not resizeable on Red Hat Enterprise Linux
6.4 and later. This update enables the resize functionality by default so
that X sandboxes can now be resized as expected. (BZ#915202)

• In Red Hat Enterprise Linux 6, the X Security extension (XC-SECURITY)

has been disabled and replaced by X Access Control Extension (XACE).
However, XACE does not yet include functionality that was previously
available in XC-SECURITY. With this update, XC-SECURITY is enabled in the
xorg-x11-server spec file on Red Hat Enterprise Linux 6. (BZ#957298)

• Upstream code changes to extension initialization accidentally disabled

the GLX extension in Xvfb (the X virtual frame buffer), rendering headless
3D applications not functional. An upstream patch to this problem has been
backported so the GLX extension is enabled again, and applications relying
on this extension work as expected. (BZ#969538)

All xorg-x11-server users are advised to upgrade to these updated packages,
which contain backported patches to correct these issues.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/site/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 795858 - X server crashes with segfault at startup when using X font server
• BZ - 915202 - X-sandboxes are not resizeable
• BZ - 950438 - CVE-2013-1940 xorg-x11-server: Information disclosure due enabling events from hot-plug devices despite input from the device being momentarily disabled
• BZ - 1016854 - regression: Xorg -configure stopped working

CVEs

• CVE-2013-1940

References

• https://access.redhat.com/security/updates/classification/#low