4.217. xorg-x11-server

Updated xorg-x11-server packages that fix multiple security issues are now available for Red Hat Enterprise Linux 5 and 6.
The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links associated with each description below.
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.

Security Fixes

CVE-2010-4818
Multiple input sanitization flaws were found in the X.Org GLX (OpenGL extension to the X Window System) extension. A malicious, authorized client could use these flaws to crash the X.Org server or, potentially, execute arbitrary code with root privileges.
CVE-2010-4819
An input sanitization flaw was found in the X.Org Render extension. A malicious, authorized client could use this flaw to leak arbitrary memory from the X.Org server process, or possibly crash the X.Org server.
Users of xorg-x11-server should upgrade to these updated packages, which contain backported patches to resolve these issues. All running X.Org server instances must be restarted for this update to take effect.
Updated xorg-x11-server packages that fix one security issue and various bugs are now available for Red Hat Enterprise Linux 5.
The Red Hat Security Response Team has rated this update as having low security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link associated with the description below.
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.

Security Fix

CVE-2011-4028
A flaw was found in the way the X.Org server handled lock files. A local user with access to the system console could use this flaw to determine the existence of a file in a directory not accessible to the user, via a symbolic link attack.
Red Hat would like to thank the researcher with the nickname vladz for reporting this issue.

Bug Fixes

BZ#596899
In rare cases, if the front and back buffer of the miDbePositionWindow() function were not both allocated in video memory, or were both allocated in system memory, the X Window System sometimes terminated unexpectedly. A patch has been provided to address this issue and X no longer crashes in the described scenario.
BZ#676270
Previously, when the miSetShape() function called the miRegionDestroy() function with a NULL region, X terminated unexpectedly if the backing store was enabled. Now, X no longer crashes in the described scenario.
BZ#529717
On certain workstations running in 32-bit mode, the X11 mouse cursor occasionally became stuck near the left edge of the X11 screen. A patch has been provided to address this issue and the mouse cursor no longer becomes stuck in the described scenario.
BZ#559964
On certain workstations with a dual-head graphics adapter using the r500 driver in Zaphod mode, the mouse pointer was confined to one monitor screen and could not move to the other screen. A patch has been provided to address this issue and the mouse cursor works properly across both screens.
BZ#674741
Due to a double free operation, Xvfb (X virtual framebuffer) terminated unexpectedly with a segmentation fault randomly when the last client disconnected, that is when the server reset. This bug has been fixed in the miDCCloseScreen() function and Xvfb no longer crashes.
BZ#454409
Starting the Xephyr server on an AMD64 or Intel 64 architecture with an integrated graphics adapter caused the server to terminate unexpectedly. This bug has been fixed in the code and Xephyr no longer crashes in the described scenario.
BZ#555000
Previously, when a client made a request bigger than 1/4th of the limit advertised in the BigRequestsEnable reply, the X server closed the connection unexpectedly. With this update, the maxBigRequestSize variable has been added to the code to check the size of client requests, thus fixing this bug.
BZ#588346
When an X client running on a big-endian system called the XineramaQueryScreens() function, the X server terminated unexpectedly. This bug has been fixed in the xf86Xinerama module and the X server no longer crashes in the described scenario.
BZ#740497
When installing Red Hat Enterprise Linux 5 on an IBM eServer System p blade server, the installer did not set the correct mode on the built-in KVM (Keyboard-Video-Mouse). Consequently, the graphical installer took a very long time to appear and then was displayed incorrectly. A patch has been provided to address this issue and the graphical installer now works as expected in the described scenario. Note that this fix requires the Red Hat Enterprise Linux 5.8 kernel update.
BZ#649810
Lines longer than 46,340 pixels can be drawn with one of the coordinates being negative. However, for dashed lines, the miPolyBuildPoly() function overflowed the "int" type when setting up edges for a section of a dashed line. Consequently, dashed segments were not drawn at all. An upstream patch has been applied to address this issue and dashed lines are now drawn correctly.
All users of xorg-x11-server are advised to upgrade to these updated packages, which correct these issues. All running X.Org server instances must be restarted for this update to take effect.