The Common UNIX Printing System (CUPS) provides a portable printing layer for UNIX operating systems.
A heap-based buffer overflow flaw was found in the Lempel-Ziv-Welch (LZW) decompression algorithm implementation used by the CUPS GIF image format reader. An attacker could create a malicious GIF image file that, when printed, could possibly cause CUPS to crash or, potentially, execute arbitrary code with the privileges of the "lp" user. (CVE-2011-2896)
These updated cups packages also provide fixes for the following bugs:
Previously CUPS was not correctly handling the language setting LANG=en_US.ASCII. As a consequence lpadmin, lpstat and lpinfo binaries were not displaying any output when the LANG=en_US.ASCII environment variable was used. As a result of this update the problem is fixed and the expected output is now displayed. (BZ#681836)
Previously the scheduler did not check for empty values of several configuration directives. As a consequence it was possible for the CUPS daemon (cupsd) to crash when a configuration file contained certain empty values. With this update the problem is fixed and cupsd no longer crashes when reading such a configuration file. (BZ#706673)
Previously when printing to a raw print queue, when using certain printer models, CUPS was incorrectly sending SNMP queries. As a consequence there was a noticeable 4-second delay between queueing the job and the start of printing. With this update the problem is fixed and CUPS no longer tries to collect SNMP supply and status information for raw print queues. (BZ#709896)
Previously when using the BrowsePoll directive it could happen that the CUPS printer polling daemon (cups-polld) began polling before the network interfaces were set up after a system boot. CUPS was then caching the failed hostname lookup. As a consequence no printers were found and the error, "Host name lookup failure", was logged. With this update the code that re-initializes the resolver after failure in cups-polld is fixed and as a result CUPS will obtain the correct network settings to use in printer discovery. (BZ#712430)
The MaxJobs directive controls the maximum number of print jobs that are kept in memory. Previously, once the number of jobs reached the limit, the CUPS system failed to automatically purge the data file associated with the oldest completed job from the system in order to make room for a new print job. This bug has been fixed, and the jobs beyond the set limit are now properly purged. (BZ#735505)
The cups init script (/etc/rc.d/init.d/cups) uses the daemon function (from /etc/rc.d/init.d/functions) to start the cups process, but previously it did not source a configuration file from the /etc/sysconfig/ directory. As a consequence, it was difficult to cleanly set the nice level or cgroup for the cups daemon by setting the NICELEVEL or CGROUP_DAEMON variables. With this update, the init script is fixed. (BZ#744791)
All users of CUPS are advised to upgrade to these updated packages, which contain backported patches to resolve these issues. After installing this update, the cupsd daemon will be restarted automatically.