RHSA-2012:0810: Low: busybox security and bug fix update

BusyBox provides a single binary that includes versions of a large numberof system commands, including a shell. This can be very useful forrecovering from certain types of system failures, particularly thoseinvolving broken shared libraries.A buffer underflow flaw was found in the way the uncompress utility ofBusyBox expanded certain archive files compressed using Lempel-Zivcompression. If a user were tricked into expanding a specially-craftedarchive file with uncompress, it could cause BusyBox to crash or,potentially, execute arbitrary code with the privileges of the userrunning BusyBox. (CVE-2006-1168)The BusyBox DHCP client, udhcpc, did not sufficiently sanitize certainoptions provided in DHCP server replies, such as the client hostname. Amalicious DHCP server could send such an option with a specially-craftedvalue to a DHCP client. If this option's value was saved on the clientsystem, and then later insecurely evaluated by a process that assumes theoption is trusted, it could lead to arbitrary code execution with theprivileges of that process. Note: udhcpc is not used on Red Hat EnterpriseLinux by default, and no DHCP client script is provided with the busyboxpackages. (CVE-2011-2716)This update also fixes the following bugs: Prior to this update, the "findfs" command did not recognize Btrfs partitions. As a consequence, an error message could occur when dumping acore file. This update adds support for recognizing such partitions sothe problem no longer occurs. (BZ#751927) If the "grep" command was used with the "-F" and "-i" options at the same time, the "-i" option was ignored. As a consequence, the "grep -iF"command incorrectly performed a case-sensitive search instead of aninsensitive search. A patch has been applied to ensure that the combinationof the "-F" and "-i" options works as expected. (BZ#752134) Prior to this update, the msh shell did not support the "set -o pipefail" command. This update adds support for this command. (BZ#782018) Previously, the msh shell could terminate unexpectedly with a segmentation fault when attempting to execute an empty command as a resultof variable substitution (for example msh -c '$nonexistentvariable').With this update, msh has been modified to correctly interpret suchcommands and no longer crashes in this scenario. (BZ#809092) Previously, the msh shell incorrectly executed empty loops. As a consequence, msh never exited such a loop even if the loop condition wasfalse, which could cause scripts using the loop to become unresponsive.With this update, msh has been modified to execute and exit empty loopscorrectly, so that hangs no longer occur. (BZ#752132)All users of busybox are advised to upgrade to these updated packages,which contain backported patches to fix these issues.