BusyBox provides a single binary that includes versions of a large number of system commands, including a shell. This can be very useful for recovering from certain types of system failures, particularly those involving broken shared libraries.
A buffer underflow flaw was found in the way the uncompress utility of BusyBox expanded certain archive files compressed using Lempel-Ziv compression. If a user were tricked into expanding a specially-crafted archive file with uncompress, it could cause BusyBox to crash or, potentially, execute arbitrary code with the privileges of the user running BusyBox. (CVE-2006-1168)
The BusyBox DHCP client, udhcpc, did not sufficiently sanitize certain options provided in DHCP server replies, such as the client hostname. A malicious DHCP server could send such an option with a specially-crafted value to a DHCP client. If this option's value was saved on the client system, and then later insecurely evaluated by a process that assumes the option is trusted, it could lead to arbitrary code execution with the privileges of that process. Note: udhcpc is not used on Red Hat Enterprise Linux by default, and no DHCP client script is provided with the busybox packages. (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 a core file. This update adds support for recognizing such partitions so the 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 an insensitive search. A patch has been applied to ensure that the combination of 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 result of variable substitution (for example msh -c '$nonexistent_variable'). With this update, msh has been modified to correctly interpret such commands 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 was false, which could cause scripts using the loop to become unresponsive. With this update, msh has been modified to execute and exit empty loops correctly, 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.