6.9 - RHSA-2011:0261

Problem Description:

Updated bash packages that fix one security issue and several bugs are now available for Red Hat Enterprise Linux 4.

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 in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux AS version 4 - i386, ia64, ppc, s390, s390x, x86_64 Red Hat Enterprise Linux Desktop version 4 - i386, x86_64 Red Hat Enterprise Linux ES version 4 - i386, ia64, x86_64 Red Hat Enterprise Linux WS version 4 - i386, ia64, x86_64

3. Description:

Bash (Bourne-again shell) is the default shell for Red Hat Enterprise Linux.

It was found that certain scripts bundled with the Bash documentation created temporary files in an insecure way. A malicious, local user could use this flaw to conduct a symbolic link attack, allowing them to overwrite the contents of arbitrary files accessible to the victim running the scripts. (CVE-2008-5374)

This update also fixes the following bugs:

* If a child process's PID was the same as the PID of a previously ended child process, Bash did not wait for that child process. In some cases this caused "Resource temporarily unavailable" errors. With this update, Bash recycles PIDs and waits for processes with recycled PIDs. (BZ#521134)

* Bash's built-in "read" command had a memory leak when "read" failed due to no input (pipe for stdin). With this update, the memory is correctly freed. (BZ#537029)

* Bash did not correctly check for a valid multi-byte string when setting the IFS value, causing Bash to crash. With this update, Bash checks the multi-byte string and no longer crashes. (BZ#539536)

* Bash incorrectly set locale settings when using the built-in "export" command and setting the locale on the same line (for example, with "LC_ALL=C export LC_ALL"). With this update, Bash correctly sets locale settings. (BZ#539538)

All bash users should upgrade to these updated packages, which contain backported patches to correct these issues.

4. 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 http://kbase.redhat.com/faq/docs/DOC-11259

5. Bugs fixed (http://bugzilla.redhat.com/):

475474 - CVE-2008-5374 bash: Insecure temporary file use in aliasconv.sh, aliasconv.bash, cshtobash (symlink attack) 521134 - Bash doesn't wait for backgrounded process if its PID is recycled