Synopsis

Important: glibc security update

Type/Severity

Security Advisory: Important

Topic

Updated glibc packages that fix multiple security issues are now available
for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

Description

The glibc packages contain the standard C libraries used by multiple
programs on the system. These packages contain the standard C and the
standard math libraries. Without these two libraries, a Linux system cannot
function properly.

The fix for CVE-2010-3847 introduced a regression in the way the dynamic
loader expanded the $ORIGIN dynamic string token specified in the RPATH and
RUNPATH entries in the ELF library header. A local attacker could use this
flaw to escalate their privileges via a setuid or setgid program using
such a library. (CVE-2011-0536)

It was discovered that the glibc addmntent() function did not sanitize its
input properly. A local attacker could possibly use this flaw to inject
malformed lines into /etc/mtab via certain setuid mount helpers, if the
attacker were allowed to mount to an arbitrary directory under their
control. (CVE-2010-0296)

It was discovered that the glibc fnmatch() function did not properly
restrict the use of alloca(). If the function was called on sufficiently
large inputs, it could cause an application using fnmatch() to crash or,
possibly, execute arbitrary code with the privileges of the application.
(CVE-2011-1071)

It was discovered that the locale command did not produce properly escaped
output as required by the POSIX specification. If an attacker were able to
set the locale environment variables in the environment of a script that
performed shell evaluation on the output of the locale command, and that
script were run with different privileges than the attacker's, it could
execute arbitrary code with the privileges of the script. (CVE-2011-1095)

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

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
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 i386
• Red Hat Enterprise Linux Server - AUS 5.6 ia64
• Red Hat Enterprise Linux Server - AUS 5.6 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.6 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.6 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 i386
• Red Hat Enterprise Linux Server - AUS 5.6 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x

Fixes

• BZ - 559579 - CVE-2010-0296 glibc: Improper encoding of names with certain special character in utilities for writing to mtab table
• BZ - 625893 - CVE-2011-1095 glibc: insufficient quoting in the locale command output
• BZ - 667974 - CVE-2011-0536 glibc: CVE-2010-3847 fix causes linker to search CWD when running privileged program with $ORIGIN in R*PATH
• BZ - 681054 - CVE-2011-1071 glibc: fnmatch() alloca()-based memory corruption flaw
• BZ - 682991 - iconv regression

CVEs

• CVE-2011-0536
• CVE-2011-1095
• CVE-2010-0296
• CVE-2011-1071
• CVE-2011-1659
• CVE-2011-1658

References