RHSA-2012:0393 - Security Advisory

Topic

Updated glibc packages that fix one security issue and three bugs are now
available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
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.

Description

The glibc packages provide the standard C and standard math libraries used
by multiple programs on the system. Without these libraries, the Linux
system cannot function correctly.

An integer overflow flaw was found in the implementation of the printf
functions family. This could allow an attacker to bypass FORTIFY_SOURCE
protections and execute arbitrary code using a format string flaw in
an application, even though these protections are expected to limit the
impact of such flaws to an application abort. (CVE-2012-0864)

This update also fixes the following bugs:

• Previously, the dynamic loader generated an incorrect ordering for

initialization according to the ELF specification. This could result in
incorrect ordering of DSO constructors and destructors. With this update,
dependency resolution has been fixed. (BZ#783999)

• Previously, locking of the main malloc arena was incorrect in the retry

path. This could result in a deadlock if an sbrk request failed. With this
update, locking of the main arena in the retry path has been fixed. This
issue was exposed by a bug fix provided in the RHSA-2012:0058 update.
(BZ#795328)

• Calling memcpy with overlapping arguments on certain processors would

generate unexpected results. While such code is a clear violation of
ANSI/ISO standards, this update restores prior memcpy behavior. (BZ#799259)

All users of glibc are advised to upgrade to these updated packages, which
contain patches to resolve 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/knowledge/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 i386
• Red Hat Enterprise Linux Server - AUS 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.2 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.2 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 i386
• Red Hat Storage 2.0 x86_64
• Red Hat Gluster Storage Server for On-premise 2.0 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.0 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 794766 - CVE-2012-0864 glibc: FORTIFY_SOURCE format string protection bypass via "nargs" integer overflow
• BZ - 799259 - Change in memcpy behavior for overlapping arguments breaks existing applications

CVEs

• CVE-2012-0864

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://rhn.redhat.com/errata/RHSA-2012-0058.html