6.8 - RHSA-2012:0393

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, x86_64

3. 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.

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 https://access.redhat.com/knowledge/articles/11258

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

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