(RHSA-2012:0393) Moderate: glibc security and bug fix update

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.