Updated glibc packages that fix two security issues and two bugs are now available for Red Hat Enterprise Linux 6.
The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below.
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.
It was discovered that the glibc dynamic linker/loader did not handle the $ORIGIN dynamic string token set in the LD_AUDIT environment variable securely. A local attacker with write access to a file system containing setuid or setgid binaries could use this flaw to escalate their privileges.
It was discovered that the glibc dynamic linker/loader did not perform sufficient safety checks when loading dynamic shared objects (DSOs) to provide callbacks for its auditing API during the execution of privileged programs. A local attacker could use this flaw to escalate their privileges via a carefully-chosen system DSO library containing unsafe constructors.
Red Hat would like to thank Tavis Ormandy for reporting the CVE-2010-3847
issue, and Ben Hawkes and Tavis Ormandy for reporting the CVE-2010-3856
Previously, the generic implementation of the strstr() and memmem() functions did not handle certain periodic patterns correctly and could find a false positive match. This error has been fixed, and both functions now work as expected.
The "TCB_ALIGNMENT" value has been increased to 32 bytes to prevent applications from crashing during symbol resolution on 64-bit systems with support for Intel AVX vector registers.
All users are advised to upgrade to these updated packages, which contain backported patches to correct these issues.