5 - RHSA-2013:1605

Problem Description:

Updated glibc packages that fix three security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 6.

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

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 libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the Name Server Caching Daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

Multiple integer overflow flaws, leading to heap-based buffer overflows, were found in glibc's memory allocator functions (pvalloc, valloc, and memalign). If an application used such a function, it could cause the application to crash or, potentially, execute arbitrary code with the privileges of the user running the application. (CVE-2013-4332)

A flaw was found in the regular expression matching routines that process multibyte character input. If an application utilized the glibc regular expression matching mechanism, an attacker could provide specially-crafted input that, when processed, would cause the application to crash. (CVE-2013-0242)

It was found that getaddrinfo() did not limit the amount of stack memory used during name resolution. An attacker able to make an application resolve an attacker-controlled hostname or IP address could possibly cause the application to exhaust all stack memory and crash. (CVE-2013-1914)

Among other changes, this update includes an important fix for the following bug:

* Due to a defect in the initial release of the getaddrinfo() system call in Red Hat enterprise Linux 6.0, AF_INET and AF_INET6 queries resolved from the /etc/hosts file returned queried names as canonical names. This incorrect behavior is, however, still considered to be the expected behavior. As a result of a recent change in getaddrinfo(), AF_INET6 queries started resolving the canonical names correctly. However, this behavior was unexpected by applications that relied on queries resolved from the /etc/hosts file, and these applications could thus fail to operate properly. This update applies a fix ensuring that AF_INET6 queries resolved from /etc/hosts always return the queried name as canonical. Note that DNS lookups are resolved properly and always return the correct canonical names. A proper fix to AF_INET6 queries resolution from /etc/hosts may be applied in future releases; for now, due to a lack of standard, Red Hat suggests the first entry in the /etc/hosts file, that applies for the IP address being resolved, to be considered the canonical entry. (BZ#1022022)

These updated glibc packages also include additional bug fixes and various enhancements. Space precludes documenting all of these changes in this advisory. Users are directed to the Red Hat Enterprise Linux 6.5 Technical Notes, linked to in the References, for information on the most significant of these changes.

All glibc users are advised to upgrade to these updated packages, which contain backported patches to correct these issues and add these enhancements.

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/site/articles/11258

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

552960 - Possible deadlock in pthread_mutex_lock/pthread_cond_wait 848748 - Malformed xdr request causes reading uninitialize memory and can cause huge memory leaks 903754 - Rename glibc release engineering related directory from `fedora' to `releng' 905874 - CVE-2013-0242 glibc: Buffer overrun (DoS) in regexp matcher by processing multibyte characters 929388 - serious CPU time regressions in the glibc math library 947882 - CVE-2013-1914 glibc: Stack (frame) overflow in getaddrinfo() when processing entry mapping to long list of address structures 952422 - sysconf(_SC_NPROCESSORS_ONLN) performance problem 966775 - [RHEL 6.4] BUG glibc causing double-whetstone performance degradation when compared to RHEL 6.3. 1007545 - CVE-2013-4332 glibc: three integer overflows in memory allocator