Red Hat Enterprise Linux 6: RHSA-2013:1605-02 Moderate: Glibc Update

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.