RHBA-2011:1179 - Bug Fix Advisory

Topic

Updated glibc packages that resolve several issues are now available for Red Hat
Enterprise Linux 6.

Description

The glibc packages contain the standard C and the standard math libraries. These
libraries are used by multiple programs on the system, and without these
libraries, the Linux system cannot function properly.

These updated glibc packages provide fixes for the following bugs:

• Under certain circumstances, a threaded process could have been granted

incomplete group membership of the user which was running the process. This was
caused by glibc using its default method for group membership determination,
which led to a situation in which multiple threads interfered with each other
while attempting to retrieve information simultaneously. Due to the nature of
the group membership determination method used, each thread ended up with a
different subset of the entire result set. With this update, the group
membership determination method has been modified to precede this interference.
(BZ#712125)

• When a process corrupted its heap, the malloc() function could have entered a

deadlock situation while building up an error message string. This caused the
process unresponsive. With this update, the code has been modified to use the
mmap() function to allocate memory for the error message. This workaround
ensures that the malloc() deadlock no longer occurs when allocating memory for
an error message when the corrupted process heap is detected, and such a process
is now normally aborted. (BZ#712407)

• Prior to this update, the Name Service Caching Daemon (nscd) did not clear the

host cache effectively when repopulating its values. The code has been modified
to schedule nscd cache pruning more accurately. (BZ#712411)

• Previously, nscd did not take into consideration time-to-live (TTL) parameters

for the DNS records it was caching. With this update, the code has been modified
so that nscd now respects TTL parameters when it answers requests for DNS
records. (BZ#715387)

All users of glibc are advised to upgrade to these updated packages, which
resolve these issues.

Solution

Before applying this update, make sure that all previously-released errata
relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use the Red Hat
Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.1 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 712407 - deadlock in malloc()

CVEs

(none)

References

(none)