RHBA-2015:1286 - Bug Fix Advisory

Topic

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

Description

The glibc packages provide the standard C libraries (libc), POSIX thread
libraries (libpthread), standard math libraries (libm), and the name server
cache daemon (nscd) used by multiple programs on the system. Without these
libraries, the Linux system cannot function correctly.

This update fixes these bugs:

• This update of the name service cache daemon (nscd) adds a system of

inotify-based monitoring and stat-based backup monitoring for nscd configuration
files, so that nscd now correctly detects changes to its configuration and
reloads the data. This prevents nscd from returning stale data. (BZ#859965)

• A defect in the library could cause the list of returned netgroups to be

truncated if one of the netgroups in the tree was empty. This error could result
in application crashes or undefined behavior. The library has been fixed to
handle empty netgroups correctly and to return the complete list of requested
netgroups. (BZ#1085312)

• The gethostby* functions generated syslog messages for every unrecognized

record type, even if the resolver options explicitly selected extra data. The
library has been fixed to avoid generating logging messages when the user
explicitly or implicitly requested the data. The number of syslog messages in
DNSSEC-enabled systems related to calls to gethostby* is now reduced.
(BZ#1088301)

• A defect in glibc could cause uninitialized bytes to be sent via a socket

between the nscd client and server. When the application was analyzed using
Valgrind, it reported a problem which could be confusing and misleading. The
library has been fixed to initialize all bytes sent via the socket operation.
Valgrind no longer reports problems with the nscd client. (BZ#1091915)

• A defect in the reinitialization of thread local structures could result in a

too-small thread local storage structure which could lead to unexpected
termination of an application. The thread library has been fixed to reinitialize
the thread local storage structure correctly to prevent applications from
crashing when they reuse thread stacks. (BZ#1116050)

• The times function provided by glibc did not allow users to use a NULL value

for the buffer, and applications passing a NULL could terminate unexpectedly.
The library has been fixed to accept a NULL value for the buffer and return the
expected results from the kernel system call. (BZ#1124204)

• The getaddrinfo(3) function has been improved to return a valid response when

an address lookup using the getaddrinfo(3) function for AF_UNSPEC is performed
on a defective DNS server. (BZ#1138769)

• When using NetApp filers as NFS servers, the rpc.statd service could terminate

unexpectedly. The glibc API segmentation violation in the server Remote
Procedure Call (RPC) code that was causing this crash has been corrected, and
the problem no longer occurs. (BZ#1159167)

• When a system with a large .rhosts file used the rsh shell to connect to a

rlogind server, the authentication could time out. This update adjusts the
ruserok(3) function, so that it first performs user matching in order to avoid
demanding DNS lookups. As a result, rlogind authentication with large .rhosts
files is faster and no longer times out. (BZ#1217186)

In addition, this update adds these enhancements:

• The dlopen(3) function of the library, which is used to load dynamic

libraries, can now be called recursively (a dlopen(3) function can be called
while another dlopen(3) function is already in process). This update prevents
crashes or aborts in applications that need to use the dlopen(3) function in
this way. (BZ#1154563)

• The glibc dynamic loader now supports Intel AVX-512 extensions. This update

allows the dynamic loader to save and restore AVX-512 registers as required,
thus preventing AVX-512-enabled applications from failing because of audit
modules that also use AVX-512. (BZ#1195453)

Users of glibc are advised to upgrade to these updated packages, which fix these
bugs and add these enhancements.

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• 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 Power, big endian 6 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 Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1144019 - CVE-2013-7423 glibc: getaddrinfo() sends DNS queries to random file descriptors [rhel-6.7]
• BZ - 1144132 - calloc in dl-reloc.c computes size incorrectly

CVEs

(none)

References

(none)