RHSA-2015:0327 - Security Advisory

Topic

Updated glibc packages that fix two security issues and several bugs are
now available for Red Hat Enterprise Linux 7.

Red Hat Product Security 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.

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.

An out-of-bounds read flaw was found in the way glibc's iconv() function
converted certain encoded data to UTF-8. An attacker able to make an
application call the iconv() function with a specially crafted argument
could use this flaw to crash that application. (CVE-2014-6040)

It was found that the files back end of Name Service Switch (NSS) did not
isolate iteration over an entire database from key-based look-up API calls.
An application performing look-ups on a database while iterating over it
could enter an infinite loop, leading to a denial of service.
(CVE-2014-8121)

This update also fixes the following bugs:

• Due to problems with buffer extension and reallocation, the nscd daemon

terminated unexpectedly with a segmentation fault when processing long
netgroup entries. With this update, the handling of long netgroup entries
has been corrected and nscd no longer crashes in the described scenario.
(BZ#1138520)

• If a file opened in append mode was truncated with the ftruncate()

function, a subsequent ftell() call could incorrectly modify the file
offset. This update ensures that ftell() modifies the stream state only
when it is in append mode and the buffer for the stream is not empty.
(BZ#1156331)

• A defect in the C library headers caused builds with older compilers to

generate incorrect code for the btowc() function in the older compatibility C++
standard library. Applications calling btowc() in the compatibility C++ standard
library became unresponsive. With this update, the C library headers have been
corrected, and the compatibility C++ standard library shipped with Red Hat
Enterprise Linux has been rebuilt. Applications that rely on the compatibility
C++ standard library no longer hang when calling btowc(). (BZ#1120490)

• Previously, when using netgroups and the nscd daemon was set up to cache

netgroup information, the sudo utility denied access to valid users. The bug in
nscd has been fixed, and sudo now works in netgroups as
expected. (BZ#1080766)

Users of glibc are advised to upgrade to these updated packages, which fix these
issues.

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 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - 1103874 - Fix memory fencing error in unwind-forcedunwind.c
• BZ - 1124453 - getconf PATH returns non-directory "/bin"
• BZ - 1135841 - CVE-2014-6040 glibc: crash in code page decoding functions (IBM933, IBM935, IBM937, IBM939, IBM1364)
• BZ - 1138520 - nscd segfaults when running sudo with netgroup caching enabled.
• BZ - 1165192 - CVE-2014-8121 glibc: Unexpected closing of nss_files databases after lookups causes denial of service

CVEs

• CVE-2014-6040
• CVE-2014-8121

References

• https://access.redhat.com/security/updates/classification/#moderate