Topic

Updated glibc packages that fix multiple security issues, several bugs, and
add one enhancement 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.

It was discovered that, under certain circumstances, glibc's getaddrinfo()
function would send DNS queries to random file descriptors. An attacker
could potentially use this flaw to send DNS queries to unintended
recipients, resulting in information disclosure or data loss due to the
application encountering corrupted data. (CVE-2013-7423)

A buffer overflow flaw was found in the way glibc's gethostbyname_r() and
other related functions computed the size of a buffer when passed a
misaligned buffer as input. An attacker able to make an application call
any of these functions with a misaligned buffer could use this flaw to
crash the application or, potentially, execute arbitrary code with the
permissions of the user running the application. (CVE-2015-1781)

A heap-based buffer overflow flaw and a stack overflow flaw were found in
glibc's swscanf() function. An attacker able to make an application call
the swscanf() function could use these flaws to crash that application or,
potentially, execute arbitrary code with the permissions of the user
running the application. (CVE-2015-1472, CVE-2015-1473)

An integer overflow flaw, leading to a heap-based buffer overflow, was
found in glibc's _IO_wstr_overflow() function. An attacker able to make an
application call this function could use this flaw to crash that
application or, potentially, execute arbitrary code with the permissions of
the user running the application. (BZ#1195762)

A flaw was found in the way glibc's fnmatch() function processed certain
malformed patterns. An attacker able to make an application call this
function could use this flaw to crash that application. (BZ#1197730)

The CVE-2015-1781 issue was discovered by Arjun Shankar of Red Hat.

These updated glibc packages also include numerous bug fixes and one
enhancement. Space precludes documenting all of these changes in this
advisory. For information on the most significant of these changes, users
are directed to the following article on the Red Hat Customer Portal:

https://access.redhat.com/articles/2050743

All glibc users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues 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 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 7.6 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 7.3 x86_64
• Red Hat Enterprise Linux for Power, little endian 7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.5 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
• 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 Server (for IBM Power LE) - Update Services for SAP Solutions 7.7 ppc64le
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.6 ppc64le
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.4 ppc64le
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.3 ppc64le
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - 1064066 - Test suite failure: test-ldouble
• BZ - 1098042 - getaddrinfo return EAI_NONAME instead of EAI_AGAIN in case the DNS query times out
• BZ - 1144133 - calloc in dl-reloc.c computes size incorrectly
• BZ - 1187109 - CVE-2013-7423 glibc: getaddrinfo() writes DNS queries to random file descriptors under high load
• BZ - 1188235 - CVE-2015-1472 glibc: heap buffer overflow in glibc swscanf
• BZ - 1195762 - glibc: _IO_wstr_overflow integer overflow
• BZ - 1197730 - glibc: potential denial of service in internal_fnmatch()
• BZ - 1199525 - CVE-2015-1781 glibc: buffer overflow in gethostbyname_r() and related functions with misaligned buffer
• BZ - 1207032 - glibc deadlock when printing backtrace from memory allocator
• BZ - 1209105 - CVE-2015-1473 glibc: Stack-overflow in glibc swscanf
• BZ - 1219891 - Missing define for TCP_USER_TIMEOUT in netinet/tcp.h
• BZ - 1225490 - [RFE] Unconditionally enable SDT probes in glibc builds.

CVEs

• CVE-2013-7423
• CVE-2015-1472
• CVE-2015-1473
• CVE-2015-1781

References

• http://www.redhat.com/security/updates/classification/#normal