Moderate: glibc security and bug fix update

Synopsis

Moderate: glibc security and bug fix update

Type/Severity

Security Advisory: Moderate

Topic

Updated glibc packages that fix one security issue and one bug 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 found that the wordexp() function would perform command substitution
even when the WRDE_NOCMD flag was specified. An attacker able to provide
specially crafted input to an application using the wordexp() function, and
not sanitizing the input correctly, could potentially use this flaw to
execute arbitrary commands with the credentials of the user running that
application. (CVE-2014-7817)

This issue was discovered by Tim Waugh of the Red Hat Developer Experience
Team.

This update also fixes the following bug:

• Prior to this update, if a file stream that was opened in append mode and
  its underlying file descriptor were used at the same time and the file was
  truncated using the ftruncate() function on the file descriptor, a
  subsequent ftell() call on the stream incorrectly modified the file offset
  by seeking to the new end of the file. This update ensures that ftell()
  modifies the state of the file stream only when it is in append mode and
  its buffer is not empty. As a result, the described incorrect changes to
  the file offset no longer occur. (BZ#1170187)
  

All glibc users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues.

Solution

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

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support 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 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 7.6 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 7.6 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 7.6 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 7.4 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 - 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 - 1157689 - CVE-2014-7817 glibc: command execution in wordexp() with WRDE_NOCMD specified
• BZ - 1170187 - Problems when using ftruncate on files opened in append mode

CVEs

• CVE-2014-7817

References

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