(RHSA-2015:0016) Moderate: glibc security and bug fix update

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 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)

The CVE-2014-7817 issue was discovered by Tim Waugh of the Red Hat
Developer Experience Team.

This update also fixes the following bugs:

• Previously, when an address lookup using the getaddrinfo() function for
  the AF_UNSPEC value was performed on a defective DNS server, the server in
  some cases responded with a valid response for the A record, but a referral
  response for the AAAA record, which resulted in a lookup failure. A prior
  update was implemented for getaddrinfo() to return the valid response, but
  it contained a typographical error, due to which the lookup could under
  some circumstances still fail. This error has been corrected and
  getaddrinfo() now returns a valid response in the described circumstances.
  (BZ#1172023)

• An error in the dlopen() library function previously caused recursive
  calls to dlopen() to terminate unexpectedly or to abort with a library
  assertion. This error has been fixed and recursive calls to dlopen() no
  longer crash or abort. (BZ#1173469)

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