eglibc, glibc regression

USN-3239-1 fixed vulnerabilities in the GNU C Library. Unfortunately,
the fix for CVE-2015-5180 introduced an internal ABI change within
the resolver library. This update reverts the change. We apologize
for the inconvenience.

Please note that long-running services that were restarted to compensate
for the USN-3239-1 update may need to be restarted again.

Original advisory details:

It was discovered that the GNU C Library incorrectly handled the
strxfrm() function. An attacker could use this issue to cause a denial
of service or possibly execute arbitrary code. This issue only affected
Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2015-8982)

It was discovered that an integer overflow existed in the
_IO_wstr_overflow() function of the GNU C Library. An attacker could
use this to cause a denial of service or possibly execute arbitrary
code. This issue only affected Ubuntu 12.04 LTS and Ubuntu 14.04
LTS. (CVE-2015-8983)

It was discovered that the fnmatch() function in the GNU C Library
did not properly handle certain malformed patterns. An attacker could
use this to cause a denial of service. This issue only affected Ubuntu
12.04 LTS and Ubuntu 14.04 LTS. (CVE-2015-8984)

Alexander Cherepanov discovered a stack-based buffer overflow in the
glob implementation of the GNU C Library. An attacker could use this
to specially craft a directory layout and cause a denial of service.
(CVE-2016-1234)

Florian Weimer discovered a NULL pointer dereference in the DNS
resolver of the GNU C Library. An attacker could use this to cause
a denial of service. (CVE-2015-5180)

Michael Petlan discovered an unbounded stack allocation in the
getaddrinfo() function of the GNU C Library. An attacker could use
this to cause a denial of service. (CVE-2016-3706)

Aldy Hernandez discovered an unbounded stack allocation in the sunrpc
implementation in the GNU C Library. An attacker could use this to
cause a denial of service. (CVE-2016-4429)

Tim Ruehsen discovered that the getaddrinfo() implementation in the
GNU C Library did not properly track memory allocations. An attacker
could use this to cause a denial of service. This issue only affected
Ubuntu 16.04 LTS. (CVE-2016-5417)

Andreas Schwab discovered that the GNU C Library on ARM 32-bit
platforms did not properly set up execution contexts. An attacker
could use this to cause a denial of service. (CVE-2016-6323)