===========================================================================
Ubuntu Security Notice USN-3239-2
March 21, 2017

eglibc, glibc regression
===========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

USN-3239-1 introduced a regression in the GNU C Library.

Software Description:
- glibc: GNU C Library
- eglibc: GNU C Library

Details:

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)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 LTS:
  libc6                           2.23-0ubuntu7

Ubuntu 14.04 LTS:
  libc6                           2.19-0ubuntu6.11

Ubuntu 12.04 LTS:
  libc6                           2.15-0ubuntu10.17

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://www.ubuntu.com/usn/usn-3239-2
  https://www.ubuntu.com/usn/usn-3239-1
  https://bugs.launchpad.net/bugs/1674532

Package Information:
  https://launchpad.net/ubuntu/+source/glibc/2.23-0ubuntu7
  https://launchpad.net/ubuntu/+source/eglibc/2.19-0ubuntu6.11
  https://launchpad.net/ubuntu/+source/eglibc/2.15-0ubuntu10.17