=========================================================================Ubuntu Security Notice USN-3276-2
May 17, 2017

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

- Ubuntu 17.04
- Ubuntu 16.10
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

USN-3276-1 introduced a regression in su.

Software Description:
- shadow: system login tools

Details:

USN-3276-1 intended to fix a vulnerability in su. The solution introduced
a regression in su signal handling. This update modifies the security fix.
We apologize for the inconvenience.

Original advisory details:

 Sebastian Krahmer discovered integer overflows in shadow utilities.
 A local attacker could possibly cause them to crash or potentially
 gain privileges via crafted input. (CVE-2016-6252)

 Tobias Stöckmann discovered a race condition in su. A local
 attacker could cause su to send SIGKILL to other processes with
 root privileges. (CVE-2017-2616)

Update instructions:

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

Ubuntu 17.04:
  login                           1:4.2-3.2ubuntu1.17.04.2
  passwd                          1:4.2-3.2ubuntu1.17.04.2
  uidmap                          1:4.2-3.2ubuntu1.17.04.2

Ubuntu 16.10:
  login                           1:4.2-3.2ubuntu1.16.10.2
  passwd                          1:4.2-3.2ubuntu1.16.10.2
  uidmap                          1:4.2-3.2ubuntu1.16.10.2

Ubuntu 16.04 LTS:
  login                           1:4.2-3.1ubuntu5.3
  passwd                          1:4.2-3.1ubuntu5.3
  uidmap                          1:4.2-3.1ubuntu5.3

Ubuntu 14.04 LTS:
  login                           1:4.1.5.1-1ubuntu9.5
  passwd                          1:4.1.5.1-1ubuntu9.5
  uidmap                          1:4.1.5.1-1ubuntu9.5

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-3276-2
  https://ubuntu.com/security/notices/USN-3276-1
  https://launchpad.net/bugs/1690820

Package Information:
  https://launchpad.net/ubuntu/+source/shadow/1:4.2-3.2ubuntu1.17.04.2
  https://launchpad.net/ubuntu/+source/shadow/1:4.2-3.2ubuntu1.16.10.2
  https://launchpad.net/ubuntu/+source/shadow/1:4.2-3.1ubuntu5.3
  https://launchpad.net/ubuntu/+source/shadow/1:4.1.5.1-1ubuntu9.5