==========================================================================
Ubuntu Security Notice USN-2644-2
June 21, 2015

linux-lts-utopic regression
==========================================================================

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

- Ubuntu 14.04 LTS

Summary:

The system could be made to crash under certain conditions.

Software Description:
- linux-lts-utopic: Linux hardware enablement kernel from Utopic

Details:

The Fix for CVE-2015-1328 introduced a regression into the Linux kernel's
overlayfs file system. The removal of a directory that only exists on the
lower layer results in a kernel panic.

We apologize for the inconvenience.

Original advisory details:

 Philip Pettersson discovered a privilege escalation when using overlayfs
 mounts inside of user namespaces. A local user could exploit this flaw to
 gain administrative privileges on the system.

Update instructions:

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

Ubuntu 14.04 LTS:
  linux-image-3.16.0-41-generic   3.16.0-41.57~14.04.1
  linux-image-3.16.0-41-generic-lpae  3.16.0-41.57~14.04.1
  linux-image-3.16.0-41-lowlatency  3.16.0-41.57~14.04.1
  linux-image-3.16.0-41-powerpc-e500mc  3.16.0-41.57~14.04.1
  linux-image-3.16.0-41-powerpc-smp  3.16.0-41.57~14.04.1
  linux-image-3.16.0-41-powerpc64-emb  3.16.0-41.57~14.04.1
  linux-image-3.16.0-41-powerpc64-smp  3.16.0-41.57~14.04.1

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

References:
  http://www.ubuntu.com/usn/usn-2644-2
  http://www.ubuntu.com/usn/usn-2644-1
  http://bugs.launchpad.net/bugs/1465998

Package Information:
  https://launchpad.net/ubuntu/+source/linux-lts-utopic/3.16.0-41.57~14.04.1