USN-2644-2: Linux kernel (Utopic HWE) regression

21 June 2015

linux-lts-utopic regression

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

  • Ubuntu 14.04 LTS


The system could be made to crash under certain conditions.

Software Description

  • linux-lts-utopic - Linux hardware enablement kernel from Utopic


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

To update your system, please follow these instructions:

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