USN-2640-2: Linux kernel regression

21 June 2015

linux regression

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

  • Ubuntu 12.04 LTS

Summary

The system could be made to crash under certain conditions.

Software Description

  • linux - Linux kernel

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 12.04 LTS
linux-image-3.2.0-86-generic - 3.2.0-86.124
linux-image-3.2.0-86-generic-pae - 3.2.0-86.124
linux-image-3.2.0-86-highbank - 3.2.0-86.124
linux-image-3.2.0-86-omap - 3.2.0-86.124
linux-image-3.2.0-86-powerpc-smp - 3.2.0-86.124
linux-image-3.2.0-86-powerpc64-smp - 3.2.0-86.124
linux-image-3.2.0-86-virtual - 3.2.0-86.124

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References