4.9 - USN-2911-1

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:

It was discovered that the Linux kernel keyring subsystem contained a race between read and revoke operations. A local attacker could use this to cause a denial of service (system crash).

Update instructions:

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

Ubuntu 12.04 LTS:
linux-image-3.2.0-99-generic 3.2.0-99.139
linux-image-3.2.0-99-generic-pae 3.2.0-99.139
linux-image-3.2.0-99-highbank 3.2.0-99.139
linux-image-3.2.0-99-omap 3.2.0-99.139
linux-image-3.2.0-99-powerpc-smp 3.2.0-99.139
linux-image-3.2.0-99-powerpc64-smp 3.2.0-99.139
linux-image-3.2.0-99-virtual 3.2.0-99.139

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

ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

References:
http://www.ubuntu.com/usn/usn-2911-1
CVE-2015-7550

Package Information:
https://launchpad.net/ubuntu/+source/linux/3.2.0-99.139