USN-2840-1: Linux kernel vulnerabilities

17 December 2015

linux vulnerabilities

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

  • Ubuntu 12.04 LTS

Summary

Several security issues were fixed in the kernel.

Software Description

  • linux - Linux kernel

Details

Dmitry Vyukov discovered that the Linux kernel’s keyring handler attempted to garbage collect incompletely instantiated keys. A local unprivileged attacker could use this to cause a denial of service (system crash). (CVE-2015-7872)

Jan Beulich discovered that the KVM svm hypervisor implementation in the Linux kernel did not properly catch Debug exceptions on AMD processors. An attacker in a guest virtual machine could use this to cause a denial of service (system crash) in the host OS. (CVE-2015-8104)

Update instructions

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

Ubuntu 12.04 LTS
linux-image-3.2.0-96-generic - 3.2.0-96.136
linux-image-3.2.0-96-generic-pae - 3.2.0-96.136
linux-image-3.2.0-96-highbank - 3.2.0-96.136
linux-image-3.2.0-96-omap - 3.2.0-96.136
linux-image-3.2.0-96-powerpc-smp - 3.2.0-96.136
linux-image-3.2.0-96-powerpc64-smp - 3.2.0-96.136
linux-image-3.2.0-96-virtual - 3.2.0-96.136

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.

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. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.

References