USN-1285-1: Linux kernel vulnerabilities

29 November 2011

linux vulnerabilities

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

  • Ubuntu 11.04

Summary

Several security issues were fixed in the kernel.

Software Description

  • linux - Linux kernel

Details

Andrea Righi discovered a race condition in the KSM memory merging support. If KSM was being used, a local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2183)

Vasily Averin discovered that the NFS Lock Manager (NLM) incorrectly handled unlock requests. A local attacker could exploit this to cause a denial of service. (CVE-2011-2491)

Vasiliy Kulikov discovered that taskstats did not enforce access restrictions. A local attacker could exploit this to read certain information, leading to a loss of privacy. (CVE-2011-2494)

Vasiliy Kulikov discovered that /proc/PID/io did not enforce access restrictions. A local attacker could exploit this to read certain information, leading to a loss of privacy. (CVE-2011-2495)

It was discovered that the wireless stack incorrectly verified SSID lengths. A local attacker could exploit this to cause a denial of service or gain root privileges. (CVE-2011-2517)

Christian Ohm discovered that the perf command looks for configuration files in the current directory. If a privileged user were tricked into running perf in a directory containing a malicious configuration file, an attacker could run arbitrary commands and possibly gain privileges. (CVE-2011-2905)

Vasiliy Kulikov discovered that the Comedi driver did not correctly clear memory. A local attacker could exploit this to read kernel stack memory, leading to a loss of privacy. (CVE-2011-2909)

Update instructions

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

Ubuntu 11.04
linux-image-2.6.38-13-generic - 2.6.38-13.52
linux-image-2.6.38-13-generic-pae - 2.6.38-13.52
linux-image-2.6.38-13-omap - 2.6.38-13.52
linux-image-2.6.38-13-powerpc - 2.6.38-13.52
linux-image-2.6.38-13-powerpc-smp - 2.6.38-13.52
linux-image-2.6.38-13-powerpc64-smp - 2.6.38-13.52
linux-image-2.6.38-13-server - 2.6.38-13.52
linux-image-2.6.38-13-versatile - 2.6.38-13.52
linux-image-2.6.38-13-virtual - 2.6.38-13.52

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