[USN-1285-1] Linux kernel vulnerabilities

[John Johansen]

==========================================================================
Ubuntu Security Notice USN-1285-1
November 29, 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

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:
  http://www.ubuntu.com/usn/usn-1285-1
  CVE-2011-2183, CVE-2011-2491, CVE-2011-2494, CVE-2011-2495,
  CVE-2011-2517, CVE-2011-2905, CVE-2011-2909

Package Information:
  https://launchpad.net/ubuntu/+source/linux/2.6.38-13.52


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