Several security issues were fixed in the kernel.
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)
24 November 2011
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
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)
It was discovered that an mmap() call with the MAP_PRIVATE flag on “/dev/zero” was incorrectly handled. A local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2479)
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)
Robert Swiecki discovered that mapping extensions were incorrectly handled. A local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2496)
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)
Yogesh Sharma discovered that CIFS did not correctly handle UNCs that had no prefixpaths. A local attacker with access to a CIFS partition could exploit this to crash the system, leading to a denial of service. (CVE-2011-3363)
The problem can be corrected by updating your system to the following package versions:
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.
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