Several security issues were fixed in the kernel.
A bug was discovered in the Linux kernel’s calculation of OOM (Out of memory) scores, that would result in the wrong process being killed. A user could use this to kill the process with the highest OOM score, even if that process belongs to another user or the system. (CVE-2011-4097)
13 February 2012
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
A bug was discovered in the Linux kernel’s calculation of OOM (Out of memory) scores, that would result in the wrong process being killed. A user could use this to kill the process with the highest OOM score, even if that process belongs to another user or the system. (CVE-2011-4097)
A flaw was discovered in the XFS filesystem. If a local user mounts a specially crafted XFS image it could potential execute arbitrary code on the system. (CVE-2012-0038)
Andy Whitcroft discovered a that the Overlayfs filesystem was not doing the extended permission checks needed by cgroups and Linux Security Modules (LSMs). A local user could exploit this to by-pass security policy and access files that should not be accessible. (CVE-2012-0055)
Jüri Aedla discovered that the kernel incorrectly handled /proc/<pid>/mem permissions. A local attacker could exploit this and gain root privileges. (CVE-2012-0056)
A flaw was found in the linux kernels IPv4 IGMP query processing. A remote attacker could exploit this to cause a denial of service. (CVE-2012-0207)
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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