Debian Security Advisory

DSA-2469-1 linux-2.6 -- privilege escalation/denial of service

Date Reported:
10 May 2012
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2011-4086, CVE-2012-0879, CVE-2012-1601, CVE-2012-2123, CVE-2012-2133.
More information:

Several vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or privilege escalation. The Common Vulnerabilities and Exposures project identifies the following problems:

  • CVE-2011-4086

    Eric Sandeen reported an issue in the journaling layer for ext4 filesystems (jbd2). Local users can cause buffers to be accessed after they have been torn down, resulting in a denial of service (DoS) due to a system crash.

  • CVE-2012-0879

    Louis Rilling reported two reference counting issues in the CLONE_IO feature of the kernel. Local users can prevent io context structures from being freed, resulting in a denial of service.

  • CVE-2012-1601

    Michael Ellerman reported an issue in the KVM subsystem. Local users could cause a denial of service (NULL pointer dereference) by creating VCPUs before a call to KVM_CREATE_IRQCHIP.

  • CVE-2012-2123

    Steve Grubb reported an issue in fcaps, a filesystem-based capabilities system. Personality flags set using this mechanism, such as the disabling of address space randomization, may persist across suid calls.

  • CVE-2012-2133

    Shachar Raindel discovered a use-after-free bug in the hugepages quota implementation. Local users with permission to use hugepages via the hugetlbfs implementation may be able to cause a denial of service (system crash).

For the stable distribution (squeeze), this problem has been fixed in version 2.6.32-44. Updates are currently only available for the amd64, i386 and sparc ports.

Note: updated linux-2.6 packages will also be made available in the release of Debian 6.0.5, scheduled to take place the weekend of 2012.05.12. This pending update will be version 2.6.32-45, and provides an additional fix for build failures on some architectures. Users for whom this update is not critical, and who may wish to avoid multiple reboots, should consider waiting for the 6.0.5 release before updating, or installing the 2.6.32-45 version ahead of time from proposed-updates.

The following matrix lists additional source packages that were rebuilt for compatibility with or to take advantage of this update:

  Debian 6.0 (squeeze)
user-mode-linux 2.6.32-1um-4+44

We recommend that you upgrade your linux-2.6 and user-mode-linux packages.