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[SECURITY] [DSA 2469-1] linux-2.6 security update

Posted on 10 May 2012
Debian Security Advisory

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Debian Security Advisory DSA-2469-1 Dann Frazier
May 10, 2012
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Package : linux-2.6
Vulnerability : privilege escalation/denial of service
Problem type : local
Debian-specific: no
CVE Id(s) : CVE-2011-4086 CVE-2012-0879 CVE-2012-1601 CVE-2012-2123

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:


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.


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.


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.


Steve Grubb reported in 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.


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

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.

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at:

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