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Ubuntu: Security update for Linux kernel

Jon Howell reported a flaw in the Linux kernel’s KVM (Kernel-based virtual machine) subsystem’s handling of the XSAVE CPU feature. On hosts without the XSAVE CPU feature, using qemu userspace, an unprivileged local attacker could exploit this flaw to crash the system. A flaw was discovered in the Linux kernel’s handling of script execution when module loading is enabled. A local attacker could exploit this flaw to cause a leak of kernel stack contents. Florian Weimer discovered that hypervkvpd, which is distributed in the Linux kernel, was not correctly validating source addresses of netlink packets. An untrusted local user can cause a denial of service by causing hypervkvpd to exit.

Updated packages are available from security.ubuntu.com.

==========================================================================
Ubuntu Security Notice USN-1696-1
January 18, 2013

linux vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 12.04 LTS

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

Jon Howell reported a flaw in the Linux kernel's KVM (Kernel-based virtual
machine) subsystem's handling of the XSAVE CPU feature. On hosts without the
XSAVE CPU feature, using qemu userspace, an unprivileged local attacker could
exploit this flaw to crash the system. (CVE-2012-4461)

A flaw was discovered in the Linux kernel's handling of script execution
when module loading is enabled. A local attacker could exploit this flaw to
cause a leak of kernel stack contents. (CVE-2012-4530)

Florian Weimer discovered that hypervkvpd, which is distributed in the
Linux kernel, was not correctly validating source addresses of netlink
packets. An untrusted local user can cause a denial of service by causing
hypervkvpd to exit. (CVE-2012-5532)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 12.04 LTS:
 linux-image-3.2.0-36-generic    3.2.0-36.57
 linux-image-3.2.0-36-generic-pae  3.2.0-36.57
 linux-image-3.2.0-36-highbank   3.2.0-36.57
 linux-image-3.2.0-36-omap       3.2.0-36.57
 linux-image-3.2.0-36-powerpc-smp  3.2.0-36.57
 linux-image-3.2.0-36-powerpc64-smp  3.2.0-36.57
 linux-image-3.2.0-36-virtual    3.2.0-36.57

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-1696-1
 CVE-2012-4461, CVE-2012-4530, CVE-2012-5532

Package Information:
 https://launchpad.net/ubuntu/+source/linux/3.2.0-36.57
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