USN-1696-1: Linux kernel vulnerabilities

Ubuntu Security Notice USN-1696-1

17th January, 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 feature. On hosts, using qemu
userspace, without the XSAVE feature 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 version:

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

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.

References

CVE-2012-4461, CVE-2012-4530, CVE-2012-5532