7.4 - RHSA-2012:0051

Problem Description:

Updated kvm packages that fix two security issues are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

RHEL Desktop Multi OS (v. 5 client) - x86_64 RHEL Virtualization (v. 5 server) - x86_64

3. Description:

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built for the standard Red Hat Enterprise Linux kernel.

A heap overflow flaw was found in the way QEMU-KVM emulated the e1000 network interface card. A privileged guest user in a virtual machine whose network interface is configured to use the e1000 emulated driver could use this flaw to crash the host or, possibly, escalate their privileges on the host. (CVE-2012-0029)

A flaw was found in the way the KVM subsystem of a Linux kernel handled PIT (Programmable Interval Timer) IRQs (interrupt requests) when there was no virtual interrupt controller set up. A malicious user in the kvm group on the host could force this situation to occur, resulting in the host crashing. (CVE-2011-4622)

Red Hat would like to thank Nicolae Mogoreanu for reporting CVE-2012-0029.

All KVM users should upgrade to these updated packages, which contain backported patches to correct these issues. Note: The procedure in the Solution section must be performed before this update will take effect.

4. Solution:

Before applying this update, make sure all previously-released errata relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at https://access.redhat.com/kb/docs/DOC-11259

The following procedure must be performed before this update will take effect:

1) Stop all KVM guest virtual machines.

2) Either reboot the hypervisor machine or, as the root user, remove (using "modprobe -r [module]") and reload (using "modprobe [module]") all of the following modules which are currently running (determined using "lsmod"): kvm, ksm, kvm-intel or kvm-amd.

3) Restart the KVM guest virtual machines.

5. Bugs fixed (http://bugzilla.redhat.com/):

769721 - CVE-2011-4622 kernel: kvm: pit timer with no irqchip crashes the system 772075 - CVE-2012-0029 qemu-kvm: e1000: process_tx_desc legacy mode packets heap overflow