Synopsis

Important: kvm security update

Type/Severity

Security Advisory: Important

Topic

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.

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 divide-by-zero flaw was found in the apic_get_tmcct() function in KVM's
Local Advanced Programmable Interrupt Controller (LAPIC) implementation.
A privileged guest user could use this flaw to crash the host.
(CVE-2013-6367)

A memory corruption flaw was discovered in the way KVM handled virtual APIC
accesses that crossed a page boundary. A local, unprivileged user could use
this flaw to crash the system or, potentially, escalate their privileges on
the system. (CVE-2013-6368)

Red Hat would like to thank Andrew Honig of Google for reporting these
issues.

All kvm users are advised to 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.

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/site/articles/11258

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.

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Workstation 5 x86_64

Fixes

• BZ - 1032207 - CVE-2013-6367 kvm: division by zero in apic_get_tmcct()
• BZ - 1032210 - CVE-2013-6368 kvm: cross page vapic_addr access

CVEs

• CVE-2013-6367
• CVE-2013-6368

References