Topic

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

Red Hat Product Security has rated this update as having Important security
impact. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available from the CVE link in the
References section.

Description

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems.

A flaw was found in the way QEMU's AMD PCnet Ethernet emulation handled
multi-TMD packets with a length above 4096 bytes. A privileged guest user
in a guest with an AMD PCNet ethernet card enabled could potentially use
this flaw to execute arbitrary code on the host with the privileges of the
hosting QEMU process. (CVE-2015-3209)

Red Hat would like to thank Matt Tait of Google's Project Zero security
team for reporting this issue.

All kvm users are advised to upgrade to these updated packages, which
contain a backported patch to correct this issue. 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.

For details on how to apply this update, refer to:

https://access.redhat.com/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 - 1225882 - CVE-2015-3209 qemu: pcnet: multi-tmd buffer overflow in the tx path

CVEs

• CVE-2015-3209

References

• https://access.redhat.com/security/updates/classification/#important