RHEL 6 : qemu-kvm (RHSA-2011:0919)

This script is Copyright (C) 2013-2014 Tenable Network Security, Inc.


Synopsis :

The remote Red Hat host is missing one or more security updates.

Description :

Updated qemu-kvm packages that fix two security issues and one bug are
now available for Red Hat Enterprise Linux 6.

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.

KVM (Kernel-based Virtual Machine) is a full virtualization solution
for Linux on AMD64 and Intel 64 systems. qemu-kvm is the user-space
component for running virtual machines using KVM.

It was found that the virtio subsystem in qemu-kvm did not properly
validate virtqueue in and out requests from the guest. A privileged
guest user could use this flaw to trigger a buffer overflow, allowing
them to crash the guest (denial of service) or, possibly, escalate
their privileges on the host. (CVE-2011-2212)

It was found that the virtio_queue_notify() function in qemu-kvm did
not perform sufficient input validation on the value later used as an
index into the array of virtqueues. An unprivileged guest user could
use this flaw to crash the guest (denial of service) or, possibly,
escalate their privileges on the host. (CVE-2011-2512)

Red Hat would like to thank Nelson Elhage for reporting CVE-2011-2212.

This update also fixes the following bug :

* A bug was found in the way vhost (in qemu-kvm) set up mappings with
the host kernel's vhost module. This could result in the host kernel's
vhost module not having a complete view of a guest system's memory, if
that guest had more than 4 GB of memory. Consequently, hot plugging a
vhost-net network device and restarting the guest may have resulted in
that device no longer working. (BZ#701771)

All users of qemu-kvm should upgrade to these updated packages, which
contain backported patches to resolve these issues. After installing
this update, shut down all running virtual machines. Once all virtual
machines have shut down, start them again for this update to take
effect.

See also :

https://www.redhat.com/security/data/cve/CVE-2011-2212.html
https://www.redhat.com/security/data/cve/CVE-2011-2512.html
http://rhn.redhat.com/errata/RHSA-2011-0919.html

Solution :

Update the affected packages.

Risk factor :

High / CVSS Base Score : 7.4
(CVSS2#AV:A/AC:M/Au:S/C:C/I:C/A:C)

Family: Red Hat Local Security Checks

Nessus Plugin ID: 63987 ()

Bugtraq ID:

CVE ID: CVE-2011-2212
CVE-2011-2512