RHSA-2014:0743 - Security Advisory

Topic

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

The Red Hat Security Response Team has rated this update as having Moderate
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. The qemu-kvm package provides the
user-space component for running virtual machines using KVM.

Multiple buffer overflow, input validation, and out-of-bounds write flaws
were found in the way the virtio, virtio-net, virtio-scsi, and usb drivers
of QEMU handled state loading after migration. A user able to alter the
savevm data (either on the disk or over the wire during migration) could
use either of these flaws to corrupt QEMU process memory on the
(destination) host, which could potentially result in arbitrary code
execution on the host with the privileges of the QEMU process.
(CVE-2013-4148, CVE-2013-4151, CVE-2013-4535, CVE-2013-4536, CVE-2013-4541,
CVE-2013-4542, CVE-2013-6399, CVE-2014-0182, CVE-2014-3461)

An out-of-bounds memory access flaw was found in the way QEMU's IDE device
driver handled the execution of SMART EXECUTE OFFLINE commands.
A privileged guest user could use this flaw to corrupt QEMU process memory
on the host, which could potentially result in arbitrary code execution on
the host with the privileges of the QEMU process. (CVE-2014-2894)

The CVE-2013-4148, CVE-2013-4151, CVE-2013-4535, CVE-2013-4536,
CVE-2013-4541, CVE-2013-4542, CVE-2013-6399, CVE-2014-0182, and
CVE-2014-3461 issues were discovered by Michael S. Tsirkin of Red Hat,
Anthony Liguori, and Michael Roth.

This update also fixes the following bugs:

• Previously, under certain circumstances, libvirt failed to start guests

which used a non-zero PCI domain and SR-IOV Virtual Functions (VFs), and
returned the following error message:

Can't assign device inside non-zero PCI segment as this KVM module doesn't
support it.

This update fixes this issue and guests using the aforementioned
configuration no longer fail to start. (BZ#1099941)

• Due to an incorrect initialization of the cpus_sts bitmap, which holds

the enablement status of a vCPU, libvirt could fail to start a guest with
an unusual vCPU topology (for example, a guest with three cores and two
sockets). With this update, the initialization of cpus_sts has been
corrected, and libvirt no longer fails to start the aforementioned guests.
(BZ#1100575)

All qemu-kvm users are advised to upgrade to these updated packages, which
contain backported patches to correct 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.

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

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• Red Hat Enterprise Linux Server - AUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386
• Red Hat Enterprise Linux EUS Compute Node 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386

Fixes

• BZ - 1066334 - CVE-2013-4148 qemu: virtio-net: buffer overflow on invalid state load
• BZ - 1066342 - CVE-2013-4151 qemu: virtio: out-of-bounds buffer write on invalid state load
• BZ - 1066361 - CVE-2013-6399 qemu: virtio: buffer overrun on incoming migration
• BZ - 1066382 - CVE-2013-4542 qemu: virtio-scsi: buffer overrun on invalid state load
• BZ - 1066384 - CVE-2013-4541 qemu: usb: insufficient sanity checking of setup_index+setup_len in post_load
• BZ - 1066401 - CVE-2013-4535 CVE-2013-4536 qemu: virtio: insufficient validation of num_sg when mapping
• BZ - 1087971 - CVE-2014-2894 QEMU: out of bounds buffer accesses, guest triggerable via IDE SMART
• BZ - 1088986 - CVE-2014-0182 qemu: virtio: out-of-bounds buffer write on state load with invalid config_len
• BZ - 1096821 - CVE-2014-3461 Qemu: usb: fix up post load checks
• BZ - 1100575 - Some vCPU topologies not accepted by libvirt

CVEs

• CVE-2013-4541
• CVE-2013-4542
• CVE-2014-0182
• CVE-2013-4535
• CVE-2013-4536
• CVE-2013-4151
• CVE-2013-4148
• CVE-2013-6399
• CVE-2014-3461
• CVE-2014-2894

References

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