7.5 - RHSA-2014:0743

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64

3. 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.

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/site/articles/11258

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

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