qemu-kvm (SL6)

Synopsis: Moderate: qemu-kvm security and bug fix update
Advisory ID: SLSA-2014:1075-1
Issue Date: 2014-08-19
CVE Numbers: CVE-2014-0222

Two integer overflow flaws were found in the QEMU block driver for QCOW
version 1 disk images. A user able to alter the QEMU disk image files
loaded by a guest could use either of these flaws 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-2014-0222, CVE-2014-0223)

This update also fixes the following bugs:

* In certain scenarios, when performing live incremental migration, the
disk size could be expanded considerably due to the transfer of
unallocated sectors past the end of the base image. With this update, the
bdrv_is_allocated() function has been fixed to no longer return “True” for
unallocated sectors, and the disk size no longer changes after performing
live incremental migration.

* This update enables ioeventfd in virtio-scsi-pci. This allows QEMU to
process I/O requests outside of the vCPU thread, reducing the latency of
submitting requests and improving single task throughput.

* Prior to this update, vendor-specific SCSI commands issued from a KVM
guest did not reach the target device due to QEMU considering such
commands as invalid. This update fixes this bug by properly propagating
vendor-specific SCSI commands to the target device.

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.


– Scientific Linux Development Team