7.5 - RHSA-2014:1075

Problem Description:

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

Red Hat Product Security 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.

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)

Red Hat would like to thank NSA for reporting these issues.

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. (BZ#1109715)

* 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. (BZ#1123271)

* 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. (BZ#1125131)

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/articles/11258

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

1097216 - CVE-2014-0222 Qemu: qcow1: validate L2 table size to avoid integer overflows 1097222 - CVE-2014-0223 Qemu: qcow1: validate image size to avoid out-of-bounds memory access 1109715 - live incremental migration of vm with common shared base, size(disk) > size(base) transfers unallocated sectors, explodes disk on dest 1123271 - Enable ioenventfd for virtio-scsi-pci