RHSA-2017:1431 - Security Advisory

Topic

An update for qemu-kvm-rhev is now available for RHEV 3.X Hypervisor and Agents for RHEL-7 and RHEV 4.X RHEV-H and Agents for RHEL-7.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on a variety of architectures. The qemu-kvm-rhev packages provide the user-space component for running virtual machines that use KVM in environments managed by Red Hat products.

Security Fix(es):

• An out-of-bounds access issue was found in QEMU's Cirrus CLGD 54xx VGA Emulator support. The vulnerability could occur while copying VGA data using bitblt functions (for example, cirrus_bitblt_rop_fwd_transp_). A privileged user inside a guest could use this flaw to crash the QEMU process, resulting in denial of service. (CVE-2017-7718)

Red Hat would like to thank Jiangxin (PSIRT Huawei Inc.) for reporting
CVE-2017-7718.

Bug Fix(es):

• When using post-copy migration with the virtio Random Number Generator (RNG) device, virtio-rng continued generating data while the migration was already in post-copy mode. Consequently, the migration sometimes failed and the error message "Failed to load virtio-rng:virtio" was displayed. The source code has been improved and the problem no longer occurs in the scenario described. (BZ#1450375)

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

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.

Affected Products

• Red Hat Virtualization 4 for RHEL 7 x86_64
• Red Hat Virtualization 3 for RHEL 7 x86_64
• Red Hat Virtualization for IBM Power LE 4 for RHEL 7 ppc64le
• Red Hat Virtualization for IBM Power LE 3 ppc64le

Fixes

• BZ - 1443441 - CVE-2017-7718 Qemu: display: cirrus: OOB read access issue
• BZ - 1450375 - Migration failed with postcopy enabled from rhel7.3.z host to rhel7.4 host "error while loading state for instance 0x0 of device 'pci@800000020000000:05.0/virtio-rng'"

CVEs

• CVE-2017-7718

References

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