RHSA-2017:0350 - 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):

• Quick emulator (QEMU) built with the Cirrus CLGD 54xx VGA emulator support is vulnerable to an out-of-bounds access issue. It could occur while copying VGA data via bitblt copy in backward mode. A privileged user inside a guest could use this flaw to crash the QEMU process resulting in DoS or potentially execute arbitrary code on the host with privileges of QEMU process on the host. (CVE-2017-2615)
• Quick emulator (QEMU) built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to an out-of-bounds access issue. The issue could occur while copying VGA data in cirrus_bitblt_cputovideo. A privileged user inside guest could use this flaw to crash the QEMU process OR potentially execute arbitrary code on host with privileges of the QEMU process. (CVE-2017-2620)
• An out-of-bounds read-access flaw was found in the QEMU emulator built with IP checksum routines. The flaw could occur when computing a TCP/UDP packet's checksum, because a QEMU function used the packet's payload length without checking against the data buffer's size. A user inside a guest could use this flaw to crash the QEMU process (denial of service). (CVE-2016-2857)

Red Hat would like to thank Wjjzhang (Tencent.com Inc.) and Li Qiang (360.cn Inc.) for reporting CVE-2017-2615 and Ling Liu (Qihoo 360 Inc.) for reporting CVE-2016-2857.

Bug Fix(es):

• Prior to this update, after migrating a guest virtual machine on the little-endian variant of IBM Power Systems and resetting the guest, the guest boot process failed with a "tcmalloc: large alloc" error message. This update fixes the bug, and the described problem no longer occurs. (BZ#1420456)
• The qemu-kvm-rhev package depends on the usbredir and libcacard packages. However, on the little-endian variant of IBM Power Systems, smartcard use is not supported and usbredir and libcacard are thus only available in the Optional channel. As a consequence, qemu-kvm-rhev was previously not installable on these systems if the Optional channel was not available for the user. This update removes usbredir and libcacard as dependencies of qemu-kvm-rhev on little-endian IBM Power Systems, and qemu-kvm-rhev can now be installed as expected in the described scenario. (BZ#1420428)

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 - 1296567 - CVE-2016-2857 Qemu: net: out of bounds read in net_checksum_calculate()
• BZ - 1418200 - CVE-2017-2615 Qemu: display: cirrus: oob access while doing bitblt copy backward mode
• BZ - 1420428 - Remove dependencies required by spice on ppc64le
• BZ - 1420456 - [ppc64le]reset vm when do migration, HMP in src host promp "tcmalloc: large alloc 1073872896 bytes..."
• BZ - 1420484 - CVE-2017-2620 Qemu: display: cirrus: potential arbitrary code execution via cirrus_bitblt_cputovideo

CVEs

• CVE-2016-2857
• CVE-2017-2615
• CVE-2017-2620

References

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