RHSA-2017:0454 - Security Advisory

Topic

An update for kvm is now available for Red Hat Enterprise Linux 5.

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 (for Kernel-based Virtual Machine) is a full virtualization solution for
Linux on x86 hardware. Using KVM, one can run multiple virtual machines running
unmodified Linux or Windows images. Each virtual machine has private virtualized
hardware: a network card, disk, graphics adapter, etc.

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)

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

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

Note: The procedure in the Solution section must be performed before this update
will take effect.

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Workstation 5 x86_64

Fixes

• BZ - 1418200 - CVE-2017-2615 Qemu: display: cirrus: oob access while doing bitblt copy backward mode
• BZ - 1420484 - CVE-2017-2620 Qemu: display: cirrus: potential arbitrary code execution via cirrus_bitblt_cputovideo

CVEs

• CVE-2017-2615
• CVE-2017-2620

References

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