RHSA-2014:0560 - Security Advisory

Topic

Updated libvirt packages that fix one security issue and three bugs are now
available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having Moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

Description

The libvirt library is a C API for managing and interacting with the
virtualization capabilities of Linux and other operating systems. In
addition, libvirt provides tools for remote management of virtualized
systems.

It was found that libvirt passes the XML_PARSE_NOENT flag when parsing XML
documents using the libxml2 library, in which case all XML entities in the
parsed documents are expanded. A user able to force libvirtd to parse an
XML document with an entity pointing to a special file that blocks on read
access could use this flaw to cause libvirtd to hang indefinitely,
resulting in a denial of service on the system. (CVE-2014-0179)

Red Hat would like to thank the upstream Libvirt project for reporting this
issue. Upstream acknowledges Daniel P. Berrange and Richard Jones as the
original reporters.

This update also fixes the following bugs:

• When hot unplugging a virtual CPU (vCPU), libvirt kept a pointer to

already freed memory if the vCPU was pinned to a host CPU. Consequently,
when reading the CPU pinning information, libvirt terminated unexpectedly
due to an attempt to access this memory. This update ensures that libvirt
releases the pointer to the previously allocated memory when a vCPU is
being hot unplugged, and it no longer crashes in this situation.
(BZ#1091206)

• Previously, libvirt passed an incorrect argument to the "tc" command when

setting quality of service (QoS) on a network interface controller (NIC).
As a consequence, QoS was applied only to IP traffic. With this update,
libvirt constructs the "tc" command correctly so that QoS is applied to all
traffic as expected. (BZ#1096806)

• When using the sanlock daemon for managing access to shared storage,

libvirt expected all QEMU domains to be registered with sanlock. However,
if a QEMU domain was started prior to enabling sanlock, the domain was not
registered with sanlock. Consequently, migration of a virtual machine (VM)
from such a QEMU domain failed with a libvirt error. With this update,
libvirt verifies whether a QEMU domain process is registered with sanlock
before it starts working with the domain, ensuring that migration of
virtual machines works as expected. (BZ#1097227)

All libvirt users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing the
updated packages, libvirtd will be restarted automatically.

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/site/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.5 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.5 ppc64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Virtualization 3 for RHEL 6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 6.5 x86_64
• Red Hat Enterprise Linux Server - AUS 6.5 x86_64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1088290 - CVE-2014-0179 libvirt: unsafe parsing of XML documents allows libvirt DoS and/or arbitrary file read
• BZ - 1091206 - libvirtd crashed after hot-unplug the vcpus which is pinned to host cpus
• BZ - 1096806 - [BUG] Quality of service does just apply to protocol "ip" instead of the device
• BZ - 1097227 - VM migration in RHEV environment failed due to libvirt error "Failed to inquire lock: No such process"

CVEs

• CVE-2014-0179

References

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