RHSA-2014:0914 - Security Advisory

Topic

Updated libvirt packages that fix one security issue and three bugs are now
available for Red Hat Enterprise Linux 7.

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 file could use this flaw to read
the contents of that file; parsing an XML document with an entity pointing
to a special file that blocks on read access could 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:

• A previous update of the libvirt package introduced an error; a

SIG_SETMASK argument was incorrectly replaced by a SIG_BLOCK argument after
the poll() system call. Consequently, the SIGCHLD signal could be
permanently blocked, which caused signal masks to not return to their
original values and defunct processes to be generated. With this update,
the original signal masks are restored and defunct processes are no longer
generated. (BZ#1112689)

• An attempt to start a domain that did not exist caused network filters to

be locked for read-only access. As a consequence, when trying to gain
read-write access, a deadlock occurred. This update applies a patch to fix
this bug and an attempt to start a non-existent domain no longer causes a
deadlock in the described scenario. (BZ#1112690)

• Previously, the libvirtd daemon was binding only to addresses that were

configured on certain network interfaces. When libvirtd started before the
IPv4 addresses had been configured, libvirtd listened only on the IPv6
addresses. The daemon has been modified to not require an address to be
configured when binding to a wildcard address, such as "0.0.0.0" or "::".
As a result, libvirtd binds to both IPv4 and IPv6 addresses as expected.
(BZ#1112692)

Users of libvirt are advised to upgrade to these updated packages, which
fix these bugs. 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/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 s390x
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64

Fixes

• BZ - 1088290 - CVE-2014-0179 libvirt: unsafe parsing of XML documents allows libvirt DoS and/or arbitrary file read
• BZ - 1112689 - use of tls with libvirt.so can leave zombie processes
• BZ - 1112690 - nwfilter deadlock
• BZ - 1112692 - libvirt binds only to ipv6

CVEs

• CVE-2014-0179
• CVE-2014-5177

References

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