libvirt security update

CentOS Errata and Security Advisory CESA-2013:0831

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 libvirtd leaked file descriptors when listing all volumes
for a particular pool. A remote attacker able to establish a read-only
connection to libvirtd could use this flaw to cause libvirtd to consume all
available file descriptors, preventing other users from using libvirtd
services (such as starting a new guest) until libvirtd is restarted.
(CVE-2013-1962)

Red Hat would like to thank Edoardo Comar of IBM for reporting this issue.

This update also fixes the following bugs:

• Previously, libvirt made control group (cgroup) requests on files that
  it should not have. With older kernels, such nonsensical cgroup requests
  were ignored; however, newer kernels are stricter, resulting in libvirt
  logging spurious warnings and failures to the libvirtd and audit logs. The
  audit log failures displayed by the ausearch tool were similar to the
  following:

root [date] - failed cgroup allow path rw /dev/kqemu

With this update, libvirt no longer attempts the nonsensical cgroup
actions, leaving only valid attempts in the libvirtd and audit logs (making
it easier to search for real cases of failure). (BZ#958837)

• Previously, libvirt used the wrong variable when constructing audit
  messages. This led to invalid audit messages, causing ausearch to format
  certain entries as having “path=(null)” instead of the correct path. This
  could prevent ausearch from locating events related to cgroup device ACL
  modifications for guests managed by libvirt. With this update, the audit
  messages are generated correctly, preventing loss of audit coverage.
  (BZ#958839)

All users of libvirt 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.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2013-May/081894.html

Affected packages:
libvirt
libvirt-client
libvirt-devel
libvirt-lock-sanlock
libvirt-python

Upstream details at:
https://access.redhat.com/errata/RHSA-2013:0831