(RHSA-2012:1359) Moderate: libvirt security and bug fix update

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.

A flaw was found in libvirtd’s RPC call handling. An attacker able to
establish a read-only connection to libvirtd could use this flaw to crash
libvirtd by sending an RPC message that has an event as the RPC number, or
an RPC number that falls into a gap in the RPC dispatch table.
(CVE-2012-4423)

This issue was discovered by Wenlong Huang of the Red Hat Virtualization QE
Team.

This update also fixes the following bugs:

• When the host_uuid option was present in the libvirtd.conf file, the
  augeas libvirt lens was unable to parse the file. This bug has been fixed
  and the augeas libvirt lens now parses libvirtd.conf as expected in the
  described scenario. (BZ#858988)

• Disk hot plug is a two-part action: the qemuMonitorAddDrive() call is
  followed by the qemuMonitorAddDevice() call. When the first part succeeded
  but the second one failed, libvirt failed to roll back the first part and
  the device remained in use even though the disk hot plug failed. With this
  update, the rollback for the drive addition is properly performed in the
  described scenario and disk hot plug now works as expected. (BZ#859376)

• When a virtual machine was started with an image chain using block
  devices and a block rebase operation was issued, the operation failed on
  completion in the blockJobAbort() function. This update relabels and
  configures cgroups for the backing files and the rebase operation now
  succeeds. (BZ#860720)

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.