RHSA-2012:1359 - Security Advisory

Topic

Updated libvirt packages that fix one security issue and multiple 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.

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.

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/knowledge/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 6.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.3 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• 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 6.3 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.3 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.3 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 857133 - CVE-2012-4423 libvirt: null function pointer invocation in virNetServerProgramDispatchCall()
• BZ - 858988 - The libvirt augeas lens can't parse a libvirtd.conf file where host_uuid is present
• BZ - 859376 - after failed hotplug qemu keeps the file descriptor open
• BZ - 860720 - Relabel and configure cgroups for the backing files on VIR_DOMAIN_BLOCK_JOB_ABORT_PIVOT

CVEs

• CVE-2012-4423

References

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