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 remotely managing virtualized systems.
An integer overflow flaw was found in libvirtd's RPC call handling. An attacker able to establish read-only connections to libvirtd could trigger this flaw by calling virDomainGetVcpus() with specially-crafted parameters, causing libvirtd to crash. (CVE-2011-2511)
This update also fixes the following bugs:
Previously, when the "virsh vol-create-from" command was run on an LVM (Logical Volume Manager) storage pool, performance of the command was very low and the operation consumed an excessive amount of time. This bug has been fixed in the virStorageVolCreateXMLFrom() function, and the performance problem of the command no longer occurs.
Due to a regression, libvirt used undocumented command line options, instead of the recommended ones. Consequently, the qemu-img utility used an invalid argument while creating an encrypted volume, and the process eventually failed. With this update, the bug in the backing format of the storage back end has been fixed, and encrypted volumes can now be created as expected. (BZ#726617)
Due to a bug in the qemuAuditDisk() function, hot unplug failures were never audited, and a hot unplug success was audited as a failure. This bug has been fixed, and auditing of disk hot unplug operations now works as expected. (BZ#728516)
Previously, when a debug process was being activated, the act of preparing a debug message ended up with dereferencing a UUID (universally unique identifier) prior to the NULL argument check. Consequently, an API running the debug process sometimes terminated with a segmentation fault. With this update, a patch has been provided to address this issue, and the crashes no longer occur in the described scenario. (BZ#728546)
The libvirt library uses the "boot=on" option to mark which disk is bootable but it only uses that option if Qemu advertises its support. The qemu-kvm utility in Red Hat Enterprise Linux 6.1 removed support for that option and libvirt could not use it. As a consequence, when an IDE disk was added as the second storage with a virtio disk being set up as the first one by default, the operating system tried to boot from the IDE disk rather than the virtio disk and either failed to boot with the "No bootable disk" error message returned, or the system booted whatever operating system was on the IDE disk. With this update, the boot configuration is translated into bootindex, which provides control over which device is used for booting a guest operating system, thus fixing this bug.
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 must be restarted ("service libvirtd restart") for this update to take effect.