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.
An out-of-bounds read flaw was found in the way libvirt's qemuDomainGetBlockIoTune() function looked up the disk index in a non-persistent (live) disk configuration while a persistent disk configuration was being indexed. A remote attacker able to establish a read-only connection to libvirtd could use this flaw to crash libvirtd or, potentially, leak memory from the libvirtd process. (CVE-2014-3633)
A denial of service flaw was found in the way libvirt's virConnectListAllDomains() function computed the number of used domains. A remote attacker able to establish a read-only connection to libvirtd could use this flaw to make any domain operations within libvirt unresponsive. (CVE-2014-3657)
It was found that when the VIR_DOMAIN_XML_MIGRATABLE flag was used, the QEMU driver implementation of the virDomainGetXMLDesc() function could bypass the restrictions of the VIR_DOMAIN_XML_SECURE flag. A remote attacker able to establish a read-only connection to libvirtd could use this flaw to leak certain limited information from the domain XML data. (CVE-2014-7823)
The CVE-2014-3633 issue was discovered by Luyao Huang of Red Hat.
This update also fixes the following bug:
When dumping migratable XML configuration of a domain, libvirt removes some automatically added devices for compatibility with older libvirt releases. If such XML is passed to libvirt as a domain XML that should be used during migration, libvirt checks this XML for compatibility with the internally stored configuration of the domain. However, prior to this update, these checks failed because of devices that were missing (the same devices libvirt removed). As a consequence, migration with user-supplied migratable XML failed. Since this feature is used by OpenStack, migrating QEMU/KVM domains with OpenStack always failed. With this update, before checking domain configurations for compatibility, libvirt transforms both user-supplied and internal configuration into a migratable form (automatically added devices are removed) and checks those instead. Thus, no matter whether the user-supplied configuration was generated as migratable or not, libvirt does not err about missing devices, and migration succeeds as expected. (BZ#1155564)
All libvirt users 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.