libvirt: multiple vulnerabilities

From the Red Hat bugzilla: It was found that libvirt did not honour the user defined main disk format in guest XML when looking up disk backing stores in the security drivers. This could be possibly exploited by privileged guest user to access arbitrary files on the host. (CVE-2010-2237)

From the Red Hat bugzilla: It was found that libvirt did not extract the defined disk backing store format when recursing into disk image backing stores in the security drivers. This could be possibly exploited by privileged guest user to access arbitrary files on the host. (CVE-2010-2238)

From the Red Hat bugzilla: It was found that libvirt did not explicitly set the user defined backing store format when creating new image. This results in images being created with an potentially insecure configuration, preventing applications from opening backing stores without resorting to probing. A privileged guest user could use this flaw to access arbitrary files on the host. (CVE-2010-2239)