(RHSA-2011:1531) Moderate: qemu-kvm security, bug fix, and enhancement update

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. qemu-kvm is the user-space component
for running virtual machines using KVM.

It was found that qemu-kvm did not properly drop supplemental group
privileges when the root user started guests from the command line
(“/usr/libexec/qemu-kvm”) with the “-runas” option. A qemu-kvm process
started this way could use this flaw to gain access to files on the host
that are accessible to the supplementary groups and not accessible to the
primary group. (CVE-2011-2527)

Note: This issue only affected qemu-kvm when it was started directly from
the command line. It did not affect the Red Hat Enterprise Virtualization
platform or applications that start qemu-kvm via libvirt, such as the
Virtual Machine Manager (virt-manager).

This update also fixes several bugs and adds various enhancements.
Documentation for these bug fixes and enhancements will be available
shortly from the Technical Notes document, linked to in the References
section.

All users of qemu-kvm are advised to upgrade to these updated packages,
which contain backported patches to correct these issues and add these
enhancements. After installing this update, shut down all running virtual
machines. Once all virtual machines have shut down, start them again for
this update to take effect.