Scientific Linux Security Update : kvm on SL5.x x86_64
Medium Nessus Plugin ID 60837
SynopsisThe remote Scientific Linux host is missing one or more security updates.
DescriptionIt was found that QEMU-KVM on the host did not validate all pointers provided from a guest system's QXL graphics card driver. A privileged guest user could use this flaw to cause the host to dereference an invalid pointer, causing the guest to crash (denial of service) or, possibly, resulting in the privileged guest user escalating their privileges on the host. (CVE-2010-0431)
A flaw was found in QEMU-KVM, allowing the guest some control over the index used to access the callback array during sub-page MMIO initialization. A privileged guest user could use this flaw to crash the guest (denial of service) or, possibly, escalate their privileges on the host. (CVE-2010-2784)
A NULL pointer dereference flaw was found when the host system had a processor with the Intel VT-x extension enabled. A privileged guest user could use this flaw to trick the host into emulating a certain instruction, which could crash the host (denial of service).
This update also fixes the following bugs :
- running a 'qemu-img' check on a faulty virtual machine image ended with a segmentation fault. With this update, the segmentation fault no longer occurs when running the 'qemu-img' check. (BZ#610342)
- when attempting to transfer a file between two guests that were joined in the same virtual LAN (VLAN), the receiving guest unexpectedly quit. With this update, the transfer completes successfully. (BZ#610343)
- installation of a system was occasionally failing in KVM. This was caused by KVM using wrong permissions for large guest pages. With this update, the installation completes successfully. (BZ#616796)
- previously, the migration process would fail for a virtual machine because the virtual machine could not map all the memory. This was caused by a conflict that was initiated when a virtual machine was initially run and then migrated right away. With this update, the conflict no longer occurs and the migration process no longer fails. (BZ#618205)
- using a thinly provisioned VirtIO disk on iSCSI storage and performing a 'qemu-img' check during an 'e_no_space' event returned cluster errors. With this update, the errors no longer appear. (BZ#618206)
NOTE: The following procedure must be performed before this update will take effect :
1) Stop all KVM guest virtual machines.
2) Either reboot the hypervisor machine or, as the root user, remove (using 'modprobe -r [module]') and reload (using 'modprobe [module]') all of the following modules which are currently running (determined using 'lsmod'): kvm, ksm, kvm-intel or kvm-amd.
3) Restart the KVM guest virtual machines.
SolutionUpdate the affected packages.