The kvm_vm_ioctl_assign_device function in virt/kvm/assigned-dev.c in the KVM subsystem in the Linux kernel before 3.1.10 does not verify permission to access PCI configuration space and BAR resources, which allows host OS users to assign PCI devices and cause a denial of service (host OS crash) via a KVM_ASSIGN_PCI_DEVICE operation.
https://github.com/torvalds/linux/commit/c4e7f9022e506c6635a5037713c37118e23193e4
https://bugzilla.redhat.com/show_bug.cgi?id=756084
http://www.openwall.com/lists/oss-security/2011/11/24/7
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.1.10