Description
Using the SG_IO IOCTL to issue SCSI requests to partitions or LVM volumes
resulted in the requests being passed to the underlying block device. If a
privileged user only had access to a single partition or LVM volume, they
could use this flaw to bypass those restrictions and gain read and write
access (and be able to issue other SCSI commands) to the entire block
device.
In KVM (Kernel-based Virtual Machine) environments using raw format virtio
disks backed by a partition or LVM volume, a privileged guest user could
bypass intended restrictions and issue read and write requests (and other
SCSI commands) on the host, and possibly access the data of other guests
that reside on the same underlying block device. Partition-based and
LVM-based storage pools are not used by default. Refer to Red Hat Bugzilla
bug 752375 for further details and a mitigation script for users who cannot
apply this update immediately. (CVE-2011-4127, Important)