Linux netback DoS via malicious guest ring.

ISSUE DESCRIPTION

The Xen netback implementation contains a couple of flaws which can allow a guest to cause a DoS in the backend domain, potentially affecting other domains in the system.
CVE-2013-0216 is a failure to sanity check the ring producer/consumer pointers which can allow a guest to cause netback to loop for an extended period preventing other work from occurring.
CVE-2013-0217 is a memory leak on an error path which is guest triggerable.

IMPACT

A malicious guest can mount a DoS affecting the entire system.

VULNERABLE SYSTEMS

All systems running guests with access to PV network devices are vulnerable.
CVE-2013-0216 affects both mainline (“pvops”) and classic-Xen patch kernels.
CVE-2013-0217 affects only mainline (“pvops”) kernels.