CVE-2011-1763 kernel: xen: improper upper boundary check in get_free_port() function

[Eugene Teo <eugene () redhat com>]

A flaw was found in the way Xen hypervisor checked for upper boundary
when getting a new event channel port. A privileged DomU user could use
this flaws to cause denial of service or, possibly, increase his privileges.

AFAIK, upstream xen is not affected.

https://bugzilla.redhat.com/CVE-2011-1763

fix: xen-unstable c/s 19365:
http://xenbits.xensource.com/hg/xen-unstable.hg/rev/2dcdd2fcb945

Thanks, Eugene