When polling event channels, in general arbitrary port numbers can be
specified. Specifically, there is no requirement that a polled event
channel ports has ever been created. When the code was generalised
from an earlier implementation, introducing some intermediate
pointers, a check should have been made that these intermediate
pointers are non-NULL. However, that check was omitted.
A malicious or buggy guest may cause the hypervisor to access
addresses it doesn't control, usually leading to a host crash (Denial
of Service). Information leaks cannot be excluded.
Xen versions 4.4 and newer are vulnerable. Xen versions 4.3 and
earlier are not affected.
Both x86 and ARM systems are vulnerable.
While all guest kinds can cause a Denial of Service, only x86 PV guests
may be able to leverage the possible information leaks.
There is no known mitigation.
Name: the Xen project
Upstream: Ankur Arora (Oracle)
Created xen tracking bugs for this issue:
Affects: fedora-all [bug 1463231]