CVE-2020-11743

An issue was discovered in Xen through 4.13.x, allowing guest OS users to
cause a denial of service because of a bad error path in
GNTTABOP_map_grant. Grant table operations are expected to return 0 for
success, and a negative number for errors. Some misplaced brackets cause
one error path to return 1 instead of a negative value. The grant table
code in Linux treats this condition as success, and proceeds with
incorrectly initialised state. A buggy or malicious guest can construct its
grant table in such a way that, when a backend domain tries to map a grant,
it hits the incorrect error path. This will crash a Linux based dom0 or
backend domain.

Notes