bind: fix CVE-2020-8616/7

fix CVE-2020-8616 and CVE-2020-8617

Signed-off-by: Lee Chee Yang <chee.yang.lee@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit d0df8318)
Signed-off-by: Steve Sakoman <steve@sakoman.com>