Zehaf-Bibeau's long criminal record for a series of crimes, including drug possession, robbery and assault, barred him from owning or possessing a gun.
-from "Police: Canadian terror attack driven by ideology" on the USA Today website today.
I think the author of this quote meant to say that his criminal record made it "against the law for him to own or posses a gun." Obviously, he wasn't "barred" from anything. So much for gun laws in Canada.