So there was a mass shooting in Nova Scotia. Doesn't Canada have gun control laws?

Fairly strict gun control laws that I am actually not much familiar with though. Quite a few years ago I bought a 303 rifle at a garage sale illegally. The seller just wanted to get rid of it. 
Anybody can get a gun,  just keep asking around and you probably will find someone willing to sell (get rid of) an unregistered gun.

Gun laws do not stop criminals. 

Yes, they do.
And, according to what I read, before this shooting with at least 18 dead, the worst mass shooting in Canada was in 1989 and had 14 victims.
Compared to some countries' records of mass shootings, that sounds, in some ways, sort of good in comparison. Though nothing is good about mass shootings.