Lets look at this play from 2 directions.

1. Rule it is a foul tip if the ball goes directly from the bat to the catchers glove or hand.

Now what if it misses the glove/hand and comes off his chest protector or mask.  It is not a catch only a strike and is ruled a foul ball.

What if it hits his glove then to chest protector/mask and back to his glove it is a catch and shall be ruled a foul tip.

Here is the rule out of the book:

(2) A third strike is legally caught by the catcher;

Rule 5.09(a)(2) Comment (Rule 6.05(b) Comment): “Legally caught” means in the catcher’s glove before the ball touches the ground. It is not legal if the ball lodges in his clothing or paraphernalia; or if it touches the umpire and is caught by the catcher on the rebound.

If a foul tip first strikes the catcher’s glove and then goes on through and is caught by both hands against his body or protector, before the ball touches the ground, it is a strike, and if third strike, batter is out. If smothered against his body or protector, it is a catch provided the ball struck the catcher’s glove or hand first.