Is there an easy way to fix a leaky chimney base on the roof?

The chimney is brick,with a metal wrap at the roof,and is mainly in the garage.I can only do small repairs due to a car accident not yet recovered,so hammering down tarp with boards,etc,is out of the question.Could I use a sealant?If so,what kind? This is just a temporary fix until I can have the roof replaced,it's very wet out here in winters.It's ruining my woodstove insert .