Information disclosure in my friends pagination script

There are three problems with this script:
1. It takes a block id, but doesn't check that the logged-in user is allowed to see the view that the block appears in.
2. It takes a user id, and doesn't check that the user id matches the id of the view owner.
3. It returns a list of friends with too much information; it should only return the html to replace the block content.

Does not affect Mahara 1.2 (there was no friends block pagination).