How to block access to Facebook, but leave the ability to log in to the site?

Question

Facebook

I am developing a hotspot service with authorization through social networks, in particular through Facebook. The scheme is simple: the user logs in to the portal through a social network account and access to the Internet is opened for him.
But during the authorization process, the user needs access to the https://www.facebook.com/dialog/oauth page, and given that ssl is there, the entire domain will have to be opened. Are there any ways to leave the possibility of authorization without opening full access to the entire social network?