So far nobody on the set involved in the making of THE DARK KNIGHT RISES knows the ending of the movie. Except of course, Christopher Nolan himself. According to his co-star Gary Oldman who plays Commissioner Jim Gordon in the movie, Nolan has refused to hand out any scripts detailing the ending as he wants it to keep it secret. It's understandable that Nolan does this to minimize the chance of leaks circulating all over the place.
Here's what Oldman had to say about Nolan's decision for doing so.
Christopher doesn't want anyone to ruin it and I completely understand that.
The newer people on the film go to his office to read the script. They sent mine out, but it had to be hand delivered directly to me and nobody else. And the final few pages were missing.
I went along and talked to Christopher and in person about the ending. Then I locked it away in my head.
Well, personally, I agree that Nolan did the right thing for keeping the ending a secret. After all, such move builds a great deal of anticipation that made the curiosity all the more exciting factor!