If it wasn't Rockefeller, it was someone very close to him that was briefed on the program, present where Rockefeller was able to air these concerns, and inclined to leak the information.
That's a list of people so short you don't even need to take your shoes off to count them.
Also, don't believe the NY Times when they attempt to narrow the leaker down to "a dozen or so current or former" whatever, and all that crap. Senators have the biggest mouths in the world. It is the only way they can get their boring, braggadocios asses invited to Washington parties. Do you really want to believe that members of the Intelligence committed did not share the domestic surveillance program with other Senators? Especially those Senators who have both a personal and professional stake in damaging the White House?
I have NO proof of who the leaker might be, but I will tell you who I think it is. I think it is the Senator who wants to be President, but cant win as a Democrat, and wont win as a Republican either, but intends to run as an Independent on the premise that both sides are dysfunctional.
John McCain.