From the perspective of the law, the same rules apply across the board.
A warrant only matters when the case is brought before the court. IOW, it only matter when the government gets caught, or brings a case into court itself.
I got down in the weeds following a set of cases against the NSA, about 10 of them, were consolidated. FISA has civil damages for people "aggrieved," meaning surveilled without a warrant. FISA has civil damages to deter "illegal" surveillance.
The government successfully had the cases tossed on state secrets grounds.
The only cases I know of that maybe involved CIA were physical searches of property of US persons, done overseas. Allowed.
Thank you. Brennan showing up to itch on the Sunday mass news shows, cause me to wonder just who he was talking to.