In Homeland, I can't remember whether Carrie knows about the drone strike Estes and Walden authorised way back. I know Saul has seen the recordings but does Carrie know about this operation, either from Saul or Brody ?
Currently, Carrie does not know anything about the drone strike. Her thoughts for why Brody turned are because Brody was broken and became grateful to the man that 'rescued' him from his torture.
It seems the only people left alive that know about the strike, as of S2E12, is Saul, with Quinn having an idea that the hit on Brody is for something 'personal' to Estes.