module Network.HTTP.MD5 (md5ss, md5si, md5bs, md5bi) where import Data.Char (ord, chr) import Data.Bits (rotateL, shiftL, shiftR, (.&.), (.|.), xor, complement) import Data.Word (Word32, Word64) import qualified Data.ByteString.Lazy as BS import GHC.Show import System.IO import System.IO.Unsafe ( unsafePerformIO ) import Network.HTTP.Utils -- ===================== TYPES AND CLASS DEFINTIONS ======================== type Rotation = Int data XYZ = XYZ {-# UNPACK #-} !Word32 {-# UNPACK #-} !Word32 {-# UNPACK #-} !Word32 data ABCD = ABCD {-# UNPACK #-} !Word32 {-# UNPACK #-} !Word32 {-# UNPACK #-} !Word32 {-# UNPACK #-} !Word32 deriving (Eq, Show) addABCD :: ABCD -> ABCD -> ABCD addABCD (ABCD a1 b1 c1 d1) (ABCD a2 b2 c2 d2) = ABCD (a1 + a2) (b1 + b2) (c1 + c2) (d1 + d2) -- ===================== EXPORTED FUNCTIONS ======================== md5 :: BS.ByteString -> ABCD md5 m = md5_main 0 magic_numbers m -- | Encodes a string given the encoding and returns an MD5 hex number -- à la md5sum program md5ss :: TextEncoding -> String -> String md5ss enc s = (abcd_to_string . md5) (unsafePerformIO (encodeString enc s)) -- | Returns an MD5 hex number of a byte string à la md5sum program md5bs :: BS.ByteString -> String md5bs = abcd_to_string . md5 -- | Encodes a string given the encoding and returns an MD5 hex number -- à la md5sum program md5si :: TextEncoding -> String -> Integer md5si enc s = (abcd_to_integer . md5) (unsafePerformIO (encodeString enc s)) -- | Returns an MD5 hex number of a byte string à la md5sum program md5bi :: BS.ByteString -> Integer md5bi = abcd_to_integer . md5 -- ===================== THE CORE ALGORITHM ======================== -- Decides what to do. The first argument indicates if padding has been -- added. The second is the length mod 2^64 so far. Then we have the -- starting state, the rest of the string and the final state. md5_main :: Word64 -- The length so far mod 2^64 -> ABCD -- The initial state -> BS.ByteString -- The non-processed portion of the message -> ABCD -- The resulting state md5_main ilen abcd bs | BS.null bs = abcd | otherwise = md5_main (ilen + 512) (addABCD abcd abcd') bs' where (m16, bs') = get_next 16 bs abcd' = md5_do_block abcd m16 get_next 0 bs = ([],bs) get_next n bs | len == 4 = let (ws,bs'') = get_next (n-1) bs' in (w:ws,bs'') | zeros < 14 = let ws = replicate (fromIntegral zeros) 0++size in (w1:ws,BS.empty) | otherwise = let ws = replicate (fromIntegral n-1) 0 bs = BS.append (BS.replicate 56 0) (length_to_bytes 8 c64) in (w1:ws, bs) where (s, bs') = BS.splitAt 4 bs len = fromIntegral (BS.length s) w = BS.foldr (\c w -> shiftL w 8 + fromIntegral c) 0 s w1 = shiftL 0x80 (len * 8) + w c64 = ilen + 32 * (16 - n) + 8 * fromIntegral len c64' = ilen + 32 * (16 - n) + 32 zeros = shiftR ((448 - c64') .&. 511) 5 size = [ fromIntegral (c64 .&. 0xFFFFFFFF) , fromIntegral (shiftR c64 32) ] length_to_bytes 0 _ = BS.empty length_to_bytes p n = BS.cons this (length_to_bytes (p-1) (shiftR n 8)) where this = fromIntegral (n .&. 255) -- md5_do_block processes a 512 bit block by calling md5_round 4 times to -- apply each round with the correct constants and permutations of the -- block md5_do_block :: ABCD -- Initial state -> [Word32] -- The block to be processed - 16 32bit words -> ABCD -- Resulting state md5_do_block abcd0 w = abcd4 where (r1, r2, r3, r4) = rounds perm5 [c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15] = [c1,c6,c11,c0,c5,c10,c15,c4,c9,c14,c3,c8,c13,c2,c7,c12] perm5 _ = error "broke at perm5" perm3 [c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15] = [c5,c8,c11,c14,c1,c4,c7,c10,c13,c0,c3,c6,c9,c12,c15,c2] perm3 _ = error "broke at perm3" perm7 [c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15] = [c0,c7,c14,c5,c12,c3,c10,c1,c8,c15,c6,c13,c4,c11,c2,c9] perm7 _ = error "broke at perm7" abcd1 = md5_round md5_f abcd0 w r1 abcd2 = md5_round md5_g abcd1 (perm5 w) r2 abcd3 = md5_round md5_h abcd2 (perm3 w) r3 abcd4 = md5_round md5_i abcd3 (perm7 w) r4 -- md5_round does one of the rounds. It takes an auxiliary function and foldls -- (md5_inner_function f) to repeatedly apply it to the initial state with the -- correct constants md5_round :: (XYZ -> Word32) -- Auxiliary function (F, G, H or I -- for those of you with a copy of -- the prayer book^W^WRFC) -> ABCD -- Initial state -> [Word32] -- The 16 32bit words of input -> [(Rotation, Word32)] -- The list of 16 rotations and -- additive constants -> ABCD -- Resulting state md5_round f abcd s ns = foldl (md5_inner_function f) abcd ns' where ns' = zipWith (\x (y, z) -> (y, x + z)) s ns -- Apply one of the functions md5_[fghi] and put the new ABCD together md5_inner_function :: (XYZ -> Word32) -- Auxiliary function -> ABCD -- Initial state -> (Rotation, Word32) -- The rotation and additive -- constant (X[i] + T[j]) -> ABCD -- Resulting state md5_inner_function f (ABCD a b c d) (s, ki) = ABCD d a' b c where mid_a = a + f (XYZ b c d) + ki rot_a = rotateL mid_a s a' = b + rot_a -- The 4 auxiliary functions md5_f :: XYZ -> Word32 md5_f (XYZ x y z) = z `xor` (x .&. (y `xor` z)) {- optimised version of: (x .&. y) .|. ((complement x) .&. z) -} md5_g :: XYZ -> Word32 md5_g (XYZ x y z) = md5_f (XYZ z x y) {- was: (x .&. z) .|. (y .&. (complement z)) -} md5_h :: XYZ -> Word32 md5_h (XYZ x y z) = x `xor` y `xor` z md5_i :: XYZ -> Word32 md5_i (XYZ x y z) = y `xor` (x .|. (complement z)) -- The magic numbers from the RFC. magic_numbers :: ABCD magic_numbers = ABCD 0x67452301 0xefcdab89 0x98badcfe 0x10325476 -- The 4 lists of (rotation, additive constant) tuples, one for each round rounds :: ([(Rotation, Word32)], [(Rotation, Word32)], [(Rotation, Word32)], [(Rotation, Word32)]) rounds = (r1, r2, r3, r4) where r1 = [(s11, 0xd76aa478), (s12, 0xe8c7b756), (s13, 0x242070db), (s14, 0xc1bdceee), (s11, 0xf57c0faf), (s12, 0x4787c62a), (s13, 0xa8304613), (s14, 0xfd469501), (s11, 0x698098d8), (s12, 0x8b44f7af), (s13, 0xffff5bb1), (s14, 0x895cd7be), (s11, 0x6b901122), (s12, 0xfd987193), (s13, 0xa679438e), (s14, 0x49b40821)] r2 = [(s21, 0xf61e2562), (s22, 0xc040b340), (s23, 0x265e5a51), (s24, 0xe9b6c7aa), (s21, 0xd62f105d), (s22, 0x2441453), (s23, 0xd8a1e681), (s24, 0xe7d3fbc8), (s21, 0x21e1cde6), (s22, 0xc33707d6), (s23, 0xf4d50d87), (s24, 0x455a14ed), (s21, 0xa9e3e905), (s22, 0xfcefa3f8), (s23, 0x676f02d9), (s24, 0x8d2a4c8a)] r3 = [(s31, 0xfffa3942), (s32, 0x8771f681), (s33, 0x6d9d6122), (s34, 0xfde5380c), (s31, 0xa4beea44), (s32, 0x4bdecfa9), (s33, 0xf6bb4b60), (s34, 0xbebfbc70), (s31, 0x289b7ec6), (s32, 0xeaa127fa), (s33, 0xd4ef3085), (s34, 0x4881d05), (s31, 0xd9d4d039), (s32, 0xe6db99e5), (s33, 0x1fa27cf8), (s34, 0xc4ac5665)] r4 = [(s41, 0xf4292244), (s42, 0x432aff97), (s43, 0xab9423a7), (s44, 0xfc93a039), (s41, 0x655b59c3), (s42, 0x8f0ccc92), (s43, 0xffeff47d), (s44, 0x85845dd1), (s41, 0x6fa87e4f), (s42, 0xfe2ce6e0), (s43, 0xa3014314), (s44, 0x4e0811a1), (s41, 0xf7537e82), (s42, 0xbd3af235), (s43, 0x2ad7d2bb), (s44, 0xeb86d391)] s11 = 7 s12 = 12 s13 = 17 s14 = 22 s21 = 5 s22 = 9 s23 = 14 s24 = 20 s31 = 4 s32 = 11 s33 = 16 s34 = 23 s41 = 6 s42 = 10 s43 = 15 s44 = 21 -- Turn the 4 32 bit words into a string representing the hex number they -- represent. abcd_to_string :: ABCD -> String abcd_to_string (ABCD a b c d) = (show_hex a . show_hex b . show_hex c . show_hex d) "" where show_hex w = showIt (rev_num w) 8 where showIt _ 0 r = r showIt n i r = c `seq` showIt n' (i-1) (c : r) where (n',d) = quotRem n 16 c = intToDigit (fromIntegral d) -- Convert to an integer, performing endianness magic as we go abcd_to_integer :: ABCD -> Integer abcd_to_integer (ABCD a b c d) = toInteger (rev_num a) * 2^(96 :: Int) + toInteger (rev_num b) * 2^(64 :: Int) + toInteger (rev_num c) * 2^(32 :: Int) + toInteger (rev_num d) rev_num :: Word32 -> Word32 rev_num i = j where j = shiftL (i .&. 0x000000FF) 24 .|. shiftL (i .&. 0x0000FF00) 8 .|. shiftR (i .&. 0x00FF0000) 8 .|. shiftR (i .&. 0xFF000000) 24