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module OpenPGP (Message(..), Packet(..), SignatureSubpacket(..), HashAlgorithm(..), KeyAlgorithm(..), CompressionAlgorithm(..), MPI(..), fingerprint_material, signatures_and_data, signature_issuer) where
import Control.Monad
import Data.Bits
import Data.Word
import Data.Map (Map, (!))
import qualified Data.Map as Map
import qualified Data.ByteString.Lazy as LZ
import qualified Data.ByteString.Lazy.UTF8 as LZ (toString, fromString)
import Data.Binary
import Data.Binary.Get
import qualified Codec.Compression.Zlib.Raw as Zip
import qualified Codec.Compression.Zlib as Zlib
import qualified Codec.Compression.BZip as BZip2
import qualified BaseConvert as BaseConvert
data Packet =
SignaturePacket {
version::Word8,
signature_type::Word8,
key_algorithm::KeyAlgorithm,
hash_algorithm::HashAlgorithm,
hashed_subpackets::[SignatureSubpacket],
unhashed_subpackets::[SignatureSubpacket],
hash_head::Word16,
signature::MPI,
trailer::LZ.ByteString
} |
OnePassSignaturePacket {
version::Word8,
signature_type::Word8,
hash_algorithm::HashAlgorithm,
key_algorithm::KeyAlgorithm,
key_id::String,
nested::Word8
} |
PublicKeyPacket {
version::Word8,
timestamp::Word32,
key_algorithm::KeyAlgorithm,
key::Map Char MPI
} |
SecretKeyPacket {
version::Word8,
timestamp::Word32,
key_algorithm::KeyAlgorithm,
key::Map Char MPI,
s2k_useage::Word8,
symmetric_type::Word8,
s2k_type::Word8,
s2k_hash_algorithm::HashAlgorithm,
s2k_salt::Word64,
s2k_count::Word8,
encrypted_data::LZ.ByteString,
private_hash::LZ.ByteString
} |
CompressedDataPacket {
compression_algorithm::CompressionAlgorithm,
message::Message
} |
LiteralDataPacket {
format::Char,
filename::String,
timestamp::Word32,
content::LZ.ByteString
} |
UserIDPacket String
deriving (Show, Read, Eq)
instance Binary Packet where
put p = do
-- First two bits are 1 for new packet format
put ((tag .|. 0xC0) :: Word8)
-- Use 5-octet lengths
put (255 :: Word8)
put ((fromIntegral $ LZ.length body) :: Word32)
mapM_ putWord8 (LZ.unpack body)
where (body, tag) = put_packet p
get = do
tag <- get :: Get Word8
let (t, l) =
if (tag .&. 64) /= 0 then
(tag .&. 63, parse_new_length)
else
((tag `shiftR` 2) .&. 15, parse_old_length tag)
in do
len <- l
-- This forces the whole packet to be consumed
packet <- getLazyByteString (fromIntegral len)
return $ runGet (parse_packet t) packet
-- http://tools.ietf.org/html/rfc4880#section-4.2.2
parse_new_length :: Get Word32
parse_new_length = do
len <- fmap fromIntegral (get :: Get Word8)
case len of
-- One octet length
_ | len < 192 -> return len
-- Two octet length
_ | len > 191 && len < 224 -> do
second <- fmap fromIntegral (get :: Get Word8)
return $ ((len - 192) `shiftL` 8) + second + 192
-- Five octet length
_ | len == 255 -> get :: Get Word32
-- TODO: Partial body lengths. 1 << (len & 0x1F)
-- http://tools.ietf.org/html/rfc4880#section-4.2.1
parse_old_length :: Word8 -> Get Word32
parse_old_length tag =
case (tag .&. 3) of
-- One octet length
0 -> fmap fromIntegral (get :: Get Word8)
-- Two octet length
1 -> fmap fromIntegral (get :: Get Word16)
-- Four octet length
2 -> get
-- Indeterminate length
3 -> fmap fromIntegral remaining
-- http://tools.ietf.org/html/rfc4880#section-5.5.2
public_key_fields :: KeyAlgorithm -> [Char]
public_key_fields RSA = ['n', 'e']
public_key_fields RSA_E = public_key_fields RSA
public_key_fields RSA_S = public_key_fields RSA
public_key_fields ELGAMAL = ['p', 'g', 'y']
public_key_fields DSA = ['p', 'q', 'g', 'y']
-- http://tools.ietf.org/html/rfc4880#section-5.5.3
secret_key_fields :: KeyAlgorithm -> [Char]
secret_key_fields RSA = ['d', 'p', 'q', 'u']
secret_key_fields RSA_E = secret_key_fields RSA
secret_key_fields RSA_S = secret_key_fields RSA
secret_key_fields ELGAMAL = ['x']
secret_key_fields DSA = ['x']
-- Need this seperate for trailer calculation
signature_packet_start :: Packet -> LZ.ByteString
signature_packet_start (SignaturePacket {
version = 4,
signature_type = signature_type,
key_algorithm = key_algorithm,
hash_algorithm = hash_algorithm,
hashed_subpackets = hashed_subpackets
}) =
LZ.concat $ [
encode (0x04 :: Word8),
encode signature_type,
encode key_algorithm,
encode hash_algorithm,
encode ((fromIntegral $ LZ.length hashed_subs) :: Word16),
hashed_subs
]
where hashed_subs = LZ.concat $ map encode hashed_subpackets
-- The trailer is just the top of the body plus some crap
calculate_signature_trailer :: Packet -> LZ.ByteString
calculate_signature_trailer p =
LZ.concat [
signature_packet_start p,
encode (0x04 :: Word8),
encode (0xff :: Word8),
encode ((fromIntegral (LZ.length $ signature_packet_start p)) :: Word32)
]
put_packet :: (Num a) => Packet -> (LZ.ByteString, a)
put_packet (UserIDPacket txt) = (LZ.fromString txt, 13)
parse_packet :: Word8 -> Get Packet
-- SignaturePacket, http://tools.ietf.org/html/rfc4880#section-5.2
parse_packet 2 = do
version <- get
case version of
3 -> undefined -- TODO: V3 sigs
4 -> do
signature_type <- get
key_algorithm <- get
hash_algorithm <- get
hashed_size <- fmap fromIntegral (get :: Get Word16)
hashed_data <- getLazyByteString hashed_size
let hashed = runGet get_signature_subpackets hashed_data in do
unhashed_size <- fmap fromIntegral (get :: Get Word16)
unhashed_data <- getLazyByteString unhashed_size
let unhashed = runGet get_signature_subpackets unhashed_data in do
hash_head <- get
signature <- get
return (SignaturePacket {
version = version,
signature_type = signature_type,
key_algorithm = key_algorithm,
hash_algorithm = hash_algorithm,
hashed_subpackets = hashed,
unhashed_subpackets = unhashed,
hash_head = hash_head,
signature = signature,
trailer = LZ.concat [encode version, encode signature_type, encode key_algorithm, encode hash_algorithm, encode (fromIntegral hashed_size :: Word16), hashed_data, LZ.pack [4, 0xff], encode ((6 + (fromIntegral hashed_size)) :: Word32)]
})
-- OnePassSignaturePacket, http://tools.ietf.org/html/rfc4880#section-5.4
parse_packet 4 = do
version <- get
signature_type <- get
hash_algo <- get
key_algo <- get
key_id <- get :: Get Word64
nested <- get
return (OnePassSignaturePacket {
version = version,
signature_type = signature_type,
hash_algorithm = hash_algo,
key_algorithm = key_algo,
key_id = (BaseConvert.toString 16 key_id),
nested = nested
})
-- SecretKeyPacket, http://tools.ietf.org/html/rfc4880#section-5.5.3
parse_packet 5 = do
-- Parse PublicKey part
(PublicKeyPacket {
version = version,
timestamp = timestamp,
key_algorithm = algorithm,
key = key
}) <- parse_packet 6
s2k_useage <- get :: Get Word8
let k = SecretKeyPacket version timestamp algorithm key s2k_useage
in do
k' <- case s2k_useage of
_ | s2k_useage == 255 || s2k_useage == 254 -> do
symmetric_type <- get
s2k_type <- get
s2k_hash_algorithm <- get
s2k_salt <- if s2k_type == 1 || s2k_type == 3 then get
else return undefined
s2k_count <- if s2k_type == 3 then do
c <- fmap fromIntegral (get :: Get Word8)
return $ fromIntegral $
(16 + (c .&. 15)) `shiftL` ((c `shiftR` 4) + 6)
else return undefined
return (k symmetric_type s2k_type s2k_hash_algorithm
s2k_salt s2k_count)
_ | s2k_useage > 0 ->
-- s2k_useage is symmetric_type in this case
return (k s2k_useage undefined undefined undefined undefined)
_ ->
return (k undefined undefined undefined undefined undefined)
if s2k_useage > 0 then do
encrypted <- getRemainingLazyByteString
return (k' encrypted undefined)
else do
key <- foldM (\m f -> do
mpi <- get :: Get MPI
return $ Map.insert f mpi m) key (secret_key_fields algorithm)
private_hash <- getRemainingLazyByteString
return ((k' undefined private_hash) {key = key})
-- PublicKeyPacket, http://tools.ietf.org/html/rfc4880#section-5.5.2
parse_packet 6 = do
version <- get :: Get Word8
case version of
4 -> do
timestamp <- get
algorithm <- get
key <- mapM (\f -> do
mpi <- get :: Get MPI
return (f, mpi)) (public_key_fields algorithm)
return (PublicKeyPacket {
version = 4,
timestamp = timestamp,
key_algorithm = algorithm,
key = Map.fromList key
})
-- CompressedDataPacket, http://tools.ietf.org/html/rfc4880#section-5.6
parse_packet 8 = do
algorithm <- get
message <- getRemainingLazyByteString
let decompress = case algorithm of
Uncompressed -> id
ZIP -> Zip.decompress
ZLIB -> Zlib.decompress
BZip2 -> BZip2.decompress
in
return (CompressedDataPacket {
compression_algorithm = algorithm,
message = runGet (get :: Get Message) (decompress message)
})
-- LiteralDataPacket, http://tools.ietf.org/html/rfc4880#section-5.9
parse_packet 11 = do
format <- get
filenameLength <- get :: Get Word8
filename <- getLazyByteString (fromIntegral filenameLength)
timestamp <- get
content <- getRemainingLazyByteString
return (LiteralDataPacket {
format = format,
filename = LZ.toString filename,
timestamp = timestamp,
content = content
})
-- UserIDPacket, http://tools.ietf.org/html/rfc4880#section-5.11
parse_packet 13 =
fmap UserIDPacket (fmap LZ.toString getRemainingLazyByteString)
-- Fail nicely for unimplemented packets
parse_packet _ = fail "Unimplemented OpenPGP packet tag"
-- Helper method for fingerprints and such
fingerprint_material :: Packet -> [LZ.ByteString]
fingerprint_material (PublicKeyPacket {version = 4,
timestamp = timestamp,
key_algorithm = algorithm,
key = key}) =
[
LZ.singleton 0x99,
encode (6 + fromIntegral (LZ.length material) :: Word16),
LZ.singleton 4, encode timestamp, encode algorithm,
material
]
where material = LZ.concat $
map (\f -> encode (key ! f)) (public_key_fields algorithm)
fingerprint_material p | version p == 2 || version p == 3 = [n, e]
where n = LZ.drop 2 (encode (key p ! 'n'))
e = LZ.drop 2 (encode (key p ! 'e'))
data HashAlgorithm = MD5 | SHA1 | RIPEMD160 | SHA256 | SHA384 | SHA512 | SHA224
deriving (Show, Read, Eq)
instance Binary HashAlgorithm where
put MD5 = put (01 :: Word8)
put SHA1 = put (02 :: Word8)
put RIPEMD160 = put (03 :: Word8)
put SHA256 = put (08 :: Word8)
put SHA384 = put (09 :: Word8)
put SHA512 = put (10 :: Word8)
put SHA224 = put (11 :: Word8)
get = do
tag <- get :: Get Word8
case tag of
01 -> return MD5
02 -> return SHA1
03 -> return RIPEMD160
08 -> return SHA256
09 -> return SHA384
10 -> return SHA512
11 -> return SHA224
data KeyAlgorithm = RSA | RSA_E | RSA_S | ELGAMAL | DSA | ECC | ECDSA | DH
deriving (Show, Read, Eq)
instance Binary KeyAlgorithm where
put RSA = put (01 :: Word8)
put RSA_E = put (02 :: Word8)
put RSA_S = put (03 :: Word8)
put ELGAMAL = put (16 :: Word8)
put DSA = put (17 :: Word8)
put ECC = put (18 :: Word8)
put ECDSA = put (19 :: Word8)
put DH = put (21 :: Word8)
get = do
tag <- get :: Get Word8
case tag of
01 -> return RSA
02 -> return RSA_E
03 -> return RSA_S
16 -> return ELGAMAL
17 -> return DSA
18 -> return ECC
19 -> return ECDSA
21 -> return DH
data CompressionAlgorithm = Uncompressed | ZIP | ZLIB | BZip2
deriving (Show, Read, Eq)
instance Binary CompressionAlgorithm where
put Uncompressed = put (0 :: Word8)
put ZIP = put (1 :: Word8)
put ZLIB = put (2 :: Word8)
put BZip2 = put (3 :: Word8)
get = do
tag <- get :: Get Word8
case tag of
0 -> return Uncompressed
1 -> return ZIP
2 -> return ZLIB
3 -> return BZip2
-- A message is encoded as a list that takes the entire file
newtype Message = Message [Packet] deriving (Show, Read, Eq)
instance Binary Message where
put (Message []) = return ()
put (Message (x:xs)) = do
put x
put (Message xs)
get = do
done <- isEmpty
if done then do
return (Message [])
else do
next_packet <- get :: Get Packet
(Message tail) <- get :: Get Message
return (Message (next_packet:tail))
signatures_and_data :: Message -> ([Packet], [Packet])
signatures_and_data (Message ((CompressedDataPacket {message = m}):_)) =
signatures_and_data m
signatures_and_data (Message lst) =
(filter isSig lst, filter isDta lst)
where isSig (SignaturePacket {}) = True
isSig _ = False
isDta (LiteralDataPacket {}) = True
isDta _ = False
newtype MPI = MPI Integer deriving (Show, Read, Eq, Ord)
instance Binary MPI where
put (MPI i) = do
put (((fromIntegral . LZ.length $ bytes) - 1) * 8
+ floor (logBase 2 $ fromIntegral (bytes `LZ.index` 0))
+ 1 :: Word16)
mapM_ putWord8 (LZ.unpack bytes)
where bytes = LZ.unfoldr (\x -> if x == 0 then Nothing
else Just (fromIntegral x, x `shiftR` 8)) i
get = do
length <- fmap fromIntegral (get :: Get Word16)
bytes <- getLazyByteString (floor ((length + 7) / 8))
return (MPI (LZ.foldr (\b a ->
a `shiftL` 8 .|. fromIntegral b) 0 bytes))
data SignatureSubpacket =
SignatureCreationTimePacket Word32 |
IssuerPacket String
deriving (Show, Read, Eq)
instance Binary SignatureSubpacket where
put p = do
-- Use 5-octet-length + 1 for tag as the first packet body octet
put (255 :: Word8)
put ((fromIntegral $ LZ.length body) + 1 :: Word32)
put tag
mapM_ putWord8 (LZ.unpack body)
where (body, tag) = put_signature_subpacket p
get = do
len <- fmap fromIntegral (get :: Get Word8)
len <- case len of
_ | len > 190 && len < 255 -> do -- Two octet length
second <- fmap fromIntegral (get :: Get Word8)
return $ ((len - 192) `shiftR` 8) + second + 192
255 -> -- Five octet length
fmap fromIntegral (get :: Get Word32)
_ -> -- One octet length, no furthur processing
return len
tag <- get :: Get Word8
-- This forces the whole packet to be consumed
packet <- getLazyByteString len
return $ runGet (parse_signature_subpacket tag) packet
signature_issuer :: OpenPGP.Packet -> Maybe String
signature_issuer (SignaturePacket {hashed_subpackets = hashed,
unhashed_subpackets = unhashed}) =
if (length issuers) > 0 then Just issuer else Nothing
where IssuerPacket issuer = issuers !! 0
issuers = (filter isIssuer hashed) ++ (filter isIssuer unhashed)
isIssuer (IssuerPacket {}) = True
isIssuer _ = False
put_signature_subpacket :: SignatureSubpacket -> (LZ.ByteString, Word8)
put_signature_subpacket (SignatureCreationTimePacket time) =
(encode time, 2)
put_signature_subpacket (IssuerPacket keyid) =
(encode ((BaseConvert.toNum 16 keyid) :: Word64), 16)
get_signature_subpackets :: Get [SignatureSubpacket]
get_signature_subpackets = do
done <- isEmpty
if done then do
return []
else do
next_packet <- get :: Get SignatureSubpacket
tail <- get_signature_subpackets
return (next_packet:tail)
parse_signature_subpacket :: Word8 -> Get SignatureSubpacket
-- SignatureCreationTimePacket, http://tools.ietf.org/html/rfc4880#section-5.2.3.4
parse_signature_subpacket 2 = fmap SignatureCreationTimePacket get
-- IssuerPacket, http://tools.ietf.org/html/rfc4880#section-5.2.3.5
parse_signature_subpacket 16 = do
keyid <- get :: Get Word64
return $ IssuerPacket (BaseConvert.toString 16 keyid)
-- Fail nicely for unimplemented packets
parse_signature_subpacket _ =
fail "Unimplemented OpenPGP signature subpacket tag"
|