hs-tls/core/Network/TLS/Packet.hs
2013-05-19 08:05:46 +01:00

555 lines
22 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
-- |
-- Module : Network.TLS.Packet
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : unknown
--
-- the Packet module contains everything necessary to serialize and deserialize things
-- with only explicit parameters, no TLS state is involved here.
--
module Network.TLS.Packet
(
-- * params for encoding and decoding
CurrentParams(..)
-- * marshall functions for header messages
, decodeHeader
, decodeDeprecatedHeaderLength
, decodeDeprecatedHeader
, encodeHeader
, encodeHeaderNoVer -- use for SSL3
-- * marshall functions for alert messages
, decodeAlert
, decodeAlerts
, encodeAlerts
-- * marshall functions for handshake messages
, decodeHandshakes
, decodeHandshake
, decodeDeprecatedHandshake
, encodeHandshake
, encodeHandshakes
, encodeHandshakeHeader
, encodeHandshakeContent
-- * marshall functions for change cipher spec message
, decodeChangeCipherSpec
, encodeChangeCipherSpec
, decodePreMasterSecret
, encodePreMasterSecret
-- * generate things for packet content
, generateMasterSecret
, generateKeyBlock
, generateClientFinished
, generateServerFinished
, generateCertificateVerify_SSL
) where
import Network.TLS.Struct
import Network.TLS.Wire
import Network.TLS.Cap
import Data.Maybe (fromJust)
import Data.Word
import Data.Bits ((.|.))
import Control.Applicative ((<$>))
import Control.Monad
import Data.ASN1.Types (fromASN1, toASN1)
import Data.ASN1.Encoding (decodeASN1', encodeASN1')
import Data.ASN1.BinaryEncoding (DER(..))
import Data.X509 (CertificateChainRaw(..), encodeCertificateChain, decodeCertificateChain)
import Network.TLS.Crypto
import Network.TLS.MAC
import Network.TLS.Cipher (CipherKeyExchangeType(..))
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as BC
import qualified Crypto.Hash.SHA1 as SHA1
import qualified Crypto.Hash.MD5 as MD5
data CurrentParams = CurrentParams
{ cParamsVersion :: Version -- ^ current protocol version
, cParamsKeyXchgType :: CipherKeyExchangeType -- ^ current key exchange type
, cParamsSupportNPN :: Bool -- ^ support Next Protocol Negotiation extension
} deriving (Show,Eq)
{- marshall helpers -}
getVersion :: Get Version
getVersion = do
major <- getWord8
minor <- getWord8
case verOfNum (major, minor) of
Nothing -> fail ("invalid version : " ++ show major ++ "," ++ show minor)
Just v -> return v
putVersion :: Version -> Put
putVersion ver = putWord8 major >> putWord8 minor
where (major, minor) = numericalVer ver
getHeaderType :: Get ProtocolType
getHeaderType = do
ty <- getWord8
case valToType ty of
Nothing -> fail ("invalid header type: " ++ show ty)
Just t -> return t
putHeaderType :: ProtocolType -> Put
putHeaderType = putWord8 . valOfType
getHandshakeType :: Get HandshakeType
getHandshakeType = do
ty <- getWord8
case valToType ty of
Nothing -> fail ("invalid handshake type: " ++ show ty)
Just t -> return t
{-
- decode and encode headers
-}
decodeHeader :: ByteString -> Either TLSError Header
decodeHeader = runGetErr "header" $ liftM3 Header getHeaderType getVersion getWord16
decodeDeprecatedHeaderLength :: ByteString -> Either TLSError Word16
decodeDeprecatedHeaderLength = runGetErr "deprecatedheaderlength" $ subtract 0x8000 <$> getWord16
decodeDeprecatedHeader :: Word16 -> ByteString -> Either TLSError Header
decodeDeprecatedHeader size =
runGetErr "deprecatedheader" $ do
1 <- getWord8
version <- getVersion
return $ Header ProtocolType_DeprecatedHandshake version size
encodeHeader :: Header -> ByteString
encodeHeader (Header pt ver len) = runPut (putHeaderType pt >> putVersion ver >> putWord16 len)
{- FIXME check len <= 2^14 -}
encodeHeaderNoVer :: Header -> ByteString
encodeHeaderNoVer (Header pt _ len) = runPut (putHeaderType pt >> putWord16 len)
{- FIXME check len <= 2^14 -}
{-
- decode and encode ALERT
-}
decodeAlert :: Get (AlertLevel, AlertDescription)
decodeAlert = do
al <- getWord8
ad <- getWord8
case (valToType al, valToType ad) of
(Just a, Just d) -> return (a, d)
(Nothing, _) -> fail "cannot decode alert level"
(_, Nothing) -> fail "cannot decode alert description"
decodeAlerts :: ByteString -> Either TLSError [(AlertLevel, AlertDescription)]
decodeAlerts = runGetErr "alerts" $ loop
where loop = do
r <- remaining
if r == 0
then return []
else liftM2 (:) decodeAlert loop
encodeAlerts :: [(AlertLevel, AlertDescription)] -> ByteString
encodeAlerts l = runPut $ mapM_ encodeAlert l
where encodeAlert (al, ad) = putWord8 (valOfType al) >> putWord8 (valOfType ad)
{- decode and encode HANDSHAKE -}
decodeHandshakeHeader :: Get (HandshakeType, Bytes)
decodeHandshakeHeader = do
ty <- getHandshakeType
content <- getOpaque24
return (ty, content)
decodeHandshakes :: ByteString -> Either TLSError [(HandshakeType, Bytes)]
decodeHandshakes b = runGetErr "handshakes" getAll b where
getAll = do
x <- decodeHandshakeHeader
empty <- isEmpty
if empty
then return [x]
else liftM ((:) x) getAll
decodeHandshake :: CurrentParams -> HandshakeType -> ByteString -> Either TLSError Handshake
decodeHandshake cp ty = runGetErr "handshake" $ case ty of
HandshakeType_HelloRequest -> decodeHelloRequest
HandshakeType_ClientHello -> decodeClientHello
HandshakeType_ServerHello -> decodeServerHello
HandshakeType_Certificate -> decodeCertificates
HandshakeType_ServerKeyXchg -> decodeServerKeyXchg cp
HandshakeType_CertRequest -> decodeCertRequest cp
HandshakeType_ServerHelloDone -> decodeServerHelloDone
HandshakeType_CertVerify -> decodeCertVerify cp
HandshakeType_ClientKeyXchg -> decodeClientKeyXchg
HandshakeType_Finished -> decodeFinished
HandshakeType_NPN -> do
unless (cParamsSupportNPN cp) $ fail "unsupported handshake type"
decodeNextProtocolNegotiation
decodeDeprecatedHandshake :: ByteString -> Either TLSError Handshake
decodeDeprecatedHandshake b = runGetErr "deprecatedhandshake" getDeprecated b where
getDeprecated = do
1 <- getWord8
ver <- getVersion
cipherSpecLen <- fromEnum <$> getWord16
sessionIdLen <- fromEnum <$> getWord16
challengeLen <- fromEnum <$> getWord16
ciphers <- getCipherSpec cipherSpecLen
session <- getSessionId sessionIdLen
random <- getChallenge challengeLen
let compressions = [0]
return $ ClientHello ver random session ciphers compressions [] (Just b)
getCipherSpec len | len < 3 = return []
getCipherSpec len = do
[c0,c1,c2] <- map fromEnum <$> replicateM 3 getWord8
([ toEnum $ c1 * 0x100 + c2 | c0 == 0 ] ++) <$> getCipherSpec (len - 3)
getSessionId 0 = return $ Session Nothing
getSessionId len = Session . Just <$> getBytes len
getChallenge len | 32 < len = getBytes (len - 32) >> getChallenge 32
getChallenge len = ClientRandom . B.append (B.replicate (32 - len) 0) <$> getBytes len
decodeHelloRequest :: Get Handshake
decodeHelloRequest = return HelloRequest
decodeClientHello :: Get Handshake
decodeClientHello = do
ver <- getVersion
random <- getClientRandom32
session <- getSession
ciphers <- getWords16
compressions <- getWords8
r <- remaining
exts <- if hasHelloExtensions ver && r > 0
then fmap fromIntegral getWord16 >>= getExtensions
else return []
return $ ClientHello ver random session ciphers compressions exts Nothing
decodeServerHello :: Get Handshake
decodeServerHello = do
ver <- getVersion
random <- getServerRandom32
session <- getSession
cipherid <- getWord16
compressionid <- getWord8
r <- remaining
exts <- if hasHelloExtensions ver && r > 0
then fmap fromIntegral getWord16 >>= getExtensions
else return []
return $ ServerHello ver random session cipherid compressionid exts
decodeServerHelloDone :: Get Handshake
decodeServerHelloDone = return ServerHelloDone
decodeCertificates :: Get Handshake
decodeCertificates = do
certsRaw <- CertificateChainRaw <$> (getWord24 >>= \len -> getList (fromIntegral len) getCertRaw)
case decodeCertificateChain certsRaw of
Left (i, s) -> fail ("error certificate parsing " ++ show i ++ ":" ++ s)
Right cc -> return $ Certificates cc
where getCertRaw = getOpaque24 >>= \cert -> return (3 + B.length cert, cert)
decodeFinished :: Get Handshake
decodeFinished = Finished <$> (remaining >>= getBytes)
decodeNextProtocolNegotiation :: Get Handshake
decodeNextProtocolNegotiation = do
opaque <- getOpaque8
_ <- getOpaque8 -- ignore padding
return $ HsNextProtocolNegotiation opaque
getSignatureHashAlgorithm :: Get HashAndSignatureAlgorithm
getSignatureHashAlgorithm = do
h <- fromJust . valToType <$> getWord8
s <- fromJust . valToType <$> getWord8
return (h,s)
decodeCertRequest :: CurrentParams -> Get Handshake
decodeCertRequest cp = do
certTypes <- map (fromJust . valToType . fromIntegral) <$> getWords8
sigHashAlgs <- if cParamsVersion cp >= TLS12
then Just <$> (getWord16 >>= getSignatureHashAlgorithms)
else return Nothing
dNameLen <- getWord16
-- FIXME: Decide whether to remove this check completely or to make it an option.
-- when (cParamsVersion cp < TLS12 && dNameLen < 3) $ fail "certrequest distinguishname not of the correct size"
dNames <- getList (fromIntegral dNameLen) getDName
return $ CertRequest certTypes sigHashAlgs dNames
where
getSignatureHashAlgorithms len = getList (fromIntegral len) (getSignatureHashAlgorithm >>= \sh -> return (2, sh))
getDName = do
dName <- getOpaque16
when (B.length dName == 0) $ fail "certrequest: invalid DN length"
dn <- case decodeASN1' DER dName of
Left e -> fail ("cert request decoding DistinguishedName ASN1 failed: " ++ show e)
Right asn1s -> case fromASN1 asn1s of
Left e -> fail ("cert request parsing DistinguishedName ASN1 failed: " ++ show e)
Right (d,_) -> return d
return (2 + B.length dName, dn)
decodeCertVerify :: CurrentParams -> Get Handshake
decodeCertVerify cp = do
mbHashSig <- if cParamsVersion cp >= TLS12
then Just <$> getSignatureHashAlgorithm
else return Nothing
bs <- getOpaque16
return $ CertVerify mbHashSig (CertVerifyData bs)
decodeClientKeyXchg :: Get Handshake
decodeClientKeyXchg = ClientKeyXchg <$> (remaining >>= getBytes)
os2ip :: ByteString -> Integer
os2ip = B.foldl' (\a b -> (256 * a) .|. (fromIntegral b)) 0
decodeServerKeyXchg_DH :: Get ServerDHParams
decodeServerKeyXchg_DH = do
p <- getOpaque16
g <- getOpaque16
y <- getOpaque16
return $ ServerDHParams { dh_p = os2ip p, dh_g = os2ip g, dh_Ys = os2ip y }
decodeServerKeyXchg_RSA :: Get ServerRSAParams
decodeServerKeyXchg_RSA = do
modulus <- getOpaque16
expo <- getOpaque16
return $ ServerRSAParams { rsa_modulus = os2ip modulus, rsa_exponent = os2ip expo }
decodeServerKeyXchg :: CurrentParams -> Get Handshake
decodeServerKeyXchg cp = ServerKeyXchg <$> case cParamsKeyXchgType cp of
CipherKeyExchange_RSA -> SKX_RSA . Just <$> decodeServerKeyXchg_RSA
CipherKeyExchange_DH_Anon -> SKX_DH_Anon <$> decodeServerKeyXchg_DH
CipherKeyExchange_DHE_RSA -> do
dhparams <- decodeServerKeyXchg_DH
signature <- getOpaque16
return $ SKX_DHE_RSA dhparams (B.unpack signature)
CipherKeyExchange_DHE_DSS -> do
dhparams <- decodeServerKeyXchg_DH
signature <- getOpaque16
return $ SKX_DHE_DSS dhparams (B.unpack signature)
_ -> do
bs <- remaining >>= getBytes
return $ SKX_Unknown bs
encodeHandshake :: Handshake -> ByteString
encodeHandshake o =
let content = runPut $ encodeHandshakeContent o in
let len = fromIntegral $ B.length content in
let header = case o of
ClientHello _ _ _ _ _ _ (Just _) -> "" -- SSLv2 ClientHello message
_ -> runPut $ encodeHandshakeHeader (typeOfHandshake o) len in
B.concat [ header, content ]
encodeHandshakes :: [Handshake] -> ByteString
encodeHandshakes hss = B.concat $ map encodeHandshake hss
encodeHandshakeHeader :: HandshakeType -> Int -> Put
encodeHandshakeHeader ty len = putWord8 (valOfType ty) >> putWord24 len
encodeHandshakeContent :: Handshake -> Put
encodeHandshakeContent (ClientHello _ _ _ _ _ _ (Just deprecated)) = do
putBytes deprecated
encodeHandshakeContent (ClientHello version random session cipherIDs compressionIDs exts Nothing) = do
putVersion version
putClientRandom32 random
putSession session
putWords16 cipherIDs
putWords8 compressionIDs
putExtensions exts
return ()
encodeHandshakeContent (ServerHello version random session cipherID compressionID exts) =
putVersion version >> putServerRandom32 random >> putSession session
>> putWord16 cipherID >> putWord8 compressionID
>> putExtensions exts >> return ()
encodeHandshakeContent (Certificates cc) = putOpaque24 (runPut $ mapM_ putOpaque24 certs)
where (CertificateChainRaw certs) = encodeCertificateChain cc
encodeHandshakeContent (ClientKeyXchg content) = do
putBytes content
encodeHandshakeContent (ServerKeyXchg _) = do
-- FIXME
return ()
encodeHandshakeContent (HelloRequest) = return ()
encodeHandshakeContent (ServerHelloDone) = return ()
encodeHandshakeContent (CertRequest certTypes sigAlgs certAuthorities) = do
putWords8 (map valOfType certTypes)
case sigAlgs of
Nothing -> return ()
Just l -> putWords16 $ map (\(x,y) -> (fromIntegral $ valOfType x) * 256 + (fromIntegral $ valOfType y)) l
encodeCertAuthorities certAuthorities
where
-- Convert a distinguished name to its DER encoding.
encodeCA dn = return $ encodeASN1' DER (toASN1 dn []) --B.concat $ L.toChunks $ encodeDN dn
-- Encode a list of distinguished names.
encodeCertAuthorities certAuths = do
enc <- mapM encodeCA certAuths
let totLength = sum $ map (((+) 2) . B.length) enc
putWord16 (fromIntegral totLength)
mapM_ (\ b -> putWord16 (fromIntegral (B.length b)) >> putBytes b) enc
encodeHandshakeContent (CertVerify mbHashSig (CertVerifyData c)) = do
-- TLS 1.2 prepends the hash and signature algorithms to the
-- signature.
case mbHashSig of
Nothing -> return ()
Just (h, s) -> putWord16 $ (fromIntegral $ valOfType h) * 256 + (fromIntegral $ valOfType s)
putWord16 (fromIntegral $ B.length c)
putBytes c
encodeHandshakeContent (Finished opaque) = putBytes opaque
encodeHandshakeContent (HsNextProtocolNegotiation protocol) = do
putOpaque8 protocol
putOpaque8 $ B.replicate paddingLen 0
where paddingLen = 32 - ((B.length protocol + 2) `mod` 32)
{- FIXME make sure it return error if not 32 available -}
getRandom32 :: Get Bytes
getRandom32 = getBytes 32
getServerRandom32 :: Get ServerRandom
getServerRandom32 = ServerRandom <$> getRandom32
getClientRandom32 :: Get ClientRandom
getClientRandom32 = ClientRandom <$> getRandom32
putRandom32 :: Bytes -> Put
putRandom32 = putBytes
putClientRandom32 :: ClientRandom -> Put
putClientRandom32 (ClientRandom r) = putRandom32 r
putServerRandom32 :: ServerRandom -> Put
putServerRandom32 (ServerRandom r) = putRandom32 r
getSession :: Get Session
getSession = do
len8 <- getWord8
case fromIntegral len8 of
0 -> return $ Session Nothing
len -> Session . Just <$> getBytes len
putSession :: Session -> Put
putSession (Session Nothing) = putWord8 0
putSession (Session (Just s)) = putOpaque8 s
getExtensions :: Int -> Get [ExtensionRaw]
getExtensions 0 = return []
getExtensions len = do
extty <- getWord16
extdatalen <- getWord16
extdata <- getBytes $ fromIntegral extdatalen
extxs <- getExtensions (len - fromIntegral extdatalen - 4)
return $ (extty, extdata) : extxs
putExtension :: ExtensionRaw -> Put
putExtension (ty, l) = putWord16 ty >> putOpaque16 l
putExtensions :: [ExtensionRaw] -> Put
putExtensions [] = return ()
putExtensions es = putOpaque16 (runPut $ mapM_ putExtension es)
{-
- decode and encode ALERT
-}
decodeChangeCipherSpec :: ByteString -> Either TLSError ()
decodeChangeCipherSpec = runGetErr "changecipherspec" $ do
x <- getWord8
when (x /= 1) (fail "unknown change cipher spec content")
encodeChangeCipherSpec :: ByteString
encodeChangeCipherSpec = runPut (putWord8 1)
-- rsa pre master secret
decodePreMasterSecret :: Bytes -> Either TLSError (Version, Bytes)
decodePreMasterSecret = runGetErr "pre-master-secret" $ do
liftM2 (,) getVersion (getBytes 46)
encodePreMasterSecret :: Version -> Bytes -> Bytes
encodePreMasterSecret version bytes = runPut (putVersion version >> putBytes bytes)
{-
- generate things for packet content
-}
type PRF = Bytes -> Bytes -> Int -> Bytes
generateMasterSecret_SSL :: Bytes -> ClientRandom -> ServerRandom -> Bytes
generateMasterSecret_SSL premasterSecret (ClientRandom c) (ServerRandom s) =
B.concat $ map (computeMD5) ["A","BB","CCC"]
where
computeMD5 label = MD5.hash $ B.concat [ premasterSecret, computeSHA1 label ]
computeSHA1 label = SHA1.hash $ B.concat [ label, premasterSecret, c, s ]
generateMasterSecret_TLS :: PRF -> Bytes -> ClientRandom -> ServerRandom -> Bytes
generateMasterSecret_TLS prf premasterSecret (ClientRandom c) (ServerRandom s) =
prf premasterSecret seed 48
where
seed = B.concat [ "master secret", c, s ]
generateMasterSecret :: Version -> Bytes -> ClientRandom -> ServerRandom -> Bytes
generateMasterSecret SSL2 = generateMasterSecret_SSL
generateMasterSecret SSL3 = generateMasterSecret_SSL
generateMasterSecret TLS10 = generateMasterSecret_TLS prf_MD5SHA1
generateMasterSecret TLS11 = generateMasterSecret_TLS prf_MD5SHA1
generateMasterSecret TLS12 = generateMasterSecret_TLS prf_SHA256
generateKeyBlock_TLS :: PRF -> ClientRandom -> ServerRandom -> Bytes -> Int -> Bytes
generateKeyBlock_TLS prf (ClientRandom c) (ServerRandom s) mastersecret kbsize =
prf mastersecret seed kbsize where seed = B.concat [ "key expansion", s, c ]
generateKeyBlock_SSL :: ClientRandom -> ServerRandom -> Bytes -> Int -> Bytes
generateKeyBlock_SSL (ClientRandom c) (ServerRandom s) mastersecret kbsize =
B.concat $ map computeMD5 $ take ((kbsize `div` 16) + 1) labels
where
labels = [ uncurry BC.replicate x | x <- zip [1..] ['A'..'Z'] ]
computeMD5 label = MD5.hash $ B.concat [ mastersecret, computeSHA1 label ]
computeSHA1 label = SHA1.hash $ B.concat [ label, mastersecret, s, c ]
generateKeyBlock :: Version -> ClientRandom -> ServerRandom -> Bytes -> Int -> Bytes
generateKeyBlock SSL2 = generateKeyBlock_SSL
generateKeyBlock SSL3 = generateKeyBlock_SSL
generateKeyBlock TLS10 = generateKeyBlock_TLS prf_MD5SHA1
generateKeyBlock TLS11 = generateKeyBlock_TLS prf_MD5SHA1
generateKeyBlock TLS12 = generateKeyBlock_TLS prf_SHA256
generateFinished_TLS :: PRF -> Bytes -> Bytes -> HashCtx -> Bytes
generateFinished_TLS prf label mastersecret hashctx = prf mastersecret seed 12
where
seed = B.concat [ label, hashFinal hashctx ]
generateFinished_SSL :: Bytes -> Bytes -> HashCtx -> Bytes
generateFinished_SSL sender mastersecret hashctx = B.concat [md5hash, sha1hash]
where
md5hash = MD5.hash $ B.concat [ mastersecret, pad2, md5left ]
sha1hash = SHA1.hash $ B.concat [ mastersecret, B.take 40 pad2, sha1left ]
lefthash = hashFinal $ flip hashUpdateSSL (pad1, B.take 40 pad1)
$ foldl hashUpdate hashctx [sender,mastersecret]
(md5left,sha1left) = B.splitAt 16 lefthash
pad2 = B.replicate 48 0x5c
pad1 = B.replicate 48 0x36
generateClientFinished :: Version -> Bytes -> HashCtx -> Bytes
generateClientFinished ver
| ver < TLS10 = generateFinished_SSL "CLNT"
| ver < TLS12 = generateFinished_TLS prf_MD5SHA1 "client finished"
| otherwise = generateFinished_TLS prf_SHA256 "client finished"
generateServerFinished :: Version -> Bytes -> HashCtx -> Bytes
generateServerFinished ver
| ver < TLS10 = generateFinished_SSL "SRVR"
| ver < TLS12 = generateFinished_TLS prf_MD5SHA1 "server finished"
| otherwise = generateFinished_TLS prf_SHA256 "server finished"
generateCertificateVerify_SSL :: Bytes -> HashCtx -> Bytes
generateCertificateVerify_SSL = generateFinished_SSL ""