diff options
Diffstat (limited to 'src/Channel.hs')
| -rw-r--r-- | src/Channel.hs | 128 |
1 files changed, 61 insertions, 67 deletions
diff --git a/src/Channel.hs b/src/Channel.hs index b273392..a1773bd 100644 --- a/src/Channel.hs +++ b/src/Channel.hs @@ -15,17 +15,14 @@ import Control.Concurrent.MVar import Control.Monad import Control.Monad.Except -import Crypto.Cipher.AES -import Crypto.Cipher.Types +import Crypto.Cipher.ChaChaPoly1305 import Crypto.Error import Data.Binary -import Data.ByteArray (ByteArray, Bytes, ScrubbedBytes, append, convert) +import Data.ByteArray (ByteArray, Bytes, ScrubbedBytes, convert) import Data.ByteArray qualified as BA -import Data.ByteString qualified as B import Data.ByteString.Lazy qualified as BL import Data.List -import Data.Text qualified as T import Identity import PubKey @@ -36,7 +33,8 @@ data Channel = Channel , chKey :: ScrubbedBytes , chNonceFixedOur :: Bytes , chNonceFixedPeer :: Bytes - , chNonceCounter :: MVar Word64 + , chCounterNextOut :: MVar Word64 + , chCounterNextIn :: MVar Word64 } type ChannelRequest = Signed ChannelRequestData @@ -58,12 +56,9 @@ data ChannelAcceptData = ChannelAccept instance Storable ChannelRequestData where store' cr = storeRec $ do mapM_ (storeRef "peer") $ crPeers cr - storeText "enc" $ T.pack "aes-128-gcm" storeRef "key" $ crKey cr load' = loadRec $ do - enc <- loadText "enc" - guard $ enc == "aes-128-gcm" ChannelRequest <$> loadRefs "peer" <*> loadRef "key" @@ -71,17 +66,17 @@ instance Storable ChannelRequestData where instance Storable ChannelAcceptData where store' ca = storeRec $ do storeRef "req" $ caRequest ca - storeText "enc" $ T.pack "aes-128-gcm" storeRef "key" $ caKey ca load' = loadRec $ do - enc <- loadText "enc" - guard $ enc == "aes-128-gcm" ChannelAccept <$> loadRef "req" <*> loadRef "key" +keySize :: Int +keySize = 32 + createChannelRequest :: (MonadIO m) => Storage -> UnifiedIdentity -> UnifiedIdentity -> m (Stored ChannelRequest) createChannelRequest st self peer = liftIO $ do (_, xpublic) <- generateKeys st @@ -101,30 +96,23 @@ acceptChannelRequest self peer req = do throwError $ "channel requent not signed by peer" let st = storedStorage req - ksize <- case cipherKeySize (undefined :: AES128) of - KeySizeFixed s -> return s - _ -> throwError "expecting fixed key size" liftIO $ do (xsecret, xpublic) <- generateKeys st Just skey <- loadKey $ idKeyMessage self acc <- wrappedStore st =<< sign skey =<< wrappedStore st ChannelAccept { caRequest = req, caKey = xpublic } - counter <- newMVar 0 - return $ (acc,) $ Channel - { chPeers = crPeers $ fromStored $ signedData $ fromStored req - , chKey = BA.take ksize $ dhSecret xsecret $ + let chPeers = crPeers $ fromStored $ signedData $ fromStored req + chKey = BA.take keySize $ dhSecret xsecret $ fromStored $ crKey $ fromStored $ signedData $ fromStored req - , chNonceFixedOur = BA.pack [ 2, 0, 0, 0, 0, 0 ] - , chNonceFixedPeer = BA.pack [ 1, 0, 0, 0, 0, 0 ] - , chNonceCounter = counter - } + chNonceFixedOur = BA.pack [ 2, 0, 0, 0 ] + chNonceFixedPeer = BA.pack [ 1, 0, 0, 0 ] + chCounterNextOut <- newMVar 0 + chCounterNextIn <- newMVar 0 + + return (acc, Channel {..}) acceptedChannel :: (MonadIO m, MonadError String m) => UnifiedIdentity -> UnifiedIdentity -> Stored ChannelAccept -> m Channel acceptedChannel self peer acc = do let req = caRequest $ fromStored $ signedData $ fromStored acc - ksize <- case cipherKeySize (undefined :: AES128) of - KeySizeFixed s -> return s - _ -> throwError "expecting fixed key size" - case sequence $ map validateIdentity $ crPeers $ fromStored $ signedData $ fromStored req of Nothing -> throwError $ "invalid peers in channel accept" Just peers -> do @@ -140,44 +128,50 @@ acceptedChannel self peer acc = do xsecret <- liftIO (loadKey $ crKey $ fromStored $ signedData $ fromStored req) >>= \case Just key -> return key Nothing -> throwError $ "secret key not found" - counter <- liftIO $ newMVar 0 - return $ Channel - { chPeers = crPeers $ fromStored $ signedData $ fromStored req - , chKey = BA.take ksize $ dhSecret xsecret $ + let chPeers = crPeers $ fromStored $ signedData $ fromStored req + chKey = BA.take keySize $ dhSecret xsecret $ fromStored $ caKey $ fromStored $ signedData $ fromStored acc - , chNonceFixedOur = BA.pack [ 1, 0, 0, 0, 0, 0 ] - , chNonceFixedPeer = BA.pack [ 2, 0, 0, 0, 0, 0 ] - , chNonceCounter = counter - } - - -channelEncrypt :: (ByteArray ba, MonadIO m, MonadError String m) => Channel -> ba -> m ba -channelEncrypt ch plain = do - cipher <- case cipherInit $ chKey ch of - CryptoPassed (cipher :: AES128) -> return cipher - _ -> throwError "failed to init AES128 cipher" - let bsize = blockSize cipher - count <- liftIO $ modifyMVar (chNonceCounter ch) $ \c -> return (c + 1, c) - let cbytes = convert $ BL.toStrict $ BL.drop 2 $ encode count - iv = chNonceFixedOur ch `append` cbytes - aead <- case aeadInit AEAD_GCM cipher iv of - CryptoPassed aead -> return aead - _ -> throwError "failed to init AEAD_GCM" - let (tag, ctext) = aeadSimpleEncrypt aead B.empty plain bsize - return $ BA.concat [ BA.pack [ 0, 0 ], convert cbytes, ctext, convert tag ] - -channelDecrypt :: (ByteArray ba, MonadError String m) => Channel -> ba -> m ba -channelDecrypt ch body = do - cipher <- case cipherInit $ chKey ch of - CryptoPassed (cipher :: AES128) -> return cipher - _ -> throwError "failed to init AES128 cipher" - let bsize = blockSize cipher - (cbytes, body') = BA.splitAt 8 body - iv = chNonceFixedPeer ch `append` convert (BA.drop 2 cbytes) - (ctext, tag) = BA.splitAt (BA.length body' - bsize) body' - aead <- case aeadInit AEAD_GCM cipher iv of - CryptoPassed aead -> return aead - _ -> throwError "failed to init AEAD_GCM" - case aeadSimpleDecrypt aead B.empty ctext (AuthTag $ convert tag) of - Just plain -> return plain - Nothing -> throwError "failed to decrypt data" + chNonceFixedOur = BA.pack [ 1, 0, 0, 0 ] + chNonceFixedPeer = BA.pack [ 2, 0, 0, 0 ] + chCounterNextOut <- liftIO $ newMVar 0 + chCounterNextIn <- liftIO $ newMVar 0 + + return Channel {..} + + +channelEncrypt :: (ByteArray ba, MonadIO m, MonadError String m) => Channel -> ba -> m (ba, Word64) +channelEncrypt Channel {..} plain = do + count <- liftIO $ modifyMVar chCounterNextOut $ \c -> return (c + 1, c) + let cbytes = convert $ BL.toStrict $ encode count + nonce = nonce8 chNonceFixedOur cbytes + state <- case initialize chKey =<< nonce of + CryptoPassed state -> return state + CryptoFailed err -> throwError $ "failed to init chacha-poly1305 cipher: " <> show err + + let (ctext, state') = encrypt plain state + tag = finalize state' + return (BA.concat [ convert $ BA.drop 7 cbytes, ctext, convert tag ], count) + +channelDecrypt :: (ByteArray ba, MonadIO m, MonadError String m) => Channel -> ba -> m (ba, Word64) +channelDecrypt Channel {..} body = do + when (BA.length body < 17) $ do + throwError $ "invalid encrypted data length" + + expectedCount <- liftIO $ readMVar chCounterNextIn + let countByte = body `BA.index` 0 + body' = BA.dropView body 1 + guessedCount = expectedCount - 128 + fromIntegral (countByte - fromIntegral expectedCount + 128 :: Word8) + nonce = nonce8 chNonceFixedPeer $ convert $ BL.toStrict $ encode guessedCount + blen = BA.length body' - 16 + ctext = BA.takeView body' blen + tag = BA.dropView body' blen + state <- case initialize chKey =<< nonce of + CryptoPassed state -> return state + CryptoFailed err -> throwError $ "failed to init chacha-poly1305 cipher: " <> show err + + let (plain, state') = decrypt (convert ctext) state + when (not $ tag `BA.constEq` finalize state') $ do + throwError $ "tag validation falied" + + liftIO $ modifyMVar_ chCounterNextIn $ return . max (guessedCount + 1) + return (plain, guessedCount) |