{-| Module : Hookup Description : Network connections generalized over TLS and SOCKS Copyright : (c) Eric Mertens, 2016 License : ISC Maintainer : emertens@gmail.com This module provides a uniform interface to network connections with optional support for TLS and SOCKS. This library is careful to support both IPv4 and IPv6. It will attempt to all of the addresses that a domain name resolves to until one the first successful connection. Use 'connect' and 'close' to establish and close network connections. Use 'recv', 'recvLine', and 'send' to receive and transmit data on an open network connection. TLS and SOCKS parameters can be provided. When both are provided a connection will first be established to the SOCKS server and then the TLS connection will be established through that proxy server. This is most useful when connecting through a dynamic port forward of an SSH client via the @-D@ flag. -} module Hookup ( -- * Connections Connection, connect, connectWithSocket, close, -- * Reading and writing data recv, recvLine, send, putBuf, -- * Configuration ConnectionParams(..), SocksParams(..), TlsParams(..), defaultFamily, defaultTlsParams, -- * Errors ConnectionFailure(..), CommandReply(..) -- * SSL Information , getPeerCertificate , getPeerCertFingerprintSha1 , getPeerCertFingerprintSha256 , getPeerCertFingerprintSha512 , getPeerPubkeyFingerprintSha1 , getPeerPubkeyFingerprintSha256 , getPeerPubkeyFingerprintSha512 ) where import Control.Concurrent import Control.Exception import Control.Monad import System.IO.Error (isDoesNotExistError, ioeGetErrorString) import Data.ByteString (ByteString) import qualified Data.ByteString as B import qualified Data.ByteString.Char8 as B8 import Data.Foldable import Data.List (intercalate) import Network.Socket (Socket, AddrInfo, PortNumber, HostName, Family) import qualified Network.Socket as Socket import qualified Network.Socket.ByteString as SocketB import OpenSSL.Session (SSL, SSLContext) import qualified OpenSSL as SSL import qualified OpenSSL.Session as SSL import OpenSSL.X509.SystemStore import OpenSSL.X509 (X509) import qualified OpenSSL.X509 as X509 import qualified OpenSSL.PEM as PEM import qualified OpenSSL.EVP.Digest as Digest import Data.Attoparsec.ByteString (Parser) import qualified Data.Attoparsec.ByteString as Parser import Hookup.OpenSSL (installVerification, getPubKeyDer) import Hookup.Socks5 -- | Parameters for 'connect'. -- -- Common defaults for fields: 'defaultFamily', 'defaultTlsParams' -- -- The address family can be specified in order to force only -- IPv4 or IPv6 to be used. The default behavior is to support both. -- It can be useful to specify exactly one of these in the case that -- the other is misconfigured and a hostname is resolving to both. -- -- When a 'SocksParams' is provided the connection will be established -- using a SOCKS (version 5) proxy. -- -- When a 'TlsParams' is provided the connection negotiate TLS at connect -- time in order to protect the stream. data ConnectionParams = ConnectionParams { cpFamily :: Family -- ^ IP Protocol family (default 'AF_UNSPEC') , cpHost :: HostName -- ^ Destination host , cpPort :: PortNumber -- ^ Destination TCP port , cpSocks :: Maybe SocksParams -- ^ Optional SOCKS parameters , cpTls :: Maybe TlsParams -- ^ Optional TLS parameters } -- | SOCKS connection parameters data SocksParams = SocksParams { spHost :: HostName -- ^ SOCKS server host , spPort :: PortNumber -- ^ SOCKS server port } -- | TLS connection parameters. These parameters are passed to -- OpenSSL when making a secure connection. data TlsParams = TlsParams { tpClientCertificate :: Maybe FilePath -- ^ Path to client certificate , tpClientPrivateKey :: Maybe FilePath -- ^ Path to client private key , tpServerCertificate :: Maybe FilePath -- ^ Path to CA certificate bundle , tpCipherSuite :: String -- ^ OpenSSL cipher suite name (e.g. @\"HIGH\"@) , tpInsecure :: Bool -- ^ Disables certificate checking when 'True' } -- | Type for errors that can be thrown by this package. data ConnectionFailure -- | Failure during 'getAddrInfo' resolving remote host = HostnameResolutionFailure HostName String -- | Failure during 'connect' to remote host | ConnectionFailure [IOError] -- | Failure during 'recvLine' | LineTooLong -- | Incomplete line during 'recvLine' | LineTruncated -- | Socks command rejected by server by given reply code | SocksError CommandReply -- | Socks authentication method was not accepted | SocksAuthenticationError -- | Socks server sent an invalid message or no message. | SocksProtocolError -- | Domain name was too long for SOCKS protocol | SocksBadDomainName deriving Show -- | 'displayException' implemented for prettier messages instance Exception ConnectionFailure where displayException LineTruncated = "connection closed while reading line" displayException LineTooLong = "line length exceeded maximum" displayException (ConnectionFailure xs) = "connection attempt failed due to: " ++ intercalate ", " (map displayException xs) displayException (HostnameResolutionFailure h s) = "hostname resolution failed (" ++ h ++ "): " ++ s displayException SocksAuthenticationError = "SOCKS authentication method rejected" displayException SocksProtocolError = "SOCKS server protocol error" displayException SocksBadDomainName = "SOCKS domain name length limit exceeded" displayException (SocksError reply) = "SOCKS command rejected: " ++ case reply of Succeeded -> "succeeded" GeneralFailure -> "general SOCKS server failure" NotAllowed -> "connection not allowed by ruleset" NetUnreachable -> "network unreachable" HostUnreachable -> "host unreachable" ConnectionRefused -> "connection refused" TTLExpired -> "TTL expired" CmdNotSupported -> "command not supported" AddrNotSupported -> "address type not supported" CommandReply n -> "unknown reply " ++ show n -- | Default 'Family' value is unspecified and allows both INET and INET6. defaultFamily :: Socket.Family defaultFamily = Socket.AF_UNSPEC -- | Default values for TLS that use no client certificates, use -- system CA root, @\"HIGH\"@ cipher suite, and which validate hostnames. defaultTlsParams :: TlsParams defaultTlsParams = TlsParams { tpClientCertificate = Nothing , tpClientPrivateKey = Nothing , tpServerCertificate = Nothing -- use system provided CAs , tpCipherSuite = "HIGH" , tpInsecure = False } ------------------------------------------------------------------------ -- Opening sockets ------------------------------------------------------------------------ -- | Open a socket using the given parameters either directly or -- via a SOCKS server. openSocket :: ConnectionParams -> IO Socket openSocket params = case cpSocks params of Nothing -> openSocket' (cpFamily params) (cpHost params) (cpPort params) Just sp -> do sock <- openSocket' (cpFamily params) (spHost sp) (spPort sp) (sock <$ socksConnect sock (cpHost params) (cpPort params)) `onException` Socket.close sock netParse :: Show a => Socket -> Parser a -> IO a netParse sock parser = do -- receiving 1 byte at a time is not efficient, but these messages -- are very short and we don't want to read any more from the socket -- than is necessary result <- Parser.parseWith (SocketB.recv sock 1) parser B.empty case result of Parser.Done i x | B.null i -> return x _ -> throwIO SocksProtocolError socksConnect :: Socket -> HostName -> PortNumber -> IO () socksConnect sock host port = do SocketB.sendAll sock $ buildClientHello ClientHello { cHelloMethods = [AuthNoAuthenticationRequired] } validateHello =<< netParse sock parseServerHello let dnBytes = B8.pack host unless (B.length dnBytes < 256) (throwIO SocksBadDomainName) SocketB.sendAll sock $ buildRequest Request { reqCommand = Connect , reqAddress = Address (DomainName dnBytes) port } validateResponse =<< netParse sock parseResponse validateHello :: ServerHello -> IO () validateHello hello = unless (sHelloMethod hello == AuthNoAuthenticationRequired) (throwIO SocksAuthenticationError) validateResponse :: Response -> IO () validateResponse response = unless (rspReply response == Succeeded ) (throwIO (SocksError (rspReply response))) openSocket' :: Family -> HostName -> PortNumber -> IO Socket openSocket' family h p = do let hints = Socket.defaultHints { Socket.addrFamily = family , Socket.addrSocketType = Socket.Stream , Socket.addrFlags = [Socket.AI_ADDRCONFIG ,Socket.AI_NUMERICSERV] } res <- try (Socket.getAddrInfo (Just hints) (Just h) (Just (show p))) case res of Right ais -> attemptConnections [] ais Left ioe | isDoesNotExistError ioe -> throwIO (HostnameResolutionFailure h (ioeGetErrorString ioe)) | otherwise -> throwIO ioe -- unexpected -- | Try establishing a connection to the services indicated by -- a given list of 'AddrInfo' values. Either return a socket that -- has successfully connected to one of the candidate 'AddrInfo's -- or throw a 'ConnectionFailure' exception will all of the -- encountered errors. attemptConnections :: [IOError] {- ^ accumulated errors -} -> [Socket.AddrInfo] {- ^ candidate AddrInfos -} -> IO Socket {- ^ connected socket -} attemptConnections exs [] = throwIO (ConnectionFailure exs) attemptConnections exs (ai:ais) = do res <- try (connectToAddrInfo ai) case res of Left ex -> attemptConnections (ex:exs) ais Right s -> return s -- | Create a socket and connect to the service identified -- by the given 'AddrInfo' and return the connected socket. connectToAddrInfo :: AddrInfo -> IO Socket connectToAddrInfo info = bracketOnError (socket' info) Socket.close $ \s -> s <$ Socket.connect s (Socket.addrAddress info) -- | Open a 'Socket' using the parameters from an 'AddrInfo' socket' :: AddrInfo -> IO Socket socket' ai = Socket.socket (Socket.addrFamily ai) (Socket.addrSocketType ai) (Socket.addrProtocol ai) ------------------------------------------------------------------------ -- Generalization of Socket ------------------------------------------------------------------------ data NetworkHandle = SSL SSL | Socket Socket openNetworkHandle :: ConnectionParams {- ^ parameters -} -> IO Socket {- ^ socket creation action -} -> IO NetworkHandle {- ^ open network handle -} openNetworkHandle params mkSocket = case cpTls params of Nothing -> Socket <$> mkSocket Just tls -> SSL <$> startTls tls (cpHost params) mkSocket closeNetworkHandle :: NetworkHandle -> IO () closeNetworkHandle (Socket s) = Socket.close s closeNetworkHandle (SSL s) = do SSL.shutdown s SSL.Unidirectional traverse_ Socket.close (SSL.sslSocket s) networkSend :: NetworkHandle -> ByteString -> IO () networkSend (Socket s) = SocketB.sendAll s networkSend (SSL s) = SSL.write s networkRecv :: NetworkHandle -> Int -> IO ByteString networkRecv (Socket s) = SocketB.recv s networkRecv (SSL s) = SSL.read s ------------------------------------------------------------------------ -- Sockets with a receive buffer ------------------------------------------------------------------------ -- | A connection to a network service along with its read buffer -- used for line-oriented protocols. The connection could be a plain -- network connection, SOCKS connected, or TLS. data Connection = Connection (MVar ByteString) NetworkHandle -- | Open network connection to TCP service specified by -- the given parameters. -- -- The resulting connection MUST be closed with 'close' to avoid leaking -- resources. -- -- Throws 'IOError', 'SocksError', 'SSL.ProtocolError', 'ConnectionFailure' connect :: ConnectionParams {- ^ parameters -} -> IO Connection {- ^ open connection -} connect params = do h <- openNetworkHandle params (openSocket params) b <- newMVar B.empty return (Connection b h) -- | Create a new 'Connection' using an already connected socket. -- This will attempt to start TLS if configured but will ignore -- any SOCKS server settings as it is assumed that the socket -- is already actively connected to the intended service. -- -- Throws 'SSL.ProtocolError' connectWithSocket :: ConnectionParams {- ^ parameters -} -> Socket {- ^ connected socket -} -> IO Connection {- ^ open connection -} connectWithSocket params sock = do h <- openNetworkHandle params (return sock) b <- newMVar B.empty return (Connection b h) -- | Close network connection. close :: Connection {- ^ open connection -} -> IO () close (Connection _ h) = closeNetworkHandle h -- | Receive the next chunk from the stream. This operation will first -- return the buffer if it contains a non-empty chunk. Otherwise it will -- request up to the requested number of bytes from the stream. -- -- Throws: 'IOError', 'SSL.ConnectionAbruptlyTerminated', 'SSL.ProtocolError' recv :: Connection {- ^ open connection -} -> Int {- ^ maximum underlying recv size -} -> IO ByteString {- ^ next chunk from stream -} recv (Connection buf h) n = do bufChunk <- swapMVar buf B.empty if B.null bufChunk then networkRecv h n else return bufChunk -- | Receive a line from the network connection. Both -- @"\\r\\n"@ and @"\\n"@ are recognized. -- -- Returning 'Nothing' means that the peer has closed its half of -- the connection. -- -- Unterminated lines will raise a 'LineTruncated' exception. This -- can happen if the peer transmits some data and closes its end -- without transmitting a line terminator. -- -- Throws: 'SSL.ConnectionAbruptlyTerminated', 'SSL.ProtocolError', 'ConnectionFailure', 'IOError' recvLine :: Connection {- ^ open connection -} -> Int {- ^ maximum line length -} -> IO (Maybe ByteString) {- ^ next line or end-of-stream -} recvLine (Connection buf h) n = modifyMVar buf $ \bs -> go (B.length bs) bs [] where -- bsn: cached length of concatenation of (bs:bss) -- bs : most recent chunk -- bss: other chunks ordered from most to least recent go bsn bs bss = case B8.elemIndex '\n' bs of Just i -> return (B.tail b, -- tail drops newline Just (cleanEnd (B.concat (reverse (a:bss))))) where (a,b) = B.splitAt i bs Nothing -> do when (bsn >= n) (throwIO LineTooLong) more <- networkRecv h n if B.null more -- connection closed then if bsn == 0 then return (B.empty, Nothing) else throwIO LineTruncated else go (bsn + B.length more) more (bs:bss) -- | Push a 'ByteString' onto the buffer so that it will be the first -- bytes to be read on the next receive operation. This could perhaps -- be useful for putting the unused portion of a 'recv' back into the -- buffer for future 'recvLine' or 'recv' operations. putBuf :: Connection {- ^ connection -} -> ByteString {- ^ new head of buffer -} -> IO () putBuf (Connection buf h) bs = modifyMVar_ buf (\old -> return $! B.append bs old) -- | Remove the trailing @'\\r'@ if one is found. cleanEnd :: ByteString -> ByteString cleanEnd bs | B.null bs || B8.last bs /= '\r' = bs | otherwise = B.init bs -- | Send bytes on the network connection. This ensures the whole chunk is -- transmitted, which might take multiple underlying sends. -- -- Throws: 'IOError', 'SSL.ProtocolError' send :: Connection {- ^ open connection -} -> ByteString {- ^ chunk -} -> IO () send (Connection _ h) = networkSend h ------------------------------------------------------------------------ -- | Initiate a TLS session on the given socket destined for -- the given hostname. When successful an active TLS connection -- is returned with certificate verification successful when -- requested. This function requires that the TLSParams component -- of 'ConnectionParams' is set. startTls :: TlsParams {- ^ connection params -} -> String {- ^ hostname -} -> IO Socket {- ^ socket creation action -} -> IO SSL {- ^ connected TLS -} startTls tp hostname mkSocket = SSL.withOpenSSL $ do ctx <- SSL.context -- configure context SSL.contextSetCiphers ctx (tpCipherSuite tp) installVerification ctx hostname SSL.contextSetVerificationMode ctx (verificationMode (tpInsecure tp)) SSL.contextAddOption ctx SSL.SSL_OP_ALL SSL.contextRemoveOption ctx SSL.SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS -- configure certificates setupCaCertificates ctx (tpServerCertificate tp) traverse_ (setupCertificate ctx) (tpClientCertificate tp) traverse_ (setupPrivateKey ctx) (tpClientPrivateKey tp) -- add socket to context -- creation of the socket is delayed until this point to avoid -- leaking the file descriptor in the cases of exceptions above. ssl <- SSL.connection ctx =<< mkSocket -- configure hostname used for certificate validation SSL.setTlsextHostName ssl hostname SSL.connect ssl return ssl setupCaCertificates :: SSLContext -> Maybe FilePath -> IO () setupCaCertificates ctx mbPath = case mbPath of Nothing -> contextLoadSystemCerts ctx Just path -> SSL.contextSetCAFile ctx path setupCertificate :: SSLContext -> FilePath -> IO () setupCertificate ctx path = SSL.contextSetCertificate ctx =<< PEM.readX509 -- EX =<< readFile path setupPrivateKey :: SSLContext -> FilePath -> IO () setupPrivateKey ctx path = do str <- readFile path -- EX key <- PEM.readPrivateKey str PEM.PwNone -- TODO: add password support SSL.contextSetPrivateKey ctx key verificationMode :: Bool {- ^ insecure -} -> SSL.VerificationMode verificationMode insecure | insecure = SSL.VerifyNone | otherwise = SSL.VerifyPeer { SSL.vpFailIfNoPeerCert = True , SSL.vpClientOnce = True , SSL.vpCallback = Nothing } -- | Get peer certificate if one exists. getPeerCertificate :: Connection -> IO (Maybe X509.X509) getPeerCertificate (Connection _ h) = case h of Socket{} -> return Nothing SSL ssl -> SSL.getPeerCertificate ssl getPeerCertFingerprintSha1 :: Connection -> IO (Maybe ByteString) getPeerCertFingerprintSha1 = getPeerCertFingerprint "sha1" getPeerCertFingerprintSha256 :: Connection -> IO (Maybe ByteString) getPeerCertFingerprintSha256 = getPeerCertFingerprint "sha256" getPeerCertFingerprintSha512 :: Connection -> IO (Maybe ByteString) getPeerCertFingerprintSha512 = getPeerCertFingerprint "sha512" getPeerCertFingerprint :: String -> Connection -> IO (Maybe ByteString) getPeerCertFingerprint name h = do mb <- getPeerCertificate h case mb of Nothing -> return Nothing Just x509 -> do der <- X509.writeDerX509 x509 mbdigest <- Digest.getDigestByName name case mbdigest of Nothing -> return Nothing Just digest -> return $! Just $! Digest.digestLBS digest der getPeerPubkeyFingerprintSha1 :: Connection -> IO (Maybe ByteString) getPeerPubkeyFingerprintSha1 = getPeerPubkeyFingerprint "sha1" getPeerPubkeyFingerprintSha256 :: Connection -> IO (Maybe ByteString) getPeerPubkeyFingerprintSha256 = getPeerPubkeyFingerprint "sha256" getPeerPubkeyFingerprintSha512 :: Connection -> IO (Maybe ByteString) getPeerPubkeyFingerprintSha512 = getPeerPubkeyFingerprint "sha512" getPeerPubkeyFingerprint :: String -> Connection -> IO (Maybe ByteString) getPeerPubkeyFingerprint name h = do mb <- getPeerCertificate h case mb of Nothing -> return Nothing Just x509 -> do der <- getPubKeyDer x509 mbdigest <- Digest.getDigestByName name case mbdigest of Nothing -> return Nothing Just digest -> return $! Just $! Digest.digestBS digest der