# -*- test-case-name: twisted.protocols.test.test_tls,twisted.internet.test.test_tls,twisted.test.test_sslverify -*- # Copyright (c) Twisted Matrix Laboratories. # See LICENSE for details. """ Implementation of a TLS transport (L{ISSLTransport}) as an L{IProtocol} layered on top of any L{ITransport} implementation, based on U{OpenSSL}'s memory BIO features. L{TLSMemoryBIOFactory} is a L{WrappingFactory} which wraps protocols created by the factory it wraps with L{TLSMemoryBIOProtocol}. L{TLSMemoryBIOProtocol} intercedes between the underlying transport and the wrapped protocol to implement SSL and TLS. Typical usage of this module looks like this:: from twisted.protocols.tls import TLSMemoryBIOFactory from twisted.internet.protocol import ServerFactory from twisted.internet.ssl import PrivateCertificate from twisted.internet import reactor from someapplication import ApplicationProtocol serverFactory = ServerFactory() serverFactory.protocol = ApplicationProtocol certificate = PrivateCertificate.loadPEM(certPEMData) contextFactory = certificate.options() tlsFactory = TLSMemoryBIOFactory(contextFactory, False, serverFactory) reactor.listenTCP(12345, tlsFactory) reactor.run() This API offers somewhat more flexibility than L{twisted.internet.interfaces.IReactorSSL}; for example, a L{TLSMemoryBIOProtocol} instance can use another instance of L{TLSMemoryBIOProtocol} as its transport, yielding TLS over TLS - useful to implement onion routing. It can also be used to run TLS over unusual transports, such as UNIX sockets and stdio. """ from __future__ import division, absolute_import from OpenSSL.SSL import Error, ZeroReturnError, WantReadError from OpenSSL.SSL import TLSv1_METHOD, Context, Connection try: Connection(Context(TLSv1_METHOD), None) except TypeError as e: if str(e) != "argument must be an int, or have a fileno() method.": raise raise ImportError("twisted.protocols.tls requires pyOpenSSL 0.10 or newer.") from zope.interface import implementer, providedBy, directlyProvides from twisted.python.compat import unicode from twisted.python.failure import Failure from twisted.python import log from twisted.python.reflect import safe_str from twisted.internet.interfaces import ( ISystemHandle, ISSLTransport, IPushProducer, ILoggingContext, IOpenSSLServerConnectionCreator, IOpenSSLClientConnectionCreator, ) from twisted.internet.main import CONNECTION_LOST from twisted.internet.protocol import Protocol from twisted.internet.task import cooperate from twisted.protocols.policies import ProtocolWrapper, WrappingFactory @implementer(IPushProducer) class _PullToPush(object): """ An adapter that converts a non-streaming to a streaming producer. Because of limitations of the producer API, this adapter requires the cooperation of the consumer. When the consumer's C{registerProducer} is called with a non-streaming producer, it must wrap it with L{_PullToPush} and then call C{startStreaming} on the resulting object. When the consumer's C{unregisterProducer} is called, it must call C{stopStreaming} on the L{_PullToPush} instance. If the underlying producer throws an exception from C{resumeProducing}, the producer will be unregistered from the consumer. @ivar _producer: the underling non-streaming producer. @ivar _consumer: the consumer with which the underlying producer was registered. @ivar _finished: C{bool} indicating whether the producer has finished. @ivar _coopTask: the result of calling L{cooperate}, the task driving the streaming producer. """ _finished = False def __init__(self, pullProducer, consumer): self._producer = pullProducer self._consumer = consumer def _pull(self): """ A generator that calls C{resumeProducing} on the underlying producer forever. If C{resumeProducing} throws an exception, the producer is unregistered, which should result in streaming stopping. """ while True: try: self._producer.resumeProducing() except: log.err(None, "%s failed, producing will be stopped:" % (safe_str(self._producer),)) try: self._consumer.unregisterProducer() # The consumer should now call stopStreaming() on us, # thus stopping the streaming. except: # Since the consumer blew up, we may not have had # stopStreaming() called, so we just stop on our own: log.err(None, "%s failed to unregister producer:" % (safe_str(self._consumer),)) self._finished = True return yield None def startStreaming(self): """ This should be called by the consumer when the producer is registered. Start streaming data to the consumer. """ self._coopTask = cooperate(self._pull()) def stopStreaming(self): """ This should be called by the consumer when the producer is unregistered. Stop streaming data to the consumer. """ if self._finished: return self._finished = True self._coopTask.stop() # IPushProducer implementation: def pauseProducing(self): self._coopTask.pause() def resumeProducing(self): self._coopTask.resume() def stopProducing(self): self.stopStreaming() self._producer.stopProducing() @implementer(IPushProducer) class _ProducerMembrane(object): """ Stand-in for producer registered with a L{TLSMemoryBIOProtocol} transport. Ensures that producer pause/resume events from the undelying transport are coordinated with pause/resume events from the TLS layer. @ivar _producer: The application-layer producer. """ _producerPaused = False def __init__(self, producer): self._producer = producer def pauseProducing(self): """ C{pauseProducing} the underlying producer, if it's not paused. """ if self._producerPaused: return self._producerPaused = True self._producer.pauseProducing() def resumeProducing(self): """ C{resumeProducing} the underlying producer, if it's paused. """ if not self._producerPaused: return self._producerPaused = False self._producer.resumeProducing() def stopProducing(self): """ C{stopProducing} the underlying producer. There is only a single source for this event, so it's simply passed on. """ self._producer.stopProducing() @implementer(ISystemHandle, ISSLTransport) class TLSMemoryBIOProtocol(ProtocolWrapper): """ L{TLSMemoryBIOProtocol} is a protocol wrapper which uses OpenSSL via a memory BIO to encrypt bytes written to it before sending them on to the underlying transport and decrypts bytes received from the underlying transport before delivering them to the wrapped protocol. In addition to producer events from the underlying transport, the need to wait for reads before a write can proceed means the L{TLSMemoryBIOProtocol} may also want to pause a producer. Pause/resume events are therefore merged using the L{_ProducerMembrane} wrapper. Non-streaming (pull) producers are supported by wrapping them with L{_PullToPush}. @ivar _tlsConnection: The L{OpenSSL.SSL.Connection} instance which is encrypted and decrypting this connection. @ivar _lostTLSConnection: A flag indicating whether connection loss has already been dealt with (C{True}) or not (C{False}). TLS disconnection is distinct from the underlying connection being lost. @ivar _writeBlockedOnRead: A flag indicating whether further writing must wait for data to be received (C{True}) or not (C{False}). @ivar _appSendBuffer: A C{list} of C{str} of application-level (cleartext) data which is waiting for C{_writeBlockedOnRead} to be reset to C{False} so it can be passed to and perhaps accepted by C{_tlsConnection.send}. @ivar _connectWrapped: A flag indicating whether or not to call C{makeConnection} on the wrapped protocol. This is for the reactor's L{twisted.internet.interfaces.ITLSTransport.startTLS} implementation, since it has a protocol which it has already called C{makeConnection} on, and which has no interest in a new transport. See #3821. @ivar _handshakeDone: A flag indicating whether or not the handshake is known to have completed successfully (C{True}) or not (C{False}). This is used to control error reporting behavior. If the handshake has not completed, the underlying L{OpenSSL.SSL.Error} will be passed to the application's C{connectionLost} method. If it has completed, any unexpected L{OpenSSL.SSL.Error} will be turned into a L{ConnectionLost}. This is weird; however, it is simply an attempt at a faithful re-implementation of the behavior provided by L{twisted.internet.ssl}. @ivar _reason: If an unexpected L{OpenSSL.SSL.Error} occurs which causes the connection to be lost, it is saved here. If appropriate, this may be used as the reason passed to the application protocol's C{connectionLost} method. @ivar _producer: The current producer registered via C{registerProducer}, or C{None} if no producer has been registered or a previous one was unregistered. @ivar _aborted: C{abortConnection} has been called. No further data will be received to the wrapped protocol's C{dataReceived}. @type _aborted: L{bool} """ _reason = None _handshakeDone = False _lostTLSConnection = False _writeBlockedOnRead = False _producer = None _aborted = False def __init__(self, factory, wrappedProtocol, _connectWrapped=True): ProtocolWrapper.__init__(self, factory, wrappedProtocol) self._connectWrapped = _connectWrapped def getHandle(self): """ Return the L{OpenSSL.SSL.Connection} object being used to encrypt and decrypt this connection. This is done for the benefit of L{twisted.internet.ssl.Certificate}'s C{peerFromTransport} and C{hostFromTransport} methods only. A different system handle may be returned by future versions of this method. """ return self._tlsConnection def makeConnection(self, transport): """ Connect this wrapper to the given transport and initialize the necessary L{OpenSSL.SSL.Connection} with a memory BIO. """ self._tlsConnection = self.factory._createConnection(self) self._appSendBuffer = [] # Add interfaces provided by the transport we are wrapping: for interface in providedBy(transport): directlyProvides(self, interface) # Intentionally skip ProtocolWrapper.makeConnection - it might call # wrappedProtocol.makeConnection, which we want to make conditional. Protocol.makeConnection(self, transport) self.factory.registerProtocol(self) if self._connectWrapped: # Now that the TLS layer is initialized, notify the application of # the connection. ProtocolWrapper.makeConnection(self, transport) # Now that we ourselves have a transport (initialized by the # ProtocolWrapper.makeConnection call above), kick off the TLS # handshake. try: self._tlsConnection.do_handshake() except WantReadError: # This is the expected case - there's no data in the connection's # input buffer yet, so it won't be able to complete the whole # handshake now. If this is the speak-first side of the # connection, then some bytes will be in the send buffer now; flush # them. self._flushSendBIO() def _flushSendBIO(self): """ Read any bytes out of the send BIO and write them to the underlying transport. """ try: bytes = self._tlsConnection.bio_read(2 ** 15) except WantReadError: # There may be nothing in the send BIO right now. pass else: self.transport.write(bytes) def _flushReceiveBIO(self): """ Try to receive any application-level bytes which are now available because of a previous write into the receive BIO. This will take care of delivering any application-level bytes which are received to the protocol, as well as handling of the various exceptions which can come from trying to get such bytes. """ # Keep trying this until an error indicates we should stop or we # close the connection. Looping is necessary to make sure we # process all of the data which was put into the receive BIO, as # there is no guarantee that a single recv call will do it all. while not self._lostTLSConnection: try: bytes = self._tlsConnection.recv(2 ** 15) except WantReadError: # The newly received bytes might not have been enough to produce # any application data. break except ZeroReturnError: # TLS has shut down and no more TLS data will be received over # this connection. self._shutdownTLS() # Passing in None means the user protocol's connnectionLost # will get called with reason from underlying transport: self._tlsShutdownFinished(None) except Error as e: # Something went pretty wrong. For example, this might be a # handshake failure (because there were no shared ciphers, because # a certificate failed to verify, etc). TLS can no longer proceed. # Squash EOF in violation of protocol into ConnectionLost; we # create Failure before calling _flushSendBio so that no new # exception will get thrown in the interim. if e.args[0] == -1 and e.args[1] == 'Unexpected EOF': failure = Failure(CONNECTION_LOST) else: failure = Failure() self._flushSendBIO() self._tlsShutdownFinished(failure) else: # If we got application bytes, the handshake must be done by # now. Keep track of this to control error reporting later. self._handshakeDone = True if not self._aborted: ProtocolWrapper.dataReceived(self, bytes) # The received bytes might have generated a response which needs to be # sent now. For example, the handshake involves several round-trip # exchanges without ever producing application-bytes. self._flushSendBIO() def dataReceived(self, bytes): """ Deliver any received bytes to the receive BIO and then read and deliver to the application any application-level data which becomes available as a result of this. """ self._tlsConnection.bio_write(bytes) if self._writeBlockedOnRead: # A read just happened, so we might not be blocked anymore. Try to # flush all the pending application bytes. self._writeBlockedOnRead = False appSendBuffer = self._appSendBuffer self._appSendBuffer = [] for bytes in appSendBuffer: self._write(bytes) if (not self._writeBlockedOnRead and self.disconnecting and self.producer is None): self._shutdownTLS() if self._producer is not None: self._producer.resumeProducing() self._flushReceiveBIO() def _shutdownTLS(self): """ Initiate, or reply to, the shutdown handshake of the TLS layer. """ try: shutdownSuccess = self._tlsConnection.shutdown() except Error: # Mid-handshake, a call to shutdown() can result in a # WantWantReadError, or rather an SSL_ERR_WANT_READ; but pyOpenSSL # doesn't allow us to get at the error. See: # https://github.com/pyca/pyopenssl/issues/91 shutdownSuccess = False self._flushSendBIO() if shutdownSuccess: # Both sides have shutdown, so we can start closing lower-level # transport. This will also happen if we haven't started # negotiation at all yet, in which case shutdown succeeds # immediately. self.transport.loseConnection() def _tlsShutdownFinished(self, reason): """ Called when TLS connection has gone away; tell underlying transport to disconnect. """ if self._reason is None: self._reason = reason self._lostTLSConnection = True # Using loseConnection causes the application protocol's # connectionLost method to be invoked non-reentrantly, which is always # a nice feature. However, for error cases (reason != None) we might # want to use abortConnection when it becomes available. The # loseConnection call is basically tested by test_handshakeFailure. # At least one side will need to do it or the test never finishes. self.transport.loseConnection() def connectionLost(self, reason): """ Handle the possible repetition of calls to this method (due to either the underlying transport going away or due to an error at the TLS layer) and make sure the base implementation only gets invoked once. """ if not self._lostTLSConnection: # Tell the TLS connection that it's not going to get any more data # and give it a chance to finish reading. self._tlsConnection.bio_shutdown() self._flushReceiveBIO() self._lostTLSConnection = True reason = self._reason or reason self._reason = None ProtocolWrapper.connectionLost(self, reason) def loseConnection(self): """ Send a TLS close alert and close the underlying connection. """ if self.disconnecting: return self.disconnecting = True if not self._writeBlockedOnRead and self._producer is None: self._shutdownTLS() def abortConnection(self): """ Tear down TLS state so that if the connection is aborted mid-handshake we don't deliver any further data from the application. """ self._aborted = True self.disconnecting = True self._shutdownTLS() self.transport.abortConnection() def failVerification(self, reason): """ Abort the connection during connection setup, giving a reason that certificate verification failed. @param reason: The reason that the verification failed; reported to the application protocol's C{connectionLost} method. @type reason: L{Failure} """ self._reason = reason self.abortConnection() def write(self, bytes): """ Process the given application bytes and send any resulting TLS traffic which arrives in the send BIO. If C{loseConnection} was called, subsequent calls to C{write} will drop the bytes on the floor. """ if isinstance(bytes, unicode): raise TypeError("Must write bytes to a TLS transport, not unicode.") # Writes after loseConnection are not supported, unless a producer has # been registered, in which case writes can happen until the producer # is unregistered: if self.disconnecting and self._producer is None: return self._write(bytes) def _write(self, bytes): """ Process the given application bytes and send any resulting TLS traffic which arrives in the send BIO. This may be called by C{dataReceived} with bytes that were buffered before C{loseConnection} was called, which is why this function doesn't check for disconnection but accepts the bytes regardless. """ if self._lostTLSConnection: return # A TLS payload is 16kB max bufferSize = 2 ** 16 # How far into the input we've gotten so far alreadySent = 0 while alreadySent < len(bytes): toSend = bytes[alreadySent:alreadySent + bufferSize] try: sent = self._tlsConnection.send(toSend) except WantReadError: self._writeBlockedOnRead = True self._appSendBuffer.append(bytes[alreadySent:]) if self._producer is not None: self._producer.pauseProducing() break except Error: # Pretend TLS connection disconnected, which will trigger # disconnect of underlying transport. The error will be passed # to the application protocol's connectionLost method. The # other SSL implementation doesn't, but losing helpful # debugging information is a bad idea. self._tlsShutdownFinished(Failure()) break else: # If we sent some bytes, the handshake must be done. Keep # track of this to control error reporting behavior. self._handshakeDone = True self._flushSendBIO() alreadySent += sent def writeSequence(self, iovec): """ Write a sequence of application bytes by joining them into one string and passing them to L{write}. """ self.write(b"".join(iovec)) def getPeerCertificate(self): return self._tlsConnection.get_peer_certificate() def registerProducer(self, producer, streaming): # If we've already disconnected, nothing to do here: if self._lostTLSConnection: producer.stopProducing() return # If we received a non-streaming producer, wrap it so it becomes a # streaming producer: if not streaming: producer = streamingProducer = _PullToPush(producer, self) producer = _ProducerMembrane(producer) # This will raise an exception if a producer is already registered: self.transport.registerProducer(producer, True) self._producer = producer # If we received a non-streaming producer, we need to start the # streaming wrapper: if not streaming: streamingProducer.startStreaming() def unregisterProducer(self): # If we received a non-streaming producer, we need to stop the # streaming wrapper: if isinstance(self._producer._producer, _PullToPush): self._producer._producer.stopStreaming() self._producer = None self._producerPaused = False self.transport.unregisterProducer() if self.disconnecting and not self._writeBlockedOnRead: self._shutdownTLS() @implementer(IOpenSSLClientConnectionCreator, IOpenSSLServerConnectionCreator) class _ContextFactoryToConnectionFactory(object): """ Adapter wrapping "something" (ideally something like a L{twisted.internet.ssl.ContextFactory}; implementations of this interface don't actually typically subclass though, so "something" is more likely just something with a C{getContext} method) into an L{IOpenSSLClientConnectionCreator} or L{IOpenSSLServerConnectionCreator}. See U{https://twistedmatrix.com/trac/ticket/7215} for work that should make this unnecessary. """ def __init__(self, oldStyleContextFactory): """ Construct a L{_ContextFactoryToConnectionFactory} with an old-style context factory. Immediately call C{getContext} on C{oldStyleContextFactory} in order to force advance parameter checking, since old-style context factories don't actually check that their arguments to L{OpenSSL} are correct. @param oldStyleContextFactory: A factory that can produce contexts. @type oldStyleContextFactory: L{twisted.internet.ssl.ContextFactory} or something like it. """ oldStyleContextFactory.getContext() self._oldStyleContextFactory = oldStyleContextFactory def _connectionForTLS(self, protocol): """ Create an L{OpenSSL.SSL.Connection} object. @param protocol: The protocol initiating a TLS connection. @type protocol: L{TLSMemoryBIOProtocol} @return: a connection @rtype: L{OpenSSL.SSL.Connection} """ context = self._oldStyleContextFactory.getContext() return Connection(context, None) def serverConnectionForTLS(self, protocol): """ Construct an OpenSSL server connection from the wrapped old-style context factory. @note: Since old-style context factories don't distinguish between clients and servers, this is exactly the same as L{_ContextFactoryToConnectionFactory.clientConnectionForTLS}. @param protocol: The protocol initiating a TLS connection. @type protocol: L{TLSMemoryBIOProtocol} @return: a connection @rtype: L{OpenSSL.SSL.Connection} """ return self._connectionForTLS(protocol) def clientConnectionForTLS(self, protocol): """ Construct an OpenSSL server connection from the wrapped old-style context factory. @note: Since old-style context factories don't distinguish between clients and servers, this is exactly the same as L{_ContextFactoryToConnectionFactory.serverConnectionForTLS}. @param protocol: The protocol initiating a TLS connection. @type protocol: L{TLSMemoryBIOProtocol} @return: a connection @rtype: L{OpenSSL.SSL.Connection} """ return self._connectionForTLS(protocol) class TLSMemoryBIOFactory(WrappingFactory): """ L{TLSMemoryBIOFactory} adds TLS to connections. @ivar _creatorInterface: the interface which L{_connectionCreator} is expected to implement. @type _creatorInterface: L{zope.interface.Interface} @ivar _connectionCreator: a callable which creates an OpenSSL Connection object. @type _connectionCreator: 1-argument callable taking L{TLSMemoryBIOProtocol} and returning L{OpenSSL.SSL.Connection}. """ protocol = TLSMemoryBIOProtocol noisy = False # disable unnecessary logging. def __init__(self, contextFactory, isClient, wrappedFactory): """ Create a L{TLSMemoryBIOFactory}. @param contextFactory: Configuration parameters used to create an OpenSSL connection. In order of preference, what you should pass here should be: 1. L{twisted.internet.ssl.CertificateOptions} (if you're writing a server) or the result of L{twisted.internet.ssl.optionsForClientTLS} (if you're writing a client). If you want security you should really use one of these. 2. If you really want to implement something yourself, supply a provider of L{IOpenSSLClientConnectionCreator} or L{IOpenSSLServerConnectionCreator}. 3. If you really have to, supply a L{twisted.internet.ssl.ContextFactory}. This will likely be deprecated at some point so please upgrade to the new interfaces. @type contextFactory: L{IOpenSSLClientConnectionCreator} or L{IOpenSSLServerConnectionCreator}, or, for compatibility with older code, L{twisted.internet.ssl.ContextFactory}. See U{https://twistedmatrix.com/trac/ticket/7215} for information on the upcoming deprecation of passing a L{twisted.internet.ssl.ContextFactory} here. @param isClient: Is this a factory for TLS client connections; in other words, those that will send a C{ClientHello} greeting? L{True} if so, L{False} otherwise. This flag determines what interface is expected of C{contextFactory}. If L{True}, C{contextFactory} should provide L{IOpenSSLClientConnectionCreator}; otherwise it should provide L{IOpenSSLServerConnectionCreator}. @type isClient: L{bool} @param wrappedFactory: A factory which will create the application-level protocol. @type wrappedFactory: L{twisted.internet.interfaces.IProtocolFactory} """ WrappingFactory.__init__(self, wrappedFactory) if isClient: creatorInterface = IOpenSSLClientConnectionCreator else: creatorInterface = IOpenSSLServerConnectionCreator self._creatorInterface = creatorInterface if not creatorInterface.providedBy(contextFactory): contextFactory = _ContextFactoryToConnectionFactory(contextFactory) self._connectionCreator = contextFactory def logPrefix(self): """ Annotate the wrapped factory's log prefix with some text indicating TLS is in use. @rtype: C{str} """ if ILoggingContext.providedBy(self.wrappedFactory): logPrefix = self.wrappedFactory.logPrefix() else: logPrefix = self.wrappedFactory.__class__.__name__ return "%s (TLS)" % (logPrefix,) def _createConnection(self, tlsProtocol): """ Create an OpenSSL connection and set it up good. @param tlsProtocol: The protocol which is establishing the connection. @type tlsProtocol: L{TLSMemoryBIOProtocol} @return: an OpenSSL connection object for C{tlsProtocol} to use @rtype: L{OpenSSL.SSL.Connection} """ connectionCreator = self._connectionCreator if self._creatorInterface is IOpenSSLClientConnectionCreator: connection = connectionCreator.clientConnectionForTLS(tlsProtocol) connection.set_connect_state() else: connection = connectionCreator.serverConnectionForTLS(tlsProtocol) connection.set_accept_state() return connection