""" MAIN CLASS FOR TLS LITE (START HERE!). """ from __future__ import generators import socket from utils.compat import formatExceptionTrace from TLSRecordLayer import TLSRecordLayer from Session import Session from constants import * from utils.cryptomath import getRandomBytes from errors import * from messages import * from mathtls import * from HandshakeSettings import HandshakeSettings class TLSConnection(TLSRecordLayer): """ This class wraps a socket and provides TLS handshaking and data transfer. To use this class, create a new instance, passing a connected socket into the constructor. Then call some handshake function. If the handshake completes without raising an exception, then a TLS connection has been negotiated. You can transfer data over this connection as if it were a socket. This class provides both synchronous and asynchronous versions of its key functions. The synchronous versions should be used when writing single-or multi-threaded code using blocking sockets. The asynchronous versions should be used when performing asynchronous, event-based I/O with non-blocking sockets. Asynchronous I/O is a complicated subject; typically, you should not use the asynchronous functions directly, but should use some framework like asyncore or Twisted which TLS Lite integrates with (see L{tlslite.integration.TLSAsyncDispatcherMixIn.TLSAsyncDispatcherMixIn} or L{tlslite.integration.TLSTwistedProtocolWrapper.TLSTwistedProtocolWrapper}). """ def __init__(self, sock): """Create a new TLSConnection instance. @param sock: The socket data will be transmitted on. The socket should already be connected. It may be in blocking or non-blocking mode. @type sock: L{socket.socket} """ TLSRecordLayer.__init__(self, sock) def handshakeClientSRP(self, username, password, session=None, settings=None, checker=None, async=False): """Perform an SRP handshake in the role of client. This function performs a TLS/SRP handshake. SRP mutually authenticates both parties to each other using only a username and password. This function may also perform a combined SRP and server-certificate handshake, if the server chooses to authenticate itself with a certificate chain in addition to doing SRP. TLS/SRP is non-standard. Most TLS implementations don't support it. See U{http://www.ietf.org/html.charters/tls-charter.html} or U{http://trevp.net/tlssrp/} for the latest information on TLS/SRP. Like any handshake function, this can be called on a closed TLS connection, or on a TLS connection that is already open. If called on an open connection it performs a re-handshake. If the function completes without raising an exception, the TLS connection will be open and available for data transfer. If an exception is raised, the connection will have been automatically closed (if it was ever open). @type username: str @param username: The SRP username. @type password: str @param password: The SRP password. @type session: L{tlslite.Session.Session} @param session: A TLS session to attempt to resume. This session must be an SRP session performed with the same username and password as were passed in. If the resumption does not succeed, a full SRP handshake will be performed. @type settings: L{tlslite.HandshakeSettings.HandshakeSettings} @param settings: Various settings which can be used to control the ciphersuites, certificate types, and SSL/TLS versions offered by the client. @type checker: L{tlslite.Checker.Checker} @param checker: A Checker instance. This instance will be invoked to examine the other party's authentication credentials, if the handshake completes succesfully. @type async: bool @param async: If False, this function will block until the handshake is completed. If True, this function will return a generator. Successive invocations of the generator will return 0 if it is waiting to read from the socket, 1 if it is waiting to write to the socket, or will raise StopIteration if the handshake operation is completed. @rtype: None or an iterable @return: If 'async' is True, a generator object will be returned. @raise socket.error: If a socket error occurs. @raise tlslite.errors.TLSAbruptCloseError: If the socket is closed without a preceding alert. @raise tlslite.errors.TLSAlert: If a TLS alert is signalled. @raise tlslite.errors.TLSAuthenticationError: If the checker doesn't like the other party's authentication credentials. """ handshaker = self._handshakeClientAsync(srpParams=(username, password), session=session, settings=settings, checker=checker) if async: return handshaker for result in handshaker: pass def handshakeClientCert(self, certChain=None, privateKey=None, session=None, settings=None, checker=None, async=False): """Perform a certificate-based handshake in the role of client. This function performs an SSL or TLS handshake. The server will authenticate itself using an X.509 or cryptoID certificate chain. If the handshake succeeds, the server's certificate chain will be stored in the session's serverCertChain attribute. Unless a checker object is passed in, this function does no validation or checking of the server's certificate chain. If the server requests client authentication, the client will send the passed-in certificate chain, and use the passed-in private key to authenticate itself. If no certificate chain and private key were passed in, the client will attempt to proceed without client authentication. The server may or may not allow this. Like any handshake function, this can be called on a closed TLS connection, or on a TLS connection that is already open. If called on an open connection it performs a re-handshake. If the function completes without raising an exception, the TLS connection will be open and available for data transfer. If an exception is raised, the connection will have been automatically closed (if it was ever open). @type certChain: L{tlslite.X509CertChain.X509CertChain} or L{cryptoIDlib.CertChain.CertChain} @param certChain: The certificate chain to be used if the server requests client authentication. @type privateKey: L{tlslite.utils.RSAKey.RSAKey} @param privateKey: The private key to be used if the server requests client authentication. @type session: L{tlslite.Session.Session} @param session: A TLS session to attempt to resume. If the resumption does not succeed, a full handshake will be performed. @type settings: L{tlslite.HandshakeSettings.HandshakeSettings} @param settings: Various settings which can be used to control the ciphersuites, certificate types, and SSL/TLS versions offered by the client. @type checker: L{tlslite.Checker.Checker} @param checker: A Checker instance. This instance will be invoked to examine the other party's authentication credentials, if the handshake completes succesfully. @type async: bool @param async: If False, this function will block until the handshake is completed. If True, this function will return a generator. Successive invocations of the generator will return 0 if it is waiting to read from the socket, 1 if it is waiting to write to the socket, or will raise StopIteration if the handshake operation is completed. @rtype: None or an iterable @return: If 'async' is True, a generator object will be returned. @raise socket.error: If a socket error occurs. @raise tlslite.errors.TLSAbruptCloseError: If the socket is closed without a preceding alert. @raise tlslite.errors.TLSAlert: If a TLS alert is signalled. @raise tlslite.errors.TLSAuthenticationError: If the checker doesn't like the other party's authentication credentials. """ handshaker = self._handshakeClientAsync(certParams=(certChain, privateKey), session=session, settings=settings, checker=checker) if async: return handshaker for result in handshaker: pass def handshakeClientUnknown(self, srpCallback=None, certCallback=None, session=None, settings=None, checker=None, async=False): """Perform a to-be-determined type of handshake in the role of client. This function performs an SSL or TLS handshake. If the server requests client certificate authentication, the certCallback will be invoked and should return a (certChain, privateKey) pair. If the callback returns None, the library will attempt to proceed without client authentication. The server may or may not allow this. If the server requests SRP authentication, the srpCallback will be invoked and should return a (username, password) pair. If the callback returns None, the local implementation will signal a user_canceled error alert. After the handshake completes, the client can inspect the connection's session attribute to determine what type of authentication was performed. Like any handshake function, this can be called on a closed TLS connection, or on a TLS connection that is already open. If called on an open connection it performs a re-handshake. If the function completes without raising an exception, the TLS connection will be open and available for data transfer. If an exception is raised, the connection will have been automatically closed (if it was ever open). @type srpCallback: callable @param srpCallback: The callback to be used if the server requests SRP authentication. If None, the client will not offer support for SRP ciphersuites. @type certCallback: callable @param certCallback: The callback to be used if the server requests client certificate authentication. @type session: L{tlslite.Session.Session} @param session: A TLS session to attempt to resume. If the resumption does not succeed, a full handshake will be performed. @type settings: L{tlslite.HandshakeSettings.HandshakeSettings} @param settings: Various settings which can be used to control the ciphersuites, certificate types, and SSL/TLS versions offered by the client. @type checker: L{tlslite.Checker.Checker} @param checker: A Checker instance. This instance will be invoked to examine the other party's authentication credentials, if the handshake completes succesfully. @type async: bool @param async: If False, this function will block until the handshake is completed. If True, this function will return a generator. Successive invocations of the generator will return 0 if it is waiting to read from the socket, 1 if it is waiting to write to the socket, or will raise StopIteration if the handshake operation is completed. @rtype: None or an iterable @return: If 'async' is True, a generator object will be returned. @raise socket.error: If a socket error occurs. @raise tlslite.errors.TLSAbruptCloseError: If the socket is closed without a preceding alert. @raise tlslite.errors.TLSAlert: If a TLS alert is signalled. @raise tlslite.errors.TLSAuthenticationError: If the checker doesn't like the other party's authentication credentials. """ handshaker = self._handshakeClientAsync(unknownParams=(srpCallback, certCallback), session=session, settings=settings, checker=checker) if async: return handshaker for result in handshaker: pass def handshakeClientSharedKey(self, username, sharedKey, settings=None, checker=None, async=False): """Perform a shared-key handshake in the role of client. This function performs a shared-key handshake. Using shared symmetric keys of high entropy (128 bits or greater) mutually authenticates both parties to each other. TLS with shared-keys is non-standard. Most TLS implementations don't support it. See U{http://www.ietf.org/html.charters/tls-charter.html} for the latest information on TLS with shared-keys. If the shared-keys Internet-Draft changes or is superceded, TLS Lite will track those changes, so the shared-key support in later versions of TLS Lite may become incompatible with this version. Like any handshake function, this can be called on a closed TLS connection, or on a TLS connection that is already open. If called on an open connection it performs a re-handshake. If the function completes without raising an exception, the TLS connection will be open and available for data transfer. If an exception is raised, the connection will have been automatically closed (if it was ever open). @type username: str @param username: The shared-key username. @type sharedKey: str @param sharedKey: The shared key. @type settings: L{tlslite.HandshakeSettings.HandshakeSettings} @param settings: Various settings which can be used to control the ciphersuites, certificate types, and SSL/TLS versions offered by the client. @type checker: L{tlslite.Checker.Checker} @param checker: A Checker instance. This instance will be invoked to examine the other party's authentication credentials, if the handshake completes succesfully. @type async: bool @param async: If False, this function will block until the handshake is completed. If True, this function will return a generator. Successive invocations of the generator will return 0 if it is waiting to read from the socket, 1 if it is waiting to write to the socket, or will raise StopIteration if the handshake operation is completed. @rtype: None or an iterable @return: If 'async' is True, a generator object will be returned. @raise socket.error: If a socket error occurs. @raise tlslite.errors.TLSAbruptCloseError: If the socket is closed without a preceding alert. @raise tlslite.errors.TLSAlert: If a TLS alert is signalled. @raise tlslite.errors.TLSAuthenticationError: If the checker doesn't like the other party's authentication credentials. """ handshaker = self._handshakeClientAsync(sharedKeyParams=(username, sharedKey), settings=settings, checker=checker) if async: return handshaker for result in handshaker: pass def _handshakeClientAsync(self, srpParams=(), certParams=(), unknownParams=(), sharedKeyParams=(), session=None, settings=None, checker=None, recursive=False): handshaker = self._handshakeClientAsyncHelper(srpParams=srpParams, certParams=certParams, unknownParams=unknownParams, sharedKeyParams=sharedKeyParams, session=session, settings=settings, recursive=recursive) for result in self._handshakeWrapperAsync(handshaker, checker): yield result def _handshakeClientAsyncHelper(self, srpParams, certParams, unknownParams, sharedKeyParams, session, settings, recursive): if not recursive: self._handshakeStart(client=True) #Unpack parameters srpUsername = None # srpParams password = None # srpParams clientCertChain = None # certParams privateKey = None # certParams srpCallback = None # unknownParams certCallback = None # unknownParams #session # sharedKeyParams (or session) #settings # settings if srpParams: srpUsername, password = srpParams elif certParams: clientCertChain, privateKey = certParams elif unknownParams: srpCallback, certCallback = unknownParams elif sharedKeyParams: session = Session()._createSharedKey(*sharedKeyParams) if not settings: settings = HandshakeSettings() settings = settings._filter() #Validate parameters if srpUsername and not password: raise ValueError("Caller passed a username but no password") if password and not srpUsername: raise ValueError("Caller passed a password but no username") if clientCertChain and not privateKey: raise ValueError("Caller passed a certChain but no privateKey") if privateKey and not clientCertChain: raise ValueError("Caller passed a privateKey but no certChain") if clientCertChain: foundType = False try: import cryptoIDlib.CertChain if isinstance(clientCertChain, cryptoIDlib.CertChain.CertChain): if "cryptoID" not in settings.certificateTypes: raise ValueError("Client certificate doesn't "\ "match Handshake Settings") settings.certificateTypes = ["cryptoID"] foundType = True except ImportError: pass if not foundType and isinstance(clientCertChain, X509CertChain): if "x509" not in settings.certificateTypes: raise ValueError("Client certificate doesn't match "\ "Handshake Settings") settings.certificateTypes = ["x509"] foundType = True if not foundType: raise ValueError("Unrecognized certificate type") if session: if not session.valid(): session = None #ignore non-resumable sessions... elif session.resumable and \ (session.srpUsername != srpUsername): raise ValueError("Session username doesn't match") #Add Faults to parameters if srpUsername and self.fault == Fault.badUsername: srpUsername += "GARBAGE" if password and self.fault == Fault.badPassword: password += "GARBAGE" if sharedKeyParams: identifier = sharedKeyParams[0] sharedKey = sharedKeyParams[1] if self.fault == Fault.badIdentifier: identifier += "GARBAGE" session = Session()._createSharedKey(identifier, sharedKey) elif self.fault == Fault.badSharedKey: sharedKey += "GARBAGE" session = Session()._createSharedKey(identifier, sharedKey) #Initialize locals serverCertChain = None cipherSuite = 0 certificateType = CertificateType.x509 premasterSecret = None #Get client nonce clientRandom = getRandomBytes(32) #Initialize acceptable ciphersuites cipherSuites = [] if srpParams: cipherSuites += CipherSuite.getSrpRsaSuites(settings.cipherNames) cipherSuites += CipherSuite.getSrpSuites(settings.cipherNames) elif certParams: cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames) elif unknownParams: if srpCallback: cipherSuites += \ CipherSuite.getSrpRsaSuites(settings.cipherNames) cipherSuites += \ CipherSuite.getSrpSuites(settings.cipherNames) cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames) elif sharedKeyParams: cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames) else: cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames) #Initialize acceptable certificate types certificateTypes = settings._getCertificateTypes() #Tentatively set the version to the client's minimum version. #We'll use this for the ClientHello, and if an error occurs #parsing the Server Hello, we'll use this version for the response self.version = settings.maxVersion #Either send ClientHello (with a resumable session)... if session: #If it's a resumable (i.e. not a shared-key session), then its #ciphersuite must be one of the acceptable ciphersuites if (not sharedKeyParams) and \ session.cipherSuite not in cipherSuites: raise ValueError("Session's cipher suite not consistent "\ "with parameters") else: clientHello = ClientHello() clientHello.create(settings.maxVersion, clientRandom, session.sessionID, cipherSuites, certificateTypes, session.srpUsername) #Or send ClientHello (without) else: clientHello = ClientHello() clientHello.create(settings.maxVersion, clientRandom, createByteArraySequence([]), cipherSuites, certificateTypes, srpUsername) for result in self._sendMsg(clientHello): yield result #Get ServerHello (or missing_srp_username) for result in self._getMsg((ContentType.handshake, ContentType.alert), HandshakeType.server_hello): if result in (0,1): yield result else: break msg = result if isinstance(msg, ServerHello): serverHello = msg elif isinstance(msg, Alert): alert = msg #If it's not a missing_srp_username, re-raise if alert.description != AlertDescription.missing_srp_username: self._shutdown(False) raise TLSRemoteAlert(alert) #If we're not in SRP callback mode, we won't have offered SRP #without a username, so we shouldn't get this alert if not srpCallback: for result in self._sendError(\ AlertDescription.unexpected_message): yield result srpParams = srpCallback() #If the callback returns None, cancel the handshake if srpParams == None: for result in self._sendError(AlertDescription.user_canceled): yield result #Recursively perform handshake for result in self._handshakeClientAsyncHelper(srpParams, None, None, None, None, settings, True): yield result return #Get the server version. Do this before anything else, so any #error alerts will use the server's version self.version = serverHello.server_version #Future responses from server must use this version self._versionCheck = True #Check ServerHello if serverHello.server_version < settings.minVersion: for result in self._sendError(\ AlertDescription.protocol_version, "Too old version: %s" % str(serverHello.server_version)): yield result if serverHello.server_version > settings.maxVersion: for result in self._sendError(\ AlertDescription.protocol_version, "Too new version: %s" % str(serverHello.server_version)): yield result if serverHello.cipher_suite not in cipherSuites: for result in self._sendError(\ AlertDescription.illegal_parameter, "Server responded with incorrect ciphersuite"): yield result if serverHello.certificate_type not in certificateTypes: for result in self._sendError(\ AlertDescription.illegal_parameter, "Server responded with incorrect certificate type"): yield result if serverHello.compression_method != 0: for result in self._sendError(\ AlertDescription.illegal_parameter, "Server responded with incorrect compression method"): yield result #Get the server nonce serverRandom = serverHello.random #If the server agrees to resume if session and session.sessionID and \ serverHello.session_id == session.sessionID: #If a shared-key, we're flexible about suites; otherwise the #server-chosen suite has to match the session's suite if sharedKeyParams: session.cipherSuite = serverHello.cipher_suite elif serverHello.cipher_suite != session.cipherSuite: for result in self._sendError(\ AlertDescription.illegal_parameter,\ "Server's ciphersuite doesn't match session"): yield result #Set the session for this connection self.session = session #Calculate pending connection states self._calcPendingStates(clientRandom, serverRandom, settings.cipherImplementations) #Exchange ChangeCipherSpec and Finished messages for result in self._getFinished(): yield result for result in self._sendFinished(): yield result #Mark the connection as open self._handshakeDone(resumed=True) #If server DOES NOT agree to resume else: if sharedKeyParams: for result in self._sendError(\ AlertDescription.user_canceled, "Was expecting a shared-key resumption"): yield result #We've already validated these cipherSuite = serverHello.cipher_suite certificateType = serverHello.certificate_type #If the server chose an SRP suite... if cipherSuite in CipherSuite.srpSuites: #Get ServerKeyExchange, ServerHelloDone for result in self._getMsg(ContentType.handshake, HandshakeType.server_key_exchange, cipherSuite): if result in (0,1): yield result else: break serverKeyExchange = result for result in self._getMsg(ContentType.handshake, HandshakeType.server_hello_done): if result in (0,1): yield result else: break serverHelloDone = result #If the server chose an SRP+RSA suite... elif cipherSuite in CipherSuite.srpRsaSuites: #Get Certificate, ServerKeyExchange, ServerHelloDone for result in self._getMsg(ContentType.handshake, HandshakeType.certificate, certificateType): if result in (0,1): yield result else: break serverCertificate = result for result in self._getMsg(ContentType.handshake, HandshakeType.server_key_exchange, cipherSuite): if result in (0,1): yield result else: break serverKeyExchange = result for result in self._getMsg(ContentType.handshake, HandshakeType.server_hello_done): if result in (0,1): yield result else: break serverHelloDone = result #If the server chose an RSA suite... elif cipherSuite in CipherSuite.rsaSuites: #Get Certificate[, CertificateRequest], ServerHelloDone for result in self._getMsg(ContentType.handshake, HandshakeType.certificate, certificateType): if result in (0,1): yield result else: break serverCertificate = result for result in self._getMsg(ContentType.handshake, (HandshakeType.server_hello_done, HandshakeType.certificate_request)): if result in (0,1): yield result else: break msg = result certificateRequest = None if isinstance(msg, CertificateRequest): certificateRequest = msg for result in self._getMsg(ContentType.handshake, HandshakeType.server_hello_done): if result in (0,1): yield result else: break serverHelloDone = result elif isinstance(msg, ServerHelloDone): serverHelloDone = msg else: raise AssertionError() #Calculate SRP premaster secret, if server chose an SRP or #SRP+RSA suite if cipherSuite in CipherSuite.srpSuites + \ CipherSuite.srpRsaSuites: #Get and check the server's group parameters and B value N = serverKeyExchange.srp_N g = serverKeyExchange.srp_g s = serverKeyExchange.srp_s B = serverKeyExchange.srp_B if (g,N) not in goodGroupParameters: for result in self._sendError(\ AlertDescription.untrusted_srp_parameters, "Unknown group parameters"): yield result if numBits(N) < settings.minKeySize: for result in self._sendError(\ AlertDescription.untrusted_srp_parameters, "N value is too small: %d" % numBits(N)): yield result if numBits(N) > settings.maxKeySize: for result in self._sendError(\ AlertDescription.untrusted_srp_parameters, "N value is too large: %d" % numBits(N)): yield result if B % N == 0: for result in self._sendError(\ AlertDescription.illegal_parameter, "Suspicious B value"): yield result #Check the server's signature, if server chose an #SRP+RSA suite if cipherSuite in CipherSuite.srpRsaSuites: #Hash ServerKeyExchange/ServerSRPParams hashBytes = serverKeyExchange.hash(clientRandom, serverRandom) #Extract signature bytes from ServerKeyExchange sigBytes = serverKeyExchange.signature if len(sigBytes) == 0: for result in self._sendError(\ AlertDescription.illegal_parameter, "Server sent an SRP ServerKeyExchange "\ "message without a signature"): yield result #Get server's public key from the Certificate message for result in self._getKeyFromChain(serverCertificate, settings): if result in (0,1): yield result else: break publicKey, serverCertChain = result #Verify signature if not publicKey.verify(sigBytes, hashBytes): for result in self._sendError(\ AlertDescription.decrypt_error, "Signature failed to verify"): yield result #Calculate client's ephemeral DH values (a, A) a = bytesToNumber(getRandomBytes(32)) A = powMod(g, a, N) #Calculate client's static DH values (x, v) x = makeX(bytesToString(s), srpUsername, password) v = powMod(g, x, N) #Calculate u u = makeU(N, A, B) #Calculate premaster secret k = makeK(N, g) S = powMod((B - (k*v)) % N, a+(u*x), N) if self.fault == Fault.badA: A = N S = 0 premasterSecret = numberToBytes(S) #Send ClientKeyExchange for result in self._sendMsg(\ ClientKeyExchange(cipherSuite).createSRP(A)): yield result #Calculate RSA premaster secret, if server chose an RSA suite elif cipherSuite in CipherSuite.rsaSuites: #Handle the presence of a CertificateRequest if certificateRequest: if unknownParams and certCallback: certParamsNew = certCallback() if certParamsNew: clientCertChain, privateKey = certParamsNew #Get server's public key from the Certificate message for result in self._getKeyFromChain(serverCertificate, settings): if result in (0,1): yield result else: break publicKey, serverCertChain = result #Calculate premaster secret premasterSecret = getRandomBytes(48) premasterSecret[0] = settings.maxVersion[0] premasterSecret[1] = settings.maxVersion[1] if self.fault == Fault.badPremasterPadding: premasterSecret[0] = 5 if self.fault == Fault.shortPremasterSecret: premasterSecret = premasterSecret[:-1] #Encrypt premaster secret to server's public key encryptedPreMasterSecret = publicKey.encrypt(premasterSecret) #If client authentication was requested, send Certificate #message, either with certificates or empty if certificateRequest: clientCertificate = Certificate(certificateType) if clientCertChain: #Check to make sure we have the same type of #certificates the server requested wrongType = False if certificateType == CertificateType.x509: if not isinstance(clientCertChain, X509CertChain): wrongType = True elif certificateType == CertificateType.cryptoID: if not isinstance(clientCertChain, cryptoIDlib.CertChain.CertChain): wrongType = True if wrongType: for result in self._sendError(\ AlertDescription.handshake_failure, "Client certificate is of wrong type"): yield result clientCertificate.create(clientCertChain) for result in self._sendMsg(clientCertificate): yield result else: #The server didn't request client auth, so we #zeroize these so the clientCertChain won't be #stored in the session. privateKey = None clientCertChain = None #Send ClientKeyExchange clientKeyExchange = ClientKeyExchange(cipherSuite, self.version) clientKeyExchange.createRSA(encryptedPreMasterSecret) for result in self._sendMsg(clientKeyExchange): yield result #If client authentication was requested and we have a #private key, send CertificateVerify if certificateRequest and privateKey: if self.version == (3,0): #Create a temporary session object, just for the #purpose of creating the CertificateVerify session = Session() session._calcMasterSecret(self.version, premasterSecret, clientRandom, serverRandom) verifyBytes = self._calcSSLHandshakeHash(\ session.masterSecret, "") elif self.version in ((3,1), (3,2)): verifyBytes = stringToBytes(\ self._handshake_md5.digest() + \ self._handshake_sha.digest()) if self.fault == Fault.badVerifyMessage: verifyBytes[0] = ((verifyBytes[0]+1) % 256) signedBytes = privateKey.sign(verifyBytes) certificateVerify = CertificateVerify() certificateVerify.create(signedBytes) for result in self._sendMsg(certificateVerify): yield result #Create the session object self.session = Session() self.session._calcMasterSecret(self.version, premasterSecret, clientRandom, serverRandom) self.session.sessionID = serverHello.session_id self.session.cipherSuite = cipherSuite self.session.srpUsername = srpUsername self.session.clientCertChain = clientCertChain self.session.serverCertChain = serverCertChain #Calculate pending connection states self._calcPendingStates(clientRandom, serverRandom, settings.cipherImplementations) #Exchange ChangeCipherSpec and Finished messages for result in self._sendFinished(): yield result for result in self._getFinished(): yield result #Mark the connection as open self.session._setResumable(True) self._handshakeDone(resumed=False) def handshakeServer(self, sharedKeyDB=None, verifierDB=None, certChain=None, privateKey=None, reqCert=False, sessionCache=None, settings=None, checker=None): """Perform a handshake in the role of server. This function performs an SSL or TLS handshake. Depending on the arguments and the behavior of the client, this function can perform a shared-key, SRP, or certificate-based handshake. It can also perform a combined SRP and server-certificate handshake. Like any handshake function, this can be called on a closed TLS connection, or on a TLS connection that is already open. If called on an open connection it performs a re-handshake. This function does not send a Hello Request message before performing the handshake, so if re-handshaking is required, the server must signal the client to begin the re-handshake through some other means. If the function completes without raising an exception, the TLS connection will be open and available for data transfer. If an exception is raised, the connection will have been automatically closed (if it was ever open). @type sharedKeyDB: L{tlslite.SharedKeyDB.SharedKeyDB} @param sharedKeyDB: A database of shared symmetric keys associated with usernames. If the client performs a shared-key handshake, the session's sharedKeyUsername attribute will be set. @type verifierDB: L{tlslite.VerifierDB.VerifierDB} @param verifierDB: A database of SRP password verifiers associated with usernames. If the client performs an SRP handshake, the session's srpUsername attribute will be set. @type certChain: L{tlslite.X509CertChain.X509CertChain} or L{cryptoIDlib.CertChain.CertChain} @param certChain: The certificate chain to be used if the client requests server certificate authentication. @type privateKey: L{tlslite.utils.RSAKey.RSAKey} @param privateKey: The private key to be used if the client requests server certificate authentication. @type reqCert: bool @param reqCert: Whether to request client certificate authentication. This only applies if the client chooses server certificate authentication; if the client chooses SRP or shared-key authentication, this will be ignored. If the client performs a client certificate authentication, the sessions's clientCertChain attribute will be set. @type sessionCache: L{tlslite.SessionCache.SessionCache} @param sessionCache: An in-memory cache of resumable sessions. The client can resume sessions from this cache. Alternatively, if the client performs a full handshake, a new session will be added to the cache. @type settings: L{tlslite.HandshakeSettings.HandshakeSettings} @param settings: Various settings which can be used to control the ciphersuites and SSL/TLS version chosen by the server. @type checker: L{tlslite.Checker.Checker} @param checker: A Checker instance. This instance will be invoked to examine the other party's authentication credentials, if the handshake completes succesfully. @raise socket.error: If a socket error occurs. @raise tlslite.errors.TLSAbruptCloseError: If the socket is closed without a preceding alert. @raise tlslite.errors.TLSAlert: If a TLS alert is signalled. @raise tlslite.errors.TLSAuthenticationError: If the checker doesn't like the other party's authentication credentials. """ for result in self.handshakeServerAsync(sharedKeyDB, verifierDB, certChain, privateKey, reqCert, sessionCache, settings, checker): pass def handshakeServerAsync(self, sharedKeyDB=None, verifierDB=None, certChain=None, privateKey=None, reqCert=False, sessionCache=None, settings=None, checker=None): """Start a server handshake operation on the TLS connection. This function returns a generator which behaves similarly to handshakeServer(). Successive invocations of the generator will return 0 if it is waiting to read from the socket, 1 if it is waiting to write to the socket, or it will raise StopIteration if the handshake operation is complete. @rtype: iterable @return: A generator; see above for details. """ handshaker = self._handshakeServerAsyncHelper(\ sharedKeyDB=sharedKeyDB, verifierDB=verifierDB, certChain=certChain, privateKey=privateKey, reqCert=reqCert, sessionCache=sessionCache, settings=settings) for result in self._handshakeWrapperAsync(handshaker, checker): yield result def _handshakeServerAsyncHelper(self, sharedKeyDB, verifierDB, certChain, privateKey, reqCert, sessionCache, settings): self._handshakeStart(client=False) if (not sharedKeyDB) and (not verifierDB) and (not certChain): raise ValueError("Caller passed no authentication credentials") if certChain and not privateKey: raise ValueError("Caller passed a certChain but no privateKey") if privateKey and not certChain: raise ValueError("Caller passed a privateKey but no certChain") if not settings: settings = HandshakeSettings() settings = settings._filter() #Initialize acceptable cipher suites cipherSuites = [] if verifierDB: if certChain: cipherSuites += \ CipherSuite.getSrpRsaSuites(settings.cipherNames) cipherSuites += CipherSuite.getSrpSuites(settings.cipherNames) if sharedKeyDB or certChain: cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames) #Initialize acceptable certificate type certificateType = None if certChain: try: import cryptoIDlib.CertChain if isinstance(certChain, cryptoIDlib.CertChain.CertChain): certificateType = CertificateType.cryptoID except ImportError: pass if isinstance(certChain, X509CertChain): certificateType = CertificateType.x509 if certificateType == None: raise ValueError("Unrecognized certificate type") #Initialize locals clientCertChain = None serverCertChain = None #We may set certChain to this later postFinishedError = None #Tentatively set version to most-desirable version, so if an error #occurs parsing the ClientHello, this is what we'll use for the #error alert self.version = settings.maxVersion #Get ClientHello for result in self._getMsg(ContentType.handshake, HandshakeType.client_hello): if result in (0,1): yield result else: break clientHello = result #If client's version is too low, reject it if clientHello.client_version < settings.minVersion: self.version = settings.minVersion for result in self._sendError(\ AlertDescription.protocol_version, "Too old version: %s" % str(clientHello.client_version)): yield result #If client's version is too high, propose my highest version elif clientHello.client_version > settings.maxVersion: self.version = settings.maxVersion else: #Set the version to the client's version self.version = clientHello.client_version #Get the client nonce; create server nonce clientRandom = clientHello.random serverRandom = getRandomBytes(32) #Calculate the first cipher suite intersection. #This is the 'privileged' ciphersuite. We'll use it if we're #doing a shared-key resumption or a new negotiation. In fact, #the only time we won't use it is if we're resuming a non-sharedkey #session, in which case we use the ciphersuite from the session. # #Given the current ciphersuite ordering, this means we prefer SRP #over non-SRP. for cipherSuite in cipherSuites: if cipherSuite in clientHello.cipher_suites: break else: for result in self._sendError(\ AlertDescription.handshake_failure): yield result #If resumption was requested... if clientHello.session_id and (sharedKeyDB or sessionCache): session = None #Check in the sharedKeys container if sharedKeyDB and len(clientHello.session_id)==16: try: #Trim off zero padding, if any for x in range(16): if clientHello.session_id[x]==0: break self.allegedSharedKeyUsername = bytesToString(\ clientHello.session_id[:x]) session = sharedKeyDB[self.allegedSharedKeyUsername] if not session.sharedKey: raise AssertionError() #use privileged ciphersuite session.cipherSuite = cipherSuite except KeyError: pass #Then check in the session cache if sessionCache and not session: try: session = sessionCache[bytesToString(\ clientHello.session_id)] if session.sharedKey: raise AssertionError() if not session.resumable: raise AssertionError() #Check for consistency with ClientHello if session.cipherSuite not in cipherSuites: for result in self._sendError(\ AlertDescription.handshake_failure): yield result if session.cipherSuite not in clientHello.cipher_suites: for result in self._sendError(\ AlertDescription.handshake_failure): yield result if clientHello.srp_username: if clientHello.srp_username != session.srpUsername: for result in self._sendError(\ AlertDescription.handshake_failure): yield result except KeyError: pass #If a session is found.. if session: #Set the session self.session = session #Send ServerHello serverHello = ServerHello() serverHello.create(self.version, serverRandom, session.sessionID, session.cipherSuite, certificateType) for result in self._sendMsg(serverHello): yield result #From here on, the client's messages must have the right version self._versionCheck = True #Calculate pending connection states self._calcPendingStates(clientRandom, serverRandom, settings.cipherImplementations) #Exchange ChangeCipherSpec and Finished messages for result in self._sendFinished(): yield result for result in self._getFinished(): yield result #Mark the connection as open self._handshakeDone(resumed=True) return #If not a resumption... #TRICKY: we might have chosen an RSA suite that was only deemed #acceptable because of the shared-key resumption. If the shared- #key resumption failed, because the identifier wasn't recognized, #we might fall through to here, where we have an RSA suite #chosen, but no certificate. if cipherSuite in CipherSuite.rsaSuites and not certChain: for result in self._sendError(\ AlertDescription.handshake_failure): yield result #If an RSA suite is chosen, check for certificate type intersection #(We do this check down here because if the mismatch occurs but the # client is using a shared-key session, it's okay) if cipherSuite in CipherSuite.rsaSuites + \ CipherSuite.srpRsaSuites: if certificateType not in clientHello.certificate_types: for result in self._sendError(\ AlertDescription.handshake_failure, "the client doesn't support my certificate type"): yield result #Move certChain -> serverCertChain, now that we're using it serverCertChain = certChain #Create sessionID if sessionCache: sessionID = getRandomBytes(32) else: sessionID = createByteArraySequence([]) #If we've selected an SRP suite, exchange keys and calculate #premaster secret: if cipherSuite in CipherSuite.srpSuites + CipherSuite.srpRsaSuites: #If there's no SRP username... if not clientHello.srp_username: #Ask the client to re-send ClientHello with one for result in self._sendMsg(Alert().create(\ AlertDescription.missing_srp_username, AlertLevel.warning)): yield result #Get ClientHello for result in self._getMsg(ContentType.handshake, HandshakeType.client_hello): if result in (0,1): yield result else: break clientHello = result #Check ClientHello #If client's version is too low, reject it (COPIED CODE; BAD!) if clientHello.client_version < settings.minVersion: self.version = settings.minVersion for result in self._sendError(\ AlertDescription.protocol_version, "Too old version: %s" % str(clientHello.client_version)): yield result #If client's version is too high, propose my highest version elif clientHello.client_version > settings.maxVersion: self.version = settings.maxVersion else: #Set the version to the client's version self.version = clientHello.client_version #Recalculate the privileged cipher suite, making sure to #pick an SRP suite cipherSuites = [c for c in cipherSuites if c in \ CipherSuite.srpSuites + \ CipherSuite.srpRsaSuites] for cipherSuite in cipherSuites: if cipherSuite in clientHello.cipher_suites: break else: for result in self._sendError(\ AlertDescription.handshake_failure): yield result #Get the client nonce; create server nonce clientRandom = clientHello.random serverRandom = getRandomBytes(32) #The username better be there, this time if not clientHello.srp_username: for result in self._sendError(\ AlertDescription.illegal_parameter, "Client resent a hello, but without the SRP"\ " username"): yield result #Get username self.allegedSrpUsername = clientHello.srp_username #Get parameters from username try: entry = verifierDB[self.allegedSrpUsername] except KeyError: for result in self._sendError(\ AlertDescription.unknown_srp_username): yield result (N, g, s, v) = entry #Calculate server's ephemeral DH values (b, B) b = bytesToNumber(getRandomBytes(32)) k = makeK(N, g) B = (powMod(g, b, N) + (k*v)) % N #Create ServerKeyExchange, signing it if necessary serverKeyExchange = ServerKeyExchange(cipherSuite) serverKeyExchange.createSRP(N, g, stringToBytes(s), B) if cipherSuite in CipherSuite.srpRsaSuites: hashBytes = serverKeyExchange.hash(clientRandom, serverRandom) serverKeyExchange.signature = privateKey.sign(hashBytes) #Send ServerHello[, Certificate], ServerKeyExchange, #ServerHelloDone msgs = [] serverHello = ServerHello() serverHello.create(self.version, serverRandom, sessionID, cipherSuite, certificateType) msgs.append(serverHello) if cipherSuite in CipherSuite.srpRsaSuites: certificateMsg = Certificate(certificateType) certificateMsg.create(serverCertChain) msgs.append(certificateMsg) msgs.append(serverKeyExchange) msgs.append(ServerHelloDone()) for result in self._sendMsgs(msgs): yield result #From here on, the client's messages must have the right version self._versionCheck = True #Get and check ClientKeyExchange for result in self._getMsg(ContentType.handshake, HandshakeType.client_key_exchange, cipherSuite): if result in (0,1): yield result else: break clientKeyExchange = result A = clientKeyExchange.srp_A if A % N == 0: postFinishedError = (AlertDescription.illegal_parameter, "Suspicious A value") #Calculate u u = makeU(N, A, B) #Calculate premaster secret S = powMod((A * powMod(v,u,N)) % N, b, N) premasterSecret = numberToBytes(S) #If we've selected an RSA suite, exchange keys and calculate #premaster secret: elif cipherSuite in CipherSuite.rsaSuites: #Send ServerHello, Certificate[, CertificateRequest], #ServerHelloDone msgs = [] msgs.append(ServerHello().create(self.version, serverRandom, sessionID, cipherSuite, certificateType)) msgs.append(Certificate(certificateType).create(serverCertChain)) if reqCert: msgs.append(CertificateRequest()) msgs.append(ServerHelloDone()) for result in self._sendMsgs(msgs): yield result #From here on, the client's messages must have the right version self._versionCheck = True #Get [Certificate,] (if was requested) if reqCert: if self.version == (3,0): for result in self._getMsg((ContentType.handshake, ContentType.alert), HandshakeType.certificate, certificateType): if result in (0,1): yield result else: break msg = result if isinstance(msg, Alert): #If it's not a no_certificate alert, re-raise alert = msg if alert.description != \ AlertDescription.no_certificate: self._shutdown(False) raise TLSRemoteAlert(alert) elif isinstance(msg, Certificate): clientCertificate = msg if clientCertificate.certChain and \ clientCertificate.certChain.getNumCerts()!=0: clientCertChain = clientCertificate.certChain else: raise AssertionError() elif self.version in ((3,1), (3,2)): for result in self._getMsg(ContentType.handshake, HandshakeType.certificate, certificateType): if result in (0,1): yield result else: break clientCertificate = result if clientCertificate.certChain and \ clientCertificate.certChain.getNumCerts()!=0: clientCertChain = clientCertificate.certChain else: raise AssertionError() #Get ClientKeyExchange for result in self._getMsg(ContentType.handshake, HandshakeType.client_key_exchange, cipherSuite): if result in (0,1): yield result else: break clientKeyExchange = result #Decrypt ClientKeyExchange premasterSecret = privateKey.decrypt(\ clientKeyExchange.encryptedPreMasterSecret) randomPreMasterSecret = getRandomBytes(48) versionCheck = (premasterSecret[0], premasterSecret[1]) if not premasterSecret: premasterSecret = randomPreMasterSecret elif len(premasterSecret)!=48: premasterSecret = randomPreMasterSecret elif versionCheck != clientHello.client_version: if versionCheck != self.version: #Tolerate buggy IE clients premasterSecret = randomPreMasterSecret #Get and check CertificateVerify, if relevant if clientCertChain: if self.version == (3,0): #Create a temporary session object, just for the purpose #of checking the CertificateVerify session = Session() session._calcMasterSecret(self.version, premasterSecret, clientRandom, serverRandom) verifyBytes = self._calcSSLHandshakeHash(\ session.masterSecret, "") elif self.version in ((3,1), (3,2)): verifyBytes = stringToBytes(self._handshake_md5.digest() +\ self._handshake_sha.digest()) for result in self._getMsg(ContentType.handshake, HandshakeType.certificate_verify): if result in (0,1): yield result else: break certificateVerify = result publicKey = clientCertChain.getEndEntityPublicKey() if len(publicKey) < settings.minKeySize: postFinishedError = (AlertDescription.handshake_failure, "Client's public key too small: %d" % len(publicKey)) if len(publicKey) > settings.maxKeySize: postFinishedError = (AlertDescription.handshake_failure, "Client's public key too large: %d" % len(publicKey)) if not publicKey.verify(certificateVerify.signature, verifyBytes): postFinishedError = (AlertDescription.decrypt_error, "Signature failed to verify") #Create the session object self.session = Session() self.session._calcMasterSecret(self.version, premasterSecret, clientRandom, serverRandom) self.session.sessionID = sessionID self.session.cipherSuite = cipherSuite self.session.srpUsername = self.allegedSrpUsername self.session.clientCertChain = clientCertChain self.session.serverCertChain = serverCertChain #Calculate pending connection states self._calcPendingStates(clientRandom, serverRandom, settings.cipherImplementations) #Exchange ChangeCipherSpec and Finished messages for result in self._getFinished(): yield result #If we were holding a post-finished error until receiving the client #finished message, send it now. We delay the call until this point #because calling sendError() throws an exception, and our caller might #shut down the socket upon receiving the exception. If he did, and the #client was still sending its ChangeCipherSpec or Finished messages, it #would cause a socket error on the client side. This is a lot of #consideration to show to misbehaving clients, but this would also #cause problems with fault-testing. if postFinishedError: for result in self._sendError(*postFinishedError): yield result for result in self._sendFinished(): yield result #Add the session object to the session cache if sessionCache and sessionID: sessionCache[bytesToString(sessionID)] = self.session #Mark the connection as open self.session._setResumable(True) self._handshakeDone(resumed=False) def _handshakeWrapperAsync(self, handshaker, checker): if not self.fault: try: for result in handshaker: yield result if checker: try: checker(self) except TLSAuthenticationError: alert = Alert().create(AlertDescription.close_notify, AlertLevel.fatal) for result in self._sendMsg(alert): yield result raise except: self._shutdown(False) raise else: try: for result in handshaker: yield result if checker: try: checker(self) except TLSAuthenticationError: alert = Alert().create(AlertDescription.close_notify, AlertLevel.fatal) for result in self._sendMsg(alert): yield result raise except socket.error, e: raise TLSFaultError("socket error!") except TLSAbruptCloseError, e: raise TLSFaultError("abrupt close error!") except TLSAlert, alert: if alert.description not in Fault.faultAlerts[self.fault]: raise TLSFaultError(str(alert)) else: pass except: self._shutdown(False) raise else: raise TLSFaultError("No error!") def _getKeyFromChain(self, certificate, settings): #Get and check cert chain from the Certificate message certChain = certificate.certChain if not certChain or certChain.getNumCerts() == 0: for result in self._sendError(AlertDescription.illegal_parameter, "Other party sent a Certificate message without "\ "certificates"): yield result #Get and check public key from the cert chain publicKey = certChain.getEndEntityPublicKey() if len(publicKey) < settings.minKeySize: for result in self._sendError(AlertDescription.handshake_failure, "Other party's public key too small: %d" % len(publicKey)): yield result if len(publicKey) > settings.maxKeySize: for result in self._sendError(AlertDescription.handshake_failure, "Other party's public key too large: %d" % len(publicKey)): yield result yield publicKey, certChain