class Client(Thread):
def __init__(self,
connectionManager,
remoteNick,
sendMessageCallback,
recvMessageCallback,
handshakeDoneCallback,
smpRequestCallback,
errorCallback,
initiateHandkshakeOnStart=False):
Thread.__init__(self)
self.daemon = True
self.connectionManager = connectionManager
self.remoteNick = remoteNick
self.sendMessageCallback = sendMessageCallback
self.recvMessageCallback = recvMessageCallback
self.handshakeDoneCallback = handshakeDoneCallback
self.smpRequestCallback = smpRequestCallback
self.errorCallback = errorCallback
self.initiateHandkshakeOnStart = initiateHandkshakeOnStart
self.incomingMessageNum = 0
self.outgoingMessageNum = 0
self.isEncrypted = False
self.wasHandshakeDone = False
self.messageQueue = queue.Queue()
self.crypto = Crypto()
self.crypto.generateDHKey()
self.smp = None
def sendChatMessage(self, text):
self.sendMessage(constants.COMMAND_MSG, text)
def sendTypingMessage(self, status):
self.sendMessage(constants.COMMAND_TYPING, str(status))
def sendMessage(self, command, payload=None):
message = Message(clientCommand=command, destNick=self.remoteNick)
# Encrypt all outgoing data
if payload is not None and self.isEncrypted:
payload = self.crypto.aesEncrypt(payload)
message.setEncryptedPayload(payload)
# Generate and set the HMAC for the message
message.setBinaryHmac(self.crypto.generateHmac(payload))
# Encrypt the message number of the message
message.setBinaryMessageNum(
self.crypto.aesEncrypt(str(self.outgoingMessageNum)))
self.outgoingMessageNum += 1
else:
message.payload = payload
self.sendMessageCallback(message)
def postMessage(self, message):
self.messageQueue.put(message)
def initiateSMP(self, question, answer):
self.sendMessage(constants.COMMAND_SMP_0, question)
self.smp = SMP(answer)
buffer = self.smp.step1()
self.sendMessage(constants.COMMAND_SMP_1, buffer)
def respondSMP(self, answer):
self.smp = SMP(answer)
self.__doSMPStep1(self.smpStep1)
def run(self):
if self.initiateHandkshakeOnStart:
self.__initiateHandshake()
else:
self.__doHandshake()
if not self.wasHandshakeDone:
return
while True:
message = self.messageQueue.get()
command = message.clientCommand
payload = message.payload
# Check if the client requested to end the connection
if command == constants.COMMAND_END:
self.connectionManager.destroyClient(self.remoteNick)
self.errorCallback(self.remoteNick,
errors.ERR_CONNECTION_ENDED)
return
# Ensure we got a valid command
elif self.wasHandshakeDone and command not in constants.LOOP_COMMANDS:
self.connectionManager.destroyClient(self.remoteNick)
self.errorCallback(self.remoteNick, errors.ERR_INVALID_COMMAND)
return
# Decrypt the incoming data
payload = self.__getDecryptedPayload(message)
self.messageQueue.task_done()
# Handle SMP commands specially
if command in constants.SMP_COMMANDS:
self.__handleSMPCommand(command, payload)
else:
self.recvMessageCallback(command, message.sourceNick, payload)
def connect(self):
self.__initiateHandshake()
def disconnect(self):
try:
self.sendMessage(constants.COMMAND_END)
except:
pass
def __doHandshake(self):
try:
# The caller of this function (should) checks for the initial HELO command
# Send the ready command
self.sendMessage(constants.COMMAND_REDY)
# Receive the client's public key
clientPublicKey = self.__getHandshakeMessagePayload(
constants.COMMAND_PUBLIC_KEY)
self.crypto.computeDHSecret(int(base64.b64decode(clientPublicKey)))
# Send our public key
publicKey = base64.b64encode(str(self.crypto.getDHPubKey()))
self.sendMessage(constants.COMMAND_PUBLIC_KEY, publicKey)
# Switch to AES encryption for the remainder of the connection
self.isEncrypted = True
self.wasHandshakeDone = True
self.handshakeDoneCallback(self.remoteNick)
except exceptions.ProtocolEnd:
self.disconnect()
self.connectionManager.destroyClient(self.remoteNick)
except (exceptions.ProtocolError, exceptions.CryptoError) as e:
self.__handleHandshakeError(e)
def __initiateHandshake(self):
try:
# Send the hello command
self.sendMessage(constants.COMMAND_HELO)
# Receive the redy command
self.__getHandshakeMessagePayload(constants.COMMAND_REDY)
# Send our public key
publicKey = base64.b64encode(str(self.crypto.getDHPubKey()))
self.sendMessage(constants.COMMAND_PUBLIC_KEY, publicKey)
# Receive the client's public key
clientPublicKey = self.__getHandshakeMessagePayload(
constants.COMMAND_PUBLIC_KEY)
self.crypto.computeDHSecret(int(base64.b64decode(clientPublicKey)))
# Switch to AES encryption for the remainder of the connection
self.isEncrypted = True
self.wasHandshakeDone = True
self.handshakeDoneCallback(self.remoteNick)
except exceptions.ProtocolEnd:
self.disconnect()
self.connectionManager.destroyClient(self.remoteNick)
except (exceptions.ProtocolError, exceptions.CryptoError) as e:
self.__handleHandshakeError(e)
def __getHandshakeMessagePayload(self, expectedCommand):
message = self.messageQueue.get()
if message.clientCommand != expectedCommand:
if message.clientCommand == constants.COMMAND_END:
raise exceptions.ProtocolEnd
elif message.clientCommand == constants.COMMAND_REJECT:
raise exceptions.ProtocolError(
errno=errors.ERR_CONNECTION_REJECTED)
else:
raise exceptions.ProtocolError(errno=errors.ERR_BAD_HANDSHAKE)
payload = self.__getDecryptedPayload(message)
self.messageQueue.task_done()
return payload
def __getDecryptedPayload(self, message):
if self.isEncrypted:
payload = message.getEncryptedPayloadAsBinaryString()
encryptedMessageNumber = message.getMessageNumAsBinaryString()
# Check the HMAC
if not self.__verifyHmac(message.hmac, payload):
self.errorCallback(message.sourceNick, errors.ERR_BAD_HMAC)
raise exceptions.CryptoError(errno=errors.BAD_HMAC)
try:
# Check the message number
messageNumber = int(
self.crypto.aesDecrypt(encryptedMessageNumber))
# If the message number is less than what we're expecting, the message is being replayed
if self.incomingMessageNum > messageNumber:
raise exceptions.ProtocolError(
errno=errors.ERR_MESSAGE_REPLAY)
# If the message number is greater than what we're expecting, messages are being deleted
elif self.incomingMessageNum < messageNumber:
raise exceptions.ProtocolError(
errno=errors.ERR_MESSAGE_DELETION)
self.incomingMessageNum += 1
# Decrypt the payload
payload = self.crypto.aesDecrypt(payload)
except exceptions.CryptoError as ce:
self.errorCallback(message.sourceNick, errors.ERR_BAD_DECRYPT)
raise ce
else:
payload = message.payload
return payload
def __verifyHmac(self, givenHmac, payload):
generatedHmac = self.crypto.generateHmac(payload)
return utils.secureStrcmp(generatedHmac, base64.b64decode(givenHmac))
def __handleSMPCommand(self, command, payload):
try:
if command == constants.COMMAND_SMP_0:
# Fire the SMP request callback with the given question
self.smpRequestCallback(constants.SMP_CALLBACK_REQUEST,
self.remoteNick, payload)
elif command == constants.COMMAND_SMP_1:
# If there's already an smp object, go ahead to step 1.
# Otherwise, save the payload until we have an answer from the user to respond with
if self.smp:
self.__doSMPStep1(payload)
else:
self.smpStep1 = payload
elif command == constants.COMMAND_SMP_2:
self.__doSMPStep2(payload)
elif command == constants.COMMAND_SMP_3:
self.__doSMPStep3(payload)
elif command == constants.COMMAND_SMP_4:
self.__doSMPStep4(payload)
else:
# This shouldn't happen
raise exceptions.CryptoError(errno=errors.ERR_SMP_CHECK_FAILED)
except exceptions.CryptoError as ce:
self.smpRequestCallback(constants.SMP_CALLBACK_ERROR,
self.remoteNick, '', ce.errno)
def __doSMPStep1(self, payload):
buffer = self.smp.step2(payload)
self.sendMessage(constants.COMMAND_SMP_2, buffer)
def __doSMPStep2(self, payload):
buffer = self.smp.step3(payload)
self.sendMessage(constants.COMMAND_SMP_3, buffer)
def __doSMPStep3(self, payload):
buffer = self.smp.step4(payload)
self.sendMessage(constants.COMMAND_SMP_4, buffer)
# Destroy the SMP object now that we're done
self.smp = None
def __doSMPStep4(self, payload):
self.smp.step5(payload)
if self.__checkSMP():
self.smpRequestCallback(constants.SMP_CALLBACK_COMPLETE,
self.remoteNick)
# Destroy the SMP object now that we're done
self.smp = None
def __checkSMP(self):
if not self.smp.match:
raise exceptions.CryptoError(errno=errors.ERR_SMP_MATCH_FAILED)
return True
def __handleHandshakeError(self, exception):
self.errorCallback(self.remoteNick, exception.errno)
# For all errors except the connection being rejected, tell the client there was an error
if exception.errno != errors.ERR_CONNECTION_REJECTED:
self.sendMessage(constants.COMMAND_ERR)
else:
self.connectionManager.destroyClient(self.remoteNick)
class Client(Thread):
def __init__(self, connectionManager, remoteNick, sendMessageCallback, recvMessageCallback, handshakeDoneCallback, smpRequestCallback, errorCallback, initiateHandkshakeOnStart=False):
Thread.__init__(self)
self.daemon = True
self.connectionManager = connectionManager
self.remoteNick = remoteNick
self.sendMessageCallback = sendMessageCallback
self.recvMessageCallback = recvMessageCallback
self.handshakeDoneCallback = handshakeDoneCallback
self.smpRequestCallback = smpRequestCallback
self.errorCallback = errorCallback
self.initiateHandkshakeOnStart = initiateHandkshakeOnStart
self.incomingMessageNum = 0
self.outgoingMessageNum = 0
self.isEncrypted = False
self.wasHandshakeDone = False
self.messageQueue = Queue.Queue()
self.crypto = Crypto()
self.crypto.generateDHKey()
self.smp = None
def sendChatMessage(self, text):
self.sendMessage(constants.COMMAND_MSG, text)
def sendTypingMessage(self, status):
self.sendMessage(constants.COMMAND_TYPING, str(status))
def sendMessage(self, command, payload=None):
message = Message(clientCommand=command, destNick=self.remoteNick)
# Encrypt all outgoing data
if payload is not None and self.isEncrypted:
payload = self.crypto.aesEncrypt(payload)
message.setEncryptedPayload(payload)
# Generate and set the HMAC for the message
message.setBinaryHmac(self.crypto.generateHmac(payload))
# Encrypt the message number of the message
message.setBinaryMessageNum(self.crypto.aesEncrypt(str(self.outgoingMessageNum)))
self.outgoingMessageNum += 1
else:
message.payload = payload
self.sendMessageCallback(message)
def postMessage(self, message):
self.messageQueue.put(message)
def initiateSMP(self, question, answer):
self.sendMessage(constants.COMMAND_SMP_0, question)
self.smp = SMP(answer)
buffer = self.smp.step1()
self.sendMessage(constants.COMMAND_SMP_1, buffer)
def respondSMP(self, answer):
self.smp = SMP(answer)
self.__doSMPStep1(self.smpStep1)
def run(self):
if self.initiateHandkshakeOnStart:
self.__initiateHandshake()
else:
self.__doHandshake()
if not self.wasHandshakeDone:
return
while True:
message = self.messageQueue.get()
command = message.clientCommand
payload = message.payload
# Check if the client requested to end the connection
if command == constants.COMMAND_END:
self.connectionManager.destroyClient(self.remoteNick)
self.errorCallback(self.remoteNick, errors.ERR_CONNECTION_ENDED)
return
# Ensure we got a valid command
elif self.wasHandshakeDone and command not in constants.LOOP_COMMANDS:
self.connectionManager.destroyClient(self.remoteNick)
self.errorCallback(self.remoteNick, errors.ERR_INVALID_COMMAND)
return
# Decrypt the incoming data
payload = self.__getDecryptedPayload(message)
self.messageQueue.task_done()
# Handle SMP commands specially
if command in constants.SMP_COMMANDS:
self.__handleSMPCommand(command, payload)
else:
self.recvMessageCallback(command, message.sourceNick, payload)
def connect(self):
self.__initiateHandshake()
def disconnect(self):
try:
self.sendMessage(constants.COMMAND_END)
except:
pass
def __doHandshake(self):
try:
# The caller of this function (should) checks for the initial HELO command
# Send the ready command
self.sendMessage(constants.COMMAND_REDY)
# Receive the client's public key
clientPublicKey = self.__getHandshakeMessagePayload(constants.COMMAND_PUBLIC_KEY)
self.crypto.computeDHSecret(long(base64.b64decode(clientPublicKey)))
# Send our public key
publicKey = base64.b64encode(str(self.crypto.getDHPubKey()))
self.sendMessage(constants.COMMAND_PUBLIC_KEY, publicKey)
# Switch to AES encryption for the remainder of the connection
self.isEncrypted = True
self.wasHandshakeDone = True
self.handshakeDoneCallback(self.remoteNick)
except exceptions.ProtocolEnd:
self.disconnect()
self.connectionManager.destroyClient(self.remoteNick)
except (exceptions.ProtocolError, exceptions.CryptoError) as e:
self.__handleHandshakeError(e)
def __initiateHandshake(self):
try:
# Send the hello command
self.sendMessage(constants.COMMAND_HELO)
# Receive the redy command
self.__getHandshakeMessagePayload(constants.COMMAND_REDY)
# Send our public key
publicKey = base64.b64encode(str(self.crypto.getDHPubKey()))
self.sendMessage(constants.COMMAND_PUBLIC_KEY, publicKey)
# Receive the client's public key
clientPublicKey = self.__getHandshakeMessagePayload(constants.COMMAND_PUBLIC_KEY)
self.crypto.computeDHSecret(long(base64.b64decode(clientPublicKey)))
# Switch to AES encryption for the remainder of the connection
self.isEncrypted = True
self.wasHandshakeDone = True
self.handshakeDoneCallback(self.remoteNick)
except exceptions.ProtocolEnd:
self.disconnect()
self.connectionManager.destroyClient(self.remoteNick)
except (exceptions.ProtocolError, exceptions.CryptoError) as e:
self.__handleHandshakeError(e)
def __getHandshakeMessagePayload(self, expectedCommand):
message = self.messageQueue.get()
if message.clientCommand != expectedCommand:
if message.clientCommand == constants.COMMAND_END:
raise exceptions.ProtocolEnd
elif message.clientCommand == constants.COMMAND_REJECT:
raise exceptions.ProtocolError(errno=errors.ERR_CONNECTION_REJECTED)
else:
raise exceptions.ProtocolError(errno=errors.ERR_BAD_HANDSHAKE)
payload = self.__getDecryptedPayload(message)
self.messageQueue.task_done()
return payload
def __getDecryptedPayload(self, message):
if self.isEncrypted:
payload = message.getEncryptedPayloadAsBinaryString()
encryptedMessageNumber = message.getMessageNumAsBinaryString()
# Check the HMAC
if not self.__verifyHmac(message.hmac, payload):
self.errorCallback(message.sourceNick, errors.ERR_BAD_HMAC)
raise exceptions.CryptoError(errno=errors.BAD_HMAC)
try:
# Check the message number
messageNumber = int(self.crypto.aesDecrypt(encryptedMessageNumber))
# If the message number is less than what we're expecting, the message is being replayed
if self.incomingMessageNum > messageNumber:
raise exceptions.ProtocolError(errno=errors.ERR_MESSAGE_REPLAY)
# If the message number is greater than what we're expecting, messages are being deleted
elif self.incomingMessageNum < messageNumber:
raise exceptions.ProtocolError(errno=errors.ERR_MESSAGE_DELETION)
self.incomingMessageNum += 1
# Decrypt the payload
payload = self.crypto.aesDecrypt(payload)
except exceptions.CryptoError as ce:
self.errorCallback(message.sourceNick, errors.ERR_BAD_DECRYPT)
raise ce
else:
payload = message.payload
return payload
def __verifyHmac(self, givenHmac, payload):
generatedHmac = self.crypto.generateHmac(payload)
return utils.secureStrcmp(generatedHmac, base64.b64decode(givenHmac))
def __handleSMPCommand(self, command, payload):
try:
if command == constants.COMMAND_SMP_0:
# Fire the SMP request callback with the given question
self.smpRequestCallback(constants.SMP_CALLBACK_REQUEST, self.remoteNick, payload)
elif command == constants.COMMAND_SMP_1:
# If there's already an smp object, go ahead to step 1.
# Otherwise, save the payload until we have an answer from the user to respond with
if self.smp:
self.__doSMPStep1(payload)
else:
self.smpStep1 = payload
elif command == constants.COMMAND_SMP_2:
self.__doSMPStep2(payload)
elif command == constants.COMMAND_SMP_3:
self.__doSMPStep3(payload)
elif command == constants.COMMAND_SMP_4:
self.__doSMPStep4(payload)
else:
# This shouldn't happen
raise exceptions.CryptoError(errno=errors.ERR_SMP_CHECK_FAILED)
except exceptions.CryptoError as ce:
self.smpRequestCallback(constants.SMP_CALLBACK_ERROR, self.remoteNick, '', ce.errno)
def __doSMPStep1(self, payload):
buffer = self.smp.step2(payload)
self.sendMessage(constants.COMMAND_SMP_2, buffer)
def __doSMPStep2(self, payload):
buffer = self.smp.step3(payload)
self.sendMessage(constants.COMMAND_SMP_3, buffer)
def __doSMPStep3(self, payload):
buffer = self.smp.step4(payload)
self.sendMessage(constants.COMMAND_SMP_4, buffer)
# Destroy the SMP object now that we're done
self.smp = None
def __doSMPStep4(self, payload):
self.smp.step5(payload)
if self.__checkSMP():
self.smpRequestCallback(constants.SMP_CALLBACK_COMPLETE, self.remoteNick)
# Destroy the SMP object now that we're done
self.smp = None
def __checkSMP(self):
if not self.smp.match:
raise exceptions.CryptoError(errno=errors.ERR_SMP_MATCH_FAILED)
return True
def __handleHandshakeError(self, exception):
self.errorCallback(self.remoteNick, exception.errno)
# For all errors except the connection being rejected, tell the client there was an error
if exception.errno != errors.ERR_CONNECTION_REJECTED:
self.sendMessage(constants.COMMAND_ERR)
else:
self.connectionManager.destroyClient(self.remoteNick)