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 __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