Authorizer und Passive Datenverbindung implementiert

fakeftp.py

@@ -1,6 +1,56 @@
 import SocketServer
+import threading
+import socket
+from random import randint
+
+class DataConnection:
+	def run(self, dchandler):
+		pass
+
+
+class PassiveDataConnection(DataConnection):
+	def __init__(self, port):
+		self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+		self.socket.bind(("",port))
+		threading.Thread(target=self.waitForConnection).start()
+
+	def waitForConnection(self):
+		self.socket.listen(1)
+		self.connection, _ = self.socket.accept()
+
+	def run(self, dchandler):
+		threading.Thread(target=self.runHandler, args=(dchandler,) ).start()
+
+	def runHandler(self, dchandler):
+		dchandler.handle(self.connection)
+		self.connection.close()
+
+class ActiveDataConnection(DataConnection):
+	def __init__(self, host, port):
+		self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+		self.socket.connect( (host,port) )
+
+	def run(self, dchandler):
+		threading.Thread(target=self.runHandler, args=(dchandler,)).start()
+
+	def runHandler(self, dchandler):
+		dchandler.handle(self.socket)
+		self.socket.close()
+
+class FailAuthorizer:
+	'''Default authorizer. Denys all logins'''
+	def authorize(self, username, password, handler):
+		return False
+
+class AnonymousAuthorizer:
+	def authorize(self, username, password, handler):
+		if username in ["ftp","anonymous"]:
+			return True
+		else:
+			return False
 
 class FTPMessage:
+	'''Parses and creates FTP Messages'''
 	def __init__(self,cmd,parameter):
 		self.cmd = cmd
 		self.parameter = parameter
@@ -22,50 +72,102 @@ class FTPMessage:
 			param = line[pos+1:]
 		return FTPMessage(cmd.upper(),param)
 
-class GeneralState:
-	@staticmethod
-	def handle(self, message):
+class QuitMessage(FTPMessage):
+	'''Message sent to client when client wants to disconnect'''
+	def __init__(self):
+		FTPMessage.__init__(self,"221","Goodbye.")
+
+class InvalidCommandMessage(FTPMessage):
+	'''Message sent to client when server received message it didn't understand'''
+	def __init__(self,cmd):
+		FTPMessage.__init__(self,"500","%s not understood" % cmd)
+
+class PasswordRequiredMessage(FTPMessage):
+	'''Message sent to client when it specified a username'''
+	def __init__(self,user):
+		FTPMessage.__init__(self,"331","Password required for %s" % user)
+
+class AuthorizationSuccessfulMessage(FTPMessage):
+	'''Message sent to client when authorization was successful'''
+	def __init__(self):
+		FTPMessage.__init__(self,"230","Welcome user.")
+
+class AuthorizationFailedMessage(FTPMessage):
+	'''Message sent to client when authorization failed'''
+	def __init__(self):
+		FTPMessage.__init__(self,"530","Login incorrect.")
+
+class WelcomeMessage(FTPMessage):
+	'''Message sent to client after client has connected'''
+	def __init__(self):
+		FTPMessage.__init__(self,"220","FTP Server ready")
+
+class EnteringPassiveModeMessage(FTPMessage):
+	def __init__(self,addrtuple):
+		FTPMessage.__init__(self,"227","Entering Passive Mode %s." % addrtuple)
+
+# Data Connection Handler
+class HeloHandler:
+	def handle(self, socket):
+		socket.send("Hello World")
+
+# State classes
+class State:
+	def process(self, handler, message):
+		pass
+
+class MainState(State):
+	def process(self, handler, message):
 		if message.cmd == "QUIT":
-			self.debug("Client wants to quit")
-			self.send(FTPMessage("221","Goodbye."))
-			self.handler.running = False
+			handler.send( QuitMessage() )
+			handler.running = False
 		else:
-			self.debug("Unknown command %s" % message.cmd)
-			self.send(FTPMessage("500", "%s not understood" % message.cmd ))
+			handler.send( InvalidCommandMessage(message.cmd) )
 
-class UserState:
-	@staticmethod
-	def handle(self, message):
+class NonAuthorizedState(MainState):
+	def process(self, handler, message):
 		if message.cmd == "USER":
-			self.debug("Initiating login for user %s" % message.parameter)
-			self.send(FTPMessage("331","Password required for %s" % message.parameter))
-			self.state = PassState
+			handler.user = message.parameter
+			handler.state = AuthorizingState()
+			handler.send( PasswordRequiredMessage(handler.user) )
 		else:
-			GeneralState.handle(self, message)
+			MainState.process(self, handler, message)
 
-class PassState:
-	@staticmethod
-	def handle(self, message):
+class AuthorizingState(MainState):
+	def process(self, handler, message):
 		if message.cmd == "PASS":
-			self.debug("Denying access with password %s" % message.parameter)
-			self.send(FTPMessage("530","Login incorrect."))
-			self.state = UserState
+			password = message.parameter
+			if handler.authorizer.authorize(handler.user, password, handler):
+				handler.debug("User login %s successful" % handler.user)
+				handler.state = AuthorizedState()
+				handler.send( AuthorizationSuccessfulMessage() )
+			else:
+				handler.debug("User login %s failed" % handler.user)
+				handler.state = NonAuthorizedState()
+				handler.send( AuthorizationFailedMessage() )
 		else:
-			GeneralState.handle(self, message)
+			MainState.process(self, handler, message)
 
-class FTPMessageHandler:
-	def __init__(self, handler):
-		self.state = UserState
-		self.handler = handler
+class AuthorizedState(MainState):
+	def addrtuple(self, ip, port):
+		b = ip.split(".")
+		b.append( str( (port >> 8) & 0xFF ) )
+		b.append( str( port & 0xFF ) )
+		return "(" + ",".join(b)+ ")"
 
-	def send(self,data):
-		return self.handler.request.send( str(data) )
-
-	def debug(self,text):
-		self.handler.debug(text)
-
-	def handle(self, message):
-		self.state.handle(self, message)
+	def process(self, handler, message):
+		if message.cmd == "PASV":
+			port = handler.createPassiveDataConnection()
+			handler.debug("Created passive data connection")
+			handler.send( EnteringPassiveModeMessage( self.addrtuple("127.0.0.1",port) ) )
+		elif message.cmd == "HELO":
+			handler.debug("Running Helo on data connection")
+			if handler.runDataConnection(HeloHandler()):
+				handler.debug("successful")
+			else:
+				handler.debug("failed")
+		else:
+			MainState.process(self, handler, message)
 
 class LineReader:
 	def __init__(self):
@@ -88,12 +190,33 @@ class FTPHandler(SocketServer.BaseRequestHandler):
 	def debug(self, text):
 		print ("[%s] " % self.client_address[0]) + text
 
+	def send(self, message):
+		self.request.send( str(message) )
+
+	def createPassiveDataConnection(self):
+		port = randint(60000,63000)
+		self.connection = PassiveDataConnection(port)
+		return port
+
+	def createActiveDataConnection(self,port):
+		self.connection = ActiveDataConnection(self.client_address[0],port)
+
+	def runDataConnection(self, dchandler):
+		if self.connection is None:
+			return False
+		else:
+			self.connection.run(dchandler)
+			self.connection = None
+			return True
+
 	def handle(self):
-		self.messagehandler = FTPMessageHandler(self)
+		self.connection = None
+
+		self.state = NonAuthorizedState()
 
 		self.debug("Client connected");
 
-		self.request.send(FTPMessage("220","FTP Server ready").generate())
+		self.send( WelcomeMessage() )
 
 		linereader = LineReader()
 
@@ -108,10 +231,13 @@ class FTPHandler(SocketServer.BaseRequestHandler):
 
 			for line in linereader.get_lines():
 				message = FTPMessage.parse(line)
-				self.messagehandler.handle(message)
+				self.state.process(self,message)
 
 		self.debug("Client disconnected")
 
-server = SocketServer.ThreadingTCPServer(("",1234),FTPHandler)
+handler = FTPHandler
+handler.authorizer = AnonymousAuthorizer()
+
+server = SocketServer.ThreadingTCPServer(("",1234),handler)
 
 server.serve_forever()