Config

client/client.py

@@ -11,6 +11,8 @@ from netwrapper import NetWrapper
 ABSOLUTE_PATH = os.path.abspath(os.path.dirname(sys.argv[0]))
 DOWNLOAD_LOCATION = ABSOLUTE_PATH + os.path.sep + 'download' + os.path.sep
 CONFIG_LOCATION = ABSOLUTE_PATH + os.path.sep + 'config' + os.path.sep + 'config.txt'
+PASSPHRASE = ''
+SERVER_ADDRESS = ''
 LOGGED_IN = False
 
 
@@ -50,10 +52,11 @@ def loadAddress() -> str:
 def printCommand():
     print('\nInvalid command! Available commands:\n' +
           '     Create directory                        -> MKD <directory name> \n' +
-          '     Remove directory                        -> RMV <directory name> \n' +
+          '     Remove directory                        -> RMD <directory name> \n' +
           '     Get current directory                   -> GWD \n' +
           '     Change current directory                -> CWD <path> \n' +
           '     List content of current directory       -> LST \n' +
+          '     Remove file from current directory      -> RMF <filename> \n' +
           '     Upload file to current directory        -> UPL <filename> \n' +
           '     Download file from current directory    -> DNL <filename> \n' +
           '     Login                                   -> LIN <username> <password> \n' +
@@ -67,7 +70,7 @@ def printCommandsWihtoutLogin():
 
 
 try:
-    opts, args = getopt.getopt(sys.argv[1:], 'hp:')
+    opts, args = getopt.getopt(sys.argv[1:], 'hp:s:')
 except getopt.GetoptError:
     print('Error: Unknown option detected.')
     sys.exit(1)
@@ -76,10 +79,13 @@ for opt, arg in opts:
     if opt in '-p':
         PASSPHRASE = arg
 
+    if opt in '-s':
+        SERVER_ADDRESS = arg
+
 if PASSPHRASE == '':
     print('Key required to start client!')
     print('Usage:')
-    print('  client.py -p <passphrase>')
+    print('  client.py -p <passphrase> -s <server_address>')
     sys.exit(1)
 
 if not os.path.isfile(CONFIG_LOCATION) or os.stat(CONFIG_LOCATION).st_size == 0:
@@ -89,6 +95,9 @@ if not os.path.isfile(CONFIG_LOCATION) or os.stat(CONFIG_LOCATION).st_size == 0:
 SERVER_PUBLIC_KEY = loadPublicKey()
 CLIENT_PRIVATE_KEY = loadPrivateKey(PASSPHRASE)
 CLIENT_ADDRESS = loadAddress()
+LOGGED_IN = False
+
+network = NetWrapper(CLIENT_PRIVATE_KEY, CLIENT_ADDRESS, SERVER_PUBLIC_KEY, serverAddr=SERVER_ADDRESS)
 
 while True:
     command = input("Type a command:")
@@ -99,15 +108,24 @@ while True:
             print("Invalid command format!")
             continue
 
-        if separatedCommand[0] == 'LIN' and len(separatedCommand) == 3:
-            network = NetWrapper(CLIENT_PRIVATE_KEY, CLIENT_ADDRESS, separatedCommand[1], SERVER_PUBLIC_KEY)
-            try:
-                network.connectToServer()
-            except Exception as e:
-                print("Error: "+str(e))
+        if not LOGGED_IN:
+            if separatedCommand[0] == 'LIN' and len(separatedCommand) == 3:
+                network.username = separatedCommand[1]
+                try:
+                    network.connectToServer(separatedCommand[2])
+                    response = network.recieveMessage().decode('UTF-8')
+                    print(response)
+                    if response == 'OK':
+                        LOGGED_IN = True
+                    else:
+                        LOGGED_IN = False
+                except Exception as e:
+                    print("Error: "+str(e))
+                    LOGGED_IN = False
                 continue
-            LOGGED_IN = True
-            continue
+        else:
+            print('You are already logged in!')
+
 
         if separatedCommand[0] == 'EXIT':
             sys.exit(1)
@@ -119,6 +137,7 @@ while True:
         if separatedCommand[0] == 'LOUT' and len(separatedCommand) == 1:
             network.sendMessage(command.encode('UTF-8'))
             print(network.recieveMessage().decode('UTF-8'))
+            LOGGED_IN = False
             continue
 
         if separatedCommand[0] == 'MKD' and len(separatedCommand) == 2:
@@ -146,13 +165,18 @@ while True:
             print(network.recieveMessage().decode('UTF-8'))
             continue
 
+        if separatedCommand[0] == 'RMF' and len(separatedCommand) == 2:
+            network.sendMessage(command.encode('UTF-8'))
+            print(network.recieveMessage().decode('UTF-8'))
+            continue
+
         if separatedCommand[0] == 'UPL' and len(separatedCommand) == 2:
             if os.path.isfile(separatedCommand[1]):
                 cmd = 'UPL ' + separatedCommand[1].split(os.path.sep)[-1]
                 network.sendMessage(cmd.encode('UTF-8'))
 
                 with open(separatedCommand[1], "rb") as file:
-                    network.sendMessage(file.readlines())
+                    network.sendMessage(file.read())
 
                 network.sendMessage('EOF'.encode('UTF-8'))
                 response = network.recieveMessage().decode('UTF-8')
@@ -166,12 +190,15 @@ while True:
             dnlFilename = separatedCommand[1].split(os.path.sep)[-1]
             cmd = 'DNL ' + dnlFilename
             network.sendMessage(cmd.encode('UTF-8'))
-            file = network.recieveMessage().decode('UTF-8')
+            filecontent = network.recieveMessage()
             response = network.recieveMessage().decode('UTF-8')
 
-            if response == 'OK':
+            print(DOWNLOAD_LOCATION + dnlFilename)
+
+            if response == 'EOF':
                 with open(DOWNLOAD_LOCATION + dnlFilename, "wb+") as file:
-                    file.writelines(file)
+                    file.write(filecontent)
+                print('OK')
             else:
                 print(response)
 
@@ -181,3 +208,4 @@ while True:
 
     except Exception as e:
         print('Error: ' + str(e))
+        continue

client/main.py

@@ -1,4 +0,0 @@
-#!/usr/bin/env python3
-
-if __name__ == '__main__':
-    print("hi")

client/netwrapper.py

@@ -4,17 +4,17 @@ import string
 import json
 from base64 import b64encode, b64decode
 import pyDH
-from Crypto.Cipher import ChaCha20, PKCS1_OAEP
+from Crypto.Hash import SHA512
+from Crypto.Cipher import ChaCha20_Poly1305, PKCS1_OAEP
 from Crypto.PublicKey.RSA import RsaKey
-from Crypto.Random import get_random_bytes
+from Crypto.Signature import pkcs1_15
 
 from netsim import network_interface
 
 
 class NetWrapper:
-    def __init__(self, privateKey: RsaKey, clientAddress: str, username: str, serverPubKey: RsaKey,
+    def __init__(self, privateKey: RsaKey, clientAddress: str, serverPubKey: RsaKey, username: str = "",
                  serverAddr: str = 'A'):
-        # Create network_interface:  network_interface(path, addr) path root is shared with network / addr is own address
         self.network = network_interface('./../../netsim/network/', clientAddress)
         self.serverAddr = serverAddr
         self.username = username
@@ -22,106 +22,138 @@ class NetWrapper:
         self.serverPubKey = serverPubKey
         self.cipherkey = "".encode('UTF-8')
 
-
-    def randomStringGenerator(self, str_size: int = 128,
+    def randomStringGenerator(self, str_size: int = 256,
                               allowed_chars: str = string.ascii_letters + string.punctuation) -> str:
         return ''.join(random.choice(allowed_chars) for x in range(str_size))
 
+    def ecryptRSAMessage(self, message: bytes) -> bytes:
+        cipher_rsa = PKCS1_OAEP.new(self.serverPubKey)
+        encrypted_msg = cipher_rsa.encrypt(message)
+        return encrypted_msg
+
+    def signRSAHeader(self, type: str, extradata: dict) -> (bytes, bytes):
+        mandatory = {'type': type, 'source': self.network.own_addr}
+        header = json.dumps({**mandatory, **extradata}).encode('UTF-8')
+        h = SHA512.new(header)
+        headersignature = pkcs1_15.new(self.privateKey).sign(h)
+        return header, headersignature
+
+    def verifyRSAHeaderSignature(self, header: bytes, headersignature: bytes) -> bool:
+        h = SHA512.new(header)
+        try:
+            pkcs1_15.new(self.serverPubKey).verify(h, headersignature)
+            return True
+        except Exception:
+            return False
+
+    def decryptRSAMessage(self, message: bytes) -> bytes:
+        cipher_rsa = PKCS1_OAEP.new(self.privateKey)
+        return cipher_rsa.decrypt(message)
+
+    def recieveAndUnpackRSAMessage(self) -> (str, str):
+        status, msg = self.network.receive_msg(blocking=True)
+        if not status:
+            raise Exception('Network error during connection.')
+        decodedmsg = json.loads(msg.decode('UTF-8'))
+        return decodedmsg, json.loads(b64decode(decodedmsg['header']).decode('UTF-8'))
 
     def identifyServer(self) -> bool:
         randommsg = self.randomStringGenerator()
-        cipher_rsa = PKCS1_OAEP.new(self.serverPubKey)
+        encrypted_msg = self.ecryptRSAMessage(randommsg.encode('UTF-8'))
+        header, headersignature = self.signRSAHeader('IDY', {'username': self.username})
         identMsg = json.dumps(
-            {'type': 'IDY', 'source': self.network.own_addr, 'username': self.username,
-             'message': b64encode(cipher_rsa.encrypt(randommsg.encode('UTF-8'))).decode('ASCII')}).encode(
+            {'header': b64encode(header).decode('UTF-8'),
+             'message': b64encode(encrypted_msg).decode('UTF-8'),
+             'headersignature': b64encode(headersignature).decode('UTF-8')}).encode(
             'UTF-8')
         self.network.send_msg(self.serverAddr, identMsg)
-        returnJson = {'source': '', 'type': ''}
-        while not (returnJson['source'] == self.serverAddr and returnJson['type'] == 'IDY'):
-            status, msg = self.network.receive_msg(blocking=True)
-            if not status:
-                raise Exception('Network error during connection.')
-            returnJson = json.loads(msg.decode('UTF-8'))
-        cipher_rsa = PKCS1_OAEP.new(self.privateKey)
-        retmsg = cipher_rsa.decrypt(b64decode(returnJson['message'])).decode('UTF-8')
+        returnJson, header = self.recieveAndUnpackRSAMessage()
+        try:
+            if not self.verifyRSAHeaderSignature(b64decode(returnJson['header']),
+                                                 b64decode(returnJson['headersignature'])) or not (
+                    header['source'] == self.serverAddr and header['type'] == 'IDY'):
+                return False
+            retmsg = self.decryptRSAMessage(b64decode(returnJson['message'])).decode('UTF-8')
+        except Exception:
+            return False
         return retmsg == randommsg
 
-
-    def createEncryptedChannel(self):
+    def createEncryptedChannel(self) -> None:
         dh = pyDH.DiffieHellman()
-        cipher_rsa = PKCS1_OAEP.new(self.serverPubKey)
-        mypubkey = b64encode(cipher_rsa.encrypt(str(dh.gen_public_key()).encode('UTF-8'))).decode('ASCII')
-        jsonmsg = json.dumps({'type': 'DH', 'source': self.network.own_addr, 'message': mypubkey}).encode('UTF-8')
+        mypubkey = self.ecryptRSAMessage(str(dh.gen_public_key()).encode('UTF-8'))
+        header, headersignature = self.signRSAHeader("DH",{})
+        jsonmsg = json.dumps(
+            {'header': b64encode(header).decode('UTF-8'), 'headersignature': b64encode(headersignature).decode('UTF-8'),
+             'message':  b64encode(mypubkey).decode('UTF-8')}).encode('UTF-8')
         self.network.send_msg(self.serverAddr, jsonmsg)
-        decodedmsg = {'source': '', 'type': ''}
-        while not (decodedmsg['source'] == self.serverAddr and  decodedmsg['type'] == 'DH'):
-            status, msg = self.network.receive_msg(blocking=True)
-            if not status:
-                raise Exception('Network error during connection.')
-            decodedmsg = json.loads(msg.decode('UTF-8'))
-        cipher_rsa = PKCS1_OAEP.new(self.privateKey)
-        serverpubkey = int(cipher_rsa.decrypt(b64decode(decodedmsg['message'])).decode('UTF-8'))
-        self.cipherkey = dh.gen_shared_key(serverpubkey).encode('UTF-8')
+        decodedmsg, header = self.recieveAndUnpackRSAMessage()
+        if not self.verifyRSAHeaderSignature(b64decode(decodedmsg['header']),
+                                             b64decode(decodedmsg['headersignature'])) or not (
+                header['source'] == self.serverAddr and header['type'] == 'DH'):
+            raise Exception('Header signature error')
+        serverpubkey = int(self.decryptRSAMessage(b64decode(decodedmsg['message'])).decode('UTF-8'))
+        cipherkey = dh.gen_shared_key(serverpubkey).encode('UTF-8')
+        hasher = SHA512.new()
+        hasher.update(cipherkey)
+        self.cipherkey = (hasher.hexdigest()[:32]).encode('UTF-8')
 
-
-    def authenticate(self, password: str):
+    def authenticate(self, password: str) -> None:
         message = f"LIN {self.username} {password}".encode('UTF-8')
-        cipher = ChaCha20.new(key=self.cipherkey, nonce=get_random_bytes(12))
-        ciphertext = cipher.encrypt(message)
-        nonce = b64encode(cipher.nonce).decode('ASCII')
-        ct = b64encode(ciphertext).decode('ASCII')
-        sendjson = json.dumps({'type': 'AUT', 'source': self.network.own_addr, 'nonce': nonce, 'message': ct}).encode(
-            'UTF-8')
-        self.network.send_msg(self.serverAddr, sendjson)
-        b64 = {'source': '', 'type': ''}
-        while not (b64['source'] == self.serverAddr and  b64['type'] == 'AUT'):
-            status, msg = self.network.receive_msg(blocking=True)
-            if not status:
-                raise Exception('Network error during connection.')
-            b64 = json.loads(msg.decode('UTF-8'))
-        try:
-            retnonce = b64decode(b64['nonce'])
-            retciphertext = b64decode(b64['message'])
-            retcipher = ChaCha20.new(self.cipherkey, nonce=retnonce)
-            plaintext = retcipher.decrypt(retciphertext).decode('UTF-8')
-            if plaintext != "OK":
-                raise Exception('Authentication error')
-        except Exception:
-            print("Incorrect decryption")
+        self.sendTypedMessage(message, "AUT")
+        plaintext = self.recieveTypedMessage("AUT").decode('UTF-8')
+        if plaintext != "OK":
+            print("Authentication error")
 
-
-    def connectToServer(self):
+    def connectToServer(self, password: str) -> None:
+        if self.username == "":
+            raise Exception('Username is not initialized')
+        if password == "":
+            raise Exception('Passowrd may not be empty')
         identStatus = self.identifyServer()
         if not identStatus:
             raise Exception('Server identification faliure')
         self.createEncryptedChannel()
-        print('Please enter your password:')
-        pw = input()
-        self.authenticate(pw)
+        self.authenticate(password)
 
+    def sendMessage(self, message: bytes) -> None:
+        try:
+            self.sendTypedMessage(message, "CMD")
+        except Exception:
+            print("Could not send message")
 
-    def sendMessage(self, message: bytes):
-        cipher = ChaCha20.new(key=self.cipherkey, nonce=get_random_bytes(12))
-        ciphertext = cipher.encrypt(message)
-        nonce = b64encode(cipher.nonce).decode('ASCII')
-        ct = b64encode(ciphertext).decode('ASCII')
-        sendjson = json.dumps({'type': 'CMD', 'source': self.network.own_addr, 'nonce': nonce, 'message': ct}).encode(
+    def sendTypedMessage(self, message: bytes, type: str) -> None:
+        if not (type == "AUT" or type == "CMD"):
+            raise Exception('Unknown message type')
+        cipher = ChaCha20_Poly1305.new(key=self.cipherkey)
+        header = json.dumps({'type': type, 'source': self.network.own_addr}).encode('UTF-8')
+        cipher.update(header)
+        ciphertext, tag = cipher.encrypt_and_digest(message)
+        nonce = b64encode(cipher.nonce).decode('UTF-8')
+        ct = b64encode(ciphertext).decode('UTF-8')
+        sendjson = json.dumps({'header': b64encode(header).decode('UTF-8'), 'nonce': nonce, 'message': ct,
+                               'tag': b64encode(tag).decode('UTF-8')}).encode(
             'UTF-8')
         self.network.send_msg(self.serverAddr, sendjson)
 
-
     def recieveMessage(self) -> bytes:
-        b64 = {'source': '', 'type': ''}
-        while not (b64['source'] == self.serverAddr and b64['type'] == 'AUT'):
+        return self.recieveTypedMessage("CMD")
+
+    def recieveTypedMessage(self, type: str) -> bytes:
+        if not (type == "AUT" or type == "CMD"):
+            raise Exception('Unknown message type')
+        try:
             status, msg = self.network.receive_msg(blocking=True)
             if not status:
                 raise Exception('Network error during connection.')
             b64 = json.loads(msg.decode('UTF-8'))
-        try:
             retnonce = b64decode(b64['nonce'])
             retciphertext = b64decode(b64['message'])
-            retcipher = ChaCha20.new(key=self.cipherkey, nonce=retnonce)
-            plaintext = retcipher.decrypt(retciphertext)
+            retcipher = ChaCha20_Poly1305.new(key=self.cipherkey, nonce=retnonce)
+            retcipher.update(b64decode(b64['header']))
+            plaintext = retcipher.decrypt_and_verify(retciphertext, b64decode(b64['tag']))
+            retheader = json.loads(b64decode(b64['header']).decode('UTF-8'))
+            if not (retheader['source'] == self.serverAddr and retheader['type'] == type):
+                return "ERROR".encode('UTF-8')
             return plaintext
         except Exception:
             print("Incorrect decryption")