class Client():
def __init__(self):
self.current_protocol = "SEP" # changed to FMP later
self.expected_incoming_msg_type = "RES_INIT"
self.ver = 1
self.NET_PATH = "./network"
self.FOLDER_PATH = "./client"
if (self.NET_PATH[-1] != '/') and (self.NET_PATH[-1] != '\\'):
self.NET_PATH += '/'
if (self.FOLDER_PATH[-1] != '/') and (self.FOLDER_PATH[-1] != '\\'):
self.FOLDER_PATH += '/'
self.DST_ADDR = None
self.OWN_ADDR = input('Type your own address: ') # Ex. A, B, or C
self.netif = network_interface(self.NET_PATH, self.OWN_ADDR)
self.protocols = Protocols()
self.timeout = 30
self.sleep_time = 0.1
self.session_key = None
self.client_prikey = None
self.client_pubkey = None
self.server_pubkey = None
#fmp seq num
self.seq_last_received = 0
self.seq_last_sent = 0
self.DATA_LOC = "my_data"
def clean_keys(self):
self.client_prikey = None
self.client_pubkey = None
self.server_pubkey = None
def load_client_prikey(self):
try:
key = open(
self.FOLDER_PATH + "private_keys/" + self.OWN_ADDR + ".pem",
"rb").read()
self.client_prikey = RSA.import_key(key)
except:
print("Error: could not load client private key")
def load_client_pubkey(self):
try:
key = open(
self.FOLDER_PATH + "public_keys/" + self.OWN_ADDR + ".pem",
"rb").read()
self.client_pubkey = RSA.import_key(key)
except:
print("Error: could not load client public key")
def load_server_pubkey(self):
try:
key = open(
self.FOLDER_PATH + "public_keys/" + self.DST_ADDR + ".pem",
"rb").read()
self.server_pubkey = RSA.import_key(key)
except:
print("Error: could not load server public key")
def fix_length(self, input_byte, desired_length):
if (len(input_byte) > desired_length):
print("Error fixing the length of byte")
return None
res = b""
for i in range(desired_length - len(input_byte)):
res += b"\x00"
res += input_byte
return res
def handle_options(self):
try:
opts, args = getopt.getopt(sys.argv[1:],
shortopts='hp:a',
longopts=['help', 'path=', 'addr='])
except getopt.GetoptError:
print('wrong options')
sys.exit(1)
def generate_nonce(self):
return secrets.token_bytes(32)
def SEP_ENC(self, ptext, key):
cipher_rsa = PKCS1_OAEP.new(key)
ctext = cipher_rsa.encrypt(ptext)
return ctext
def SEP_DEC(self, ctext, key):
cipher_rsa = PKCS1_OAEP.new(key)
ptext = cipher_rsa.decrypt(ctext)
return ptext
def SEP_SIGN(self, message, key):
h = SHA256.new(message)
signature = pkcs1_15.new(key).sign(h)
return signature
def SEP_GEN(self, ver, type_sep, type_msg, sender_id, recipient_id,
encrypted_content, sig_key):
msg = b""
msg += ver
msg += type_sep
msg += type_msg
msg += len(encrypted_content).to_bytes(length=5,
byteorder='big') #msg_len
msg += sender_id
msg += recipient_id
msg += encrypted_content
sig = self.SEP_SIGN(msg, sig_key)
#print("Generated sig: ")
#print(sig)
msg += sig
return msg
def SEP_REQ_INIT(self):
# generate SEP REQ_INIT
#header
ver = self.ver.to_bytes(length=1, byteorder='big')
type_sep = self.protocols.protocol2num("SEP").to_bytes(length=1,
byteorder='big')
type_msg = self.protocols.sep_type2num("REQ_INIT").to_bytes(
length=1, byteorder='big')
sender_id = self.fix_length(self.OWN_ADDR.encode('utf-8'), 4)
recipient_id = self.fix_length(self.DST_ADDR.encode('utf-8'), 4)
#content
nonce = self.generate_nonce()
#pubkey_a = self.client_pubkey
pubkey_a = self.client_pubkey.export_key()
#with open("public_keys/"+self.OWN_ADDR+".pem", "rb") as f: pubkey_a = f.read()
ctext = b""
ctext += len(pubkey_a).to_bytes(length=4, byteorder='big')
ctext += pubkey_a
nonce_encrypted = self.SEP_ENC(nonce, self.server_pubkey)
ctext += nonce_encrypted
#send msg
msg = self.SEP_GEN(ver, type_sep, type_msg, sender_id, recipient_id,
ctext, self.client_prikey)
self.netif.send_msg(self.DST_ADDR, msg)
#print("Generated nonce: ")
#print(nonce)
#print("encrypted nonce: ")
#print(nonce_encrypted)
return nonce
def SEP_REQ_LOGIN(self):
password = getpass('Type your login password: '******'big')
type_sep = self.protocols.protocol2num("SEP").to_bytes(length=1,
byteorder='big')
type_msg = self.protocols.sep_type2num("REQ_LOGIN").to_bytes(
length=1, byteorder='big')
sender_id = self.fix_length(self.OWN_ADDR.encode('utf-8'), 4)
recipient_id = self.fix_length(self.DST_ADDR.encode('utf-8'), 4)
#keys to be used
#server_public_key = RSA.import_key(open("public_keys/"+self.DST_ADDR+".pem").read())
#client_private_key = RSA.import_key(open("private_keys/"+self.OWN_ADDR+".pem").read())
#content
ctext = self.SEP_ENC(password.encode('utf-8'), self.server_pubkey)
#send msg
msg = self.SEP_GEN(ver, type_sep, type_msg, sender_id, recipient_id,
ctext, self.client_prikey)
self.netif.send_msg(self.DST_ADDR, msg)
return True
def read_SEP(self, msg):
type_msg = msg[2]
if type_msg == self.protocols.sep_type2num(
self.expected_incoming_msg_type):
print("(OK): message type matches")
else:
print("Error: unexpected message type")
return None
msg_len = int.from_bytes(msg[3:8], 'big') #int
if len(msg) == 16 + msg_len + 256:
print("(OK): message length matches")
else:
print("Error: message length does not match")
return None
sender_id = msg[8:12].decode('utf-8').strip(chr(0)) #string
recipient_id = msg[12:16].decode('utf-8').strip(chr(0)) #string
if recipient_id == self.OWN_ADDR:
print("(OK): correct recipient address")
else:
print("Error: wrong recipient address")
return None
# verify signature
sig = msg[-256:]
h = SHA256.new(msg[:-256])
try:
pkcs1_15.new(self.server_pubkey).verify(h, sig)
print("(OK): signature valid")
except:
print("Error: signature invalid")
return None
if type_msg == self.protocols.sep_type2num('RES_INIT'):
#client_private_key = RSA.import_key(open("private_keys/"+self.OWN_ADDR+".pem").read())
#server_public_key = RSA.import_key(open("public_keys/"+self.DST_ADDR+".pem").read())
encrypted_nonce = msg[16:-256]
# decrypt nonce
cipher_rsa = PKCS1_OAEP.new(self.client_prikey)
decrypted_nonce = cipher_rsa.decrypt(encrypted_nonce)
return decrypted_nonce
elif type_msg == self.protocols.sep_type2num('RES_LOGIN'):
encrypted_msg_content = msg[16:-256]
# decrypt
cipher_rsa = PKCS1_OAEP.new(self.client_prikey)
decrypted_msg_content = cipher_rsa.decrypt(encrypted_msg_content)
login_status = decrypted_msg_content[0]
if login_status == 0:
print("Error: login failed due to incorrect password")
return None
elif login_status == 1: # login sucess
session_key = decrypted_msg_content[1:]
print("(OK): password correct")
return session_key
else:
print("Error: uknown response type")
else:
print("Error: unknown message type")
return None
def read_msg(self, msg):
ver = msg[0]
type_protocol = msg[1]
if type_protocol != self.protocols.protocol2num(self.current_protocol):
print(
"Error: unexpected protocol type - received message protocol="
+ type_protocol)
return None, None, None
if type_protocol == self.protocols.protocol2num("SEP"):
return ver, type_protocol, self.read_SEP(msg)
elif type_protocol == self.protocols.protocol2num("FMP"):
return ver, type_protocol, self.read_FMP(msg)
def connect(self):
self.DST_ADDR = input('Type the server address: ')
self.load_client_prikey()
self.load_client_pubkey()
self.load_server_pubkey()
# send SEP REQ_INIT
nonce = None
while True:
nonce = self.SEP_REQ_INIT()
if nonce is not None:
print("SEP REQ INIT sent")
break
# wait for SEP RES_INIT
self.expected_incoming_msg_type = "RES_INIT"
stime = time.time()
while True:
status, msg = self.netif.receive_msg(blocking=False)
if status:
print("SEP RES_INIT received")
ver, type_protocol, nonce_returned = self.read_msg(msg)
if nonce == nonce_returned:
print("(OK): server verified")
print("SEP RES_INIT accpeted")
break
else:
print("Error: server verification failed")
return None
#check request timeout
etime = time.time()
if (etime - stime > self.timeout): # 20 sec timeout
print("Connection request timed out:", self.timeout, "sec")
return None
time.sleep(self.sleep_time)
while True:
# send SEP REQ_LOGIN
while True:
res = self.SEP_REQ_LOGIN()
if res:
break
# wait for SEP RES_LOGIN
self.expected_incoming_msg_type = "RES_LOGIN"
stime = time.time()
while True:
status, msg = self.netif.receive_msg(blocking=False)
if status:
print("SEP RES_LOGIN received")
ver, type_protocol, session_key = self.read_msg(msg)
if session_key is not None:
return session_key
else:
break
etime = time.time()
if (etime - stime > self.timeout):
print("Connection request timed out:", self.timeout, "sec")
return None
time.sleep(self.sleep_time)
def gen_iv(self):
return secrets.token_bytes(16)
def FMP_ENC(self, ptext):
iv = self.gen_iv()
len(self.session_key)
cipher = AES.new(self.session_key, AES.MODE_CBC, iv=iv)
ctext = cipher.encrypt(pad(ptext, AES.block_size))
return iv, ctext
def FMP_MAC(self, msg):
h = HMAC.new(self.session_key, digestmod=SHA256)
h.update(msg)
return h.digest()
def FMP_DEC(self, iv, ctext):
cipher = AES.new(self.session_key, AES.MODE_CBC, iv=iv)
ptext = unpad(cipher.decrypt(ctext), AES.block_size)
return ptext
def FMP_GEN(self, type_msg, content):
ver = self.ver.to_bytes(length=1, byteorder='big')
type_fmp = self.protocols.protocol2num("FMP").to_bytes(length=1,
byteorder='big')
type_msg = self.protocols.fmp_type2num(type_msg).to_bytes(
length=1, byteorder='big')
sender_id = self.fix_length(self.OWN_ADDR.encode('utf-8'), 4)
recipient_id = self.fix_length(self.DST_ADDR.encode('utf-8'), 4)
iv, encrypted_content = self.FMP_ENC(content)
msg = b""
msg += ver
msg += type_fmp
msg += type_msg
msg += (len(iv) + len(encrypted_content)).to_bytes(length=5,
byteorder=('big'))
msg += sender_id
msg += recipient_id
msg += iv
msg += encrypted_content
mac = self.FMP_MAC(msg)
msg += mac
return msg
def FMP_LISTEN(self, command):
# wait for FMP RES
self.expected_incoming_msg_type = command
stime = time.time()
while True:
status, msg = self.netif.receive_msg(blocking=False)
if status:
print("FMP_" + command, "response received")
ver, type_protocol, content = self.read_msg(msg)
if content is not None:
return content
else:
print("Error: response message invalid")
continue
etime = time.time()
if (etime - stime > self.timeout):
print("Error: no response received")
return None
time.sleep(self.sleep_time)
return None
def FMP_SEND(self, msg):
self.netif.send_msg(self.DST_ADDR, msg)
self.seq_last_sent += 1
def FMP_MKD(self):
dir_name = input("Type directory name: ")
# content
# 2 bytes for seq num
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += dir_name.encode('utf-8')
msg = self.FMP_GEN("MKD", content)
self.FMP_SEND(msg)
print("FMP_MKD request sent")
res = self.FMP_LISTEN("MKD")
res = int.from_bytes(res, 'big')
if res == 0:
print("Error: MKD failed")
elif res == 1:
print("MKD: directory created")
def FMP_RMD(self):
dir_name = input("Type directory name: ")
confirm = input("All sub contents will be deleted: (y/n) ")
if confirm != "y":
print("RMD cancelled")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += dir_name.encode('utf-8')
msg = self.FMP_GEN("RMD", content)
self.FMP_SEND(msg)
print("FMP_RMD request sent")
res = self.FMP_LISTEN("RMD")
res = int.from_bytes(res, 'big')
if res == 0:
print("Error: RMD failed")
elif res == 1:
print("RMD: directory deleted")
def FMP_GWD(self):
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
msg = self.FMP_GEN("GWD", content)
self.FMP_SEND(msg)
print("FMP_GWD request sent")
res = self.FMP_LISTEN("GWD")
if res is not None:
res = res.decode('utf-8')
print(res)
def FMP_CWD(self):
dir_name = input("Type destination: ")
# content
# 2 bytes for seq num
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += dir_name.encode('utf-8')
msg = self.FMP_GEN("CWD", content)
self.FMP_SEND(msg)
print("FMP_CWD request sent")
res = self.FMP_LISTEN("CWD")
res = int.from_bytes(res, 'big')
if res == 0:
print("Error: CWD failed")
elif res == 1:
print("CWD: current directory changed")
def FMP_LST(self):
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
msg = self.FMP_GEN("LST", content)
self.FMP_SEND(msg)
print("FMP_LST request sent")
res = self.FMP_LISTEN("LST")
if res is not None:
res = res.decode('utf-8')
res = list(res.split(","))
for i in res:
print(i)
def FMP_UPL(self):
file_name = input("Type file name:")
try:
f_cont = open(
os.path.join(self.FOLDER_PATH, self.DATA_LOC, file_name),
"rb").read()
except:
print("Error: failed to read the file")
return
# content
# 2 bytes for seq num
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += len(file_name).to_bytes(2, ('big'))
content += file_name.encode('utf-8')
content += f_cont
msg = self.FMP_GEN("UPL", content)
self.FMP_SEND(msg)
print("FMP_UPL request sent")
res = self.FMP_LISTEN("UPL")
res = int.from_bytes(res, 'big')
if res == 0:
print("Error: UPL failed")
elif res == 1:
print("UPL: file uploaded")
def FMP_DNL(self):
file_name = input("Type file name: ")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += file_name.encode('utf-8')
msg = self.FMP_GEN("DNL", content)
self.FMP_SEND(msg)
print("FMP_DNL request sent")
res = self.FMP_LISTEN("DNL")
fcont = res[1:].decode('utf-8')
res = res[0]
if res == 0:
print("Error: DNL failed")
elif res == 1:
open(os.path.join(self.FOLDER_PATH, self.DATA_LOC, file_name),
"w").write(fcont)
print("DNL: file downloaded")
def FMP_RMF(self):
file_name = input("Type file name: ")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += file_name.encode('utf-8')
msg = self.FMP_GEN("RMF", content)
self.FMP_SEND(msg)
print("FMP_RMF request sent")
res = self.FMP_LISTEN("RMF")
res = int.from_bytes(res, 'big')
if res == 0:
print("Error: RMF failed")
elif res == 1:
print("RMF: file removed")
def FMP_END(self):
confirm = input("Disconnect and terminate session: (y/n)")
if confirm != 'y':
print("END cancelled")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
msg = self.FMP_GEN("END", content)
self.FMP_SEND(msg)
print("FMP_END request sent")
res = self.FMP_LISTEN("END")
res = int.from_bytes(res, 'big')
if res == 0:
print("Error: END failed")
elif res == 1:
os.sys.exit(0)
print("END: session terminated")
def read_FMP(self, msg):
type_command = msg[2]
msg_len = int.from_bytes(msg[3:8], 'big') #int
if len(msg) == 16 + msg_len + 32:
print("(OK): message length matches")
else:
print("Error: message length does not match")
return None
sender_id = msg[8:12].decode('utf-8').strip(chr(0)) #string
if sender_id == self.DST_ADDR:
print("(OK): correct sender address")
else:
print("Error: wrong sender address")
recipient_id = msg[12:16].decode('utf-8').strip(chr(0)) #string
if recipient_id == self.OWN_ADDR:
print("(OK): correct recipient address")
else:
print("Error: wrong recipient address")
return None
iv = msg[16:32]
ctext = msg[32:-32]
mac = msg[-32:]
# verify mac
h = HMAC.new(self.session_key, digestmod=SHA256)
h.update(msg[:-32])
try:
h.verify(mac)
print("(OK): MAC ok")
except ValueError:
print("Error: MAC verification failed")
return None
# decrypt
ptext = self.FMP_DEC(iv, ctext)
seq_num = int.from_bytes(ptext[0:2], byteorder='big')
content = ptext[2:]
# check seq_num
if seq_num <= self.seq_last_received:
print("Error: invalid sequence number")
return None
else:
self.seq_last_received = seq_num
print("(OK): sequence number ok")
return content
def fmp_process(self):
command = input("Type command: ")
if command == "MKD":
self.FMP_MKD()
elif command == "RMD":
self.FMP_RMD()
elif command == "GWD":
self.FMP_GWD()
elif command == "CWD":
self.FMP_CWD()
elif command == "LST":
self.FMP_LST()
elif command == "UPL":
self.FMP_UPL()
elif command == "DNL":
self.FMP_DNL()
elif command == "RMF":
self.FMP_RMF()
elif command == "END":
self.FMP_END()
else:
print("Error: unknown command")
def start(self):
session_key = None
while True:
session_key = self.connect()
if session_key is not None:
break
print("Connection established with", self.DST_ADDR)
#print(session_key)
self.current_protocol = "FMP"
self.session_key = session_key
self.seq_last_sent = 0
while True:
self.fmp_process()
class Server():
def __init__(self):
self.ver = 1
self.current_protocol = 'SEP' # changed to FMP later
self.expected_incoming_msg_type = "REQ_INIT"
self.OWN_ADDR = "Z" #input("Type your own address: ")
print("Starting server as Z...")
self.DST_ADDR = None
self.NET_PATH = "./network"
self.FOLDER_PATH = "./server"
if (self.NET_PATH[-1] != '/') and (self.NET_PATH[-1] != '\\'):
self.NET_PATH += '/'
if (self.FOLDER_PATH[-1] != '/') and (self.FOLDER_PATH[-1] != '\\'):
self.FOLDER_PATH += '/'
self.netif = network_interface(self.NET_PATH, self.OWN_ADDR)
self.protocols = Protocols()
self.timeout = 30
self.sleep_time = 0.1
self.session_key = None
self.client_pubkey = None
self.client_pubkey_len = None
self.server_prikey = None
# to decrypted saved password and prikey
self.passphrase = "sepfmp"
self.iv = b'\x8c\xbcW\xcf\x0b\xa6\x00\xec\xa7\x94\xd2\x9a\x01Z\xd7\xfc'
#fmp seq num
self.seq_last_received = 0
self.seq_last_sent = 0
#fmp file manipulation
self.client_root_path = None
self.cur_dir = None
def load_server_prikey(self):
try:
key = open(
self.FOLDER_PATH + "private_keys/" + self.OWN_ADDR + ".pem",
"rb").read()
self.server_prikey = RSA.import_key(key,
passphrase=self.passphrase)
except:
print("Error: could not load server private key")
def fix_length(self, input_byte, desired_length):
if (len(input_byte) > desired_length):
print("Error fixing the length of byte")
return
res = b""
for i in range(desired_length - len(input_byte)):
res += b"\x00"
res += input_byte
return res
def generate_session_key(self):
return secrets.token_bytes(32)
def mkpad(self, s, size):
s = s.encode("utf-8") # UTF-8文字列をバイト列に変換する
pad = b' ' * (size - len(s) % size) # 特定の長さの倍数にするための空白を生成
return s + pad
def verify_password(self, password):
key = self.mkpad(self.passphrase, 16)
cipher = AES.new(key, AES.MODE_CBC, self.iv)
ctext = open(self.FOLDER_PATH + "password/" + self.DST_ADDR,
"rb").read()
correct_pwd = cipher.decrypt(ctext)
correct_pwd = correct_pwd.strip(b" ")
if correct_pwd == password:
return True
return False
def gen_iv(self):
return secrets.token_bytes(16)
def SEP_ENC(self, ptext, key):
cipher_rsa = PKCS1_OAEP.new(key)
ctext = cipher_rsa.encrypt(ptext)
return ctext
def SEP_DEC(self, ctext, key):
cipher_rsa = PKCS1_OAEP.new(key)
ptext = cipher_rsa.decrypt(ctext)
return ptext
def SEP_SIGN(self, message, key):
h = SHA256.new(message)
signature = pkcs1_15.new(key).sign(h)
return signature
def SEP_GEN(self, ver, type_sep, type_msg, sender_id, recipient_id,
encrypted_content, sig_key):
msg = b""
msg += ver
msg += type_sep
msg += type_msg
msg += len(encrypted_content).to_bytes(length=5,
byteorder='big') #msg_len
msg += sender_id
msg += recipient_id
msg += encrypted_content
sig = self.SEP_SIGN(msg, sig_key)
#print("Generated sig: ")
#print(sig)
msg += sig
return msg
def SEP_RES_INIT(self, nonce):
#header
ver = self.ver.to_bytes(length=1, byteorder='big')
type_sep = self.protocols.protocol2num("SEP").to_bytes(length=1,
byteorder='big')
type_msg = self.protocols.sep_type2num("RES_INIT").to_bytes(
length=1, byteorder='big')
sender_id = self.fix_length(self.OWN_ADDR.encode('utf-8'), 4)
recipient_id = self.fix_length(self.DST_ADDR.encode('utf-8'), 4)
#content - encrypted nonce
ctext = self.SEP_ENC(nonce, self.client_pubkey)
#send msg
msg = self.SEP_GEN(ver, type_sep, type_msg, sender_id, recipient_id,
ctext, self.server_prikey)
self.netif.send_msg(self.DST_ADDR, msg)
def SEP_RES_LOGIN(self, status, session_key=None):
#header
ver = self.ver.to_bytes(length=1, byteorder='big')
type_sep = self.protocols.protocol2num("SEP").to_bytes(length=1,
byteorder='big')
type_msg = self.protocols.sep_type2num("RES_LOGIN").to_bytes(
length=1, byteorder='big')
sender_id = self.fix_length(self.OWN_ADDR.encode('utf-8'), 4)
recipient_id = self.fix_length(self.DST_ADDR.encode('utf-8'), 4)
login_status = None
ctext = None
if status:
s = 1
login_status = s.to_bytes(length=1, byteorder='big')
ptext = login_status + session_key
ctext = self.SEP_ENC(ptext, self.client_pubkey)
else:
s = 0
login_status = s.to_bytes(length=1, byteorder='big')
ctext = self.SEP_ENC(login_status, self.client_pubkey)
msg = self.SEP_GEN(ver, type_sep, type_msg, sender_id, recipient_id,
ctext, self.server_prikey)
self.netif.send_msg(self.DST_ADDR, msg)
def read_SEP(self, msg):
type_msg = msg[2]
if type_msg == self.protocols.sep_type2num(
self.expected_incoming_msg_type):
print("(OK): protocol type matches")
else:
print("Error: unexpected message type")
return None
msg_len = int.from_bytes(msg[3:8], 'big') #int
if len(msg) == 16 + msg_len + 256:
print("(OK): message length matches")
else:
print("Error: message length does not match")
return None
sender_id = msg[8:12].decode('utf-8').strip(chr(0)) #string
if sender_id == self.DST_ADDR:
print("(OK): correct sender address")
else:
print("Error: wrong sender address")
recipient_id = msg[12:16].decode('utf-8').strip(chr(0)) #string
if recipient_id == self.OWN_ADDR:
print("(OK): correct recipient address")
else:
print("Error: wrong recipient address")
return None
if self.client_pubkey is None and type_msg == self.protocols.sep_type2num(
'REQ_INIT'):
self.client_pubkey_len = int.from_bytes(msg[16:20], 'big')
self.client_pubkey = RSA.import_key(msg[20:20 +
self.client_pubkey_len])
#verify signature
sig = msg[-256:]
h = SHA256.new(msg[:-256])
try:
pkcs1_15.new(self.client_pubkey).verify(h, sig)
print("(OK): sginature valid")
except:
print("Error: signature invalid")
return
if type_msg == self.protocols.sep_type2num('REQ_INIT'):
encrypted_nonce = msg[20 + self.client_pubkey_len:-256]
#decrypt nonce
cipher_rsa = PKCS1_OAEP.new(self.server_prikey)
decrypted_nonce = cipher_rsa.decrypt(encrypted_nonce)
#update internal parameters
self.DST_ADDR = sender_id
return decrypted_nonce
elif type_msg == self.protocols.sep_type2num('REQ_LOGIN'):
encrypted_password = msg[16:-256]
#decrypt password
cipher_rsa = PKCS1_OAEP.new(self.server_prikey)
decrypted_password = cipher_rsa.decrypt(encrypted_password)
return decrypted_password
else:
print("Error: unknown message type")
return None
def FMP_ENC(self, ptext):
iv = self.gen_iv()
len(self.session_key)
cipher = AES.new(self.session_key, AES.MODE_CBC, iv=iv)
ctext = cipher.encrypt(pad(ptext, AES.block_size))
return iv, ctext
def FMP_DEC(self, iv, ctext):
cipher = AES.new(self.session_key, AES.MODE_CBC, iv=iv)
ptext = unpad(cipher.decrypt(ctext), AES.block_size)
return ptext
def FMP_MAC(self, msg):
h = HMAC.new(self.session_key, digestmod=SHA256)
h.update(msg)
return h.digest()
def FMP_GEN(self, type_msg, content):
ver = self.ver.to_bytes(length=1, byteorder='big')
type_fmp = self.protocols.protocol2num("FMP").to_bytes(length=1,
byteorder='big')
type_msg = self.protocols.fmp_type2num(type_msg).to_bytes(
length=1, byteorder='big')
sender_id = self.fix_length(self.OWN_ADDR.encode('utf-8'), 4)
recipient_id = self.fix_length(self.DST_ADDR.encode('utf-8'), 4)
iv, encrypted_content = self.FMP_ENC(content)
msg = b""
msg += ver
msg += type_fmp
msg += type_msg
msg += (len(iv) + len(encrypted_content)).to_bytes(length=5,
byteorder=('big'))
msg += sender_id
msg += recipient_id
msg += iv
msg += encrypted_content
mac = self.FMP_MAC(msg)
msg += mac
return msg
def FMP_SEND(self, msg):
self.netif.send_msg(self.DST_ADDR, msg)
self.seq_last_sent += 1
def FMP_MKD(self, content):
dirname = content.decode('utf-8')
dirnamealnum = dirname.replace("_", "")
dirnamealnum = dirnamealnum.replace("-", "")
if not dirnamealnum.isalnum():
print("Error: invalid directory name")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("MKD", content)
self.FMP_SEND(msg)
print("FMP_MKD response sent")
return
try:
os.makedirs(os.path.join(self.client_root_path, self.cur_dir,
dirname),
exist_ok=True)
except:
print("Error: could not make a new directory")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("MKD", content)
self.FMP_SEND(msg)
print("FMP_MKD response sent")
return
content = None
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("MKD", content)
self.FMP_SEND(msg)
print("MKD: directory created")
print("FMP_MKD response sent")
return
def FMP_RMD(self, content):
dirname = content.decode('utf-8')
dirnamealnum = dirname.replace("_", "")
dirnamealnum = dirnamealnum.replace("-", "")
if not dirnamealnum.isalnum():
print("Error: invalid directory name")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("RMD", content)
self.FMP_SEND(msg)
print("FMP_RMD response sent")
return
try:
shutil.rmtree(
os.path.join(self.client_root_path, self.cur_dir, dirname))
except:
print("Error: could not delete directory")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("RMD", content)
self.FMP_SEND(msg)
print("FMP_RMD response sent")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("RMD", content)
self.FMP_SEND(msg)
print("RMD: directory deleted")
print("FMP_RMD response sent")
return
def FMP_GWD(self, content):
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
if len(self.cur_dir) > 0 and self.cur_dir[0] == ".":
self.cur_dir = self.cur_dir[2:]
cwd = self.DST_ADDR + ":\\" + self.cur_dir
content += cwd.encode('utf-8')
msg = self.FMP_GEN("GWD", content)
self.FMP_SEND(msg)
print("FMP_GWD response sent")
def FMP_CWD(self, content):
dirname = content.decode('utf-8')
dirnamealnum = dirname.replace("_", "")
dirnamealnum = dirnamealnum.replace("-", "")
if dirname == ".." and os.path.normpath(
self.cur_dir) != os.path.normpath(""):
pass
elif not dirnamealnum.isalnum():
print("Error: invalid destinatino directory")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("CWD", content)
self.FMP_SEND(msg)
print("FMP_CWD response sent")
return
elif not os.access(
os.path.join(self.client_root_path, self.cur_dir, dirname),
os.F_OK):
print("Error: the destination path does not exist")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("CWD", content)
self.FMP_SEND(msg)
print("FMP_CWD response sent")
return
try:
if dirname == "..":
self.cur_dir = str(Path(self.cur_dir).parent)
else:
self.cur_dir = os.path.join(self.cur_dir, dirname)
except:
print("Error: could not change directory")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("CWD", content)
self.FMP_SEND(msg)
print("FMP_CWD response sent")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("CWD", content)
self.FMP_SEND(msg)
print("CWD: current directory changed")
print("FMP_CWD response sent")
return
def FMP_LST(self, content):
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
dirlist = os.listdir(os.path.join(self.client_root_path, self.cur_dir))
dirlist_text = ""
for item in dirlist:
dirlist_text += item + ","
content += dirlist_text.encode('utf-8')
msg = self.FMP_GEN("LST", content)
self.FMP_SEND(msg)
print("FMP_LST response sent")
def FMP_UPL(self, content):
fname_len = int.from_bytes(content[:2], 'big')
decoded_content = content[2:].decode('utf-8')
fname = decoded_content[:fname_len]
fcont = decoded_content[fname_len:]
fnamealnum = fname.replace("_", "")
fnamealnum = fnamealnum.replace("-", "")
fnamealnum = fnamealnum.replace(".", "")
if not fnamealnum.isalnum():
print("Error: invalid file name")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("UPL", content)
self.FMP_SEND(msg)
print("FMP_UPL response sent")
return
try:
fname = os.path.join(self.client_root_path, self.cur_dir, fname)
with open(fname, "w") as f:
f.write(fcont)
except:
print("Error: could not make a file")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("UPL", content)
self.FMP_SEND(msg)
print("FMP_UPL response sent")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("UPL", content)
self.FMP_SEND(msg)
print("UPL: file uploaded")
print("FMP_UPL response sent")
return
def FMP_DNL(self, content):
fname = content.decode('utf-8')
try:
f_cont = open(
os.path.join(self.client_root_path, self.cur_dir, fname),
"rb").read()
except:
print("Error: could not read the file")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("UPL", content)
self.FMP_SEND(msg)
print("FMP_DNL response sent")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
content += f_cont
msg = self.FMP_GEN("DNL", content)
self.FMP_SEND(msg)
print("DNL: directory created")
print("FMP_DNL response sent")
return
def FMP_RMF(self, content):
fname = content.decode('utf-8')
dirnamealnum = fname.replace("_", "")
dirnamealnum = dirnamealnum.replace("-", "")
dirnamealnum = dirnamealnum.replace(".", "")
if not dirnamealnum.isalnum():
print("Error: invalid directory name")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("RMF", content)
self.FMP_SEND(msg)
print("FMP_RMD response sent")
return
try:
os.remove(os.path.join(self.client_root_path, self.cur_dir, fname))
except:
print("Error: could not remove the file")
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (0).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("RMF", content)
self.FMP_SEND(msg)
print("FMP_RMF response sent")
return
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("RMF", content)
self.FMP_SEND(msg)
print("RMF: directory created")
print("FMP_RMF response sent")
return
def FMP_END(self, content):
content = (self.seq_last_sent + 1).to_bytes(2, 'big')
content += (1).to_bytes(length=1, byteorder='big')
msg = self.FMP_GEN("END", content)
self.FMP_SEND(msg)
print("FMP_END response sent")
print("END: session terminated")
os.sys.exit(0)
return
def read_FMP(self, msg):
type_command = msg[2]
msg_len = int.from_bytes(msg[3:8], 'big') #int
if len(msg) == 16 + msg_len + 32:
print("(OK): message length matches")
else:
print("Error: message length does not match")
return None
sender_id = msg[8:12].decode('utf-8').strip(chr(0)) #string
if sender_id == self.DST_ADDR:
print("(OK): correct sender address")
else:
print("Error: wrong sender address")
recipient_id = msg[12:16].decode('utf-8').strip(chr(0)) #string
if recipient_id == self.OWN_ADDR:
print("(OK): correct recipient address")
else:
print("Error: wrong recipient address")
return None
iv = msg[16:32]
ctext = msg[32:-32]
mac = msg[-32:]
# verify mac
h = HMAC.new(self.session_key, digestmod=SHA256)
h.update(msg[:-32])
try:
h.verify(mac)
print("(OK): MAC ok")
except ValueError:
print("Error: MAC verification failed")
return None
# decrypt
ptext = self.FMP_DEC(iv, ctext)
seq_num = int.from_bytes(ptext[0:2], byteorder='big')
content = ptext[2:]
# check seq_num
if seq_num <= self.seq_last_received:
print("Error: invalid sequence number")
return None
else:
self.seq_last_received = seq_num
print("(OK): sequence number ok")
if type_command == self.protocols.fmp_type2num("MKD"):
self.FMP_MKD(content)
elif type_command == self.protocols.fmp_type2num("RMD"):
self.FMP_RMD(content)
elif type_command == self.protocols.fmp_type2num("GWD"):
self.FMP_GWD(content)
elif type_command == self.protocols.fmp_type2num("CWD"):
self.FMP_CWD(content)
elif type_command == self.protocols.fmp_type2num("LST"):
self.FMP_LST(content)
elif type_command == self.protocols.fmp_type2num("UPL"):
self.FMP_UPL(content)
elif type_command == self.protocols.fmp_type2num("DNL"):
self.FMP_DNL(content)
elif type_command == self.protocols.fmp_type2num("RMF"):
self.FMP_RMF(content)
elif type_command == self.protocols.fmp_type2num("END"):
self.FMP_END(content)
else:
print("Error: unknown type_command")
def read_msg(self, msg):
ver = msg[0]
type_protocol = msg[1]
if type_protocol != self.protocols.protocol2num(self.current_protocol):
print(
"Error: unexpected protocol type - received message protocol="
+ type_protocol)
return None, None, None
if type_protocol == self.protocols.protocol2num("SEP"):
return ver, type_protocol, self.read_SEP(msg)
elif type_protocol == self.protocols.protocol2num("FMP"):
return ver, type_protocol, self.read_FMP(msg)
#Todo: create self.read_FMP
else:
print("Error: unexpected protocol")
def connect(self):
self.current_protocol = "SEP"
self.expected_incoming_msg_type = "REQ_INIT"
status = None
msg = None
# wait for SEP REQ_INIT
self.expected_incoming_msg_type = "REQ_INIT"
while True:
status, msg = self.netif.receive_msg(blocking=True)
print("SEP REQ_INIT received")
ver, type_protocol, decrypted_nonce = self.read_msg(msg)
if decrypted_nonce is not None:
print("SEP REQ_INIT accepted")
self.SEP_RES_INIT(decrypted_nonce)
print("SEP RES_INIT sent")
break
else:
print("Error: SEP REQ_INIT rejected")
return None
# wait for SEP REQ_LOGIN
self.expected_incoming_msg_type = "REQ_LOGIN"
stime = time.time()
while True:
status, msg = self.netif.receive_msg(blocking=False)
if status:
print("SEP REQ_LOGIN received")
ver, type_protocol, password = self.read_msg(msg)
if password is not None:
print("SEP REQ_LOGIN accepted")
# TODO SEP RES LOGIN
if self.verify_password(password):
print("(OK): password ok")
session_key = self.generate_session_key()
self.SEP_RES_LOGIN(True, session_key=session_key)
print("SEP RES_LOGIN sent")
return session_key
else:
print("(!!): password incorrect")
self.SEP_RES_LOGIN(False)
print("SEP RES_LOGIN sent")
continue # keep waiting for correct password
#cehck request timeout
etime = time.time()
if (etime - stime > self.timeout):
print("Connection request timed out:", self.timeout, "sec")
return None
time.sleep(self.sleep_time)
def start(self):
self.load_server_prikey()
session_key = None
while True:
session_key = self.connect()
if session_key is not None:
break
print("Connection established with", self.DST_ADDR)
#print(session_key)
self.current_protocol = "FMP"
self.client_root_path = os.path.join(self.FOLDER_PATH, "client_data",
self.DST_ADDR)
self.cur_dir = ""
self.session_key = session_key
while True:
status, msg = self.netif.receive_msg(blocking=True)
print("FMP REQ received")
self.read_msg(msg)