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Implement basic replay protection #173

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Merged
merged 2 commits into from
Jan 9, 2023
Merged

Implement basic replay protection #173

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a5e7ae8
Implement basic replay protection
Sandwichs-del Jan 9, 2023
cd7eee9
fix typo
Sandwichs-del Jan 9, 2023
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9 changes: 8 additions & 1 deletion pysyncobj/tcp_connection.py
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@ def __init__(self, poller, onMessageReceived = None, onConnected = None, onDisco

self.sendRandKey = None
self.recvRandKey = None
self.recvLastTimestamp = 0
self.encryptor = None

self.__socket = socket
Expand Down Expand Up @@ -101,7 +102,7 @@ def send(self, message):
message = (self.sendRandKey, message)
data = zlib.compress(pickle.dumps(message), 3)
if self.encryptor:
data = self.encryptor.encrypt(data)
data = self.encryptor.encrypt_at_time(data, int(monotonicTime()))
data = struct.pack('i', len(data)) + data
self.__writeBuffer += data
self.__trySendBuffer()
Expand All @@ -115,6 +116,7 @@ def disconnect(self):
needCallDisconnect = True
self.sendRandKey = None
self.recvRandKey = None
self.recvLastTimestamp = 0
if self.__socket is not None:
self.__socket.close()
self.__socket = None
Expand Down Expand Up @@ -232,12 +234,17 @@ def __processParseMessage(self):
data = self.__readBuffer[4:4 + l]
try:
if self.encryptor:
dataTimestamp = self.encryptor.extract_timestamp(data)
assert dataTimestamp >= self.recvLastTimestamp
self.recvLastTimestamp = dataTimestamp
# Unfortunately we can't get a timestamp and data in one go
data = self.encryptor.decrypt(data)
message = pickle.loads(zlib.decompress(data))
if self.recvRandKey:
randKey, message = message
assert randKey == self.recvRandKey
except:
# Why no logging of security errors?
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You can add logging

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Ha, of course. I see PySyncObj already has logging imported so printing something like "invalid message received from $ip, closing connection" should be not hard. I'll do a separate PR after I figure exactly how.

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Hm, do you think it should be logger.warning or more like logger.info? On private network it feels like warning because it means I have broken app somewhere, but on internet it feels wrong because I receive lot of junk, so its more like info or debug. Er, is it good idea to write anything to log just because somebody from internet connected?

wow... you are fast! Thank you.

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Probably that's the reason it was missing in log ) Probably we can leave it as is for now..

self.disconnect()
return None
self.__readBuffer = self.__readBuffer[4 + l:]
Expand Down