-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi all,
This is the 5th status report for the GSoC project. These last days I've been struggling with a problem that has been annoying me for already some weeks but I had not tackled until now because I had given to it low priority. The issue is that I observe TCP requests to the Pluggable Transport client coming from the Tor client. Whenever the 'StaticDestinationServerFactory' listener receives a TCP connection, it creates a new instance of the PT client and a new circuit which, at the same time, induces the creation of a new PT server object downstream, at the other end. In the beginning I thought that this was due to some bug that I had introduced myself but, after talking with George Kadianakis, it seems to be the expected behavior of obfsproxy. This might be a major limitation to implement wfpadtools in obfsproxy. In order to inject dummy messages in a consistent way, I need all the traffic to be multiplexed in one single stream. This observation is however in contradiction with the Tor protocol itself because between the Tor client and the bridge/entry guard there is supposed to be a TLS connection. TCP traffic coming from the application being tunneled through Tor is relayed over this TLS connection. So, in theory TCP connections coming from the browser should be already multiplexed at this point (PT client - PT server). Maybe I'm missing something. I cannot find the origin of the problem and it is really blocking me because in my opinion this could be a fundamental flaw of wfpadtools. Before getting into this I also worked in the following: - - Modified wfpadtools protocol to be able to send control messages with arguments that don't fit in the MTU (it spitts them in more than one wfpadtool message): added a new field in the wfpadtools message header and adapted message parser accordingly. - - I also modified the shim observer in wfpad and wrote some tests for it (http://goo.gl/5YCpS5). - - As I said in the last report, for testing purposes I wrote a transport wrapper for wfpad that dumps the state and all received messages into a temp file (http://goo.gl/eAjGs2). To test a primitive, I simulate sending a control message from the PT client (through a special message that only the wrapper can speak) and load the dumps to check that they correspond to the state I would get if running such primitive. Last week I finished writing this wrapper and I already wrote tests for some primitives. For example, for the primitive 'sendPadding(5, 0.1)' I expect to see a control message from client to server and 5 padding messages delayed 0.1ms from the server to the client (http://goo.gl/mlaRop). - - Fixed a bug related to the stop condition at the wfpad base class and wrote some documentation at beginning of the wfpad module. Best, - -- marc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJT3C66AAoJEGfJ5xfgazlxbPUH/jVg1DdKluT3bgPkMUODaEPe eiXQyLLsN2FnIc0atAfmjOTsX2A1rGsWrGXbjEZ2KqkubAbDda6XGhcoFrpF9bkA BetACZ33j1QCtBbQTg5TpbIE5PjlPSmXQvbINx5EJ/9xWqD812eaR/0T3Ov5nAEh div6RCyqNAe+fqkVzC+Hs9mISFHEfOKM6kwt3sOwbgZipcAEQCsuv0hU4qhaR1/Q QGPeDojZG65+7/Rdo5blp2oTh2Q6HOFxc6Pcv1voAPjkTkEF8Cu9E2ilrSxbYN6B 0TvoLAUsRPc4TlPyyumL7xNIpVQHIM7nlWPU/Dee2Jw2cPb2571mn/OzWt3Z0Yg= =j6GE -----END PGP SIGNATURE----- _______________________________________________ tor-reports mailing list [email protected] https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-reports
