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[tor-talk] Obfsproxy question



Hi,

I am not sure if this is a correct place to ask, but I will risk.... :-)

I am trying to set up OpenVPN server with Obfsproxy. I am using
Obfsproxy 0.2.13 on both sides (server and client).

On server (Debian 9), there is OpenVPN server listening on 443 TCP port.
I am also using port sharing in OpenVPN so if someone connects to my
server to 443 port with OpenVPN, he gets OpenVPN connection, but if
someone connects to my server to 443 port with web browser (HTTPS), it
will get website. (This is possible because OpenVPN can distinguish
OpenVPN and other connections - others are relayed to webserver running
on localhost on some other port.)

Then I run Obfsproxy on the server with the following command:

sudo obfsproxy --log-min-severity=debug
--data-dir=/tmp/scramblesuit-server scramblesuit
--password=ZKRSAUKWPH6A3GMINURTUG2I6GJQR4ZV --dest=127.0.0.1:443 server
0.0.0.0:8080

So basically, server is listening to port 8080 and relaying all
connections to 443 TCP where they are taken over by OpenVPN.


Now the client side (Ubuntu 17.04).

I installed Obfsproxy via pip install and am running this command:

obfsproxy --log-min-severity=debug --data-dir=/tmp/scramblesuit-client
scramblesuit --password=ZKRSAUKWPH6A3GMINURTUG2I6GJQR4ZV --dest
xx.xx.xx.xx:8080 socks 127.0.0.1:10194

So basically, Obfsproxy is connecting to my server to port 8080 and
opening socks on client's localhost on port 10194.

And finally, OpenVPN client config has basically just socks-proxy line
added:

client
remote xx.xx.xx.xx 443
proto tcp
socks-proxy 127.0.0.1 10194
dev tun
...
...


Now the problem is, that when I run OpenVPN client, it can't connect and
the problem is in Obfsproxy client.

Here is the Obfsproxy's log:

################################################
Do NOT rely on ScrambleSuit for strong security!
################################################

2017-09-26 19:54:16,672 [DEBUG] Setting the state location to
`/tmp/scramblesuit-client/scramblesuit/'.
2017-09-26 19:54:16,673 [INFO] OBFSSOCKSv5Factory starting on 10194
2017-09-26 19:54:16,673 [INFO] Starting factory
<obfsproxy.network.socks.OBFSSOCKSv5Factory instance at 0x7fc077f6b2d8>
2017-09-26 19:54:16,673 [DEBUG] socks_fact_0x7fc077f6b2d8: Starting up
SOCKS server factory.
2017-09-26 19:54:16,673 [INFO] Launched 'socks' listener at
'[scrubbed]:10194' for transport 'scramblesuit'.
2017-09-26 19:54:54,126 [DEBUG] socks_fact_0x7fc077f6b2d8: New connection.
2017-09-26 19:54:54,126 [DEBUG] Initialising ScrambleSuit.
2017-09-26 19:54:54,126 [DEBUG] Switching to state ST_WAIT_FOR_AUTH.
2017-09-26 19:54:54,126 [DEBUG] Initialising AES-CTR instance.
2017-09-26 19:54:54,126 [DEBUG] Initialising AES-CTR instance.
2017-09-26 19:54:54,126 [DEBUG] Dumping probability distribution.
2017-09-26 19:54:54,127 [DEBUG] P(271) = 0.623
2017-09-26 19:54:54,127 [DEBUG] P(321) = 0.321
2017-09-26 19:54:54,127 [DEBUG] P(1374) = 0.031
2017-09-26 19:54:54,127 [DEBUG] P(127) = 0.014
2017-09-26 19:54:54,127 [DEBUG] Dumping probability distribution.
2017-09-26 19:54:54,127 [DEBUG] P(0.00310045817413) = 0.012
2017-09-26 19:54:54,127 [DEBUG] P(0.00813930754249) = 0.703
2017-09-26 19:54:54,127 [DEBUG] P(0.00224023279255) = 0.269
2017-09-26 19:54:54,127 [DEBUG] P(0.00564475385899) = 0.011
2017-09-26 19:54:54,161 [DEBUG] circ_0x7fc077f845a8: Setting downstream
connection (socks_down_0x7fc0781d9710).
2017-09-26 19:54:54,161 [DEBUG] circ_0x7fc077f845a8: Setting upstream
connection (socks_up_0x7fc0781eab90).
2017-09-26 19:54:54,161 [DEBUG] circ_0x7fc077f845a8: Circuit completed.
2017-09-26 19:54:54,161 [DEBUG] Attempting to read master key and ticket
from file `/tmp/scramblesuit-client/scramblesuit/session_ticket.yaml'.
2017-09-26 19:54:54,161 [DEBUG] File
`/tmp/scramblesuit-client/scramblesuit/session_ticket.yaml' does not
exist (yet?).
2017-09-26 19:54:54,161 [DEBUG] No session ticket to redeem.  Running
UniformDH.
2017-09-26 19:54:54,162 [DEBUG] Creating UniformDH handshake message.
2017-09-26 19:54:54,176 [DEBUG] circ_0x7fc077f845a8: upstream: Received
88 bytes.
2017-09-26 19:54:54,176 [DEBUG] Buffered 88 bytes of outgoing data.
2017-09-26 19:54:54,185 [DEBUG] socks_down_0x7fc0781d9710: Recived 0 bytes.
2017-09-26 19:54:54,186 [DEBUG] circ_0x7fc077f845a8: downstream:
Received 0 bytes.
2017-09-26 19:54:54,186 [DEBUG] Unable to finish UniformDH handshake
just yet.
2017-09-26 19:54:54,297 [DEBUG] socks_down_0x7fc0781d9710: Recived 652
bytes.
2017-09-26 19:54:54,297 [DEBUG] circ_0x7fc077f845a8: downstream:
Received 652 bytes.
2017-09-26 19:54:54,297 [DEBUG] Attempting to extract the remote
machine's UniformDH public key out of 652 bytes of data.
2017-09-26 19:54:54,297 [DEBUG] Could not find the mark just yet.
2017-09-26 19:54:54,297 [DEBUG] Unable to finish UniformDH handshake
just yet.
2017-09-26 19:54:54,298 [DEBUG] socks_up_0x7fc0781eab90: Connection was
lost (Connection was closed cleanly.).
2017-09-26 19:54:54,298 [DEBUG] socks_up_0x7fc0781eab90: Closing connection.
2017-09-26 19:54:54,299 [DEBUG] circ_0x7fc077f845a8: Tearing down circuit.
2017-09-26 19:54:54,299 [DEBUG] socks_down_0x7fc0781d9710: Closing
connection.


Is this problem somehow connected with warning about session_ticket.yaml?

Directory /tmp/scramblesuit-client/scramblesuit/ on a client exists, but
is empty.

Any help will be much appreciated.

Regards,
M.
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