or-ctl-filter - "control-port-filter" without the bash.

Yawning Angel (yawning at schwanenlied dot me)

or-ctl-filter is a Tor Control Port filter/shim. It used to be a bash-less rewrite of "control-port-filter" by the Whonix developers, but they have since rewrote "control-port-filter" in Python, and or-ctl-filter has been extended to provide much more functionality.

Dependencies:

• https://github.com/BurntSushi/toml (TOML parser)
• https://github.com/yawning/bulb (Control port library)
• Tor (Runtime, optional)
• I2P (Runtime, optional)

Limitations/differences:

• It only supports NULL and SAFECOOKIE authentication.
• It does not limit request lengths, because that's tor's problem, not mine.
• It does not allow GETINFO inquries regarding tor's bootstrap process.
• It supports any combination of Tor, and I2P, including "neither".

Commands allowed:

• "GETINFO net/listeners/socks"
• "SIGNAL NEWNYM"

Example torrc:

# This requires the control port and cookie auth.
CookieAuthentication 1
CookieAuthFile /var/run/tor/control_auth_cookie
CookieAuthFileGroupReadable 1

ControlSocket /var/run/tor/control
ControlSocketsGroupWritable 1

How to run:

$ or-ctl-filter -config=/path/to/or-ctl-filter.toml &
$ export TOR_SKIP_LAUNCH=1
$ start-tor-browser

I personally call or-ctl-filter from my openbox autostart file. Bad things will happen if multiple instances are ran at the same time, unless different configurations are specified.

Notes:

• Why yes, this assumes that both I2P and Tor are running as system services, and has no logic to launch either.
• It should work on Windows, but it is entirely untested and won't be.
• "New Identity" does not change the I2P path.
• "New Tor Circuit for this Site" does not change the I2P path.
• A few options are gigantic "Foot + Gun" items for the user. In particular, logging is unsanitized and incredibly spammy, and UnsafeAllowDirect can allow for direct connections to the internet.

TODO:

• Add support for I2P and RESOLVE/RESOLVE_PTR, so torsocks will work.
• Add support for authenticating with a password, though that sucks and everyone should use cookie auth.
• Think about I2P outproxy support (But honestly, why when Tor is available).
• Consider allowing the Tor circuit display to work.
• Consider allowing bootstrap related events.

Acknowledgements:

• https://www.whonix.org/wiki/Dev/Control_Port_Filter_Proxy