commit aeebf8950ad137478b661cc2b6fa4c47c5f88f2f Author: George Kadianakis <desnacked@riseup.net> Date: Thu Dec 6 16:38:44 2012 +0200 Some additions related to the Extended ORPort. --- proposals/180-pluggable-transport.txt | 34 +--------------------------- proposals/196-transport-control-ports.txt | 24 ++++++++++++++++++- pt-spec.txt | 6 +++++ 3 files changed, 30 insertions(+), 34 deletions(-) diff --git a/proposals/180-pluggable-transport.txt b/proposals/180-pluggable-transport.txt index cc279c2..2e63f2e 100644 --- a/proposals/180-pluggable-transport.txt +++ b/proposals/180-pluggable-transport.txt @@ -443,39 +443,9 @@ Managed proxy interface should set the environment variable: TOR_PT_MANAGED_TRANSPORT_VER=1 -The extended ORPort protocol +The Extended ORPort protocol - Server transports may need to connect to the bridge and pass - additional information about client connections that the bridge - would ordinarily receive from the kernel's TCP stack. To do this, - they connect to the "extended server port" as given in - EXTENDED_SERVER_PORT, send a short amount of information, wait for a - response, and then send the user traffic on that port. - - The extended server port protocol is as follows: - - COMMAND [2 bytes, big-endian] - BODYLEN [2 bytes, big-endian] - BODY [BODYLEN bytes] - - Commands sent from the transport to the server are: - - [0x0000] DONE: There is no more information to give. (body ignored) - - [0x0001] USERADDR: an address:port string that represents the user's - address. If the transport doesn't actually do addresses, - this shouldn't be sent. - - Replies sent from tor to the proxy are: - - [0x1001] OKAY: Send the user's traffic. (body ignored) - - [0x1002] DENY: Tor would prefer not to get more traffic from - this address for a while. (body ignored) - - [We could also use an out-of-band signalling method to tell Tor - about client addresses, but that's a historically error-prone way - to go about annotating connections.] + The Extended ORPort protocol is described in proposal 196. Advertising bridge methods diff --git a/proposals/196-transport-control-ports.txt b/proposals/196-transport-control-ports.txt index 549e8ce..c7f1c3a 100644 --- a/proposals/196-transport-control-ports.txt +++ b/proposals/196-transport-control-ports.txt @@ -159,7 +159,27 @@ Target: 0.2.4.x command it MAY want to shutdown its connections to the transport proxy. -5. Security Considerations +5. Authentication + + To defend against cross-protocol attacks on the Extended ORPOrt, + proposal 213 defines an authentication scheme that should be used to + protect it. + + If the Extended ORPort is enabled, Tor should regenerate the cookie + file of proposal 213 on startup and store it in + $DataDirectory/extended_orport_auth_cookie. + + The location of the cookie can be overriden by using the + configuration file parameter ExtORPortCookieAuthFile, which is + defined as: + + ExtORPortCookieAuthFile <path> + + where <path> is a filesystem path. + + XXX should we also add an ExtORPortCookieFileGroupReadable torrc option? + +6. Security Considerations Extended ORPort or TransportControlPort do _not_ provide link confidentiality, authentication or integrity. Sensitive data, like @@ -176,7 +196,7 @@ Target: 0.2.4.x instructed to connect to a non-localhost Extended ORPort or TransportControlPort. -6. Future +7. Future In the future, we might have pluggable transports which require the _client_ transport proxy to use the TransportControlPort and exchange diff --git a/pt-spec.txt b/pt-spec.txt index 0da004a..72662b6 100644 --- a/pt-spec.txt +++ b/pt-spec.txt @@ -212,6 +212,12 @@ Managed proxy interface doesn't recognize. Example: TOR_PT_SERVER_TRANSPORTS=trebuchet,ballista + "TOR_PT_AUTH_COOKIE_FILE" -- A filesystem path where the proxy + should expect to find the authentication cookie to be able to + communicate with the Extended ORPort and TransportControlPort. + TOR_PT_AUTH_COOKIE_FILE is optional and might not be present in + the environment of the proxy. + The transport proxy replies by writing NL-terminated lines to stdout. The line metaformat is