Commit 7ec9a684 authored by George Kadianakis's avatar George Kadianakis
Browse files

Service intro circuits are now 4-hop to avoid linkability by intro

Now the circuits look like this:

	 client rend:   C -> G -> L2 -> Rend
	 client intro:  C -> G -> L2 -> M -> Intro
	 client hsdir:  C -> G -> L2 -> M -> HSDir
	 service rend:  C -> G -> L2 -> M -> Rend
	 service intro: C -> G -> L2 -> M -> Intro
	 service hsdir: C -> G -> L2 -> M -> HSDir
parent 9b464cdc
......@@ -1394,16 +1394,14 @@ route_len_for_purpose(uint8_t purpose, extend_info_t *exit_ei)
return routelen;
switch (purpose) {
/* These two purposes connect to a router that we chose, so
* DEFAULT_ROUTE_LEN is safe. */
case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
/* hidden service connecting to introduction point */
/* These purposes connect to a router that we chose, so DEFAULT_ROUTE_LEN
* is safe: */
case CIRCUIT_PURPOSE_TESTING:
/* router reachability testing */
known_purpose = 1;
break;
/* These three purposes connect to a router that someone else
/* These purposes connect to a router that someone else
* might have chosen, so add an extra hop to protect anonymity. */
case CIRCUIT_PURPOSE_C_GENERAL:
case CIRCUIT_PURPOSE_C_HSDIR_GET:
......@@ -1413,6 +1411,9 @@ route_len_for_purpose(uint8_t purpose, extend_info_t *exit_ei)
/* client connecting to introduction point */
case CIRCUIT_PURPOSE_S_CONNECT_REND:
/* hidden service connecting to rendezvous point */
case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
/* hidden service connecting to intro point. In this case we want an extra
hop to avoid linkability attacks by the introduction point. */
known_purpose = 1;
routelen++;
break;
......
......@@ -113,7 +113,7 @@ test_new_route_len_safe_exit(void *arg)
/* hidden service connecting to introduction point */
r = new_route_len(CIRCUIT_PURPOSE_S_ESTABLISH_INTRO, &dummy_ei,
&dummy_nodes);
tt_int_op(DEFAULT_ROUTE_LEN, OP_EQ, r);
tt_int_op(DEFAULT_ROUTE_LEN+1, OP_EQ, r);
/* router testing its own reachability */
r = new_route_len(CIRCUIT_PURPOSE_TESTING, &dummy_ei, &dummy_nodes);
......
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