/* Copyright 2004 Roger Dingledine */ /* See LICENSE for licensing information */ /* $Id$ */ #include "or.h" /* send the introduce cell */ void rend_client_introcirc_is_open(circuit_t *circ) { assert(circ->purpose == CIRCUIT_PURPOSE_C_INTRODUCING); assert(CIRCUIT_IS_ORIGIN(circ) && circ->cpath); log_fn(LOG_INFO,"introcirc is open"); connection_ap_attach_pending(); } /* send the establish-rendezvous cell. if it fails, mark * the circ for close and return -1. else return 0. */ int rend_client_send_establish_rendezvous(circuit_t *circ) { assert(circ->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND); log_fn(LOG_INFO, "Sending an ESTABLISH_RENDEZVOUS cell"); if (crypto_rand(REND_COOKIE_LEN, circ->rend_cookie)<0) { log_fn(LOG_WARN, "Couldn't get random cookie"); circuit_mark_for_close(circ); return -1; } if (connection_edge_send_command(NULL,circ, RELAY_COMMAND_ESTABLISH_RENDEZVOUS, circ->rend_cookie, REND_COOKIE_LEN, circ->cpath->prev)<0) { /* circ is already marked for close */ log_fn(LOG_WARN, "Couldn't send ESTABLISH_RENDEZVOUS cell"); return -1; } return 0; } /* Called when we're trying to connect an ap conn; sends an INTRODUCE1 cell * down introcirc if possible. */ int rend_client_send_introduction(circuit_t *introcirc, circuit_t *rendcirc) { int payload_len, r; char payload[RELAY_PAYLOAD_SIZE]; char tmp[(MAX_NICKNAME_LEN+1)+REND_COOKIE_LEN+DH_KEY_LEN]; rend_cache_entry_t *entry; crypt_path_t *cpath; assert(introcirc->purpose == CIRCUIT_PURPOSE_C_INTRODUCING); assert(rendcirc->purpose == CIRCUIT_PURPOSE_C_REND_READY); assert(!rend_cmp_service_ids(introcirc->rend_query, rendcirc->rend_query)); if(rend_cache_lookup_entry(introcirc->rend_query, &entry) < 1) { log_fn(LOG_WARN,"query '%s' didn't have valid rend desc in cache. Failing.", introcirc->rend_query); goto err; } /* first 20 bytes of payload are the hash of bob's pk */ if (crypto_pk_get_digest(entry->parsed->pk, payload)<0) { log_fn(LOG_WARN, "Couldn't hash public key."); goto err; } /* Initialize the pending_final_cpath and start the DH handshake. */ cpath = rendcirc->build_state->pending_final_cpath = tor_malloc_zero(sizeof(crypt_path_t)); if (!(cpath->handshake_state = crypto_dh_new())) { log_fn(LOG_WARN, "Couldn't allocate DH"); goto err; } if (crypto_dh_generate_public(cpath->handshake_state)<0) { log_fn(LOG_WARN, "Couldn't generate g^x"); goto err; } /* write the remaining items into tmp */ strncpy(tmp, rendcirc->build_state->chosen_exit, (MAX_NICKNAME_LEN+1)); /* nul pads */ memcpy(tmp+MAX_NICKNAME_LEN+1, rendcirc->rend_cookie, REND_COOKIE_LEN); if (crypto_dh_get_public(cpath->handshake_state, tmp+MAX_NICKNAME_LEN+1+REND_COOKIE_LEN, DH_KEY_LEN)<0) { log_fn(LOG_WARN, "Couldn't extract g^x"); goto err; } r = crypto_pk_public_hybrid_encrypt(entry->parsed->pk, tmp, MAX_NICKNAME_LEN+1+REND_COOKIE_LEN+DH_KEY_LEN, payload+DIGEST_LEN, PK_PKCS1_OAEP_PADDING, 0); if (r<0) { log_fn(LOG_WARN,"hybrid pk encrypt failed."); goto err; } payload_len = DIGEST_LEN + r; if (connection_edge_send_command(NULL, introcirc, RELAY_COMMAND_INTRODUCE1, payload, payload_len, introcirc->cpath->prev)<0) { /* introcirc is already marked for close. leave rendcirc alone. */ log_fn(LOG_WARN, "Couldn't send INTRODUCE1 cell"); return -1; } /* Now, we wait for an ACK or NAK on this circuit. */ introcirc->purpose = CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT; return 0; err: circuit_mark_for_close(introcirc); circuit_mark_for_close(rendcirc); return -1; } /* send the rendezvous cell */ void rend_client_rendcirc_is_open(circuit_t *circ) { assert(circ->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND); assert(CIRCUIT_IS_ORIGIN(circ)); log_fn(LOG_INFO,"rendcirc is open"); /* generate a rendezvous cookie, store it in circ */ if (rend_client_send_establish_rendezvous(circ) < 0) { return; } connection_ap_attach_pending(); } /* Called when get an ACK or a NAK for a REND_INTRODUCE1 cell. */ int rend_client_introduction_acked(circuit_t *circ, const char *request, int request_len) { if (circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) { log_fn(LOG_WARN, "Recieved REND_INTRODUCE_ACK on unexpected circuit %d", circ->n_circ_id); circuit_mark_for_close(circ); return -1; } if (request_len == 0) { /* It's an ACK; the introduction point relayed our introduction request. */ /* So close the circuit; we won't need it any more. */ circuit_mark_for_close(circ); } else { /* It's a NAK; the introduction point didn't relay our request. */ circ->purpose = CIRCUIT_PURPOSE_C_INTRODUCING; /* XXXX * Now become non-open, extend to another one of Bob's * introduction points, and try again. Maybe mark the service as * non-functional at the first intro point somehow? * * Or re-fetch the service descriptor? Hm.... * * XXXX writeme */ } return 0; } /* Called when we receive a RENDEZVOUS_ESTABLISHED cell; changes the state of * the circuit to C_REND_READY. */ int rend_client_rendezvous_acked(circuit_t *circ, const char *request, int request_len) { /* we just got an ack for our establish-rendezvous. switch purposes. */ if(circ->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND) { log_fn(LOG_WARN,"Got a rendezvous ack when we weren't expecting one. Closing circ."); circuit_mark_for_close(circ); return -1; } log_fn(LOG_INFO,"Got rendezvous ack. This circuit is now ready for rendezvous."); circ->purpose = CIRCUIT_PURPOSE_C_REND_READY; return 0; } /* bob sent us a rendezvous cell, join the circs. */ int rend_client_receive_rendezvous(circuit_t *circ, const char *request, int request_len) { connection_t *apconn; crypt_path_t *hop; char keys[DIGEST_LEN+CPATH_KEY_MATERIAL_LEN]; if(circ->purpose != CIRCUIT_PURPOSE_C_REND_READY || !circ->build_state->pending_final_cpath) { log_fn(LOG_WARN,"Got rendezvous2 cell from Bob, but not expecting it. Closing."); circuit_mark_for_close(circ); return -1; } if (request_len != DH_KEY_LEN+DIGEST_LEN) { log_fn(LOG_WARN,"Incorrect length (%d) on RENDEZVOUS2 cell.",request_len); goto err; } /* first DH_KEY_LEN bytes are g^y from bob. Finish the dh handshake...*/ assert(circ->build_state && circ->build_state->pending_final_cpath); hop = circ->build_state->pending_final_cpath; assert(hop->handshake_state); if (crypto_dh_compute_secret(hop->handshake_state, request, DH_KEY_LEN, keys, DIGEST_LEN+CPATH_KEY_MATERIAL_LEN)<0) { log_fn(LOG_WARN, "Couldn't complete DH handshake"); goto err; } /* ... and set up cpath. */ if (circuit_init_cpath_crypto(hop, keys+DIGEST_LEN, 0)<0) goto err; /* Check whether the digest is right... */ if (memcmp(keys, request+DH_KEY_LEN, DIGEST_LEN)) { log_fn(LOG_WARN, "Incorrect digest of key material"); goto err; } crypto_dh_free(hop->handshake_state); hop->handshake_state = NULL; /* All is well. Extend the circuit. */ circ->purpose = CIRCUIT_PURPOSE_C_REND_JOINED; hop->state = CPATH_STATE_OPEN; /* set the windows to default. these are the windows * that alice thinks bob has. */ hop->package_window = CIRCWINDOW_START; hop->deliver_window = CIRCWINDOW_START; onion_append_to_cpath(&circ->cpath, hop); circ->build_state->pending_final_cpath = NULL; /* prevent double-free */ for(apconn = circ->p_streams; apconn; apconn = apconn->next_stream) { apconn->cpath_layer = circ->cpath->prev; /* now the last hop is different. be sure to send all the way. */ if(connection_ap_handshake_send_begin(apconn, circ) < 0) return -1; } return 0; err: circuit_mark_for_close(circ); return -1; } /* Find all the apconns in state AP_CONN_STATE_RENDDESC_WAIT that * are waiting on query. If success==1, move them to the next state. * If success==0, fail them. */ void rend_client_desc_fetched(char *query, int success) { connection_t **carray; connection_t *conn; int n, i; rend_cache_entry_t *entry; get_connection_array(&carray, &n); for (i = 0; i < n; ++i) { conn = carray[i]; if (conn->type != CONN_TYPE_AP || conn->state != AP_CONN_STATE_RENDDESC_WAIT) continue; if (rend_cmp_service_ids(conn->rend_query, query)) continue; /* great, this guy was waiting */ if(success || rend_cache_lookup_entry(conn->rend_query, &entry) == 1) { /* either this fetch worked, or it failed but there was a * valid entry from before which we should reuse */ log_fn(LOG_INFO,"Rend desc retrieved. Launching circuits."); conn->state = AP_CONN_STATE_CIRCUIT_WAIT; if (connection_ap_handshake_attach_circuit(conn) < 0) { /* it will never work */ log_fn(LOG_WARN,"attaching to a rend circ failed. Closing conn."); connection_mark_for_close(conn,0); } } else { /* 404, or fetch didn't get that far */ log_fn(LOG_WARN,"service id '%s' fetched failed, and not in cache. Closing conn.", query); connection_mark_for_close(conn,0); } } } int rend_cmp_service_ids(char *one, char *two) { return strcasecmp(one,two); } /* strdup a nickname for a random introduction * point of query. return NULL if error. */ char *rend_client_get_random_intro(char *query) { int i; smartlist_t *sl; char *choice; char *nickname; rend_cache_entry_t *entry; if(rend_cache_lookup_entry(query, &entry) < 1) { log_fn(LOG_WARN,"query '%s' didn't have valid rend desc in cache. Failing.", query); return NULL; } sl = smartlist_create(); /* add the intro point nicknames */ for(i=0;iparsed->n_intro_points;i++) smartlist_add(sl,entry->parsed->intro_points[i]); choice = smartlist_choose(sl); if(!choice) { smartlist_free(sl); return NULL; } nickname = tor_strdup(choice); smartlist_free(sl); return nickname; } /* If address is of the form "y.onion" with a well-formed handle y, * then put a '\0' after y, lower-case it, and return 0. * Else return -1 and change nothing. */ int rend_parse_rendezvous_address(char *address) { char *s; char query[REND_SERVICE_ID_LEN+1]; s = strrchr(address,'.'); if(!s) return -1; /* no dot */ if (strcasecmp(s+1,"onion")) return -1; /* not .onion */ *s = 0; /* null terminate it */ if(strlcpy(query, address, REND_SERVICE_ID_LEN+1) >= REND_SERVICE_ID_LEN+1) goto failed; tor_strlower(query); if(rend_valid_service_id(query)) { tor_strlower(address); return 0; /* success */ } failed: /* otherwise, return to previous state and return -1 */ *s = '.'; return -1; } /* Local Variables: mode:c indent-tabs-mode:nil c-basic-offset:2 End: */