diff options
Diffstat (limited to 'src/or/circuitbuild.c')
| -rw-r--r-- | src/or/circuitbuild.c | 261 |
1 files changed, 204 insertions, 57 deletions
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c index cb9c146fb7..79962e8dbb 100644 --- a/src/or/circuitbuild.c +++ b/src/or/circuitbuild.c @@ -9,11 +9,26 @@ * * \brief Implements the details of building circuits (by chosing paths, * constructing/sending create/extend cells, and so on). + * + * On the client side, this module handles launching circuits. Circuit + * launches are srtarted from circuit_establish_circuit(), called from + * circuit_launch_by_extend_info()). To choose the path the circuit will + * take, onion_extend_cpath() calls into a maze of node selection functions. + * + * Once the circuit is ready to be launched, the first hop is treated as a + * special case with circuit_handle_first_hop(), since it might need to open a + * channel. As the channel opens, and later as CREATED and RELAY_EXTENDED + * cells arrive, the client will invoke circuit_send_next_onion_skin() to send + * CREATE or RELAY_EXTEND cells. + * + * On the server side, this module also handles the logic of responding to + * RELAY_EXTEND requests, using circuit_extend(). **/ #define CIRCUITBUILD_PRIVATE #include "or.h" +#include "bridges.h" #include "channel.h" #include "circpathbias.h" #define CIRCUITBUILD_PRIVATE @@ -49,8 +64,9 @@ #include "transports.h" static channel_t * channel_connect_for_circuit(const tor_addr_t *addr, - uint16_t port, - const char *id_digest); + uint16_t port, + const char *id_digest, + const ed25519_public_key_t *ed_id); static int circuit_deliver_create_cell(circuit_t *circ, const create_cell_t *create_cell, int relayed); @@ -66,11 +82,12 @@ static int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice); */ static channel_t * channel_connect_for_circuit(const tor_addr_t *addr, uint16_t port, - const char *id_digest) + const char *id_digest, + const ed25519_public_key_t *ed_id) { channel_t *chan; - chan = channel_connect(addr, port, id_digest); + chan = channel_connect(addr, port, id_digest, ed_id); if (chan) command_setup_channel(chan); return chan; @@ -502,6 +519,13 @@ circuit_establish_circuit(uint8_t purpose, extend_info_t *exit_ei, int flags) return circ; } +/** Return the guard state associated with <b>circ</b>, which may be NULL. */ +circuit_guard_state_t * +origin_circuit_get_guard_state(origin_circuit_t *circ) +{ + return circ->guard_state; +} + /** Start establishing the first hop of our circuit. Figure out what * OR we should connect to, and if necessary start the connection to * it. If we're already connected, then send the 'create' cell. @@ -540,6 +564,7 @@ circuit_handle_first_hop(origin_circuit_t *circ) firsthop->extend_info->port)); n_chan = channel_get_for_extend(firsthop->extend_info->identity_digest, + &firsthop->extend_info->ed_identity, &firsthop->extend_info->addr, &msg, &should_launch); @@ -557,7 +582,8 @@ circuit_handle_first_hop(origin_circuit_t *circ) n_chan = channel_connect_for_circuit( &firsthop->extend_info->addr, firsthop->extend_info->port, - firsthop->extend_info->identity_digest); + firsthop->extend_info->identity_digest, + &firsthop->extend_info->ed_identity); if (!n_chan) { /* connect failed, forget the whole thing */ log_info(LD_CIRC,"connect to firsthop failed. Closing."); return -END_CIRC_REASON_CONNECTFAILED; @@ -866,6 +892,27 @@ circuit_pick_extend_handshake(uint8_t *cell_type_out, } } +/** + * Return true iff <b>purpose</b> is a purpose for a circuit which is + * allowed to have no guard configured, even if the circuit is multihop + * and guards are enabled. + */ +static int +circuit_purpose_may_omit_guard(int purpose) +{ + switch (purpose) { + case CIRCUIT_PURPOSE_TESTING: + case CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT: + /* Testing circuits may omit guards because they're measuring + * liveness or performance, and don't want guards to interfere. */ + return 1; + default: + /* All other multihop circuits should use guards if guards are + * enabled. */ + return 0; + } +} + /** This is the backbone function for building circuits. * * If circ's first hop is closed, then we need to build a create @@ -940,7 +987,37 @@ circuit_send_next_onion_skin(origin_circuit_t *circ) memset(&ec, 0, sizeof(ec)); if (!hop) { /* done building the circuit. whew. */ - circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN); + guard_usable_t r; + if (! circ->guard_state) { + if (circuit_get_cpath_len(circ) != 1 && + ! circuit_purpose_may_omit_guard(circ->base_.purpose) && + get_options()->UseEntryGuards) { + log_warn(LD_BUG, "%d-hop circuit %p with purpose %d has no " + "guard state", + circuit_get_cpath_len(circ), circ, circ->base_.purpose); + } + r = GUARD_USABLE_NOW; + } else { + r = entry_guard_succeeded(&circ->guard_state); + } + const int is_usable_for_streams = (r == GUARD_USABLE_NOW); + if (r == GUARD_USABLE_NOW) { + circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN); + } else if (r == GUARD_MAYBE_USABLE_LATER) { + // Wait till either a better guard succeeds, or till + // all better guards fail. + circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_GUARD_WAIT); + } else { + tor_assert_nonfatal(r == GUARD_USABLE_NEVER); + return - END_CIRC_REASON_INTERNAL; + } + + /* XXXX #21422 -- the rest of this branch needs careful thought! + * Some of the things here need to happen when a circuit becomes + * mechanically open; some need to happen when it is actually usable. + * I think I got them right, but more checking would be wise. -NM + */ + if (circuit_timeout_want_to_count_circ(circ)) { struct timeval end; long timediff; @@ -958,7 +1035,7 @@ circuit_send_next_onion_skin(origin_circuit_t *circ) "Assuming clock jump. Purpose %d (%s)", timediff, circ->base_.purpose, circuit_purpose_to_string(circ->base_.purpose)); - } else if (!circuit_build_times_disabled()) { + } else if (!circuit_build_times_disabled(get_options())) { /* Only count circuit times if the network is live */ if (circuit_build_times_network_check_live( get_circuit_build_times())) { @@ -982,7 +1059,8 @@ circuit_send_next_onion_skin(origin_circuit_t *circ) pathbias_count_build_success(circ); circuit_rep_hist_note_result(circ); - circuit_has_opened(circ); /* do other actions as necessary */ + if (is_usable_for_streams) + circuit_has_opened(circ); /* do other actions as necessary */ if (!have_completed_a_circuit() && !circ->build_state->onehop_tunnel) { const or_options_t *options = get_options(); @@ -1025,6 +1103,9 @@ circuit_send_next_onion_skin(origin_circuit_t *circ) ec.orport_ipv4.port = hop->extend_info->port; tor_addr_make_unspec(&ec.orport_ipv6.addr); memcpy(ec.node_id, hop->extend_info->identity_digest, DIGEST_LEN); + /* Set the ED25519 identity too -- it will only get included + * in the extend2 cell if we're configured to use it, though. */ + ed25519_pubkey_copy(&ec.ed_pubkey, &hop->extend_info->ed_identity); len = onion_skin_create(ec.create_cell.handshake_type, hop->extend_info, @@ -1143,7 +1224,7 @@ circuit_extend(cell_t *cell, circuit_t *circ) /* Check if they asked us for 0000..0000. We support using * an empty fingerprint for the first hop (e.g. for a bridge relay), - * but we don't want to let people send us extend cells for empty + * but we don't want to let clients send us extend cells for empty * fingerprints -- a) because it opens the user up to a mitm attack, * and b) because it lets an attacker force the relay to hold open a * new TLS connection for each extend request. */ @@ -1153,6 +1234,18 @@ circuit_extend(cell_t *cell, circuit_t *circ) return -1; } + /* Fill in ed_pubkey if it was not provided and we can infer it from + * our networkstatus */ + if (ed25519_public_key_is_zero(&ec.ed_pubkey)) { + const node_t *node = node_get_by_id((const char*)ec.node_id); + const ed25519_public_key_t *node_ed_id = NULL; + if (node && + node_supports_ed25519_link_authentication(node) && + (node_ed_id = node_get_ed25519_id(node))) { + ed25519_pubkey_copy(&ec.ed_pubkey, node_ed_id); + } + } + /* Next, check if we're being asked to connect to the hop that the * extend cell came from. There isn't any reason for that, and it can * assist circular-path attacks. */ @@ -1164,7 +1257,17 @@ circuit_extend(cell_t *cell, circuit_t *circ) return -1; } + /* Check the previous hop Ed25519 ID too */ + if (! ed25519_public_key_is_zero(&ec.ed_pubkey) && + ed25519_pubkey_eq(&ec.ed_pubkey, + &TO_OR_CIRCUIT(circ)->p_chan->ed25519_identity)) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Client asked me to extend back to the previous hop " + "(by Ed25519 ID)."); + } + n_chan = channel_get_for_extend((const char*)ec.node_id, + &ec.ed_pubkey, &ec.orport_ipv4.addr, &msg, &should_launch); @@ -1176,8 +1279,9 @@ circuit_extend(cell_t *cell, circuit_t *circ) circ->n_hop = extend_info_new(NULL /*nickname*/, (const char*)ec.node_id, - NULL /*onion_key*/, - NULL /*curve25519_key*/, + &ec.ed_pubkey, + NULL, /*onion_key*/ + NULL, /*curve25519_key*/ &ec.orport_ipv4.addr, ec.orport_ipv4.port); @@ -1190,7 +1294,8 @@ circuit_extend(cell_t *cell, circuit_t *circ) /* we should try to open a connection */ n_chan = channel_connect_for_circuit(&ec.orport_ipv4.addr, ec.orport_ipv4.port, - (const char*)ec.node_id); + (const char*)ec.node_id, + &ec.ed_pubkey); if (!n_chan) { log_info(LD_CIRC,"Launching n_chan failed. Closing circuit."); circuit_mark_for_close(circ, END_CIRC_REASON_CONNECTFAILED); @@ -1492,9 +1597,9 @@ circuit_get_unhandled_ports(time_t now) * If we're returning 0, set need_uptime and need_capacity to * indicate any requirements that the unhandled ports have. */ -int -circuit_all_predicted_ports_handled(time_t now, int *need_uptime, - int *need_capacity) +MOCK_IMPL(int, +circuit_all_predicted_ports_handled, (time_t now, int *need_uptime, + int *need_capacity)) { int i, enough; uint16_t *port; @@ -2026,7 +2131,8 @@ onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit_ei) return -1; } exit_ei = extend_info_from_node(node, 0); - tor_assert(exit_ei); + if (BUG(exit_ei == NULL)) + return -1; } state->chosen_exit = exit_ei; return 0; @@ -2182,9 +2288,14 @@ choose_good_middle_server(uint8_t purpose, * * If <b>state</b> is NULL, we're choosing a router to serve as an entry * guard, not for any particular circuit. + * + * Set *<b>guard_state_out</b> to information about the guard that + * we're selecting, which we'll use later to remember whether the + * guard worked or not. */ const node_t * -choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state) +choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state, + circuit_guard_state_t **guard_state_out) { const node_t *choice; smartlist_t *excluded; @@ -2199,7 +2310,8 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state) (purpose != CIRCUIT_PURPOSE_TESTING || options->BridgeRelay)) { /* This request is for an entry server to use for a regular circuit, * and we use entry guard nodes. Just return one of the guard nodes. */ - return choose_random_entry(state); + tor_assert(guard_state_out); + return guards_choose_guard(state, guard_state_out); } excluded = smartlist_new(); @@ -2209,25 +2321,6 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state) * family. */ nodelist_add_node_and_family(excluded, node); } - /* and exclude current entry guards and their families, - * unless we're in a test network, and excluding guards - * would exclude all nodes (i.e. we're in an incredibly small tor network, - * or we're using TestingAuthVoteGuard *). - * This is an incomplete fix, but is no worse than the previous behaviour, - * and only applies to minimal, testing tor networks - * (so it's no less secure) */ - /*XXXX++ use the using_as_guard flag to accomplish this.*/ - if (options->UseEntryGuards - && (!options->TestingTorNetwork || - smartlist_len(nodelist_get_list()) > smartlist_len(get_entry_guards()) - )) { - SMARTLIST_FOREACH(get_entry_guards(), const entry_guard_t *, entry, - { - if ((node = node_get_by_id(entry->identity))) { - nodelist_add_node_and_family(excluded, node); - } - }); - } if (state) { if (state->need_uptime) @@ -2283,7 +2376,8 @@ onion_extend_cpath(origin_circuit_t *circ) if (cur_len == state->desired_path_len - 1) { /* Picking last node */ info = extend_info_dup(state->chosen_exit); } else if (cur_len == 0) { /* picking first node */ - const node_t *r = choose_good_entry_server(purpose, state); + const node_t *r = choose_good_entry_server(purpose, state, + &circ->guard_state); if (r) { /* If we're a client, use the preferred address rather than the primary address, for potentially connecting to an IPv6 OR @@ -2291,14 +2385,14 @@ onion_extend_cpath(origin_circuit_t *circ) int client = (server_mode(get_options()) == 0); info = extend_info_from_node(r, client); /* Clients can fail to find an allowed address */ - tor_assert(info || client); + tor_assert_nonfatal(info || client); } } else { const node_t *r = choose_good_middle_server(purpose, state, circ->cpath, cur_len); if (r) { info = extend_info_from_node(r, 0); - tor_assert(info); + tor_assert_nonfatal(info); } } @@ -2341,19 +2435,23 @@ onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice) /** Allocate a new extend_info object based on the various arguments. */ extend_info_t * -extend_info_new(const char *nickname, const char *digest, +extend_info_new(const char *nickname, + const char *rsa_id_digest, + const ed25519_public_key_t *ed_id, crypto_pk_t *onion_key, - const curve25519_public_key_t *curve25519_key, + const curve25519_public_key_t *ntor_key, const tor_addr_t *addr, uint16_t port) { extend_info_t *info = tor_malloc_zero(sizeof(extend_info_t)); - memcpy(info->identity_digest, digest, DIGEST_LEN); + memcpy(info->identity_digest, rsa_id_digest, DIGEST_LEN); + if (ed_id && !ed25519_public_key_is_zero(ed_id)) + memcpy(&info->ed_identity, ed_id, sizeof(ed25519_public_key_t)); if (nickname) strlcpy(info->nickname, nickname, sizeof(info->nickname)); if (onion_key) info->onion_key = crypto_pk_dup_key(onion_key); - if (curve25519_key) - memcpy(&info->curve25519_onion_key, curve25519_key, + if (ntor_key) + memcpy(&info->curve25519_onion_key, ntor_key, sizeof(curve25519_public_key_t)); tor_addr_copy(&info->addr, addr); info->port = port; @@ -2403,20 +2501,35 @@ extend_info_from_node(const node_t *node, int for_direct_connect) return NULL; } + const ed25519_public_key_t *ed_pubkey = NULL; + + /* Don't send the ed25519 pubkey unless the target node actually supports + * authenticating with it. */ + if (node_supports_ed25519_link_authentication(node)) { + log_info(LD_CIRC, "Including Ed25519 ID for %s", node_describe(node)); + ed_pubkey = node_get_ed25519_id(node); + } else if (node_get_ed25519_id(node)) { + log_info(LD_CIRC, "Not including the ed25519 ID for %s, since it won't " + " be able to authenticate it.", + node_describe(node)); + } + if (valid_addr && node->ri) return extend_info_new(node->ri->nickname, - node->identity, - node->ri->onion_pkey, - node->ri->onion_curve25519_pkey, - &ap.addr, - ap.port); + node->identity, + ed_pubkey, + node->ri->onion_pkey, + node->ri->onion_curve25519_pkey, + &ap.addr, + ap.port); else if (valid_addr && node->rs && node->md) return extend_info_new(node->rs->nickname, - node->identity, - node->md->onion_pkey, - node->md->onion_curve25519_pkey, - &ap.addr, - ap.port); + node->identity, + ed_pubkey, + node->md->onion_pkey, + node->md->onion_curve25519_pkey, + &ap.addr, + ap.port); else return NULL; } @@ -2447,8 +2560,8 @@ extend_info_dup(extend_info_t *info) return newinfo; } -/** Return the routerinfo_t for the chosen exit router in <b>state</b>. - * If there is no chosen exit, or if we don't know the routerinfo_t for +/** Return the node_t for the chosen exit router in <b>state</b>. + * If there is no chosen exit, or if we don't know the node_t for * the chosen exit, return NULL. */ const node_t * @@ -2459,6 +2572,17 @@ build_state_get_exit_node(cpath_build_state_t *state) return node_get_by_id(state->chosen_exit->identity_digest); } +/** Return the RSA ID digest for the chosen exit router in <b>state</b>. + * If there is no chosen exit, return NULL. + */ +const uint8_t * +build_state_get_exit_rsa_id(cpath_build_state_t *state) +{ + if (!state || !state->chosen_exit) + return NULL; + return (const uint8_t *) state->chosen_exit->identity_digest; +} + /** Return the nickname for the chosen exit router in <b>state</b>. If * there is no chosen exit, or if we don't know the routerinfo_t for the * chosen exit, return NULL. @@ -2551,3 +2675,26 @@ extend_info_has_preferred_onion_key(const extend_info_t* ei) return extend_info_supports_ntor(ei); } +/** Find the circuits that are waiting to find out whether their guards are + * usable, and if any are ready to become usable, mark them open and try + * attaching streams as appropriate. */ +void +circuit_upgrade_circuits_from_guard_wait(void) +{ + smartlist_t *to_upgrade = + circuit_find_circuits_to_upgrade_from_guard_wait(); + + if (to_upgrade == NULL) + return; + + log_info(LD_GUARD, "Upgrading %d circuits from 'waiting for better guard' " + "to 'open'.", smartlist_len(to_upgrade)); + + SMARTLIST_FOREACH_BEGIN(to_upgrade, origin_circuit_t *, circ) { + circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN); + circuit_has_opened(circ); + } SMARTLIST_FOREACH_END(circ); + + smartlist_free(to_upgrade); +} + |