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- /* Copyright (c) 2016-2017, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file hs_client.c
- * \brief Implement next generation hidden service client functionality
- **/
- #define HS_CLIENT_PRIVATE
- #include "or.h"
- #include "hs_circuit.h"
- #include "hs_ident.h"
- #include "connection_edge.h"
- #include "container.h"
- #include "rendclient.h"
- #include "hs_descriptor.h"
- #include "hs_cache.h"
- #include "hs_cell.h"
- #include "hs_ident.h"
- #include "config.h"
- #include "directory.h"
- #include "hs_client.h"
- #include "hs_control.h"
- #include "router.h"
- #include "routerset.h"
- #include "circuitlist.h"
- #include "circuituse.h"
- #include "connection.h"
- #include "nodelist.h"
- #include "circpathbias.h"
- #include "connection.h"
- #include "hs_ntor.h"
- #include "circuitbuild.h"
- #include "networkstatus.h"
- #include "reasons.h"
- /* Return a human-readable string for the client fetch status code. */
- static const char *
- fetch_status_to_string(hs_client_fetch_status_t status)
- {
- switch (status) {
- case HS_CLIENT_FETCH_ERROR:
- return "Internal error";
- case HS_CLIENT_FETCH_LAUNCHED:
- return "Descriptor fetch launched";
- case HS_CLIENT_FETCH_HAVE_DESC:
- return "Already have descriptor";
- case HS_CLIENT_FETCH_NO_HSDIRS:
- return "No more HSDir available to query";
- case HS_CLIENT_FETCH_NOT_ALLOWED:
- return "Fetching descriptors is not allowed";
- case HS_CLIENT_FETCH_MISSING_INFO:
- return "Missing directory information";
- case HS_CLIENT_FETCH_PENDING:
- return "Pending descriptor fetch";
- default:
- return "(Unknown client fetch status code)";
- }
- }
- /* Return true iff tor should close the SOCKS request(s) for the descriptor
- * fetch that ended up with this given status code. */
- static int
- fetch_status_should_close_socks(hs_client_fetch_status_t status)
- {
- switch (status) {
- case HS_CLIENT_FETCH_NO_HSDIRS:
- /* No more HSDir to query, we can't complete the SOCKS request(s). */
- case HS_CLIENT_FETCH_ERROR:
- /* The fetch triggered an internal error. */
- case HS_CLIENT_FETCH_NOT_ALLOWED:
- /* Client is not allowed to fetch (FetchHidServDescriptors 0). */
- goto close;
- case HS_CLIENT_FETCH_MISSING_INFO:
- case HS_CLIENT_FETCH_HAVE_DESC:
- case HS_CLIENT_FETCH_PENDING:
- case HS_CLIENT_FETCH_LAUNCHED:
- /* The rest doesn't require tor to close the SOCKS request(s). */
- goto no_close;
- }
- no_close:
- return 0;
- close:
- return 1;
- }
- /* Cancel all descriptor fetches currently in progress. */
- static void
- cancel_descriptor_fetches(void)
- {
- smartlist_t *conns =
- connection_list_by_type_state(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC);
- SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
- const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident;
- if (BUG(ident == NULL)) {
- /* A directory connection fetching a service descriptor can't have an
- * empty hidden service identifier. */
- continue;
- }
- log_debug(LD_REND, "Marking for close a directory connection fetching "
- "a hidden service descriptor for service %s.",
- safe_str_client(ed25519_fmt(&ident->identity_pk)));
- connection_mark_for_close(conn);
- } SMARTLIST_FOREACH_END(conn);
- /* No ownership of the objects in this list. */
- smartlist_free(conns);
- log_info(LD_REND, "Hidden service client descriptor fetches cancelled.");
- }
- /* Get all connections that are waiting on a circuit and flag them back to
- * waiting for a hidden service descriptor for the given service key
- * service_identity_pk. */
- static void
- flag_all_conn_wait_desc(const ed25519_public_key_t *service_identity_pk)
- {
- tor_assert(service_identity_pk);
- smartlist_t *conns =
- connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_CIRCUIT_WAIT);
- SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
- edge_connection_t *edge_conn;
- if (BUG(!CONN_IS_EDGE(conn))) {
- continue;
- }
- edge_conn = TO_EDGE_CONN(conn);
- if (edge_conn->hs_ident &&
- ed25519_pubkey_eq(&edge_conn->hs_ident->identity_pk,
- service_identity_pk)) {
- connection_ap_mark_as_non_pending_circuit(TO_ENTRY_CONN(conn));
- conn->state = AP_CONN_STATE_RENDDESC_WAIT;
- }
- } SMARTLIST_FOREACH_END(conn);
- smartlist_free(conns);
- }
- /* Remove tracked HSDir requests from our history for this hidden service
- * identity public key. */
- static void
- purge_hid_serv_request(const ed25519_public_key_t *identity_pk)
- {
- char base64_blinded_pk[ED25519_BASE64_LEN + 1];
- ed25519_public_key_t blinded_pk;
- tor_assert(identity_pk);
- /* Get blinded pubkey of hidden service. It is possible that we just moved
- * to a new time period meaning that we won't be able to purge the request
- * from the previous time period. That is fine because they will expire at
- * some point and we don't care about those anymore. */
- hs_build_blinded_pubkey(identity_pk, NULL, 0,
- hs_get_time_period_num(0), &blinded_pk);
- if (BUG(ed25519_public_to_base64(base64_blinded_pk, &blinded_pk) < 0)) {
- return;
- }
- /* Purge last hidden service request from cache for this blinded key. */
- hs_purge_hid_serv_from_last_hid_serv_requests(base64_blinded_pk);
- }
- /* Return true iff there is at least one pending directory descriptor request
- * for the service identity_pk. */
- static int
- directory_request_is_pending(const ed25519_public_key_t *identity_pk)
- {
- int ret = 0;
- smartlist_t *conns =
- connection_list_by_type_purpose(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC);
- SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
- const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident;
- if (BUG(ident == NULL)) {
- /* A directory connection fetching a service descriptor can't have an
- * empty hidden service identifier. */
- continue;
- }
- if (!ed25519_pubkey_eq(identity_pk, &ident->identity_pk)) {
- continue;
- }
- ret = 1;
- break;
- } SMARTLIST_FOREACH_END(conn);
- /* No ownership of the objects in this list. */
- smartlist_free(conns);
- return ret;
- }
- /* We failed to fetch a descriptor for the service with <b>identity_pk</b>
- * because of <b>status</b>. Find all pending SOCKS connections for this
- * service that are waiting on the descriptor and close them with
- * <b>reason</b>. */
- static void
- close_all_socks_conns_waiting_for_desc(const ed25519_public_key_t *identity_pk,
- hs_client_fetch_status_t status,
- int reason)
- {
- unsigned int count = 0;
- time_t now = approx_time();
- smartlist_t *conns =
- connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT);
- SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
- entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn);
- const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
- /* Only consider the entry connections that matches the service for which
- * we tried to get the descriptor */
- if (!edge_conn->hs_ident ||
- !ed25519_pubkey_eq(identity_pk,
- &edge_conn->hs_ident->identity_pk)) {
- continue;
- }
- assert_connection_ok(base_conn, now);
- /* Unattach the entry connection which will close for the reason. */
- connection_mark_unattached_ap(entry_conn, reason);
- count++;
- } SMARTLIST_FOREACH_END(base_conn);
- if (count > 0) {
- char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
- hs_build_address(identity_pk, HS_VERSION_THREE, onion_address);
- log_notice(LD_REND, "Closed %u streams for service %s.onion "
- "for reason %s. Fetch status: %s.",
- count, safe_str_client(onion_address),
- stream_end_reason_to_string(reason),
- fetch_status_to_string(status));
- }
- /* No ownership of the object(s) in this list. */
- smartlist_free(conns);
- }
- /* Find all pending SOCKS connection waiting for a descriptor and retry them
- * all. This is called when the directory information changed. */
- static void
- retry_all_socks_conn_waiting_for_desc(void)
- {
- smartlist_t *conns =
- connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT);
- SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
- hs_client_fetch_status_t status;
- const edge_connection_t *edge_conn =
- ENTRY_TO_EDGE_CONN(TO_ENTRY_CONN(base_conn));
- /* Ignore non HS or non v3 connection. */
- if (edge_conn->hs_ident == NULL) {
- continue;
- }
- /* In this loop, we will possibly try to fetch a descriptor for the
- * pending connections because we just got more directory information.
- * However, the refetch process can cleanup all SOCKS request so the same
- * service if an internal error happens. Thus, we can end up with closed
- * connections in our list. */
- if (base_conn->marked_for_close) {
- continue;
- }
- /* XXX: There is an optimization we could do which is that for a service
- * key, we could check if we can fetch and remember that decision. */
- /* Order a refetch in case it works this time. */
- status = hs_client_refetch_hsdesc(&edge_conn->hs_ident->identity_pk);
- if (BUG(status == HS_CLIENT_FETCH_HAVE_DESC)) {
- /* This case is unique because it can NOT happen in theory. Once we get
- * a new descriptor, the HS client subsystem is notified immediately and
- * the connections waiting for it are handled which means the state will
- * change from renddesc wait state. Log this and continue to next
- * connection. */
- continue;
- }
- /* In the case of an error, either all SOCKS connections have been
- * closed or we are still missing directory information. Leave the
- * connection in renddesc wait state so when we get more info, we'll be
- * able to try it again. */
- } SMARTLIST_FOREACH_END(base_conn);
- /* We don't have ownership of those objects. */
- smartlist_free(conns);
- }
- /* A v3 HS circuit successfully connected to the hidden service. Update the
- * stream state at <b>hs_conn_ident</b> appropriately. */
- static void
- note_connection_attempt_succeeded(const hs_ident_edge_conn_t *hs_conn_ident)
- {
- tor_assert(hs_conn_ident);
- /* Remove from the hid serv cache all requests for that service so we can
- * query the HSDir again later on for various reasons. */
- purge_hid_serv_request(&hs_conn_ident->identity_pk);
- /* The v2 subsystem cleans up the intro point time out flag at this stage.
- * We don't try to do it here because we still need to keep intact the intro
- * point state for future connections. Even though we are able to connect to
- * the service, doesn't mean we should reset the timed out intro points.
- *
- * It is not possible to have successfully connected to an intro point
- * present in our cache that was on error or timed out. Every entry in that
- * cache have a 2 minutes lifetime so ultimately the intro point(s) state
- * will be reset and thus possible to be retried. */
- }
- /* Given the pubkey of a hidden service in <b>onion_identity_pk</b>, fetch its
- * descriptor by launching a dir connection to <b>hsdir</b>. Return a
- * hs_client_fetch_status_t status code depending on how it went. */
- static hs_client_fetch_status_t
- directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
- const routerstatus_t *hsdir)
- {
- uint64_t current_time_period = hs_get_time_period_num(0);
- ed25519_public_key_t blinded_pubkey;
- char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
- hs_ident_dir_conn_t hs_conn_dir_ident;
- int retval;
- tor_assert(hsdir);
- tor_assert(onion_identity_pk);
- /* Get blinded pubkey */
- hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
- current_time_period, &blinded_pubkey);
- /* ...and base64 it. */
- retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
- if (BUG(retval < 0)) {
- return HS_CLIENT_FETCH_ERROR;
- }
- /* Copy onion pk to a dir_ident so that we attach it to the dir conn */
- hs_ident_dir_conn_init(onion_identity_pk, &blinded_pubkey,
- &hs_conn_dir_ident);
- /* Setup directory request */
- directory_request_t *req =
- directory_request_new(DIR_PURPOSE_FETCH_HSDESC);
- directory_request_set_routerstatus(req, hsdir);
- directory_request_set_indirection(req, DIRIND_ANONYMOUS);
- directory_request_set_resource(req, base64_blinded_pubkey);
- directory_request_fetch_set_hs_ident(req, &hs_conn_dir_ident);
- directory_initiate_request(req);
- directory_request_free(req);
- log_info(LD_REND, "Descriptor fetch request for service %s with blinded "
- "key %s to directory %s",
- safe_str_client(ed25519_fmt(onion_identity_pk)),
- safe_str_client(base64_blinded_pubkey),
- safe_str_client(routerstatus_describe(hsdir)));
- /* Fire a REQUESTED event on the control port. */
- hs_control_desc_event_requested(onion_identity_pk, base64_blinded_pubkey,
- hsdir);
- /* Cleanup memory. */
- memwipe(&blinded_pubkey, 0, sizeof(blinded_pubkey));
- memwipe(base64_blinded_pubkey, 0, sizeof(base64_blinded_pubkey));
- memwipe(&hs_conn_dir_ident, 0, sizeof(hs_conn_dir_ident));
- return HS_CLIENT_FETCH_LAUNCHED;
- }
- /** Return the HSDir we should use to fetch the descriptor of the hidden
- * service with identity key <b>onion_identity_pk</b>. */
- STATIC routerstatus_t *
- pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk)
- {
- int retval;
- char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
- uint64_t current_time_period = hs_get_time_period_num(0);
- smartlist_t *responsible_hsdirs;
- ed25519_public_key_t blinded_pubkey;
- routerstatus_t *hsdir_rs = NULL;
- tor_assert(onion_identity_pk);
- responsible_hsdirs = smartlist_new();
- /* Get blinded pubkey of hidden service */
- hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
- current_time_period, &blinded_pubkey);
- /* ...and base64 it. */
- retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
- if (BUG(retval < 0)) {
- return NULL;
- }
- /* Get responsible hsdirs of service for this time period */
- hs_get_responsible_hsdirs(&blinded_pubkey, current_time_period,
- 0, 1, responsible_hsdirs);
- log_debug(LD_REND, "Found %d responsible HSDirs and about to pick one.",
- smartlist_len(responsible_hsdirs));
- /* Pick an HSDir from the responsible ones. The ownership of
- * responsible_hsdirs is given to this function so no need to free it. */
- hsdir_rs = hs_pick_hsdir(responsible_hsdirs, base64_blinded_pubkey);
- return hsdir_rs;
- }
- /** Fetch a v3 descriptor using the given <b>onion_identity_pk</b>.
- *
- * On success, HS_CLIENT_FETCH_LAUNCHED is returned. Otherwise, an error from
- * hs_client_fetch_status_t is returned. */
- MOCK_IMPL(STATIC hs_client_fetch_status_t,
- fetch_v3_desc, (const ed25519_public_key_t *onion_identity_pk))
- {
- routerstatus_t *hsdir_rs =NULL;
- tor_assert(onion_identity_pk);
- hsdir_rs = pick_hsdir_v3(onion_identity_pk);
- if (!hsdir_rs) {
- log_info(LD_REND, "Couldn't pick a v3 hsdir.");
- return HS_CLIENT_FETCH_NO_HSDIRS;
- }
- return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs);
- }
- /* Make sure that the given v3 origin circuit circ is a valid correct
- * introduction circuit. This will BUG() on any problems and hard assert if
- * the anonymity of the circuit is not ok. Return 0 on success else -1 where
- * the circuit should be mark for closed immediately. */
- static int
- intro_circ_is_ok(const origin_circuit_t *circ)
- {
- int ret = 0;
- tor_assert(circ);
- if (BUG(TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCING &&
- TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT &&
- TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACKED)) {
- ret = -1;
- }
- if (BUG(circ->hs_ident == NULL)) {
- ret = -1;
- }
- if (BUG(!hs_ident_intro_circ_is_valid(circ->hs_ident))) {
- ret = -1;
- }
- /* This can stop the tor daemon but we want that since if we don't have
- * anonymity on this circuit, something went really wrong. */
- assert_circ_anonymity_ok(circ, get_options());
- return ret;
- }
- /* Find a descriptor intro point object that matches the given ident in the
- * given descriptor desc. Return NULL if not found. */
- static const hs_desc_intro_point_t *
- find_desc_intro_point_by_ident(const hs_ident_circuit_t *ident,
- const hs_descriptor_t *desc)
- {
- const hs_desc_intro_point_t *intro_point = NULL;
- tor_assert(ident);
- tor_assert(desc);
- SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
- const hs_desc_intro_point_t *, ip) {
- if (ed25519_pubkey_eq(&ident->intro_auth_pk,
- &ip->auth_key_cert->signed_key)) {
- intro_point = ip;
- break;
- }
- } SMARTLIST_FOREACH_END(ip);
- return intro_point;
- }
- /* Find a descriptor intro point object from the descriptor object desc that
- * matches the given legacy identity digest in legacy_id. Return NULL if not
- * found. */
- static hs_desc_intro_point_t *
- find_desc_intro_point_by_legacy_id(const char *legacy_id,
- const hs_descriptor_t *desc)
- {
- hs_desc_intro_point_t *ret_ip = NULL;
- tor_assert(legacy_id);
- tor_assert(desc);
- /* We will go over every intro point and try to find which one is linked to
- * that circuit. Those lists are small so it's not that expensive. */
- SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
- hs_desc_intro_point_t *, ip) {
- SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
- const hs_desc_link_specifier_t *, lspec) {
- /* Not all tor node have an ed25519 identity key so we still rely on the
- * legacy identity digest. */
- if (lspec->type != LS_LEGACY_ID) {
- continue;
- }
- if (fast_memneq(legacy_id, lspec->u.legacy_id, DIGEST_LEN)) {
- break;
- }
- /* Found it. */
- ret_ip = ip;
- goto end;
- } SMARTLIST_FOREACH_END(lspec);
- } SMARTLIST_FOREACH_END(ip);
- end:
- return ret_ip;
- }
- /* Send an INTRODUCE1 cell along the intro circuit and populate the rend
- * circuit identifier with the needed key material for the e2e encryption.
- * Return 0 on success, -1 if there is a transient error such that an action
- * has been taken to recover and -2 if there is a permanent error indicating
- * that both circuits were closed. */
- static int
- send_introduce1(origin_circuit_t *intro_circ,
- origin_circuit_t *rend_circ)
- {
- int status;
- char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
- const ed25519_public_key_t *service_identity_pk = NULL;
- const hs_desc_intro_point_t *ip;
- tor_assert(rend_circ);
- if (intro_circ_is_ok(intro_circ) < 0) {
- goto perm_err;
- }
- service_identity_pk = &intro_circ->hs_ident->identity_pk;
- /* For logging purposes. There will be a time where the hs_ident will have a
- * version number but for now there is none because it's all v3. */
- hs_build_address(service_identity_pk, HS_VERSION_THREE, onion_address);
- log_info(LD_REND, "Sending INTRODUCE1 cell to service %s on circuit %u",
- safe_str_client(onion_address), TO_CIRCUIT(intro_circ)->n_circ_id);
- /* 1) Get descriptor from our cache. */
- const hs_descriptor_t *desc =
- hs_cache_lookup_as_client(service_identity_pk);
- if (desc == NULL || !hs_client_any_intro_points_usable(service_identity_pk,
- desc)) {
- log_info(LD_REND, "Request to %s %s. Trying to fetch a new descriptor.",
- safe_str_client(onion_address),
- (desc) ? "didn't have usable intro points" :
- "didn't have a descriptor");
- hs_client_refetch_hsdesc(service_identity_pk);
- /* We just triggered a refetch, make sure every connections are back
- * waiting for that descriptor. */
- flag_all_conn_wait_desc(service_identity_pk);
- /* We just asked for a refetch so this is a transient error. */
- goto tran_err;
- }
- /* We need to find which intro point in the descriptor we are connected to
- * on intro_circ. */
- ip = find_desc_intro_point_by_ident(intro_circ->hs_ident, desc);
- if (BUG(ip == NULL)) {
- /* If we can find a descriptor from this introduction circuit ident, we
- * must have a valid intro point object. Permanent error. */
- goto perm_err;
- }
- /* Send the INTRODUCE1 cell. */
- if (hs_circ_send_introduce1(intro_circ, rend_circ, ip,
- desc->subcredential) < 0) {
- /* Unable to send the cell, the intro circuit has been marked for close so
- * this is a permanent error. */
- tor_assert_nonfatal(TO_CIRCUIT(intro_circ)->marked_for_close);
- goto perm_err;
- }
- /* Cell has been sent successfully. Copy the introduction point
- * authentication and encryption key in the rendezvous circuit identifier so
- * we can compute the ntor keys when we receive the RENDEZVOUS2 cell. */
- memcpy(&rend_circ->hs_ident->intro_enc_pk, &ip->enc_key,
- sizeof(rend_circ->hs_ident->intro_enc_pk));
- ed25519_pubkey_copy(&rend_circ->hs_ident->intro_auth_pk,
- &intro_circ->hs_ident->intro_auth_pk);
- /* Now, we wait for an ACK or NAK on this circuit. */
- circuit_change_purpose(TO_CIRCUIT(intro_circ),
- CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT);
- /* Set timestamp_dirty, because circuit_expire_building expects it to
- * specify when a circuit entered the _C_INTRODUCE_ACK_WAIT state. */
- TO_CIRCUIT(intro_circ)->timestamp_dirty = time(NULL);
- pathbias_count_use_attempt(intro_circ);
- /* Success. */
- status = 0;
- goto end;
- perm_err:
- /* Permanent error: it is possible that the intro circuit was closed prior
- * because we weren't able to send the cell. Make sure we don't double close
- * it which would result in a warning. */
- if (!TO_CIRCUIT(intro_circ)->marked_for_close) {
- circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_INTERNAL);
- }
- circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_INTERNAL);
- status = -2;
- goto end;
- tran_err:
- status = -1;
- end:
- memwipe(onion_address, 0, sizeof(onion_address));
- return status;
- }
- /* Using the introduction circuit circ, setup the authentication key of the
- * intro point this circuit has extended to. */
- static void
- setup_intro_circ_auth_key(origin_circuit_t *circ)
- {
- const hs_descriptor_t *desc;
- const hs_desc_intro_point_t *ip;
- tor_assert(circ);
- desc = hs_cache_lookup_as_client(&circ->hs_ident->identity_pk);
- if (BUG(desc == NULL)) {
- /* Opening intro circuit without the descriptor is no good... */
- goto end;
- }
- /* We will go over every intro point and try to find which one is linked to
- * that circuit. Those lists are small so it's not that expensive. */
- ip = find_desc_intro_point_by_legacy_id(
- circ->build_state->chosen_exit->identity_digest, desc);
- if (ip) {
- /* We got it, copy its authentication key to the identifier. */
- ed25519_pubkey_copy(&circ->hs_ident->intro_auth_pk,
- &ip->auth_key_cert->signed_key);
- goto end;
- }
- /* Reaching this point means we didn't find any intro point for this circuit
- * which is not suppose to happen. */
- tor_assert_nonfatal_unreached();
- end:
- return;
- }
- /* Called when an introduction circuit has opened. */
- static void
- client_intro_circ_has_opened(origin_circuit_t *circ)
- {
- tor_assert(circ);
- tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
- log_info(LD_REND, "Introduction circuit %u has opened. Attaching streams.",
- (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
- /* This is an introduction circuit so we'll attach the correct
- * authentication key to the circuit identifier so it can be identified
- * properly later on. */
- setup_intro_circ_auth_key(circ);
- connection_ap_attach_pending(1);
- }
- /* Called when a rendezvous circuit has opened. */
- static void
- client_rendezvous_circ_has_opened(origin_circuit_t *circ)
- {
- tor_assert(circ);
- tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND);
- const extend_info_t *rp_ei = circ->build_state->chosen_exit;
- /* Check that we didn't accidentally choose a node that does not understand
- * the v3 rendezvous protocol */
- if (rp_ei) {
- const node_t *rp_node = node_get_by_id(rp_ei->identity_digest);
- if (rp_node) {
- if (BUG(!node_supports_v3_rendezvous_point(rp_node))) {
- return;
- }
- }
- }
- log_info(LD_REND, "Rendezvous circuit has opened to %s.",
- safe_str_client(extend_info_describe(rp_ei)));
- /* Ignore returned value, nothing we can really do. On failure, the circuit
- * will be marked for close. */
- hs_circ_send_establish_rendezvous(circ);
- /* Register rend circuit in circuitmap if it's still alive. */
- if (!TO_CIRCUIT(circ)->marked_for_close) {
- hs_circuitmap_register_rend_circ_client_side(circ,
- circ->hs_ident->rendezvous_cookie);
- }
- }
- /* This is an helper function that convert a descriptor intro point object ip
- * to a newly allocated extend_info_t object fully initialized. Return NULL if
- * we can't convert it for which chances are that we are missing or malformed
- * link specifiers. */
- STATIC extend_info_t *
- desc_intro_point_to_extend_info(const hs_desc_intro_point_t *ip)
- {
- extend_info_t *ei;
- smartlist_t *lspecs = smartlist_new();
- tor_assert(ip);
- /* We first encode the descriptor link specifiers into the binary
- * representation which is a trunnel object. */
- SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
- const hs_desc_link_specifier_t *, desc_lspec) {
- link_specifier_t *lspec = hs_desc_lspec_to_trunnel(desc_lspec);
- smartlist_add(lspecs, lspec);
- } SMARTLIST_FOREACH_END(desc_lspec);
- /* Explicitly put the direct connection option to 0 because this is client
- * side and there is no such thing as a non anonymous client. */
- ei = hs_get_extend_info_from_lspecs(lspecs, &ip->onion_key, 0);
- SMARTLIST_FOREACH(lspecs, link_specifier_t *, ls, link_specifier_free(ls));
- smartlist_free(lspecs);
- return ei;
- }
- /* Return true iff the intro point ip for the service service_pk is usable.
- * This function checks if the intro point is in the client intro state cache
- * and checks at the failures. It is considered usable if:
- * - No error happened (INTRO_POINT_FAILURE_GENERIC)
- * - It is not flagged as timed out (INTRO_POINT_FAILURE_TIMEOUT)
- * - The unreachable count is lower than
- * MAX_INTRO_POINT_REACHABILITY_FAILURES (INTRO_POINT_FAILURE_UNREACHABLE)
- */
- static int
- intro_point_is_usable(const ed25519_public_key_t *service_pk,
- const hs_desc_intro_point_t *ip)
- {
- const hs_cache_intro_state_t *state;
- tor_assert(service_pk);
- tor_assert(ip);
- state = hs_cache_client_intro_state_find(service_pk,
- &ip->auth_key_cert->signed_key);
- if (state == NULL) {
- /* This means we've never encountered any problem thus usable. */
- goto usable;
- }
- if (state->error) {
- log_info(LD_REND, "Intro point with auth key %s had an error. Not usable",
- safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
- goto not_usable;
- }
- if (state->timed_out) {
- log_info(LD_REND, "Intro point with auth key %s timed out. Not usable",
- safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
- goto not_usable;
- }
- if (state->unreachable_count >= MAX_INTRO_POINT_REACHABILITY_FAILURES) {
- log_info(LD_REND, "Intro point with auth key %s unreachable. Not usable",
- safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
- goto not_usable;
- }
- usable:
- return 1;
- not_usable:
- return 0;
- }
- /* Using a descriptor desc, return a newly allocated extend_info_t object of a
- * randomly picked introduction point from its list. Return NULL if none are
- * usable. */
- STATIC extend_info_t *
- client_get_random_intro(const ed25519_public_key_t *service_pk)
- {
- extend_info_t *ei = NULL, *ei_excluded = NULL;
- smartlist_t *usable_ips = NULL;
- const hs_descriptor_t *desc;
- const hs_desc_encrypted_data_t *enc_data;
- const or_options_t *options = get_options();
- /* Calculate the onion address for logging purposes */
- char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
- tor_assert(service_pk);
- desc = hs_cache_lookup_as_client(service_pk);
- /* Assume the service is v3 if the descriptor is missing. This is ok,
- * because we only use the address in log messages */
- hs_build_address(service_pk,
- desc ? desc->plaintext_data.version : HS_VERSION_THREE,
- onion_address);
- if (desc == NULL || !hs_client_any_intro_points_usable(service_pk,
- desc)) {
- log_info(LD_REND, "Unable to randomly select an introduction point "
- "for service %s because descriptor %s. We can't connect.",
- safe_str_client(onion_address),
- (desc) ? "doesn't have any usable intro points"
- : "is missing (assuming v3 onion address)");
- goto end;
- }
- enc_data = &desc->encrypted_data;
- usable_ips = smartlist_new();
- smartlist_add_all(usable_ips, enc_data->intro_points);
- while (smartlist_len(usable_ips) != 0) {
- int idx;
- const hs_desc_intro_point_t *ip;
- /* Pick a random intro point and immediately remove it from the usable
- * list so we don't pick it again if we have to iterate more. */
- idx = crypto_rand_int(smartlist_len(usable_ips));
- ip = smartlist_get(usable_ips, idx);
- smartlist_del(usable_ips, idx);
- /* We need to make sure we have a usable intro points which is in a good
- * state in our cache. */
- if (!intro_point_is_usable(service_pk, ip)) {
- continue;
- }
- /* Generate an extend info object from the intro point object. */
- ei = desc_intro_point_to_extend_info(ip);
- if (ei == NULL) {
- /* We can get here for instance if the intro point is a private address
- * and we aren't allowed to extend to those. */
- log_info(LD_REND, "Unable to select introduction point with auth key %s "
- "for service %s, because we could not extend to it.",
- safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)),
- safe_str_client(onion_address));
- continue;
- }
- /* Test the pick against ExcludeNodes. */
- if (routerset_contains_extendinfo(options->ExcludeNodes, ei)) {
- /* If this pick is in the ExcludeNodes list, we keep its reference so if
- * we ever end up not being able to pick anything else and StrictNodes is
- * unset, we'll use it. */
- if (ei_excluded) {
- /* If something was already here free it. After the loop is gone we
- * will examine the last excluded intro point, and that's fine since
- * that's random anyway */
- extend_info_free(ei_excluded);
- }
- ei_excluded = ei;
- continue;
- }
- /* Good pick! Let's go with this. */
- goto end;
- }
- /* Reaching this point means a couple of things. Either we can't use any of
- * the intro point listed because the IP address can't be extended to or it
- * is listed in the ExcludeNodes list. In the later case, if StrictNodes is
- * set, we are forced to not use anything. */
- ei = ei_excluded;
- if (options->StrictNodes) {
- log_warn(LD_REND, "Every introduction point for service %s is in the "
- "ExcludeNodes set and StrictNodes is set. We can't connect.",
- safe_str_client(onion_address));
- extend_info_free(ei);
- ei = NULL;
- } else {
- log_fn(LOG_PROTOCOL_WARN, LD_REND, "Every introduction point for service "
- "%s is unusable or we can't extend to it. We can't connect.",
- safe_str_client(onion_address));
- }
- end:
- smartlist_free(usable_ips);
- memwipe(onion_address, 0, sizeof(onion_address));
- return ei;
- }
- /* For this introduction circuit, we'll look at if we have any usable
- * introduction point left for this service. If so, we'll use the circuit to
- * re-extend to a new intro point. Else, we'll close the circuit and its
- * corresponding rendezvous circuit. Return 0 if we are re-extending else -1
- * if we are closing the circuits.
- *
- * This is called when getting an INTRODUCE_ACK cell with a NACK. */
- static int
- close_or_reextend_intro_circ(origin_circuit_t *intro_circ)
- {
- int ret = -1;
- const hs_descriptor_t *desc;
- origin_circuit_t *rend_circ;
- tor_assert(intro_circ);
- desc = hs_cache_lookup_as_client(&intro_circ->hs_ident->identity_pk);
- if (BUG(desc == NULL)) {
- /* We can't continue without a descriptor. */
- goto close;
- }
- /* We still have the descriptor, great! Let's try to see if we can
- * re-extend by looking up if there are any usable intro points. */
- if (!hs_client_any_intro_points_usable(&intro_circ->hs_ident->identity_pk,
- desc)) {
- goto close;
- }
- /* Try to re-extend now. */
- if (hs_client_reextend_intro_circuit(intro_circ) < 0) {
- goto close;
- }
- /* Success on re-extending. Don't return an error. */
- ret = 0;
- goto end;
- close:
- /* Change the intro circuit purpose before so we don't report an intro point
- * failure again triggering an extra descriptor fetch. The circuit can
- * already be closed on failure to re-extend. */
- if (!TO_CIRCUIT(intro_circ)->marked_for_close) {
- circuit_change_purpose(TO_CIRCUIT(intro_circ),
- CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
- circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED);
- }
- /* Close the related rendezvous circuit. */
- rend_circ = hs_circuitmap_get_rend_circ_client_side(
- intro_circ->hs_ident->rendezvous_cookie);
- /* The rendezvous circuit might have collapsed while the INTRODUCE_ACK was
- * inflight so we can't expect one every time. */
- if (rend_circ) {
- circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_FINISHED);
- }
- end:
- return ret;
- }
- /* Called when we get an INTRODUCE_ACK success status code. Do the appropriate
- * actions for the rendezvous point and finally close intro_circ. */
- static void
- handle_introduce_ack_success(origin_circuit_t *intro_circ)
- {
- origin_circuit_t *rend_circ = NULL;
- tor_assert(intro_circ);
- log_info(LD_REND, "Received INTRODUCE_ACK ack! Informing rendezvous");
- /* Get the rendezvous circuit for this rendezvous cookie. */
- uint8_t *rendezvous_cookie = intro_circ->hs_ident->rendezvous_cookie;
- rend_circ =
- hs_circuitmap_get_established_rend_circ_client_side(rendezvous_cookie);
- if (rend_circ == NULL) {
- log_warn(LD_REND, "Can't find any rendezvous circuit. Stopping");
- goto end;
- }
- assert_circ_anonymity_ok(rend_circ, get_options());
- /* It is possible to get a RENDEZVOUS2 cell before the INTRODUCE_ACK which
- * means that the circuit will be joined and already transmitting data. In
- * that case, simply skip the purpose change and close the intro circuit
- * like it should be. */
- if (TO_CIRCUIT(rend_circ)->purpose == CIRCUIT_PURPOSE_C_REND_JOINED) {
- goto end;
- }
- circuit_change_purpose(TO_CIRCUIT(rend_circ),
- CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED);
- /* Set timestamp_dirty, because circuit_expire_building expects it to
- * specify when a circuit entered the
- * CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED state. */
- TO_CIRCUIT(rend_circ)->timestamp_dirty = time(NULL);
- end:
- /* We don't need the intro circuit anymore. It did what it had to do! */
- circuit_change_purpose(TO_CIRCUIT(intro_circ),
- CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
- circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED);
- /* XXX: Close pending intro circuits we might have in parallel. */
- return;
- }
- /* Called when we get an INTRODUCE_ACK failure status code. Depending on our
- * failure cache status, either close the circuit or re-extend to a new
- * introduction point. */
- static void
- handle_introduce_ack_bad(origin_circuit_t *circ, int status)
- {
- tor_assert(circ);
- log_info(LD_REND, "Received INTRODUCE_ACK nack by %s. Reason: %u",
- safe_str_client(extend_info_describe(circ->build_state->chosen_exit)),
- status);
- /* It's a NAK. The introduction point didn't relay our request. */
- circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_INTRODUCING);
- /* Note down this failure in the intro point failure cache. Depending on how
- * many times we've tried this intro point, close it or reextend. */
- hs_cache_client_intro_state_note(&circ->hs_ident->identity_pk,
- &circ->hs_ident->intro_auth_pk,
- INTRO_POINT_FAILURE_GENERIC);
- }
- /* Called when we get an INTRODUCE_ACK on the intro circuit circ. The encoded
- * cell is in payload of length payload_len. Return 0 on success else a
- * negative value. The circuit is either close or reuse to re-extend to a new
- * introduction point. */
- static int
- handle_introduce_ack(origin_circuit_t *circ, const uint8_t *payload,
- size_t payload_len)
- {
- int status, ret = -1;
- tor_assert(circ);
- tor_assert(circ->build_state);
- tor_assert(circ->build_state->chosen_exit);
- assert_circ_anonymity_ok(circ, get_options());
- tor_assert(payload);
- status = hs_cell_parse_introduce_ack(payload, payload_len);
- switch (status) {
- case HS_CELL_INTRO_ACK_SUCCESS:
- ret = 0;
- handle_introduce_ack_success(circ);
- goto end;
- case HS_CELL_INTRO_ACK_FAILURE:
- case HS_CELL_INTRO_ACK_BADFMT:
- case HS_CELL_INTRO_ACK_NORELAY:
- handle_introduce_ack_bad(circ, status);
- /* We are going to see if we have to close the circuits (IP and RP) or we
- * can re-extend to a new intro point. */
- ret = close_or_reextend_intro_circ(circ);
- break;
- default:
- log_info(LD_PROTOCOL, "Unknown INTRODUCE_ACK status code %u from %s",
- status,
- safe_str_client(extend_info_describe(circ->build_state->chosen_exit)));
- break;
- }
- end:
- return ret;
- }
- /* Called when we get a RENDEZVOUS2 cell on the rendezvous circuit circ. The
- * encoded cell is in payload of length payload_len. Return 0 on success or a
- * negative value on error. On error, the circuit is marked for close. */
- STATIC int
- handle_rendezvous2(origin_circuit_t *circ, const uint8_t *payload,
- size_t payload_len)
- {
- int ret = -1;
- curve25519_public_key_t server_pk;
- uint8_t auth_mac[DIGEST256_LEN] = {0};
- uint8_t handshake_info[CURVE25519_PUBKEY_LEN + sizeof(auth_mac)] = {0};
- hs_ntor_rend_cell_keys_t keys;
- const hs_ident_circuit_t *ident;
- tor_assert(circ);
- tor_assert(payload);
- /* Make things easier. */
- ident = circ->hs_ident;
- tor_assert(ident);
- if (hs_cell_parse_rendezvous2(payload, payload_len, handshake_info,
- sizeof(handshake_info)) < 0) {
- goto err;
- }
- /* Get from the handshake info the SERVER_PK and AUTH_MAC. */
- memcpy(&server_pk, handshake_info, CURVE25519_PUBKEY_LEN);
- memcpy(auth_mac, handshake_info + CURVE25519_PUBKEY_LEN, sizeof(auth_mac));
- /* Generate the handshake info. */
- if (hs_ntor_client_get_rendezvous1_keys(&ident->intro_auth_pk,
- &ident->rendezvous_client_kp,
- &ident->intro_enc_pk, &server_pk,
- &keys) < 0) {
- log_info(LD_REND, "Unable to compute the rendezvous keys.");
- goto err;
- }
- /* Critical check, make sure that the MAC matches what we got with what we
- * computed just above. */
- if (!hs_ntor_client_rendezvous2_mac_is_good(&keys, auth_mac)) {
- log_info(LD_REND, "Invalid MAC in RENDEZVOUS2. Rejecting cell.");
- goto err;
- }
- /* Setup the e2e encryption on the circuit and finalize its state. */
- if (hs_circuit_setup_e2e_rend_circ(circ, keys.ntor_key_seed,
- sizeof(keys.ntor_key_seed), 0) < 0) {
- log_info(LD_REND, "Unable to setup the e2e encryption.");
- goto err;
- }
- /* Success. Hidden service connection finalized! */
- ret = 0;
- goto end;
- err:
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
- end:
- memwipe(&keys, 0, sizeof(keys));
- return ret;
- }
- /* Return true iff the client can fetch a descriptor for this service public
- * identity key and status_out if not NULL is untouched. If the client can
- * _not_ fetch the descriptor and if status_out is not NULL, it is set with
- * the fetch status code. */
- static unsigned int
- can_client_refetch_desc(const ed25519_public_key_t *identity_pk,
- hs_client_fetch_status_t *status_out)
- {
- hs_client_fetch_status_t status;
- tor_assert(identity_pk);
- /* Are we configured to fetch descriptors? */
- if (!get_options()->FetchHidServDescriptors) {
- log_warn(LD_REND, "We received an onion address for a hidden service "
- "descriptor but we are configured to not fetch.");
- status = HS_CLIENT_FETCH_NOT_ALLOWED;
- goto cannot;
- }
- /* Without a live consensus we can't do any client actions. It is needed to
- * compute the hashring for a service. */
- if (!networkstatus_get_live_consensus(approx_time())) {
- log_info(LD_REND, "Can't fetch descriptor for service %s because we "
- "are missing a live consensus. Stalling connection.",
- safe_str_client(ed25519_fmt(identity_pk)));
- status = HS_CLIENT_FETCH_MISSING_INFO;
- goto cannot;
- }
- if (!router_have_minimum_dir_info()) {
- log_info(LD_REND, "Can't fetch descriptor for service %s because we "
- "dont have enough descriptors. Stalling connection.",
- safe_str_client(ed25519_fmt(identity_pk)));
- status = HS_CLIENT_FETCH_MISSING_INFO;
- goto cannot;
- }
- /* Check if fetching a desc for this HS is useful to us right now */
- {
- const hs_descriptor_t *cached_desc = NULL;
- cached_desc = hs_cache_lookup_as_client(identity_pk);
- if (cached_desc && hs_client_any_intro_points_usable(identity_pk,
- cached_desc)) {
- log_info(LD_GENERAL, "We would fetch a v3 hidden service descriptor "
- "but we already have a usable descriptor.");
- status = HS_CLIENT_FETCH_HAVE_DESC;
- goto cannot;
- }
- }
- /* Don't try to refetch while we have a pending request for it. */
- if (directory_request_is_pending(identity_pk)) {
- log_info(LD_REND, "Already a pending directory request. Waiting on it.");
- status = HS_CLIENT_FETCH_PENDING;
- goto cannot;
- }
- /* Yes, client can fetch! */
- return 1;
- cannot:
- if (status_out) {
- *status_out = status;
- }
- return 0;
- }
- /* ========== */
- /* Public API */
- /* ========== */
- /** A circuit just finished connecting to a hidden service that the stream
- * <b>conn</b> has been waiting for. Let the HS subsystem know about this. */
- void
- hs_client_note_connection_attempt_succeeded(const edge_connection_t *conn)
- {
- tor_assert(connection_edge_is_rendezvous_stream(conn));
- if (BUG(conn->rend_data && conn->hs_ident)) {
- log_warn(LD_BUG, "Stream had both rend_data and hs_ident..."
- "Prioritizing hs_ident");
- }
- if (conn->hs_ident) { /* It's v3: pass it to the prop224 handler */
- note_connection_attempt_succeeded(conn->hs_ident);
- return;
- } else if (conn->rend_data) { /* It's v2: pass it to the legacy handler */
- rend_client_note_connection_attempt_ended(conn->rend_data);
- return;
- }
- }
- /* With the given encoded descriptor in desc_str and the service key in
- * service_identity_pk, decode the descriptor and set the desc pointer with a
- * newly allocated descriptor object.
- *
- * Return 0 on success else a negative value and desc is set to NULL. */
- int
- hs_client_decode_descriptor(const char *desc_str,
- const ed25519_public_key_t *service_identity_pk,
- hs_descriptor_t **desc)
- {
- int ret;
- uint8_t subcredential[DIGEST256_LEN];
- ed25519_public_key_t blinded_pubkey;
- tor_assert(desc_str);
- tor_assert(service_identity_pk);
- tor_assert(desc);
- /* Create subcredential for this HS so that we can decrypt */
- {
- uint64_t current_time_period = hs_get_time_period_num(0);
- hs_build_blinded_pubkey(service_identity_pk, NULL, 0, current_time_period,
- &blinded_pubkey);
- hs_get_subcredential(service_identity_pk, &blinded_pubkey, subcredential);
- }
- /* Parse descriptor */
- ret = hs_desc_decode_descriptor(desc_str, subcredential, desc);
- memwipe(subcredential, 0, sizeof(subcredential));
- if (ret < 0) {
- log_warn(LD_GENERAL, "Could not parse received descriptor as client.");
- if (get_options()->SafeLogging_ == SAFELOG_SCRUB_NONE) {
- log_warn(LD_GENERAL, "%s", escaped(desc_str));
- }
- goto err;
- }
- /* Make sure the descriptor signing key cross certifies with the computed
- * blinded key. Without this validation, anyone knowing the subcredential
- * and onion address can forge a descriptor. */
- tor_cert_t *cert = (*desc)->plaintext_data.signing_key_cert;
- if (tor_cert_checksig(cert,
- &blinded_pubkey, approx_time()) < 0) {
- log_warn(LD_GENERAL, "Descriptor signing key certificate signature "
- "doesn't validate with computed blinded key: %s",
- tor_cert_describe_signature_status(cert));
- goto err;
- }
- return 0;
- err:
- return -1;
- }
- /* Return true iff there are at least one usable intro point in the service
- * descriptor desc. */
- int
- hs_client_any_intro_points_usable(const ed25519_public_key_t *service_pk,
- const hs_descriptor_t *desc)
- {
- tor_assert(service_pk);
- tor_assert(desc);
- SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
- const hs_desc_intro_point_t *, ip) {
- if (intro_point_is_usable(service_pk, ip)) {
- goto usable;
- }
- } SMARTLIST_FOREACH_END(ip);
- return 0;
- usable:
- return 1;
- }
- /** Launch a connection to a hidden service directory to fetch a hidden
- * service descriptor using <b>identity_pk</b> to get the necessary keys.
- *
- * A hs_client_fetch_status_t code is returned. */
- int
- hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
- {
- hs_client_fetch_status_t status;
- tor_assert(identity_pk);
- if (!can_client_refetch_desc(identity_pk, &status)) {
- return status;
- }
- /* Try to fetch the desc and if we encounter an unrecoverable error, mark
- * the desc as unavailable for now. */
- status = fetch_v3_desc(identity_pk);
- if (fetch_status_should_close_socks(status)) {
- close_all_socks_conns_waiting_for_desc(identity_pk, status,
- END_STREAM_REASON_RESOLVEFAILED);
- /* Remove HSDir fetch attempts so that we can retry later if the user
- * wants us to regardless of if we closed any connections. */
- purge_hid_serv_request(identity_pk);
- }
- return status;
- }
- /* This is called when we are trying to attach an AP connection to these
- * hidden service circuits from connection_ap_handshake_attach_circuit().
- * Return 0 on success, -1 for a transient error that is actions were
- * triggered to recover or -2 for a permenent error where both circuits will
- * marked for close.
- *
- * The following supports every hidden service version. */
- int
- hs_client_send_introduce1(origin_circuit_t *intro_circ,
- origin_circuit_t *rend_circ)
- {
- return (intro_circ->hs_ident) ? send_introduce1(intro_circ, rend_circ) :
- rend_client_send_introduction(intro_circ,
- rend_circ);
- }
- /* Called when the client circuit circ has been established. It can be either
- * an introduction or rendezvous circuit. This function handles all hidden
- * service versions. */
- void
- hs_client_circuit_has_opened(origin_circuit_t *circ)
- {
- tor_assert(circ);
- /* Handle both version. v2 uses rend_data and v3 uses the hs circuit
- * identifier hs_ident. Can't be both. */
- switch (TO_CIRCUIT(circ)->purpose) {
- case CIRCUIT_PURPOSE_C_INTRODUCING:
- if (circ->hs_ident) {
- client_intro_circ_has_opened(circ);
- } else {
- rend_client_introcirc_has_opened(circ);
- }
- break;
- case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
- if (circ->hs_ident) {
- client_rendezvous_circ_has_opened(circ);
- } else {
- rend_client_rendcirc_has_opened(circ);
- }
- break;
- default:
- tor_assert_nonfatal_unreached();
- }
- }
- /* Called when we receive a RENDEZVOUS_ESTABLISHED cell. Change the state of
- * the circuit to CIRCUIT_PURPOSE_C_REND_READY. Return 0 on success else a
- * negative value and the circuit marked for close. */
- int
- hs_client_receive_rendezvous_acked(origin_circuit_t *circ,
- const uint8_t *payload, size_t payload_len)
- {
- tor_assert(circ);
- tor_assert(payload);
- (void) payload_len;
- if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND) {
- log_warn(LD_PROTOCOL, "Got a RENDEZVOUS_ESTABLISHED but we were not "
- "expecting one. Closing circuit.");
- goto err;
- }
- log_info(LD_REND, "Received an RENDEZVOUS_ESTABLISHED. This circuit is "
- "now ready for rendezvous.");
- circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_REND_READY);
- /* Set timestamp_dirty, because circuit_expire_building expects it to
- * specify when a circuit entered the _C_REND_READY state. */
- TO_CIRCUIT(circ)->timestamp_dirty = time(NULL);
- /* From a path bias point of view, this circuit is now successfully used.
- * Waiting any longer opens us up to attacks from malicious hidden services.
- * They could induce the client to attempt to connect to their hidden
- * service and never reply to the client's rend requests */
- pathbias_mark_use_success(circ);
- /* If we already have the introduction circuit built, make sure we send
- * the INTRODUCE cell _now_ */
- connection_ap_attach_pending(1);
- return 0;
- err:
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
- return -1;
- }
- /* This is called when a descriptor has arrived following a fetch request and
- * has been stored in the client cache. Every entry connection that matches
- * the service identity key in the ident will get attached to the hidden
- * service circuit. */
- void
- hs_client_desc_has_arrived(const hs_ident_dir_conn_t *ident)
- {
- time_t now = time(NULL);
- smartlist_t *conns = NULL;
- tor_assert(ident);
- conns = connection_list_by_type_state(CONN_TYPE_AP,
- AP_CONN_STATE_RENDDESC_WAIT);
- SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
- const hs_descriptor_t *desc;
- entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn);
- const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
- /* Only consider the entry connections that matches the service for which
- * we just fetched its descriptor. */
- if (!edge_conn->hs_ident ||
- !ed25519_pubkey_eq(&ident->identity_pk,
- &edge_conn->hs_ident->identity_pk)) {
- continue;
- }
- assert_connection_ok(base_conn, now);
- /* We were just called because we stored the descriptor for this service
- * so not finding a descriptor means we have a bigger problem. */
- desc = hs_cache_lookup_as_client(&ident->identity_pk);
- if (BUG(desc == NULL)) {
- goto end;
- }
- if (!hs_client_any_intro_points_usable(&ident->identity_pk, desc)) {
- log_info(LD_REND, "Hidden service descriptor is unusable. "
- "Closing streams.");
- connection_mark_unattached_ap(entry_conn,
- END_STREAM_REASON_RESOLVEFAILED);
- /* We are unable to use the descriptor so remove the directory request
- * from the cache so the next connection can try again. */
- note_connection_attempt_succeeded(edge_conn->hs_ident);
- goto end;
- }
- log_info(LD_REND, "Descriptor has arrived. Launching circuits.");
- /* Because the connection can now proceed to opening circuit and
- * ultimately connect to the service, reset those timestamp so the
- * connection is considered "fresh" and can continue without being closed
- * too early. */
- base_conn->timestamp_created = now;
- base_conn->timestamp_lastread = now;
- base_conn->timestamp_lastwritten = now;
- /* Change connection's state into waiting for a circuit. */
- base_conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
- connection_ap_mark_as_pending_circuit(entry_conn);
- } SMARTLIST_FOREACH_END(base_conn);
- end:
- /* We don't have ownership of the objects in this list. */
- smartlist_free(conns);
- }
- /* Return a newly allocated extend_info_t for a randomly chosen introduction
- * point for the given edge connection identifier ident. Return NULL if we
- * can't pick any usable introduction points. */
- extend_info_t *
- hs_client_get_random_intro_from_edge(const edge_connection_t *edge_conn)
- {
- tor_assert(edge_conn);
- return (edge_conn->hs_ident) ?
- client_get_random_intro(&edge_conn->hs_ident->identity_pk) :
- rend_client_get_random_intro(edge_conn->rend_data);
- }
- /* Called when get an INTRODUCE_ACK cell on the introduction circuit circ.
- * Return 0 on success else a negative value is returned. The circuit will be
- * closed or reuse to extend again to another intro point. */
- int
- hs_client_receive_introduce_ack(origin_circuit_t *circ,
- const uint8_t *payload, size_t payload_len)
- {
- int ret = -1;
- tor_assert(circ);
- tor_assert(payload);
- if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) {
- log_warn(LD_PROTOCOL, "Unexpected INTRODUCE_ACK on circuit %u.",
- (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
- goto end;
- }
- ret = (circ->hs_ident) ? handle_introduce_ack(circ, payload, payload_len) :
- rend_client_introduction_acked(circ, payload,
- payload_len);
- /* For path bias: This circuit was used successfully. NACK or ACK counts. */
- pathbias_mark_use_success(circ);
- end:
- return ret;
- }
- /* Called when get a RENDEZVOUS2 cell on the rendezvous circuit circ. Return
- * 0 on success else a negative value is returned. The circuit will be closed
- * on error. */
- int
- hs_client_receive_rendezvous2(origin_circuit_t *circ,
- const uint8_t *payload, size_t payload_len)
- {
- int ret = -1;
- tor_assert(circ);
- tor_assert(payload);
- /* Circuit can possibly be in both state because we could receive a
- * RENDEZVOUS2 cell before the INTRODUCE_ACK has been received. */
- if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY &&
- TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) {
- log_warn(LD_PROTOCOL, "Unexpected RENDEZVOUS2 cell on circuit %u. "
- "Closing circuit.",
- (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
- goto end;
- }
- log_info(LD_REND, "Got RENDEZVOUS2 cell from hidden service on circuit %u.",
- TO_CIRCUIT(circ)->n_circ_id);
- ret = (circ->hs_ident) ? handle_rendezvous2(circ, payload, payload_len) :
- rend_client_receive_rendezvous(circ, payload,
- payload_len);
- end:
- return ret;
- }
- /* Extend the introduction circuit circ to another valid introduction point
- * for the hidden service it is trying to connect to, or mark it and launch a
- * new circuit if we can't extend it. Return 0 on success or possible
- * success. Return -1 and mark the introduction circuit for close on permanent
- * failure.
- *
- * On failure, the caller is responsible for marking the associated rendezvous
- * circuit for close. */
- int
- hs_client_reextend_intro_circuit(origin_circuit_t *circ)
- {
- int ret = -1;
- extend_info_t *ei;
- tor_assert(circ);
- ei = (circ->hs_ident) ?
- client_get_random_intro(&circ->hs_ident->identity_pk) :
- rend_client_get_random_intro(circ->rend_data);
- if (ei == NULL) {
- log_warn(LD_REND, "No usable introduction points left. Closing.");
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
- goto end;
- }
- if (circ->remaining_relay_early_cells) {
- log_info(LD_REND, "Re-extending circ %u, this time to %s.",
- (unsigned int) TO_CIRCUIT(circ)->n_circ_id,
- safe_str_client(extend_info_describe(ei)));
- ret = circuit_extend_to_new_exit(circ, ei);
- if (ret == 0) {
- /* We were able to extend so update the timestamp so we avoid expiring
- * this circuit too early. The intro circuit is short live so the
- * linkability issue is minimized, we just need the circuit to hold a
- * bit longer so we can introduce. */
- TO_CIRCUIT(circ)->timestamp_dirty = time(NULL);
- }
- } else {
- log_info(LD_REND, "Closing intro circ %u (out of RELAY_EARLY cells).",
- (unsigned int) TO_CIRCUIT(circ)->n_circ_id);
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
- /* connection_ap_handshake_attach_circuit will launch a new intro circ. */
- ret = 0;
- }
- end:
- extend_info_free(ei);
- return ret;
- }
- /* Release all the storage held by the client subsystem. */
- void
- hs_client_free_all(void)
- {
- /* Purge the hidden service request cache. */
- hs_purge_last_hid_serv_requests();
- }
- /* Purge all potentially remotely-detectable state held in the hidden
- * service client code. Called on SIGNAL NEWNYM. */
- void
- hs_client_purge_state(void)
- {
- /* v2 subsystem. */
- rend_client_purge_state();
- /* Cancel all descriptor fetches. Do this first so once done we are sure
- * that our descriptor cache won't modified. */
- cancel_descriptor_fetches();
- /* Purge the introduction point state cache. */
- hs_cache_client_intro_state_purge();
- /* Purge the descriptor cache. */
- hs_cache_purge_as_client();
- /* Purge the last hidden service request cache. */
- hs_purge_last_hid_serv_requests();
- log_info(LD_REND, "Hidden service client state has been purged.");
- }
- /* Called when our directory information has changed. */
- void
- hs_client_dir_info_changed(void)
- {
- /* We have possibly reached the minimum directory information or new
- * consensus so retry all pending SOCKS connection in
- * AP_CONN_STATE_RENDDESC_WAIT state in order to fetch the descriptor. */
- retry_all_socks_conn_waiting_for_desc();
- }
|