123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244 |
- /* 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
- **/
- #include "or.h"
- #include "hs_circuit.h"
- #include "hs_ident.h"
- #include "connection_edge.h"
- #include "rendclient.h"
- #include "hs_descriptor.h"
- #include "hs_cache.h"
- #include "config.h"
- #include "directory.h"
- #include "hs_client.h"
- #include "router.h"
- /* 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)
- {
- (void) hs_conn_ident;
- /* TODO: When implementing client side */
- return;
- }
- /* 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 1 on
- * success or -1 on error. */
- static int
- 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(approx_time());
- 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 -1;
- }
- /* Copy onion pk to a dir_ident so that we attach it to the dir conn */
- ed25519_pubkey_copy(&hs_conn_dir_ident.identity_pk, onion_identity_pk);
- /* 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_upload_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)));
- /* 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 1;
- }
- /** 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(approx_time());
- 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, 1 is returned. If no hidden service is left to ask, return 0.
- * On error, -1 is returned. */
- static int
- 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 0;
- }
- return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs);
- }
- /** 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];
- tor_assert(desc_str);
- tor_assert(service_identity_pk);
- tor_assert(desc);
- /* Create subcredential for this HS so that we can decrypt */
- {
- ed25519_public_key_t blinded_pubkey;
- uint64_t current_time_period = hs_get_time_period_num(approx_time());
- 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");
- goto err;
- }
- return 0;
- err:
- return -1;
- }
- /** Return true if there are any usable intro points in the v3 HS descriptor
- * <b>desc</b>. */
- int
- hs_client_any_intro_points_usable(const hs_descriptor_t *desc)
- {
- /* XXX stub waiting for more client-side work:
- equivalent to v2 rend_client_any_intro_points_usable() */
- tor_assert(desc);
- 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.
- *
- * On success, 1 is returned. If no hidden service is left to ask, return 0.
- * On error, -1 is returned. (retval is only used by unittests right now) */
- int
- hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
- {
- 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.");
- return 0;
- }
- /* 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(cached_desc)) {
- log_warn(LD_GENERAL, "We would fetch a v3 hidden service descriptor "
- "but we already have a useable descriprot.");
- return 0;
- }
- }
- return fetch_v3_desc(identity_pk);
- }
|