diff options
Diffstat (limited to 'src/or/hs_service.c')
| -rw-r--r-- | src/or/hs_service.c | 960 |
1 files changed, 911 insertions, 49 deletions
diff --git a/src/or/hs_service.c b/src/or/hs_service.c index 9114655edf..3cde2fe1b1 100644 --- a/src/or/hs_service.c +++ b/src/or/hs_service.c @@ -10,6 +10,7 @@ #include "or.h" #include "circpathbias.h" +#include "circuitbuild.h" #include "circuitlist.h" #include "config.h" #include "networkstatus.h" @@ -18,12 +19,18 @@ #include "rendservice.h" #include "router.h" #include "routerkeys.h" +#include "routerlist.h" #include "hs_common.h" #include "hs_config.h" +#include "hs_circuit.h" +#include "hs_descriptor.h" +#include "hs_ident.h" #include "hs_intropoint.h" #include "hs_service.h" +/* Trunnel */ +#include "ed25519_cert.h" #include "hs/cell_establish_intro.h" #include "hs/cell_common.h" @@ -36,6 +43,19 @@ var = *var##_iter; #define FOR_EACH_SERVICE_END } STMT_END ; +/* Helper macro. Iterate over both current and previous descriptor of a + * service. The var is the name of the descriptor pointer. This macro skips + * any descriptor object of the service that is NULL. */ +#define FOR_EACH_DESCRIPTOR_BEGIN(service, var) \ + STMT_BEGIN \ + hs_service_descriptor_t *var; \ + for (int var ## _loop_idx = 0; var ## _loop_idx < 2; \ + ++var ## _loop_idx) { \ + (var ## _loop_idx == 0) ? (var = service->desc_current) : \ + (var = service->desc_next); \ + if (var == NULL) continue; +#define FOR_EACH_DESCRIPTOR_END } STMT_END ; + /* Onion service directory file names. */ static const char *fname_keyfile_prefix = "hs_ed25519"; static const char *fname_hostname = "hostname"; @@ -213,13 +233,209 @@ service_free_all(void) } } +/* Free a given service intro point object. */ +static void +service_intro_point_free(hs_service_intro_point_t *ip) +{ + if (!ip) { + return; + } + memwipe(&ip->auth_key_kp, 0, sizeof(ip->auth_key_kp)); + memwipe(&ip->enc_key_kp, 0, sizeof(ip->enc_key_kp)); + crypto_pk_free(ip->legacy_key); + replaycache_free(ip->replay_cache); + hs_intro_free_content(&ip->base); + tor_free(ip); +} + +/* Helper: free an hs_service_intro_point_t object. This function is used by + * digest256map_free() which requires a void * pointer. */ +static void +service_intro_point_free_(void *obj) +{ + service_intro_point_free(obj); +} + +/* Return a newly allocated service intro point and fully initialized from the + * given extend_info_t ei if non NULL. If is_legacy is true, we also generate + * the legacy key. On error, NULL is returned. */ +static hs_service_intro_point_t * +service_intro_point_new(const extend_info_t *ei, unsigned int is_legacy) +{ + hs_desc_link_specifier_t *ls; + hs_service_intro_point_t *ip; + + ip = tor_malloc_zero(sizeof(*ip)); + /* We'll create the key material. No need for extra strong, those are short + * term keys. */ + ed25519_keypair_generate(&ip->auth_key_kp, 0); + + /* XXX: These will be controlled by consensus params. (#20961) */ + ip->introduce2_max = + crypto_rand_int_range(INTRO_POINT_MIN_LIFETIME_INTRODUCTIONS, + INTRO_POINT_MAX_LIFETIME_INTRODUCTIONS); + ip->time_to_expire = time(NULL) + + crypto_rand_int_range(INTRO_POINT_LIFETIME_MIN_SECONDS, + INTRO_POINT_LIFETIME_MAX_SECONDS); + ip->replay_cache = replaycache_new(0, 0); + + /* Initialize the base object. We don't need the certificate object. */ + ip->base.link_specifiers = smartlist_new(); + + /* Generate the encryption key for this intro point. */ + curve25519_keypair_generate(&ip->enc_key_kp, 0); + /* Figure out if this chosen node supports v3 or is legacy only. */ + if (is_legacy) { + ip->base.is_only_legacy = 1; + /* Legacy mode that is doesn't support v3+ with ed25519 auth key. */ + ip->legacy_key = crypto_pk_new(); + if (crypto_pk_generate_key(ip->legacy_key) < 0) { + goto err; + } + } + + if (ei == NULL) { + goto done; + } + + /* We'll try to add all link specifier. Legacy, IPv4 and ed25519 are + * mandatory. */ + ls = hs_desc_link_specifier_new(ei, LS_IPV4); + /* It is impossible to have an extend info object without a v4. */ + tor_assert(ls); + smartlist_add(ip->base.link_specifiers, ls); + ls = hs_desc_link_specifier_new(ei, LS_LEGACY_ID); + /* It is impossible to have an extend info object without an identity + * digest. */ + tor_assert(ls); + smartlist_add(ip->base.link_specifiers, ls); + ls = hs_desc_link_specifier_new(ei, LS_ED25519_ID); + /* It is impossible to have an extend info object without an ed25519 + * identity key. */ + tor_assert(ls); + smartlist_add(ip->base.link_specifiers, ls); + /* IPv6 is optional. */ + ls = hs_desc_link_specifier_new(ei, LS_IPV6); + if (ls) { + smartlist_add(ip->base.link_specifiers, ls); + } + + /* Finally, copy onion key from the extend_info_t object. */ + memcpy(&ip->onion_key, &ei->curve25519_onion_key, sizeof(ip->onion_key)); + + done: + return ip; + err: + service_intro_point_free(ip); + return NULL; +} + +/* Add the given intro point object to the given intro point map. The intro + * point MUST have its RSA encryption key set if this is a legacy type or the + * authentication key set otherwise. */ +static void +service_intro_point_add(digest256map_t *map, hs_service_intro_point_t *ip) +{ + uint8_t key[DIGEST256_LEN] = {0}; + + tor_assert(map); + tor_assert(ip); + + memcpy(key, ip->auth_key_kp.pubkey.pubkey, sizeof(key)); + digest256map_set(map, key, ip); +} + +/* From a given intro point, return the first link specifier of type + * encountered in the link specifier list. Return NULL if it can't be found. + * + * The caller does NOT have ownership of the object, the intro point does. */ +static hs_desc_link_specifier_t * +get_link_spec_by_type(const hs_service_intro_point_t *ip, uint8_t type) +{ + hs_desc_link_specifier_t *lnk_spec = NULL; + + tor_assert(ip); + + SMARTLIST_FOREACH_BEGIN(ip->base.link_specifiers, + hs_desc_link_specifier_t *, ls) { + if (ls->type == type) { + lnk_spec = ls; + goto end; + } + } SMARTLIST_FOREACH_END(ls); + + end: + return lnk_spec; +} + +/* Given a service intro point, return the node_t associated to it. This can + * return NULL if the given intro point has no legacy ID or if the node can't + * be found in the consensus. */ +static const node_t * +get_node_from_intro_point(const hs_service_intro_point_t *ip) +{ + const hs_desc_link_specifier_t *ls; + + tor_assert(ip); + + ls = get_link_spec_by_type(ip, LS_LEGACY_ID); + /* Legacy ID is mandatory for an intro point object to have. */ + tor_assert(ls); + /* XXX In the future, we want to only use the ed25519 ID (#22173). */ + return node_get_by_id((const char *) ls->u.legacy_id); +} + +/* Return an introduction point circuit matching the given intro point object. + * NULL is returned is no such circuit can be found. */ +static origin_circuit_t * +get_intro_circuit(const hs_service_intro_point_t *ip) +{ + origin_circuit_t *circ = NULL; + + tor_assert(ip); + + if (ip->base.is_only_legacy) { + uint8_t digest[DIGEST_LEN]; + if (BUG(crypto_pk_get_digest(ip->legacy_key, (char *) digest) < 0)) { + goto end; + } + circ = hs_circuitmap_get_intro_circ_v2_service_side(digest); + } else { + circ = hs_circuitmap_get_intro_circ_v3_service_side( + &ip->auth_key_kp.pubkey); + } + end: + return circ; +} + /* Close all rendezvous circuits for the given service. */ static void close_service_rp_circuits(hs_service_t *service) { + origin_circuit_t *ocirc = NULL; + tor_assert(service); - /* XXX: To implement. */ - return; + + /* The reason we go over all circuit instead of using the circuitmap API is + * because most hidden service circuits are rendezvous circuits so there is + * no real improvement at getting all rendezvous circuits from the + * circuitmap and then going over them all to find the right ones. + * Furthermore, another option would have been to keep a list of RP cookies + * for a service but it creates an engineering complexity since we don't + * have a "RP circuit closed" event to clean it up properly so we avoid a + * memory DoS possibility. */ + + while ((ocirc = circuit_get_next_service_rp_circ(ocirc))) { + /* Only close circuits that are v3 and for this service. */ + if (ocirc->hs_ident != NULL && + ed25519_pubkey_eq(ô->hs_ident->identity_pk, + &service->keys.identity_pk)) { + /* Reason is FINISHED because service has been removed and thus the + * circuit is considered old/uneeded. When freed, it is removed from the + * hs circuitmap. */ + circuit_mark_for_close(TO_CIRCUIT(ocirc), END_CIRC_REASON_FINISHED); + } + } } /* Close the circuit(s) for the given map of introduction points. */ @@ -230,13 +446,11 @@ close_intro_circuits(hs_service_intropoints_t *intro_points) DIGEST256MAP_FOREACH(intro_points->map, key, const hs_service_intro_point_t *, ip) { - origin_circuit_t *ocirc = - hs_circuitmap_get_intro_circ_v3_service_side( - &ip->auth_key_kp.pubkey); + origin_circuit_t *ocirc = get_intro_circuit(ip); if (ocirc) { - hs_circuitmap_remove_circuit(TO_CIRCUIT(ocirc)); /* Reason is FINISHED because service has been removed and thus the - * circuit is considered old/uneeded. */ + * circuit is considered old/uneeded. When freed, the circuit is removed + * from the HS circuitmap. */ circuit_mark_for_close(TO_CIRCUIT(ocirc), END_CIRC_REASON_FINISHED); } } DIGEST256MAP_FOREACH_END; @@ -248,12 +462,9 @@ close_service_intro_circuits(hs_service_t *service) { tor_assert(service); - if (service->desc_current) { - close_intro_circuits(&service->desc_current->intro_points); - } - if (service->desc_next) { - close_intro_circuits(&service->desc_next->intro_points); - } + FOR_EACH_DESCRIPTOR_BEGIN(service, desc) { + close_intro_circuits(&desc->intro_points); + } FOR_EACH_DESCRIPTOR_END; } /* Close any circuits related to the given service. */ @@ -281,7 +492,7 @@ move_descriptor_intro_points(hs_service_descriptor_t *src, tor_assert(src); tor_assert(dst); - /* XXX: Free dst introduction points. */ + digest256map_free(dst->intro_points.map, service_intro_point_free_); dst->intro_points.map = src->intro_points.map; /* Nullify the source. */ src->intro_points.map = NULL; @@ -295,7 +506,6 @@ move_intro_points(hs_service_t *src, hs_service_t *dst) tor_assert(src); tor_assert(dst); - /* Cleanup destination. */ if (src->desc_current && dst->desc_current) { move_descriptor_intro_points(src->desc_current, dst->desc_current); } @@ -351,7 +561,6 @@ static void register_all_services(void) { struct hs_service_ht *new_service_map; - hs_service_t *s, **iter; tor_assert(hs_service_staging_list); @@ -371,6 +580,8 @@ register_all_services(void) move_ephemeral_services(hs_service_map, new_service_map); SMARTLIST_FOREACH_BEGIN(hs_service_staging_list, hs_service_t *, snew) { + hs_service_t *s; + /* Check if that service is already in our global map and if so, we'll * transfer the intro points to it. */ s = find_service(hs_service_map, &snew->keys.identity_pk); @@ -398,9 +609,9 @@ register_all_services(void) /* Close any circuits associated with the non surviving services. Every * service in the current global map are roaming. */ - HT_FOREACH(iter, hs_service_ht, hs_service_map) { - close_service_circuits(*iter); - } + FOR_EACH_SERVICE_BEGIN(service) { + close_service_circuits(service); + } FOR_EACH_SERVICE_END; /* Time to make the switch. We'll clear the staging list because its content * has now changed ownership to the map. */ @@ -522,13 +733,673 @@ load_service_keys(hs_service_t *service) return ret; } +/* Free a given service descriptor object and all key material is wiped. */ +static void +service_descriptor_free(hs_service_descriptor_t *desc) +{ + if (!desc) { + return; + } + hs_descriptor_free(desc->desc); + memwipe(&desc->signing_kp, 0, sizeof(desc->signing_kp)); + memwipe(&desc->blinded_kp, 0, sizeof(desc->blinded_kp)); + /* Cleanup all intro points. */ + digest256map_free(desc->intro_points.map, service_intro_point_free_); + tor_free(desc); +} + +/* Return a newly allocated service descriptor object. */ +static hs_service_descriptor_t * +service_descriptor_new(void) +{ + hs_service_descriptor_t *sdesc = tor_malloc_zero(sizeof(*sdesc)); + sdesc->desc = tor_malloc_zero(sizeof(hs_descriptor_t)); + /* Initialize the intro points map. */ + sdesc->intro_points.map = digest256map_new(); + return sdesc; +} + +#if 0 +/* Copy the descriptor link specifier object from src to dst. */ +static void +link_specifier_copy(hs_desc_link_specifier_t *dst, + const hs_desc_link_specifier_t *src) +{ + tor_assert(dst); + tor_assert(src); + memcpy(dst, src, sizeof(hs_desc_link_specifier_t)); +} + +/* Using a given descriptor signing keypair signing_kp, a service intro point + * object ip and the time now, setup the content of an already allocated + * descriptor intro desc_ip. + * + * Return 0 on success else a negative value. */ +static int +setup_desc_intro_point(const ed25519_keypair_t *signing_kp, + const hs_service_intro_point_t *ip, + time_t now, hs_desc_intro_point_t *desc_ip) +{ + int ret = -1; + time_t nearest_hour = now - (now % 3600); + + tor_assert(signing_kp); + tor_assert(ip); + tor_assert(desc_ip); + + /* Copy the onion key. */ + memcpy(&desc_ip->onion_key, &ip->onion_key, sizeof(desc_ip->onion_key)); + + /* Key and certificate material. */ + desc_ip->auth_key_cert = tor_cert_create(signing_kp, + CERT_TYPE_AUTH_HS_IP_KEY, + &ip->auth_key_kp.pubkey, + nearest_hour, + HS_DESC_CERT_LIFETIME, + CERT_FLAG_INCLUDE_SIGNING_KEY); + if (desc_ip->auth_key_cert == NULL) { + log_warn(LD_REND, "Unable to create intro point auth-key certificate"); + goto done; + } + + /* Copy link specifier(s). */ + SMARTLIST_FOREACH_BEGIN(ip->base.link_specifiers, + const hs_desc_link_specifier_t *, ls) { + hs_desc_link_specifier_t *dup = tor_malloc_zero(sizeof(*dup)); + link_specifier_copy(dup, ls); + smartlist_add(desc_ip->link_specifiers, dup); + } SMARTLIST_FOREACH_END(ls); + + /* For a legacy intro point, we'll use an RSA/ed cross certificate. */ + if (ip->base.is_only_legacy) { + desc_ip->legacy.key = crypto_pk_dup_key(ip->legacy_key); + /* Create cross certification cert. */ + ssize_t cert_len = tor_make_rsa_ed25519_crosscert( + &signing_kp->pubkey, + desc_ip->legacy.key, + nearest_hour + HS_DESC_CERT_LIFETIME, + &desc_ip->legacy.cert.encoded); + if (cert_len < 0) { + log_warn(LD_REND, "Unable to create enc key legacy cross cert."); + goto done; + } + desc_ip->legacy.cert.len = cert_len; + } + + /* Encryption key and its cross certificate. */ + { + ed25519_public_key_t ed25519_pubkey; + + /* Use the public curve25519 key. */ + memcpy(&desc_ip->enc_key, &ip->enc_key_kp.pubkey, + sizeof(desc_ip->enc_key)); + /* The following can't fail. */ + ed25519_public_key_from_curve25519_public_key(&ed25519_pubkey, + &ip->enc_key_kp.pubkey, + 0); + desc_ip->enc_key_cert = tor_cert_create(signing_kp, + CERT_TYPE_CROSS_HS_IP_KEYS, + &ed25519_pubkey, nearest_hour, + HS_DESC_CERT_LIFETIME, + CERT_FLAG_INCLUDE_SIGNING_KEY); + if (desc_ip->enc_key_cert == NULL) { + log_warn(LD_REND, "Unable to create enc key curve25519 cross cert."); + goto done; + } + } + /* Success. */ + ret = 0; + + done: + return ret; +} + +/* Using the given descriptor from the given service, build the descriptor + * intro point list so we can then encode the descriptor for publication. This + * function does not pick intro points, they have to be in the descriptor + * current map. Cryptographic material (keys) must be initialized in the + * descriptor for this function to make sense. */ +static void +build_desc_intro_points(const hs_service_t *service, + hs_service_descriptor_t *desc, time_t now) +{ + hs_desc_encrypted_data_t *encrypted; + + tor_assert(service); + tor_assert(desc); + + /* Ease our life. */ + encrypted = &desc->desc->encrypted_data; + /* Cleanup intro points, we are about to set them from scratch. */ + hs_descriptor_free_intro_points(desc->desc); + + DIGEST256MAP_FOREACH(desc->intro_points.map, key, + const hs_service_intro_point_t *, ip) { + hs_desc_intro_point_t *desc_ip = hs_desc_intro_point_new(); + if (setup_desc_intro_point(&desc->signing_kp, ip, now, desc_ip) < 0) { + hs_desc_intro_point_free(desc_ip); + continue; + } + /* We have a valid descriptor intro point. Add it to the list. */ + smartlist_add(encrypted->intro_points, desc_ip); + } DIGEST256MAP_FOREACH_END; +} + +#endif /* build_desc_intro_points is disabled because not used */ + +/* Populate the descriptor encrypted section fomr the given service object. + * This will generate a valid list of introduction points that can be used + * after for circuit creation. Return 0 on success else -1 on error. */ +static int +build_service_desc_encrypted(const hs_service_t *service, + hs_service_descriptor_t *desc) +{ + hs_desc_encrypted_data_t *encrypted; + + tor_assert(service); + tor_assert(desc); + + encrypted = &desc->desc->encrypted_data; + + encrypted->create2_ntor = 1; + encrypted->single_onion_service = service->config.is_single_onion; + + /* Setup introduction points from what we have in the service. */ + if (encrypted->intro_points == NULL) { + encrypted->intro_points = smartlist_new(); + } + /* We do NOT build introduction point yet, we only do that once the circuit + * have been opened. Until we have the right number of introduction points, + * we do not encode anything in the descriptor. */ + + /* XXX: Support client authorization (#20700). */ + encrypted->intro_auth_types = NULL; + return 0; +} + +/* Populare the descriptor plaintext section from the given service object. + * The caller must make sure that the keys in the descriptors are valid that + * is are non-zero. Return 0 on success else -1 on error. */ +static int +build_service_desc_plaintext(const hs_service_t *service, + hs_service_descriptor_t *desc, time_t now) +{ + int ret = -1; + hs_desc_plaintext_data_t *plaintext; + + tor_assert(service); + tor_assert(desc); + /* XXX: Use a "assert_desc_ok()" ? */ + tor_assert(!tor_mem_is_zero((char *) &desc->blinded_kp, + sizeof(desc->blinded_kp))); + tor_assert(!tor_mem_is_zero((char *) &desc->signing_kp, + sizeof(desc->signing_kp))); + + /* Set the subcredential. */ + hs_get_subcredential(&service->keys.identity_pk, &desc->blinded_kp.pubkey, + desc->desc->subcredential); + + plaintext = &desc->desc->plaintext_data; + + plaintext->version = service->config.version; + plaintext->lifetime_sec = HS_DESC_DEFAULT_LIFETIME; + plaintext->signing_key_cert = + tor_cert_create(&desc->blinded_kp, CERT_TYPE_SIGNING_HS_DESC, + &desc->signing_kp.pubkey, now, HS_DESC_CERT_LIFETIME, + CERT_FLAG_INCLUDE_SIGNING_KEY); + if (plaintext->signing_key_cert == NULL) { + log_warn(LD_REND, "Unable to create descriptor signing certificate for " + "service %s", + safe_str_client(service->onion_address)); + goto end; + } + /* Copy public key material to go in the descriptor. */ + ed25519_pubkey_copy(&plaintext->signing_pubkey, &desc->signing_kp.pubkey); + ed25519_pubkey_copy(&plaintext->blinded_pubkey, &desc->blinded_kp.pubkey); + /* Success. */ + ret = 0; + + end: + return ret; +} + +/* For the given service and descriptor object, create the key material which + * is the blinded keypair and the descriptor signing keypair. Return 0 on + * success else -1 on error where the generated keys MUST be ignored. */ +static int +build_service_desc_keys(const hs_service_t *service, + hs_service_descriptor_t *desc, + uint64_t time_period_num) +{ + int ret = 0; + ed25519_keypair_t kp; + + tor_assert(desc); + tor_assert(!tor_mem_is_zero((char *) &service->keys.identity_pk, + ED25519_PUBKEY_LEN)); + + /* XXX: Support offline key feature (#18098). */ + + /* Copy the identity keys to the keypair so we can use it to create the + * blinded key. */ + memcpy(&kp.pubkey, &service->keys.identity_pk, sizeof(kp.pubkey)); + memcpy(&kp.seckey, &service->keys.identity_sk, sizeof(kp.seckey)); + /* Build blinded keypair for this time period. */ + hs_build_blinded_keypair(&kp, NULL, 0, time_period_num, &desc->blinded_kp); + /* Let's not keep too much traces of our keys in memory. */ + memwipe(&kp, 0, sizeof(kp)); + + /* No need for extra strong, this is a temporary key only for this + * descriptor. Nothing long term. */ + if (ed25519_keypair_generate(&desc->signing_kp, 0) < 0) { + log_warn(LD_REND, "Can't generate descriptor signing keypair for " + "service %s", + safe_str_client(service->onion_address)); + ret = -1; + } + + return ret; +} + +/* Given a service and the current time, build a descriptor for the service. + * This function does not pick introduction point, this needs to be done by + * the update function. On success, desc_out will point to the newly allocated + * descriptor object. + * + * This can error if we are unable to create keys or certificate. */ +static void +build_service_descriptor(hs_service_t *service, time_t now, + uint64_t time_period_num, + hs_service_descriptor_t **desc_out) +{ + char *encoded_desc; + hs_service_descriptor_t *desc; + + tor_assert(service); + tor_assert(desc_out); + + desc = service_descriptor_new(); + + /* Create the needed keys so we can setup the descriptor content. */ + if (build_service_desc_keys(service, desc, time_period_num) < 0) { + goto err; + } + /* Setup plaintext descriptor content. */ + if (build_service_desc_plaintext(service, desc, now) < 0) { + goto err; + } + /* Setup encrypted descriptor content. */ + if (build_service_desc_encrypted(service, desc) < 0) { + goto err; + } + + /* Let's make sure that we've created a descriptor that can actually be + * encoded properly. This function also checks if the encoded output is + * decodable after. */ + if (BUG(hs_desc_encode_descriptor(desc->desc, &desc->signing_kp, + &encoded_desc) < 0)) { + goto err; + } + tor_free(encoded_desc); + + /* Assign newly built descriptor to the next slot. */ + *desc_out = desc; + return; + + err: + service_descriptor_free(desc); +} + +/* Build descriptors for each service if needed. There are conditions to build + * a descriptor which are details in the function. */ +static void +build_all_descriptors(time_t now) +{ + FOR_EACH_SERVICE_BEGIN(service) { + if (service->desc_current == NULL) { + /* This means we just booted up because else this descriptor will never + * be NULL as it should always point to the descriptor that was in + * desc_next after rotation. */ + build_service_descriptor(service, now, hs_get_time_period_num(now), + &service->desc_current); + + log_info(LD_REND, "Hidden service %s current descriptor successfully " + "built. Now scheduled for upload.", + safe_str_client(service->onion_address)); + } + /* A next descriptor to NULL indicate that we need to build a fresh one if + * we are in the overlap period for the _next_ time period since it means + * we either just booted or we just rotated our descriptors. */ + if (hs_overlap_mode_is_active(NULL, now) && service->desc_next == NULL) { + build_service_descriptor(service, now, hs_get_next_time_period_num(now), + &service->desc_next); + log_info(LD_REND, "Hidden service %s next descriptor successfully " + "built. Now scheduled for upload.", + safe_str_client(service->onion_address)); + } + } FOR_EACH_DESCRIPTOR_END; +} + +/* Randomly pick a node to become an introduction point but not present in the + * given exclude_nodes list. The chosen node is put in the exclude list + * regardless of success or not because in case of failure, the node is simply + * unsusable from that point on. If direct_conn is set, try to pick a node + * that our local firewall/policy allows to directly connect to and if not, + * fallback to a normal 3-hop node. Return a newly allocated service intro + * point ready to be used for encoding. NULL on error. */ +static hs_service_intro_point_t * +pick_intro_point(unsigned int direct_conn, smartlist_t *exclude_nodes) +{ + const node_t *node; + extend_info_t *info = NULL; + hs_service_intro_point_t *ip = NULL; + /* Normal 3-hop introduction point flags. */ + router_crn_flags_t flags = CRN_NEED_UPTIME | CRN_NEED_DESC; + /* Single onion flags. */ + router_crn_flags_t direct_flags = flags | CRN_PREF_ADDR | CRN_DIRECT_CONN; + + node = router_choose_random_node(exclude_nodes, get_options()->ExcludeNodes, + direct_conn ? direct_flags : flags); + if (node == NULL && direct_conn) { + /* Unable to find a node for direct connection, let's fall back to a + * normal 3-hop node. */ + node = router_choose_random_node(exclude_nodes, + get_options()->ExcludeNodes, flags); + } + if (!node) { + goto err; + } + + /* We have a suitable node, add it to the exclude list. We do this *before* + * we can validate the extend information because even in case of failure, + * we don't want to use that node anymore. */ + smartlist_add(exclude_nodes, (void *) node); + + /* We do this to ease our life but also this call makes appropriate checks + * of the node object such as validating ntor support for instance. */ + info = extend_info_from_node(node, direct_conn); + if (BUG(info == NULL)) { + goto err; + } + /* Create our objects and populate them with the node information. */ + ip = service_intro_point_new(info, !node_supports_ed25519_hs_intro(node)); + if (ip == NULL) { + goto err; + } + extend_info_free(info); + return ip; + err: + service_intro_point_free(ip); + extend_info_free(info); + return NULL; +} + +/* For a given descriptor from the given service, pick any needed intro points + * and update the current map with those newly picked intro points. Return the + * number node that might have been added to the descriptor current map. */ +static unsigned int +pick_needed_intro_points(hs_service_t *service, + hs_service_descriptor_t *desc) +{ + int i = 0, num_needed_ip; + smartlist_t *exclude_nodes = smartlist_new(); + + tor_assert(service); + tor_assert(desc); + + /* Compute how many intro points we actually need to open. */ + num_needed_ip = service->config.num_intro_points - + digest256map_size(desc->intro_points.map); + if (BUG(num_needed_ip < 0)) { + /* Let's not make tor freak out here and just skip this. */ + goto done; + } + /* We want to end up with config.num_intro_points intro points, but if we + * have no intro points at all (chances are they all cycled or we are + * starting up), we launch NUM_INTRO_POINTS_EXTRA extra circuits and use the + * first config.num_intro_points that complete. See proposal #155, section 4 + * for the rationale of this which is purely for performance. + * + * The ones after the first config.num_intro_points will be converted to + * 'General' internal circuits and then we'll drop them from the list of + * intro points. */ + if (digest256map_size(desc->intro_points.map) == 0) { + /* XXX: Should a consensus param control that value? */ + num_needed_ip += NUM_INTRO_POINTS_EXTRA; + } + + /* Build an exclude list of nodes of our intro point(s). The expiring intro + * points are OK to pick again because this is afterall a concept of round + * robin so they are considered valid nodes to pick again. */ + DIGEST256MAP_FOREACH(desc->intro_points.map, key, + hs_service_intro_point_t *, ip) { + smartlist_add(exclude_nodes, (void *) get_node_from_intro_point(ip)); + } DIGEST256MAP_FOREACH_END; + + for (i = 0; i < num_needed_ip; i++) { + hs_service_intro_point_t *ip; + + /* This function will add the picked intro point node to the exclude nodes + * list so we don't pick the same one at the next iteration. */ + ip = pick_intro_point(service->config.is_single_onion, exclude_nodes); + if (ip == NULL) { + /* If we end up unable to pick an introduction point it is because we + * can't find suitable node and calling this again is highly unlikely to + * give us a valid node all of the sudden. */ + log_info(LD_REND, "Unable to find a suitable node to be an " + "introduction point for service %s.", + safe_str_client(service->onion_address)); + goto done; + } + /* Valid intro point object, add it to the descriptor current map. */ + service_intro_point_add(desc->intro_points.map, ip); + } + + /* Success. */ + done: + /* We don't have ownership of the node_t object in this list. */ + smartlist_free(exclude_nodes); + return i; +} + +/* Update the given descriptor from the given service. The possible update + * actions includes: + * - Picking missing intro points if needed. + * - Incrementing the revision counter if needed. + */ +static void +update_service_descriptor(hs_service_t *service, + hs_service_descriptor_t *desc, time_t now) +{ + unsigned int num_intro_points; + + tor_assert(service); + tor_assert(desc); + tor_assert(desc->desc); + + num_intro_points = digest256map_size(desc->intro_points.map); + + /* Pick any missing introduction point(s). */ + if (num_intro_points < service->config.num_intro_points) { + unsigned int num_new_intro_points = pick_needed_intro_points(service, + desc); + if (num_new_intro_points != 0) { + log_info(LD_REND, "Service %s just picked %u intro points and wanted " + "%u. It currently has %d intro points. " + "Launching ESTABLISH_INTRO circuit shortly.", + safe_str_client(service->onion_address), + num_new_intro_points, + service->config.num_intro_points - num_intro_points, + num_intro_points); + /* We'll build those introduction point into the descriptor once we have + * confirmation that the circuits are opened and ready. However, + * indicate that this descriptor should be uploaded from now on. */ + desc->next_upload_time = now; + } + } +} + +/* Update descriptors for each service if needed. */ +static void +update_all_descriptors(time_t now) +{ + FOR_EACH_SERVICE_BEGIN(service) { + /* We'll try to update each descriptor that is if certain conditions apply + * in order for the descriptor to be updated. */ + FOR_EACH_DESCRIPTOR_BEGIN(service, desc) { + update_service_descriptor(service, desc, now); + } FOR_EACH_DESCRIPTOR_END; + } FOR_EACH_SERVICE_END; +} + +/* Return true iff the given intro point has expired that is it has been used + * for too long or we've reached our max seen INTRODUCE2 cell. */ +static int +intro_point_should_expire(const hs_service_intro_point_t *ip, + time_t now) +{ + tor_assert(ip); + + if (ip->introduce2_count >= ip->introduce2_max) { + goto expired; + } + + if (ip->time_to_expire <= now) { + goto expired; + } + + /* Not expiring. */ + return 0; + expired: + return 1; +} + +/* Go over the given set of intro points for each service and remove any + * invalid ones. The conditions for removal are: + * + * - The node doesn't exists anymore (not in consensus) + * OR + * - The intro point maximum circuit retry count has been reached and no + * circuit can be found associated with it. + * OR + * - The intro point has expired and we should pick a new one. + * + * If an intro point is removed, the circuit (if any) is immediately close. + * If a circuit can't be found, the intro point is kept if it hasn't reached + * its maximum circuit retry value and thus should be retried. */ +static void +cleanup_intro_points(hs_service_t *service, time_t now) +{ + tor_assert(service); + + /* For both descriptors, cleanup the intro points. */ + FOR_EACH_DESCRIPTOR_BEGIN(service, desc) { + /* Go over the current intro points we have, make sure they are still + * valid and remove any of them that aren't. */ + DIGEST256MAP_FOREACH_MODIFY(desc->intro_points.map, key, + hs_service_intro_point_t *, ip) { + const node_t *node = get_node_from_intro_point(ip); + origin_circuit_t *ocirc = get_intro_circuit(ip); + int has_expired = intro_point_should_expire(ip, now); + + /* We cleanup an intro point if it has expired or if we do not know the + * node_t anymore (removed from our latest consensus) or if we've + * reached the maximum number of retry with a non existing circuit. */ + if (has_expired || node == NULL || + (ocirc == NULL && + ip->circuit_retries >= MAX_INTRO_POINT_CIRCUIT_RETRIES)) { + MAP_DEL_CURRENT(key); + service_intro_point_free(ip); + /* XXX: Legacy code does NOT do that, it keeps the circuit open until + * a new descriptor is uploaded and then closed all expiring intro + * point circuit. Here, we close immediately and because we just + * discarded the intro point, a new one will be selected, a new + * descriptor created and uploaded. There is no difference to an + * attacker between the timing of a new consensus and intro point + * rotation (possibly?). */ + if (ocirc) { + /* After this, no new cells will be handled on the circuit. */ + circuit_mark_for_close(TO_CIRCUIT(ocirc), END_CIRC_REASON_FINISHED); + } + continue; + } + if (ocirc == NULL) { + /* Circuit disappeared so make sure the intro point is updated. By + * keeping the object in the descriptor, we'll be able to retry. */ + ip->circuit_established = 0; + } + } DIGEST256MAP_FOREACH_END; + } FOR_EACH_DESCRIPTOR_END; +} + +/** We just entered overlap period and we need to rotate our <b>service</b> + * descriptors */ +static void +rotate_service_descriptors(hs_service_t *service) +{ + if (service->desc_current) { + /* Close all IP circuits for the descriptor. */ + close_intro_circuits(&service->desc_current->intro_points); + /* We don't need this one anymore, we won't serve any clients coming with + * this service descriptor. */ + service_descriptor_free(service->desc_current); + } + /* The next one become the current one and emptying the next will trigger + * a descriptor creation for it. */ + service->desc_current = service->desc_next; + service->desc_next = NULL; +} + +/* Rotate descriptors for each service if needed. If we are just entering + * the overlap period, rotate them that is point the previous descriptor to + * the current and cleanup the previous one. A non existing current + * descriptor will trigger a descriptor build for the next time period. */ +static void +rotate_all_descriptors(time_t now) +{ + FOR_EACH_SERVICE_BEGIN(service) { + /* We are _not_ in the overlap period so skip rotation. */ + if (!hs_overlap_mode_is_active(NULL, now)) { + service->state.in_overlap_period = 0; + continue; + } + /* We've entered the overlap period already so skip rotation. */ + if (service->state.in_overlap_period) { + continue; + } + /* It's the first time the service encounters the overlap period so flag + * it in order to make sure we don't rotate at next check. */ + service->state.in_overlap_period = 1; + + /* If we have a next descriptor lined up, rotate the descriptors so that it + * becomes current. */ + if (service->desc_next) { + rotate_service_descriptors(service); + } + log_info(LD_REND, "We've just entered the overlap period. Service %s " + "descriptors have been rotated!", + safe_str_client(service->onion_address)); + } FOR_EACH_SERVICE_END; +} + /* Scheduled event run from the main loop. Make sure all our services are up * to date and ready for the other scheduled events. This includes looking at * the introduction points status and descriptor rotation time. */ static void run_housekeeping_event(time_t now) { - (void) now; + /* Note that nothing here opens circuit(s) nor uploads descriptor(s). We are + * simply moving things around or removing uneeded elements. */ + + FOR_EACH_SERVICE_BEGIN(service) { + /* Cleanup invalid intro points from the service descriptor. */ + cleanup_intro_points(service, now); + + /* At this point, the service is now ready to go through the scheduled + * events guaranteeing a valid state. Intro points might be missing from + * the descriptors after the cleanup but the update/build process will + * make sure we pick those missing ones. */ + } FOR_EACH_SERVICE_END; } /* Scheduled event run from the main loop. Make sure all descriptors are up to @@ -537,14 +1408,21 @@ run_housekeeping_event(time_t now) static void run_build_descriptor_event(time_t now) { - (void) now; /* For v2 services, this step happens in the upload event. */ /* Run v3+ events. */ - FOR_EACH_SERVICE_BEGIN(service) { - /* XXX: Actually build descriptors. */ - (void) service; - } FOR_EACH_SERVICE_END; + /* We start by rotating the descriptors only if needed. */ + rotate_all_descriptors(now); + + /* Then, we'll try to build new descriptors that we might need. The + * condition is that the next descriptor is non existing because it has + * been rotated or we just started up. */ + build_all_descriptors(now); + + /* Finally, we'll check if we should update the descriptors. Missing + * introduction points will be picked in this function which is useful for + * newly built descriptors. */ + update_all_descriptors(now); } /* Scheduled event run from the main loop. Make sure we have all the circuits @@ -552,8 +1430,6 @@ run_build_descriptor_event(time_t now) static void run_build_circuit_event(time_t now) { - (void) now; - /* Make sure we can actually have enough information to build internal * circuits as required by services. */ if (router_have_consensus_path() == CONSENSUS_PATH_UNKNOWN) { @@ -562,11 +1438,14 @@ run_build_circuit_event(time_t now) /* Run v2 check. */ if (num_rend_services() > 0) { - rend_consider_services_intro_points(); + rend_consider_services_intro_points(now); } + /* Run v3+ check. */ FOR_EACH_SERVICE_BEGIN(service) { /* XXX: Check every service for validity of circuits. */ + /* XXX: Make sure we have a retry period so we don't stress circuit + * creation. */ (void) service; } FOR_EACH_SERVICE_END; } @@ -672,27 +1551,10 @@ hs_service_free(hs_service_t *service) return; } - /* Free descriptors. */ - if (service->desc_current) { - hs_descriptor_free(service->desc_current->desc); - /* Wipe keys. */ - memwipe(&service->desc_current->signing_kp, 0, - sizeof(service->desc_current->signing_kp)); - memwipe(&service->desc_current->blinded_kp, 0, - sizeof(service->desc_current->blinded_kp)); - /* XXX: Free intro points. */ - tor_free(service->desc_current); - } - if (service->desc_next) { - hs_descriptor_free(service->desc_next->desc); - /* Wipe keys. */ - memwipe(&service->desc_next->signing_kp, 0, - sizeof(service->desc_next->signing_kp)); - memwipe(&service->desc_next->blinded_kp, 0, - sizeof(service->desc_next->blinded_kp)); - /* XXX: Free intro points. */ - tor_free(service->desc_next); - } + /* Free descriptors. Go over both descriptor with this loop. */ + FOR_EACH_DESCRIPTOR_BEGIN(service, desc) { + service_descriptor_free(desc); + } FOR_EACH_DESCRIPTOR_END; /* Free service configuration. */ service_clear_config(&service->config); |