diff options
Diffstat (limited to 'src/feature/hs/hs_circuit.c')
| -rw-r--r-- | src/feature/hs/hs_circuit.c | 228 |
1 files changed, 185 insertions, 43 deletions
diff --git a/src/feature/hs/hs_circuit.c b/src/feature/hs/hs_circuit.c index 5e213b5aba..90805a98b7 100644 --- a/src/feature/hs/hs_circuit.c +++ b/src/feature/hs/hs_circuit.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2017-2019, The Tor Project, Inc. */ +/* Copyright (c) 2017-2020, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** @@ -20,11 +20,13 @@ #include "feature/hs/hs_cell.h" #include "feature/hs/hs_circuit.h" #include "feature/hs/hs_circuitmap.h" +#include "feature/hs/hs_client.h" #include "feature/hs/hs_ident.h" #include "feature/hs/hs_service.h" #include "feature/nodelist/describe.h" #include "feature/nodelist/nodelist.h" #include "feature/rend/rendservice.h" +#include "feature/rend/rendclient.h" #include "feature/stats/rephist.h" #include "lib/crypt_ops/crypto_dh.h" #include "lib/crypt_ops/crypto_rand.h" @@ -40,7 +42,7 @@ #include "feature/nodelist/node_st.h" #include "core/or/origin_circuit_st.h" -/* A circuit is about to become an e2e rendezvous circuit. Check +/** A circuit is about to become an e2e rendezvous circuit. Check * <b>circ_purpose</b> and ensure that it's properly set. Return true iff * circuit purpose is properly set, otherwise return false. */ static int @@ -67,7 +69,7 @@ circuit_purpose_is_correct_for_rend(unsigned int circ_purpose, return 1; } -/* Create and return a crypt path for the final hop of a v3 prop224 rendezvous +/** Create and return a crypt path for the final hop of a v3 prop224 rendezvous * circuit. Initialize the crypt path crypto using the output material from the * ntor key exchange at <b>ntor_key_seed</b>. * @@ -101,7 +103,7 @@ create_rend_cpath(const uint8_t *ntor_key_seed, size_t seed_len, return cpath; } -/* We are a v2 legacy HS client: Create and return a crypt path for the hidden +/** We are a v2 legacy HS client: Create and return a crypt path for the hidden * service on the other side of the rendezvous circuit <b>circ</b>. Initialize * the crypt path crypto using the body of the RENDEZVOUS1 cell at * <b>rend_cell_body</b> (which must be at least DH1024_KEY_LEN+DIGEST_LEN @@ -152,7 +154,7 @@ create_rend_cpath_legacy(origin_circuit_t *circ, const uint8_t *rend_cell_body) return hop; } -/* Append the final <b>hop</b> to the cpath of the rend <b>circ</b>, and mark +/** Append the final <b>hop</b> to the cpath of the rend <b>circ</b>, and mark * <b>circ</b> ready for use to transfer HS relay cells. */ static void finalize_rend_circuit(origin_circuit_t *circ, crypt_path_t *hop, @@ -193,7 +195,7 @@ finalize_rend_circuit(origin_circuit_t *circ, crypt_path_t *hop, } } -/* For a given circuit and a service introduction point object, register the +/** For a given circuit and a service introduction point object, register the * intro circuit to the circuitmap. This supports legacy intro point. */ static void register_intro_circ(const hs_service_intro_point_t *ip, @@ -211,7 +213,7 @@ register_intro_circ(const hs_service_intro_point_t *ip, } } -/* Return the number of opened introduction circuit for the given circuit that +/** Return the number of opened introduction circuit for the given circuit that * is matching its identity key. */ static unsigned int count_opened_desc_intro_point_circuits(const hs_service_t *service, @@ -243,7 +245,7 @@ count_opened_desc_intro_point_circuits(const hs_service_t *service, return count; } -/* From a given service, rendezvous cookie and handshake info, create a +/** From a given service, rendezvous cookie and handshake info, create a * rendezvous point circuit identifier. This can't fail. */ STATIC hs_ident_circuit_t * create_rp_circuit_identifier(const hs_service_t *service, @@ -282,7 +284,7 @@ create_rp_circuit_identifier(const hs_service_t *service, return ident; } -/* From a given service and service intro point, create an introduction point +/** From a given service and service intro point, create an introduction point * circuit identifier. This can't fail. */ static hs_ident_circuit_t * create_intro_circuit_identifier(const hs_service_t *service, @@ -299,7 +301,7 @@ create_intro_circuit_identifier(const hs_service_t *service, return ident; } -/* For a given introduction point and an introduction circuit, send the +/** For a given introduction point and an introduction circuit, send the * ESTABLISH_INTRO cell. The service object is used for logging. This can fail * and if so, the circuit is closed and the intro point object is flagged * that the circuit is not established anymore which is important for the @@ -349,7 +351,7 @@ send_establish_intro(const hs_service_t *service, memwipe(payload, 0, sizeof(payload)); } -/* Return a string constant describing the anonymity of service. */ +/** Return a string constant describing the anonymity of service. */ static const char * get_service_anonymity_string(const hs_service_t *service) { @@ -360,7 +362,7 @@ get_service_anonymity_string(const hs_service_t *service) } } -/* For a given service, the ntor onion key and a rendezvous cookie, launch a +/** For a given service, the ntor onion key and a rendezvous cookie, launch a * circuit to the rendezvous point specified by the link specifiers. On * success, a circuit identifier is attached to the circuit with the needed * data. This function will try to open a circuit for a maximum value of @@ -469,7 +471,7 @@ launch_rendezvous_point_circuit(const hs_service_t *service, extend_info_free(info); } -/* Return true iff the given service rendezvous circuit circ is allowed for a +/** Return true iff the given service rendezvous circuit circ is allowed for a * relaunch to the rendezvous point. */ static int can_relaunch_service_rendezvous_point(const origin_circuit_t *circ) @@ -516,7 +518,7 @@ can_relaunch_service_rendezvous_point(const origin_circuit_t *circ) return 0; } -/* Retry the rendezvous point of circ by launching a new circuit to it. */ +/** Retry the rendezvous point of circ by launching a new circuit to it. */ static void retry_service_rendezvous_point(const origin_circuit_t *circ) { @@ -565,7 +567,7 @@ retry_service_rendezvous_point(const origin_circuit_t *circ) return; } -/* Using the given descriptor intro point ip, the node of the +/** Using the given descriptor intro point ip, the node of the * rendezvous point rp_node and the service's subcredential, populate the * already allocated intro1_data object with the needed key material and link * specifiers. @@ -618,11 +620,27 @@ setup_introduce1_data(const hs_desc_intro_point_t *ip, return ret; } +/** Helper: cleanup function for client circuit. This is for every HS version. + * It is called from hs_circ_cleanup_on_free() entry point. */ +static void +cleanup_on_free_client_circ(circuit_t *circ) +{ + tor_assert(circ); + + if (circuit_is_hs_v2(circ)) { + rend_client_circuit_cleanup_on_free(circ); + } else if (circuit_is_hs_v3(circ)) { + hs_client_circuit_cleanup_on_free(circ); + } + /* It is possible the circuit has an HS purpose but no identifier (rend_data + * or hs_ident). Thus possible that this passess through. */ +} + /* ========== */ /* Public API */ /* ========== */ -/* Return an introduction point circuit matching the given intro point object. +/** Return an introduction point circuit matching the given intro point object. * NULL is returned is no such circuit can be found. */ origin_circuit_t * hs_circ_service_get_intro_circ(const hs_service_intro_point_t *ip) @@ -637,7 +655,29 @@ hs_circ_service_get_intro_circ(const hs_service_intro_point_t *ip) } } -/* Called when we fail building a rendezvous circuit at some point other than +/** Return an introduction point established circuit matching the given intro + * point object. The circuit purpose has to be CIRCUIT_PURPOSE_S_INTRO. NULL + * is returned is no such circuit can be found. */ +origin_circuit_t * +hs_circ_service_get_established_intro_circ(const hs_service_intro_point_t *ip) +{ + origin_circuit_t *circ; + + tor_assert(ip); + + if (ip->base.is_only_legacy) { + circ = hs_circuitmap_get_intro_circ_v2_service_side(ip->legacy_key_digest); + } else { + circ = hs_circuitmap_get_intro_circ_v3_service_side( + &ip->auth_key_kp.pubkey); + } + + /* Only return circuit if it is established. */ + return (circ && TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_S_INTRO) ? + circ : NULL; +} + +/** Called when we fail building a rendezvous circuit at some point other than * the last hop: launches a new circuit to the same rendezvous point. This * supports legacy service. * @@ -677,7 +717,7 @@ hs_circ_retry_service_rendezvous_point(origin_circuit_t *circ) return; } -/* For a given service and a service intro point, launch a circuit to the +/** For a given service and a service intro point, launch a circuit to the * extend info ei. If the service is a single onion, and direct_conn is true, * a one-hop circuit will be requested. * @@ -738,7 +778,7 @@ hs_circ_launch_intro_point(hs_service_t *service, return ret; } -/* Called when a service introduction point circuit is done building. Given +/** Called when a service introduction point circuit is done building. Given * the service and intro point object, this function will send the * ESTABLISH_INTRO cell on the circuit. Return 0 on success. Return 1 if the * circuit has been repurposed to General because we already have too many @@ -807,7 +847,7 @@ hs_circ_service_intro_has_opened(hs_service_t *service, return ret; } -/* Called when a service rendezvous point circuit is done building. Given the +/** Called when a service rendezvous point circuit is done building. Given the * service and the circuit, this function will send a RENDEZVOUS1 cell on the * circuit using the information in the circuit identifier. If the cell can't * be sent, the circuit is closed. */ @@ -873,7 +913,7 @@ hs_circ_service_rp_has_opened(const hs_service_t *service, memwipe(payload, 0, sizeof(payload)); } -/* Circ has been expecting an INTRO_ESTABLISHED cell that just arrived. Handle +/** Circ has been expecting an INTRO_ESTABLISHED cell that just arrived. Handle * the INTRO_ESTABLISHED cell payload of length payload_len arriving on the * given introduction circuit circ. The service is only used for logging * purposes. Return 0 on success else a negative value. */ @@ -918,7 +958,7 @@ hs_circ_handle_intro_established(const hs_service_t *service, return ret; } -/* We just received an INTRODUCE2 cell on the established introduction circuit +/** We just received an INTRODUCE2 cell on the established introduction circuit * circ. Handle the INTRODUCE2 payload of size payload_len for the given * circuit and service. This cell is associated with the intro point object ip * and the subcredential. Return 0 on success else a negative value. */ @@ -985,7 +1025,7 @@ hs_circ_handle_introduce2(const hs_service_t *service, return ret; } -/* Circuit <b>circ</b> just finished the rend ntor key exchange. Use the key +/** Circuit <b>circ</b> just finished the rend ntor key exchange. Use the key * exchange output material at <b>ntor_key_seed</b> and setup <b>circ</b> to * serve as a rendezvous end-to-end circuit between the client and the * service. If <b>is_service_side</b> is set, then we are the hidden service @@ -1015,7 +1055,7 @@ hs_circuit_setup_e2e_rend_circ(origin_circuit_t *circ, return 0; } -/* We are a v2 legacy HS client and we just received a RENDEZVOUS1 cell +/** We are a v2 legacy HS client and we just received a RENDEZVOUS1 cell * <b>rend_cell_body</b> on <b>circ</b>. Finish up the DH key exchange and then * extend the crypt path of <b>circ</b> so that the hidden service is on the * other side. */ @@ -1040,7 +1080,7 @@ hs_circuit_setup_e2e_rend_circ_legacy_client(origin_circuit_t *circ, return 0; } -/* Given the introduction circuit intro_circ, the rendezvous circuit +/** Given the introduction circuit intro_circ, the rendezvous circuit * rend_circ, a descriptor intro point object ip and the service's * subcredential, send an INTRODUCE1 cell on intro_circ. * @@ -1125,7 +1165,7 @@ hs_circ_send_introduce1(origin_circuit_t *intro_circ, return ret; } -/* Send an ESTABLISH_RENDEZVOUS cell along the rendezvous circuit circ. On +/** Send an ESTABLISH_RENDEZVOUS cell along the rendezvous circuit circ. On * success, 0 is returned else -1 and the circuit is marked for close. */ int hs_circ_send_establish_rendezvous(origin_circuit_t *circ) @@ -1176,30 +1216,132 @@ hs_circ_send_establish_rendezvous(origin_circuit_t *circ) return -1; } -/* We are about to close or free this <b>circ</b>. Clean it up from any - * related HS data structures. This function can be called multiple times - * safely for the same circuit. */ +/** Circuit cleanup strategy: + * + * What follows is a series of functions that notifies the HS subsystem of 3 + * different circuit cleanup phase: close, free and repurpose. + * + * Tor can call any of those in any orders so they have to be safe between + * each other. In other words, the free should never depend on close to be + * called before. + * + * The "on_close()" is called from circuit_mark_for_close() which is + * considered the tor fast path and thus as little work as possible should + * done in that function. Currently, we only remove the circuit from the HS + * circuit map and move on. + * + * The "on_free()" is called from circuit circuit_free_() and it is very + * important that at the end of the function, no state or objects related to + * this circuit remains alive. + * + * The "on_repurpose()" is called from circuit_change_purpose() for which we + * simply remove it from the HS circuit map. We do not have other cleanup + * requirements after that. + * + * NOTE: The onion service code, specifically the service code, cleans up + * lingering objects or state if any of its circuit disappear which is why + * our cleanup strategy doesn't involve any service specific actions. As long + * as the circuit is removed from the HS circuit map, it won't be used. + */ + +/** We are about to close this <b>circ</b>. Clean it up from any related HS + * data structures. This function can be called multiple times safely for the + * same circuit. */ +void +hs_circ_cleanup_on_close(circuit_t *circ) +{ + tor_assert(circ); + + /* On close, we simply remove it from the circuit map. It can not be used + * anymore. We keep this code path fast and lean. */ + + if (circ->hs_token) { + hs_circuitmap_remove_circuit(circ); + } +} + +/** We are about to free this <b>circ</b>. Clean it up from any related HS + * data structures. This function can be called multiple times safely for the + * same circuit. */ void -hs_circ_cleanup(circuit_t *circ) +hs_circ_cleanup_on_free(circuit_t *circ) { tor_assert(circ); - /* If it's a service-side intro circ, notify the HS subsystem for the intro - * point circuit closing so it can be dealt with cleanly. */ - if (circ->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO || - circ->purpose == CIRCUIT_PURPOSE_S_INTRO) { - hs_service_intro_circ_has_closed(TO_ORIGIN_CIRCUIT(circ)); + /* NOTE: Bulk of the work of cleaning up a circuit is done here. */ + + if (circuit_purpose_is_hs_client(circ->purpose)) { + cleanup_on_free_client_circ(circ); } - /* Clear HS circuitmap token for this circ (if any). Very important to be - * done after the HS subsystem has been notified of the close else the - * circuit will not be found. - * - * We do this at the close if possible because from that point on, the - * circuit is good as dead. We can't rely on removing it in the circuit - * free() function because we open a race window between the close and free - * where we can't register a new circuit for the same intro point. */ + /* We have no assurance that the given HS circuit has been closed before and + * thus removed from the HS map. This actually happens in unit tests. */ + if (circ->hs_token) { + hs_circuitmap_remove_circuit(circ); + } +} + +/** We are about to repurpose this <b>circ</b>. Clean it up from any related + * HS data structures. This function can be called multiple times safely for + * the same circuit. */ +void +hs_circ_cleanup_on_repurpose(circuit_t *circ) +{ + tor_assert(circ); + + /* On repurpose, we simply remove it from the circuit map but we do not do + * the on_free actions since we don't treat a repurpose as something we need + * to report in the client cache failure. */ + if (circ->hs_token) { hs_circuitmap_remove_circuit(circ); } } + +/** Return true iff the given established client rendezvous circuit was sent + * into the INTRODUCE1 cell. This is called so we can take a decision on + * expiring or not the circuit. + * + * The caller MUST make sure the circuit is an established client rendezvous + * circuit (purpose: CIRCUIT_PURPOSE_C_REND_READY). + * + * This function supports all onion service versions. */ +bool +hs_circ_is_rend_sent_in_intro1(const origin_circuit_t *circ) +{ + tor_assert(circ); + /* This can only be called for a rendezvous circuit that is an established + * confirmed rendezsvous circuit but without an introduction ACK. */ + tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_REND_READY); + + /* The v2 and v3 circuit are handled differently: + * + * v2: A circ's pending_final_cpath field is non-NULL iff it is a rend circ + * and we have tried to send an INTRODUCE1 cell specifying it. Thus, if the + * pending_final_cpath field *is* NULL, then we want to not spare it. + * + * v3: When the INTRODUCE1 cell is sent, the introduction encryption public + * key is copied in the rendezvous circuit hs identifier. If it is a valid + * key, we know that this circuit is waiting the ACK on the introduction + * circuit. We want to _not_ spare the circuit if the key was never set. */ + + if (circ->rend_data) { + /* v2. */ + if (circ->build_state && circ->build_state->pending_final_cpath != NULL) { + return true; + } + } else if (circ->hs_ident) { + /* v3. */ + if (curve25519_public_key_is_ok(&circ->hs_ident->intro_enc_pk)) { + return true; + } + } else { + /* A circuit with an HS purpose without an hs_ident or rend_data in theory + * can not happen. In case, scream loudly and return false to the caller + * that the rendezvous was not sent in the INTRO1 cell. */ + tor_assert_nonfatal_unreached(); + } + + /* The rendezvous has not been specified in the INTRODUCE1 cell. */ + return false; +} |