/** Process a 'create' <b>cell</b> that just arrived from <b>chan</b>. Make a * new circuit with the p_circ_id specified in cell. Put the circuit in state * onionskin_pending, and pass the onionskin to the cpuworker. Circ will get * picked up again when the cpuworker finishes decrypting it. */ static void command_process_create_cell(cell_t *cell, channel_t *chan) { or_circuit_t *circ; const or_options_t *options = get_options(); int id_is_high; tor_assert(cell); tor_assert(chan); log_debug(LD_OR, "Got a CREATE cell for circ_id %d on channel " U64_FORMAT " (%p)", cell->circ_id, U64_PRINTF_ARG(chan->global_identifier), chan); if (we_are_hibernating()) { log_info(LD_OR, "Received create cell but we're shutting down. Sending back " "destroy."); channel_send_destroy(cell->circ_id, chan, END_CIRC_REASON_HIBERNATING); return; } if (!server_mode(options) || (!public_server_mode(options) && channel_is_outgoing(chan))) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received create cell (type %d) from %s, but we're connected " "to it as a client. " "Sending back a destroy.", (int)cell->command, channel_get_canonical_remote_descr(chan)); channel_send_destroy(cell->circ_id, chan, END_CIRC_REASON_TORPROTOCOL); return; } /* If the high bit of the circuit ID is not as expected, close the * circ. */ id_is_high = cell->circ_id & (1<<15); if ((id_is_high && chan->circ_id_type == CIRC_ID_TYPE_HIGHER) || (!id_is_high && chan->circ_id_type == CIRC_ID_TYPE_LOWER)) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received create cell with unexpected circ_id %d. Closing.", cell->circ_id); channel_send_destroy(cell->circ_id, chan, END_CIRC_REASON_TORPROTOCOL); return; } if (circuit_id_in_use_on_channel(cell->circ_id, chan)) { const node_t *node = node_get_by_id(chan->identity_digest); log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received CREATE cell (circID %d) for known circ. " "Dropping (age %d).", cell->circ_id, (int)(time(NULL) - channel_when_created(chan))); if (node) { char *p = esc_for_log(node_get_platform(node)); log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Details: router %s, platform %s.", node_describe(node), p); tor_free(p); } return; } circ = or_circuit_new(cell->circ_id, chan); circ->base_.purpose = CIRCUIT_PURPOSE_OR; circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_ONIONSKIN_PENDING); if (cell->command == CELL_CREATE) { char *onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN); memcpy(onionskin, cell->payload, ONIONSKIN_CHALLENGE_LEN); /* hand it off to the cpuworkers, and then return. */ if (assign_onionskin_to_cpuworker(NULL, circ, onionskin) < 0) { log_debug(LD_GENERAL,"Failed to hand off onionskin. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_RESOURCELIMIT); return; } log_debug(LD_OR,"success: handed off onionskin."); } else { /* This is a CREATE_FAST cell; we can handle it immediately without using * a CPU worker. */ char keys[CPATH_KEY_MATERIAL_LEN]; char reply[DIGEST_LEN*2]; tor_assert(cell->command == CELL_CREATE_FAST); /* Make sure we never try to use the OR connection on which we * received this cell to satisfy an EXTEND request, */ channel_mark_client(chan); if (fast_server_handshake(cell->payload, (uint8_t*)reply, (uint8_t*)keys, sizeof(keys))<0) { log_warn(LD_OR,"Failed to generate key material. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL); return; } if (onionskin_answer(circ, CELL_CREATED_FAST, reply, keys)<0) { log_warn(LD_OR,"Failed to reply to CREATE_FAST cell. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL); return; } } }
/** Process a 'create' <b>cell</b> that just arrived from <b>chan</b>. Make a * new circuit with the p_circ_id specified in cell. Put the circuit in state * onionskin_pending, and pass the onionskin to the cpuworker. Circ will get * picked up again when the cpuworker finishes decrypting it. */ static void command_process_create_cell(cell_t *cell, channel_t *chan) { or_circuit_t *circ; const or_options_t *options = get_options(); int id_is_high; create_cell_t *create_cell; tor_assert(cell); tor_assert(chan); log_debug(LD_OR, "Got a CREATE cell for circ_id %u on channel " U64_FORMAT " (%p)", (unsigned)cell->circ_id, U64_PRINTF_ARG(chan->global_identifier), chan); if (we_are_hibernating()) { log_info(LD_OR, "Received create cell but we're shutting down. Sending back " "destroy."); channel_send_destroy(cell->circ_id, chan, END_CIRC_REASON_HIBERNATING); return; } if (!server_mode(options) || (!public_server_mode(options) && channel_is_outgoing(chan))) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received create cell (type %d) from %s, but we're connected " "to it as a client. " "Sending back a destroy.", (int)cell->command, channel_get_canonical_remote_descr(chan)); channel_send_destroy(cell->circ_id, chan, END_CIRC_REASON_TORPROTOCOL); return; } if (cell->circ_id == 0) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received a create cell (type %d) from %s with zero circID; " " ignoring.", (int)cell->command, channel_get_actual_remote_descr(chan)); return; } /* If the high bit of the circuit ID is not as expected, close the * circ. */ if (chan->wide_circ_ids) id_is_high = cell->circ_id & (1u<<31); else id_is_high = cell->circ_id & (1u<<15); if ((id_is_high && chan->circ_id_type == CIRC_ID_TYPE_HIGHER) || (!id_is_high && chan->circ_id_type == CIRC_ID_TYPE_LOWER)) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received create cell with unexpected circ_id %u. Closing.", (unsigned)cell->circ_id); channel_send_destroy(cell->circ_id, chan, END_CIRC_REASON_TORPROTOCOL); return; } if (circuit_id_in_use_on_channel(cell->circ_id, chan)) { const node_t *node = node_get_by_id(chan->identity_digest); log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received CREATE cell (circID %u) for known circ. " "Dropping (age %d).", (unsigned)cell->circ_id, (int)(time(NULL) - channel_when_created(chan))); if (node) { char *p = esc_for_log(node_get_platform(node)); log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Details: router %s, platform %s.", node_describe(node), p); tor_free(p); } return; } circ = or_circuit_new(cell->circ_id, chan); circ->base_.purpose = CIRCUIT_PURPOSE_OR; circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_ONIONSKIN_PENDING); create_cell = tor_malloc_zero(sizeof(create_cell_t)); if (create_cell_parse(create_cell, cell) < 0) { tor_free(create_cell); log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bogus/unrecognized create cell; closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); return; } if (create_cell->handshake_type != ONION_HANDSHAKE_TYPE_FAST) { /* hand it off to the cpuworkers, and then return. */ if (connection_or_digest_is_known_relay(chan->identity_digest)) rep_hist_note_circuit_handshake_requested(create_cell->handshake_type); if (assign_onionskin_to_cpuworker(NULL, circ, create_cell) < 0) { log_debug(LD_GENERAL,"Failed to hand off onionskin. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_RESOURCELIMIT); return; } log_debug(LD_OR,"success: handed off onionskin."); } else { /* This is a CREATE_FAST cell; we can handle it immediately without using * a CPU worker. */ uint8_t keys[CPATH_KEY_MATERIAL_LEN]; uint8_t rend_circ_nonce[DIGEST_LEN]; int len; created_cell_t created_cell; /* Make sure we never try to use the OR connection on which we * received this cell to satisfy an EXTEND request, */ channel_mark_client(chan); memset(&created_cell, 0, sizeof(created_cell)); len = onion_skin_server_handshake(ONION_HANDSHAKE_TYPE_FAST, create_cell->onionskin, create_cell->handshake_len, NULL, created_cell.reply, keys, CPATH_KEY_MATERIAL_LEN, rend_circ_nonce); tor_free(create_cell); if (len < 0) { log_warn(LD_OR,"Failed to generate key material. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL); tor_free(create_cell); return; } created_cell.cell_type = CELL_CREATED_FAST; created_cell.handshake_len = len; if (onionskin_answer(circ, &created_cell, (const char *)keys, rend_circ_nonce)<0) { log_warn(LD_OR,"Failed to reply to CREATE_FAST cell. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL); return; } memwipe(keys, 0, sizeof(keys)); } }