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- /* Copyright (c) 2001 Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /* $Id$ */
- const char command_c_id[] =
- "$Id$";
- /**
- * \file command.c
- * \brief Functions for processing incoming cells.
- **/
- /* In-points to command.c:
- *
- * - command_process_cell(), called from
- * connection_or_process_cells_from_inbuf() in connection_or.c
- */
- #include "or.h"
- /** Keep statistics about how many of each type of cell we've received. */
- uint64_t stats_n_padding_cells_processed = 0;
- uint64_t stats_n_create_cells_processed = 0;
- uint64_t stats_n_created_cells_processed = 0;
- uint64_t stats_n_relay_cells_processed = 0;
- uint64_t stats_n_destroy_cells_processed = 0;
- uint64_t stats_n_versions_cells_processed = 0;
- uint64_t stats_n_netinfo_cells_processed = 0;
- uint64_t stats_n_cert_cells_processed = 0;
- uint64_t stats_n_link_auth_cells_processed = 0;
- /* These are the main functions for processing cells */
- static void command_process_create_cell(cell_t *cell, or_connection_t *conn);
- static void command_process_created_cell(cell_t *cell, or_connection_t *conn);
- static void command_process_relay_cell(cell_t *cell, or_connection_t *conn);
- static void command_process_destroy_cell(cell_t *cell, or_connection_t *conn);
- static void command_process_versions_cell(var_cell_t *cell,
- or_connection_t *conn);
- static void command_process_netinfo_cell(cell_t *cell, or_connection_t *conn);
- #if 0
- static void command_process_cert_cell(var_cell_t *cell, or_connection_t *conn);
- static void command_process_link_auth_cell(cell_t *cell,or_connection_t *conn);
- #endif
- #ifdef KEEP_TIMING_STATS
- /** This is a wrapper function around the actual function that processes the
- * <b>cell</b> that just arrived on <b>conn</b>. Increment <b>*time</b>
- * by the number of microseconds used by the call to <b>*func(cell, conn)</b>.
- */
- static void
- command_time_process_cell(cell_t *cell, or_connection_t *conn, int *time,
- void (*func)(cell_t *, or_connection_t *))
- {
- struct timeval start, end;
- long time_passed;
- tor_gettimeofday(&start);
- (*func)(cell, conn);
- tor_gettimeofday(&end);
- time_passed = tv_udiff(&start, &end) ;
- if (time_passed > 10000) { /* more than 10ms */
- log_debug(LD_OR,"That call just took %ld ms.",time_passed/1000);
- }
- if (time_passed < 0) {
- log_info(LD_GENERAL,"That call took us back in time!");
- time_passed = 0;
- }
- *time += time_passed;
- }
- #endif
- /** Process a <b>cell</b> that was just received on <b>conn</b>. Keep internal
- * statistics about how many of each cell we've processed so far
- * this second, and the total number of microseconds it took to
- * process each type of cell.
- */
- void
- command_process_cell(cell_t *cell, or_connection_t *conn)
- {
- #ifdef KEEP_TIMING_STATS
- /* how many of each cell have we seen so far this second? needs better
- * name. */
- static int num_create=0, num_created=0, num_relay=0, num_destroy=0;
- /* how long has it taken to process each type of cell? */
- static int create_time=0, created_time=0, relay_time=0, destroy_time=0;
- static time_t current_second = 0; /* from previous calls to time */
- time_t now = time(NULL);
- if (now > current_second) { /* the second has rolled over */
- /* print stats */
- log_info(LD_OR,
- "At end of second: %d creates (%d ms), %d createds (%d ms), "
- "%d relays (%d ms), %d destroys (%d ms)",
- num_create, create_time/1000,
- num_created, created_time/1000,
- num_relay, relay_time/1000,
- num_destroy, destroy_time/1000);
- /* zero out stats */
- num_create = num_created = num_relay = num_destroy = 0;
- create_time = created_time = relay_time = destroy_time = 0;
- /* remember which second it is, for next time */
- current_second = now;
- }
- #endif
- #ifdef KEEP_TIMING_STATS
- #define PROCESS_CELL(tp, cl, cn) STMT_BEGIN { \
- ++num ## tp; \
- command_time_process_cell(cl, cn, & tp ## time , \
- command_process_ ## tp ## _cell); \
- } STMT_END
- #else
- #define PROCESS_CELL(tp, cl, cn) command_process_ ## tp ## _cell(cl, cn)
- #endif
- /*XXXX020 reject all but VERSIONS, NETINFO, CERT, LINK_AUTH when
- * handshaking. */
- switch (cell->command) {
- case CELL_PADDING:
- ++stats_n_padding_cells_processed;
- /* do nothing */
- break;
- case CELL_CREATE:
- case CELL_CREATE_FAST:
- ++stats_n_create_cells_processed;
- PROCESS_CELL(create, cell, conn);
- break;
- case CELL_CREATED:
- case CELL_CREATED_FAST:
- ++stats_n_created_cells_processed;
- PROCESS_CELL(created, cell, conn);
- break;
- case CELL_RELAY:
- case CELL_RELAY_EARLY:
- ++stats_n_relay_cells_processed;
- PROCESS_CELL(relay, cell, conn);
- break;
- case CELL_DESTROY:
- ++stats_n_destroy_cells_processed;
- PROCESS_CELL(destroy, cell, conn);
- break;
- case CELL_VERSIONS:
- tor_fragile_assert();
- break;
- case CELL_NETINFO:
- ++stats_n_netinfo_cells_processed;
- PROCESS_CELL(netinfo, cell, conn);
- break;
- default:
- log_fn(LOG_INFO, LD_PROTOCOL,
- "Cell of unknown type (%d) received. Dropping.", cell->command);
- break;
- }
- }
- /** Process a <b>cell</b> that was just received on <b>conn</b>. Keep internal
- * statistics about how many of each cell we've processed so far
- * this second, and the total number of microseconds it took to
- * process each type of cell.
- */
- void
- command_process_var_cell(var_cell_t *cell, or_connection_t *conn)
- {
- #ifdef KEEP_TIMING_STATS
- /* how many of each cell have we seen so far this second? needs better
- * name. */
- static int num_versions=0, num_cert=0;
- time_t now = time(NULL);
- if (now > current_second) { /* the second has rolled over */
- /* print stats */
- log_info(LD_OR,
- "At end of second: %d versions (%d ms), %d cert (%d ms)",
- num_versions, versions_time/1000,
- cert, cert_time/1000);
- num_versions = num_cert = 0;
- versions_time = cert_time = 0;
- /* remember which second it is, for next time */
- current_second = now;
- }
- #endif
- /*XXXX020 reject all when not handshaking. */
- switch (cell->command) {
- case CELL_VERSIONS:
- ++stats_n_versions_cells_processed;
- PROCESS_CELL(versions, cell, conn);
- break;
- default:
- log_warn(LD_BUG,
- "Variable-length cell of unknown type (%d) received.",
- cell->command);
- tor_fragile_assert();
- break;
- }
- }
- /** Process a 'create' <b>cell</b> that just arrived from <b>conn</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, or_connection_t *conn)
- {
- or_circuit_t *circ;
- int id_is_high;
- if (we_are_hibernating()) {
- log_info(LD_OR,
- "Received create cell but we're shutting down. Sending back "
- "destroy.");
- connection_or_send_destroy(cell->circ_id, conn,
- END_CIRC_REASON_HIBERNATING);
- return;
- }
- if (!server_mode(get_options())) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Received create cell (type %d) from %s:%d, but we're a client. "
- "Sending back a destroy.",
- (int)cell->command, conn->_base.address, conn->_base.port);
- connection_or_send_destroy(cell->circ_id, conn,
- 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 && conn->circ_id_type == CIRC_ID_TYPE_HIGHER) ||
- (!id_is_high && conn->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);
- connection_or_send_destroy(cell->circ_id, conn,
- END_CIRC_REASON_TORPROTOCOL);
- return;
- }
- if (circuit_get_by_circid_orconn(cell->circ_id, conn)) {
- routerinfo_t *router = router_get_by_digest(conn->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) - conn->_base.timestamp_created));
- if (router)
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Details: nickname \"%s\", platform %s.",
- router->nickname, escaped(router->platform));
- return;
- }
- circ = or_circuit_new(cell->circ_id, conn);
- circ->_base.purpose = CIRCUIT_PURPOSE_OR;
- circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_ONIONSKIN_PENDING);
- if (cell->command == CELL_CREATE) {
- circ->_base.onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
- memcpy(circ->_base.onionskin, cell->payload, ONIONSKIN_CHALLENGE_LEN);
- /* hand it off to the cpuworkers, and then return. */
- if (assign_to_cpuworker(NULL, CPUWORKER_TASK_ONION, circ) < 0) {
- log_warn(LD_GENERAL,"Failed to hand off onionskin. Closing.");
- circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
- 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);
- if (fast_server_handshake(cell->payload, reply, 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 'created' <b>cell</b> that just arrived from <b>conn</b>.
- * Find the circuit
- * that it's intended for. If we're not the origin of the circuit, package
- * the 'created' cell in an 'extended' relay cell and pass it back. If we
- * are the origin of the circuit, send it to circuit_finish_handshake() to
- * finish processing keys, and then call circuit_send_next_onion_skin() to
- * extend to the next hop in the circuit if necessary.
- */
- static void
- command_process_created_cell(cell_t *cell, or_connection_t *conn)
- {
- circuit_t *circ;
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- if (!circ) {
- log_info(LD_OR,
- "(circID %d) unknown circ (probably got a destroy earlier). "
- "Dropping.", cell->circ_id);
- return;
- }
- if (circ->n_circ_id != cell->circ_id) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,
- "got created cell from Tor client? Closing.");
- circuit_mark_for_close(circ, END_CIRC_REASON_TORPROTOCOL);
- return;
- }
- if (CIRCUIT_IS_ORIGIN(circ)) { /* we're the OP. Handshake this. */
- origin_circuit_t *origin_circ = TO_ORIGIN_CIRCUIT(circ);
- int err_reason = 0;
- log_debug(LD_OR,"at OP. Finishing handshake.");
- if ((err_reason = circuit_finish_handshake(origin_circ, cell->command,
- cell->payload)) < 0) {
- log_warn(LD_OR,"circuit_finish_handshake failed.");
- circuit_mark_for_close(circ, -err_reason);
- return;
- }
- log_debug(LD_OR,"Moving to next skin.");
- if ((err_reason = circuit_send_next_onion_skin(origin_circ)) < 0) {
- log_info(LD_OR,"circuit_send_next_onion_skin failed.");
- /* XXX push this circuit_close lower */
- circuit_mark_for_close(circ, -err_reason);
- return;
- }
- } else { /* pack it into an extended relay cell, and send it. */
- log_debug(LD_OR,
- "Converting created cell to extended relay cell, sending.");
- relay_send_command_from_edge(0, circ, RELAY_COMMAND_EXTENDED,
- cell->payload, ONIONSKIN_REPLY_LEN,
- NULL);
- }
- }
- /** Process a 'relay' <b>cell</b> that just arrived from <b>conn</b>. Make sure
- * it came in with a recognized circ_id. Pass it on to
- * circuit_receive_relay_cell() for actual processing.
- */
- static void
- command_process_relay_cell(cell_t *cell, or_connection_t *conn)
- {
- circuit_t *circ;
- int reason, direction;
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- if (!circ) {
- log_debug(LD_OR,
- "unknown circuit %d on connection from %s:%d. Dropping.",
- cell->circ_id, conn->_base.address, conn->_base.port);
- return;
- }
- if (circ->state == CIRCUIT_STATE_ONIONSKIN_PENDING) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit in create_wait. Closing.");
- circuit_mark_for_close(circ, END_CIRC_REASON_TORPROTOCOL);
- return;
- }
- if (CIRCUIT_IS_ORIGIN(circ)) {
- /* if we're a relay and treating connections with recent local
- * traffic better, then this is one of them. */
- conn->client_used = time(NULL);
- }
- if (!CIRCUIT_IS_ORIGIN(circ) &&
- cell->circ_id == TO_OR_CIRCUIT(circ)->p_circ_id)
- direction = CELL_DIRECTION_OUT;
- else
- direction = CELL_DIRECTION_IN;
- if ((reason = circuit_receive_relay_cell(cell, circ, direction)) < 0) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit_receive_relay_cell "
- "(%s) failed. Closing.",
- direction==CELL_DIRECTION_OUT?"forward":"backward");
- circuit_mark_for_close(circ, -reason);
- }
- }
- /** Process a 'destroy' <b>cell</b> that just arrived from
- * <b>conn</b>. Find the circ that it refers to (if any).
- *
- * If the circ is in state
- * onionskin_pending, then call onion_pending_remove() to remove it
- * from the pending onion list (note that if it's already being
- * processed by the cpuworker, it won't be in the list anymore; but
- * when the cpuworker returns it, the circuit will be gone, and the
- * cpuworker response will be dropped).
- *
- * Then mark the circuit for close (which marks all edges for close,
- * and passes the destroy cell onward if necessary).
- */
- static void
- command_process_destroy_cell(cell_t *cell, or_connection_t *conn)
- {
- circuit_t *circ;
- int reason;
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- reason = (uint8_t)cell->payload[0];
- if (!circ) {
- log_info(LD_OR,"unknown circuit %d on connection from %s:%d. Dropping.",
- cell->circ_id, conn->_base.address, conn->_base.port);
- return;
- }
- log_debug(LD_OR,"Received for circID %d.",cell->circ_id);
- if (!CIRCUIT_IS_ORIGIN(circ) &&
- cell->circ_id == TO_OR_CIRCUIT(circ)->p_circ_id) {
- /* the destroy came from behind */
- circuit_set_p_circid_orconn(TO_OR_CIRCUIT(circ), 0, NULL);
- circuit_mark_for_close(circ, reason|END_CIRC_REASON_FLAG_REMOTE);
- } else { /* the destroy came from ahead */
- circuit_set_n_circid_orconn(circ, 0, NULL);
- if (CIRCUIT_IS_ORIGIN(circ)) {
- circuit_mark_for_close(circ, reason|END_CIRC_REASON_FLAG_REMOTE);
- } else {
- char payload[1];
- log_debug(LD_OR, "Delivering 'truncated' back.");
- payload[0] = (char)reason;
- relay_send_command_from_edge(0, circ, RELAY_COMMAND_TRUNCATED,
- payload, sizeof(payload), NULL);
- }
- }
- }
- /** Process a 'versions' cell. The current link protocol version must be 0
- * to indicate that no version has yet been negotiated. DOCDOC say more. */
- static void
- command_process_versions_cell(var_cell_t *cell, or_connection_t *conn)
- {
- int highest_supported_version = 0;
- const char *cp, *end;
- if (conn->link_proto != 0 ||
- conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING ||
- (conn->handshake_state && conn->handshake_state->received_versions)) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Received a VERSIONS cell on a connection with its version "
- "already set to %d; dropping", (int) conn->link_proto);
- return;
- }
- tor_assert(conn->handshake_state);
- end = cell->payload + cell->payload_len;
- for (cp = cell->payload; cp+1 < end; ++cp) {
- uint16_t v = ntohs(get_uint16(cp));
- if (v == 1 || v == 2) {
- if (v > highest_supported_version)
- highest_supported_version = v;
- }
- }
- if (!highest_supported_version) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Couldn't find a version in common between my version list and the "
- "list in the VERSIONS cell; closing connection.");
- connection_mark_for_close(TO_CONN(conn));
- return;
- }
- conn->link_proto = highest_supported_version;
- conn->handshake_state->received_versions = 1;
- #if 0
- /*XXXX020 not right; references dead functions */
- if (highest_supported_version >= 2) {
- if (connection_or_send_netinfo(conn) < 0 ||
- connection_or_send_cert(conn) < 0) {
- connection_mark_for_close(TO_CONN(conn));
- return;
- }
- if (conn->handshake_state->started_here)
- connection_or_send_link_auth(conn);
- } else {
- /* XXXX020 finish v1 verification. */
- }
- #endif
- }
- /** Process a 'netinfo' cell. DOCDOC say more. */
- static void
- command_process_netinfo_cell(cell_t *cell, or_connection_t *conn)
- {
- time_t timestamp;
- uint8_t my_addr_type;
- uint8_t my_addr_len;
- const char *my_addr_ptr;
- const char *cp, *end;
- uint8_t n_other_addrs;
- time_t now = time(NULL);
- if (conn->link_proto < 2) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Received a NETINFO cell on %s connection; dropping.",
- conn->link_proto == 0 ? "non-versioned" : "a v1");
- return;
- }
- if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Received a NETINFO cell on a non-handshaking; dropping.");
- return;
- }
- tor_assert(conn->handshake_state &&
- conn->handshake_state->received_versions);
- if (conn->handshake_state->received_netinfo) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Received a duplicate NETINFO cell; dropping.");
- return;
- }
- /* Decode the cell. */
- timestamp = ntohl(get_uint32(cell->payload));
- if (abs(now - conn->handshake_state->sent_versions_at) < 180) {
- conn->handshake_state->apparent_skew = now - timestamp;
- }
- my_addr_type = (uint8_t) cell->payload[4];
- my_addr_len = (uint8_t) cell->payload[5];
- my_addr_ptr = cell->payload + 6;
- end = cell->payload + CELL_PAYLOAD_SIZE;
- cp = cell->payload + 6 + my_addr_len;
- if (cp >= end) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Addresses too long in netinfo cell; closing connection.");
- connection_mark_for_close(TO_CONN(conn));
- return;
- } else if (my_addr_type == RESOLVED_TYPE_IPV4 && my_addr_len == 4) {
- conn->handshake_state->my_apparent_addr = ntohl(get_uint32(my_addr_ptr));
- }
- n_other_addrs = (uint8_t) *cp++;
- while (n_other_addrs && cp < end-2) {
- /* Consider all the other addresses; if any matches, this connection is
- * "canonical." */
- uint8_t other_addr_type = (uint8_t) *cp++;
- uint8_t other_addr_len = (uint8_t) *cp++;
- if (cp + other_addr_len >= end) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Address too long in netinfo cell; closing connection.");
- connection_mark_for_close(TO_CONN(conn));
- return;
- }
- if (other_addr_type == RESOLVED_TYPE_IPV4 && other_addr_len == 4) {
- uint32_t addr = ntohl(get_uint32(cp));
- if (addr == conn->real_addr) {
- conn->handshake_state->apparently_canonical = 1;
- break;
- }
- }
- cp += other_addr_len;
- --n_other_addrs;
- }
- conn->handshake_state->received_netinfo = 1;
- }
- /*XXXX020 move to connection_or.c */
- /** DOCDOC Called when we're done authenticating; act on stuff we
- * learned in netinfo. */
- int
- connection_or_act_on_netinfo(or_connection_t *conn)
- {
- long delta;
- if (!conn->handshake_state)
- return -1;
- tor_assert(conn->handshake_state->authenticated != 0);
- delta = conn->handshake_state->apparent_skew;
- /*XXXX020 magic number 3600 */
- if (abs(delta) > 3600 &&
- router_get_by_digest(conn->identity_digest)) {
- char dbuf[64];
- /*XXXX020 not always warn!*/
- format_time_interval(dbuf, sizeof(dbuf), delta);
- log_fn(LOG_WARN, LD_HTTP, "Received NETINFO cell with skewed time from "
- "server at %s:%d. It seems that our clock is %s by %s, or "
- "that theirs is %s. Tor requires an accurate clock to work: "
- "please check your time and date settings.",
- conn->_base.address, (int)conn->_base.port,
- delta>0 ? "ahead" : "behind", dbuf,
- delta>0 ? "behind" : "ahead");
- control_event_general_status(LOG_WARN,
- "CLOCK_SKEW SKEW=%ld SOURCE=OR:%s:%d",
- delta, conn->_base.address, conn->_base.port);
- }
- /* XXX020 possibly, learn my address from my_apparent_addr */
- if (conn->handshake_state->apparently_canonical) {
- conn->is_canonical = 1;
- }
- return 0;
- }
- #if 0
- /*DOCDOC*/
- static void
- command_process_cert_cell(var_cell_t *cell, or_connection_t *conn)
- {
- int n_certs = 0;
- uint16_t conn_cert_len = 0, id_cert_len = 0;
- const char *conn_cert = NULL, *id_cert = NULL;
- const char *cp, *end;
- int done = 0;
- if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Got CERT cell when not handshaking. "
- "Ignoring.");
- return;
- }
- tor_assert(conn->handshake_state);
- if (!conn->handshake_state->received_versions ||
- !conn->handshake_state->received_netinfo) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Got CERT cell before VERSIONS and "
- "NETINFO. Closing the connection.");
- goto err;
- }
- if (conn->handshake_state->received_certs) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Got duplicate CERT cell. "
- "Closing the connection.");
- goto err;
- }
- cp = cell->payload;
- end = cell->payload + cell->payload_len;
- while (cp < end) {
- uint16_t len;
- if (end-cp == 1)
- goto err;
- len = ntohs(get_uint16(cp));
- cp += 2;
- if (end-cp < len)
- goto err;
- if (n_certs == 0) {
- id_cert = cp;
- id_cert_len = len;
- } else if (n_certs == 1) {
- conn_cert = id_cert;
- conn_cert_len = id_cert_len;
- id_cert = cp;
- id_cert_len = len;
- } else {
- goto err;
- }
- cp += len;
- ++n_certs;
- }
- /* Now we have 0, 1, or 2 certs. */
- if (n_certs == 0) {
- /* The other side is unauthenticated. */
- done = 1;
- } else {
- int r;
- r = tor_tls_verify_certs_v2(LOG_PROTOCOL_WARN, conn->tls,
- conn_cert, conn_cert_len,
- id_cert, id_cert_len,
- &conn->handshake_state->signing_key,
- (conn->handshake_state->started_here ?
- conn->handshake_state->server_cert_digest :
- conn->handshake_state->client_cert_digest),
- &conn->handshake_state->identity_key,
- conn->handshake_state->cert_id_digest);
- if (r < 0)
- goto err;
- if (r == 1) {
- done = 1;
- conn->handshake_state->authenticated = 1;
- }
- }
- conn->handshake_state->received_certs = 1;
- if (done) {
- if (connection_or_finish_or_handshake(conn) < 0)
- goto err;
- }
- if (! conn->handshake_state->signing_key)
- goto err;
- return;
- err:
- connection_mark_for_close(TO_CONN(conn));
- }
- #define LINK_AUTH_STRING "Tor initiator certificate verification"
- /** DOCDOC */
- static void
- command_process_link_auth_cell(cell_t *cell, or_connection_t *conn)
- {
- or_handshake_state_t *s;
- char hmac[DIGEST_LEN];
- uint16_t len;
- size_t sig_len;
- const char *sig;
- char *checked = NULL;
- int checked_len;
- tor_assert(conn);
- if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Received a LINK_AUTH cell on connection in the wrong state; "
- "dropping.");
- return;
- }
- s = conn->handshake_state;
- tor_assert(s);
- if (s->started_here) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR,
- "Got a LINK_AUTH cell from a server; closing the connection.");
- goto err;
- }
- if (!s->received_netinfo || !s->received_versions || !s->received_certs) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Got a LINK_AUTH cell too early; "
- "closing the connection");
- goto err;
- }
- len = ntohs(get_uint16(cell->payload));
- if (len < 2 || len > CELL_PAYLOAD_SIZE - 2) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad length field (%d) on LINK_AUTH cell;"
- " closing the connection", (int)len);
- goto err;
- }
- if (cell->payload[2] != 0x00) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Unrecognized LINK_AUTH signature "
- "version; closing the connection");
- goto err;
- }
- connection_or_compute_link_auth_hmac(conn, hmac);
- tor_assert(s->signing_key);
- sig = cell->payload+3;
- sig_len = len-1;
- checked = tor_malloc(crypto_pk_keysize(s->signing_key));
- checked_len = crypto_pk_public_checksig(s->signing_key,checked,sig,sig_len);
- if (checked_len < 0) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad signature on LINK_AUTH cell; "
- "closing the connection");
- goto err;
- }
- if (checked_len != DIGEST_LEN) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad length (%d) of signed material in "
- "LINK_AUTH cell; closing the connection", checked_len);
- goto err;
- }
- if (memcmp(checked, hmac, DIGEST_LEN) != 0) {
- log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad signed data in LINK_AUTH cell; "
- "closing the connection.");
- goto err;
- }
- s->authenticated = 1;
- if (connection_or_finish_or_handshake(conn)<0)
- goto err;
- tor_free(checked);
- return;
- err:
- tor_free(checked);
- connection_mark_for_close(TO_CONN(conn));
- }
- #endif
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