Пример #1
0
/** Return a circuit that is open, is CIRCUIT_PURPOSE_C_GENERAL,
 * has a timestamp_dirty value of 0, has flags matching the CIRCLAUNCH_*
 * flags in <b>flags</b>, and if info is defined, does not already use info
 * as any of its hops; or NULL if no circuit fits this description.
 *
 * The <b>purpose</b> argument (currently ignored) refers to the purpose of
 * the circuit we want to create, not the purpose of the circuit we want to
 * cannibalize.
 *
 * If !CIRCLAUNCH_NEED_UPTIME, prefer returning non-uptime circuits.
 */
origin_circuit_t *
circuit_find_to_cannibalize(uint8_t purpose, extend_info_t *info,
                            int flags)
{
  circuit_t *_circ;
  origin_circuit_t *best=NULL;
  int need_uptime = (flags & CIRCLAUNCH_NEED_UPTIME) != 0;
  int need_capacity = (flags & CIRCLAUNCH_NEED_CAPACITY) != 0;
  int internal = (flags & CIRCLAUNCH_IS_INTERNAL) != 0;
  const or_options_t *options = get_options();

  /* Make sure we're not trying to create a onehop circ by
   * cannibalization. */
  tor_assert(!(flags & CIRCLAUNCH_ONEHOP_TUNNEL));

  log_debug(LD_CIRC,
            "Hunting for a circ to cannibalize: purpose %d, uptime %d, "
            "capacity %d, internal %d",
            purpose, need_uptime, need_capacity, internal);

  for (_circ=global_circuitlist; _circ; _circ = _circ->next) {
    if (CIRCUIT_IS_ORIGIN(_circ) &&
        _circ->state == CIRCUIT_STATE_OPEN &&
        !_circ->marked_for_close &&
        _circ->purpose == CIRCUIT_PURPOSE_C_GENERAL &&
        !_circ->timestamp_dirty) {
      origin_circuit_t *circ = TO_ORIGIN_CIRCUIT(_circ);
      if ((!need_uptime || circ->build_state->need_uptime) &&
          (!need_capacity || circ->build_state->need_capacity) &&
          (internal == circ->build_state->is_internal) &&
          circ->remaining_relay_early_cells &&
          circ->build_state->desired_path_len == DEFAULT_ROUTE_LEN &&
          !circ->build_state->onehop_tunnel &&
          !circ->isolation_values_set) {
        if (info) {
          /* need to make sure we don't duplicate hops */
          crypt_path_t *hop = circ->cpath;
          const node_t *ri1 = node_get_by_id(info->identity_digest);
          do {
            const node_t *ri2;
            if (tor_memeq(hop->extend_info->identity_digest,
                        info->identity_digest, DIGEST_LEN))
              goto next;
            if (ri1 &&
                (ri2 = node_get_by_id(hop->extend_info->identity_digest))
                && nodes_in_same_family(ri1, ri2))
              goto next;
            hop=hop->next;
          } while (hop!=circ->cpath);
        }
        if (options->ExcludeNodes) {
          /* Make sure no existing nodes in the circuit are excluded for
           * general use.  (This may be possible if StrictNodes is 0, and we
           * thought we needed to use an otherwise excluded node for, say, a
           * directory operation.) */
          crypt_path_t *hop = circ->cpath;
          do {
            if (routerset_contains_extendinfo(options->ExcludeNodes,
                                              hop->extend_info))
              goto next;
            hop = hop->next;
          } while (hop != circ->cpath);
        }
        if (!best || (best->build_state->need_uptime && !need_uptime))
          best = circ;
      next: ;
      }
    }
  }
  return best;
}
Пример #2
0
/** 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;
  const or_options_t *options = get_options();
  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(options) ||
      (!public_server_mode(options) && conn->is_outgoing)) {
    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
           "Received create cell (type %d) from %s:%d, but we're connected "
           "to it as 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_id_in_use_on_orconn(cell->circ_id, conn)) {
    const node_t *node = node_get_by_id(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 (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, conn);
  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) {
#define WARN_HANDOFF_FAILURE_INTERVAL (6*60*60)
      static ratelim_t handoff_warning =
        RATELIM_INIT(WARN_HANDOFF_FAILURE_INTERVAL);
      char *m;
      if ((m = rate_limit_log(&handoff_warning, approx_time()))) {
        log_warn(LD_GENERAL,"Failed to hand off onionskin. Closing.%s",m);
        tor_free(m);
      }
      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);

    /* Make sure we never try to use the OR connection on which we
     * received this cell to satisfy an EXTEND request,  */
    conn->is_connection_with_client = 1;

    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;
    }
  }
}
Пример #3
0
/** 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));
  }
}