Commit ce477da8 authored by George Kadianakis's avatar George Kadianakis
Browse files

Ignore regular cells in padding circuits. 

Padding circuits were regular cells that got closed before their padding
machine could finish. This means that they can still receive regular cells from
their past life, but they have no way or reason to answer them anymore. Hence
let's ignore them before they even get to the proper subsystems.
parent 7a032c5e

scripts/maint/practracker/exceptions.txt

+3 −3
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ problem function-size /src/core/or/circuitlist.c:circuit_about_to_free() 120 
problem function-size /src/core/or/circuitlist.c:circuits_handle_oom() 117

problem function-size /src/core/or/circuitmux.c:circuitmux_set_policy() 109

problem function-size /src/core/or/circuitmux.c:circuitmux_attach_circuit() 113

problem file-size /src/core/or/circuitpadding.c 3006

problem file-size /src/core/or/circuitpadding.c 3043

problem function-size /src/core/or/circuitpadding.c:circpad_machine_schedule_padding() 107

problem function-size /src/core/or/circuitpadding_machines.c:circpad_machine_relay_hide_intro_circuits() 103

problem function-size /src/core/or/circuitpadding_machines.c:circpad_machine_client_hide_rend_circuits() 112
@@ -117,12 +117,12 @@ problem function-size /src/core/or/connection_or.c:connection_or_compute_authent 
problem file-size /src/core/or/policies.c 3249

problem function-size /src/core/or/policies.c:policy_summarize() 107

problem function-size /src/core/or/protover.c:protover_all_supported() 117

problem file-size /src/core/or/relay.c 3244

problem file-size /src/core/or/relay.c 3263

problem function-size /src/core/or/relay.c:circuit_receive_relay_cell() 126

problem function-size /src/core/or/relay.c:relay_send_command_from_edge_() 109

problem function-size /src/core/or/relay.c:connection_ap_process_end_not_open() 192

problem function-size /src/core/or/relay.c:connection_edge_process_relay_cell_not_open() 137

problem function-size /src/core/or/relay.c:connection_edge_process_relay_cell() 428

problem function-size /src/core/or/relay.c:handle_relay_cell_command() 369

problem function-size /src/core/or/relay.c:connection_edge_package_raw_inbuf() 128

problem function-size /src/core/or/relay.c:circuit_resume_edge_reading_helper() 146

problem function-size /src/core/or/scheduler_kist.c:kist_scheduler_run() 171

src/core/or/circuitpadding.c

+37 −0
Original line number Diff line number Diff line
@@ -1791,6 +1791,43 @@ circpad_cell_event_nonpadding_sent(circuit_t *on_circ) 
  } FOR_EACH_ACTIVE_CIRCUIT_MACHINE_END;

}



/** Check if this cell or circuit are related to circuit padding and handle

 *  them if so.  Return 0 if the cell was handled in this subsystem and does

 *  not need any other consideration, otherwise return 1.

 */

int

circpad_check_received_cell(cell_t *cell, circuit_t *circ,

                            crypt_path_t *layer_hint,

                            const relay_header_t *rh)

{

  unsigned domain = layer_hint?LD_APP:LD_EXIT;



  /* First handle the padding commands, since we want to ignore any other

   * commands if this circuit is padding-specific. */

  switch (rh->command) {

    case RELAY_COMMAND_DROP:

      /* Already examined in circpad_deliver_recognized_relay_cell_events */

      return 0;

    case RELAY_COMMAND_PADDING_NEGOTIATE:

      circpad_handle_padding_negotiate(circ, cell);

      return 0;

    case RELAY_COMMAND_PADDING_NEGOTIATED:

      if (circpad_handle_padding_negotiated(circ, cell, layer_hint) == 0)

        circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ), rh->length);

      return 0;

  }



  /* If this is a padding circuit we don't need to parse any other commands

   * than the padding ones. Just drop them to the floor. */

  if (circ->purpose == CIRCUIT_PURPOSE_C_CIRCUIT_PADDING) {

    log_info(domain, "Ignored cell (%d) that arrived in padding circuit.",

             rh->command);

    return 0;

  }



  return 1;

}



/**

 * A "non-padding" cell has been received by this endpoint. React

 * according to any padding state machines on the circuit.

src/core/or/circuitpadding.h

+4 −0
Original line number Diff line number Diff line
@@ -734,6 +734,10 @@ bool circpad_padding_negotiated(struct circuit_t *circ, 


circpad_purpose_mask_t circpad_circ_purpose_to_mask(uint8_t circ_purpose);



int circpad_check_received_cell(cell_t *cell, circuit_t *circ,

                                crypt_path_t *layer_hint,

                                const relay_header_t *rh);



MOCK_DECL(circpad_decision_t,

circpad_machine_schedule_padding,(circpad_machine_runtime_t *));

src/core/or/relay.c

+6 −19
Original line number Diff line number Diff line
@@ -1596,28 +1596,15 @@ handle_relay_command(cell_t *cell, circuit_t *circ, 


  tor_assert(rh);



  switch (rh->command) {

    case RELAY_COMMAND_DROP:

      /* Already examined in circpad_deliver_recognized_relay_cell_events */

      return 0;

    case RELAY_COMMAND_PADDING_NEGOTIATE:

      circpad_handle_padding_negotiate(circ, cell);

      return 0;

    case RELAY_COMMAND_PADDING_NEGOTIATED:

      if (circpad_handle_padding_negotiated(circ, cell, layer_hint) == 0)

        circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ), rh->length);

  /* First pass the cell to the circuit padding subsystem, in case it's a

   * padding cell or circuit that should be handled there. */

  if (circpad_check_received_cell(cell, circ, layer_hint, rh) == 0) {

    log_debug(domain, "Cell handled as circuit padding");

    return 0;

  }



  /* If this is a padding circuit we don't need to parse any other commands

   * than the padding ones. Just drop them to the floor. */

  if (circ->purpose == CIRCUIT_PURPOSE_C_CIRCUIT_PADDING) {

    log_info(domain, "Ignored cell (%d) that arrived in padding circuit.",

             rh.command);

    return 0;

  }



  switch (rh.command) {

  /* Now handle all the other commands */

  switch (rh->command) {

    case RELAY_COMMAND_BEGIN:

    case RELAY_COMMAND_BEGIN_DIR:

      if (layer_hint &&