Commit c9b674d5 authored by teor's avatar teor
Browse files

relay: Protocol warn when a client gets an extend 

circuit_extend() may be called when a client receives an extend cell,
even if the relay module is disabled.

Log a protocol warning when the relay module is disabled.

Part of 33633.
parent f863954f

src/feature/relay/circuitbuild_relay.c

+7 −11
Original line number Original line Diff line number Diff line
@@ -39,11 +39,8 @@ 
#include "feature/relay/routermode.h"

#include "feature/relay/routermode.h"

#include "feature/relay/selftest.h"

#include "feature/relay/selftest.h"





/** Take the 'extend' <b>cell</b>, pull out addr/port plus the onion

/* Before replying to an extend cell, check the state of the circuit

 * skin and identity digest for the next hop. If we're already connected,

 * <b>circ</b>, and the configured tor mode.

 * pass the onion skin to the next hop using a create cell; otherwise

 * launch a new OR connection, and <b>circ</b> will notice when the

 * connection succeeds or fails.

 *

 *

 * Return -1 if we want to warn and tear down the circuit, else return 0.

 * Return -1 if we want to warn and tear down the circuit, else return 0.

 */

 */
@@ -56,6 +53,11 @@ circuit_extend(struct cell_t *cell, struct circuit_t *circ) 
  const char *msg = NULL;

  const char *msg = NULL;

  int should_launch = 0;

  int should_launch = 0;





  if (!server_mode(get_options())) {

    circuitbuild_warn_client_extend();

    return -1;

  }



  if (circ->n_chan) {

  if (circ->n_chan) {

    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,

    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,

           "n_chan already set. Bug/attack. Closing.");

           "n_chan already set. Bug/attack. Closing.");
@@ -67,12 +69,6 @@ circuit_extend(struct cell_t *cell, struct circuit_t *circ) 
    return -1;

    return -1;

  }

  }





  if (!server_mode(get_options())) {

    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,

           "Got an extend cell, but running as a client. Closing.");

    return -1;

  }



  relay_header_unpack(&rh, cell->payload);

  relay_header_unpack(&rh, cell->payload);





  if (extend_cell_parse(&ec, rh.command,

  if (extend_cell_parse(&ec, rh.command,

src/feature/relay/circuitbuild_relay.h

+12 −1
Original line number Original line Diff line number Diff line
@@ -13,6 +13,9 @@ 
#define TOR_FEATURE_RELAY_CIRCUITBUILD_RELAY_H

#define TOR_FEATURE_RELAY_CIRCUITBUILD_RELAY_H





#include "lib/cc/torint.h"

#include "lib/cc/torint.h"

#include "lib/log/log.h"



#include "app/config/config.h"





struct cell_t;

struct cell_t;

struct created_cell_t;

struct created_cell_t;
@@ -20,6 +23,14 @@ struct created_cell_t; 
struct circuit_t;

struct circuit_t;

struct or_circuit_t;

struct or_circuit_t;





/* Log a protocol warning about getting an extend cell on a client. */

static inline void

circuitbuild_warn_client_extend(void)

{

  log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,

         "Got an extend cell, but running as a client. Closing.");

}



#ifdef HAVE_MODULE_RELAY

#ifdef HAVE_MODULE_RELAY





int circuit_extend(struct cell_t *cell, struct circuit_t *circ);

int circuit_extend(struct cell_t *cell, struct circuit_t *circ);
@@ -36,7 +47,7 @@ circuit_extend(struct cell_t *cell, struct circuit_t *circ) 
{

{

  (void)cell;

  (void)cell;

  (void)circ;

  (void)circ;

  tor_assert_nonfatal_unreached();

  circuitbuild_warn_client_extend();

  return -1;

  return -1;

}

}