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[tor-commits] [tor/maint-0.3.5] Merge branch 'maint-0.3.4' into maint-0.3.5



commit a8580a683696eb76f5f24fe36e7ea61f9c49db0a
Merge: f0408b844 761f1bf71
Author: Nick Mathewson <nickm@xxxxxxxxxxxxxx>
Date:   Fri Jan 18 12:25:08 2019 -0500

    Merge branch 'maint-0.3.4' into maint-0.3.5

 changes/bug29029           | 5 +++++
 src/feature/rend/rendmid.c | 6 +++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --cc src/feature/rend/rendmid.c
index 151604ada,000000000..fcfa5052c
mode 100644,000000..100644
--- a/src/feature/rend/rendmid.c
+++ b/src/feature/rend/rendmid.c
@@@ -1,370 -1,0 +1,370 @@@
 +/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 + * Copyright (c) 2007-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file rendmid.c
 + * \brief Implement introductions points and rendezvous points.
 + **/
 +
 +#include "core/or/or.h"
 +#include "core/or/channel.h"
 +#include "core/or/circuitlist.h"
 +#include "core/or/circuituse.h"
 +#include "app/config/config.h"
 +#include "lib/crypt_ops/crypto_cipher.h"
 +#include "core/or/dos.h"
 +#include "core/or/relay.h"
 +#include "feature/rend/rendmid.h"
 +#include "feature/stats/rephist.h"
 +#include "feature/hs/hs_circuitmap.h"
 +#include "feature/hs/hs_intropoint.h"
 +
 +#include "core/or/or_circuit_st.h"
 +
 +/** Respond to an ESTABLISH_INTRO cell by checking the signed data and
 + * setting the circuit's purpose and service pk digest.
 + */
 +int
 +rend_mid_establish_intro_legacy(or_circuit_t *circ, const uint8_t *request,
 +                                size_t request_len)
 +{
 +  crypto_pk_t *pk = NULL;
 +  char buf[DIGEST_LEN+9];
 +  char expected_digest[DIGEST_LEN];
 +  char pk_digest[DIGEST_LEN];
 +  size_t asn1len;
 +  or_circuit_t *c;
 +  char serviceid[REND_SERVICE_ID_LEN_BASE32+1];
 +  int reason = END_CIRC_REASON_INTERNAL;
 +
 +  log_info(LD_REND,
 +           "Received a legacy ESTABLISH_INTRO request on circuit %u",
 +           (unsigned) circ->p_circ_id);
 +
 +  if (!hs_intro_circuit_is_suitable_for_establish_intro(circ)) {
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    goto err;
 +  }
 +
 +  if (request_len < 2+DIGEST_LEN)
 +    goto truncated;
 +  /* First 2 bytes: length of asn1-encoded key. */
 +  asn1len = ntohs(get_uint16(request));
 +
 +  /* Next asn1len bytes: asn1-encoded key. */
 +  if (request_len < 2+DIGEST_LEN+asn1len)
 +    goto truncated;
 +  pk = crypto_pk_asn1_decode((char*)(request+2), asn1len);
 +  if (!pk) {
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    log_warn(LD_PROTOCOL, "Couldn't decode public key.");
 +    goto err;
 +  }
 +
 +  /* Next 20 bytes: Hash of rend_circ_nonce | "INTRODUCE" */
 +  memcpy(buf, circ->rend_circ_nonce, DIGEST_LEN);
 +  memcpy(buf+DIGEST_LEN, "INTRODUCE", 9);
 +  if (crypto_digest(expected_digest, buf, DIGEST_LEN+9) < 0) {
 +    log_warn(LD_BUG, "Internal error computing digest.");
 +    goto err;
 +  }
 +  if (tor_memneq(expected_digest, request+2+asn1len, DIGEST_LEN)) {
 +    log_warn(LD_PROTOCOL, "Hash of session info was not as expected.");
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    goto err;
 +  }
 +  /* Rest of body: signature of previous data */
 +  if (crypto_pk_public_checksig_digest(pk,
 +                                       (char*)request, 2+asn1len+DIGEST_LEN,
 +                                       (char*)(request+2+DIGEST_LEN+asn1len),
 +                                       request_len-(2+DIGEST_LEN+asn1len))<0) {
 +    log_warn(LD_PROTOCOL,
 +             "Incorrect signature on ESTABLISH_INTRO cell; rejecting.");
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    goto err;
 +  }
 +
 +  /* The request is valid.  First, compute the hash of the service's PK.*/
 +  if (crypto_pk_get_digest(pk, pk_digest)<0) {
 +    log_warn(LD_BUG, "Internal error: couldn't hash public key.");
 +    goto err;
 +  }
 +
 +  crypto_pk_free(pk); /* don't need it anymore */
 +  pk = NULL; /* so we don't free it again if err */
 +
 +  base32_encode(serviceid, REND_SERVICE_ID_LEN_BASE32+1,
 +                pk_digest, REND_SERVICE_ID_LEN);
 +
 +  /* Close any other intro circuits with the same pk. */
 +  c = NULL;
 +  while ((c = hs_circuitmap_get_intro_circ_v2_relay_side(
 +                                                (const uint8_t *)pk_digest))) {
 +    log_info(LD_REND, "Replacing old circuit for service %s",
 +             safe_str(serviceid));
 +    circuit_mark_for_close(TO_CIRCUIT(c), END_CIRC_REASON_FINISHED);
 +    /* Now it's marked, and it won't be returned next time. */
 +  }
 +
 +  /* Acknowledge the request. */
 +  if (hs_intro_send_intro_established_cell(circ) < 0) {
 +    log_info(LD_GENERAL, "Couldn't send INTRO_ESTABLISHED cell.");
 +    goto err_no_close;
 +  }
 +
 +  /* Now, set up this circuit. */
 +  circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_INTRO_POINT);
 +  hs_circuitmap_register_intro_circ_v2_relay_side(circ, (uint8_t *)pk_digest);
 +
 +  log_info(LD_REND,
 +           "Established introduction point on circuit %u for service %s",
 +           (unsigned) circ->p_circ_id, safe_str(serviceid));
 +
 +  return 0;
 + truncated:
 +  log_warn(LD_PROTOCOL, "Rejecting truncated ESTABLISH_INTRO cell.");
 +  reason = END_CIRC_REASON_TORPROTOCOL;
 + err:
 +  circuit_mark_for_close(TO_CIRCUIT(circ), reason);
 + err_no_close:
 +  if (pk) crypto_pk_free(pk);
 +  return -1;
 +}
 +
 +/** Process an INTRODUCE1 cell by finding the corresponding introduction
 + * circuit, and relaying the body of the INTRODUCE1 cell inside an
 + * INTRODUCE2 cell.
 + */
 +int
 +rend_mid_introduce_legacy(or_circuit_t *circ, const uint8_t *request,
 +                          size_t request_len)
 +{
 +  or_circuit_t *intro_circ;
 +  char serviceid[REND_SERVICE_ID_LEN_BASE32+1];
 +  char nak_body[1];
 +
 +  log_info(LD_REND, "Received an INTRODUCE1 request on circuit %u",
 +           (unsigned)circ->p_circ_id);
 +
 +  /* At this point, we know that the circuit is valid for an INTRODUCE1
 +   * because the validation has been made before calling this function. */
 +  tor_assert(circ->base_.purpose == CIRCUIT_PURPOSE_OR);
 +  tor_assert(!circ->base_.n_chan);
 +
 +  /* We could change this to MAX_HEX_NICKNAME_LEN now that 0.0.9.x is
 +   * obsolete; however, there isn't much reason to do so, and we're going
 +   * to revise this protocol anyway.
 +   */
 +  if (request_len < (DIGEST_LEN+(MAX_NICKNAME_LEN+1)+REND_COOKIE_LEN+
 +                     DH1024_KEY_LEN+CIPHER_KEY_LEN+
 +                     PKCS1_OAEP_PADDING_OVERHEAD)) {
 +    log_warn(LD_PROTOCOL, "Impossibly short INTRODUCE1 cell on circuit %u; "
 +             "responding with nack.",
 +             (unsigned)circ->p_circ_id);
 +    goto err;
 +  }
 +
 +  base32_encode(serviceid, REND_SERVICE_ID_LEN_BASE32+1,
 +                (char*)request, REND_SERVICE_ID_LEN);
 +
 +  /* The first 20 bytes are all we look at: they have a hash of the service's
 +   * PK. */
 +  intro_circ = hs_circuitmap_get_intro_circ_v2_relay_side(
 +                                                      (const uint8_t*)request);
 +  if (!intro_circ) {
 +    log_info(LD_REND,
 +             "No intro circ found for INTRODUCE1 cell (%s) from circuit %u; "
 +             "responding with nack.",
 +             safe_str(serviceid), (unsigned)circ->p_circ_id);
 +    goto err;
 +  }
 +
 +  log_info(LD_REND,
 +           "Sending introduction request for service %s "
 +           "from circ %u to circ %u",
 +           safe_str(serviceid), (unsigned)circ->p_circ_id,
 +           (unsigned)intro_circ->p_circ_id);
 +
 +  /* Great.  Now we just relay the cell down the circuit. */
 +  if (relay_send_command_from_edge(0, TO_CIRCUIT(intro_circ),
 +                                   RELAY_COMMAND_INTRODUCE2,
 +                                   (char*)request, request_len, NULL)) {
 +    log_warn(LD_GENERAL,
 +             "Unable to send INTRODUCE2 cell to Tor client.");
 +    /* Stop right now, the circuit has been closed. */
 +    return -1;
 +  }
 +  /* And send an ack down the client's circuit.  Empty body means succeeded. */
 +  if (relay_send_command_from_edge(0,TO_CIRCUIT(circ),
 +                                   RELAY_COMMAND_INTRODUCE_ACK,
 +                                   NULL,0,NULL)) {
 +    log_warn(LD_GENERAL, "Unable to send INTRODUCE_ACK cell to Tor client.");
 +    /* Stop right now, the circuit has been closed. */
 +    return -1;
 +  }
 +
 +  return 0;
 + err:
 +  /* Send the client a NACK */
 +  nak_body[0] = 1;
 +  if (relay_send_command_from_edge(0,TO_CIRCUIT(circ),
 +                                   RELAY_COMMAND_INTRODUCE_ACK,
 +                                   nak_body, 1, NULL)) {
 +    log_warn(LD_GENERAL, "Unable to send NAK to Tor client.");
 +  }
 +  return -1;
 +}
 +
 +/** Process an ESTABLISH_RENDEZVOUS cell by setting the circuit's purpose and
 + * rendezvous cookie.
 + */
 +int
 +rend_mid_establish_rendezvous(or_circuit_t *circ, const uint8_t *request,
 +                              size_t request_len)
 +{
 +  char hexid[9];
 +  int reason = END_CIRC_REASON_TORPROTOCOL;
 +
 +  log_info(LD_REND, "Received an ESTABLISH_RENDEZVOUS request on circuit %u",
 +           (unsigned)circ->p_circ_id);
 +
 +  if (circ->base_.purpose != CIRCUIT_PURPOSE_OR) {
-     log_warn(LD_PROTOCOL,
-              "Tried to establish rendezvous on non-OR circuit with purpose %s",
-              circuit_purpose_to_string(circ->base_.purpose));
++    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
++           "Tried to establish rendezvous on non-OR circuit with purpose %s",
++           circuit_purpose_to_string(circ->base_.purpose));
 +    goto err;
 +  }
 +
 +  /* Check if we are configured to accept established rendezvous cells from
 +   * client or in other words Tor2Web clients. */
 +  if (channel_is_client(circ->p_chan) &&
 +      dos_should_refuse_single_hop_client()) {
 +    /* Note it down for the heartbeat log purposes. */
 +    dos_note_refuse_single_hop_client();
 +    /* Silent drop so the client has to time out before moving on. */
 +    return 0;
 +  }
 +
 +  if (circ->base_.n_chan) {
 +    log_warn(LD_PROTOCOL,
 +             "Tried to establish rendezvous on non-edge circuit");
 +    goto err;
 +  }
 +
 +  if (request_len != REND_COOKIE_LEN) {
 +    log_fn(LOG_PROTOCOL_WARN,
 +           LD_PROTOCOL, "Invalid length on ESTABLISH_RENDEZVOUS.");
 +    goto err;
 +  }
 +
 +  if (hs_circuitmap_get_rend_circ_relay_side(request)) {
 +    log_warn(LD_PROTOCOL,
 +             "Duplicate rendezvous cookie in ESTABLISH_RENDEZVOUS.");
 +    goto err;
 +  }
 +
 +  /* Acknowledge the request. */
 +  if (relay_send_command_from_edge(0,TO_CIRCUIT(circ),
 +                                   RELAY_COMMAND_RENDEZVOUS_ESTABLISHED,
 +                                   "", 0, NULL)<0) {
 +    log_warn(LD_PROTOCOL, "Couldn't send RENDEZVOUS_ESTABLISHED cell.");
 +    /* Stop right now, the circuit has been closed. */
 +    return -1;
 +  }
 +
 +  circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_POINT_WAITING);
 +  hs_circuitmap_register_rend_circ_relay_side(circ, request);
 +
 +  base16_encode(hexid,9,(char*)request,4);
 +
 +  log_info(LD_REND,
 +           "Established rendezvous point on circuit %u for cookie %s",
 +           (unsigned)circ->p_circ_id, hexid);
 +
 +  return 0;
 + err:
 +  circuit_mark_for_close(TO_CIRCUIT(circ), reason);
 +  return -1;
 +}
 +
 +/** Process a RENDEZVOUS1 cell by looking up the correct rendezvous
 + * circuit by its relaying the cell's body in a RENDEZVOUS2 cell, and
 + * connecting the two circuits.
 + */
 +int
 +rend_mid_rendezvous(or_circuit_t *circ, const uint8_t *request,
 +                    size_t request_len)
 +{
 +  const or_options_t *options = get_options();
 +  or_circuit_t *rend_circ;
 +  char hexid[9];
 +  int reason = END_CIRC_REASON_INTERNAL;
 +
 +  if (circ->base_.purpose != CIRCUIT_PURPOSE_OR || circ->base_.n_chan) {
 +    log_info(LD_REND,
 +             "Tried to complete rendezvous on non-OR or non-edge circuit %u.",
 +             (unsigned)circ->p_circ_id);
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    goto err;
 +  }
 +
 +  if (request_len < REND_COOKIE_LEN) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +         "Rejecting RENDEZVOUS1 cell with bad length (%d) on circuit %u.",
 +         (int)request_len, (unsigned)circ->p_circ_id);
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    goto err;
 +  }
 +
 +  base16_encode(hexid, sizeof(hexid), (const char*)request, 4);
 +
 +  log_info(LD_REND,
 +           "Got request for rendezvous from circuit %u to cookie %s.",
 +           (unsigned)circ->p_circ_id, hexid);
 +
 +  rend_circ = hs_circuitmap_get_rend_circ_relay_side(request);
 +  if (!rend_circ) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +         "Rejecting RENDEZVOUS1 cell with unrecognized rendezvous cookie %s.",
 +         hexid);
 +    reason = END_CIRC_REASON_TORPROTOCOL;
 +    goto err;
 +  }
 +
 +  /* Statistics: Mark this circuit as an RP circuit so that we collect
 +     stats from it. */
 +  if (options->HiddenServiceStatistics) {
 +    circ->circuit_carries_hs_traffic_stats = 1;
 +  }
 +
 +  /* Send the RENDEZVOUS2 cell to the client. */
 +  if (relay_send_command_from_edge(0, TO_CIRCUIT(rend_circ),
 +                                   RELAY_COMMAND_RENDEZVOUS2,
 +                                   (char*)(request+REND_COOKIE_LEN),
 +                                   request_len-REND_COOKIE_LEN, NULL)) {
 +    log_warn(LD_GENERAL,
 +             "Unable to send RENDEZVOUS2 cell to client on circuit %u.",
 +             (unsigned)rend_circ->p_circ_id);
 +    /* Stop right now, the circuit has been closed. */
 +    return -1;
 +  }
 +
 +  /* Join the circuits. */
 +  log_info(LD_REND,
 +           "Completing rendezvous: circuit %u joins circuit %u (cookie %s)",
 +           (unsigned)circ->p_circ_id, (unsigned)rend_circ->p_circ_id, hexid);
 +
 +  circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_ESTABLISHED);
 +  circuit_change_purpose(TO_CIRCUIT(rend_circ),
 +                         CIRCUIT_PURPOSE_REND_ESTABLISHED);
 +  hs_circuitmap_remove_circuit(TO_CIRCUIT(circ));
 +
 +  rend_circ->rend_splice = circ;
 +  circ->rend_splice = rend_circ;
 +
 +  return 0;
 + err:
 +  circuit_mark_for_close(TO_CIRCUIT(circ), reason);
 +  return -1;
 +}

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