prop224: Add unit tests for INTRODUCE1 support

Signed-off-by: David Goulet <dgoulet@torproject.org>

5 files changed, 354 insertions, 12 deletions

diff --git a/src/or/hs_intropoint.c b/src/or/hs_intropoint.c
index b7dae7d3c4..25721e93c6 100644
--- a/src/or/hs_intropoint.c
+++ b/src/or/hs_intropoint.c
@@ -58,7 +58,7 @@ get_auth_key_from_cell(ed25519_public_key_t *auth_key_out,
   default:
     /* Getting here is really bad as it means we got a unknown cell type from
      * this file where every call has an hardcoded value. */
-    tor_assert(0);
+    tor_assert(0); /* LCOV_EXCL_LINE */
   }
   tor_assert(key_array);
   tor_assert(auth_key_len == sizeof(auth_key_out->pubkey));
@@ -371,7 +371,7 @@ send_introduce_ack_cell(or_circuit_t *circ, hs_intro_ack_status_t status)
 
 /* Validate a parsed INTRODUCE1 <b>cell</b>. Return 0 if valid or else a
  * negative value for an invalid cell that should be NACKed. */
-static int
+STATIC int
 validate_introduce1_parsed_cell(const hs_cell_introduce1_t *cell)
 {
   size_t legacy_key_id_len;
@@ -420,7 +420,7 @@ validate_introduce1_parsed_cell(const hs_cell_introduce1_t *cell)
  * everything went well, or -1 if an error occured. This function is in charge
  * of sending back an INTRODUCE_ACK cell and will close client_circ on error.
  */
-static int
+STATIC int
 handle_introduce1(or_circuit_t *client_circ, const uint8_t *request,
                   size_t request_len)
 {
@@ -476,10 +476,12 @@ handle_introduce1(or_circuit_t *client_circ, const uint8_t *request,
   if (relay_send_command_from_edge(CONTROL_CELL_ID, TO_CIRCUIT(service_circ),
                                    RELAY_COMMAND_INTRODUCE2,
                                    (char *) request, request_len, NULL)) {
+    /* LCOV_EXCL_START */
     log_warn(LD_REND, "Unable to send INTRODUCE2 cell to the service.");
     /* Inform the client that we can't relay the cell. */
     status = HS_INTRO_ACK_STATUS_CANT_RELAY;
     goto send_ack;
+    /* LCOV_EXCL_STOP */
   }
 
   /* Success! Send an INTRODUCE_ACK success status onto the client circuit. */
@@ -489,10 +491,12 @@ handle_introduce1(or_circuit_t *client_circ, const uint8_t *request,
  send_ack:
   /* Send the INTRODUCE_ACK cell to the client with a specific status. */
   if (send_introduce_ack_cell(client_circ, status) < 0) {
+    /* LCOV_EXCL_START */
     log_warn(LD_REND, "Unable to send an INTRODUCE ACK status %d to client.",
              status);
     /* Circuit has been closed on failure of transmission. */
     goto done;
+    /* LCOV_EXCL_STOP */
   }
   if (status != HS_INTRO_ACK_STATUS_SUCCESS) {
     /* We just sent a NACK that is a non success status code so close the
@@ -507,7 +511,7 @@ handle_introduce1(or_circuit_t *client_circ, const uint8_t *request,
 
 /* Identify if the encoded cell we just received is a legacy one or not. The
  * <b>request</b> should be at least DIGEST_LEN bytes long. */
-static int
+STATIC int
 introduce1_cell_is_legacy(const uint8_t *request)
 {
   tor_assert(request);
@@ -524,7 +528,7 @@ introduce1_cell_is_legacy(const uint8_t *request)
 
 /* Return true iff the circuit <b>circ</b> is suitable for receiving an
  * INTRODUCE1 cell. */
-static int
+STATIC int
 circuit_is_suitable_for_introduce1(const or_circuit_t *circ)
 {
   tor_assert(circ);
diff --git a/src/or/hs_intropoint.h b/src/or/hs_intropoint.h
index 08b3470bca..e6024a858f 100644
--- a/src/or/hs_intropoint.h
+++ b/src/or/hs_intropoint.h
@@ -37,6 +37,9 @@ int hs_intro_circuit_is_suitable_for_establish_intro(const or_circuit_t *circ);
 
 #ifdef HS_INTROPOINT_PRIVATE
 
+#include "hs/cell_establish_intro.h"
+#include "hs/cell_introduce1.h"
+
 STATIC int
 verify_establish_intro_cell(const hs_cell_establish_intro_t *out,
                             const uint8_t *circuit_key_material,
@@ -46,6 +49,12 @@ STATIC void
 get_auth_key_from_cell(ed25519_public_key_t *auth_key_out,
                        unsigned int cell_type, const void *cell);
 
+STATIC int introduce1_cell_is_legacy(const uint8_t *request);
+STATIC int handle_introduce1(or_circuit_t *client_circ,
+                             const uint8_t *request, size_t request_len);
+STATIC int validate_introduce1_parsed_cell(const hs_cell_introduce1_t *cell);
+STATIC int circuit_is_suitable_for_introduce1(const or_circuit_t *circ);
+
 #endif /* HS_INTROPOINT_PRIVATE */
 
 #endif /* TOR_HS_INTRO_H */
diff --git a/src/or/relay.c b/src/or/relay.c
index 8d48239e47..2e76a8ec36 100644
--- a/src/or/relay.c
+++ b/src/or/relay.c
@@ -595,11 +595,11 @@ relay_command_to_string(uint8_t command)
  * If you can't send the cell, mark the circuit for close and return -1. Else
  * return 0.
  */
-int
-relay_send_command_from_edge_(streamid_t stream_id, circuit_t *circ,
-                              uint8_t relay_command, const char *payload,
-                              size_t payload_len, crypt_path_t *cpath_layer,
-                              const char *filename, int lineno)
+MOCK_IMPL(int,
+relay_send_command_from_edge_,(streamid_t stream_id, circuit_t *circ,
+                               uint8_t relay_command, const char *payload,
+                               size_t payload_len, crypt_path_t *cpath_layer,
+                               const char *filename, int lineno))
 {
   cell_t cell;
   relay_header_t rh;
diff --git a/src/or/relay.h b/src/or/relay.h
index 26b594ece6..3acf3ee0e3 100644
--- a/src/or/relay.h
+++ b/src/or/relay.h
@@ -20,10 +20,11 @@ int circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
 
 void relay_header_pack(uint8_t *dest, const relay_header_t *src);
 void relay_header_unpack(relay_header_t *dest, const uint8_t *src);
-int relay_send_command_from_edge_(streamid_t stream_id, circuit_t *circ,
+MOCK_DECL(int,
+relay_send_command_from_edge_,(streamid_t stream_id, circuit_t *circ,
                                uint8_t relay_command, const char *payload,
                                size_t payload_len, crypt_path_t *cpath_layer,
-                               const char *filename, int lineno);
+                               const char *filename, int lineno));
 /* Indicates to relay_send_command_from_edge() that it is a control cell. */
 #define CONTROL_CELL_ID 0
 #define relay_send_command_from_edge(stream_id, circ, relay_command, payload, \
diff --git a/src/test/test_hs_intropoint.c b/src/test/test_hs_intropoint.c
index 7741cffa62..f8f4460e4a 100644
--- a/src/test/test_hs_intropoint.c
+++ b/src/test/test_hs_intropoint.c
@@ -13,11 +13,16 @@
 
 #include "test.h"
 #include "crypto.h"
+#include "log_test_helpers.h"
 
 #include "or.h"
 #include "ht.h"
 
+/* Trunnel. */
 #include "hs/cell_establish_intro.h"
+#include "hs/cell_introduce1.h"
+#include "hs/cell_common.h"
+
 #include "hs_service.h"
 #include "hs_circuitmap.h"
 #include "hs_intropoint.h"
@@ -25,6 +30,7 @@
 #include "circuitlist.h"
 #include "circuituse.h"
 #include "rendservice.h"
+#include "relay.h"
 
 /* Mock function to avoid networking in unittests */
 static int
@@ -34,6 +40,80 @@ mock_send_intro_established_cell(or_circuit_t *circ)
   return 0;
 }
 
+static int
+mock_relay_send_command_from_edge(streamid_t stream_id, circuit_t *circ,
+                                  uint8_t relay_command, const char *payload,
+                                  size_t payload_len, crypt_path_t *cpath_layer,
+                                  const char *filename, int lineno)
+{
+  (void) stream_id;
+  (void) circ;
+  (void) relay_command;
+  (void) payload;
+  (void) payload_len;
+  (void) cpath_layer;
+  (void) filename;
+  (void) lineno;
+  return 0;
+}
+
+static or_circuit_t *
+helper_create_intro_circuit(void)
+{
+  or_circuit_t *circ = or_circuit_new(0, NULL);
+  tt_assert(circ);
+  circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_OR);
+ done:
+  return circ;
+}
+
+static hs_cell_introduce1_t *
+helper_create_introduce1_cell(void)
+{
+  hs_cell_introduce1_t *cell = NULL;
+  ed25519_keypair_t auth_key_kp;
+
+  /* Generate the auth_key of the cell. */
+  if (ed25519_keypair_generate(&auth_key_kp, 0) < 0) {
+    goto err;
+  }
+
+  cell = hs_cell_introduce1_new();
+  tt_assert(cell);
+
+  /* Set the auth key. */
+  {
+    size_t auth_key_len = sizeof(auth_key_kp.pubkey);
+    hs_cell_introduce1_set_auth_key_type(cell,
+                                         HS_INTRO_AUTH_KEY_TYPE_ED25519);
+    hs_cell_introduce1_set_auth_key_len(cell, auth_key_len);
+    hs_cell_introduce1_setlen_auth_key(cell, auth_key_len);
+    uint8_t *auth_key_ptr = hs_cell_introduce1_getarray_auth_key(cell);
+    memcpy(auth_key_ptr, auth_key_kp.pubkey.pubkey, auth_key_len);
+  }
+
+  /* Set the cell extentions to none. */
+  {
+    cell_extension_t *ext = cell_extension_new();
+    cell_extension_set_num(ext, 0);
+    hs_cell_introduce1_set_extensions(cell, ext);
+  }
+
+  /* Set the encrypted section to some data. */
+  {
+    size_t enc_len = 128;
+    hs_cell_introduce1_setlen_encrypted(cell, enc_len);
+    uint8_t *enc_ptr = hs_cell_introduce1_getarray_encrypted(cell);
+    memset(enc_ptr, 'a', enc_len);
+  }
+
+  return cell;
+ err:
+ done:
+  hs_cell_introduce1_free(cell);
+  return NULL;
+}
+
 /* Try sending an ESTABLISH_INTRO cell on a circuit that is already an intro
  * point. Should fail. */
 static void
@@ -341,6 +421,242 @@ test_intro_point_registration(void *arg)
   UNMOCK(hs_intro_send_intro_established_cell);
 }
 
+static void
+test_introduce1_suitable_circuit(void *arg)
+{
+  int ret;
+  or_circuit_t *circ = NULL;
+
+  (void) arg;
+
+  /* Valid suitable circuit. */
+  {
+    circ = or_circuit_new(0, NULL);
+    circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_OR);
+    ret = circuit_is_suitable_for_introduce1(circ);
+    circuit_free(TO_CIRCUIT(circ));
+    tt_int_op(ret, OP_EQ, 1);
+  }
+
+  /* Test if the circuit purpose safeguard works correctly. */
+  {
+    circ = or_circuit_new(0, NULL);
+    circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_INTRO_POINT);
+    ret = circuit_is_suitable_for_introduce1(circ);
+    circuit_free(TO_CIRCUIT(circ));
+    tt_int_op(ret, OP_EQ, 0);
+  }
+
+  /* Test the non-edge circuit safeguard works correctly. */
+  {
+    circ = or_circuit_new(0, NULL);
+    circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_OR);
+    /* Bogus pointer, the check is against NULL on n_chan. */
+    circ->base_.n_chan = (channel_t *) circ;
+    ret = circuit_is_suitable_for_introduce1(circ);
+    circuit_free(TO_CIRCUIT(circ));
+    tt_int_op(ret, OP_EQ, 0);
+  }
+
+  /* Mangle the circuit a bit more so see if our only one INTRODUCE1 cell
+   * limit works correctly. */
+  {
+    circ = or_circuit_new(0, NULL);
+    circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_OR);
+    circ->already_received_introduce1 = 1;
+    ret = circuit_is_suitable_for_introduce1(circ);
+    circuit_free(TO_CIRCUIT(circ));
+    tt_int_op(ret, OP_EQ, 0);
+  }
+
+ done:
+  ;
+}
+
+static void
+test_introduce1_is_legacy(void *arg)
+{
+  int ret;
+  uint8_t request[256];
+
+  (void) arg;
+
+  /* For a cell to be considered legacy, according to the specification, the
+   * first 20 bytes MUST BE non-zero else it's a v3 cell. */
+  memset(request, 'a', DIGEST_LEN);
+  memset(request + DIGEST_LEN, 0, sizeof(request) - DIGEST_LEN);
+  ret = introduce1_cell_is_legacy(request);
+  tt_int_op(ret, OP_EQ, 1);
+
+  /* This is a NON legacy cell. */
+  memset(request, 0, DIGEST_LEN);
+  memset(request + DIGEST_LEN, 'a', sizeof(request) - DIGEST_LEN);
+  ret = introduce1_cell_is_legacy(request);
+  tt_int_op(ret, OP_EQ, 0);
+
+ done:
+  ;
+}
+
+static void
+test_introduce1_validation(void *arg)
+{
+  int ret;
+  hs_cell_introduce1_t *cell = NULL;
+
+  (void) arg;
+
+  /* Create our decoy cell that we'll modify as we go to test the validation
+   * function of that parsed cell. */
+  cell = helper_create_introduce1_cell();
+
+  /* It should NOT be a legacy cell which will trigger a BUG(). */
+  memset(cell->legacy_key_id, 'a', sizeof(cell->legacy_key_id));
+  tor_capture_bugs_(1);
+  ret = validate_introduce1_parsed_cell(cell);
+  tor_end_capture_bugs_();
+  tt_int_op(ret, OP_EQ, -1);
+  /* Reset legacy ID and make sure it's correct. */
+  memset(cell->legacy_key_id, 0, sizeof(cell->legacy_key_id));
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, 0);
+
+  /* Non existing auth key type. */
+  cell->auth_key_type = 42;
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, -1);
+  /* Reset is to correct value and make sure it's correct. */
+  cell->auth_key_type = HS_INTRO_AUTH_KEY_TYPE_ED25519;
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, 0);
+
+  /* Really bad key length. */
+  cell->auth_key_len = 0;
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, -1);
+  cell->auth_key_len = UINT16_MAX;
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, -1);
+  /* Correct size, let's try that. */
+  cell->auth_key_len = sizeof(ed25519_public_key_t);
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, 0);
+  /* Set an invalid size of the auth key buffer. */
+  hs_cell_introduce1_setlen_auth_key(cell, 3);
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, -1);
+  /* Reset auth key buffer and make sure it works. */
+  hs_cell_introduce1_setlen_auth_key(cell, sizeof(ed25519_public_key_t));
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, 0);
+
+  /* Empty encrypted section. */
+  hs_cell_introduce1_setlen_encrypted(cell, 0);
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, -1);
+  /* Reset it to some non zero bytes and validate. */
+  hs_cell_introduce1_setlen_encrypted(cell, 1);
+  ret = validate_introduce1_parsed_cell(cell);
+  tt_int_op(ret, OP_EQ, 0);
+
+ done:
+  hs_cell_introduce1_free(cell);
+}
+
+static void
+test_received_introduce1_handling(void *arg)
+{
+  int ret;
+  uint8_t *request = NULL, buf[128];
+  hs_cell_introduce1_t *cell = NULL;
+  or_circuit_t *circ = NULL;
+
+  (void) arg;
+
+  MOCK(relay_send_command_from_edge_, mock_relay_send_command_from_edge);
+
+  hs_circuitmap_init();
+
+  /* Too small request length. An INTRODUCE1 expect at the very least a
+   * DIGEST_LEN size. */
+  {
+    circ = helper_create_intro_circuit();
+    ret = hs_intro_received_introduce1(circ, buf, DIGEST_LEN - 1);
+    tt_int_op(ret, OP_EQ, -1);
+    circuit_free(TO_CIRCUIT(circ));
+  }
+
+  /* We have a unit test only for the suitability of a circuit to receive an
+   * INTRODUCE1 cell so from now on we'll only test the handling of a cell. */
+
+  /* Bad request. */
+  {
+    circ = helper_create_intro_circuit();
+    uint8_t test[2]; /* Too small request. */
+    ret = handle_introduce1(circ, test, sizeof(test));
+    tor_free(circ->p_chan);
+    circuit_free(TO_CIRCUIT(circ));
+    tt_int_op(ret, OP_EQ, -1);
+  }
+
+  /* Valid case. */
+  {
+    cell = helper_create_introduce1_cell();
+    size_t request_len = hs_cell_introduce1_encoded_len(cell);
+    tt_size_op(request_len, OP_GT, 0);
+    request = tor_malloc_zero(request_len);
+    ssize_t encoded_len = hs_cell_introduce1_encode(request, request_len, cell);
+    tt_size_op(encoded_len, OP_GT, 0);
+
+    circ = helper_create_intro_circuit();
+    or_circuit_t *service_circ = helper_create_intro_circuit();
+    circuit_change_purpose(TO_CIRCUIT(service_circ), CIRCUIT_PURPOSE_INTRO_POINT);
+    /* Register the circuit in the map for the auth key of the cell. */
+    ed25519_public_key_t auth_key;
+    const uint8_t *cell_auth_key =
+      hs_cell_introduce1_getconstarray_auth_key(cell);
+    memcpy(auth_key.pubkey, cell_auth_key, ED25519_PUBKEY_LEN);
+    hs_circuitmap_register_intro_circ_v3(service_circ, &auth_key);
+    ret = hs_intro_received_introduce1(circ, request, request_len);
+    circuit_free(TO_CIRCUIT(circ));
+    circuit_free(TO_CIRCUIT(service_circ));
+    tt_int_op(ret, OP_EQ, 0);
+  }
+
+  /* Valid legacy cell. */
+  {
+    tor_free(request);
+    hs_cell_introduce1_free(cell);
+    cell = helper_create_introduce1_cell();
+    uint8_t *legacy_key_id = hs_cell_introduce1_getarray_legacy_key_id(cell);
+    memset(legacy_key_id, 'a', DIGEST_LEN);
+    /* Add an arbitrary amount of data for the payload of a v2 cell. */
+    size_t request_len = hs_cell_introduce1_encoded_len(cell) + 256;
+    tt_size_op(request_len, OP_GT, 0);
+    request = tor_malloc_zero(request_len + 256);
+    ssize_t encoded_len = hs_cell_introduce1_encode(request, request_len, cell);
+    tt_size_op(encoded_len, OP_GT, 0);
+
+    circ = helper_create_intro_circuit();
+    or_circuit_t *service_circ = helper_create_intro_circuit();
+    circuit_change_purpose(TO_CIRCUIT(service_circ), CIRCUIT_PURPOSE_INTRO_POINT);
+    /* Register the circuit in the map for the auth key of the cell. */
+    uint8_t token[REND_TOKEN_LEN];
+    memcpy(token, legacy_key_id, sizeof(token));
+    hs_circuitmap_register_intro_circ_v2(service_circ, token);
+    ret = hs_intro_received_introduce1(circ, request, request_len);
+    circuit_free(TO_CIRCUIT(circ));
+    circuit_free(TO_CIRCUIT(service_circ));
+    tt_int_op(ret, OP_EQ, 0);
+  }
+
+ done:
+  hs_cell_introduce1_free(cell);
+  tor_free(request);
+  hs_circuitmap_free_all();
+  UNMOCK(relay_send_command_from_edge_);
+}
+
 struct testcase_t hs_intropoint_tests[] = {
   { "intro_point_registration",
     test_intro_point_registration, TT_FORK, NULL, NULL },
@@ -357,6 +673,18 @@ struct testcase_t hs_intropoint_tests[] = {
   { "receive_establish_intro_wrong_sig",
     test_establish_intro_wrong_sig, TT_FORK, NULL, NULL },
 
+  { "introduce1_suitable_circuit",
+    test_introduce1_suitable_circuit, TT_FORK, NULL, NULL },
+
+  { "introduce1_is_legacy",
+    test_introduce1_is_legacy, TT_FORK, NULL, NULL },
+
+  { "introduce1_validation",
+    test_introduce1_validation, TT_FORK, NULL, NULL },
+
+  { "received_introduce1_handling",
+    test_received_introduce1_handling, TT_FORK, NULL, NULL },
+
   END_OF_TESTCASES
 };