prop224: Remove INTRODUCE2 legacy handling

Turns out that introduction points don't care about the INTRODUCE2 cell
format as long as the top field is LEGACY_KEY_ID as expected. So let's
use a single INTRODUCE format regardless of the introduction point being
legacy or not.

This also removes the polymorphic void* situation.

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

src/or/hs_cell.c

@@ -208,100 +208,35 @@ build_legacy_establish_intro(const char *circ_nonce, crypto_pk_t *enc_key,
   return cell_len;
 }
 
-/* Free the given cell pointer. If is_legacy_cell is set, cell_ptr is cast to
- * a rend_intro_cell_t else to a trn_cell_introduce1_t. */
-static void
-introduce2_free_cell(void *cell_ptr, unsigned int is_legacy_cell)
-{
-  if (cell_ptr == NULL) {
-    return;
-  }
-  if (is_legacy_cell) {
-    rend_intro_cell_t *legacy_cell = cell_ptr;
-    rend_service_free_intro(legacy_cell);
-  } else {
-    trn_cell_introduce1_free((trn_cell_introduce1_t *) cell_ptr);
-  }
-}
-
-/* Return the length of the encrypted section of the cell_ptr. If
- * is_legacy_cell is set, cell_ptr is cast to a rend_intro_cell_t else to a
- * trn_cell_introduce1_t. */
-static size_t
-get_introduce2_encrypted_section_len(const void *cell_ptr,
-                                     unsigned int is_legacy_cell)
-{
-  tor_assert(cell_ptr);
-  if (is_legacy_cell) {
-    return ((const rend_intro_cell_t *) cell_ptr)->ciphertext_len;
-  }
-  return trn_cell_introduce1_getlen_encrypted(
-                             (const trn_cell_introduce1_t *) cell_ptr);
-}
-
-/* Return the encrypted section pointer from the the cell_ptr. If
- * is_legacy_cell is set, cell_ptr is cast to a rend_intro_cell_t else to a
- * trn_cell_introduce1_t. */
-static const uint8_t *
-get_introduce2_encrypted_section(const void *cell_ptr,
-                                 unsigned int is_legacy_cell)
-{
-  tor_assert(cell_ptr);
-  if (is_legacy_cell) {
-    return ((const rend_intro_cell_t *) cell_ptr)->ciphertext;
-  }
-  return trn_cell_introduce1_getconstarray_encrypted(
-                             (const trn_cell_introduce1_t *) cell_ptr);
-}
-
 /* Parse an INTRODUCE2 cell from payload of size payload_len for the given
  * service and circuit which are used only for logging purposes. The resulting
- * parsed cell is put in cell_ptr_out. If is_legacy_cell is set, the type of
- * the returned cell is rend_intro_cell_t else trn_cell_introduce1_t.
+ * parsed cell is put in cell_ptr_out.
  *
  * Return 0 on success else a negative value and cell_ptr_out is untouched. */
 static int
 parse_introduce2_cell(const hs_service_t *service,
                       const origin_circuit_t *circ, const uint8_t *payload,
-                      size_t payload_len, unsigned int is_legacy_cell,
-                      void **cell_ptr_out)
+                      size_t payload_len,
+                      trn_cell_introduce1_t **cell_ptr_out)
 {
+  trn_cell_introduce1_t *cell = NULL;
+
   tor_assert(service);
   tor_assert(circ);
   tor_assert(payload);
   tor_assert(cell_ptr_out);
 
-  /* We parse the cell differently for legacy. */
-  if (is_legacy_cell) {
-    char *err_msg;
-    rend_intro_cell_t *legacy_cell = NULL;
-
-    legacy_cell = rend_service_begin_parse_intro(payload, payload_len, 2,
-                                                 &err_msg);
-    if (legacy_cell == NULL) {
-      log_info(LD_REND, "Unable to parse legacy INTRODUCE2 cell on "
-                        "circuit %u for service %s: %s",
-               TO_CIRCUIT(circ)->n_circ_id, err_msg,
-               safe_str_client(service->onion_address));
-      tor_free(err_msg);
-      goto err;
-    }
-    *cell_ptr_out = legacy_cell;
-  } else {
-    trn_cell_introduce1_t *cell = NULL;
-    /* Parse the cell so we can start cell validation. */
-    if (trn_cell_introduce1_parse(&cell, payload, payload_len) < 0) {
-      log_info(LD_PROTOCOL, "Unable to parse INTRODUCE2 cell on circuit %u "
-                            "for service %s",
-               TO_CIRCUIT(circ)->n_circ_id,
-               safe_str_client(service->onion_address));
-      goto err;
-    }
-    *cell_ptr_out = cell;
+  /* Parse the cell so we can start cell validation. */
+  if (trn_cell_introduce1_parse(&cell, payload, payload_len) < 0) {
+    log_info(LD_PROTOCOL, "Unable to parse INTRODUCE2 cell on circuit %u "
+                          "for service %s",
+             TO_CIRCUIT(circ)->n_circ_id,
+             safe_str_client(service->onion_address));
+    goto err;
   }
 
-  /* On success, we must have set the cell pointer. */
-  tor_assert(*cell_ptr_out);
+  /* Success. */
+  *cell_ptr_out = cell;
   return 0;
  err:
   return -1;
@@ -465,9 +400,9 @@ hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
   uint8_t *decrypted = NULL;
   size_t encrypted_section_len;
   const uint8_t *encrypted_section;
+  trn_cell_introduce1_t *cell = NULL;
   trn_cell_introduce_encrypted_t *enc_cell = NULL;
   hs_ntor_intro_cell_keys_t *intro_keys = NULL;
-  void *cell_ptr = NULL;
 
   tor_assert(data);
   tor_assert(circ);
@@ -475,7 +410,7 @@ hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
 
   /* Parse the cell into a decoded data structure pointed by cell_ptr. */
   if (parse_introduce2_cell(service, circ, data->payload, data->payload_len,
-                            data->is_legacy, &cell_ptr) < 0) {
+                            &cell) < 0) {
     goto done;
   }
 
@@ -484,10 +419,8 @@ hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
            TO_CIRCUIT(circ)->n_circ_id,
            safe_str_client(service->onion_address));
 
-  encrypted_section =
-    get_introduce2_encrypted_section(cell_ptr, data->is_legacy);
-  encrypted_section_len =
-    get_introduce2_encrypted_section_len(cell_ptr, data->is_legacy);
+  encrypted_section = trn_cell_introduce1_getconstarray_encrypted(cell);
+  encrypted_section_len = trn_cell_introduce1_getlen_encrypted(cell);
 
   /* Encrypted section must at least contain the CLIENT_PK and MAC which is
    * defined in section 3.3.2 of the specification. */
@@ -603,7 +536,7 @@ hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
   }
   tor_free(decrypted);
   trn_cell_introduce_encrypted_free(enc_cell);
-  introduce2_free_cell(cell_ptr, data->is_legacy);
+  trn_cell_introduce1_free(cell);
   return ret;
 }
 

src/or/hs_cell.h

@@ -34,8 +34,6 @@ typedef struct hs_cell_introduce2_data_t {
   const uint8_t *payload;
   /* Size of the payload of the received encoded cell. */
   size_t payload_len;
-  /* Is this a legacy introduction point? */
-  unsigned int is_legacy : 1;
 
   /*** Muttable Section. ***/
 

src/or/hs_circuit.c

@@ -945,7 +945,6 @@ hs_circ_handle_introduce2(const hs_service_t *service,
   data.payload = payload;
   data.payload_len = payload_len;
   data.link_specifiers = smartlist_new();
-  data.is_legacy = ip->base.is_only_legacy;
   data.replay_cache = ip->replay_cache;
 
   if (hs_cell_parse_introduce2(&data, circ, service) < 0) {