prop289: Keep the digest bytes, not the object

The digest object is as large as the entire internal digest object's state,
which is often much larger than the actual set of bytes you're transmitting.

This commit makes it that we keep the digest itself which is 20 bytes.

Part of #26288

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

1 files changed, 11 insertions, 18 deletions

diff --git a/src/core/or/sendme.c b/src/core/or/sendme.c
index 0a7b1cbc02..3dcd9df08e 100644
--- a/src/core/or/sendme.c
+++ b/src/core/or/sendme.c
@@ -215,7 +215,7 @@ sendme_is_valid(const circuit_t *circ, const uint8_t *cell_payload,
  * Return the size in bytes of the encoded cell in payload. A negative value
  * is returned on encoding failure. */
 STATIC ssize_t
-build_cell_payload_v1(crypto_digest_t *cell_digest, uint8_t *payload)
+build_cell_payload_v1(const uint8_t *cell_digest, uint8_t *payload)
 {
   ssize_t len = -1;
   sendme_cell_t *cell = NULL;
@@ -231,9 +231,8 @@ build_cell_payload_v1(crypto_digest_t *cell_digest, uint8_t *payload)
   sendme_cell_set_data_len(cell, TRUNNEL_SENDME_V1_DIGEST_LEN);
 
   /* Copy the digest into the data payload. */
-  crypto_digest_get_digest(cell_digest,
-                           (char *) sendme_cell_getarray_data_v1_digest(cell),
-                           sendme_cell_get_data_len(cell));
+  memcpy(sendme_cell_getarray_data_v1_digest(cell), cell_digest,
+         sendme_cell_get_data_len(cell));
 
   /* Finally, encode the cell into the payload. */
   len = sendme_cell_encode(payload, RELAY_PAYLOAD_SIZE, cell);
@@ -249,7 +248,7 @@ build_cell_payload_v1(crypto_digest_t *cell_digest, uint8_t *payload)
  * because we failed to send the cell on it. */
 static int
 send_circuit_level_sendme(circuit_t *circ, crypt_path_t *layer_hint,
-                          crypto_digest_t *cell_digest)
+                          const uint8_t *cell_digest)
 {
   uint8_t emit_version;
   uint8_t payload[RELAY_PAYLOAD_SIZE];
@@ -340,7 +339,7 @@ sendme_connection_edge_consider_sending(edge_connection_t *conn)
 void
 sendme_circuit_consider_sending(circuit_t *circ, crypt_path_t *layer_hint)
 {
-  crypto_digest_t *digest;
+  const uint8_t *digest;
 
   while ((layer_hint ? layer_hint->deliver_window : circ->deliver_window) <=
           CIRCWINDOW_START - CIRCWINDOW_INCREMENT) {
@@ -539,7 +538,7 @@ sendme_note_stream_data_packaged(edge_connection_t *conn)
 void
 sendme_note_cell_digest(circuit_t *circ)
 {
-  uint8_t *digest;
+  const uint8_t *digest;
 
   tor_assert(circ);
 
@@ -555,16 +554,10 @@ sendme_note_cell_digest(circuit_t *circ)
     return;
   }
 
-  /* Only note the digest if we actually have the digest of the previous cell
-   * recorded. It should never happen in theory as we always record the last
-   * digest for the v1 SENDME. */
-  if (TO_OR_CIRCUIT(circ)->crypto.sendme_digest) {
-    digest = tor_malloc_zero(TRUNNEL_SENDME_V1_DIGEST_LEN);
-    crypto_digest_get_digest(TO_OR_CIRCUIT(circ)->crypto.sendme_digest,
-                             (char *) digest, TRUNNEL_SENDME_V1_DIGEST_LEN);
-    if (circ->sendme_last_digests == NULL) {
-      circ->sendme_last_digests = smartlist_new();
-    }
-    smartlist_add(circ->sendme_last_digests, digest);
+  /* Add the digest to the last seen list in the circuit. */
+  digest = TO_OR_CIRCUIT(circ)->crypto.sendme_digest;
+  if (circ->sendme_last_digests == NULL) {
+    circ->sendme_last_digests = smartlist_new();
   }
+  smartlist_add(circ->sendme_last_digests, tor_memdup(digest, DIGEST_LEN));
 }