test coverage on onion_fast: 0%->100%

src/or/onion_fast.c

@@ -59,8 +59,8 @@ fast_server_handshake(const uint8_t *key_in, /* DIGEST_LEN bytes */
   memcpy(tmp+DIGEST_LEN, handshake_reply_out, DIGEST_LEN);
   out_len = key_out_len+DIGEST_LEN;
   out = tor_malloc(out_len);
-  if (crypto_expand_key_material_TAP(tmp, sizeof(tmp), out, out_len)) {
-    goto done;
+  if (BUG(crypto_expand_key_material_TAP(tmp, sizeof(tmp), out, out_len))) {
+    goto done; // LCOV_EXCL_LINE
   }
   memcpy(handshake_reply_out+DIGEST_LEN, out, DIGEST_LEN);
   memcpy(key_out, out+DIGEST_LEN, key_out_len);
@@ -100,10 +100,12 @@ fast_client_handshake(const fast_handshake_state_t *handshake_state,
   memcpy(tmp+DIGEST_LEN, handshake_reply_out, DIGEST_LEN);
   out_len = key_out_len+DIGEST_LEN;
   out = tor_malloc(out_len);
-  if (crypto_expand_key_material_TAP(tmp, sizeof(tmp), out, out_len)) {
+  if (BUG(crypto_expand_key_material_TAP(tmp, sizeof(tmp), out, out_len))) {
+    /* LCOV_EXCL_START */
     if (msg_out)
       *msg_out = "Failed to expand key material";
     goto done;
+    /* LCOV_EXCL_STOP */
   }
   if (tor_memneq(out, handshake_reply_out+DIGEST_LEN, DIGEST_LEN)) {
     /* H(K) does *not* match. Something fishy. */

src/test/test.c

@@ -55,6 +55,7 @@ double fabs(double x);
 #include "memarea.h"
 #include "onion.h"
 #include "onion_ntor.h"
+#include "onion_fast.h"
 #include "onion_tap.h"
 #include "policies.h"
 #include "rephist.h"
@@ -266,6 +267,42 @@ test_ntor_handshake(void *arg)
   dimap_free(s_keymap, NULL);
 }
 
+static void
+test_fast_handshake(void *arg)
+{
+  /* tests for the obsolete "CREATE_FAST" handshake. */
+  (void) arg;
+  fast_handshake_state_t *state = NULL;
+  uint8_t client_handshake[CREATE_FAST_LEN];
+  uint8_t server_handshake[CREATED_FAST_LEN];
+  uint8_t s_keys[100], c_keys[100];
+
+  /* First, test an entire handshake. */
+  memset(client_handshake, 0, sizeof(client_handshake));
+  tt_int_op(0, OP_EQ, fast_onionskin_create(&state, client_handshake));
+  tt_assert(! tor_mem_is_zero((char*)client_handshake,
+                              sizeof(client_handshake)));
+
+  tt_int_op(0, OP_EQ,
+            fast_server_handshake(client_handshake, server_handshake,
+                                  s_keys, 100));
+  const char *msg = NULL;
+  tt_int_op(0, OP_EQ,
+            fast_client_handshake(state, server_handshake, c_keys, 100, &msg));
+  tt_ptr_op(msg, OP_EQ, NULL);
+  tt_mem_op(s_keys, OP_EQ, c_keys, 100);
+
+  /* Now test a failing handshake. */
+  server_handshake[0] ^= 3;
+  tt_int_op(-1, OP_EQ,
+            fast_client_handshake(state, server_handshake, c_keys, 100, &msg));
+  tt_str_op(msg, OP_EQ, "Digest DOES NOT MATCH on fast handshake. "
+            "Bug or attack.");
+
+ done:
+  fast_handshake_state_free(state);
+}
+
 /** Run unit tests for the onion queues. */
 static void
 test_onion_queues(void *arg)
@@ -1130,6 +1167,7 @@ static struct testcase_t test_array[] = {
   { "bad_onion_handshake", test_bad_onion_handshake, 0, NULL, NULL },
   ENT(onion_queues),
   { "ntor_handshake", test_ntor_handshake, 0, NULL, NULL },
+  { "fast_handshake", test_fast_handshake, 0, NULL, NULL },
   FORK(circuit_timeout),
   FORK(rend_fns),
   ENT(geoip),