|
@@ -99,6 +99,10 @@ testing_enable_reproducible_rng(void)
|
|
|
* Replace our crypto_rand() prng with a variant that generates all of its
|
|
|
* output deterministically from a fixed seed. This variant is mainly useful
|
|
|
* for cases when we don't want coverage to change between runs.
|
|
|
+ *
|
|
|
+ * USAGE NOTE: Test correctness SHOULD NOT depend on the specific output of
|
|
|
+ * this "rng". If you need a specific output, use
|
|
|
+ * testing_enable_prefilled_rng() instead.
|
|
|
**/
|
|
|
void
|
|
|
testing_enable_deterministic_rng(void)
|
|
@@ -109,6 +113,59 @@ testing_enable_deterministic_rng(void)
|
|
|
enable_deterministic_rng_impl(quotation, sizeof(quotation));
|
|
|
}
|
|
|
|
|
|
+static uint8_t *prefilled_rng_buffer = NULL;
|
|
|
+static size_t prefilled_rng_buflen;
|
|
|
+static size_t prefilled_rng_idx;
|
|
|
+
|
|
|
+/**
|
|
|
+ * crypto_rand() replacement that returns canned data.
|
|
|
+ **/
|
|
|
+static void
|
|
|
+crypto_rand_prefilled(char *out, size_t n)
|
|
|
+{
|
|
|
+ tor_mutex_acquire(rng_mutex);
|
|
|
+ while (n) {
|
|
|
+ size_t n_to_copy = MIN(prefilled_rng_buflen - prefilled_rng_idx, n);
|
|
|
+ memcpy(out, prefilled_rng_buffer + prefilled_rng_idx, n_to_copy);
|
|
|
+ out += n_to_copy;
|
|
|
+ n -= n_to_copy;
|
|
|
+ prefilled_rng_idx += n_to_copy;
|
|
|
+
|
|
|
+ if (prefilled_rng_idx == prefilled_rng_buflen) {
|
|
|
+ prefilled_rng_idx = 0;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ tor_mutex_release(rng_mutex);
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * Replace our crypto_rand() prng with a variant that yields output
|
|
|
+ * from a buffer. If it reaches the end of the buffer, it starts over.
|
|
|
+ **/
|
|
|
+void
|
|
|
+testing_enable_prefilled_rng(const void *buffer, size_t buflen)
|
|
|
+{
|
|
|
+ tor_assert(buflen > 0);
|
|
|
+ rng_mutex = tor_mutex_new();
|
|
|
+
|
|
|
+ prefilled_rng_buffer = tor_memdup(buffer, buflen);
|
|
|
+ prefilled_rng_buflen = buflen;
|
|
|
+ prefilled_rng_idx = 0;
|
|
|
+
|
|
|
+ MOCK(crypto_rand, crypto_rand_prefilled);
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * Reset the position in the prefilled RNG buffer to the start.
|
|
|
+ */
|
|
|
+void
|
|
|
+testing_prefilled_rng_reset(void)
|
|
|
+{
|
|
|
+ tor_mutex_acquire(rng_mutex);
|
|
|
+ prefilled_rng_idx = 0;
|
|
|
+ tor_mutex_release(rng_mutex);
|
|
|
+}
|
|
|
+
|
|
|
/**
|
|
|
* Undo the overrides for our PRNG. To be used at the end of testing.
|
|
|
**/
|
|
@@ -116,6 +173,7 @@ void
|
|
|
testing_disable_rng_override(void)
|
|
|
{
|
|
|
crypto_xof_free(rng_xof);
|
|
|
+ tor_free(prefilled_rng_buffer);
|
|
|
UNMOCK(crypto_rand);
|
|
|
tor_mutex_free(rng_mutex);
|
|
|
}
|