chore: checkpoint before Python removal

vendor/aws-lc-sys/aws-lc/crypto/rand_extra/deterministic.c

@@ -0,0 +1,42 @@
+// Copyright (c) 2016, Google Inc.
+// SPDX-License-Identifier: ISC
+
+#include <openssl/rand.h>
+
+#include "internal.h"
+
+#if defined(OPENSSL_RAND_DETERMINISTIC)
+
+#include <string.h>
+
+#include <openssl/chacha.h>
+
+#include "../internal.h"
+
+
+// g_num_calls is the number of calls to |CRYPTO_sysrand| that have occurred.
+//
+// This is intentionally not thread-safe. If the fuzzer mode is ever used in a
+// multi-threaded program, replace this with a thread-local. (A mutex would not
+// be deterministic.)
+static uint64_t g_num_calls = 0;
+static struct CRYPTO_STATIC_MUTEX g_num_calls_lock = CRYPTO_STATIC_MUTEX_INIT;
+
+void RAND_reset_for_fuzzing(void) { g_num_calls = 0; }
+
+void CRYPTO_sysrand(uint8_t *out, size_t requested) {
+  static const uint8_t kZeroKey[32];
+
+  CRYPTO_STATIC_MUTEX_lock_write(&g_num_calls_lock);
+  uint64_t num_calls = g_num_calls++;
+  CRYPTO_STATIC_MUTEX_unlock_write(&g_num_calls_lock);
+
+  uint8_t nonce[12];
+  OPENSSL_memset(nonce, 0, sizeof(nonce));
+  OPENSSL_memcpy(nonce, &num_calls, sizeof(num_calls));
+
+  OPENSSL_memset(out, 0, requested);
+  CRYPTO_chacha_20(out, out, requested, kZeroKey, nonce, 0);
+}
+
+#endif  // OPENSSL_RAND_DETERMINISTIC