rand.c

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/*
 * Copyright 2015-2018 Yubico AB
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#include "rand.h"
 
#ifdef _WIN32_BCRYPT
#include <windows.h>
#include <bcrypt.h>
#include <ntstatus.h>
#else
#include <openssl/rand.h>
#endif
 
bool rand_generate(uint8_t *buf, size_t cb_buf) {
 
#ifdef _WIN32_BCRYPT
  NTSTATUS status = STATUS_SUCCESS;
 
  BCRYPT_ALG_HANDLE hAlg = 0;
 
  if (!BCRYPT_SUCCESS(
        status =
          BCryptOpenAlgorithmProvider(&hAlg, BCRYPT_RNG_ALGORITHM, NULL, 0))) {
    return false;
  }
 
  status = BCryptGenRandom(hAlg, buf, (ULONG) cb_buf, 0);
  BCryptCloseAlgorithmProvider(hAlg, 0);
 
  return BCRYPT_SUCCESS(status);
 
#else
  return (1 == RAND_bytes(buf, cb_buf));
 
#endif
}