/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*

 * This target fuzzes NSS mpi against openssl bignum.

 * It therefore requires openssl to be installed.

 */

#include "mpi_helper.h"

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

  // We require at least size 3 to get two integers from Data.

  if (size < 3) {

    return 0;

  }

  INIT_FOUR_NUMBERS

  auto modulus = get_modulus(data, size, ctx);

  // Compare with OpenSSL exp mod

  m1 = &std::get<1>(modulus);

  // The exponent b (B) can get really big. Make it smaller if necessary.

  if (MP_USED(&b) > 100) {

    size_t shift = (MP_USED(&b) - 100) * MP_DIGIT_BIT;

    mp_div_2d(&b, shift, &b, nullptr);

    BN_rshift(B, B, shift);

  }

  check_equal(A, &a, max_size);

  check_equal(B, &b, max_size);

  check_equal(std::get<0>(modulus), m1, 3 * max_size);

  assert(mp_exptmod(&a, &b, m1, &c) == MP_OKAY);

  (void)BN_mod_exp(C, A, B, std::get<0>(modulus), ctx);

  check_equal(C, &c, 2 * max_size);

  CLEANUP_AND_RETURN

}