// Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.

// Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved.

//

// 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

//

//     https://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 <openssl/ecdh.h>

#include <string.h>

#include <openssl/ec.h>

#include <openssl/ec_key.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include "../../internal.h"

#include "../bcm_interface.h"

#include "../ec/internal.h"

#include "../service_indicator/internal.h"

using namespace bssl;

int ECDH_compute_key_fips(uint8_t *out, size_t out_len, const EC_POINT *pub_key,

                          const EC_KEY *priv_key) {

  boringssl_ensure_ecc_self_test();

  if (FromOpaque(priv_key)->priv_key == nullptr) {

    OPENSSL_PUT_ERROR(ECDH, ECDH_R_NO_PRIVATE_VALUE);

    return 0;

  }

  const EC_SCALAR *const priv = &FromOpaque(priv_key)->priv_key->scalar;

  const EC_GROUP *const group = EC_KEY_get0_group(priv_key);

  if (EC_GROUP_cmp(group, pub_key->group, nullptr) != 0) {

    OPENSSL_PUT_ERROR(EC, EC_R_INCOMPATIBLE_OBJECTS);

    return 0;

  }

  EC_JACOBIAN shared_point;

  uint8_t buf[EC_MAX_BYTES];

  size_t buflen;

  if (!ec_point_mul_scalar(group, &shared_point, &pub_key->raw, priv) ||

      !ec_get_x_coordinate_as_bytes(group, buf, &buflen, sizeof(buf),

                                    &shared_point)) {

    OPENSSL_PUT_ERROR(ECDH, ECDH_R_POINT_ARITHMETIC_FAILURE);

    return 0;

  }

  FIPS_service_indicator_lock_state();

  SHA256_CTX ctx;

  SHA512_CTX ctx_512;

  switch (out_len) {

    case SHA224_DIGEST_LENGTH:

      BCM_sha224_init(&ctx);

      BCM_sha224_update(&ctx, buf, buflen);

      BCM_sha224_final(out, &ctx);

      break;

    case SHA256_DIGEST_LENGTH:

      BCM_sha256_init(&ctx);

      BCM_sha256_update(&ctx, buf, buflen);

      BCM_sha256_final(out, &ctx);

      break;

    case SHA384_DIGEST_LENGTH:

      BCM_sha384_init(&ctx_512);

      BCM_sha384_update(&ctx_512, buf, buflen);

      BCM_sha384_final(out, &ctx_512);

      break;

    case SHA512_DIGEST_LENGTH:

      BCM_sha512_init(&ctx_512);

      BCM_sha512_update(&ctx_512, buf, buflen);

      BCM_sha512_final(out, &ctx_512);

      break;

    default:

      OPENSSL_PUT_ERROR(ECDH, ECDH_R_UNKNOWN_DIGEST_LENGTH);

      FIPS_service_indicator_unlock_state();

      return 0;

  }

  FIPS_service_indicator_unlock_state();

  ECDH_verify_service_indicator(priv_key);

  return 1;

}