/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL

 * project 2000.

 */

/* ====================================================================

 * Copyright (c) 2000-2005 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    licensing@OpenSSL.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 * ====================================================================

 *

 * This product includes cryptographic software written by Eric Young

 * (eay@cryptsoft.com).  This product includes software written by Tim

 * Hudson (tjh@cryptsoft.com). */

#include <openssl/dh.h>

#include <assert.h>

#include <limits.h>

#include <openssl/bn.h>

#include <openssl/bytestring.h>

#include <openssl/err.h>

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

#include "../fipsmodule/dh/internal.h"

static int parse_integer(CBS *cbs, BIGNUM **out) {

  assert(*out == NULL);

  *out = BN_new();

  if (*out == NULL) {

    return 0;

  }

  return BN_parse_asn1_unsigned(cbs, *out);

}

static int marshal_integer(CBB *cbb, BIGNUM *bn) {

  if (bn == NULL) {

    // A DH object may be missing some components.

    OPENSSL_PUT_ERROR(DH, ERR_R_PASSED_NULL_PARAMETER);

    return 0;

  }

  return BN_marshal_asn1(cbb, bn);

}

DH *DH_parse_parameters(CBS *cbs) {

  DH *ret = DH_new();

  if (ret == NULL) {

    return NULL;

  }

  CBS child;

  if (!CBS_get_asn1(cbs, &child, CBS_ASN1_SEQUENCE) ||

      !parse_integer(&child, &ret->p) ||

      !parse_integer(&child, &ret->g)) {

    goto err;

  }

  uint64_t priv_length;

  if (CBS_len(&child) != 0) {

    if (!CBS_get_asn1_uint64(&child, &priv_length) ||

        priv_length > UINT_MAX) {

      goto err;

    }

    ret->priv_length = (unsigned)priv_length;

  }

  if (CBS_len(&child) != 0) {

    goto err;

  }

  if (!dh_check_params_fast(ret)) {

    goto err;

  }

  return ret;

err:

  OPENSSL_PUT_ERROR(DH, DH_R_DECODE_ERROR);

  DH_free(ret);

  return NULL;

}

int DH_marshal_parameters(CBB *cbb, const DH *dh) {

  CBB child;

  if (!CBB_add_asn1(cbb, &child, CBS_ASN1_SEQUENCE) ||

      !marshal_integer(&child, dh->p) ||

      !marshal_integer(&child, dh->g) ||

      (dh->priv_length != 0 &&

       !CBB_add_asn1_uint64(&child, dh->priv_length)) ||

      !CBB_flush(cbb)) {

    OPENSSL_PUT_ERROR(DH, DH_R_ENCODE_ERROR);

    return 0;

  }

  return 1;

}

DH *d2i_DHparams(DH **out, const uint8_t **inp, long len) {

  if (len < 0) {

    return NULL;

  }

  CBS cbs;

  CBS_init(&cbs, *inp, (size_t)len);

  DH *ret = DH_parse_parameters(&cbs);

  if (ret == NULL) {

    return NULL;

  }

  if (out != NULL) {

    DH_free(*out);

    *out = ret;

  }

  *inp = CBS_data(&cbs);

  return ret;

}

int i2d_DHparams(const DH *in, uint8_t **outp) {

  CBB cbb;

  if (!CBB_init(&cbb, 0) ||

      !DH_marshal_parameters(&cbb, in)) {

    CBB_cleanup(&cbb);

    return -1;

  }

  return CBB_finish_i2d(&cbb, outp);

}