/* $OpenBSD: dh_lib.c,v 1.37 2022/06/27 12:31:38 tb Exp $ */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 * 

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 * 

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 * 

 * 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 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 acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from 

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 * 

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS 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 AUTHOR OR 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.

 * 

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <limits.h>

#include <stdio.h>

#include <openssl/opensslconf.h>

#include <openssl/bn.h>

#include <openssl/dh.h>

#include <openssl/err.h>

#ifndef OPENSSL_NO_ENGINE

#include <openssl/engine.h>

#endif

#include "dh_local.h"

static const DH_METHOD *default_DH_method = NULL;

void

DH_set_default_method(const DH_METHOD *meth)

{

  default_DH_method = meth;

}

const DH_METHOD *

DH_get_default_method(void)

{

  if (!default_DH_method)

    default_DH_method = DH_OpenSSL();

  return default_DH_method;

}

int

DH_set_method(DH *dh, const DH_METHOD *meth)

{

  /*

   * NB: The caller is specifically setting a method, so it's not up to us

   * to deal with which ENGINE it comes from.

   */

        const DH_METHOD *mtmp;

        mtmp = dh->meth;

        if (mtmp->finish)

    mtmp->finish(dh);

#ifndef OPENSSL_NO_ENGINE

  ENGINE_finish(dh->engine);

  dh->engine = NULL;

#endif

        dh->meth = meth;

        if (meth->init)

    meth->init(dh);

        return 1;

}

DH *

DH_new(void)

{

  return DH_new_method(NULL);

}

DH *

DH_new_method(ENGINE *engine)

{

  DH *ret;

  ret = malloc(sizeof(DH));

  if (ret == NULL) {

    DHerror(ERR_R_MALLOC_FAILURE);

    return NULL;

  }

  ret->meth = DH_get_default_method();

#ifndef OPENSSL_NO_ENGINE

  if (engine) {

    if (!ENGINE_init(engine)) {

      DHerror(ERR_R_ENGINE_LIB);

      free(ret);

      return NULL;

    }

    ret->engine = engine;

  } else

    ret->engine = ENGINE_get_default_DH();

  if(ret->engine) {

    ret->meth = ENGINE_get_DH(ret->engine);

    if (ret->meth == NULL) {

      DHerror(ERR_R_ENGINE_LIB);

      ENGINE_finish(ret->engine);

      free(ret);

      return NULL;

    }

  }

#endif

  ret->pad = 0;

  ret->version = 0;

  ret->p = NULL;

  ret->g = NULL;

  ret->length = 0;

  ret->pub_key = NULL;

  ret->priv_key = NULL;

  ret->q = NULL;

  ret->j = NULL;

  ret->seed = NULL;

  ret->seedlen = 0;

  ret->counter = NULL;

  ret->method_mont_p=NULL;

  ret->references = 1;

  ret->flags = ret->meth->flags & ~DH_FLAG_NON_FIPS_ALLOW;

  CRYPTO_new_ex_data(CRYPTO_EX_INDEX_DH, ret, &ret->ex_data);

  if (ret->meth->init != NULL && !ret->meth->init(ret)) {

#ifndef OPENSSL_NO_ENGINE

    ENGINE_finish(ret->engine);

#endif

    CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DH, ret, &ret->ex_data);

    free(ret);

    ret = NULL;

  }

  return ret;

}

void

DH_free(DH *r)

{

  int i;

  if (r == NULL)

    return;

  i = CRYPTO_add(&r->references, -1, CRYPTO_LOCK_DH);

  if (i > 0)

    return;

  if (r->meth->finish)

    r->meth->finish(r);

#ifndef OPENSSL_NO_ENGINE

  ENGINE_finish(r->engine);

#endif

  CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DH, r, &r->ex_data);

  BN_clear_free(r->p);

  BN_clear_free(r->g);

  BN_clear_free(r->q);

  BN_clear_free(r->j);

  free(r->seed);

  BN_clear_free(r->counter);

  BN_clear_free(r->pub_key);

  BN_clear_free(r->priv_key);

  free(r);

}

int

DH_up_ref(DH *r)

{

  int i = CRYPTO_add(&r->references, 1, CRYPTO_LOCK_DH);

  return i > 1 ? 1 : 0;

}

int

DH_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,

    CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)

{

  return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_DH, argl, argp, new_func,

      dup_func, free_func);

}

int

DH_set_ex_data(DH *d, int idx, void *arg)

{

  return CRYPTO_set_ex_data(&d->ex_data, idx, arg);

}

void *

DH_get_ex_data(DH *d, int idx)

{

  return CRYPTO_get_ex_data(&d->ex_data, idx);

}

int

DH_size(const DH *dh)

{

  return BN_num_bytes(dh->p);

}

int

DH_bits(const DH *dh)

{

  return BN_num_bits(dh->p);

}

int

DH_security_bits(const DH *dh)

{

  int N = -1;

  if (dh->q != NULL)

    N = BN_num_bits(dh->q);

  else if (dh->length > 0)

    N = dh->length;

  return BN_security_bits(BN_num_bits(dh->p), N);

}

ENGINE *

DH_get0_engine(DH *dh)

{

  return dh->engine;

}

void

DH_get0_pqg(const DH *dh, const BIGNUM **p, const BIGNUM **q, const BIGNUM **g)

{

  if (p != NULL)

    *p = dh->p;

  if (q != NULL)

    *q = dh->q;

  if (g != NULL)

    *g = dh->g;

}

int

DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)

{

  if ((dh->p == NULL && p == NULL) || (dh->g == NULL && g == NULL))

    return 0;

  if (p != NULL) {

    BN_free(dh->p);

    dh->p = p;

  }

  if (q != NULL) {

    BN_free(dh->q);

    dh->q = q;

    dh->length = BN_num_bits(dh->q);

  }

  if (g != NULL) {

    BN_free(dh->g);

    dh->g = g;

  }

  return 1;

}

void

DH_get0_key(const DH *dh, const BIGNUM **pub_key, const BIGNUM **priv_key)

{

  if (pub_key != NULL)

    *pub_key = dh->pub_key;

  if (priv_key != NULL)

    *priv_key = dh->priv_key;

}

int

DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key)

{

  if (pub_key != NULL) {

    BN_free(dh->pub_key);

    dh->pub_key = pub_key;

  }

  if (priv_key != NULL) {

    BN_free(dh->priv_key);

    dh->priv_key = priv_key;

  }

  return 1;

}

const BIGNUM *

DH_get0_p(const DH *dh)

{

  return dh->p;

}

const BIGNUM *

DH_get0_q(const DH *dh)

{

  return dh->q;

}

const BIGNUM *

DH_get0_g(const DH *dh)

{

  return dh->g;

}

const BIGNUM *

DH_get0_priv_key(const DH *dh)

{

  return dh->priv_key;

}

const BIGNUM *

DH_get0_pub_key(const DH *dh)

{

  return dh->pub_key;

}

void

DH_clear_flags(DH *dh, int flags)

{

  dh->flags &= ~flags;

}

int

DH_test_flags(const DH *dh, int flags)

{

  return dh->flags & flags;

}

void

DH_set_flags(DH *dh, int flags)

{

  dh->flags |= flags;

}

long

DH_get_length(const DH *dh)

{

  return dh->length;

}

int

DH_set_length(DH *dh, long length)

{

  if (length < 0 || length > INT_MAX)

    return 0;

  dh->length = length;

  return 1;

}