/* $OpenBSD: dsa_lib.c,v 1.35 2022/06/27 12:28:46 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.]

 */

/* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */

#include <stdio.h>

#include <openssl/opensslconf.h>

#include <openssl/asn1.h>

#include <openssl/bn.h>

#include <openssl/dsa.h>

#include <openssl/err.h>

#ifndef OPENSSL_NO_DH

#include <openssl/dh.h>

#endif

#ifndef OPENSSL_NO_ENGINE

#include <openssl/engine.h>

#endif

#include "dh_local.h"

#include "dsa_locl.h"

static const DSA_METHOD *default_DSA_method = NULL;

void

DSA_set_default_method(const DSA_METHOD *meth)

{

  default_DSA_method = meth;

}

const DSA_METHOD *

DSA_get_default_method(void)

{

  if (!default_DSA_method)

    default_DSA_method = DSA_OpenSSL();

  return default_DSA_method;

}

DSA *

DSA_new(void)

{

  return DSA_new_method(NULL);

}

int

DSA_set_method(DSA *dsa, const DSA_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 DSA_METHOD *mtmp;

        mtmp = dsa->meth;

        if (mtmp->finish)

    mtmp->finish(dsa);

#ifndef OPENSSL_NO_ENGINE

  ENGINE_finish(dsa->engine);

  dsa->engine = NULL;

#endif

        dsa->meth = meth;

        if (meth->init)

    meth->init(dsa);

        return 1;

}

DSA *

DSA_new_method(ENGINE *engine)

{

  DSA *ret;

  ret = malloc(sizeof(DSA));

  if (ret == NULL) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    return NULL;

  }

  ret->meth = DSA_get_default_method();

#ifndef OPENSSL_NO_ENGINE

  if (engine) {

    if (!ENGINE_init(engine)) {

      DSAerror(ERR_R_ENGINE_LIB);

      free(ret);

      return NULL;

    }

    ret->engine = engine;

  } else

    ret->engine = ENGINE_get_default_DSA();

  if (ret->engine) {

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

    if (ret->meth == NULL) {

      DSAerror(ERR_R_ENGINE_LIB);

      ENGINE_finish(ret->engine);

      free(ret);

      return NULL;

    }

  }

#endif

  ret->pad = 0;

  ret->version = 0;

  ret->p = NULL;

  ret->q = NULL;

  ret->g = NULL;

  ret->pub_key = NULL;

  ret->priv_key = NULL;

  ret->kinv = NULL;

  ret->r = NULL;

  ret->method_mont_p = NULL;

  ret->references = 1;

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

  CRYPTO_new_ex_data(CRYPTO_EX_INDEX_DSA, 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_DSA, ret, &ret->ex_data);

    free(ret);

    ret = NULL;

  }

  return ret;

}

void

DSA_free(DSA *r)

{

  int i;

  if (r == NULL)

    return;

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

  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_DSA, r, &r->ex_data);

  BN_clear_free(r->p);

  BN_clear_free(r->q);

  BN_clear_free(r->g);

  BN_clear_free(r->pub_key);

  BN_clear_free(r->priv_key);

  BN_clear_free(r->kinv);

  BN_clear_free(r->r);

  free(r);

}

int

DSA_up_ref(DSA *r)

{

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

  return i > 1 ? 1 : 0;

}

int

DSA_size(const DSA *r)

{

  int ret, i;

  ASN1_INTEGER bs;

  unsigned char buf[4]; /* 4 bytes looks really small.

           However, i2d_ASN1_INTEGER() will not look

           beyond the first byte, as long as the second

           parameter is NULL. */

  i = BN_num_bits(r->q);

  bs.length = (i + 7) / 8;

  bs.data = buf;

  bs.type = V_ASN1_INTEGER;

  /* If the top bit is set the asn1 encoding is 1 larger. */

  buf[0] = 0xff;

  i = i2d_ASN1_INTEGER(&bs, NULL);

  i += i; /* r and s */

  ret = ASN1_object_size(1, i, V_ASN1_SEQUENCE);

  return ret;

}

int

DSA_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_DSA, argl, argp,

      new_func, dup_func, free_func);

}

int

DSA_set_ex_data(DSA *d, int idx, void *arg)

{

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

}

void *

DSA_get_ex_data(DSA *d, int idx)

{

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

}

int

DSA_security_bits(const DSA *d)

{

  if (d->p == NULL || d->q == NULL)

    return -1;

  return BN_security_bits(BN_num_bits(d->p), BN_num_bits(d->q));

}

#ifndef OPENSSL_NO_DH

DH *

DSA_dup_DH(const DSA *r)

{

  /*

   * DSA has p, q, g, optional pub_key, optional priv_key.

   * DH has p, optional length, g, optional pub_key, optional priv_key,

   * optional q.

   */ 

  DH *ret = NULL;

  if (r == NULL)

    goto err;

  ret = DH_new();

  if (ret == NULL)

    goto err;

  if (r->p != NULL) 

    if ((ret->p = BN_dup(r->p)) == NULL)

      goto err;

  if (r->q != NULL) {

    ret->length = BN_num_bits(r->q);

    if ((ret->q = BN_dup(r->q)) == NULL)

      goto err;

  }

  if (r->g != NULL)

    if ((ret->g = BN_dup(r->g)) == NULL)

      goto err;

  if (r->pub_key != NULL)

    if ((ret->pub_key = BN_dup(r->pub_key)) == NULL)

      goto err;

  if (r->priv_key != NULL)

    if ((ret->priv_key = BN_dup(r->priv_key)) == NULL)

      goto err;

  return ret;

err:

  DH_free(ret);

  return NULL;

}

#endif

void

DSA_get0_pqg(const DSA *d, const BIGNUM **p, const BIGNUM **q, const BIGNUM **g)

{

  if (p != NULL)

    *p = d->p;

  if (q != NULL)

    *q = d->q;

  if (g != NULL)

    *g = d->g;

}

int

DSA_set0_pqg(DSA *d, BIGNUM *p, BIGNUM *q, BIGNUM *g)

{

  if ((d->p == NULL && p == NULL) || (d->q == NULL && q == NULL) ||

      (d->g == NULL && g == NULL))

    return 0;

  if (p != NULL) {

    BN_free(d->p);

    d->p = p;

  }

  if (q != NULL) {

    BN_free(d->q);

    d->q = q;

  }

  if (g != NULL) {

    BN_free(d->g);

    d->g = g;

  }

  return 1;

}

void

DSA_get0_key(const DSA *d, const BIGNUM **pub_key, const BIGNUM **priv_key)

{

  if (pub_key != NULL)

    *pub_key = d->pub_key;

  if (priv_key != NULL)

    *priv_key = d->priv_key;

}

int

DSA_set0_key(DSA *d, BIGNUM *pub_key, BIGNUM *priv_key)

{

  if (d->pub_key == NULL && pub_key == NULL)

    return 0;

  if (pub_key != NULL) {

    BN_free(d->pub_key);

    d->pub_key = pub_key;

  }

  if (priv_key != NULL) {

    BN_free(d->priv_key);

    d->priv_key = priv_key;

  }

  return 1;

}

const BIGNUM *

DSA_get0_p(const DSA *d)

{

  return d->p;

}

const BIGNUM *

DSA_get0_q(const DSA *d)

{

  return d->q;

}

const BIGNUM *

DSA_get0_g(const DSA *d)

{

  return d->g;

}

const BIGNUM *

DSA_get0_pub_key(const DSA *d)

{

  return d->pub_key;

}

const BIGNUM *

DSA_get0_priv_key(const DSA *d)

{

  return d->priv_key;

}

void

DSA_clear_flags(DSA *d, int flags)

{

  d->flags &= ~flags;

}

int

DSA_test_flags(const DSA *d, int flags)

{

  return d->flags & flags;

}

void

DSA_set_flags(DSA *d, int flags)

{

  d->flags |= flags;

}

ENGINE *

DSA_get0_engine(DSA *d)

{

  return d->engine;

}

int

DSA_bits(const DSA *dsa)

{

  return BN_num_bits(dsa->p);

}