/* $OpenBSD: rsa_chk.c,v 1.16 2022/01/20 11:08:12 inoguchi Exp $ */

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

 * Copyright (c) 1999 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

 *    openssl-core@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.

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

 */

#include <openssl/bn.h>

#include <openssl/err.h>

#include <openssl/rsa.h>

#include "bn_lcl.h"

#include "rsa_locl.h"

int

RSA_check_key(const RSA *key)

{

  BIGNUM *i, *j, *k, *l, *m;

  BN_CTX *ctx;

  int r;

  int ret = 1;

  if (!key->p || !key->q || !key->n || !key->e || !key->d) {

    RSAerror(RSA_R_VALUE_MISSING);

    return 0;

  }

  i = BN_new();

  j = BN_new();

  k = BN_new();

  l = BN_new();

  m = BN_new();

  ctx = BN_CTX_new();

  if (i == NULL || j == NULL || k == NULL || l == NULL || m == NULL ||

      ctx == NULL) {

    ret = -1;

    RSAerror(ERR_R_MALLOC_FAILURE);

    goto err;

  }

  if (BN_is_one(key->e)) {

    ret = 0;

    RSAerror(RSA_R_BAD_E_VALUE);

  }

  if (!BN_is_odd(key->e)) {

    ret = 0;

    RSAerror(RSA_R_BAD_E_VALUE);

  }

  /* p prime? */

  r = BN_is_prime_ex(key->p, BN_prime_checks, NULL, NULL);

  if (r != 1) {

    ret = r;

    if (r != 0)

      goto err;

    RSAerror(RSA_R_P_NOT_PRIME);

  }

  /* q prime? */

  r = BN_is_prime_ex(key->q, BN_prime_checks, NULL, NULL);

  if (r != 1) {

    ret = r;

    if (r != 0)

      goto err;

    RSAerror(RSA_R_Q_NOT_PRIME);

  }

  /* n = p*q? */

  r = BN_mul(i, key->p, key->q, ctx);

  if (!r) {

    ret = -1;

    goto err;

  }

  if (BN_cmp(i, key->n) != 0) {

    ret = 0;

    RSAerror(RSA_R_N_DOES_NOT_EQUAL_P_Q);

  }

  /* d*e = 1  mod lcm(p-1,q-1)? */

  r = BN_sub(i, key->p, BN_value_one());

  if (!r) {

    ret = -1;

    goto err;

  }

  r = BN_sub(j, key->q, BN_value_one());

  if (!r) {

    ret = -1;

    goto err;

  }

  /* now compute k = lcm(i,j) */

  r = BN_mul(l, i, j, ctx);

  if (!r) {

    ret = -1;

    goto err;

  }

  r = BN_gcd_ct(m, i, j, ctx);

  if (!r) {

    ret = -1;

    goto err;

  }

  r = BN_div_ct(k, NULL, l, m, ctx); /* remainder is 0 */

  if (!r) {

    ret = -1;

    goto err;

  }

  r = BN_mod_mul(i, key->d, key->e, k, ctx);

  if (!r) {

    ret = -1;

    goto err;

  }

  if (!BN_is_one(i)) {

    ret = 0;

    RSAerror(RSA_R_D_E_NOT_CONGRUENT_TO_1);

  }

  if (key->dmp1 != NULL && key->dmq1 != NULL && key->iqmp != NULL) {

    /* dmp1 = d mod (p-1)? */

    r = BN_sub(i, key->p, BN_value_one());

    if (!r) {

      ret = -1;

      goto err;

    }

    r = BN_mod_ct(j, key->d, i, ctx);

    if (!r) {

      ret = -1;

      goto err;

    }

    if (BN_cmp(j, key->dmp1) != 0) {

      ret = 0;

      RSAerror(RSA_R_DMP1_NOT_CONGRUENT_TO_D);

    }

    /* dmq1 = d mod (q-1)? */

    r = BN_sub(i, key->q, BN_value_one());

    if (!r) {

      ret = -1;

      goto err;

    }

    r = BN_mod_ct(j, key->d, i, ctx);

    if (!r) {

      ret = -1;

      goto err;

    }

    if (BN_cmp(j, key->dmq1) != 0) {

      ret = 0;

      RSAerror(RSA_R_DMQ1_NOT_CONGRUENT_TO_D);

    }

    /* iqmp = q^-1 mod p? */

    if (BN_mod_inverse_ct(i, key->q, key->p, ctx) == NULL) {

      ret = -1;

      goto err;

    }

    if (BN_cmp(i, key->iqmp) != 0) {

      ret = 0;

      RSAerror(RSA_R_IQMP_NOT_INVERSE_OF_Q);

    }

  }

err:

  BN_free(i);

  BN_free(j);

  BN_free(k);

  BN_free(l);

  BN_free(m);

  BN_CTX_free(ctx);

  return (ret);

}