text: /* crypto/rsa/rsa_chk.c  */
  /* ====================================================================
   * 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>
  
  int RSA_check_key(const RSA *key)
  {
      BIGNUM *i, *j, *k, *l, *m;
      BN_CTX *ctx;
      int ret = 1;
  
      if (!key->p || !key->q || !key->n || !key->e || !key->d) {
          RSAerr(RSA_F_RSA_CHECK_KEY, 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;
          RSAerr(RSA_F_RSA_CHECK_KEY, ERR_R_MALLOC_FAILURE);
          goto err;
      }
  
      if (BN_is_one(key->e)) {
          ret = 0;
          RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_BAD_E_VALUE);
      }
      if (!BN_is_odd(key->e)) {
          ret = 0;
          RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_BAD_E_VALUE);
      }
  
      /* p prime? */
      if (BN_is_prime_ex(key->p, BN_prime_checks, NULL, NULL) != 1) {
          ret = 0;
          RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_P_NOT_PRIME);
      }
  
      /* q prime? */
      if (BN_is_prime_ex(key->q, BN_prime_checks, NULL, NULL) != 1) {
          ret = 0;
          RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_Q_NOT_PRIME);
      }
  
      /* n = p*q? */
      if (!BN_mul(i, key->p, key->q, ctx)) {
          ret = -1;
          goto err;
      }
      if (BN_cmp(i, key->n) != 0) {
          ret = 0;
          RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_N_DOES_NOT_EQUAL_P_Q);
      }
  
      /* d*e = 1  mod lcm(p-1,q-1)? */
      if (!BN_sub(i, key->p, BN_value_one())) {
          ret = -1;
          goto err;
      }
      if (!BN_sub(j, key->q, BN_value_one())) {
          ret = -1;
          goto err;
      }
  
      /* now compute k = lcm(i,j) */
      if (!BN_mul(l, i, j, ctx)) {
          ret = -1;
          goto err;
      }
      if (!BN_gcd(m, i, j, ctx)) {
          ret = -1;
          goto err;
      }
      if (!BN_div(k, NULL, l, m, ctx)) { /* remainder is 0 */
          ret = -1;
          goto err;
      }
      if (!BN_mod_mul(i, key->d, key->e, k, ctx)) {
          ret = -1;
          goto err;
      }
  
      if (!BN_is_one(i)) {
          ret = 0;
          RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_D_E_NOT_CONGRUENT_TO_1);
      }
  
      if (key->dmp1 != NULL && key->dmq1 != NULL && key->iqmp != NULL) {
          /* dmp1 = d mod (p-1)? */
          if (!BN_sub(i, key->p, BN_value_one())) {
              ret = -1;
              goto err;
          }
          if (!BN_mod(j, key->d, i, ctx)) {
              ret = -1;
              goto err;
          }
          if (BN_cmp(j, key->dmp1) != 0) {
              ret = 0;
              RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_DMP1_NOT_CONGRUENT_TO_D);
          }
  
          /* dmq1 = d mod (q-1)? */
          if (!BN_sub(i, key->q, BN_value_one())) {
              ret = -1;
              goto err;
          }
          if (!BN_mod(j, key->d, i, ctx)) {
              ret = -1;
              goto err;
          }
          if (BN_cmp(j, key->dmq1) != 0) {
              ret = 0;
              RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_DMQ1_NOT_CONGRUENT_TO_D);
          }
  
          /* iqmp = q^-1 mod p? */
          if (!BN_mod_inverse(i, key->q, key->p, ctx)) {
              ret = -1;
              goto err;
          }
          if (BN_cmp(i, key->iqmp) != 0) {
              ret = 0;
              RSAerr(RSA_F_RSA_CHECK_KEY, 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;
  }
  