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rsa_chk.c

/* crypto/rsa/rsa_chk.c  -*- Mode: C; c-file-style: "eay" -*- */
/* ====================================================================
 * 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 r;
      int ret=1;
      
      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;
            }
      
      /* p prime? */
      r = BN_is_prime_ex(key->p, BN_prime_checks, NULL, NULL);
      if (r != 1)
            {
            ret = r;
            if (r != 0)
                  goto err;
            RSAerr(RSA_F_RSA_CHECK_KEY, 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;
            RSAerr(RSA_F_RSA_CHECK_KEY, 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;
            RSAerr(RSA_F_RSA_CHECK_KEY, 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(m, i, j, ctx);
      if (!r) { ret = -1; goto err; }
      r = BN_div(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;
            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)? */
            r = BN_sub(i, key->p, BN_value_one());
            if (!r) { ret = -1; goto err; }

            r = BN_mod(j, key->d, i, ctx);
            if (!r) { 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)? */    
            r = BN_sub(i, key->q, BN_value_one());
            if (!r) { ret = -1; goto err; }
      
            r = BN_mod(j, key->d, i, ctx);
            if (!r) { 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:
      if (i != NULL) BN_free(i);
      if (j != NULL) BN_free(j);
      if (k != NULL) BN_free(k);
      if (l != NULL) BN_free(l);
      if (m != NULL) BN_free(m);
      if (ctx != NULL) BN_CTX_free(ctx);
      return (ret);
      }

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