rsa_chk.c

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/* 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
 *    [email protected].
 *
 * 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.
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 */

#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);
    }