openssl/crypto/rsa/rsa_crpt.c

/* 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.]
 */

#include <stdio.h>
#include <openssl/crypto.h>
#include "internal/cryptlib.h"
#include <openssl/lhash.h>
#include "internal/bn_int.h"
#include <openssl/rand.h>
#include "rsa_locl.h"

int RSA_bits(const RSA *r)
{
    return (BN_num_bits(r->n));
}

int RSA_size(const RSA *r)
{
    return (BN_num_bytes(r->n));
}

int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
                       RSA *rsa, int padding)
{
    return (rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding));
}

int RSA_private_encrypt(int flen, const unsigned char *from,
                        unsigned char *to, RSA *rsa, int padding)
{
    return (rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding));
}

int RSA_private_decrypt(int flen, const unsigned char *from,
                        unsigned char *to, RSA *rsa, int padding)
{
    return (rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding));
}

int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
                       RSA *rsa, int padding)
{
    return (rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding));
}

int RSA_flags(const RSA *r)
{
    return ((r == NULL) ? 0 : r->meth->flags);
}

void RSA_blinding_off(RSA *rsa)
{
    BN_BLINDING_free(rsa->blinding);
    rsa->blinding = NULL;
    rsa->flags &= ~RSA_FLAG_BLINDING;
    rsa->flags |= RSA_FLAG_NO_BLINDING;
}

int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
{
    int ret = 0;

    if (rsa->blinding != NULL)
        RSA_blinding_off(rsa);

    rsa->blinding = RSA_setup_blinding(rsa, ctx);
    if (rsa->blinding == NULL)
        goto err;

    rsa->flags |= RSA_FLAG_BLINDING;
    rsa->flags &= ~RSA_FLAG_NO_BLINDING;
    ret = 1;
 err:
    return (ret);
}

static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
                                  const BIGNUM *q, BN_CTX *ctx)
{
    BIGNUM *ret = NULL, *r0, *r1, *r2;

    if (d == NULL || p == NULL || q == NULL)
        return NULL;

    BN_CTX_start(ctx);
    r0 = BN_CTX_get(ctx);
    r1 = BN_CTX_get(ctx);
    r2 = BN_CTX_get(ctx);
    if (r2 == NULL)
        goto err;

    if (!BN_sub(r1, p, BN_value_one()))
        goto err;
    if (!BN_sub(r2, q, BN_value_one()))
        goto err;
    if (!BN_mul(r0, r1, r2, ctx))
        goto err;

    ret = BN_mod_inverse(NULL, d, r0, ctx);
 err:
    BN_CTX_end(ctx);
    return ret;
}

BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
{
    BIGNUM *e;
    BN_CTX *ctx;
    BN_BLINDING *ret = NULL;

    if (in_ctx == NULL) {
        if ((ctx = BN_CTX_new()) == NULL)
            return 0;
    } else
        ctx = in_ctx;

    BN_CTX_start(ctx);
    e = BN_CTX_get(ctx);
    if (e == NULL) {
        RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    if (rsa->e == NULL) {
        e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
        if (e == NULL) {
            RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
            goto err;
        }
    } else
        e = rsa->e;

    if ((RAND_status() == 0) && rsa->d != NULL
        && bn_get_words(rsa->d) != NULL) {
        /*
         * if PRNG is not properly seeded, resort to secret exponent as
         * unpredictable seed
         */
        RAND_add(bn_get_words(rsa->d), bn_get_dmax(rsa->d) * sizeof(BN_ULONG),
                 0.0);
    }

    {
        BIGNUM *local_n = NULL, *n;
        if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
            /* Set BN_FLG_CONSTTIME flag */
            local_n = n = BN_new();
            if (local_n == NULL) {
                RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
                goto err;
            }
            BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
        } else {
            n = rsa->n;
        }

        ret = BN_BLINDING_create_param(NULL, e, n, ctx, rsa->meth->bn_mod_exp,
                                       rsa->_method_mod_n);
        /* We MUST free local_n before any further use of rsa->n */
        BN_free(local_n);
    }
    if (ret == NULL) {
        RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
        goto err;
    }

    BN_BLINDING_set_current_thread(ret);

 err:
    BN_CTX_end(ctx);
    if (ctx != in_ctx)
        BN_CTX_free(ctx);
    if (e != rsa->e)
        BN_free(e);

    return ret;
}