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      1 /* crypto/rsa/rsa_lib.c */
      2 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com)
      3  * All rights reserved.
      4  *
      5  * This package is an SSL implementation written
      6  * by Eric Young (eay (at) cryptsoft.com).
      7  * The implementation was written so as to conform with Netscapes SSL.
      8  *
      9  * This library is free for commercial and non-commercial use as long as
     10  * the following conditions are aheared to.  The following conditions
     11  * apply to all code found in this distribution, be it the RC4, RSA,
     12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
     13  * included with this distribution is covered by the same copyright terms
     14  * except that the holder is Tim Hudson (tjh (at) cryptsoft.com).
     15  *
     16  * Copyright remains Eric Young's, and as such any Copyright notices in
     17  * the code are not to be removed.
     18  * If this package is used in a product, Eric Young should be given attribution
     19  * as the author of the parts of the library used.
     20  * This can be in the form of a textual message at program startup or
     21  * in documentation (online or textual) provided with the package.
     22  *
     23  * Redistribution and use in source and binary forms, with or without
     24  * modification, are permitted provided that the following conditions
     25  * are met:
     26  * 1. Redistributions of source code must retain the copyright
     27  *    notice, this list of conditions and the following disclaimer.
     28  * 2. Redistributions in binary form must reproduce the above copyright
     29  *    notice, this list of conditions and the following disclaimer in the
     30  *    documentation and/or other materials provided with the distribution.
     31  * 3. All advertising materials mentioning features or use of this software
     32  *    must display the following acknowledgement:
     33  *    "This product includes cryptographic software written by
     34  *     Eric Young (eay (at) cryptsoft.com)"
     35  *    The word 'cryptographic' can be left out if the rouines from the library
     36  *    being used are not cryptographic related :-).
     37  * 4. If you include any Windows specific code (or a derivative thereof) from
     38  *    the apps directory (application code) you must include an acknowledgement:
     39  *    "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)"
     40  *
     41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
     42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     51  * SUCH DAMAGE.
     52  *
     53  * The licence and distribution terms for any publically available version or
     54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
     55  * copied and put under another distribution licence
     56  * [including the GNU Public Licence.]
     57  */
     58 
     59 #include <stdio.h>
     60 #include <openssl/crypto.h>
     61 #include "cryptlib.h"
     62 #include <openssl/lhash.h>
     63 #include <openssl/bn.h>
     64 #include <openssl/rsa.h>
     65 #include <openssl/rand.h>
     66 #ifndef OPENSSL_NO_ENGINE
     67 #include <openssl/engine.h>
     68 #endif
     69 
     70 int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
     71 	     RSA *rsa, int padding)
     72 	{
     73 	return(rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding));
     74 	}
     75 
     76 int RSA_private_encrypt(int flen, const unsigned char *from, unsigned char *to,
     77 	     RSA *rsa, int padding)
     78 	{
     79 #ifdef OPENSSL_FIPS
     80 	if(FIPS_mode() && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
     81 		{
     82 		RSAerr(RSA_F_RSA_PRIVATE_ENCRYPT, RSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE);
     83 		return 0;
     84 		}
     85 #endif
     86 	return(rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding));
     87 	}
     88 
     89 int RSA_private_decrypt(int flen, const unsigned char *from, unsigned char *to,
     90 	     RSA *rsa, int padding)
     91 	{
     92 	return(rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding));
     93 	}
     94 
     95 int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
     96 	     RSA *rsa, int padding)
     97 	{
     98 #ifdef OPENSSL_FIPS
     99 	if(FIPS_mode() && !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
    100 		{
    101 		RSAerr(RSA_F_RSA_PUBLIC_DECRYPT, RSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE);
    102 		return 0;
    103 		}
    104 #endif
    105 	return(rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding));
    106 	}
    107 
    108 int RSA_size(const RSA *r)
    109 	{
    110 	return(BN_num_bytes(r->n));
    111 	}
    112 
    113 void RSA_blinding_off(RSA *rsa)
    114 	{
    115 	if (rsa->blinding != NULL)
    116 		{
    117 		BN_BLINDING_free(rsa->blinding);
    118 		rsa->blinding=NULL;
    119 		}
    120 	rsa->flags &= ~RSA_FLAG_BLINDING;
    121 	rsa->flags |= RSA_FLAG_NO_BLINDING;
    122 	}
    123 
    124 int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
    125 	{
    126 	int ret=0;
    127 
    128 	if (rsa->blinding != NULL)
    129 		RSA_blinding_off(rsa);
    130 
    131 	rsa->blinding = RSA_setup_blinding(rsa, ctx);
    132 	if (rsa->blinding == NULL)
    133 		goto err;
    134 
    135 	rsa->flags |= RSA_FLAG_BLINDING;
    136 	rsa->flags &= ~RSA_FLAG_NO_BLINDING;
    137 	ret=1;
    138 err:
    139 	return(ret);
    140 	}
    141 
    142 static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
    143 	const BIGNUM *q, BN_CTX *ctx)
    144 {
    145 	BIGNUM *ret = NULL, *r0, *r1, *r2;
    146 
    147 	if (d == NULL || p == NULL || q == NULL)
    148 		return NULL;
    149 
    150 	BN_CTX_start(ctx);
    151 	r0 = BN_CTX_get(ctx);
    152 	r1 = BN_CTX_get(ctx);
    153 	r2 = BN_CTX_get(ctx);
    154 	if (r2 == NULL)
    155 		goto err;
    156 
    157 	if (!BN_sub(r1, p, BN_value_one())) goto err;
    158 	if (!BN_sub(r2, q, BN_value_one())) goto err;
    159 	if (!BN_mul(r0, r1, r2, ctx)) goto err;
    160 
    161 	ret = BN_mod_inverse(NULL, d, r0, ctx);
    162 err:
    163 	BN_CTX_end(ctx);
    164 	return ret;
    165 }
    166 
    167 BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
    168 {
    169 	BIGNUM local_n;
    170 	BIGNUM *e,*n;
    171 	BN_CTX *ctx;
    172 	BN_BLINDING *ret = NULL;
    173 
    174 	if (in_ctx == NULL)
    175 		{
    176 		if ((ctx = BN_CTX_new()) == NULL) return 0;
    177 		}
    178 	else
    179 		ctx = in_ctx;
    180 
    181 	BN_CTX_start(ctx);
    182 	e  = BN_CTX_get(ctx);
    183 	if (e == NULL)
    184 		{
    185 		RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
    186 		goto err;
    187 		}
    188 
    189 	if (rsa->e == NULL)
    190 		{
    191 		e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
    192 		if (e == NULL)
    193 			{
    194 			RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
    195 			goto err;
    196 			}
    197 		}
    198 	else
    199 		e = rsa->e;
    200 
    201 
    202 	if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL)
    203 		{
    204 		/* if PRNG is not properly seeded, resort to secret
    205 		 * exponent as unpredictable seed */
    206 		RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
    207 		}
    208 
    209 	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
    210 		{
    211 		/* Set BN_FLG_CONSTTIME flag */
    212 		n = &local_n;
    213 		BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
    214 		}
    215 	else
    216 		n = rsa->n;
    217 
    218 	ret = BN_BLINDING_create_param(NULL, e, n, ctx,
    219 			rsa->meth->bn_mod_exp, rsa->_method_mod_n);
    220 	if (ret == NULL)
    221 		{
    222 		RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
    223 		goto err;
    224 		}
    225 	BN_BLINDING_set_thread_id(ret, CRYPTO_thread_id());
    226 err:
    227 	BN_CTX_end(ctx);
    228 	if (in_ctx == NULL)
    229 		BN_CTX_free(ctx);
    230 	if(rsa->e == NULL)
    231 		BN_free(e);
    232 
    233 	return ret;
    234 }
    235