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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_size(const RSA *r)
     71 	{
     72 	return(BN_num_bytes(r->n));
     73 	}
     74 
     75 int RSA_public_encrypt(int flen, const unsigned char *from, unsigned char *to,
     76 	     RSA *rsa, int padding)
     77 	{
     78 #ifdef OPENSSL_FIPS
     79 	if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
     80 			&& !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
     81 		{
     82 		RSAerr(RSA_F_RSA_PUBLIC_ENCRYPT, RSA_R_NON_FIPS_RSA_METHOD);
     83 		return -1;
     84 		}
     85 #endif
     86 	return(rsa->meth->rsa_pub_enc(flen, from, to, rsa, padding));
     87 	}
     88 
     89 int RSA_private_encrypt(int flen, const unsigned char *from, unsigned char *to,
     90 	     RSA *rsa, int padding)
     91 	{
     92 #ifdef OPENSSL_FIPS
     93 	if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
     94 			&& !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
     95 		{
     96 		RSAerr(RSA_F_RSA_PRIVATE_ENCRYPT, RSA_R_NON_FIPS_RSA_METHOD);
     97 		return -1;
     98 		}
     99 #endif
    100 	return(rsa->meth->rsa_priv_enc(flen, from, to, rsa, padding));
    101 	}
    102 
    103 int RSA_private_decrypt(int flen, const unsigned char *from, unsigned char *to,
    104 	     RSA *rsa, int padding)
    105 	{
    106 #ifdef OPENSSL_FIPS
    107 	if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
    108 			&& !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
    109 		{
    110 		RSAerr(RSA_F_RSA_PRIVATE_DECRYPT, RSA_R_NON_FIPS_RSA_METHOD);
    111 		return -1;
    112 		}
    113 #endif
    114 	return(rsa->meth->rsa_priv_dec(flen, from, to, rsa, padding));
    115 	}
    116 
    117 int RSA_public_decrypt(int flen, const unsigned char *from, unsigned char *to,
    118 	     RSA *rsa, int padding)
    119 	{
    120 #ifdef OPENSSL_FIPS
    121 	if (FIPS_mode() && !(rsa->meth->flags & RSA_FLAG_FIPS_METHOD)
    122 			&& !(rsa->flags & RSA_FLAG_NON_FIPS_ALLOW))
    123 		{
    124 		RSAerr(RSA_F_RSA_PUBLIC_DECRYPT, RSA_R_NON_FIPS_RSA_METHOD);
    125 		return -1;
    126 		}
    127 #endif
    128 	return(rsa->meth->rsa_pub_dec(flen, from, to, rsa, padding));
    129 	}
    130 
    131 int RSA_flags(const RSA *r)
    132 	{
    133 	return((r == NULL)?0:r->meth->flags);
    134 	}
    135 
    136 void RSA_blinding_off(RSA *rsa)
    137 	{
    138 	if (rsa->blinding != NULL)
    139 		{
    140 		BN_BLINDING_free(rsa->blinding);
    141 		rsa->blinding=NULL;
    142 		}
    143 	rsa->flags &= ~RSA_FLAG_BLINDING;
    144 	rsa->flags |= RSA_FLAG_NO_BLINDING;
    145 	}
    146 
    147 int RSA_blinding_on(RSA *rsa, BN_CTX *ctx)
    148 	{
    149 	int ret=0;
    150 
    151 	if (rsa->blinding != NULL)
    152 		RSA_blinding_off(rsa);
    153 
    154 	rsa->blinding = RSA_setup_blinding(rsa, ctx);
    155 	if (rsa->blinding == NULL)
    156 		goto err;
    157 
    158 	rsa->flags |= RSA_FLAG_BLINDING;
    159 	rsa->flags &= ~RSA_FLAG_NO_BLINDING;
    160 	ret=1;
    161 err:
    162 	return(ret);
    163 	}
    164 
    165 static BIGNUM *rsa_get_public_exp(const BIGNUM *d, const BIGNUM *p,
    166 	const BIGNUM *q, BN_CTX *ctx)
    167 {
    168 	BIGNUM *ret = NULL, *r0, *r1, *r2;
    169 
    170 	if (d == NULL || p == NULL || q == NULL)
    171 		return NULL;
    172 
    173 	BN_CTX_start(ctx);
    174 	r0 = BN_CTX_get(ctx);
    175 	r1 = BN_CTX_get(ctx);
    176 	r2 = BN_CTX_get(ctx);
    177 	if (r2 == NULL)
    178 		goto err;
    179 
    180 	if (!BN_sub(r1, p, BN_value_one())) goto err;
    181 	if (!BN_sub(r2, q, BN_value_one())) goto err;
    182 	if (!BN_mul(r0, r1, r2, ctx)) goto err;
    183 
    184 	ret = BN_mod_inverse(NULL, d, r0, ctx);
    185 err:
    186 	BN_CTX_end(ctx);
    187 	return ret;
    188 }
    189 
    190 BN_BLINDING *RSA_setup_blinding(RSA *rsa, BN_CTX *in_ctx)
    191 {
    192 	BIGNUM local_n;
    193 	BIGNUM *e,*n;
    194 	BN_CTX *ctx;
    195 	BN_BLINDING *ret = NULL;
    196 
    197 	if (in_ctx == NULL)
    198 		{
    199 		if ((ctx = BN_CTX_new()) == NULL) return 0;
    200 		}
    201 	else
    202 		ctx = in_ctx;
    203 
    204 	BN_CTX_start(ctx);
    205 	e  = BN_CTX_get(ctx);
    206 	if (e == NULL)
    207 		{
    208 		RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_MALLOC_FAILURE);
    209 		goto err;
    210 		}
    211 
    212 	if (rsa->e == NULL)
    213 		{
    214 		e = rsa_get_public_exp(rsa->d, rsa->p, rsa->q, ctx);
    215 		if (e == NULL)
    216 			{
    217 			RSAerr(RSA_F_RSA_SETUP_BLINDING, RSA_R_NO_PUBLIC_EXPONENT);
    218 			goto err;
    219 			}
    220 		}
    221 	else
    222 		e = rsa->e;
    223 
    224 
    225 	if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL)
    226 		{
    227 		/* if PRNG is not properly seeded, resort to secret
    228 		 * exponent as unpredictable seed */
    229 		RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
    230 		}
    231 
    232 	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
    233 		{
    234 		/* Set BN_FLG_CONSTTIME flag */
    235 		n = &local_n;
    236 		BN_with_flags(n, rsa->n, BN_FLG_CONSTTIME);
    237 		}
    238 	else
    239 		n = rsa->n;
    240 
    241 	ret = BN_BLINDING_create_param(NULL, e, n, ctx,
    242 			rsa->meth->bn_mod_exp, rsa->_method_mod_n);
    243 	if (ret == NULL)
    244 		{
    245 		RSAerr(RSA_F_RSA_SETUP_BLINDING, ERR_R_BN_LIB);
    246 		goto err;
    247 		}
    248 	CRYPTO_THREADID_current(BN_BLINDING_thread_id(ret));
    249 err:
    250 	BN_CTX_end(ctx);
    251 	if (in_ctx == NULL)
    252 		BN_CTX_free(ctx);
    253 	if(rsa->e == NULL)
    254 		BN_free(e);
    255 
    256 	return ret;
    257 }
    258