crypto/rsa/rsa_eay.c

   1 /* crypto/rsa/rsa_eay.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@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@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@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@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 "cryptlib.h"
  61 #include <openssl/bn.h>
  62 #include <openssl/rsa.h>
  63 #include <openssl/rand.h>
  64 #ifndef OPENSSL_NO_ENGINE
  65 #include <openssl/engine.h>
  66 #endif
  67
  68 #ifndef RSA_NULL
  69
  70 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
  71                 unsigned char *to, RSA *rsa,int padding);
  72 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
  73                 unsigned char *to, RSA *rsa,int padding);
  74 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
  75                 unsigned char *to, RSA *rsa,int padding);
  76 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
  77                 unsigned char *to, RSA *rsa,int padding);
  78 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa);
  79 static int RSA_eay_init(RSA *rsa);
  80 static int RSA_eay_finish(RSA *rsa);
  81 static RSA_METHOD rsa_pkcs1_eay_meth={
  82         "Eric Young's PKCS#1 RSA",
  83         RSA_eay_public_encrypt,
  84         RSA_eay_public_decrypt, /* signature verification */
  85         RSA_eay_private_encrypt, /* signing */
  86         RSA_eay_private_decrypt,
  87         RSA_eay_mod_exp,
  88         BN_mod_exp_mont, /* XXX probably we should not use Montgomery if  e == 3 */
  89         RSA_eay_init,
  90         RSA_eay_finish,
  91         0, /* flags */
  92         NULL,
  93         0, /* rsa_sign */
  94         0, /* rsa_verify */
  95         NULL /* rsa_keygen */
  96         };
  97
  98 const RSA_METHOD *RSA_PKCS1_SSLeay(void)
  99         {
 100         return(&rsa_pkcs1_eay_meth);
 101         }
 102
 103 /* Static helper to reduce oodles of code duplication. As a slight
 104  * optimisation, the "MONT_HELPER() macro must be used as front-end to this
 105  * function, to prevent unnecessary function calls - there is an initial test
 106  * that is performed by the macro-generated code. */
 107 static int rsa_eay_mont_helper(BN_MONT_CTX **ptr, const BIGNUM *modulus, BN_CTX *ctx)
 108         {
 109         BN_MONT_CTX *bn_mont_ctx;
 110         if((bn_mont_ctx = BN_MONT_CTX_new()) == NULL)
 111                 return 0;
 112         if(!BN_MONT_CTX_set(bn_mont_ctx, modulus, ctx))
 113                 {
 114                 BN_MONT_CTX_free(bn_mont_ctx);
 115                 return 0;
 116                 }
 117         if (*ptr == NULL) /* other thread may have finished first */
 118                 {
 119                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 120                 if (*ptr == NULL) /* check again in the lock to stop races */
 121                         {
 122                         *ptr = bn_mont_ctx;
 123                         bn_mont_ctx = NULL;
 124                         }
 125                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 126                 }
 127         if (bn_mont_ctx)
 128                 BN_MONT_CTX_free(bn_mont_ctx);
 129         return 1;
 130         }
 131 /* Usage example;
 132  *    MONT_HELPER(rsa, bn_ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 133  */
 134 #define MONT_HELPER(rsa, ctx, m, pre_cond, err_instr) \
 135         if((pre_cond) && ((rsa)->_method_mod_##m == NULL) && \
 136                         !rsa_eay_mont_helper(&((rsa)->_method_mod_##m), \
 137                                 (rsa)->m, (ctx))) \
 138                 err_instr
 139
 140 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 141              unsigned char *to, RSA *rsa, int padding)
 142         {
 143         BIGNUM f,ret;
 144         int i,j,k,num=0,r= -1;
 145         unsigned char *buf=NULL;
 146         BN_CTX *ctx=NULL;
 147
 148         BN_init(&f);
 149         BN_init(&ret);
 150         if ((ctx=BN_CTX_new()) == NULL) goto err;
 151         num=BN_num_bytes(rsa->n);
 152         if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
 153                 {
 154                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
 155                 goto err;
 156                 }
 157
 158         switch (padding)
 159                 {
 160         case RSA_PKCS1_PADDING:
 161                 i=RSA_padding_add_PKCS1_type_2(buf,num,from,flen);
 162                 break;
 163 #ifndef OPENSSL_NO_SHA
 164         case RSA_PKCS1_OAEP_PADDING:
 165                 i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
 166                 break;
 167 #endif
 168         case RSA_SSLV23_PADDING:
 169                 i=RSA_padding_add_SSLv23(buf,num,from,flen);
 170                 break;
 171         case RSA_NO_PADDING:
 172                 i=RSA_padding_add_none(buf,num,from,flen);
 173                 break;
 174         default:
 175                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 176                 goto err;
 177                 }
 178         if (i <= 0) goto err;
 179
 180         if (BN_bin2bn(buf,num,&f) == NULL) goto err;
 181
 182         if (BN_ucmp(&f, rsa->n) >= 0)
 183                 {
 184                 /* usually the padding functions would catch this */
 185                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 186                 goto err;
 187                 }
 188
 189         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 190
 191         if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
 192                 rsa->_method_mod_n)) goto err;
 193
 194         /* put in leading 0 bytes if the number is less than the
 195          * length of the modulus */
 196         j=BN_num_bytes(&ret);
 197         i=BN_bn2bin(&ret,&(to[num-j]));
 198         for (k=0; k<(num-i); k++)
 199                 to[k]=0;
 200
 201         r=num;
 202 err:
 203         if (ctx != NULL) BN_CTX_free(ctx);
 204         BN_clear_free(&f);
 205         BN_clear_free(&ret);
 206         if (buf != NULL)
 207                 {
 208                 OPENSSL_cleanse(buf,num);
 209                 OPENSSL_free(buf);
 210                 }
 211         return(r);
 212         }
 213
 214 /* signing */
 215 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 216              unsigned char *to, RSA *rsa, int padding)
 217         {
 218         BIGNUM f,ret;
 219         int i,j,k,num=0,r= -1;
 220         unsigned char *buf=NULL;
 221         BN_CTX *ctx=NULL;
 222
 223         BN_init(&f);
 224         BN_init(&ret);
 225
 226         if ((ctx=BN_CTX_new()) == NULL) goto err;
 227         num=BN_num_bytes(rsa->n);
 228         if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
 229                 {
 230                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
 231                 goto err;
 232                 }
 233
 234         switch (padding)
 235                 {
 236         case RSA_PKCS1_PADDING:
 237                 i=RSA_padding_add_PKCS1_type_1(buf,num,from,flen);
 238                 break;
 239         case RSA_NO_PADDING:
 240                 i=RSA_padding_add_none(buf,num,from,flen);
 241                 break;
 242         case RSA_SSLV23_PADDING:
 243         default:
 244                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 245                 goto err;
 246                 }
 247         if (i <= 0) goto err;
 248
 249         if (BN_bin2bn(buf,num,&f) == NULL) goto err;
 250
 251         if (BN_ucmp(&f, rsa->n) >= 0)
 252                 {
 253                 /* usually the padding functions would catch this */
 254                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 255                 goto err;
 256                 }
 257
 258         if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
 259                 RSA_blinding_on(rsa,ctx);
 260         if (rsa->flags & RSA_FLAG_BLINDING)
 261                 if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) goto err;
 262
 263         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 264                 ((rsa->p != NULL) &&
 265                 (rsa->q != NULL) &&
 266                 (rsa->dmp1 != NULL) &&
 267                 (rsa->dmq1 != NULL) &&
 268                 (rsa->iqmp != NULL)) )
 269                 { if (!rsa->meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
 270         else
 271                 {
 272                 if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,NULL)) goto err;
 273                 }
 274
 275         if (rsa->flags & RSA_FLAG_BLINDING)
 276                 if (!BN_BLINDING_invert(&ret,rsa->blinding,ctx)) goto err;
 277
 278         /* put in leading 0 bytes if the number is less than the
 279          * length of the modulus */
 280         j=BN_num_bytes(&ret);
 281         i=BN_bn2bin(&ret,&(to[num-j]));
 282         for (k=0; k<(num-i); k++)
 283                 to[k]=0;
 284
 285         r=num;
 286 err:
 287         if (ctx != NULL) BN_CTX_free(ctx);
 288         BN_clear_free(&ret);
 289         BN_clear_free(&f);
 290         if (buf != NULL)
 291                 {
 292                 OPENSSL_cleanse(buf,num);
 293                 OPENSSL_free(buf);
 294                 }
 295         return(r);
 296         }
 297
 298 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 299              unsigned char *to, RSA *rsa, int padding)
 300         {
 301         BIGNUM f,ret;
 302         int j,num=0,r= -1;
 303         unsigned char *p;
 304         unsigned char *buf=NULL;
 305         BN_CTX *ctx=NULL;
 306
 307         BN_init(&f);
 308         BN_init(&ret);
 309         ctx=BN_CTX_new();
 310         if (ctx == NULL) goto err;
 311
 312         num=BN_num_bytes(rsa->n);
 313
 314         if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
 315                 {
 316                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
 317                 goto err;
 318                 }
 319
 320         /* This check was for equality but PGP does evil things
 321          * and chops off the top '0' bytes */
 322         if (flen > num)
 323                 {
 324                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 325                 goto err;
 326                 }
 327
 328         /* make data into a big number */
 329         if (BN_bin2bn(from,(int)flen,&f) == NULL) goto err;
 330
 331         if (BN_ucmp(&f, rsa->n) >= 0)
 332                 {
 333                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 334                 goto err;
 335                 }
 336
 337         if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
 338                 RSA_blinding_on(rsa,ctx);
 339         if (rsa->flags & RSA_FLAG_BLINDING)
 340                 if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) goto err;
 341
 342         /* do the decrypt */
 343         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 344                 ((rsa->p != NULL) &&
 345                 (rsa->q != NULL) &&
 346                 (rsa->dmp1 != NULL) &&
 347                 (rsa->dmq1 != NULL) &&
 348                 (rsa->iqmp != NULL)) )
 349                 { if (!rsa->meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
 350         else
 351                 {
 352                 if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,NULL))
 353                         goto err;
 354                 }
 355
 356         if (rsa->flags & RSA_FLAG_BLINDING)
 357                 if (!BN_BLINDING_invert(&ret,rsa->blinding,ctx)) goto err;
 358
 359         p=buf;
 360         j=BN_bn2bin(&ret,p); /* j is only used with no-padding mode */
 361
 362         switch (padding)
 363                 {
 364         case RSA_PKCS1_PADDING:
 365                 r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
 366                 break;
 367 #ifndef OPENSSL_NO_SHA
 368         case RSA_PKCS1_OAEP_PADDING:
 369                 r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
 370                 break;
 371 #endif
 372         case RSA_SSLV23_PADDING:
 373                 r=RSA_padding_check_SSLv23(to,num,buf,j,num);
 374                 break;
 375         case RSA_NO_PADDING:
 376                 r=RSA_padding_check_none(to,num,buf,j,num);
 377                 break;
 378         default:
 379                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 380                 goto err;
 381                 }
 382         if (r < 0)
 383                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 384
 385 err:
 386         if (ctx != NULL) BN_CTX_free(ctx);
 387         BN_clear_free(&f);
 388         BN_clear_free(&ret);
 389         if (buf != NULL)
 390                 {
 391                 OPENSSL_cleanse(buf,num);
 392                 OPENSSL_free(buf);
 393                 }
 394         return(r);
 395         }
 396
 397 /* signature verification */
 398 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 399              unsigned char *to, RSA *rsa, int padding)
 400         {
 401         BIGNUM f,ret;
 402         int i,num=0,r= -1;
 403         unsigned char *p;
 404         unsigned char *buf=NULL;
 405         BN_CTX *ctx=NULL;
 406
 407         BN_init(&f);
 408         BN_init(&ret);
 409         ctx=BN_CTX_new();
 410         if (ctx == NULL) goto err;
 411
 412         num=BN_num_bytes(rsa->n);
 413         buf=(unsigned char *)OPENSSL_malloc(num);
 414         if (buf == NULL)
 415                 {
 416                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
 417                 goto err;
 418                 }
 419
 420         /* This check was for equality but PGP does evil things
 421          * and chops off the top '0' bytes */
 422         if (flen > num)
 423                 {
 424                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 425                 goto err;
 426                 }
 427
 428         if (BN_bin2bn(from,flen,&f) == NULL) goto err;
 429
 430         if (BN_ucmp(&f, rsa->n) >= 0)
 431                 {
 432                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 433                 goto err;
 434                 }
 435
 436         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 437
 438         if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
 439                 rsa->_method_mod_n)) goto err;
 440
 441         p=buf;
 442         i=BN_bn2bin(&ret,p);
 443
 444         switch (padding)
 445                 {
 446         case RSA_PKCS1_PADDING:
 447                 r=RSA_padding_check_PKCS1_type_1(to,num,buf,i,num);
 448                 break;
 449         case RSA_NO_PADDING:
 450                 r=RSA_padding_check_none(to,num,buf,i,num);
 451                 break;
 452         default:
 453                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 454                 goto err;
 455                 }
 456         if (r < 0)
 457                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 458
 459 err:
 460         if (ctx != NULL) BN_CTX_free(ctx);
 461         BN_clear_free(&f);
 462         BN_clear_free(&ret);
 463         if (buf != NULL)
 464                 {
 465                 OPENSSL_cleanse(buf,num);
 466                 OPENSSL_free(buf);
 467                 }
 468         return(r);
 469         }
 470
 471 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
 472         {
 473         BIGNUM r1,m1,vrfy;
 474         int ret=0;
 475         BN_CTX *ctx;
 476
 477         BN_init(&m1);
 478         BN_init(&r1);
 479         BN_init(&vrfy);
 480         if ((ctx=BN_CTX_new()) == NULL) goto err;
 481
 482         MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 483         MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 484         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 485
 486         if (!BN_mod(&r1,I,rsa->q,ctx)) goto err;
 487         if (!rsa->meth->bn_mod_exp(&m1,&r1,rsa->dmq1,rsa->q,ctx,
 488                 rsa->_method_mod_q)) goto err;
 489
 490         if (!BN_mod(&r1,I,rsa->p,ctx)) goto err;
 491         if (!rsa->meth->bn_mod_exp(r0,&r1,rsa->dmp1,rsa->p,ctx,
 492                 rsa->_method_mod_p)) goto err;
 493
 494         if (!BN_sub(r0,r0,&m1)) goto err;
 495         /* This will help stop the size of r0 increasing, which does
 496          * affect the multiply if it optimised for a power of 2 size */
 497         if (BN_get_sign(r0))
 498                 if (!BN_add(r0,r0,rsa->p)) goto err;
 499
 500         if (!BN_mul(&r1,r0,rsa->iqmp,ctx)) goto err;
 501         if (!BN_mod(r0,&r1,rsa->p,ctx)) goto err;
 502         /* If p < q it is occasionally possible for the correction of
 503          * adding 'p' if r0 is negative above to leave the result still
 504          * negative. This can break the private key operations: the following
 505          * second correction should *always* correct this rare occurrence.
 506          * This will *never* happen with OpenSSL generated keys because
 507          * they ensure p > q [steve]
 508          */
 509         if (BN_get_sign(r0))
 510                 if (!BN_add(r0,r0,rsa->p)) goto err;
 511         if (!BN_mul(&r1,r0,rsa->q,ctx)) goto err;
 512         if (!BN_add(r0,&r1,&m1)) goto err;
 513
 514         if (rsa->e && rsa->n)
 515                 {
 516                 if (!rsa->meth->bn_mod_exp(&vrfy,r0,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err;
 517                 /* If 'I' was greater than (or equal to) rsa->n, the operation
 518                  * will be equivalent to using 'I mod n'. However, the result of
 519                  * the verify will *always* be less than 'n' so we don't check
 520                  * for absolute equality, just congruency. */
 521                 if (!BN_sub(&vrfy, &vrfy, I)) goto err;
 522                 if (!BN_mod(&vrfy, &vrfy, rsa->n, ctx)) goto err;
 523                 if (BN_get_sign(&vrfy))
 524                         if (!BN_add(&vrfy, &vrfy, rsa->n)) goto err;
 525                 if (!BN_is_zero(&vrfy))
 526                         /* 'I' and 'vrfy' aren't congruent mod n. Don't leak
 527                          * miscalculated CRT output, just do a raw (slower)
 528                          * mod_exp and return that instead. */
 529                         if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,NULL)) goto err;
 530                 }
 531         ret=1;
 532 err:
 533         BN_clear_free(&m1);
 534         BN_clear_free(&r1);
 535         BN_clear_free(&vrfy);
 536         BN_CTX_free(ctx);
 537         return(ret);
 538         }
 539
 540 static int RSA_eay_init(RSA *rsa)
 541         {
 542         rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
 543         return(1);
 544         }
 545
 546 static int RSA_eay_finish(RSA *rsa)
 547         {
 548         if (rsa->_method_mod_n != NULL)
 549                 BN_MONT_CTX_free(rsa->_method_mod_n);
 550         if (rsa->_method_mod_p != NULL)
 551                 BN_MONT_CTX_free(rsa->_method_mod_p);
 552         if (rsa->_method_mod_q != NULL)
 553                 BN_MONT_CTX_free(rsa->_method_mod_q);
 554         return(1);
 555         }
 556
 557 #endif