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
  65 #ifndef RSA_NULL
  66
  67 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
  68                 unsigned char *to, RSA *rsa,int padding);
  69 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
  70                 unsigned char *to, RSA *rsa,int padding);
  71 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
  72                 unsigned char *to, RSA *rsa,int padding);
  73 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
  74                 unsigned char *to, RSA *rsa,int padding);
  75 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx);
  76 static int RSA_eay_init(RSA *rsa);
  77 static int RSA_eay_finish(RSA *rsa);
  78 static RSA_METHOD rsa_pkcs1_eay_meth={
  79         "Eric Young's PKCS#1 RSA",
  80         RSA_eay_public_encrypt,
  81         RSA_eay_public_decrypt, /* signature verification */
  82         RSA_eay_private_encrypt, /* signing */
  83         RSA_eay_private_decrypt,
  84         RSA_eay_mod_exp,
  85         BN_mod_exp_mont, /* XXX probably we should not use Montgomery if  e == 3 */
  86         RSA_eay_init,
  87         RSA_eay_finish,
  88         0, /* flags */
  89         NULL,
  90         0, /* rsa_sign */
  91         0, /* rsa_verify */
  92         NULL /* rsa_keygen */
  93         };
  94
  95 const RSA_METHOD *RSA_PKCS1_SSLeay(void)
  96         {
  97         return(&rsa_pkcs1_eay_meth);
  98         }
  99
 100 /* Usage example;
 101  *    MONT_HELPER(rsa, bn_ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 102  */
 103 #define MONT_HELPER(rsa, ctx, m, pre_cond, err_instr) \
 104         if((pre_cond) && ((rsa)->_method_mod_##m == NULL) && \
 105                         !BN_MONT_CTX_set_locked(&((rsa)->_method_mod_##m), \
 106                                 CRYPTO_LOCK_RSA, \
 107                                 (rsa)->m, (ctx))) \
 108                 err_instr
 109
 110 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 111              unsigned char *to, RSA *rsa, int padding)
 112         {
 113         BIGNUM *f,*ret;
 114         int i,j,k,num=0,r= -1;
 115         unsigned char *buf=NULL;
 116         BN_CTX *ctx=NULL;
 117
 118         if ((ctx=BN_CTX_new()) == NULL) goto err;
 119         BN_CTX_start(ctx);
 120         f = BN_CTX_get(ctx);
 121         ret = BN_CTX_get(ctx);
 122         num=BN_num_bytes(rsa->n);
 123         buf = OPENSSL_malloc(num);
 124         if (!f || !ret || !buf)
 125                 {
 126                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
 127                 goto err;
 128                 }
 129
 130         switch (padding)
 131                 {
 132         case RSA_PKCS1_PADDING:
 133                 i=RSA_padding_add_PKCS1_type_2(buf,num,from,flen);
 134                 break;
 135 #ifndef OPENSSL_NO_SHA
 136         case RSA_PKCS1_OAEP_PADDING:
 137                 i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
 138                 break;
 139 #endif
 140         case RSA_SSLV23_PADDING:
 141                 i=RSA_padding_add_SSLv23(buf,num,from,flen);
 142                 break;
 143         case RSA_NO_PADDING:
 144                 i=RSA_padding_add_none(buf,num,from,flen);
 145                 break;
 146         default:
 147                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 148                 goto err;
 149                 }
 150         if (i <= 0) goto err;
 151
 152         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 153
 154         if (BN_ucmp(f, rsa->n) >= 0)
 155                 {
 156                 /* usually the padding functions would catch this */
 157                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 158                 goto err;
 159                 }
 160
 161         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 162
 163         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 164                 rsa->_method_mod_n)) goto err;
 165
 166         /* put in leading 0 bytes if the number is less than the
 167          * length of the modulus */
 168         j=BN_num_bytes(ret);
 169         i=BN_bn2bin(ret,&(to[num-j]));
 170         for (k=0; k<(num-i); k++)
 171                 to[k]=0;
 172
 173         r=num;
 174 err:
 175         if (ctx != NULL)
 176                 {
 177                 BN_CTX_end(ctx);
 178                 BN_CTX_free(ctx);
 179                 }
 180         if (buf != NULL)
 181                 {
 182                 OPENSSL_cleanse(buf,num);
 183                 OPENSSL_free(buf);
 184                 }
 185         return(r);
 186         }
 187
 188 static BN_BLINDING *rsa_get_blinding(RSA *rsa, BIGNUM **r, int *local, BN_CTX *ctx)
 189 {
 190         BN_BLINDING *ret;
 191
 192         if (rsa->blinding == NULL)
 193                 {
 194                 if (rsa->blinding == NULL)
 195                         {
 196                         CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 197                         if (rsa->blinding == NULL)
 198                                 rsa->blinding = RSA_setup_blinding(rsa, ctx);
 199                         CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 200                         }
 201                 }
 202
 203         ret = rsa->blinding;
 204         if (ret == NULL)
 205                 return NULL;
 206
 207         if (BN_BLINDING_get_thread_id(ret) != CRYPTO_thread_id())
 208                 {
 209                 *local = 0;
 210                 if (rsa->mt_blinding == NULL)
 211                         {
 212                         CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 213                         if (rsa->mt_blinding == NULL)
 214                                 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
 215                         CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 216                         }
 217                 ret = rsa->mt_blinding;
 218                 }
 219         else
 220                 *local = 1;
 221
 222         return ret;
 223 }
 224
 225 static int rsa_blinding_convert(BN_BLINDING *b, int local, BIGNUM *f,
 226         BIGNUM *r, BN_CTX *ctx)
 227 {
 228         if (local)
 229                 return BN_BLINDING_convert_ex(f, NULL, b, ctx);
 230         else
 231                 {
 232                 int ret;
 233                 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
 234                 ret = BN_BLINDING_convert_ex(f, r, b, ctx);
 235                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
 236                 return ret;
 237                 }
 238 }
 239
 240 static int rsa_blinding_invert(BN_BLINDING *b, int local, BIGNUM *f,
 241         BIGNUM *r, BN_CTX *ctx)
 242 {
 243         if (local)
 244                 return BN_BLINDING_invert_ex(f, NULL, b, ctx);
 245         else
 246                 {
 247                 int ret;
 248                 CRYPTO_r_lock(CRYPTO_LOCK_RSA_BLINDING);
 249                 ret = BN_BLINDING_invert_ex(f, r, b, ctx);
 250                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA_BLINDING);
 251                 return ret;
 252                 }
 253 }
 254
 255 /* signing */
 256 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 257              unsigned char *to, RSA *rsa, int padding)
 258         {
 259         BIGNUM *f, *ret, *br;
 260         int i,j,k,num=0,r= -1;
 261         unsigned char *buf=NULL;
 262         BN_CTX *ctx=NULL;
 263         int local_blinding = 0;
 264         BN_BLINDING *blinding = NULL;
 265
 266         if ((ctx=BN_CTX_new()) == NULL) goto err;
 267         BN_CTX_start(ctx);
 268         f   = BN_CTX_get(ctx);
 269         br  = BN_CTX_get(ctx);
 270         ret = BN_CTX_get(ctx);
 271         num = BN_num_bytes(rsa->n);
 272         buf = OPENSSL_malloc(num);
 273         if(!f || !ret || !buf)
 274                 {
 275                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
 276                 goto err;
 277                 }
 278
 279         switch (padding)
 280                 {
 281         case RSA_PKCS1_PADDING:
 282                 i=RSA_padding_add_PKCS1_type_1(buf,num,from,flen);
 283                 break;
 284         case RSA_NO_PADDING:
 285                 i=RSA_padding_add_none(buf,num,from,flen);
 286                 break;
 287         case RSA_SSLV23_PADDING:
 288         default:
 289                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 290                 goto err;
 291                 }
 292         if (i <= 0) goto err;
 293
 294         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 295
 296         if (BN_ucmp(f, rsa->n) >= 0)
 297                 {
 298                 /* usually the padding functions would catch this */
 299                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 300                 goto err;
 301                 }
 302
 303         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 304                 {
 305                 blinding = rsa_get_blinding(rsa, &br, &local_blinding, ctx);
 306                 if (blinding == NULL)
 307                         {
 308                         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
 309                         goto err;
 310                         }
 311                 }
 312
 313         if (blinding != NULL)
 314                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 315                         goto err;
 316
 317         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 318                 ((rsa->p != NULL) &&
 319                 (rsa->q != NULL) &&
 320                 (rsa->dmp1 != NULL) &&
 321                 (rsa->dmq1 != NULL) &&
 322                 (rsa->iqmp != NULL)) )
 323                 { if (!rsa->meth->rsa_mod_exp(ret,f,rsa,ctx)) goto err; }
 324         else
 325                 {
 326                 MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 327                 if (!rsa->meth->bn_mod_exp(ret,f,rsa->d,rsa->n,ctx,
 328                                 rsa->_method_mod_n)) goto err;
 329                 }
 330
 331         if (blinding)
 332                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 333                         goto err;
 334
 335         /* put in leading 0 bytes if the number is less than the
 336          * length of the modulus */
 337         j=BN_num_bytes(ret);
 338         i=BN_bn2bin(ret,&(to[num-j]));
 339         for (k=0; k<(num-i); k++)
 340                 to[k]=0;
 341
 342         r=num;
 343 err:
 344         if (ctx != NULL)
 345                 {
 346                 BN_CTX_end(ctx);
 347                 BN_CTX_free(ctx);
 348                 }
 349         if (buf != NULL)
 350                 {
 351                 OPENSSL_cleanse(buf,num);
 352                 OPENSSL_free(buf);
 353                 }
 354         return(r);
 355         }
 356
 357 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 358              unsigned char *to, RSA *rsa, int padding)
 359         {
 360         BIGNUM *f, *ret, *br;
 361         int j,num=0,r= -1;
 362         unsigned char *p;
 363         unsigned char *buf=NULL;
 364         BN_CTX *ctx=NULL;
 365         int local_blinding = 0;
 366         BN_BLINDING *blinding = NULL;
 367
 368         if((ctx = BN_CTX_new()) == NULL) goto err;
 369         BN_CTX_start(ctx);
 370         f   = BN_CTX_get(ctx);
 371         br  = BN_CTX_get(ctx);
 372         ret = BN_CTX_get(ctx);
 373         num = BN_num_bytes(rsa->n);
 374         buf = OPENSSL_malloc(num);
 375         if(!f || !ret || !buf)
 376                 {
 377                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
 378                 goto err;
 379                 }
 380
 381         /* This check was for equality but PGP does evil things
 382          * and chops off the top '0' bytes */
 383         if (flen > num)
 384                 {
 385                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 386                 goto err;
 387                 }
 388
 389         /* make data into a big number */
 390         if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;
 391
 392         if (BN_ucmp(f, rsa->n) >= 0)
 393                 {
 394                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 395                 goto err;
 396                 }
 397
 398         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 399                 {
 400                 blinding = rsa_get_blinding(rsa, &br, &local_blinding, ctx);
 401                 if (blinding == NULL)
 402                         {
 403                         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
 404                         goto err;
 405                         }
 406                 }
 407
 408         if (blinding != NULL)
 409                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 410                         goto err;
 411
 412         /* do the decrypt */
 413         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 414                 ((rsa->p != NULL) &&
 415                 (rsa->q != NULL) &&
 416                 (rsa->dmp1 != NULL) &&
 417                 (rsa->dmq1 != NULL) &&
 418                 (rsa->iqmp != NULL)) )
 419                 { if (!rsa->meth->rsa_mod_exp(ret,f,rsa,ctx)) goto err; }
 420         else
 421                 {
 422                 MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 423                 if (!rsa->meth->bn_mod_exp(ret,f,rsa->d,rsa->n,ctx,
 424                                 rsa->_method_mod_n))
 425                         goto err;
 426                 }
 427
 428         if (blinding)
 429                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 430                         goto err;
 431
 432         p=buf;
 433         j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */
 434
 435         switch (padding)
 436                 {
 437         case RSA_PKCS1_PADDING:
 438                 r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
 439                 break;
 440 #ifndef OPENSSL_NO_SHA
 441         case RSA_PKCS1_OAEP_PADDING:
 442                 r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
 443                 break;
 444 #endif
 445         case RSA_SSLV23_PADDING:
 446                 r=RSA_padding_check_SSLv23(to,num,buf,j,num);
 447                 break;
 448         case RSA_NO_PADDING:
 449                 r=RSA_padding_check_none(to,num,buf,j,num);
 450                 break;
 451         default:
 452                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 453                 goto err;
 454                 }
 455         if (r < 0)
 456                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 457
 458 err:
 459         if (ctx != NULL)
 460                 {
 461                 BN_CTX_end(ctx);
 462                 BN_CTX_free(ctx);
 463                 }
 464         if (buf != NULL)
 465                 {
 466                 OPENSSL_cleanse(buf,num);
 467                 OPENSSL_free(buf);
 468                 }
 469         return(r);
 470         }
 471
 472 /* signature verification */
 473 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 474              unsigned char *to, RSA *rsa, int padding)
 475         {
 476         BIGNUM *f,*ret;
 477         int i,num=0,r= -1;
 478         unsigned char *p;
 479         unsigned char *buf=NULL;
 480         BN_CTX *ctx=NULL;
 481
 482         if((ctx = BN_CTX_new()) == NULL) goto err;
 483         BN_CTX_start(ctx);
 484         f = BN_CTX_get(ctx);
 485         ret = BN_CTX_get(ctx);
 486         num=BN_num_bytes(rsa->n);
 487         buf = OPENSSL_malloc(num);
 488         if(!f || !ret || !buf)
 489                 {
 490                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
 491                 goto err;
 492                 }
 493
 494         /* This check was for equality but PGP does evil things
 495          * and chops off the top '0' bytes */
 496         if (flen > num)
 497                 {
 498                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 499                 goto err;
 500                 }
 501
 502         if (BN_bin2bn(from,flen,f) == NULL) goto err;
 503
 504         if (BN_ucmp(f, rsa->n) >= 0)
 505                 {
 506                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 507                 goto err;
 508                 }
 509
 510         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 511
 512         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 513                 rsa->_method_mod_n)) goto err;
 514
 515         p=buf;
 516         i=BN_bn2bin(ret,p);
 517
 518         switch (padding)
 519                 {
 520         case RSA_PKCS1_PADDING:
 521                 r=RSA_padding_check_PKCS1_type_1(to,num,buf,i,num);
 522                 break;
 523         case RSA_NO_PADDING:
 524                 r=RSA_padding_check_none(to,num,buf,i,num);
 525                 break;
 526         default:
 527                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 528                 goto err;
 529                 }
 530         if (r < 0)
 531                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 532
 533 err:
 534         if (ctx != NULL)
 535                 {
 536                 BN_CTX_end(ctx);
 537                 BN_CTX_free(ctx);
 538                 }
 539         if (buf != NULL)
 540                 {
 541                 OPENSSL_cleanse(buf,num);
 542                 OPENSSL_free(buf);
 543                 }
 544         return(r);
 545         }
 546
 547 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 548         {
 549         BIGNUM *r1,*m1,*vrfy;
 550         int ret=0;
 551
 552         BN_CTX_start(ctx);
 553         r1 = BN_CTX_get(ctx);
 554         m1 = BN_CTX_get(ctx);
 555         vrfy = BN_CTX_get(ctx);
 556
 557         MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 558         MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 559         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 560
 561         if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
 562         if (!rsa->meth->bn_mod_exp(m1,r1,rsa->dmq1,rsa->q,ctx,
 563                 rsa->_method_mod_q)) goto err;
 564
 565         if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
 566         if (!rsa->meth->bn_mod_exp(r0,r1,rsa->dmp1,rsa->p,ctx,
 567                 rsa->_method_mod_p)) goto err;
 568
 569         if (!BN_sub(r0,r0,m1)) goto err;
 570         /* This will help stop the size of r0 increasing, which does
 571          * affect the multiply if it optimised for a power of 2 size */
 572         if (BN_is_negative(r0))
 573                 if (!BN_add(r0,r0,rsa->p)) goto err;
 574
 575         if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
 576         if (!BN_mod(r0,r1,rsa->p,ctx)) goto err;
 577         /* If p < q it is occasionally possible for the correction of
 578          * adding 'p' if r0 is negative above to leave the result still
 579          * negative. This can break the private key operations: the following
 580          * second correction should *always* correct this rare occurrence.
 581          * This will *never* happen with OpenSSL generated keys because
 582          * they ensure p > q [steve]
 583          */
 584         if (BN_is_negative(r0))
 585                 if (!BN_add(r0,r0,rsa->p)) goto err;
 586         if (!BN_mul(r1,r0,rsa->q,ctx)) goto err;
 587         if (!BN_add(r0,r1,m1)) goto err;
 588
 589         if (rsa->e && rsa->n)
 590                 {
 591                 if (!rsa->meth->bn_mod_exp(vrfy,r0,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err;
 592                 /* If 'I' was greater than (or equal to) rsa->n, the operation
 593                  * will be equivalent to using 'I mod n'. However, the result of
 594                  * the verify will *always* be less than 'n' so we don't check
 595                  * for absolute equality, just congruency. */
 596                 if (!BN_sub(vrfy, vrfy, I)) goto err;
 597                 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) goto err;
 598                 if (BN_is_negative(vrfy))
 599                         if (!BN_add(vrfy, vrfy, rsa->n)) goto err;
 600                 if (!BN_is_zero(vrfy))
 601                         /* 'I' and 'vrfy' aren't congruent mod n. Don't leak
 602                          * miscalculated CRT output, just do a raw (slower)
 603                          * mod_exp and return that instead. */
 604                         if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,
 605                                         rsa->_method_mod_n)) goto err;
 606                 }
 607         ret=1;
 608 err:
 609         BN_CTX_end(ctx);
 610         return(ret);
 611         }
 612
 613 static int RSA_eay_init(RSA *rsa)
 614         {
 615         rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
 616         return(1);
 617         }
 618
 619 static int RSA_eay_finish(RSA *rsa)
 620         {
 621         if (rsa->_method_mod_n != NULL)
 622                 BN_MONT_CTX_free(rsa->_method_mod_n);
 623         if (rsa->_method_mod_p != NULL)
 624                 BN_MONT_CTX_free(rsa->_method_mod_p);
 625         if (rsa->_method_mod_q != NULL)
 626                 BN_MONT_CTX_free(rsa->_method_mod_q);
 627         return(1);
 628         }
 629
 630 #endif