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  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
  60  *
  61  * Redistribution and use in source and binary forms, with or without
  62  * modification, are permitted provided that the following conditions
  63  * are met:
  64  *
  65  * 1. Redistributions of source code must retain the above copyright
  66  *    notice, this list of conditions and the following disclaimer.
  67  *
  68  * 2. Redistributions in binary form must reproduce the above copyright
  69  *    notice, this list of conditions and the following disclaimer in
  70  *    the documentation and/or other materials provided with the
  71  *    distribution.
  72  *
  73  * 3. All advertising materials mentioning features or use of this
  74  *    software must display the following acknowledgment:
  75  *    "This product includes software developed by the OpenSSL Project
  76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  77  *
  78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  79  *    endorse or promote products derived from this software without
  80  *    prior written permission. For written permission, please contact
  81  *    openssl-core@openssl.org.
  82  *
  83  * 5. Products derived from this software may not be called "OpenSSL"
  84  *    nor may "OpenSSL" appear in their names without prior written
  85  *    permission of the OpenSSL Project.
  86  *
  87  * 6. Redistributions of any form whatsoever must retain the following
  88  *    acknowledgment:
  89  *    "This product includes software developed by the OpenSSL Project
  90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  91  *
  92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 103  * OF THE POSSIBILITY OF SUCH DAMAGE.
 104  * ====================================================================
 105  *
 106  * This product includes cryptographic software written by Eric Young
 107  * (eay@cryptsoft.com).  This product includes software written by Tim
 108  * Hudson (tjh@cryptsoft.com).
 109  *
 110  */
 111
 112 #include <stdio.h>
 113 #include "cryptlib.h"
 114 #include <openssl/bn.h>
 115 #include <openssl/rsa.h>
 116 #include <openssl/rand.h>
 117
 118 #ifndef RSA_NULL
 119
 120 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 121                 unsigned char *to, RSA *rsa,int padding);
 122 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 123                 unsigned char *to, RSA *rsa,int padding);
 124 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 125                 unsigned char *to, RSA *rsa,int padding);
 126 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 127                 unsigned char *to, RSA *rsa,int padding);
 128 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx);
 129 static int RSA_eay_init(RSA *rsa);
 130 static int RSA_eay_finish(RSA *rsa);
 131 static RSA_METHOD rsa_pkcs1_eay_meth={
 132         "Eric Young's PKCS#1 RSA",
 133         RSA_eay_public_encrypt,
 134         RSA_eay_public_decrypt, /* signature verification */
 135         RSA_eay_private_encrypt, /* signing */
 136         RSA_eay_private_decrypt,
 137         RSA_eay_mod_exp,
 138         BN_mod_exp_mont, /* XXX probably we should not use Montgomery if  e == 3 */
 139         RSA_eay_init,
 140         RSA_eay_finish,
 141         0, /* flags */
 142         NULL,
 143         0, /* rsa_sign */
 144         0, /* rsa_verify */
 145         NULL /* rsa_keygen */
 146         };
 147
 148 const RSA_METHOD *RSA_PKCS1_SSLeay(void)
 149         {
 150         return(&rsa_pkcs1_eay_meth);
 151         }
 152
 153 /* Usage example;
 154  *    MONT_HELPER(rsa, bn_ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 155  */
 156 #define MONT_HELPER(rsa, ctx, m, pre_cond, err_instr) \
 157         if((pre_cond) && ((rsa)->_method_mod_##m == NULL) && \
 158                         !BN_MONT_CTX_set_locked(&((rsa)->_method_mod_##m), \
 159                                 CRYPTO_LOCK_RSA, \
 160                                 (rsa)->m, (ctx))) \
 161                 err_instr
 162
 163 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 164              unsigned char *to, RSA *rsa, int padding)
 165         {
 166         BIGNUM *f,*ret;
 167         int i,j,k,num=0,r= -1;
 168         unsigned char *buf=NULL;
 169         BN_CTX *ctx=NULL;
 170
 171         if ((ctx=BN_CTX_new()) == NULL) goto err;
 172         BN_CTX_start(ctx);
 173         f = BN_CTX_get(ctx);
 174         ret = BN_CTX_get(ctx);
 175         num=BN_num_bytes(rsa->n);
 176         buf = OPENSSL_malloc(num);
 177         if (!f || !ret || !buf)
 178                 {
 179                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
 180                 goto err;
 181                 }
 182
 183         switch (padding)
 184                 {
 185         case RSA_PKCS1_PADDING:
 186                 i=RSA_padding_add_PKCS1_type_2(buf,num,from,flen);
 187                 break;
 188 #ifndef OPENSSL_NO_SHA
 189         case RSA_PKCS1_OAEP_PADDING:
 190                 i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
 191                 break;
 192 #endif
 193         case RSA_SSLV23_PADDING:
 194                 i=RSA_padding_add_SSLv23(buf,num,from,flen);
 195                 break;
 196         case RSA_NO_PADDING:
 197                 i=RSA_padding_add_none(buf,num,from,flen);
 198                 break;
 199         default:
 200                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 201                 goto err;
 202                 }
 203         if (i <= 0) goto err;
 204
 205         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 206
 207         if (BN_ucmp(f, rsa->n) >= 0)
 208                 {
 209                 /* usually the padding functions would catch this */
 210                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 211                 goto err;
 212                 }
 213
 214         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 215
 216         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 217                 rsa->_method_mod_n)) goto err;
 218
 219         /* put in leading 0 bytes if the number is less than the
 220          * length of the modulus */
 221         j=BN_num_bytes(ret);
 222         i=BN_bn2bin(ret,&(to[num-j]));
 223         for (k=0; k<(num-i); k++)
 224                 to[k]=0;
 225
 226         r=num;
 227 err:
 228         if (ctx != NULL)
 229                 {
 230                 BN_CTX_end(ctx);
 231                 BN_CTX_free(ctx);
 232                 }
 233         if (buf != NULL)
 234                 {
 235                 OPENSSL_cleanse(buf,num);
 236                 OPENSSL_free(buf);
 237                 }
 238         return(r);
 239         }
 240
 241 static BN_BLINDING *rsa_get_blinding(RSA *rsa, BIGNUM **r, int *local, BN_CTX *ctx)
 242 {
 243         BN_BLINDING *ret;
 244
 245         if (rsa->blinding == NULL)
 246                 {
 247                 if (rsa->blinding == NULL)
 248                         {
 249                         CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 250                         if (rsa->blinding == NULL)
 251                                 rsa->blinding = RSA_setup_blinding(rsa, ctx);
 252                         CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 253                         }
 254                 }
 255
 256         ret = rsa->blinding;
 257         if (ret == NULL)
 258                 return NULL;
 259
 260         if (BN_BLINDING_get_thread_id(ret) != CRYPTO_thread_id())
 261                 {
 262                 *local = 0;
 263                 if (rsa->mt_blinding == NULL)
 264                         {
 265                         CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 266                         if (rsa->mt_blinding == NULL)
 267                                 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
 268                         CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 269                         }
 270                 ret = rsa->mt_blinding;
 271                 }
 272         else
 273                 *local = 1;
 274
 275         return ret;
 276 }
 277
 278 static int rsa_blinding_convert(BN_BLINDING *b, int local, BIGNUM *f,
 279         BIGNUM *r, BN_CTX *ctx)
 280 {
 281         if (local)
 282                 return BN_BLINDING_convert_ex(f, NULL, b, ctx);
 283         else
 284                 {
 285                 int ret;
 286                 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
 287                 ret = BN_BLINDING_convert_ex(f, r, b, ctx);
 288                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
 289                 return ret;
 290                 }
 291 }
 292
 293 static int rsa_blinding_invert(BN_BLINDING *b, int local, BIGNUM *f,
 294         BIGNUM *r, BN_CTX *ctx)
 295 {
 296         if (local)
 297                 return BN_BLINDING_invert_ex(f, NULL, b, ctx);
 298         else
 299                 {
 300                 int ret;
 301                 CRYPTO_r_lock(CRYPTO_LOCK_RSA_BLINDING);
 302                 ret = BN_BLINDING_invert_ex(f, r, b, ctx);
 303                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA_BLINDING);
 304                 return ret;
 305                 }
 306 }
 307
 308 /* signing */
 309 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 310              unsigned char *to, RSA *rsa, int padding)
 311         {
 312         BIGNUM *f, *ret, *br, *res;
 313         int i,j,k,num=0,r= -1;
 314         unsigned char *buf=NULL;
 315         BN_CTX *ctx=NULL;
 316         int local_blinding = 0;
 317         BN_BLINDING *blinding = NULL;
 318
 319         if ((ctx=BN_CTX_new()) == NULL) goto err;
 320         BN_CTX_start(ctx);
 321         f   = BN_CTX_get(ctx);
 322         br  = BN_CTX_get(ctx);
 323         ret = BN_CTX_get(ctx);
 324         num = BN_num_bytes(rsa->n);
 325         buf = OPENSSL_malloc(num);
 326         if(!f || !ret || !buf)
 327                 {
 328                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
 329                 goto err;
 330                 }
 331
 332         switch (padding)
 333                 {
 334         case RSA_PKCS1_PADDING:
 335                 i=RSA_padding_add_PKCS1_type_1(buf,num,from,flen);
 336                 break;
 337         case RSA_X931_PADDING:
 338                 i=RSA_padding_add_X931(buf,num,from,flen);
 339                 break;
 340         case RSA_NO_PADDING:
 341                 i=RSA_padding_add_none(buf,num,from,flen);
 342                 break;
 343         case RSA_SSLV23_PADDING:
 344         default:
 345                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 346                 goto err;
 347                 }
 348         if (i <= 0) goto err;
 349
 350         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 351
 352         if (BN_ucmp(f, rsa->n) >= 0)
 353                 {
 354                 /* usually the padding functions would catch this */
 355                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 356                 goto err;
 357                 }
 358
 359         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 360                 {
 361                 blinding = rsa_get_blinding(rsa, &br, &local_blinding, ctx);
 362                 if (blinding == NULL)
 363                         {
 364                         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
 365                         goto err;
 366                         }
 367                 }
 368
 369         if (blinding != NULL)
 370                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 371                         goto err;
 372
 373         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 374                 ((rsa->p != NULL) &&
 375                 (rsa->q != NULL) &&
 376                 (rsa->dmp1 != NULL) &&
 377                 (rsa->dmq1 != NULL) &&
 378                 (rsa->iqmp != NULL)) )
 379                 {
 380                 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
 381                 }
 382         else
 383                 {
 384                 BIGNUM local_d;
 385                 BIGNUM *d = NULL;
 386
 387                 if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
 388                         {
 389                         BN_init(&local_d);
 390                         d = &local_d;
 391                         BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
 392                         }
 393                 else
 394                         d = rsa->d;
 395
 396                 MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 397
 398                 if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 399                                 rsa->_method_mod_n)) goto err;
 400                 }
 401
 402         if (blinding)
 403                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 404                         goto err;
 405
 406         if (padding == RSA_X931_PADDING)
 407                 {
 408                 BN_sub(f, rsa->n, ret);
 409                 if (BN_cmp(ret, f))
 410                         res = f;
 411                 else
 412                         res = ret;
 413                 }
 414         else
 415                 res = ret;
 416
 417         /* put in leading 0 bytes if the number is less than the
 418          * length of the modulus */
 419         j=BN_num_bytes(res);
 420         i=BN_bn2bin(res,&(to[num-j]));
 421         for (k=0; k<(num-i); k++)
 422                 to[k]=0;
 423
 424         r=num;
 425 err:
 426         if (ctx != NULL)
 427                 {
 428                 BN_CTX_end(ctx);
 429                 BN_CTX_free(ctx);
 430                 }
 431         if (buf != NULL)
 432                 {
 433                 OPENSSL_cleanse(buf,num);
 434                 OPENSSL_free(buf);
 435                 }
 436         return(r);
 437         }
 438
 439 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 440              unsigned char *to, RSA *rsa, int padding)
 441         {
 442         BIGNUM *f, *ret, *br;
 443         int j,num=0,r= -1;
 444         unsigned char *p;
 445         unsigned char *buf=NULL;
 446         BN_CTX *ctx=NULL;
 447         int local_blinding = 0;
 448         BN_BLINDING *blinding = NULL;
 449
 450         if((ctx = BN_CTX_new()) == NULL) goto err;
 451         BN_CTX_start(ctx);
 452         f   = BN_CTX_get(ctx);
 453         br  = BN_CTX_get(ctx);
 454         ret = BN_CTX_get(ctx);
 455         num = BN_num_bytes(rsa->n);
 456         buf = OPENSSL_malloc(num);
 457         if(!f || !ret || !buf)
 458                 {
 459                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
 460                 goto err;
 461                 }
 462
 463         /* This check was for equality but PGP does evil things
 464          * and chops off the top '0' bytes */
 465         if (flen > num)
 466                 {
 467                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 468                 goto err;
 469                 }
 470
 471         /* make data into a big number */
 472         if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;
 473
 474         if (BN_ucmp(f, rsa->n) >= 0)
 475                 {
 476                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 477                 goto err;
 478                 }
 479
 480         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 481                 {
 482                 blinding = rsa_get_blinding(rsa, &br, &local_blinding, ctx);
 483                 if (blinding == NULL)
 484                         {
 485                         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
 486                         goto err;
 487                         }
 488                 }
 489
 490         if (blinding != NULL)
 491                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 492                         goto err;
 493
 494         /* do the decrypt */
 495         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 496                 ((rsa->p != NULL) &&
 497                 (rsa->q != NULL) &&
 498                 (rsa->dmp1 != NULL) &&
 499                 (rsa->dmq1 != NULL) &&
 500                 (rsa->iqmp != NULL)) )
 501                 {
 502                 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
 503                 }
 504         else
 505                 {
 506                 BIGNUM local_d;
 507                 BIGNUM *d = NULL;
 508
 509                 if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
 510                         {
 511                         d = &local_d;
 512                         BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
 513                         }
 514                 else
 515                         d = rsa->d;
 516
 517                 MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 518                 if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 519                                 rsa->_method_mod_n))
 520                   goto err;
 521                 }
 522
 523         if (blinding)
 524                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 525                         goto err;
 526
 527         p=buf;
 528         j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */
 529
 530         switch (padding)
 531                 {
 532         case RSA_PKCS1_PADDING:
 533                 r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
 534                 break;
 535 #ifndef OPENSSL_NO_SHA
 536         case RSA_PKCS1_OAEP_PADDING:
 537                 r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
 538                 break;
 539 #endif
 540         case RSA_SSLV23_PADDING:
 541                 r=RSA_padding_check_SSLv23(to,num,buf,j,num);
 542                 break;
 543         case RSA_NO_PADDING:
 544                 r=RSA_padding_check_none(to,num,buf,j,num);
 545                 break;
 546         default:
 547                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 548                 goto err;
 549                 }
 550         if (r < 0)
 551                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 552
 553 err:
 554         if (ctx != NULL)
 555                 {
 556                 BN_CTX_end(ctx);
 557                 BN_CTX_free(ctx);
 558                 }
 559         if (buf != NULL)
 560                 {
 561                 OPENSSL_cleanse(buf,num);
 562                 OPENSSL_free(buf);
 563                 }
 564         return(r);
 565         }
 566
 567 /* signature verification */
 568 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 569              unsigned char *to, RSA *rsa, int padding)
 570         {
 571         BIGNUM *f,*ret;
 572         int i,num=0,r= -1;
 573         unsigned char *p;
 574         unsigned char *buf=NULL;
 575         BN_CTX *ctx=NULL;
 576
 577         if((ctx = BN_CTX_new()) == NULL) goto err;
 578         BN_CTX_start(ctx);
 579         f = BN_CTX_get(ctx);
 580         ret = BN_CTX_get(ctx);
 581         num=BN_num_bytes(rsa->n);
 582         buf = OPENSSL_malloc(num);
 583         if(!f || !ret || !buf)
 584                 {
 585                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
 586                 goto err;
 587                 }
 588
 589         /* This check was for equality but PGP does evil things
 590          * and chops off the top '0' bytes */
 591         if (flen > num)
 592                 {
 593                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 594                 goto err;
 595                 }
 596
 597         if (BN_bin2bn(from,flen,f) == NULL) goto err;
 598
 599         if (BN_ucmp(f, rsa->n) >= 0)
 600                 {
 601                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 602                 goto err;
 603                 }
 604
 605         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 606
 607         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 608                 rsa->_method_mod_n)) goto err;
 609
 610         if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12))
 611                 BN_sub(ret, rsa->n, ret);
 612
 613         p=buf;
 614         i=BN_bn2bin(ret,p);
 615
 616         switch (padding)
 617                 {
 618         case RSA_PKCS1_PADDING:
 619                 r=RSA_padding_check_PKCS1_type_1(to,num,buf,i,num);
 620                 break;
 621         case RSA_X931_PADDING:
 622                 r=RSA_padding_check_X931(to,num,buf,i,num);
 623                 break;
 624         case RSA_NO_PADDING:
 625                 r=RSA_padding_check_none(to,num,buf,i,num);
 626                 break;
 627         default:
 628                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 629                 goto err;
 630                 }
 631         if (r < 0)
 632                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 633
 634 err:
 635         if (ctx != NULL)
 636                 {
 637                 BN_CTX_end(ctx);
 638                 BN_CTX_free(ctx);
 639                 }
 640         if (buf != NULL)
 641                 {
 642                 OPENSSL_cleanse(buf,num);
 643                 OPENSSL_free(buf);
 644                 }
 645         return(r);
 646         }
 647
 648 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 649         {
 650         BIGNUM *r1,*m1,*vrfy;
 651         BIGNUM local_dmp1, local_dmq1;
 652         BIGNUM *dmp1, *dmq1;
 653         int ret=0;
 654
 655         BN_CTX_start(ctx);
 656         r1 = BN_CTX_get(ctx);
 657         m1 = BN_CTX_get(ctx);
 658         vrfy = BN_CTX_get(ctx);
 659
 660         MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 661         MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 662         MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 663
 664         if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
 665         if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
 666                 {
 667                 dmq1 = &local_dmq1;
 668                 BN_with_flags(dmq1, rsa->dmq1, BN_FLG_EXP_CONSTTIME);
 669                 }
 670         else
 671                 dmq1 = rsa->dmq1;
 672         if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
 673                 rsa->_method_mod_q)) goto err;
 674
 675         if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
 676         if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
 677                 {
 678                 dmp1 = &local_dmp1;
 679                 BN_with_flags(dmp1, rsa->dmp1, BN_FLG_EXP_CONSTTIME);
 680                 }
 681         else
 682                 dmp1 = rsa->dmp1;
 683         if (!rsa->meth->bn_mod_exp(r0,r1,dmp1,rsa->p,ctx,
 684                 rsa->_method_mod_p)) goto err;
 685
 686         if (!BN_sub(r0,r0,m1)) goto err;
 687         /* This will help stop the size of r0 increasing, which does
 688          * affect the multiply if it optimised for a power of 2 size */
 689         if (BN_is_negative(r0))
 690                 if (!BN_add(r0,r0,rsa->p)) goto err;
 691
 692         if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
 693         if (!BN_mod(r0,r1,rsa->p,ctx)) goto err;
 694         /* If p < q it is occasionally possible for the correction of
 695          * adding 'p' if r0 is negative above to leave the result still
 696          * negative. This can break the private key operations: the following
 697          * second correction should *always* correct this rare occurrence.
 698          * This will *never* happen with OpenSSL generated keys because
 699          * they ensure p > q [steve]
 700          */
 701         if (BN_is_negative(r0))
 702                 if (!BN_add(r0,r0,rsa->p)) goto err;
 703         if (!BN_mul(r1,r0,rsa->q,ctx)) goto err;
 704         if (!BN_add(r0,r1,m1)) goto err;
 705
 706         if (rsa->e && rsa->n)
 707                 {
 708                 if (!rsa->meth->bn_mod_exp(vrfy,r0,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err;
 709                 /* If 'I' was greater than (or equal to) rsa->n, the operation
 710                  * will be equivalent to using 'I mod n'. However, the result of
 711                  * the verify will *always* be less than 'n' so we don't check
 712                  * for absolute equality, just congruency. */
 713                 if (!BN_sub(vrfy, vrfy, I)) goto err;
 714                 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) goto err;
 715                 if (BN_is_negative(vrfy))
 716                         if (!BN_add(vrfy, vrfy, rsa->n)) goto err;
 717                 if (!BN_is_zero(vrfy))
 718                         {
 719                         /* 'I' and 'vrfy' aren't congruent mod n. Don't leak
 720                          * miscalculated CRT output, just do a raw (slower)
 721                          * mod_exp and return that instead. */
 722
 723                         BIGNUM local_d;
 724                         BIGNUM *d = NULL;
 725
 726                         if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
 727                                 {
 728                                 d = &local_d;
 729                                 BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
 730                                 }
 731                         else
 732                                 d = rsa->d;
 733                         if (!rsa->meth->bn_mod_exp(r0,I,d,rsa->n,ctx,
 734                                                    rsa->_method_mod_n)) goto err;
 735                         }
 736                 }
 737         ret=1;
 738 err:
 739         BN_CTX_end(ctx);
 740         return(ret);
 741         }
 742
 743 static int RSA_eay_init(RSA *rsa)
 744         {
 745         rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
 746         return(1);
 747         }
 748
 749 static int RSA_eay_finish(RSA *rsa)
 750         {
 751         if (rsa->_method_mod_n != NULL)
 752                 BN_MONT_CTX_free(rsa->_method_mod_n);
 753         if (rsa->_method_mod_p != NULL)
 754                 BN_MONT_CTX_free(rsa->_method_mod_p);
 755         if (rsa->_method_mod_q != NULL)
 756                 BN_MONT_CTX_free(rsa->_method_mod_q);
 757         return(1);
 758         }
 759
 760 #endif