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) 1998-2006 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 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 154              unsigned char *to, RSA *rsa, int padding)
 155         {
 156         BIGNUM *f,*ret;
 157         int i,j,k,num=0,r= -1;
 158         unsigned char *buf=NULL;
 159         BN_CTX *ctx=NULL;
 160
 161         if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
 162                 {
 163                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
 164                 return -1;
 165                 }
 166
 167         if (BN_ucmp(rsa->n, rsa->e) <= 0)
 168                 {
 169                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 170                 return -1;
 171                 }
 172
 173         /* for large moduli, enforce exponent limit */
 174         if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
 175                 {
 176                 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
 177                         {
 178                         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 179                         return -1;
 180                         }
 181                 }
 182
 183         if ((ctx=BN_CTX_new()) == NULL) goto err;
 184         BN_CTX_start(ctx);
 185         f = BN_CTX_get(ctx);
 186         ret = BN_CTX_get(ctx);
 187         num=BN_num_bytes(rsa->n);
 188         buf = OPENSSL_malloc(num);
 189         if (!f || !ret || !buf)
 190                 {
 191                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
 192                 goto err;
 193                 }
 194
 195         switch (padding)
 196                 {
 197         case RSA_PKCS1_PADDING:
 198                 i=RSA_padding_add_PKCS1_type_2(buf,num,from,flen);
 199                 break;
 200 #ifndef OPENSSL_NO_SHA
 201         case RSA_PKCS1_OAEP_PADDING:
 202                 i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
 203                 break;
 204 #endif
 205         case RSA_SSLV23_PADDING:
 206                 i=RSA_padding_add_SSLv23(buf,num,from,flen);
 207                 break;
 208         case RSA_NO_PADDING:
 209                 i=RSA_padding_add_none(buf,num,from,flen);
 210                 break;
 211         default:
 212                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 213                 goto err;
 214                 }
 215         if (i <= 0) goto err;
 216
 217         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 218
 219         if (BN_ucmp(f, rsa->n) >= 0)
 220                 {
 221                 /* usually the padding functions would catch this */
 222                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 223                 goto err;
 224                 }
 225
 226         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 227                 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 228                         goto err;
 229
 230         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 231                 rsa->_method_mod_n)) goto err;
 232
 233         /* put in leading 0 bytes if the number is less than the
 234          * length of the modulus */
 235         j=BN_num_bytes(ret);
 236         i=BN_bn2bin(ret,&(to[num-j]));
 237         for (k=0; k<(num-i); k++)
 238                 to[k]=0;
 239
 240         r=num;
 241 err:
 242         if (ctx != NULL)
 243                 {
 244                 BN_CTX_end(ctx);
 245                 BN_CTX_free(ctx);
 246                 }
 247         if (buf != NULL)
 248                 {
 249                 OPENSSL_cleanse(buf,num);
 250                 OPENSSL_free(buf);
 251                 }
 252         return(r);
 253         }
 254
 255 static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
 256 {
 257         BN_BLINDING *ret;
 258         int got_write_lock = 0;
 259         CRYPTO_THREADID cur;
 260
 261         CRYPTO_r_lock(CRYPTO_LOCK_RSA);
 262
 263         if (rsa->blinding == NULL)
 264                 {
 265                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 266                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 267                 got_write_lock = 1;
 268
 269                 if (rsa->blinding == NULL)
 270                         rsa->blinding = RSA_setup_blinding(rsa, ctx);
 271                 }
 272
 273         ret = rsa->blinding;
 274         if (ret == NULL)
 275                 goto err;
 276
 277         CRYPTO_THREADID_current(&cur);
 278         if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret)))
 279                 {
 280                 /* rsa->blinding is ours! */
 281
 282                 *local = 1;
 283                 }
 284         else
 285                 {
 286                 /* resort to rsa->mt_blinding instead */
 287
 288                 *local = 0; /* instructs rsa_blinding_convert(), rsa_blinding_invert()
 289                              * that the BN_BLINDING is shared, meaning that accesses
 290                              * require locks, and that the blinding factor must be
 291                              * stored outside the BN_BLINDING
 292                              */
 293
 294                 if (rsa->mt_blinding == NULL)
 295                         {
 296                         if (!got_write_lock)
 297                                 {
 298                                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 299                                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 300                                 got_write_lock = 1;
 301                                 }
 302
 303                         if (rsa->mt_blinding == NULL)
 304                                 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
 305                         }
 306                 ret = rsa->mt_blinding;
 307                 }
 308
 309  err:
 310         if (got_write_lock)
 311                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 312         else
 313                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 314         return ret;
 315 }
 316
 317 static int rsa_blinding_convert(BN_BLINDING *b, int local, BIGNUM *f,
 318         BIGNUM *r, BN_CTX *ctx)
 319 {
 320         if (local)
 321                 return BN_BLINDING_convert_ex(f, NULL, b, ctx);
 322         else
 323                 {
 324                 int ret;
 325                 CRYPTO_r_lock(CRYPTO_LOCK_RSA_BLINDING);
 326                 ret = BN_BLINDING_convert_ex(f, r, b, ctx);
 327                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA_BLINDING);
 328                 return ret;
 329                 }
 330 }
 331
 332 static int rsa_blinding_invert(BN_BLINDING *b, int local, BIGNUM *f,
 333         BIGNUM *r, BN_CTX *ctx)
 334 {
 335         if (local)
 336                 return BN_BLINDING_invert_ex(f, NULL, b, ctx);
 337         else
 338                 {
 339                 int ret;
 340                 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
 341                 ret = BN_BLINDING_invert_ex(f, r, b, ctx);
 342                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
 343                 return ret;
 344                 }
 345 }
 346
 347 /* signing */
 348 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 349              unsigned char *to, RSA *rsa, int padding)
 350         {
 351         BIGNUM *f, *ret, *br, *res;
 352         int i,j,k,num=0,r= -1;
 353         unsigned char *buf=NULL;
 354         BN_CTX *ctx=NULL;
 355         int local_blinding = 0;
 356         BN_BLINDING *blinding = NULL;
 357
 358         if ((ctx=BN_CTX_new()) == NULL) goto err;
 359         BN_CTX_start(ctx);
 360         f   = BN_CTX_get(ctx);
 361         br  = BN_CTX_get(ctx);
 362         ret = BN_CTX_get(ctx);
 363         num = BN_num_bytes(rsa->n);
 364         buf = OPENSSL_malloc(num);
 365         if(!f || !ret || !buf)
 366                 {
 367                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
 368                 goto err;
 369                 }
 370
 371         switch (padding)
 372                 {
 373         case RSA_PKCS1_PADDING:
 374                 i=RSA_padding_add_PKCS1_type_1(buf,num,from,flen);
 375                 break;
 376         case RSA_X931_PADDING:
 377                 i=RSA_padding_add_X931(buf,num,from,flen);
 378                 break;
 379         case RSA_NO_PADDING:
 380                 i=RSA_padding_add_none(buf,num,from,flen);
 381                 break;
 382         case RSA_SSLV23_PADDING:
 383         default:
 384                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 385                 goto err;
 386                 }
 387         if (i <= 0) goto err;
 388
 389         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 390
 391         if (BN_ucmp(f, rsa->n) >= 0)
 392                 {
 393                 /* usually the padding functions would catch this */
 394                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,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, &local_blinding, ctx);
 401                 if (blinding == NULL)
 402                         {
 403                         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 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         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 413                 ((rsa->p != NULL) &&
 414                 (rsa->q != NULL) &&
 415                 (rsa->dmp1 != NULL) &&
 416                 (rsa->dmq1 != NULL) &&
 417                 (rsa->iqmp != NULL)) )
 418                 {
 419                 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
 420                 }
 421         else
 422                 {
 423                 BIGNUM local_d;
 424                 BIGNUM *d = NULL;
 425
 426                 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 427                         {
 428                         BN_init(&local_d);
 429                         d = &local_d;
 430                         BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 431                         }
 432                 else
 433                         d= rsa->d;
 434
 435                 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 436                         if(!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 437                                 goto err;
 438
 439                 if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 440                                 rsa->_method_mod_n)) goto err;
 441                 }
 442
 443         if (blinding)
 444                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 445                         goto err;
 446
 447         if (padding == RSA_X931_PADDING)
 448                 {
 449                 BN_sub(f, rsa->n, ret);
 450                 if (BN_cmp(ret, f))
 451                         res = f;
 452                 else
 453                         res = ret;
 454                 }
 455         else
 456                 res = ret;
 457
 458         /* put in leading 0 bytes if the number is less than the
 459          * length of the modulus */
 460         j=BN_num_bytes(res);
 461         i=BN_bn2bin(res,&(to[num-j]));
 462         for (k=0; k<(num-i); k++)
 463                 to[k]=0;
 464
 465         r=num;
 466 err:
 467         if (ctx != NULL)
 468                 {
 469                 BN_CTX_end(ctx);
 470                 BN_CTX_free(ctx);
 471                 }
 472         if (buf != NULL)
 473                 {
 474                 OPENSSL_cleanse(buf,num);
 475                 OPENSSL_free(buf);
 476                 }
 477         return(r);
 478         }
 479
 480 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 481              unsigned char *to, RSA *rsa, int padding)
 482         {
 483         BIGNUM *f, *ret, *br;
 484         int j,num=0,r= -1;
 485         unsigned char *p;
 486         unsigned char *buf=NULL;
 487         BN_CTX *ctx=NULL;
 488         int local_blinding = 0;
 489         BN_BLINDING *blinding = NULL;
 490
 491         if((ctx = BN_CTX_new()) == NULL) goto err;
 492         BN_CTX_start(ctx);
 493         f   = BN_CTX_get(ctx);
 494         br  = BN_CTX_get(ctx);
 495         ret = BN_CTX_get(ctx);
 496         num = BN_num_bytes(rsa->n);
 497         buf = OPENSSL_malloc(num);
 498         if(!f || !ret || !buf)
 499                 {
 500                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
 501                 goto err;
 502                 }
 503
 504         /* This check was for equality but PGP does evil things
 505          * and chops off the top '0' bytes */
 506         if (flen > num)
 507                 {
 508                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 509                 goto err;
 510                 }
 511
 512         /* make data into a big number */
 513         if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;
 514
 515         if (BN_ucmp(f, rsa->n) >= 0)
 516                 {
 517                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 518                 goto err;
 519                 }
 520
 521         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 522                 {
 523                 blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 524                 if (blinding == NULL)
 525                         {
 526                         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
 527                         goto err;
 528                         }
 529                 }
 530
 531         if (blinding != NULL)
 532                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 533                         goto err;
 534
 535         /* do the decrypt */
 536         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 537                 ((rsa->p != NULL) &&
 538                 (rsa->q != NULL) &&
 539                 (rsa->dmp1 != NULL) &&
 540                 (rsa->dmq1 != NULL) &&
 541                 (rsa->iqmp != NULL)) )
 542                 {
 543                 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
 544                 }
 545         else
 546                 {
 547                 BIGNUM local_d;
 548                 BIGNUM *d = NULL;
 549
 550                 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 551                         {
 552                         d = &local_d;
 553                         BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 554                         }
 555                 else
 556                         d = rsa->d;
 557
 558                 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 559                         if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 560                                 goto err;
 561                 if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 562                                 rsa->_method_mod_n))
 563                   goto err;
 564                 }
 565
 566         if (blinding)
 567                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 568                         goto err;
 569
 570         p=buf;
 571         j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */
 572
 573         switch (padding)
 574                 {
 575         case RSA_PKCS1_PADDING:
 576                 r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
 577                 break;
 578 #ifndef OPENSSL_NO_SHA
 579         case RSA_PKCS1_OAEP_PADDING:
 580                 r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
 581                 break;
 582 #endif
 583         case RSA_SSLV23_PADDING:
 584                 r=RSA_padding_check_SSLv23(to,num,buf,j,num);
 585                 break;
 586         case RSA_NO_PADDING:
 587                 r=RSA_padding_check_none(to,num,buf,j,num);
 588                 break;
 589         default:
 590                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 591                 goto err;
 592                 }
 593         if (r < 0)
 594                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 595
 596 err:
 597         if (ctx != NULL)
 598                 {
 599                 BN_CTX_end(ctx);
 600                 BN_CTX_free(ctx);
 601                 }
 602         if (buf != NULL)
 603                 {
 604                 OPENSSL_cleanse(buf,num);
 605                 OPENSSL_free(buf);
 606                 }
 607         return(r);
 608         }
 609
 610 /* signature verification */
 611 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 612              unsigned char *to, RSA *rsa, int padding)
 613         {
 614         BIGNUM *f,*ret;
 615         int i,num=0,r= -1;
 616         unsigned char *p;
 617         unsigned char *buf=NULL;
 618         BN_CTX *ctx=NULL;
 619
 620         if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
 621                 {
 622                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
 623                 return -1;
 624                 }
 625
 626         if (BN_ucmp(rsa->n, rsa->e) <= 0)
 627                 {
 628                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
 629                 return -1;
 630                 }
 631
 632         /* for large moduli, enforce exponent limit */
 633         if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
 634                 {
 635                 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
 636                         {
 637                         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
 638                         return -1;
 639                         }
 640                 }
 641
 642         if((ctx = BN_CTX_new()) == NULL) goto err;
 643         BN_CTX_start(ctx);
 644         f = BN_CTX_get(ctx);
 645         ret = BN_CTX_get(ctx);
 646         num=BN_num_bytes(rsa->n);
 647         buf = OPENSSL_malloc(num);
 648         if(!f || !ret || !buf)
 649                 {
 650                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
 651                 goto err;
 652                 }
 653
 654         /* This check was for equality but PGP does evil things
 655          * and chops off the top '0' bytes */
 656         if (flen > num)
 657                 {
 658                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 659                 goto err;
 660                 }
 661
 662         if (BN_bin2bn(from,flen,f) == NULL) goto err;
 663
 664         if (BN_ucmp(f, rsa->n) >= 0)
 665                 {
 666                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 667                 goto err;
 668                 }
 669
 670         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 671                 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 672                         goto err;
 673
 674         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 675                 rsa->_method_mod_n)) goto err;
 676
 677         if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12))
 678                 BN_sub(ret, rsa->n, ret);
 679
 680         p=buf;
 681         i=BN_bn2bin(ret,p);
 682
 683         switch (padding)
 684                 {
 685         case RSA_PKCS1_PADDING:
 686                 r=RSA_padding_check_PKCS1_type_1(to,num,buf,i,num);
 687                 break;
 688         case RSA_X931_PADDING:
 689                 r=RSA_padding_check_X931(to,num,buf,i,num);
 690                 break;
 691         case RSA_NO_PADDING:
 692                 r=RSA_padding_check_none(to,num,buf,i,num);
 693                 break;
 694         default:
 695                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 696                 goto err;
 697                 }
 698         if (r < 0)
 699                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 700
 701 err:
 702         if (ctx != NULL)
 703                 {
 704                 BN_CTX_end(ctx);
 705                 BN_CTX_free(ctx);
 706                 }
 707         if (buf != NULL)
 708                 {
 709                 OPENSSL_cleanse(buf,num);
 710                 OPENSSL_free(buf);
 711                 }
 712         return(r);
 713         }
 714
 715 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 716         {
 717         BIGNUM *r1,*m1,*vrfy;
 718         BIGNUM local_dmp1,local_dmq1,local_c,local_r1;
 719         BIGNUM *dmp1,*dmq1,*c,*pr1;
 720         int ret=0;
 721
 722         BN_CTX_start(ctx);
 723         r1 = BN_CTX_get(ctx);
 724         m1 = BN_CTX_get(ctx);
 725         vrfy = BN_CTX_get(ctx);
 726
 727         {
 728                 BIGNUM local_p, local_q;
 729                 BIGNUM *p = NULL, *q = NULL;
 730
 731                 /* Make sure BN_mod_inverse in Montgomery intialization uses the
 732                  * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
 733                  */
 734                 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 735                         {
 736                         BN_init(&local_p);
 737                         p = &local_p;
 738                         BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
 739
 740                         BN_init(&local_q);
 741                         q = &local_q;
 742                         BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
 743                         }
 744                 else
 745                         {
 746                         p = rsa->p;
 747                         q = rsa->q;
 748                         }
 749
 750                 if (rsa->flags & RSA_FLAG_CACHE_PRIVATE)
 751                         {
 752                         if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx))
 753                                 goto err;
 754                         if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q, CRYPTO_LOCK_RSA, q, ctx))
 755                                 goto err;
 756                         }
 757         }
 758
 759         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 760                 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 761                         goto err;
 762
 763         /* compute I mod q */
 764         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 765                 {
 766                 c = &local_c;
 767                 BN_with_flags(c, I, BN_FLG_CONSTTIME);
 768                 if (!BN_mod(r1,c,rsa->q,ctx)) goto err;
 769                 }
 770         else
 771                 {
 772                 if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
 773                 }
 774
 775         /* compute r1^dmq1 mod q */
 776         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 777                 {
 778                 dmq1 = &local_dmq1;
 779                 BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
 780                 }
 781         else
 782                 dmq1 = rsa->dmq1;
 783         if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
 784                 rsa->_method_mod_q)) goto err;
 785
 786         /* compute I mod p */
 787         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 788                 {
 789                 c = &local_c;
 790                 BN_with_flags(c, I, BN_FLG_CONSTTIME);
 791                 if (!BN_mod(r1,c,rsa->p,ctx)) goto err;
 792                 }
 793         else
 794                 {
 795                 if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
 796                 }
 797
 798         /* compute r1^dmp1 mod p */
 799         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 800                 {
 801                 dmp1 = &local_dmp1;
 802                 BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
 803                 }
 804         else
 805                 dmp1 = rsa->dmp1;
 806         if (!rsa->meth->bn_mod_exp(r0,r1,dmp1,rsa->p,ctx,
 807                 rsa->_method_mod_p)) goto err;
 808
 809         if (!BN_sub(r0,r0,m1)) goto err;
 810         /* This will help stop the size of r0 increasing, which does
 811          * affect the multiply if it optimised for a power of 2 size */
 812         if (BN_is_negative(r0))
 813                 if (!BN_add(r0,r0,rsa->p)) goto err;
 814
 815         if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
 816
 817         /* Turn BN_FLG_CONSTTIME flag on before division operation */
 818         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 819                 {
 820                 pr1 = &local_r1;
 821                 BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
 822                 }
 823         else
 824                 pr1 = r1;
 825         if (!BN_mod(r0,pr1,rsa->p,ctx)) goto err;
 826
 827         /* If p < q it is occasionally possible for the correction of
 828          * adding 'p' if r0 is negative above to leave the result still
 829          * negative. This can break the private key operations: the following
 830          * second correction should *always* correct this rare occurrence.
 831          * This will *never* happen with OpenSSL generated keys because
 832          * they ensure p > q [steve]
 833          */
 834         if (BN_is_negative(r0))
 835                 if (!BN_add(r0,r0,rsa->p)) goto err;
 836         if (!BN_mul(r1,r0,rsa->q,ctx)) goto err;
 837         if (!BN_add(r0,r1,m1)) goto err;
 838
 839         if (rsa->e && rsa->n)
 840                 {
 841                 if (!rsa->meth->bn_mod_exp(vrfy,r0,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err;
 842                 /* If 'I' was greater than (or equal to) rsa->n, the operation
 843                  * will be equivalent to using 'I mod n'. However, the result of
 844                  * the verify will *always* be less than 'n' so we don't check
 845                  * for absolute equality, just congruency. */
 846                 if (!BN_sub(vrfy, vrfy, I)) goto err;
 847                 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) goto err;
 848                 if (BN_is_negative(vrfy))
 849                         if (!BN_add(vrfy, vrfy, rsa->n)) goto err;
 850                 if (!BN_is_zero(vrfy))
 851                         {
 852                         /* 'I' and 'vrfy' aren't congruent mod n. Don't leak
 853                          * miscalculated CRT output, just do a raw (slower)
 854                          * mod_exp and return that instead. */
 855
 856                         BIGNUM local_d;
 857                         BIGNUM *d = NULL;
 858
 859                         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 860                                 {
 861                                 d = &local_d;
 862                                 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 863                                 }
 864                         else
 865                                 d = rsa->d;
 866                         if (!rsa->meth->bn_mod_exp(r0,I,d,rsa->n,ctx,
 867                                                    rsa->_method_mod_n)) goto err;
 868                         }
 869                 }
 870         ret=1;
 871 err:
 872         BN_CTX_end(ctx);
 873         return(ret);
 874         }
 875
 876 static int RSA_eay_init(RSA *rsa)
 877         {
 878         rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
 879         return(1);
 880         }
 881
 882 static int RSA_eay_finish(RSA *rsa)
 883         {
 884         if (rsa->_method_mod_n != NULL)
 885                 BN_MONT_CTX_free(rsa->_method_mod_n);
 886         if (rsa->_method_mod_p != NULL)
 887                 BN_MONT_CTX_free(rsa->_method_mod_p);
 888         if (rsa->_method_mod_q != NULL)
 889                 BN_MONT_CTX_free(rsa->_method_mod_q);
 890         return(1);
 891         }
 892
 893 #endif