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 /* Usage example;
 154  *    MONT_HELPER(rsa->_method_mod_p, bn_ctx, rsa->p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 155  */
 156 #define MONT_HELPER(method_mod, ctx, m, pre_cond, err_instr) \
 157         if ((pre_cond) && ((method_mod) == NULL) && \
 158                         !BN_MONT_CTX_set_locked(&(method_mod), \
 159                                 CRYPTO_LOCK_RSA, \
 160                                 (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 (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
 172                 {
 173                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
 174                 return -1;
 175                 }
 176
 177         if (BN_ucmp(rsa->n, rsa->e) <= 0)
 178                 {
 179                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 180                 return -1;
 181                 }
 182
 183         /* for large moduli, enforce exponent limit */
 184         if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
 185                 {
 186                 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
 187                         {
 188                         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 189                         return -1;
 190                         }
 191                 }
 192
 193         if ((ctx=BN_CTX_new()) == NULL) goto err;
 194         BN_CTX_start(ctx);
 195         f = BN_CTX_get(ctx);
 196         ret = BN_CTX_get(ctx);
 197         num=BN_num_bytes(rsa->n);
 198         buf = OPENSSL_malloc(num);
 199         if (!f || !ret || !buf)
 200                 {
 201                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
 202                 goto err;
 203                 }
 204
 205         switch (padding)
 206                 {
 207         case RSA_PKCS1_PADDING:
 208                 i=RSA_padding_add_PKCS1_type_2(buf,num,from,flen);
 209                 break;
 210 #ifndef OPENSSL_NO_SHA
 211         case RSA_PKCS1_OAEP_PADDING:
 212                 i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
 213                 break;
 214 #endif
 215         case RSA_SSLV23_PADDING:
 216                 i=RSA_padding_add_SSLv23(buf,num,from,flen);
 217                 break;
 218         case RSA_NO_PADDING:
 219                 i=RSA_padding_add_none(buf,num,from,flen);
 220                 break;
 221         default:
 222                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 223                 goto err;
 224                 }
 225         if (i <= 0) goto err;
 226
 227         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 228
 229         if (BN_ucmp(f, rsa->n) >= 0)
 230                 {
 231                 /* usually the padding functions would catch this */
 232                 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 233                 goto err;
 234                 }
 235
 236         MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 237
 238         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 239                 rsa->_method_mod_n)) goto err;
 240
 241         /* put in leading 0 bytes if the number is less than the
 242          * length of the modulus */
 243         j=BN_num_bytes(ret);
 244         i=BN_bn2bin(ret,&(to[num-j]));
 245         for (k=0; k<(num-i); k++)
 246                 to[k]=0;
 247
 248         r=num;
 249 err:
 250         if (ctx != NULL)
 251                 {
 252                 BN_CTX_end(ctx);
 253                 BN_CTX_free(ctx);
 254                 }
 255         if (buf != NULL)
 256                 {
 257                 OPENSSL_cleanse(buf,num);
 258                 OPENSSL_free(buf);
 259                 }
 260         return(r);
 261         }
 262
 263 static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
 264 {
 265         BN_BLINDING *ret;
 266         int got_write_lock = 0;
 267         CRYPTO_THREADID cur;
 268
 269         CRYPTO_r_lock(CRYPTO_LOCK_RSA);
 270
 271         if (rsa->blinding == NULL)
 272                 {
 273                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 274                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 275                 got_write_lock = 1;
 276
 277                 if (rsa->blinding == NULL)
 278                         rsa->blinding = RSA_setup_blinding(rsa, ctx);
 279                 }
 280
 281         ret = rsa->blinding;
 282         if (ret == NULL)
 283                 goto err;
 284
 285         CRYPTO_THREADID_current(&cur);
 286         if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret)))
 287                 {
 288                 /* rsa->blinding is ours! */
 289
 290                 *local = 1;
 291                 }
 292         else
 293                 {
 294                 /* resort to rsa->mt_blinding instead */
 295
 296                 *local = 0; /* instructs rsa_blinding_convert(), rsa_blinding_invert()
 297                              * that the BN_BLINDING is shared, meaning that accesses
 298                              * require locks, and that the blinding factor must be
 299                              * stored outside the BN_BLINDING
 300                              */
 301
 302                 if (rsa->mt_blinding == NULL)
 303                         {
 304                         if (!got_write_lock)
 305                                 {
 306                                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 307                                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 308                                 got_write_lock = 1;
 309                                 }
 310
 311                         if (rsa->mt_blinding == NULL)
 312                                 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
 313                         }
 314                 ret = rsa->mt_blinding;
 315                 }
 316
 317  err:
 318         if (got_write_lock)
 319                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 320         else
 321                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 322         return ret;
 323 }
 324
 325 static int rsa_blinding_convert(BN_BLINDING *b, int local, BIGNUM *f,
 326         BIGNUM *r, BN_CTX *ctx)
 327 {
 328         if (local)
 329                 return BN_BLINDING_convert_ex(f, NULL, b, ctx);
 330         else
 331                 {
 332                 int ret;
 333                 CRYPTO_r_lock(CRYPTO_LOCK_RSA_BLINDING);
 334                 ret = BN_BLINDING_convert_ex(f, r, b, ctx);
 335                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA_BLINDING);
 336                 return ret;
 337                 }
 338 }
 339
 340 static int rsa_blinding_invert(BN_BLINDING *b, int local, BIGNUM *f,
 341         BIGNUM *r, BN_CTX *ctx)
 342 {
 343         if (local)
 344                 return BN_BLINDING_invert_ex(f, NULL, b, ctx);
 345         else
 346                 {
 347                 int ret;
 348                 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
 349                 ret = BN_BLINDING_invert_ex(f, r, b, ctx);
 350                 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
 351                 return ret;
 352                 }
 353 }
 354
 355 /* signing */
 356 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 357              unsigned char *to, RSA *rsa, int padding)
 358         {
 359         BIGNUM *f, *ret, *br, *res;
 360         int i,j,k,num=0,r= -1;
 361         unsigned char *buf=NULL;
 362         BN_CTX *ctx=NULL;
 363         int local_blinding = 0;
 364         BN_BLINDING *blinding = NULL;
 365
 366         if ((ctx=BN_CTX_new()) == NULL) goto err;
 367         BN_CTX_start(ctx);
 368         f   = BN_CTX_get(ctx);
 369         br  = BN_CTX_get(ctx);
 370         ret = BN_CTX_get(ctx);
 371         num = BN_num_bytes(rsa->n);
 372         buf = OPENSSL_malloc(num);
 373         if(!f || !ret || !buf)
 374                 {
 375                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
 376                 goto err;
 377                 }
 378
 379         switch (padding)
 380                 {
 381         case RSA_PKCS1_PADDING:
 382                 i=RSA_padding_add_PKCS1_type_1(buf,num,from,flen);
 383                 break;
 384         case RSA_X931_PADDING:
 385                 i=RSA_padding_add_X931(buf,num,from,flen);
 386                 break;
 387         case RSA_NO_PADDING:
 388                 i=RSA_padding_add_none(buf,num,from,flen);
 389                 break;
 390         case RSA_SSLV23_PADDING:
 391         default:
 392                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 393                 goto err;
 394                 }
 395         if (i <= 0) goto err;
 396
 397         if (BN_bin2bn(buf,num,f) == NULL) goto err;
 398
 399         if (BN_ucmp(f, rsa->n) >= 0)
 400                 {
 401                 /* usually the padding functions would catch this */
 402                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 403                 goto err;
 404                 }
 405
 406         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 407                 {
 408                 blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 409                 if (blinding == NULL)
 410                         {
 411                         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
 412                         goto err;
 413                         }
 414                 }
 415
 416         if (blinding != NULL)
 417                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 418                         goto err;
 419
 420         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 421                 ((rsa->p != NULL) &&
 422                 (rsa->q != NULL) &&
 423                 (rsa->dmp1 != NULL) &&
 424                 (rsa->dmq1 != NULL) &&
 425                 (rsa->iqmp != NULL)) )
 426                 {
 427                 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
 428                 }
 429         else
 430                 {
 431                 BIGNUM local_d;
 432                 BIGNUM *d = NULL;
 433
 434                 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 435                         {
 436                         BN_init(&local_d);
 437                         d = &local_d;
 438                         BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 439                         }
 440                 else
 441                         d= rsa->d;
 442
 443                 MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 444
 445                 if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 446                                 rsa->_method_mod_n)) goto err;
 447                 }
 448
 449         if (blinding)
 450                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 451                         goto err;
 452
 453         if (padding == RSA_X931_PADDING)
 454                 {
 455                 BN_sub(f, rsa->n, ret);
 456                 if (BN_cmp(ret, f))
 457                         res = f;
 458                 else
 459                         res = ret;
 460                 }
 461         else
 462                 res = ret;
 463
 464         /* put in leading 0 bytes if the number is less than the
 465          * length of the modulus */
 466         j=BN_num_bytes(res);
 467         i=BN_bn2bin(res,&(to[num-j]));
 468         for (k=0; k<(num-i); k++)
 469                 to[k]=0;
 470
 471         r=num;
 472 err:
 473         if (ctx != NULL)
 474                 {
 475                 BN_CTX_end(ctx);
 476                 BN_CTX_free(ctx);
 477                 }
 478         if (buf != NULL)
 479                 {
 480                 OPENSSL_cleanse(buf,num);
 481                 OPENSSL_free(buf);
 482                 }
 483         return(r);
 484         }
 485
 486 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 487              unsigned char *to, RSA *rsa, int padding)
 488         {
 489         BIGNUM *f, *ret, *br;
 490         int j,num=0,r= -1;
 491         unsigned char *p;
 492         unsigned char *buf=NULL;
 493         BN_CTX *ctx=NULL;
 494         int local_blinding = 0;
 495         BN_BLINDING *blinding = NULL;
 496
 497         if((ctx = BN_CTX_new()) == NULL) goto err;
 498         BN_CTX_start(ctx);
 499         f   = BN_CTX_get(ctx);
 500         br  = BN_CTX_get(ctx);
 501         ret = BN_CTX_get(ctx);
 502         num = BN_num_bytes(rsa->n);
 503         buf = OPENSSL_malloc(num);
 504         if(!f || !ret || !buf)
 505                 {
 506                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
 507                 goto err;
 508                 }
 509
 510         /* This check was for equality but PGP does evil things
 511          * and chops off the top '0' bytes */
 512         if (flen > num)
 513                 {
 514                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 515                 goto err;
 516                 }
 517
 518         /* make data into a big number */
 519         if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;
 520
 521         if (BN_ucmp(f, rsa->n) >= 0)
 522                 {
 523                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 524                 goto err;
 525                 }
 526
 527         if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
 528                 {
 529                 blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 530                 if (blinding == NULL)
 531                         {
 532                         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
 533                         goto err;
 534                         }
 535                 }
 536
 537         if (blinding != NULL)
 538                 if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
 539                         goto err;
 540
 541         /* do the decrypt */
 542         if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 543                 ((rsa->p != NULL) &&
 544                 (rsa->q != NULL) &&
 545                 (rsa->dmp1 != NULL) &&
 546                 (rsa->dmq1 != NULL) &&
 547                 (rsa->iqmp != NULL)) )
 548                 {
 549                 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
 550                 }
 551         else
 552                 {
 553                 BIGNUM local_d;
 554                 BIGNUM *d = NULL;
 555
 556                 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 557                         {
 558                         d = &local_d;
 559                         BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 560                         }
 561                 else
 562                         d = rsa->d;
 563
 564                 MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 565                 if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 566                                 rsa->_method_mod_n))
 567                   goto err;
 568                 }
 569
 570         if (blinding)
 571                 if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
 572                         goto err;
 573
 574         p=buf;
 575         j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */
 576
 577         switch (padding)
 578                 {
 579         case RSA_PKCS1_PADDING:
 580                 r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
 581                 break;
 582 #ifndef OPENSSL_NO_SHA
 583         case RSA_PKCS1_OAEP_PADDING:
 584                 r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
 585                 break;
 586 #endif
 587         case RSA_SSLV23_PADDING:
 588                 r=RSA_padding_check_SSLv23(to,num,buf,j,num);
 589                 break;
 590         case RSA_NO_PADDING:
 591                 r=RSA_padding_check_none(to,num,buf,j,num);
 592                 break;
 593         default:
 594                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 595                 goto err;
 596                 }
 597         if (r < 0)
 598                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 599
 600 err:
 601         if (ctx != NULL)
 602                 {
 603                 BN_CTX_end(ctx);
 604                 BN_CTX_free(ctx);
 605                 }
 606         if (buf != NULL)
 607                 {
 608                 OPENSSL_cleanse(buf,num);
 609                 OPENSSL_free(buf);
 610                 }
 611         return(r);
 612         }
 613
 614 /* signature verification */
 615 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 616              unsigned char *to, RSA *rsa, int padding)
 617         {
 618         BIGNUM *f,*ret;
 619         int i,num=0,r= -1;
 620         unsigned char *p;
 621         unsigned char *buf=NULL;
 622         BN_CTX *ctx=NULL;
 623
 624         if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
 625                 {
 626                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
 627                 return -1;
 628                 }
 629
 630         if (BN_ucmp(rsa->n, rsa->e) <= 0)
 631                 {
 632                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
 633                 return -1;
 634                 }
 635
 636         /* for large moduli, enforce exponent limit */
 637         if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
 638                 {
 639                 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
 640                         {
 641                         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
 642                         return -1;
 643                         }
 644                 }
 645
 646         if((ctx = BN_CTX_new()) == NULL) goto err;
 647         BN_CTX_start(ctx);
 648         f = BN_CTX_get(ctx);
 649         ret = BN_CTX_get(ctx);
 650         num=BN_num_bytes(rsa->n);
 651         buf = OPENSSL_malloc(num);
 652         if(!f || !ret || !buf)
 653                 {
 654                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
 655                 goto err;
 656                 }
 657
 658         /* This check was for equality but PGP does evil things
 659          * and chops off the top '0' bytes */
 660         if (flen > num)
 661                 {
 662                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
 663                 goto err;
 664                 }
 665
 666         if (BN_bin2bn(from,flen,f) == NULL) goto err;
 667
 668         if (BN_ucmp(f, rsa->n) >= 0)
 669                 {
 670                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 671                 goto err;
 672                 }
 673
 674         MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 675
 676         if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 677                 rsa->_method_mod_n)) goto err;
 678
 679         if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12))
 680                 BN_sub(ret, rsa->n, ret);
 681
 682         p=buf;
 683         i=BN_bn2bin(ret,p);
 684
 685         switch (padding)
 686                 {
 687         case RSA_PKCS1_PADDING:
 688                 r=RSA_padding_check_PKCS1_type_1(to,num,buf,i,num);
 689                 break;
 690         case RSA_X931_PADDING:
 691                 r=RSA_padding_check_X931(to,num,buf,i,num);
 692                 break;
 693         case RSA_NO_PADDING:
 694                 r=RSA_padding_check_none(to,num,buf,i,num);
 695                 break;
 696         default:
 697                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
 698                 goto err;
 699                 }
 700         if (r < 0)
 701                 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 702
 703 err:
 704         if (ctx != NULL)
 705                 {
 706                 BN_CTX_end(ctx);
 707                 BN_CTX_free(ctx);
 708                 }
 709         if (buf != NULL)
 710                 {
 711                 OPENSSL_cleanse(buf,num);
 712                 OPENSSL_free(buf);
 713                 }
 714         return(r);
 715         }
 716
 717 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 718         {
 719         BIGNUM *r1,*m1,*vrfy;
 720         BIGNUM local_dmp1,local_dmq1,local_c,local_r1;
 721         BIGNUM *dmp1,*dmq1,*c,*pr1;
 722         int ret=0;
 723
 724         BN_CTX_start(ctx);
 725         r1 = BN_CTX_get(ctx);
 726         m1 = BN_CTX_get(ctx);
 727         vrfy = BN_CTX_get(ctx);
 728
 729         {
 730                 BIGNUM local_p, local_q;
 731                 BIGNUM *p = NULL, *q = NULL;
 732
 733                 /* Make sure BN_mod_inverse in Montgomery intialization uses the
 734                  * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
 735                  */
 736                 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 737                         {
 738                         BN_init(&local_p);
 739                         p = &local_p;
 740                         BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
 741
 742                         BN_init(&local_q);
 743                         q = &local_q;
 744                         BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
 745                         }
 746                 else
 747                         {
 748                         p = rsa->p;
 749                         q = rsa->q;
 750                         }
 751
 752                 MONT_HELPER(rsa->_method_mod_p, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 753                 MONT_HELPER(rsa->_method_mod_q, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 754         }
 755
 756         MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 757
 758         /* compute I mod q */
 759         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 760                 {
 761                 c = &local_c;
 762                 BN_with_flags(c, I, BN_FLG_CONSTTIME);
 763                 if (!BN_mod(r1,c,rsa->q,ctx)) goto err;
 764                 }
 765         else
 766                 {
 767                 if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
 768                 }
 769
 770         /* compute r1^dmq1 mod q */
 771         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 772                 {
 773                 dmq1 = &local_dmq1;
 774                 BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
 775                 }
 776         else
 777                 dmq1 = rsa->dmq1;
 778         if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
 779                 rsa->_method_mod_q)) goto err;
 780
 781         /* compute I mod p */
 782         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 783                 {
 784                 c = &local_c;
 785                 BN_with_flags(c, I, BN_FLG_CONSTTIME);
 786                 if (!BN_mod(r1,c,rsa->p,ctx)) goto err;
 787                 }
 788         else
 789                 {
 790                 if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
 791                 }
 792
 793         /* compute r1^dmp1 mod p */
 794         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 795                 {
 796                 dmp1 = &local_dmp1;
 797                 BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
 798                 }
 799         else
 800                 dmp1 = rsa->dmp1;
 801         if (!rsa->meth->bn_mod_exp(r0,r1,dmp1,rsa->p,ctx,
 802                 rsa->_method_mod_p)) goto err;
 803
 804         if (!BN_sub(r0,r0,m1)) goto err;
 805         /* This will help stop the size of r0 increasing, which does
 806          * affect the multiply if it optimised for a power of 2 size */
 807         if (BN_is_negative(r0))
 808                 if (!BN_add(r0,r0,rsa->p)) goto err;
 809
 810         if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
 811
 812         /* Turn BN_FLG_CONSTTIME flag on before division operation */
 813         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 814                 {
 815                 pr1 = &local_r1;
 816                 BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
 817                 }
 818         else
 819                 pr1 = r1;
 820         if (!BN_mod(r0,pr1,rsa->p,ctx)) goto err;
 821
 822         /* If p < q it is occasionally possible for the correction of
 823          * adding 'p' if r0 is negative above to leave the result still
 824          * negative. This can break the private key operations: the following
 825          * second correction should *always* correct this rare occurrence.
 826          * This will *never* happen with OpenSSL generated keys because
 827          * they ensure p > q [steve]
 828          */
 829         if (BN_is_negative(r0))
 830                 if (!BN_add(r0,r0,rsa->p)) goto err;
 831         if (!BN_mul(r1,r0,rsa->q,ctx)) goto err;
 832         if (!BN_add(r0,r1,m1)) goto err;
 833
 834         if (rsa->e && rsa->n)
 835                 {
 836                 if (!rsa->meth->bn_mod_exp(vrfy,r0,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err;
 837                 /* If 'I' was greater than (or equal to) rsa->n, the operation
 838                  * will be equivalent to using 'I mod n'. However, the result of
 839                  * the verify will *always* be less than 'n' so we don't check
 840                  * for absolute equality, just congruency. */
 841                 if (!BN_sub(vrfy, vrfy, I)) goto err;
 842                 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) goto err;
 843                 if (BN_is_negative(vrfy))
 844                         if (!BN_add(vrfy, vrfy, rsa->n)) goto err;
 845                 if (!BN_is_zero(vrfy))
 846                         {
 847                         /* 'I' and 'vrfy' aren't congruent mod n. Don't leak
 848                          * miscalculated CRT output, just do a raw (slower)
 849                          * mod_exp and return that instead. */
 850
 851                         BIGNUM local_d;
 852                         BIGNUM *d = NULL;
 853
 854                         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
 855                                 {
 856                                 d = &local_d;
 857                                 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 858                                 }
 859                         else
 860                                 d = rsa->d;
 861                         if (!rsa->meth->bn_mod_exp(r0,I,d,rsa->n,ctx,
 862                                                    rsa->_method_mod_n)) goto err;
 863                         }
 864                 }
 865         ret=1;
 866 err:
 867         BN_CTX_end(ctx);
 868         return(ret);
 869         }
 870
 871 static int RSA_eay_init(RSA *rsa)
 872         {
 873         rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
 874         return(1);
 875         }
 876
 877 static int RSA_eay_finish(RSA *rsa)
 878         {
 879         if (rsa->_method_mod_n != NULL)
 880                 BN_MONT_CTX_free(rsa->_method_mod_n);
 881         if (rsa->_method_mod_p != NULL)
 882                 BN_MONT_CTX_free(rsa->_method_mod_p);
 883         if (rsa->_method_mod_q != NULL)
 884                 BN_MONT_CTX_free(rsa->_method_mod_q);
 885         return(1);
 886         }
 887
 888 #endif