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 #if !defined(RSA_NULL) && !defined(OPENSSL_FIPS)
 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,
 129                            BN_CTX *ctx);
 130 static int RSA_eay_init(RSA *rsa);
 131 static int RSA_eay_finish(RSA *rsa);
 132 static RSA_METHOD rsa_pkcs1_eay_meth = {
 133     "Eric Young's PKCS#1 RSA",
 134     RSA_eay_public_encrypt,
 135     RSA_eay_public_decrypt,     /* signature verification */
 136     RSA_eay_private_encrypt,    /* signing */
 137     RSA_eay_private_decrypt,
 138     RSA_eay_mod_exp,
 139     BN_mod_exp_mont,            /* XXX probably we should not use Montgomery
 140                                  * if e == 3 */
 141     RSA_eay_init,
 142     RSA_eay_finish,
 143     0,                          /* flags */
 144     NULL,
 145     0,                          /* rsa_sign */
 146     0,                          /* rsa_verify */
 147     NULL                        /* rsa_keygen */
 148 };
 149
 150 const RSA_METHOD *RSA_PKCS1_SSLeay(void)
 151 {
 152     return (&rsa_pkcs1_eay_meth);
 153 }
 154
 155 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 156                                   unsigned char *to, RSA *rsa, int padding)
 157 {
 158     BIGNUM *f, *ret;
 159     int i, j, k, num = 0, r = -1;
 160     unsigned char *buf = NULL;
 161     BN_CTX *ctx = NULL;
 162
 163     if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
 164         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
 165         return -1;
 166     }
 167
 168     if (BN_ucmp(rsa->n, rsa->e) <= 0) {
 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         if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
 176             RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 177             return -1;
 178         }
 179     }
 180
 181     if ((ctx = BN_CTX_new()) == NULL)
 182         goto err;
 183     BN_CTX_start(ctx);
 184     f = BN_CTX_get(ctx);
 185     ret = BN_CTX_get(ctx);
 186     num = BN_num_bytes(rsa->n);
 187     buf = OPENSSL_malloc(num);
 188     if (!f || !ret || !buf) {
 189         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE);
 190         goto err;
 191     }
 192
 193     switch (padding) {
 194     case RSA_PKCS1_PADDING:
 195         i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen);
 196         break;
 197 # ifndef OPENSSL_NO_SHA
 198     case RSA_PKCS1_OAEP_PADDING:
 199         i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0);
 200         break;
 201 # endif
 202     case RSA_SSLV23_PADDING:
 203         i = RSA_padding_add_SSLv23(buf, num, from, flen);
 204         break;
 205     case RSA_NO_PADDING:
 206         i = RSA_padding_add_none(buf, num, from, flen);
 207         break;
 208     default:
 209         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 210         goto err;
 211     }
 212     if (i <= 0)
 213         goto err;
 214
 215     if (BN_bin2bn(buf, num, f) == NULL)
 216         goto err;
 217
 218     if (BN_ucmp(f, rsa->n) >= 0) {
 219         /* usually the padding functions would catch this */
 220         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,
 221                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 222         goto err;
 223     }
 224
 225     if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 226         if (!BN_MONT_CTX_set_locked
 227             (&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))
 232         goto err;
 233
 234     /*
 235      * put in leading 0 bytes if the number is less than the length of the
 236      * modulus
 237      */
 238     j = BN_num_bytes(ret);
 239     i = BN_bn2bin(ret, &(to[num - j]));
 240     for (k = 0; k < (num - i); k++)
 241         to[k] = 0;
 242
 243     r = num;
 244  err:
 245     if (ctx != NULL) {
 246         BN_CTX_end(ctx);
 247         BN_CTX_free(ctx);
 248     }
 249     if (buf != NULL) {
 250         OPENSSL_cleanse(buf, num);
 251         OPENSSL_free(buf);
 252     }
 253     return (r);
 254 }
 255
 256 static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
 257 {
 258     BN_BLINDING *ret;
 259     int got_write_lock = 0;
 260
 261     CRYPTO_r_lock(CRYPTO_LOCK_RSA);
 262
 263     if (rsa->blinding == NULL) {
 264         CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 265         CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 266         got_write_lock = 1;
 267
 268         if (rsa->blinding == NULL)
 269             rsa->blinding = RSA_setup_blinding(rsa, ctx);
 270     }
 271
 272     ret = rsa->blinding;
 273     if (ret == NULL)
 274         goto err;
 275
 276     if (BN_BLINDING_get_thread_id(ret) == CRYPTO_thread_id()) {
 277         /* rsa->blinding is ours! */
 278
 279         *local = 1;
 280     } else {
 281         /* resort to rsa->mt_blinding instead */
 282
 283         /*
 284          * instructs rsa_blinding_convert(), rsa_blinding_invert() that the
 285          * BN_BLINDING is shared, meaning that accesses require locks, and
 286          * that the blinding factor must be stored outside the BN_BLINDING
 287          */
 288         *local = 0;
 289
 290         if (rsa->mt_blinding == NULL) {
 291             if (!got_write_lock) {
 292                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 293                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 294                 got_write_lock = 1;
 295             }
 296
 297             if (rsa->mt_blinding == NULL)
 298                 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
 299         }
 300         ret = rsa->mt_blinding;
 301     }
 302
 303  err:
 304     if (got_write_lock)
 305         CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 306     else
 307         CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 308     return ret;
 309 }
 310
 311 static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
 312                                 BN_CTX *ctx)
 313 {
 314     if (unblind == NULL)
 315         /*
 316          * Local blinding: store the unblinding factor in BN_BLINDING.
 317          */
 318         return BN_BLINDING_convert_ex(f, NULL, b, ctx);
 319     else {
 320         /*
 321          * Shared blinding: store the unblinding factor outside BN_BLINDING.
 322          */
 323         int ret;
 324         CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
 325         ret = BN_BLINDING_convert_ex(f, unblind, b, ctx);
 326         CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
 327         return ret;
 328     }
 329 }
 330
 331 static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
 332                                BN_CTX *ctx)
 333 {
 334     /*
 335      * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex
 336      * will use the unblinding factor stored in BN_BLINDING. If BN_BLINDING
 337      * is shared between threads, unblind must be non-null:
 338      * BN_BLINDING_invert_ex will then use the local unblinding factor, and
 339      * will only read the modulus from BN_BLINDING. In both cases it's safe
 340      * to access the blinding without a lock.
 341      */
 342     return BN_BLINDING_invert_ex(f, unblind, b, ctx);
 343 }
 344
 345 /* signing */
 346 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 347                                    unsigned char *to, RSA *rsa, int padding)
 348 {
 349     BIGNUM *f, *ret, *res;
 350     int i, j, k, num = 0, r = -1;
 351     unsigned char *buf = NULL;
 352     BN_CTX *ctx = NULL;
 353     int local_blinding = 0;
 354     /*
 355      * Used only if the blinding structure is shared. A non-NULL unblind
 356      * instructs rsa_blinding_convert() and rsa_blinding_invert() to store
 357      * the unblinding factor outside the blinding structure.
 358      */
 359     BIGNUM *unblind = NULL;
 360     BN_BLINDING *blinding = NULL;
 361
 362     if ((ctx = BN_CTX_new()) == NULL)
 363         goto err;
 364     BN_CTX_start(ctx);
 365     f = BN_CTX_get(ctx);
 366     ret = BN_CTX_get(ctx);
 367     num = BN_num_bytes(rsa->n);
 368     buf = OPENSSL_malloc(num);
 369     if (!f || !ret || !buf) {
 370         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
 371         goto err;
 372     }
 373
 374     switch (padding) {
 375     case RSA_PKCS1_PADDING:
 376         i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen);
 377         break;
 378     case RSA_X931_PADDING:
 379         i = RSA_padding_add_X931(buf, num, from, flen);
 380         break;
 381     case RSA_NO_PADDING:
 382         i = RSA_padding_add_none(buf, num, from, flen);
 383         break;
 384     case RSA_SSLV23_PADDING:
 385     default:
 386         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 387         goto err;
 388     }
 389     if (i <= 0)
 390         goto err;
 391
 392     if (BN_bin2bn(buf, num, f) == NULL)
 393         goto err;
 394
 395     if (BN_ucmp(f, rsa->n) >= 0) {
 396         /* usually the padding functions would catch this */
 397         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,
 398                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 399         goto err;
 400     }
 401
 402     if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
 403         blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 404         if (blinding == NULL) {
 405             RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
 406             goto err;
 407         }
 408     }
 409
 410     if (blinding != NULL) {
 411         if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
 412             RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
 413             goto err;
 414         }
 415         if (!rsa_blinding_convert(blinding, f, unblind, ctx))
 416             goto err;
 417     }
 418
 419     if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
 420         ((rsa->p != NULL) &&
 421          (rsa->q != NULL) &&
 422          (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
 423         if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
 424             goto err;
 425     } else {
 426         BIGNUM local_d;
 427         BIGNUM *d = NULL;
 428
 429         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 430             BN_init(&local_d);
 431             d = &local_d;
 432             BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 433         } else
 434             d = rsa->d;
 435
 436         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 437             if (!BN_MONT_CTX_set_locked
 438                 (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 439                 goto err;
 440
 441         if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
 442                                    rsa->_method_mod_n))
 443             goto err;
 444     }
 445
 446     if (blinding)
 447         if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
 448             goto err;
 449
 450     if (padding == RSA_X931_PADDING) {
 451         BN_sub(f, rsa->n, ret);
 452         if (BN_cmp(ret, f) > 0)
 453             res = f;
 454         else
 455             res = ret;
 456     } else
 457         res = ret;
 458
 459     /*
 460      * put in leading 0 bytes if the number is less than the length of the
 461      * modulus
 462      */
 463     j = BN_num_bytes(res);
 464     i = BN_bn2bin(res, &(to[num - j]));
 465     for (k = 0; k < (num - i); k++)
 466         to[k] = 0;
 467
 468     r = num;
 469  err:
 470     if (ctx != NULL) {
 471         BN_CTX_end(ctx);
 472         BN_CTX_free(ctx);
 473     }
 474     if (buf != NULL) {
 475         OPENSSL_cleanse(buf, num);
 476         OPENSSL_free(buf);
 477     }
 478     return (r);
 479 }
 480
 481 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 482                                    unsigned char *to, RSA *rsa, int padding)
 483 {
 484     BIGNUM *f, *ret;
 485     int j, num = 0, r = -1;
 486     unsigned char *p;
 487     unsigned char *buf = NULL;
 488     BN_CTX *ctx = NULL;
 489     int local_blinding = 0;
 490     /*
 491      * Used only if the blinding structure is shared. A non-NULL unblind
 492      * instructs rsa_blinding_convert() and rsa_blinding_invert() to store
 493      * the unblinding factor outside the blinding structure.
 494      */
 495     BIGNUM *unblind = NULL;
 496     BN_BLINDING *blinding = NULL;
 497
 498     if ((ctx = BN_CTX_new()) == NULL)
 499         goto err;
 500     BN_CTX_start(ctx);
 501     f = BN_CTX_get(ctx);
 502     ret = BN_CTX_get(ctx);
 503     num = BN_num_bytes(rsa->n);
 504     buf = OPENSSL_malloc(num);
 505     if (!f || !ret || !buf) {
 506         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
 507         goto err;
 508     }
 509
 510     /*
 511      * This check was for equality but PGP does evil things and chops off the
 512      * top '0' bytes
 513      */
 514     if (flen > num) {
 515         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,
 516                RSA_R_DATA_GREATER_THAN_MOD_LEN);
 517         goto err;
 518     }
 519
 520     /* make data into a big number */
 521     if (BN_bin2bn(from, (int)flen, f) == NULL)
 522         goto err;
 523
 524     if (BN_ucmp(f, rsa->n) >= 0) {
 525         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,
 526                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 527         goto err;
 528     }
 529
 530     if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
 531         blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 532         if (blinding == NULL) {
 533             RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
 534             goto err;
 535         }
 536     }
 537
 538     if (blinding != NULL) {
 539         if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
 540             RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
 541             goto err;
 542         }
 543         if (!rsa_blinding_convert(blinding, f, unblind, ctx))
 544             goto err;
 545     }
 546
 547     /* do the decrypt */
 548     if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
 549         ((rsa->p != NULL) &&
 550          (rsa->q != NULL) &&
 551          (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
 552         if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
 553             goto err;
 554     } else {
 555         BIGNUM local_d;
 556         BIGNUM *d = NULL;
 557
 558         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 559             d = &local_d;
 560             BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 561         } else
 562             d = rsa->d;
 563
 564         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 565             if (!BN_MONT_CTX_set_locked
 566                 (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 567                 goto err;
 568         if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
 569                                    rsa->_method_mod_n))
 570             goto err;
 571     }
 572
 573     if (blinding)
 574         if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
 575             goto err;
 576
 577     p = buf;
 578     j = BN_bn2bin(ret, p);      /* j is only used with no-padding mode */
 579
 580     switch (padding) {
 581     case RSA_PKCS1_PADDING:
 582         r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num);
 583         break;
 584 # ifndef OPENSSL_NO_SHA
 585     case RSA_PKCS1_OAEP_PADDING:
 586         r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0);
 587         break;
 588 # endif
 589     case RSA_SSLV23_PADDING:
 590         r = RSA_padding_check_SSLv23(to, num, buf, j, num);
 591         break;
 592     case RSA_NO_PADDING:
 593         r = RSA_padding_check_none(to, num, buf, j, num);
 594         break;
 595     default:
 596         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 597         goto err;
 598     }
 599     if (r < 0)
 600         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
 601
 602  err:
 603     if (ctx != NULL) {
 604         BN_CTX_end(ctx);
 605         BN_CTX_free(ctx);
 606     }
 607     if (buf != NULL) {
 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         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
 626         return -1;
 627     }
 628
 629     if (BN_ucmp(rsa->n, rsa->e) <= 0) {
 630         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
 631         return -1;
 632     }
 633
 634     /* for large moduli, enforce exponent limit */
 635     if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) {
 636         if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
 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)
 643         goto err;
 644     BN_CTX_start(ctx);
 645     f = BN_CTX_get(ctx);
 646     ret = BN_CTX_get(ctx);
 647     num = BN_num_bytes(rsa->n);
 648     buf = OPENSSL_malloc(num);
 649     if (!f || !ret || !buf) {
 650         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE);
 651         goto err;
 652     }
 653
 654     /*
 655      * This check was for equality but PGP does evil things and chops off the
 656      * top '0' bytes
 657      */
 658     if (flen > num) {
 659         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_DATA_GREATER_THAN_MOD_LEN);
 660         goto err;
 661     }
 662
 663     if (BN_bin2bn(from, flen, f) == NULL)
 664         goto err;
 665
 666     if (BN_ucmp(f, rsa->n) >= 0) {
 667         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,
 668                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 669         goto err;
 670     }
 671
 672     if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 673         if (!BN_MONT_CTX_set_locked
 674             (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 675             goto err;
 676
 677     if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx,
 678                                rsa->_method_mod_n))
 679         goto err;
 680
 681     if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12))
 682         if (!BN_sub(ret, rsa->n, ret))
 683             goto err;
 684
 685     p = buf;
 686     i = BN_bn2bin(ret, p);
 687
 688     switch (padding) {
 689     case RSA_PKCS1_PADDING:
 690         r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num);
 691         break;
 692     case RSA_X931_PADDING:
 693         r = RSA_padding_check_X931(to, num, buf, i, num);
 694         break;
 695     case RSA_NO_PADDING:
 696         r = RSA_padding_check_none(to, num, buf, i, num);
 697         break;
 698     default:
 699         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 700         goto err;
 701     }
 702     if (r < 0)
 703         RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
 704
 705  err:
 706     if (ctx != NULL) {
 707         BN_CTX_end(ctx);
 708         BN_CTX_free(ctx);
 709     }
 710     if (buf != NULL) {
 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         /*
 734          * Make sure BN_mod_inverse in Montgomery intialization uses the
 735          * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
 736          */
 737         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 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         } else {
 746             p = rsa->p;
 747             q = rsa->q;
 748         }
 749
 750         if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
 751             if (!BN_MONT_CTX_set_locked
 752                 (&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx))
 753                 goto err;
 754             if (!BN_MONT_CTX_set_locked
 755                 (&rsa->_method_mod_q, CRYPTO_LOCK_RSA, q, ctx))
 756                 goto err;
 757         }
 758     }
 759
 760     if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 761         if (!BN_MONT_CTX_set_locked
 762             (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 763             goto err;
 764
 765     /* compute I mod q */
 766     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 767         c = &local_c;
 768         BN_with_flags(c, I, BN_FLG_CONSTTIME);
 769         if (!BN_mod(r1, c, rsa->q, ctx))
 770             goto err;
 771     } else {
 772         if (!BN_mod(r1, I, rsa->q, ctx))
 773             goto err;
 774     }
 775
 776     /* compute r1^dmq1 mod q */
 777     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 778         dmq1 = &local_dmq1;
 779         BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
 780     } else
 781         dmq1 = rsa->dmq1;
 782     if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx, rsa->_method_mod_q))
 783         goto err;
 784
 785     /* compute I mod p */
 786     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 787         c = &local_c;
 788         BN_with_flags(c, I, BN_FLG_CONSTTIME);
 789         if (!BN_mod(r1, c, rsa->p, ctx))
 790             goto err;
 791     } else {
 792         if (!BN_mod(r1, I, rsa->p, ctx))
 793             goto err;
 794     }
 795
 796     /* compute r1^dmp1 mod p */
 797     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 798         dmp1 = &local_dmp1;
 799         BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
 800     } else
 801         dmp1 = rsa->dmp1;
 802     if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx, rsa->_method_mod_p))
 803         goto err;
 804
 805     if (!BN_sub(r0, r0, m1))
 806         goto err;
 807     /*
 808      * This will help stop the size of r0 increasing, which does affect the
 809      * multiply if it optimised for a power of 2 size
 810      */
 811     if (BN_is_negative(r0))
 812         if (!BN_add(r0, r0, rsa->p))
 813             goto err;
 814
 815     if (!BN_mul(r1, r0, rsa->iqmp, ctx))
 816         goto err;
 817
 818     /* Turn BN_FLG_CONSTTIME flag on before division operation */
 819     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 820         pr1 = &local_r1;
 821         BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
 822     } else
 823         pr1 = r1;
 824     if (!BN_mod(r0, pr1, rsa->p, ctx))
 825         goto err;
 826
 827     /*
 828      * If p < q it is occasionally possible for the correction of adding 'p'
 829      * if r0 is negative above to leave the result still negative. This can
 830      * break the private key operations: the following second correction
 831      * should *always* correct this rare occurrence. This will *never* happen
 832      * with OpenSSL generated keys because they ensure p > q [steve]
 833      */
 834     if (BN_is_negative(r0))
 835         if (!BN_add(r0, r0, rsa->p))
 836             goto err;
 837     if (!BN_mul(r1, r0, rsa->q, ctx))
 838         goto err;
 839     if (!BN_add(r0, r1, m1))
 840         goto err;
 841
 842     if (rsa->e && rsa->n) {
 843         if (!rsa->
 844             meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx,
 845                              rsa->_method_mod_n))
 846             goto err;
 847         /*
 848          * If 'I' was greater than (or equal to) rsa->n, the operation will
 849          * be equivalent to using 'I mod n'. However, the result of the
 850          * verify will *always* be less than 'n' so we don't check for
 851          * absolute equality, just congruency.
 852          */
 853         if (!BN_sub(vrfy, vrfy, I))
 854             goto err;
 855         if (!BN_mod(vrfy, vrfy, rsa->n, ctx))
 856             goto err;
 857         if (BN_is_negative(vrfy))
 858             if (!BN_add(vrfy, vrfy, rsa->n))
 859                 goto err;
 860         if (!BN_is_zero(vrfy)) {
 861             /*
 862              * 'I' and 'vrfy' aren't congruent mod n. Don't leak
 863              * miscalculated CRT output, just do a raw (slower) mod_exp and
 864              * return that instead.
 865              */
 866
 867             BIGNUM local_d;
 868             BIGNUM *d = NULL;
 869
 870             if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 871                 d = &local_d;
 872                 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 873             } else
 874                 d = rsa->d;
 875             if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx,
 876                                        rsa->_method_mod_n))
 877                 goto err;
 878         }
 879     }
 880     ret = 1;
 881  err:
 882     BN_CTX_end(ctx);
 883     return (ret);
 884 }
 885
 886 static int RSA_eay_init(RSA *rsa)
 887 {
 888     rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE;
 889     return (1);
 890 }
 891
 892 static int RSA_eay_finish(RSA *rsa)
 893 {
 894     if (rsa->_method_mod_n != NULL)
 895         BN_MONT_CTX_free(rsa->_method_mod_n);
 896     if (rsa->_method_mod_p != NULL)
 897         BN_MONT_CTX_free(rsa->_method_mod_p);
 898     if (rsa->_method_mod_q != NULL)
 899         BN_MONT_CTX_free(rsa->_method_mod_q);
 900     return (1);
 901 }
 902
 903 #endif