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 "internal/cryptlib.h"
 113 #include "internal/bn_int.h"
 114 #include <openssl/rsa.h>
 115 #include <openssl/rand.h>
 116
 117 #ifndef RSA_NULL
 118
 119 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 120                                   unsigned char *to, RSA *rsa, int padding);
 121 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 122                                    unsigned char *to, RSA *rsa, int padding);
 123 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 124                                   unsigned char *to, RSA *rsa, int padding);
 125 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 126                                    unsigned char *to, RSA *rsa, int padding);
 127 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa,
 128                            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
 139                                  * if e == 3 */
 140     RSA_eay_init,
 141     RSA_eay_finish,
 142     RSA_FLAG_FIPS_METHOD,       /* flags */
 143     NULL,
 144     0,                          /* rsa_sign */
 145     0,                          /* rsa_verify */
 146     NULL                        /* rsa_keygen */
 147 };
 148
 149 const RSA_METHOD *RSA_PKCS1_OpenSSL(void)
 150 {
 151     return (&rsa_pkcs1_eay_meth);
 152 }
 153
 154 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 155                                   unsigned char *to, RSA *rsa, int padding)
 156 {
 157     BIGNUM *f, *ret;
 158     int i, j, k, num = 0, r = -1;
 159     unsigned char *buf = NULL;
 160     BN_CTX *ctx = NULL;
 161
 162     if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
 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         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 169         return -1;
 170     }
 171
 172     /* for large moduli, enforce exponent limit */
 173     if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) {
 174         if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
 175             RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
 176             return -1;
 177         }
 178     }
 179
 180     if ((ctx = BN_CTX_new()) == NULL)
 181         goto err;
 182     BN_CTX_start(ctx);
 183     f = BN_CTX_get(ctx);
 184     ret = BN_CTX_get(ctx);
 185     num = BN_num_bytes(rsa->n);
 186     buf = OPENSSL_malloc(num);
 187     if (f == NULL || ret == NULL || buf == NULL) {
 188         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE);
 189         goto err;
 190     }
 191
 192     switch (padding) {
 193     case RSA_PKCS1_PADDING:
 194         i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen);
 195         break;
 196     case RSA_PKCS1_OAEP_PADDING:
 197         i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0);
 198         break;
 199     case RSA_SSLV23_PADDING:
 200         i = RSA_padding_add_SSLv23(buf, num, from, flen);
 201         break;
 202     case RSA_NO_PADDING:
 203         i = RSA_padding_add_none(buf, num, from, flen);
 204         break;
 205     default:
 206         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 207         goto err;
 208     }
 209     if (i <= 0)
 210         goto err;
 211
 212     if (BN_bin2bn(buf, num, f) == NULL)
 213         goto err;
 214
 215     if (BN_ucmp(f, rsa->n) >= 0) {
 216         /* usually the padding functions would catch this */
 217         RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,
 218                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 219         goto err;
 220     }
 221
 222     if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 223         if (!BN_MONT_CTX_set_locked
 224             (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 225             goto err;
 226
 227     if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx,
 228                                rsa->_method_mod_n))
 229         goto err;
 230
 231     /*
 232      * put in leading 0 bytes if the number is less than the length of the
 233      * modulus
 234      */
 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         BN_CTX_end(ctx);
 244     BN_CTX_free(ctx);
 245     OPENSSL_clear_free(buf, num);
 246     return (r);
 247 }
 248
 249 static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
 250 {
 251     BN_BLINDING *ret;
 252     int got_write_lock = 0;
 253     CRYPTO_THREADID cur;
 254
 255     CRYPTO_r_lock(CRYPTO_LOCK_RSA);
 256
 257     if (rsa->blinding == NULL) {
 258         CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 259         CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 260         got_write_lock = 1;
 261
 262         if (rsa->blinding == NULL)
 263             rsa->blinding = RSA_setup_blinding(rsa, ctx);
 264     }
 265
 266     ret = rsa->blinding;
 267     if (ret == NULL)
 268         goto err;
 269
 270     CRYPTO_THREADID_current(&cur);
 271     if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) {
 272         /* rsa->blinding is ours! */
 273
 274         *local = 1;
 275     } else {
 276         /* resort to rsa->mt_blinding instead */
 277
 278         /*
 279          * instructs rsa_blinding_convert(), rsa_blinding_invert() that the
 280          * BN_BLINDING is shared, meaning that accesses require locks, and
 281          * that the blinding factor must be stored outside the BN_BLINDING
 282          */
 283         *local = 0;
 284
 285         if (rsa->mt_blinding == NULL) {
 286             if (!got_write_lock) {
 287                 CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 288                 CRYPTO_w_lock(CRYPTO_LOCK_RSA);
 289                 got_write_lock = 1;
 290             }
 291
 292             if (rsa->mt_blinding == NULL)
 293                 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
 294         }
 295         ret = rsa->mt_blinding;
 296     }
 297
 298  err:
 299     if (got_write_lock)
 300         CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
 301     else
 302         CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
 303     return ret;
 304 }
 305
 306 static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
 307                                 BN_CTX *ctx)
 308 {
 309     if (unblind == NULL)
 310         /*
 311          * Local blinding: store the unblinding factor in BN_BLINDING.
 312          */
 313         return BN_BLINDING_convert_ex(f, NULL, b, ctx);
 314     else {
 315         /*
 316          * Shared blinding: store the unblinding factor outside BN_BLINDING.
 317          */
 318         int ret;
 319         CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
 320         ret = BN_BLINDING_convert_ex(f, unblind, b, ctx);
 321         CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
 322         return ret;
 323     }
 324 }
 325
 326 static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
 327                                BN_CTX *ctx)
 328 {
 329     /*
 330      * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex
 331      * will use the unblinding factor stored in BN_BLINDING. If BN_BLINDING
 332      * is shared between threads, unblind must be non-null:
 333      * BN_BLINDING_invert_ex will then use the local unblinding factor, and
 334      * will only read the modulus from BN_BLINDING. In both cases it's safe
 335      * to access the blinding without a lock.
 336      */
 337     return BN_BLINDING_invert_ex(f, unblind, b, ctx);
 338 }
 339
 340 /* signing */
 341 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 342                                    unsigned char *to, RSA *rsa, int padding)
 343 {
 344     BIGNUM *f, *ret, *res;
 345     int i, j, k, num = 0, r = -1;
 346     unsigned char *buf = NULL;
 347     BN_CTX *ctx = NULL;
 348     int local_blinding = 0;
 349     /*
 350      * Used only if the blinding structure is shared. A non-NULL unblind
 351      * instructs rsa_blinding_convert() and rsa_blinding_invert() to store
 352      * the unblinding factor outside the blinding structure.
 353      */
 354     BIGNUM *unblind = NULL;
 355     BN_BLINDING *blinding = NULL;
 356
 357     if ((ctx = BN_CTX_new()) == NULL)
 358         goto err;
 359     BN_CTX_start(ctx);
 360     f = BN_CTX_get(ctx);
 361     ret = BN_CTX_get(ctx);
 362     num = BN_num_bytes(rsa->n);
 363     buf = OPENSSL_malloc(num);
 364     if (f == NULL || ret == NULL || buf == NULL) {
 365         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
 366         goto err;
 367     }
 368
 369     switch (padding) {
 370     case RSA_PKCS1_PADDING:
 371         i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen);
 372         break;
 373     case RSA_X931_PADDING:
 374         i = RSA_padding_add_X931(buf, num, from, flen);
 375         break;
 376     case RSA_NO_PADDING:
 377         i = RSA_padding_add_none(buf, num, from, flen);
 378         break;
 379     case RSA_SSLV23_PADDING:
 380     default:
 381         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 382         goto err;
 383     }
 384     if (i <= 0)
 385         goto err;
 386
 387     if (BN_bin2bn(buf, num, f) == NULL)
 388         goto err;
 389
 390     if (BN_ucmp(f, rsa->n) >= 0) {
 391         /* usually the padding functions would catch this */
 392         RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,
 393                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 394         goto err;
 395     }
 396
 397     if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
 398         blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 399         if (blinding == NULL) {
 400             RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
 401             goto err;
 402         }
 403     }
 404
 405     if (blinding != NULL) {
 406         if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
 407             RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
 408             goto err;
 409         }
 410         if (!rsa_blinding_convert(blinding, f, unblind, ctx))
 411             goto err;
 412     }
 413
 414     if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
 415         ((rsa->p != NULL) &&
 416          (rsa->q != NULL) &&
 417          (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
 418         if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
 419             goto err;
 420     } else {
 421         BIGNUM *d = NULL, *local_d = NULL;
 422
 423         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 424             local_d = d = BN_new();
 425             if (d == NULL) {
 426                 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
 427                 goto err;
 428             }
 429             BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 430         } else
 431             d = rsa->d;
 432
 433         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 434             if (!BN_MONT_CTX_set_locked
 435                 (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx)) {
 436                 BN_free(local_d);
 437                 goto err;
 438             }
 439
 440         if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
 441                                    rsa->_method_mod_n)) {
 442             BN_free(local_d);
 443             goto err;
 444         }
 445         BN_free(local_d);
 446     }
 447
 448     if (blinding)
 449         if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
 450             goto err;
 451
 452     if (padding == RSA_X931_PADDING) {
 453         BN_sub(f, rsa->n, ret);
 454         if (BN_cmp(ret, f) > 0)
 455             res = f;
 456         else
 457             res = ret;
 458     } else
 459         res = ret;
 460
 461     /*
 462      * put in leading 0 bytes if the number is less than the length of the
 463      * modulus
 464      */
 465     j = BN_num_bytes(res);
 466     i = BN_bn2bin(res, &(to[num - j]));
 467     for (k = 0; k < (num - i); k++)
 468         to[k] = 0;
 469
 470     r = num;
 471  err:
 472     if (ctx != NULL)
 473         BN_CTX_end(ctx);
 474     BN_CTX_free(ctx);
 475     OPENSSL_clear_free(buf, num);
 476     return (r);
 477 }
 478
 479 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 480                                    unsigned char *to, RSA *rsa, int padding)
 481 {
 482     BIGNUM *f, *ret;
 483     int j, num = 0, r = -1;
 484     unsigned char *p;
 485     unsigned char *buf = NULL;
 486     BN_CTX *ctx = NULL;
 487     int local_blinding = 0;
 488     /*
 489      * Used only if the blinding structure is shared. A non-NULL unblind
 490      * instructs rsa_blinding_convert() and rsa_blinding_invert() to store
 491      * the unblinding factor outside the blinding structure.
 492      */
 493     BIGNUM *unblind = NULL;
 494     BN_BLINDING *blinding = NULL;
 495
 496     if ((ctx = BN_CTX_new()) == NULL)
 497         goto err;
 498     BN_CTX_start(ctx);
 499     f = BN_CTX_get(ctx);
 500     ret = BN_CTX_get(ctx);
 501     num = BN_num_bytes(rsa->n);
 502     buf = OPENSSL_malloc(num);
 503     if (f == NULL || ret == NULL || buf == NULL) {
 504         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
 505         goto err;
 506     }
 507
 508     /*
 509      * This check was for equality but PGP does evil things and chops off the
 510      * top '0' bytes
 511      */
 512     if (flen > num) {
 513         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,
 514                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)
 520         goto err;
 521
 522     if (BN_ucmp(f, rsa->n) >= 0) {
 523         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,
 524                RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 525         goto err;
 526     }
 527
 528     if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
 529         blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
 530         if (blinding == NULL) {
 531             RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
 532             goto err;
 533         }
 534     }
 535
 536     if (blinding != NULL) {
 537         if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
 538             RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
 539             goto err;
 540         }
 541         if (!rsa_blinding_convert(blinding, f, unblind, ctx))
 542             goto err;
 543     }
 544
 545     /* do the decrypt */
 546     if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
 547         ((rsa->p != NULL) &&
 548          (rsa->q != NULL) &&
 549          (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
 550         if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
 551             goto err;
 552     } else {
 553         BIGNUM *d = NULL, *local_d = NULL;
 554
 555         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 556             local_d = d = BN_new();
 557             if (d == NULL) {
 558                 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
 559                 goto err;
 560             }
 561             BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 562         } else
 563             d = rsa->d;
 564
 565         if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 566             if (!BN_MONT_CTX_set_locked
 567                 (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx)) {
 568                 BN_free(local_d);
 569                 goto err;
 570             }
 571         if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
 572                                    rsa->_method_mod_n)) {
 573             BN_free(local_d);
 574             goto err;
 575         }
 576         BN_free(local_d);
 577     }
 578
 579     if (blinding)
 580         if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
 581             goto err;
 582
 583     p = buf;
 584     j = BN_bn2bin(ret, p);      /* j is only used with no-padding mode */
 585
 586     switch (padding) {
 587     case RSA_PKCS1_PADDING:
 588         r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num);
 589         break;
 590     case RSA_PKCS1_OAEP_PADDING:
 591         r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0);
 592         break;
 593     case RSA_SSLV23_PADDING:
 594         r = RSA_padding_check_SSLv23(to, num, buf, j, num);
 595         break;
 596     case RSA_NO_PADDING:
 597         r = RSA_padding_check_none(to, num, buf, j, num);
 598         break;
 599     default:
 600         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
 601         goto err;
 602     }
 603     if (r < 0)
 604         RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
 605
 606  err:
 607     if (ctx != NULL)
 608         BN_CTX_end(ctx);
 609     BN_CTX_free(ctx);
 610     OPENSSL_clear_free(buf, num);
 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 == NULL || ret == NULL || buf == NULL) {
 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) && ((bn_get_words(ret)[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     OPENSSL_clear_free(buf, num);
 710     return (r);
 711 }
 712
 713 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 714 {
 715     BIGNUM *r1, *m1, *vrfy;
 716     BIGNUM *local_dmp1, *local_dmq1, *local_c, *local_r1;
 717     BIGNUM *dmp1, *dmq1, *c, *pr1;
 718     int ret = 0;
 719
 720     BN_CTX_start(ctx);
 721
 722     local_dmp1 = BN_new();
 723     local_dmq1 = BN_new();
 724     local_c = BN_new();
 725     local_r1 = BN_new();
 726     if (local_dmp1 == NULL
 727             || local_dmq1 == NULL || local_c == NULL || local_r1 == NULL)
 728         goto err;
 729
 730     r1 = BN_CTX_get(ctx);
 731     m1 = BN_CTX_get(ctx);
 732     vrfy = BN_CTX_get(ctx);
 733
 734     {
 735         BIGNUM *local_p = NULL, *local_q = NULL;
 736         BIGNUM *p = NULL, *q = NULL;
 737
 738         /*
 739          * Make sure BN_mod_inverse in Montgomery intialization uses the
 740          * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
 741          */
 742         if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 743             local_p = p = BN_new();
 744             if (p == NULL)
 745                 goto err;
 746             BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
 747
 748             local_q = q = BN_new();
 749             if (q == NULL) {
 750                 BN_free(local_p);
 751                 goto err;
 752             }
 753             BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
 754         } else {
 755             p = rsa->p;
 756             q = rsa->q;
 757         }
 758
 759         if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
 760             if (!BN_MONT_CTX_set_locked
 761                 (&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx)
 762                 || !BN_MONT_CTX_set_locked(&rsa->_method_mod_q,
 763                                            CRYPTO_LOCK_RSA, q, ctx)) {
 764                 BN_free(local_p);
 765                 BN_free(local_q);
 766                 goto err;
 767             }
 768         }
 769         BN_free(local_p);
 770         BN_free(local_q);
 771     }
 772
 773     if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 774         if (!BN_MONT_CTX_set_locked
 775             (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
 776             goto err;
 777
 778     /* compute I mod q */
 779     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 780         c = local_c;
 781         BN_with_flags(c, I, BN_FLG_CONSTTIME);
 782         if (!BN_mod(r1, c, rsa->q, ctx))
 783             goto err;
 784     } else {
 785         if (!BN_mod(r1, I, rsa->q, ctx))
 786             goto err;
 787     }
 788
 789     /* compute r1^dmq1 mod q */
 790     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 791         dmq1 = local_dmq1;
 792         BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
 793     } else
 794         dmq1 = rsa->dmq1;
 795     if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx, rsa->_method_mod_q))
 796         goto err;
 797
 798     /* compute I mod p */
 799     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 800         c = local_c;
 801         BN_with_flags(c, I, BN_FLG_CONSTTIME);
 802         if (!BN_mod(r1, c, rsa->p, ctx))
 803             goto err;
 804     } else {
 805         if (!BN_mod(r1, I, rsa->p, ctx))
 806             goto err;
 807     }
 808
 809     /* compute r1^dmp1 mod p */
 810     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 811         dmp1 = local_dmp1;
 812         BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
 813     } else
 814         dmp1 = rsa->dmp1;
 815     if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx, rsa->_method_mod_p))
 816         goto err;
 817
 818     if (!BN_sub(r0, r0, m1))
 819         goto err;
 820     /*
 821      * This will help stop the size of r0 increasing, which does affect the
 822      * multiply if it optimised for a power of 2 size
 823      */
 824     if (BN_is_negative(r0))
 825         if (!BN_add(r0, r0, rsa->p))
 826             goto err;
 827
 828     if (!BN_mul(r1, r0, rsa->iqmp, ctx))
 829         goto err;
 830
 831     /* Turn BN_FLG_CONSTTIME flag on before division operation */
 832     if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 833         pr1 = local_r1;
 834         BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
 835     } else
 836         pr1 = r1;
 837     if (!BN_mod(r0, pr1, rsa->p, ctx))
 838         goto err;
 839
 840     /*
 841      * If p < q it is occasionally possible for the correction of adding 'p'
 842      * if r0 is negative above to leave the result still negative. This can
 843      * break the private key operations: the following second correction
 844      * should *always* correct this rare occurrence. This will *never* happen
 845      * with OpenSSL generated keys because they ensure p > q [steve]
 846      */
 847     if (BN_is_negative(r0))
 848         if (!BN_add(r0, r0, rsa->p))
 849             goto err;
 850     if (!BN_mul(r1, r0, rsa->q, ctx))
 851         goto err;
 852     if (!BN_add(r0, r1, m1))
 853         goto err;
 854
 855     if (rsa->e && rsa->n) {
 856         if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx,
 857                                    rsa->_method_mod_n))
 858             goto err;
 859         /*
 860          * If 'I' was greater than (or equal to) rsa->n, the operation will
 861          * be equivalent to using 'I mod n'. However, the result of the
 862          * verify will *always* be less than 'n' so we don't check for
 863          * absolute equality, just congruency.
 864          */
 865         if (!BN_sub(vrfy, vrfy, I))
 866             goto err;
 867         if (!BN_mod(vrfy, vrfy, rsa->n, ctx))
 868             goto err;
 869         if (BN_is_negative(vrfy))
 870             if (!BN_add(vrfy, vrfy, rsa->n))
 871                 goto err;
 872         if (!BN_is_zero(vrfy)) {
 873             /*
 874              * 'I' and 'vrfy' aren't congruent mod n. Don't leak
 875              * miscalculated CRT output, just do a raw (slower) mod_exp and
 876              * return that instead.
 877              */
 878
 879             BIGNUM *local_d = NULL;
 880             BIGNUM *d = NULL;
 881
 882             if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
 883                 local_d = d = BN_new();
 884                 if (d == NULL)
 885                     goto err;
 886                 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
 887             } else
 888                 d = rsa->d;
 889             if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx,
 890                                        rsa->_method_mod_n)) {
 891                 BN_free(local_d);
 892                 goto err;
 893             }
 894
 895             BN_free(local_d);
 896         }
 897     }
 898     ret = 1;
 899  err:
 900     BN_free(local_dmp1);
 901     BN_free(local_dmq1);
 902     BN_free(local_c);
 903     BN_free(local_r1);
 904     BN_CTX_end(ctx);
 905     return (ret);
 906 }
 907
 908 static int RSA_eay_init(RSA *rsa)
 909 {
 910     rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE;
 911     return (1);
 912 }
 913
 914 static int RSA_eay_finish(RSA *rsa)
 915 {
 916     BN_MONT_CTX_free(rsa->_method_mod_n);
 917     BN_MONT_CTX_free(rsa->_method_mod_p);
 918     BN_MONT_CTX_free(rsa->_method_mod_q);
 919     return (1);
 920 }
 921
 922 #endif