crypto/bn/bn_blind.c

   1 /* crypto/bn/bn_blind.c */
   2 /* ====================================================================
   3  * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the OpenSSL Project
  20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  21  *
  22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission. For written permission, please contact
  25  *    openssl-core@openssl.org.
  26  *
  27  * 5. Products derived from this software may not be called "OpenSSL"
  28  *    nor may "OpenSSL" appear in their names without prior written
  29  *    permission of the OpenSSL Project.
  30  *
  31  * 6. Redistributions of any form whatsoever must retain the following
  32  *    acknowledgment:
  33  *    "This product includes software developed by the OpenSSL Project
  34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  47  * OF THE POSSIBILITY OF SUCH DAMAGE.
  48  * ====================================================================
  49  *
  50  * This product includes cryptographic software written by Eric Young
  51  * (eay@cryptsoft.com).  This product includes software written by Tim
  52  * Hudson (tjh@cryptsoft.com).
  53  *
  54  */
  55 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  56  * All rights reserved.
  57  *
  58  * This package is an SSL implementation written
  59  * by Eric Young (eay@cryptsoft.com).
  60  * The implementation was written so as to conform with Netscapes SSL.
  61  *
  62  * This library is free for commercial and non-commercial use as long as
  63  * the following conditions are aheared to.  The following conditions
  64  * apply to all code found in this distribution, be it the RC4, RSA,
  65  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  66  * included with this distribution is covered by the same copyright terms
  67  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  68  *
  69  * Copyright remains Eric Young's, and as such any Copyright notices in
  70  * the code are not to be removed.
  71  * If this package is used in a product, Eric Young should be given attribution
  72  * as the author of the parts of the library used.
  73  * This can be in the form of a textual message at program startup or
  74  * in documentation (online or textual) provided with the package.
  75  *
  76  * Redistribution and use in source and binary forms, with or without
  77  * modification, are permitted provided that the following conditions
  78  * are met:
  79  * 1. Redistributions of source code must retain the copyright
  80  *    notice, this list of conditions and the following disclaimer.
  81  * 2. Redistributions in binary form must reproduce the above copyright
  82  *    notice, this list of conditions and the following disclaimer in the
  83  *    documentation and/or other materials provided with the distribution.
  84  * 3. All advertising materials mentioning features or use of this software
  85  *    must display the following acknowledgement:
  86  *    "This product includes cryptographic software written by
  87  *     Eric Young (eay@cryptsoft.com)"
  88  *    The word 'cryptographic' can be left out if the rouines from the library
  89  *    being used are not cryptographic related :-).
  90  * 4. If you include any Windows specific code (or a derivative thereof) from
  91  *    the apps directory (application code) you must include an acknowledgement:
  92  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  93  *
  94  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  95  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  96  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  97  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  98  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  99  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 100  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 101  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 102  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 103  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 104  * SUCH DAMAGE.
 105  *
 106  * The licence and distribution terms for any publically available version or
 107  * derivative of this code cannot be changed.  i.e. this code cannot simply be
 108  * copied and put under another distribution licence
 109  * [including the GNU Public Licence.]
 110  */
 111
 112 #include "cryptlib.h"
 113 #include "bn_lcl.h"
 114
 115 #define BN_BLINDING_COUNTER     32
 116
 117 struct bn_blinding_st {
 118     BIGNUM *A;
 119     BIGNUM *Ai;
 120     BIGNUM *e;
 121     BIGNUM *mod;                /* just a reference */
 122 #ifndef OPENSSL_NO_DEPRECATED
 123     unsigned long thread_id;    /* added in OpenSSL 0.9.6j and 0.9.7b; used
 124                                  * only by crypto/rsa/rsa_eay.c, rsa_lib.c */
 125 #endif
 126     CRYPTO_THREADID tid;
 127     int counter;
 128     unsigned long flags;
 129     BN_MONT_CTX *m_ctx;
 130     int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
 131                        const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
 132 };
 133
 134 BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
 135 {
 136     BN_BLINDING *ret = NULL;
 137
 138     bn_check_top(mod);
 139
 140     if ((ret = (BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL) {
 141         BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
 142         return (NULL);
 143     }
 144     memset(ret, 0, sizeof(BN_BLINDING));
 145     if (A != NULL) {
 146         if ((ret->A = BN_dup(A)) == NULL)
 147             goto err;
 148     }
 149     if (Ai != NULL) {
 150         if ((ret->Ai = BN_dup(Ai)) == NULL)
 151             goto err;
 152     }
 153
 154     /* save a copy of mod in the BN_BLINDING structure */
 155     if ((ret->mod = BN_dup(mod)) == NULL)
 156         goto err;
 157     if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
 158         BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
 159
 160     /*
 161      * Set the counter to the special value -1 to indicate that this is
 162      * never-used fresh blinding that does not need updating before first
 163      * use.
 164      */
 165     ret->counter = -1;
 166     CRYPTO_THREADID_current(&ret->tid);
 167     return (ret);
 168  err:
 169     if (ret != NULL)
 170         BN_BLINDING_free(ret);
 171     return (NULL);
 172 }
 173
 174 void BN_BLINDING_free(BN_BLINDING *r)
 175 {
 176     if (r == NULL)
 177         return;
 178
 179     if (r->A != NULL)
 180         BN_free(r->A);
 181     if (r->Ai != NULL)
 182         BN_free(r->Ai);
 183     if (r->e != NULL)
 184         BN_free(r->e);
 185     if (r->mod != NULL)
 186         BN_free(r->mod);
 187     OPENSSL_free(r);
 188 }
 189
 190 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
 191 {
 192     int ret = 0;
 193
 194     if ((b->A == NULL) || (b->Ai == NULL)) {
 195         BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED);
 196         goto err;
 197     }
 198
 199     if (b->counter == -1)
 200         b->counter = 0;
 201
 202     if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
 203         !(b->flags & BN_BLINDING_NO_RECREATE)) {
 204         /* re-create blinding parameters */
 205         if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
 206             goto err;
 207     } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
 208         if (!BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
 209             goto err;
 210         if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx))
 211             goto err;
 212     }
 213
 214     ret = 1;
 215  err:
 216     if (b->counter == BN_BLINDING_COUNTER)
 217         b->counter = 0;
 218     return (ret);
 219 }
 220
 221 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 222 {
 223     return BN_BLINDING_convert_ex(n, NULL, b, ctx);
 224 }
 225
 226 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
 227 {
 228     int ret = 1;
 229
 230     bn_check_top(n);
 231
 232     if ((b->A == NULL) || (b->Ai == NULL)) {
 233         BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED);
 234         return (0);
 235     }
 236
 237     if (b->counter == -1)
 238         /* Fresh blinding, doesn't need updating. */
 239         b->counter = 0;
 240     else if (!BN_BLINDING_update(b, ctx))
 241         return (0);
 242
 243     if (r != NULL) {
 244         if (!BN_copy(r, b->Ai))
 245             ret = 0;
 246     }
 247
 248     if (!BN_mod_mul(n, n, b->A, b->mod, ctx))
 249         ret = 0;
 250
 251     return ret;
 252 }
 253
 254 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 255 {
 256     return BN_BLINDING_invert_ex(n, NULL, b, ctx);
 257 }
 258
 259 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
 260                           BN_CTX *ctx)
 261 {
 262     int ret;
 263
 264     bn_check_top(n);
 265
 266     if (r != NULL)
 267         ret = BN_mod_mul(n, n, r, b->mod, ctx);
 268     else {
 269         if (b->Ai == NULL) {
 270             BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED);
 271             return (0);
 272         }
 273         ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
 274     }
 275
 276     bn_check_top(n);
 277     return (ret);
 278 }
 279
 280 #ifndef OPENSSL_NO_DEPRECATED
 281 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
 282 {
 283     return b->thread_id;
 284 }
 285
 286 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
 287 {
 288     b->thread_id = n;
 289 }
 290 #endif
 291
 292 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b)
 293 {
 294     return &b->tid;
 295 }
 296
 297 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
 298 {
 299     return b->flags;
 300 }
 301
 302 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
 303 {
 304     b->flags = flags;
 305 }
 306
 307 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
 308                                       const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
 309                                       int (*bn_mod_exp) (BIGNUM *r,
 310                                                          const BIGNUM *a,
 311                                                          const BIGNUM *p,
 312                                                          const BIGNUM *m,
 313                                                          BN_CTX *ctx,
 314                                                          BN_MONT_CTX *m_ctx),
 315                                       BN_MONT_CTX *m_ctx)
 316 {
 317     int retry_counter = 32;
 318     BN_BLINDING *ret = NULL;
 319
 320     if (b == NULL)
 321         ret = BN_BLINDING_new(NULL, NULL, m);
 322     else
 323         ret = b;
 324
 325     if (ret == NULL)
 326         goto err;
 327
 328     if (ret->A == NULL && (ret->A = BN_new()) == NULL)
 329         goto err;
 330     if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
 331         goto err;
 332
 333     if (e != NULL) {
 334         if (ret->e != NULL)
 335             BN_free(ret->e);
 336         ret->e = BN_dup(e);
 337     }
 338     if (ret->e == NULL)
 339         goto err;
 340
 341     if (bn_mod_exp != NULL)
 342         ret->bn_mod_exp = bn_mod_exp;
 343     if (m_ctx != NULL)
 344         ret->m_ctx = m_ctx;
 345
 346     do {
 347         int rv;
 348         if (!BN_rand_range(ret->A, ret->mod))
 349             goto err;
 350         if (!int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv)) {
 351             /*
 352              * this should almost never happen for good RSA keys
 353              */
 354             if (rv) {
 355                 if (retry_counter-- == 0) {
 356                     BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
 357                           BN_R_TOO_MANY_ITERATIONS);
 358                     goto err;
 359                 }
 360             } else
 361                 goto err;
 362         } else
 363             break;
 364     } while (1);
 365
 366     if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
 367         if (!ret->bn_mod_exp
 368             (ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
 369             goto err;
 370     } else {
 371         if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
 372             goto err;
 373     }
 374
 375     return ret;
 376  err:
 377     if (b == NULL && ret != NULL) {
 378         BN_BLINDING_free(ret);
 379         ret = NULL;
 380     }
 381
 382     return ret;
 383 }