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 "internal/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 = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
 141         BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
 142         return (NULL);
 143     }
 144     if (A != NULL) {
 145         if ((ret->A = BN_dup(A)) == NULL)
 146             goto err;
 147     }
 148     if (Ai != NULL) {
 149         if ((ret->Ai = BN_dup(Ai)) == NULL)
 150             goto err;
 151     }
 152
 153     /* save a copy of mod in the BN_BLINDING structure */
 154     if ((ret->mod = BN_dup(mod)) == NULL)
 155         goto err;
 156     if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
 157         BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
 158
 159     /*
 160      * Set the counter to the special value -1 to indicate that this is
 161      * never-used fresh blinding that does not need updating before first
 162      * use.
 163      */
 164     ret->counter = -1;
 165     CRYPTO_THREADID_current(&ret->tid);
 166     return (ret);
 167  err:
 168     BN_BLINDING_free(ret);
 169     return (NULL);
 170 }
 171
 172 void BN_BLINDING_free(BN_BLINDING *r)
 173 {
 174     if (r == NULL)
 175         return;
 176
 177     BN_free(r->A);
 178     BN_free(r->Ai);
 179     BN_free(r->e);
 180     BN_free(r->mod);
 181     OPENSSL_free(r);
 182 }
 183
 184 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
 185 {
 186     int ret = 0;
 187
 188     if ((b->A == NULL) || (b->Ai == NULL)) {
 189         BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED);
 190         goto err;
 191     }
 192
 193     if (b->counter == -1)
 194         b->counter = 0;
 195
 196     if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
 197         !(b->flags & BN_BLINDING_NO_RECREATE)) {
 198         /* re-create blinding parameters */
 199         if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
 200             goto err;
 201     } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
 202         if (!BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
 203             goto err;
 204         if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx))
 205             goto err;
 206     }
 207
 208     ret = 1;
 209  err:
 210     if (b->counter == BN_BLINDING_COUNTER)
 211         b->counter = 0;
 212     return (ret);
 213 }
 214
 215 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 216 {
 217     return BN_BLINDING_convert_ex(n, NULL, b, ctx);
 218 }
 219
 220 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
 221 {
 222     int ret = 1;
 223
 224     bn_check_top(n);
 225
 226     if ((b->A == NULL) || (b->Ai == NULL)) {
 227         BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED);
 228         return (0);
 229     }
 230
 231     if (b->counter == -1)
 232         /* Fresh blinding, doesn't need updating. */
 233         b->counter = 0;
 234     else if (!BN_BLINDING_update(b, ctx))
 235         return (0);
 236
 237     if (r != NULL) {
 238         if (!BN_copy(r, b->Ai))
 239             ret = 0;
 240     }
 241
 242     if (!BN_mod_mul(n, n, b->A, b->mod, ctx))
 243         ret = 0;
 244
 245     return ret;
 246 }
 247
 248 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 249 {
 250     return BN_BLINDING_invert_ex(n, NULL, b, ctx);
 251 }
 252
 253 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
 254                           BN_CTX *ctx)
 255 {
 256     int ret;
 257
 258     bn_check_top(n);
 259
 260     if (r != NULL)
 261         ret = BN_mod_mul(n, n, r, b->mod, ctx);
 262     else {
 263         if (b->Ai == NULL) {
 264             BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED);
 265             return (0);
 266         }
 267         ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
 268     }
 269
 270     bn_check_top(n);
 271     return (ret);
 272 }
 273
 274 #ifndef OPENSSL_NO_DEPRECATED
 275 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
 276 {
 277     return b->thread_id;
 278 }
 279
 280 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
 281 {
 282     b->thread_id = n;
 283 }
 284 #endif
 285
 286 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b)
 287 {
 288     return &b->tid;
 289 }
 290
 291 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
 292 {
 293     return b->flags;
 294 }
 295
 296 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
 297 {
 298     b->flags = flags;
 299 }
 300
 301 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
 302                                       const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
 303                                       int (*bn_mod_exp) (BIGNUM *r,
 304                                                          const BIGNUM *a,
 305                                                          const BIGNUM *p,
 306                                                          const BIGNUM *m,
 307                                                          BN_CTX *ctx,
 308                                                          BN_MONT_CTX *m_ctx),
 309                                       BN_MONT_CTX *m_ctx)
 310 {
 311     int retry_counter = 32;
 312     BN_BLINDING *ret = NULL;
 313
 314     if (b == NULL)
 315         ret = BN_BLINDING_new(NULL, NULL, m);
 316     else
 317         ret = b;
 318
 319     if (ret == NULL)
 320         goto err;
 321
 322     if (ret->A == NULL && (ret->A = BN_new()) == NULL)
 323         goto err;
 324     if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
 325         goto err;
 326
 327     if (e != NULL) {
 328         BN_free(ret->e);
 329         ret->e = BN_dup(e);
 330     }
 331     if (ret->e == NULL)
 332         goto err;
 333
 334     if (bn_mod_exp != NULL)
 335         ret->bn_mod_exp = bn_mod_exp;
 336     if (m_ctx != NULL)
 337         ret->m_ctx = m_ctx;
 338
 339     do {
 340         int rv;
 341         if (!BN_rand_range(ret->A, ret->mod))
 342             goto err;
 343         if (!int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv)) {
 344             /*
 345              * this should almost never happen for good RSA keys
 346              */
 347             if (rv) {
 348                 if (retry_counter-- == 0) {
 349                     BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
 350                           BN_R_TOO_MANY_ITERATIONS);
 351                     goto err;
 352                 }
 353             } else
 354                 goto err;
 355         } else
 356             break;
 357     } while (1);
 358
 359     if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
 360         if (!ret->bn_mod_exp
 361             (ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
 362             goto err;
 363     } else {
 364         if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
 365             goto err;
 366     }
 367
 368     return ret;
 369  err:
 370     if (b == NULL) {
 371         BN_BLINDING_free(ret);
 372         ret = NULL;
 373     }
 374
 375     return ret;
 376 }