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 = 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     BN_BLINDING_free(ret);
 170     return (NULL);
 171 }
 172
 173 void BN_BLINDING_free(BN_BLINDING *r)
 174 {
 175     if (r == NULL)
 176         return;
 177
 178     BN_free(r->A);
 179     BN_free(r->Ai);
 180     BN_free(r->e);
 181     BN_free(r->mod);
 182     OPENSSL_free(r);
 183 }
 184
 185 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
 186 {
 187     int ret = 0;
 188
 189     if ((b->A == NULL) || (b->Ai == NULL)) {
 190         BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED);
 191         goto err;
 192     }
 193
 194     if (b->counter == -1)
 195         b->counter = 0;
 196
 197     if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
 198         !(b->flags & BN_BLINDING_NO_RECREATE)) {
 199         /* re-create blinding parameters */
 200         if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
 201             goto err;
 202     } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
 203         if (!BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
 204             goto err;
 205         if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx))
 206             goto err;
 207     }
 208
 209     ret = 1;
 210  err:
 211     if (b->counter == BN_BLINDING_COUNTER)
 212         b->counter = 0;
 213     return (ret);
 214 }
 215
 216 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 217 {
 218     return BN_BLINDING_convert_ex(n, NULL, b, ctx);
 219 }
 220
 221 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
 222 {
 223     int ret = 1;
 224
 225     bn_check_top(n);
 226
 227     if ((b->A == NULL) || (b->Ai == NULL)) {
 228         BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED);
 229         return (0);
 230     }
 231
 232     if (b->counter == -1)
 233         /* Fresh blinding, doesn't need updating. */
 234         b->counter = 0;
 235     else if (!BN_BLINDING_update(b, ctx))
 236         return (0);
 237
 238     if (r != NULL) {
 239         if (!BN_copy(r, b->Ai))
 240             ret = 0;
 241     }
 242
 243     if (!BN_mod_mul(n, n, b->A, b->mod, ctx))
 244         ret = 0;
 245
 246     return ret;
 247 }
 248
 249 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 250 {
 251     return BN_BLINDING_invert_ex(n, NULL, b, ctx);
 252 }
 253
 254 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
 255                           BN_CTX *ctx)
 256 {
 257     int ret;
 258
 259     bn_check_top(n);
 260
 261     if (r != NULL)
 262         ret = BN_mod_mul(n, n, r, b->mod, ctx);
 263     else {
 264         if (b->Ai == NULL) {
 265             BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED);
 266             return (0);
 267         }
 268         ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
 269     }
 270
 271     bn_check_top(n);
 272     return (ret);
 273 }
 274
 275 #ifndef OPENSSL_NO_DEPRECATED
 276 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
 277 {
 278     return b->thread_id;
 279 }
 280
 281 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
 282 {
 283     b->thread_id = n;
 284 }
 285 #endif
 286
 287 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b)
 288 {
 289     return &b->tid;
 290 }
 291
 292 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
 293 {
 294     return b->flags;
 295 }
 296
 297 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
 298 {
 299     b->flags = flags;
 300 }
 301
 302 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
 303                                       const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
 304                                       int (*bn_mod_exp) (BIGNUM *r,
 305                                                          const BIGNUM *a,
 306                                                          const BIGNUM *p,
 307                                                          const BIGNUM *m,
 308                                                          BN_CTX *ctx,
 309                                                          BN_MONT_CTX *m_ctx),
 310                                       BN_MONT_CTX *m_ctx)
 311 {
 312     int retry_counter = 32;
 313     BN_BLINDING *ret = NULL;
 314
 315     if (b == NULL)
 316         ret = BN_BLINDING_new(NULL, NULL, m);
 317     else
 318         ret = b;
 319
 320     if (ret == NULL)
 321         goto err;
 322
 323     if (ret->A == NULL && (ret->A = BN_new()) == NULL)
 324         goto err;
 325     if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
 326         goto err;
 327
 328     if (e != NULL) {
 329         BN_free(ret->e);
 330         ret->e = BN_dup(e);
 331     }
 332     if (ret->e == NULL)
 333         goto err;
 334
 335     if (bn_mod_exp != NULL)
 336         ret->bn_mod_exp = bn_mod_exp;
 337     if (m_ctx != NULL)
 338         ret->m_ctx = m_ctx;
 339
 340     do {
 341         int rv;
 342         if (!BN_rand_range(ret->A, ret->mod))
 343             goto err;
 344         if (!int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv)) {
 345             /*
 346              * this should almost never happen for good RSA keys
 347              */
 348             if (rv) {
 349                 if (retry_counter-- == 0) {
 350                     BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
 351                           BN_R_TOO_MANY_ITERATIONS);
 352                     goto err;
 353                 }
 354             } else
 355                 goto err;
 356         } else
 357             break;
 358     } while (1);
 359
 360     if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
 361         if (!ret->bn_mod_exp
 362             (ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
 363             goto err;
 364     } else {
 365         if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
 366             goto err;
 367     }
 368
 369     return ret;
 370  err:
 371     if (b == NULL) {
 372         BN_BLINDING_free(ret);
 373         ret = NULL;
 374     }
 375
 376     return ret;
 377 }