crypto/bn/bn_blind.c

   1 /* crypto/bn/bn_blind.c */
   2 /* ====================================================================
   3  * Copyright (c) 1998-2005 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 <stdio.h>
 113 #include "cryptlib.h"
 114 #include "bn_lcl.h"
 115
 116 #define BN_BLINDING_COUNTER     32
 117
 118 struct bn_blinding_st
 119         {
 120         BIGNUM *A;
 121         BIGNUM *Ai;
 122         BIGNUM *e;
 123         BIGNUM *mod; /* just a reference */
 124         unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b;
 125                                   * used only by crypto/rsa/rsa_eay.c, rsa_lib.c */
 126         unsigned int  counter;
 127         unsigned long flags;
 128         BN_MONT_CTX *m_ctx;
 129         int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
 130                           const BIGNUM *m, BN_CTX *ctx,
 131                           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                 {
 142                 BNerr(BN_F_BN_BLINDING_NEW,ERR_R_MALLOC_FAILURE);
 143                 return(NULL);
 144                 }
 145         memset(ret,0,sizeof(BN_BLINDING));
 146         if (A != NULL)
 147                 {
 148                 if ((ret->A  = BN_dup(A))  == NULL) goto err;
 149                 }
 150         if (Ai != NULL)
 151                 {
 152                 if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;
 153                 }
 154         ret->mod = mod;
 155         ret->counter = BN_BLINDING_COUNTER;
 156         return(ret);
 157 err:
 158         if (ret != NULL) BN_BLINDING_free(ret);
 159         return(NULL);
 160         }
 161
 162 void BN_BLINDING_free(BN_BLINDING *r)
 163         {
 164         if(r == NULL)
 165             return;
 166
 167         if (r->A  != NULL) BN_free(r->A );
 168         if (r->Ai != NULL) BN_free(r->Ai);
 169         if (r->e  != NULL) BN_free(r->e );
 170         OPENSSL_free(r);
 171         }
 172
 173 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
 174         {
 175         int ret=0;
 176
 177         if ((b->A == NULL) || (b->Ai == NULL))
 178                 {
 179                 BNerr(BN_F_BN_BLINDING_UPDATE,BN_R_NOT_INITIALIZED);
 180                 goto err;
 181                 }
 182
 183         if (--(b->counter) == 0 && b->e != NULL &&
 184                 !(b->flags & BN_BLINDING_NO_RECREATE))
 185                 {
 186                 /* re-create blinding parameters */
 187                 if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
 188                         goto err;
 189                 }
 190         else if (!(b->flags & BN_BLINDING_NO_UPDATE))
 191                 {
 192                 if (!BN_mod_mul(b->A,b->A,b->A,b->mod,ctx)) goto err;
 193                 if (!BN_mod_mul(b->Ai,b->Ai,b->Ai,b->mod,ctx)) goto err;
 194                 }
 195
 196         ret=1;
 197 err:
 198         if (b->counter == 0)
 199                 b->counter = BN_BLINDING_COUNTER;
 200         return(ret);
 201         }
 202
 203 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 204         {
 205         return BN_BLINDING_convert_ex(n, NULL, b, ctx);
 206         }
 207
 208 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
 209         {
 210         int ret = 1;
 211
 212         bn_check_top(n);
 213
 214         if ((b->A == NULL) || (b->Ai == NULL))
 215                 {
 216                 BNerr(BN_F_BN_BLINDING_CONVERT_EX,BN_R_NOT_INITIALIZED);
 217                 return(0);
 218                 }
 219
 220         if (r != NULL)
 221                 {
 222                 if (!BN_copy(r, b->Ai)) ret=0;
 223                 }
 224
 225         if (!BN_mod_mul(n,n,b->A,b->mod,ctx)) ret=0;
 226
 227         return ret;
 228         }
 229
 230 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
 231         {
 232         return BN_BLINDING_invert_ex(n, NULL, b, ctx);
 233         }
 234
 235 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
 236         {
 237         int ret;
 238
 239         bn_check_top(n);
 240         if ((b->A == NULL) || (b->Ai == NULL))
 241                 {
 242                 BNerr(BN_F_BN_BLINDING_INVERT_EX,BN_R_NOT_INITIALIZED);
 243                 return(0);
 244                 }
 245
 246         if (r != NULL)
 247                 ret = BN_mod_mul(n, n, r, b->mod, ctx);
 248         else
 249                 ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
 250
 251         if (ret >= 0)
 252                 {
 253                 if (!BN_BLINDING_update(b,ctx))
 254                         return(0);
 255                 }
 256         bn_check_top(n);
 257         return(ret);
 258         }
 259
 260 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
 261         {
 262         return b->thread_id;
 263         }
 264
 265 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
 266         {
 267         b->thread_id = n;
 268         }
 269
 270 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
 271         {
 272         return b->flags;
 273         }
 274
 275 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
 276         {
 277         b->flags = flags;
 278         }
 279
 280 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
 281         const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
 282         int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
 283                           const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
 284         BN_MONT_CTX *m_ctx)
 285 {
 286         int    retry_counter = 32;
 287         BN_BLINDING *ret = NULL;
 288
 289         if (b == NULL)
 290                 ret = BN_BLINDING_new(NULL, NULL, m);
 291         else
 292                 ret = b;
 293
 294         if (ret == NULL)
 295                 goto err;
 296
 297         if (ret->A  == NULL && (ret->A  = BN_new()) == NULL)
 298                 goto err;
 299         if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
 300                 goto err;
 301
 302         if (e != NULL)
 303                 {
 304                 if (ret->e != NULL)
 305                         BN_free(ret->e);
 306                 ret->e = BN_dup(e);
 307                 }
 308         if (ret->e == NULL)
 309                 goto err;
 310
 311         if (bn_mod_exp != NULL)
 312                 ret->bn_mod_exp = bn_mod_exp;
 313         if (m_ctx != NULL)
 314                 ret->m_ctx = m_ctx;
 315
 316         do {
 317                 if (!BN_rand_range(ret->A, ret->mod)) goto err;
 318                 if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL)
 319                         {
 320                         /* this should almost never happen for good RSA keys */
 321                         unsigned long error = ERR_peek_last_error();
 322                         if (ERR_GET_REASON(error) == BN_R_NO_INVERSE)
 323                                 {
 324                                 if (retry_counter-- == 0)
 325                                 {
 326                                         BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
 327                                                 BN_R_TOO_MANY_ITERATIONS);
 328                                         goto err;
 329                                 }
 330                                 ERR_clear_error();
 331                                 }
 332                         else
 333                                 goto err;
 334                         }
 335                 else
 336                         break;
 337         } while (1);
 338
 339         if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL)
 340                 {
 341                 if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
 342                         goto err;
 343                 }
 344         else
 345                 {
 346                 if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
 347                         goto err;
 348                 }
 349
 350         return ret;
 351 err:
 352         if (b == NULL && ret != NULL)
 353                 {
 354                 BN_BLINDING_free(ret);
 355                 ret = NULL;
 356                 }
 357
 358         return ret;
 359 }