bn_blind.c revision 296465
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 118struct bn_blinding_st { 119 BIGNUM *A; 120 BIGNUM *Ai; 121 BIGNUM *e; 122 BIGNUM *mod; /* just a reference */ 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 int counter; 126 unsigned long flags; 127 BN_MONT_CTX *m_ctx; 128 int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p, 129 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); 130}; 131 132BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod) 133{ 134 BN_BLINDING *ret = NULL; 135 136 bn_check_top(mod); 137 138 if ((ret = (BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL) { 139 BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE); 140 return (NULL); 141 } 142 memset(ret, 0, sizeof(BN_BLINDING)); 143 if (A != NULL) { 144 if ((ret->A = BN_dup(A)) == NULL) 145 goto err; 146 } 147 if (Ai != NULL) { 148 if ((ret->Ai = BN_dup(Ai)) == NULL) 149 goto err; 150 } 151 152 /* save a copy of mod in the BN_BLINDING structure */ 153 if ((ret->mod = BN_dup(mod)) == NULL) 154 goto err; 155 if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0) 156 BN_set_flags(ret->mod, BN_FLG_CONSTTIME); 157 158 /* 159 * Set the counter to the special value -1 to indicate that this is 160 * never-used fresh blinding that does not need updating before first 161 * use. 162 */ 163 ret->counter = -1; 164 return (ret); 165 err: 166 if (ret != NULL) 167 BN_BLINDING_free(ret); 168 return (NULL); 169} 170 171void BN_BLINDING_free(BN_BLINDING *r) 172{ 173 if (r == NULL) 174 return; 175 176 if (r->A != NULL) 177 BN_free(r->A); 178 if (r->Ai != NULL) 179 BN_free(r->Ai); 180 if (r->e != NULL) 181 BN_free(r->e); 182 if (r->mod != NULL) 183 BN_free(r->mod); 184 OPENSSL_free(r); 185} 186 187int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx) 188{ 189 int ret = 0; 190 191 if ((b->A == NULL) || (b->Ai == NULL)) { 192 BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED); 193 goto err; 194 } 195 196 if (b->counter == -1) 197 b->counter = 0; 198 199 if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL && 200 !(b->flags & BN_BLINDING_NO_RECREATE)) { 201 /* re-create blinding parameters */ 202 if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL)) 203 goto err; 204 } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) { 205 if (!BN_mod_mul(b->A, b->A, b->A, b->mod, ctx)) 206 goto err; 207 if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)) 208 goto err; 209 } 210 211 ret = 1; 212 err: 213 if (b->counter == BN_BLINDING_COUNTER) 214 b->counter = 0; 215 return (ret); 216} 217 218int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx) 219{ 220 return BN_BLINDING_convert_ex(n, NULL, b, ctx); 221} 222 223int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx) 224{ 225 int ret = 1; 226 227 bn_check_top(n); 228 229 if ((b->A == NULL) || (b->Ai == NULL)) { 230 BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED); 231 return (0); 232 } 233 234 if (b->counter == -1) 235 /* Fresh blinding, doesn't need updating. */ 236 b->counter = 0; 237 else if (!BN_BLINDING_update(b, ctx)) 238 return (0); 239 240 if (r != NULL) { 241 if (!BN_copy(r, b->Ai)) 242 ret = 0; 243 } 244 245 if (!BN_mod_mul(n, n, b->A, b->mod, ctx)) 246 ret = 0; 247 248 return ret; 249} 250 251int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx) 252{ 253 return BN_BLINDING_invert_ex(n, NULL, b, ctx); 254} 255 256int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, 257 BN_CTX *ctx) 258{ 259 int ret; 260 261 bn_check_top(n); 262 263 if (r != NULL) 264 ret = BN_mod_mul(n, n, r, b->mod, ctx); 265 else { 266 if (b->Ai == NULL) { 267 BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED); 268 return (0); 269 } 270 ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx); 271 } 272 273 bn_check_top(n); 274 return (ret); 275} 276 277unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b) 278{ 279 return b->thread_id; 280} 281 282void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n) 283{ 284 b->thread_id = n; 285} 286 287unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b) 288{ 289 return b->flags; 290} 291 292void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags) 293{ 294 b->flags = flags; 295} 296 297BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b, 298 const BIGNUM *e, BIGNUM *m, BN_CTX *ctx, 299 int (*bn_mod_exp) (BIGNUM *r, 300 const BIGNUM *a, 301 const BIGNUM *p, 302 const BIGNUM *m, 303 BN_CTX *ctx, 304 BN_MONT_CTX *m_ctx), 305 BN_MONT_CTX *m_ctx) 306{ 307 int retry_counter = 32; 308 BN_BLINDING *ret = NULL; 309 310 if (b == NULL) 311 ret = BN_BLINDING_new(NULL, NULL, m); 312 else 313 ret = b; 314 315 if (ret == NULL) 316 goto err; 317 318 if (ret->A == NULL && (ret->A = BN_new()) == NULL) 319 goto err; 320 if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL) 321 goto err; 322 323 if (e != NULL) { 324 if (ret->e != NULL) 325 BN_free(ret->e); 326 ret->e = BN_dup(e); 327 } 328 if (ret->e == NULL) 329 goto err; 330 331 if (bn_mod_exp != NULL) 332 ret->bn_mod_exp = bn_mod_exp; 333 if (m_ctx != NULL) 334 ret->m_ctx = m_ctx; 335 336 do { 337 if (!BN_rand_range(ret->A, ret->mod)) 338 goto err; 339 if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL) { 340 /* 341 * this should almost never happen for good RSA keys 342 */ 343 unsigned long error = ERR_peek_last_error(); 344 if (ERR_GET_REASON(error) == BN_R_NO_INVERSE) { 345 if (retry_counter-- == 0) { 346 BNerr(BN_F_BN_BLINDING_CREATE_PARAM, 347 BN_R_TOO_MANY_ITERATIONS); 348 goto err; 349 } 350 ERR_clear_error(); 351 } else 352 goto err; 353 } else 354 break; 355 } while (1); 356 357 if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) { 358 if (!ret->bn_mod_exp 359 (ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx)) 360 goto err; 361 } else { 362 if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx)) 363 goto err; 364 } 365 366 return ret; 367 err: 368 if (b == NULL && ret != NULL) { 369 BN_BLINDING_free(ret); 370 ret = NULL; 371 } 372 373 return ret; 374} 375