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 <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 BIGNUM *A; 120 BIGNUM *Ai; 121 BIGNUM *e; 122 BIGNUM *mod; /* just a reference */ 123 #ifndef OPENSSL_NO_DEPRECATED 124 unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b; used 125 * only by crypto/rsa/rsa_eay.c, rsa_lib.c */ 126 #endif 127 CRYPTO_THREADID tid; 128 int counter; 129 unsigned long flags; 130 BN_MONT_CTX *m_ctx; 131 int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p, 132 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); 133 }; 134 135 BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod) 136 { 137 BN_BLINDING *ret = NULL; 138 139 bn_check_top(mod); 140 141 if ((ret = (BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL) { 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 if ((ret->A = BN_dup(A)) == NULL) 148 goto err; 149 } 150 if (Ai != NULL) { 151 if ((ret->Ai = BN_dup(Ai)) == NULL) 152 goto err; 153 } 154 155 /* save a copy of mod in the BN_BLINDING structure */ 156 if ((ret->mod = BN_dup(mod)) == NULL) 157 goto err; 158 if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0) 159 BN_set_flags(ret->mod, BN_FLG_CONSTTIME); 160 161 /* 162 * Set the counter to the special value -1 to indicate that this is 163 * never-used fresh blinding that does not need updating before first 164 * use. 165 */ 166 ret->counter = -1; 167 CRYPTO_THREADID_current(&ret->tid); 168 return (ret); 169 err: 170 if (ret != NULL) 171 BN_BLINDING_free(ret); 172 return (NULL); 173 } 174 175 void BN_BLINDING_free(BN_BLINDING *r) 176 { 177 if (r == NULL) 178 return; 179 180 if (r->A != NULL) 181 BN_free(r->A); 182 if (r->Ai != NULL) 183 BN_free(r->Ai); 184 if (r->e != NULL) 185 BN_free(r->e); 186 if (r->mod != NULL) 187 BN_free(r->mod); 188 OPENSSL_free(r); 189 } 190 191 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx) 192 { 193 int ret = 0; 194 195 if ((b->A == NULL) || (b->Ai == NULL)) { 196 BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED); 197 goto err; 198 } 199 200 if (b->counter == -1) 201 b->counter = 0; 202 203 if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL && 204 !(b->flags & BN_BLINDING_NO_RECREATE)) { 205 /* re-create blinding parameters */ 206 if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL)) 207 goto err; 208 } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) { 209 if (!BN_mod_mul(b->A, b->A, b->A, b->mod, ctx)) 210 goto err; 211 if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)) 212 goto err; 213 } 214 215 ret = 1; 216 err: 217 if (b->counter == BN_BLINDING_COUNTER) 218 b->counter = 0; 219 return (ret); 220 } 221 222 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx) 223 { 224 return BN_BLINDING_convert_ex(n, NULL, b, ctx); 225 } 226 227 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx) 228 { 229 int ret = 1; 230 231 bn_check_top(n); 232 233 if ((b->A == NULL) || (b->Ai == NULL)) { 234 BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED); 235 return (0); 236 } 237 238 if (b->counter == -1) 239 /* Fresh blinding, doesn't need updating. */ 240 b->counter = 0; 241 else if (!BN_BLINDING_update(b, ctx)) 242 return (0); 243 244 if (r != NULL) { 245 if (!BN_copy(r, b->Ai)) 246 ret = 0; 247 } 248 249 if (!BN_mod_mul(n, n, b->A, b->mod, ctx)) 250 ret = 0; 251 252 return ret; 253 } 254 255 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx) 256 { 257 return BN_BLINDING_invert_ex(n, NULL, b, ctx); 258 } 259 260 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, 261 BN_CTX *ctx) 262 { 263 int ret; 264 265 bn_check_top(n); 266 267 if (r != NULL) 268 ret = BN_mod_mul(n, n, r, b->mod, ctx); 269 else { 270 if (b->Ai == NULL) { 271 BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED); 272 return (0); 273 } 274 ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx); 275 } 276 277 bn_check_top(n); 278 return (ret); 279 } 280 281 #ifndef OPENSSL_NO_DEPRECATED 282 unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b) 283 { 284 return b->thread_id; 285 } 286 287 void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n) 288 { 289 b->thread_id = n; 290 } 291 #endif 292 293 CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *b) 294 { 295 return &b->tid; 296 } 297 298 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b) 299 { 300 return b->flags; 301 } 302 303 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags) 304 { 305 b->flags = flags; 306 } 307 308 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b, 309 const BIGNUM *e, BIGNUM *m, BN_CTX *ctx, 310 int (*bn_mod_exp) (BIGNUM *r, 311 const BIGNUM *a, 312 const BIGNUM *p, 313 const BIGNUM *m, 314 BN_CTX *ctx, 315 BN_MONT_CTX *m_ctx), 316 BN_MONT_CTX *m_ctx) 317 { 318 int retry_counter = 32; 319 BN_BLINDING *ret = NULL; 320 321 if (b == NULL) 322 ret = BN_BLINDING_new(NULL, NULL, m); 323 else 324 ret = b; 325 326 if (ret == NULL) 327 goto err; 328 329 if (ret->A == NULL && (ret->A = BN_new()) == NULL) 330 goto err; 331 if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL) 332 goto err; 333 334 if (e != NULL) { 335 if (ret->e != NULL) 336 BN_free(ret->e); 337 ret->e = BN_dup(e); 338 } 339 if (ret->e == NULL) 340 goto err; 341 342 if (bn_mod_exp != NULL) 343 ret->bn_mod_exp = bn_mod_exp; 344 if (m_ctx != NULL) 345 ret->m_ctx = m_ctx; 346 347 do { 348 if (!BN_rand_range(ret->A, ret->mod)) 349 goto err; 350 if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL) { 351 /* 352 * this should almost never happen for good RSA keys 353 */ 354 unsigned long error = ERR_peek_last_error(); 355 if (ERR_GET_REASON(error) == BN_R_NO_INVERSE) { 356 if (retry_counter-- == 0) { 357 BNerr(BN_F_BN_BLINDING_CREATE_PARAM, 358 BN_R_TOO_MANY_ITERATIONS); 359 goto err; 360 } 361 ERR_clear_error(); 362 } else 363 goto err; 364 } else 365 break; 366 } while (1); 367 368 if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) { 369 if (!ret->bn_mod_exp 370 (ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx)) 371 goto err; 372 } else { 373 if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx)) 374 goto err; 375 } 376 377 return ret; 378 err: 379 if (b == NULL && ret != NULL) { 380 BN_BLINDING_free(ret); 381 ret = NULL; 382 } 383 384 return ret; 385 } 386