1 /* $OpenBSD: bn_blind.c,v 1.13 2014/07/11 08:44:47 jsing Exp $ */ 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> 113 114 #include <openssl/opensslconf.h> 115 116 #include <openssl/err.h> 117 118 #include "bn_lcl.h" 119 120 #define BN_BLINDING_COUNTER 32 121 122 struct bn_blinding_st { 123 BIGNUM *A; 124 BIGNUM *Ai; 125 BIGNUM *e; 126 BIGNUM *mod; /* just a reference */ 127 #ifndef OPENSSL_NO_DEPRECATED 128 unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b; 129 * used only by crypto/rsa/rsa_eay.c, rsa_lib.c */ 130 #endif 131 CRYPTO_THREADID tid; 132 int counter; 133 unsigned long flags; 134 BN_MONT_CTX *m_ctx; 135 int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, 136 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); 137 }; 138 139 BN_BLINDING * 140 BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod) 141 { 142 BN_BLINDING *ret = NULL; 143 144 bn_check_top(mod); 145 146 if ((ret = calloc(1, sizeof(BN_BLINDING))) == NULL) { 147 BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE); 148 return (NULL); 149 } 150 if (A != NULL) { 151 if ((ret->A = BN_dup(A)) == NULL) 152 goto err; 153 } 154 if (Ai != NULL) { 155 if ((ret->Ai = BN_dup(Ai)) == NULL) 156 goto err; 157 } 158 159 /* save a copy of mod in the BN_BLINDING structure */ 160 if ((ret->mod = BN_dup(mod)) == NULL) 161 goto err; 162 if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0) 163 BN_set_flags(ret->mod, BN_FLG_CONSTTIME); 164 165 /* Set the counter to the special value -1 166 * to indicate that this is never-used fresh blinding 167 * that does not need updating before first use. */ 168 ret->counter = -1; 169 CRYPTO_THREADID_current(&ret->tid); 170 return (ret); 171 172 err: 173 if (ret != NULL) 174 BN_BLINDING_free(ret); 175 return (NULL); 176 } 177 178 void 179 BN_BLINDING_free(BN_BLINDING *r) 180 { 181 if (r == NULL) 182 return; 183 184 BN_clear_free(r->A); 185 BN_clear_free(r->Ai); 186 BN_clear_free(r->e); 187 BN_clear_free(r->mod); 188 free(r); 189 } 190 191 int 192 BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx) 193 { 194 int ret = 0; 195 196 if ((b->A == NULL) || (b->Ai == NULL)) { 197 BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED); 198 goto err; 199 } 200 201 if (b->counter == -1) 202 b->counter = 0; 203 204 if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL && 205 !(b->flags & BN_BLINDING_NO_RECREATE)) { 206 /* re-create blinding parameters */ 207 if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL)) 208 goto err; 209 } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) { 210 if (!BN_mod_mul(b->A, b->A, b->A, b->mod, ctx)) 211 goto err; 212 if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)) 213 goto err; 214 } 215 216 ret = 1; 217 218 err: 219 if (b->counter == BN_BLINDING_COUNTER) 220 b->counter = 0; 221 return (ret); 222 } 223 224 int 225 BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx) 226 { 227 return BN_BLINDING_convert_ex(n, NULL, b, ctx); 228 } 229 230 int 231 BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx) 232 { 233 int ret = 1; 234 235 bn_check_top(n); 236 237 if ((b->A == NULL) || (b->Ai == NULL)) { 238 BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED); 239 return (0); 240 } 241 242 if (b->counter == -1) 243 /* Fresh blinding, doesn't need updating. */ 244 b->counter = 0; 245 else if (!BN_BLINDING_update(b, ctx)) 246 return (0); 247 248 if (r != NULL) { 249 if (!BN_copy(r, b->Ai)) 250 ret = 0; 251 } 252 253 if (!BN_mod_mul(n, n,b->A, b->mod, ctx)) 254 ret = 0; 255 256 return ret; 257 } 258 259 int 260 BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx) 261 { 262 return BN_BLINDING_invert_ex(n, NULL, b, ctx); 263 } 264 265 int 266 BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx) 267 { 268 int ret; 269 270 bn_check_top(n); 271 272 if (r != NULL) 273 ret = BN_mod_mul(n, n, r, b->mod, ctx); 274 else { 275 if (b->Ai == NULL) { 276 BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED); 277 return (0); 278 } 279 ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx); 280 } 281 282 bn_check_top(n); 283 return (ret); 284 } 285 286 #ifndef OPENSSL_NO_DEPRECATED 287 unsigned long 288 BN_BLINDING_get_thread_id(const BN_BLINDING *b) 289 { 290 return b->thread_id; 291 } 292 293 void 294 BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n) 295 { 296 b->thread_id = n; 297 } 298 #endif 299 300 CRYPTO_THREADID * 301 BN_BLINDING_thread_id(BN_BLINDING *b) 302 { 303 return &b->tid; 304 } 305 306 unsigned long 307 BN_BLINDING_get_flags(const BN_BLINDING *b) 308 { 309 return b->flags; 310 } 311 312 void 313 BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags) 314 { 315 b->flags = flags; 316 } 317 318 BN_BLINDING * 319 BN_BLINDING_create_param(BN_BLINDING *b, const BIGNUM *e, BIGNUM *m, 320 BN_CTX *ctx, int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, 321 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx), BN_MONT_CTX *m_ctx) 322 { 323 int retry_counter = 32; 324 BN_BLINDING *ret = NULL; 325 326 if (b == NULL) 327 ret = BN_BLINDING_new(NULL, NULL, m); 328 else 329 ret = b; 330 331 if (ret == NULL) 332 goto err; 333 334 if (ret->A == NULL && (ret->A = BN_new()) == NULL) 335 goto err; 336 if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL) 337 goto err; 338 339 if (e != NULL) { 340 BN_free(ret->e); 341 ret->e = BN_dup(e); 342 } 343 if (ret->e == NULL) 344 goto err; 345 346 if (bn_mod_exp != NULL) 347 ret->bn_mod_exp = bn_mod_exp; 348 if (m_ctx != NULL) 349 ret->m_ctx = m_ctx; 350 351 do { 352 if (!BN_rand_range(ret->A, ret->mod)) 353 goto err; 354 if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL) { 355 /* this should almost never happen for good RSA keys */ 356 unsigned long error = ERR_peek_last_error(); 357 if (ERR_GET_REASON(error) == BN_R_NO_INVERSE) { 358 if (retry_counter-- == 0) { 359 BNerr(BN_F_BN_BLINDING_CREATE_PARAM, 360 BN_R_TOO_MANY_ITERATIONS); 361 goto err; 362 } 363 ERR_clear_error(); 364 } else 365 goto err; 366 } else 367 break; 368 } while (1); 369 370 if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) { 371 if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, 372 ctx, ret->m_ctx)) 373 goto err; 374 } else { 375 if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx)) 376 goto err; 377 } 378 379 return ret; 380 381 err: 382 if (b == NULL && ret != NULL) { 383 BN_BLINDING_free(ret); 384 ret = NULL; 385 } 386 387 return ret; 388 } 389