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