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