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| 1 /* crypto/bn/bn_mod.c */ | |
| 2 /* Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de> | |
| 3 * for the OpenSSL project. */ | |
| 4 /* ==================================================================== | |
| 5 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved. | |
| 6 * | |
| 7 * Redistribution and use in source and binary forms, with or without | |
| 8 * modification, are permitted provided that the following conditions | |
| 9 * are met: | |
| 10 * | |
| 11 * 1. Redistributions of source code must retain the above copyright | |
| 12 * notice, this list of conditions and the following disclaimer. | |
| 13 * | |
| 14 * 2. Redistributions in binary form must reproduce the above copyright | |
| 15 * notice, this list of conditions and the following disclaimer in | |
| 16 * the documentation and/or other materials provided with the | |
| 17 * distribution. | |
| 18 * | |
| 19 * 3. All advertising materials mentioning features or use of this | |
| 20 * software must display the following acknowledgment: | |
| 21 * "This product includes software developed by the OpenSSL Project | |
| 22 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |
| 23 * | |
| 24 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
| 25 * endorse or promote products derived from this software without | |
| 26 * prior written permission. For written permission, please contact | |
| 27 * openssl-core@openssl.org. | |
| 28 * | |
| 29 * 5. Products derived from this software may not be called "OpenSSL" | |
| 30 * nor may "OpenSSL" appear in their names without prior written | |
| 31 * permission of the OpenSSL Project. | |
| 32 * | |
| 33 * 6. Redistributions of any form whatsoever must retain the following | |
| 34 * acknowledgment: | |
| 35 * "This product includes software developed by the OpenSSL Project | |
| 36 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |
| 37 * | |
| 38 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
| 39 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 40 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
| 41 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
| 42 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 43 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 44 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 45 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
| 47 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 48 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
| 49 * OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 50 * ==================================================================== | |
| 51 * | |
| 52 * This product includes cryptographic software written by Eric Young | |
| 53 * (eay@cryptsoft.com). This product includes software written by Tim | |
| 54 * Hudson (tjh@cryptsoft.com). | |
| 55 * | |
| 56 */ | |
| 57 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |
| 58 * All rights reserved. | |
| 59 * | |
| 60 * This package is an SSL implementation written | |
| 61 * by Eric Young (eay@cryptsoft.com). | |
| 62 * The implementation was written so as to conform with Netscapes SSL. | |
| 63 * | |
| 64 * This library is free for commercial and non-commercial use as long as | |
| 65 * the following conditions are aheared to. The following conditions | |
| 66 * apply to all code found in this distribution, be it the RC4, RSA, | |
| 67 * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
| 68 * included with this distribution is covered by the same copyright terms | |
| 69 * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
| 70 * | |
| 71 * Copyright remains Eric Young's, and as such any Copyright notices in | |
| 72 * the code are not to be removed. | |
| 73 * If this package is used in a product, Eric Young should be given attribution | |
| 74 * as the author of the parts of the library used. | |
| 75 * This can be in the form of a textual message at program startup or | |
| 76 * in documentation (online or textual) provided with the package. | |
| 77 * | |
| 78 * Redistribution and use in source and binary forms, with or without | |
| 79 * modification, are permitted provided that the following conditions | |
| 80 * are met: | |
| 81 * 1. Redistributions of source code must retain the copyright | |
| 82 * notice, this list of conditions and the following disclaimer. | |
| 83 * 2. Redistributions in binary form must reproduce the above copyright | |
| 84 * notice, this list of conditions and the following disclaimer in the | |
| 85 * documentation and/or other materials provided with the distribution. | |
| 86 * 3. All advertising materials mentioning features or use of this software | |
| 87 * must display the following acknowledgement: | |
| 88 * "This product includes cryptographic software written by | |
| 89 * Eric Young (eay@cryptsoft.com)" | |
| 90 * The word 'cryptographic' can be left out if the rouines from the library | |
| 91 * being used are not cryptographic related :-). | |
| 92 * 4. If you include any Windows specific code (or a derivative thereof) from | |
| 93 * the apps directory (application code) you must include an acknowledgement: | |
| 94 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
| 95 * | |
| 96 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |
| 97 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 98 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 99 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
| 100 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 101 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 102 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 103 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 104 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 105 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 106 * SUCH DAMAGE. | |
| 107 * | |
| 108 * The licence and distribution terms for any publically available version or | |
| 109 * derivative of this code cannot be changed. i.e. this code cannot simply be | |
| 110 * copied and put under another distribution licence | |
| 111 * [including the GNU Public Licence.] | |
| 112 */ | |
| 113 | |
| 114 #include "cryptlib.h" | |
| 115 #include "bn_lcl.h" | |
| 116 | |
| 117 | |
| 118 #if 0 /* now just a #define */ | |
| 119 int BN_mod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx) | |
| 120 { | |
| 121 return(BN_div(NULL,rem,m,d,ctx)); | |
| 122 /* note that rem->neg == m->neg (unless the remainder is zero) */ | |
| 123 } | |
| 124 #endif | |
| 125 | |
| 126 | |
| 127 int BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx) | |
| 128 { | |
| 129 /* like BN_mod, but returns non-negative remainder | |
| 130 * (i.e., 0 <= r < |d| always holds) */ | |
| 131 | |
| 132 if (!(BN_mod(r,m,d,ctx))) | |
| 133 return 0; | |
| 134 if (!r->neg) | |
| 135 return 1; | |
| 136 /* now -|d| < r < 0, so we have to set r := r + |d| */ | |
| 137 return (d->neg ? BN_sub : BN_add)(r, r, d); | |
| 138 } | |
| 139 | |
| 140 | |
| 141 int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, BN_
CTX *ctx) | |
| 142 { | |
| 143 if (!BN_add(r, a, b)) return 0; | |
| 144 return BN_nnmod(r, r, m, ctx); | |
| 145 } | |
| 146 | |
| 147 | |
| 148 /* BN_mod_add variant that may be used if both a and b are non-negative | |
| 149 * and less than m */ | |
| 150 int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *
m) | |
| 151 { | |
| 152 if (!BN_uadd(r, a, b)) return 0; | |
| 153 if (BN_ucmp(r, m) >= 0) | |
| 154 return BN_usub(r, r, m); | |
| 155 return 1; | |
| 156 } | |
| 157 | |
| 158 | |
| 159 int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, BN_
CTX *ctx) | |
| 160 { | |
| 161 if (!BN_sub(r, a, b)) return 0; | |
| 162 return BN_nnmod(r, r, m, ctx); | |
| 163 } | |
| 164 | |
| 165 | |
| 166 /* BN_mod_sub variant that may be used if both a and b are non-negative | |
| 167 * and less than m */ | |
| 168 int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *
m) | |
| 169 { | |
| 170 if (!BN_sub(r, a, b)) return 0; | |
| 171 if (r->neg) | |
| 172 return BN_add(r, r, m); | |
| 173 return 1; | |
| 174 } | |
| 175 | |
| 176 | |
| 177 /* slow but works */ | |
| 178 int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, | |
| 179 BN_CTX *ctx) | |
| 180 { | |
| 181 BIGNUM *t; | |
| 182 int ret=0; | |
| 183 | |
| 184 bn_check_top(a); | |
| 185 bn_check_top(b); | |
| 186 bn_check_top(m); | |
| 187 | |
| 188 BN_CTX_start(ctx); | |
| 189 if ((t = BN_CTX_get(ctx)) == NULL) goto err; | |
| 190 if (a == b) | |
| 191 { if (!BN_sqr(t,a,ctx)) goto err; } | |
| 192 else | |
| 193 { if (!BN_mul(t,a,b,ctx)) goto err; } | |
| 194 if (!BN_nnmod(r,t,m,ctx)) goto err; | |
| 195 bn_check_top(r); | |
| 196 ret=1; | |
| 197 err: | |
| 198 BN_CTX_end(ctx); | |
| 199 return(ret); | |
| 200 } | |
| 201 | |
| 202 | |
| 203 int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx) | |
| 204 { | |
| 205 if (!BN_sqr(r, a, ctx)) return 0; | |
| 206 /* r->neg == 0, thus we don't need BN_nnmod */ | |
| 207 return BN_mod(r, r, m, ctx); | |
| 208 } | |
| 209 | |
| 210 | |
| 211 int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx) | |
| 212 { | |
| 213 if (!BN_lshift1(r, a)) return 0; | |
| 214 bn_check_top(r); | |
| 215 return BN_nnmod(r, r, m, ctx); | |
| 216 } | |
| 217 | |
| 218 | |
| 219 /* BN_mod_lshift1 variant that may be used if a is non-negative | |
| 220 * and less than m */ | |
| 221 int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *m) | |
| 222 { | |
| 223 if (!BN_lshift1(r, a)) return 0; | |
| 224 bn_check_top(r); | |
| 225 if (BN_cmp(r, m) >= 0) | |
| 226 return BN_sub(r, r, m); | |
| 227 return 1; | |
| 228 } | |
| 229 | |
| 230 | |
| 231 int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m, BN_CTX *ct
x) | |
| 232 { | |
| 233 BIGNUM *abs_m = NULL; | |
| 234 int ret; | |
| 235 | |
| 236 if (!BN_nnmod(r, a, m, ctx)) return 0; | |
| 237 | |
| 238 if (m->neg) | |
| 239 { | |
| 240 abs_m = BN_dup(m); | |
| 241 if (abs_m == NULL) return 0; | |
| 242 abs_m->neg = 0; | |
| 243 } | |
| 244 | |
| 245 ret = BN_mod_lshift_quick(r, r, n, (abs_m ? abs_m : m)); | |
| 246 bn_check_top(r); | |
| 247 | |
| 248 if (abs_m) | |
| 249 BN_free(abs_m); | |
| 250 return ret; | |
| 251 } | |
| 252 | |
| 253 | |
| 254 /* BN_mod_lshift variant that may be used if a is non-negative | |
| 255 * and less than m */ | |
| 256 int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m) | |
| 257 { | |
| 258 if (r != a) | |
| 259 { | |
| 260 if (BN_copy(r, a) == NULL) return 0; | |
| 261 } | |
| 262 | |
| 263 while (n > 0) | |
| 264 { | |
| 265 int max_shift; | |
| 266 | |
| 267 /* 0 < r < m */ | |
| 268 max_shift = BN_num_bits(m) - BN_num_bits(r); | |
| 269 /* max_shift >= 0 */ | |
| 270 | |
| 271 if (max_shift < 0) | |
| 272 { | |
| 273 BNerr(BN_F_BN_MOD_LSHIFT_QUICK, BN_R_INPUT_NOT_REDUCED); | |
| 274 return 0; | |
| 275 } | |
| 276 | |
| 277 if (max_shift > n) | |
| 278 max_shift = n; | |
| 279 | |
| 280 if (max_shift) | |
| 281 { | |
| 282 if (!BN_lshift(r, r, max_shift)) return 0; | |
| 283 n -= max_shift; | |
| 284 } | |
| 285 else | |
| 286 { | |
| 287 if (!BN_lshift1(r, r)) return 0; | |
| 288 --n; | |
| 289 } | |
| 290 | |
| 291 /* BN_num_bits(r) <= BN_num_bits(m) */ | |
| 292 | |
| 293 if (BN_cmp(r, m) >= 0) | |
| 294 { | |
| 295 if (!BN_sub(r, r, m)) return 0; | |
| 296 } | |
| 297 } | |
| 298 bn_check_top(r); | |
| 299 | |
| 300 return 1; | |
| 301 } | |
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Chromium Code Reviews
Issue 2072073002:
Delete bundled copy of OpenSSL and replace with README. (Closed)
Base URL: https://chromium.googlesource.com/chromium/deps/openssl@master