bn_lib.c revision 296465
1/* crypto/bn/bn_lib.c */ 2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 59#ifndef BN_DEBUG 60# undef NDEBUG /* avoid conflicting definitions */ 61# define NDEBUG 62#endif 63 64#include <assert.h> 65#include <limits.h> 66#include <stdio.h> 67#include "cryptlib.h" 68#include "bn_lcl.h" 69 70const char BN_version[] = "Big Number" OPENSSL_VERSION_PTEXT; 71 72/* This stuff appears to be completely unused, so is deprecated */ 73#ifndef OPENSSL_NO_DEPRECATED 74/*- 75 * For a 32 bit machine 76 * 2 - 4 == 128 77 * 3 - 8 == 256 78 * 4 - 16 == 512 79 * 5 - 32 == 1024 80 * 6 - 64 == 2048 81 * 7 - 128 == 4096 82 * 8 - 256 == 8192 83 */ 84static int bn_limit_bits = 0; 85static int bn_limit_num = 8; /* (1<<bn_limit_bits) */ 86static int bn_limit_bits_low = 0; 87static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */ 88static int bn_limit_bits_high = 0; 89static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */ 90static int bn_limit_bits_mont = 0; 91static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */ 92 93void BN_set_params(int mult, int high, int low, int mont) 94{ 95 if (mult >= 0) { 96 if (mult > (int)(sizeof(int) * 8) - 1) 97 mult = sizeof(int) * 8 - 1; 98 bn_limit_bits = mult; 99 bn_limit_num = 1 << mult; 100 } 101 if (high >= 0) { 102 if (high > (int)(sizeof(int) * 8) - 1) 103 high = sizeof(int) * 8 - 1; 104 bn_limit_bits_high = high; 105 bn_limit_num_high = 1 << high; 106 } 107 if (low >= 0) { 108 if (low > (int)(sizeof(int) * 8) - 1) 109 low = sizeof(int) * 8 - 1; 110 bn_limit_bits_low = low; 111 bn_limit_num_low = 1 << low; 112 } 113 if (mont >= 0) { 114 if (mont > (int)(sizeof(int) * 8) - 1) 115 mont = sizeof(int) * 8 - 1; 116 bn_limit_bits_mont = mont; 117 bn_limit_num_mont = 1 << mont; 118 } 119} 120 121int BN_get_params(int which) 122{ 123 if (which == 0) 124 return (bn_limit_bits); 125 else if (which == 1) 126 return (bn_limit_bits_high); 127 else if (which == 2) 128 return (bn_limit_bits_low); 129 else if (which == 3) 130 return (bn_limit_bits_mont); 131 else 132 return (0); 133} 134#endif 135 136const BIGNUM *BN_value_one(void) 137{ 138 static BN_ULONG data_one = 1L; 139 static BIGNUM const_one = { &data_one, 1, 1, 0, BN_FLG_STATIC_DATA }; 140 141 return (&const_one); 142} 143 144int BN_num_bits_word(BN_ULONG l) 145{ 146 static const char bits[256] = { 147 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 148 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 149 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 150 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 151 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 152 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 153 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 154 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 155 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 156 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 157 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 158 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 159 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 160 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 161 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 162 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 163 }; 164 165#if defined(SIXTY_FOUR_BIT_LONG) 166 if (l & 0xffffffff00000000L) { 167 if (l & 0xffff000000000000L) { 168 if (l & 0xff00000000000000L) { 169 return (bits[(int)(l >> 56)] + 56); 170 } else 171 return (bits[(int)(l >> 48)] + 48); 172 } else { 173 if (l & 0x0000ff0000000000L) { 174 return (bits[(int)(l >> 40)] + 40); 175 } else 176 return (bits[(int)(l >> 32)] + 32); 177 } 178 } else 179#else 180# ifdef SIXTY_FOUR_BIT 181 if (l & 0xffffffff00000000LL) { 182 if (l & 0xffff000000000000LL) { 183 if (l & 0xff00000000000000LL) { 184 return (bits[(int)(l >> 56)] + 56); 185 } else 186 return (bits[(int)(l >> 48)] + 48); 187 } else { 188 if (l & 0x0000ff0000000000LL) { 189 return (bits[(int)(l >> 40)] + 40); 190 } else 191 return (bits[(int)(l >> 32)] + 32); 192 } 193 } else 194# endif 195#endif 196 { 197#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG) 198 if (l & 0xffff0000L) { 199 if (l & 0xff000000L) 200 return (bits[(int)(l >> 24L)] + 24); 201 else 202 return (bits[(int)(l >> 16L)] + 16); 203 } else 204#endif 205 { 206#if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG) 207 if (l & 0xff00L) 208 return (bits[(int)(l >> 8)] + 8); 209 else 210#endif 211 return (bits[(int)(l)]); 212 } 213 } 214} 215 216int BN_num_bits(const BIGNUM *a) 217{ 218 int i = a->top - 1; 219 bn_check_top(a); 220 221 if (BN_is_zero(a)) 222 return 0; 223 return ((i * BN_BITS2) + BN_num_bits_word(a->d[i])); 224} 225 226void BN_clear_free(BIGNUM *a) 227{ 228 int i; 229 230 if (a == NULL) 231 return; 232 bn_check_top(a); 233 if (a->d != NULL) { 234 OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0])); 235 if (!(BN_get_flags(a, BN_FLG_STATIC_DATA))) 236 OPENSSL_free(a->d); 237 } 238 i = BN_get_flags(a, BN_FLG_MALLOCED); 239 OPENSSL_cleanse(a, sizeof(BIGNUM)); 240 if (i) 241 OPENSSL_free(a); 242} 243 244void BN_free(BIGNUM *a) 245{ 246 if (a == NULL) 247 return; 248 bn_check_top(a); 249 if ((a->d != NULL) && !(BN_get_flags(a, BN_FLG_STATIC_DATA))) 250 OPENSSL_free(a->d); 251 if (a->flags & BN_FLG_MALLOCED) 252 OPENSSL_free(a); 253 else { 254#ifndef OPENSSL_NO_DEPRECATED 255 a->flags |= BN_FLG_FREE; 256#endif 257 a->d = NULL; 258 } 259} 260 261void BN_init(BIGNUM *a) 262{ 263 memset(a, 0, sizeof(BIGNUM)); 264 bn_check_top(a); 265} 266 267BIGNUM *BN_new(void) 268{ 269 BIGNUM *ret; 270 271 if ((ret = (BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL) { 272 BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE); 273 return (NULL); 274 } 275 ret->flags = BN_FLG_MALLOCED; 276 ret->top = 0; 277 ret->neg = 0; 278 ret->dmax = 0; 279 ret->d = NULL; 280 bn_check_top(ret); 281 return (ret); 282} 283 284/* This is used both by bn_expand2() and bn_dup_expand() */ 285/* The caller MUST check that words > b->dmax before calling this */ 286static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words) 287{ 288 BN_ULONG *A, *a = NULL; 289 const BN_ULONG *B; 290 int i; 291 292 bn_check_top(b); 293 294 if (words > (INT_MAX / (4 * BN_BITS2))) { 295 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG); 296 return NULL; 297 } 298 if (BN_get_flags(b, BN_FLG_STATIC_DATA)) { 299 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA); 300 return (NULL); 301 } 302 a = A = (BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG) * words); 303 if (A == NULL) { 304 BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE); 305 return (NULL); 306 } 307#ifdef PURIFY 308 /* 309 * Valgrind complains in BN_consttime_swap because we process the whole 310 * array even if it's not initialised yet. This doesn't matter in that 311 * function - what's important is constant time operation (we're not 312 * actually going to use the data) 313 */ 314 memset(a, 0, sizeof(BN_ULONG) * words); 315#endif 316 317#if 1 318 B = b->d; 319 /* Check if the previous number needs to be copied */ 320 if (B != NULL) { 321 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) { 322 /* 323 * The fact that the loop is unrolled 324 * 4-wise is a tribute to Intel. It's 325 * the one that doesn't have enough 326 * registers to accomodate more data. 327 * I'd unroll it 8-wise otherwise:-) 328 * 329 * <appro@fy.chalmers.se> 330 */ 331 BN_ULONG a0, a1, a2, a3; 332 a0 = B[0]; 333 a1 = B[1]; 334 a2 = B[2]; 335 a3 = B[3]; 336 A[0] = a0; 337 A[1] = a1; 338 A[2] = a2; 339 A[3] = a3; 340 } 341 /* 342 * workaround for ultrix cc: without 'case 0', the optimizer does 343 * the switch table by doing a=top&3; a--; goto jump_table[a]; 344 * which fails for top== 0 345 */ 346 switch (b->top & 3) { 347 case 3: 348 A[2] = B[2]; 349 case 2: 350 A[1] = B[1]; 351 case 1: 352 A[0] = B[0]; 353 case 0: 354 ; 355 } 356 } 357#else 358 memset(A, 0, sizeof(BN_ULONG) * words); 359 memcpy(A, b->d, sizeof(b->d[0]) * b->top); 360#endif 361 362 return (a); 363} 364 365/* 366 * This is an internal function that can be used instead of bn_expand2() when 367 * there is a need to copy BIGNUMs instead of only expanding the data part, 368 * while still expanding them. Especially useful when needing to expand 369 * BIGNUMs that are declared 'const' and should therefore not be changed. The 370 * reason to use this instead of a BN_dup() followed by a bn_expand2() is 371 * memory allocation overhead. A BN_dup() followed by a bn_expand2() will 372 * allocate new memory for the BIGNUM data twice, and free it once, while 373 * bn_dup_expand() makes sure allocation is made only once. 374 */ 375 376#ifndef OPENSSL_NO_DEPRECATED 377BIGNUM *bn_dup_expand(const BIGNUM *b, int words) 378{ 379 BIGNUM *r = NULL; 380 381 bn_check_top(b); 382 383 /* 384 * This function does not work if words <= b->dmax && top < words because 385 * BN_dup() does not preserve 'dmax'! (But bn_dup_expand() is not used 386 * anywhere yet.) 387 */ 388 389 if (words > b->dmax) { 390 BN_ULONG *a = bn_expand_internal(b, words); 391 392 if (a) { 393 r = BN_new(); 394 if (r) { 395 r->top = b->top; 396 r->dmax = words; 397 r->neg = b->neg; 398 r->d = a; 399 } else { 400 /* r == NULL, BN_new failure */ 401 OPENSSL_free(a); 402 } 403 } 404 /* 405 * If a == NULL, there was an error in allocation in 406 * bn_expand_internal(), and NULL should be returned 407 */ 408 } else { 409 r = BN_dup(b); 410 } 411 412 bn_check_top(r); 413 return r; 414} 415#endif 416 417/* 418 * This is an internal function that should not be used in applications. It 419 * ensures that 'b' has enough room for a 'words' word number and initialises 420 * any unused part of b->d with leading zeros. It is mostly used by the 421 * various BIGNUM routines. If there is an error, NULL is returned. If not, 422 * 'b' is returned. 423 */ 424 425BIGNUM *bn_expand2(BIGNUM *b, int words) 426{ 427 bn_check_top(b); 428 429 if (words > b->dmax) { 430 BN_ULONG *a = bn_expand_internal(b, words); 431 if (!a) 432 return NULL; 433 if (b->d) 434 OPENSSL_free(b->d); 435 b->d = a; 436 b->dmax = words; 437 } 438 439/* None of this should be necessary because of what b->top means! */ 440#if 0 441 /* 442 * NB: bn_wexpand() calls this only if the BIGNUM really has to grow 443 */ 444 if (b->top < b->dmax) { 445 int i; 446 BN_ULONG *A = &(b->d[b->top]); 447 for (i = (b->dmax - b->top) >> 3; i > 0; i--, A += 8) { 448 A[0] = 0; 449 A[1] = 0; 450 A[2] = 0; 451 A[3] = 0; 452 A[4] = 0; 453 A[5] = 0; 454 A[6] = 0; 455 A[7] = 0; 456 } 457 for (i = (b->dmax - b->top) & 7; i > 0; i--, A++) 458 A[0] = 0; 459 assert(A == &(b->d[b->dmax])); 460 } 461#endif 462 bn_check_top(b); 463 return b; 464} 465 466BIGNUM *BN_dup(const BIGNUM *a) 467{ 468 BIGNUM *t; 469 470 if (a == NULL) 471 return NULL; 472 bn_check_top(a); 473 474 t = BN_new(); 475 if (t == NULL) 476 return NULL; 477 if (!BN_copy(t, a)) { 478 BN_free(t); 479 return NULL; 480 } 481 bn_check_top(t); 482 return t; 483} 484 485BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b) 486{ 487 int i; 488 BN_ULONG *A; 489 const BN_ULONG *B; 490 491 bn_check_top(b); 492 493 if (a == b) 494 return (a); 495 if (bn_wexpand(a, b->top) == NULL) 496 return (NULL); 497 498#if 1 499 A = a->d; 500 B = b->d; 501 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) { 502 BN_ULONG a0, a1, a2, a3; 503 a0 = B[0]; 504 a1 = B[1]; 505 a2 = B[2]; 506 a3 = B[3]; 507 A[0] = a0; 508 A[1] = a1; 509 A[2] = a2; 510 A[3] = a3; 511 } 512 /* ultrix cc workaround, see comments in bn_expand_internal */ 513 switch (b->top & 3) { 514 case 3: 515 A[2] = B[2]; 516 case 2: 517 A[1] = B[1]; 518 case 1: 519 A[0] = B[0]; 520 case 0:; 521 } 522#else 523 memcpy(a->d, b->d, sizeof(b->d[0]) * b->top); 524#endif 525 526 a->top = b->top; 527 a->neg = b->neg; 528 bn_check_top(a); 529 return (a); 530} 531 532void BN_swap(BIGNUM *a, BIGNUM *b) 533{ 534 int flags_old_a, flags_old_b; 535 BN_ULONG *tmp_d; 536 int tmp_top, tmp_dmax, tmp_neg; 537 538 bn_check_top(a); 539 bn_check_top(b); 540 541 flags_old_a = a->flags; 542 flags_old_b = b->flags; 543 544 tmp_d = a->d; 545 tmp_top = a->top; 546 tmp_dmax = a->dmax; 547 tmp_neg = a->neg; 548 549 a->d = b->d; 550 a->top = b->top; 551 a->dmax = b->dmax; 552 a->neg = b->neg; 553 554 b->d = tmp_d; 555 b->top = tmp_top; 556 b->dmax = tmp_dmax; 557 b->neg = tmp_neg; 558 559 a->flags = 560 (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA); 561 b->flags = 562 (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA); 563 bn_check_top(a); 564 bn_check_top(b); 565} 566 567void BN_clear(BIGNUM *a) 568{ 569 bn_check_top(a); 570 if (a->d != NULL) 571 memset(a->d, 0, a->dmax * sizeof(a->d[0])); 572 a->top = 0; 573 a->neg = 0; 574} 575 576BN_ULONG BN_get_word(const BIGNUM *a) 577{ 578 if (a->top > 1) 579 return BN_MASK2; 580 else if (a->top == 1) 581 return a->d[0]; 582 /* a->top == 0 */ 583 return 0; 584} 585 586int BN_set_word(BIGNUM *a, BN_ULONG w) 587{ 588 bn_check_top(a); 589 if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL) 590 return (0); 591 a->neg = 0; 592 a->d[0] = w; 593 a->top = (w ? 1 : 0); 594 bn_check_top(a); 595 return (1); 596} 597 598BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret) 599{ 600 unsigned int i, m; 601 unsigned int n; 602 BN_ULONG l; 603 BIGNUM *bn = NULL; 604 605 if (ret == NULL) 606 ret = bn = BN_new(); 607 if (ret == NULL) 608 return (NULL); 609 bn_check_top(ret); 610 l = 0; 611 n = len; 612 if (n == 0) { 613 ret->top = 0; 614 return (ret); 615 } 616 i = ((n - 1) / BN_BYTES) + 1; 617 m = ((n - 1) % (BN_BYTES)); 618 if (bn_wexpand(ret, (int)i) == NULL) { 619 if (bn) 620 BN_free(bn); 621 return NULL; 622 } 623 ret->top = i; 624 ret->neg = 0; 625 while (n--) { 626 l = (l << 8L) | *(s++); 627 if (m-- == 0) { 628 ret->d[--i] = l; 629 l = 0; 630 m = BN_BYTES - 1; 631 } 632 } 633 /* 634 * need to call this due to clear byte at top if avoiding having the top 635 * bit set (-ve number) 636 */ 637 bn_correct_top(ret); 638 return (ret); 639} 640 641/* ignore negative */ 642int BN_bn2bin(const BIGNUM *a, unsigned char *to) 643{ 644 int n, i; 645 BN_ULONG l; 646 647 bn_check_top(a); 648 n = i = BN_num_bytes(a); 649 while (i--) { 650 l = a->d[i / BN_BYTES]; 651 *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff; 652 } 653 return (n); 654} 655 656int BN_ucmp(const BIGNUM *a, const BIGNUM *b) 657{ 658 int i; 659 BN_ULONG t1, t2, *ap, *bp; 660 661 bn_check_top(a); 662 bn_check_top(b); 663 664 i = a->top - b->top; 665 if (i != 0) 666 return (i); 667 ap = a->d; 668 bp = b->d; 669 for (i = a->top - 1; i >= 0; i--) { 670 t1 = ap[i]; 671 t2 = bp[i]; 672 if (t1 != t2) 673 return ((t1 > t2) ? 1 : -1); 674 } 675 return (0); 676} 677 678int BN_cmp(const BIGNUM *a, const BIGNUM *b) 679{ 680 int i; 681 int gt, lt; 682 BN_ULONG t1, t2; 683 684 if ((a == NULL) || (b == NULL)) { 685 if (a != NULL) 686 return (-1); 687 else if (b != NULL) 688 return (1); 689 else 690 return (0); 691 } 692 693 bn_check_top(a); 694 bn_check_top(b); 695 696 if (a->neg != b->neg) { 697 if (a->neg) 698 return (-1); 699 else 700 return (1); 701 } 702 if (a->neg == 0) { 703 gt = 1; 704 lt = -1; 705 } else { 706 gt = -1; 707 lt = 1; 708 } 709 710 if (a->top > b->top) 711 return (gt); 712 if (a->top < b->top) 713 return (lt); 714 for (i = a->top - 1; i >= 0; i--) { 715 t1 = a->d[i]; 716 t2 = b->d[i]; 717 if (t1 > t2) 718 return (gt); 719 if (t1 < t2) 720 return (lt); 721 } 722 return (0); 723} 724 725int BN_set_bit(BIGNUM *a, int n) 726{ 727 int i, j, k; 728 729 if (n < 0) 730 return 0; 731 732 i = n / BN_BITS2; 733 j = n % BN_BITS2; 734 if (a->top <= i) { 735 if (bn_wexpand(a, i + 1) == NULL) 736 return (0); 737 for (k = a->top; k < i + 1; k++) 738 a->d[k] = 0; 739 a->top = i + 1; 740 } 741 742 a->d[i] |= (((BN_ULONG)1) << j); 743 bn_check_top(a); 744 return (1); 745} 746 747int BN_clear_bit(BIGNUM *a, int n) 748{ 749 int i, j; 750 751 bn_check_top(a); 752 if (n < 0) 753 return 0; 754 755 i = n / BN_BITS2; 756 j = n % BN_BITS2; 757 if (a->top <= i) 758 return (0); 759 760 a->d[i] &= (~(((BN_ULONG)1) << j)); 761 bn_correct_top(a); 762 return (1); 763} 764 765int BN_is_bit_set(const BIGNUM *a, int n) 766{ 767 int i, j; 768 769 bn_check_top(a); 770 if (n < 0) 771 return 0; 772 i = n / BN_BITS2; 773 j = n % BN_BITS2; 774 if (a->top <= i) 775 return 0; 776 return (((a->d[i]) >> j) & ((BN_ULONG)1)); 777} 778 779int BN_mask_bits(BIGNUM *a, int n) 780{ 781 int b, w; 782 783 bn_check_top(a); 784 if (n < 0) 785 return 0; 786 787 w = n / BN_BITS2; 788 b = n % BN_BITS2; 789 if (w >= a->top) 790 return 0; 791 if (b == 0) 792 a->top = w; 793 else { 794 a->top = w + 1; 795 a->d[w] &= ~(BN_MASK2 << b); 796 } 797 bn_correct_top(a); 798 return (1); 799} 800 801void BN_set_negative(BIGNUM *a, int b) 802{ 803 if (b && !BN_is_zero(a)) 804 a->neg = 1; 805 else 806 a->neg = 0; 807} 808 809int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n) 810{ 811 int i; 812 BN_ULONG aa, bb; 813 814 aa = a[n - 1]; 815 bb = b[n - 1]; 816 if (aa != bb) 817 return ((aa > bb) ? 1 : -1); 818 for (i = n - 2; i >= 0; i--) { 819 aa = a[i]; 820 bb = b[i]; 821 if (aa != bb) 822 return ((aa > bb) ? 1 : -1); 823 } 824 return (0); 825} 826 827/* 828 * Here follows a specialised variants of bn_cmp_words(). It has the 829 * property of performing the operation on arrays of different sizes. The 830 * sizes of those arrays is expressed through cl, which is the common length 831 * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the 832 * two lengths, calculated as len(a)-len(b). All lengths are the number of 833 * BN_ULONGs... 834 */ 835 836int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl) 837{ 838 int n, i; 839 n = cl - 1; 840 841 if (dl < 0) { 842 for (i = dl; i < 0; i++) { 843 if (b[n - i] != 0) 844 return -1; /* a < b */ 845 } 846 } 847 if (dl > 0) { 848 for (i = dl; i > 0; i--) { 849 if (a[n + i] != 0) 850 return 1; /* a > b */ 851 } 852 } 853 return bn_cmp_words(a, b, cl); 854} 855