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 <openssl/local/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/* For a 32 bit machine 75 * 2 - 4 == 128 76 * 3 - 8 == 256 77 * 4 - 16 == 512 78 * 5 - 32 == 1024 79 * 6 - 64 == 2048 80 * 7 - 128 == 4096 81 * 8 - 256 == 8192 82 */ 83static int bn_limit_bits=0; 84static int bn_limit_num=8; /* (1<<bn_limit_bits) */ 85static int bn_limit_bits_low=0; 86static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */ 87static int bn_limit_bits_high=0; 88static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */ 89static int bn_limit_bits_mont=0; 90static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */ 91 92void BN_set_params(int mult, int high, int low, int mont) 93 { 94 if (mult >= 0) 95 { 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 { 103 if (high > (int)(sizeof(int)*8)-1) 104 high=sizeof(int)*8-1; 105 bn_limit_bits_high=high; 106 bn_limit_num_high=1<<high; 107 } 108 if (low >= 0) 109 { 110 if (low > (int)(sizeof(int)*8)-1) 111 low=sizeof(int)*8-1; 112 bn_limit_bits_low=low; 113 bn_limit_num_low=1<<low; 114 } 115 if (mont >= 0) 116 { 117 if (mont > (int)(sizeof(int)*8)-1) 118 mont=sizeof(int)*8-1; 119 bn_limit_bits_mont=mont; 120 bn_limit_num_mont=1<<mont; 121 } 122 } 123 124int BN_get_params(int which) 125 { 126 if (which == 0) return(bn_limit_bits); 127 else if (which == 1) return(bn_limit_bits_high); 128 else if (which == 2) return(bn_limit_bits_low); 129 else if (which == 3) return(bn_limit_bits_mont); 130 else return(0); 131 } 132#endif 133 134const BIGNUM *BN_value_one(void) 135 { 136 static const BN_ULONG data_one=1L; 137 static const BIGNUM const_one={(BN_ULONG *)&data_one,1,1,0,BN_FLG_STATIC_DATA}; 138 139 return(&const_one); 140 } 141 142char *BN_options(void) 143 { 144 static int init=0; 145 static char data[16]; 146 147 if (!init) 148 { 149 init++; 150#ifdef BN_LLONG 151 BIO_snprintf(data,sizeof data,"bn(%d,%d)", 152 (int)sizeof(BN_ULLONG)*8,(int)sizeof(BN_ULONG)*8); 153#else 154 BIO_snprintf(data,sizeof data,"bn(%d,%d)", 155 (int)sizeof(BN_ULONG)*8,(int)sizeof(BN_ULONG)*8); 156#endif 157 } 158 return(data); 159 } 160 161int BN_num_bits_word(BN_ULONG l) 162 { 163 static const unsigned char bits[256]={ 164 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4, 165 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 166 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 167 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 168 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 169 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 170 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 171 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 172 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 173 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 174 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 175 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 176 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 177 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 178 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 179 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, 180 }; 181 182#if defined(SIXTY_FOUR_BIT_LONG) 183 if (l & 0xffffffff00000000L) 184 { 185 if (l & 0xffff000000000000L) 186 { 187 if (l & 0xff00000000000000L) 188 { 189 return(bits[(int)(l>>56)]+56); 190 } 191 else return(bits[(int)(l>>48)]+48); 192 } 193 else 194 { 195 if (l & 0x0000ff0000000000L) 196 { 197 return(bits[(int)(l>>40)]+40); 198 } 199 else return(bits[(int)(l>>32)]+32); 200 } 201 } 202 else 203#else 204#ifdef SIXTY_FOUR_BIT 205 if (l & 0xffffffff00000000LL) 206 { 207 if (l & 0xffff000000000000LL) 208 { 209 if (l & 0xff00000000000000LL) 210 { 211 return(bits[(int)(l>>56)]+56); 212 } 213 else return(bits[(int)(l>>48)]+48); 214 } 215 else 216 { 217 if (l & 0x0000ff0000000000LL) 218 { 219 return(bits[(int)(l>>40)]+40); 220 } 221 else return(bits[(int)(l>>32)]+32); 222 } 223 } 224 else 225#endif 226#endif 227 { 228#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG) 229 if (l & 0xffff0000L) 230 { 231 if (l & 0xff000000L) 232 return(bits[(int)(l>>24L)]+24); 233 else return(bits[(int)(l>>16L)]+16); 234 } 235 else 236#endif 237 { 238#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG) 239 if (l & 0xff00L) 240 return(bits[(int)(l>>8)]+8); 241 else 242#endif 243 return(bits[(int)(l )] ); 244 } 245 } 246 } 247 248int BN_num_bits(const BIGNUM *a) 249 { 250 int i = a->top - 1; 251 bn_check_top(a); 252 253 if (BN_is_zero(a)) return 0; 254 return ((i*BN_BITS2) + BN_num_bits_word(a->d[i])); 255 } 256 257void BN_clear_free(BIGNUM *a) 258 { 259 int i; 260 261 if (a == NULL) return; 262 bn_check_top(a); 263 if (a->d != NULL) 264 { 265 OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0])); 266 if (!(BN_get_flags(a,BN_FLG_STATIC_DATA))) 267 OPENSSL_free(a->d); 268 } 269 i=BN_get_flags(a,BN_FLG_MALLOCED); 270 OPENSSL_cleanse(a,sizeof(BIGNUM)); 271 if (i) 272 OPENSSL_free(a); 273 } 274 275void BN_free(BIGNUM *a) 276 { 277 if (a == NULL) return; 278 bn_check_top(a); 279 if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA))) 280 OPENSSL_free(a->d); 281 if (a->flags & BN_FLG_MALLOCED) 282 OPENSSL_free(a); 283 else 284 { 285#ifndef OPENSSL_NO_DEPRECATED 286 a->flags|=BN_FLG_FREE; 287#endif 288 a->d = NULL; 289 } 290 } 291 292void BN_init(BIGNUM *a) 293 { 294 memset(a,0,sizeof(BIGNUM)); 295 bn_check_top(a); 296 } 297 298BIGNUM *BN_new(void) 299 { 300 BIGNUM *ret; 301 302 if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL) 303 { 304 BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE); 305 return(NULL); 306 } 307 ret->flags=BN_FLG_MALLOCED; 308 ret->top=0; 309 ret->neg=0; 310 ret->dmax=0; 311 ret->d=NULL; 312 bn_check_top(ret); 313 return(ret); 314 } 315 316/* This is used both by bn_expand2() and bn_dup_expand() */ 317/* The caller MUST check that words > b->dmax before calling this */ 318static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words) 319 { 320 BN_ULONG *A,*a = NULL; 321 const BN_ULONG *B; 322 int i; 323 324 bn_check_top(b); 325 326 if (words > (INT_MAX/(4*BN_BITS2))) 327 { 328 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG); 329 return NULL; 330 } 331 if (BN_get_flags(b,BN_FLG_STATIC_DATA)) 332 { 333 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA); 334 return(NULL); 335 } 336 a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*words); 337 if (A == NULL) 338 { 339 BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE); 340 return(NULL); 341 } 342#if 1 343 B=b->d; 344 /* Check if the previous number needs to be copied */ 345 if (B != NULL) 346 { 347 for (i=b->top>>2; i>0; i--,A+=4,B+=4) 348 { 349 /* 350 * The fact that the loop is unrolled 351 * 4-wise is a tribute to Intel. It's 352 * the one that doesn't have enough 353 * registers to accomodate more data. 354 * I'd unroll it 8-wise otherwise:-) 355 * 356 * <appro@fy.chalmers.se> 357 */ 358 BN_ULONG a0,a1,a2,a3; 359 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3]; 360 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3; 361 } 362 switch (b->top&3) 363 { 364 case 3: A[2]=B[2]; 365 case 2: A[1]=B[1]; 366 case 1: A[0]=B[0]; 367 case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does 368 * the switch table by doing a=top&3; a--; goto jump_table[a]; 369 * which fails for top== 0 */ 370 ; 371 } 372 } 373 374#else 375 memset(A,0,sizeof(BN_ULONG)*words); 376 memcpy(A,b->d,sizeof(b->d[0])*b->top); 377#endif 378 379 return(a); 380 } 381 382/* This is an internal function that can be used instead of bn_expand2() 383 * when there is a need to copy BIGNUMs instead of only expanding the 384 * data part, while still expanding them. 385 * Especially useful when needing to expand BIGNUMs that are declared 386 * 'const' and should therefore not be changed. 387 * The reason to use this instead of a BN_dup() followed by a bn_expand2() 388 * is memory allocation overhead. A BN_dup() followed by a bn_expand2() 389 * will allocate new memory for the BIGNUM data twice, and free it once, 390 * while bn_dup_expand() makes sure allocation is made only once. 391 */ 392 393#ifndef OPENSSL_NO_DEPRECATED 394BIGNUM *bn_dup_expand(const BIGNUM *b, int words) 395 { 396 BIGNUM *r = NULL; 397 398 bn_check_top(b); 399 400 /* This function does not work if 401 * words <= b->dmax && top < words 402 * because BN_dup() does not preserve 'dmax'! 403 * (But bn_dup_expand() is not used anywhere yet.) 404 */ 405 406 if (words > b->dmax) 407 { 408 BN_ULONG *a = bn_expand_internal(b, words); 409 410 if (a) 411 { 412 r = BN_new(); 413 if (r) 414 { 415 r->top = b->top; 416 r->dmax = words; 417 r->neg = b->neg; 418 r->d = a; 419 } 420 else 421 { 422 /* r == NULL, BN_new failure */ 423 OPENSSL_free(a); 424 } 425 } 426 /* If a == NULL, there was an error in allocation in 427 bn_expand_internal(), and NULL should be returned */ 428 } 429 else 430 { 431 r = BN_dup(b); 432 } 433 434 bn_check_top(r); 435 return r; 436 } 437#endif 438 439/* This is an internal function that should not be used in applications. 440 * It ensures that 'b' has enough room for a 'words' word number 441 * and initialises any unused part of b->d with leading zeros. 442 * It is mostly used by the various BIGNUM routines. If there is an error, 443 * NULL is returned. If not, 'b' is returned. */ 444 445BIGNUM *bn_expand2(BIGNUM *b, int words) 446 { 447 bn_check_top(b); 448 449 if (words > b->dmax) 450 { 451 BN_ULONG *a = bn_expand_internal(b, words); 452 if(!a) return NULL; 453 if(b->d) OPENSSL_free(b->d); 454 b->d=a; 455 b->dmax=words; 456 } 457 458/* None of this should be necessary because of what b->top means! */ 459#if 0 460 /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */ 461 if (b->top < b->dmax) 462 { 463 int i; 464 BN_ULONG *A = &(b->d[b->top]); 465 for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8) 466 { 467 A[0]=0; A[1]=0; A[2]=0; A[3]=0; 468 A[4]=0; A[5]=0; A[6]=0; A[7]=0; 469 } 470 for (i=(b->dmax - b->top)&7; i>0; i--,A++) 471 A[0]=0; 472 assert(A == &(b->d[b->dmax])); 473 } 474#endif 475 bn_check_top(b); 476 return b; 477 } 478 479BIGNUM *BN_dup(const BIGNUM *a) 480 { 481 BIGNUM *t; 482 483 if (a == NULL) return NULL; 484 bn_check_top(a); 485 486 t = BN_new(); 487 if (t == NULL) return NULL; 488 if(!BN_copy(t, a)) 489 { 490 BN_free(t); 491 return NULL; 492 } 493 bn_check_top(t); 494 return t; 495 } 496 497BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b) 498 { 499 int i; 500 BN_ULONG *A; 501 const BN_ULONG *B; 502 503 bn_check_top(b); 504 505 if (a == b) return(a); 506 if (bn_wexpand(a,b->top) == NULL) return(NULL); 507 508#if 1 509 A=a->d; 510 B=b->d; 511 for (i=b->top>>2; i>0; i--,A+=4,B+=4) 512 { 513 BN_ULONG a0,a1,a2,a3; 514 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3]; 515 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3; 516 } 517 switch (b->top&3) 518 { 519 case 3: A[2]=B[2]; 520 case 2: A[1]=B[1]; 521 case 1: A[0]=B[0]; 522 case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */ 523 } 524#else 525 memcpy(a->d,b->d,sizeof(b->d[0])*b->top); 526#endif 527 528 a->top=b->top; 529 a->neg=b->neg; 530 bn_check_top(a); 531 return(a); 532 } 533 534void BN_swap(BIGNUM *a, BIGNUM *b) 535 { 536 int flags_old_a, flags_old_b; 537 BN_ULONG *tmp_d; 538 int tmp_top, tmp_dmax, tmp_neg; 539 540 bn_check_top(a); 541 bn_check_top(b); 542 543 flags_old_a = a->flags; 544 flags_old_b = b->flags; 545 546 tmp_d = a->d; 547 tmp_top = a->top; 548 tmp_dmax = a->dmax; 549 tmp_neg = a->neg; 550 551 a->d = b->d; 552 a->top = b->top; 553 a->dmax = b->dmax; 554 a->neg = b->neg; 555 556 b->d = tmp_d; 557 b->top = tmp_top; 558 b->dmax = tmp_dmax; 559 b->neg = tmp_neg; 560 561 a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA); 562 b->flags = (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) return(0); 590 a->neg = 0; 591 a->d[0] = w; 592 a->top = (w ? 1 : 0); 593 bn_check_top(a); 594 return(1); 595 } 596 597BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret) 598 { 599 unsigned int i,m; 600 unsigned int n; 601 BN_ULONG l; 602 BIGNUM *bn = NULL; 603 604 if (ret == NULL) 605 ret = bn = BN_new(); 606 if (ret == NULL) return(NULL); 607 bn_check_top(ret); 608 l=0; 609 n=len; 610 if (n == 0) 611 { 612 ret->top=0; 613 return(ret); 614 } 615 i=((n-1)/BN_BYTES)+1; 616 m=((n-1)%(BN_BYTES)); 617 if (bn_wexpand(ret, (int)i) == NULL) 618 { 619 if (bn) BN_free(bn); 620 return NULL; 621 } 622 ret->top=i; 623 ret->neg=0; 624 while (n--) 625 { 626 l=(l<<8L)| *(s++); 627 if (m-- == 0) 628 { 629 ret->d[--i]=l; 630 l=0; 631 m=BN_BYTES-1; 632 } 633 } 634 /* need to call this due to clear byte at top if avoiding 635 * having the top bit set (-ve number) */ 636 bn_correct_top(ret); 637 return(ret); 638 } 639 640/* ignore negative */ 641int BN_bn2bin(const BIGNUM *a, unsigned char *to) 642 { 643 int n,i; 644 BN_ULONG l; 645 646 bn_check_top(a); 647 n=i=BN_num_bytes(a); 648 while (i--) 649 { 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) return(i); 666 ap=a->d; 667 bp=b->d; 668 for (i=a->top-1; i>=0; i--) 669 { 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 { 686 if (a != NULL) 687 return(-1); 688 else if (b != NULL) 689 return(1); 690 else 691 return(0); 692 } 693 694 bn_check_top(a); 695 bn_check_top(b); 696 697 if (a->neg != b->neg) 698 { 699 if (a->neg) 700 return(-1); 701 else return(1); 702 } 703 if (a->neg == 0) 704 { gt=1; lt= -1; } 705 else { gt= -1; lt=1; } 706 707 if (a->top > b->top) return(gt); 708 if (a->top < b->top) return(lt); 709 for (i=a->top-1; i>=0; i--) 710 { 711 t1=a->d[i]; 712 t2=b->d[i]; 713 if (t1 > t2) return(gt); 714 if (t1 < t2) return(lt); 715 } 716 return(0); 717 } 718 719int BN_set_bit(BIGNUM *a, int n) 720 { 721 int i,j,k; 722 723 if (n < 0) 724 return 0; 725 726 i=n/BN_BITS2; 727 j=n%BN_BITS2; 728 if (a->top <= i) 729 { 730 if (bn_wexpand(a,i+1) == NULL) return(0); 731 for(k=a->top; k<i+1; k++) 732 a->d[k]=0; 733 a->top=i+1; 734 } 735 736 a->d[i]|=(((BN_ULONG)1)<<j); 737 bn_check_top(a); 738 return(1); 739 } 740 741int BN_clear_bit(BIGNUM *a, int n) 742 { 743 int i,j; 744 745 bn_check_top(a); 746 if (n < 0) return 0; 747 748 i=n/BN_BITS2; 749 j=n%BN_BITS2; 750 if (a->top <= i) return(0); 751 752 a->d[i]&=(~(((BN_ULONG)1)<<j)); 753 bn_correct_top(a); 754 return(1); 755 } 756 757int BN_is_bit_set(const BIGNUM *a, int n) 758 { 759 int i,j; 760 761 bn_check_top(a); 762 if (n < 0) return 0; 763 i=n/BN_BITS2; 764 j=n%BN_BITS2; 765 if (a->top <= i) return 0; 766 return (int)(((a->d[i])>>j)&((BN_ULONG)1)); 767 } 768 769int BN_mask_bits(BIGNUM *a, int n) 770 { 771 int b,w; 772 773 bn_check_top(a); 774 if (n < 0) return 0; 775 776 w=n/BN_BITS2; 777 b=n%BN_BITS2; 778 if (w >= a->top) return 0; 779 if (b == 0) 780 a->top=w; 781 else 782 { 783 a->top=w+1; 784 a->d[w]&= ~(BN_MASK2<<b); 785 } 786 bn_correct_top(a); 787 return(1); 788 } 789 790void BN_set_negative(BIGNUM *a, int b) 791 { 792 if (b && !BN_is_zero(a)) 793 a->neg = 1; 794 else 795 a->neg = 0; 796 } 797 798int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n) 799 { 800 int i; 801 BN_ULONG aa,bb; 802 803 aa=a[n-1]; 804 bb=b[n-1]; 805 if (aa != bb) return((aa > bb)?1:-1); 806 for (i=n-2; i>=0; i--) 807 { 808 aa=a[i]; 809 bb=b[i]; 810 if (aa != bb) return((aa > bb)?1:-1); 811 } 812 return(0); 813 } 814 815/* Here follows a specialised variants of bn_cmp_words(). It has the 816 property of performing the operation on arrays of different sizes. 817 The sizes of those arrays is expressed through cl, which is the 818 common length ( basicall, min(len(a),len(b)) ), and dl, which is the 819 delta between the two lengths, calculated as len(a)-len(b). 820 All lengths are the number of BN_ULONGs... */ 821 822int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, 823 int cl, int dl) 824 { 825 int n,i; 826 n = cl-1; 827 828 if (dl < 0) 829 { 830 for (i=dl; i<0; i++) 831 { 832 if (b[n-i] != 0) 833 return -1; /* a < b */ 834 } 835 } 836 if (dl > 0) 837 { 838 for (i=dl; i>0; i--) 839 { 840 if (a[n+i] != 0) 841 return 1; /* a > b */ 842 } 843 } 844 return bn_cmp_words(a,b,cl); 845 } 846