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
70 const 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 */
84 static int bn_limit_bits = 0;
85 static int bn_limit_num = 8; /* (1<<bn_limit_bits) */
86 static int bn_limit_bits_low = 0;
87 static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
88 static int bn_limit_bits_high = 0;
89 static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
90 static int bn_limit_bits_mont = 0;
91 static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
92
BN_set_params(int mult,int high,int low,int mont)93 void 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
BN_get_params(int which)121 int 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
BN_value_one(void)136 const 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
BN_num_bits_word(BN_ULONG l)144 int 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
BN_num_bits(const BIGNUM * a)216 int 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
BN_clear_free(BIGNUM * a)226 void 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
BN_free(BIGNUM * a)244 void 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
BN_init(BIGNUM * a)261 void BN_init(BIGNUM *a)
262 {
263 memset(a, 0, sizeof(BIGNUM));
264 bn_check_top(a);
265 }
266
BN_new(void)267 BIGNUM *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 */
bn_expand_internal(const BIGNUM * b,int words)286 static 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
bn_dup_expand(const BIGNUM * b,int words)377 BIGNUM *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
bn_expand2(BIGNUM * b,int words)425 BIGNUM *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
BN_dup(const BIGNUM * a)466 BIGNUM *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
BN_copy(BIGNUM * a,const BIGNUM * b)485 BIGNUM *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
BN_swap(BIGNUM * a,BIGNUM * b)532 void 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
BN_clear(BIGNUM * a)567 void 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
BN_get_word(const BIGNUM * a)576 BN_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
BN_set_word(BIGNUM * a,BN_ULONG w)586 int 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
BN_bin2bn(const unsigned char * s,int len,BIGNUM * ret)598 BIGNUM *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 */
BN_bn2bin(const BIGNUM * a,unsigned char * to)642 int 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
BN_ucmp(const BIGNUM * a,const BIGNUM * b)656 int 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
BN_cmp(const BIGNUM * a,const BIGNUM * b)678 int 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
BN_set_bit(BIGNUM * a,int n)725 int 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
BN_clear_bit(BIGNUM * a,int n)747 int 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
BN_is_bit_set(const BIGNUM * a,int n)765 int 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
BN_mask_bits(BIGNUM * a,int n)779 int 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
BN_set_negative(BIGNUM * a,int b)801 void 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
bn_cmp_words(const BN_ULONG * a,const BN_ULONG * b,int n)809 int 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
bn_cmp_part_words(const BN_ULONG * a,const BN_ULONG * b,int cl,int dl)836 int 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