GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcrypto/ec/ec_mult.c Lines: 255 354 72.0 %
Date: 2017-11-13 Branches: 202 309 65.4 %

Line Branch Exec Source
1
/* $OpenBSD: ec_mult.c,v 1.21 2017/05/02 03:59:44 deraadt Exp $ */
2
/*
3
 * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
4
 */
5
/* ====================================================================
6
 * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
7
 *
8
 * Redistribution and use in source and binary forms, with or without
9
 * modification, are permitted provided that the following conditions
10
 * are met:
11
 *
12
 * 1. Redistributions of source code must retain the above copyright
13
 *    notice, this list of conditions and the following disclaimer.
14
 *
15
 * 2. Redistributions in binary form must reproduce the above copyright
16
 *    notice, this list of conditions and the following disclaimer in
17
 *    the documentation and/or other materials provided with the
18
 *    distribution.
19
 *
20
 * 3. All advertising materials mentioning features or use of this
21
 *    software must display the following acknowledgment:
22
 *    "This product includes software developed by the OpenSSL Project
23
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24
 *
25
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26
 *    endorse or promote products derived from this software without
27
 *    prior written permission. For written permission, please contact
28
 *    openssl-core@openssl.org.
29
 *
30
 * 5. Products derived from this software may not be called "OpenSSL"
31
 *    nor may "OpenSSL" appear in their names without prior written
32
 *    permission of the OpenSSL Project.
33
 *
34
 * 6. Redistributions of any form whatsoever must retain the following
35
 *    acknowledgment:
36
 *    "This product includes software developed by the OpenSSL Project
37
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38
 *
39
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50
 * OF THE POSSIBILITY OF SUCH DAMAGE.
51
 * ====================================================================
52
 *
53
 * This product includes cryptographic software written by Eric Young
54
 * (eay@cryptsoft.com).  This product includes software written by Tim
55
 * Hudson (tjh@cryptsoft.com).
56
 *
57
 */
58
/* ====================================================================
59
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
60
 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
61
 * and contributed to the OpenSSL project.
62
 */
63
64
#include <string.h>
65
66
#include <openssl/err.h>
67
68
#include "ec_lcl.h"
69
70
71
/*
72
 * This file implements the wNAF-based interleaving multi-exponentation method
73
 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>);
74
 * for multiplication with precomputation, we use wNAF splitting
75
 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>).
76
 */
77
78
79
80
81
/* structure for precomputed multiples of the generator */
82
typedef struct ec_pre_comp_st {
83
	const EC_GROUP *group;	/* parent EC_GROUP object */
84
	size_t blocksize;	/* block size for wNAF splitting */
85
	size_t numblocks;	/* max. number of blocks for which we have
86
				 * precomputation */
87
	size_t w;		/* window size */
88
	EC_POINT **points;	/* array with pre-calculated multiples of
89
				 * generator: 'num' pointers to EC_POINT
90
				 * objects followed by a NULL */
91
	size_t num;		/* numblocks * 2^(w-1) */
92
	int references;
93
} EC_PRE_COMP;
94
95
/* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */
96
static void *ec_pre_comp_dup(void *);
97
static void ec_pre_comp_free(void *);
98
static void ec_pre_comp_clear_free(void *);
99
100
static EC_PRE_COMP *
101
ec_pre_comp_new(const EC_GROUP * group)
102
{
103
	EC_PRE_COMP *ret = NULL;
104
105
96
	if (!group)
106
		return NULL;
107
108
48
	ret = malloc(sizeof(EC_PRE_COMP));
109
48
	if (!ret) {
110
		ECerror(ERR_R_MALLOC_FAILURE);
111
		return ret;
112
	}
113
48
	ret->group = group;
114
48
	ret->blocksize = 8;	/* default */
115
48
	ret->numblocks = 0;
116
48
	ret->w = 4;		/* default */
117
48
	ret->points = NULL;
118
48
	ret->num = 0;
119
48
	ret->references = 1;
120
48
	return ret;
121
48
}
122
123
static void *
124
ec_pre_comp_dup(void *src_)
125
{
126
96
	EC_PRE_COMP *src = src_;
127
128
	/* no need to actually copy, these objects never change! */
129
130
48
	CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP);
131
132
48
	return src_;
133
}
134
135
static void
136
ec_pre_comp_free(void *pre_)
137
{
138
	int i;
139
288
	EC_PRE_COMP *pre = pre_;
140
141
144
	if (!pre)
142
48
		return;
143
144
96
	i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
145
96
	if (i > 0)
146
48
		return;
147
148
48
	if (pre->points) {
149
		EC_POINT **p;
150
151
30768
		for (p = pre->points; *p != NULL; p++)
152
15336
			EC_POINT_free(*p);
153
48
		free(pre->points);
154
48
	}
155
48
	free(pre);
156
192
}
157
158
static void
159
ec_pre_comp_clear_free(void *pre_)
160
{
161
	int i;
162
	EC_PRE_COMP *pre = pre_;
163
164
	if (!pre)
165
		return;
166
167
	i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
168
	if (i > 0)
169
		return;
170
171
	if (pre->points) {
172
		EC_POINT **p;
173
174
		for (p = pre->points; *p != NULL; p++) {
175
			EC_POINT_clear_free(*p);
176
			explicit_bzero(p, sizeof *p);
177
		}
178
		free(pre->points);
179
	}
180
	freezero(pre, sizeof *pre);
181
}
182
183
184
185
186
/* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
187
 * This is an array  r[]  of values that are either zero or odd with an
188
 * absolute value less than  2^w  satisfying
189
 *     scalar = \sum_j r[j]*2^j
190
 * where at most one of any  w+1  consecutive digits is non-zero
191
 * with the exception that the most significant digit may be only
192
 * w-1 zeros away from that next non-zero digit.
193
 */
194
static signed char *
195
compute_wNAF(const BIGNUM * scalar, int w, size_t * ret_len)
196
{
197
	int window_val;
198
	int ok = 0;
199
	signed char *r = NULL;
200
	int sign = 1;
201
	int bit, next_bit, mask;
202
	size_t len = 0, j;
203
204
10556
	if (BN_is_zero(scalar)) {
205
3
		r = malloc(1);
206
3
		if (!r) {
207
			ECerror(ERR_R_MALLOC_FAILURE);
208
			goto err;
209
		}
210
3
		r[0] = 0;
211
3
		*ret_len = 1;
212
3
		return r;
213
	}
214
5275
	if (w <= 0 || w > 7) {
215
		/* 'signed char' can represent integers with
216
		 * absolute values less than 2^7 */
217
		ECerror(ERR_R_INTERNAL_ERROR);
218
		goto err;
219
	}
220
5275
	bit = 1 << w;		/* at most 128 */
221
5275
	next_bit = bit << 1;	/* at most 256 */
222
5275
	mask = next_bit - 1;	/* at most 255 */
223
224
5275
	if (BN_is_negative(scalar)) {
225
		sign = -1;
226
45
	}
227

10550
	if (scalar->d == NULL || scalar->top == 0) {
228
		ECerror(ERR_R_INTERNAL_ERROR);
229
		goto err;
230
	}
231
5275
	len = BN_num_bits(scalar);
232
5275
	r = malloc(len + 1);	/* modified wNAF may be one digit longer than
233
				 * binary representation (*ret_len will be
234
				 * set to the actual length, i.e. at most
235
				 * BN_num_bits(scalar) + 1) */
236
5275
	if (r == NULL) {
237
		ECerror(ERR_R_MALLOC_FAILURE);
238
		goto err;
239
	}
240
5275
	window_val = scalar->d[0] & mask;
241
	j = 0;
242

3011651
	while ((window_val != 0) || (j + w + 1 < len)) {
243
		/* if j+w+1 >= len, window_val will not increase */
244
		int digit = 0;
245
246
		/* 0 <= window_val <= 2^(w+1) */
247
1426945
		if (window_val & 1) {
248
			/* 0 < window_val < 2^(w+1) */
249
266419
			if (window_val & bit) {
250
130974
				digit = window_val - next_bit;	/* -2^w < digit < 0 */
251
252
#if 1				/* modified wNAF */
253
130974
				if (j + w + 1 >= len) {
254
					/*
255
					 * special case for generating
256
					 * modified wNAFs: no new bits will
257
					 * be added into window_val, so using
258
					 * a positive digit here will
259
					 * decrease the total length of the
260
					 * representation
261
					 */
262
263
928
					digit = window_val & (mask >> 1);	/* 0 < digit < 2^w */
264
928
				}
265
#endif
266
			} else {
267
				digit = window_val;	/* 0 < digit < 2^w */
268
			}
269
270

799257
			if (digit <= -bit || digit >= bit || !(digit & 1)) {
271
				ECerror(ERR_R_INTERNAL_ERROR);
272
				goto err;
273
			}
274
266419
			window_val -= digit;
275
276
			/*
277
			 * now window_val is 0 or 2^(w+1) in standard wNAF
278
			 * generation; for modified window NAFs, it may also
279
			 * be 2^w
280
			 */
281

398321
			if (window_val != 0 && window_val != next_bit && window_val != bit) {
282
				ECerror(ERR_R_INTERNAL_ERROR);
283
				goto err;
284
			}
285
		}
286
1426945
		r[j++] = sign * digit;
287
288
1426945
		window_val >>= 1;
289
1426945
		window_val += bit * BN_is_bit_set(scalar, j + w);
290
291
1426945
		if (window_val > next_bit) {
292
			ECerror(ERR_R_INTERNAL_ERROR);
293
			goto err;
294
		}
295
1426945
	}
296
297
5275
	if (j > len + 1) {
298
		ECerror(ERR_R_INTERNAL_ERROR);
299
		goto err;
300
	}
301
	len = j;
302
5275
	ok = 1;
303
304
err:
305
5275
	if (!ok) {
306
		free(r);
307
		r = NULL;
308
	}
309
5275
	if (ok)
310
5275
		*ret_len = len;
311
5275
	return r;
312
5278
}
313
314
315
/* TODO: table should be optimised for the wNAF-based implementation,
316
 *       sometimes smaller windows will give better performance
317
 *       (thus the boundaries should be increased)
318
 */
319
#define EC_window_bits_for_scalar_size(b) \
320
		((size_t) \
321
		 ((b) >= 2000 ? 6 : \
322
		  (b) >=  800 ? 5 : \
323
		  (b) >=  300 ? 4 : \
324
		  (b) >=   70 ? 3 : \
325
		  (b) >=   20 ? 2 : \
326
		  1))
327
328
/* Compute
329
 *      \sum scalars[i]*points[i],
330
 * also including
331
 *      scalar*generator
332
 * in the addition if scalar != NULL
333
 */
334
int
335
ec_wNAF_mul(const EC_GROUP * group, EC_POINT * r, const BIGNUM * scalar,
336
    size_t num, const EC_POINT * points[], const BIGNUM * scalars[], BN_CTX * ctx)
337
{
338
	BN_CTX *new_ctx = NULL;
339
	const EC_POINT *generator = NULL;
340
	EC_POINT *tmp = NULL;
341
	size_t totalnum;
342
	size_t blocksize = 0, numblocks = 0;	/* for wNAF splitting */
343
	size_t pre_points_per_block = 0;
344
	size_t i, j;
345
	int k;
346
	int r_is_inverted = 0;
347
	int r_is_at_infinity = 1;
348
	size_t *wsize = NULL;	/* individual window sizes */
349
	signed char **wNAF = NULL;	/* individual wNAFs */
350
	signed char *tmp_wNAF = NULL;
351
	size_t *wNAF_len = NULL;
352
	size_t max_len = 0;
353
	size_t num_val;
354
	EC_POINT **val = NULL;	/* precomputation */
355
	EC_POINT **v;
356
	EC_POINT ***val_sub = NULL;	/* pointers to sub-arrays of 'val' or
357
					 * 'pre_comp->points' */
358
	const EC_PRE_COMP *pre_comp = NULL;
359
	int num_scalar = 0;	/* flag: will be set to 1 if 'scalar' must be
360
				 * treated like other scalars, i.e.
361
				 * precomputation is not available */
362
	int ret = 0;
363
364
9230
	if (group->meth != r->meth) {
365
		ECerror(EC_R_INCOMPATIBLE_OBJECTS);
366
		return 0;
367
	}
368
4615
	if ((scalar == NULL) && (num == 0)) {
369
		return EC_POINT_set_to_infinity(group, r);
370
	}
371
13960
	for (i = 0; i < num; i++) {
372
2365
		if (group->meth != points[i]->meth) {
373
			ECerror(EC_R_INCOMPATIBLE_OBJECTS);
374
			return 0;
375
		}
376
	}
377
378
4615
	if (ctx == NULL) {
379
90
		ctx = new_ctx = BN_CTX_new();
380
90
		if (ctx == NULL)
381
			goto err;
382
	}
383
4615
	if (scalar != NULL) {
384
2913
		generator = EC_GROUP_get0_generator(group);
385
2913
		if (generator == NULL) {
386
			ECerror(EC_R_UNDEFINED_GENERATOR);
387
			goto err;
388
		}
389
		/* look if we can use precomputed multiples of generator */
390
391
2913
		pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
392
393

3105
		if (pre_comp && pre_comp->numblocks &&
394
96
		    (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0)) {
395
54
			blocksize = pre_comp->blocksize;
396
397
			/*
398
			 * determine maximum number of blocks that wNAF
399
			 * splitting may yield (NB: maximum wNAF length is
400
			 * bit length plus one)
401
			 */
402
54
			numblocks = (BN_num_bits(scalar) / blocksize) + 1;
403
404
			/*
405
			 * we cannot use more blocks than we have
406
			 * precomputation for
407
			 */
408
54
			if (numblocks > pre_comp->numblocks)
409
15
				numblocks = pre_comp->numblocks;
410
411
54
			pre_points_per_block = (size_t) 1 << (pre_comp->w - 1);
412
413
			/* check that pre_comp looks sane */
414
54
			if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block)) {
415
				ECerror(ERR_R_INTERNAL_ERROR);
416
				goto err;
417
			}
418
		} else {
419
			/* can't use precomputation */
420
			pre_comp = NULL;
421
			numblocks = 1;
422
			num_scalar = 1;	/* treat 'scalar' like 'num'-th
423
					 * element of 'scalars' */
424
		}
425
	}
426
4615
	totalnum = num + numblocks;
427
428
	/* includes space for pivot */
429
4615
	wNAF = reallocarray(NULL, (totalnum + 1), sizeof wNAF[0]);
430
4615
	if (wNAF == NULL) {
431
		ECerror(ERR_R_MALLOC_FAILURE);
432
		goto err;
433
	}
434
435
4615
	wNAF[0] = NULL;		/* preliminary pivot */
436
437
4615
	wsize = reallocarray(NULL, totalnum, sizeof wsize[0]);
438
4615
	wNAF_len = reallocarray(NULL, totalnum, sizeof wNAF_len[0]);
439
4615
	val_sub = reallocarray(NULL, totalnum, sizeof val_sub[0]);
440
441
4615
	if (wsize == NULL || wNAF_len == NULL || val_sub == NULL) {
442
		ECerror(ERR_R_MALLOC_FAILURE);
443
		goto err;
444
	}
445
446
	/* num_val will be the total number of temporarily precomputed points */
447
	num_val = 0;
448
449
19678
	for (i = 0; i < num + num_scalar; i++) {
450
		size_t bits;
451
452
15672
		bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
453


25320
		wsize[i] = EC_window_bits_for_scalar_size(bits);
454
5224
		num_val += (size_t) 1 << (wsize[i] - 1);
455
5224
		wNAF[i + 1] = NULL;	/* make sure we always have a pivot */
456
15672
		wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i]);
457
5224
		if (wNAF[i] == NULL)
458
			goto err;
459
5224
		if (wNAF_len[i] > max_len)
460
4844
			max_len = wNAF_len[i];
461
5224
	}
462
463
4615
	if (numblocks) {
464
		/* we go here iff scalar != NULL */
465
466
2913
		if (pre_comp == NULL) {
467
2859
			if (num_scalar != 1) {
468
				ECerror(ERR_R_INTERNAL_ERROR);
469
				goto err;
470
			}
471
			/* we have already generated a wNAF for 'scalar' */
472
		} else {
473
54
			size_t tmp_len = 0;
474
475
54
			if (num_scalar != 0) {
476
				ECerror(ERR_R_INTERNAL_ERROR);
477
				goto err;
478
			}
479
			/*
480
			 * use the window size for which we have
481
			 * precomputation
482
			 */
483
54
			wsize[num] = pre_comp->w;
484
54
			tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len);
485
54
			if (tmp_wNAF == NULL)
486
				goto err;
487
488
54
			if (tmp_len <= max_len) {
489
				/*
490
				 * One of the other wNAFs is at least as long
491
				 * as the wNAF belonging to the generator, so
492
				 * wNAF splitting will not buy us anything.
493
				 */
494
495
				numblocks = 1;
496
				totalnum = num + 1;	/* don't use wNAF
497
							 * splitting */
498
				wNAF[num] = tmp_wNAF;
499
				tmp_wNAF = NULL;
500
				wNAF[num + 1] = NULL;
501
				wNAF_len[num] = tmp_len;
502
				if (tmp_len > max_len)
503
					max_len = tmp_len;
504
				/*
505
				 * pre_comp->points starts with the points
506
				 * that we need here:
507
				 */
508
				val_sub[num] = pre_comp->points;
509
			} else {
510
				/*
511
				 * don't include tmp_wNAF directly into wNAF
512
				 * array - use wNAF splitting and include the
513
				 * blocks
514
				 */
515
516
				signed char *pp;
517
				EC_POINT **tmp_points;
518
519
54
				if (tmp_len < numblocks * blocksize) {
520
					/*
521
					 * possibly we can do with fewer
522
					 * blocks than estimated
523
					 */
524
36
					numblocks = (tmp_len + blocksize - 1) / blocksize;
525
36
					if (numblocks > pre_comp->numblocks) {
526
						ECerror(ERR_R_INTERNAL_ERROR);
527
						goto err;
528
					}
529
36
					totalnum = num + numblocks;
530
36
				}
531
				/* split wNAF in 'numblocks' parts */
532
				pp = tmp_wNAF;
533
54
				tmp_points = pre_comp->points;
534
535
4770
				for (i = num; i < totalnum; i++) {
536
2331
					if (i < totalnum - 1) {
537
2277
						wNAF_len[i] = blocksize;
538
2277
						if (tmp_len < blocksize) {
539
							ECerror(ERR_R_INTERNAL_ERROR);
540
							goto err;
541
						}
542
2277
						tmp_len -= blocksize;
543
2277
					} else
544
						/*
545
						 * last block gets whatever
546
						 * is left (this could be
547
						 * more or less than
548
						 * 'blocksize'!)
549
						 */
550
54
						wNAF_len[i] = tmp_len;
551
552
2331
					wNAF[i + 1] = NULL;
553
2331
					wNAF[i] = malloc(wNAF_len[i]);
554
2331
					if (wNAF[i] == NULL) {
555
						ECerror(ERR_R_MALLOC_FAILURE);
556
						goto err;
557
					}
558
2331
					memcpy(wNAF[i], pp, wNAF_len[i]);
559
2331
					if (wNAF_len[i] > max_len)
560
60
						max_len = wNAF_len[i];
561
562
2331
					if (*tmp_points == NULL) {
563
						ECerror(ERR_R_INTERNAL_ERROR);
564
						goto err;
565
					}
566
2331
					val_sub[i] = tmp_points;
567
2331
					tmp_points += pre_points_per_block;
568
2331
					pp += blocksize;
569
				}
570
54
			}
571
108
		}
572
	}
573
	/*
574
	 * All points we precompute now go into a single array 'val'.
575
	 * 'val_sub[i]' is a pointer to the subarray for the i-th point, or
576
	 * to a subarray of 'pre_comp->points' if we already have
577
	 * precomputation.
578
	 */
579
4615
	val = reallocarray(NULL, (num_val + 1), sizeof val[0]);
580
4615
	if (val == NULL) {
581
		ECerror(ERR_R_MALLOC_FAILURE);
582
		goto err;
583
	}
584
4615
	val[num_val] = NULL;	/* pivot element */
585
586
	/* allocate points for precomputation */
587
	v = val;
588
19678
	for (i = 0; i < num + num_scalar; i++) {
589
5224
		val_sub[i] = v;
590
58670
		for (j = 0; j < ((size_t) 1 << (wsize[i] - 1)); j++) {
591
24111
			*v = EC_POINT_new(group);
592
24111
			if (*v == NULL)
593
				goto err;
594
24111
			v++;
595
		}
596
	}
597
4615
	if (!(v == val + num_val)) {
598
		ECerror(ERR_R_INTERNAL_ERROR);
599
		goto err;
600
	}
601
4615
	if (!(tmp = EC_POINT_new(group)))
602
		goto err;
603
604
	/*
605
	 * prepare precomputed values: val_sub[i][0] :=     points[i]
606
	 * val_sub[i][1] := 3 * points[i] val_sub[i][2] := 5 * points[i] ...
607
	 */
608
19678
	for (i = 0; i < num + num_scalar; i++) {
609
5224
		if (i < num) {
610
2365
			if (!EC_POINT_copy(val_sub[i][0], points[i]))
611
				goto err;
612
		} else {
613
2859
			if (!EC_POINT_copy(val_sub[i][0], generator))
614
				goto err;
615
		}
616
617
5224
		if (wsize[i] > 1) {
618
5221
			if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx))
619
				goto err;
620
48216
			for (j = 1; j < ((size_t) 1 << (wsize[i] - 1)); j++) {
621
18887
				if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx))
622
					goto err;
623
			}
624
		}
625
	}
626
627
4615
	if (!EC_POINTs_make_affine(group, num_val, val, ctx))
628
		goto err;
629
630
	r_is_at_infinity = 1;
631
632
2465850
	for (k = max_len - 1; k >= 0; k--) {
633
1228310
		if (!r_is_at_infinity) {
634
1223695
			if (!EC_POINT_dbl(group, r, r, ctx))
635
				goto err;
636
		}
637
5763146
		for (i = 0; i < totalnum; i++) {
638
1653263
			if (wNAF_len[i] > (size_t) k) {
639
1426948
				int digit = wNAF[i][k];
640
				int is_neg;
641
642
1426948
				if (digit) {
643
266419
					is_neg = digit < 0;
644
645
266419
					if (is_neg)
646
130058
						digit = -digit;
647
648
266419
					if (is_neg != r_is_inverted) {
649
130373
						if (!r_is_at_infinity) {
650
130312
							if (!EC_POINT_invert(group, r, ctx))
651
								goto err;
652
						}
653
130373
						r_is_inverted = !r_is_inverted;
654
130373
					}
655
					/* digit > 0 */
656
657
266419
					if (r_is_at_infinity) {
658
4615
						if (!EC_POINT_copy(r, val_sub[i][digit >> 1]))
659
							goto err;
660
						r_is_at_infinity = 0;
661
4615
					} else {
662
261804
						if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx))
663
							goto err;
664
					}
665
				}
666
1426948
			}
667
		}
668
	}
669
670
4615
	if (r_is_at_infinity) {
671
		if (!EC_POINT_set_to_infinity(group, r))
672
			goto err;
673
	} else {
674
4615
		if (r_is_inverted)
675
2271
			if (!EC_POINT_invert(group, r, ctx))
676
				goto err;
677
	}
678
679
4615
	ret = 1;
680
681
err:
682
4615
	BN_CTX_free(new_ctx);
683
4615
	EC_POINT_free(tmp);
684
4615
	free(wsize);
685
4615
	free(wNAF_len);
686
4615
	free(tmp_wNAF);
687
4615
	if (wNAF != NULL) {
688
		signed char **w;
689
690
24340
		for (w = wNAF; *w != NULL; w++)
691
7555
			free(*w);
692
693
4615
		free(wNAF);
694
4615
	}
695
4615
	if (val != NULL) {
696
57452
		for (v = val; *v != NULL; v++)
697
24111
			EC_POINT_clear_free(*v);
698
4615
		free(val);
699
4615
	}
700
4615
	free(val_sub);
701
4615
	return ret;
702
4615
}
703
704
705
/* ec_wNAF_precompute_mult()
706
 * creates an EC_PRE_COMP object with preprecomputed multiples of the generator
707
 * for use with wNAF splitting as implemented in ec_wNAF_mul().
708
 *
709
 * 'pre_comp->points' is an array of multiples of the generator
710
 * of the following form:
711
 * points[0] =     generator;
712
 * points[1] = 3 * generator;
713
 * ...
714
 * points[2^(w-1)-1] =     (2^(w-1)-1) * generator;
715
 * points[2^(w-1)]   =     2^blocksize * generator;
716
 * points[2^(w-1)+1] = 3 * 2^blocksize * generator;
717
 * ...
718
 * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) *  2^(blocksize*(numblocks-2)) * generator
719
 * points[2^(w-1)*(numblocks-1)]   =              2^(blocksize*(numblocks-1)) * generator
720
 * ...
721
 * points[2^(w-1)*numblocks-1]     = (2^(w-1)) *  2^(blocksize*(numblocks-1)) * generator
722
 * points[2^(w-1)*numblocks]       = NULL
723
 */
724
int
725
ec_wNAF_precompute_mult(EC_GROUP * group, BN_CTX * ctx)
726
{
727
	const EC_POINT *generator;
728
	EC_POINT *tmp_point = NULL, *base = NULL, **var;
729
	BN_CTX *new_ctx = NULL;
730
	BIGNUM *order;
731
	size_t i, bits, w, pre_points_per_block, blocksize, numblocks,
732
	 num;
733
	EC_POINT **points = NULL;
734
	EC_PRE_COMP *pre_comp;
735
	int ret = 0;
736
737
	/* if there is an old EC_PRE_COMP object, throw it away */
738
96
	EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
739
740
48
	if ((pre_comp = ec_pre_comp_new(group)) == NULL)
741
		return 0;
742
743
48
	generator = EC_GROUP_get0_generator(group);
744
48
	if (generator == NULL) {
745
		ECerror(EC_R_UNDEFINED_GENERATOR);
746
		goto err;
747
	}
748
48
	if (ctx == NULL) {
749
		ctx = new_ctx = BN_CTX_new();
750
		if (ctx == NULL)
751
			goto err;
752
	}
753
48
	BN_CTX_start(ctx);
754
48
	if ((order = BN_CTX_get(ctx)) == NULL)
755
		goto err;
756
757
48
	if (!EC_GROUP_get_order(group, order, ctx))
758
		goto err;
759
48
	if (BN_is_zero(order)) {
760
		ECerror(EC_R_UNKNOWN_ORDER);
761
		goto err;
762
	}
763
48
	bits = BN_num_bits(order);
764
	/*
765
	 * The following parameters mean we precompute (approximately) one
766
	 * point per bit.
767
	 *
768
	 * TBD: The combination  8, 4  is perfect for 160 bits; for other bit
769
	 * lengths, other parameter combinations might provide better
770
	 * efficiency.
771
	 */
772
	blocksize = 8;
773
	w = 4;
774


222
	if (EC_window_bits_for_scalar_size(bits) > w) {
775
		/* let's not make the window too small ... */
776
		w = EC_window_bits_for_scalar_size(bits);
777
	}
778
48
	numblocks = (bits + blocksize - 1) / blocksize;	/* max. number of blocks
779
							 * to use for wNAF
780
							 * splitting */
781
782
48
	pre_points_per_block = (size_t) 1 << (w - 1);
783
48
	num = pre_points_per_block * numblocks;	/* number of points to
784
						 * compute and store */
785
786
48
	points = reallocarray(NULL, (num + 1), sizeof(EC_POINT *));
787
48
	if (!points) {
788
		ECerror(ERR_R_MALLOC_FAILURE);
789
		goto err;
790
	}
791
	var = points;
792
48
	var[num] = NULL;	/* pivot */
793
46152
	for (i = 0; i < num; i++) {
794
30720
		if ((var[i] = EC_POINT_new(group)) == NULL) {
795
			ECerror(ERR_R_MALLOC_FAILURE);
796
			goto err;
797
		}
798
	}
799
800

96
	if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group))) {
801
		ECerror(ERR_R_MALLOC_FAILURE);
802
		goto err;
803
	}
804
48
	if (!EC_POINT_copy(base, generator))
805
		goto err;
806
807
	/* do the precomputation */
808
3930
	for (i = 0; i < numblocks; i++) {
809
		size_t j;
810
811
1917
		if (!EC_POINT_dbl(group, tmp_point, base, ctx))
812
			goto err;
813
814
1917
		if (!EC_POINT_copy(*var++, base))
815
			goto err;
816
817
30672
		for (j = 1; j < pre_points_per_block; j++, var++) {
818
			/* calculate odd multiples of the current base point */
819
13419
			if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx))
820
				goto err;
821
		}
822
823
1917
		if (i < numblocks - 1) {
824
			/*
825
			 * get the next base (multiply current one by
826
			 * 2^blocksize)
827
			 */
828
			size_t k;
829
830
1869
			if (blocksize <= 2) {
831
				ECerror(ERR_R_INTERNAL_ERROR);
832
				goto err;
833
			}
834
1869
			if (!EC_POINT_dbl(group, base, tmp_point, ctx))
835
				goto err;
836
26166
			for (k = 2; k < blocksize; k++) {
837
11214
				if (!EC_POINT_dbl(group, base, base, ctx))
838
					goto err;
839
			}
840
1869
		}
841
1917
	}
842
843
48
	if (!EC_POINTs_make_affine(group, num, points, ctx))
844
		goto err;
845
846
48
	pre_comp->group = group;
847
48
	pre_comp->blocksize = blocksize;
848
48
	pre_comp->numblocks = numblocks;
849
48
	pre_comp->w = w;
850
48
	pre_comp->points = points;
851
	points = NULL;
852
48
	pre_comp->num = num;
853
854
48
	if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp,
855
		ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free))
856
		goto err;
857
	pre_comp = NULL;
858
859
48
	ret = 1;
860
err:
861
48
	if (ctx != NULL)
862
48
		BN_CTX_end(ctx);
863
48
	BN_CTX_free(new_ctx);
864
48
	ec_pre_comp_free(pre_comp);
865
48
	if (points) {
866
		EC_POINT **p;
867
868
		for (p = points; *p != NULL; p++)
869
			EC_POINT_free(*p);
870
		free(points);
871
	}
872
48
	EC_POINT_free(tmp_point);
873
48
	EC_POINT_free(base);
874
48
	return ret;
875
48
}
876
877
878
int
879
ec_wNAF_have_precompute_mult(const EC_GROUP * group)
880
{
881
1540
	if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL)
882
57
		return 1;
883
	else
884
713
		return 0;
885
770
}