GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcrypto/asn1/a_int.c Lines: 97 195 49.7 %
Date: 2017-11-07 Branches: 52 129 40.3 %

Line Branch Exec Source
1
/* $OpenBSD: a_int.c,v 1.31 2017/01/29 17:49:22 beck Exp $ */
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
#include <stdio.h>
60
#include <string.h>
61
62
#include <openssl/asn1.h>
63
#include <openssl/bn.h>
64
#include <openssl/err.h>
65
66
ASN1_INTEGER *
67
ASN1_INTEGER_dup(const ASN1_INTEGER *x)
68
{
69
60
	return ASN1_STRING_dup(x);
70
}
71
72
int
73
ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
74
{
75
	int neg, ret;
76
77
	/* Compare signs */
78
12
	neg = x->type & V_ASN1_NEG;
79
6
	if (neg != (y->type & V_ASN1_NEG)) {
80
		if (neg)
81
			return -1;
82
		else
83
			return 1;
84
	}
85
86
6
	ret = ASN1_STRING_cmp(x, y);
87
88
6
	if (neg)
89
		return -ret;
90
	else
91
6
		return ret;
92
6
}
93
94
95
/*
96
 * This converts an ASN1 INTEGER into its content encoding.
97
 * The internal representation is an ASN1_STRING whose data is a big endian
98
 * representation of the value, ignoring the sign. The sign is determined by
99
 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
100
 *
101
 * Positive integers are no problem: they are almost the same as the DER
102
 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
103
 *
104
 * Negative integers are a bit trickier...
105
 * The DER representation of negative integers is in 2s complement form.
106
 * The internal form is converted by complementing each octet and finally
107
 * adding one to the result. This can be done less messily with a little trick.
108
 * If the internal form has trailing zeroes then they will become FF by the
109
 * complement and 0 by the add one (due to carry) so just copy as many trailing
110
 * zeros to the destination as there are in the source. The carry will add one
111
 * to the last none zero octet: so complement this octet and add one and finally
112
 * complement any left over until you get to the start of the string.
113
 *
114
 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
115
 * with 0xff. However if the first byte is 0x80 and one of the following bytes
116
 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
117
 * followed by optional zeros isn't padded.
118
 */
119
120
int
121
i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
122
{
123
	int pad = 0, ret, i, neg;
124
	unsigned char *p, *n, pb = 0;
125
126
23128
	if (a == NULL)
127
		return (0);
128
11564
	neg = a->type & V_ASN1_NEG;
129
11564
	if (a->length == 0)
130
814
		ret = 1;
131
	else {
132
		ret = a->length;
133
10750
		i = a->data[0];
134
10750
		if (!neg && (i > 127)) {
135
			pad = 1;
136
			pb = 0;
137
10750
		} else if (neg) {
138
			if (i > 128) {
139
				pad = 1;
140
				pb = 0xFF;
141
			} else if (i == 128) {
142
				/*
143
				 * Special case: if any other bytes non zero we pad:
144
				 * otherwise we don't.
145
				 */
146
				for (i = 1; i < a->length; i++) if (a->data[i]) {
147
					pad = 1;
148
					pb = 0xFF;
149
					break;
150
				}
151
			}
152
		}
153
10750
		ret += pad;
154
	}
155
11564
	if (pp == NULL)
156
9558
		return (ret);
157
2006
	p= *pp;
158
159
2006
	if (pad)
160
661
		*(p++) = pb;
161
2006
	if (a->length == 0)
162
188
		*(p++) = 0;
163
1818
	else if (!neg)
164
1818
		memcpy(p, a->data, a->length);
165
	else {
166
		/* Begin at the end of the encoding */
167
		n = a->data + a->length - 1;
168
		p += a->length - 1;
169
		i = a->length;
170
		/* Copy zeros to destination as long as source is zero */
171
		while (!*n) {
172
			*(p--) = 0;
173
			n--;
174
			i--;
175
		}
176
		/* Complement and increment next octet */
177
		*(p--) = ((*(n--)) ^ 0xff) + 1;
178
		i--;
179
		/* Complement any octets left */
180
		for (; i > 0; i--)
181
			*(p--) = *(n--) ^ 0xff;
182
	}
183
184
2006
	*pp += ret;
185
2006
	return (ret);
186
11564
}
187
188
/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
189
190
ASN1_INTEGER *
191
c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp, long len)
192
{
193
	ASN1_INTEGER *ret = NULL;
194
	const unsigned char *p, *pend;
195
	unsigned char *to, *s;
196
	int i;
197
198

88878
	if ((a == NULL) || ((*a) == NULL)) {
199
13596
		if ((ret = ASN1_INTEGER_new()) == NULL)
200
			return (NULL);
201
	} else
202
		ret = (*a);
203
204
29626
	p = *pp;
205
29626
	pend = p + len;
206
207
	/* We must malloc stuff, even for 0 bytes otherwise it
208
	 * signifies a missing NULL parameter. */
209
29626
	s = malloc(len + 1);
210
29626
	if (s == NULL) {
211
		i = ERR_R_MALLOC_FAILURE;
212
		goto err;
213
	}
214
	to = s;
215
29626
	if (!len) {
216
		/* Strictly speaking this is an illegal INTEGER but we
217
		 * tolerate it.
218
		 */
219
		ret->type = V_ASN1_INTEGER;
220
29626
	} else if (*p & 0x80) /* a negative number */ {
221
		ret->type = V_ASN1_NEG_INTEGER;
222
		if ((*p == 0xff) && (len != 1)) {
223
			p++;
224
			len--;
225
		}
226
		i = len;
227
		p += i - 1;
228
		to += i - 1;
229
		while((!*p) && i) {
230
			*(to--) = 0;
231
			i--;
232
			p--;
233
		}
234
		/* Special case: if all zeros then the number will be of
235
		 * the form FF followed by n zero bytes: this corresponds to
236
		 * 1 followed by n zero bytes. We've already written n zeros
237
		 * so we just append an extra one and set the first byte to
238
		 * a 1. This is treated separately because it is the only case
239
		 * where the number of bytes is larger than len.
240
		 */
241
		if (!i) {
242
			*s = 1;
243
			s[len] = 0;
244
			len++;
245
		} else {
246
			*(to--) = (*(p--) ^ 0xff) + 1;
247
			i--;
248
			for (; i > 0; i--)
249
				*(to--) = *(p--) ^ 0xff;
250
		}
251
	} else {
252
29626
		ret->type = V_ASN1_INTEGER;
253
29626
		if ((*p == 0) && (len != 1)) {
254
3056
			p++;
255
3056
			len--;
256
3056
		}
257
29626
		memcpy(s, p, len);
258
	}
259
260
29626
	free(ret->data);
261
29626
	ret->data = s;
262
29626
	ret->length = (int)len;
263
29626
	if (a != NULL)
264
29626
		(*a) = ret;
265
29626
	*pp = pend;
266
29626
	return (ret);
267
268
err:
269
	ASN1error(i);
270
	if (a == NULL || *a != ret)
271
		ASN1_INTEGER_free(ret);
272
	return (NULL);
273
29626
}
274
275
276
/* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of
277
 * ASN1 integers: some broken software can encode a positive INTEGER
278
 * with its MSB set as negative (it doesn't add a padding zero).
279
 */
280
281
ASN1_INTEGER *
282
d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp, long length)
283
{
284
	ASN1_INTEGER *ret = NULL;
285
	const unsigned char *p;
286
	unsigned char *s;
287
	long len;
288
	int inf, tag, xclass;
289
	int i;
290
291
	if ((a == NULL) || ((*a) == NULL)) {
292
		if ((ret = ASN1_INTEGER_new()) == NULL)
293
			return (NULL);
294
	} else
295
		ret = (*a);
296
297
	p = *pp;
298
	inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
299
	if (inf & 0x80) {
300
		i = ASN1_R_BAD_OBJECT_HEADER;
301
		goto err;
302
	}
303
304
	if (tag != V_ASN1_INTEGER) {
305
		i = ASN1_R_EXPECTING_AN_INTEGER;
306
		goto err;
307
	}
308
309
	/* We must malloc stuff, even for 0 bytes otherwise it
310
	 * signifies a missing NULL parameter. */
311
	s = malloc(len + 1);
312
	if (s == NULL) {
313
		i = ERR_R_MALLOC_FAILURE;
314
		goto err;
315
	}
316
	ret->type = V_ASN1_INTEGER;
317
	if (len) {
318
		if ((*p == 0) && (len != 1)) {
319
			p++;
320
			len--;
321
		}
322
		memcpy(s, p, len);
323
		p += len;
324
	}
325
326
	free(ret->data);
327
	ret->data = s;
328
	ret->length = (int)len;
329
	if (a != NULL)
330
		(*a) = ret;
331
	*pp = p;
332
	return (ret);
333
334
err:
335
	ASN1error(i);
336
	if (a == NULL || *a != ret)
337
		ASN1_INTEGER_free(ret);
338
	return (NULL);
339
}
340
341
int
342
ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
343
{
344
	int j, k;
345
	unsigned int i;
346
1140
	unsigned char buf[sizeof(long) + 1];
347
	long d;
348
349
570
	a->type = V_ASN1_INTEGER;
350
	/* XXX ssl/ssl_asn1.c:i2d_SSL_SESSION() depends upon this bound vae */
351
570
	if (a->length < (int)(sizeof(long) + 1)) {
352
570
		free(a->data);
353
570
		a->data = calloc(1, sizeof(long) + 1);
354
570
	}
355
570
	if (a->data == NULL) {
356
		ASN1error(ERR_R_MALLOC_FAILURE);
357
		return (0);
358
	}
359
	d = v;
360
570
	if (d < 0) {
361
		d = -d;
362
		a->type = V_ASN1_NEG_INTEGER;
363
	}
364
365
2928
	for (i = 0; i < sizeof(long); i++) {
366
976
		if (d == 0)
367
			break;
368
406
		buf[i] = (int)d & 0xff;
369
406
		d >>= 8;
370
	}
371
	j = 0;
372
1952
	for (k = i - 1; k >= 0; k--)
373
406
		a->data[j++] = buf[k];
374
570
	a->length = j;
375
570
	return (1);
376
570
}
377
378
long
379
ASN1_INTEGER_get(const ASN1_INTEGER *a)
380
{
381
	int neg = 0, i;
382
	long r = 0;
383
384
5564
	if (a == NULL)
385
1806
		return (0L);
386
976
	i = a->type;
387
976
	if (i == V_ASN1_NEG_INTEGER)
388
		neg = 1;
389
976
	else if (i != V_ASN1_INTEGER)
390
		return -1;
391
392
976
	if (a->length > (int)sizeof(long)) {
393
		/* hmm... a bit ugly, return all ones */
394
		return -1;
395
	}
396
976
	if (a->data == NULL)
397
		return 0;
398
399
4160
	for (i = 0; i < a->length; i++) {
400
1104
		r <<= 8;
401
1104
		r |= (unsigned char)a->data[i];
402
	}
403
976
	if (neg)
404
		r = -r;
405
976
	return (r);
406
2782
}
407
408
ASN1_INTEGER *
409
BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
410
{
411
	ASN1_INTEGER *ret;
412
	int len, j;
413
414
5708
	if (ai == NULL)
415
1716
		ret = ASN1_INTEGER_new();
416
	else
417
		ret = ai;
418
2854
	if (ret == NULL) {
419
		ASN1error(ERR_R_NESTED_ASN1_ERROR);
420
		goto err;
421
	}
422
2854
	if (BN_is_negative(bn))
423
		ret->type = V_ASN1_NEG_INTEGER;
424
	else
425
		ret->type = V_ASN1_INTEGER;
426
2854
	j = BN_num_bits(bn);
427
8562
	len = ((j == 0) ? 0 : ((j / 8) + 1));
428
2854
	if (ret->length < len + 4) {
429
2854
		unsigned char *new_data = realloc(ret->data, len + 4);
430
2854
		if (!new_data) {
431
			ASN1error(ERR_R_MALLOC_FAILURE);
432
			goto err;
433
		}
434
2854
		ret->data = new_data;
435
2854
	}
436
2854
	ret->length = BN_bn2bin(bn, ret->data);
437
438
	/* Correct zero case */
439
2854
	if (!ret->length) {
440
		ret->data[0] = 0;
441
		ret->length = 1;
442
	}
443
2854
	return (ret);
444
445
err:
446
	if (ret != ai)
447
		ASN1_INTEGER_free(ret);
448
	return (NULL);
449
2854
}
450
451
BIGNUM *
452
ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
453
{
454
	BIGNUM *ret;
455
456
1024
	if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL)
457
		ASN1error(ASN1_R_BN_LIB);
458
512
	else if (ai->type == V_ASN1_NEG_INTEGER)
459
		BN_set_negative(ret, 1);
460
512
	return (ret);
461
}