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Diffstat (limited to 'src/lib/libssl/bs_cbs.c')
-rw-r--r--src/lib/libssl/bs_cbs.c511
1 files changed, 0 insertions, 511 deletions
diff --git a/src/lib/libssl/bs_cbs.c b/src/lib/libssl/bs_cbs.c
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--- a/src/lib/libssl/bs_cbs.c
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1/* $OpenBSD: bs_cbs.c,v 1.17 2015/06/24 09:44:18 jsing Exp $ */
2/*
3 * Copyright (c) 2014, Google Inc.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
12 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
14 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
15 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
16
17#include <assert.h>
18#include <stdlib.h>
19#include <string.h>
20
21#include <openssl/opensslconf.h>
22#include <openssl/buffer.h>
23#include <openssl/crypto.h>
24
25#include "bytestring.h"
26
27void
28CBS_init(CBS *cbs, const uint8_t *data, size_t len)
29{
30 cbs->data = data;
31 cbs->initial_len = len;
32 cbs->len = len;
33}
34
35void
36CBS_dup(const CBS *cbs, CBS *out)
37{
38 CBS_init(out, CBS_data(cbs), CBS_len(cbs));
39 out->initial_len = cbs->initial_len;
40}
41
42static int
43cbs_get(CBS *cbs, const uint8_t **p, size_t n)
44{
45 if (cbs->len < n)
46 return 0;
47
48 *p = cbs->data;
49 cbs->data += n;
50 cbs->len -= n;
51 return 1;
52}
53
54size_t
55CBS_offset(const CBS *cbs)
56{
57 return cbs->initial_len - cbs->len;
58}
59
60int
61CBS_skip(CBS *cbs, size_t len)
62{
63 const uint8_t *dummy;
64 return cbs_get(cbs, &dummy, len);
65}
66
67const uint8_t *
68CBS_data(const CBS *cbs)
69{
70 return cbs->data;
71}
72
73size_t
74CBS_len(const CBS *cbs)
75{
76 return cbs->len;
77}
78
79int
80CBS_stow(const CBS *cbs, uint8_t **out_ptr, size_t *out_len)
81{
82 free(*out_ptr);
83 *out_ptr = NULL;
84 *out_len = 0;
85
86 if (cbs->len == 0)
87 return 1;
88
89 if ((*out_ptr = malloc(cbs->len)) == NULL)
90 return 0;
91
92 memcpy(*out_ptr, cbs->data, cbs->len);
93
94 *out_len = cbs->len;
95 return 1;
96}
97
98int
99CBS_strdup(const CBS *cbs, char **out_ptr)
100{
101 free(*out_ptr);
102 *out_ptr = strndup((const char *)cbs->data, cbs->len);
103 return (*out_ptr != NULL);
104}
105
106int
107CBS_write_bytes(const CBS *cbs, uint8_t *dst, size_t dst_len, size_t *copied)
108{
109 if (dst_len < cbs->len)
110 return 0;
111
112 memmove(dst, cbs->data, cbs->len);
113
114 if (copied != NULL)
115 *copied = cbs->len;
116
117 return 1;
118}
119
120int
121CBS_contains_zero_byte(const CBS *cbs)
122{
123 return memchr(cbs->data, 0, cbs->len) != NULL;
124}
125
126int
127CBS_mem_equal(const CBS *cbs, const uint8_t *data, size_t len)
128{
129 if (len != cbs->len)
130 return 0;
131
132 return timingsafe_memcmp(cbs->data, data, len) == 0;
133}
134
135static int
136cbs_get_u(CBS *cbs, uint32_t *out, size_t len)
137{
138 uint32_t result = 0;
139 size_t i;
140 const uint8_t *data;
141
142 if (len < 1 || len > 4)
143 return 0;
144
145 if (!cbs_get(cbs, &data, len))
146 return 0;
147
148 for (i = 0; i < len; i++) {
149 result <<= 8;
150 result |= data[i];
151 }
152 *out = result;
153 return 1;
154}
155
156int
157CBS_get_u8(CBS *cbs, uint8_t *out)
158{
159 const uint8_t *v;
160
161 if (!cbs_get(cbs, &v, 1))
162 return 0;
163
164 *out = *v;
165 return 1;
166}
167
168int
169CBS_get_u16(CBS *cbs, uint16_t *out)
170{
171 uint32_t v;
172
173 if (!cbs_get_u(cbs, &v, 2))
174 return 0;
175
176 *out = v;
177 return 1;
178}
179
180int
181CBS_get_u24(CBS *cbs, uint32_t *out)
182{
183 return cbs_get_u(cbs, out, 3);
184}
185
186int
187CBS_get_u32(CBS *cbs, uint32_t *out)
188{
189 return cbs_get_u(cbs, out, 4);
190}
191
192int
193CBS_get_bytes(CBS *cbs, CBS *out, size_t len)
194{
195 const uint8_t *v;
196
197 if (!cbs_get(cbs, &v, len))
198 return 0;
199
200 CBS_init(out, v, len);
201 return 1;
202}
203
204static int
205cbs_get_length_prefixed(CBS *cbs, CBS *out, size_t len_len)
206{
207 uint32_t len;
208
209 if (!cbs_get_u(cbs, &len, len_len))
210 return 0;
211
212 return CBS_get_bytes(cbs, out, len);
213}
214
215int
216CBS_get_u8_length_prefixed(CBS *cbs, CBS *out)
217{
218 return cbs_get_length_prefixed(cbs, out, 1);
219}
220
221int
222CBS_get_u16_length_prefixed(CBS *cbs, CBS *out)
223{
224 return cbs_get_length_prefixed(cbs, out, 2);
225}
226
227int
228CBS_get_u24_length_prefixed(CBS *cbs, CBS *out)
229{
230 return cbs_get_length_prefixed(cbs, out, 3);
231}
232
233int
234CBS_get_any_asn1_element(CBS *cbs, CBS *out, unsigned int *out_tag,
235 size_t *out_header_len)
236{
237 return cbs_get_any_asn1_element_internal(cbs, out, out_tag,
238 out_header_len, 1);
239}
240
241/*
242 * Review X.690 for details on ASN.1 DER encoding.
243 *
244 * If non-strict mode is enabled, then DER rules are relaxed
245 * for indefinite constructs (violates DER but a little closer to BER).
246 * Non-strict mode should only be used by bs_ber.c
247 *
248 * Sections 8, 10 and 11 for DER encoding
249 */
250int
251cbs_get_any_asn1_element_internal(CBS *cbs, CBS *out, unsigned int *out_tag,
252 size_t *out_header_len, int strict)
253{
254 uint8_t tag, length_byte;
255 CBS header = *cbs;
256 CBS throwaway;
257 size_t len;
258
259 if (out == NULL)
260 out = &throwaway;
261
262 /*
263 * Get identifier octet and length octet. Only 1 octet for each
264 * is a CBS limitation.
265 */
266 if (!CBS_get_u8(&header, &tag) || !CBS_get_u8(&header, &length_byte))
267 return 0;
268
269 /* CBS limitation: long form tags are not supported. */
270 if ((tag & 0x1f) == 0x1f)
271 return 0;
272
273 if (out_tag != NULL)
274 *out_tag = tag;
275
276 if ((length_byte & 0x80) == 0) {
277 /* Short form length. */
278 len = ((size_t) length_byte) + 2;
279 if (out_header_len != NULL)
280 *out_header_len = 2;
281
282 } else {
283 /* Long form length. */
284 const size_t num_bytes = length_byte & 0x7f;
285 uint32_t len32;
286
287 /* ASN.1 reserved value for future extensions */
288 if (num_bytes == 0x7f)
289 return 0;
290
291 /* Handle indefinite form length */
292 if (num_bytes == 0) {
293 /* DER encoding doesn't allow for indefinite form. */
294 if (strict)
295 return 0;
296
297 /* Primitive cannot use indefinite in BER or DER. */
298 if ((tag & CBS_ASN1_CONSTRUCTED) == 0)
299 return 0;
300
301 /* Constructed, indefinite length allowed in BER. */
302 if (out_header_len != NULL)
303 *out_header_len = 2;
304 return CBS_get_bytes(cbs, out, 2);
305 }
306
307 /* CBS limitation. */
308 if (num_bytes > 4)
309 return 0;
310
311 if (!cbs_get_u(&header, &len32, num_bytes))
312 return 0;
313
314 /* DER has a minimum length octet requirement. */
315 if (len32 < 128)
316 /* Should have used short form instead */
317 return 0;
318
319 if ((len32 >> ((num_bytes - 1) * 8)) == 0)
320 /* Length should have been at least one byte shorter. */
321 return 0;
322
323 len = len32;
324 if (len + 2 + num_bytes < len)
325 /* Overflow. */
326 return 0;
327
328 len += 2 + num_bytes;
329 if (out_header_len != NULL)
330 *out_header_len = 2 + num_bytes;
331 }
332
333 return CBS_get_bytes(cbs, out, len);
334}
335
336static int
337cbs_get_asn1(CBS *cbs, CBS *out, unsigned int tag_value, int skip_header)
338{
339 size_t header_len;
340 unsigned int tag;
341 CBS throwaway;
342
343 if (out == NULL)
344 out = &throwaway;
345
346 if (!CBS_get_any_asn1_element(cbs, out, &tag, &header_len) ||
347 tag != tag_value)
348 return 0;
349
350 if (skip_header && !CBS_skip(out, header_len)) {
351 assert(0);
352 return 0;
353 }
354
355 return 1;
356}
357
358int
359CBS_get_asn1(CBS *cbs, CBS *out, unsigned int tag_value)
360{
361 return cbs_get_asn1(cbs, out, tag_value, 1 /* skip header */);
362}
363
364int
365CBS_get_asn1_element(CBS *cbs, CBS *out, unsigned int tag_value)
366{
367 return cbs_get_asn1(cbs, out, tag_value, 0 /* include header */);
368}
369
370int
371CBS_peek_asn1_tag(const CBS *cbs, unsigned int tag_value)
372{
373 if (CBS_len(cbs) < 1)
374 return 0;
375
376 /*
377 * Tag number 31 indicates the start of a long form number.
378 * This is valid in ASN.1, but CBS only supports short form.
379 */
380 if ((tag_value & 0x1f) == 0x1f)
381 return 0;
382
383 return CBS_data(cbs)[0] == tag_value;
384}
385
386/* Encoding details are in ASN.1: X.690 section 8.3 */
387int
388CBS_get_asn1_uint64(CBS *cbs, uint64_t *out)
389{
390 CBS bytes;
391 const uint8_t *data;
392 size_t i, len;
393
394 if (!CBS_get_asn1(cbs, &bytes, CBS_ASN1_INTEGER))
395 return 0;
396
397 *out = 0;
398 data = CBS_data(&bytes);
399 len = CBS_len(&bytes);
400
401 if (len == 0)
402 /* An INTEGER is encoded with at least one content octet. */
403 return 0;
404
405 if ((data[0] & 0x80) != 0)
406 /* Negative number. */
407 return 0;
408
409 if (data[0] == 0 && len > 1 && (data[1] & 0x80) == 0)
410 /* Violates smallest encoding rule: excessive leading zeros. */
411 return 0;
412
413 for (i = 0; i < len; i++) {
414 if ((*out >> 56) != 0)
415 /* Too large to represent as a uint64_t. */
416 return 0;
417
418 *out <<= 8;
419 *out |= data[i];
420 }
421
422 return 1;
423}
424
425int
426CBS_get_optional_asn1(CBS *cbs, CBS *out, int *out_present, unsigned int tag)
427{
428 if (CBS_peek_asn1_tag(cbs, tag)) {
429 if (!CBS_get_asn1(cbs, out, tag))
430 return 0;
431
432 *out_present = 1;
433 } else {
434 *out_present = 0;
435 }
436 return 1;
437}
438
439int
440CBS_get_optional_asn1_octet_string(CBS *cbs, CBS *out, int *out_present,
441 unsigned int tag)
442{
443 CBS child;
444 int present;
445
446 if (!CBS_get_optional_asn1(cbs, &child, &present, tag))
447 return 0;
448
449 if (present) {
450 if (!CBS_get_asn1(&child, out, CBS_ASN1_OCTETSTRING) ||
451 CBS_len(&child) != 0)
452 return 0;
453 } else {
454 CBS_init(out, NULL, 0);
455 }
456 if (out_present)
457 *out_present = present;
458
459 return 1;
460}
461
462int
463CBS_get_optional_asn1_uint64(CBS *cbs, uint64_t *out, unsigned int tag,
464 uint64_t default_value)
465{
466 CBS child;
467 int present;
468
469 if (!CBS_get_optional_asn1(cbs, &child, &present, tag))
470 return 0;
471
472 if (present) {
473 if (!CBS_get_asn1_uint64(&child, out) ||
474 CBS_len(&child) != 0)
475 return 0;
476 } else {
477 *out = default_value;
478 }
479 return 1;
480}
481
482int
483CBS_get_optional_asn1_bool(CBS *cbs, int *out, unsigned int tag,
484 int default_value)
485{
486 CBS child, child2;
487 int present;
488
489 if (!CBS_get_optional_asn1(cbs, &child, &present, tag))
490 return 0;
491
492 if (present) {
493 uint8_t boolean;
494
495 if (!CBS_get_asn1(&child, &child2, CBS_ASN1_BOOLEAN) ||
496 CBS_len(&child2) != 1 || CBS_len(&child) != 0)
497 return 0;
498
499 boolean = CBS_data(&child2)[0];
500 if (boolean == 0)
501 *out = 0;
502 else if (boolean == 0xff)
503 *out = 1;
504 else
505 return 0;
506
507 } else {
508 *out = default_value;
509 }
510 return 1;
511}
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