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a2bb2735 | 1 | /* |
2 | * libopenemv - a library to work with EMV family of smart cards | |
3 | * Copyright (C) 2012, 2015 Dmitry Eremin-Solenikov | |
4 | * | |
5 | * This library is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU Lesser General Public | |
7 | * License as published by the Free Software Foundation; either | |
8 | * version 2.1 of the License, or (at your option) any later version. | |
9 | * | |
10 | * This library is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * Lesser General Public License for more details. | |
14 | * | |
15 | * https://github.com/lumag/emv-tools/blob/master/lib/tlv.c | |
16 | */ | |
17 | ||
18 | #ifdef HAVE_CONFIG_H | |
19 | #include <config.h> | |
20 | #endif | |
21 | ||
22 | #include "tlv.h" | |
23 | ||
24 | #include <string.h> | |
25 | #include <stdint.h> | |
26 | #include <stddef.h> | |
27 | #include <stdlib.h> | |
28 | ||
29 | #define TLV_TAG_CLASS_MASK 0xc0 | |
30 | #define TLV_TAG_COMPLEX 0x20 | |
31 | #define TLV_TAG_VALUE_MASK 0x1f | |
32 | #define TLV_TAG_VALUE_CONT 0x1f | |
33 | #define TLV_TAG_INVALID 0 | |
34 | ||
35 | #define TLV_LEN_LONG 0x80 | |
36 | #define TLV_LEN_MASK 0x7f | |
37 | #define TLV_LEN_INVALID (~0) | |
38 | ||
39 | // http://radek.io/2012/11/10/magical-container_of-macro/ | |
40 | //#define container_of(ptr, type, member) ({ | |
41 | // const typeof( ((type *)0)->member ) *__mptr = (ptr); | |
42 | // (type *)( (char *)__mptr - offsetof(type,member) );}) | |
43 | ||
44 | struct tlvdb { | |
45 | struct tlv tag; | |
46 | struct tlvdb *next; | |
47 | struct tlvdb *parent; | |
48 | struct tlvdb *children; | |
49 | }; | |
50 | ||
51 | struct tlvdb_root { | |
52 | struct tlvdb db; | |
53 | size_t len; | |
54 | unsigned char buf[0]; | |
55 | }; | |
56 | ||
57 | static tlv_tag_t tlv_parse_tag(const unsigned char **buf, size_t *len) | |
58 | { | |
59 | tlv_tag_t tag; | |
60 | ||
61 | if (*len == 0) | |
62 | return TLV_TAG_INVALID; | |
63 | tag = **buf; | |
64 | --*len; | |
65 | ++*buf; | |
66 | if ((tag & TLV_TAG_VALUE_MASK) != TLV_TAG_VALUE_CONT) | |
67 | return tag; | |
68 | ||
69 | if (*len == 0) | |
70 | return TLV_TAG_INVALID; | |
71 | ||
72 | tag <<= 8; | |
73 | tag |= **buf; | |
74 | --*len; | |
75 | ++*buf; | |
76 | ||
77 | return tag; | |
78 | } | |
79 | ||
80 | static size_t tlv_parse_len(const unsigned char **buf, size_t *len) | |
81 | { | |
82 | size_t l; | |
83 | ||
84 | if (*len == 0) | |
85 | return TLV_LEN_INVALID; | |
86 | ||
87 | l = **buf; | |
88 | --*len; | |
89 | ++*buf; | |
90 | ||
91 | if (!(l & TLV_LEN_LONG)) | |
92 | return l; | |
93 | ||
94 | size_t ll = l &~ TLV_LEN_LONG; | |
14290308 | 95 | if (ll > 5) |
a2bb2735 | 96 | return TLV_LEN_INVALID; |
97 | ||
14290308 OM |
98 | l = 0; |
99 | for (int i = 1; i <= ll; i++) { | |
100 | l = (l << 8) + **buf; | |
101 | --*len; | |
102 | ++*buf; | |
103 | } | |
a2bb2735 | 104 | |
105 | return l; | |
106 | } | |
107 | ||
108 | bool tlv_parse_tl(const unsigned char **buf, size_t *len, struct tlv *tlv) | |
109 | { | |
110 | tlv->value = 0; | |
111 | ||
112 | tlv->tag = tlv_parse_tag(buf, len); | |
113 | if (tlv->tag == TLV_TAG_INVALID) | |
114 | return false; | |
115 | ||
116 | tlv->len = tlv_parse_len(buf, len); | |
117 | if (tlv->len == TLV_LEN_INVALID) | |
118 | return false; | |
119 | ||
120 | return true; | |
121 | } | |
122 | ||
123 | static struct tlvdb *tlvdb_parse_children(struct tlvdb *parent); | |
124 | ||
125 | static bool tlvdb_parse_one(struct tlvdb *tlvdb, | |
126 | struct tlvdb *parent, | |
127 | const unsigned char **tmp, | |
128 | size_t *left) | |
129 | { | |
130 | tlvdb->next = tlvdb->children = NULL; | |
131 | tlvdb->parent = parent; | |
132 | ||
133 | tlvdb->tag.tag = tlv_parse_tag(tmp, left); | |
134 | if (tlvdb->tag.tag == TLV_TAG_INVALID) | |
135 | goto err; | |
136 | ||
137 | tlvdb->tag.len = tlv_parse_len(tmp, left); | |
138 | if (tlvdb->tag.len == TLV_LEN_INVALID) | |
139 | goto err; | |
140 | ||
141 | if (tlvdb->tag.len > *left) | |
142 | goto err; | |
143 | ||
144 | tlvdb->tag.value = *tmp; | |
145 | ||
146 | *tmp += tlvdb->tag.len; | |
147 | *left -= tlvdb->tag.len; | |
148 | ||
149 | if (tlv_is_constructed(&tlvdb->tag) && (tlvdb->tag.len != 0)) { | |
150 | tlvdb->children = tlvdb_parse_children(tlvdb); | |
151 | if (!tlvdb->children) | |
152 | goto err; | |
153 | } else { | |
154 | tlvdb->children = NULL; | |
155 | } | |
156 | ||
157 | return true; | |
158 | ||
159 | err: | |
160 | return false; | |
161 | } | |
162 | ||
163 | static struct tlvdb *tlvdb_parse_children(struct tlvdb *parent) | |
164 | { | |
165 | const unsigned char *tmp = parent->tag.value; | |
166 | size_t left = parent->tag.len; | |
167 | struct tlvdb *tlvdb, *first = NULL, *prev = NULL; | |
168 | ||
169 | while (left != 0) { | |
170 | tlvdb = malloc(sizeof(*tlvdb)); | |
171 | if (prev) | |
172 | prev->next = tlvdb; | |
173 | else | |
174 | first = tlvdb; | |
175 | prev = tlvdb; | |
176 | ||
177 | if (!tlvdb_parse_one(tlvdb, parent, &tmp, &left)) | |
178 | goto err; | |
179 | ||
180 | tlvdb->parent = parent; | |
181 | } | |
182 | ||
183 | return first; | |
184 | ||
185 | err: | |
186 | tlvdb_free(first); | |
187 | ||
188 | return NULL; | |
189 | } | |
190 | ||
191 | struct tlvdb *tlvdb_parse(const unsigned char *buf, size_t len) | |
192 | { | |
193 | struct tlvdb_root *root; | |
194 | const unsigned char *tmp; | |
195 | size_t left; | |
196 | ||
197 | if (!len || !buf) | |
198 | return NULL; | |
199 | ||
200 | root = malloc(sizeof(*root) + len); | |
201 | root->len = len; | |
202 | memcpy(root->buf, buf, len); | |
203 | ||
204 | tmp = root->buf; | |
205 | left = len; | |
206 | ||
207 | if (!tlvdb_parse_one(&root->db, NULL, &tmp, &left)) | |
208 | goto err; | |
209 | ||
210 | if (left) | |
211 | goto err; | |
212 | ||
213 | return &root->db; | |
214 | ||
215 | err: | |
216 | tlvdb_free(&root->db); | |
217 | ||
218 | return NULL; | |
219 | } | |
220 | ||
221 | struct tlvdb *tlvdb_parse_multi(const unsigned char *buf, size_t len) | |
222 | { | |
223 | struct tlvdb_root *root; | |
224 | const unsigned char *tmp; | |
225 | size_t left; | |
226 | ||
227 | if (!len || !buf) | |
228 | return NULL; | |
229 | ||
230 | root = malloc(sizeof(*root) + len); | |
231 | root->len = len; | |
232 | memcpy(root->buf, buf, len); | |
233 | ||
234 | tmp = root->buf; | |
235 | left = len; | |
236 | ||
237 | if (!tlvdb_parse_one(&root->db, NULL, &tmp, &left)) | |
238 | goto err; | |
239 | ||
240 | while (left != 0) { | |
241 | struct tlvdb *db = malloc(sizeof(*db)); | |
242 | if (!tlvdb_parse_one(db, NULL, &tmp, &left)) { | |
243 | free (db); | |
244 | goto err; | |
245 | } | |
246 | ||
247 | tlvdb_add(&root->db, db); | |
248 | } | |
249 | ||
250 | return &root->db; | |
251 | ||
252 | err: | |
253 | tlvdb_free(&root->db); | |
254 | ||
255 | return NULL; | |
256 | } | |
257 | ||
258 | struct tlvdb *tlvdb_fixed(tlv_tag_t tag, size_t len, const unsigned char *value) | |
259 | { | |
260 | struct tlvdb_root *root = malloc(sizeof(*root) + len); | |
261 | ||
262 | root->len = len; | |
263 | memcpy(root->buf, value, len); | |
264 | ||
265 | root->db.parent = root->db.next = root->db.children = NULL; | |
266 | root->db.tag.tag = tag; | |
267 | root->db.tag.len = len; | |
268 | root->db.tag.value = root->buf; | |
269 | ||
270 | return &root->db; | |
271 | } | |
272 | ||
273 | struct tlvdb *tlvdb_external(tlv_tag_t tag, size_t len, const unsigned char *value) | |
274 | { | |
275 | struct tlvdb_root *root = malloc(sizeof(*root)); | |
276 | ||
277 | root->len = 0; | |
278 | ||
279 | root->db.parent = root->db.next = root->db.children = NULL; | |
280 | root->db.tag.tag = tag; | |
281 | root->db.tag.len = len; | |
282 | root->db.tag.value = value; | |
283 | ||
284 | return &root->db; | |
285 | } | |
286 | ||
287 | void tlvdb_free(struct tlvdb *tlvdb) | |
288 | { | |
289 | struct tlvdb *next = NULL; | |
290 | ||
291 | if (!tlvdb) | |
292 | return; | |
293 | ||
294 | for (; tlvdb; tlvdb = next) { | |
295 | next = tlvdb->next; | |
296 | tlvdb_free(tlvdb->children); | |
297 | free(tlvdb); | |
298 | } | |
299 | } | |
300 | ||
3c5fce2b OM |
301 | struct tlvdb *tlvdb_find_next(struct tlvdb *tlvdb, tlv_tag_t tag) { |
302 | if (!tlvdb) | |
303 | return NULL; | |
304 | ||
305 | return tlvdb_find(tlvdb->next, tag); | |
306 | } | |
307 | ||
308 | struct tlvdb *tlvdb_find(struct tlvdb *tlvdb, tlv_tag_t tag) { | |
309 | if (!tlvdb) | |
310 | return NULL; | |
311 | ||
312 | for (; tlvdb; tlvdb = tlvdb->next) { | |
313 | if (tlvdb->tag.tag == tag) | |
314 | return tlvdb; | |
315 | } | |
316 | ||
317 | return NULL; | |
318 | } | |
319 | ||
556826b5 OM |
320 | struct tlvdb *tlvdb_find_full(struct tlvdb *tlvdb, tlv_tag_t tag) { |
321 | if (!tlvdb) | |
322 | return NULL; | |
323 | ||
324 | for (; tlvdb; tlvdb = tlvdb->next) { | |
325 | if (tlvdb->tag.tag == tag) | |
326 | return tlvdb; | |
327 | ||
328 | if (tlvdb->children) { | |
329 | struct tlvdb * ch = tlvdb_find_full(tlvdb->children, tag); | |
330 | if (ch) | |
331 | return ch; | |
332 | } | |
333 | } | |
334 | ||
335 | return NULL; | |
336 | } | |
337 | ||
3c5fce2b OM |
338 | struct tlvdb *tlvdb_find_path(struct tlvdb *tlvdb, tlv_tag_t tag[]) { |
339 | int i = 0; | |
340 | struct tlvdb *tnext = tlvdb; | |
341 | ||
342 | while (tnext && tag[i]) { | |
343 | tnext = tlvdb_find(tnext, tag[i]); | |
344 | i++; | |
345 | if (tag[i] && tnext) { | |
346 | tnext = tnext->children; | |
347 | } | |
348 | } | |
349 | ||
350 | return tnext; | |
351 | } | |
352 | ||
a2bb2735 | 353 | void tlvdb_add(struct tlvdb *tlvdb, struct tlvdb *other) |
354 | { | |
355 | while (tlvdb->next) { | |
356 | tlvdb = tlvdb->next; | |
357 | } | |
358 | ||
359 | tlvdb->next = other; | |
360 | } | |
361 | ||
556826b5 OM |
362 | void tlvdb_change_or_add_node(struct tlvdb *tlvdb, tlv_tag_t tag, size_t len, const unsigned char *value) |
363 | { | |
364 | struct tlvdb *telm = tlvdb_find_full(tlvdb, tag); | |
365 | if (telm == NULL) { | |
366 | // new tlv element | |
367 | tlvdb_add(tlvdb, tlvdb_fixed(tag, len, value)); | |
368 | } else { | |
369 | // the same tlv structure | |
370 | if (telm->tag.tag == tag && telm->tag.len == len && !memcmp(telm->tag.value, value, len)) | |
371 | return; | |
372 | ||
373 | // replace tlv element | |
374 | struct tlvdb *tnewelm = tlvdb_fixed(tag, len, value); | |
375 | tnewelm->next = telm->next; | |
376 | tnewelm->parent = telm->parent; | |
377 | ||
378 | // if telm stayed first in children chain | |
379 | if (telm->parent && telm->parent->children == telm) { | |
380 | telm->parent->children = tnewelm; | |
381 | } | |
382 | ||
383 | // if telm have previous element | |
384 | if (telm != tlvdb) { | |
385 | // elm in root | |
386 | struct tlvdb *celm = tlvdb; | |
387 | // elm in child list of node | |
388 | if (telm->parent && telm->parent->children) | |
389 | celm = telm->parent->children; | |
390 | ||
391 | // find previous element | |
392 | for (; celm; celm = celm->next) { | |
393 | if (celm->next == telm) { | |
394 | celm->next = tnewelm; | |
395 | break; | |
396 | } | |
397 | } | |
398 | } | |
399 | ||
400 | // free old element with childrens | |
401 | telm->next = NULL; | |
402 | tlvdb_free(telm); | |
403 | } | |
404 | ||
405 | return; | |
406 | } | |
407 | ||
43912d63 | 408 | void tlvdb_visit(const struct tlvdb *tlvdb, tlv_cb cb, void *data, int level) |
a2bb2735 | 409 | { |
410 | struct tlvdb *next = NULL; | |
411 | ||
412 | if (!tlvdb) | |
413 | return; | |
414 | ||
415 | for (; tlvdb; tlvdb = next) { | |
416 | next = tlvdb->next; | |
3c5fce2b OM |
417 | cb(data, &tlvdb->tag, level, (tlvdb->children == NULL)); |
418 | tlvdb_visit(tlvdb->children, cb, data, level + 1); | |
a2bb2735 | 419 | } |
420 | } | |
421 | ||
422 | static const struct tlvdb *tlvdb_next(const struct tlvdb *tlvdb) | |
423 | { | |
424 | if (tlvdb->children) | |
425 | return tlvdb->children; | |
426 | ||
427 | while (tlvdb) { | |
428 | if (tlvdb->next) | |
429 | return tlvdb->next; | |
430 | ||
431 | tlvdb = tlvdb->parent; | |
432 | } | |
433 | ||
434 | return NULL; | |
435 | } | |
436 | ||
437 | const struct tlv *tlvdb_get(const struct tlvdb *tlvdb, tlv_tag_t tag, const struct tlv *prev) | |
438 | { | |
439 | if (prev) { | |
440 | // tlvdb = tlvdb_next(container_of(prev, struct tlvdb, tag)); | |
441 | tlvdb = tlvdb_next((struct tlvdb *)prev); | |
442 | } | |
443 | ||
444 | ||
445 | while (tlvdb) { | |
446 | if (tlvdb->tag.tag == tag) | |
447 | return &tlvdb->tag; | |
448 | ||
449 | tlvdb = tlvdb_next(tlvdb); | |
450 | } | |
451 | ||
452 | return NULL; | |
453 | } | |
454 | ||
3c5fce2b OM |
455 | const struct tlv *tlvdb_get_inchild(const struct tlvdb *tlvdb, tlv_tag_t tag, const struct tlv *prev) { |
456 | tlvdb = tlvdb->children; | |
457 | return tlvdb_get(tlvdb, tag, prev); | |
458 | } | |
459 | ||
95b697f0 OM |
460 | const struct tlv *tlvdb_get_tlv(const struct tlvdb *tlvdb) { |
461 | return &tlvdb->tag; | |
462 | } | |
463 | ||
a2bb2735 | 464 | unsigned char *tlv_encode(const struct tlv *tlv, size_t *len) |
465 | { | |
466 | size_t size = tlv->len; | |
467 | unsigned char *data; | |
468 | size_t pos; | |
469 | ||
470 | if (tlv->tag > 0x100) | |
471 | size += 2; | |
472 | else | |
473 | size += 1; | |
474 | ||
475 | if (tlv->len > 0x7f) | |
476 | size += 2; | |
477 | else | |
478 | size += 1; | |
479 | ||
480 | data = malloc(size); | |
481 | if (!data) { | |
482 | *len = 0; | |
483 | return NULL; | |
484 | } | |
485 | ||
486 | pos = 0; | |
487 | ||
488 | if (tlv->tag > 0x100) { | |
489 | data[pos++] = tlv->tag >> 8; | |
490 | data[pos++] = tlv->tag & 0xff; | |
491 | } else | |
492 | data[pos++] = tlv->tag; | |
493 | ||
494 | if (tlv->len > 0x7f) { | |
495 | data[pos++] = 0x81; | |
496 | data[pos++] = tlv->len; | |
497 | } else | |
498 | data[pos++] = tlv->len; | |
499 | ||
500 | memcpy(data + pos, tlv->value, tlv->len); | |
501 | pos += tlv->len; | |
502 | ||
503 | *len = pos; | |
504 | return data; | |
505 | } | |
506 | ||
507 | bool tlv_is_constructed(const struct tlv *tlv) | |
508 | { | |
509 | return (tlv->tag < 0x100 ? tlv->tag : tlv->tag >> 8) & TLV_TAG_COMPLEX; | |
510 | } | |
511 | ||
512 | bool tlv_equal(const struct tlv *a, const struct tlv *b) | |
513 | { | |
514 | if (!a && !b) | |
515 | return true; | |
516 | ||
517 | if (!a || !b) | |
518 | return false; | |
519 | ||
520 | return a->tag == b->tag && a->len == b->len && !memcmp(a->value, b->value, a->len); | |
521 | } | |
95b697f0 OM |
522 | |
523 | struct tlvdb *tlvdb_elm_get_next(struct tlvdb *tlvdb) | |
524 | { | |
525 | return tlvdb->next; | |
526 | } | |
527 | ||
528 | struct tlvdb *tlvdb_elm_get_children(struct tlvdb *tlvdb) | |
529 | { | |
530 | return tlvdb->children; | |
531 | } | |
532 | ||
533 | struct tlvdb *tlvdb_elm_get_parent(struct tlvdb *tlvdb) | |
534 | { | |
535 | return tlvdb->parent; | |
536 | } |