Merge branch 'master' into 14a_rework3
[proxmark3-svn] / client / emv / tlv.c
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;
95 if (*len < ll)
96 return TLV_LEN_INVALID;
97
98 /* FIXME */
99 if (ll != 1)
100 return TLV_LEN_INVALID;
101
102 l = **buf;
103 --*len;
104 ++*buf;
105
106 return l;
107 }
108
109 bool tlv_parse_tl(const unsigned char **buf, size_t *len, struct tlv *tlv)
110 {
111 tlv->value = 0;
112
113 tlv->tag = tlv_parse_tag(buf, len);
114 if (tlv->tag == TLV_TAG_INVALID)
115 return false;
116
117 tlv->len = tlv_parse_len(buf, len);
118 if (tlv->len == TLV_LEN_INVALID)
119 return false;
120
121 return true;
122 }
123
124 static struct tlvdb *tlvdb_parse_children(struct tlvdb *parent);
125
126 static bool tlvdb_parse_one(struct tlvdb *tlvdb,
127 struct tlvdb *parent,
128 const unsigned char **tmp,
129 size_t *left)
130 {
131 tlvdb->next = tlvdb->children = NULL;
132 tlvdb->parent = parent;
133
134 tlvdb->tag.tag = tlv_parse_tag(tmp, left);
135 if (tlvdb->tag.tag == TLV_TAG_INVALID)
136 goto err;
137
138 tlvdb->tag.len = tlv_parse_len(tmp, left);
139 if (tlvdb->tag.len == TLV_LEN_INVALID)
140 goto err;
141
142 if (tlvdb->tag.len > *left)
143 goto err;
144
145 tlvdb->tag.value = *tmp;
146
147 *tmp += tlvdb->tag.len;
148 *left -= tlvdb->tag.len;
149
150 if (tlv_is_constructed(&tlvdb->tag) && (tlvdb->tag.len != 0)) {
151 tlvdb->children = tlvdb_parse_children(tlvdb);
152 if (!tlvdb->children)
153 goto err;
154 } else {
155 tlvdb->children = NULL;
156 }
157
158 return true;
159
160 err:
161 return false;
162 }
163
164 static struct tlvdb *tlvdb_parse_children(struct tlvdb *parent)
165 {
166 const unsigned char *tmp = parent->tag.value;
167 size_t left = parent->tag.len;
168 struct tlvdb *tlvdb, *first = NULL, *prev = NULL;
169
170 while (left != 0) {
171 tlvdb = malloc(sizeof(*tlvdb));
172 if (prev)
173 prev->next = tlvdb;
174 else
175 first = tlvdb;
176 prev = tlvdb;
177
178 if (!tlvdb_parse_one(tlvdb, parent, &tmp, &left))
179 goto err;
180
181 tlvdb->parent = parent;
182 }
183
184 return first;
185
186 err:
187 tlvdb_free(first);
188
189 return NULL;
190 }
191
192 struct tlvdb *tlvdb_parse(const unsigned char *buf, size_t len)
193 {
194 struct tlvdb_root *root;
195 const unsigned char *tmp;
196 size_t left;
197
198 if (!len || !buf)
199 return NULL;
200
201 root = malloc(sizeof(*root) + len);
202 root->len = len;
203 memcpy(root->buf, buf, len);
204
205 tmp = root->buf;
206 left = len;
207
208 if (!tlvdb_parse_one(&root->db, NULL, &tmp, &left))
209 goto err;
210
211 if (left)
212 goto err;
213
214 return &root->db;
215
216 err:
217 tlvdb_free(&root->db);
218
219 return NULL;
220 }
221
222 struct tlvdb *tlvdb_parse_multi(const unsigned char *buf, size_t len)
223 {
224 struct tlvdb_root *root;
225 const unsigned char *tmp;
226 size_t left;
227
228 if (!len || !buf)
229 return NULL;
230
231 root = malloc(sizeof(*root) + len);
232 root->len = len;
233 memcpy(root->buf, buf, len);
234
235 tmp = root->buf;
236 left = len;
237
238 if (!tlvdb_parse_one(&root->db, NULL, &tmp, &left))
239 goto err;
240
241 while (left != 0) {
242 struct tlvdb *db = malloc(sizeof(*db));
243 if (!tlvdb_parse_one(db, NULL, &tmp, &left)) {
244 free (db);
245 goto err;
246 }
247
248 tlvdb_add(&root->db, db);
249 }
250
251 return &root->db;
252
253 err:
254 tlvdb_free(&root->db);
255
256 return NULL;
257 }
258
259 struct tlvdb *tlvdb_fixed(tlv_tag_t tag, size_t len, const unsigned char *value)
260 {
261 struct tlvdb_root *root = malloc(sizeof(*root) + len);
262
263 root->len = len;
264 memcpy(root->buf, value, len);
265
266 root->db.parent = root->db.next = root->db.children = NULL;
267 root->db.tag.tag = tag;
268 root->db.tag.len = len;
269 root->db.tag.value = root->buf;
270
271 return &root->db;
272 }
273
274 struct tlvdb *tlvdb_external(tlv_tag_t tag, size_t len, const unsigned char *value)
275 {
276 struct tlvdb_root *root = malloc(sizeof(*root));
277
278 root->len = 0;
279
280 root->db.parent = root->db.next = root->db.children = NULL;
281 root->db.tag.tag = tag;
282 root->db.tag.len = len;
283 root->db.tag.value = value;
284
285 return &root->db;
286 }
287
288 void tlvdb_free(struct tlvdb *tlvdb)
289 {
290 struct tlvdb *next = NULL;
291
292 if (!tlvdb)
293 return;
294
295 for (; tlvdb; tlvdb = next) {
296 next = tlvdb->next;
297 tlvdb_free(tlvdb->children);
298 free(tlvdb);
299 }
300 }
301
302 void tlvdb_add(struct tlvdb *tlvdb, struct tlvdb *other)
303 {
304 while (tlvdb->next) {
305 tlvdb = tlvdb->next;
306 }
307
308 tlvdb->next = other;
309 }
310
311 void tlvdb_visit(const struct tlvdb *tlvdb, tlv_cb cb, void *data)
312 {
313 struct tlvdb *next = NULL;
314
315 if (!tlvdb)
316 return;
317
318 for (; tlvdb; tlvdb = next) {
319 next = tlvdb->next;
320 cb(data, &tlvdb->tag);
321 tlvdb_visit(tlvdb->children, cb, data);
322 }
323 }
324
325 static const struct tlvdb *tlvdb_next(const struct tlvdb *tlvdb)
326 {
327 if (tlvdb->children)
328 return tlvdb->children;
329
330 while (tlvdb) {
331 if (tlvdb->next)
332 return tlvdb->next;
333
334 tlvdb = tlvdb->parent;
335 }
336
337 return NULL;
338 }
339
340 const struct tlv *tlvdb_get(const struct tlvdb *tlvdb, tlv_tag_t tag, const struct tlv *prev)
341 {
342 if (prev) {
343 // tlvdb = tlvdb_next(container_of(prev, struct tlvdb, tag));
344 tlvdb = tlvdb_next((struct tlvdb *)prev);
345 }
346
347
348 while (tlvdb) {
349 if (tlvdb->tag.tag == tag)
350 return &tlvdb->tag;
351
352 tlvdb = tlvdb_next(tlvdb);
353 }
354
355 return NULL;
356 }
357
358 unsigned char *tlv_encode(const struct tlv *tlv, size_t *len)
359 {
360 size_t size = tlv->len;
361 unsigned char *data;
362 size_t pos;
363
364 if (tlv->tag > 0x100)
365 size += 2;
366 else
367 size += 1;
368
369 if (tlv->len > 0x7f)
370 size += 2;
371 else
372 size += 1;
373
374 data = malloc(size);
375 if (!data) {
376 *len = 0;
377 return NULL;
378 }
379
380 pos = 0;
381
382 if (tlv->tag > 0x100) {
383 data[pos++] = tlv->tag >> 8;
384 data[pos++] = tlv->tag & 0xff;
385 } else
386 data[pos++] = tlv->tag;
387
388 if (tlv->len > 0x7f) {
389 data[pos++] = 0x81;
390 data[pos++] = tlv->len;
391 } else
392 data[pos++] = tlv->len;
393
394 memcpy(data + pos, tlv->value, tlv->len);
395 pos += tlv->len;
396
397 *len = pos;
398 return data;
399 }
400
401 bool tlv_is_constructed(const struct tlv *tlv)
402 {
403 return (tlv->tag < 0x100 ? tlv->tag : tlv->tag >> 8) & TLV_TAG_COMPLEX;
404 }
405
406 bool tlv_equal(const struct tlv *a, const struct tlv *b)
407 {
408 if (!a && !b)
409 return true;
410
411 if (!a || !b)
412 return false;
413
414 return a->tag == b->tag && a->len == b->len && !memcmp(a->value, b->value, a->len);
415 }
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