Coverage Report

Created: 2024-01-17 17:03

/src/mbedtls/library/asn1parse.c
Line
Count
Source (jump to first uncovered line)
1
/*
2
 *  Generic ASN.1 parsing
3
 *
4
 *  Copyright The Mbed TLS Contributors
5
 *  SPDX-License-Identifier: Apache-2.0
6
 *
7
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
8
 *  not use this file except in compliance with the License.
9
 *  You may obtain a copy of the License at
10
 *
11
 *  http://www.apache.org/licenses/LICENSE-2.0
12
 *
13
 *  Unless required by applicable law or agreed to in writing, software
14
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16
 *  See the License for the specific language governing permissions and
17
 *  limitations under the License.
18
 */
19
20
#include "common.h"
21
22
#if defined(MBEDTLS_ASN1_PARSE_C)
23
24
#include "mbedtls/asn1.h"
25
#include "mbedtls/platform_util.h"
26
#include "mbedtls/error.h"
27
28
#include <string.h>
29
30
#if defined(MBEDTLS_BIGNUM_C)
31
#include "mbedtls/bignum.h"
32
#endif
33
34
#include "mbedtls/platform.h"
35
36
/*
37
 * ASN.1 DER decoding routines
38
 */
39
int mbedtls_asn1_get_len(unsigned char **p,
40
                         const unsigned char *end,
41
                         size_t *len)
42
1.25M
{
43
1.25M
    if ((end - *p) < 1) {
44
76
        return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
45
76
    }
46
47
1.25M
    if ((**p & 0x80) == 0) {
48
1.10M
        *len = *(*p)++;
49
1.10M
    } else {
50
151k
        switch (**p & 0x7F) {
51
19.0k
            case 1:
52
19.0k
                if ((end - *p) < 2) {
53
36
                    return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
54
36
                }
55
56
19.0k
                *len = (*p)[1];
57
19.0k
                (*p) += 2;
58
19.0k
                break;
59
60
132k
            case 2:
61
132k
                if ((end - *p) < 3) {
62
50
                    return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
63
50
                }
64
65
132k
                *len = ((size_t) (*p)[1] << 8) | (*p)[2];
66
132k
                (*p) += 3;
67
132k
                break;
68
69
113
            case 3:
70
113
                if ((end - *p) < 4) {
71
49
                    return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
72
49
                }
73
74
64
                *len = ((size_t) (*p)[1] << 16) |
75
64
                       ((size_t) (*p)[2] << 8) | (*p)[3];
76
64
                (*p) += 4;
77
64
                break;
78
79
104
            case 4:
80
104
                if ((end - *p) < 5) {
81
50
                    return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
82
50
                }
83
84
54
                *len = ((size_t) (*p)[1] << 24) | ((size_t) (*p)[2] << 16) |
85
54
                       ((size_t) (*p)[3] << 8) |           (*p)[4];
86
54
                (*p) += 5;
87
54
                break;
88
89
346
            default:
90
346
                return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
91
151k
        }
92
151k
    }
93
94
1.25M
    if (*len > (size_t) (end - *p)) {
95
563
        return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
96
563
    }
97
98
1.25M
    return 0;
99
1.25M
}
100
101
int mbedtls_asn1_get_tag(unsigned char **p,
102
                         const unsigned char *end,
103
                         size_t *len, int tag)
104
1.09M
{
105
1.09M
    if ((end - *p) < 1) {
106
79
        return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
107
79
    }
108
109
1.09M
    if (**p != tag) {
110
90.4k
        return MBEDTLS_ERR_ASN1_UNEXPECTED_TAG;
111
90.4k
    }
112
113
1.00M
    (*p)++;
114
115
1.00M
    return mbedtls_asn1_get_len(p, end, len);
116
1.09M
}
117
118
int mbedtls_asn1_get_bool(unsigned char **p,
119
                          const unsigned char *end,
120
                          int *val)
121
66.3k
{
122
66.3k
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
123
66.3k
    size_t len;
124
125
66.3k
    if ((ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_BOOLEAN)) != 0) {
126
53.2k
        return ret;
127
53.2k
    }
128
129
13.1k
    if (len != 1) {
130
15
        return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
131
15
    }
132
133
13.1k
    *val = (**p != 0) ? 1 : 0;
134
13.1k
    (*p)++;
135
136
13.1k
    return 0;
137
13.1k
}
138
139
static int asn1_get_tagged_int(unsigned char **p,
140
                               const unsigned char *end,
141
                               int tag, int *val)
142
27.9k
{
143
27.9k
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
144
27.9k
    size_t len;
145
146
27.9k
    if ((ret = mbedtls_asn1_get_tag(p, end, &len, tag)) != 0) {
147
188
        return ret;
148
188
    }
149
150
    /*
151
     * len==0 is malformed (0 must be represented as 020100 for INTEGER,
152
     * or 0A0100 for ENUMERATED tags
153
     */
154
27.7k
    if (len == 0) {
155
12
        return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
156
12
    }
157
    /* This is a cryptography library. Reject negative integers. */
158
27.7k
    if ((**p & 0x80) != 0) {
159
18
        return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
160
18
    }
161
162
    /* Skip leading zeros. */
163
31.7k
    while (len > 0 && **p == 0) {
164
3.99k
        ++(*p);
165
3.99k
        --len;
166
3.99k
    }
167
168
    /* Reject integers that don't fit in an int. This code assumes that
169
     * the int type has no padding bit. */
170
27.7k
    if (len > sizeof(int)) {
171
85
        return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
172
85
    }
173
27.6k
    if (len == sizeof(int) && (**p & 0x80) != 0) {
174
13
        return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
175
13
    }
176
177
27.6k
    *val = 0;
178
55.2k
    while (len-- > 0) {
179
27.6k
        *val = (*val << 8) | **p;
180
27.6k
        (*p)++;
181
27.6k
    }
182
183
27.6k
    return 0;
184
27.6k
}
185
186
int mbedtls_asn1_get_int(unsigned char **p,
187
                         const unsigned char *end,
188
                         int *val)
189
27.9k
{
190
27.9k
    return asn1_get_tagged_int(p, end, MBEDTLS_ASN1_INTEGER, val);
191
27.9k
}
192
193
int mbedtls_asn1_get_enum(unsigned char **p,
194
                          const unsigned char *end,
195
                          int *val)
196
0
{
197
0
    return asn1_get_tagged_int(p, end, MBEDTLS_ASN1_ENUMERATED, val);
198
0
}
199
200
#if defined(MBEDTLS_BIGNUM_C)
201
int mbedtls_asn1_get_mpi(unsigned char **p,
202
                         const unsigned char *end,
203
                         mbedtls_mpi *X)
204
0
{
205
0
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
206
0
    size_t len;
207
208
0
    if ((ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
209
0
        return ret;
210
0
    }
211
212
0
    ret = mbedtls_mpi_read_binary(X, *p, len);
213
214
0
    *p += len;
215
216
0
    return ret;
217
0
}
218
#endif /* MBEDTLS_BIGNUM_C */
219
220
int mbedtls_asn1_get_bitstring(unsigned char **p, const unsigned char *end,
221
                               mbedtls_asn1_bitstring *bs)
222
44
{
223
44
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
224
225
    /* Certificate type is a single byte bitstring */
226
44
    if ((ret = mbedtls_asn1_get_tag(p, end, &bs->len, MBEDTLS_ASN1_BIT_STRING)) != 0) {
227
21
        return ret;
228
21
    }
229
230
    /* Check length, subtract one for actual bit string length */
231
23
    if (bs->len < 1) {
232
0
        return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
233
0
    }
234
23
    bs->len -= 1;
235
236
    /* Get number of unused bits, ensure unused bits <= 7 */
237
23
    bs->unused_bits = **p;
238
23
    if (bs->unused_bits > 7) {
239
9
        return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
240
9
    }
241
14
    (*p)++;
242
243
    /* Get actual bitstring */
244
14
    bs->p = *p;
245
14
    *p += bs->len;
246
247
14
    if (*p != end) {
248
9
        return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
249
9
    }
250
251
5
    return 0;
252
14
}
253
254
/*
255
 * Traverse an ASN.1 "SEQUENCE OF <tag>"
256
 * and call a callback for each entry found.
257
 */
258
int mbedtls_asn1_traverse_sequence_of(
259
    unsigned char **p,
260
    const unsigned char *end,
261
    unsigned char tag_must_mask, unsigned char tag_must_val,
262
    unsigned char tag_may_mask, unsigned char tag_may_val,
263
    int (*cb)(void *ctx, int tag,
264
              unsigned char *start, size_t len),
265
    void *ctx)
266
215
{
267
215
    int ret;
268
215
    size_t len;
269
270
    /* Get main sequence tag */
271
215
    if ((ret = mbedtls_asn1_get_tag(p, end, &len,
272
215
                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
273
96
        return ret;
274
96
    }
275
276
119
    if (*p + len != end) {
277
13
        return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
278
13
    }
279
280
223
    while (*p < end) {
281
196
        unsigned char const tag = *(*p)++;
282
283
196
        if ((tag & tag_must_mask) != tag_must_val) {
284
29
            return MBEDTLS_ERR_ASN1_UNEXPECTED_TAG;
285
29
        }
286
287
167
        if ((ret = mbedtls_asn1_get_len(p, end, &len)) != 0) {
288
50
            return ret;
289
50
        }
290
291
117
        if ((tag & tag_may_mask) == tag_may_val) {
292
117
            if (cb != NULL) {
293
117
                ret = cb(ctx, tag, *p, len);
294
117
                if (ret != 0) {
295
0
                    return ret;
296
0
                }
297
117
            }
298
117
        }
299
300
117
        *p += len;
301
117
    }
302
303
27
    return 0;
304
106
}
305
306
/*
307
 * Get a bit string without unused bits
308
 */
309
int mbedtls_asn1_get_bitstring_null(unsigned char **p, const unsigned char *end,
310
                                    size_t *len)
311
36.9k
{
312
36.9k
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
313
314
36.9k
    if ((ret = mbedtls_asn1_get_tag(p, end, len, MBEDTLS_ASN1_BIT_STRING)) != 0) {
315
71
        return ret;
316
71
    }
317
318
36.9k
    if (*len == 0) {
319
13
        return MBEDTLS_ERR_ASN1_INVALID_DATA;
320
13
    }
321
36.8k
    --(*len);
322
323
36.8k
    if (**p != 0) {
324
25
        return MBEDTLS_ERR_ASN1_INVALID_DATA;
325
25
    }
326
36.8k
    ++(*p);
327
328
36.8k
    return 0;
329
36.8k
}
330
331
void mbedtls_asn1_sequence_free(mbedtls_asn1_sequence *seq)
332
81.0k
{
333
81.4k
    while (seq != NULL) {
334
378
        mbedtls_asn1_sequence *next = seq->next;
335
378
        mbedtls_free(seq);
336
378
        seq = next;
337
378
    }
338
81.0k
}
339
340
typedef struct {
341
    int tag;
342
    mbedtls_asn1_sequence *cur;
343
} asn1_get_sequence_of_cb_ctx_t;
344
345
static int asn1_get_sequence_of_cb(void *ctx,
346
                                   int tag,
347
                                   unsigned char *start,
348
                                   size_t len)
349
117
{
350
117
    asn1_get_sequence_of_cb_ctx_t *cb_ctx =
351
117
        (asn1_get_sequence_of_cb_ctx_t *) ctx;
352
117
    mbedtls_asn1_sequence *cur =
353
117
        cb_ctx->cur;
354
355
117
    if (cur->buf.p != NULL) {
356
62
        cur->next =
357
62
            mbedtls_calloc(1, sizeof(mbedtls_asn1_sequence));
358
359
62
        if (cur->next == NULL) {
360
0
            return MBEDTLS_ERR_ASN1_ALLOC_FAILED;
361
0
        }
362
363
62
        cur = cur->next;
364
62
    }
365
366
117
    cur->buf.p = start;
367
117
    cur->buf.len = len;
368
117
    cur->buf.tag = tag;
369
370
117
    cb_ctx->cur = cur;
371
117
    return 0;
372
117
}
373
374
/*
375
 *  Parses and splits an ASN.1 "SEQUENCE OF <tag>"
376
 */
377
int mbedtls_asn1_get_sequence_of(unsigned char **p,
378
                                 const unsigned char *end,
379
                                 mbedtls_asn1_sequence *cur,
380
                                 int tag)
381
215
{
382
215
    asn1_get_sequence_of_cb_ctx_t cb_ctx = { tag, cur };
383
215
    memset(cur, 0, sizeof(mbedtls_asn1_sequence));
384
215
    return mbedtls_asn1_traverse_sequence_of(
385
215
        p, end, 0xFF, tag, 0, 0,
386
215
        asn1_get_sequence_of_cb, &cb_ctx);
387
215
}
388
389
int mbedtls_asn1_get_alg(unsigned char **p,
390
                         const unsigned char *end,
391
                         mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params)
392
64.9k
{
393
64.9k
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
394
64.9k
    size_t len;
395
396
64.9k
    if ((ret = mbedtls_asn1_get_tag(p, end, &len,
397
64.9k
                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
398
203
        return ret;
399
203
    }
400
401
64.7k
    if ((end - *p) < 1) {
402
0
        return MBEDTLS_ERR_ASN1_OUT_OF_DATA;
403
0
    }
404
405
64.7k
    alg->tag = **p;
406
64.7k
    end = *p + len;
407
408
64.7k
    if ((ret = mbedtls_asn1_get_tag(p, end, &alg->len, MBEDTLS_ASN1_OID)) != 0) {
409
80
        return ret;
410
80
    }
411
412
64.6k
    alg->p = *p;
413
64.6k
    *p += alg->len;
414
415
64.6k
    if (*p == end) {
416
6.34k
        mbedtls_platform_zeroize(params, sizeof(mbedtls_asn1_buf));
417
6.34k
        return 0;
418
6.34k
    }
419
420
58.2k
    params->tag = **p;
421
58.2k
    (*p)++;
422
423
58.2k
    if ((ret = mbedtls_asn1_get_len(p, end, &params->len)) != 0) {
424
92
        return ret;
425
92
    }
426
427
58.1k
    params->p = *p;
428
58.1k
    *p += params->len;
429
430
58.1k
    if (*p != end) {
431
6
        return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
432
6
    }
433
434
58.1k
    return 0;
435
58.1k
}
436
437
int mbedtls_asn1_get_alg_null(unsigned char **p,
438
                              const unsigned char *end,
439
                              mbedtls_asn1_buf *alg)
440
0
{
441
0
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
442
0
    mbedtls_asn1_buf params;
443
444
0
    memset(&params, 0, sizeof(mbedtls_asn1_buf));
445
446
0
    if ((ret = mbedtls_asn1_get_alg(p, end, alg, &params)) != 0) {
447
0
        return ret;
448
0
    }
449
450
0
    if ((params.tag != MBEDTLS_ASN1_NULL && params.tag != 0) || params.len != 0) {
451
0
        return MBEDTLS_ERR_ASN1_INVALID_DATA;
452
0
    }
453
454
0
    return 0;
455
0
}
456
457
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
458
void mbedtls_asn1_free_named_data(mbedtls_asn1_named_data *cur)
459
0
{
460
0
    if (cur == NULL) {
461
0
        return;
462
0
    }
463
464
0
    mbedtls_free(cur->oid.p);
465
0
    mbedtls_free(cur->val.p);
466
467
0
    mbedtls_platform_zeroize(cur, sizeof(mbedtls_asn1_named_data));
468
0
}
469
#endif /* MBEDTLS_DEPRECATED_REMOVED */
470
471
void mbedtls_asn1_free_named_data_list(mbedtls_asn1_named_data **head)
472
0
{
473
0
    mbedtls_asn1_named_data *cur;
474
475
0
    while ((cur = *head) != NULL) {
476
0
        *head = cur->next;
477
0
        mbedtls_free(cur->oid.p);
478
0
        mbedtls_free(cur->val.p);
479
0
        mbedtls_free(cur);
480
0
    }
481
0
}
482
483
void mbedtls_asn1_free_named_data_list_shallow(mbedtls_asn1_named_data *name)
484
54.5k
{
485
120k
    for (mbedtls_asn1_named_data *next; name != NULL; name = next) {
486
66.0k
        next = name->next;
487
66.0k
        mbedtls_free(name);
488
66.0k
    }
489
54.5k
}
490
491
const mbedtls_asn1_named_data *mbedtls_asn1_find_named_data(const mbedtls_asn1_named_data *list,
492
                                                            const char *oid, size_t len)
493
0
{
494
0
    while (list != NULL) {
495
0
        if (list->oid.len == len &&
496
0
            memcmp(list->oid.p, oid, len) == 0) {
497
0
            break;
498
0
        }
499
500
0
        list = list->next;
501
0
    }
502
503
0
    return list;
504
0
}
505
506
#endif /* MBEDTLS_ASN1_PARSE_C */