1 /*
2 * Generic ASN.1 parsing
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 *
7 * This file is provided under the Apache License 2.0, or the
8 * GNU General Public License v2.0 or later.
9 *
10 * **********
11 * Apache License 2.0:
12 *
13 * Licensed under the Apache License, Version 2.0 (the "License"); you may
14 * not use this file except in compliance with the License.
15 * You may obtain a copy of the License at
16 *
17 * http://www.apache.org/licenses/LICENSE-2.0
18 *
19 * Unless required by applicable law or agreed to in writing, software
20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22 * See the License for the specific language governing permissions and
23 * limitations under the License.
24 *
25 * **********
26 *
27 * **********
28 * GNU General Public License v2.0 or later:
29 *
30 * This program is free software; you can redistribute it and/or modify
31 * it under the terms of the GNU General Public License as published by
32 * the Free Software Foundation; either version 2 of the License, or
33 * (at your option) any later version.
34 *
35 * This program is distributed in the hope that it will be useful,
36 * but WITHOUT ANY WARRANTY; without even the implied warranty of
37 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
38 * GNU General Public License for more details.
39 *
40 * You should have received a copy of the GNU General Public License along
41 * with this program; if not, write to the Free Software Foundation, Inc.,
42 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
43 *
44 * **********
45 */
46
47 #if !defined(MBEDTLS_CONFIG_FILE)
48 #include "mbedtls/config.h"
49 #else
50 #include MBEDTLS_CONFIG_FILE
51 #endif
52
53 #if defined(MBEDTLS_ASN1_PARSE_C)
54
55 #include "mbedtls/asn1.h"
56 #include "mbedtls/platform_util.h"
57
58 #include <string.h>
59
60 #if defined(MBEDTLS_BIGNUM_C)
61 #include "mbedtls/bignum.h"
62 #endif
63
64 #if defined(MBEDTLS_PLATFORM_C)
65 #include "mbedtls/platform.h"
66 #else
67 #include <stdlib.h>
68 #define mbedtls_calloc calloc
69 #define mbedtls_free free
70 #endif
71
72 /*
73 * ASN.1 DER decoding routines
74 */
mbedtls_asn1_get_len(unsigned char ** p,const unsigned char * end,size_t * len)75 int mbedtls_asn1_get_len( unsigned char **p,
76 const unsigned char *end,
77 size_t *len )
78 {
79 if( ( end - *p ) < 1 )
80 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
81
82 if( ( **p & 0x80 ) == 0 )
83 *len = *(*p)++;
84 else
85 {
86 switch( **p & 0x7F )
87 {
88 case 1:
89 if( ( end - *p ) < 2 )
90 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
91
92 *len = (*p)[1];
93 (*p) += 2;
94 break;
95
96 case 2:
97 if( ( end - *p ) < 3 )
98 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
99
100 *len = ( (size_t)(*p)[1] << 8 ) | (*p)[2];
101 (*p) += 3;
102 break;
103
104 case 3:
105 if( ( end - *p ) < 4 )
106 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
107
108 *len = ( (size_t)(*p)[1] << 16 ) |
109 ( (size_t)(*p)[2] << 8 ) | (*p)[3];
110 (*p) += 4;
111 break;
112
113 case 4:
114 if( ( end - *p ) < 5 )
115 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
116
117 *len = ( (size_t)(*p)[1] << 24 ) | ( (size_t)(*p)[2] << 16 ) |
118 ( (size_t)(*p)[3] << 8 ) | (*p)[4];
119 (*p) += 5;
120 break;
121
122 default:
123 return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
124 }
125 }
126
127 if( *len > (size_t) ( end - *p ) )
128 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
129
130 return( 0 );
131 }
132
mbedtls_asn1_get_tag(unsigned char ** p,const unsigned char * end,size_t * len,int tag)133 int mbedtls_asn1_get_tag( unsigned char **p,
134 const unsigned char *end,
135 size_t *len, int tag )
136 {
137 if( ( end - *p ) < 1 )
138 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
139
140 if( **p != tag )
141 return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
142
143 (*p)++;
144
145 return( mbedtls_asn1_get_len( p, end, len ) );
146 }
147
mbedtls_asn1_get_bool(unsigned char ** p,const unsigned char * end,int * val)148 int mbedtls_asn1_get_bool( unsigned char **p,
149 const unsigned char *end,
150 int *val )
151 {
152 int ret;
153 size_t len;
154
155 if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_BOOLEAN ) ) != 0 )
156 return( ret );
157
158 if( len != 1 )
159 return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
160
161 *val = ( **p != 0 ) ? 1 : 0;
162 (*p)++;
163
164 return( 0 );
165 }
166
mbedtls_asn1_get_int(unsigned char ** p,const unsigned char * end,int * val)167 int mbedtls_asn1_get_int( unsigned char **p,
168 const unsigned char *end,
169 int *val )
170 {
171 int ret;
172 size_t len;
173
174 if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )
175 return( ret );
176
177 if( len == 0 || len > sizeof( int ) || ( **p & 0x80 ) != 0 )
178 return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
179
180 *val = 0;
181
182 while( len-- > 0 )
183 {
184 *val = ( *val << 8 ) | **p;
185 (*p)++;
186 }
187
188 return( 0 );
189 }
190
191 #if defined(MBEDTLS_BIGNUM_C)
mbedtls_asn1_get_mpi(unsigned char ** p,const unsigned char * end,mbedtls_mpi * X)192 int mbedtls_asn1_get_mpi( unsigned char **p,
193 const unsigned char *end,
194 mbedtls_mpi *X )
195 {
196 int ret;
197 size_t len;
198
199 if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )
200 return( ret );
201
202 ret = mbedtls_mpi_read_binary( X, *p, len );
203
204 *p += len;
205
206 return( ret );
207 }
208 #endif /* MBEDTLS_BIGNUM_C */
209
mbedtls_asn1_get_bitstring(unsigned char ** p,const unsigned char * end,mbedtls_asn1_bitstring * bs)210 int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end,
211 mbedtls_asn1_bitstring *bs)
212 {
213 int ret;
214
215 /* Certificate type is a single byte bitstring */
216 if( ( ret = mbedtls_asn1_get_tag( p, end, &bs->len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 )
217 return( ret );
218
219 /* Check length, subtract one for actual bit string length */
220 if( bs->len < 1 )
221 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
222 bs->len -= 1;
223
224 /* Get number of unused bits, ensure unused bits <= 7 */
225 bs->unused_bits = **p;
226 if( bs->unused_bits > 7 )
227 return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
228 (*p)++;
229
230 /* Get actual bitstring */
231 bs->p = *p;
232 *p += bs->len;
233
234 if( *p != end )
235 return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
236
237 return( 0 );
238 }
239
240 /*
241 * Get a bit string without unused bits
242 */
mbedtls_asn1_get_bitstring_null(unsigned char ** p,const unsigned char * end,size_t * len)243 int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,
244 size_t *len )
245 {
246 int ret;
247
248 if( ( ret = mbedtls_asn1_get_tag( p, end, len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 )
249 return( ret );
250
251 if( (*len)-- < 2 || *(*p)++ != 0 )
252 return( MBEDTLS_ERR_ASN1_INVALID_DATA );
253
254 return( 0 );
255 }
256
257
258
259 /*
260 * Parses and splits an ASN.1 "SEQUENCE OF <tag>"
261 */
mbedtls_asn1_get_sequence_of(unsigned char ** p,const unsigned char * end,mbedtls_asn1_sequence * cur,int tag)262 int mbedtls_asn1_get_sequence_of( unsigned char **p,
263 const unsigned char *end,
264 mbedtls_asn1_sequence *cur,
265 int tag)
266 {
267 int ret;
268 size_t len;
269 mbedtls_asn1_buf *buf;
270
271 /* Get main sequence tag */
272 if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
273 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
274 return( ret );
275
276 if( *p + len != end )
277 return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
278
279 while( *p < end )
280 {
281 buf = &(cur->buf);
282 buf->tag = **p;
283
284 if( ( ret = mbedtls_asn1_get_tag( p, end, &buf->len, tag ) ) != 0 )
285 return( ret );
286
287 buf->p = *p;
288 *p += buf->len;
289
290 /* Allocate and assign next pointer */
291 if( *p < end )
292 {
293 cur->next = (mbedtls_asn1_sequence*)mbedtls_calloc( 1,
294 sizeof( mbedtls_asn1_sequence ) );
295
296 if( cur->next == NULL )
297 return( MBEDTLS_ERR_ASN1_ALLOC_FAILED );
298
299 cur = cur->next;
300 }
301 }
302
303 /* Set final sequence entry's next pointer to NULL */
304 cur->next = NULL;
305
306 if( *p != end )
307 return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
308
309 return( 0 );
310 }
311
mbedtls_asn1_get_alg(unsigned char ** p,const unsigned char * end,mbedtls_asn1_buf * alg,mbedtls_asn1_buf * params)312 int mbedtls_asn1_get_alg( unsigned char **p,
313 const unsigned char *end,
314 mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params )
315 {
316 int ret;
317 size_t len;
318
319 if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
320 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
321 return( ret );
322
323 if( ( end - *p ) < 1 )
324 return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
325
326 alg->tag = **p;
327 end = *p + len;
328
329 if( ( ret = mbedtls_asn1_get_tag( p, end, &alg->len, MBEDTLS_ASN1_OID ) ) != 0 )
330 return( ret );
331
332 alg->p = *p;
333 *p += alg->len;
334
335 if( *p == end )
336 {
337 mbedtls_platform_zeroize( params, sizeof(mbedtls_asn1_buf) );
338 return( 0 );
339 }
340
341 params->tag = **p;
342 (*p)++;
343
344 if( ( ret = mbedtls_asn1_get_len( p, end, ¶ms->len ) ) != 0 )
345 return( ret );
346
347 params->p = *p;
348 *p += params->len;
349
350 if( *p != end )
351 return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
352
353 return( 0 );
354 }
355
mbedtls_asn1_get_alg_null(unsigned char ** p,const unsigned char * end,mbedtls_asn1_buf * alg)356 int mbedtls_asn1_get_alg_null( unsigned char **p,
357 const unsigned char *end,
358 mbedtls_asn1_buf *alg )
359 {
360 int ret;
361 mbedtls_asn1_buf params;
362
363 memset( ¶ms, 0, sizeof(mbedtls_asn1_buf) );
364
365 if( ( ret = mbedtls_asn1_get_alg( p, end, alg, ¶ms ) ) != 0 )
366 return( ret );
367
368 if( ( params.tag != MBEDTLS_ASN1_NULL && params.tag != 0 ) || params.len != 0 )
369 return( MBEDTLS_ERR_ASN1_INVALID_DATA );
370
371 return( 0 );
372 }
373
mbedtls_asn1_free_named_data(mbedtls_asn1_named_data * cur)374 void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *cur )
375 {
376 if( cur == NULL )
377 return;
378
379 mbedtls_free( cur->oid.p );
380 mbedtls_free( cur->val.p );
381
382 mbedtls_platform_zeroize( cur, sizeof( mbedtls_asn1_named_data ) );
383 }
384
mbedtls_asn1_free_named_data_list(mbedtls_asn1_named_data ** head)385 void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head )
386 {
387 mbedtls_asn1_named_data *cur;
388
389 while( ( cur = *head ) != NULL )
390 {
391 *head = cur->next;
392 mbedtls_asn1_free_named_data( cur );
393 mbedtls_free( cur );
394 }
395 }
396
mbedtls_asn1_find_named_data(mbedtls_asn1_named_data * list,const char * oid,size_t len)397 mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,
398 const char *oid, size_t len )
399 {
400 while( list != NULL )
401 {
402 if( list->oid.len == len &&
403 memcmp( list->oid.p, oid, len ) == 0 )
404 {
405 break;
406 }
407
408 list = list->next;
409 }
410
411 return( list );
412 }
413
414 #endif /* MBEDTLS_ASN1_PARSE_C */
415