1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file der_decode_sequence_flexi.c
15 ASN.1 DER, decode an array of ASN.1 types with a flexi parser, Tom St Denis
16 */
17
18 #ifdef LTC_DER
19
fetch_length(const unsigned char * in,unsigned long inlen)20 static unsigned long fetch_length(const unsigned char *in, unsigned long inlen)
21 {
22 unsigned long x, y, z;
23
24 y = 0;
25
26 /* skip type and read len */
27 if (inlen < 2) {
28 return 0xFFFFFFFF;
29 }
30 ++in; ++y;
31
32 /* read len */
33 x = *in++; ++y;
34
35 /* <128 means literal */
36 if (x < 128) {
37 return x+y;
38 }
39 x &= 0x7F; /* the lower 7 bits are the length of the length */
40 inlen -= 2;
41
42 /* len means len of len! */
43 if (x == 0 || x > 4 || x > inlen) {
44 return 0xFFFFFFFF;
45 }
46
47 y += x;
48 z = 0;
49 while (x--) {
50 z = (z<<8) | ((unsigned long)*in);
51 ++in;
52 }
53 return z+y;
54 }
55
56 /**
57 ASN.1 DER Flexi(ble) decoder will decode arbitrary DER packets and create a linked list of the decoded elements.
58 @param in The input buffer
59 @param inlen [in/out] The length of the input buffer and on output the amount of decoded data
60 @param out [out] A pointer to the linked list
61 @return CRYPT_OK on success.
62 */
der_decode_sequence_flexi(const unsigned char * in,unsigned long * inlen,ltc_asn1_list ** out)63 int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc_asn1_list **out)
64 {
65 ltc_asn1_list *l;
66 unsigned long err, type, len, totlen, x, y;
67 void *realloc_tmp;
68
69 LTC_ARGCHK(in != NULL);
70 LTC_ARGCHK(inlen != NULL);
71 LTC_ARGCHK(out != NULL);
72
73 l = NULL;
74 totlen = 0;
75
76 /* scan the input and and get lengths and what not */
77 while (*inlen) {
78 /* read the type byte */
79 type = *in;
80
81 /* fetch length */
82 len = fetch_length(in, *inlen);
83 if (len > *inlen) {
84 err = CRYPT_INVALID_PACKET;
85 goto error;
86 }
87
88 /* alloc new link */
89 if (l == NULL) {
90 l = XCALLOC(1, sizeof(*l));
91 if (l == NULL) {
92 err = CRYPT_MEM;
93 goto error;
94 }
95 } else {
96 l->next = XCALLOC(1, sizeof(*l));
97 if (l->next == NULL) {
98 err = CRYPT_MEM;
99 goto error;
100 }
101 l->next->prev = l;
102 l = l->next;
103 }
104
105 /* now switch on type */
106 switch (type) {
107 case 0x01: /* BOOLEAN */
108 l->type = LTC_ASN1_BOOLEAN;
109 l->size = 1;
110 l->data = XCALLOC(1, sizeof(int));
111
112 if ((err = der_decode_boolean(in, *inlen, l->data)) != CRYPT_OK) {
113 goto error;
114 }
115
116 if ((err = der_length_boolean(&len)) != CRYPT_OK) {
117 goto error;
118 }
119 break;
120
121 case 0x02: /* INTEGER */
122 /* init field */
123 l->type = LTC_ASN1_INTEGER;
124 l->size = 1;
125 if ((err = mp_init(&l->data)) != CRYPT_OK) {
126 goto error;
127 }
128
129 /* decode field */
130 if ((err = der_decode_integer(in, *inlen, l->data)) != CRYPT_OK) {
131 goto error;
132 }
133
134 /* calc length of object */
135 if ((err = der_length_integer(l->data, &len)) != CRYPT_OK) {
136 goto error;
137 }
138 break;
139
140 case 0x03: /* BIT */
141 /* init field */
142 l->type = LTC_ASN1_BIT_STRING;
143 l->size = len * 8; /* *8 because we store decoded bits one per char and they are encoded 8 per char. */
144
145 if ((l->data = XCALLOC(1, l->size)) == NULL) {
146 err = CRYPT_MEM;
147 goto error;
148 }
149
150 if ((err = der_decode_bit_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) {
151 goto error;
152 }
153
154 if ((err = der_length_bit_string(l->size, &len)) != CRYPT_OK) {
155 goto error;
156 }
157 break;
158
159 case 0x04: /* OCTET */
160
161 /* init field */
162 l->type = LTC_ASN1_OCTET_STRING;
163 l->size = len;
164
165 if ((l->data = XCALLOC(1, l->size)) == NULL) {
166 err = CRYPT_MEM;
167 goto error;
168 }
169
170 if ((err = der_decode_octet_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) {
171 goto error;
172 }
173
174 if ((err = der_length_octet_string(l->size, &len)) != CRYPT_OK) {
175 goto error;
176 }
177 break;
178
179 case 0x05: /* NULL */
180
181 /* valid NULL is 0x05 0x00 */
182 if (in[0] != 0x05 || in[1] != 0x00) {
183 err = CRYPT_INVALID_PACKET;
184 goto error;
185 }
186
187 /* simple to store ;-) */
188 l->type = LTC_ASN1_NULL;
189 l->data = NULL;
190 l->size = 0;
191 len = 2;
192
193 break;
194
195 case 0x06: /* OID */
196
197 /* init field */
198 l->type = LTC_ASN1_OBJECT_IDENTIFIER;
199 l->size = len;
200
201 if ((l->data = XCALLOC(len, sizeof(unsigned long))) == NULL) {
202 err = CRYPT_MEM;
203 goto error;
204 }
205
206 if ((err = der_decode_object_identifier(in, *inlen, l->data, &l->size)) != CRYPT_OK) {
207 goto error;
208 }
209
210 if ((err = der_length_object_identifier(l->data, l->size, &len)) != CRYPT_OK) {
211 goto error;
212 }
213
214 /* resize it to save a bunch of mem */
215 if ((realloc_tmp = XREALLOC(l->data, l->size * sizeof(unsigned long))) == NULL) {
216 /* out of heap but this is not an error */
217 break;
218 }
219 l->data = realloc_tmp;
220 break;
221
222 case 0x0C: /* UTF8 */
223
224 /* init field */
225 l->type = LTC_ASN1_UTF8_STRING;
226 l->size = len;
227
228 if ((l->data = XCALLOC(sizeof(wchar_t), l->size)) == NULL) {
229 err = CRYPT_MEM;
230 goto error;
231 }
232
233 if ((err = der_decode_utf8_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) {
234 goto error;
235 }
236
237 if ((err = der_length_utf8_string(l->data, l->size, &len)) != CRYPT_OK) {
238 goto error;
239 }
240 break;
241
242 case 0x13: /* PRINTABLE */
243
244 /* init field */
245 l->type = LTC_ASN1_PRINTABLE_STRING;
246 l->size = len;
247
248 if ((l->data = XCALLOC(1, l->size)) == NULL) {
249 err = CRYPT_MEM;
250 goto error;
251 }
252
253 if ((err = der_decode_printable_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) {
254 goto error;
255 }
256
257 if ((err = der_length_printable_string(l->data, l->size, &len)) != CRYPT_OK) {
258 goto error;
259 }
260 break;
261
262 case 0x16: /* IA5 */
263
264 /* init field */
265 l->type = LTC_ASN1_IA5_STRING;
266 l->size = len;
267
268 if ((l->data = XCALLOC(1, l->size)) == NULL) {
269 err = CRYPT_MEM;
270 goto error;
271 }
272
273 if ((err = der_decode_ia5_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) {
274 goto error;
275 }
276
277 if ((err = der_length_ia5_string(l->data, l->size, &len)) != CRYPT_OK) {
278 goto error;
279 }
280 break;
281
282 case 0x17: /* UTC TIME */
283
284 /* init field */
285 l->type = LTC_ASN1_UTCTIME;
286 l->size = 1;
287
288 if ((l->data = XCALLOC(1, sizeof(ltc_utctime))) == NULL) {
289 err = CRYPT_MEM;
290 goto error;
291 }
292
293 len = *inlen;
294 if ((err = der_decode_utctime(in, &len, l->data)) != CRYPT_OK) {
295 goto error;
296 }
297
298 if ((err = der_length_utctime(l->data, &len)) != CRYPT_OK) {
299 goto error;
300 }
301 break;
302
303 case 0x30: /* SEQUENCE */
304 case 0x31: /* SET */
305
306 /* init field */
307 l->type = (type == 0x30) ? LTC_ASN1_SEQUENCE : LTC_ASN1_SET;
308
309 /* we have to decode the SEQUENCE header and get it's length */
310
311 /* move past type */
312 ++in; --(*inlen);
313
314 /* read length byte */
315 x = *in++; --(*inlen);
316
317 /* smallest SEQUENCE/SET header */
318 y = 2;
319
320 /* now if it's > 127 the next bytes are the length of the length */
321 if (x > 128) {
322 x &= 0x7F;
323 in += x;
324 *inlen -= x;
325
326 /* update sequence header len */
327 y += x;
328 }
329
330 /* Sequence elements go as child */
331 len = len - y;
332 if ((err = der_decode_sequence_flexi(in, &len, &(l->child))) != CRYPT_OK) {
333 goto error;
334 }
335
336 /* len update */
337 totlen += y;
338
339 /* link them up y0 */
340 l->child->parent = l;
341
342 break;
343 default:
344 /* invalid byte ... this is a soft error */
345 /* remove link */
346 l = l->prev;
347 XFREE(l->next);
348 l->next = NULL;
349 goto outside;
350 }
351
352 /* advance pointers */
353 totlen += len;
354 in += len;
355 *inlen -= len;
356 }
357
358 outside:
359
360 /* rewind l please */
361 while (l->prev != NULL || l->parent != NULL) {
362 if (l->parent != NULL) {
363 l = l->parent;
364 } else {
365 l = l->prev;
366 }
367 }
368
369 /* return */
370 *out = l;
371 *inlen = totlen;
372 return CRYPT_OK;
373
374 error:
375 /* free list */
376 der_sequence_free(l);
377
378 return err;
379 }
380
381 #endif
382
383
384 /* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c,v $ */
385 /* $Revision: 1.25 $ */
386 /* $Date: 2006/11/26 02:25:18 $ */
387