Use a generic list encoding rule we can use to specify the wrapped payload type
[strongswan.git] / src / libcharon / encoding / parser.c
1 /*
2 * Copyright (C) 2005-2009 Martin Willi
3 * Copyright (C) 2005 Jan Hutter
4 * Hochschule fuer Technik Rapperswil
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * for more details.
15 */
16
17 #include <stdlib.h>
18 #include <arpa/inet.h>
19 #include <string.h>
20
21 #include "parser.h"
22
23 #include <library.h>
24 #include <daemon.h>
25 #include <utils/linked_list.h>
26 #include <encoding/payloads/encodings.h>
27 #include <encoding/payloads/payload.h>
28 #include <encoding/payloads/sa_payload.h>
29 #include <encoding/payloads/proposal_substructure.h>
30 #include <encoding/payloads/transform_substructure.h>
31 #include <encoding/payloads/transform_attribute.h>
32 #include <encoding/payloads/ke_payload.h>
33 #include <encoding/payloads/nonce_payload.h>
34 #include <encoding/payloads/id_payload.h>
35 #include <encoding/payloads/notify_payload.h>
36 #include <encoding/payloads/encryption_payload.h>
37 #include <encoding/payloads/auth_payload.h>
38 #include <encoding/payloads/cert_payload.h>
39 #include <encoding/payloads/certreq_payload.h>
40 #include <encoding/payloads/ts_payload.h>
41 #include <encoding/payloads/delete_payload.h>
42 #include <encoding/payloads/vendor_id_payload.h>
43 #include <encoding/payloads/cp_payload.h>
44 #include <encoding/payloads/configuration_attribute.h>
45 #include <encoding/payloads/eap_payload.h>
46 #include <encoding/payloads/unknown_payload.h>
47
48
49 typedef struct private_parser_t private_parser_t;
50
51 /**
52 * Private data stored in a context.
53 *
54 * Contains pointers and counters to store current state.
55 */
56 struct private_parser_t {
57 /**
58 * Public members, see parser_t.
59 */
60 parser_t public;
61
62 /**
63 * Current bit for reading in input data.
64 */
65 u_int8_t bit_pos;
66
67 /**
68 * Current byte for reading in input data.
69 */
70 u_int8_t *byte_pos;
71
72 /**
73 * Input data to parse.
74 */
75 u_int8_t *input;
76
77 /**
78 * Roof of input, used for length-checking.
79 */
80 u_int8_t *input_roof;
81
82 /**
83 * Set of encoding rules for this parsing session.
84 */
85 encoding_rule_t *rules;
86 };
87
88 /**
89 * Log invalid length error
90 */
91 static bool short_input(private_parser_t *this, int number)
92 {
93 DBG1(DBG_ENC, " not enough input to parse rule %d %N",
94 number, encoding_type_names, this->rules[number].type);
95 return FALSE;
96 }
97
98 /**
99 * Log unaligned rules
100 */
101 static bool bad_bitpos(private_parser_t *this, int number)
102 {
103 DBG1(DBG_ENC, " found rule %d %N on bitpos %d",
104 number, encoding_type_names, this->rules[number].type, this->bit_pos);
105 return FALSE;
106 }
107
108 /**
109 * Parse a 4-Bit unsigned integer from the current parsing position.
110 */
111 static bool parse_uint4(private_parser_t *this, int rule_number,
112 u_int8_t *output_pos)
113 {
114 if (this->byte_pos + sizeof(u_int8_t) > this->input_roof)
115 {
116 return short_input(this, rule_number);
117 }
118 switch (this->bit_pos)
119 {
120 case 0:
121 if (output_pos)
122 {
123 *output_pos = *(this->byte_pos) >> 4;
124 }
125 this->bit_pos = 4;
126 break;
127 case 4:
128 if (output_pos)
129 {
130 *output_pos = *(this->byte_pos) & 0x0F;
131 }
132 this->bit_pos = 0;
133 this->byte_pos++;
134 break;
135 default:
136 return bad_bitpos(this, rule_number);
137 }
138 if (output_pos)
139 {
140 DBG3(DBG_ENC, " => %d", *output_pos);
141 }
142 return TRUE;
143 }
144
145 /**
146 * Parse a 8-Bit unsigned integer from the current parsing position.
147 */
148 static bool parse_uint8(private_parser_t *this, int rule_number,
149 u_int8_t *output_pos)
150 {
151 if (this->byte_pos + sizeof(u_int8_t) > this->input_roof)
152 {
153 return short_input(this, rule_number);
154 }
155 if (this->bit_pos)
156 {
157 return bad_bitpos(this, rule_number);
158 }
159 if (output_pos)
160 {
161 *output_pos = *(this->byte_pos);
162 DBG3(DBG_ENC, " => %d", *output_pos);
163 }
164 this->byte_pos++;
165 return TRUE;
166 }
167
168 /**
169 * Parse a 15-Bit unsigned integer from the current parsing position.
170 */
171 static bool parse_uint15(private_parser_t *this, int rule_number,
172 u_int16_t *output_pos)
173 {
174 if (this->byte_pos + sizeof(u_int16_t) > this->input_roof)
175 {
176 return short_input(this, rule_number);
177 }
178 if (this->bit_pos != 1)
179 {
180 return bad_bitpos(this, rule_number);
181 }
182 if (output_pos)
183 {
184 memcpy(output_pos, this->byte_pos, sizeof(u_int16_t));
185 *output_pos = ntohs(*output_pos) & ~0x8000;
186 DBG3(DBG_ENC, " => %d", *output_pos);
187 }
188 this->byte_pos += sizeof(u_int16_t);
189 this->bit_pos = 0;
190 return TRUE;
191 }
192
193 /**
194 * Parse a 16-Bit unsigned integer from the current parsing position.
195 */
196 static bool parse_uint16(private_parser_t *this, int rule_number,
197 u_int16_t *output_pos)
198 {
199 if (this->byte_pos + sizeof(u_int16_t) > this->input_roof)
200 {
201 return short_input(this, rule_number);
202 }
203 if (this->bit_pos)
204 {
205 return bad_bitpos(this, rule_number);
206 }
207 if (output_pos)
208 {
209 memcpy(output_pos, this->byte_pos, sizeof(u_int16_t));
210 *output_pos = ntohs(*output_pos);
211 DBG3(DBG_ENC, " => %d", *output_pos);
212 }
213 this->byte_pos += sizeof(u_int16_t);
214 return TRUE;
215 }
216 /**
217 * Parse a 32-Bit unsigned integer from the current parsing position.
218 */
219 static bool parse_uint32(private_parser_t *this, int rule_number,
220 u_int32_t *output_pos)
221 {
222 if (this->byte_pos + sizeof(u_int32_t) > this->input_roof)
223 {
224 return short_input(this, rule_number);
225 }
226 if (this->bit_pos)
227 {
228 return bad_bitpos(this, rule_number);
229 }
230 if (output_pos)
231 {
232 memcpy(output_pos, this->byte_pos, sizeof(u_int32_t));
233 *output_pos = ntohl(*output_pos);
234 DBG3(DBG_ENC, " => %d", *output_pos);
235 }
236 this->byte_pos += sizeof(u_int32_t);
237 return TRUE;
238 }
239
240 /**
241 * Parse a given amount of bytes and writes them to a specific location
242 */
243 static bool parse_bytes(private_parser_t *this, int rule_number,
244 u_int8_t *output_pos, int bytes)
245 {
246 if (this->byte_pos + bytes > this->input_roof)
247 {
248 return short_input(this, rule_number);
249 }
250 if (this->bit_pos)
251 {
252 return bad_bitpos(this, rule_number);
253 }
254 if (output_pos)
255 {
256 memcpy(output_pos, this->byte_pos, bytes);
257 DBG3(DBG_ENC, " => %b", output_pos, bytes);
258 }
259 this->byte_pos += bytes;
260 return TRUE;
261 }
262
263 /**
264 * Parse a single Bit from the current parsing position
265 */
266 static bool parse_bit(private_parser_t *this, int rule_number,
267 bool *output_pos)
268 {
269 if (this->byte_pos + sizeof(u_int8_t) > this->input_roof)
270 {
271 return short_input(this, rule_number);
272 }
273 if (output_pos)
274 {
275 u_int8_t mask;
276 mask = 0x01 << (7 - this->bit_pos);
277 *output_pos = *this->byte_pos & mask;
278
279 if (*output_pos)
280 { /* set to a "clean", comparable true */
281 *output_pos = TRUE;
282 }
283 DBG3(DBG_ENC, " => %d", *output_pos);
284 }
285 this->bit_pos = (this->bit_pos + 1) % 8;
286 if (this->bit_pos == 0)
287 {
288 this->byte_pos++;
289 }
290 return TRUE;
291 }
292
293 /**
294 * Parse substructures in a list.
295 */
296 static bool parse_list(private_parser_t *this, int rule_number,
297 linked_list_t **output_pos, payload_type_t payload_type, int length)
298 {
299 linked_list_t *list = *output_pos;
300
301 if (length < 0)
302 {
303 return short_input(this, rule_number);
304 }
305 if (this->bit_pos)
306 {
307 return bad_bitpos(this, rule_number);
308 }
309 while (length > 0)
310 {
311 u_int8_t *pos_before = this->byte_pos;
312 payload_t *payload;
313
314 DBG2(DBG_ENC, " %d bytes left, parsing recursively %N",
315 length, payload_type_names, payload_type);
316
317 if (this->public.parse_payload(&this->public, payload_type,
318 &payload) != SUCCESS)
319 {
320 DBG1(DBG_ENC, " parsing of a %N substructure failed",
321 payload_type_names, payload_type);
322 return FALSE;
323 }
324 list->insert_last(list, payload);
325 length -= this->byte_pos - pos_before;
326 }
327 if (length != 0)
328 { /* must yield exactly to zero */
329 DBG1(DBG_ENC, " length of %N substructure list invalid",
330 payload_type_names, payload_type);
331 return FALSE;
332 }
333 *output_pos = list;
334 return TRUE;
335 }
336
337 /**
338 * Parse data from current parsing position in a chunk.
339 */
340 static bool parse_chunk(private_parser_t *this, int rule_number,
341 chunk_t *output_pos, int length)
342 {
343 if (this->byte_pos + length > this->input_roof)
344 {
345 return short_input(this, rule_number);
346 }
347 if (this->bit_pos)
348 {
349 return bad_bitpos(this, rule_number);
350 }
351 if (output_pos)
352 {
353 *output_pos = chunk_alloc(length);
354 memcpy(output_pos->ptr, this->byte_pos, length);
355 DBG3(DBG_ENC, " => %b", output_pos->ptr, length);
356 }
357 this->byte_pos += length;
358 return TRUE;
359 }
360
361 METHOD(parser_t, parse_payload, status_t,
362 private_parser_t *this, payload_type_t payload_type, payload_t **payload)
363 {
364 payload_t *pld;
365 void *output;
366 int payload_length = 0, spi_size = 0, attribute_length = 0, header_length;
367 u_int16_t ts_type = 0;
368 bool attribute_format = FALSE;
369 int rule_number, rule_count;
370 encoding_rule_t *rule;
371
372 /* create instance of the payload to parse */
373 pld = payload_create(payload_type);
374
375 DBG2(DBG_ENC, "parsing %N payload, %d bytes left",
376 payload_type_names, payload_type, this->input_roof - this->byte_pos);
377
378 DBG3(DBG_ENC, "parsing payload from %b",
379 this->byte_pos, this->input_roof - this->byte_pos);
380
381 /* base pointer for output, avoids casting in every rule */
382 output = pld;
383
384 header_length = pld->get_header_length(pld);
385 /* parse the payload with its own rulse */
386 rule_count = pld->get_encoding_rules(pld, &this->rules);
387 for (rule_number = 0; rule_number < rule_count; rule_number++)
388 {
389 rule = &(this->rules[rule_number]);
390 DBG2(DBG_ENC, " parsing rule %d %N",
391 rule_number, encoding_type_names, rule->type);
392 switch (rule->type)
393 {
394 case U_INT_4:
395 {
396 if (!parse_uint4(this, rule_number, output + rule->offset))
397 {
398 pld->destroy(pld);
399 return PARSE_ERROR;
400 }
401 break;
402 }
403 case U_INT_8:
404 case RESERVED_BYTE:
405 {
406 if (!parse_uint8(this, rule_number, output + rule->offset))
407 {
408 pld->destroy(pld);
409 return PARSE_ERROR;
410 }
411 break;
412 }
413 case U_INT_16:
414 {
415 if (!parse_uint16(this, rule_number, output + rule->offset))
416 {
417 pld->destroy(pld);
418 return PARSE_ERROR;
419 }
420 break;
421 }
422 case U_INT_32:
423 case HEADER_LENGTH:
424 {
425 if (!parse_uint32(this, rule_number, output + rule->offset))
426 {
427 pld->destroy(pld);
428 return PARSE_ERROR;
429 }
430 break;
431 }
432 case IKE_SPI:
433 {
434 if (!parse_bytes(this, rule_number, output + rule->offset, 8))
435 {
436 pld->destroy(pld);
437 return PARSE_ERROR;
438 }
439 break;
440 }
441 case RESERVED_BIT:
442 case FLAG:
443 {
444 if (!parse_bit(this, rule_number, output + rule->offset))
445 {
446 pld->destroy(pld);
447 return PARSE_ERROR;
448 }
449 break;
450 }
451 case PAYLOAD_LENGTH:
452 {
453 if (!parse_uint16(this, rule_number, output + rule->offset))
454 {
455 pld->destroy(pld);
456 return PARSE_ERROR;
457 }
458 /* parsed u_int16 should be aligned */
459 payload_length = *(u_int16_t*)(output + rule->offset);
460 /* all payloads must have at least 4 bytes header */
461 if (payload_length < 4)
462 {
463 pld->destroy(pld);
464 return PARSE_ERROR;
465 }
466 break;
467 }
468 case SPI_SIZE:
469 {
470 if (!parse_uint8(this, rule_number, output + rule->offset))
471 {
472 pld->destroy(pld);
473 return PARSE_ERROR;
474 }
475 spi_size = *(u_int8_t*)(output + rule->offset);
476 break;
477 }
478 case SPI:
479 {
480 if (!parse_chunk(this, rule_number, output + rule->offset,
481 spi_size))
482 {
483 pld->destroy(pld);
484 return PARSE_ERROR;
485 }
486 break;
487 }
488 case PAYLOAD_LIST + PROPOSAL_SUBSTRUCTURE:
489 case PAYLOAD_LIST + PROPOSAL_SUBSTRUCTURE_V1:
490 case PAYLOAD_LIST + TRANSFORM_SUBSTRUCTURE:
491 case PAYLOAD_LIST + TRANSFORM_SUBSTRUCTURE_V1:
492 case PAYLOAD_LIST + TRANSFORM_ATTRIBUTE:
493 case PAYLOAD_LIST + TRANSFORM_ATTRIBUTE_V1:
494 case PAYLOAD_LIST + CONFIGURATION_ATTRIBUTE:
495 case PAYLOAD_LIST + TRAFFIC_SELECTOR_SUBSTRUCTURE:
496 {
497 if (payload_length < header_length ||
498 !parse_list(this, rule_number, output + rule->offset,
499 rule->type - PAYLOAD_LIST,
500 payload_length - header_length))
501 {
502 pld->destroy(pld);
503 return PARSE_ERROR;
504 }
505 break;
506 }
507 case CHUNK_DATA:
508 {
509 if (payload_length < header_length ||
510 !parse_chunk(this, rule_number, output + rule->offset,
511 payload_length - header_length))
512 {
513 pld->destroy(pld);
514 return PARSE_ERROR;
515 }
516 break;
517 }
518 case ATTRIBUTE_FORMAT:
519 {
520 if (!parse_bit(this, rule_number, output + rule->offset))
521 {
522 pld->destroy(pld);
523 return PARSE_ERROR;
524 }
525 attribute_format = *(bool*)(output + rule->offset);
526 break;
527 }
528 case ATTRIBUTE_TYPE:
529 {
530 if (!parse_uint15(this, rule_number, output + rule->offset))
531 {
532 pld->destroy(pld);
533 return PARSE_ERROR;
534 }
535 break;
536 }
537 case CONFIGURATION_ATTRIBUTE_LENGTH:
538 {
539 if (!parse_uint16(this, rule_number, output + rule->offset))
540 {
541 pld->destroy(pld);
542 return PARSE_ERROR;
543 }
544 attribute_length = *(u_int16_t*)(output + rule->offset);
545 break;
546 }
547 case ATTRIBUTE_LENGTH_OR_VALUE:
548 {
549 if (!parse_uint16(this, rule_number, output + rule->offset))
550 {
551 pld->destroy(pld);
552 return PARSE_ERROR;
553 }
554 attribute_length = *(u_int16_t*)(output + rule->offset);
555 break;
556 }
557 case ATTRIBUTE_VALUE:
558 {
559 if (attribute_format == FALSE &&
560 !parse_chunk(this, rule_number, output + rule->offset,
561 attribute_length))
562 {
563 pld->destroy(pld);
564 return PARSE_ERROR;
565 }
566 break;
567 }
568 case TS_TYPE:
569 {
570 if (!parse_uint8(this, rule_number, output + rule->offset))
571 {
572 pld->destroy(pld);
573 return PARSE_ERROR;
574 }
575 ts_type = *(u_int8_t*)(output + rule->offset);
576 break;
577 }
578 case ADDRESS:
579 {
580 int address_length = (ts_type == TS_IPV4_ADDR_RANGE) ? 4 : 16;
581
582 if (!parse_chunk(this, rule_number, output + rule->offset,
583 address_length))
584 {
585 pld->destroy(pld);
586 return PARSE_ERROR;
587 }
588 break;
589 }
590 default:
591 {
592 DBG1(DBG_ENC, " no rule to parse rule %d %N",
593 rule_number, encoding_type_names, rule->type);
594 pld->destroy(pld);
595 return PARSE_ERROR;
596 }
597 }
598 /* process next rulue */
599 rule++;
600 }
601
602 *payload = pld;
603 DBG2(DBG_ENC, "parsing %N payload finished",
604 payload_type_names, payload_type);
605 return SUCCESS;
606 }
607
608 METHOD(parser_t, get_remaining_byte_count, int,
609 private_parser_t *this)
610 {
611 return this->input_roof - this->byte_pos;
612 }
613
614 METHOD(parser_t, reset_context, void,
615 private_parser_t *this)
616 {
617 this->byte_pos = this->input;
618 this->bit_pos = 0;
619 }
620
621 METHOD(parser_t, destroy, void,
622 private_parser_t *this)
623 {
624 free(this);
625 }
626
627 /*
628 * Described in header.
629 */
630 parser_t *parser_create(chunk_t data)
631 {
632 private_parser_t *this;
633
634 INIT(this,
635 .public = {
636 .parse_payload = _parse_payload,
637 .reset_context = _reset_context,
638 .get_remaining_byte_count = _get_remaining_byte_count,
639 .destroy = _destroy,
640 },
641 .input = data.ptr,
642 .byte_pos = data.ptr,
643 .input_roof = data.ptr + data.len,
644 );
645
646 return &this->public;
647 }
648