implemented asn1_get_known_oid(), mapping OID index to ASN1 OID
[strongswan.git] / src / libstrongswan / asn1 / asn1.c
1 /*
2 * Copyright (C) 2006 Martin Will
3 * Copyright (C) 2000-2008 Andreas Steffen
4 *
5 * Hochschule fuer Technik Rapperswil
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * for more details.
16 *
17 * $Id$
18 */
19
20 #include <stdio.h>
21 #include <string.h>
22 #include <time.h>
23
24 #include <library.h>
25 #include <debug.h>
26
27 #include "oid.h"
28 #include "asn1.h"
29 #include "asn1_parser.h"
30
31 /**
32 * some common prefabricated ASN.1 constants
33 */
34 static u_char ASN1_INTEGER_0_str[] = { 0x02, 0x00 };
35 static u_char ASN1_INTEGER_1_str[] = { 0x02, 0x01, 0x01 };
36 static u_char ASN1_INTEGER_2_str[] = { 0x02, 0x01, 0x02 };
37
38 const chunk_t ASN1_INTEGER_0 = chunk_from_buf(ASN1_INTEGER_0_str);
39 const chunk_t ASN1_INTEGER_1 = chunk_from_buf(ASN1_INTEGER_1_str);
40 const chunk_t ASN1_INTEGER_2 = chunk_from_buf(ASN1_INTEGER_2_str);
41
42 /**
43 * some popular algorithmIdentifiers
44 */
45
46 static u_char ASN1_md2_id_str[] = {
47 0x30, 0x0c,
48 0x06, 0x08,
49 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x02,
50 0x05,0x00,
51 };
52
53 static u_char ASN1_md5_id_str[] = {
54 0x30, 0x0C,
55 0x06, 0x08,
56 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05,
57 0x05, 0x00
58 };
59
60 static u_char ASN1_sha1_id_str[] = {
61 0x30, 0x09,
62 0x06, 0x05,
63 0x2B, 0x0E,0x03, 0x02, 0x1A,
64 0x05, 0x00
65 };
66
67 static u_char ASN1_sha256_id_str[] = {
68 0x30, 0x0d,
69 0x06, 0x09,
70 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
71 0x05, 0x00
72 };
73
74 static u_char ASN1_sha384_id_str[] = {
75 0x30, 0x0d,
76 0x06, 0x09,
77 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
78 0x05, 0x00
79 };
80
81 static u_char ASN1_sha512_id_str[] = {
82 0x30, 0x0d,
83 0x06, 0x09,
84 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
85 0x05,0x00
86 };
87
88 static u_char ASN1_md2WithRSA_id_str[] = {
89 0x30, 0x0D,
90 0x06, 0x09,
91 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x02,
92 0x05, 0x00
93 };
94
95 static u_char ASN1_md5WithRSA_id_str[] = {
96 0x30, 0x0D,
97 0x06, 0x09,
98 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x04,
99 0x05, 0x00
100 };
101
102 static u_char ASN1_sha1WithRSA_id_str[] = {
103 0x30, 0x0D,
104 0x06, 0x09,
105 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x05,
106 0x05, 0x00
107 };
108
109 static u_char ASN1_sha256WithRSA_id_str[] = {
110 0x30, 0x0D,
111 0x06, 0x09,
112 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0B,
113 0x05, 0x00
114 };
115
116 static u_char ASN1_sha384WithRSA_id_str[] = {
117 0x30, 0x0D,
118 0x06, 0x09,
119 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0C,
120 0x05, 0x00
121 };
122
123 static u_char ASN1_sha512WithRSA_id_str[] = {
124 0x30, 0x0D,
125 0x06, 0x09,
126 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0D,
127 0x05, 0x00
128 };
129
130 static u_char ASN1_rsaEncryption_id_str[] = {
131 0x30, 0x0D,
132 0x06, 0x09,
133 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01,
134 0x05, 0x00
135 };
136
137 static const chunk_t ASN1_md2_id = chunk_from_buf(ASN1_md2_id_str);
138 static const chunk_t ASN1_md5_id = chunk_from_buf(ASN1_md5_id_str);
139 static const chunk_t ASN1_sha1_id = chunk_from_buf(ASN1_sha1_id_str);
140 static const chunk_t ASN1_sha256_id = chunk_from_buf(ASN1_sha256_id_str);
141 static const chunk_t ASN1_sha384_id = chunk_from_buf(ASN1_sha384_id_str);
142 static const chunk_t ASN1_sha512_id = chunk_from_buf(ASN1_sha512_id_str);
143 static const chunk_t ASN1_rsaEncryption_id = chunk_from_buf(ASN1_rsaEncryption_id_str);
144 static const chunk_t ASN1_md2WithRSA_id = chunk_from_buf(ASN1_md2WithRSA_id_str);
145 static const chunk_t ASN1_md5WithRSA_id = chunk_from_buf(ASN1_md5WithRSA_id_str);
146 static const chunk_t ASN1_sha1WithRSA_id = chunk_from_buf(ASN1_sha1WithRSA_id_str);
147 static const chunk_t ASN1_sha256WithRSA_id = chunk_from_buf(ASN1_sha256WithRSA_id_str);
148 static const chunk_t ASN1_sha384WithRSA_id = chunk_from_buf(ASN1_sha384WithRSA_id_str);
149 static const chunk_t ASN1_sha512WithRSA_id = chunk_from_buf(ASN1_sha512WithRSA_id_str);
150
151 /*
152 * Defined in header.
153 */
154 chunk_t asn1_algorithmIdentifier(int oid)
155 {
156 switch (oid)
157 {
158 case OID_RSA_ENCRYPTION:
159 return ASN1_rsaEncryption_id;
160 case OID_MD2_WITH_RSA:
161 return ASN1_md2WithRSA_id;
162 case OID_MD5_WITH_RSA:
163 return ASN1_md5WithRSA_id;
164 case OID_SHA1_WITH_RSA:
165 return ASN1_sha1WithRSA_id;
166 case OID_SHA256_WITH_RSA:
167 return ASN1_sha256WithRSA_id;
168 case OID_SHA384_WITH_RSA:
169 return ASN1_sha384WithRSA_id;
170 case OID_SHA512_WITH_RSA:
171 return ASN1_sha512WithRSA_id;
172 case OID_MD2:
173 return ASN1_md2_id;
174 case OID_MD5:
175 return ASN1_md5_id;
176 case OID_SHA1:
177 return ASN1_sha1_id;
178 case OID_SHA256:
179 return ASN1_sha256_id;
180 case OID_SHA384:
181 return ASN1_sha384_id;
182 case OID_SHA512:
183 return ASN1_sha512_id;
184 default:
185 return chunk_empty;
186 }
187 }
188
189 /*
190 * Defined in header.
191 */
192 int asn1_known_oid(chunk_t object)
193 {
194 int oid = 0;
195
196 while (object.len)
197 {
198 if (oid_names[oid].octet == *object.ptr)
199 {
200 if (--object.len == 0 || oid_names[oid].down == 0)
201 {
202 return oid; /* found terminal symbol */
203 }
204 else
205 {
206 object.ptr++; oid++; /* advance to next hex octet */
207 }
208 }
209 else
210 {
211 if (oid_names[oid].next)
212 oid = oid_names[oid].next;
213 else
214 return OID_UNKNOWN;
215 }
216 }
217 return -1;
218 }
219
220 /*
221 * Defined in header.
222 */
223 chunk_t asn1_get_known_oid(int n)
224 {
225 chunk_t oid;
226 int i;
227
228 if (n < 0 || n >= OID_MAX)
229 {
230 return chunk_empty;
231 }
232
233 i = oid_names[n].level + 1;
234 oid = chunk_alloc(i);
235 do
236 {
237 if (oid_names[n].level >= i)
238 {
239 n--;
240 continue;
241 }
242 oid.ptr[--i] = oid_names[n--].octet;
243 }
244 while (i > 0);
245
246 return oid;
247 }
248
249 /*
250 * Defined in header.
251 */
252 u_int asn1_length(chunk_t *blob)
253 {
254 u_char n;
255 size_t len;
256
257 /* advance from tag field on to length field */
258 blob->ptr++;
259 blob->len--;
260
261 /* read first octet of length field */
262 n = *blob->ptr++;
263 blob->len--;
264
265 if ((n & 0x80) == 0)
266 {/* single length octet */
267 return n;
268 }
269
270 /* composite length, determine number of length octets */
271 n &= 0x7f;
272
273 if (n > blob->len)
274 {
275 DBG2("number of length octets is larger than ASN.1 object");
276 return ASN1_INVALID_LENGTH;
277 }
278
279 if (n > sizeof(len))
280 {
281 DBG2("number of length octets is larger than limit of %d octets",
282 (int)sizeof(len));
283 return ASN1_INVALID_LENGTH;
284 }
285
286 len = 0;
287
288 while (n-- > 0)
289 {
290 len = 256*len + *blob->ptr++;
291 blob->len--;
292 }
293 return len;
294 }
295
296 #define TIME_MAX 0x7fffffff
297
298 /**
299 * Converts ASN.1 UTCTIME or GENERALIZEDTIME into calender time
300 */
301 time_t asn1_to_time(const chunk_t *utctime, asn1_t type)
302 {
303 struct tm t;
304 time_t tc, tz_offset;
305 u_char *eot = NULL;
306
307 if ((eot = memchr(utctime->ptr, 'Z', utctime->len)) != NULL)
308 {
309 tz_offset = 0; /* Zulu time with a zero time zone offset */
310 }
311 else if ((eot = memchr(utctime->ptr, '+', utctime->len)) != NULL)
312 {
313 int tz_hour, tz_min;
314
315 sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
316 tz_offset = 3600*tz_hour + 60*tz_min; /* positive time zone offset */
317 }
318 else if ((eot = memchr(utctime->ptr, '-', utctime->len)) != NULL)
319 {
320 int tz_hour, tz_min;
321
322 sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
323 tz_offset = -3600*tz_hour - 60*tz_min; /* negative time zone offset */
324 }
325 else
326 {
327 return 0; /* error in time format */
328 }
329
330 /* parse ASN.1 time string */
331 {
332 const char* format = (type == ASN1_UTCTIME)? "%2d%2d%2d%2d%2d":
333 "%4d%2d%2d%2d%2d";
334
335 sscanf(utctime->ptr, format, &t.tm_year, &t.tm_mon, &t.tm_mday,
336 &t.tm_hour, &t.tm_min);
337 }
338
339 /* is there a seconds field? */
340 if ((eot - utctime->ptr) == ((type == ASN1_UTCTIME)?12:14))
341 {
342 sscanf(eot-2, "%2d", &t.tm_sec);
343 }
344 else
345 {
346 t.tm_sec = 0;
347 }
348
349 /* representation of year */
350 if (t.tm_year >= 1900)
351 {
352 t.tm_year -= 1900;
353 }
354 else if (t.tm_year >= 100)
355 {
356 return 0;
357 }
358 else if (t.tm_year < 50)
359 {
360 t.tm_year += 100;
361 }
362
363 /* representation of month 0..11*/
364 t.tm_mon--;
365
366 /* set daylight saving time to off */
367 t.tm_isdst = 0;
368
369 /* convert to time_t */
370 tc = mktime(&t);
371
372 /* if no conversion overflow occurred, compensate timezone */
373 return (tc == -1) ? TIME_MAX : (tc - timezone - tz_offset);
374 }
375
376 /**
377 * Convert a date into ASN.1 UTCTIME or GENERALIZEDTIME format
378 */
379 chunk_t asn1_from_time(const time_t *time, asn1_t type)
380 {
381 int offset;
382 const char *format;
383 char buf[BUF_LEN];
384 chunk_t formatted_time;
385 struct tm t;
386
387 gmtime_r(time, &t);
388 if (type == ASN1_GENERALIZEDTIME)
389 {
390 format = "%04d%02d%02d%02d%02d%02dZ";
391 offset = 1900;
392 }
393 else /* ASN1_UTCTIME */
394 {
395 format = "%02d%02d%02d%02d%02d%02dZ";
396 offset = (t.tm_year < 100)? 0 : -100;
397 }
398 snprintf(buf, BUF_LEN, format, t.tm_year + offset,
399 t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec);
400 formatted_time.ptr = buf;
401 formatted_time.len = strlen(buf);
402 return asn1_simple_object(type, formatted_time);
403 }
404
405 /*
406 * Defined in header.
407 */
408 void asn1_debug_simple_object(chunk_t object, asn1_t type, bool private)
409 {
410 int oid;
411
412 switch (type)
413 {
414 case ASN1_OID:
415 oid = asn1_known_oid(object);
416 if (oid != OID_UNKNOWN)
417 {
418 DBG2(" '%s'", oid_names[oid].name);
419 return;
420 }
421 break;
422 case ASN1_UTF8STRING:
423 case ASN1_IA5STRING:
424 case ASN1_PRINTABLESTRING:
425 case ASN1_T61STRING:
426 case ASN1_VISIBLESTRING:
427 DBG2(" '%.*s'", (int)object.len, object.ptr);
428 return;
429 case ASN1_UTCTIME:
430 case ASN1_GENERALIZEDTIME:
431 {
432 time_t time = asn1_to_time(&object, type);
433
434 DBG2(" '%T'", &time, TRUE);
435 }
436 return;
437 default:
438 break;
439 }
440 if (private)
441 {
442 DBG4("%B", &object);
443 }
444 else
445 {
446 DBG3("%B", &object);
447 }
448 }
449
450 /**
451 * parse an ASN.1 simple type
452 */
453 bool asn1_parse_simple_object(chunk_t *object, asn1_t type, u_int level, const char* name)
454 {
455 size_t len;
456
457 /* an ASN.1 object must possess at least a tag and length field */
458 if (object->len < 2)
459 {
460 DBG2("L%d - %s: ASN.1 object smaller than 2 octets", level, name);
461 return FALSE;
462 }
463
464 if (*object->ptr != type)
465 {
466 DBG2("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
467 level, name, type, *object->ptr);
468 return FALSE;
469 }
470
471 len = asn1_length(object);
472
473 if (len == ASN1_INVALID_LENGTH || object->len < len)
474 {
475 DBG2("L%d - %s: length of ASN.1 object invalid or too large",
476 level, name);
477 return FALSE;
478 }
479
480 DBG2("L%d - %s:", level, name);
481 asn1_debug_simple_object(*object, type, FALSE);
482 return TRUE;
483 }
484
485 /**
486 * ASN.1 definition of an algorithmIdentifier
487 */
488 static const asn1Object_t algorithmIdentifierObjects[] = {
489 { 0, "algorithmIdentifier", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
490 { 1, "algorithm", ASN1_OID, ASN1_BODY }, /* 1 */
491 { 1, "parameters", ASN1_EOC, ASN1_RAW|ASN1_OPT }, /* 2 */
492 { 1, "end opt", ASN1_EOC, ASN1_END }, /* 3 */
493 { 0, "exit", ASN1_EOC, ASN1_EXIT }
494 };
495 #define ALGORITHM_ID_ALG 1
496 #define ALGORITHM_ID_PARAMETERS 2
497
498 /*
499 * Defined in header
500 */
501 int asn1_parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
502 {
503 asn1_parser_t *parser;
504 chunk_t object;
505 int objectID;
506 int alg = OID_UNKNOWN;
507
508 parser = asn1_parser_create(algorithmIdentifierObjects, blob);
509 parser->set_top_level(parser, level0);
510
511 while (parser->iterate(parser, &objectID, &object))
512 {
513 switch (objectID)
514 {
515 case ALGORITHM_ID_ALG:
516 alg = asn1_known_oid(object);
517 break;
518 case ALGORITHM_ID_PARAMETERS:
519 if (parameters != NULL)
520 {
521 *parameters = object;
522 }
523 break;
524 default:
525 break;
526 }
527 }
528 parser->destroy(parser);
529 return alg;
530 }
531
532 /*
533 * tests if a blob contains a valid ASN.1 set or sequence
534 */
535 bool is_asn1(chunk_t blob)
536 {
537 u_int len;
538 u_char tag = *blob.ptr;
539
540 if (tag != ASN1_SEQUENCE && tag != ASN1_SET)
541 {
542 DBG2(" file content is not binary ASN.1");
543 return FALSE;
544 }
545
546 len = asn1_length(&blob);
547
548 /* exact match */
549 if (len == blob.len)
550 {
551 return TRUE;
552 }
553
554 /* some websites append a surplus newline character to the blob */
555 if (len + 1 == blob.len && *(blob.ptr + len) == '\n')
556 {
557 return TRUE;
558 }
559
560 DBG2(" file size does not match ASN.1 coded length");
561 return FALSE;
562 }
563
564 /*
565 * Defined in header.
566 */
567 bool asn1_is_printablestring(chunk_t str)
568 {
569 const char printablestring_charset[] =
570 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 '()+,-./:=?";
571 u_int i;
572
573 for (i = 0; i < str.len; i++)
574 {
575 if (strchr(printablestring_charset, str.ptr[i]) == NULL)
576 return FALSE;
577 }
578 return TRUE;
579 }
580
581 /**
582 * codes ASN.1 lengths up to a size of 16'777'215 bytes
583 */
584 static void asn1_code_length(size_t length, chunk_t *code)
585 {
586 if (length < 128)
587 {
588 code->ptr[0] = length;
589 code->len = 1;
590 }
591 else if (length < 256)
592 {
593 code->ptr[0] = 0x81;
594 code->ptr[1] = (u_char) length;
595 code->len = 2;
596 }
597 else if (length < 65536)
598 {
599 code->ptr[0] = 0x82;
600 code->ptr[1] = length >> 8;
601 code->ptr[2] = length & 0x00ff;
602 code->len = 3;
603 }
604 else
605 {
606 code->ptr[0] = 0x83;
607 code->ptr[1] = length >> 16;
608 code->ptr[2] = (length >> 8) & 0x00ff;
609 code->ptr[3] = length & 0x0000ff;
610 code->len = 4;
611 }
612 }
613
614 /**
615 * build an empty asn.1 object with tag and length fields already filled in
616 */
617 u_char* asn1_build_object(chunk_t *object, asn1_t type, size_t datalen)
618 {
619 u_char length_buf[4];
620 chunk_t length = { length_buf, 0 };
621 u_char *pos;
622
623 /* code the asn.1 length field */
624 asn1_code_length(datalen, &length);
625
626 /* allocate memory for the asn.1 TLV object */
627 object->len = 1 + length.len + datalen;
628 object->ptr = malloc(object->len);
629
630 /* set position pointer at the start of the object */
631 pos = object->ptr;
632
633 /* copy the asn.1 tag field and advance the pointer */
634 *pos++ = type;
635
636 /* copy the asn.1 length field and advance the pointer */
637 memcpy(pos, length.ptr, length.len);
638 pos += length.len;
639
640 return pos;
641 }
642
643 /**
644 * Build a simple ASN.1 object
645 */
646 chunk_t asn1_simple_object(asn1_t tag, chunk_t content)
647 {
648 chunk_t object;
649
650 u_char *pos = asn1_build_object(&object, tag, content.len);
651 memcpy(pos, content.ptr, content.len);
652 pos += content.len;
653
654 return object;
655 }
656
657 /**
658 * Build an ASN.1 BITSTRING object
659 */
660 chunk_t asn1_bitstring(const char *mode, chunk_t content)
661 {
662 chunk_t object;
663 u_char *pos = asn1_build_object(&object, ASN1_BIT_STRING, 1 + content.len);
664
665 *pos++ = 0x00;
666 memcpy(pos, content.ptr, content.len);
667 if (*mode == 'm')
668 {
669 free(content.ptr);
670 }
671 return object;
672 }
673
674 /**
675 * Build an ASN.1 object from a variable number of individual chunks.
676 * Depending on the mode, chunks either are moved ('m') or copied ('c').
677 */
678 chunk_t asn1_wrap(asn1_t type, const char *mode, ...)
679 {
680 chunk_t construct;
681 va_list chunks;
682 u_char *pos;
683 int i;
684 int count = strlen(mode);
685
686 /* sum up lengths of individual chunks */
687 va_start(chunks, mode);
688 construct.len = 0;
689 for (i = 0; i < count; i++)
690 {
691 chunk_t ch = va_arg(chunks, chunk_t);
692 construct.len += ch.len;
693 }
694 va_end(chunks);
695
696 /* allocate needed memory for construct */
697 pos = asn1_build_object(&construct, type, construct.len);
698
699 /* copy or move the chunks */
700 va_start(chunks, mode);
701 for (i = 0; i < count; i++)
702 {
703 chunk_t ch = va_arg(chunks, chunk_t);
704
705 memcpy(pos, ch.ptr, ch.len);
706 pos += ch.len;
707
708 if (*mode++ == 'm')
709 {
710 free(ch.ptr);
711 }
712 }
713 va_end(chunks);
714
715 return construct;
716 }
717
718 /**
719 * ASN.1 definition of time
720 */
721 static const asn1Object_t timeObjects[] = {
722 { 0, "utcTime", ASN1_UTCTIME, ASN1_OPT|ASN1_BODY }, /* 0 */
723 { 0, "end opt", ASN1_EOC, ASN1_END }, /* 1 */
724 { 0, "generalizeTime", ASN1_GENERALIZEDTIME, ASN1_OPT|ASN1_BODY }, /* 2 */
725 { 0, "end opt", ASN1_EOC, ASN1_END }, /* 3 */
726 { 0, "exit", ASN1_EOC, ASN1_EXIT }
727 };
728 #define TIME_UTC 0
729 #define TIME_GENERALIZED 2
730
731 /**
732 * extracts and converts a UTCTIME or GENERALIZEDTIME object
733 */
734 time_t asn1_parse_time(chunk_t blob, int level0)
735 {
736 asn1_parser_t *parser;
737 chunk_t object;
738 int objectID;
739 time_t utc_time = 0;
740
741 parser= asn1_parser_create(timeObjects, blob);
742 parser->set_top_level(parser, level0);
743
744 while (parser->iterate(parser, &objectID, &object))
745 {
746 if (objectID == TIME_UTC || objectID == TIME_GENERALIZED)
747 {
748 utc_time = asn1_to_time(&object, (objectID == TIME_UTC)
749 ? ASN1_UTCTIME : ASN1_GENERALIZEDTIME);
750 }
751 }
752 parser->destroy(parser);
753 return utc_time;
754 }