fixed ASN.1 to time_t conversion on 32-bit system for dates after Jan 19 03:14:07...
[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 u_int asn1_length(chunk_t *blob)
224 {
225 u_char n;
226 size_t len;
227
228 /* advance from tag field on to length field */
229 blob->ptr++;
230 blob->len--;
231
232 /* read first octet of length field */
233 n = *blob->ptr++;
234 blob->len--;
235
236 if ((n & 0x80) == 0)
237 {/* single length octet */
238 return n;
239 }
240
241 /* composite length, determine number of length octets */
242 n &= 0x7f;
243
244 if (n > blob->len)
245 {
246 DBG2("number of length octets is larger than ASN.1 object");
247 return ASN1_INVALID_LENGTH;
248 }
249
250 if (n > sizeof(len))
251 {
252 DBG2("number of length octets is larger than limit of %d octets",
253 (int)sizeof(len));
254 return ASN1_INVALID_LENGTH;
255 }
256
257 len = 0;
258
259 while (n-- > 0)
260 {
261 len = 256*len + *blob->ptr++;
262 blob->len--;
263 }
264 return len;
265 }
266
267 #define TIME_MAX 0x7fffffff
268
269 /**
270 * Converts ASN.1 UTCTIME or GENERALIZEDTIME into calender time
271 */
272 time_t asn1_to_time(const chunk_t *utctime, asn1_t type)
273 {
274 struct tm t;
275 time_t tc, tz_offset;
276 u_char *eot = NULL;
277
278 if ((eot = memchr(utctime->ptr, 'Z', utctime->len)) != NULL)
279 {
280 tz_offset = 0; /* Zulu time with a zero time zone offset */
281 }
282 else if ((eot = memchr(utctime->ptr, '+', utctime->len)) != NULL)
283 {
284 int tz_hour, tz_min;
285
286 sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
287 tz_offset = 3600*tz_hour + 60*tz_min; /* positive time zone offset */
288 }
289 else if ((eot = memchr(utctime->ptr, '-', utctime->len)) != NULL)
290 {
291 int tz_hour, tz_min;
292
293 sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
294 tz_offset = -3600*tz_hour - 60*tz_min; /* negative time zone offset */
295 }
296 else
297 {
298 return 0; /* error in time format */
299 }
300
301 /* parse ASN.1 time string */
302 {
303 const char* format = (type == ASN1_UTCTIME)? "%2d%2d%2d%2d%2d":
304 "%4d%2d%2d%2d%2d";
305
306 sscanf(utctime->ptr, format, &t.tm_year, &t.tm_mon, &t.tm_mday,
307 &t.tm_hour, &t.tm_min);
308 }
309
310 /* is there a seconds field? */
311 if ((eot - utctime->ptr) == ((type == ASN1_UTCTIME)?12:14))
312 {
313 sscanf(eot-2, "%2d", &t.tm_sec);
314 }
315 else
316 {
317 t.tm_sec = 0;
318 }
319
320 /* representation of year */
321 if (t.tm_year >= 1900)
322 {
323 t.tm_year -= 1900;
324 }
325 else if (t.tm_year >= 100)
326 {
327 return 0;
328 }
329 else if (t.tm_year < 50)
330 {
331 t.tm_year += 100;
332 }
333
334 /* representation of month 0..11*/
335 t.tm_mon--;
336
337 /* set daylight saving time to off */
338 t.tm_isdst = 0;
339
340 /* convert to time_t */
341 tc = mktime(&t);
342
343 /* if no conversion overflow occurred, compensate timezone */
344 return (tc == -1) ? TIME_MAX : tc - timezone - tz_offset;
345 }
346
347 /**
348 * Convert a date into ASN.1 UTCTIME or GENERALIZEDTIME format
349 */
350 chunk_t asn1_from_time(const time_t *time, asn1_t type)
351 {
352 int offset;
353 const char *format;
354 char buf[BUF_LEN];
355 chunk_t formatted_time;
356 struct tm t;
357
358 gmtime_r(time, &t);
359 if (type == ASN1_GENERALIZEDTIME)
360 {
361 format = "%04d%02d%02d%02d%02d%02dZ";
362 offset = 1900;
363 }
364 else /* ASN1_UTCTIME */
365 {
366 format = "%02d%02d%02d%02d%02d%02dZ";
367 offset = (t.tm_year < 100)? 0 : -100;
368 }
369 snprintf(buf, BUF_LEN, format, t.tm_year + offset,
370 t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec);
371 formatted_time.ptr = buf;
372 formatted_time.len = strlen(buf);
373 return asn1_simple_object(type, formatted_time);
374 }
375
376 /*
377 * Defined in header.
378 */
379 void asn1_debug_simple_object(chunk_t object, asn1_t type, bool private)
380 {
381 int oid;
382
383 switch (type)
384 {
385 case ASN1_OID:
386 oid = asn1_known_oid(object);
387 if (oid != OID_UNKNOWN)
388 {
389 DBG2(" '%s'", oid_names[oid].name);
390 return;
391 }
392 break;
393 case ASN1_UTF8STRING:
394 case ASN1_IA5STRING:
395 case ASN1_PRINTABLESTRING:
396 case ASN1_T61STRING:
397 case ASN1_VISIBLESTRING:
398 DBG2(" '%.*s'", (int)object.len, object.ptr);
399 return;
400 case ASN1_UTCTIME:
401 case ASN1_GENERALIZEDTIME:
402 {
403 time_t time = asn1_to_time(&object, type);
404
405 DBG2(" '%T'", &time, TRUE);
406 }
407 return;
408 default:
409 break;
410 }
411 if (private)
412 {
413 DBG4("%B", &object);
414 }
415 else
416 {
417 DBG3("%B", &object);
418 }
419 }
420
421 /**
422 * parse an ASN.1 simple type
423 */
424 bool asn1_parse_simple_object(chunk_t *object, asn1_t type, u_int level, const char* name)
425 {
426 size_t len;
427
428 /* an ASN.1 object must possess at least a tag and length field */
429 if (object->len < 2)
430 {
431 DBG2("L%d - %s: ASN.1 object smaller than 2 octets", level, name);
432 return FALSE;
433 }
434
435 if (*object->ptr != type)
436 {
437 DBG2("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
438 level, name, type, *object->ptr);
439 return FALSE;
440 }
441
442 len = asn1_length(object);
443
444 if (len == ASN1_INVALID_LENGTH || object->len < len)
445 {
446 DBG2("L%d - %s: length of ASN.1 object invalid or too large",
447 level, name);
448 return FALSE;
449 }
450
451 DBG2("L%d - %s:", level, name);
452 asn1_debug_simple_object(*object, type, FALSE);
453 return TRUE;
454 }
455
456 /**
457 * ASN.1 definition of an algorithmIdentifier
458 */
459 static const asn1Object_t algorithmIdentifierObjects[] = {
460 { 0, "algorithmIdentifier", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
461 { 1, "algorithm", ASN1_OID, ASN1_BODY }, /* 1 */
462 { 1, "parameters", ASN1_EOC, ASN1_RAW|ASN1_OPT }, /* 2 */
463 { 1, "end opt", ASN1_EOC, ASN1_END }, /* 3 */
464 { 0, "exit", ASN1_EOC, ASN1_EXIT }
465 };
466 #define ALGORITHM_ID_ALG 1
467 #define ALGORITHM_ID_PARAMETERS 2
468
469 /*
470 * Defined in header
471 */
472 int asn1_parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
473 {
474 asn1_parser_t *parser;
475 chunk_t object;
476 int objectID;
477 int alg = OID_UNKNOWN;
478
479 parser = asn1_parser_create(algorithmIdentifierObjects, blob);
480 parser->set_top_level(parser, level0);
481
482 while (parser->iterate(parser, &objectID, &object))
483 {
484 switch (objectID)
485 {
486 case ALGORITHM_ID_ALG:
487 alg = asn1_known_oid(object);
488 break;
489 case ALGORITHM_ID_PARAMETERS:
490 if (parameters != NULL)
491 {
492 *parameters = object;
493 }
494 break;
495 default:
496 break;
497 }
498 }
499 parser->destroy(parser);
500 return alg;
501 }
502
503 /*
504 * tests if a blob contains a valid ASN.1 set or sequence
505 */
506 bool is_asn1(chunk_t blob)
507 {
508 u_int len;
509 u_char tag = *blob.ptr;
510
511 if (tag != ASN1_SEQUENCE && tag != ASN1_SET)
512 {
513 DBG2(" file content is not binary ASN.1");
514 return FALSE;
515 }
516
517 len = asn1_length(&blob);
518
519 /* exact match */
520 if (len == blob.len)
521 {
522 return TRUE;
523 }
524
525 /* some websites append a surplus newline character to the blob */
526 if (len + 1 == blob.len && *(blob.ptr + len) == '\n')
527 {
528 return TRUE;
529 }
530
531 DBG2(" file size does not match ASN.1 coded length");
532 return FALSE;
533 }
534
535 /*
536 * Defined in header.
537 */
538 bool asn1_is_printablestring(chunk_t str)
539 {
540 const char printablestring_charset[] =
541 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 '()+,-./:=?";
542 u_int i;
543
544 for (i = 0; i < str.len; i++)
545 {
546 if (strchr(printablestring_charset, str.ptr[i]) == NULL)
547 return FALSE;
548 }
549 return TRUE;
550 }
551
552 /**
553 * codes ASN.1 lengths up to a size of 16'777'215 bytes
554 */
555 static void asn1_code_length(size_t length, chunk_t *code)
556 {
557 if (length < 128)
558 {
559 code->ptr[0] = length;
560 code->len = 1;
561 }
562 else if (length < 256)
563 {
564 code->ptr[0] = 0x81;
565 code->ptr[1] = (u_char) length;
566 code->len = 2;
567 }
568 else if (length < 65536)
569 {
570 code->ptr[0] = 0x82;
571 code->ptr[1] = length >> 8;
572 code->ptr[2] = length & 0x00ff;
573 code->len = 3;
574 }
575 else
576 {
577 code->ptr[0] = 0x83;
578 code->ptr[1] = length >> 16;
579 code->ptr[2] = (length >> 8) & 0x00ff;
580 code->ptr[3] = length & 0x0000ff;
581 code->len = 4;
582 }
583 }
584
585 /**
586 * build an empty asn.1 object with tag and length fields already filled in
587 */
588 u_char* asn1_build_object(chunk_t *object, asn1_t type, size_t datalen)
589 {
590 u_char length_buf[4];
591 chunk_t length = { length_buf, 0 };
592 u_char *pos;
593
594 /* code the asn.1 length field */
595 asn1_code_length(datalen, &length);
596
597 /* allocate memory for the asn.1 TLV object */
598 object->len = 1 + length.len + datalen;
599 object->ptr = malloc(object->len);
600
601 /* set position pointer at the start of the object */
602 pos = object->ptr;
603
604 /* copy the asn.1 tag field and advance the pointer */
605 *pos++ = type;
606
607 /* copy the asn.1 length field and advance the pointer */
608 memcpy(pos, length.ptr, length.len);
609 pos += length.len;
610
611 return pos;
612 }
613
614 /**
615 * Build a simple ASN.1 object
616 */
617 chunk_t asn1_simple_object(asn1_t tag, chunk_t content)
618 {
619 chunk_t object;
620
621 u_char *pos = asn1_build_object(&object, tag, content.len);
622 memcpy(pos, content.ptr, content.len);
623 pos += content.len;
624
625 return object;
626 }
627
628 /**
629 * Build an ASN.1 BITSTRING object
630 */
631 chunk_t asn1_bitstring(const char *mode, chunk_t content)
632 {
633 chunk_t object;
634 u_char *pos = asn1_build_object(&object, ASN1_BIT_STRING, 1 + content.len);
635
636 *pos++ = 0x00;
637 memcpy(pos, content.ptr, content.len);
638 if (*mode == 'm')
639 {
640 free(content.ptr);
641 }
642 return object;
643 }
644
645 /**
646 * Build an ASN.1 object from a variable number of individual chunks.
647 * Depending on the mode, chunks either are moved ('m') or copied ('c').
648 */
649 chunk_t asn1_wrap(asn1_t type, const char *mode, ...)
650 {
651 chunk_t construct;
652 va_list chunks;
653 u_char *pos;
654 int i;
655 int count = strlen(mode);
656
657 /* sum up lengths of individual chunks */
658 va_start(chunks, mode);
659 construct.len = 0;
660 for (i = 0; i < count; i++)
661 {
662 chunk_t ch = va_arg(chunks, chunk_t);
663 construct.len += ch.len;
664 }
665 va_end(chunks);
666
667 /* allocate needed memory for construct */
668 pos = asn1_build_object(&construct, type, construct.len);
669
670 /* copy or move the chunks */
671 va_start(chunks, mode);
672 for (i = 0; i < count; i++)
673 {
674 chunk_t ch = va_arg(chunks, chunk_t);
675
676 memcpy(pos, ch.ptr, ch.len);
677 pos += ch.len;
678
679 if (*mode++ == 'm')
680 {
681 free(ch.ptr);
682 }
683 }
684 va_end(chunks);
685
686 return construct;
687 }
688
689 /**
690 * ASN.1 definition of time
691 */
692 static const asn1Object_t timeObjects[] = {
693 { 0, "utcTime", ASN1_UTCTIME, ASN1_OPT|ASN1_BODY }, /* 0 */
694 { 0, "end opt", ASN1_EOC, ASN1_END }, /* 1 */
695 { 0, "generalizeTime", ASN1_GENERALIZEDTIME, ASN1_OPT|ASN1_BODY }, /* 2 */
696 { 0, "end opt", ASN1_EOC, ASN1_END }, /* 3 */
697 { 0, "exit", ASN1_EOC, ASN1_EXIT }
698 };
699 #define TIME_UTC 0
700 #define TIME_GENERALIZED 2
701
702 /**
703 * extracts and converts a UTCTIME or GENERALIZEDTIME object
704 */
705 time_t asn1_parse_time(chunk_t blob, int level0)
706 {
707 asn1_parser_t *parser;
708 chunk_t object;
709 int objectID;
710 time_t utc_time = 0;
711
712 parser= asn1_parser_create(timeObjects, blob);
713 parser->set_top_level(parser, level0);
714
715 while (parser->iterate(parser, &objectID, &object))
716 {
717 if (objectID == TIME_UTC || objectID == TIME_GENERALIZED)
718 {
719 utc_time = asn1_to_time(&object, (objectID == TIME_UTC)
720 ? ASN1_UTCTIME : ASN1_GENERALIZEDTIME);
721 }
722 }
723 parser->destroy(parser);
724 return utc_time;
725 }