1/*
2 * Copyright (c) 1997 - 2007 Kungliga Tekniska H��gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "der_locl.h"
35
36/*
37 * All decoding functions take a pointer `p' to first position in
38 * which to read, from the left, `len' which means the maximum number
39 * of characters we are able to read, `ret' were the value will be
40 * returned and `size' where the number of used bytes is stored.
41 * Either 0 or an error code is returned.
42 */
43
44int
45der_get_unsigned (const unsigned char *p, size_t len,
46		  unsigned *ret, size_t *size)
47{
48    unsigned val = 0;
49    size_t oldlen = len;
50
51    if (len == sizeof(val) + 1 && p[0] == 0)
52	;
53    else if (len > sizeof(val))
54	return ASN1_OVERRUN;
55
56    while (len--)
57	val = val * 256 + *p++;
58    *ret = val;
59    if(size) *size = oldlen;
60    return 0;
61}
62
63int
64der_get_unsigned64 (const unsigned char *p, size_t len,
65		    uint64_t *ret, size_t *size)
66{
67    uint64_t val = 0;
68    size_t oldlen = len;
69
70    if (len == sizeof(val) + 1 && p[0] == 0)
71	;
72    else if (len > sizeof(val))
73	return ASN1_OVERRUN;
74
75    while (len--)
76	val = val * 256 + *p++;
77    *ret = val;
78    if(size) *size = oldlen;
79    return 0;
80}
81
82int
83der_get_integer (const unsigned char *p, size_t len,
84		 int *ret, size_t *size)
85{
86    int val = 0;
87    size_t oldlen = len;
88
89    if (len > sizeof(val))
90	return ASN1_OVERRUN;
91
92    if (len > 0) {
93	val = (signed char)*p++;
94	while (--len)
95	    val = val * 256 + *p++;
96    }
97    *ret = val;
98    if(size) *size = oldlen;
99    return 0;
100}
101
102int
103der_get_integer64 (const unsigned char *p, size_t len,
104		   int64_t *ret, size_t *size)
105{
106    int64_t val = 0;
107    size_t oldlen = len;
108
109    if (len > sizeof(val))
110	return ASN1_OVERRUN;
111
112    if (len > 0) {
113	val = (signed char)*p++;
114	while (--len)
115	    val = val * 256 + *p++;
116    }
117    *ret = val;
118    if(size) *size = oldlen;
119    return 0;
120}
121
122int
123der_get_length (const unsigned char *p, size_t len,
124		size_t *val, size_t *size)
125{
126    size_t v;
127
128    if (len <= 0)
129	return ASN1_OVERRUN;
130    --len;
131    v = *p++;
132    if (v < 128) {
133	*val = v;
134	if(size) *size = 1;
135    } else {
136	int e;
137	size_t l;
138	unsigned tmp;
139
140	if(v == 0x80){
141	    *val = ASN1_INDEFINITE;
142	    if(size) *size = 1;
143	    return 0;
144	}
145	v &= 0x7F;
146	if (len < v)
147	    return ASN1_OVERRUN;
148	e = der_get_unsigned (p, v, &tmp, &l);
149	if(e) return e;
150	*val = tmp;
151	if(size) *size = l + 1;
152    }
153    return 0;
154}
155
156int
157der_get_boolean(const unsigned char *p, size_t len, int *data, size_t *size)
158{
159    if(len < 1)
160	return ASN1_OVERRUN;
161    if(*p != 0)
162	*data = 1;
163    else
164	*data = 0;
165    *size = 1;
166    return 0;
167}
168
169int
170der_get_general_string (const unsigned char *p, size_t len,
171			heim_general_string *str, size_t *size)
172{
173    const unsigned char *p1;
174    char *s;
175
176    p1 = memchr(p, 0, len);
177    if (p1 != NULL) {
178	/*
179	 * Allow trailing NULs. We allow this since MIT Kerberos sends
180	 * an strings in the NEED_PREAUTH case that includes a
181	 * trailing NUL.
182	 */
183	while ((size_t)(p1 - p) < len && *p1 == '\0')
184	    p1++;
185       if ((size_t)(p1 - p) != len)
186	    return ASN1_BAD_CHARACTER;
187    }
188    if (len > len + 1)
189	return ASN1_BAD_LENGTH;
190
191    s = malloc (len + 1);
192    if (s == NULL)
193	return ENOMEM;
194    memcpy (s, p, len);
195    s[len] = '\0';
196    *str = s;
197    if(size) *size = len;
198    return 0;
199}
200
201int
202der_get_utf8string (const unsigned char *p, size_t len,
203		    heim_utf8_string *str, size_t *size)
204{
205    return der_get_general_string(p, len, str, size);
206}
207
208int
209der_get_printable_string(const unsigned char *p, size_t len,
210			 heim_printable_string *str, size_t *size)
211{
212    str->length = len;
213    str->data = malloc(len + 1);
214    if (str->data == NULL)
215	return ENOMEM;
216    memcpy(str->data, p, len);
217    ((char *)str->data)[len] = '\0';
218    if(size) *size = len;
219    return 0;
220}
221
222int
223der_get_ia5_string(const unsigned char *p, size_t len,
224		   heim_ia5_string *str, size_t *size)
225{
226    return der_get_printable_string(p, len, str, size);
227}
228
229int
230der_get_bmp_string (const unsigned char *p, size_t len,
231		    heim_bmp_string *data, size_t *size)
232{
233    size_t i;
234
235    if (len & 1)
236	return ASN1_BAD_FORMAT;
237    data->length = len / 2;
238    if (data->length > UINT_MAX/sizeof(data->data[0]))
239	return ERANGE;
240    data->data = malloc(data->length * sizeof(data->data[0]));
241    if (data->data == NULL && data->length != 0)
242	return ENOMEM;
243
244    for (i = 0; i < data->length; i++) {
245	data->data[i] = (p[0] << 8) | p[1];
246	p += 2;
247	/* check for NUL in the middle of the string */
248	if (data->data[i] == 0 && i != (data->length - 1)) {
249	    free(data->data);
250	    data->data = NULL;
251	    data->length = 0;
252	    return ASN1_BAD_CHARACTER;
253	}
254    }
255    if (size) *size = len;
256
257    return 0;
258}
259
260int
261der_get_universal_string (const unsigned char *p, size_t len,
262			  heim_universal_string *data, size_t *size)
263{
264    size_t i;
265
266    if (len & 3)
267	return ASN1_BAD_FORMAT;
268    data->length = len / 4;
269    if (data->length > UINT_MAX/sizeof(data->data[0]))
270	return ERANGE;
271    data->data = malloc(data->length * sizeof(data->data[0]));
272    if (data->data == NULL && data->length != 0)
273	return ENOMEM;
274
275    for (i = 0; i < data->length; i++) {
276	data->data[i] = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
277	p += 4;
278	/* check for NUL in the middle of the string */
279	if (data->data[i] == 0 && i != (data->length - 1)) {
280	    free(data->data);
281	    data->data = NULL;
282	    data->length = 0;
283	    return ASN1_BAD_CHARACTER;
284	}
285    }
286    if (size) *size = len;
287    return 0;
288}
289
290int
291der_get_visible_string (const unsigned char *p, size_t len,
292			heim_visible_string *str, size_t *size)
293{
294    return der_get_general_string(p, len, str, size);
295}
296
297int
298der_get_octet_string (const unsigned char *p, size_t len,
299		      heim_octet_string *data, size_t *size)
300{
301    data->length = len;
302    data->data = malloc(len);
303    if (data->data == NULL && data->length != 0)
304	return ENOMEM;
305    memcpy (data->data, p, len);
306    if(size) *size = len;
307    return 0;
308}
309
310int
311der_get_octet_string_ber (const unsigned char *p, size_t len,
312			  heim_octet_string *data, size_t *size)
313{
314    int e;
315    Der_type type;
316    Der_class class;
317    unsigned int tag, depth = 0;
318    size_t l, datalen, oldlen = len;
319
320    data->length = 0;
321    data->data = NULL;
322
323    while (len) {
324	e = der_get_tag (p, len, &class, &type, &tag, &l);
325	if (e) goto out;
326	if (class != ASN1_C_UNIV) {
327	    e = ASN1_BAD_ID;
328	    goto out;
329	}
330	if (type == PRIM && tag == UT_EndOfContent) {
331	    if (depth == 0)
332		break;
333	    depth--;
334	}
335	if (tag != UT_OctetString) {
336	    e = ASN1_BAD_ID;
337	    goto out;
338	}
339
340	p += l;
341	len -= l;
342	e = der_get_length (p, len, &datalen, &l);
343	if (e) goto out;
344	p += l;
345	len -= l;
346
347	if (datalen > len)
348	    return ASN1_OVERRUN;
349
350	if (type == PRIM) {
351	    void *ptr;
352
353	    ptr = realloc(data->data, data->length + datalen);
354	    if (ptr == NULL) {
355		e = ENOMEM;
356		goto out;
357	    }
358	    data->data = ptr;
359	    memcpy(((unsigned char *)data->data) + data->length, p, datalen);
360	    data->length += datalen;
361	} else
362	    depth++;
363
364	p += datalen;
365	len -= datalen;
366    }
367    if (depth != 0)
368	return ASN1_INDEF_OVERRUN;
369    if(size) *size = oldlen - len;
370    return 0;
371 out:
372    free(data->data);
373    data->data = NULL;
374    data->length = 0;
375    return e;
376}
377
378
379int
380der_get_heim_integer (const unsigned char *p, size_t len,
381		      heim_integer *data, size_t *size)
382{
383    data->length = 0;
384    data->negative = 0;
385    data->data = NULL;
386
387    if (len == 0) {
388	if (size)
389	    *size = 0;
390	return 0;
391    }
392    if (p[0] & 0x80) {
393	unsigned char *q;
394	int carry = 1;
395	data->negative = 1;
396
397	data->length = len;
398
399	if (p[0] == 0xff) {
400	    p++;
401	    data->length--;
402	}
403	data->data = malloc(data->length);
404	if (data->data == NULL) {
405	    data->length = 0;
406	    if (size)
407		*size = 0;
408	    return ENOMEM;
409	}
410	q = &((unsigned char*)data->data)[data->length - 1];
411	p += data->length - 1;
412	while (q >= (unsigned char*)data->data) {
413	    *q = *p ^ 0xff;
414	    if (carry)
415		carry = !++*q;
416	    p--;
417	    q--;
418	}
419    } else {
420	data->negative = 0;
421	data->length = len;
422
423	if (p[0] == 0) {
424	    p++;
425	    data->length--;
426	}
427	data->data = malloc(data->length);
428	if (data->data == NULL && data->length != 0) {
429	    data->length = 0;
430	    if (size)
431		*size = 0;
432	    return ENOMEM;
433	}
434	memcpy(data->data, p, data->length);
435    }
436    if (size)
437	*size = len;
438    return 0;
439}
440
441static int
442generalizedtime2time (const char *s, time_t *t)
443{
444    struct tm tm;
445
446    memset(&tm, 0, sizeof(tm));
447    if (sscanf (s, "%04d%02d%02d%02d%02d%02dZ",
448		&tm.tm_year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour,
449		&tm.tm_min, &tm.tm_sec) != 6) {
450	if (sscanf (s, "%02d%02d%02d%02d%02d%02dZ",
451		    &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour,
452		    &tm.tm_min, &tm.tm_sec) != 6)
453	    return ASN1_BAD_TIMEFORMAT;
454	if (tm.tm_year < 50)
455	    tm.tm_year += 2000;
456	else
457	    tm.tm_year += 1900;
458    }
459    tm.tm_year -= 1900;
460    tm.tm_mon -= 1;
461    *t = _der_timegm (&tm);
462    return 0;
463}
464
465static int
466der_get_time (const unsigned char *p, size_t len,
467	      time_t *data, size_t *size)
468{
469    char *times;
470    int e;
471
472    if (len > len + 1 || len == 0)
473	return ASN1_BAD_LENGTH;
474
475    times = malloc(len + 1);
476    if (times == NULL)
477	return ENOMEM;
478    memcpy(times, p, len);
479    times[len] = '\0';
480    e = generalizedtime2time(times, data);
481    free (times);
482    if(size) *size = len;
483    return e;
484}
485
486int
487der_get_generalized_time (const unsigned char *p, size_t len,
488			  time_t *data, size_t *size)
489{
490    return der_get_time(p, len, data, size);
491}
492
493int
494der_get_utctime (const unsigned char *p, size_t len,
495			  time_t *data, size_t *size)
496{
497    return der_get_time(p, len, data, size);
498}
499
500int
501der_get_oid (const unsigned char *p, size_t len,
502	     heim_oid *data, size_t *size)
503{
504    size_t n;
505    size_t oldlen = len;
506
507    if (len < 1)
508	return ASN1_OVERRUN;
509
510    if (len > len + 1)
511	return ASN1_BAD_LENGTH;
512
513    if (len + 1 > UINT_MAX/sizeof(data->components[0]))
514	return ERANGE;
515
516    data->components = malloc((len + 1) * sizeof(data->components[0]));
517    if (data->components == NULL)
518	return ENOMEM;
519    data->components[0] = (*p) / 40;
520    data->components[1] = (*p) % 40;
521    --len;
522    ++p;
523    for (n = 2; len > 0; ++n) {
524	unsigned u = 0, u1;
525
526	do {
527	    --len;
528	    u1 = u * 128 + (*p++ % 128);
529	    /* check that we don't overflow the element */
530	    if (u1 < u) {
531		der_free_oid(data);
532		return ASN1_OVERRUN;
533	    }
534	    u = u1;
535	} while (len > 0 && p[-1] & 0x80);
536	data->components[n] = u;
537    }
538    if (n > 2 && p[-1] & 0x80) {
539	der_free_oid (data);
540	return ASN1_OVERRUN;
541    }
542    data->length = n;
543    if (size)
544	*size = oldlen;
545    return 0;
546}
547
548int
549der_get_tag (const unsigned char *p, size_t len,
550	     Der_class *class, Der_type *type,
551	     unsigned int *tag, size_t *size)
552{
553    size_t ret = 0;
554    if (len < 1)
555	return ASN1_OVERRUN;
556    *class = (Der_class)(((*p) >> 6) & 0x03);
557    *type = (Der_type)(((*p) >> 5) & 0x01);
558    *tag = (*p) & 0x1f;
559    p++; len--; ret++;
560    if(*tag == 0x1f) {
561	unsigned int continuation;
562	unsigned int tag1;
563	*tag = 0;
564	do {
565	    if(len < 1)
566		return ASN1_OVERRUN;
567	    continuation = *p & 128;
568	    tag1 = *tag * 128 + (*p % 128);
569	    /* check that we don't overflow the tag */
570	    if (tag1 < *tag)
571		return ASN1_OVERFLOW;
572	    *tag = tag1;
573	    p++; len--; ret++;
574	} while(continuation);
575    }
576    if(size) *size = ret;
577    return 0;
578}
579
580int
581der_match_tag (const unsigned char *p, size_t len,
582	       Der_class class, Der_type type,
583	       unsigned int tag, size_t *size)
584{
585    Der_type thistype;
586    int e;
587
588    e = der_match_tag2(p, len, class, &thistype, tag, size);
589    if (e) return e;
590    if (thistype != type) return ASN1_BAD_ID;
591    return 0;
592}
593
594int
595der_match_tag2 (const unsigned char *p, size_t len,
596		Der_class class, Der_type *type,
597		unsigned int tag, size_t *size)
598{
599    size_t l;
600    Der_class thisclass;
601    unsigned int thistag;
602    int e;
603
604    e = der_get_tag (p, len, &thisclass, type, &thistag, &l);
605    if (e) return e;
606    if (class != thisclass)
607	return ASN1_BAD_ID;
608    if(tag > thistag)
609	return ASN1_MISPLACED_FIELD;
610    if(tag < thistag)
611	return ASN1_MISSING_FIELD;
612    if(size) *size = l;
613    return 0;
614}
615
616int
617der_match_tag_and_length (const unsigned char *p, size_t len,
618			  Der_class class, Der_type *type, unsigned int tag,
619			  size_t *length_ret, size_t *size)
620{
621    size_t l, ret = 0;
622    int e;
623
624    e = der_match_tag2 (p, len, class, type, tag, &l);
625    if (e) return e;
626    p += l;
627    len -= l;
628    ret += l;
629    e = der_get_length (p, len, length_ret, &l);
630    if (e) return e;
631    if(size) *size = ret + l;
632    return 0;
633}
634
635
636
637/*
638 * Old versions of DCE was based on a very early beta of the MIT code,
639 * which used MAVROS for ASN.1 encoding. MAVROS had the interesting
640 * feature that it encoded data in the forward direction, which has
641 * it's problems, since you have no idea how long the data will be
642 * until after you're done. MAVROS solved this by reserving one byte
643 * for length, and later, if the actual length was longer, it reverted
644 * to indefinite, BER style, lengths. The version of MAVROS used by
645 * the DCE people could apparently generate correct X.509 DER encodings, and
646 * did this by making space for the length after encoding, but
647 * unfortunately this feature wasn't used with Kerberos.
648 */
649
650int
651_heim_fix_dce(size_t reallen, size_t *len)
652{
653    if(reallen == ASN1_INDEFINITE)
654	return 1;
655    if(*len < reallen)
656	return -1;
657    *len = reallen;
658    return 0;
659}
660
661int
662der_get_bit_string (const unsigned char *p, size_t len,
663		    heim_bit_string *data, size_t *size)
664{
665    if (len < 1)
666	return ASN1_OVERRUN;
667    if (p[0] > 7)
668	return ASN1_BAD_FORMAT;
669    if (len - 1 == 0 && p[0] != 0)
670	return ASN1_BAD_FORMAT;
671    /* check if any of the three upper bits are set
672     * any of them will cause a interger overrun */
673    if ((len - 1) >> (sizeof(len) * 8 - 3))
674	return ASN1_OVERRUN;
675    data->length = (len - 1) * 8;
676    data->data = malloc(len - 1);
677    if (data->data == NULL && (len - 1) != 0)
678	return ENOMEM;
679    /* copy data is there is data to copy */
680    if (len - 1 != 0) {
681      memcpy (data->data, p + 1, len - 1);
682      data->length -= p[0];
683    }
684    if(size) *size = len;
685    return 0;
686}
687