1/*
2   Unix SMB/CIFS implementation.
3   simple SPNEGO routines
4   Copyright (C) Andrew Tridgell 2001
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 2 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software
18   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19*/
20
21#include "includes.h"
22
23/* free an asn1 structure */
24void asn1_free(ASN1_DATA *data)
25{
26	struct nesting *nesting = data->nesting;
27
28	while (nesting) {
29		struct nesting *nnext = nesting->next;
30		free(nesting);
31		nesting = nnext;
32	};
33	data->nesting = NULL;
34	SAFE_FREE(data->data);
35}
36
37/* write to the ASN1 buffer, advancing the buffer pointer */
38BOOL asn1_write(ASN1_DATA *data, const void *p, int len)
39{
40	if (data->has_error) return False;
41	if (data->length < data->ofs+len) {
42		data->data = SMB_REALLOC_ARRAY(data->data, unsigned char,
43					       data->ofs+len);
44		if (!data->data) {
45			data->has_error = True;
46			return False;
47		}
48		data->length = data->ofs+len;
49	}
50	memcpy(data->data + data->ofs, p, len);
51	data->ofs += len;
52	return True;
53}
54
55/* useful fn for writing a uint8 */
56BOOL asn1_write_uint8(ASN1_DATA *data, uint8 v)
57{
58	return asn1_write(data, &v, 1);
59}
60
61/* push a tag onto the asn1 data buffer. Used for nested structures */
62BOOL asn1_push_tag(ASN1_DATA *data, uint8 tag)
63{
64	struct nesting *nesting;
65
66	asn1_write_uint8(data, tag);
67	nesting = SMB_MALLOC_P(struct nesting);
68	if (!nesting) {
69		data->has_error = True;
70		return False;
71	}
72
73	nesting->start = data->ofs;
74	nesting->next = data->nesting;
75	data->nesting = nesting;
76	return asn1_write_uint8(data, 0xff);
77}
78
79/* pop a tag */
80BOOL asn1_pop_tag(ASN1_DATA *data)
81{
82	struct nesting *nesting;
83	size_t len;
84
85	if (data->has_error) {
86		return False;
87	}
88
89	nesting = data->nesting;
90
91	if (!nesting) {
92		data->has_error = True;
93		return False;
94	}
95	len = data->ofs - (nesting->start+1);
96	/* yes, this is ugly. We don't know in advance how many bytes the length
97	   of a tag will take, so we assumed 1 byte. If we were wrong then we
98	   need to correct our mistake */
99	if (len > 0xFFFF) {
100		data->data[nesting->start] = 0x83;
101		if (!asn1_write_uint8(data, 0)) return False;
102		if (!asn1_write_uint8(data, 0)) return False;
103		if (!asn1_write_uint8(data, 0)) return False;
104		memmove(data->data+nesting->start+4, data->data+nesting->start+1, len);
105		data->data[nesting->start+1] = (len>>16) & 0xFF;
106		data->data[nesting->start+2] = (len>>8) & 0xFF;
107		data->data[nesting->start+3] = len&0xff;
108	} else if (len > 255) {
109		data->data[nesting->start] = 0x82;
110		if (!asn1_write_uint8(data, 0)) return False;
111		if (!asn1_write_uint8(data, 0)) return False;
112		memmove(data->data+nesting->start+3, data->data+nesting->start+1, len);
113		data->data[nesting->start+1] = len>>8;
114		data->data[nesting->start+2] = len&0xff;
115	} else if (len > 127) {
116		data->data[nesting->start] = 0x81;
117		if (!asn1_write_uint8(data, 0)) return False;
118		memmove(data->data+nesting->start+2, data->data+nesting->start+1, len);
119		data->data[nesting->start+1] = len;
120	} else {
121		data->data[nesting->start] = len;
122	}
123
124	data->nesting = nesting->next;
125	free(nesting);
126	return True;
127}
128
129
130/* write an integer */
131BOOL asn1_write_Integer(ASN1_DATA *data, int i)
132{
133	if (!asn1_push_tag(data, ASN1_INTEGER)) return False;
134	do {
135		asn1_write_uint8(data, i);
136		i = i >> 8;
137	} while (i);
138	return asn1_pop_tag(data);
139}
140
141/* write an object ID to a ASN1 buffer */
142BOOL asn1_write_OID(ASN1_DATA *data, const char *OID)
143{
144	unsigned v, v2;
145	const char *p = (const char *)OID;
146	char *newp;
147
148	if (!asn1_push_tag(data, ASN1_OID))
149		return False;
150	v = strtol(p, &newp, 10);
151	p = newp;
152	v2 = strtol(p, &newp, 10);
153	p = newp;
154	if (!asn1_write_uint8(data, 40*v + v2))
155		return False;
156
157	while (*p) {
158		v = strtol(p, &newp, 10);
159		p = newp;
160		if (v >= (1<<28)) asn1_write_uint8(data, 0x80 | ((v>>28)&0xff));
161		if (v >= (1<<21)) asn1_write_uint8(data, 0x80 | ((v>>21)&0xff));
162		if (v >= (1<<14)) asn1_write_uint8(data, 0x80 | ((v>>14)&0xff));
163		if (v >= (1<<7)) asn1_write_uint8(data, 0x80 | ((v>>7)&0xff));
164		if (!asn1_write_uint8(data, v&0x7f))
165			return False;
166	}
167	return asn1_pop_tag(data);
168}
169
170/* write an octet string */
171BOOL asn1_write_OctetString(ASN1_DATA *data, const void *p, size_t length)
172{
173	asn1_push_tag(data, ASN1_OCTET_STRING);
174	asn1_write(data, p, length);
175	asn1_pop_tag(data);
176	return !data->has_error;
177}
178
179/* write a general string */
180BOOL asn1_write_GeneralString(ASN1_DATA *data, const char *s)
181{
182	asn1_push_tag(data, ASN1_GENERAL_STRING);
183	asn1_write(data, s, strlen(s));
184	asn1_pop_tag(data);
185	return !data->has_error;
186}
187
188/* write a BOOLEAN */
189BOOL asn1_write_BOOLEAN(ASN1_DATA *data, BOOL v)
190{
191	asn1_write_uint8(data, ASN1_BOOLEAN);
192	asn1_write_uint8(data, v);
193	return !data->has_error;
194}
195
196/* write a BOOLEAN - hmm, I suspect this one is the correct one, and the
197   above boolean is bogus. Need to check */
198BOOL asn1_write_BOOLEAN2(ASN1_DATA *data, BOOL v)
199{
200	asn1_push_tag(data, ASN1_BOOLEAN);
201	asn1_write_uint8(data, v);
202	asn1_pop_tag(data);
203	return !data->has_error;
204}
205
206/* check a BOOLEAN */
207BOOL asn1_check_BOOLEAN(ASN1_DATA *data, BOOL v)
208{
209	uint8 b = 0;
210
211	asn1_read_uint8(data, &b);
212	if (b != ASN1_BOOLEAN) {
213		data->has_error = True;
214		return False;
215	}
216	asn1_read_uint8(data, &b);
217	if (b != v) {
218		data->has_error = True;
219		return False;
220	}
221	return !data->has_error;
222}
223
224
225/* load a ASN1_DATA structure with a lump of data, ready to be parsed */
226BOOL asn1_load(ASN1_DATA *data, DATA_BLOB blob)
227{
228	ZERO_STRUCTP(data);
229	data->data = (unsigned char *)memdup(blob.data, blob.length);
230	if (!data->data) {
231		data->has_error = True;
232		return False;
233	}
234	data->length = blob.length;
235	return True;
236}
237
238/* read from a ASN1 buffer, advancing the buffer pointer */
239BOOL asn1_read(ASN1_DATA *data, void *p, int len)
240{
241	if (data->has_error)
242		return False;
243
244	if (len < 0 || data->ofs + len < data->ofs || data->ofs + len < len) {
245		data->has_error = True;
246		return False;
247	}
248
249	if (data->ofs + len > data->length) {
250		data->has_error = True;
251		return False;
252	}
253	memcpy(p, data->data + data->ofs, len);
254	data->ofs += len;
255	return True;
256}
257
258/* read a uint8 from a ASN1 buffer */
259BOOL asn1_read_uint8(ASN1_DATA *data, uint8 *v)
260{
261	return asn1_read(data, v, 1);
262}
263
264/* start reading a nested asn1 structure */
265BOOL asn1_start_tag(ASN1_DATA *data, uint8 tag)
266{
267	uint8 b;
268	struct nesting *nesting;
269
270	if (!asn1_read_uint8(data, &b))
271		return False;
272
273	if (b != tag) {
274		data->has_error = True;
275		return False;
276	}
277	nesting = SMB_MALLOC_P(struct nesting);
278	if (!nesting) {
279		data->has_error = True;
280		return False;
281	}
282
283	if (!asn1_read_uint8(data, &b)) {
284		SAFE_FREE(nesting);
285		return False;
286	}
287
288	if (b & 0x80) {
289		int n = b & 0x7f;
290		if (!asn1_read_uint8(data, &b)) {
291			SAFE_FREE(nesting);
292			return False;
293		}
294		nesting->taglen = b;
295		while (n > 1) {
296			if (!asn1_read_uint8(data, &b)) {
297				SAFE_FREE(nesting);
298				return False;
299			}
300			nesting->taglen = (nesting->taglen << 8) | b;
301			n--;
302		}
303	} else {
304		nesting->taglen = b;
305	}
306	nesting->start = data->ofs;
307	nesting->next = data->nesting;
308	data->nesting = nesting;
309	return !data->has_error;
310}
311
312
313/* stop reading a tag */
314BOOL asn1_end_tag(ASN1_DATA *data)
315{
316	struct nesting *nesting;
317
318	/* make sure we read it all */
319	if (asn1_tag_remaining(data) != 0) {
320		data->has_error = True;
321		return False;
322	}
323
324	nesting = data->nesting;
325
326	if (!nesting) {
327		data->has_error = True;
328		return False;
329	}
330
331	data->nesting = nesting->next;
332	free(nesting);
333	return True;
334}
335
336/* work out how many bytes are left in this nested tag */
337int asn1_tag_remaining(ASN1_DATA *data)
338{
339	if (data->has_error)
340		return 0;
341
342	if (!data->nesting) {
343		data->has_error = True;
344		return -1;
345	}
346	return data->nesting->taglen - (data->ofs - data->nesting->start);
347}
348
349/* read an object ID from a ASN1 buffer */
350BOOL asn1_read_OID(ASN1_DATA *data, char **OID)
351{
352	uint8 b;
353	pstring oid_str;
354	fstring el;
355
356	*OID = NULL;
357
358	if (!asn1_start_tag(data, ASN1_OID)) {
359		return False;
360	}
361	asn1_read_uint8(data, &b);
362
363	oid_str[0] = 0;
364	fstr_sprintf(el, "%u",  b/40);
365	pstrcat(oid_str, el);
366	fstr_sprintf(el, " %u",  b%40);
367	pstrcat(oid_str, el);
368
369	while (asn1_tag_remaining(data) > 0) {
370		unsigned v = 0;
371		do {
372			asn1_read_uint8(data, &b);
373			v = (v<<7) | (b&0x7f);
374		} while (!data->has_error && b & 0x80);
375		fstr_sprintf(el, " %u",  v);
376		pstrcat(oid_str, el);
377	}
378
379	asn1_end_tag(data);
380
381	if (!data->has_error) {
382	  	*OID = SMB_STRDUP(oid_str);
383	}
384
385	return !data->has_error;
386}
387
388/* check that the next object ID is correct */
389BOOL asn1_check_OID(ASN1_DATA *data, const char *OID)
390{
391	char *id;
392
393	if (!asn1_read_OID(data, &id)) {
394		return False;
395	}
396
397	if (strcmp(id, OID) != 0) {
398		data->has_error = True;
399		return False;
400	}
401	free(id);
402	return True;
403}
404
405/* read a GeneralString from a ASN1 buffer */
406BOOL asn1_read_GeneralString(ASN1_DATA *data, char **s)
407{
408	int len;
409	char *str;
410
411	*s = NULL;
412
413	if (!asn1_start_tag(data, ASN1_GENERAL_STRING)) {
414		return False;
415	}
416	len = asn1_tag_remaining(data);
417	if (len < 0) {
418		data->has_error = True;
419		return False;
420	}
421	str = SMB_MALLOC_ARRAY(char, len+1);
422	if (!str) {
423		data->has_error = True;
424		return False;
425	}
426	asn1_read(data, str, len);
427	str[len] = 0;
428	asn1_end_tag(data);
429
430	if (!data->has_error) {
431		*s = str;
432	}
433	return !data->has_error;
434}
435
436/* read a octet string blob */
437BOOL asn1_read_OctetString(ASN1_DATA *data, DATA_BLOB *blob)
438{
439	int len;
440	ZERO_STRUCTP(blob);
441	if (!asn1_start_tag(data, ASN1_OCTET_STRING)) return False;
442	len = asn1_tag_remaining(data);
443	if (len < 0) {
444		data->has_error = True;
445		return False;
446	}
447	*blob = data_blob(NULL, len);
448	asn1_read(data, blob->data, len);
449	asn1_end_tag(data);
450	return !data->has_error;
451}
452
453/* read an interger */
454BOOL asn1_read_Integer(ASN1_DATA *data, int *i)
455{
456	uint8 b;
457	*i = 0;
458
459	if (!asn1_start_tag(data, ASN1_INTEGER)) return False;
460	while (asn1_tag_remaining(data)>0) {
461		asn1_read_uint8(data, &b);
462		*i = (*i << 8) + b;
463	}
464	return asn1_end_tag(data);
465
466}
467
468/* check a enumarted value is correct */
469BOOL asn1_check_enumerated(ASN1_DATA *data, int v)
470{
471	uint8 b;
472	if (!asn1_start_tag(data, ASN1_ENUMERATED)) return False;
473	asn1_read_uint8(data, &b);
474	asn1_end_tag(data);
475
476	if (v != b)
477		data->has_error = False;
478
479	return !data->has_error;
480}
481
482/* write an enumarted value to the stream */
483BOOL asn1_write_enumerated(ASN1_DATA *data, uint8 v)
484{
485	if (!asn1_push_tag(data, ASN1_ENUMERATED)) return False;
486	asn1_write_uint8(data, v);
487	asn1_pop_tag(data);
488	return !data->has_error;
489}
490