summaryrefslogtreecommitdiffstats
path: root/libcli/auth/spnego_parse.c
blob: f7f19b107788f7a926b1bd691e597625da5c43fa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
/*
   Unix SMB/CIFS implementation.

   RFC2478 Compliant SPNEGO implementation

   Copyright (C) Jim McDonough <jmcd@us.ibm.com>   2003

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.


   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "../libcli/auth/spnego.h"
#include "../lib/util/asn1.h"

static bool read_negTokenInit(struct asn1_data *asn1, TALLOC_CTX *mem_ctx,
			      struct spnego_negTokenInit *token)
{
	ZERO_STRUCTP(token);

	if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
	if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;

	while (asn1_tag_remaining(asn1) > 0) {
		int i;
		uint8_t context;

		if (!asn1_peek_uint8(asn1, &context)) {
			asn1_set_error(asn1);
			break;
		}

		switch (context) {
		/* Read mechTypes */
		case ASN1_CONTEXT(0): {
			const char **mechTypes;

			if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
			if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;

			mechTypes = talloc(mem_ctx, const char *);
			if (mechTypes == NULL) {
				asn1_set_error(asn1);
				return false;
			}
			for (i = 0; asn1_tag_remaining(asn1) > 0; i++) {
				char *oid;
				const char **p;
				p = talloc_realloc(mem_ctx,
						   mechTypes,
						   const char *, i+2);
				if (p == NULL) {
					talloc_free(mechTypes);
					asn1_set_error(asn1);
					return false;
				}
				mechTypes = p;

				if (!asn1_read_OID(asn1, mechTypes, &oid)) return false;
				mechTypes[i] = oid;
			}
			mechTypes[i] = NULL;
			token->mechTypes = mechTypes;

			asn1_end_tag(asn1);
			asn1_end_tag(asn1);
			break;
		}
		/* Read reqFlags */
		case ASN1_CONTEXT(1):
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(1))) return false;
			if (!asn1_read_BitString(asn1, mem_ctx, &token->reqFlags,
					    &token->reqFlagsPadding)) return false;
			if (!asn1_end_tag(asn1)) return false;
			break;
                /* Read mechToken */
		case ASN1_CONTEXT(2):
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(2))) return false;
			if (!asn1_read_OctetString(asn1, mem_ctx, &token->mechToken)) return false;
			if (!asn1_end_tag(asn1)) return false;
			break;
		/* Read mecListMIC */
		case ASN1_CONTEXT(3):
		{
			uint8_t type_peek;
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(3))) return false;
			if (!asn1_peek_uint8(asn1, &type_peek)) {
				asn1_set_error(asn1);
				break;
			}
			if (type_peek == ASN1_OCTET_STRING) {
				if (!asn1_read_OctetString(asn1, mem_ctx,
						      &token->mechListMIC)) return false;
			} else {
				/* RFC 2478 says we have an Octet String here,
				   but W2k sends something different... */
				char *mechListMIC;
				if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;
				if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
				if (!asn1_read_GeneralString(asn1, mem_ctx, &mechListMIC)) return false;
				if (!asn1_end_tag(asn1)) return false;
				if (!asn1_end_tag(asn1)) return false;

				token->targetPrincipal = mechListMIC;
			}
			if (!asn1_end_tag(asn1)) return false;
			break;
		}
		default:
			asn1_set_error(asn1);
			break;
		}
	}

	if (!asn1_end_tag(asn1)) return false;
	if (!asn1_end_tag(asn1)) return false;

	return !asn1_has_error(asn1);
}

static bool write_negTokenInit(struct asn1_data *asn1, struct spnego_negTokenInit *token)
{
	if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
	if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;

	/* Write mechTypes */
	if (token->mechTypes && *token->mechTypes) {
		int i;

		if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
		if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;
		for (i = 0; token->mechTypes[i]; i++) {
			if (!asn1_write_OID(asn1, token->mechTypes[i])) return false;
		}
		if (!asn1_pop_tag(asn1)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	/* write reqFlags */
	if (token->reqFlags.length > 0) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(1))) return false;
		if (!asn1_write_BitString(asn1, token->reqFlags.data,
				     token->reqFlags.length,
				     token->reqFlagsPadding)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	/* write mechToken */
	if (token->mechToken.data) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(2))) return false;
		if (!asn1_write_OctetString(asn1, token->mechToken.data,
				       token->mechToken.length)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	/* write mechListMIC */
	if (token->mechListMIC.data) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(3))) return false;
#if 0
		/* This is what RFC 2478 says ... */
		asn1_write_OctetString(asn1, token->mechListMIC.data,
				       token->mechListMIC.length);
#else
		/* ... but unfortunately this is what Windows
		   sends/expects */
		if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
		if (!asn1_push_tag(asn1, ASN1_GENERAL_STRING)) return false;
		if (!asn1_write(asn1, token->mechListMIC.data,
			   token->mechListMIC.length)) return false;
		if (!asn1_pop_tag(asn1)) return false;
		if (!asn1_pop_tag(asn1)) return false;
		if (!asn1_pop_tag(asn1)) return false;
#endif
		if (!asn1_pop_tag(asn1)) return false;
	}

	if (!asn1_pop_tag(asn1)) return false;
	if (!asn1_pop_tag(asn1)) return false;

	return !asn1_has_error(asn1);
}

static bool read_negTokenTarg(struct asn1_data *asn1, TALLOC_CTX *mem_ctx,
			      struct spnego_negTokenTarg *token)
{
	ZERO_STRUCTP(token);

	if (!asn1_start_tag(asn1, ASN1_CONTEXT(1))) return false;
	if (!asn1_start_tag(asn1, ASN1_SEQUENCE(0))) return false;

	while (asn1_tag_remaining(asn1) > 0) {
		uint8_t context;
		uint8_t neg_result;
		char *oid;

		if (!asn1_peek_uint8(asn1, &context)) {
			asn1_set_error(asn1);
			break;
		}

		switch (context) {
		case ASN1_CONTEXT(0):
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(0))) return false;
			if (!asn1_start_tag(asn1, ASN1_ENUMERATED)) return false;
			if (!asn1_read_uint8(asn1, &neg_result)) return false;
			token->negResult = neg_result;
			if (!asn1_end_tag(asn1)) return false;
			if (!asn1_end_tag(asn1)) return false;
			break;
		case ASN1_CONTEXT(1):
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(1))) return false;
			if (!asn1_read_OID(asn1, mem_ctx, &oid)) return false;
			token->supportedMech = oid;
			if (!asn1_end_tag(asn1)) return false;
			break;
		case ASN1_CONTEXT(2):
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(2))) return false;
			if (!asn1_read_OctetString(asn1, mem_ctx, &token->responseToken)) return false;
			if (!asn1_end_tag(asn1)) return false;
			break;
		case ASN1_CONTEXT(3):
			if (!asn1_start_tag(asn1, ASN1_CONTEXT(3))) return false;
			if (!asn1_read_OctetString(asn1, mem_ctx, &token->mechListMIC)) return false;
			if (!asn1_end_tag(asn1)) return false;
			break;
		default:
			asn1_set_error(asn1);
			break;
		}
	}

	if (!asn1_end_tag(asn1)) return false;
	if (!asn1_end_tag(asn1)) return false;

	return !asn1_has_error(asn1);
}

static bool write_negTokenTarg(struct asn1_data *asn1, struct spnego_negTokenTarg *token)
{
	if (!asn1_push_tag(asn1, ASN1_CONTEXT(1))) return false;
	if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) return false;

	if (token->negResult != SPNEGO_NONE_RESULT) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(0))) return false;
		if (!asn1_write_enumerated(asn1, token->negResult)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	if (token->supportedMech) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(1))) return false;
		if (!asn1_write_OID(asn1, token->supportedMech)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	if (token->responseToken.data) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(2))) return false;
		if (!asn1_write_OctetString(asn1, token->responseToken.data,
				       token->responseToken.length)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	if (token->mechListMIC.data) {
		if (!asn1_push_tag(asn1, ASN1_CONTEXT(3))) return false;
		if (!asn1_write_OctetString(asn1, token->mechListMIC.data,
				      token->mechListMIC.length)) return false;
		if (!asn1_pop_tag(asn1)) return false;
	}

	if (!asn1_pop_tag(asn1)) return false;
	if (!asn1_pop_tag(asn1)) return false;

	return !asn1_has_error(asn1);
}

ssize_t spnego_read_data(TALLOC_CTX *mem_ctx, DATA_BLOB data, struct spnego_data *token)
{
	struct asn1_data *asn1;
	ssize_t ret = -1;
	uint8_t context;

	ZERO_STRUCTP(token);

	if (data.length == 0) {
		return ret;
	}

	asn1 = asn1_init(mem_ctx, ASN1_MAX_TREE_DEPTH);
	if (asn1 == NULL) {
		return -1;
	}

	if (!asn1_load(asn1, data)) goto err;

	if (!asn1_peek_uint8(asn1, &context)) {
		asn1_set_error(asn1);
	} else {
		switch (context) {
		case ASN1_APPLICATION(0):
			if (!asn1_start_tag(asn1, ASN1_APPLICATION(0))) goto err;
			if (!asn1_check_OID(asn1, OID_SPNEGO)) goto err;
			if (read_negTokenInit(asn1, mem_ctx, &token->negTokenInit)) {
				token->type = SPNEGO_NEG_TOKEN_INIT;
			}
			if (!asn1_end_tag(asn1)) goto err;
			break;
		case ASN1_CONTEXT(1):
			if (read_negTokenTarg(asn1, mem_ctx, &token->negTokenTarg)) {
				token->type = SPNEGO_NEG_TOKEN_TARG;
			}
			break;
		default:
			asn1_set_error(asn1);
			break;
		}
	}

	if (!asn1_has_error(asn1)) {
		ret = asn1_current_ofs(asn1);
	}

  err:

	asn1_free(asn1);

	return ret;
}

ssize_t spnego_write_data(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, struct spnego_data *spnego)
{
	struct asn1_data *asn1 = asn1_init(mem_ctx, ASN1_MAX_TREE_DEPTH);
	ssize_t ret = -1;

	if (asn1 == NULL) {
		return -1;
	}

	switch (spnego->type) {
	case SPNEGO_NEG_TOKEN_INIT:
		if (!asn1_push_tag(asn1, ASN1_APPLICATION(0))) goto err;
		if (!asn1_write_OID(asn1, OID_SPNEGO)) goto err;
		if (!write_negTokenInit(asn1, &spnego->negTokenInit)) goto err;
		if (!asn1_pop_tag(asn1)) goto err;
		break;
	case SPNEGO_NEG_TOKEN_TARG:
		write_negTokenTarg(asn1, &spnego->negTokenTarg);
		break;
	default:
		asn1_set_error(asn1);
		break;
	}

	if (!asn1_extract_blob(asn1, mem_ctx, blob)) {
		goto err;
	}

	ret = asn1_current_ofs(asn1);

  err:

	asn1_free(asn1);

	return ret;
}

bool spnego_free_data(struct spnego_data *spnego)
{
	bool ret = true;

	if (!spnego) goto out;

	switch(spnego->type) {
	case SPNEGO_NEG_TOKEN_INIT:
		if (spnego->negTokenInit.mechTypes) {
			talloc_free(discard_const(spnego->negTokenInit.mechTypes));
		}
		data_blob_free(&spnego->negTokenInit.reqFlags);
		data_blob_free(&spnego->negTokenInit.mechToken);
		data_blob_free(&spnego->negTokenInit.mechListMIC);
		talloc_free(spnego->negTokenInit.targetPrincipal);
		break;
	case SPNEGO_NEG_TOKEN_TARG:
		if (spnego->negTokenTarg.supportedMech) {
			talloc_free(discard_const(spnego->negTokenTarg.supportedMech));
		}
		data_blob_free(&spnego->negTokenTarg.responseToken);
		data_blob_free(&spnego->negTokenTarg.mechListMIC);
		break;
	default:
		ret = false;
		break;
	}
	ZERO_STRUCTP(spnego);
out:
	return ret;
}

bool spnego_write_mech_types(TALLOC_CTX *mem_ctx,
			     const char * const *mech_types,
			     DATA_BLOB *blob)
{
	bool ret = false;
	struct asn1_data *asn1 = asn1_init(mem_ctx, ASN1_MAX_TREE_DEPTH);

	if (asn1 == NULL) {
		return false;
	}

	/* Write mechTypes */
	if (mech_types && *mech_types) {
		int i;

		if (!asn1_push_tag(asn1, ASN1_SEQUENCE(0))) goto err;
		for (i = 0; mech_types[i]; i++) {
			if (!asn1_write_OID(asn1, mech_types[i])) goto err;
		}
		if (!asn1_pop_tag(asn1)) goto err;
	}

	if (asn1_has_error(asn1)) {
		goto err;
	}

	if (!asn1_extract_blob(asn1, mem_ctx, blob)) {
		goto err;
	}

	ret = true;

  err:

	asn1_free(asn1);

	return ret;
}