summaryrefslogtreecommitdiff
path: root/libcli/auth/msrpc_parse.c
blob: 86ba2ec00d4d4d569db59a47e3d08969a25eeef6 (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
/* 
   Unix SMB/CIFS implementation.
   simple kerberos5/SPNEGO routines
   Copyright (C) Andrew Tridgell 2001
   Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2002
   Copyright (C) Andrew Bartlett 2002-2003
   
   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/msrpc_parse.h"

/*
  this is a tiny msrpc packet generator. I am only using this to
  avoid tying this code to a particular varient of our rpc code. This
  generator is not general enough for all our rpc needs, its just
  enough for the spnego/ntlmssp code

  format specifiers are:

  U = unicode string (input is unix string)
  a = address (input is char *unix_string)
      (1 byte type, 1 byte length, unicode/ASCII string, all inline)
  A = ASCII string (input is unix string)
  B = data blob (pointer + length)
  b = data blob in header (pointer + length)
  D
  d = word (4 bytes)
  C = constant ascii string
 */
NTSTATUS msrpc_gen(TALLOC_CTX *mem_ctx, 
	       DATA_BLOB *blob,
	       const char *format, ...)
{
	int i, j;
	bool ret;
	va_list ap;
	char *s;
	uint8_t *b;
	int head_size=0, data_size=0;
	int head_ofs, data_ofs;
	int *intargs;
	size_t n;

	DATA_BLOB *pointers;

	pointers = talloc_array(mem_ctx, DATA_BLOB, strlen(format));
	if (!pointers) {
		return NT_STATUS_NO_MEMORY;
	}
	intargs = talloc_array(pointers, int, strlen(format));
	if (!intargs) {
		return NT_STATUS_NO_MEMORY;
	}

	/* first scan the format to work out the header and body size */
	va_start(ap, format);
	for (i=0; format[i]; i++) {
		switch (format[i]) {
		case 'U':
			s = va_arg(ap, char *);
			head_size += 8;
			ret = push_ucs2_talloc(
				pointers,
				(smb_ucs2_t **)(void *)&pointers[i].data,
				s, &n);
			if (!ret) {
				va_end(ap);
				return map_nt_error_from_unix_common(errno);
			}
			pointers[i].length = n;
			pointers[i].length -= 2;
			data_size += pointers[i].length;
			break;
		case 'A':
			s = va_arg(ap, char *);
			head_size += 8;
			ret = push_ascii_talloc(
				pointers, (char **)(void *)&pointers[i].data,
				s, &n);
			if (!ret) {
				va_end(ap);
				return map_nt_error_from_unix_common(errno);
			}
			pointers[i].length = n;
			pointers[i].length -= 1;
			data_size += pointers[i].length;
			break;
		case 'a':
			j = va_arg(ap, int);
			intargs[i] = j;
			s = va_arg(ap, char *);
			ret = push_ucs2_talloc(
				pointers,
				(smb_ucs2_t **)(void *)&pointers[i].data,
				s, &n);
			if (!ret) {
				va_end(ap);
				return map_nt_error_from_unix_common(errno);
			}
			pointers[i].length = n;
			pointers[i].length -= 2;
			data_size += pointers[i].length + 4;
			break;
		case 'B':
			b = va_arg(ap, uint8_t *);
			head_size += 8;
			pointers[i].data = b;
			pointers[i].length = va_arg(ap, int);
			data_size += pointers[i].length;
			break;
		case 'b':
			b = va_arg(ap, uint8_t *);
			pointers[i].data = b;
			pointers[i].length = va_arg(ap, int);
			head_size += pointers[i].length;
			break;
		case 'd':
			j = va_arg(ap, int);
			intargs[i] = j;
			head_size += 4;
			break;
		case 'C':
			s = va_arg(ap, char *);
			pointers[i].data = (uint8_t *)s;
			pointers[i].length = strlen(s)+1;
			head_size += pointers[i].length;
			break;
		default:
			va_end(ap);
			return NT_STATUS_INVALID_PARAMETER;
		}
	}
	va_end(ap);

	if (head_size + data_size == 0) {
		return NT_STATUS_INVALID_PARAMETER;
	}

	/* allocate the space, then scan the format again to fill in the values */
	*blob = data_blob_talloc(mem_ctx, NULL, head_size + data_size);
	if (!blob->data) {
		return NT_STATUS_NO_MEMORY;
	}
	head_ofs = 0;
	data_ofs = head_size;

	va_start(ap, format);
	for (i=0; format[i]; i++) {
		switch (format[i]) {
		case 'U':
		case 'A':
		case 'B':
			n = pointers[i].length;
			SSVAL(blob->data, head_ofs, n); head_ofs += 2;
			SSVAL(blob->data, head_ofs, n); head_ofs += 2;
			SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
			if (pointers[i].data && n) /* don't follow null pointers... */
				memcpy(blob->data+data_ofs, pointers[i].data, n);
			data_ofs += n;
			break;
		case 'a':
			j = intargs[i];
			SSVAL(blob->data, data_ofs, j); data_ofs += 2;

			n = pointers[i].length;
			SSVAL(blob->data, data_ofs, n); data_ofs += 2;
			memcpy(blob->data+data_ofs, pointers[i].data, n);
			data_ofs += n;
			break;
		case 'd':
			j = intargs[i];
			SIVAL(blob->data, head_ofs, j); 
			head_ofs += 4;
			break;
		case 'b':
			n = pointers[i].length;
			if (pointers[i].data && n) {
				/* don't follow null pointers... */
				memcpy(blob->data + head_ofs, pointers[i].data, n);
			}
			head_ofs += n;
			break;
		case 'C':
			n = pointers[i].length;
			memcpy(blob->data + head_ofs, pointers[i].data, n);
			head_ofs += n;
			break;
		default:
			va_end(ap);
			return NT_STATUS_INVALID_PARAMETER;
		}
	}
	va_end(ap);
	
	talloc_free(pointers);

	return NT_STATUS_OK;
}


/* a helpful macro to avoid running over the end of our blob */
#define NEED_DATA(amount) \
if ((head_ofs + amount) > blob->length) { \
        va_end(ap); \
        return false; \
}

/**
  this is a tiny msrpc packet parser. This the the partner of msrpc_gen

  format specifiers are:

  U = unicode string (output is unix string)
  A = ascii string
  B = data blob
  b = data blob in header
  d = word (4 bytes)
  C = constant ascii string
 */

bool msrpc_parse(TALLOC_CTX *mem_ctx, 
		 const DATA_BLOB *blob,
		 const char *format, ...)
{
	int i;
	va_list ap;
	char **ps, *s;
	DATA_BLOB *b;
	size_t head_ofs = 0;
	uint16_t len1, len2;
	uint32_t ptr;
	uint32_t *v;
	bool ret = true;

	va_start(ap, format);
	for (i=0; format[i]; i++) {
		switch (format[i]) {
		case 'U':
			NEED_DATA(8);
			len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
			len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
			ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;

			ps = va_arg(ap, char **);
			if (len1 == 0 && len2 == 0) {
				*ps = talloc_strdup(mem_ctx, "");
				if (*ps == NULL) {
					ret = false;
					goto cleanup;
				}
			} else {
				/* make sure its in the right format - be strict */
				if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
					ret = false;
					goto cleanup;
				}
				if (len1 & 1) {
					/* if odd length and unicode */
					ret = false;
					goto cleanup;
				}
				if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
						blob->data + ptr < blob->data) {
					ret = false;
					goto cleanup;
				}

				if (0 < len1) {
					size_t pull_len;
					if (!convert_string_talloc(mem_ctx, CH_UTF16, CH_UNIX, 
								   blob->data + ptr, len1, 
								   ps, &pull_len)) {
						ret = false;
						goto cleanup;
					}
				} else {
					*ps = talloc_strdup(mem_ctx, "");
					if (*ps == NULL) {
						ret = false;
						goto cleanup;
					}
				}
			}
			break;
		case 'A':
			NEED_DATA(8);
			len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
			len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
			ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;

			ps = (char **)va_arg(ap, char **);
			/* make sure its in the right format - be strict */
			if (len1 == 0 && len2 == 0) {
				*ps = talloc_strdup(mem_ctx, "");
				if (*ps == NULL) {
					ret = false;
					goto cleanup;
				}
			} else {
				if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
					ret = false;
					goto cleanup;
				}

				if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
						blob->data + ptr < blob->data) {
					ret = false;
					goto cleanup;
				}

				if (0 < len1) {
					size_t pull_len;

					if (!convert_string_talloc(mem_ctx, CH_DOS, CH_UNIX, 
								   blob->data + ptr, len1, 
								   ps, &pull_len)) {
						ret = false;
						goto cleanup;
					}
				} else {
					*ps = talloc_strdup(mem_ctx, "");
					if (*ps == NULL) {
						ret = false;
						goto cleanup;
					}
				}
			}
			break;
		case 'B':
			NEED_DATA(8);
			len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
			len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
			ptr =  IVAL(blob->data, head_ofs); head_ofs += 4;

			b = (DATA_BLOB *)va_arg(ap, void *);
			if (len1 == 0 && len2 == 0) {
				*b = data_blob_talloc(mem_ctx, NULL, 0);
			} else {
				/* make sure its in the right format - be strict */
				if ((len1 != len2) || (ptr + len1 < ptr) || (ptr + len1 < len1) || (ptr + len1 > blob->length)) {
					ret = false;
					goto cleanup;
				}

				if (blob->data + ptr < (uint8_t *)(uintptr_t)ptr ||
						blob->data + ptr < blob->data) {
					ret = false;
					goto cleanup;
				}

				*b = data_blob_talloc(mem_ctx, blob->data + ptr, len1);
			}
			break;
		case 'b':
			b = (DATA_BLOB *)va_arg(ap, void *);
			len1 = va_arg(ap, unsigned int);
			/* make sure its in the right format - be strict */
			NEED_DATA(len1);
			if (blob->data + head_ofs < (uint8_t *)head_ofs ||
					blob->data + head_ofs < blob->data) {
				ret = false;
				goto cleanup;
			}

			*b = data_blob_talloc(mem_ctx, blob->data + head_ofs, len1);
			head_ofs += len1;
			break;
		case 'd':
			v = va_arg(ap, uint32_t *);
			NEED_DATA(4);
			*v = IVAL(blob->data, head_ofs); head_ofs += 4;
			break;
		case 'C':
			s = va_arg(ap, char *);

			if (blob->data + head_ofs < (uint8_t *)head_ofs ||
					blob->data + head_ofs < blob->data ||
			    (head_ofs + (strlen(s) + 1)) > blob->length) {
				ret = false;
				goto cleanup;
			}

			if (memcmp(blob->data + head_ofs, s, strlen(s)+1) != 0) {
				ret = false;
				goto cleanup;
			}
			head_ofs += (strlen(s) + 1);

			break;
		}
	}

cleanup:
	va_end(ap);
	return ret;
}