summaryrefslogtreecommitdiff
path: root/source4/auth/ntlmssp/ntlmssp_sign.c
blob: e560ad62dd7af4c50d648578c876c4ffeb0c3868 (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
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
/* 
 *  Unix SMB/CIFS implementation.
 *  Version 3.0
 *  NTLMSSP Signing routines
 *  Copyright (C) Luke Kenneth Casson Leighton 1996-2001
 *  Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003-2005
 *  
 *  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 2 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, write to the Free Software Foundation,
 *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "includes.h"
#include "auth/auth.h"
#include "auth/ntlmssp/ntlmssp.h"
#include "auth/ntlmssp/msrpc_parse.h"
#include "lib/crypto/crypto.h"
#include "auth/credentials/credentials.h"
#include "auth/gensec/gensec.h"

#define CLI_SIGN "session key to client-to-server signing key magic constant"
#define CLI_SEAL "session key to client-to-server sealing key magic constant"
#define SRV_SIGN "session key to server-to-client signing key magic constant"
#define SRV_SEAL "session key to server-to-client sealing key magic constant"

/**
 * Some notes on the NTLM2 code:
 *
 * NTLM2 is a AEAD system.  This means that the data encrypted is not
 * all the data that is signed.  In DCE-RPC case, the headers of the
 * DCE-RPC packets are also signed.  This prevents some of the
 * fun-and-games one might have by changing them.
 *
 */

static void calc_ntlmv2_key(TALLOC_CTX *mem_ctx, 
			    DATA_BLOB *subkey,
			    DATA_BLOB session_key, 
			    const char *constant)
{
	struct MD5Context ctx3;
	*subkey = data_blob_talloc(mem_ctx, NULL, 16);
	MD5Init(&ctx3);
	MD5Update(&ctx3, session_key.data, session_key.length);
	MD5Update(&ctx3, (const uint8_t *)constant, strlen(constant)+1);
	MD5Final(subkey->data, &ctx3);
}

enum ntlmssp_direction {
	NTLMSSP_SEND,
	NTLMSSP_RECEIVE
};

static NTSTATUS ntlmssp_make_packet_signature(struct gensec_ntlmssp_state *gensec_ntlmssp_state,
					      TALLOC_CTX *sig_mem_ctx, 
					      const uint8_t *data, size_t length, 
					      const uint8_t *whole_pdu, size_t pdu_length, 
					      enum ntlmssp_direction direction,
					      DATA_BLOB *sig, BOOL encrypt_sig)
{
	if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {

		HMACMD5Context ctx;
		uint8_t digest[16];
		uint8_t seq_num[4];

		*sig = data_blob_talloc(sig_mem_ctx, NULL, NTLMSSP_SIG_SIZE);
		if (!sig->data) {
			return NT_STATUS_NO_MEMORY;
		}
			
		switch (direction) {
		case NTLMSSP_SEND:
			SIVAL(seq_num, 0, gensec_ntlmssp_state->crypt.ntlm2.send_seq_num);
			gensec_ntlmssp_state->crypt.ntlm2.send_seq_num++;
			hmac_md5_init_limK_to_64(gensec_ntlmssp_state->crypt.ntlm2.send_sign_key.data, 
						 gensec_ntlmssp_state->crypt.ntlm2.send_sign_key.length, &ctx);
			break;
		case NTLMSSP_RECEIVE:
			SIVAL(seq_num, 0, gensec_ntlmssp_state->crypt.ntlm2.recv_seq_num);
			gensec_ntlmssp_state->crypt.ntlm2.recv_seq_num++;
			hmac_md5_init_limK_to_64(gensec_ntlmssp_state->crypt.ntlm2.recv_sign_key.data, 
						 gensec_ntlmssp_state->crypt.ntlm2.recv_sign_key.length, &ctx);
			break;
		}
		hmac_md5_update(seq_num, sizeof(seq_num), &ctx);
		hmac_md5_update(whole_pdu, pdu_length, &ctx);
		hmac_md5_final(digest, &ctx);

		if (encrypt_sig && gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
			switch (direction) {
			case NTLMSSP_SEND:
				arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state, digest, 8);
				break;
			case NTLMSSP_RECEIVE:
				arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm2.recv_seal_arcfour_state, digest, 8);
				break;
			}
		}

		SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
		memcpy(sig->data + 4, digest, 8);
		memcpy(sig->data + 12, seq_num, 4);

		DEBUG(10, ("NTLM2: created signature over %llu bytes of input:\n", (unsigned long long)pdu_length));
		dump_data(11, sig->data, sig->length);
			
	} else {
		uint32_t crc;
		crc = crc32_calc_buffer(data, length);
		if (!msrpc_gen(sig_mem_ctx, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, gensec_ntlmssp_state->crypt.ntlm.seq_num)) {
			return NT_STATUS_NO_MEMORY;
		}
		gensec_ntlmssp_state->crypt.ntlm.seq_num++;

		arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm.arcfour_state, sig->data+4, sig->length-4);

		DEBUG(10, ("NTLM1: created signature over %llu bytes of input:\n", (unsigned long long)length));
		dump_data(11, sig->data, sig->length);
	}
	return NT_STATUS_OK;
}

/* TODO: make this non-public */
_PUBLIC_ NTSTATUS gensec_ntlmssp_sign_packet(struct gensec_security *gensec_security, 
				    TALLOC_CTX *sig_mem_ctx, 
				    const uint8_t *data, size_t length, 
				    const uint8_t *whole_pdu, size_t pdu_length, 
				    DATA_BLOB *sig)
{
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;

	return ntlmssp_make_packet_signature(gensec_ntlmssp_state, sig_mem_ctx, 
					     data, length, 
					     whole_pdu, pdu_length, 
					     NTLMSSP_SEND, sig, True);
}

/**
 * Check the signature of an incoming packet 
 *
 */

NTSTATUS gensec_ntlmssp_check_packet(struct gensec_security *gensec_security, 
				     TALLOC_CTX *sig_mem_ctx, 
				     const uint8_t *data, size_t length, 
				     const uint8_t *whole_pdu, size_t pdu_length, 
				     const DATA_BLOB *sig)
{
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;

	DATA_BLOB local_sig;
	NTSTATUS nt_status;

	if (!gensec_ntlmssp_state->session_key.length) {
		DEBUG(3, ("NO session key, cannot check packet signature\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}

	nt_status = ntlmssp_make_packet_signature(gensec_ntlmssp_state, sig_mem_ctx, 
						  data, length, 
						  whole_pdu, pdu_length, 
						  NTLMSSP_RECEIVE, &local_sig, True);
	
	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
		return nt_status;
	}

	if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
		if (local_sig.length != sig->length ||
		    memcmp(local_sig.data, 
			   sig->data, sig->length) != 0) {
			DEBUG(5, ("BAD SIG NTLM2: wanted signature over %llu bytes of input:\n", (unsigned long long)pdu_length));
			dump_data(5, local_sig.data, local_sig.length);
			
			DEBUG(5, ("BAD SIG: got signature over %llu bytes of input:\n", (unsigned long long)pdu_length));
			dump_data(5, sig->data, sig->length);
			
			DEBUG(1, ("NTLMSSP NTLM2 packet check failed due to invalid signature on %llu bytes of input!\n", (unsigned long long)pdu_length));
			return NT_STATUS_ACCESS_DENIED;
		}
	} else {
		if (local_sig.length != sig->length ||
		    memcmp(local_sig.data + 8, 
			   sig->data + 8, sig->length - 8) != 0) {
			DEBUG(5, ("BAD SIG NTLM1: wanted signature of %llu bytes of input:\n", (unsigned long long)length));
			dump_data(5, local_sig.data, local_sig.length);
			
			DEBUG(5, ("BAD SIG: got signature of %llu bytes of input:\n", (unsigned long long)length));
			dump_data(5, sig->data, sig->length);
			
			DEBUG(1, ("NTLMSSP NTLM1 packet check failed due to invalid signature on %llu bytes of input:\n", (unsigned long long)length));
			return NT_STATUS_ACCESS_DENIED;
		}
	}
	dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);

	return NT_STATUS_OK;
}


/**
 * Seal data with the NTLMSSP algorithm
 *
 */

NTSTATUS gensec_ntlmssp_seal_packet(struct gensec_security *gensec_security, 
				    TALLOC_CTX *sig_mem_ctx, 
				    uint8_t *data, size_t length, 
				    const uint8_t *whole_pdu, size_t pdu_length, 
				    DATA_BLOB *sig)
{
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
	NTSTATUS nt_status;
	if (!gensec_ntlmssp_state->session_key.length) {
		DEBUG(3, ("NO session key, cannot seal packet\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}

	DEBUG(10,("ntlmssp_seal_data: seal\n"));
	dump_data_pw("ntlmssp clear data\n", data, length);
	if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
		/* The order of these two operations matters - we must first seal the packet,
		   then seal the sequence number - this is becouse the send_seal_hash is not
		   constant, but is is rather updated with each iteration */
		nt_status = ntlmssp_make_packet_signature(gensec_ntlmssp_state, sig_mem_ctx, 
							  data, length, 
							  whole_pdu, pdu_length, 
							  NTLMSSP_SEND, sig, False);
		arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state, data, length);
		if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
			arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state, sig->data+4, 8);
		}
	} else {
		uint32_t crc;
		crc = crc32_calc_buffer(data, length);
		if (!msrpc_gen(sig_mem_ctx, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, gensec_ntlmssp_state->crypt.ntlm.seq_num)) {
			return NT_STATUS_NO_MEMORY;
		}

		/* The order of these two operations matters - we must
		   first seal the packet, then seal the sequence
		   number - this is becouse the ntlmssp_hash is not
		   constant, but is is rather updated with each
		   iteration */

		arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm.arcfour_state, data, length);
		arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm.arcfour_state, sig->data+4, sig->length-4);
		/* increment counter on send */
		gensec_ntlmssp_state->crypt.ntlm.seq_num++;
		nt_status = NT_STATUS_OK;
	}
	dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
	dump_data_pw("ntlmssp sealed data\n", data, length);


	return nt_status;
}

/**
 * Unseal data with the NTLMSSP algorithm
 *
 */

/*
  wrappers for the ntlmssp_*() functions
*/
NTSTATUS gensec_ntlmssp_unseal_packet(struct gensec_security *gensec_security, 
				      TALLOC_CTX *sig_mem_ctx, 
				      uint8_t *data, size_t length, 
				      const uint8_t *whole_pdu, size_t pdu_length, 
				      const DATA_BLOB *sig)
{
	struct gensec_ntlmssp_state *gensec_ntlmssp_state = gensec_security->private_data;
	if (!gensec_ntlmssp_state->session_key.length) {
		DEBUG(3, ("NO session key, cannot unseal packet\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}

	dump_data_pw("ntlmssp sealed data\n", data, length);
	if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
		arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm2.recv_seal_arcfour_state, data, length);
	} else {
		arcfour_crypt_sbox(gensec_ntlmssp_state->crypt.ntlm.arcfour_state, data, length);
	}
	dump_data_pw("ntlmssp clear data\n", data, length);
	return gensec_ntlmssp_check_packet(gensec_security, sig_mem_ctx, data, length, whole_pdu, pdu_length, sig);
}

/**
   Initialise the state for NTLMSSP signing.
*/
/* TODO: make this non-public */
_PUBLIC_ NTSTATUS ntlmssp_sign_init(struct gensec_ntlmssp_state *gensec_ntlmssp_state)
{
	TALLOC_CTX *mem_ctx = talloc_new(gensec_ntlmssp_state);

	if (!mem_ctx) {
		return NT_STATUS_NO_MEMORY;
	}

	DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
	debug_ntlmssp_flags(gensec_ntlmssp_state->neg_flags);

	if (gensec_ntlmssp_state->session_key.length < 8) {
		talloc_free(mem_ctx);
		DEBUG(3, ("NO session key, cannot intialise signing\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}

	if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2)
	{
		DATA_BLOB weak_session_key = gensec_ntlmssp_state->session_key;
		const char *send_sign_const;
		const char *send_seal_const;
		const char *recv_sign_const;
		const char *recv_seal_const;

		DATA_BLOB send_seal_key;
		DATA_BLOB recv_seal_key;

		switch (gensec_ntlmssp_state->role) {
		case NTLMSSP_CLIENT:
			send_sign_const = CLI_SIGN;
			send_seal_const = CLI_SEAL;
			recv_sign_const = SRV_SIGN;
			recv_seal_const = SRV_SEAL;
			break;
		case NTLMSSP_SERVER:
			send_sign_const = SRV_SIGN;
			send_seal_const = SRV_SEAL;
			recv_sign_const = CLI_SIGN;
			recv_seal_const = CLI_SEAL;
			break;
		default:
			talloc_free(mem_ctx);
			return NT_STATUS_INTERNAL_ERROR;
		}
		
		gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state = talloc(gensec_ntlmssp_state, struct arcfour_state);
		NT_STATUS_HAVE_NO_MEMORY(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state);
		gensec_ntlmssp_state->crypt.ntlm2.recv_seal_arcfour_state = talloc(gensec_ntlmssp_state, struct arcfour_state);
		NT_STATUS_HAVE_NO_MEMORY(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state);

		/**
		   Weaken NTLMSSP keys to cope with down-level
		   clients, servers and export restrictions.
		   
		   We probably should have some parameters to control
		   this, once we get NTLM2 working.
		*/

		/* Key weakening was not performed on the master key
		 * for NTLM2 (in ntlmssp_weaken_keys()), but must be
		 * done on the encryption subkeys only.  That is why
		 * we don't have this code for the ntlmv1 case.
		 */

		if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
			
		} else if (gensec_ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
			weak_session_key.length = 7;
		} else { /* forty bits */
			weak_session_key.length = 5;
		}
		dump_data_pw("NTLMSSP weakend master key:\n",
			     weak_session_key.data, 
			     weak_session_key.length);

		/* SEND: sign key */
		calc_ntlmv2_key(gensec_ntlmssp_state, 
				&gensec_ntlmssp_state->crypt.ntlm2.send_sign_key, 
				gensec_ntlmssp_state->session_key, send_sign_const);
		dump_data_pw("NTLMSSP send sign key:\n",
			     gensec_ntlmssp_state->crypt.ntlm2.send_sign_key.data, 
			     gensec_ntlmssp_state->crypt.ntlm2.send_sign_key.length);
		
		/* SEND: seal ARCFOUR pad */
		calc_ntlmv2_key(mem_ctx, 
				&send_seal_key, 
				weak_session_key, send_seal_const);
		dump_data_pw("NTLMSSP send seal key:\n",
			     send_seal_key.data, 
			     send_seal_key.length);
		arcfour_init(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state, 
			     &send_seal_key);
		dump_data_pw("NTLMSSP send sesl hash:\n", 
			     gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state->sbox, 
			     sizeof(gensec_ntlmssp_state->crypt.ntlm2.send_seal_arcfour_state->sbox));

		/* RECV: sign key */
		calc_ntlmv2_key(gensec_ntlmssp_state, 
				&gensec_ntlmssp_state->crypt.ntlm2.recv_sign_key, 
				gensec_ntlmssp_state->session_key, recv_sign_const);
		dump_data_pw("NTLMSSP recv sign key:\n",
			     gensec_ntlmssp_state->crypt.ntlm2.recv_sign_key.data, 
			     gensec_ntlmssp_state->crypt.ntlm2.recv_sign_key.length);

		/* RECV: seal ARCFOUR pad */
		calc_ntlmv2_key(mem_ctx, 
				&recv_seal_key, 
				weak_session_key, recv_seal_const);
		dump_data_pw("NTLMSSP recv seal key:\n",
			     recv_seal_key.data, 
			     recv_seal_key.length);
		arcfour_init(gensec_ntlmssp_state->crypt.ntlm2.recv_seal_arcfour_state, 
			     &recv_seal_key);
		dump_data_pw("NTLMSSP receive seal hash:\n", 
			     gensec_ntlmssp_state->crypt.ntlm2.recv_seal_arcfour_state->sbox, 
			     sizeof(gensec_ntlmssp_state->crypt.ntlm2.recv_seal_arcfour_state->sbox));

		gensec_ntlmssp_state->crypt.ntlm2.send_seq_num = 0;
		gensec_ntlmssp_state->crypt.ntlm2.recv_seq_num = 0;

	} else {
		DATA_BLOB weak_session_key = ntlmssp_weakend_key(gensec_ntlmssp_state, mem_ctx);
		DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));

		gensec_ntlmssp_state->crypt.ntlm.arcfour_state = talloc(gensec_ntlmssp_state, struct arcfour_state);
		NT_STATUS_HAVE_NO_MEMORY(gensec_ntlmssp_state->crypt.ntlm.arcfour_state);

		arcfour_init(gensec_ntlmssp_state->crypt.ntlm.arcfour_state, 
			     &weak_session_key);
		dump_data_pw("NTLMSSP hash:\n", gensec_ntlmssp_state->crypt.ntlm.arcfour_state->sbox,
			     sizeof(gensec_ntlmssp_state->crypt.ntlm.arcfour_state->sbox));

		gensec_ntlmssp_state->crypt.ntlm.seq_num = 0;
	}

	talloc_free(mem_ctx);
	return NT_STATUS_OK;
}

size_t gensec_ntlmssp_sig_size(struct gensec_security *gensec_security, size_t data_size) 
{
	return NTLMSSP_SIG_SIZE;
}

NTSTATUS gensec_ntlmssp_wrap(struct gensec_security *gensec_security, 
			     TALLOC_CTX *sig_mem_ctx, 
			     const DATA_BLOB *in, 
			     DATA_BLOB *out)
{
	DATA_BLOB sig;
	NTSTATUS nt_status;

	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {

		*out = data_blob_talloc(sig_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
		if (!out->data) {
			return NT_STATUS_NO_MEMORY;
		}
		memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
		
	        nt_status = gensec_ntlmssp_seal_packet(gensec_security, sig_mem_ctx, 
						       out->data + NTLMSSP_SIG_SIZE, 
						       out->length - NTLMSSP_SIG_SIZE, 
						       out->data + NTLMSSP_SIG_SIZE, 
						       out->length - NTLMSSP_SIG_SIZE, 
						       &sig);
		
		if (NT_STATUS_IS_OK(nt_status)) {
			memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
		}
		return nt_status;

	} else if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {

		*out = data_blob_talloc(sig_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
		if (!out->data) {
			return NT_STATUS_NO_MEMORY;
		}
		memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);

	        nt_status = gensec_ntlmssp_sign_packet(gensec_security, sig_mem_ctx, 
						       out->data + NTLMSSP_SIG_SIZE, 
						       out->length - NTLMSSP_SIG_SIZE, 
						       out->data + NTLMSSP_SIG_SIZE, 
						       out->length - NTLMSSP_SIG_SIZE, 
						       &sig);

		if (NT_STATUS_IS_OK(nt_status)) {
			memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
		}
		return nt_status;

	} else {
		*out = *in;
		return NT_STATUS_OK;
	}
}


NTSTATUS gensec_ntlmssp_unwrap(struct gensec_security *gensec_security, 
			       TALLOC_CTX *sig_mem_ctx, 
			       const DATA_BLOB *in, 
			       DATA_BLOB *out)
{
	DATA_BLOB sig;

	if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
		if (in->length < NTLMSSP_SIG_SIZE) {
			return NT_STATUS_INVALID_PARAMETER;
		}
		sig.data = in->data;
		sig.length = NTLMSSP_SIG_SIZE;

		*out = data_blob_talloc(sig_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
		
	        return gensec_ntlmssp_unseal_packet(gensec_security, sig_mem_ctx, 
						    out->data, out->length, 
						    out->data, out->length, 
						    &sig);
						  
	} else if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
		if (in->length < NTLMSSP_SIG_SIZE) {
			return NT_STATUS_INVALID_PARAMETER;
		}
		sig.data = in->data;
		sig.length = NTLMSSP_SIG_SIZE;

		*out = data_blob_talloc(sig_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
		
	        return gensec_ntlmssp_check_packet(gensec_security, sig_mem_ctx, 
						   out->data, out->length, 
						   out->data, out->length, 
						   &sig);
	} else {
		*out = *in;
		return NT_STATUS_OK;
	}
}