summaryrefslogtreecommitdiff
path: root/source4/libcli/auth/ntlmssp_sign.c
blob: 2b9659ae528fff93422835207df4f922a7fb7c84 (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
/* 
 *  Unix SMB/CIFS implementation.
 *  Version 3.0
 *  NTLMSSP Signing routines
 *  Copyright (C) Luke Kenneth Casson Leighton 1996-2001
 *  Copyright (C) Andrew Bartlett 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 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"

#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 then NTLM2 code:
 *
 * This code works correctly for the sealing part of the problem.  If
 * we disable the check for valid client signatures, then we see that
 * the output of a rpcecho 'sinkdata' at smbd is correct.  We get the
 * valid data, and it is validly decrypted.
 * 
 * This means that the quantity of data passing though the RC4 sealing
 * pad is correct.  
 *
 * This code also correctly matches test values that I have obtained,
 * claiming to be the correct output of NTLM2 signature generation.
 *
 */

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, constant, strlen(constant)+1);
	MD5Final(subkey->data, &ctx3);
}

enum ntlmssp_direction {
	NTLMSSP_SEND,
	NTLMSSP_RECEIVE
};

static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *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 (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, ntlmssp_state->ntlm2_send_seq_num);
			ntlmssp_state->ntlm2_send_seq_num++;
			hmac_md5_init_limK_to_64(ntlmssp_state->send_sign_key.data, 
						 ntlmssp_state->send_sign_key.length, &ctx);
			break;
		case NTLMSSP_RECEIVE:
			SIVAL(seq_num, 0, ntlmssp_state->ntlm2_recv_seq_num);
			ntlmssp_state->ntlm2_recv_seq_num++;
			hmac_md5_init_limK_to_64(ntlmssp_state->recv_sign_key.data, 
						 ntlmssp_state->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 && ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
			switch (direction) {
			case NTLMSSP_SEND:
				arcfour_crypt_sbox(ntlmssp_state->send_seal_hash, digest, 8);
				break;
			case NTLMSSP_RECEIVE:
				arcfour_crypt_sbox(ntlmssp_state->recv_seal_hash, digest, 8);
				break;
			}
		}

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

	} else {
		uint32_t crc;
		crc = crc32_calc_buffer((const char *)data, length);
		if (!msrpc_gen(sig_mem_ctx, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlm_seq_num)) {
			return NT_STATUS_NO_MEMORY;
		}
		ntlmssp_state->ntlm_seq_num++;

		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
	}
	dump_data_pw("calculated ntlmssp signature\n", sig->data, sig->length);
	return NT_STATUS_OK;
}

NTSTATUS ntlmssp_sign_packet(struct ntlmssp_state *ntlmssp_state,
			     TALLOC_CTX *sig_mem_ctx, 
			     const uint8_t *data, size_t length, 
			     const uint8_t *whole_pdu, size_t pdu_length, 
			     DATA_BLOB *sig) 
{
	if (!ntlmssp_state->session_key.length) {
		DEBUG(3, ("NO session key, cannot check sign packet\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}
	
	if (!ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
		DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}
	
	return ntlmssp_make_packet_signature(ntlmssp_state, sig_mem_ctx, 
					     data, length, 
					     whole_pdu, pdu_length, 
					     NTLMSSP_SEND, sig, True);
}

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

NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
			      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) 
{
	DATA_BLOB local_sig;
	NTSTATUS nt_status;

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

	if (sig->length < 8) {
		DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n", 
			  (unsigned long)sig->length));
	}

	nt_status = ntlmssp_make_packet_signature(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 (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 of\n"));
			dump_data(5, local_sig.data, local_sig.length);
			
			DEBUG(5, ("BAD SIG: got signature of\n"));
			dump_data(5, sig->data, sig->length);
			
			DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
			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\n"));
			dump_data(5, (const char *)local_sig.data, local_sig.length);
			
			DEBUG(5, ("BAD SIG: got signature of\n"));
			dump_data(5, (const char *)(sig->data), sig->length);
			
			DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
			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 ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state,
			     TALLOC_CTX *sig_mem_ctx, 
			     uint8_t *data, size_t length,
			     const uint8_t *whole_pdu, size_t pdu_length, 
			     DATA_BLOB *sig)
{	
	NTSTATUS nt_status;
	if (!ntlmssp_state->session_key.length) {
		DEBUG(3, ("NO session key, cannot seal packet\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}

	if (!ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
		DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	DEBUG(10,("ntlmssp_seal_data: seal\n"));
	dump_data_pw("ntlmssp clear data\n", data, length);
	if (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(ntlmssp_state, sig_mem_ctx, 
							  data, length, 
							  whole_pdu, pdu_length, 
							  NTLMSSP_SEND, sig, False);
		arcfour_crypt_sbox(ntlmssp_state->send_seal_hash, data, length);
		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
			arcfour_crypt_sbox(ntlmssp_state->send_seal_hash, sig->data+4, 8);
		}
	} else {
		uint32_t crc;
		crc = crc32_calc_buffer((const char *)data, length);
		if (!msrpc_gen(sig_mem_ctx, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->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(ntlmssp_state->ntlmssp_hash, data, length);
		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
		/* increment counter on send */
		ntlmssp_state->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
 *
 */

NTSTATUS ntlmssp_unseal_packet(struct ntlmssp_state *ntlmssp_state,
			       TALLOC_CTX *sig_mem_ctx, 
			       uint8_t *data, size_t length,
			       const uint8_t *whole_pdu, size_t pdu_length, 
			       DATA_BLOB *sig)
{
	DATA_BLOB local_sig;
	NTSTATUS nt_status;
	if (!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 (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
		arcfour_crypt_sbox(ntlmssp_state->recv_seal_hash, data, length);

		nt_status = ntlmssp_make_packet_signature(ntlmssp_state, sig_mem_ctx, 
							  data, length, 
							  whole_pdu, pdu_length, 
							  NTLMSSP_RECEIVE, &local_sig, True);
		if (!NT_STATUS_IS_OK(nt_status)) {
			return nt_status;
		}

		if (local_sig.length != sig->length ||
		    memcmp(local_sig.data, 
			   sig->data, sig->length) != 0) {
			DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
			dump_data(5, local_sig.data, local_sig.length);
			
			DEBUG(5, ("BAD SIG: got signature of\n"));
			dump_data(5, sig->data, sig->length);
			
			DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
			return NT_STATUS_ACCESS_DENIED;
		}

		dump_data_pw("ntlmssp clear data\n", data, length);
		return NT_STATUS_OK;
	} else {
		arcfour_crypt_sbox(ntlmssp_state->ntlmssp_hash, data, length);
		dump_data_pw("ntlmssp clear data\n", data, length);
		return ntlmssp_check_packet(ntlmssp_state, sig_mem_ctx, data, length, whole_pdu, pdu_length, sig);
	}
}

/**
   Initialise the state for NTLMSSP signing.
*/
NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
{
	uint8_t p24[24];
	ZERO_STRUCT(p24);

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

	if (!ntlmssp_state->session_key.length) {
		DEBUG(3, ("NO session key, cannot intialise signing\n"));
		return NT_STATUS_NO_USER_SESSION_KEY;
	}

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

		switch (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;
		}
		
		/**
		   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.
		*/


		if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
			
		} else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
			weak_session_key.length = 6;
		} 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 */
		calc_ntlmv2_key(ntlmssp_state->mem_ctx, 
				&ntlmssp_state->send_sign_key, 
				ntlmssp_state->session_key, send_sign_const);
		dump_data_pw("NTLMSSP send sign key:\n",
			     ntlmssp_state->send_sign_key.data, 
			     ntlmssp_state->send_sign_key.length);
		
		calc_ntlmv2_key(ntlmssp_state->mem_ctx, 
				&ntlmssp_state->send_seal_key, 
				weak_session_key, send_seal_const);
		dump_data_pw("NTLMSSP send seal key:\n",
			     ntlmssp_state->send_seal_key.data, 
			     ntlmssp_state->send_seal_key.length);

		arcfour_init(ntlmssp_state->send_seal_hash, 
			     &ntlmssp_state->send_seal_key);

		dump_data_pw("NTLMSSP send sesl hash:\n", 
			     ntlmssp_state->send_seal_hash, 
			     sizeof(ntlmssp_state->send_seal_hash));

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

		calc_ntlmv2_key(ntlmssp_state->mem_ctx, 
				&ntlmssp_state->recv_seal_key, 
				weak_session_key, recv_seal_const);
		dump_data_pw("NTLMSSP recv seal key:\n",
			     ntlmssp_state->recv_seal_key.data, 
			     ntlmssp_state->recv_seal_key.length);
		arcfour_init(ntlmssp_state->recv_seal_hash, 
			     &ntlmssp_state->recv_seal_key);

		dump_data_pw("NTLMSSP receive seal hash:\n", 
			     ntlmssp_state->recv_seal_hash, 
			     sizeof(ntlmssp_state->recv_seal_hash));
	} else {
		DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));

		arcfour_init(ntlmssp_state->ntlmssp_hash, 
			     &ntlmssp_state->session_key);
		dump_data_pw("NTLMSSP hash:\n", ntlmssp_state->ntlmssp_hash,
			     sizeof(ntlmssp_state->ntlmssp_hash));
	}

	ntlmssp_state->ntlm_seq_num = 0;
	ntlmssp_state->ntlm2_send_seq_num = 0;
	ntlmssp_state->ntlm2_recv_seq_num = 0;

	return NT_STATUS_OK;
}