summaryrefslogtreecommitdiff
path: root/source3/libsmb/smb_seal.c
blob: dde69570ab5e601350f70420aeea4e679cab23a7 (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
/* 
   Unix SMB/CIFS implementation.
   SMB Transport encryption (sealing) code.
   Copyright (C) Jeremy Allison 2007.
   
   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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

/******************************************************************************
 Pull out the encryption context for this packet. 0 means global context.
******************************************************************************/

NTSTATUS get_enc_ctx_num(char *buf, uint16 *p_enc_ctx_num)
{
	if (smb_len(buf) < 8) {
		return NT_STATUS_INVALID_BUFFER_SIZE;
	}

	if (buf[4] == (char)0xFF) {
		if (buf[5] == 'S' && buf [6] == 'M' && buf[7] == 'B') {
			/* Not an encrypted buffer. */
			return NT_STATUS_NOT_FOUND;
		}
		if (buf[5] == 'E') {
			*p_enc_ctx_num = SVAL(buf,6);
			return NT_STATUS_OK;
		}
	}
	return NT_STATUS_INVALID_NETWORK_RESPONSE;
}

/******************************************************************************
 Generic code for client and server.
 Is encryption turned on ?
******************************************************************************/

BOOL common_encryption_on(struct smb_trans_enc_state *es)
{
	return ((es != NULL) && es->enc_on);
}

/******************************************************************************
 Generic code for client and server.
 NTLM decrypt an incoming buffer.
 Abartlett tells me that SSPI puts the signature first before the encrypted
 output, so cope with the same for compatibility.
******************************************************************************/

NTSTATUS common_ntlm_decrypt_buffer(NTLMSSP_STATE *ntlmssp_state, char *buf)
{
	NTSTATUS status;
	size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
	size_t data_len;
	char *inbuf;
	DATA_BLOB sig;

	if (buf_len < 8 + NTLMSSP_SIG_SIZE) {
		return NT_STATUS_BUFFER_TOO_SMALL;
	}

	inbuf = smb_xmemdup(buf, buf_len);

	/* Adjust for the signature. */
	data_len = buf_len - 8 - NTLMSSP_SIG_SIZE;

	/* Point at the signature. */
	sig = data_blob_const(inbuf+8, NTLMSSP_SIG_SIZE);

	status = ntlmssp_unseal_packet(ntlmssp_state,
		(unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE, /* 4 byte len + 0xFF 'E' <enc> <ctx> */
		data_len,
		(unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE,
		data_len,
		&sig);

	if (!NT_STATUS_IS_OK(status)) {
		SAFE_FREE(inbuf);
		return status;
	}

	memcpy(buf + 8, inbuf + 8 + NTLMSSP_SIG_SIZE, data_len);

	/* Reset the length. */
	smb_setlen(inbuf, buf, data_len + 4);

	SAFE_FREE(inbuf);
	return NT_STATUS_OK;
}

/******************************************************************************
 Generic code for client and server.
 NTLM encrypt an outgoing buffer. Return the encrypted pointer in ppbuf_out.
 Abartlett tells me that SSPI puts the signature first before the encrypted
 output, so do the same for compatibility.
******************************************************************************/

NTSTATUS common_ntlm_encrypt_buffer(NTLMSSP_STATE *ntlmssp_state,
				uint16 enc_ctx_num,
				char *buf,
				char **ppbuf_out)
{
	NTSTATUS status;
	char *buf_out;
	size_t data_len = smb_len(buf) - 4; /* Ignore the 0xFF SMB bytes. */
	DATA_BLOB sig;

	*ppbuf_out = NULL;

	if (data_len == 0) {
		return NT_STATUS_BUFFER_TOO_SMALL;
	}

	/* 
	 * We know smb_len can't return a value > 128k, so no int overflow
	 * check needed.
	 */

	buf_out = SMB_XMALLOC_ARRAY(char, 8 + NTLMSSP_SIG_SIZE + data_len);

	/* Copy the data from the original buffer. */

	memcpy(buf_out + 8 + NTLMSSP_SIG_SIZE, buf + 8, data_len);

	smb_set_enclen(buf_out, smb_len(buf) + NTLMSSP_SIG_SIZE, enc_ctx_num);

	sig = data_blob(NULL, NTLMSSP_SIG_SIZE);

	status = ntlmssp_seal_packet(ntlmssp_state,
		(unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE, /* 4 byte len + 0xFF 'S' <enc> <ctx> */
		data_len,
		(unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE,
		data_len,
		&sig);

	if (!NT_STATUS_IS_OK(status)) {
		data_blob_free(&sig);
		SAFE_FREE(buf_out);
		return status;
	}

	/* First 16 data bytes are signature for SSPI compatibility. */
	memcpy(buf_out + 8, sig.data, NTLMSSP_SIG_SIZE);
	*ppbuf_out = buf_out;
	return NT_STATUS_OK;
}

/******************************************************************************
 Generic code for client and server.
 gss-api decrypt an incoming buffer. We insist that the size of the
 unwrapped buffer must be smaller or identical to the incoming buffer.
******************************************************************************/

#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
static NTSTATUS common_gss_decrypt_buffer(struct smb_tran_enc_state_gss *gss_state, char *buf)
{
	gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
	OM_uint32 ret = 0;
	OM_uint32 minor = 0;
	int flags_got = 0;
	gss_buffer_desc in_buf, out_buf;
	size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */

	if (buf_len < 8) {
		return NT_STATUS_BUFFER_TOO_SMALL;
	}

	in_buf.value = buf + 8;
	in_buf.length = buf_len - 8;

	ret = gss_unwrap(&minor,
			gss_ctx,
			&in_buf,
			&out_buf,
			&flags_got,		/* did we get sign+seal ? */
			(gss_qop_t *) NULL);	

	if (ret != GSS_S_COMPLETE) {
		ADS_STATUS adss = ADS_ERROR_GSS(ret, minor);
		DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap failed. Error %s\n",
			ads_errstr(adss) ));
		return map_nt_error_from_gss(ret, minor);
	}

	if (out_buf.length > in_buf.length) {
		DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap size (%u) too large (%u) !\n",
			(unsigned int)out_buf.length,
			(unsigned int)in_buf.length ));
		gss_release_buffer(&minor, &out_buf);
		return NT_STATUS_INVALID_PARAMETER;
	}

	memcpy(buf + 8, out_buf.value, out_buf.length);
	smb_setlen(out_buf.value, buf, out_buf.length + 4);

	gss_release_buffer(&minor, &out_buf);
	return NT_STATUS_OK;
}

/******************************************************************************
 Generic code for client and server.
 gss-api encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
******************************************************************************/

static NTSTATUS common_gss_encrypt_buffer(struct smb_tran_enc_state_gss *gss_state,
					uint16 enc_ctx_num,
		 			char *buf,
					char **ppbuf_out)
{
	gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
	OM_uint32 ret = 0;
	OM_uint32 minor = 0;
	int flags_got = 0;
	gss_buffer_desc in_buf, out_buf;
	size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */

	*ppbuf_out = NULL;

	if (buf_len < 8) {
		return NT_STATUS_BUFFER_TOO_SMALL;
	}

	in_buf.value = buf + 8;
	in_buf.length = buf_len - 8;

	ret = gss_wrap(&minor,
			gss_ctx,
			True,			/* we want sign+seal. */
			GSS_C_QOP_DEFAULT,
			&in_buf,
			&flags_got,		/* did we get sign+seal ? */
			&out_buf);

	if (ret != GSS_S_COMPLETE) {
		ADS_STATUS adss = ADS_ERROR_GSS(ret, minor);
		DEBUG(0,("common_gss_encrypt_buffer: gss_wrap failed. Error %s\n",
			ads_errstr(adss) ));
		return map_nt_error_from_gss(ret, minor);
	}

	if (!flags_got) {
		/* Sign+seal not supported. */
		gss_release_buffer(&minor, &out_buf);
		return NT_STATUS_NOT_SUPPORTED;
	}

	/* Ya see - this is why I *hate* gss-api. I don't 
	 * want to have to malloc another buffer of the
	 * same size + 8 bytes just to get a continuous
	 * header + buffer, but gss won't let me pass in
	 * a pre-allocated buffer. Bastards (and you know
	 * who you are....). I might fix this by
	 * going to "encrypt_and_send" passing in a file
	 * descriptor and doing scatter-gather write with
	 * TCP cork on Linux. But I shouldn't have to
	 * bother :-*(. JRA.
	 */

	*ppbuf_out = SMB_MALLOC(out_buf.length + 8); /* We know this can't wrap. */
	if (!*ppbuf_out) {
		gss_release_buffer(&minor, &out_buf);
		return NT_STATUS_NO_MEMORY;
	}

	memcpy(*ppbuf_out+8, out_buf.value, out_buf.length);
	smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num);

	gss_release_buffer(&minor, &out_buf);
	return NT_STATUS_OK;
}
#endif

/******************************************************************************
 Generic code for client and server.
 Encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
******************************************************************************/

NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state *es, char *buffer, char **buf_out)
{
	if (!common_encryption_on(es)) {
		/* Not encrypting. */
		*buf_out = buffer;
		return NT_STATUS_OK;
	}

	switch (es->smb_enc_type) {
		case SMB_TRANS_ENC_NTLM:
			return common_ntlm_encrypt_buffer(es->s.ntlmssp_state, es->enc_ctx_num, buffer, buf_out);
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
		case SMB_TRANS_ENC_GSS:
			return common_gss_encrypt_buffer(es->s.gss_state, es->enc_ctx_num, buffer, buf_out);
#endif
		default:
			return NT_STATUS_NOT_SUPPORTED;
	}
}

/******************************************************************************
 Generic code for client and server.
 Decrypt an incoming SMB buffer. Replaces the data within it.
 New data must be less than or equal to the current length.
******************************************************************************/

NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state *es, char *buf)
{
	if (!common_encryption_on(es)) {
		/* Not decrypting. */
		return NT_STATUS_OK;
	}

	switch (es->smb_enc_type) {
		case SMB_TRANS_ENC_NTLM:
			return common_ntlm_decrypt_buffer(es->s.ntlmssp_state, buf);
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
		case SMB_TRANS_ENC_GSS:
			return common_gss_decrypt_buffer(es->s.gss_state, buf);
#endif
		default:
			return NT_STATUS_NOT_SUPPORTED;
	}
}

#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
/******************************************************************************
 Shutdown a gss encryption state.
******************************************************************************/

static void common_free_gss_state(struct smb_tran_enc_state_gss **pp_gss_state)
{
	OM_uint32 minor = 0;
	struct smb_tran_enc_state_gss *gss_state = *pp_gss_state;

	if (gss_state->creds != GSS_C_NO_CREDENTIAL) {
		gss_release_cred(&minor, &gss_state->creds);
	}
	if (gss_state->gss_ctx != GSS_C_NO_CONTEXT) {
		gss_delete_sec_context(&minor, &gss_state->gss_ctx, NULL);
	}
	SAFE_FREE(*pp_gss_state);
}
#endif

/******************************************************************************
 Shutdown an encryption state.
******************************************************************************/

void common_free_encryption_state(struct smb_trans_enc_state **pp_es)
{
	struct smb_trans_enc_state *es = *pp_es;

	if (es == NULL) {
		return;
	}

	if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
		if (es->s.ntlmssp_state) {
			ntlmssp_end(&es->s.ntlmssp_state);
		}
	}
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
	if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
		/* Free the gss context handle. */
		if (es->s.gss_state) {
			common_free_gss_state(&es->s.gss_state);
		}
	}
#endif
	SAFE_FREE(es);
	*pp_es = NULL;
}

/******************************************************************************
 Free an encryption-allocated buffer.
******************************************************************************/

void common_free_enc_buffer(struct smb_trans_enc_state *es, char *buf)
{
	if (!common_encryption_on(es)) {
		return;
	}

	if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
		SAFE_FREE(buf);
		return;
	}

#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
	if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
		OM_uint32 min;
		gss_buffer_desc rel_buf;
		rel_buf.value = buf;
		rel_buf.length = smb_len(buf) + 4;
		gss_release_buffer(&min, &rel_buf);
	}
#endif
}

/******************************************************************************
 Client side encryption.
******************************************************************************/

/******************************************************************************
 Is client encryption on ?
******************************************************************************/

BOOL cli_encryption_on(struct cli_state *cli)
{
	/* If we supported multiple encrytion contexts
	 * here we'd look up based on tid.
	 */
	return common_encryption_on(cli->trans_enc_state);
}

/******************************************************************************
 Shutdown a client encryption state.
******************************************************************************/

void cli_free_encryption_context(struct cli_state *cli)
{
	common_free_encryption_state(&cli->trans_enc_state);
}

/******************************************************************************
 Free an encryption-allocated buffer.
******************************************************************************/

void cli_free_enc_buffer(struct cli_state *cli, char *buf)
{
	/* We know this is an smb buffer, and we
	 * didn't malloc, only copy, for a keepalive,
	 * so ignore session keepalives. */

	if(CVAL(buf,0) == SMBkeepalive) {
		return;
	}

	/* If we supported multiple encrytion contexts
	 * here we'd look up based on tid.
	 */
	common_free_enc_buffer(cli->trans_enc_state, buf);
}

/******************************************************************************
 Decrypt an incoming buffer.
******************************************************************************/

NTSTATUS cli_decrypt_message(struct cli_state *cli)
{
	NTSTATUS status;
	uint16 enc_ctx_num;

	/* Ignore session keepalives. */
	if(CVAL(cli->inbuf,0) == SMBkeepalive) {
		return NT_STATUS_OK;
	}

	status = get_enc_ctx_num(cli->inbuf, &enc_ctx_num);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	if (enc_ctx_num != cli->trans_enc_state->enc_ctx_num) {
		return NT_STATUS_INVALID_HANDLE;
	}

	return common_decrypt_buffer(cli->trans_enc_state, cli->inbuf);
}

/******************************************************************************
 Encrypt an outgoing buffer. Return the encrypted pointer in buf_out.
******************************************************************************/

NTSTATUS cli_encrypt_message(struct cli_state *cli, char **buf_out)
{
	/* Ignore session keepalives. */
	if(CVAL(cli->outbuf,0) == SMBkeepalive) {
		return NT_STATUS_OK;
	}

	/* If we supported multiple encrytion contexts
	 * here we'd look up based on tid.
	 */
	return common_encrypt_buffer(cli->trans_enc_state, cli->outbuf, buf_out);
}