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source: vendor/3.6.9/source3/libsmb/smb_seal.c

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Last change on this file was 740, checked in by Silvan Scherrer, 13 years ago
Samba Server: update vendor to 3.6.0
File size: 15.2 KB

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1	/*
2	Unix SMB/CIFS implementation.
3	SMB Transport encryption (sealing) code.
4	Copyright (C) Jeremy Allison 2007.
5
6	This program is free software; you can redistribute it and/or modify
7	it under the terms of the GNU General Public License as published by
8	the Free Software Foundation; either version 3 of the License, or
9	(at your option) any later version.
10
11	This program is distributed in the hope that it will be useful,
12	but WITHOUT ANY WARRANTY; without even the implied warranty of
13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	GNU General Public License for more details.
15
16	You should have received a copy of the GNU General Public License
17	along with this program. If not, see <http://www.gnu.org/licenses/>.
18	*/
19
20	#include "includes.h"
21	#include "../libcli/auth/ntlmssp.h"
22	#include "smb_crypt.h"
23	#include "libsmb/libsmb.h"
24
25	/******************************************************************************
26	Pull out the encryption context for this packet. 0 means global context.
27	******************************************************************************/
28
29	NTSTATUS get_enc_ctx_num(const uint8_t buf, uint16 p_enc_ctx_num)
30	{
31	if (smb_len(buf) < 8) {
32	return NT_STATUS_INVALID_BUFFER_SIZE;
33	}
34
35	if (buf[4] == 0xFF) {
36	if (buf[5] == 'S' && buf [6] == 'M' && buf[7] == 'B') {
37	/* Not an encrypted buffer. */
38	return NT_STATUS_NOT_FOUND;
39	}
40	if (buf[5] == 'E') {
41	*p_enc_ctx_num = SVAL(buf,6);
42	return NT_STATUS_OK;
43	}
44	}
45	return NT_STATUS_INVALID_NETWORK_RESPONSE;
46	}
47
48	/******************************************************************************
49	Generic code for client and server.
50	Is encryption turned on ?
51	******************************************************************************/
52
53	bool common_encryption_on(struct smb_trans_enc_state *es)
54	{
55	return ((es != NULL) && es->enc_on);
56	}
57
58	/******************************************************************************
59	Generic code for client and server.
60	NTLM decrypt an incoming buffer.
61	Abartlett tells me that SSPI puts the signature first before the encrypted
62	output, so cope with the same for compatibility.
63	******************************************************************************/
64
65	NTSTATUS common_ntlm_decrypt_buffer(struct ntlmssp_state ntlmssp_state, char buf)
66	{
67	NTSTATUS status;
68	size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
69	size_t data_len;
70	char *inbuf;
71	DATA_BLOB sig;
72
73	if (buf_len < 8 + NTLMSSP_SIG_SIZE) {
74	return NT_STATUS_BUFFER_TOO_SMALL;
75	}
76
77	inbuf = (char *)smb_xmemdup(buf, buf_len);
78
79	/* Adjust for the signature. */
80	data_len = buf_len - 8 - NTLMSSP_SIG_SIZE;
81
82	/* Point at the signature. */
83	sig = data_blob_const(inbuf+8, NTLMSSP_SIG_SIZE);
84
85	status = ntlmssp_unseal_packet(ntlmssp_state,
86	(unsigned char )inbuf + 8 + NTLMSSP_SIG_SIZE, / 4 byte len + 0xFF 'E' <enc> <ctx> */
87	data_len,
88	(unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE,
89	data_len,
90	&sig);
91
92	if (!NT_STATUS_IS_OK(status)) {
93	SAFE_FREE(inbuf);
94	return status;
95	}
96
97	memcpy(buf + 8, inbuf + 8 + NTLMSSP_SIG_SIZE, data_len);
98
99	/* Reset the length and overwrite the header. */
100	smb_setlen(buf,data_len + 4);
101
102	SAFE_FREE(inbuf);
103	return NT_STATUS_OK;
104	}
105
106	/******************************************************************************
107	Generic code for client and server.
108	NTLM encrypt an outgoing buffer. Return the encrypted pointer in ppbuf_out.
109	Abartlett tells me that SSPI puts the signature first before the encrypted
110	output, so do the same for compatibility.
111	******************************************************************************/
112
113	NTSTATUS common_ntlm_encrypt_buffer(struct ntlmssp_state *ntlmssp_state,
114	uint16 enc_ctx_num,
115	char *buf,
116	char **ppbuf_out)
117	{
118	NTSTATUS status;
119	char *buf_out;
120	size_t data_len = smb_len(buf) - 4; /* Ignore the 0xFF SMB bytes. */
121	DATA_BLOB sig;
122	TALLOC_CTX *frame;
123	*ppbuf_out = NULL;
124
125	if (data_len == 0) {
126	return NT_STATUS_BUFFER_TOO_SMALL;
127	}
128
129	frame = talloc_stackframe();
130	/*
131	* We know smb_len can't return a value > 128k, so no int overflow
132	* check needed.
133	*/
134
135	buf_out = SMB_XMALLOC_ARRAY(char, 8 + NTLMSSP_SIG_SIZE + data_len);
136
137	/* Copy the data from the original buffer. */
138
139	memcpy(buf_out + 8 + NTLMSSP_SIG_SIZE, buf + 8, data_len);
140
141	smb_set_enclen(buf_out, smb_len(buf) + NTLMSSP_SIG_SIZE, enc_ctx_num);
142
143	ZERO_STRUCT(sig);
144
145	status = ntlmssp_seal_packet(ntlmssp_state,
146	frame,
147	(unsigned char )buf_out + 8 + NTLMSSP_SIG_SIZE, / 4 byte len + 0xFF 'S' <enc> <ctx> */
148	data_len,
149	(unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE,
150	data_len,
151	&sig);
152
153	if (!NT_STATUS_IS_OK(status)) {
154	talloc_free(frame);
155	SAFE_FREE(buf_out);
156	return status;
157	}
158
159	/* First 16 data bytes are signature for SSPI compatibility. */
160	memcpy(buf_out + 8, sig.data, NTLMSSP_SIG_SIZE);
161	talloc_free(frame);
162	*ppbuf_out = buf_out;
163	return NT_STATUS_OK;
164	}
165
166	/******************************************************************************
167	Generic code for client and server.
168	gss-api decrypt an incoming buffer. We insist that the size of the
169	unwrapped buffer must be smaller or identical to the incoming buffer.
170	******************************************************************************/
171
172	#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
173	static NTSTATUS common_gss_decrypt_buffer(struct smb_tran_enc_state_gss gss_state, char buf)
174	{
175	gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
176	OM_uint32 ret = 0;
177	OM_uint32 minor = 0;
178	int flags_got = 0;
179	gss_buffer_desc in_buf, out_buf;
180	size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
181
182	if (buf_len < 8) {
183	return NT_STATUS_BUFFER_TOO_SMALL;
184	}
185
186	in_buf.value = buf + 8;
187	in_buf.length = buf_len - 8;
188
189	ret = gss_unwrap(&minor,
190	gss_ctx,
191	&in_buf,
192	&out_buf,
193	&flags_got, /* did we get sign+seal ? */
194	(gss_qop_t *) NULL);
195
196	if (ret != GSS_S_COMPLETE) {
197	ADS_STATUS adss = ADS_ERROR_GSS(ret, minor);
198	DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap failed. Error %s\n",
199	ads_errstr(adss) ));
200	return map_nt_error_from_gss(ret, minor);
201	}
202
203	if (out_buf.length > in_buf.length) {
204	DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap size (%u) too large (%u) !\n",
205	(unsigned int)out_buf.length,
206	(unsigned int)in_buf.length ));
207	gss_release_buffer(&minor, &out_buf);
208	return NT_STATUS_INVALID_PARAMETER;
209	}
210
211	memcpy(buf + 8, out_buf.value, out_buf.length);
212	/* Reset the length and overwrite the header. */
213	smb_setlen(buf, out_buf.length + 4);
214
215	gss_release_buffer(&minor, &out_buf);
216	return NT_STATUS_OK;
217	}
218
219	/******************************************************************************
220	Generic code for client and server.
221	gss-api encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
222	******************************************************************************/
223
224	static NTSTATUS common_gss_encrypt_buffer(struct smb_tran_enc_state_gss *gss_state,
225	uint16 enc_ctx_num,
226	char *buf,
227	char **ppbuf_out)
228	{
229	gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
230	OM_uint32 ret = 0;
231	OM_uint32 minor = 0;
232	int flags_got = 0;
233	gss_buffer_desc in_buf, out_buf;
234	size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
235
236	*ppbuf_out = NULL;
237
238	if (buf_len < 8) {
239	return NT_STATUS_BUFFER_TOO_SMALL;
240	}
241
242	in_buf.value = buf + 8;
243	in_buf.length = buf_len - 8;
244
245	ret = gss_wrap(&minor,
246	gss_ctx,
247	true, /* we want sign+seal. */
248	GSS_C_QOP_DEFAULT,
249	&in_buf,
250	&flags_got, /* did we get sign+seal ? */
251	&out_buf);
252
253	if (ret != GSS_S_COMPLETE) {
254	ADS_STATUS adss = ADS_ERROR_GSS(ret, minor);
255	DEBUG(0,("common_gss_encrypt_buffer: gss_wrap failed. Error %s\n",
256	ads_errstr(adss) ));
257	return map_nt_error_from_gss(ret, minor);
258	}
259
260	if (!flags_got) {
261	/* Sign+seal not supported. */
262	gss_release_buffer(&minor, &out_buf);
263	return NT_STATUS_NOT_SUPPORTED;
264	}
265
266	/* Ya see - this is why I hate gss-api. I don't
267	* want to have to malloc another buffer of the
268	* same size + 8 bytes just to get a continuous
269	* header + buffer, but gss won't let me pass in
270	* a pre-allocated buffer. Bastards (and you know
271	* who you are....). I might fix this by
272	* going to "encrypt_and_send" passing in a file
273	* descriptor and doing scatter-gather write with
274	* TCP cork on Linux. But I shouldn't have to
275	* bother :-*(. JRA.
276	*/
277
278	ppbuf_out = (char )SMB_MALLOC(out_buf.length + 8); /* We know this can't wrap. */
279	if (!*ppbuf_out) {
280	gss_release_buffer(&minor, &out_buf);
281	return NT_STATUS_NO_MEMORY;
282	}
283
284	memcpy(*ppbuf_out+8, out_buf.value, out_buf.length);
285	smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num);
286
287	gss_release_buffer(&minor, &out_buf);
288	return NT_STATUS_OK;
289	}
290	#endif
291
292	/******************************************************************************
293	Generic code for client and server.
294	Encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
295	******************************************************************************/
296
297	NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state es, char buffer, char **buf_out)
298	{
299	if (!common_encryption_on(es)) {
300	/* Not encrypting. */
301	*buf_out = buffer;
302	return NT_STATUS_OK;
303	}
304
305	switch (es->smb_enc_type) {
306	case SMB_TRANS_ENC_NTLM:
307	return common_ntlm_encrypt_buffer(es->s.ntlmssp_state, es->enc_ctx_num, buffer, buf_out);
308	#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
309	case SMB_TRANS_ENC_GSS:
310	return common_gss_encrypt_buffer(es->s.gss_state, es->enc_ctx_num, buffer, buf_out);
311	#endif
312	default:
313	return NT_STATUS_NOT_SUPPORTED;
314	}
315	}
316
317	/******************************************************************************
318	Generic code for client and server.
319	Decrypt an incoming SMB buffer. Replaces the data within it.
320	New data must be less than or equal to the current length.
321	******************************************************************************/
322
323	NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state es, char buf)
324	{
325	if (!common_encryption_on(es)) {
326	/* Not decrypting. */
327	return NT_STATUS_OK;
328	}
329
330	switch (es->smb_enc_type) {
331	case SMB_TRANS_ENC_NTLM:
332	return common_ntlm_decrypt_buffer(es->s.ntlmssp_state, buf);
333	#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
334	case SMB_TRANS_ENC_GSS:
335	return common_gss_decrypt_buffer(es->s.gss_state, buf);
336	#endif
337	default:
338	return NT_STATUS_NOT_SUPPORTED;
339	}
340	}
341
342	#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
343	/******************************************************************************
344	Shutdown a gss encryption state.
345	******************************************************************************/
346
347	static void common_free_gss_state(struct smb_tran_enc_state_gss **pp_gss_state)
348	{
349	OM_uint32 minor = 0;
350	struct smb_tran_enc_state_gss gss_state = pp_gss_state;
351
352	if (gss_state->creds != GSS_C_NO_CREDENTIAL) {
353	gss_release_cred(&minor, &gss_state->creds);
354	}
355	if (gss_state->gss_ctx != GSS_C_NO_CONTEXT) {
356	gss_delete_sec_context(&minor, &gss_state->gss_ctx, NULL);
357	}
358	SAFE_FREE(*pp_gss_state);
359	}
360	#endif
361
362	/******************************************************************************
363	Shutdown an encryption state.
364	******************************************************************************/
365
366	void common_free_encryption_state(struct smb_trans_enc_state **pp_es)
367	{
368	struct smb_trans_enc_state es = pp_es;
369
370	if (es == NULL) {
371	return;
372	}
373
374	if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
375	if (es->s.ntlmssp_state) {
376	TALLOC_FREE(es->s.ntlmssp_state);
377	}
378	}
379	#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
380	if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
381	/* Free the gss context handle. */
382	if (es->s.gss_state) {
383	common_free_gss_state(&es->s.gss_state);
384	}
385	}
386	#endif
387	SAFE_FREE(es);
388	*pp_es = NULL;
389	}
390
391	/******************************************************************************
392	Free an encryption-allocated buffer.
393	******************************************************************************/
394
395	void common_free_enc_buffer(struct smb_trans_enc_state es, char buf)
396	{
397	uint16_t enc_ctx_num;
398
399	if (!common_encryption_on(es)) {
400	return;
401	}
402
403	if (!NT_STATUS_IS_OK(get_enc_ctx_num((const uint8_t *)buf,
404	&enc_ctx_num))) {
405	return;
406	}
407
408	if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
409	SAFE_FREE(buf);
410	return;
411	}
412
413	#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
414	if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
415	OM_uint32 min;
416	gss_buffer_desc rel_buf;
417	rel_buf.value = buf;
418	rel_buf.length = smb_len(buf) + 4;
419	gss_release_buffer(&min, &rel_buf);
420	}
421	#endif
422	}
423
424	/******************************************************************************
425	Client side encryption.
426	******************************************************************************/
427
428	/******************************************************************************
429	Is client encryption on ?
430	******************************************************************************/
431
432	bool cli_encryption_on(struct cli_state *cli)
433	{
434	/* If we supported multiple encrytion contexts
435	* here we'd look up based on tid.
436	*/
437	return common_encryption_on(cli->trans_enc_state);
438	}
439
440	/******************************************************************************
441	Shutdown a client encryption state.
442	******************************************************************************/
443
444	void cli_free_encryption_context(struct cli_state *cli)
445	{
446	common_free_encryption_state(&cli->trans_enc_state);
447	}
448
449	/******************************************************************************
450	Free an encryption-allocated buffer.
451	******************************************************************************/
452
453	void cli_free_enc_buffer(struct cli_state cli, char buf)
454	{
455	/* We know this is an smb buffer, and we
456	* didn't malloc, only copy, for a keepalive,
457	* so ignore non-session messages. */
458
459	if(CVAL(buf,0)) {
460	return;
461	}
462
463	/* If we supported multiple encrytion contexts
464	* here we'd look up based on tid.
465	*/
466	common_free_enc_buffer(cli->trans_enc_state, buf);
467	}
468
469	/******************************************************************************
470	Decrypt an incoming buffer.
471	******************************************************************************/
472
473	NTSTATUS cli_decrypt_message(struct cli_state *cli)
474	{
475	NTSTATUS status;
476	uint16 enc_ctx_num;
477
478	/* Ignore non-session messages. */
479	if(CVAL(cli->inbuf,0)) {
480	return NT_STATUS_OK;
481	}
482
483	status = get_enc_ctx_num((const uint8_t *)cli->inbuf, &enc_ctx_num);
484	if (!NT_STATUS_IS_OK(status)) {
485	return status;
486	}
487
488	if (enc_ctx_num != cli->trans_enc_state->enc_ctx_num) {
489	return NT_STATUS_INVALID_HANDLE;
490	}
491
492	return common_decrypt_buffer(cli->trans_enc_state, cli->inbuf);
493	}
494
495	/******************************************************************************
496	Encrypt an outgoing buffer. Return the encrypted pointer in buf_out.
497	******************************************************************************/
498
499	NTSTATUS cli_encrypt_message(struct cli_state cli, char buf, char **buf_out)
500	{
501	/* Ignore non-session messages. */
502	if (CVAL(buf,0)) {
503	return NT_STATUS_OK;
504	}
505
506	/* If we supported multiple encrytion contexts
507	* here we'd look up based on tid.
508	*/
509	return common_encrypt_buffer(cli->trans_enc_state, buf, buf_out);
510	}

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