source: vendor/3.5.7/source3/libsmb/smb_seal.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 14.6 KB
Line 
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
22/******************************************************************************
23 Pull out the encryption context for this packet. 0 means global context.
24******************************************************************************/
25
26NTSTATUS get_enc_ctx_num(const uint8_t *buf, uint16 *p_enc_ctx_num)
27{
28 if (smb_len(buf) < 8) {
29 return NT_STATUS_INVALID_BUFFER_SIZE;
30 }
31
32 if (buf[4] == 0xFF) {
33 if (buf[5] == 'S' && buf [6] == 'M' && buf[7] == 'B') {
34 /* Not an encrypted buffer. */
35 return NT_STATUS_NOT_FOUND;
36 }
37 if (buf[5] == 'E') {
38 *p_enc_ctx_num = SVAL(buf,6);
39 return NT_STATUS_OK;
40 }
41 }
42 return NT_STATUS_INVALID_NETWORK_RESPONSE;
43}
44
45/******************************************************************************
46 Generic code for client and server.
47 Is encryption turned on ?
48******************************************************************************/
49
50bool common_encryption_on(struct smb_trans_enc_state *es)
51{
52 return ((es != NULL) && es->enc_on);
53}
54
55/******************************************************************************
56 Generic code for client and server.
57 NTLM decrypt an incoming buffer.
58 Abartlett tells me that SSPI puts the signature first before the encrypted
59 output, so cope with the same for compatibility.
60******************************************************************************/
61
62NTSTATUS common_ntlm_decrypt_buffer(NTLMSSP_STATE *ntlmssp_state, char *buf)
63{
64 NTSTATUS status;
65 size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
66 size_t data_len;
67 char *inbuf;
68 DATA_BLOB sig;
69
70 if (buf_len < 8 + NTLMSSP_SIG_SIZE) {
71 return NT_STATUS_BUFFER_TOO_SMALL;
72 }
73
74 inbuf = (char *)smb_xmemdup(buf, buf_len);
75
76 /* Adjust for the signature. */
77 data_len = buf_len - 8 - NTLMSSP_SIG_SIZE;
78
79 /* Point at the signature. */
80 sig = data_blob_const(inbuf+8, NTLMSSP_SIG_SIZE);
81
82 status = ntlmssp_unseal_packet(ntlmssp_state,
83 (unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE, /* 4 byte len + 0xFF 'E' <enc> <ctx> */
84 data_len,
85 (unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE,
86 data_len,
87 &sig);
88
89 if (!NT_STATUS_IS_OK(status)) {
90 SAFE_FREE(inbuf);
91 return status;
92 }
93
94 memcpy(buf + 8, inbuf + 8 + NTLMSSP_SIG_SIZE, data_len);
95
96 /* Reset the length and overwrite the header. */
97 smb_setlen(buf,data_len + 4);
98
99 SAFE_FREE(inbuf);
100 return NT_STATUS_OK;
101}
102
103/******************************************************************************
104 Generic code for client and server.
105 NTLM encrypt an outgoing buffer. Return the encrypted pointer in ppbuf_out.
106 Abartlett tells me that SSPI puts the signature first before the encrypted
107 output, so do the same for compatibility.
108******************************************************************************/
109
110NTSTATUS common_ntlm_encrypt_buffer(NTLMSSP_STATE *ntlmssp_state,
111 uint16 enc_ctx_num,
112 char *buf,
113 char **ppbuf_out)
114{
115 NTSTATUS status;
116 char *buf_out;
117 size_t data_len = smb_len(buf) - 4; /* Ignore the 0xFF SMB bytes. */
118 DATA_BLOB sig;
119
120 *ppbuf_out = NULL;
121
122 if (data_len == 0) {
123 return NT_STATUS_BUFFER_TOO_SMALL;
124 }
125
126 /*
127 * We know smb_len can't return a value > 128k, so no int overflow
128 * check needed.
129 */
130
131 buf_out = SMB_XMALLOC_ARRAY(char, 8 + NTLMSSP_SIG_SIZE + data_len);
132
133 /* Copy the data from the original buffer. */
134
135 memcpy(buf_out + 8 + NTLMSSP_SIG_SIZE, buf + 8, data_len);
136
137 smb_set_enclen(buf_out, smb_len(buf) + NTLMSSP_SIG_SIZE, enc_ctx_num);
138
139 ZERO_STRUCT(sig);
140
141 status = ntlmssp_seal_packet(ntlmssp_state,
142 (unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE, /* 4 byte len + 0xFF 'S' <enc> <ctx> */
143 data_len,
144 (unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE,
145 data_len,
146 &sig);
147
148 if (!NT_STATUS_IS_OK(status)) {
149 data_blob_free(&sig);
150 SAFE_FREE(buf_out);
151 return status;
152 }
153
154 /* First 16 data bytes are signature for SSPI compatibility. */
155 memcpy(buf_out + 8, sig.data, NTLMSSP_SIG_SIZE);
156 data_blob_free(&sig);
157 *ppbuf_out = buf_out;
158 return NT_STATUS_OK;
159}
160
161/******************************************************************************
162 Generic code for client and server.
163 gss-api decrypt an incoming buffer. We insist that the size of the
164 unwrapped buffer must be smaller or identical to the incoming buffer.
165******************************************************************************/
166
167#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
168static NTSTATUS common_gss_decrypt_buffer(struct smb_tran_enc_state_gss *gss_state, char *buf)
169{
170 gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
171 OM_uint32 ret = 0;
172 OM_uint32 minor = 0;
173 int flags_got = 0;
174 gss_buffer_desc in_buf, out_buf;
175 size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
176
177 if (buf_len < 8) {
178 return NT_STATUS_BUFFER_TOO_SMALL;
179 }
180
181 in_buf.value = buf + 8;
182 in_buf.length = buf_len - 8;
183
184 ret = gss_unwrap(&minor,
185 gss_ctx,
186 &in_buf,
187 &out_buf,
188 &flags_got, /* did we get sign+seal ? */
189 (gss_qop_t *) NULL);
190
191 if (ret != GSS_S_COMPLETE) {
192 ADS_STATUS adss = ADS_ERROR_GSS(ret, minor);
193 DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap failed. Error %s\n",
194 ads_errstr(adss) ));
195 return map_nt_error_from_gss(ret, minor);
196 }
197
198 if (out_buf.length > in_buf.length) {
199 DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap size (%u) too large (%u) !\n",
200 (unsigned int)out_buf.length,
201 (unsigned int)in_buf.length ));
202 gss_release_buffer(&minor, &out_buf);
203 return NT_STATUS_INVALID_PARAMETER;
204 }
205
206 memcpy(buf + 8, out_buf.value, out_buf.length);
207 /* Reset the length and overwrite the header. */
208 smb_setlen(buf, out_buf.length + 4);
209
210 gss_release_buffer(&minor, &out_buf);
211 return NT_STATUS_OK;
212}
213
214/******************************************************************************
215 Generic code for client and server.
216 gss-api encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
217******************************************************************************/
218
219static NTSTATUS common_gss_encrypt_buffer(struct smb_tran_enc_state_gss *gss_state,
220 uint16 enc_ctx_num,
221 char *buf,
222 char **ppbuf_out)
223{
224 gss_ctx_id_t gss_ctx = gss_state->gss_ctx;
225 OM_uint32 ret = 0;
226 OM_uint32 minor = 0;
227 int flags_got = 0;
228 gss_buffer_desc in_buf, out_buf;
229 size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */
230
231 *ppbuf_out = NULL;
232
233 if (buf_len < 8) {
234 return NT_STATUS_BUFFER_TOO_SMALL;
235 }
236
237 in_buf.value = buf + 8;
238 in_buf.length = buf_len - 8;
239
240 ret = gss_wrap(&minor,
241 gss_ctx,
242 true, /* we want sign+seal. */
243 GSS_C_QOP_DEFAULT,
244 &in_buf,
245 &flags_got, /* did we get sign+seal ? */
246 &out_buf);
247
248 if (ret != GSS_S_COMPLETE) {
249 ADS_STATUS adss = ADS_ERROR_GSS(ret, minor);
250 DEBUG(0,("common_gss_encrypt_buffer: gss_wrap failed. Error %s\n",
251 ads_errstr(adss) ));
252 return map_nt_error_from_gss(ret, minor);
253 }
254
255 if (!flags_got) {
256 /* Sign+seal not supported. */
257 gss_release_buffer(&minor, &out_buf);
258 return NT_STATUS_NOT_SUPPORTED;
259 }
260
261 /* Ya see - this is why I *hate* gss-api. I don't
262 * want to have to malloc another buffer of the
263 * same size + 8 bytes just to get a continuous
264 * header + buffer, but gss won't let me pass in
265 * a pre-allocated buffer. Bastards (and you know
266 * who you are....). I might fix this by
267 * going to "encrypt_and_send" passing in a file
268 * descriptor and doing scatter-gather write with
269 * TCP cork on Linux. But I shouldn't have to
270 * bother :-*(. JRA.
271 */
272
273 *ppbuf_out = (char *)SMB_MALLOC(out_buf.length + 8); /* We know this can't wrap. */
274 if (!*ppbuf_out) {
275 gss_release_buffer(&minor, &out_buf);
276 return NT_STATUS_NO_MEMORY;
277 }
278
279 memcpy(*ppbuf_out+8, out_buf.value, out_buf.length);
280 smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num);
281
282 gss_release_buffer(&minor, &out_buf);
283 return NT_STATUS_OK;
284}
285#endif
286
287/******************************************************************************
288 Generic code for client and server.
289 Encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out.
290******************************************************************************/
291
292NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state *es, char *buffer, char **buf_out)
293{
294 if (!common_encryption_on(es)) {
295 /* Not encrypting. */
296 *buf_out = buffer;
297 return NT_STATUS_OK;
298 }
299
300 switch (es->smb_enc_type) {
301 case SMB_TRANS_ENC_NTLM:
302 return common_ntlm_encrypt_buffer(es->s.ntlmssp_state, es->enc_ctx_num, buffer, buf_out);
303#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
304 case SMB_TRANS_ENC_GSS:
305 return common_gss_encrypt_buffer(es->s.gss_state, es->enc_ctx_num, buffer, buf_out);
306#endif
307 default:
308 return NT_STATUS_NOT_SUPPORTED;
309 }
310}
311
312/******************************************************************************
313 Generic code for client and server.
314 Decrypt an incoming SMB buffer. Replaces the data within it.
315 New data must be less than or equal to the current length.
316******************************************************************************/
317
318NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state *es, char *buf)
319{
320 if (!common_encryption_on(es)) {
321 /* Not decrypting. */
322 return NT_STATUS_OK;
323 }
324
325 switch (es->smb_enc_type) {
326 case SMB_TRANS_ENC_NTLM:
327 return common_ntlm_decrypt_buffer(es->s.ntlmssp_state, buf);
328#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
329 case SMB_TRANS_ENC_GSS:
330 return common_gss_decrypt_buffer(es->s.gss_state, buf);
331#endif
332 default:
333 return NT_STATUS_NOT_SUPPORTED;
334 }
335}
336
337#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
338/******************************************************************************
339 Shutdown a gss encryption state.
340******************************************************************************/
341
342static void common_free_gss_state(struct smb_tran_enc_state_gss **pp_gss_state)
343{
344 OM_uint32 minor = 0;
345 struct smb_tran_enc_state_gss *gss_state = *pp_gss_state;
346
347 if (gss_state->creds != GSS_C_NO_CREDENTIAL) {
348 gss_release_cred(&minor, &gss_state->creds);
349 }
350 if (gss_state->gss_ctx != GSS_C_NO_CONTEXT) {
351 gss_delete_sec_context(&minor, &gss_state->gss_ctx, NULL);
352 }
353 SAFE_FREE(*pp_gss_state);
354}
355#endif
356
357/******************************************************************************
358 Shutdown an encryption state.
359******************************************************************************/
360
361void common_free_encryption_state(struct smb_trans_enc_state **pp_es)
362{
363 struct smb_trans_enc_state *es = *pp_es;
364
365 if (es == NULL) {
366 return;
367 }
368
369 if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
370 if (es->s.ntlmssp_state) {
371 ntlmssp_end(&es->s.ntlmssp_state);
372 }
373 }
374#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
375 if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
376 /* Free the gss context handle. */
377 if (es->s.gss_state) {
378 common_free_gss_state(&es->s.gss_state);
379 }
380 }
381#endif
382 SAFE_FREE(es);
383 *pp_es = NULL;
384}
385
386/******************************************************************************
387 Free an encryption-allocated buffer.
388******************************************************************************/
389
390void common_free_enc_buffer(struct smb_trans_enc_state *es, char *buf)
391{
392 uint16_t enc_ctx_num;
393
394 if (!common_encryption_on(es)) {
395 return;
396 }
397
398 if (!NT_STATUS_IS_OK(get_enc_ctx_num((const uint8_t *)buf,
399 &enc_ctx_num))) {
400 return;
401 }
402
403 if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
404 SAFE_FREE(buf);
405 return;
406 }
407
408#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
409 if (es->smb_enc_type == SMB_TRANS_ENC_GSS) {
410 OM_uint32 min;
411 gss_buffer_desc rel_buf;
412 rel_buf.value = buf;
413 rel_buf.length = smb_len(buf) + 4;
414 gss_release_buffer(&min, &rel_buf);
415 }
416#endif
417}
418
419/******************************************************************************
420 Client side encryption.
421******************************************************************************/
422
423/******************************************************************************
424 Is client encryption on ?
425******************************************************************************/
426
427bool cli_encryption_on(struct cli_state *cli)
428{
429 /* If we supported multiple encrytion contexts
430 * here we'd look up based on tid.
431 */
432 return common_encryption_on(cli->trans_enc_state);
433}
434
435/******************************************************************************
436 Shutdown a client encryption state.
437******************************************************************************/
438
439void cli_free_encryption_context(struct cli_state *cli)
440{
441 common_free_encryption_state(&cli->trans_enc_state);
442}
443
444/******************************************************************************
445 Free an encryption-allocated buffer.
446******************************************************************************/
447
448void cli_free_enc_buffer(struct cli_state *cli, char *buf)
449{
450 /* We know this is an smb buffer, and we
451 * didn't malloc, only copy, for a keepalive,
452 * so ignore non-session messages. */
453
454 if(CVAL(buf,0)) {
455 return;
456 }
457
458 /* If we supported multiple encrytion contexts
459 * here we'd look up based on tid.
460 */
461 common_free_enc_buffer(cli->trans_enc_state, buf);
462}
463
464/******************************************************************************
465 Decrypt an incoming buffer.
466******************************************************************************/
467
468NTSTATUS cli_decrypt_message(struct cli_state *cli)
469{
470 NTSTATUS status;
471 uint16 enc_ctx_num;
472
473 /* Ignore non-session messages. */
474 if(CVAL(cli->inbuf,0)) {
475 return NT_STATUS_OK;
476 }
477
478 status = get_enc_ctx_num((const uint8_t *)cli->inbuf, &enc_ctx_num);
479 if (!NT_STATUS_IS_OK(status)) {
480 return status;
481 }
482
483 if (enc_ctx_num != cli->trans_enc_state->enc_ctx_num) {
484 return NT_STATUS_INVALID_HANDLE;
485 }
486
487 return common_decrypt_buffer(cli->trans_enc_state, cli->inbuf);
488}
489
490/******************************************************************************
491 Encrypt an outgoing buffer. Return the encrypted pointer in buf_out.
492******************************************************************************/
493
494NTSTATUS cli_encrypt_message(struct cli_state *cli, char *buf, char **buf_out)
495{
496 /* Ignore non-session messages. */
497 if (CVAL(buf,0)) {
498 return NT_STATUS_OK;
499 }
500
501 /* If we supported multiple encrytion contexts
502 * here we'd look up based on tid.
503 */
504 return common_encrypt_buffer(cli->trans_enc_state, buf, buf_out);
505}
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