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DEFINITIONS
This source file includes following definitions.
- store_sequence_for_reply
- get_sequence_for_reply
- set_sequence_can_delete_flag
- cli_set_smb_signing_common
- set_smb_signing_real_common
- mark_packet_signed
- null_sign_outgoing_message
- null_check_incoming_message
- null_free_signing_context
- null_set_signing
- free_signing_context
- signing_good
- simple_packet_signature
- client_sign_outgoing_message
- client_check_incoming_message
- simple_free_signing_context
- cli_simple_set_signing
- temp_sign_outgoing_message
- temp_check_incoming_message
- temp_free_signing_context
- cli_null_set_signing
- cli_temp_set_signing
- cli_free_signing_context
- cli_calculate_sign_mac
- cli_check_sign_mac
- client_set_trans_sign_state_on
- client_set_trans_sign_state_off
- client_is_signing_on
- srv_sign_outgoing_message
- srv_check_incoming_message
- srv_oplock_set_signing
- srv_check_sign_mac
- srv_calculate_sign_mac
- srv_defer_sign_response
- srv_cancel_sign_response
- srv_set_signing_negotiated
- srv_is_signing_active
- srv_is_signing_negotiated
- srv_signing_started
- srv_set_signing
1 /*
2 Unix SMB/CIFS implementation.
3 SMB Signing Code
4 Copyright (C) Jeremy Allison 2003.
5 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include "includes.h"
22
23 /* Lookup a packet's MID (multiplex id) and figure out it's sequence number */
24 struct outstanding_packet_lookup {
25 struct outstanding_packet_lookup *prev, *next;
26 uint16 mid;
27 uint32 reply_seq_num;
28 bool can_delete; /* Set to False in trans state. */
29 };
30
31 struct smb_basic_signing_context {
32 DATA_BLOB mac_key;
33 uint32 send_seq_num;
34 struct outstanding_packet_lookup *outstanding_packet_list;
35 };
36
37 static bool store_sequence_for_reply(struct outstanding_packet_lookup **list,
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38 uint16 mid, uint32 reply_seq_num)
39 {
40 struct outstanding_packet_lookup *t;
41
42 /* Ensure we only add a mid once. */
43 for (t = *list; t; t = t->next) {
44 if (t->mid == mid) {
45 return False;
46 }
47 }
48
49 t = SMB_XMALLOC_P(struct outstanding_packet_lookup);
50 ZERO_STRUCTP(t);
51
52 t->mid = mid;
53 t->reply_seq_num = reply_seq_num;
54 t->can_delete = True;
55
56 /*
57 * Add to the *start* of the list not the end of the list.
58 * This ensures that the *last* send sequence with this mid
59 * is returned by preference.
60 * This can happen if the mid wraps and one of the early
61 * mid numbers didn't get a reply and is still lurking on
62 * the list. JRA. Found by Fran Fabrizio <fran@cis.uab.edu>.
63 */
64
65 DLIST_ADD(*list, t);
66 DEBUG(10,("store_sequence_for_reply: stored seq = %u mid = %u\n",
67 (unsigned int)reply_seq_num, (unsigned int)mid ));
68 return True;
69 }
70
71 static bool get_sequence_for_reply(struct outstanding_packet_lookup **list,
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72 uint16 mid, uint32 *reply_seq_num)
73 {
74 struct outstanding_packet_lookup *t;
75
76 for (t = *list; t; t = t->next) {
77 if (t->mid == mid) {
78 *reply_seq_num = t->reply_seq_num;
79 DEBUG(10,("get_sequence_for_reply: found seq = %u mid = %u\n",
80 (unsigned int)t->reply_seq_num, (unsigned int)t->mid ));
81 if (t->can_delete) {
82 DLIST_REMOVE(*list, t);
83 SAFE_FREE(t);
84 }
85 return True;
86 }
87 }
88 return False;
89 }
90
91 static bool set_sequence_can_delete_flag(struct outstanding_packet_lookup **list, uint16 mid, bool can_delete_entry)
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92 {
93 struct outstanding_packet_lookup *t;
94
95 for (t = *list; t; t = t->next) {
96 if (t->mid == mid) {
97 t->can_delete = can_delete_entry;
98 return True;
99 }
100 }
101 return False;
102 }
103
104 /***********************************************************
105 SMB signing - Common code before we set a new signing implementation
106 ************************************************************/
107
108 static bool cli_set_smb_signing_common(struct cli_state *cli)
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109 {
110 if (!cli->sign_info.allow_smb_signing) {
111 return False;
112 }
113
114 if (!cli->sign_info.negotiated_smb_signing
115 && !cli->sign_info.mandatory_signing) {
116 return False;
117 }
118
119 if (cli->sign_info.doing_signing) {
120 return False;
121 }
122
123 if (cli->sign_info.free_signing_context)
124 cli->sign_info.free_signing_context(&cli->sign_info);
125
126 /* These calls are INCOMPATIBLE with SMB signing */
127 cli->readbraw_supported = False;
128 cli->writebraw_supported = False;
129
130 return True;
131 }
132
133 /***********************************************************
134 SMB signing - Common code for 'real' implementations
135 ************************************************************/
136
137 static bool set_smb_signing_real_common(struct smb_sign_info *si)
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138 {
139 if (si->mandatory_signing) {
140 DEBUG(5, ("Mandatory SMB signing enabled!\n"));
141 }
142
143 si->doing_signing = True;
144 DEBUG(5, ("SMB signing enabled!\n"));
145
146 return True;
147 }
148
149 static void mark_packet_signed(char *outbuf)
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150 {
151 uint16 flags2;
152 flags2 = SVAL(outbuf,smb_flg2);
153 flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES;
154 SSVAL(outbuf,smb_flg2, flags2);
155 }
156
157 /***********************************************************
158 SMB signing - NULL implementation - calculate a MAC to send.
159 ************************************************************/
160
161 static void null_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
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162 {
163 /* we can't zero out the sig, as we might be trying to send a
164 session request - which is NBT-level, not SMB level and doesn't
165 have the field */
166 return;
167 }
168
169 /***********************************************************
170 SMB signing - NULL implementation - check a MAC sent by server.
171 ************************************************************/
172
173 static bool null_check_incoming_message(const char *inbuf,
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174 struct smb_sign_info *si,
175 bool must_be_ok)
176 {
177 return True;
178 }
179
180 /***********************************************************
181 SMB signing - NULL implementation - free signing context
182 ************************************************************/
183
184 static void null_free_signing_context(struct smb_sign_info *si)
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185 {
186 return;
187 }
188
189 /**
190 SMB signing - NULL implementation - setup the MAC key.
191
192 @note Used as an initialisation only - it will not correctly
193 shut down a real signing mechanism
194 */
195
196 static bool null_set_signing(struct smb_sign_info *si)
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197 {
198 si->signing_context = NULL;
199
200 si->sign_outgoing_message = null_sign_outgoing_message;
201 si->check_incoming_message = null_check_incoming_message;
202 si->free_signing_context = null_free_signing_context;
203
204 return True;
205 }
206
207 /**
208 * Free the signing context
209 */
210
211 static void free_signing_context(struct smb_sign_info *si)
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212 {
213 if (si->free_signing_context) {
214 si->free_signing_context(si);
215 si->signing_context = NULL;
216 }
217
218 null_set_signing(si);
219 }
220
221
222 static bool signing_good(const char *inbuf, struct smb_sign_info *si,
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223 bool good, uint32 seq, bool must_be_ok)
224 {
225 if (good) {
226
227 if (!si->doing_signing) {
228 si->doing_signing = True;
229 }
230
231 if (!si->seen_valid) {
232 si->seen_valid = True;
233 }
234
235 } else {
236 if (!si->mandatory_signing && !si->seen_valid) {
237
238 if (!must_be_ok) {
239 return True;
240 }
241 /* Non-mandatory signing - just turn off if this is the first bad packet.. */
242 DEBUG(5, ("srv_check_incoming_message: signing negotiated but not required and peer\n"
243 "isn't sending correct signatures. Turning off.\n"));
244 si->negotiated_smb_signing = False;
245 si->allow_smb_signing = False;
246 si->doing_signing = False;
247 free_signing_context(si);
248 return True;
249 } else if (!must_be_ok) {
250 /* This packet is known to be unsigned */
251 return True;
252 } else {
253 /* Mandatory signing or bad packet after signing started - fail and disconnect. */
254 if (seq)
255 DEBUG(0, ("signing_good: BAD SIG: seq %u\n", (unsigned int)seq));
256 return False;
257 }
258 }
259 return True;
260 }
261
262 /***********************************************************
263 SMB signing - Simple implementation - calculate a MAC on the packet
264 ************************************************************/
265
266 static void simple_packet_signature(struct smb_basic_signing_context *data,
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267 const uchar *buf, uint32 seq_number,
268 unsigned char calc_md5_mac[16])
269 {
270 const size_t offset_end_of_sig = (smb_ss_field + 8);
271 unsigned char sequence_buf[8];
272 struct MD5Context md5_ctx;
273 #if 0
274 /* JRA - apparently this is incorrect. */
275 unsigned char key_buf[16];
276 #endif
277
278 /*
279 * Firstly put the sequence number into the first 4 bytes.
280 * and zero out the next 4 bytes.
281 *
282 * We do this here, to avoid modifying the packet.
283 */
284
285 DEBUG(10,("simple_packet_signature: sequence number %u\n", seq_number ));
286
287 SIVAL(sequence_buf, 0, seq_number);
288 SIVAL(sequence_buf, 4, 0);
289
290 /* Calculate the 16 byte MAC - but don't alter the data in the
291 incoming packet.
292
293 This makes for a bit of fussing about, but it's not too bad.
294 */
295 MD5Init(&md5_ctx);
296
297 /* intialise with the key */
298 MD5Update(&md5_ctx, data->mac_key.data, data->mac_key.length);
299 #if 0
300 /* JRA - apparently this is incorrect. */
301 /* NB. When making and verifying SMB signatures, Windows apparently
302 zero-pads the key to 128 bits if it isn't long enough.
303 From Nalin Dahyabhai <nalin@redhat.com> */
304 if (data->mac_key.length < sizeof(key_buf)) {
305 memset(key_buf, 0, sizeof(key_buf));
306 MD5Update(&md5_ctx, key_buf, sizeof(key_buf) - data->mac_key.length);
307 }
308 #endif
309
310 /* copy in the first bit of the SMB header */
311 MD5Update(&md5_ctx, buf + 4, smb_ss_field - 4);
312
313 /* copy in the sequence number, instead of the signature */
314 MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf));
315
316 /* copy in the rest of the packet in, skipping the signature */
317 MD5Update(&md5_ctx, buf + offset_end_of_sig,
318 smb_len(buf) - (offset_end_of_sig - 4));
319
320 /* calculate the MD5 sig */
321 MD5Final(calc_md5_mac, &md5_ctx);
322 }
323
324
325 /***********************************************************
326 SMB signing - Client implementation - send the MAC.
327 ************************************************************/
328
329 static void client_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
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330 {
331 unsigned char calc_md5_mac[16];
332 struct smb_basic_signing_context *data =
333 (struct smb_basic_signing_context *)si->signing_context;
334
335 if (!si->doing_signing)
336 return;
337
338 /* JRA Paranioa test - we should be able to get rid of this... */
339 if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
340 DEBUG(1, ("client_sign_outgoing_message: Logic error. Can't check signature on short packet! smb_len = %u\n",
341 smb_len(outbuf) ));
342 abort();
343 }
344
345 /* mark the packet as signed - BEFORE we sign it...*/
346 mark_packet_signed(outbuf);
347
348 simple_packet_signature(data, (const unsigned char *)outbuf,
349 data->send_seq_num, calc_md5_mac);
350
351 DEBUG(10, ("client_sign_outgoing_message: sent SMB signature of\n"));
352 dump_data(10, calc_md5_mac, 8);
353
354 memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
355
356 /* cli->outbuf[smb_ss_field+2]=0;
357 Uncomment this to test if the remote server actually verifies signatures...*/
358
359 /* Instead of re-introducing the trans_info_conect we
360 used to have here, we use the fact that during a
361 SMBtrans/SMBtrans2/SMBnttrans send that the mid stays
362 constant. This means that calling store_sequence_for_reply()
363 will return False for all trans secondaries, as the mid is already
364 on the stored sequence list. As the send_seqence_number must
365 remain constant for all primary+secondary trans sends, we
366 only increment the send sequence number when we successfully
367 add a new entry to the outstanding sequence list. This means
368 I can isolate the fix here rather than re-adding the trans
369 signing on/off calls in libsmb/clitrans2.c JRA.
370 */
371
372 if (store_sequence_for_reply(&data->outstanding_packet_list, SVAL(outbuf,smb_mid), data->send_seq_num + 1)) {
373 data->send_seq_num += 2;
374 }
375 }
376
377 /***********************************************************
378 SMB signing - Client implementation - check a MAC sent by server.
379 ************************************************************/
380
381 static bool client_check_incoming_message(const char *inbuf,
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382 struct smb_sign_info *si,
383 bool must_be_ok)
384 {
385 bool good;
386 uint32 reply_seq_number;
387 unsigned char calc_md5_mac[16];
388 unsigned char *server_sent_mac;
389
390 struct smb_basic_signing_context *data =
391 (struct smb_basic_signing_context *)si->signing_context;
392
393 if (!si->doing_signing)
394 return True;
395
396 if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
397 DEBUG(1, ("client_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
398 return False;
399 }
400
401 if (!get_sequence_for_reply(&data->outstanding_packet_list, SVAL(inbuf, smb_mid), &reply_seq_number)) {
402 DEBUG(1, ("client_check_incoming_message: received message "
403 "with mid %u with no matching send record.\n", (unsigned int)SVAL(inbuf, smb_mid) ));
404 return False;
405 }
406
407 simple_packet_signature(data, (const unsigned char *)inbuf,
408 reply_seq_number, calc_md5_mac);
409
410 server_sent_mac = (unsigned char *)&inbuf[smb_ss_field];
411 good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
412
413 if (!good) {
414 DEBUG(5, ("client_check_incoming_message: BAD SIG: wanted SMB signature of\n"));
415 dump_data(5, calc_md5_mac, 8);
416
417 DEBUG(5, ("client_check_incoming_message: BAD SIG: got SMB signature of\n"));
418 dump_data(5, server_sent_mac, 8);
419 #if 1 /* JRATEST */
420 {
421 int i;
422 for (i = -5; i < 5; i++) {
423 simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number+i, calc_md5_mac);
424 if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
425 DEBUG(0,("client_check_incoming_message: out of seq. seq num %u matches. \
426 We were expecting seq %u\n", reply_seq_number+i, reply_seq_number ));
427 break;
428 }
429 }
430 }
431 #endif /* JRATEST */
432
433 } else {
434 DEBUG(10, ("client_check_incoming_message: seq %u: got good SMB signature of\n", (unsigned int)reply_seq_number));
435 dump_data(10, server_sent_mac, 8);
436 }
437 return signing_good(inbuf, si, good, reply_seq_number, must_be_ok);
438 }
439
440 /***********************************************************
441 SMB signing - Simple implementation - free signing context
442 ************************************************************/
443
444 static void simple_free_signing_context(struct smb_sign_info *si)
/* [<][>][^][v][top][bottom][index][help] */
445 {
446 struct smb_basic_signing_context *data =
447 (struct smb_basic_signing_context *)si->signing_context;
448 struct outstanding_packet_lookup *list;
449 struct outstanding_packet_lookup *next;
450
451 for (list = data->outstanding_packet_list; list; list = next) {
452 next = list->next;
453 DLIST_REMOVE(data->outstanding_packet_list, list);
454 SAFE_FREE(list);
455 }
456
457 data_blob_free(&data->mac_key);
458
459 SAFE_FREE(si->signing_context);
460
461 return;
462 }
463
464 /***********************************************************
465 SMB signing - Simple implementation - setup the MAC key.
466 ************************************************************/
467
468 bool cli_simple_set_signing(struct cli_state *cli,
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469 const DATA_BLOB user_session_key,
470 const DATA_BLOB response)
471 {
472 struct smb_basic_signing_context *data;
473
474 if (!user_session_key.length)
475 return False;
476
477 if (!cli_set_smb_signing_common(cli)) {
478 return False;
479 }
480
481 if (!set_smb_signing_real_common(&cli->sign_info)) {
482 return False;
483 }
484
485 data = SMB_XMALLOC_P(struct smb_basic_signing_context);
486 memset(data, '\0', sizeof(*data));
487
488 cli->sign_info.signing_context = data;
489
490 data->mac_key = data_blob(NULL, response.length + user_session_key.length);
491
492 memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length);
493
494 DEBUG(10, ("cli_simple_set_signing: user_session_key\n"));
495 dump_data(10, user_session_key.data, user_session_key.length);
496
497 if (response.length) {
498 memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length);
499 DEBUG(10, ("cli_simple_set_signing: response_data\n"));
500 dump_data(10, response.data, response.length);
501 } else {
502 DEBUG(10, ("cli_simple_set_signing: NULL response_data\n"));
503 }
504
505 dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length);
506
507 /* Initialise the sequence number */
508 data->send_seq_num = 0;
509
510 /* Initialise the list of outstanding packets */
511 data->outstanding_packet_list = NULL;
512
513 cli->sign_info.sign_outgoing_message = client_sign_outgoing_message;
514 cli->sign_info.check_incoming_message = client_check_incoming_message;
515 cli->sign_info.free_signing_context = simple_free_signing_context;
516
517 return True;
518 }
519
520 /***********************************************************
521 SMB signing - TEMP implementation - calculate a MAC to send.
522 ************************************************************/
523
524 static void temp_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
/* [<][>][^][v][top][bottom][index][help] */
525 {
526 /* mark the packet as signed - BEFORE we sign it...*/
527 mark_packet_signed(outbuf);
528
529 /* I wonder what BSRSPYL stands for - but this is what MS
530 actually sends! */
531 memcpy(&outbuf[smb_ss_field], "BSRSPYL ", 8);
532 return;
533 }
534
535 /***********************************************************
536 SMB signing - TEMP implementation - check a MAC sent by server.
537 ************************************************************/
538
539 static bool temp_check_incoming_message(const char *inbuf,
/* [<][>][^][v][top][bottom][index][help] */
540 struct smb_sign_info *si, bool foo)
541 {
542 return True;
543 }
544
545 /***********************************************************
546 SMB signing - TEMP implementation - free signing context
547 ************************************************************/
548
549 static void temp_free_signing_context(struct smb_sign_info *si)
/* [<][>][^][v][top][bottom][index][help] */
550 {
551 return;
552 }
553
554 /***********************************************************
555 SMB signing - NULL implementation - setup the MAC key.
556 ************************************************************/
557
558 bool cli_null_set_signing(struct cli_state *cli)
/* [<][>][^][v][top][bottom][index][help] */
559 {
560 return null_set_signing(&cli->sign_info);
561 }
562
563 /***********************************************************
564 SMB signing - temp implementation - setup the MAC key.
565 ************************************************************/
566
567 bool cli_temp_set_signing(struct cli_state *cli)
/* [<][>][^][v][top][bottom][index][help] */
568 {
569 if (!cli_set_smb_signing_common(cli)) {
570 return False;
571 }
572
573 cli->sign_info.signing_context = NULL;
574
575 cli->sign_info.sign_outgoing_message = temp_sign_outgoing_message;
576 cli->sign_info.check_incoming_message = temp_check_incoming_message;
577 cli->sign_info.free_signing_context = temp_free_signing_context;
578
579 return True;
580 }
581
582 void cli_free_signing_context(struct cli_state *cli)
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583 {
584 free_signing_context(&cli->sign_info);
585 }
586
587 /**
588 * Sign a packet with the current mechanism
589 */
590
591 void cli_calculate_sign_mac(struct cli_state *cli, char *buf)
/* [<][>][^][v][top][bottom][index][help] */
592 {
593 cli->sign_info.sign_outgoing_message(buf, &cli->sign_info);
594 }
595
596 /**
597 * Check a packet with the current mechanism
598 * @return False if we had an established signing connection
599 * which had a bad checksum, True otherwise.
600 */
601
602 bool cli_check_sign_mac(struct cli_state *cli, char *buf)
/* [<][>][^][v][top][bottom][index][help] */
603 {
604 if (!cli->sign_info.check_incoming_message(buf, &cli->sign_info, True)) {
605 free_signing_context(&cli->sign_info);
606 return False;
607 }
608 return True;
609 }
610
611 /***********************************************************
612 Enter trans/trans2/nttrans state.
613 ************************************************************/
614
615 bool client_set_trans_sign_state_on(struct cli_state *cli, uint16 mid)
/* [<][>][^][v][top][bottom][index][help] */
616 {
617 struct smb_sign_info *si = &cli->sign_info;
618 struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
619
620 if (!si->doing_signing) {
621 return True;
622 }
623
624 if (!data) {
625 return False;
626 }
627
628 if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, False)) {
629 return False;
630 }
631
632 return True;
633 }
634
635 /***********************************************************
636 Leave trans/trans2/nttrans state.
637 ************************************************************/
638
639 bool client_set_trans_sign_state_off(struct cli_state *cli, uint16 mid)
/* [<][>][^][v][top][bottom][index][help] */
640 {
641 uint32 reply_seq_num;
642 struct smb_sign_info *si = &cli->sign_info;
643 struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
644
645 if (!si->doing_signing) {
646 return True;
647 }
648
649 if (!data) {
650 return False;
651 }
652
653 if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, True)) {
654 return False;
655 }
656
657 /* Now delete the stored mid entry. */
658 if (!get_sequence_for_reply(&data->outstanding_packet_list, mid, &reply_seq_num)) {
659 return False;
660 }
661
662 return True;
663 }
664
665 /***********************************************************
666 Is client signing on ?
667 ************************************************************/
668
669 bool client_is_signing_on(struct cli_state *cli)
/* [<][>][^][v][top][bottom][index][help] */
670 {
671 struct smb_sign_info *si = &cli->sign_info;
672 return si->doing_signing;
673 }
674
675 /***********************************************************
676 SMB signing - Server implementation - send the MAC.
677 ************************************************************/
678
679 static void srv_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
/* [<][>][^][v][top][bottom][index][help] */
680 {
681 unsigned char calc_md5_mac[16];
682 struct smb_basic_signing_context *data =
683 (struct smb_basic_signing_context *)si->signing_context;
684 uint32 send_seq_number = data->send_seq_num-1;
685 uint16 mid;
686
687 if (!si->doing_signing) {
688 return;
689 }
690
691 /* JRA Paranioa test - we should be able to get rid of this... */
692 if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
693 DEBUG(1, ("srv_sign_outgoing_message: Logic error. Can't send signature on short packet! smb_len = %u\n",
694 smb_len(outbuf) ));
695 abort();
696 }
697
698 /* mark the packet as signed - BEFORE we sign it...*/
699 mark_packet_signed(outbuf);
700
701 mid = SVAL(outbuf, smb_mid);
702
703 /* See if this is a reply for a deferred packet. */
704 get_sequence_for_reply(&data->outstanding_packet_list, mid, &send_seq_number);
705
706 simple_packet_signature(data, (const unsigned char *)outbuf, send_seq_number, calc_md5_mac);
707
708 DEBUG(10, ("srv_sign_outgoing_message: seq %u: sent SMB signature of\n", (unsigned int)send_seq_number));
709 dump_data(10, calc_md5_mac, 8);
710
711 memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
712
713 /* cli->outbuf[smb_ss_field+2]=0;
714 Uncomment this to test if the remote client actually verifies signatures...*/
715 }
716
717 /***********************************************************
718 SMB signing - Server implementation - check a MAC sent by server.
719 ************************************************************/
720
721 static bool srv_check_incoming_message(const char *inbuf,
/* [<][>][^][v][top][bottom][index][help] */
722 struct smb_sign_info *si,
723 bool must_be_ok)
724 {
725 bool good;
726 struct smb_basic_signing_context *data =
727 (struct smb_basic_signing_context *)si->signing_context;
728 uint32 reply_seq_number = data->send_seq_num;
729 uint32 saved_seq;
730 unsigned char calc_md5_mac[16];
731 unsigned char *server_sent_mac;
732
733 if (!si->doing_signing)
734 return True;
735
736 if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
737 DEBUG(1, ("srv_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
738 return False;
739 }
740
741 /* We always increment the sequence number. */
742 data->send_seq_num += 2;
743
744 saved_seq = reply_seq_number;
745 simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number, calc_md5_mac);
746
747 server_sent_mac = (unsigned char *)&inbuf[smb_ss_field];
748 good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
749
750 if (!good) {
751
752 if (saved_seq) {
753 DEBUG(0, ("srv_check_incoming_message: BAD SIG: seq %u wanted SMB signature of\n",
754 (unsigned int)saved_seq));
755 dump_data(5, calc_md5_mac, 8);
756
757 DEBUG(0, ("srv_check_incoming_message: BAD SIG: seq %u got SMB signature of\n",
758 (unsigned int)reply_seq_number));
759 dump_data(5, server_sent_mac, 8);
760 }
761
762 #if 1 /* JRATEST */
763 {
764 int i;
765 reply_seq_number -= 5;
766 for (i = 0; i < 10; i++, reply_seq_number++) {
767 simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number, calc_md5_mac);
768 if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
769 DEBUG(0,("srv_check_incoming_message: out of seq. seq num %u matches. \
770 We were expecting seq %u\n", reply_seq_number, saved_seq ));
771 break;
772 }
773 }
774 }
775 #endif /* JRATEST */
776
777 } else {
778 DEBUG(10, ("srv_check_incoming_message: seq %u: (current is %u) got good SMB signature of\n", (unsigned int)reply_seq_number, (unsigned int)data->send_seq_num));
779 dump_data(10, server_sent_mac, 8);
780 }
781
782 return (signing_good(inbuf, si, good, saved_seq, must_be_ok));
783 }
784
785 /***********************************************************
786 SMB signing - server API's.
787 ************************************************************/
788
789 static struct smb_sign_info srv_sign_info = {
790 null_sign_outgoing_message,
791 null_check_incoming_message,
792 null_free_signing_context,
793 NULL,
794 False,
795 False,
796 False,
797 False
798 };
799
800 /***********************************************************
801 Turn signing off or on for oplock break code.
802 ************************************************************/
803
804 bool srv_oplock_set_signing(bool onoff)
/* [<][>][^][v][top][bottom][index][help] */
805 {
806 bool ret = srv_sign_info.doing_signing;
807 srv_sign_info.doing_signing = onoff;
808 return ret;
809 }
810
811 /***********************************************************
812 Called to validate an incoming packet from the client.
813 ************************************************************/
814
815 bool srv_check_sign_mac(const char *inbuf, bool must_be_ok)
/* [<][>][^][v][top][bottom][index][help] */
816 {
817 /* Check if it's a non-session message. */
818 if(CVAL(inbuf,0)) {
819 return True;
820 }
821
822 return srv_sign_info.check_incoming_message(inbuf, &srv_sign_info, must_be_ok);
823 }
824
825 /***********************************************************
826 Called to sign an outgoing packet to the client.
827 ************************************************************/
828
829 void srv_calculate_sign_mac(char *outbuf)
/* [<][>][^][v][top][bottom][index][help] */
830 {
831 /* Check if it's a non-session message. */
832 if(CVAL(outbuf,0)) {
833 return;
834 }
835
836 srv_sign_info.sign_outgoing_message(outbuf, &srv_sign_info);
837 }
838
839 /***********************************************************
840 Called by server to defer an outgoing packet.
841 ************************************************************/
842
843 void srv_defer_sign_response(uint16 mid)
/* [<][>][^][v][top][bottom][index][help] */
844 {
845 struct smb_basic_signing_context *data;
846
847 if (!srv_sign_info.doing_signing)
848 return;
849
850 data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
851
852 if (!data)
853 return;
854
855 /*
856 * Ensure we only store this mid reply once...
857 */
858
859 store_sequence_for_reply(&data->outstanding_packet_list, mid,
860 data->send_seq_num-1);
861 }
862
863 /***********************************************************
864 Called to remove sequence records when a deferred packet is
865 cancelled by mid. This should never find one....
866 ************************************************************/
867
868 void srv_cancel_sign_response(uint16 mid, bool cancel)
/* [<][>][^][v][top][bottom][index][help] */
869 {
870 struct smb_basic_signing_context *data;
871 uint32 dummy_seq;
872
873 if (!srv_sign_info.doing_signing)
874 return;
875
876 data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
877
878 if (!data)
879 return;
880
881 DEBUG(10,("srv_cancel_sign_response: for mid %u\n", (unsigned int)mid ));
882
883 while (get_sequence_for_reply(&data->outstanding_packet_list, mid, &dummy_seq))
884 ;
885
886 /* cancel doesn't send a reply so doesn't burn a sequence number. */
887 if (cancel) {
888 data->send_seq_num -= 1;
889 }
890 }
891
892 /***********************************************************
893 Called by server negprot when signing has been negotiated.
894 ************************************************************/
895
896 void srv_set_signing_negotiated(void)
/* [<][>][^][v][top][bottom][index][help] */
897 {
898 srv_sign_info.allow_smb_signing = True;
899 srv_sign_info.negotiated_smb_signing = True;
900 if (lp_server_signing() == Required)
901 srv_sign_info.mandatory_signing = True;
902
903 srv_sign_info.sign_outgoing_message = temp_sign_outgoing_message;
904 srv_sign_info.check_incoming_message = temp_check_incoming_message;
905 srv_sign_info.free_signing_context = temp_free_signing_context;
906 }
907
908 /***********************************************************
909 Returns whether signing is active. We can't use sendfile or raw
910 reads/writes if it is.
911 ************************************************************/
912
913 bool srv_is_signing_active(void)
/* [<][>][^][v][top][bottom][index][help] */
914 {
915 return srv_sign_info.doing_signing;
916 }
917
918
919 /***********************************************************
920 Returns whether signing is negotiated. We can't use it unless it was
921 in the negprot.
922 ************************************************************/
923
924 bool srv_is_signing_negotiated(void)
/* [<][>][^][v][top][bottom][index][help] */
925 {
926 return srv_sign_info.negotiated_smb_signing;
927 }
928
929 /***********************************************************
930 Returns whether signing is actually happening
931 ************************************************************/
932
933 bool srv_signing_started(void)
/* [<][>][^][v][top][bottom][index][help] */
934 {
935 struct smb_basic_signing_context *data;
936
937 if (!srv_sign_info.doing_signing) {
938 return False;
939 }
940
941 data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
942 if (!data)
943 return False;
944
945 if (data->send_seq_num == 0) {
946 return False;
947 }
948
949 return True;
950 }
951
952 /***********************************************************
953 Turn on signing from this packet onwards.
954 ************************************************************/
955
956 void srv_set_signing(const DATA_BLOB user_session_key, const DATA_BLOB response)
/* [<][>][^][v][top][bottom][index][help] */
957 {
958 struct smb_basic_signing_context *data;
959
960 if (!user_session_key.length)
961 return;
962
963 if (!srv_sign_info.negotiated_smb_signing && !srv_sign_info.mandatory_signing) {
964 DEBUG(5,("srv_set_signing: signing negotiated = %u, mandatory_signing = %u. Not allowing smb signing.\n",
965 (unsigned int)srv_sign_info.negotiated_smb_signing,
966 (unsigned int)srv_sign_info.mandatory_signing ));
967 return;
968 }
969
970 /* Once we've turned on, ignore any more sessionsetups. */
971 if (srv_sign_info.doing_signing) {
972 return;
973 }
974
975 if (srv_sign_info.free_signing_context)
976 srv_sign_info.free_signing_context(&srv_sign_info);
977
978 srv_sign_info.doing_signing = True;
979
980 data = SMB_XMALLOC_P(struct smb_basic_signing_context);
981 memset(data, '\0', sizeof(*data));
982
983 srv_sign_info.signing_context = data;
984
985 data->mac_key = data_blob(NULL, response.length + user_session_key.length);
986
987 memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length);
988 if (response.length)
989 memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length);
990
991 dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length);
992
993 DEBUG(3,("srv_set_signing: turning on SMB signing: signing negotiated = %s, mandatory_signing = %s.\n",
994 BOOLSTR(srv_sign_info.negotiated_smb_signing),
995 BOOLSTR(srv_sign_info.mandatory_signing) ));
996
997 /* Initialise the sequence number */
998 data->send_seq_num = 0;
999
1000 /* Initialise the list of outstanding packets */
1001 data->outstanding_packet_list = NULL;
1002
1003 srv_sign_info.sign_outgoing_message = srv_sign_outgoing_message;
1004 srv_sign_info.check_incoming_message = srv_check_incoming_message;
1005 srv_sign_info.free_signing_context = simple_free_signing_context;
1006 }