summaryrefslogtreecommitdiff
path: root/fs/cifs/smb2misc.c
blob: 5406e95f5d922b190181d03599128f79e22d2a46 (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
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
/*
 *   fs/cifs/smb2misc.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2011
 *                 Etersoft, 2012
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *              Pavel Shilovsky (pshilovsky@samba.org) 2012
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library 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 Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/ctype.h>
#include "smb2pdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "smb2proto.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "smb2status.h"
#include "smb2glob.h"

static int
check_smb2_hdr(struct smb2_sync_hdr *shdr, __u64 mid)
{
	__u64 wire_mid = le64_to_cpu(shdr->MessageId);

	/*
	 * Make sure that this really is an SMB, that it is a response,
	 * and that the message ids match.
	 */
	if ((shdr->ProtocolId == SMB2_PROTO_NUMBER) &&
	    (mid == wire_mid)) {
		if (shdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
			return 0;
		else {
			/* only one valid case where server sends us request */
			if (shdr->Command == SMB2_OPLOCK_BREAK)
				return 0;
			else
				cifs_dbg(VFS, "Received Request not response\n");
		}
	} else { /* bad signature or mid */
		if (shdr->ProtocolId != SMB2_PROTO_NUMBER)
			cifs_dbg(VFS, "Bad protocol string signature header %x\n",
				 le32_to_cpu(shdr->ProtocolId));
		if (mid != wire_mid)
			cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
				 mid, wire_mid);
	}
	cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", wire_mid);
	return 1;
}

/*
 *  The following table defines the expected "StructureSize" of SMB2 responses
 *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS responses.
 *
 *  Note that commands are defined in smb2pdu.h in le16 but the array below is
 *  indexed by command in host byte order
 */
static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
	/* SMB2_NEGOTIATE */ cpu_to_le16(65),
	/* SMB2_SESSION_SETUP */ cpu_to_le16(9),
	/* SMB2_LOGOFF */ cpu_to_le16(4),
	/* SMB2_TREE_CONNECT */ cpu_to_le16(16),
	/* SMB2_TREE_DISCONNECT */ cpu_to_le16(4),
	/* SMB2_CREATE */ cpu_to_le16(89),
	/* SMB2_CLOSE */ cpu_to_le16(60),
	/* SMB2_FLUSH */ cpu_to_le16(4),
	/* SMB2_READ */ cpu_to_le16(17),
	/* SMB2_WRITE */ cpu_to_le16(17),
	/* SMB2_LOCK */ cpu_to_le16(4),
	/* SMB2_IOCTL */ cpu_to_le16(49),
	/* BB CHECK this ... not listed in documentation */
	/* SMB2_CANCEL */ cpu_to_le16(0),
	/* SMB2_ECHO */ cpu_to_le16(4),
	/* SMB2_QUERY_DIRECTORY */ cpu_to_le16(9),
	/* SMB2_CHANGE_NOTIFY */ cpu_to_le16(9),
	/* SMB2_QUERY_INFO */ cpu_to_le16(9),
	/* SMB2_SET_INFO */ cpu_to_le16(2),
	/* BB FIXME can also be 44 for lease break */
	/* SMB2_OPLOCK_BREAK */ cpu_to_le16(24)
};

int
smb2_check_message(char *buf, unsigned int length, struct TCP_Server_Info *srvr)
{
	struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
	struct smb2_hdr *hdr = &pdu->hdr;
	struct smb2_sync_hdr *shdr = get_sync_hdr(buf);
	__u64 mid;
	__u32 len = get_rfc1002_length(buf);
	__u32 clc_len;  /* calculated length */
	int command;

	/* BB disable following printk later */
	cifs_dbg(FYI, "%s length: 0x%x, smb_buf_length: 0x%x\n",
		 __func__, length, len);

	/*
	 * Add function to do table lookup of StructureSize by command
	 * ie Validate the wct via smb2_struct_sizes table above
	 */

	if (shdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) {
		struct smb2_transform_hdr *thdr =
			(struct smb2_transform_hdr *)buf;
		struct cifs_ses *ses = NULL;
		struct list_head *tmp;

		/* decrypt frame now that it is completely read in */
		spin_lock(&cifs_tcp_ses_lock);
		list_for_each(tmp, &srvr->smb_ses_list) {
			ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
			if (ses->Suid == thdr->SessionId)
				break;

			ses = NULL;
		}
		spin_unlock(&cifs_tcp_ses_lock);
		if (ses == NULL) {
			cifs_dbg(VFS, "no decryption - session id not found\n");
			return 1;
		}
	}

	mid = le64_to_cpu(shdr->MessageId);
	if (length < sizeof(struct smb2_pdu)) {
		if ((length >= sizeof(struct smb2_hdr))
		    && (shdr->Status != 0)) {
			pdu->StructureSize2 = 0;
			/*
			 * As with SMB/CIFS, on some error cases servers may
			 * not return wct properly
			 */
			return 0;
		} else {
			cifs_dbg(VFS, "Length less than SMB header size\n");
		}
		return 1;
	}
	if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE -
	    srvr->vals->header_preamble_size) {
		cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
			 mid);
		return 1;
	}

	if (check_smb2_hdr(shdr, mid))
		return 1;

	if (shdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
		cifs_dbg(VFS, "Illegal structure size %u\n",
			 le16_to_cpu(shdr->StructureSize));
		return 1;
	}

	command = le16_to_cpu(shdr->Command);
	if (command >= NUMBER_OF_SMB2_COMMANDS) {
		cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
		return 1;
	}

	if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
		if (command != SMB2_OPLOCK_BREAK_HE && (shdr->Status == 0 ||
		    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
			/* error packets have 9 byte structure size */
			cifs_dbg(VFS, "Illegal response size %u for command %d\n",
				 le16_to_cpu(pdu->StructureSize2), command);
			return 1;
		} else if (command == SMB2_OPLOCK_BREAK_HE
			   && (shdr->Status == 0)
			   && (le16_to_cpu(pdu->StructureSize2) != 44)
			   && (le16_to_cpu(pdu->StructureSize2) != 36)) {
			/* special case for SMB2.1 lease break message */
			cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
				 le16_to_cpu(pdu->StructureSize2));
			return 1;
		}
	}

	if (srvr->vals->header_preamble_size + len != length) {
		cifs_dbg(VFS, "Total length %u RFC1002 length %zu mismatch mid %llu\n",
			 length, srvr->vals->header_preamble_size + len, mid);
		return 1;
	}

	clc_len = smb2_calc_size(hdr);

	if (srvr->vals->header_preamble_size + len != clc_len) {
		cifs_dbg(FYI, "Calculated size %u length %zu mismatch mid %llu\n",
			 clc_len, srvr->vals->header_preamble_size + len, mid);
		/* create failed on symlink */
		if (command == SMB2_CREATE_HE &&
		    shdr->Status == STATUS_STOPPED_ON_SYMLINK)
			return 0;
		/* Windows 7 server returns 24 bytes more */
		if (clc_len + 24 - srvr->vals->header_preamble_size == len && command == SMB2_OPLOCK_BREAK_HE)
			return 0;
		/* server can return one byte more due to implied bcc[0] */
		if (clc_len == srvr->vals->header_preamble_size + len + 1)
			return 0;

		/*
		 * MacOS server pads after SMB2.1 write response with 3 bytes
		 * of junk. Other servers match RFC1001 len to actual
		 * SMB2/SMB3 frame length (header + smb2 response specific data)
		 * Log the server error (once), but allow it and continue
		 * since the frame is parseable.
		 */
		if (clc_len < srvr->vals->header_preamble_size /* RFC1001 header size */ + len) {
			printk_once(KERN_WARNING
				"SMB2 server sent bad RFC1001 len %d not %zu\n",
				len, clc_len - srvr->vals->header_preamble_size);
			return 0;
		}

		return 1;
	}
	return 0;
}

/*
 * The size of the variable area depends on the offset and length fields
 * located in different fields for various SMB2 responses. SMB2 responses
 * with no variable length info, show an offset of zero for the offset field.
 */
static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
	/* SMB2_NEGOTIATE */ true,
	/* SMB2_SESSION_SETUP */ true,
	/* SMB2_LOGOFF */ false,
	/* SMB2_TREE_CONNECT */	false,
	/* SMB2_TREE_DISCONNECT */ false,
	/* SMB2_CREATE */ true,
	/* SMB2_CLOSE */ false,
	/* SMB2_FLUSH */ false,
	/* SMB2_READ */	true,
	/* SMB2_WRITE */ false,
	/* SMB2_LOCK */	false,
	/* SMB2_IOCTL */ true,
	/* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
	/* SMB2_ECHO */ false,
	/* SMB2_QUERY_DIRECTORY */ true,
	/* SMB2_CHANGE_NOTIFY */ true,
	/* SMB2_QUERY_INFO */ true,
	/* SMB2_SET_INFO */ false,
	/* SMB2_OPLOCK_BREAK */ false
};

/*
 * Returns the pointer to the beginning of the data area. Length of the data
 * area and the offset to it (from the beginning of the smb are also returned.
 */
char *
smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
{
	struct smb2_sync_hdr *shdr = get_sync_hdr(hdr);
	*off = 0;
	*len = 0;

	/* error responses do not have data area */
	if (shdr->Status && shdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
	    (((struct smb2_err_rsp *)hdr)->StructureSize) ==
						SMB2_ERROR_STRUCTURE_SIZE2)
		return NULL;

	/*
	 * Following commands have data areas so we have to get the location
	 * of the data buffer offset and data buffer length for the particular
	 * command.
	 */
	switch (shdr->Command) {
	case SMB2_NEGOTIATE:
		*off = le16_to_cpu(
		    ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
		*len = le16_to_cpu(
		    ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
		break;
	case SMB2_SESSION_SETUP:
		*off = le16_to_cpu(
		    ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
		*len = le16_to_cpu(
		    ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
		break;
	case SMB2_CREATE:
		*off = le32_to_cpu(
		    ((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
		*len = le32_to_cpu(
		    ((struct smb2_create_rsp *)hdr)->CreateContextsLength);
		break;
	case SMB2_QUERY_INFO:
		*off = le16_to_cpu(
		    ((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
		*len = le32_to_cpu(
		    ((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
		break;
	case SMB2_READ:
		*off = ((struct smb2_read_rsp *)hdr)->DataOffset;
		*len = le32_to_cpu(((struct smb2_read_rsp *)hdr)->DataLength);
		break;
	case SMB2_QUERY_DIRECTORY:
		*off = le16_to_cpu(
		  ((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
		*len = le32_to_cpu(
		  ((struct smb2_query_directory_rsp *)hdr)->OutputBufferLength);
		break;
	case SMB2_IOCTL:
		*off = le32_to_cpu(
		  ((struct smb2_ioctl_rsp *)hdr)->OutputOffset);
		*len = le32_to_cpu(((struct smb2_ioctl_rsp *)hdr)->OutputCount);
		break;
	case SMB2_CHANGE_NOTIFY:
	default:
		/* BB FIXME for unimplemented cases above */
		cifs_dbg(VFS, "no length check for command\n");
		break;
	}

	/*
	 * Invalid length or offset probably means data area is invalid, but
	 * we have little choice but to ignore the data area in this case.
	 */
	if (*off > 4096) {
		cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
		*len = 0;
		*off = 0;
	} else if (*off < 0) {
		cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
			 *off);
		*off = 0;
		*len = 0;
	} else if (*len < 0) {
		cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
			 *len);
		*len = 0;
	} else if (*len > 128 * 1024) {
		cifs_dbg(VFS, "data area larger than 128K: %d\n", *len);
		*len = 0;
	}

	/* return pointer to beginning of data area, ie offset from SMB start */
	if ((*off != 0) && (*len != 0))
		return (char *)shdr + *off;
	else
		return NULL;
}

/*
 * Calculate the size of the SMB message based on the fixed header
 * portion, the number of word parameters and the data portion of the message.
 */
unsigned int
smb2_calc_size(void *buf)
{
	struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
	struct smb2_hdr *hdr = &pdu->hdr;
	struct smb2_sync_hdr *shdr = get_sync_hdr(hdr);
	int offset; /* the offset from the beginning of SMB to data area */
	int data_length; /* the length of the variable length data area */
	/* Structure Size has already been checked to make sure it is 64 */
	int len = 4 + le16_to_cpu(shdr->StructureSize);

	/*
	 * StructureSize2, ie length of fixed parameter area has already
	 * been checked to make sure it is the correct length.
	 */
	len += le16_to_cpu(pdu->StructureSize2);

	if (has_smb2_data_area[le16_to_cpu(shdr->Command)] == false)
		goto calc_size_exit;

	smb2_get_data_area_len(&offset, &data_length, hdr);
	cifs_dbg(FYI, "SMB2 data length %d offset %d\n", data_length, offset);

	if (data_length > 0) {
		/*
		 * Check to make sure that data area begins after fixed area,
		 * Note that last byte of the fixed area is part of data area
		 * for some commands, typically those with odd StructureSize,
		 * so we must add one to the calculation (and 4 to account for
		 * the size of the RFC1001 hdr.
		 */
		if (offset + 4 + 1 < len) {
			cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
				 offset + 4 + 1, len);
			data_length = 0;
		} else {
			len = 4 + offset + data_length;
		}
	}
calc_size_exit:
	cifs_dbg(FYI, "SMB2 len %d\n", len);
	return len;
}

/* Note: caller must free return buffer */
__le16 *
cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
{
	int len;
	const char *start_of_path;
	__le16 *to;
	int map_type;

	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
		map_type = SFM_MAP_UNI_RSVD;
	else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
		map_type = SFU_MAP_UNI_RSVD;
	else
		map_type = NO_MAP_UNI_RSVD;

	/* Windows doesn't allow paths beginning with \ */
	if (from[0] == '\\')
		start_of_path = from + 1;
	else
		start_of_path = from;
	to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
				   cifs_sb->local_nls, map_type);
	return to;
}

__le32
smb2_get_lease_state(struct cifsInodeInfo *cinode)
{
	__le32 lease = 0;

	if (CIFS_CACHE_WRITE(cinode))
		lease |= SMB2_LEASE_WRITE_CACHING;
	if (CIFS_CACHE_HANDLE(cinode))
		lease |= SMB2_LEASE_HANDLE_CACHING;
	if (CIFS_CACHE_READ(cinode))
		lease |= SMB2_LEASE_READ_CACHING;
	return lease;
}

struct smb2_lease_break_work {
	struct work_struct lease_break;
	struct tcon_link *tlink;
	__u8 lease_key[16];
	__le32 lease_state;
};

static void
cifs_ses_oplock_break(struct work_struct *work)
{
	struct smb2_lease_break_work *lw = container_of(work,
				struct smb2_lease_break_work, lease_break);
	int rc;

	rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
			      lw->lease_state);
	cifs_dbg(FYI, "Lease release rc %d\n", rc);
	cifs_put_tlink(lw->tlink);
	kfree(lw);
}

static bool
smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
		    struct smb2_lease_break_work *lw)
{
	bool found;
	__u8 lease_state;
	struct list_head *tmp;
	struct cifsFileInfo *cfile;
	struct TCP_Server_Info *server = tcon->ses->server;
	struct cifs_pending_open *open;
	struct cifsInodeInfo *cinode;
	int ack_req = le32_to_cpu(rsp->Flags &
				  SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);

	lease_state = le32_to_cpu(rsp->NewLeaseState);

	list_for_each(tmp, &tcon->openFileList) {
		cfile = list_entry(tmp, struct cifsFileInfo, tlist);
		cinode = CIFS_I(d_inode(cfile->dentry));

		if (memcmp(cinode->lease_key, rsp->LeaseKey,
							SMB2_LEASE_KEY_SIZE))
			continue;

		cifs_dbg(FYI, "found in the open list\n");
		cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
			 le32_to_cpu(rsp->NewLeaseState));

		server->ops->set_oplock_level(cinode, lease_state, 0, NULL);

		if (ack_req)
			cfile->oplock_break_cancelled = false;
		else
			cfile->oplock_break_cancelled = true;

		queue_work(cifsoplockd_wq, &cfile->oplock_break);
		kfree(lw);
		return true;
	}

	found = false;
	list_for_each_entry(open, &tcon->pending_opens, olist) {
		if (memcmp(open->lease_key, rsp->LeaseKey,
			   SMB2_LEASE_KEY_SIZE))
			continue;

		if (!found && ack_req) {
			found = true;
			memcpy(lw->lease_key, open->lease_key,
			       SMB2_LEASE_KEY_SIZE);
			lw->tlink = cifs_get_tlink(open->tlink);
			queue_work(cifsiod_wq, &lw->lease_break);
		}

		cifs_dbg(FYI, "found in the pending open list\n");
		cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
			 le32_to_cpu(rsp->NewLeaseState));

		open->oplock = lease_state;
	}
	return found;
}

static bool
smb2_is_valid_lease_break(char *buffer)
{
	struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
	struct list_head *tmp, *tmp1, *tmp2;
	struct TCP_Server_Info *server;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct smb2_lease_break_work *lw;

	lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
	if (!lw)
		return false;

	INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
	lw->lease_state = rsp->NewLeaseState;

	cifs_dbg(FYI, "Checking for lease break\n");

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &cifs_tcp_ses_list) {
		server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);

		list_for_each(tmp1, &server->smb_ses_list) {
			ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);

			list_for_each(tmp2, &ses->tcon_list) {
				tcon = list_entry(tmp2, struct cifs_tcon,
						  tcon_list);
				spin_lock(&tcon->open_file_lock);
				cifs_stats_inc(
				    &tcon->stats.cifs_stats.num_oplock_brks);
				if (smb2_tcon_has_lease(tcon, rsp, lw)) {
					spin_unlock(&tcon->open_file_lock);
					spin_unlock(&cifs_tcp_ses_lock);
					return true;
				}
				spin_unlock(&tcon->open_file_lock);
			}
		}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	kfree(lw);
	cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
	return false;
}

bool
smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
{
	struct smb2_oplock_break_rsp *rsp = (struct smb2_oplock_break_rsp *)buffer;
	struct list_head *tmp, *tmp1, *tmp2;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct cifsInodeInfo *cinode;
	struct cifsFileInfo *cfile;

	cifs_dbg(FYI, "Checking for oplock break\n");

	if (rsp->hdr.sync_hdr.Command != SMB2_OPLOCK_BREAK)
		return false;

	if (rsp->StructureSize !=
				smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
		if (le16_to_cpu(rsp->StructureSize) == 44)
			return smb2_is_valid_lease_break(buffer);
		else
			return false;
	}

	cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &server->smb_ses_list) {
		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
		list_for_each(tmp1, &ses->tcon_list) {
			tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);

			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
			spin_lock(&tcon->open_file_lock);
			list_for_each(tmp2, &tcon->openFileList) {
				cfile = list_entry(tmp2, struct cifsFileInfo,
						     tlist);
				if (rsp->PersistentFid !=
				    cfile->fid.persistent_fid ||
				    rsp->VolatileFid !=
				    cfile->fid.volatile_fid)
					continue;

				cifs_dbg(FYI, "file id match, oplock break\n");
				cinode = CIFS_I(d_inode(cfile->dentry));
				spin_lock(&cfile->file_info_lock);
				if (!CIFS_CACHE_WRITE(cinode) &&
				    rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
					cfile->oplock_break_cancelled = true;
				else
					cfile->oplock_break_cancelled = false;

				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
					&cinode->flags);

				/*
				 * Set flag if the server downgrades the oplock
				 * to L2 else clear.
				 */
				if (rsp->OplockLevel)
					set_bit(
					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
					   &cinode->flags);
				else
					clear_bit(
					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
					   &cinode->flags);
				spin_unlock(&cfile->file_info_lock);
				queue_work(cifsoplockd_wq,
					   &cfile->oplock_break);

				spin_unlock(&tcon->open_file_lock);
				spin_unlock(&cifs_tcp_ses_lock);
				return true;
			}
			spin_unlock(&tcon->open_file_lock);
			spin_unlock(&cifs_tcp_ses_lock);
			cifs_dbg(FYI, "No matching file for oplock break\n");
			return true;
		}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
	return false;
}

void
smb2_cancelled_close_fid(struct work_struct *work)
{
	struct close_cancelled_open *cancelled = container_of(work,
					struct close_cancelled_open, work);

	cifs_dbg(VFS, "Close unmatched open\n");

	SMB2_close(0, cancelled->tcon, cancelled->fid.persistent_fid,
		   cancelled->fid.volatile_fid);
	cifs_put_tcon(cancelled->tcon);
	kfree(cancelled);
}

int
smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
{
	struct smb2_sync_hdr *sync_hdr = get_sync_hdr(buffer);
	struct smb2_create_rsp *rsp = (struct smb2_create_rsp *)buffer;
	struct cifs_tcon *tcon;
	struct close_cancelled_open *cancelled;

	if (sync_hdr->Command != SMB2_CREATE ||
	    sync_hdr->Status != STATUS_SUCCESS)
		return 0;

	cancelled = kzalloc(sizeof(*cancelled), GFP_KERNEL);
	if (!cancelled)
		return -ENOMEM;

	tcon = smb2_find_smb_tcon(server, sync_hdr->SessionId,
				  sync_hdr->TreeId);
	if (!tcon) {
		kfree(cancelled);
		return -ENOENT;
	}

	cancelled->fid.persistent_fid = rsp->PersistentFileId;
	cancelled->fid.volatile_fid = rsp->VolatileFileId;
	cancelled->tcon = tcon;
	INIT_WORK(&cancelled->work, smb2_cancelled_close_fid);
	queue_work(cifsiod_wq, &cancelled->work);

	return 0;
}

#ifdef CONFIG_CIFS_SMB311
/**
 * smb311_update_preauth_hash - update @ses hash with the packet data in @iov
 *
 * Assumes @iov does not contain the rfc1002 length and iov[0] has the
 * SMB2 header.
 */
int
smb311_update_preauth_hash(struct cifs_ses *ses, struct kvec *iov, int nvec)
{
	int i, rc;
	struct sdesc *d;
	struct smb2_sync_hdr *hdr;

	if (ses->server->tcpStatus == CifsGood) {
		/* skip non smb311 connections */
		if (ses->server->dialect != SMB311_PROT_ID)
			return 0;

		/* skip last sess setup response */
		hdr = (struct smb2_sync_hdr *)iov[0].iov_base;
		if (hdr->Flags & SMB2_FLAGS_SIGNED)
			return 0;
	}

	rc = smb311_crypto_shash_allocate(ses->server);
	if (rc)
		return rc;

	d = ses->server->secmech.sdescsha512;
	rc = crypto_shash_init(&d->shash);
	if (rc) {
		cifs_dbg(VFS, "%s: could not init sha512 shash\n", __func__);
		return rc;
	}

	rc = crypto_shash_update(&d->shash, ses->preauth_sha_hash,
				 SMB2_PREAUTH_HASH_SIZE);
	if (rc) {
		cifs_dbg(VFS, "%s: could not update sha512 shash\n", __func__);
		return rc;
	}

	for (i = 0; i < nvec; i++) {
		rc = crypto_shash_update(&d->shash,
					 iov[i].iov_base, iov[i].iov_len);
		if (rc) {
			cifs_dbg(VFS, "%s: could not update sha512 shash\n",
				 __func__);
			return rc;
		}
	}

	rc = crypto_shash_final(&d->shash, ses->preauth_sha_hash);
	if (rc) {
		cifs_dbg(VFS, "%s: could not finalize sha512 shash\n",
			 __func__);
		return rc;
	}

	return 0;
}
#endif