xref: /illumos-gate/usr/src/uts/common/fs/smbsrv/smb_locking_andx.c (revision dd72704bd9e794056c558153663c739e2012d721)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright 2020 Tintri by DDN, Inc.  All rights reserved.
25  * Copyright 2022 RackTop Systems, Inc.
26  */
27 
28 /*
29  * SMB: locking_andx
30  *
31  * SMB_COM_LOCKING_ANDX allows both locking and/or unlocking of file range(s).
32  *
33  *  Client Request                     Description
34  *  ================================== =================================
35  *
36  *  UCHAR WordCount;                   Count of parameter words = 8
37  *  UCHAR AndXCommand;                 Secondary (X) command;  0xFF = none
38  *  UCHAR AndXReserved;                Reserved (must be 0)
39  *  USHORT AndXOffset;                 Offset to next command WordCount
40  *  USHORT Fid;                        File handle
41  *  UCHAR LockType;                    See LockType table below
42  *  UCHAR OplockLevel;                 The new oplock level
43  *  ULONG Timeout;                     Milliseconds to wait for unlock
44  *  USHORT NumberOfUnlocks;            Num. unlock range structs following
45  *  USHORT NumberOfLocks;              Num. lock range structs following
46  *  USHORT ByteCount;                  Count of data bytes
47  *  LOCKING_ANDX_RANGE Unlocks[];      Unlock ranges
48  *  LOCKING_ANDX_RANGE Locks[];        Lock ranges
49  *
50  *  LockType Flag Name            Value Description
51  *  ============================  ===== ================================
52  *
53  *  LOCKING_ANDX_SHARED_LOCK      0x01  Read-only lock
54  *  LOCKING_ANDX_OPLOCK_RELEASE   0x02  Oplock break notification
55  *  LOCKING_ANDX_CHANGE_LOCKTYPE  0x04  Change lock type
56  *  LOCKING_ANDX_CANCEL_LOCK      0x08  Cancel outstanding request
57  *  LOCKING_ANDX_LARGE_FILES      0x10  Large file locking format
58  *
59  *  LOCKING_ANDX_RANGE Format
60  *  =====================================================================
61  *
62  *  USHORT Pid;                        PID of process "owning" lock
63  *  ULONG Offset;                      Offset to bytes to [un]lock
64  *  ULONG Length;                      Number of bytes to [un]lock
65  *
66  *  Large File LOCKING_ANDX_RANGE Format
67  *  =====================================================================
68  *
69  *  USHORT Pid;                        PID of process "owning" lock
70  *  USHORT Pad;                        Pad to DWORD align (mbz)
71  *  ULONG OffsetHigh;                  Offset to bytes to [un]lock
72  *                                      (high)
73  *  ULONG OffsetLow;                   Offset to bytes to [un]lock (low)
74  *  ULONG LengthHigh;                  Number of bytes to [un]lock
75  *                                      (high)
76  *  ULONG LengthLow;                   Number of bytes to [un]lock (low)
77  *
78  *  Server Response                    Description
79  *  ================================== =================================
80  *
81  *  UCHAR WordCount;                   Count of parameter words = 2
82  *  UCHAR AndXCommand;                 Secondary (X) command;  0xFF =
83  *                                      none
84  *  UCHAR AndXReserved;                Reserved (must be 0)
85  *  USHORT AndXOffset;                 Offset to next command WordCount
86  *  USHORT ByteCount;                  Count of data bytes = 0
87  *
88  * Locking is a simple mechanism for excluding other processes read/write
89  * access to regions of a file.  The locked regions can be anywhere in the
90  * logical file.  Locking beyond end-of-file is permitted.  Any process
91  * using the Fid specified in this request's Fid has access to the locked
92  * bytes, other processes will be denied the locking of the same bytes.
93  *
94  * The proper method for using locks is not to rely on being denied read or
95  * write access on any of the read/write protocols but rather to attempt
96  * the locking protocol and proceed with the read/write only if the locks
97  * succeeded.
98  *
99  * Locking a range of bytes will fail if any subranges or overlapping
100  * ranges are locked.  In other words, if any of the specified bytes are
101  * already locked, the lock will fail.
102  *
103  * If NumberOfUnlocks is non-zero, the Unlocks vector contains
104  * NumberOfUnlocks elements.  Each element requests that a lock at Offset
105  * of Length be released.  If NumberOfLocks is nonzero, the Locks vector
106  * contains NumberOfLocks elements.  Each element requests the acquisition
107  * of a lock at Offset of Length.
108  *
109  * Timeout is the maximum amount of time to wait for the byte range(s)
110  * specified to become unlocked.  A timeout value of 0 indicates that the
111  * server should fail immediately if any lock range specified is locked.  A
112  *
113  * timeout value of -1 indicates that the server should wait as long as it
114  * takes for each byte range specified to become unlocked so that it may be
115  * again locked by this protocol.  Any other value of smb_timeout specifies
116  * the maximum number of milliseconds to wait for all lock range(s)
117  * specified to become available.
118  *
119  * If any of the lock ranges timeout because of the area to be locked is
120  * already locked (or the lock fails), the other ranges in the protocol
121  * request which were successfully locked as a result of this protocol will
122  * be unlocked (either all requested ranges will be locked when this
123  * protocol returns to the client or none).
124  *
125  * If LockType has the LOCKING_ANDX_SHARED_LOCK flag set, the lock is
126  * specified as a shared lock.  Locks for both read and write (where
127  * LOCKING_ANDX_SHARED_LOCK is clear) should be prohibited, but other
128  * shared locks should be permitted.  If shared locks can not be supported
129  * by a server, the server should map the lock to a lock for both read and
130  * write.  Closing a file with locks still in force causes the locks to be
131  * released in no defined order.
132  *
133  * If LockType has the LOCKING_ANDX_LARGE_FILES flag set and if the
134  * negotiated protocol is NT LM 0.12 or later, then the Locks and Unlocks
135  * vectors are in the Large File LOCKING_ANDX_RANGE format.  This allows
136  * specification of 64 bit offsets for very large files.
137  *
138  * If the one and only member of the Locks vector has the
139  * LOCKING_ANDX_CANCEL_LOCK flag set in the LockType field, the client is
140  * requesting the server to cancel a previously requested, but not yet
141  * responded to, lock.
142  *
143  * If LockType has the LOCKING_ANDX_CHANGE_LOCKTYPE flag set, the client is
144  * requesting that the server atomically change the lock type from a shared
145  * lock to an exclusive lock or vice versa.  If the server can not do this
146  * in an atomic fashion, the server must reject this request.  NT and W95
147  * servers do not support this capability.
148  *
149  * Oplocks are described in the "Opportunistic Locks" section elsewhere in
150  * this document.  A client requests an oplock by setting the appropriate
151  * bit in the SMB_COM_OPEN_ANDX request when the file is being opened in a
152  * mode which is not exclusive.  The server responds by setting the
153  * appropriate bit in the response SMB indicating whether or not the oplock
154  * was granted.  By granting the oplock, the server tells the client the
155  * file is currently only being used by this one client process at the
156  * current time.  The client can therefore safely do read ahead and write
157  * behind as well as local caching of file locks knowing that the file will
158  * not be accessed/changed in any way by another process while the oplock
159  * is in effect.  The client will be notified when any other process
160  * attempts to open or modify the oplocked file.
161  *
162  * When another user attempts to open or otherwise modify the file which a
163  * client has oplocked, the server delays the second attempt and notifies
164  * the client via an SMB_LOCKING_ANDX SMB asynchronously sent from the
165  * server to the client.  This message has the LOCKING_ANDX_OPLOCK_RELEASE
166  * flag set indicating to the client that the oplock is being broken.
167  *
168  * OplockLevel indicates the type of oplock the client now owns. If
169  * OplockLevel is 0, the client possesses no oplocks on the file at all, if
170  * OplockLevel is 1 the client possesses a Level II oplock.  The client is
171  * expected to flush any dirty buffers to the server, submit any file locks
172  * and respond to the server with either an SMB_LOCKING_ANDX SMB having the
173  * LOCKING_ANDX_OPLOCK_RELEASE flag set, or with a file close if the file
174  * is no longer in use by the client.  If the client sends an
175  * SMB_LOCKING_ANDX SMB with the LOCKING_ANDX_OPLOCK_RELEASE flag set and
176  * NumberOfLocks is zero, the server does not send a response.  Since a
177  * close being sent to the server and break oplock notification from the
178  * server could cross on the wire, if the client gets an oplock
179  * notification on a file which it does not have open, that notification
180  * should be ignored.
181  *
182  * Due to timing, the client could get an "oplock broken" notification in a
183  * user's data buffer as a result of this notification crossing on the wire
184  * with a SMB_COM_READ_RAW request.  The client must detect this (use
185  * length of msg, "FFSMB", MID of -1 and Command of SMB_COM_LOCKING_ANDX)
186  * and honor the "oplock broken" notification as usual.  The server must
187  * also note on receipt of an SMB_COM_READ_RAW request that there is an
188  * outstanding (unanswered) "oplock broken" notification to the client and
189  * return a zero length response denoting failure of the read raw request.
190  * The client should (after responding to the "oplock broken"
191  * notification), use a standard read protocol to redo the read request.
192  * This allows a file to actually contain data matching an "oplock broken"
193  * notification and still be read correctly.
194  *
195  * The entire message sent and received including the optional second
196  * protocol must fit in the negotiated maximum transfer size.  The
197  * following are the only valid SMB commands for AndXCommand for
198  * SMB_COM_LOCKING_ANDX:
199  *
200  *     SMB_COM_READ       SMB_COM_READ_ANDX
201  *     SMB_COM_WRITE      SMB_COM_WRITE_ANDX
202  *     SMB_COM_FLUSH
203  *
204  * 4.2.6.1   Errors
205  *
206  * ERRDOS/ERRbadfile
207  * ERRDOS/ERRbadfid
208  * ERRDOS/ERRlock
209  * ERRDOS/ERRinvdevice
210  * ERRSRV/ERRinvid
211  * ERRSRV/ERRbaduid
212  */
213 
214 #include <smbsrv/smb_kproto.h>
215 
216 /*
217  * This is a somewhat arbitrary sanity limit on the length of the
218  * SMB2_LOCK_ELEMENT array.  It usually has length one or two.
219  */
220 int smb_lock_max_elem = 1024;
221 
222 smb_sdrc_t
223 smb_pre_locking_andx(smb_request_t *sr)
224 {
225 	DTRACE_SMB_START(op__LockingX, smb_request_t *, sr);
226 	return (SDRC_SUCCESS);
227 }
228 
229 void
230 smb_post_locking_andx(smb_request_t *sr)
231 {
232 	DTRACE_SMB_DONE(op__LockingX, smb_request_t *, sr);
233 }
234 
235 struct lreq {
236 	uint64_t off;
237 	uint64_t len;
238 	uint32_t pid;
239 	uint32_t reserved;
240 };
241 
242 smb_sdrc_t
243 smb_com_locking_andx(smb_request_t *sr)
244 {
245 	unsigned short	i;
246 	unsigned char	lock_type;	/* See lock_type table above */
247 	unsigned char	oplock_level;	/* The new oplock level */
248 	uint32_t	timeout;	/* Milliseconds to wait for lock */
249 	unsigned short	unlock_num;	/* # unlock range structs */
250 	unsigned short	lock_num;	/* # lock range structs */
251 	DWORD		result;
252 	int		rc;
253 	uint32_t	ltype;
254 	smb_ofile_t	*ofile;
255 	uint16_t	tmp_pid;	/* locking uses 16-bit pids */
256 	uint32_t	lrv_tot;
257 	struct lreq	*lrv_ul;
258 	struct lreq	*lrv_lk;
259 	struct lreq	*lr;
260 
261 	rc = smbsr_decode_vwv(sr, "4.wbblww", &sr->smb_fid, &lock_type,
262 	    &oplock_level, &timeout, &unlock_num, &lock_num);
263 	if (rc != 0)
264 		return (SDRC_ERROR);
265 
266 	smbsr_lookup_file(sr);
267 	if (sr->fid_ofile == NULL) {
268 		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
269 		return (SDRC_ERROR);
270 	}
271 	ofile = sr->fid_ofile;
272 	if (ofile->f_node == NULL) {
273 		smbsr_error(sr, NT_STATUS_INVALID_PARAMETER,
274 		    ERRDOS, ERROR_INVALID_PARAMETER);
275 		return (SDRC_ERROR);
276 	}
277 
278 	if (unlock_num > smb_lock_max_elem ||
279 	    lock_num > smb_lock_max_elem) {
280 		smbsr_error(sr, NT_STATUS_INSUFFICIENT_RESOURCES,
281 		    ERRDOS, ERROR_NO_SYSTEM_RESOURCES);
282 		return (SDRC_ERROR);
283 	}
284 
285 	if (lock_type & LOCKING_ANDX_SHARED_LOCK)
286 		ltype = SMB_LOCK_TYPE_READONLY;
287 	else
288 		ltype = SMB_LOCK_TYPE_READWRITE;
289 
290 	if (lock_type & LOCKING_ANDX_OPLOCK_RELEASE) {
291 		smb1_oplock_ack_break(sr, oplock_level);
292 		if (unlock_num == 0 && lock_num == 0)
293 			return (SDRC_NO_REPLY);
294 		/*
295 		 * Don't allow combining other lock/unlock actions
296 		 * with an oplock ACK (normally don't get here).
297 		 */
298 		smbsr_error(sr, NT_STATUS_INVALID_PARAMETER,
299 		    ERRDOS, ERROR_INVALID_PARAMETER);
300 		return (SDRC_ERROR);
301 	}
302 
303 	/*
304 	 * No support for changing locktype (although we could probably
305 	 * implement this)
306 	 */
307 	if (lock_type & LOCKING_ANDX_CHANGE_LOCK_TYPE) {
308 		smbsr_error(sr, 0, ERRDOS,
309 		    ERROR_ATOMIC_LOCKS_NOT_SUPPORTED);
310 		return (SDRC_ERROR);
311 	}
312 
313 	if (lock_type & LOCKING_ANDX_LARGE_FILES) {
314 		/*
315 		 * negotiated protocol should be NT LM 0.12 or later
316 		 */
317 		if (sr->session->dialect < NT_LM_0_12) {
318 			smbsr_error(sr, NT_STATUS_INVALID_PARAMETER,
319 			    ERRDOS, ERROR_INVALID_PARAMETER);
320 			return (SDRC_ERROR);
321 		}
322 	}
323 
324 	/*
325 	 * Parse the unlock, lock vectors.  Will parse all the
326 	 * unlock + lock records into one array, and then use
327 	 * pointers to the unlock and lock parts.
328 	 */
329 	lrv_tot = unlock_num + lock_num;
330 	lrv_ul = smb_srm_zalloc(sr, lrv_tot * sizeof (*lrv_ul));
331 	lrv_lk = &lrv_ul[unlock_num];
332 
333 	for (i = 0; i < lrv_tot; i++) {
334 		lr = &lrv_ul[i];
335 		if (lock_type & LOCKING_ANDX_LARGE_FILES) {
336 			rc = smb_mbc_decodef(&sr->smb_data, "w2.QQ",
337 			    &tmp_pid, &lr->off, &lr->len);
338 		} else {
339 			uint32_t	offset32, length32;
340 			rc = smb_mbc_decodef(&sr->smb_data, "wll",
341 			    &tmp_pid, &offset32, &length32);
342 			lr->off = offset32;
343 			lr->len = length32;
344 		}
345 		lr->pid = tmp_pid;	/* 16-bit PID */
346 		if (rc) {
347 			/*
348 			 * This is the error returned by Windows 2000
349 			 * even when STATUS32 has been negotiated.
350 			 */
351 			smbsr_error(sr, 0, ERRSRV, ERRerror);
352 			return (SDRC_ERROR);
353 		}
354 	}
355 
356 	/*
357 	 * Cancel waiting locks.  MS-CIFS says one place that
358 	 * this cancels all waiting locks for this FID+PID,
359 	 * but smbtorture insists this cancels just one.
360 	 * Tests with Windows 7 confirms that.
361 	 */
362 	if ((lock_type & LOCKING_ANDX_CANCEL_LOCK) != 0) {
363 		lr = lrv_lk;
364 
365 		result = smb_lock_range_cancel(sr, lr->off, lr->len, lr->pid);
366 
367 		if (result != NT_STATUS_SUCCESS) {
368 			smbsr_error(sr, 0, ERRDOS,
369 			    ERROR_CANCEL_VIOLATION);
370 			return (SDRC_ERROR);
371 		}
372 		goto out;
373 	}
374 
375 	/*
376 	 * Normal unlock and lock list
377 	 */
378 	for (i = 0; i < unlock_num; i++) {
379 		lr = &lrv_ul[i];
380 
381 		result = smb_unlock_range(sr, lr->off, lr->len, lr->pid);
382 		if (result != NT_STATUS_SUCCESS) {
383 			smbsr_error(sr, NT_STATUS_RANGE_NOT_LOCKED,
384 			    ERRDOS, ERROR_NOT_LOCKED);
385 			return (SDRC_ERROR);
386 		}
387 	}
388 	for (i = 0; i < lock_num; i++) {
389 		lr = &lrv_lk[i];
390 
391 		result = smb_lock_range(sr, lr->off, lr->len, lr->pid,
392 		    ltype, timeout);
393 		if (result != NT_STATUS_SUCCESS) {
394 			/*
395 			 * Oh... we have to rollback.
396 			 */
397 			while (i > 0) {
398 				--i;
399 				lr = &lrv_lk[i];
400 				(void) smb_unlock_range(sr,
401 				    lr->off, lr->len, lr->pid);
402 			}
403 			smb_lock_range_error(sr, result);
404 			return (SDRC_ERROR);
405 		}
406 	}
407 
408 out:
409 	if (smbsr_encode_result(sr, 2, 0, "bb.ww",
410 	    2, sr->andx_com, 0x27, 0) != 0)
411 		return (SDRC_ERROR);
412 	return (SDRC_SUCCESS);
413 }
414