xref: /illumos-gate/usr/src/uts/common/fs/smbsrv/smb_read.c (revision 68b2bbf26c7040fea4281dcb58b81e7627e46f34)
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  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
24  */
25 
26 #include <smbsrv/smb_kproto.h>
27 #include <smbsrv/smb_fsops.h>
28 
29 /*
30  * The maximum number of bytes to return from SMB Core
31  * SmbRead or SmbLockAndRead.
32  */
33 #define	SMB_CORE_READ_MAX	4432
34 
35 /*
36  * The limit in bytes for SmbReadX.
37  */
38 #define	SMB_READX_MAX		0x10000
39 
40 int smb_common_read(smb_request_t *, smb_rw_param_t *);
41 
42 /*
43  * Read bytes from a file or named pipe (SMB Core).
44  *
45  * The requested count specifies the number of bytes desired.  Offset
46  * is limited to 32 bits, so this client request is inappropriate for
47  * files with 64 bit offsets.
48  *
49  * On return, count is the number of bytes actually being returned, which
50  * may be less than the count requested only if a read specifies bytes
51  * beyond the current file size.  In this case only the bytes that exist
52  * are returned.  A read completely beyond the end of file results in a
53  * response of length zero.  This is the only circumstance when a zero
54  * length response is generated.  A count returned which is less than the
55  * count requested is the end of file indicator.
56  */
57 smb_sdrc_t
58 smb_pre_read(smb_request_t *sr)
59 {
60 	smb_rw_param_t *param;
61 	uint32_t off_low;
62 	uint16_t count;
63 	uint16_t remcnt;
64 	int rc;
65 
66 	param = kmem_zalloc(sizeof (smb_rw_param_t), KM_SLEEP);
67 	sr->arg.rw = param;
68 
69 	rc = smbsr_decode_vwv(sr, "wwlw", &sr->smb_fid,
70 	    &count, &off_low, &remcnt);
71 
72 	param->rw_offset = (uint64_t)off_low;
73 	param->rw_count = (uint32_t)count;
74 	param->rw_mincnt = 0;
75 
76 	DTRACE_SMB_2(op__Read__start, smb_request_t *, sr,
77 	    smb_rw_param_t *, param);
78 
79 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
80 }
81 
82 void
83 smb_post_read(smb_request_t *sr)
84 {
85 	DTRACE_SMB_2(op__Read__done, smb_request_t *, sr,
86 	    smb_rw_param_t *, sr->arg.rw);
87 
88 	kmem_free(sr->arg.rw, sizeof (smb_rw_param_t));
89 }
90 
91 smb_sdrc_t
92 smb_com_read(smb_request_t *sr)
93 {
94 	smb_rw_param_t *param = sr->arg.rw;
95 	uint16_t count;
96 	int rc;
97 
98 	smbsr_lookup_file(sr);
99 	if (sr->fid_ofile == NULL) {
100 		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
101 		return (SDRC_ERROR);
102 	}
103 
104 	sr->user_cr = smb_ofile_getcred(sr->fid_ofile);
105 
106 	if (param->rw_count > SMB_CORE_READ_MAX)
107 		param->rw_count = SMB_CORE_READ_MAX;
108 
109 	if ((rc = smb_common_read(sr, param)) != 0) {
110 		smbsr_errno(sr, rc);
111 		return (SDRC_ERROR);
112 	}
113 
114 	count = (uint16_t)param->rw_count;
115 	rc = smbsr_encode_result(sr, 5, VAR_BCC, "bw8.wbwC",
116 	    5, count, VAR_BCC, 0x01, count, &sr->raw_data);
117 
118 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
119 }
120 
121 /*
122  * Lock and read bytes from a file (SMB Core Plus).  The SmbLockAndRead/
123  * SmbLockAndWrite sub-dialect is only valid on disk files: reject any
124  * attempt to use it on non-disk shares.
125  *
126  * The requested count specifies the number of bytes desired.  Offset
127  * specifies the offset in the file of the first byte to be locked then
128  * read. Note that offset is limited to 32 bits, so this client request
129  * is inappropriate for files with 64 bit offsets.
130  *
131  * As with SMB_LOCK_BYTE_RANGE request, if the lock cannot be granted
132  * immediately an error should be returned to the client.  If an error
133  * occurs on the lock, the bytes should not be read.
134  *
135  * On return, count is the number of bytes actually being returned, which
136  * may be less than the count requested only if a read specifies bytes
137  * beyond the current file size.  In this case only the bytes that exist
138  * are returned.  A read completely beyond the end of file results in a
139  * response of length zero.  This is the only circumstance when a zero
140  * length response is generated.  A count returned which is less than the
141  * count requested is the end of file indicator.
142  */
143 smb_sdrc_t
144 smb_pre_lock_and_read(smb_request_t *sr)
145 {
146 	smb_rw_param_t *param;
147 	uint32_t off_low;
148 	uint16_t count;
149 	uint16_t remcnt;
150 	int rc;
151 
152 	param = kmem_zalloc(sizeof (smb_rw_param_t), KM_SLEEP);
153 	sr->arg.rw = param;
154 
155 	rc = smbsr_decode_vwv(sr, "wwlw", &sr->smb_fid,
156 	    &count, &off_low, &remcnt);
157 
158 	param->rw_offset = (uint64_t)off_low;
159 	param->rw_count = (uint32_t)count;
160 	param->rw_mincnt = 0;
161 
162 	DTRACE_SMB_2(op__LockAndRead__start, smb_request_t *, sr,
163 	    smb_rw_param_t *, param);
164 
165 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
166 }
167 
168 void
169 smb_post_lock_and_read(smb_request_t *sr)
170 {
171 	DTRACE_SMB_2(op__LockAndRead__done, smb_request_t *, sr,
172 	    smb_rw_param_t *, sr->arg.rw);
173 
174 	kmem_free(sr->arg.rw, sizeof (smb_rw_param_t));
175 }
176 
177 smb_sdrc_t
178 smb_com_lock_and_read(smb_request_t *sr)
179 {
180 	smb_rw_param_t *param = sr->arg.rw;
181 	DWORD status;
182 	uint16_t count;
183 	int rc;
184 
185 	if (STYPE_ISDSK(sr->tid_tree->t_res_type) == 0) {
186 		smbsr_error(sr, NT_STATUS_ACCESS_DENIED, ERRDOS, ERRnoaccess);
187 		return (SDRC_ERROR);
188 	}
189 
190 	smbsr_lookup_file(sr);
191 	if (sr->fid_ofile == NULL) {
192 		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
193 		return (SDRC_ERROR);
194 	}
195 
196 	sr->user_cr = smb_ofile_getcred(sr->fid_ofile);
197 
198 	status = smb_lock_range(sr, param->rw_offset, (uint64_t)param->rw_count,
199 	    0, SMB_LOCK_TYPE_READWRITE);
200 
201 	if (status != NT_STATUS_SUCCESS) {
202 		smb_lock_range_error(sr, status);
203 		return (SDRC_ERROR);
204 	}
205 
206 	if (param->rw_count > SMB_CORE_READ_MAX)
207 		param->rw_count = SMB_CORE_READ_MAX;
208 
209 	if ((rc = smb_common_read(sr, param)) != 0) {
210 		smbsr_errno(sr, rc);
211 		return (SDRC_ERROR);
212 	}
213 
214 	count = (uint16_t)param->rw_count;
215 	rc = smbsr_encode_result(sr, 5, VAR_BCC, "bw8.wbwC",
216 	    5, count, VAR_BCC, 0x1, count, &sr->raw_data);
217 
218 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
219 }
220 
221 /*
222  * Read bytes from a file (SMB Core).  This request was extended in
223  * LM 0.12 to support 64-bit offsets, indicated by sending a wct of
224  * 12 and including additional offset information.
225  *
226  * MS-SMB 3.3.5.7 update to LM 0.12 4.2.4:
227  * If wct is 12 and CAP_LARGE_READX is set, the count may be larger
228  * than the negotiated buffer size.  If maxcnt_high is 0xFF, it must
229  * be ignored.  Otherwise, maxcnt_high represents the upper 16 bits
230  * of rw_count.
231  */
232 smb_sdrc_t
233 smb_pre_read_andx(smb_request_t *sr)
234 {
235 	smb_rw_param_t *param;
236 	uint32_t off_low;
237 	uint32_t off_high;
238 	uint32_t maxcnt_high;
239 	uint16_t maxcnt_low;
240 	uint16_t mincnt;
241 	uint16_t remcnt;
242 	int rc;
243 
244 	param = kmem_zalloc(sizeof (smb_rw_param_t), KM_SLEEP);
245 	sr->arg.rw = param;
246 
247 	if (sr->smb_wct == 12) {
248 		rc = smbsr_decode_vwv(sr, "b3.wlwwlwl", &param->rw_andx,
249 		    &sr->smb_fid, &off_low, &maxcnt_low, &mincnt, &maxcnt_high,
250 		    &remcnt, &off_high);
251 
252 		param->rw_offset = ((uint64_t)off_high << 32) |
253 		    (uint64_t)off_low;
254 
255 		param->rw_count = (uint32_t)maxcnt_low;
256 
257 		if ((sr->session->capabilities & CAP_LARGE_READX) &&
258 		    (maxcnt_high < 0xFF))
259 			param->rw_count |= maxcnt_high << 16;
260 	} else {
261 		rc = smbsr_decode_vwv(sr, "b3.wlwwlw", &param->rw_andx,
262 		    &sr->smb_fid, &off_low, &maxcnt_low, &mincnt, &maxcnt_high,
263 		    &remcnt);
264 
265 		param->rw_offset = (uint64_t)off_low;
266 		param->rw_count = (uint32_t)maxcnt_low;
267 	}
268 
269 	param->rw_mincnt = 0;
270 
271 	DTRACE_SMB_2(op__ReadX__start, smb_request_t *, sr,
272 	    smb_rw_param_t *, param);
273 
274 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
275 }
276 
277 void
278 smb_post_read_andx(smb_request_t *sr)
279 {
280 	DTRACE_SMB_2(op__ReadX__done, smb_request_t *, sr,
281 	    smb_rw_param_t *, sr->arg.rw);
282 
283 	kmem_free(sr->arg.rw, sizeof (smb_rw_param_t));
284 }
285 
286 smb_sdrc_t
287 smb_com_read_andx(smb_request_t *sr)
288 {
289 	smb_rw_param_t *param = sr->arg.rw;
290 	uint16_t datalen_high;
291 	uint16_t datalen_low;
292 	uint16_t data_offset;
293 	uint16_t offset2;
294 	int rc;
295 
296 	smbsr_lookup_file(sr);
297 	if (sr->fid_ofile == NULL) {
298 		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
299 		return (SDRC_ERROR);
300 	}
301 
302 	sr->user_cr = smb_ofile_getcred(sr->fid_ofile);
303 
304 	if (param->rw_count >= SMB_READX_MAX)
305 		param->rw_count = 0;
306 
307 	if ((rc = smb_common_read(sr, param)) != 0) {
308 		smbsr_errno(sr, rc);
309 		return (SDRC_ERROR);
310 	}
311 
312 	datalen_low = param->rw_count & 0xFFFF;
313 	datalen_high = (param->rw_count >> 16) & 0xFF;
314 
315 	/*
316 	 * If this is a secondary command, the data offset
317 	 * includes the previous wct + sizeof(wct).
318 	 */
319 	data_offset = (sr->andx_prev_wct == 0) ? 0 : sr->andx_prev_wct + 1;
320 
321 	if (STYPE_ISIPC(sr->tid_tree->t_res_type)) {
322 		data_offset += 60;
323 		offset2 = (param->rw_andx == 0xFF) ? 0 : param->rw_count + 60;
324 
325 		rc = smbsr_encode_result(sr, 12, VAR_BCC, "bb1.ww4.www8.wbC",
326 		    12,			/* wct */
327 		    param->rw_andx,	/* secondary andx command */
328 		    offset2,		/* offset to next command */
329 		    0,			/* set to 0 for named pipes */
330 		    datalen_low,	/* data byte count */
331 		    data_offset,	/* offset from start to data */
332 		    datalen_high,	/* data byte count */
333 		    VAR_BCC,		/* BCC marker */
334 		    0x00,		/* padding */
335 		    &sr->raw_data);
336 	} else {
337 		data_offset += 59;
338 		offset2 = (param->rw_andx == 0xFF) ? 0 : param->rw_count + 59;
339 
340 		rc = smbsr_encode_result(sr, 12, VAR_BCC, "bb1.ww4.www8.wC",
341 		    12,			/* wct */
342 		    param->rw_andx,	/* secondary andx command */
343 		    offset2,		/* offset to next command */
344 		    -1,			/* must be -1 for regular files */
345 		    datalen_low,	/* data byte count */
346 		    data_offset,	/* offset from start to data */
347 		    datalen_high,	/* data byte count */
348 		    VAR_BCC,		/* BCC marker */
349 		    &sr->raw_data);
350 	}
351 
352 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
353 }
354 
355 /*
356  * Common function for reading files or IPC/MSRPC named pipes.  All
357  * protocol read functions should lookup the fid before calling this
358  * function.  We can't move the fid lookup here because lock-and-read
359  * requires the fid to do locking before attempting the read.
360  *
361  * Reading from a file should break oplocks on the file to LEVEL_II.
362  * A call to smb_oplock_break(SMB_OPLOCK_BREAK_TO_LEVEL_II) is not
363  * required as it is a no-op. If there's anything greater than a
364  * LEVEL_II oplock on the file, the oplock MUST be owned by the ofile
365  * on which the read is occuring and therefore would not be broken.
366  *
367  * Returns errno values.
368  */
369 int
370 smb_common_read(smb_request_t *sr, smb_rw_param_t *param)
371 {
372 	smb_ofile_t *ofile = sr->fid_ofile;
373 	smb_node_t *node;
374 	smb_vdb_t *vdb = &param->rw_vdb;
375 	struct mbuf *top;
376 	int rc;
377 
378 	vdb->vdb_tag = 0;
379 	vdb->vdb_uio.uio_iov = &vdb->vdb_iovec[0];
380 	vdb->vdb_uio.uio_iovcnt = MAX_IOVEC;
381 	vdb->vdb_uio.uio_resid = param->rw_count;
382 	vdb->vdb_uio.uio_loffset = (offset_t)param->rw_offset;
383 	vdb->vdb_uio.uio_segflg = UIO_SYSSPACE;
384 	vdb->vdb_uio.uio_extflg = UIO_COPY_DEFAULT;
385 
386 	switch (sr->tid_tree->t_res_type & STYPE_MASK) {
387 	case STYPE_DISKTREE:
388 		node = ofile->f_node;
389 
390 		if (!smb_node_is_dir(node)) {
391 			rc = smb_lock_range_access(sr, node, param->rw_offset,
392 			    param->rw_count, B_FALSE);
393 			if (rc != NT_STATUS_SUCCESS) {
394 				rc = ERANGE;
395 				break;
396 			}
397 		}
398 
399 		if ((ofile->f_flags & SMB_OFLAGS_EXECONLY) &&
400 		    !(sr->smb_flg2 & SMB_FLAGS2_READ_IF_EXECUTE)) {
401 			/*
402 			 * SMB_FLAGS2_READ_IF_EXECUTE: permit execute-only
403 			 * reads.
404 			 *
405 			 * Reject request if the file has been opened
406 			 * execute-only and SMB_FLAGS2_READ_IF_EXECUTE is not
407 			 * set.
408 			 */
409 			rc = EACCES;
410 			break;
411 		}
412 
413 		sr->raw_data.max_bytes = vdb->vdb_uio.uio_resid;
414 		top = smb_mbuf_allocate(&vdb->vdb_uio);
415 
416 		rc = smb_fsop_read(sr, sr->user_cr, node, &vdb->vdb_uio);
417 
418 		sr->raw_data.max_bytes -= vdb->vdb_uio.uio_resid;
419 		smb_mbuf_trim(top, sr->raw_data.max_bytes);
420 		MBC_ATTACH_MBUF(&sr->raw_data, top);
421 		break;
422 
423 	case STYPE_IPC:
424 		sr->raw_data.max_bytes = vdb->vdb_uio.uio_resid;
425 		top = smb_mbuf_allocate(&vdb->vdb_uio);
426 
427 		rc = smb_opipe_read(sr, &vdb->vdb_uio);
428 
429 		sr->raw_data.max_bytes -= vdb->vdb_uio.uio_resid;
430 		smb_mbuf_trim(top, sr->raw_data.max_bytes);
431 		MBC_ATTACH_MBUF(&sr->raw_data, top);
432 		break;
433 
434 	default:
435 		rc = EACCES;
436 		break;
437 	}
438 
439 	param->rw_count -= vdb->vdb_uio.uio_resid;
440 
441 	if (rc != 0)
442 		return (rc);
443 
444 	if (param->rw_mincnt != 0 && param->rw_count < param->rw_mincnt) {
445 		/*
446 		 * mincnt is only used by read-raw and is typically
447 		 * zero.  If mincnt is greater than zero and the
448 		 * number of bytes read is less than mincnt, tell
449 		 * the client that we read nothing.
450 		 */
451 		param->rw_count = 0;
452 	}
453 
454 	param->rw_offset += param->rw_count;
455 	mutex_enter(&sr->fid_ofile->f_mutex);
456 	ofile->f_seek_pos = param->rw_offset;
457 	mutex_exit(&sr->fid_ofile->f_mutex);
458 	return (rc);
459 }
460