lib/texpect: prefer bsd/libutil.h if available
[obnox/samba/samba-obnox.git] / source3 / smbd / smb2_read.c
1 /*
2    Unix SMB/CIFS implementation.
3    Core SMB2 server
4
5    Copyright (C) Stefan Metzmacher 2009
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 #include "system/filesys.h"
23 #include "smbd/smbd.h"
24 #include "smbd/globals.h"
25 #include "../libcli/smb/smb_common.h"
26 #include "libcli/security/security.h"
27 #include "../lib/util/tevent_ntstatus.h"
28 #include "rpc_server/srv_pipe_hnd.h"
29 #include "lib/sys_rw_data.h"
30
31 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
32                                               struct tevent_context *ev,
33                                               struct smbd_smb2_request *smb2req,
34                                               struct files_struct *in_fsp,
35                                               uint32_t in_length,
36                                               uint64_t in_offset,
37                                               uint32_t in_minimum,
38                                               uint32_t in_remaining);
39 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
40                                     TALLOC_CTX *mem_ctx,
41                                     DATA_BLOB *out_data,
42                                     uint32_t *out_remaining);
43
44 static void smbd_smb2_request_read_done(struct tevent_req *subreq);
45 NTSTATUS smbd_smb2_request_process_read(struct smbd_smb2_request *req)
46 {
47         struct smbXsrv_connection *xconn = req->xconn;
48         NTSTATUS status;
49         const uint8_t *inbody;
50         uint32_t in_length;
51         uint64_t in_offset;
52         uint64_t in_file_id_persistent;
53         uint64_t in_file_id_volatile;
54         struct files_struct *in_fsp;
55         uint32_t in_minimum_count;
56         uint32_t in_remaining_bytes;
57         struct tevent_req *subreq;
58
59         status = smbd_smb2_request_verify_sizes(req, 0x31);
60         if (!NT_STATUS_IS_OK(status)) {
61                 return smbd_smb2_request_error(req, status);
62         }
63         inbody = SMBD_SMB2_IN_BODY_PTR(req);
64
65         in_length               = IVAL(inbody, 0x04);
66         in_offset               = BVAL(inbody, 0x08);
67         in_file_id_persistent   = BVAL(inbody, 0x10);
68         in_file_id_volatile     = BVAL(inbody, 0x18);
69         in_minimum_count        = IVAL(inbody, 0x20);
70         in_remaining_bytes      = IVAL(inbody, 0x28);
71
72         /* check the max read size */
73         if (in_length > xconn->smb2.server.max_read) {
74                 DEBUG(2,("smbd_smb2_request_process_read: "
75                          "client ignored max read: %s: 0x%08X: 0x%08X\n",
76                         __location__, in_length, xconn->smb2.server.max_read));
77                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
78         }
79
80         status = smbd_smb2_request_verify_creditcharge(req, in_length);
81         if (!NT_STATUS_IS_OK(status)) {
82                 return smbd_smb2_request_error(req, status);
83         }
84
85         in_fsp = file_fsp_smb2(req, in_file_id_persistent, in_file_id_volatile);
86         if (in_fsp == NULL) {
87                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
88         }
89
90         subreq = smbd_smb2_read_send(req, req->sconn->ev_ctx,
91                                      req, in_fsp,
92                                      in_length,
93                                      in_offset,
94                                      in_minimum_count,
95                                      in_remaining_bytes);
96         if (subreq == NULL) {
97                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
98         }
99         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
100
101         return smbd_smb2_request_pending_queue(req, subreq, 500);
102 }
103
104 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
105 {
106         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
107                                         struct smbd_smb2_request);
108         DATA_BLOB outbody;
109         DATA_BLOB outdyn;
110         uint8_t out_data_offset;
111         DATA_BLOB out_data_buffer = data_blob_null;
112         uint32_t out_data_remaining = 0;
113         NTSTATUS status;
114         NTSTATUS error; /* transport error */
115
116         status = smbd_smb2_read_recv(subreq,
117                                      req,
118                                      &out_data_buffer,
119                                      &out_data_remaining);
120         TALLOC_FREE(subreq);
121         if (!NT_STATUS_IS_OK(status)) {
122                 error = smbd_smb2_request_error(req, status);
123                 if (!NT_STATUS_IS_OK(error)) {
124                         smbd_server_connection_terminate(req->xconn,
125                                                          nt_errstr(error));
126                         return;
127                 }
128                 return;
129         }
130
131         out_data_offset = SMB2_HDR_BODY + 0x10;
132
133         outbody = smbd_smb2_generate_outbody(req, 0x10);
134         if (outbody.data == NULL) {
135                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
136                 if (!NT_STATUS_IS_OK(error)) {
137                         smbd_server_connection_terminate(req->xconn,
138                                                          nt_errstr(error));
139                         return;
140                 }
141                 return;
142         }
143
144         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
145         SCVAL(outbody.data, 0x02,
146               out_data_offset);                 /* data offset */
147         SCVAL(outbody.data, 0x03, 0);           /* reserved */
148         SIVAL(outbody.data, 0x04,
149               out_data_buffer.length);          /* data length */
150         SIVAL(outbody.data, 0x08,
151               out_data_remaining);              /* data remaining */
152         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
153
154         outdyn = out_data_buffer;
155
156         error = smbd_smb2_request_done(req, outbody, &outdyn);
157         if (!NT_STATUS_IS_OK(error)) {
158                 smbd_server_connection_terminate(req->xconn,
159                                                  nt_errstr(error));
160                 return;
161         }
162 }
163
164 struct smbd_smb2_read_state {
165         struct smbd_smb2_request *smb2req;
166         struct smb_request *smbreq;
167         files_struct *fsp;
168         uint32_t in_length;
169         uint64_t in_offset;
170         uint32_t in_minimum;
171         DATA_BLOB out_headers;
172         uint8_t _out_hdr_buf[NBT_HDR_SIZE + SMB2_HDR_BODY + 0x10];
173         DATA_BLOB out_data;
174         uint32_t out_remaining;
175 };
176
177 static int smb2_smb2_read_state_deny_destructor(struct smbd_smb2_read_state *state)
178 {
179         return -1;
180 }
181
182 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
183 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
184 {
185         struct lock_struct lock;
186         uint32_t in_length = state->in_length;
187         uint64_t in_offset = state->in_offset;
188         files_struct *fsp = state->fsp;
189         const DATA_BLOB *hdr = state->smb2req->queue_entry.sendfile_header;
190         NTSTATUS *pstatus = state->smb2req->queue_entry.sendfile_status;
191         struct smbXsrv_connection *xconn = state->smb2req->xconn;
192         ssize_t nread;
193         ssize_t ret;
194         int saved_errno;
195
196         nread = SMB_VFS_SENDFILE(xconn->transport.sock,
197                                  fsp,
198                                  hdr,
199                                  in_offset,
200                                  in_length);
201         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
202                 (int)nread,
203                 fsp_str_dbg(fsp) ));
204
205         if (nread == -1) {
206                 saved_errno = errno;
207
208                 /*
209                  * Returning ENOSYS means no data at all was sent.
210                    Do this as a normal read. */
211                 if (errno == ENOSYS) {
212                         goto normal_read;
213                 }
214
215                 if (errno == EINTR) {
216                         /*
217                          * Special hack for broken Linux with no working sendfile. If we
218                          * return EINTR we sent the header but not the rest of the data.
219                          * Fake this up by doing read/write calls.
220                          */
221                         set_use_sendfile(SNUM(fsp->conn), false);
222                         nread = fake_sendfile(xconn, fsp, in_offset, in_length);
223                         if (nread == -1) {
224                                 saved_errno = errno;
225                                 DEBUG(0,("smb2_sendfile_send_data: fake_sendfile "
226                                          "failed for file %s (%s) for client %s. "
227                                          "Terminating\n",
228                                          fsp_str_dbg(fsp), strerror(saved_errno),
229                                          smbXsrv_connection_dbg(xconn)));
230                                 *pstatus = map_nt_error_from_unix_common(saved_errno);
231                                 return 0;
232                         }
233                         goto out;
234                 }
235
236                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
237                          "%s (%s) for client %s. Terminating\n",
238                          fsp_str_dbg(fsp), strerror(saved_errno),
239                          smbXsrv_connection_dbg(xconn)));
240                 *pstatus = map_nt_error_from_unix_common(saved_errno);
241                 return 0;
242         } else if (nread == 0) {
243                 /*
244                  * Some sendfile implementations return 0 to indicate
245                  * that there was a short read, but nothing was
246                  * actually written to the socket.  In this case,
247                  * fallback to the normal read path so the header gets
248                  * the correct byte count.
249                  */
250                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
251                         "falling back to the normal read: %s\n",
252                         fsp_str_dbg(fsp)));
253                 goto normal_read;
254         }
255
256         /*
257          * We got a short read
258          */
259         goto out;
260
261 normal_read:
262         /* Send out the header. */
263         ret = write_data(xconn->transport.sock,
264                          (const char *)hdr->data, hdr->length);
265         if (ret != hdr->length) {
266                 saved_errno = errno;
267                 DEBUG(0,("smb2_sendfile_send_data: write_data failed for file "
268                          "%s (%s) for client %s. Terminating\n",
269                          fsp_str_dbg(fsp), strerror(saved_errno),
270                          smbXsrv_connection_dbg(xconn)));
271                 *pstatus = map_nt_error_from_unix_common(saved_errno);
272                 return 0;
273         }
274         nread = fake_sendfile(xconn, fsp, in_offset, in_length);
275         if (nread == -1) {
276                 saved_errno = errno;
277                 DEBUG(0,("smb2_sendfile_send_data: fake_sendfile "
278                          "failed for file %s (%s) for client %s. "
279                          "Terminating\n",
280                          fsp_str_dbg(fsp), strerror(saved_errno),
281                          smbXsrv_connection_dbg(xconn)));
282                 *pstatus = map_nt_error_from_unix_common(saved_errno);
283                 return 0;
284         }
285
286   out:
287
288         if (nread < in_length) {
289                 ret = sendfile_short_send(xconn, fsp, nread,
290                                           hdr->length, in_length);
291                 if (ret == -1) {
292                         saved_errno = errno;
293                         DEBUG(0,("%s: sendfile_short_send "
294                                  "failed for file %s (%s) for client %s. "
295                                  "Terminating\n",
296                                  __func__,
297                                  fsp_str_dbg(fsp), strerror(saved_errno),
298                                  smbXsrv_connection_dbg(xconn)));
299                         *pstatus = map_nt_error_from_unix_common(saved_errno);
300                         return 0;
301                 }
302         }
303
304         init_strict_lock_struct(fsp,
305                                 fsp->op->global->open_persistent_id,
306                                 in_offset,
307                                 in_length,
308                                 READ_LOCK,
309                                 &lock);
310
311         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
312
313         *pstatus = NT_STATUS_OK;
314         return 0;
315 }
316
317 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
318                                         struct smbd_smb2_read_state *state)
319 {
320         files_struct *fsp = state->fsp;
321
322         /*
323          * We cannot use sendfile if...
324          * We were not configured to do so OR
325          * Signing is active OR
326          * This is a compound SMB2 operation OR
327          * fsp is a STREAM file OR
328          * We're using a write cache OR
329          * It's not a regular file OR
330          * Requested offset is greater than file size OR
331          * there's not enough data in the file.
332          * Phew :-). Luckily this means most
333          * reads on most normal files. JRA.
334         */
335
336         if (!lp__use_sendfile(SNUM(fsp->conn)) ||
337             smb2req->do_signing ||
338             smb2req->do_encryption ||
339             smb2req->in.vector_count >= (2*SMBD_SMB2_NUM_IOV_PER_REQ) ||
340             (fsp->base_fsp != NULL) ||
341             (fsp->wcp != NULL) ||
342             (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
343             (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
344             (fsp->fsp_name->st.st_ex_size < state->in_offset + state->in_length))
345         {
346                 return NT_STATUS_RETRY;
347         }
348
349         /* We've already checked there's this amount of data
350            to read. */
351         state->out_data.length = state->in_length;
352         state->out_remaining = 0;
353
354         state->out_headers = data_blob_const(state->_out_hdr_buf,
355                                              sizeof(state->_out_hdr_buf));
356         return NT_STATUS_OK;
357 }
358
359 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
360
361 /*******************************************************************
362  Common read complete processing function for both synchronous and
363  asynchronous reads.
364 *******************************************************************/
365
366 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
367 {
368         struct smbd_smb2_read_state *state = tevent_req_data(req,
369                                         struct smbd_smb2_read_state);
370         files_struct *fsp = state->fsp;
371
372         if (nread < 0) {
373                 NTSTATUS status = map_nt_error_from_unix(err);
374
375                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
376                         "Error = %s (NTSTATUS %s)\n",
377                         fsp_str_dbg(fsp),
378                         (int)nread,
379                         strerror(err),
380                         nt_errstr(status)));
381
382                 return status;
383         }
384         if (nread == 0 && state->in_length != 0) {
385                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
386                         fsp_str_dbg(fsp)));
387                 return NT_STATUS_END_OF_FILE;
388         }
389
390         if (nread < state->in_minimum) {
391                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
392                         "minimum requested %u. Returning end of file\n",
393                         fsp_str_dbg(fsp),
394                         (int)nread,
395                         (unsigned int)state->in_minimum));
396                 return NT_STATUS_END_OF_FILE;
397         }
398
399         DEBUG(3,("smbd_smb2_read: %s, file %s, length=%lu offset=%lu read=%lu\n",
400                 fsp_fnum_dbg(fsp),
401                 fsp_str_dbg(fsp),
402                 (unsigned long)state->in_length,
403                 (unsigned long)state->in_offset,
404                 (unsigned long)nread));
405
406         state->out_data.length = nread;
407         state->out_remaining = 0;
408
409         return NT_STATUS_OK;
410 }
411
412 static bool smbd_smb2_read_cancel(struct tevent_req *req)
413 {
414         struct smbd_smb2_read_state *state =
415                 tevent_req_data(req,
416                 struct smbd_smb2_read_state);
417
418         return cancel_smb2_aio(state->smbreq);
419 }
420
421 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
422                                               struct tevent_context *ev,
423                                               struct smbd_smb2_request *smb2req,
424                                               struct files_struct *fsp,
425                                               uint32_t in_length,
426                                               uint64_t in_offset,
427                                               uint32_t in_minimum,
428                                               uint32_t in_remaining)
429 {
430         NTSTATUS status;
431         struct tevent_req *req = NULL;
432         struct smbd_smb2_read_state *state = NULL;
433         struct smb_request *smbreq = NULL;
434         connection_struct *conn = smb2req->tcon->compat;
435         ssize_t nread = -1;
436         struct lock_struct lock;
437         int saved_errno;
438
439         req = tevent_req_create(mem_ctx, &state,
440                                 struct smbd_smb2_read_state);
441         if (req == NULL) {
442                 return NULL;
443         }
444         state->smb2req = smb2req;
445         state->in_length = in_length;
446         state->in_offset = in_offset;
447         state->in_minimum = in_minimum;
448         state->out_data = data_blob_null;
449         state->out_remaining = 0;
450
451         DEBUG(10,("smbd_smb2_read: %s - %s\n",
452                   fsp_str_dbg(fsp), fsp_fnum_dbg(fsp)));
453
454         smbreq = smbd_smb2_fake_smb_request(smb2req);
455         if (tevent_req_nomem(smbreq, req)) {
456                 return tevent_req_post(req, ev);
457         }
458         state->smbreq = smbreq;
459
460         if (fsp->is_directory) {
461                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
462                 return tevent_req_post(req, ev);
463         }
464
465         state->fsp = fsp;
466
467         if (IS_IPC(smbreq->conn)) {
468                 struct tevent_req *subreq = NULL;
469
470                 state->out_data = data_blob_talloc(state, NULL, in_length);
471                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
472                         return tevent_req_post(req, ev);
473                 }
474
475                 if (!fsp_is_np(fsp)) {
476                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
477                         return tevent_req_post(req, ev);
478                 }
479
480                 subreq = np_read_send(state, ev,
481                                       fsp->fake_file_handle,
482                                       state->out_data.data,
483                                       state->out_data.length);
484                 if (tevent_req_nomem(subreq, req)) {
485                         return tevent_req_post(req, ev);
486                 }
487                 tevent_req_set_callback(subreq,
488                                         smbd_smb2_read_pipe_done,
489                                         req);
490                 return req;
491         }
492
493         if (!CHECK_READ(fsp, smbreq)) {
494                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
495                 return tevent_req_post(req, ev);
496         }
497
498         status = schedule_smb2_aio_read(fsp->conn,
499                                 smbreq,
500                                 fsp,
501                                 state,
502                                 &state->out_data,
503                                 (off_t)in_offset,
504                                 (size_t)in_length);
505
506         if (NT_STATUS_IS_OK(status)) {
507                 /*
508                  * Doing an async read, allow this
509                  * request to be canceled
510                  */
511                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
512                 return req;
513         }
514
515         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
516                 /* Real error in setting up aio. Fail. */
517                 tevent_req_nterror(req, status);
518                 return tevent_req_post(req, ev);
519         }
520
521         /* Fallback to synchronous. */
522
523         init_strict_lock_struct(fsp,
524                                 fsp->op->global->open_persistent_id,
525                                 in_offset,
526                                 in_length,
527                                 READ_LOCK,
528                                 &lock);
529
530         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
531                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
532                 return tevent_req_post(req, ev);
533         }
534
535         /* Try sendfile in preference. */
536         status = schedule_smb2_sendfile_read(smb2req, state);
537         if (NT_STATUS_IS_OK(status)) {
538                 tevent_req_done(req);
539                 return tevent_req_post(req, ev);
540         } else {
541                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
542                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
543                         tevent_req_nterror(req, status);
544                         return tevent_req_post(req, ev);
545                 }
546         }
547
548         /* Ok, read into memory. Allocate the out buffer. */
549         state->out_data = data_blob_talloc(state, NULL, in_length);
550         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
551                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
552                 return tevent_req_post(req, ev);
553         }
554
555         nread = read_file(fsp,
556                           (char *)state->out_data.data,
557                           in_offset,
558                           in_length);
559
560         saved_errno = errno;
561
562         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
563
564         DEBUG(10,("smbd_smb2_read: file %s, %s, offset=%llu "
565                 "len=%llu returned %lld\n",
566                 fsp_str_dbg(fsp),
567                 fsp_fnum_dbg(fsp),
568                 (unsigned long long)in_offset,
569                 (unsigned long long)in_length,
570                 (long long)nread));
571
572         status = smb2_read_complete(req, nread, saved_errno);
573         if (!NT_STATUS_IS_OK(status)) {
574                 tevent_req_nterror(req, status);
575         } else {
576                 /* Success. */
577                 tevent_req_done(req);
578         }
579         return tevent_req_post(req, ev);
580 }
581
582 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
583 {
584         struct tevent_req *req = tevent_req_callback_data(subreq,
585                                  struct tevent_req);
586         struct smbd_smb2_read_state *state = tevent_req_data(req,
587                                              struct smbd_smb2_read_state);
588         NTSTATUS status;
589         ssize_t nread = -1;
590         bool is_data_outstanding;
591
592         status = np_read_recv(subreq, &nread, &is_data_outstanding);
593         TALLOC_FREE(subreq);
594         if (!NT_STATUS_IS_OK(status)) {
595                 NTSTATUS old = status;
596                 status = nt_status_np_pipe(old);
597                 tevent_req_nterror(req, status);
598                 return;
599         }
600
601         if (nread == 0 && state->out_data.length != 0) {
602                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
603                 return;
604         }
605
606         state->out_data.length = nread;
607         state->out_remaining = 0;
608
609         /*
610          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
611          * handle it in SMB1 pipe_read_andx_done().
612          */
613
614         tevent_req_done(req);
615 }
616
617 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
618                                     TALLOC_CTX *mem_ctx,
619                                     DATA_BLOB *out_data,
620                                     uint32_t *out_remaining)
621 {
622         NTSTATUS status;
623         struct smbd_smb2_read_state *state = tevent_req_data(req,
624                                              struct smbd_smb2_read_state);
625
626         if (tevent_req_is_nterror(req, &status)) {
627                 tevent_req_received(req);
628                 return status;
629         }
630
631         *out_data = state->out_data;
632         talloc_steal(mem_ctx, out_data->data);
633         *out_remaining = state->out_remaining;
634
635         if (state->out_headers.length > 0) {
636                 talloc_steal(mem_ctx, state);
637                 talloc_set_destructor(state, smb2_smb2_read_state_deny_destructor);
638                 tevent_req_received(req);
639                 state->smb2req->queue_entry.sendfile_header = &state->out_headers;
640                 talloc_set_destructor(state, smb2_sendfile_send_data);
641         } else {
642                 tevent_req_received(req);
643         }
644
645         return NT_STATUS_OK;
646 }