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/globals.h"
  24 #include "../libcli/smb/smb_common.h"
  25 #include "libcli/security/security.h"
  26
  27 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
  28                                               struct tevent_context *ev,
  29                                               struct smbd_smb2_request *smb2req,
  30                                               uint32_t in_smbpid,
  31                                               uint64_t in_file_id_volatile,
  32                                               uint32_t in_length,
  33                                               uint64_t in_offset,
  34                                               uint32_t in_minimum,
  35                                               uint32_t in_remaining);
  36 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
  37                                     TALLOC_CTX *mem_ctx,
  38                                     DATA_BLOB *out_data,
  39                                     uint32_t *out_remaining);
  40
  41 static void smbd_smb2_request_read_done(struct tevent_req *subreq);
  42 NTSTATUS smbd_smb2_request_process_read(struct smbd_smb2_request *req)
  43 {
  44         const uint8_t *inhdr;
  45         const uint8_t *inbody;
  46         int i = req->current_idx;
  47         size_t expected_body_size = 0x31;
  48         size_t body_size;
  49         uint32_t in_smbpid;
  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         uint32_t in_minimum_count;
  55         uint32_t in_remaining_bytes;
  56         struct tevent_req *subreq;
  57
  58         inhdr = (const uint8_t *)req->in.vector[i+0].iov_base;
  59         if (req->in.vector[i+1].iov_len != (expected_body_size & 0xFFFFFFFE)) {
  60                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  61         }
  62
  63         inbody = (const uint8_t *)req->in.vector[i+1].iov_base;
  64
  65         body_size = SVAL(inbody, 0x00);
  66         if (body_size != expected_body_size) {
  67                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  68         }
  69
  70         in_smbpid = IVAL(inhdr, SMB2_HDR_PID);
  71
  72         in_length               = IVAL(inbody, 0x04);
  73         in_offset               = BVAL(inbody, 0x08);
  74         in_file_id_persistent   = BVAL(inbody, 0x10);
  75         in_file_id_volatile     = BVAL(inbody, 0x18);
  76         in_minimum_count        = IVAL(inbody, 0x20);
  77         in_remaining_bytes      = IVAL(inbody, 0x28);
  78
  79         /* check the max read size */
  80         if (in_length > lp_smb2_max_read()) {
  81                 DEBUG(0,("here:%s: 0x%08X: 0x%08X\n",
  82                         __location__, in_length, lp_smb2_max_read()));
  83                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  84         }
  85
  86         if (req->compat_chain_fsp) {
  87                 /* skip check */
  88         } else if (in_file_id_persistent != in_file_id_volatile) {
  89                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  90         }
  91
  92         subreq = smbd_smb2_read_send(req,
  93                                      req->sconn->smb2.event_ctx,
  94                                      req,
  95                                      in_smbpid,
  96                                      in_file_id_volatile,
  97                                      in_length,
  98                                      in_offset,
  99                                      in_minimum_count,
 100                                      in_remaining_bytes);
 101         if (subreq == NULL) {
 102                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 103         }
 104         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
 105
 106         return smbd_smb2_request_pending_queue(req, subreq);
 107 }
 108
 109 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 110 {
 111         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 112                                         struct smbd_smb2_request);
 113         int i = req->current_idx;
 114         uint8_t *outhdr;
 115         DATA_BLOB outbody;
 116         DATA_BLOB outdyn;
 117         uint8_t out_data_offset;
 118         DATA_BLOB out_data_buffer = data_blob_null;
 119         uint32_t out_data_remaining = 0;
 120         NTSTATUS status;
 121         NTSTATUS error; /* transport error */
 122
 123         status = smbd_smb2_read_recv(subreq,
 124                                      req,
 125                                      &out_data_buffer,
 126                                      &out_data_remaining);
 127         TALLOC_FREE(subreq);
 128         if (!NT_STATUS_IS_OK(status)) {
 129                 error = smbd_smb2_request_error(req, status);
 130                 if (!NT_STATUS_IS_OK(error)) {
 131                         smbd_server_connection_terminate(req->sconn,
 132                                                          nt_errstr(error));
 133                         return;
 134                 }
 135                 return;
 136         }
 137
 138         out_data_offset = SMB2_HDR_BODY + 0x10;
 139
 140         outhdr = (uint8_t *)req->out.vector[i].iov_base;
 141
 142         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 143         if (outbody.data == NULL) {
 144                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 145                 if (!NT_STATUS_IS_OK(error)) {
 146                         smbd_server_connection_terminate(req->sconn,
 147                                                          nt_errstr(error));
 148                         return;
 149                 }
 150                 return;
 151         }
 152
 153         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 154         SCVAL(outbody.data, 0x02,
 155               out_data_offset);                 /* data offset */
 156         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 157         SIVAL(outbody.data, 0x04,
 158               out_data_buffer.length);          /* data length */
 159         SIVAL(outbody.data, 0x08,
 160               out_data_remaining);              /* data remaining */
 161         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 162
 163         outdyn = out_data_buffer;
 164
 165         error = smbd_smb2_request_done(req, outbody, &outdyn);
 166         if (!NT_STATUS_IS_OK(error)) {
 167                 smbd_server_connection_terminate(req->sconn,
 168                                                  nt_errstr(error));
 169                 return;
 170         }
 171 }
 172
 173 struct smbd_smb2_read_state {
 174         struct smbd_smb2_request *smb2req;
 175         files_struct *fsp;
 176         uint64_t in_file_id_volatile;
 177         uint32_t in_length;
 178         uint64_t in_offset;
 179         uint32_t in_minimum;
 180         DATA_BLOB out_data;
 181         uint32_t out_remaining;
 182 };
 183
 184 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 185 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 186 {
 187         struct lock_struct lock;
 188         uint32_t in_length = state->in_length;
 189         uint64_t in_offset = state->in_offset;
 190         files_struct *fsp = state->fsp;
 191         ssize_t nread;
 192
 193         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 194                                         fsp,
 195                                         NULL,
 196                                         in_offset,
 197                                         in_length);
 198         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 199                 (int)nread,
 200                 fsp_str_dbg(fsp) ));
 201
 202         if (nread == -1) {
 203                 if (errno == ENOSYS || errno == EINTR) {
 204                         /*
 205                          * Special hack for broken systems with no working
 206                          * sendfile. Fake this up by doing read/write calls.
 207                         */
 208                         set_use_sendfile(SNUM(fsp->conn), false);
 209                         nread = fake_sendfile(fsp, in_offset, in_length);
 210                         if (nread == -1) {
 211                                 DEBUG(0,("smb2_sendfile_send_data: "
 212                                         "fake_sendfile failed for "
 213                                         "file %s (%s).\n",
 214                                         fsp_str_dbg(fsp),
 215                                         strerror(errno)));
 216                                 exit_server_cleanly("smb2_sendfile_send_data: "
 217                                         "fake_sendfile failed");
 218                         }
 219                         goto out;
 220                 }
 221
 222                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 223                         "%s (%s). Terminating\n",
 224                         fsp_str_dbg(fsp),
 225                         strerror(errno)));
 226                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 227         } else if (nread == 0) {
 228                 /*
 229                  * Some sendfile implementations return 0 to indicate
 230                  * that there was a short read, but nothing was
 231                  * actually written to the socket.  In this case,
 232                  * fallback to the normal read path so the header gets
 233                  * the correct byte count.
 234                  */
 235                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 236                         "falling back to the normal read: %s\n",
 237                         fsp_str_dbg(fsp)));
 238
 239                 nread = fake_sendfile(fsp, in_offset, in_length);
 240                 if (nread == -1) {
 241                         DEBUG(0,("smb2_sendfile_send_data: "
 242                                 "fake_sendfile failed for file "
 243                                 "%s (%s). Terminating\n",
 244                                 fsp_str_dbg(fsp),
 245                                 strerror(errno)));
 246                         exit_server_cleanly("smb2_sendfile_send_data: "
 247                                 "fake_sendfile failed");
 248                 }
 249         }
 250
 251   out:
 252
 253         if (nread < in_length) {
 254                 sendfile_short_send(fsp, nread, 0, in_length);
 255         }
 256
 257         init_strict_lock_struct(fsp,
 258                                 state->in_file_id_volatile,
 259                                 in_offset,
 260                                 in_length,
 261                                 READ_LOCK,
 262                                 &lock);
 263
 264         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 265         return 0;
 266 }
 267
 268 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 269                                         struct smbd_smb2_read_state *state)
 270 {
 271         struct smbd_smb2_read_state *state_copy = NULL;
 272         files_struct *fsp = state->fsp;
 273
 274         /*
 275          * We cannot use sendfile if...
 276          * We were not configured to do so OR
 277          * Signing is active OR
 278          * This is a compound SMB2 operation OR
 279          * fsp is a STREAM file OR
 280          * We're using a write cache OR
 281          * It's not a regular file OR
 282          * Requested offset is greater than file size OR
 283          * there's not enough data in the file.
 284          * Phew :-). Luckily this means most
 285          * reads on most normal files. JRA.
 286         */
 287
 288         if (!_lp_use_sendfile(SNUM(fsp->conn)) ||
 289                         smb2req->do_signing ||
 290                         smb2req->in.vector_count != 4 ||
 291                         (fsp->base_fsp != NULL) ||
 292                         (fsp->wcp != NULL) ||
 293                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 294                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 295                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 296                                 state->in_length)) {
 297                 return NT_STATUS_RETRY;
 298         }
 299
 300         /* We've already checked there's this amount of data
 301            to read. */
 302         state->out_data.length = state->in_length;
 303         state->out_remaining = 0;
 304
 305         /* Make a copy of state attached to the smb2req. Attach
 306            the destructor here as this will trigger the sendfile
 307            call when the request is destroyed. */
 308         state_copy = TALLOC_P(smb2req, struct smbd_smb2_read_state);
 309         if (!state_copy) {
 310                 return NT_STATUS_NO_MEMORY;
 311         }
 312         *state_copy = *state;
 313         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 314         return NT_STATUS_OK;
 315 }
 316
 317 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 318
 319 /*******************************************************************
 320  Common read complete processing function for both synchronous and
 321  asynchronous reads.
 322 *******************************************************************/
 323
 324 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 325 {
 326         struct smbd_smb2_read_state *state = tevent_req_data(req,
 327                                         struct smbd_smb2_read_state);
 328         files_struct *fsp = state->fsp;
 329
 330         if (nread < 0) {
 331                 NTSTATUS status = map_nt_error_from_unix(err);
 332
 333                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 334                         "Error = %s (NTSTATUS %s)\n",
 335                         fsp_str_dbg(fsp),
 336                         (int)nread,
 337                         strerror(err),
 338                         nt_errstr(status)));
 339
 340                 return status;
 341         }
 342         if (nread == 0 && state->in_length != 0) {
 343                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 344                         fsp_str_dbg(fsp)));
 345                 return NT_STATUS_END_OF_FILE;
 346         }
 347
 348         if (nread < state->in_minimum) {
 349                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 350                         "minimum requested %u. Returning end of file\n",
 351                         fsp_str_dbg(fsp),
 352                         (int)nread,
 353                         (unsigned int)state->in_minimum));
 354                 return NT_STATUS_END_OF_FILE;
 355         }
 356
 357         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 358                 fsp->fnum,
 359                 fsp_str_dbg(fsp),
 360                 (unsigned long)state->in_length,
 361                 (unsigned long)state->in_offset,
 362                 (unsigned long)nread));
 363
 364         state->out_data.length = nread;
 365         state->out_remaining = 0;
 366
 367         return NT_STATUS_OK;
 368 }
 369
 370 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 371                                               struct tevent_context *ev,
 372                                               struct smbd_smb2_request *smb2req,
 373                                               uint32_t in_smbpid,
 374                                               uint64_t in_file_id_volatile,
 375                                               uint32_t in_length,
 376                                               uint64_t in_offset,
 377                                               uint32_t in_minimum,
 378                                               uint32_t in_remaining)
 379 {
 380         NTSTATUS status;
 381         struct tevent_req *req = NULL;
 382         struct smbd_smb2_read_state *state = NULL;
 383         struct smb_request *smbreq = NULL;
 384         connection_struct *conn = smb2req->tcon->compat_conn;
 385         files_struct *fsp = NULL;
 386         ssize_t nread = -1;
 387         struct lock_struct lock;
 388         int saved_errno;
 389
 390         req = tevent_req_create(mem_ctx, &state,
 391                                 struct smbd_smb2_read_state);
 392         if (req == NULL) {
 393                 return NULL;
 394         }
 395         state->smb2req = smb2req;
 396         state->in_length = in_length;
 397         state->in_offset = in_offset;
 398         state->in_minimum = in_minimum;
 399         state->out_data = data_blob_null;
 400         state->out_remaining = 0;
 401
 402         DEBUG(10,("smbd_smb2_read: file_id[0x%016llX]\n",
 403                   (unsigned long long)in_file_id_volatile));
 404
 405         smbreq = smbd_smb2_fake_smb_request(smb2req);
 406         if (tevent_req_nomem(smbreq, req)) {
 407                 return tevent_req_post(req, ev);
 408         }
 409
 410         fsp = file_fsp(smbreq, (uint16_t)in_file_id_volatile);
 411         if (fsp == NULL) {
 412                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 413                 return tevent_req_post(req, ev);
 414         }
 415         if (conn != fsp->conn) {
 416                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 417                 return tevent_req_post(req, ev);
 418         }
 419         if (smb2req->session->vuid != fsp->vuid) {
 420                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 421                 return tevent_req_post(req, ev);
 422         }
 423         if (fsp->is_directory) {
 424                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 425                 return tevent_req_post(req, ev);
 426         }
 427
 428         state->fsp = fsp;
 429         state->in_file_id_volatile = in_file_id_volatile;
 430
 431         if (IS_IPC(smbreq->conn)) {
 432                 struct tevent_req *subreq = NULL;
 433
 434                 state->out_data = data_blob_talloc(state, NULL, in_length);
 435                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 436                         return tevent_req_post(req, ev);
 437                 }
 438
 439                 if (!fsp_is_np(fsp)) {
 440                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 441                         return tevent_req_post(req, ev);
 442                 }
 443
 444                 subreq = np_read_send(state, smbd_event_context(),
 445                                       fsp->fake_file_handle,
 446                                       state->out_data.data,
 447                                       state->out_data.length);
 448                 if (tevent_req_nomem(subreq, req)) {
 449                         return tevent_req_post(req, ev);
 450                 }
 451                 tevent_req_set_callback(subreq,
 452                                         smbd_smb2_read_pipe_done,
 453                                         req);
 454                 return req;
 455         }
 456
 457         if (!CHECK_READ(fsp, smbreq)) {
 458                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 459                 return tevent_req_post(req, ev);
 460         }
 461
 462         status = schedule_smb2_aio_read(fsp->conn,
 463                                 smbreq,
 464                                 fsp,
 465                                 state,
 466                                 &state->out_data,
 467                                 (SMB_OFF_T)in_offset,
 468                                 (size_t)in_length);
 469
 470         if (NT_STATUS_IS_OK(status)) {
 471                 /*
 472                  * Doing an async read. Don't
 473                  * send a "gone async" message
 474                  * as we expect this to be less
 475                  * than the client timeout period.
 476                  * JRA. FIXME for offline files..
 477                  * FIXME. Add cancel code..
 478                  */
 479                 smb2req->async = true;
 480                 return req;
 481         }
 482
 483         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 484                 /* Real error in setting up aio. Fail. */
 485                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 486                 return tevent_req_post(req, ev);
 487         }
 488
 489         /* Fallback to synchronous. */
 490
 491         init_strict_lock_struct(fsp,
 492                                 in_file_id_volatile,
 493                                 in_offset,
 494                                 in_length,
 495                                 READ_LOCK,
 496                                 &lock);
 497
 498         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 499                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 500                 return tevent_req_post(req, ev);
 501         }
 502
 503         /* Try sendfile in preference. */
 504         status = schedule_smb2_sendfile_read(smb2req, state);
 505         if (NT_STATUS_IS_OK(status)) {
 506                 tevent_req_done(req);
 507                 return tevent_req_post(req, ev);
 508         } else {
 509                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 510                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 511                         tevent_req_nterror(req, status);
 512                         return tevent_req_post(req, ev);
 513                 }
 514         }
 515
 516         /* Ok, read into memory. Allocate the out buffer. */
 517         state->out_data = data_blob_talloc(state, NULL, in_length);
 518         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 519                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 520                 return tevent_req_post(req, ev);
 521         }
 522
 523         nread = read_file(fsp,
 524                           (char *)state->out_data.data,
 525                           in_offset,
 526                           in_length);
 527
 528         saved_errno = errno;
 529
 530         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 531
 532         DEBUG(10,("smbd_smb2_read: file %s handle [0x%016llX] offset=%llu "
 533                 "len=%llu returned %lld\n",
 534                 fsp_str_dbg(fsp),
 535                 (unsigned long long)in_file_id_volatile,
 536                 (unsigned long long)in_offset,
 537                 (unsigned long long)in_length,
 538                 (long long)nread));
 539
 540         status = smb2_read_complete(req, nread, saved_errno);
 541         if (!NT_STATUS_IS_OK(status)) {
 542                 tevent_req_nterror(req, status);
 543         } else {
 544                 /* Success. */
 545                 tevent_req_done(req);
 546         }
 547         return tevent_req_post(req, ev);
 548 }
 549
 550 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 551 {
 552         struct tevent_req *req = tevent_req_callback_data(subreq,
 553                                  struct tevent_req);
 554         struct smbd_smb2_read_state *state = tevent_req_data(req,
 555                                              struct smbd_smb2_read_state);
 556         NTSTATUS status;
 557         ssize_t nread = -1;
 558         bool is_data_outstanding;
 559
 560         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 561         TALLOC_FREE(subreq);
 562         if (!NT_STATUS_IS_OK(status)) {
 563                 tevent_req_nterror(req, status);
 564                 return;
 565         }
 566
 567         if (nread == 0 && state->out_data.length != 0) {
 568                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 569                 return;
 570         }
 571
 572         state->out_data.length = nread;
 573         state->out_remaining = 0;
 574
 575         tevent_req_done(req);
 576 }
 577
 578 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 579                                     TALLOC_CTX *mem_ctx,
 580                                     DATA_BLOB *out_data,
 581                                     uint32_t *out_remaining)
 582 {
 583         NTSTATUS status;
 584         struct smbd_smb2_read_state *state = tevent_req_data(req,
 585                                              struct smbd_smb2_read_state);
 586
 587         if (tevent_req_is_nterror(req, &status)) {
 588                 tevent_req_received(req);
 589                 return status;
 590         }
 591
 592         *out_data = state->out_data;
 593         talloc_steal(mem_ctx, out_data->data);
 594         *out_remaining = state->out_remaining;
 595
 596         tevent_req_received(req);
 597         return NT_STATUS_OK;
 598 }