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
  30 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
  31                                               struct tevent_context *ev,
  32                                               struct smbd_smb2_request *smb2req,
  33                                               struct files_struct *in_fsp,
  34                                               uint32_t in_smbpid,
  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         NTSTATUS status;
  48         const uint8_t *inhdr;
  49         const uint8_t *inbody;
  50         int i = req->current_idx;
  51         uint32_t in_smbpid;
  52         uint32_t in_length;
  53         uint64_t in_offset;
  54         uint64_t in_file_id_persistent;
  55         uint64_t in_file_id_volatile;
  56         struct files_struct *in_fsp;
  57         uint32_t in_minimum_count;
  58         uint32_t in_remaining_bytes;
  59         struct tevent_req *subreq;
  60
  61         status = smbd_smb2_request_verify_sizes(req, 0x31);
  62         if (!NT_STATUS_IS_OK(status)) {
  63                 return smbd_smb2_request_error(req, status);
  64         }
  65         inhdr = (const uint8_t *)req->in.vector[i+0].iov_base;
  66         inbody = (const uint8_t *)req->in.vector[i+1].iov_base;
  67
  68         in_smbpid = IVAL(inhdr, SMB2_HDR_PID);
  69
  70         in_length               = IVAL(inbody, 0x04);
  71         in_offset               = BVAL(inbody, 0x08);
  72         in_file_id_persistent   = BVAL(inbody, 0x10);
  73         in_file_id_volatile     = BVAL(inbody, 0x18);
  74         in_minimum_count        = IVAL(inbody, 0x20);
  75         in_remaining_bytes      = IVAL(inbody, 0x28);
  76
  77         /* check the max read size */
  78         if (in_length > req->sconn->smb2.max_read) {
  79                 DEBUG(0,("here:%s: 0x%08X: 0x%08X\n",
  80                         __location__, in_length, req->sconn->smb2.max_read));
  81                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  82         }
  83
  84         in_fsp = file_fsp_smb2(req, in_file_id_persistent, in_file_id_volatile);
  85         if (in_fsp == NULL) {
  86                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  87         }
  88
  89         subreq = smbd_smb2_read_send(req, req->sconn->smb2.event_ctx,
  90                                      req, in_fsp,
  91                                      in_smbpid,
  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);
 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         int i = req->current_idx;
 109         uint8_t *outhdr;
 110         DATA_BLOB outbody;
 111         DATA_BLOB outdyn;
 112         uint8_t out_data_offset;
 113         DATA_BLOB out_data_buffer = data_blob_null;
 114         uint32_t out_data_remaining = 0;
 115         NTSTATUS status;
 116         NTSTATUS error; /* transport error */
 117
 118         status = smbd_smb2_read_recv(subreq,
 119                                      req,
 120                                      &out_data_buffer,
 121                                      &out_data_remaining);
 122         TALLOC_FREE(subreq);
 123         if (!NT_STATUS_IS_OK(status)) {
 124                 error = smbd_smb2_request_error(req, status);
 125                 if (!NT_STATUS_IS_OK(error)) {
 126                         smbd_server_connection_terminate(req->sconn,
 127                                                          nt_errstr(error));
 128                         return;
 129                 }
 130                 return;
 131         }
 132
 133         out_data_offset = SMB2_HDR_BODY + 0x10;
 134
 135         outhdr = (uint8_t *)req->out.vector[i].iov_base;
 136
 137         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 138         if (outbody.data == NULL) {
 139                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 140                 if (!NT_STATUS_IS_OK(error)) {
 141                         smbd_server_connection_terminate(req->sconn,
 142                                                          nt_errstr(error));
 143                         return;
 144                 }
 145                 return;
 146         }
 147
 148         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 149         SCVAL(outbody.data, 0x02,
 150               out_data_offset);                 /* data offset */
 151         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 152         SIVAL(outbody.data, 0x04,
 153               out_data_buffer.length);          /* data length */
 154         SIVAL(outbody.data, 0x08,
 155               out_data_remaining);              /* data remaining */
 156         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 157
 158         outdyn = out_data_buffer;
 159
 160         error = smbd_smb2_request_done(req, outbody, &outdyn);
 161         if (!NT_STATUS_IS_OK(error)) {
 162                 smbd_server_connection_terminate(req->sconn,
 163                                                  nt_errstr(error));
 164                 return;
 165         }
 166 }
 167
 168 struct smbd_smb2_read_state {
 169         struct smbd_smb2_request *smb2req;
 170         files_struct *fsp;
 171         uint32_t in_length;
 172         uint64_t in_offset;
 173         uint32_t in_minimum;
 174         DATA_BLOB out_data;
 175         uint32_t out_remaining;
 176 };
 177
 178 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 179 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 180 {
 181         struct lock_struct lock;
 182         uint32_t in_length = state->in_length;
 183         uint64_t in_offset = state->in_offset;
 184         files_struct *fsp = state->fsp;
 185         ssize_t nread;
 186
 187         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 188                                         fsp,
 189                                         NULL,
 190                                         in_offset,
 191                                         in_length);
 192         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 193                 (int)nread,
 194                 fsp_str_dbg(fsp) ));
 195
 196         if (nread == -1) {
 197                 if (errno == ENOSYS || errno == EINTR) {
 198                         /*
 199                          * Special hack for broken systems with no working
 200                          * sendfile. Fake this up by doing read/write calls.
 201                         */
 202                         set_use_sendfile(SNUM(fsp->conn), false);
 203                         nread = fake_sendfile(fsp, in_offset, in_length);
 204                         if (nread == -1) {
 205                                 DEBUG(0,("smb2_sendfile_send_data: "
 206                                         "fake_sendfile failed for "
 207                                         "file %s (%s).\n",
 208                                         fsp_str_dbg(fsp),
 209                                         strerror(errno)));
 210                                 exit_server_cleanly("smb2_sendfile_send_data: "
 211                                         "fake_sendfile failed");
 212                         }
 213                         goto out;
 214                 }
 215
 216                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 217                         "%s (%s). Terminating\n",
 218                         fsp_str_dbg(fsp),
 219                         strerror(errno)));
 220                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 221         } else if (nread == 0) {
 222                 /*
 223                  * Some sendfile implementations return 0 to indicate
 224                  * that there was a short read, but nothing was
 225                  * actually written to the socket.  In this case,
 226                  * fallback to the normal read path so the header gets
 227                  * the correct byte count.
 228                  */
 229                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 230                         "falling back to the normal read: %s\n",
 231                         fsp_str_dbg(fsp)));
 232
 233                 nread = fake_sendfile(fsp, in_offset, in_length);
 234                 if (nread == -1) {
 235                         DEBUG(0,("smb2_sendfile_send_data: "
 236                                 "fake_sendfile failed for file "
 237                                 "%s (%s). Terminating\n",
 238                                 fsp_str_dbg(fsp),
 239                                 strerror(errno)));
 240                         exit_server_cleanly("smb2_sendfile_send_data: "
 241                                 "fake_sendfile failed");
 242                 }
 243         }
 244
 245   out:
 246
 247         if (nread < in_length) {
 248                 sendfile_short_send(fsp, nread, 0, in_length);
 249         }
 250
 251         init_strict_lock_struct(fsp,
 252                                 fsp->fnum,
 253                                 in_offset,
 254                                 in_length,
 255                                 READ_LOCK,
 256                                 &lock);
 257
 258         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 259         return 0;
 260 }
 261
 262 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 263                                         struct smbd_smb2_read_state *state)
 264 {
 265         struct smbd_smb2_read_state *state_copy = NULL;
 266         files_struct *fsp = state->fsp;
 267
 268         /*
 269          * We cannot use sendfile if...
 270          * We were not configured to do so OR
 271          * Signing is active OR
 272          * This is a compound SMB2 operation OR
 273          * fsp is a STREAM file OR
 274          * We're using a write cache OR
 275          * It's not a regular file OR
 276          * Requested offset is greater than file size OR
 277          * there's not enough data in the file.
 278          * Phew :-). Luckily this means most
 279          * reads on most normal files. JRA.
 280         */
 281
 282         if (!_lp_use_sendfile(SNUM(fsp->conn)) ||
 283                         smb2req->do_signing ||
 284                         smb2req->in.vector_count != 4 ||
 285                         (fsp->base_fsp != NULL) ||
 286                         (fsp->wcp != NULL) ||
 287                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 288                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 289                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 290                                 state->in_length)) {
 291                 return NT_STATUS_RETRY;
 292         }
 293
 294         /* We've already checked there's this amount of data
 295            to read. */
 296         state->out_data.length = state->in_length;
 297         state->out_remaining = 0;
 298
 299         /* Make a copy of state attached to the smb2req. Attach
 300            the destructor here as this will trigger the sendfile
 301            call when the request is destroyed. */
 302         state_copy = TALLOC_P(smb2req, struct smbd_smb2_read_state);
 303         if (!state_copy) {
 304                 return NT_STATUS_NO_MEMORY;
 305         }
 306         *state_copy = *state;
 307         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 308         return NT_STATUS_OK;
 309 }
 310
 311 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 312
 313 /*******************************************************************
 314  Common read complete processing function for both synchronous and
 315  asynchronous reads.
 316 *******************************************************************/
 317
 318 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 319 {
 320         struct smbd_smb2_read_state *state = tevent_req_data(req,
 321                                         struct smbd_smb2_read_state);
 322         files_struct *fsp = state->fsp;
 323
 324         if (nread < 0) {
 325                 NTSTATUS status = map_nt_error_from_unix(err);
 326
 327                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 328                         "Error = %s (NTSTATUS %s)\n",
 329                         fsp_str_dbg(fsp),
 330                         (int)nread,
 331                         strerror(err),
 332                         nt_errstr(status)));
 333
 334                 return status;
 335         }
 336         if (nread == 0 && state->in_length != 0) {
 337                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 338                         fsp_str_dbg(fsp)));
 339                 return NT_STATUS_END_OF_FILE;
 340         }
 341
 342         if (nread < state->in_minimum) {
 343                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 344                         "minimum requested %u. Returning end of file\n",
 345                         fsp_str_dbg(fsp),
 346                         (int)nread,
 347                         (unsigned int)state->in_minimum));
 348                 return NT_STATUS_END_OF_FILE;
 349         }
 350
 351         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 352                 fsp->fnum,
 353                 fsp_str_dbg(fsp),
 354                 (unsigned long)state->in_length,
 355                 (unsigned long)state->in_offset,
 356                 (unsigned long)nread));
 357
 358         state->out_data.length = nread;
 359         state->out_remaining = 0;
 360
 361         return NT_STATUS_OK;
 362 }
 363
 364 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 365                                               struct tevent_context *ev,
 366                                               struct smbd_smb2_request *smb2req,
 367                                               struct files_struct *fsp,
 368                                               uint32_t in_smbpid,
 369                                               uint32_t in_length,
 370                                               uint64_t in_offset,
 371                                               uint32_t in_minimum,
 372                                               uint32_t in_remaining)
 373 {
 374         NTSTATUS status;
 375         struct tevent_req *req = NULL;
 376         struct smbd_smb2_read_state *state = NULL;
 377         struct smb_request *smbreq = NULL;
 378         connection_struct *conn = smb2req->tcon->compat_conn;
 379         ssize_t nread = -1;
 380         struct lock_struct lock;
 381         int saved_errno;
 382
 383         req = tevent_req_create(mem_ctx, &state,
 384                                 struct smbd_smb2_read_state);
 385         if (req == NULL) {
 386                 return NULL;
 387         }
 388         state->smb2req = smb2req;
 389         state->in_length = in_length;
 390         state->in_offset = in_offset;
 391         state->in_minimum = in_minimum;
 392         state->out_data = data_blob_null;
 393         state->out_remaining = 0;
 394
 395         DEBUG(10,("smbd_smb2_read: %s - fnum[%d]\n",
 396                   fsp_str_dbg(fsp), fsp->fnum));
 397
 398         smbreq = smbd_smb2_fake_smb_request(smb2req);
 399         if (tevent_req_nomem(smbreq, req)) {
 400                 return tevent_req_post(req, ev);
 401         }
 402
 403         if (fsp->is_directory) {
 404                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 405                 return tevent_req_post(req, ev);
 406         }
 407
 408         state->fsp = fsp;
 409
 410         if (IS_IPC(smbreq->conn)) {
 411                 struct tevent_req *subreq = NULL;
 412
 413                 state->out_data = data_blob_talloc(state, NULL, in_length);
 414                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 415                         return tevent_req_post(req, ev);
 416                 }
 417
 418                 if (!fsp_is_np(fsp)) {
 419                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 420                         return tevent_req_post(req, ev);
 421                 }
 422
 423                 subreq = np_read_send(state, smbd_event_context(),
 424                                       fsp->fake_file_handle,
 425                                       state->out_data.data,
 426                                       state->out_data.length);
 427                 if (tevent_req_nomem(subreq, req)) {
 428                         return tevent_req_post(req, ev);
 429                 }
 430                 tevent_req_set_callback(subreq,
 431                                         smbd_smb2_read_pipe_done,
 432                                         req);
 433                 return req;
 434         }
 435
 436         if (!CHECK_READ(fsp, smbreq)) {
 437                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 438                 return tevent_req_post(req, ev);
 439         }
 440
 441         status = schedule_smb2_aio_read(fsp->conn,
 442                                 smbreq,
 443                                 fsp,
 444                                 state,
 445                                 &state->out_data,
 446                                 (SMB_OFF_T)in_offset,
 447                                 (size_t)in_length);
 448
 449         if (NT_STATUS_IS_OK(status)) {
 450                 /*
 451                  * Doing an async read. Don't
 452                  * send a "gone async" message
 453                  * as we expect this to be less
 454                  * than the client timeout period.
 455                  * JRA. FIXME for offline files..
 456                  * FIXME. Add cancel code..
 457                  */
 458                 smb2req->async = true;
 459                 return req;
 460         }
 461
 462         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 463                 /* Real error in setting up aio. Fail. */
 464                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 465                 return tevent_req_post(req, ev);
 466         }
 467
 468         /* Fallback to synchronous. */
 469
 470         init_strict_lock_struct(fsp,
 471                                 fsp->fnum,
 472                                 in_offset,
 473                                 in_length,
 474                                 READ_LOCK,
 475                                 &lock);
 476
 477         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 478                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 479                 return tevent_req_post(req, ev);
 480         }
 481
 482         /* Try sendfile in preference. */
 483         status = schedule_smb2_sendfile_read(smb2req, state);
 484         if (NT_STATUS_IS_OK(status)) {
 485                 tevent_req_done(req);
 486                 return tevent_req_post(req, ev);
 487         } else {
 488                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 489                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 490                         tevent_req_nterror(req, status);
 491                         return tevent_req_post(req, ev);
 492                 }
 493         }
 494
 495         /* Ok, read into memory. Allocate the out buffer. */
 496         state->out_data = data_blob_talloc(state, NULL, in_length);
 497         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 498                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 499                 return tevent_req_post(req, ev);
 500         }
 501
 502         nread = read_file(fsp,
 503                           (char *)state->out_data.data,
 504                           in_offset,
 505                           in_length);
 506
 507         saved_errno = errno;
 508
 509         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 510
 511         DEBUG(10,("smbd_smb2_read: file %s fnum[%d] offset=%llu "
 512                 "len=%llu returned %lld\n",
 513                 fsp_str_dbg(fsp),
 514                 fsp->fnum,
 515                 (unsigned long long)in_offset,
 516                 (unsigned long long)in_length,
 517                 (long long)nread));
 518
 519         status = smb2_read_complete(req, nread, saved_errno);
 520         if (!NT_STATUS_IS_OK(status)) {
 521                 tevent_req_nterror(req, status);
 522         } else {
 523                 /* Success. */
 524                 tevent_req_done(req);
 525         }
 526         return tevent_req_post(req, ev);
 527 }
 528
 529 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 530 {
 531         struct tevent_req *req = tevent_req_callback_data(subreq,
 532                                  struct tevent_req);
 533         struct smbd_smb2_read_state *state = tevent_req_data(req,
 534                                              struct smbd_smb2_read_state);
 535         NTSTATUS status;
 536         ssize_t nread = -1;
 537         bool is_data_outstanding;
 538
 539         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 540         TALLOC_FREE(subreq);
 541         if (!NT_STATUS_IS_OK(status)) {
 542                 tevent_req_nterror(req, status);
 543                 return;
 544         }
 545
 546         if (nread == 0 && state->out_data.length != 0) {
 547                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 548                 return;
 549         }
 550
 551         state->out_data.length = nread;
 552         state->out_remaining = 0;
 553
 554         /*
 555          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 556          * handle it in SMB1 pipe_read_andx_done().
 557          */
 558
 559         tevent_req_done(req);
 560 }
 561
 562 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 563                                     TALLOC_CTX *mem_ctx,
 564                                     DATA_BLOB *out_data,
 565                                     uint32_t *out_remaining)
 566 {
 567         NTSTATUS status;
 568         struct smbd_smb2_read_state *state = tevent_req_data(req,
 569                                              struct smbd_smb2_read_state);
 570
 571         if (tevent_req_is_nterror(req, &status)) {
 572                 tevent_req_received(req);
 573                 return status;
 574         }
 575
 576         *out_data = state->out_data;
 577         talloc_steal(mem_ctx, out_data->data);
 578         *out_remaining = state->out_remaining;
 579
 580         tevent_req_received(req);
 581         return NT_STATUS_OK;
 582 }