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                                               uint32_t in_smbpid,
  34                                               uint64_t in_file_id_volatile,
  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         uint32_t in_minimum_count;
  57         uint32_t in_remaining_bytes;
  58         struct tevent_req *subreq;
  59
  60         status = smbd_smb2_request_verify_sizes(req, 0x31);
  61         if (!NT_STATUS_IS_OK(status)) {
  62                 return smbd_smb2_request_error(req, status);
  63         }
  64         inhdr = (const uint8_t *)req->in.vector[i+0].iov_base;
  65         inbody = (const uint8_t *)req->in.vector[i+1].iov_base;
  66
  67         in_smbpid = IVAL(inhdr, SMB2_HDR_PID);
  68
  69         in_length               = IVAL(inbody, 0x04);
  70         in_offset               = BVAL(inbody, 0x08);
  71         in_file_id_persistent   = BVAL(inbody, 0x10);
  72         in_file_id_volatile     = BVAL(inbody, 0x18);
  73         in_minimum_count        = IVAL(inbody, 0x20);
  74         in_remaining_bytes      = IVAL(inbody, 0x28);
  75
  76         /* check the max read size */
  77         if (in_length > req->sconn->smb2.max_read) {
  78                 DEBUG(0,("here:%s: 0x%08X: 0x%08X\n",
  79                         __location__, in_length, req->sconn->smb2.max_read));
  80                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  81         }
  82
  83         if (req->compat_chain_fsp) {
  84                 /* skip check */
  85         } else if (in_file_id_persistent != in_file_id_volatile) {
  86                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  87         }
  88
  89         subreq = smbd_smb2_read_send(req,
  90                                      req->sconn->smb2.event_ctx,
  91                                      req,
  92                                      in_smbpid,
  93                                      in_file_id_volatile,
  94                                      in_length,
  95                                      in_offset,
  96                                      in_minimum_count,
  97                                      in_remaining_bytes);
  98         if (subreq == NULL) {
  99                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 100         }
 101         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
 102
 103         return smbd_smb2_request_pending_queue(req, subreq);
 104 }
 105
 106 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 107 {
 108         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 109                                         struct smbd_smb2_request);
 110         int i = req->current_idx;
 111         uint8_t *outhdr;
 112         DATA_BLOB outbody;
 113         DATA_BLOB outdyn;
 114         uint8_t out_data_offset;
 115         DATA_BLOB out_data_buffer = data_blob_null;
 116         uint32_t out_data_remaining = 0;
 117         NTSTATUS status;
 118         NTSTATUS error; /* transport error */
 119
 120         status = smbd_smb2_read_recv(subreq,
 121                                      req,
 122                                      &out_data_buffer,
 123                                      &out_data_remaining);
 124         TALLOC_FREE(subreq);
 125         if (!NT_STATUS_IS_OK(status)) {
 126                 error = smbd_smb2_request_error(req, status);
 127                 if (!NT_STATUS_IS_OK(error)) {
 128                         smbd_server_connection_terminate(req->sconn,
 129                                                          nt_errstr(error));
 130                         return;
 131                 }
 132                 return;
 133         }
 134
 135         out_data_offset = SMB2_HDR_BODY + 0x10;
 136
 137         outhdr = (uint8_t *)req->out.vector[i].iov_base;
 138
 139         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 140         if (outbody.data == NULL) {
 141                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 142                 if (!NT_STATUS_IS_OK(error)) {
 143                         smbd_server_connection_terminate(req->sconn,
 144                                                          nt_errstr(error));
 145                         return;
 146                 }
 147                 return;
 148         }
 149
 150         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 151         SCVAL(outbody.data, 0x02,
 152               out_data_offset);                 /* data offset */
 153         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 154         SIVAL(outbody.data, 0x04,
 155               out_data_buffer.length);          /* data length */
 156         SIVAL(outbody.data, 0x08,
 157               out_data_remaining);              /* data remaining */
 158         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 159
 160         outdyn = out_data_buffer;
 161
 162         error = smbd_smb2_request_done(req, outbody, &outdyn);
 163         if (!NT_STATUS_IS_OK(error)) {
 164                 smbd_server_connection_terminate(req->sconn,
 165                                                  nt_errstr(error));
 166                 return;
 167         }
 168 }
 169
 170 struct smbd_smb2_read_state {
 171         struct smbd_smb2_request *smb2req;
 172         files_struct *fsp;
 173         uint64_t in_file_id_volatile;
 174         uint32_t in_length;
 175         uint64_t in_offset;
 176         uint32_t in_minimum;
 177         DATA_BLOB out_data;
 178         uint32_t out_remaining;
 179 };
 180
 181 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 182 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 183 {
 184         struct lock_struct lock;
 185         uint32_t in_length = state->in_length;
 186         uint64_t in_offset = state->in_offset;
 187         files_struct *fsp = state->fsp;
 188         ssize_t nread;
 189
 190         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 191                                         fsp,
 192                                         NULL,
 193                                         in_offset,
 194                                         in_length);
 195         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 196                 (int)nread,
 197                 fsp_str_dbg(fsp) ));
 198
 199         if (nread == -1) {
 200                 if (errno == ENOSYS || errno == EINTR) {
 201                         /*
 202                          * Special hack for broken systems with no working
 203                          * sendfile. Fake this up by doing read/write calls.
 204                         */
 205                         set_use_sendfile(SNUM(fsp->conn), false);
 206                         nread = fake_sendfile(fsp, in_offset, in_length);
 207                         if (nread == -1) {
 208                                 DEBUG(0,("smb2_sendfile_send_data: "
 209                                         "fake_sendfile failed for "
 210                                         "file %s (%s).\n",
 211                                         fsp_str_dbg(fsp),
 212                                         strerror(errno)));
 213                                 exit_server_cleanly("smb2_sendfile_send_data: "
 214                                         "fake_sendfile failed");
 215                         }
 216                         goto out;
 217                 }
 218
 219                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 220                         "%s (%s). Terminating\n",
 221                         fsp_str_dbg(fsp),
 222                         strerror(errno)));
 223                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 224         } else if (nread == 0) {
 225                 /*
 226                  * Some sendfile implementations return 0 to indicate
 227                  * that there was a short read, but nothing was
 228                  * actually written to the socket.  In this case,
 229                  * fallback to the normal read path so the header gets
 230                  * the correct byte count.
 231                  */
 232                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 233                         "falling back to the normal read: %s\n",
 234                         fsp_str_dbg(fsp)));
 235
 236                 nread = fake_sendfile(fsp, in_offset, in_length);
 237                 if (nread == -1) {
 238                         DEBUG(0,("smb2_sendfile_send_data: "
 239                                 "fake_sendfile failed for file "
 240                                 "%s (%s). Terminating\n",
 241                                 fsp_str_dbg(fsp),
 242                                 strerror(errno)));
 243                         exit_server_cleanly("smb2_sendfile_send_data: "
 244                                 "fake_sendfile failed");
 245                 }
 246         }
 247
 248   out:
 249
 250         if (nread < in_length) {
 251                 sendfile_short_send(fsp, nread, 0, in_length);
 252         }
 253
 254         init_strict_lock_struct(fsp,
 255                                 state->in_file_id_volatile,
 256                                 in_offset,
 257                                 in_length,
 258                                 READ_LOCK,
 259                                 &lock);
 260
 261         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 262         return 0;
 263 }
 264
 265 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 266                                         struct smbd_smb2_read_state *state)
 267 {
 268         struct smbd_smb2_read_state *state_copy = NULL;
 269         files_struct *fsp = state->fsp;
 270
 271         /*
 272          * We cannot use sendfile if...
 273          * We were not configured to do so OR
 274          * Signing is active OR
 275          * This is a compound SMB2 operation OR
 276          * fsp is a STREAM file OR
 277          * We're using a write cache OR
 278          * It's not a regular file OR
 279          * Requested offset is greater than file size OR
 280          * there's not enough data in the file.
 281          * Phew :-). Luckily this means most
 282          * reads on most normal files. JRA.
 283         */
 284
 285         if (!_lp_use_sendfile(SNUM(fsp->conn)) ||
 286                         smb2req->do_signing ||
 287                         smb2req->in.vector_count != 4 ||
 288                         (fsp->base_fsp != NULL) ||
 289                         (fsp->wcp != NULL) ||
 290                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 291                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 292                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 293                                 state->in_length)) {
 294                 return NT_STATUS_RETRY;
 295         }
 296
 297         /* We've already checked there's this amount of data
 298            to read. */
 299         state->out_data.length = state->in_length;
 300         state->out_remaining = 0;
 301
 302         /* Make a copy of state attached to the smb2req. Attach
 303            the destructor here as this will trigger the sendfile
 304            call when the request is destroyed. */
 305         state_copy = TALLOC_P(smb2req, struct smbd_smb2_read_state);
 306         if (!state_copy) {
 307                 return NT_STATUS_NO_MEMORY;
 308         }
 309         *state_copy = *state;
 310         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 311         return NT_STATUS_OK;
 312 }
 313
 314 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 315
 316 /*******************************************************************
 317  Common read complete processing function for both synchronous and
 318  asynchronous reads.
 319 *******************************************************************/
 320
 321 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 322 {
 323         struct smbd_smb2_read_state *state = tevent_req_data(req,
 324                                         struct smbd_smb2_read_state);
 325         files_struct *fsp = state->fsp;
 326
 327         if (nread < 0) {
 328                 NTSTATUS status = map_nt_error_from_unix(err);
 329
 330                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 331                         "Error = %s (NTSTATUS %s)\n",
 332                         fsp_str_dbg(fsp),
 333                         (int)nread,
 334                         strerror(err),
 335                         nt_errstr(status)));
 336
 337                 return status;
 338         }
 339         if (nread == 0 && state->in_length != 0) {
 340                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 341                         fsp_str_dbg(fsp)));
 342                 return NT_STATUS_END_OF_FILE;
 343         }
 344
 345         if (nread < state->in_minimum) {
 346                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 347                         "minimum requested %u. Returning end of file\n",
 348                         fsp_str_dbg(fsp),
 349                         (int)nread,
 350                         (unsigned int)state->in_minimum));
 351                 return NT_STATUS_END_OF_FILE;
 352         }
 353
 354         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 355                 fsp->fnum,
 356                 fsp_str_dbg(fsp),
 357                 (unsigned long)state->in_length,
 358                 (unsigned long)state->in_offset,
 359                 (unsigned long)nread));
 360
 361         state->out_data.length = nread;
 362         state->out_remaining = 0;
 363
 364         return NT_STATUS_OK;
 365 }
 366
 367 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 368                                               struct tevent_context *ev,
 369                                               struct smbd_smb2_request *smb2req,
 370                                               uint32_t in_smbpid,
 371                                               uint64_t in_file_id_volatile,
 372                                               uint32_t in_length,
 373                                               uint64_t in_offset,
 374                                               uint32_t in_minimum,
 375                                               uint32_t in_remaining)
 376 {
 377         NTSTATUS status;
 378         struct tevent_req *req = NULL;
 379         struct smbd_smb2_read_state *state = NULL;
 380         struct smb_request *smbreq = NULL;
 381         connection_struct *conn = smb2req->tcon->compat_conn;
 382         files_struct *fsp = NULL;
 383         ssize_t nread = -1;
 384         struct lock_struct lock;
 385         int saved_errno;
 386
 387         req = tevent_req_create(mem_ctx, &state,
 388                                 struct smbd_smb2_read_state);
 389         if (req == NULL) {
 390                 return NULL;
 391         }
 392         state->smb2req = smb2req;
 393         state->in_length = in_length;
 394         state->in_offset = in_offset;
 395         state->in_minimum = in_minimum;
 396         state->out_data = data_blob_null;
 397         state->out_remaining = 0;
 398
 399         DEBUG(10,("smbd_smb2_read: file_id[0x%016llX]\n",
 400                   (unsigned long long)in_file_id_volatile));
 401
 402         smbreq = smbd_smb2_fake_smb_request(smb2req);
 403         if (tevent_req_nomem(smbreq, req)) {
 404                 return tevent_req_post(req, ev);
 405         }
 406
 407         fsp = file_fsp(smbreq, (uint16_t)in_file_id_volatile);
 408         if (fsp == NULL) {
 409                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 410                 return tevent_req_post(req, ev);
 411         }
 412         if (conn != fsp->conn) {
 413                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 414                 return tevent_req_post(req, ev);
 415         }
 416         if (smb2req->session->vuid != fsp->vuid) {
 417                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 418                 return tevent_req_post(req, ev);
 419         }
 420         if (fsp->is_directory) {
 421                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 422                 return tevent_req_post(req, ev);
 423         }
 424
 425         state->fsp = fsp;
 426         state->in_file_id_volatile = in_file_id_volatile;
 427
 428         if (IS_IPC(smbreq->conn)) {
 429                 struct tevent_req *subreq = NULL;
 430
 431                 state->out_data = data_blob_talloc(state, NULL, in_length);
 432                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 433                         return tevent_req_post(req, ev);
 434                 }
 435
 436                 if (!fsp_is_np(fsp)) {
 437                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 438                         return tevent_req_post(req, ev);
 439                 }
 440
 441                 subreq = np_read_send(state, smbd_event_context(),
 442                                       fsp->fake_file_handle,
 443                                       state->out_data.data,
 444                                       state->out_data.length);
 445                 if (tevent_req_nomem(subreq, req)) {
 446                         return tevent_req_post(req, ev);
 447                 }
 448                 tevent_req_set_callback(subreq,
 449                                         smbd_smb2_read_pipe_done,
 450                                         req);
 451                 return req;
 452         }
 453
 454         if (!CHECK_READ(fsp, smbreq)) {
 455                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 456                 return tevent_req_post(req, ev);
 457         }
 458
 459         status = schedule_smb2_aio_read(fsp->conn,
 460                                 smbreq,
 461                                 fsp,
 462                                 state,
 463                                 &state->out_data,
 464                                 (SMB_OFF_T)in_offset,
 465                                 (size_t)in_length);
 466
 467         if (NT_STATUS_IS_OK(status)) {
 468                 /*
 469                  * Doing an async read. Don't
 470                  * send a "gone async" message
 471                  * as we expect this to be less
 472                  * than the client timeout period.
 473                  * JRA. FIXME for offline files..
 474                  * FIXME. Add cancel code..
 475                  */
 476                 smb2req->async = true;
 477                 return req;
 478         }
 479
 480         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 481                 /* Real error in setting up aio. Fail. */
 482                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 483                 return tevent_req_post(req, ev);
 484         }
 485
 486         /* Fallback to synchronous. */
 487
 488         init_strict_lock_struct(fsp,
 489                                 in_file_id_volatile,
 490                                 in_offset,
 491                                 in_length,
 492                                 READ_LOCK,
 493                                 &lock);
 494
 495         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 496                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 497                 return tevent_req_post(req, ev);
 498         }
 499
 500         /* Try sendfile in preference. */
 501         status = schedule_smb2_sendfile_read(smb2req, state);
 502         if (NT_STATUS_IS_OK(status)) {
 503                 tevent_req_done(req);
 504                 return tevent_req_post(req, ev);
 505         } else {
 506                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 507                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 508                         tevent_req_nterror(req, status);
 509                         return tevent_req_post(req, ev);
 510                 }
 511         }
 512
 513         /* Ok, read into memory. Allocate the out buffer. */
 514         state->out_data = data_blob_talloc(state, NULL, in_length);
 515         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 516                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 517                 return tevent_req_post(req, ev);
 518         }
 519
 520         nread = read_file(fsp,
 521                           (char *)state->out_data.data,
 522                           in_offset,
 523                           in_length);
 524
 525         saved_errno = errno;
 526
 527         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 528
 529         DEBUG(10,("smbd_smb2_read: file %s handle [0x%016llX] offset=%llu "
 530                 "len=%llu returned %lld\n",
 531                 fsp_str_dbg(fsp),
 532                 (unsigned long long)in_file_id_volatile,
 533                 (unsigned long long)in_offset,
 534                 (unsigned long long)in_length,
 535                 (long long)nread));
 536
 537         status = smb2_read_complete(req, nread, saved_errno);
 538         if (!NT_STATUS_IS_OK(status)) {
 539                 tevent_req_nterror(req, status);
 540         } else {
 541                 /* Success. */
 542                 tevent_req_done(req);
 543         }
 544         return tevent_req_post(req, ev);
 545 }
 546
 547 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 548 {
 549         struct tevent_req *req = tevent_req_callback_data(subreq,
 550                                  struct tevent_req);
 551         struct smbd_smb2_read_state *state = tevent_req_data(req,
 552                                              struct smbd_smb2_read_state);
 553         NTSTATUS status;
 554         ssize_t nread = -1;
 555         bool is_data_outstanding;
 556
 557         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 558         TALLOC_FREE(subreq);
 559         if (!NT_STATUS_IS_OK(status)) {
 560                 tevent_req_nterror(req, status);
 561                 return;
 562         }
 563
 564         if (nread == 0 && state->out_data.length != 0) {
 565                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 566                 return;
 567         }
 568
 569         state->out_data.length = nread;
 570         state->out_remaining = 0;
 571
 572         /*
 573          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 574          * handle it in SMB1 pipe_read_andx_done().
 575          */
 576
 577         tevent_req_done(req);
 578 }
 579
 580 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 581                                     TALLOC_CTX *mem_ctx,
 582                                     DATA_BLOB *out_data,
 583                                     uint32_t *out_remaining)
 584 {
 585         NTSTATUS status;
 586         struct smbd_smb2_read_state *state = tevent_req_data(req,
 587                                              struct smbd_smb2_read_state);
 588
 589         if (tevent_req_is_nterror(req, &status)) {
 590                 tevent_req_received(req);
 591                 return status;
 592         }
 593
 594         *out_data = state->out_data;
 595         talloc_steal(mem_ctx, out_data->data);
 596         *out_remaining = state->out_remaining;
 597
 598         tevent_req_received(req);
 599         return NT_STATUS_OK;
 600 }