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