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, 500);
 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         struct smb_request *smbreq;
 173         files_struct *fsp;
 174         uint64_t in_file_id_volatile;
 175         uint32_t in_length;
 176         uint64_t in_offset;
 177         uint32_t in_minimum;
 178         DATA_BLOB out_data;
 179         uint32_t out_remaining;
 180 };
 181
 182 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 183 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 184 {
 185         struct lock_struct lock;
 186         uint32_t in_length = state->in_length;
 187         uint64_t in_offset = state->in_offset;
 188         files_struct *fsp = state->fsp;
 189         ssize_t nread;
 190
 191         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 192                                         fsp,
 193                                         NULL,
 194                                         in_offset,
 195                                         in_length);
 196         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 197                 (int)nread,
 198                 fsp_str_dbg(fsp) ));
 199
 200         if (nread == -1) {
 201                 if (errno == ENOSYS || errno == EINTR) {
 202                         /*
 203                          * Special hack for broken systems with no working
 204                          * sendfile. Fake this up by doing read/write calls.
 205                         */
 206                         set_use_sendfile(SNUM(fsp->conn), false);
 207                         nread = fake_sendfile(fsp, in_offset, in_length);
 208                         if (nread == -1) {
 209                                 DEBUG(0,("smb2_sendfile_send_data: "
 210                                         "fake_sendfile failed for "
 211                                         "file %s (%s).\n",
 212                                         fsp_str_dbg(fsp),
 213                                         strerror(errno)));
 214                                 exit_server_cleanly("smb2_sendfile_send_data: "
 215                                         "fake_sendfile failed");
 216                         }
 217                         goto out;
 218                 }
 219
 220                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 221                         "%s (%s). Terminating\n",
 222                         fsp_str_dbg(fsp),
 223                         strerror(errno)));
 224                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 225         } else if (nread == 0) {
 226                 /*
 227                  * Some sendfile implementations return 0 to indicate
 228                  * that there was a short read, but nothing was
 229                  * actually written to the socket.  In this case,
 230                  * fallback to the normal read path so the header gets
 231                  * the correct byte count.
 232                  */
 233                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 234                         "falling back to the normal read: %s\n",
 235                         fsp_str_dbg(fsp)));
 236
 237                 nread = fake_sendfile(fsp, in_offset, in_length);
 238                 if (nread == -1) {
 239                         DEBUG(0,("smb2_sendfile_send_data: "
 240                                 "fake_sendfile failed for file "
 241                                 "%s (%s). Terminating\n",
 242                                 fsp_str_dbg(fsp),
 243                                 strerror(errno)));
 244                         exit_server_cleanly("smb2_sendfile_send_data: "
 245                                 "fake_sendfile failed");
 246                 }
 247         }
 248
 249   out:
 250
 251         if (nread < in_length) {
 252                 sendfile_short_send(fsp, nread, 0, in_length);
 253         }
 254
 255         init_strict_lock_struct(fsp,
 256                                 state->in_file_id_volatile,
 257                                 in_offset,
 258                                 in_length,
 259                                 READ_LOCK,
 260                                 &lock);
 261
 262         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 263         return 0;
 264 }
 265
 266 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 267                                         struct smbd_smb2_read_state *state)
 268 {
 269         struct smbd_smb2_read_state *state_copy = NULL;
 270         files_struct *fsp = state->fsp;
 271
 272         /*
 273          * We cannot use sendfile if...
 274          * We were not configured to do so OR
 275          * Signing is active OR
 276          * This is a compound SMB2 operation OR
 277          * fsp is a STREAM file OR
 278          * We're using a write cache OR
 279          * It's not a regular file OR
 280          * Requested offset is greater than file size OR
 281          * there's not enough data in the file.
 282          * Phew :-). Luckily this means most
 283          * reads on most normal files. JRA.
 284         */
 285
 286         if (!lp__use_sendfile(SNUM(fsp->conn)) ||
 287                         smb2req->do_signing ||
 288                         smb2req->in.vector_count != 4 ||
 289                         (fsp->base_fsp != NULL) ||
 290                         (fsp->wcp != NULL) ||
 291                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 292                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 293                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 294                                 state->in_length)) {
 295                 return NT_STATUS_RETRY;
 296         }
 297
 298         /* We've already checked there's this amount of data
 299            to read. */
 300         state->out_data.length = state->in_length;
 301         state->out_remaining = 0;
 302
 303         /* Make a copy of state attached to the smb2req. Attach
 304            the destructor here as this will trigger the sendfile
 305            call when the request is destroyed. */
 306         state_copy = talloc(smb2req, struct smbd_smb2_read_state);
 307         if (!state_copy) {
 308                 return NT_STATUS_NO_MEMORY;
 309         }
 310         *state_copy = *state;
 311         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 312         return NT_STATUS_OK;
 313 }
 314
 315 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 316
 317 /*******************************************************************
 318  Common read complete processing function for both synchronous and
 319  asynchronous reads.
 320 *******************************************************************/
 321
 322 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 323 {
 324         struct smbd_smb2_read_state *state = tevent_req_data(req,
 325                                         struct smbd_smb2_read_state);
 326         files_struct *fsp = state->fsp;
 327
 328         if (nread < 0) {
 329                 NTSTATUS status = map_nt_error_from_unix(err);
 330
 331                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 332                         "Error = %s (NTSTATUS %s)\n",
 333                         fsp_str_dbg(fsp),
 334                         (int)nread,
 335                         strerror(err),
 336                         nt_errstr(status)));
 337
 338                 return status;
 339         }
 340         if (nread == 0 && state->in_length != 0) {
 341                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 342                         fsp_str_dbg(fsp)));
 343                 return NT_STATUS_END_OF_FILE;
 344         }
 345
 346         if (nread < state->in_minimum) {
 347                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 348                         "minimum requested %u. Returning end of file\n",
 349                         fsp_str_dbg(fsp),
 350                         (int)nread,
 351                         (unsigned int)state->in_minimum));
 352                 return NT_STATUS_END_OF_FILE;
 353         }
 354
 355         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 356                 fsp->fnum,
 357                 fsp_str_dbg(fsp),
 358                 (unsigned long)state->in_length,
 359                 (unsigned long)state->in_offset,
 360                 (unsigned long)nread));
 361
 362         state->out_data.length = nread;
 363         state->out_remaining = 0;
 364
 365         return NT_STATUS_OK;
 366 }
 367
 368 static bool smbd_smb2_read_cancel(struct tevent_req *req)
 369 {
 370         struct smbd_smb2_read_state *state =
 371                 tevent_req_data(req,
 372                 struct smbd_smb2_read_state);
 373
 374         state->smb2req->cancelled = true;
 375
 376         return cancel_smb2_aio(state->smbreq);
 377 }
 378
 379 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 380                                               struct tevent_context *ev,
 381                                               struct smbd_smb2_request *smb2req,
 382                                               uint32_t in_smbpid,
 383                                               uint64_t in_file_id_volatile,
 384                                               uint32_t in_length,
 385                                               uint64_t in_offset,
 386                                               uint32_t in_minimum,
 387                                               uint32_t in_remaining)
 388 {
 389         NTSTATUS status;
 390         struct tevent_req *req = NULL;
 391         struct smbd_smb2_read_state *state = NULL;
 392         struct smb_request *smbreq = NULL;
 393         connection_struct *conn = smb2req->tcon->compat_conn;
 394         files_struct *fsp = NULL;
 395         ssize_t nread = -1;
 396         struct lock_struct lock;
 397         int saved_errno;
 398
 399         req = tevent_req_create(mem_ctx, &state,
 400                                 struct smbd_smb2_read_state);
 401         if (req == NULL) {
 402                 return NULL;
 403         }
 404         state->smb2req = smb2req;
 405         state->in_length = in_length;
 406         state->in_offset = in_offset;
 407         state->in_minimum = in_minimum;
 408         state->out_data = data_blob_null;
 409         state->out_remaining = 0;
 410
 411         DEBUG(10,("smbd_smb2_read: file_id[0x%016llX]\n",
 412                   (unsigned long long)in_file_id_volatile));
 413
 414         smbreq = smbd_smb2_fake_smb_request(smb2req);
 415         if (tevent_req_nomem(smbreq, req)) {
 416                 return tevent_req_post(req, ev);
 417         }
 418         state->smbreq = smbreq;
 419
 420         fsp = file_fsp(smbreq, (uint16_t)in_file_id_volatile);
 421         if (fsp == NULL) {
 422                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 423                 return tevent_req_post(req, ev);
 424         }
 425         if (conn != fsp->conn) {
 426                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 427                 return tevent_req_post(req, ev);
 428         }
 429         if (smb2req->session->vuid != fsp->vuid) {
 430                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 431                 return tevent_req_post(req, ev);
 432         }
 433         if (fsp->is_directory) {
 434                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 435                 return tevent_req_post(req, ev);
 436         }
 437
 438         state->fsp = fsp;
 439         state->in_file_id_volatile = in_file_id_volatile;
 440
 441         if (IS_IPC(smbreq->conn)) {
 442                 struct tevent_req *subreq = NULL;
 443
 444                 state->out_data = data_blob_talloc(state, NULL, in_length);
 445                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 446                         return tevent_req_post(req, ev);
 447                 }
 448
 449                 if (!fsp_is_np(fsp)) {
 450                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 451                         return tevent_req_post(req, ev);
 452                 }
 453
 454                 subreq = np_read_send(state, ev,
 455                                       fsp->fake_file_handle,
 456                                       state->out_data.data,
 457                                       state->out_data.length);
 458                 if (tevent_req_nomem(subreq, req)) {
 459                         return tevent_req_post(req, ev);
 460                 }
 461                 tevent_req_set_callback(subreq,
 462                                         smbd_smb2_read_pipe_done,
 463                                         req);
 464                 return req;
 465         }
 466
 467         if (!CHECK_READ(fsp, smbreq)) {
 468                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 469                 return tevent_req_post(req, ev);
 470         }
 471
 472         status = schedule_smb2_aio_read(fsp->conn,
 473                                 smbreq,
 474                                 fsp,
 475                                 state,
 476                                 &state->out_data,
 477                                 (SMB_OFF_T)in_offset,
 478                                 (size_t)in_length);
 479
 480         if (NT_STATUS_IS_OK(status)) {
 481                 /*
 482                  * Doing an async read, allow this
 483                  * request to be canceled
 484                  */
 485                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
 486                 return req;
 487         }
 488
 489         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 490                 /* Real error in setting up aio. Fail. */
 491                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 492                 return tevent_req_post(req, ev);
 493         }
 494
 495         /* Fallback to synchronous. */
 496
 497         init_strict_lock_struct(fsp,
 498                                 in_file_id_volatile,
 499                                 in_offset,
 500                                 in_length,
 501                                 READ_LOCK,
 502                                 &lock);
 503
 504         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 505                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 506                 return tevent_req_post(req, ev);
 507         }
 508
 509         /* Try sendfile in preference. */
 510         status = schedule_smb2_sendfile_read(smb2req, state);
 511         if (NT_STATUS_IS_OK(status)) {
 512                 tevent_req_done(req);
 513                 return tevent_req_post(req, ev);
 514         } else {
 515                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 516                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 517                         tevent_req_nterror(req, status);
 518                         return tevent_req_post(req, ev);
 519                 }
 520         }
 521
 522         /* Ok, read into memory. Allocate the out buffer. */
 523         state->out_data = data_blob_talloc(state, NULL, in_length);
 524         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 525                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 526                 return tevent_req_post(req, ev);
 527         }
 528
 529         nread = read_file(fsp,
 530                           (char *)state->out_data.data,
 531                           in_offset,
 532                           in_length);
 533
 534         saved_errno = errno;
 535
 536         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 537
 538         DEBUG(10,("smbd_smb2_read: file %s handle [0x%016llX] offset=%llu "
 539                 "len=%llu returned %lld\n",
 540                 fsp_str_dbg(fsp),
 541                 (unsigned long long)in_file_id_volatile,
 542                 (unsigned long long)in_offset,
 543                 (unsigned long long)in_length,
 544                 (long long)nread));
 545
 546         status = smb2_read_complete(req, nread, saved_errno);
 547         if (!NT_STATUS_IS_OK(status)) {
 548                 tevent_req_nterror(req, status);
 549         } else {
 550                 /* Success. */
 551                 tevent_req_done(req);
 552         }
 553         return tevent_req_post(req, ev);
 554 }
 555
 556 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 557 {
 558         struct tevent_req *req = tevent_req_callback_data(subreq,
 559                                  struct tevent_req);
 560         struct smbd_smb2_read_state *state = tevent_req_data(req,
 561                                              struct smbd_smb2_read_state);
 562         NTSTATUS status;
 563         ssize_t nread = -1;
 564         bool is_data_outstanding;
 565
 566         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 567         TALLOC_FREE(subreq);
 568         if (!NT_STATUS_IS_OK(status)) {
 569                 tevent_req_nterror(req, status);
 570                 return;
 571         }
 572
 573         if (nread == 0 && state->out_data.length != 0) {
 574                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 575                 return;
 576         }
 577
 578         state->out_data.length = nread;
 579         state->out_remaining = 0;
 580
 581         /*
 582          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 583          * handle it in SMB1 pipe_read_andx_done().
 584          */
 585
 586         tevent_req_done(req);
 587 }
 588
 589 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 590                                     TALLOC_CTX *mem_ctx,
 591                                     DATA_BLOB *out_data,
 592                                     uint32_t *out_remaining)
 593 {
 594         NTSTATUS status;
 595         struct smbd_smb2_read_state *state = tevent_req_data(req,
 596                                              struct smbd_smb2_read_state);
 597
 598         if (tevent_req_is_nterror(req, &status)) {
 599                 tevent_req_received(req);
 600                 return status;
 601         }
 602
 603         *out_data = state->out_data;
 604         talloc_steal(mem_ctx, out_data->data);
 605         *out_remaining = state->out_remaining;
 606
 607         tevent_req_received(req);
 608         return NT_STATUS_OK;
 609 }