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         const uint8_t *inhdr;
  48         const uint8_t *inbody;
  49         int i = req->current_idx;
  50         size_t expected_body_size = 0x31;
  51         size_t body_size;
  52         uint32_t in_smbpid;
  53         uint32_t in_length;
  54         uint64_t in_offset;
  55         uint64_t in_file_id_persistent;
  56         uint64_t in_file_id_volatile;
  57         uint32_t in_minimum_count;
  58         uint32_t in_remaining_bytes;
  59         struct tevent_req *subreq;
  60
  61         inhdr = (const uint8_t *)req->in.vector[i+0].iov_base;
  62         if (req->in.vector[i+1].iov_len != (expected_body_size & 0xFFFFFFFE)) {
  63                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  64         }
  65
  66         inbody = (const uint8_t *)req->in.vector[i+1].iov_base;
  67
  68         body_size = SVAL(inbody, 0x00);
  69         if (body_size != expected_body_size) {
  70                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  71         }
  72
  73         in_smbpid = IVAL(inhdr, SMB2_HDR_PID);
  74
  75         in_length               = IVAL(inbody, 0x04);
  76         in_offset               = BVAL(inbody, 0x08);
  77         in_file_id_persistent   = BVAL(inbody, 0x10);
  78         in_file_id_volatile     = BVAL(inbody, 0x18);
  79         in_minimum_count        = IVAL(inbody, 0x20);
  80         in_remaining_bytes      = IVAL(inbody, 0x28);
  81
  82         /* check the max read size */
  83         if (in_length > lp_smb2_max_read()) {
  84                 DEBUG(0,("here:%s: 0x%08X: 0x%08X\n",
  85                         __location__, in_length, lp_smb2_max_read()));
  86                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  87         }
  88
  89         if (req->compat_chain_fsp) {
  90                 /* skip check */
  91         } else if (in_file_id_persistent != in_file_id_volatile) {
  92                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  93         }
  94
  95         subreq = smbd_smb2_read_send(req,
  96                                      req->sconn->smb2.event_ctx,
  97                                      req,
  98                                      in_smbpid,
  99                                      in_file_id_volatile,
 100                                      in_length,
 101                                      in_offset,
 102                                      in_minimum_count,
 103                                      in_remaining_bytes);
 104         if (subreq == NULL) {
 105                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 106         }
 107         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
 108
 109         return smbd_smb2_request_pending_queue(req, subreq);
 110 }
 111
 112 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 113 {
 114         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 115                                         struct smbd_smb2_request);
 116         int i = req->current_idx;
 117         uint8_t *outhdr;
 118         DATA_BLOB outbody;
 119         DATA_BLOB outdyn;
 120         uint8_t out_data_offset;
 121         DATA_BLOB out_data_buffer = data_blob_null;
 122         uint32_t out_data_remaining = 0;
 123         NTSTATUS status;
 124         NTSTATUS error; /* transport error */
 125
 126         status = smbd_smb2_read_recv(subreq,
 127                                      req,
 128                                      &out_data_buffer,
 129                                      &out_data_remaining);
 130         TALLOC_FREE(subreq);
 131         if (!NT_STATUS_IS_OK(status)) {
 132                 error = smbd_smb2_request_error(req, status);
 133                 if (!NT_STATUS_IS_OK(error)) {
 134                         smbd_server_connection_terminate(req->sconn,
 135                                                          nt_errstr(error));
 136                         return;
 137                 }
 138                 return;
 139         }
 140
 141         out_data_offset = SMB2_HDR_BODY + 0x10;
 142
 143         outhdr = (uint8_t *)req->out.vector[i].iov_base;
 144
 145         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 146         if (outbody.data == NULL) {
 147                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 148                 if (!NT_STATUS_IS_OK(error)) {
 149                         smbd_server_connection_terminate(req->sconn,
 150                                                          nt_errstr(error));
 151                         return;
 152                 }
 153                 return;
 154         }
 155
 156         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 157         SCVAL(outbody.data, 0x02,
 158               out_data_offset);                 /* data offset */
 159         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 160         SIVAL(outbody.data, 0x04,
 161               out_data_buffer.length);          /* data length */
 162         SIVAL(outbody.data, 0x08,
 163               out_data_remaining);              /* data remaining */
 164         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 165
 166         outdyn = out_data_buffer;
 167
 168         error = smbd_smb2_request_done(req, outbody, &outdyn);
 169         if (!NT_STATUS_IS_OK(error)) {
 170                 smbd_server_connection_terminate(req->sconn,
 171                                                  nt_errstr(error));
 172                 return;
 173         }
 174 }
 175
 176 struct smbd_smb2_read_state {
 177         struct smbd_smb2_request *smb2req;
 178         files_struct *fsp;
 179         uint64_t in_file_id_volatile;
 180         uint32_t in_length;
 181         uint64_t in_offset;
 182         uint32_t in_minimum;
 183         DATA_BLOB out_data;
 184         uint32_t out_remaining;
 185 };
 186
 187 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 188 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 189 {
 190         struct lock_struct lock;
 191         uint32_t in_length = state->in_length;
 192         uint64_t in_offset = state->in_offset;
 193         files_struct *fsp = state->fsp;
 194         ssize_t nread;
 195
 196         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 197                                         fsp,
 198                                         NULL,
 199                                         in_offset,
 200                                         in_length);
 201         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 202                 (int)nread,
 203                 fsp_str_dbg(fsp) ));
 204
 205         if (nread == -1) {
 206                 if (errno == ENOSYS || errno == EINTR) {
 207                         /*
 208                          * Special hack for broken systems with no working
 209                          * sendfile. Fake this up by doing read/write calls.
 210                         */
 211                         set_use_sendfile(SNUM(fsp->conn), false);
 212                         nread = fake_sendfile(fsp, in_offset, in_length);
 213                         if (nread == -1) {
 214                                 DEBUG(0,("smb2_sendfile_send_data: "
 215                                         "fake_sendfile failed for "
 216                                         "file %s (%s).\n",
 217                                         fsp_str_dbg(fsp),
 218                                         strerror(errno)));
 219                                 exit_server_cleanly("smb2_sendfile_send_data: "
 220                                         "fake_sendfile failed");
 221                         }
 222                         goto out;
 223                 }
 224
 225                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 226                         "%s (%s). Terminating\n",
 227                         fsp_str_dbg(fsp),
 228                         strerror(errno)));
 229                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 230         } else if (nread == 0) {
 231                 /*
 232                  * Some sendfile implementations return 0 to indicate
 233                  * that there was a short read, but nothing was
 234                  * actually written to the socket.  In this case,
 235                  * fallback to the normal read path so the header gets
 236                  * the correct byte count.
 237                  */
 238                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 239                         "falling back to the normal read: %s\n",
 240                         fsp_str_dbg(fsp)));
 241
 242                 nread = fake_sendfile(fsp, in_offset, in_length);
 243                 if (nread == -1) {
 244                         DEBUG(0,("smb2_sendfile_send_data: "
 245                                 "fake_sendfile failed for file "
 246                                 "%s (%s). Terminating\n",
 247                                 fsp_str_dbg(fsp),
 248                                 strerror(errno)));
 249                         exit_server_cleanly("smb2_sendfile_send_data: "
 250                                 "fake_sendfile failed");
 251                 }
 252         }
 253
 254   out:
 255
 256         if (nread < in_length) {
 257                 sendfile_short_send(fsp, nread, 0, in_length);
 258         }
 259
 260         init_strict_lock_struct(fsp,
 261                                 state->in_file_id_volatile,
 262                                 in_offset,
 263                                 in_length,
 264                                 READ_LOCK,
 265                                 &lock);
 266
 267         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 268         return 0;
 269 }
 270
 271 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 272                                         struct smbd_smb2_read_state *state)
 273 {
 274         struct smbd_smb2_read_state *state_copy = NULL;
 275         files_struct *fsp = state->fsp;
 276
 277         /*
 278          * We cannot use sendfile if...
 279          * We were not configured to do so OR
 280          * Signing is active OR
 281          * This is a compound SMB2 operation OR
 282          * fsp is a STREAM file OR
 283          * We're using a write cache OR
 284          * It's not a regular file OR
 285          * Requested offset is greater than file size OR
 286          * there's not enough data in the file.
 287          * Phew :-). Luckily this means most
 288          * reads on most normal files. JRA.
 289         */
 290
 291         if (!_lp_use_sendfile(SNUM(fsp->conn)) ||
 292                         smb2req->do_signing ||
 293                         smb2req->in.vector_count != 4 ||
 294                         (fsp->base_fsp != NULL) ||
 295                         (fsp->wcp != NULL) ||
 296                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 297                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 298                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 299                                 state->in_length)) {
 300                 return NT_STATUS_RETRY;
 301         }
 302
 303         /* We've already checked there's this amount of data
 304            to read. */
 305         state->out_data.length = state->in_length;
 306         state->out_remaining = 0;
 307
 308         /* Make a copy of state attached to the smb2req. Attach
 309            the destructor here as this will trigger the sendfile
 310            call when the request is destroyed. */
 311         state_copy = TALLOC_P(smb2req, struct smbd_smb2_read_state);
 312         if (!state_copy) {
 313                 return NT_STATUS_NO_MEMORY;
 314         }
 315         *state_copy = *state;
 316         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 317         return NT_STATUS_OK;
 318 }
 319
 320 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 321
 322 /*******************************************************************
 323  Common read complete processing function for both synchronous and
 324  asynchronous reads.
 325 *******************************************************************/
 326
 327 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 328 {
 329         struct smbd_smb2_read_state *state = tevent_req_data(req,
 330                                         struct smbd_smb2_read_state);
 331         files_struct *fsp = state->fsp;
 332
 333         if (nread < 0) {
 334                 NTSTATUS status = map_nt_error_from_unix(err);
 335
 336                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 337                         "Error = %s (NTSTATUS %s)\n",
 338                         fsp_str_dbg(fsp),
 339                         (int)nread,
 340                         strerror(err),
 341                         nt_errstr(status)));
 342
 343                 return status;
 344         }
 345         if (nread == 0 && state->in_length != 0) {
 346                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 347                         fsp_str_dbg(fsp)));
 348                 return NT_STATUS_END_OF_FILE;
 349         }
 350
 351         if (nread < state->in_minimum) {
 352                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 353                         "minimum requested %u. Returning end of file\n",
 354                         fsp_str_dbg(fsp),
 355                         (int)nread,
 356                         (unsigned int)state->in_minimum));
 357                 return NT_STATUS_END_OF_FILE;
 358         }
 359
 360         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 361                 fsp->fnum,
 362                 fsp_str_dbg(fsp),
 363                 (unsigned long)state->in_length,
 364                 (unsigned long)state->in_offset,
 365                 (unsigned long)nread));
 366
 367         state->out_data.length = nread;
 368         state->out_remaining = 0;
 369
 370         return NT_STATUS_OK;
 371 }
 372
 373 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 374                                               struct tevent_context *ev,
 375                                               struct smbd_smb2_request *smb2req,
 376                                               uint32_t in_smbpid,
 377                                               uint64_t in_file_id_volatile,
 378                                               uint32_t in_length,
 379                                               uint64_t in_offset,
 380                                               uint32_t in_minimum,
 381                                               uint32_t in_remaining)
 382 {
 383         NTSTATUS status;
 384         struct tevent_req *req = NULL;
 385         struct smbd_smb2_read_state *state = NULL;
 386         struct smb_request *smbreq = NULL;
 387         connection_struct *conn = smb2req->tcon->compat_conn;
 388         files_struct *fsp = NULL;
 389         ssize_t nread = -1;
 390         struct lock_struct lock;
 391         int saved_errno;
 392
 393         req = tevent_req_create(mem_ctx, &state,
 394                                 struct smbd_smb2_read_state);
 395         if (req == NULL) {
 396                 return NULL;
 397         }
 398         state->smb2req = smb2req;
 399         state->in_length = in_length;
 400         state->in_offset = in_offset;
 401         state->in_minimum = in_minimum;
 402         state->out_data = data_blob_null;
 403         state->out_remaining = 0;
 404
 405         DEBUG(10,("smbd_smb2_read: file_id[0x%016llX]\n",
 406                   (unsigned long long)in_file_id_volatile));
 407
 408         smbreq = smbd_smb2_fake_smb_request(smb2req);
 409         if (tevent_req_nomem(smbreq, req)) {
 410                 return tevent_req_post(req, ev);
 411         }
 412
 413         fsp = file_fsp(smbreq, (uint16_t)in_file_id_volatile);
 414         if (fsp == NULL) {
 415                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 416                 return tevent_req_post(req, ev);
 417         }
 418         if (conn != fsp->conn) {
 419                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 420                 return tevent_req_post(req, ev);
 421         }
 422         if (smb2req->session->vuid != fsp->vuid) {
 423                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 424                 return tevent_req_post(req, ev);
 425         }
 426         if (fsp->is_directory) {
 427                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 428                 return tevent_req_post(req, ev);
 429         }
 430
 431         state->fsp = fsp;
 432         state->in_file_id_volatile = in_file_id_volatile;
 433
 434         if (IS_IPC(smbreq->conn)) {
 435                 struct tevent_req *subreq = NULL;
 436
 437                 state->out_data = data_blob_talloc(state, NULL, in_length);
 438                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 439                         return tevent_req_post(req, ev);
 440                 }
 441
 442                 if (!fsp_is_np(fsp)) {
 443                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 444                         return tevent_req_post(req, ev);
 445                 }
 446
 447                 subreq = np_read_send(state, server_event_context(),
 448                                       fsp->fake_file_handle,
 449                                       state->out_data.data,
 450                                       state->out_data.length);
 451                 if (tevent_req_nomem(subreq, req)) {
 452                         return tevent_req_post(req, ev);
 453                 }
 454                 tevent_req_set_callback(subreq,
 455                                         smbd_smb2_read_pipe_done,
 456                                         req);
 457                 return req;
 458         }
 459
 460         if (!CHECK_READ(fsp, smbreq)) {
 461                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 462                 return tevent_req_post(req, ev);
 463         }
 464
 465         status = schedule_smb2_aio_read(fsp->conn,
 466                                 smbreq,
 467                                 fsp,
 468                                 state,
 469                                 &state->out_data,
 470                                 (SMB_OFF_T)in_offset,
 471                                 (size_t)in_length);
 472
 473         if (NT_STATUS_IS_OK(status)) {
 474                 /*
 475                  * Doing an async read. Don't
 476                  * send a "gone async" message
 477                  * as we expect this to be less
 478                  * than the client timeout period.
 479                  * JRA. FIXME for offline files..
 480                  * FIXME. Add cancel code..
 481                  */
 482                 smb2req->async = true;
 483                 return req;
 484         }
 485
 486         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 487                 /* Real error in setting up aio. Fail. */
 488                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 489                 return tevent_req_post(req, ev);
 490         }
 491
 492         /* Fallback to synchronous. */
 493
 494         init_strict_lock_struct(fsp,
 495                                 in_file_id_volatile,
 496                                 in_offset,
 497                                 in_length,
 498                                 READ_LOCK,
 499                                 &lock);
 500
 501         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 502                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 503                 return tevent_req_post(req, ev);
 504         }
 505
 506         /* Try sendfile in preference. */
 507         status = schedule_smb2_sendfile_read(smb2req, state);
 508         if (NT_STATUS_IS_OK(status)) {
 509                 tevent_req_done(req);
 510                 return tevent_req_post(req, ev);
 511         } else {
 512                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 513                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 514                         tevent_req_nterror(req, status);
 515                         return tevent_req_post(req, ev);
 516                 }
 517         }
 518
 519         /* Ok, read into memory. Allocate the out buffer. */
 520         state->out_data = data_blob_talloc(state, NULL, in_length);
 521         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 522                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 523                 return tevent_req_post(req, ev);
 524         }
 525
 526         nread = read_file(fsp,
 527                           (char *)state->out_data.data,
 528                           in_offset,
 529                           in_length);
 530
 531         saved_errno = errno;
 532
 533         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 534
 535         DEBUG(10,("smbd_smb2_read: file %s handle [0x%016llX] offset=%llu "
 536                 "len=%llu returned %lld\n",
 537                 fsp_str_dbg(fsp),
 538                 (unsigned long long)in_file_id_volatile,
 539                 (unsigned long long)in_offset,
 540                 (unsigned long long)in_length,
 541                 (long long)nread));
 542
 543         status = smb2_read_complete(req, nread, saved_errno);
 544         if (!NT_STATUS_IS_OK(status)) {
 545                 tevent_req_nterror(req, status);
 546         } else {
 547                 /* Success. */
 548                 tevent_req_done(req);
 549         }
 550         return tevent_req_post(req, ev);
 551 }
 552
 553 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 554 {
 555         struct tevent_req *req = tevent_req_callback_data(subreq,
 556                                  struct tevent_req);
 557         struct smbd_smb2_read_state *state = tevent_req_data(req,
 558                                              struct smbd_smb2_read_state);
 559         NTSTATUS status;
 560         ssize_t nread = -1;
 561         bool is_data_outstanding;
 562
 563         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 564         TALLOC_FREE(subreq);
 565         if (!NT_STATUS_IS_OK(status)) {
 566                 tevent_req_nterror(req, status);
 567                 return;
 568         }
 569
 570         if (nread == 0 && state->out_data.length != 0) {
 571                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 572                 return;
 573         }
 574
 575         state->out_data.length = nread;
 576         state->out_remaining = 0;
 577
 578         tevent_req_done(req);
 579 }
 580
 581 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 582                                     TALLOC_CTX *mem_ctx,
 583                                     DATA_BLOB *out_data,
 584                                     uint32_t *out_remaining)
 585 {
 586         NTSTATUS status;
 587         struct smbd_smb2_read_state *state = tevent_req_data(req,
 588                                              struct smbd_smb2_read_state);
 589
 590         if (tevent_req_is_nterror(req, &status)) {
 591                 tevent_req_received(req);
 592                 return status;
 593         }
 594
 595         *out_data = state->out_data;
 596         talloc_steal(mem_ctx, out_data->data);
 597         *out_remaining = state->out_remaining;
 598
 599         tevent_req_received(req);
 600         return NT_STATUS_OK;
 601 }