source3/smbd/smb2_read.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Core SMB2 server
   4
   5    Copyright (C) Stefan Metzmacher 2009
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "system/filesys.h"
  23 #include "smbd/smbd.h"
  24 #include "smbd/globals.h"
  25 #include "../libcli/smb/smb_common.h"
  26 #include "libcli/security/security.h"
  27 #include "../lib/util/tevent_ntstatus.h"
  28 #include "rpc_server/srv_pipe_hnd.h"
  29
  30 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
  31                                               struct tevent_context *ev,
  32                                               struct smbd_smb2_request *smb2req,
  33                                               struct files_struct *in_fsp,
  34                                               uint32_t in_smbpid,
  35                                               uint32_t in_length,
  36                                               uint64_t in_offset,
  37                                               uint32_t in_minimum,
  38                                               uint32_t in_remaining);
  39 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
  40                                     TALLOC_CTX *mem_ctx,
  41                                     DATA_BLOB *out_data,
  42                                     uint32_t *out_remaining);
  43
  44 static void smbd_smb2_request_read_done(struct tevent_req *subreq);
  45 NTSTATUS smbd_smb2_request_process_read(struct smbd_smb2_request *req)
  46 {
  47         NTSTATUS status;
  48         const uint8_t *inhdr;
  49         const uint8_t *inbody;
  50         int i = req->current_idx;
  51         uint32_t in_smbpid;
  52         uint32_t in_length;
  53         uint64_t in_offset;
  54         uint64_t in_file_id_persistent;
  55         uint64_t in_file_id_volatile;
  56         struct files_struct *in_fsp;
  57         uint32_t in_minimum_count;
  58         uint32_t in_remaining_bytes;
  59         struct tevent_req *subreq;
  60
  61         status = smbd_smb2_request_verify_sizes(req, 0x31);
  62         if (!NT_STATUS_IS_OK(status)) {
  63                 return smbd_smb2_request_error(req, status);
  64         }
  65         inhdr = (const uint8_t *)req->in.vector[i+0].iov_base;
  66         inbody = (const uint8_t *)req->in.vector[i+1].iov_base;
  67
  68         in_smbpid = IVAL(inhdr, SMB2_HDR_PID);
  69
  70         in_length               = IVAL(inbody, 0x04);
  71         in_offset               = BVAL(inbody, 0x08);
  72         in_file_id_persistent   = BVAL(inbody, 0x10);
  73         in_file_id_volatile     = BVAL(inbody, 0x18);
  74         in_minimum_count        = IVAL(inbody, 0x20);
  75         in_remaining_bytes      = IVAL(inbody, 0x28);
  76
  77         /* check the max read size */
  78         if (in_length > req->sconn->smb2.max_read) {
  79                 DEBUG(2,("smbd_smb2_request_process_read: "
  80                          "client ignored max read: %s: 0x%08X: 0x%08X\n",
  81                         __location__, in_length, req->sconn->smb2.max_read));
  82                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  83         }
  84
  85         status = smbd_smb2_request_verify_creditcharge(req, in_length);
  86         if (!NT_STATUS_IS_OK(status)) {
  87                 return smbd_smb2_request_error(req, status);
  88         }
  89
  90         in_fsp = file_fsp_smb2(req, in_file_id_persistent, in_file_id_volatile);
  91         if (in_fsp == NULL) {
  92                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  93         }
  94
  95         subreq = smbd_smb2_read_send(req, req->sconn->ev_ctx,
  96                                      req, in_fsp,
  97                                      in_smbpid,
  98                                      in_length,
  99                                      in_offset,
 100                                      in_minimum_count,
 101                                      in_remaining_bytes);
 102         if (subreq == NULL) {
 103                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 104         }
 105         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
 106
 107         return smbd_smb2_request_pending_queue(req, subreq, 500);
 108 }
 109
 110 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 111 {
 112         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 113                                         struct smbd_smb2_request);
 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         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         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                                 fsp->fnum,
 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(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 bool smbd_smb2_read_cancel(struct tevent_req *req)
 368 {
 369         struct smbd_smb2_read_state *state =
 370                 tevent_req_data(req,
 371                 struct smbd_smb2_read_state);
 372
 373         state->smb2req->cancelled = true;
 374
 375         return cancel_smb2_aio(state->smbreq);
 376 }
 377
 378 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 379                                               struct tevent_context *ev,
 380                                               struct smbd_smb2_request *smb2req,
 381                                               struct files_struct *fsp,
 382                                               uint32_t in_smbpid,
 383                                               uint32_t in_length,
 384                                               uint64_t in_offset,
 385                                               uint32_t in_minimum,
 386                                               uint32_t in_remaining)
 387 {
 388         NTSTATUS status;
 389         struct tevent_req *req = NULL;
 390         struct smbd_smb2_read_state *state = NULL;
 391         struct smb_request *smbreq = NULL;
 392         connection_struct *conn = smb2req->tcon->compat_conn;
 393         ssize_t nread = -1;
 394         struct lock_struct lock;
 395         int saved_errno;
 396
 397         req = tevent_req_create(mem_ctx, &state,
 398                                 struct smbd_smb2_read_state);
 399         if (req == NULL) {
 400                 return NULL;
 401         }
 402         state->smb2req = smb2req;
 403         state->in_length = in_length;
 404         state->in_offset = in_offset;
 405         state->in_minimum = in_minimum;
 406         state->out_data = data_blob_null;
 407         state->out_remaining = 0;
 408
 409         DEBUG(10,("smbd_smb2_read: %s - fnum[%d]\n",
 410                   fsp_str_dbg(fsp), fsp->fnum));
 411
 412         smbreq = smbd_smb2_fake_smb_request(smb2req);
 413         if (tevent_req_nomem(smbreq, req)) {
 414                 return tevent_req_post(req, ev);
 415         }
 416         state->smbreq = smbreq;
 417
 418         if (fsp->is_directory) {
 419                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 420                 return tevent_req_post(req, ev);
 421         }
 422
 423         state->fsp = fsp;
 424
 425         if (IS_IPC(smbreq->conn)) {
 426                 struct tevent_req *subreq = NULL;
 427
 428                 state->out_data = data_blob_talloc(state, NULL, in_length);
 429                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 430                         return tevent_req_post(req, ev);
 431                 }
 432
 433                 if (!fsp_is_np(fsp)) {
 434                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 435                         return tevent_req_post(req, ev);
 436                 }
 437
 438                 subreq = np_read_send(state, ev,
 439                                       fsp->fake_file_handle,
 440                                       state->out_data.data,
 441                                       state->out_data.length);
 442                 if (tevent_req_nomem(subreq, req)) {
 443                         return tevent_req_post(req, ev);
 444                 }
 445                 tevent_req_set_callback(subreq,
 446                                         smbd_smb2_read_pipe_done,
 447                                         req);
 448                 return req;
 449         }
 450
 451         if (!CHECK_READ(fsp, smbreq)) {
 452                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 453                 return tevent_req_post(req, ev);
 454         }
 455
 456         status = schedule_smb2_aio_read(fsp->conn,
 457                                 smbreq,
 458                                 fsp,
 459                                 state,
 460                                 &state->out_data,
 461                                 (off_t)in_offset,
 462                                 (size_t)in_length);
 463
 464         if (NT_STATUS_IS_OK(status)) {
 465                 /*
 466                  * Doing an async read, allow this
 467                  * request to be canceled
 468                  */
 469                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
 470                 return req;
 471         }
 472
 473         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 474                 /* Real error in setting up aio. Fail. */
 475                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 476                 return tevent_req_post(req, ev);
 477         }
 478
 479         /* Fallback to synchronous. */
 480
 481         init_strict_lock_struct(fsp,
 482                                 fsp->fnum,
 483                                 in_offset,
 484                                 in_length,
 485                                 READ_LOCK,
 486                                 &lock);
 487
 488         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 489                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 490                 return tevent_req_post(req, ev);
 491         }
 492
 493         /* Try sendfile in preference. */
 494         status = schedule_smb2_sendfile_read(smb2req, state);
 495         if (NT_STATUS_IS_OK(status)) {
 496                 tevent_req_done(req);
 497                 return tevent_req_post(req, ev);
 498         } else {
 499                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 500                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 501                         tevent_req_nterror(req, status);
 502                         return tevent_req_post(req, ev);
 503                 }
 504         }
 505
 506         /* Ok, read into memory. Allocate the out buffer. */
 507         state->out_data = data_blob_talloc(state, NULL, in_length);
 508         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 509                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 510                 return tevent_req_post(req, ev);
 511         }
 512
 513         nread = read_file(fsp,
 514                           (char *)state->out_data.data,
 515                           in_offset,
 516                           in_length);
 517
 518         saved_errno = errno;
 519
 520         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 521
 522         DEBUG(10,("smbd_smb2_read: file %s fnum[%d] offset=%llu "
 523                 "len=%llu returned %lld\n",
 524                 fsp_str_dbg(fsp),
 525                 fsp->fnum,
 526                 (unsigned long long)in_offset,
 527                 (unsigned long long)in_length,
 528                 (long long)nread));
 529
 530         status = smb2_read_complete(req, nread, saved_errno);
 531         if (!NT_STATUS_IS_OK(status)) {
 532                 tevent_req_nterror(req, status);
 533         } else {
 534                 /* Success. */
 535                 tevent_req_done(req);
 536         }
 537         return tevent_req_post(req, ev);
 538 }
 539
 540 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 541 {
 542         struct tevent_req *req = tevent_req_callback_data(subreq,
 543                                  struct tevent_req);
 544         struct smbd_smb2_read_state *state = tevent_req_data(req,
 545                                              struct smbd_smb2_read_state);
 546         NTSTATUS status;
 547         ssize_t nread = -1;
 548         bool is_data_outstanding;
 549
 550         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 551         TALLOC_FREE(subreq);
 552         if (!NT_STATUS_IS_OK(status)) {
 553                 NTSTATUS old = status;
 554                 status = nt_status_np_pipe(old);
 555                 tevent_req_nterror(req, status);
 556                 return;
 557         }
 558
 559         if (nread == 0 && state->out_data.length != 0) {
 560                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 561                 return;
 562         }
 563
 564         state->out_data.length = nread;
 565         state->out_remaining = 0;
 566
 567         /*
 568          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 569          * handle it in SMB1 pipe_read_andx_done().
 570          */
 571
 572         tevent_req_done(req);
 573 }
 574
 575 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 576                                     TALLOC_CTX *mem_ctx,
 577                                     DATA_BLOB *out_data,
 578                                     uint32_t *out_remaining)
 579 {
 580         NTSTATUS status;
 581         struct smbd_smb2_read_state *state = tevent_req_data(req,
 582                                              struct smbd_smb2_read_state);
 583
 584         if (tevent_req_is_nterror(req, &status)) {
 585                 tevent_req_received(req);
 586                 return status;
 587         }
 588
 589         *out_data = state->out_data;
 590         talloc_steal(mem_ctx, out_data->data);
 591         *out_remaining = state->out_remaining;
 592
 593         tevent_req_received(req);
 594         return NT_STATUS_OK;
 595 }