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_length,
  35                                               uint64_t in_offset,
  36                                               uint32_t in_minimum,
  37                                               uint32_t in_remaining);
  38 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
  39                                     TALLOC_CTX *mem_ctx,
  40                                     DATA_BLOB *out_data,
  41                                     uint32_t *out_remaining);
  42
  43 static void smbd_smb2_request_read_done(struct tevent_req *subreq);
  44 NTSTATUS smbd_smb2_request_process_read(struct smbd_smb2_request *req)
  45 {
  46         NTSTATUS status;
  47         const uint8_t *inbody;
  48         uint32_t in_length;
  49         uint64_t in_offset;
  50         uint64_t in_file_id_persistent;
  51         uint64_t in_file_id_volatile;
  52         struct files_struct *in_fsp;
  53         uint32_t in_minimum_count;
  54         uint32_t in_remaining_bytes;
  55         struct tevent_req *subreq;
  56
  57         status = smbd_smb2_request_verify_sizes(req, 0x31);
  58         if (!NT_STATUS_IS_OK(status)) {
  59                 return smbd_smb2_request_error(req, status);
  60         }
  61         inbody = SMBD_SMB2_IN_BODY_PTR(req);
  62
  63         in_length               = IVAL(inbody, 0x04);
  64         in_offset               = BVAL(inbody, 0x08);
  65         in_file_id_persistent   = BVAL(inbody, 0x10);
  66         in_file_id_volatile     = BVAL(inbody, 0x18);
  67         in_minimum_count        = IVAL(inbody, 0x20);
  68         in_remaining_bytes      = IVAL(inbody, 0x28);
  69
  70         /* check the max read size */
  71         if (in_length > req->sconn->smb2.max_read) {
  72                 DEBUG(2,("smbd_smb2_request_process_read: "
  73                          "client ignored max read: %s: 0x%08X: 0x%08X\n",
  74                         __location__, in_length, req->sconn->smb2.max_read));
  75                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  76         }
  77
  78         status = smbd_smb2_request_verify_creditcharge(req, in_length);
  79         if (!NT_STATUS_IS_OK(status)) {
  80                 return smbd_smb2_request_error(req, status);
  81         }
  82
  83         in_fsp = file_fsp_smb2(req, in_file_id_persistent, in_file_id_volatile);
  84         if (in_fsp == NULL) {
  85                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  86         }
  87
  88         subreq = smbd_smb2_read_send(req, req->sconn->ev_ctx,
  89                                      req, in_fsp,
  90                                      in_length,
  91                                      in_offset,
  92                                      in_minimum_count,
  93                                      in_remaining_bytes);
  94         if (subreq == NULL) {
  95                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
  96         }
  97         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
  98
  99         return smbd_smb2_request_pending_queue(req, subreq, 500);
 100 }
 101
 102 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 103 {
 104         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 105                                         struct smbd_smb2_request);
 106         DATA_BLOB outbody;
 107         DATA_BLOB outdyn;
 108         uint8_t out_data_offset;
 109         DATA_BLOB out_data_buffer = data_blob_null;
 110         uint32_t out_data_remaining = 0;
 111         NTSTATUS status;
 112         NTSTATUS error; /* transport error */
 113
 114         status = smbd_smb2_read_recv(subreq,
 115                                      req,
 116                                      &out_data_buffer,
 117                                      &out_data_remaining);
 118         TALLOC_FREE(subreq);
 119         if (!NT_STATUS_IS_OK(status)) {
 120                 error = smbd_smb2_request_error(req, status);
 121                 if (!NT_STATUS_IS_OK(error)) {
 122                         smbd_server_connection_terminate(req->sconn,
 123                                                          nt_errstr(error));
 124                         return;
 125                 }
 126                 return;
 127         }
 128
 129         out_data_offset = SMB2_HDR_BODY + 0x10;
 130
 131         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 132         if (outbody.data == NULL) {
 133                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 134                 if (!NT_STATUS_IS_OK(error)) {
 135                         smbd_server_connection_terminate(req->sconn,
 136                                                          nt_errstr(error));
 137                         return;
 138                 }
 139                 return;
 140         }
 141
 142         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 143         SCVAL(outbody.data, 0x02,
 144               out_data_offset);                 /* data offset */
 145         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 146         SIVAL(outbody.data, 0x04,
 147               out_data_buffer.length);          /* data length */
 148         SIVAL(outbody.data, 0x08,
 149               out_data_remaining);              /* data remaining */
 150         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 151
 152         outdyn = out_data_buffer;
 153
 154         error = smbd_smb2_request_done(req, outbody, &outdyn);
 155         if (!NT_STATUS_IS_OK(error)) {
 156                 smbd_server_connection_terminate(req->sconn,
 157                                                  nt_errstr(error));
 158                 return;
 159         }
 160 }
 161
 162 struct smbd_smb2_read_state {
 163         struct smbd_smb2_request *smb2req;
 164         struct smb_request *smbreq;
 165         files_struct *fsp;
 166         uint32_t in_length;
 167         uint64_t in_offset;
 168         uint32_t in_minimum;
 169         DATA_BLOB out_data;
 170         uint32_t out_remaining;
 171 };
 172
 173 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 174 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 175 {
 176         struct lock_struct lock;
 177         uint32_t in_length = state->in_length;
 178         uint64_t in_offset = state->in_offset;
 179         files_struct *fsp = state->fsp;
 180         ssize_t nread;
 181
 182         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 183                                         fsp,
 184                                         NULL,
 185                                         in_offset,
 186                                         in_length);
 187         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 188                 (int)nread,
 189                 fsp_str_dbg(fsp) ));
 190
 191         if (nread == -1) {
 192                 if (errno == ENOSYS || errno == EINTR) {
 193                         /*
 194                          * Special hack for broken systems with no working
 195                          * sendfile. Fake this up by doing read/write calls.
 196                         */
 197                         set_use_sendfile(SNUM(fsp->conn), false);
 198                         nread = fake_sendfile(fsp, in_offset, in_length);
 199                         if (nread == -1) {
 200                                 DEBUG(0,("smb2_sendfile_send_data: "
 201                                         "fake_sendfile failed for "
 202                                         "file %s (%s).\n",
 203                                         fsp_str_dbg(fsp),
 204                                         strerror(errno)));
 205                                 exit_server_cleanly("smb2_sendfile_send_data: "
 206                                         "fake_sendfile failed");
 207                         }
 208                         goto out;
 209                 }
 210
 211                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 212                         "%s (%s). Terminating\n",
 213                         fsp_str_dbg(fsp),
 214                         strerror(errno)));
 215                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 216         } else if (nread == 0) {
 217                 /*
 218                  * Some sendfile implementations return 0 to indicate
 219                  * that there was a short read, but nothing was
 220                  * actually written to the socket.  In this case,
 221                  * fallback to the normal read path so the header gets
 222                  * the correct byte count.
 223                  */
 224                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 225                         "falling back to the normal read: %s\n",
 226                         fsp_str_dbg(fsp)));
 227
 228                 nread = fake_sendfile(fsp, in_offset, in_length);
 229                 if (nread == -1) {
 230                         DEBUG(0,("smb2_sendfile_send_data: "
 231                                 "fake_sendfile failed for file "
 232                                 "%s (%s). Terminating\n",
 233                                 fsp_str_dbg(fsp),
 234                                 strerror(errno)));
 235                         exit_server_cleanly("smb2_sendfile_send_data: "
 236                                 "fake_sendfile failed");
 237                 }
 238         }
 239
 240   out:
 241
 242         if (nread < in_length) {
 243                 sendfile_short_send(fsp, nread, 0, in_length);
 244         }
 245
 246         init_strict_lock_struct(fsp,
 247                                 fsp->op->global->open_persistent_id,
 248                                 in_offset,
 249                                 in_length,
 250                                 READ_LOCK,
 251                                 &lock);
 252
 253         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 254         return 0;
 255 }
 256
 257 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 258                                         struct smbd_smb2_read_state *state)
 259 {
 260         struct smbd_smb2_read_state *state_copy = NULL;
 261         files_struct *fsp = state->fsp;
 262
 263         /*
 264          * We cannot use sendfile if...
 265          * We were not configured to do so OR
 266          * Signing is active OR
 267          * This is a compound SMB2 operation OR
 268          * fsp is a STREAM file OR
 269          * We're using a write cache OR
 270          * It's not a regular file OR
 271          * Requested offset is greater than file size OR
 272          * there's not enough data in the file.
 273          * Phew :-). Luckily this means most
 274          * reads on most normal files. JRA.
 275         */
 276
 277         if (!lp__use_sendfile(SNUM(fsp->conn)) ||
 278             smb2req->do_signing ||
 279             smb2req->do_encryption ||
 280             smb2req->in.vector_count < (2*SMBD_SMB2_NUM_IOV_PER_REQ) ||
 281             (fsp->base_fsp != NULL) ||
 282             (fsp->wcp != NULL) ||
 283             (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 284             (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 285             (fsp->fsp_name->st.st_ex_size < state->in_offset + state->in_length))
 286         {
 287                 return NT_STATUS_RETRY;
 288         }
 289
 290         /* We've already checked there's this amount of data
 291            to read. */
 292         state->out_data.length = state->in_length;
 293         state->out_remaining = 0;
 294
 295         /* Make a copy of state attached to the smb2req. Attach
 296            the destructor here as this will trigger the sendfile
 297            call when the request is destroyed. */
 298         state_copy = talloc(smb2req, struct smbd_smb2_read_state);
 299         if (!state_copy) {
 300                 return NT_STATUS_NO_MEMORY;
 301         }
 302         *state_copy = *state;
 303         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 304         return NT_STATUS_OK;
 305 }
 306
 307 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 308
 309 /*******************************************************************
 310  Common read complete processing function for both synchronous and
 311  asynchronous reads.
 312 *******************************************************************/
 313
 314 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 315 {
 316         struct smbd_smb2_read_state *state = tevent_req_data(req,
 317                                         struct smbd_smb2_read_state);
 318         files_struct *fsp = state->fsp;
 319
 320         if (nread < 0) {
 321                 NTSTATUS status = map_nt_error_from_unix(err);
 322
 323                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 324                         "Error = %s (NTSTATUS %s)\n",
 325                         fsp_str_dbg(fsp),
 326                         (int)nread,
 327                         strerror(err),
 328                         nt_errstr(status)));
 329
 330                 return status;
 331         }
 332         if (nread == 0 && state->in_length != 0) {
 333                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 334                         fsp_str_dbg(fsp)));
 335                 return NT_STATUS_END_OF_FILE;
 336         }
 337
 338         if (nread < state->in_minimum) {
 339                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 340                         "minimum requested %u. Returning end of file\n",
 341                         fsp_str_dbg(fsp),
 342                         (int)nread,
 343                         (unsigned int)state->in_minimum));
 344                 return NT_STATUS_END_OF_FILE;
 345         }
 346
 347         DEBUG(3,("smbd_smb2_read: %s, file %s, length=%lu offset=%lu read=%lu\n",
 348                 fsp_fnum_dbg(fsp),
 349                 fsp_str_dbg(fsp),
 350                 (unsigned long)state->in_length,
 351                 (unsigned long)state->in_offset,
 352                 (unsigned long)nread));
 353
 354         state->out_data.length = nread;
 355         state->out_remaining = 0;
 356
 357         return NT_STATUS_OK;
 358 }
 359
 360 static bool smbd_smb2_read_cancel(struct tevent_req *req)
 361 {
 362         struct smbd_smb2_read_state *state =
 363                 tevent_req_data(req,
 364                 struct smbd_smb2_read_state);
 365
 366         state->smb2req->cancelled = true;
 367
 368         return cancel_smb2_aio(state->smbreq);
 369 }
 370
 371 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 372                                               struct tevent_context *ev,
 373                                               struct smbd_smb2_request *smb2req,
 374                                               struct files_struct *fsp,
 375                                               uint32_t in_length,
 376                                               uint64_t in_offset,
 377                                               uint32_t in_minimum,
 378                                               uint32_t in_remaining)
 379 {
 380         NTSTATUS status;
 381         struct tevent_req *req = NULL;
 382         struct smbd_smb2_read_state *state = NULL;
 383         struct smb_request *smbreq = NULL;
 384         connection_struct *conn = smb2req->tcon->compat;
 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: %s - %s\n",
 402                   fsp_str_dbg(fsp), fsp_fnum_dbg(fsp)));
 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         state->smbreq = smbreq;
 409
 410         if (fsp->is_directory) {
 411                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 412                 return tevent_req_post(req, ev);
 413         }
 414
 415         state->fsp = fsp;
 416
 417         if (IS_IPC(smbreq->conn)) {
 418                 struct tevent_req *subreq = NULL;
 419
 420                 state->out_data = data_blob_talloc(state, NULL, in_length);
 421                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 422                         return tevent_req_post(req, ev);
 423                 }
 424
 425                 if (!fsp_is_np(fsp)) {
 426                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 427                         return tevent_req_post(req, ev);
 428                 }
 429
 430                 subreq = np_read_send(state, ev,
 431                                       fsp->fake_file_handle,
 432                                       state->out_data.data,
 433                                       state->out_data.length);
 434                 if (tevent_req_nomem(subreq, req)) {
 435                         return tevent_req_post(req, ev);
 436                 }
 437                 tevent_req_set_callback(subreq,
 438                                         smbd_smb2_read_pipe_done,
 439                                         req);
 440                 return req;
 441         }
 442
 443         if (!CHECK_READ(fsp, smbreq)) {
 444                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 445                 return tevent_req_post(req, ev);
 446         }
 447
 448         status = schedule_smb2_aio_read(fsp->conn,
 449                                 smbreq,
 450                                 fsp,
 451                                 state,
 452                                 &state->out_data,
 453                                 (off_t)in_offset,
 454                                 (size_t)in_length);
 455
 456         if (NT_STATUS_IS_OK(status)) {
 457                 /*
 458                  * Doing an async read, allow this
 459                  * request to be canceled
 460                  */
 461                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
 462                 return req;
 463         }
 464
 465         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 466                 /* Real error in setting up aio. Fail. */
 467                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 468                 return tevent_req_post(req, ev);
 469         }
 470
 471         /* Fallback to synchronous. */
 472
 473         init_strict_lock_struct(fsp,
 474                                 fsp->op->global->open_persistent_id,
 475                                 in_offset,
 476                                 in_length,
 477                                 READ_LOCK,
 478                                 &lock);
 479
 480         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 481                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 482                 return tevent_req_post(req, ev);
 483         }
 484
 485         /* Try sendfile in preference. */
 486         status = schedule_smb2_sendfile_read(smb2req, state);
 487         if (NT_STATUS_IS_OK(status)) {
 488                 tevent_req_done(req);
 489                 return tevent_req_post(req, ev);
 490         } else {
 491                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 492                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 493                         tevent_req_nterror(req, status);
 494                         return tevent_req_post(req, ev);
 495                 }
 496         }
 497
 498         /* Ok, read into memory. Allocate the out buffer. */
 499         state->out_data = data_blob_talloc(state, NULL, in_length);
 500         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 501                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 502                 return tevent_req_post(req, ev);
 503         }
 504
 505         nread = read_file(fsp,
 506                           (char *)state->out_data.data,
 507                           in_offset,
 508                           in_length);
 509
 510         saved_errno = errno;
 511
 512         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 513
 514         DEBUG(10,("smbd_smb2_read: file %s, %s, offset=%llu "
 515                 "len=%llu returned %lld\n",
 516                 fsp_str_dbg(fsp),
 517                 fsp_fnum_dbg(fsp),
 518                 (unsigned long long)in_offset,
 519                 (unsigned long long)in_length,
 520                 (long long)nread));
 521
 522         status = smb2_read_complete(req, nread, saved_errno);
 523         if (!NT_STATUS_IS_OK(status)) {
 524                 tevent_req_nterror(req, status);
 525         } else {
 526                 /* Success. */
 527                 tevent_req_done(req);
 528         }
 529         return tevent_req_post(req, ev);
 530 }
 531
 532 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 533 {
 534         struct tevent_req *req = tevent_req_callback_data(subreq,
 535                                  struct tevent_req);
 536         struct smbd_smb2_read_state *state = tevent_req_data(req,
 537                                              struct smbd_smb2_read_state);
 538         NTSTATUS status;
 539         ssize_t nread = -1;
 540         bool is_data_outstanding;
 541
 542         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 543         TALLOC_FREE(subreq);
 544         if (!NT_STATUS_IS_OK(status)) {
 545                 NTSTATUS old = status;
 546                 status = nt_status_np_pipe(old);
 547                 tevent_req_nterror(req, status);
 548                 return;
 549         }
 550
 551         if (nread == 0 && state->out_data.length != 0) {
 552                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 553                 return;
 554         }
 555
 556         state->out_data.length = nread;
 557         state->out_remaining = 0;
 558
 559         /*
 560          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 561          * handle it in SMB1 pipe_read_andx_done().
 562          */
 563
 564         tevent_req_done(req);
 565 }
 566
 567 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 568                                     TALLOC_CTX *mem_ctx,
 569                                     DATA_BLOB *out_data,
 570                                     uint32_t *out_remaining)
 571 {
 572         NTSTATUS status;
 573         struct smbd_smb2_read_state *state = tevent_req_data(req,
 574                                              struct smbd_smb2_read_state);
 575
 576         if (tevent_req_is_nterror(req, &status)) {
 577                 tevent_req_received(req);
 578                 return status;
 579         }
 580
 581         *out_data = state->out_data;
 582         talloc_steal(mem_ctx, out_data->data);
 583         *out_remaining = state->out_remaining;
 584
 585         tevent_req_received(req);
 586         return NT_STATUS_OK;
 587 }