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_headers;
 170         uint8_t _out_hdr_buf[NBT_HDR_SIZE + SMB2_HDR_BODY + 0x10];
 171         DATA_BLOB out_data;
 172         uint32_t out_remaining;
 173 };
 174
 175 static int smb2_smb2_read_state_deny_destructor(struct smbd_smb2_read_state *state)
 176 {
 177         return -1;
 178 }
 179
 180 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 181 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 182 {
 183         struct lock_struct lock;
 184         uint32_t in_length = state->in_length;
 185         uint64_t in_offset = state->in_offset;
 186         files_struct *fsp = state->fsp;
 187         ssize_t nread;
 188
 189         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 190                                  fsp,
 191                                  state->smb2req->queue_entry.sendfile_header,
 192                                  in_offset,
 193                                  in_length);
 194         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 195                 (int)nread,
 196                 fsp_str_dbg(fsp) ));
 197
 198         if (nread == -1) {
 199                 if (errno == ENOSYS || errno == EINTR) {
 200                         /*
 201                          * Special hack for broken systems with no working
 202                          * sendfile. Fake this up by doing read/write calls.
 203                         */
 204                         set_use_sendfile(SNUM(fsp->conn), false);
 205                         nread = fake_sendfile(fsp, in_offset, in_length);
 206                         if (nread == -1) {
 207                                 DEBUG(0,("smb2_sendfile_send_data: "
 208                                         "fake_sendfile failed for "
 209                                         "file %s (%s).\n",
 210                                         fsp_str_dbg(fsp),
 211                                         strerror(errno)));
 212                                 exit_server_cleanly("smb2_sendfile_send_data: "
 213                                         "fake_sendfile failed");
 214                         }
 215                         goto out;
 216                 }
 217
 218                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 219                         "%s (%s). Terminating\n",
 220                         fsp_str_dbg(fsp),
 221                         strerror(errno)));
 222                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 223         } else if (nread == 0) {
 224                 /*
 225                  * Some sendfile implementations return 0 to indicate
 226                  * that there was a short read, but nothing was
 227                  * actually written to the socket.  In this case,
 228                  * fallback to the normal read path so the header gets
 229                  * the correct byte count.
 230                  */
 231                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 232                         "falling back to the normal read: %s\n",
 233                         fsp_str_dbg(fsp)));
 234
 235                 nread = fake_sendfile(fsp, in_offset, in_length);
 236                 if (nread == -1) {
 237                         DEBUG(0,("smb2_sendfile_send_data: "
 238                                 "fake_sendfile failed for file "
 239                                 "%s (%s). Terminating\n",
 240                                 fsp_str_dbg(fsp),
 241                                 strerror(errno)));
 242                         exit_server_cleanly("smb2_sendfile_send_data: "
 243                                 "fake_sendfile failed");
 244                 }
 245         }
 246
 247   out:
 248
 249         if (nread < in_length) {
 250                 sendfile_short_send(fsp, nread, 0, in_length);
 251         }
 252
 253         init_strict_lock_struct(fsp,
 254                                 fsp->op->global->open_persistent_id,
 255                                 in_offset,
 256                                 in_length,
 257                                 READ_LOCK,
 258                                 &lock);
 259
 260         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 261         return 0;
 262 }
 263
 264 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 265                                         struct smbd_smb2_read_state *state)
 266 {
 267         files_struct *fsp = state->fsp;
 268
 269         /*
 270          * We cannot use sendfile if...
 271          * We were not configured to do so OR
 272          * Signing is active OR
 273          * This is a compound SMB2 operation OR
 274          * fsp is a STREAM file OR
 275          * We're using a write cache OR
 276          * It's not a regular file OR
 277          * Requested offset is greater than file size OR
 278          * there's not enough data in the file.
 279          * Phew :-). Luckily this means most
 280          * reads on most normal files. JRA.
 281         */
 282
 283         if (!lp__use_sendfile(SNUM(fsp->conn)) ||
 284             smb2req->do_signing ||
 285             smb2req->do_encryption ||
 286             smb2req->in.vector_count >= (2*SMBD_SMB2_NUM_IOV_PER_REQ) ||
 287             (fsp->base_fsp != NULL) ||
 288             (fsp->wcp != NULL) ||
 289             (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 290             (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 291             (fsp->fsp_name->st.st_ex_size < state->in_offset + state->in_length))
 292         {
 293                 return NT_STATUS_RETRY;
 294         }
 295
 296         /* We've already checked there's this amount of data
 297            to read. */
 298         state->out_data.length = state->in_length;
 299         state->out_remaining = 0;
 300
 301         state->out_headers = data_blob_const(state->_out_hdr_buf,
 302                                              sizeof(state->_out_hdr_buf));
 303         return NT_STATUS_OK;
 304 }
 305
 306 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 307
 308 /*******************************************************************
 309  Common read complete processing function for both synchronous and
 310  asynchronous reads.
 311 *******************************************************************/
 312
 313 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 314 {
 315         struct smbd_smb2_read_state *state = tevent_req_data(req,
 316                                         struct smbd_smb2_read_state);
 317         files_struct *fsp = state->fsp;
 318
 319         if (nread < 0) {
 320                 NTSTATUS status = map_nt_error_from_unix(err);
 321
 322                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 323                         "Error = %s (NTSTATUS %s)\n",
 324                         fsp_str_dbg(fsp),
 325                         (int)nread,
 326                         strerror(err),
 327                         nt_errstr(status)));
 328
 329                 return status;
 330         }
 331         if (nread == 0 && state->in_length != 0) {
 332                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 333                         fsp_str_dbg(fsp)));
 334                 return NT_STATUS_END_OF_FILE;
 335         }
 336
 337         if (nread < state->in_minimum) {
 338                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 339                         "minimum requested %u. Returning end of file\n",
 340                         fsp_str_dbg(fsp),
 341                         (int)nread,
 342                         (unsigned int)state->in_minimum));
 343                 return NT_STATUS_END_OF_FILE;
 344         }
 345
 346         DEBUG(3,("smbd_smb2_read: %s, file %s, length=%lu offset=%lu read=%lu\n",
 347                 fsp_fnum_dbg(fsp),
 348                 fsp_str_dbg(fsp),
 349                 (unsigned long)state->in_length,
 350                 (unsigned long)state->in_offset,
 351                 (unsigned long)nread));
 352
 353         state->out_data.length = nread;
 354         state->out_remaining = 0;
 355
 356         return NT_STATUS_OK;
 357 }
 358
 359 static bool smbd_smb2_read_cancel(struct tevent_req *req)
 360 {
 361         struct smbd_smb2_read_state *state =
 362                 tevent_req_data(req,
 363                 struct smbd_smb2_read_state);
 364
 365         return cancel_smb2_aio(state->smbreq);
 366 }
 367
 368 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 369                                               struct tevent_context *ev,
 370                                               struct smbd_smb2_request *smb2req,
 371                                               struct files_struct *fsp,
 372                                               uint32_t in_length,
 373                                               uint64_t in_offset,
 374                                               uint32_t in_minimum,
 375                                               uint32_t in_remaining)
 376 {
 377         NTSTATUS status;
 378         struct tevent_req *req = NULL;
 379         struct smbd_smb2_read_state *state = NULL;
 380         struct smb_request *smbreq = NULL;
 381         connection_struct *conn = smb2req->tcon->compat;
 382         ssize_t nread = -1;
 383         struct lock_struct lock;
 384         int saved_errno;
 385
 386         req = tevent_req_create(mem_ctx, &state,
 387                                 struct smbd_smb2_read_state);
 388         if (req == NULL) {
 389                 return NULL;
 390         }
 391         state->smb2req = smb2req;
 392         state->in_length = in_length;
 393         state->in_offset = in_offset;
 394         state->in_minimum = in_minimum;
 395         state->out_data = data_blob_null;
 396         state->out_remaining = 0;
 397
 398         DEBUG(10,("smbd_smb2_read: %s - %s\n",
 399                   fsp_str_dbg(fsp), fsp_fnum_dbg(fsp)));
 400
 401         smbreq = smbd_smb2_fake_smb_request(smb2req);
 402         if (tevent_req_nomem(smbreq, req)) {
 403                 return tevent_req_post(req, ev);
 404         }
 405         state->smbreq = smbreq;
 406
 407         if (fsp->is_directory) {
 408                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 409                 return tevent_req_post(req, ev);
 410         }
 411
 412         state->fsp = fsp;
 413
 414         if (IS_IPC(smbreq->conn)) {
 415                 struct tevent_req *subreq = NULL;
 416
 417                 state->out_data = data_blob_talloc(state, NULL, in_length);
 418                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 419                         return tevent_req_post(req, ev);
 420                 }
 421
 422                 if (!fsp_is_np(fsp)) {
 423                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 424                         return tevent_req_post(req, ev);
 425                 }
 426
 427                 subreq = np_read_send(state, ev,
 428                                       fsp->fake_file_handle,
 429                                       state->out_data.data,
 430                                       state->out_data.length);
 431                 if (tevent_req_nomem(subreq, req)) {
 432                         return tevent_req_post(req, ev);
 433                 }
 434                 tevent_req_set_callback(subreq,
 435                                         smbd_smb2_read_pipe_done,
 436                                         req);
 437                 return req;
 438         }
 439
 440         if (!CHECK_READ(fsp, smbreq)) {
 441                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 442                 return tevent_req_post(req, ev);
 443         }
 444
 445         status = schedule_smb2_aio_read(fsp->conn,
 446                                 smbreq,
 447                                 fsp,
 448                                 state,
 449                                 &state->out_data,
 450                                 (off_t)in_offset,
 451                                 (size_t)in_length);
 452
 453         if (NT_STATUS_IS_OK(status)) {
 454                 /*
 455                  * Doing an async read, allow this
 456                  * request to be canceled
 457                  */
 458                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
 459                 return req;
 460         }
 461
 462         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 463                 /* Real error in setting up aio. Fail. */
 464                 tevent_req_nterror(req, status);
 465                 return tevent_req_post(req, ev);
 466         }
 467
 468         /* Fallback to synchronous. */
 469
 470         init_strict_lock_struct(fsp,
 471                                 fsp->op->global->open_persistent_id,
 472                                 in_offset,
 473                                 in_length,
 474                                 READ_LOCK,
 475                                 &lock);
 476
 477         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 478                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 479                 return tevent_req_post(req, ev);
 480         }
 481
 482         /* Try sendfile in preference. */
 483         status = schedule_smb2_sendfile_read(smb2req, state);
 484         if (NT_STATUS_IS_OK(status)) {
 485                 tevent_req_done(req);
 486                 return tevent_req_post(req, ev);
 487         } else {
 488                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 489                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 490                         tevent_req_nterror(req, status);
 491                         return tevent_req_post(req, ev);
 492                 }
 493         }
 494
 495         /* Ok, read into memory. Allocate the out buffer. */
 496         state->out_data = data_blob_talloc(state, NULL, in_length);
 497         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 498                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 499                 return tevent_req_post(req, ev);
 500         }
 501
 502         nread = read_file(fsp,
 503                           (char *)state->out_data.data,
 504                           in_offset,
 505                           in_length);
 506
 507         saved_errno = errno;
 508
 509         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 510
 511         DEBUG(10,("smbd_smb2_read: file %s, %s, offset=%llu "
 512                 "len=%llu returned %lld\n",
 513                 fsp_str_dbg(fsp),
 514                 fsp_fnum_dbg(fsp),
 515                 (unsigned long long)in_offset,
 516                 (unsigned long long)in_length,
 517                 (long long)nread));
 518
 519         status = smb2_read_complete(req, nread, saved_errno);
 520         if (!NT_STATUS_IS_OK(status)) {
 521                 tevent_req_nterror(req, status);
 522         } else {
 523                 /* Success. */
 524                 tevent_req_done(req);
 525         }
 526         return tevent_req_post(req, ev);
 527 }
 528
 529 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 530 {
 531         struct tevent_req *req = tevent_req_callback_data(subreq,
 532                                  struct tevent_req);
 533         struct smbd_smb2_read_state *state = tevent_req_data(req,
 534                                              struct smbd_smb2_read_state);
 535         NTSTATUS status;
 536         ssize_t nread = -1;
 537         bool is_data_outstanding;
 538
 539         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 540         TALLOC_FREE(subreq);
 541         if (!NT_STATUS_IS_OK(status)) {
 542                 NTSTATUS old = status;
 543                 status = nt_status_np_pipe(old);
 544                 tevent_req_nterror(req, status);
 545                 return;
 546         }
 547
 548         if (nread == 0 && state->out_data.length != 0) {
 549                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 550                 return;
 551         }
 552
 553         state->out_data.length = nread;
 554         state->out_remaining = 0;
 555
 556         /*
 557          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 558          * handle it in SMB1 pipe_read_andx_done().
 559          */
 560
 561         tevent_req_done(req);
 562 }
 563
 564 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 565                                     TALLOC_CTX *mem_ctx,
 566                                     DATA_BLOB *out_data,
 567                                     uint32_t *out_remaining)
 568 {
 569         NTSTATUS status;
 570         struct smbd_smb2_read_state *state = tevent_req_data(req,
 571                                              struct smbd_smb2_read_state);
 572
 573         if (tevent_req_is_nterror(req, &status)) {
 574                 tevent_req_received(req);
 575                 return status;
 576         }
 577
 578         *out_data = state->out_data;
 579         talloc_steal(mem_ctx, out_data->data);
 580         *out_remaining = state->out_remaining;
 581
 582         if (state->out_headers.length > 0) {
 583                 talloc_steal(mem_ctx, state);
 584                 talloc_set_destructor(state, smb2_smb2_read_state_deny_destructor);
 585                 tevent_req_received(req);
 586                 state->smb2req->queue_entry.sendfile_header = &state->out_headers;
 587                 talloc_set_destructor(state, smb2_sendfile_send_data);
 588         } else {
 589                 tevent_req_received(req);
 590         }
 591
 592         return NT_STATUS_OK;
 593 }