source3/smbd/smb2_read.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Core SMB2 server
   4
   5    Copyright (C) Stefan Metzmacher 2009
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "system/filesys.h"
  23 #include "smbd/smbd.h"
  24 #include "smbd/globals.h"
  25 #include "../libcli/smb/smb_common.h"
  26 #include "libcli/security/security.h"
  27 #include "../lib/util/tevent_ntstatus.h"
  28 #include "rpc_server/srv_pipe_hnd.h"
  29
  30 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
  31                                               struct tevent_context *ev,
  32                                               struct smbd_smb2_request *smb2req,
  33                                               uint32_t in_smbpid,
  34                                               uint64_t in_file_id_volatile,
  35                                               uint32_t in_length,
  36                                               uint64_t in_offset,
  37                                               uint32_t in_minimum,
  38                                               uint32_t in_remaining);
  39 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
  40                                     TALLOC_CTX *mem_ctx,
  41                                     DATA_BLOB *out_data,
  42                                     uint32_t *out_remaining);
  43
  44 static void smbd_smb2_request_read_done(struct tevent_req *subreq);
  45 NTSTATUS smbd_smb2_request_process_read(struct smbd_smb2_request *req)
  46 {
  47         NTSTATUS status;
  48         const uint8_t *inhdr;
  49         const uint8_t *inbody;
  50         int i = req->current_idx;
  51         uint32_t in_smbpid;
  52         uint32_t in_length;
  53         uint64_t in_offset;
  54         uint64_t in_file_id_persistent;
  55         uint64_t in_file_id_volatile;
  56         uint32_t in_minimum_count;
  57         uint32_t in_remaining_bytes;
  58         struct tevent_req *subreq;
  59
  60         status = smbd_smb2_request_verify_sizes(req, 0x31);
  61         if (!NT_STATUS_IS_OK(status)) {
  62                 return smbd_smb2_request_error(req, status);
  63         }
  64         inhdr = (const uint8_t *)req->in.vector[i+0].iov_base;
  65         inbody = (const uint8_t *)req->in.vector[i+1].iov_base;
  66
  67         in_smbpid = IVAL(inhdr, SMB2_HDR_PID);
  68
  69         in_length               = IVAL(inbody, 0x04);
  70         in_offset               = BVAL(inbody, 0x08);
  71         in_file_id_persistent   = BVAL(inbody, 0x10);
  72         in_file_id_volatile     = BVAL(inbody, 0x18);
  73         in_minimum_count        = IVAL(inbody, 0x20);
  74         in_remaining_bytes      = IVAL(inbody, 0x28);
  75
  76         /* check the max read size */
  77         if (in_length > req->sconn->smb2.max_read) {
  78                 DEBUG(0,("here:%s: 0x%08X: 0x%08X\n",
  79                         __location__, in_length, req->sconn->smb2.max_read));
  80                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  81         }
  82
  83         if (req->compat_chain_fsp) {
  84                 /* skip check */
  85         } else if (in_file_id_persistent != in_file_id_volatile) {
  86                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  87         }
  88
  89         subreq = smbd_smb2_read_send(req,
  90                                      req->sconn->ev_ctx,
  91                                      req,
  92                                      in_smbpid,
  93                                      in_file_id_volatile,
  94                                      in_length,
  95                                      in_offset,
  96                                      in_minimum_count,
  97                                      in_remaining_bytes);
  98         if (subreq == NULL) {
  99                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 100         }
 101         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
 102
 103         return smbd_smb2_request_pending_queue(req, subreq, 500);
 104 }
 105
 106 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 107 {
 108         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 109                                         struct smbd_smb2_request);
 110         DATA_BLOB outbody;
 111         DATA_BLOB outdyn;
 112         uint8_t out_data_offset;
 113         DATA_BLOB out_data_buffer = data_blob_null;
 114         uint32_t out_data_remaining = 0;
 115         NTSTATUS status;
 116         NTSTATUS error; /* transport error */
 117
 118         status = smbd_smb2_read_recv(subreq,
 119                                      req,
 120                                      &out_data_buffer,
 121                                      &out_data_remaining);
 122         TALLOC_FREE(subreq);
 123         if (!NT_STATUS_IS_OK(status)) {
 124                 error = smbd_smb2_request_error(req, status);
 125                 if (!NT_STATUS_IS_OK(error)) {
 126                         smbd_server_connection_terminate(req->sconn,
 127                                                          nt_errstr(error));
 128                         return;
 129                 }
 130                 return;
 131         }
 132
 133         out_data_offset = SMB2_HDR_BODY + 0x10;
 134
 135         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 136         if (outbody.data == NULL) {
 137                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 138                 if (!NT_STATUS_IS_OK(error)) {
 139                         smbd_server_connection_terminate(req->sconn,
 140                                                          nt_errstr(error));
 141                         return;
 142                 }
 143                 return;
 144         }
 145
 146         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 147         SCVAL(outbody.data, 0x02,
 148               out_data_offset);                 /* data offset */
 149         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 150         SIVAL(outbody.data, 0x04,
 151               out_data_buffer.length);          /* data length */
 152         SIVAL(outbody.data, 0x08,
 153               out_data_remaining);              /* data remaining */
 154         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 155
 156         outdyn = out_data_buffer;
 157
 158         error = smbd_smb2_request_done(req, outbody, &outdyn);
 159         if (!NT_STATUS_IS_OK(error)) {
 160                 smbd_server_connection_terminate(req->sconn,
 161                                                  nt_errstr(error));
 162                 return;
 163         }
 164 }
 165
 166 struct smbd_smb2_read_state {
 167         struct smbd_smb2_request *smb2req;
 168         struct smb_request *smbreq;
 169         files_struct *fsp;
 170         uint64_t in_file_id_volatile;
 171         uint32_t in_length;
 172         uint64_t in_offset;
 173         uint32_t in_minimum;
 174         DATA_BLOB out_data;
 175         uint32_t out_remaining;
 176 };
 177
 178 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 179 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 180 {
 181         struct lock_struct lock;
 182         uint32_t in_length = state->in_length;
 183         uint64_t in_offset = state->in_offset;
 184         files_struct *fsp = state->fsp;
 185         ssize_t nread;
 186
 187         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 188                                         fsp,
 189                                         NULL,
 190                                         in_offset,
 191                                         in_length);
 192         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 193                 (int)nread,
 194                 fsp_str_dbg(fsp) ));
 195
 196         if (nread == -1) {
 197                 if (errno == ENOSYS || errno == EINTR) {
 198                         /*
 199                          * Special hack for broken systems with no working
 200                          * sendfile. Fake this up by doing read/write calls.
 201                         */
 202                         set_use_sendfile(SNUM(fsp->conn), false);
 203                         nread = fake_sendfile(fsp, in_offset, in_length);
 204                         if (nread == -1) {
 205                                 DEBUG(0,("smb2_sendfile_send_data: "
 206                                         "fake_sendfile failed for "
 207                                         "file %s (%s).\n",
 208                                         fsp_str_dbg(fsp),
 209                                         strerror(errno)));
 210                                 exit_server_cleanly("smb2_sendfile_send_data: "
 211                                         "fake_sendfile failed");
 212                         }
 213                         goto out;
 214                 }
 215
 216                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 217                         "%s (%s). Terminating\n",
 218                         fsp_str_dbg(fsp),
 219                         strerror(errno)));
 220                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 221         } else if (nread == 0) {
 222                 /*
 223                  * Some sendfile implementations return 0 to indicate
 224                  * that there was a short read, but nothing was
 225                  * actually written to the socket.  In this case,
 226                  * fallback to the normal read path so the header gets
 227                  * the correct byte count.
 228                  */
 229                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 230                         "falling back to the normal read: %s\n",
 231                         fsp_str_dbg(fsp)));
 232
 233                 nread = fake_sendfile(fsp, in_offset, in_length);
 234                 if (nread == -1) {
 235                         DEBUG(0,("smb2_sendfile_send_data: "
 236                                 "fake_sendfile failed for file "
 237                                 "%s (%s). Terminating\n",
 238                                 fsp_str_dbg(fsp),
 239                                 strerror(errno)));
 240                         exit_server_cleanly("smb2_sendfile_send_data: "
 241                                 "fake_sendfile failed");
 242                 }
 243         }
 244
 245   out:
 246
 247         if (nread < in_length) {
 248                 sendfile_short_send(fsp, nread, 0, in_length);
 249         }
 250
 251         init_strict_lock_struct(fsp,
 252                                 state->in_file_id_volatile,
 253                                 in_offset,
 254                                 in_length,
 255                                 READ_LOCK,
 256                                 &lock);
 257
 258         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 259         return 0;
 260 }
 261
 262 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 263                                         struct smbd_smb2_read_state *state)
 264 {
 265         struct smbd_smb2_read_state *state_copy = NULL;
 266         files_struct *fsp = state->fsp;
 267
 268         /*
 269          * We cannot use sendfile if...
 270          * We were not configured to do so OR
 271          * Signing is active OR
 272          * This is a compound SMB2 operation OR
 273          * fsp is a STREAM file OR
 274          * We're using a write cache OR
 275          * It's not a regular file OR
 276          * Requested offset is greater than file size OR
 277          * there's not enough data in the file.
 278          * Phew :-). Luckily this means most
 279          * reads on most normal files. JRA.
 280         */
 281
 282         if (!lp__use_sendfile(SNUM(fsp->conn)) ||
 283                         smb2req->do_signing ||
 284                         smb2req->in.vector_count != 4 ||
 285                         (fsp->base_fsp != NULL) ||
 286                         (fsp->wcp != NULL) ||
 287                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 288                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 289                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 290                                 state->in_length)) {
 291                 return NT_STATUS_RETRY;
 292         }
 293
 294         /* We've already checked there's this amount of data
 295            to read. */
 296         state->out_data.length = state->in_length;
 297         state->out_remaining = 0;
 298
 299         /* Make a copy of state attached to the smb2req. Attach
 300            the destructor here as this will trigger the sendfile
 301            call when the request is destroyed. */
 302         state_copy = talloc(smb2req, struct smbd_smb2_read_state);
 303         if (!state_copy) {
 304                 return NT_STATUS_NO_MEMORY;
 305         }
 306         *state_copy = *state;
 307         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 308         return NT_STATUS_OK;
 309 }
 310
 311 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 312
 313 /*******************************************************************
 314  Common read complete processing function for both synchronous and
 315  asynchronous reads.
 316 *******************************************************************/
 317
 318 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 319 {
 320         struct smbd_smb2_read_state *state = tevent_req_data(req,
 321                                         struct smbd_smb2_read_state);
 322         files_struct *fsp = state->fsp;
 323
 324         if (nread < 0) {
 325                 NTSTATUS status = map_nt_error_from_unix(err);
 326
 327                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 328                         "Error = %s (NTSTATUS %s)\n",
 329                         fsp_str_dbg(fsp),
 330                         (int)nread,
 331                         strerror(err),
 332                         nt_errstr(status)));
 333
 334                 return status;
 335         }
 336         if (nread == 0 && state->in_length != 0) {
 337                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 338                         fsp_str_dbg(fsp)));
 339                 return NT_STATUS_END_OF_FILE;
 340         }
 341
 342         if (nread < state->in_minimum) {
 343                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 344                         "minimum requested %u. Returning end of file\n",
 345                         fsp_str_dbg(fsp),
 346                         (int)nread,
 347                         (unsigned int)state->in_minimum));
 348                 return NT_STATUS_END_OF_FILE;
 349         }
 350
 351         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 352                 fsp->fnum,
 353                 fsp_str_dbg(fsp),
 354                 (unsigned long)state->in_length,
 355                 (unsigned long)state->in_offset,
 356                 (unsigned long)nread));
 357
 358         state->out_data.length = nread;
 359         state->out_remaining = 0;
 360
 361         return NT_STATUS_OK;
 362 }
 363
 364 static bool smbd_smb2_read_cancel(struct tevent_req *req)
 365 {
 366         struct smbd_smb2_read_state *state =
 367                 tevent_req_data(req,
 368                 struct smbd_smb2_read_state);
 369
 370         state->smb2req->cancelled = true;
 371
 372         return cancel_smb2_aio(state->smbreq);
 373 }
 374
 375 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 376                                               struct tevent_context *ev,
 377                                               struct smbd_smb2_request *smb2req,
 378                                               uint32_t in_smbpid,
 379                                               uint64_t in_file_id_volatile,
 380                                               uint32_t in_length,
 381                                               uint64_t in_offset,
 382                                               uint32_t in_minimum,
 383                                               uint32_t in_remaining)
 384 {
 385         NTSTATUS status;
 386         struct tevent_req *req = NULL;
 387         struct smbd_smb2_read_state *state = NULL;
 388         struct smb_request *smbreq = NULL;
 389         connection_struct *conn = smb2req->tcon->compat_conn;
 390         files_struct *fsp = NULL;
 391         ssize_t nread = -1;
 392         struct lock_struct lock;
 393         int saved_errno;
 394
 395         req = tevent_req_create(mem_ctx, &state,
 396                                 struct smbd_smb2_read_state);
 397         if (req == NULL) {
 398                 return NULL;
 399         }
 400         state->smb2req = smb2req;
 401         state->in_length = in_length;
 402         state->in_offset = in_offset;
 403         state->in_minimum = in_minimum;
 404         state->out_data = data_blob_null;
 405         state->out_remaining = 0;
 406
 407         DEBUG(10,("smbd_smb2_read: file_id[0x%016llX]\n",
 408                   (unsigned long long)in_file_id_volatile));
 409
 410         smbreq = smbd_smb2_fake_smb_request(smb2req);
 411         if (tevent_req_nomem(smbreq, req)) {
 412                 return tevent_req_post(req, ev);
 413         }
 414         state->smbreq = smbreq;
 415
 416         fsp = file_fsp(smbreq, (uint16_t)in_file_id_volatile);
 417         if (fsp == NULL) {
 418                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 419                 return tevent_req_post(req, ev);
 420         }
 421         if (conn != fsp->conn) {
 422                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 423                 return tevent_req_post(req, ev);
 424         }
 425         if (smb2req->session->vuid != fsp->vuid) {
 426                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 427                 return tevent_req_post(req, ev);
 428         }
 429         if (fsp->is_directory) {
 430                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 431                 return tevent_req_post(req, ev);
 432         }
 433
 434         state->fsp = fsp;
 435         state->in_file_id_volatile = in_file_id_volatile;
 436
 437         if (IS_IPC(smbreq->conn)) {
 438                 struct tevent_req *subreq = NULL;
 439
 440                 state->out_data = data_blob_talloc(state, NULL, in_length);
 441                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 442                         return tevent_req_post(req, ev);
 443                 }
 444
 445                 if (!fsp_is_np(fsp)) {
 446                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 447                         return tevent_req_post(req, ev);
 448                 }
 449
 450                 subreq = np_read_send(state, ev,
 451                                       fsp->fake_file_handle,
 452                                       state->out_data.data,
 453                                       state->out_data.length);
 454                 if (tevent_req_nomem(subreq, req)) {
 455                         return tevent_req_post(req, ev);
 456                 }
 457                 tevent_req_set_callback(subreq,
 458                                         smbd_smb2_read_pipe_done,
 459                                         req);
 460                 return req;
 461         }
 462
 463         if (!CHECK_READ(fsp, smbreq)) {
 464                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 465                 return tevent_req_post(req, ev);
 466         }
 467
 468         status = schedule_smb2_aio_read(fsp->conn,
 469                                 smbreq,
 470                                 fsp,
 471                                 state,
 472                                 &state->out_data,
 473                                 (SMB_OFF_T)in_offset,
 474                                 (size_t)in_length);
 475
 476         if (NT_STATUS_IS_OK(status)) {
 477                 /*
 478                  * Doing an async read, allow this
 479                  * request to be canceled
 480                  */
 481                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
 482                 return req;
 483         }
 484
 485         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 486                 /* Real error in setting up aio. Fail. */
 487                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 488                 return tevent_req_post(req, ev);
 489         }
 490
 491         /* Fallback to synchronous. */
 492
 493         init_strict_lock_struct(fsp,
 494                                 in_file_id_volatile,
 495                                 in_offset,
 496                                 in_length,
 497                                 READ_LOCK,
 498                                 &lock);
 499
 500         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 501                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 502                 return tevent_req_post(req, ev);
 503         }
 504
 505         /* Try sendfile in preference. */
 506         status = schedule_smb2_sendfile_read(smb2req, state);
 507         if (NT_STATUS_IS_OK(status)) {
 508                 tevent_req_done(req);
 509                 return tevent_req_post(req, ev);
 510         } else {
 511                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 512                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 513                         tevent_req_nterror(req, status);
 514                         return tevent_req_post(req, ev);
 515                 }
 516         }
 517
 518         /* Ok, read into memory. Allocate the out buffer. */
 519         state->out_data = data_blob_talloc(state, NULL, in_length);
 520         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 521                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 522                 return tevent_req_post(req, ev);
 523         }
 524
 525         nread = read_file(fsp,
 526                           (char *)state->out_data.data,
 527                           in_offset,
 528                           in_length);
 529
 530         saved_errno = errno;
 531
 532         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 533
 534         DEBUG(10,("smbd_smb2_read: file %s handle [0x%016llX] offset=%llu "
 535                 "len=%llu returned %lld\n",
 536                 fsp_str_dbg(fsp),
 537                 (unsigned long long)in_file_id_volatile,
 538                 (unsigned long long)in_offset,
 539                 (unsigned long long)in_length,
 540                 (long long)nread));
 541
 542         status = smb2_read_complete(req, nread, saved_errno);
 543         if (!NT_STATUS_IS_OK(status)) {
 544                 tevent_req_nterror(req, status);
 545         } else {
 546                 /* Success. */
 547                 tevent_req_done(req);
 548         }
 549         return tevent_req_post(req, ev);
 550 }
 551
 552 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 553 {
 554         struct tevent_req *req = tevent_req_callback_data(subreq,
 555                                  struct tevent_req);
 556         struct smbd_smb2_read_state *state = tevent_req_data(req,
 557                                              struct smbd_smb2_read_state);
 558         NTSTATUS status;
 559         ssize_t nread = -1;
 560         bool is_data_outstanding;
 561
 562         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 563         TALLOC_FREE(subreq);
 564         if (!NT_STATUS_IS_OK(status)) {
 565                 tevent_req_nterror(req, status);
 566                 return;
 567         }
 568
 569         if (nread == 0 && state->out_data.length != 0) {
 570                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 571                 return;
 572         }
 573
 574         state->out_data.length = nread;
 575         state->out_remaining = 0;
 576
 577         /*
 578          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 579          * handle it in SMB1 pipe_read_andx_done().
 580          */
 581
 582         tevent_req_done(req);
 583 }
 584
 585 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 586                                     TALLOC_CTX *mem_ctx,
 587                                     DATA_BLOB *out_data,
 588                                     uint32_t *out_remaining)
 589 {
 590         NTSTATUS status;
 591         struct smbd_smb2_read_state *state = tevent_req_data(req,
 592                                              struct smbd_smb2_read_state);
 593
 594         if (tevent_req_is_nterror(req, &status)) {
 595                 tevent_req_received(req);
 596                 return status;
 597         }
 598
 599         *out_data = state->out_data;
 600         talloc_steal(mem_ctx, out_data->data);
 601         *out_remaining = state->out_remaining;
 602
 603         tevent_req_received(req);
 604         return NT_STATUS_OK;
 605 }