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(2,("smbd_smb2_request_process_read: "
  79                          "client ignored max read: %s: 0x%08X: 0x%08X\n",
  80                         __location__, in_length, req->sconn->smb2.max_read));
  81                 return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
  82         }
  83
  84         status = smbd_smb2_request_verify_creditcharge(req, in_length);
  85         if (!NT_STATUS_IS_OK(status)) {
  86                 return smbd_smb2_request_error(req, status);
  87         }
  88
  89         if (req->compat_chain_fsp) {
  90                 /* skip check */
  91         } else if (in_file_id_persistent != in_file_id_volatile) {
  92                 return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED);
  93         }
  94
  95         subreq = smbd_smb2_read_send(req,
  96                                      req->sconn->ev_ctx,
  97                                      req,
  98                                      in_smbpid,
  99                                      in_file_id_volatile,
 100                                      in_length,
 101                                      in_offset,
 102                                      in_minimum_count,
 103                                      in_remaining_bytes);
 104         if (subreq == NULL) {
 105                 return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 106         }
 107         tevent_req_set_callback(subreq, smbd_smb2_request_read_done, req);
 108
 109         return smbd_smb2_request_pending_queue(req, subreq, 500);
 110 }
 111
 112 static void smbd_smb2_request_read_done(struct tevent_req *subreq)
 113 {
 114         struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
 115                                         struct smbd_smb2_request);
 116         DATA_BLOB outbody;
 117         DATA_BLOB outdyn;
 118         uint8_t out_data_offset;
 119         DATA_BLOB out_data_buffer = data_blob_null;
 120         uint32_t out_data_remaining = 0;
 121         NTSTATUS status;
 122         NTSTATUS error; /* transport error */
 123
 124         status = smbd_smb2_read_recv(subreq,
 125                                      req,
 126                                      &out_data_buffer,
 127                                      &out_data_remaining);
 128         TALLOC_FREE(subreq);
 129         if (!NT_STATUS_IS_OK(status)) {
 130                 error = smbd_smb2_request_error(req, status);
 131                 if (!NT_STATUS_IS_OK(error)) {
 132                         smbd_server_connection_terminate(req->sconn,
 133                                                          nt_errstr(error));
 134                         return;
 135                 }
 136                 return;
 137         }
 138
 139         out_data_offset = SMB2_HDR_BODY + 0x10;
 140
 141         outbody = data_blob_talloc(req->out.vector, NULL, 0x10);
 142         if (outbody.data == NULL) {
 143                 error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
 144                 if (!NT_STATUS_IS_OK(error)) {
 145                         smbd_server_connection_terminate(req->sconn,
 146                                                          nt_errstr(error));
 147                         return;
 148                 }
 149                 return;
 150         }
 151
 152         SSVAL(outbody.data, 0x00, 0x10 + 1);    /* struct size */
 153         SCVAL(outbody.data, 0x02,
 154               out_data_offset);                 /* data offset */
 155         SCVAL(outbody.data, 0x03, 0);           /* reserved */
 156         SIVAL(outbody.data, 0x04,
 157               out_data_buffer.length);          /* data length */
 158         SIVAL(outbody.data, 0x08,
 159               out_data_remaining);              /* data remaining */
 160         SIVAL(outbody.data, 0x0C, 0);           /* reserved */
 161
 162         outdyn = out_data_buffer;
 163
 164         error = smbd_smb2_request_done(req, outbody, &outdyn);
 165         if (!NT_STATUS_IS_OK(error)) {
 166                 smbd_server_connection_terminate(req->sconn,
 167                                                  nt_errstr(error));
 168                 return;
 169         }
 170 }
 171
 172 struct smbd_smb2_read_state {
 173         struct smbd_smb2_request *smb2req;
 174         struct smb_request *smbreq;
 175         files_struct *fsp;
 176         uint64_t in_file_id_volatile;
 177         uint32_t in_length;
 178         uint64_t in_offset;
 179         uint32_t in_minimum;
 180         DATA_BLOB out_data;
 181         uint32_t out_remaining;
 182 };
 183
 184 /* struct smbd_smb2_read_state destructor. Send the SMB2_READ data. */
 185 static int smb2_sendfile_send_data(struct smbd_smb2_read_state *state)
 186 {
 187         struct lock_struct lock;
 188         uint32_t in_length = state->in_length;
 189         uint64_t in_offset = state->in_offset;
 190         files_struct *fsp = state->fsp;
 191         ssize_t nread;
 192
 193         nread = SMB_VFS_SENDFILE(fsp->conn->sconn->sock,
 194                                         fsp,
 195                                         NULL,
 196                                         in_offset,
 197                                         in_length);
 198         DEBUG(10,("smb2_sendfile_send_data: SMB_VFS_SENDFILE returned %d on file %s\n",
 199                 (int)nread,
 200                 fsp_str_dbg(fsp) ));
 201
 202         if (nread == -1) {
 203                 if (errno == ENOSYS || errno == EINTR) {
 204                         /*
 205                          * Special hack for broken systems with no working
 206                          * sendfile. Fake this up by doing read/write calls.
 207                         */
 208                         set_use_sendfile(SNUM(fsp->conn), false);
 209                         nread = fake_sendfile(fsp, in_offset, in_length);
 210                         if (nread == -1) {
 211                                 DEBUG(0,("smb2_sendfile_send_data: "
 212                                         "fake_sendfile failed for "
 213                                         "file %s (%s).\n",
 214                                         fsp_str_dbg(fsp),
 215                                         strerror(errno)));
 216                                 exit_server_cleanly("smb2_sendfile_send_data: "
 217                                         "fake_sendfile failed");
 218                         }
 219                         goto out;
 220                 }
 221
 222                 DEBUG(0,("smb2_sendfile_send_data: sendfile failed for file "
 223                         "%s (%s). Terminating\n",
 224                         fsp_str_dbg(fsp),
 225                         strerror(errno)));
 226                 exit_server_cleanly("smb2_sendfile_send_data: sendfile failed");
 227         } else if (nread == 0) {
 228                 /*
 229                  * Some sendfile implementations return 0 to indicate
 230                  * that there was a short read, but nothing was
 231                  * actually written to the socket.  In this case,
 232                  * fallback to the normal read path so the header gets
 233                  * the correct byte count.
 234                  */
 235                 DEBUG(3, ("send_file_readX: sendfile sent zero bytes "
 236                         "falling back to the normal read: %s\n",
 237                         fsp_str_dbg(fsp)));
 238
 239                 nread = fake_sendfile(fsp, in_offset, in_length);
 240                 if (nread == -1) {
 241                         DEBUG(0,("smb2_sendfile_send_data: "
 242                                 "fake_sendfile failed for file "
 243                                 "%s (%s). Terminating\n",
 244                                 fsp_str_dbg(fsp),
 245                                 strerror(errno)));
 246                         exit_server_cleanly("smb2_sendfile_send_data: "
 247                                 "fake_sendfile failed");
 248                 }
 249         }
 250
 251   out:
 252
 253         if (nread < in_length) {
 254                 sendfile_short_send(fsp, nread, 0, in_length);
 255         }
 256
 257         init_strict_lock_struct(fsp,
 258                                 state->in_file_id_volatile,
 259                                 in_offset,
 260                                 in_length,
 261                                 READ_LOCK,
 262                                 &lock);
 263
 264         SMB_VFS_STRICT_UNLOCK(fsp->conn, fsp, &lock);
 265         return 0;
 266 }
 267
 268 static NTSTATUS schedule_smb2_sendfile_read(struct smbd_smb2_request *smb2req,
 269                                         struct smbd_smb2_read_state *state)
 270 {
 271         struct smbd_smb2_read_state *state_copy = NULL;
 272         files_struct *fsp = state->fsp;
 273
 274         /*
 275          * We cannot use sendfile if...
 276          * We were not configured to do so OR
 277          * Signing is active OR
 278          * This is a compound SMB2 operation OR
 279          * fsp is a STREAM file OR
 280          * We're using a write cache OR
 281          * It's not a regular file OR
 282          * Requested offset is greater than file size OR
 283          * there's not enough data in the file.
 284          * Phew :-). Luckily this means most
 285          * reads on most normal files. JRA.
 286         */
 287
 288         if (!lp__use_sendfile(SNUM(fsp->conn)) ||
 289                         smb2req->do_signing ||
 290                         smb2req->in.vector_count != 4 ||
 291                         (fsp->base_fsp != NULL) ||
 292                         (fsp->wcp != NULL) ||
 293                         (!S_ISREG(fsp->fsp_name->st.st_ex_mode)) ||
 294                         (state->in_offset >= fsp->fsp_name->st.st_ex_size) ||
 295                         (fsp->fsp_name->st.st_ex_size < state->in_offset +
 296                                 state->in_length)) {
 297                 return NT_STATUS_RETRY;
 298         }
 299
 300         /* We've already checked there's this amount of data
 301            to read. */
 302         state->out_data.length = state->in_length;
 303         state->out_remaining = 0;
 304
 305         /* Make a copy of state attached to the smb2req. Attach
 306            the destructor here as this will trigger the sendfile
 307            call when the request is destroyed. */
 308         state_copy = talloc(smb2req, struct smbd_smb2_read_state);
 309         if (!state_copy) {
 310                 return NT_STATUS_NO_MEMORY;
 311         }
 312         *state_copy = *state;
 313         talloc_set_destructor(state_copy, smb2_sendfile_send_data);
 314         return NT_STATUS_OK;
 315 }
 316
 317 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq);
 318
 319 /*******************************************************************
 320  Common read complete processing function for both synchronous and
 321  asynchronous reads.
 322 *******************************************************************/
 323
 324 NTSTATUS smb2_read_complete(struct tevent_req *req, ssize_t nread, int err)
 325 {
 326         struct smbd_smb2_read_state *state = tevent_req_data(req,
 327                                         struct smbd_smb2_read_state);
 328         files_struct *fsp = state->fsp;
 329
 330         if (nread < 0) {
 331                 NTSTATUS status = map_nt_error_from_unix(err);
 332
 333                 DEBUG( 3,( "smb2_read_complete: file %s nread = %d. "
 334                         "Error = %s (NTSTATUS %s)\n",
 335                         fsp_str_dbg(fsp),
 336                         (int)nread,
 337                         strerror(err),
 338                         nt_errstr(status)));
 339
 340                 return status;
 341         }
 342         if (nread == 0 && state->in_length != 0) {
 343                 DEBUG(5,("smb2_read_complete: read_file[%s] end of file\n",
 344                         fsp_str_dbg(fsp)));
 345                 return NT_STATUS_END_OF_FILE;
 346         }
 347
 348         if (nread < state->in_minimum) {
 349                 DEBUG(5,("smb2_read_complete: read_file[%s] read less %d than "
 350                         "minimum requested %u. Returning end of file\n",
 351                         fsp_str_dbg(fsp),
 352                         (int)nread,
 353                         (unsigned int)state->in_minimum));
 354                 return NT_STATUS_END_OF_FILE;
 355         }
 356
 357         DEBUG(3,("smbd_smb2_read: fnum=[%d/%s] length=%lu offset=%lu read=%lu\n",
 358                 fsp->fnum,
 359                 fsp_str_dbg(fsp),
 360                 (unsigned long)state->in_length,
 361                 (unsigned long)state->in_offset,
 362                 (unsigned long)nread));
 363
 364         state->out_data.length = nread;
 365         state->out_remaining = 0;
 366
 367         return NT_STATUS_OK;
 368 }
 369
 370 static bool smbd_smb2_read_cancel(struct tevent_req *req)
 371 {
 372         struct smbd_smb2_read_state *state =
 373                 tevent_req_data(req,
 374                 struct smbd_smb2_read_state);
 375
 376         state->smb2req->cancelled = true;
 377
 378         return cancel_smb2_aio(state->smbreq);
 379 }
 380
 381 static struct tevent_req *smbd_smb2_read_send(TALLOC_CTX *mem_ctx,
 382                                               struct tevent_context *ev,
 383                                               struct smbd_smb2_request *smb2req,
 384                                               uint32_t in_smbpid,
 385                                               uint64_t in_file_id_volatile,
 386                                               uint32_t in_length,
 387                                               uint64_t in_offset,
 388                                               uint32_t in_minimum,
 389                                               uint32_t in_remaining)
 390 {
 391         NTSTATUS status;
 392         struct tevent_req *req = NULL;
 393         struct smbd_smb2_read_state *state = NULL;
 394         struct smb_request *smbreq = NULL;
 395         connection_struct *conn = smb2req->tcon->compat_conn;
 396         files_struct *fsp = NULL;
 397         ssize_t nread = -1;
 398         struct lock_struct lock;
 399         int saved_errno;
 400
 401         req = tevent_req_create(mem_ctx, &state,
 402                                 struct smbd_smb2_read_state);
 403         if (req == NULL) {
 404                 return NULL;
 405         }
 406         state->smb2req = smb2req;
 407         state->in_length = in_length;
 408         state->in_offset = in_offset;
 409         state->in_minimum = in_minimum;
 410         state->out_data = data_blob_null;
 411         state->out_remaining = 0;
 412
 413         DEBUG(10,("smbd_smb2_read: file_id[0x%016llX]\n",
 414                   (unsigned long long)in_file_id_volatile));
 415
 416         smbreq = smbd_smb2_fake_smb_request(smb2req);
 417         if (tevent_req_nomem(smbreq, req)) {
 418                 return tevent_req_post(req, ev);
 419         }
 420         state->smbreq = smbreq;
 421
 422         fsp = file_fsp(smbreq, (uint16_t)in_file_id_volatile);
 423         if (fsp == NULL) {
 424                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 425                 return tevent_req_post(req, ev);
 426         }
 427         if (conn != fsp->conn) {
 428                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 429                 return tevent_req_post(req, ev);
 430         }
 431         if (smb2req->session->vuid != fsp->vuid) {
 432                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 433                 return tevent_req_post(req, ev);
 434         }
 435         if (fsp->is_directory) {
 436                 tevent_req_nterror(req, NT_STATUS_INVALID_DEVICE_REQUEST);
 437                 return tevent_req_post(req, ev);
 438         }
 439
 440         state->fsp = fsp;
 441         state->in_file_id_volatile = in_file_id_volatile;
 442
 443         if (IS_IPC(smbreq->conn)) {
 444                 struct tevent_req *subreq = NULL;
 445
 446                 state->out_data = data_blob_talloc(state, NULL, in_length);
 447                 if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 448                         return tevent_req_post(req, ev);
 449                 }
 450
 451                 if (!fsp_is_np(fsp)) {
 452                         tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 453                         return tevent_req_post(req, ev);
 454                 }
 455
 456                 subreq = np_read_send(state, ev,
 457                                       fsp->fake_file_handle,
 458                                       state->out_data.data,
 459                                       state->out_data.length);
 460                 if (tevent_req_nomem(subreq, req)) {
 461                         return tevent_req_post(req, ev);
 462                 }
 463                 tevent_req_set_callback(subreq,
 464                                         smbd_smb2_read_pipe_done,
 465                                         req);
 466                 return req;
 467         }
 468
 469         if (!CHECK_READ(fsp, smbreq)) {
 470                 tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED);
 471                 return tevent_req_post(req, ev);
 472         }
 473
 474         status = schedule_smb2_aio_read(fsp->conn,
 475                                 smbreq,
 476                                 fsp,
 477                                 state,
 478                                 &state->out_data,
 479                                 (off_t)in_offset,
 480                                 (size_t)in_length);
 481
 482         if (NT_STATUS_IS_OK(status)) {
 483                 /*
 484                  * Doing an async read, allow this
 485                  * request to be canceled
 486                  */
 487                 tevent_req_set_cancel_fn(req, smbd_smb2_read_cancel);
 488                 return req;
 489         }
 490
 491         if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 492                 /* Real error in setting up aio. Fail. */
 493                 tevent_req_nterror(req, NT_STATUS_FILE_CLOSED);
 494                 return tevent_req_post(req, ev);
 495         }
 496
 497         /* Fallback to synchronous. */
 498
 499         init_strict_lock_struct(fsp,
 500                                 in_file_id_volatile,
 501                                 in_offset,
 502                                 in_length,
 503                                 READ_LOCK,
 504                                 &lock);
 505
 506         if (!SMB_VFS_STRICT_LOCK(conn, fsp, &lock)) {
 507                 tevent_req_nterror(req, NT_STATUS_FILE_LOCK_CONFLICT);
 508                 return tevent_req_post(req, ev);
 509         }
 510
 511         /* Try sendfile in preference. */
 512         status = schedule_smb2_sendfile_read(smb2req, state);
 513         if (NT_STATUS_IS_OK(status)) {
 514                 tevent_req_done(req);
 515                 return tevent_req_post(req, ev);
 516         } else {
 517                 if (!NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
 518                         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 519                         tevent_req_nterror(req, status);
 520                         return tevent_req_post(req, ev);
 521                 }
 522         }
 523
 524         /* Ok, read into memory. Allocate the out buffer. */
 525         state->out_data = data_blob_talloc(state, NULL, in_length);
 526         if (in_length > 0 && tevent_req_nomem(state->out_data.data, req)) {
 527                 SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 528                 return tevent_req_post(req, ev);
 529         }
 530
 531         nread = read_file(fsp,
 532                           (char *)state->out_data.data,
 533                           in_offset,
 534                           in_length);
 535
 536         saved_errno = errno;
 537
 538         SMB_VFS_STRICT_UNLOCK(conn, fsp, &lock);
 539
 540         DEBUG(10,("smbd_smb2_read: file %s handle [0x%016llX] offset=%llu "
 541                 "len=%llu returned %lld\n",
 542                 fsp_str_dbg(fsp),
 543                 (unsigned long long)in_file_id_volatile,
 544                 (unsigned long long)in_offset,
 545                 (unsigned long long)in_length,
 546                 (long long)nread));
 547
 548         status = smb2_read_complete(req, nread, saved_errno);
 549         if (!NT_STATUS_IS_OK(status)) {
 550                 tevent_req_nterror(req, status);
 551         } else {
 552                 /* Success. */
 553                 tevent_req_done(req);
 554         }
 555         return tevent_req_post(req, ev);
 556 }
 557
 558 static void smbd_smb2_read_pipe_done(struct tevent_req *subreq)
 559 {
 560         struct tevent_req *req = tevent_req_callback_data(subreq,
 561                                  struct tevent_req);
 562         struct smbd_smb2_read_state *state = tevent_req_data(req,
 563                                              struct smbd_smb2_read_state);
 564         NTSTATUS status;
 565         ssize_t nread = -1;
 566         bool is_data_outstanding;
 567
 568         status = np_read_recv(subreq, &nread, &is_data_outstanding);
 569         TALLOC_FREE(subreq);
 570         if (!NT_STATUS_IS_OK(status)) {
 571                 NTSTATUS old = status;
 572                 status = nt_status_np_pipe(old);
 573                 tevent_req_nterror(req, status);
 574                 return;
 575         }
 576
 577         if (nread == 0 && state->out_data.length != 0) {
 578                 tevent_req_nterror(req, NT_STATUS_END_OF_FILE);
 579                 return;
 580         }
 581
 582         state->out_data.length = nread;
 583         state->out_remaining = 0;
 584
 585         /*
 586          * TODO: add STATUS_BUFFER_OVERFLOW handling, once we also
 587          * handle it in SMB1 pipe_read_andx_done().
 588          */
 589
 590         tevent_req_done(req);
 591 }
 592
 593 static NTSTATUS smbd_smb2_read_recv(struct tevent_req *req,
 594                                     TALLOC_CTX *mem_ctx,
 595                                     DATA_BLOB *out_data,
 596                                     uint32_t *out_remaining)
 597 {
 598         NTSTATUS status;
 599         struct smbd_smb2_read_state *state = tevent_req_data(req,
 600                                              struct smbd_smb2_read_state);
 601
 602         if (tevent_req_is_nterror(req, &status)) {
 603                 tevent_req_received(req);
 604                 return status;
 605         }
 606
 607         *out_data = state->out_data;
 608         talloc_steal(mem_ctx, out_data->data);
 609         *out_remaining = state->out_remaining;
 610
 611         tevent_req_received(req);
 612         return NT_STATUS_OK;
 613 }