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