source3/smbd/notify.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    change notify handling
   4    Copyright (C) Andrew Tridgell 2000
   5    Copyright (C) Jeremy Allison 1994-1998
   6    Copyright (C) Volker Lendecke 2007
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/smbd.h"
  24 #include "smbd/globals.h"
  25 #include "../librpc/gen_ndr/ndr_notify.h"
  26 #include "librpc/gen_ndr/ndr_file_id.h"
  27
  28 struct notify_change_event {
  29         struct timespec when;
  30         uint32_t action;
  31         const char *name;
  32 };
  33
  34 struct notify_change_buf {
  35         /*
  36          * If no requests are pending, changes are queued here. Simple array,
  37          * we only append.
  38          */
  39
  40         /*
  41          * num_changes == -1 means that we have got a catch-all change, when
  42          * asked we just return NT_STATUS_OK without specific changes.
  43          */
  44         int num_changes;
  45         struct notify_change_event *changes;
  46
  47         /*
  48          * If no changes are around requests are queued here. Using a linked
  49          * list, because we have to append at the end and delete from the top.
  50          */
  51         struct notify_change_request *requests;
  52 };
  53
  54 struct notify_change_request {
  55         struct notify_change_request *prev, *next;
  56         struct files_struct *fsp;       /* backpointer for cancel by mid */
  57         struct smb_request *req;
  58         uint32_t filter;
  59         uint32_t max_param;
  60         void (*reply_fn)(struct smb_request *req,
  61                          NTSTATUS error_code,
  62                          uint8_t *buf, size_t len);
  63         struct notify_mid_map *mid_map;
  64         void *backend_data;
  65 };
  66
  67 static void notify_fsp(files_struct *fsp, struct timespec when,
  68                        uint32_t action, const char *name);
  69
  70 bool change_notify_fsp_has_changes(struct files_struct *fsp)
  71 {
  72         if (fsp == NULL) {
  73                 return false;
  74         }
  75
  76         if (fsp->notify == NULL) {
  77                 return false;
  78         }
  79
  80         if (fsp->notify->num_changes == 0) {
  81                 return false;
  82         }
  83
  84         return true;
  85 }
  86
  87 /*
  88  * For NTCancel, we need to find the notify_change_request indexed by
  89  * mid. Separate list here.
  90  */
  91
  92 struct notify_mid_map {
  93         struct notify_mid_map *prev, *next;
  94         struct notify_change_request *req;
  95         uint64_t mid;
  96 };
  97
  98 static bool notify_change_record_identical(struct notify_change_event *c1,
  99                                            struct notify_change_event *c2)
 100 {
 101         /* Note this is deliberately case sensitive. */
 102         if (c1->action == c2->action &&
 103                         strcmp(c1->name, c2->name) == 0) {
 104                 return True;
 105         }
 106         return False;
 107 }
 108
 109 static int compare_notify_change_events(const void *p1, const void *p2)
 110 {
 111         const struct notify_change_event *e1 = p1;
 112         const struct notify_change_event *e2 = p2;
 113
 114         return timespec_compare(&e1->when, &e2->when);
 115 }
 116
 117 static bool notify_marshall_changes(int num_changes,
 118                                 uint32_t max_offset,
 119                                 struct notify_change_event *changes,
 120                                 DATA_BLOB *final_blob)
 121 {
 122         int i;
 123
 124         if (num_changes == -1) {
 125                 return false;
 126         }
 127
 128         /*
 129          * Sort the notifies by timestamp when the event happened to avoid
 130          * coalescing and thus dropping events.
 131          */
 132
 133         qsort(changes, num_changes,
 134               sizeof(*changes), compare_notify_change_events);
 135
 136         for (i=0; i<num_changes; i++) {
 137                 enum ndr_err_code ndr_err;
 138                 struct notify_change_event *c;
 139                 struct FILE_NOTIFY_INFORMATION m;
 140                 DATA_BLOB blob;
 141                 uint16_t pad = 0;
 142
 143                 /* Coalesce any identical records. */
 144                 while (i+1 < num_changes &&
 145                         notify_change_record_identical(&changes[i],
 146                                                 &changes[i+1])) {
 147                         i++;
 148                 }
 149
 150                 c = &changes[i];
 151
 152                 m.FileName1 = c->name;
 153                 m.FileNameLength = strlen_m(c->name)*2;
 154                 m.Action = c->action;
 155
 156                 m._pad = data_blob_null;
 157
 158                 /*
 159                  * Offset to next entry, only if there is one
 160                  */
 161
 162                 if (i == (num_changes-1)) {
 163                         m.NextEntryOffset = 0;
 164                 } else {
 165                         if ((m.FileNameLength % 4) == 2) {
 166                                 m._pad = data_blob_const(&pad, 2);
 167                         }
 168                         m.NextEntryOffset =
 169                                 ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
 170                 }
 171
 172                 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
 173                         (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
 174                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 175                         return false;
 176                 }
 177
 178                 if (DEBUGLEVEL >= 10) {
 179                         NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
 180                 }
 181
 182                 if (!data_blob_append(talloc_tos(), final_blob,
 183                                       blob.data, blob.length)) {
 184                         data_blob_free(&blob);
 185                         return false;
 186                 }
 187
 188                 data_blob_free(&blob);
 189
 190                 if (final_blob->length > max_offset) {
 191                         /* Too much data for client. */
 192                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 193                                    "marshall %d bytes\n", (int)max_offset,
 194                                    (int)final_blob->length));
 195                         return False;
 196                 }
 197         }
 198
 199         return True;
 200 }
 201
 202 /****************************************************************************
 203  Setup the common parts of the return packet and send it.
 204 *****************************************************************************/
 205
 206 void change_notify_reply(struct smb_request *req,
 207                          NTSTATUS error_code,
 208                          uint32_t max_param,
 209                          struct notify_change_buf *notify_buf,
 210                          void (*reply_fn)(struct smb_request *req,
 211                                           NTSTATUS error_code,
 212                                           uint8_t *buf, size_t len))
 213 {
 214         DATA_BLOB blob = data_blob_null;
 215
 216         if (!NT_STATUS_IS_OK(error_code)) {
 217                 reply_fn(req, error_code, NULL, 0);
 218                 return;
 219         }
 220
 221         if (max_param == 0 || notify_buf == NULL) {
 222                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 223                 return;
 224         }
 225
 226         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 227                                         notify_buf->changes, &blob)) {
 228                 /*
 229                  * We exceed what the client is willing to accept. Send
 230                  * nothing.
 231                  */
 232                 data_blob_free(&blob);
 233         }
 234
 235         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 236
 237         data_blob_free(&blob);
 238
 239         TALLOC_FREE(notify_buf->changes);
 240         notify_buf->num_changes = 0;
 241 }
 242
 243 static void notify_callback(void *private_data, struct timespec when,
 244                             const struct notify_event *e)
 245 {
 246         files_struct *fsp = (files_struct *)private_data;
 247         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 248         notify_fsp(fsp, when, e->action, e->path);
 249 }
 250
 251 NTSTATUS change_notify_create(struct files_struct *fsp, uint32_t filter,
 252                               bool recursive)
 253 {
 254         char *fullpath;
 255         size_t len;
 256         uint32_t subdir_filter;
 257         NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
 258
 259         if (fsp->notify != NULL) {
 260                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 261                           "fname = %s\n", fsp->fsp_name->base_name));
 262                 return NT_STATUS_INVALID_PARAMETER;
 263         }
 264
 265         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 266                 DEBUG(0, ("talloc failed\n"));
 267                 return NT_STATUS_NO_MEMORY;
 268         }
 269
 270         /* Do notify operations on the base_name. */
 271         fullpath = talloc_asprintf(
 272                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 273                 fsp->fsp_name->base_name);
 274         if (fullpath == NULL) {
 275                 DEBUG(0, ("talloc_asprintf failed\n"));
 276                 TALLOC_FREE(fsp->notify);
 277                 return NT_STATUS_NO_MEMORY;
 278         }
 279
 280         /*
 281          * Avoid /. at the end of the path name. notify can't deal with it.
 282          */
 283         len = strlen(fullpath);
 284         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 285                 fullpath[len-2] = '\0';
 286         }
 287
 288         subdir_filter = recursive ? filter : 0;
 289
 290         if ((filter != 0) || (subdir_filter != 0)) {
 291                 status = notify_add(fsp->conn->sconn->notify_ctx,
 292                                     fullpath, filter, subdir_filter,
 293                                     notify_callback, fsp);
 294         }
 295         TALLOC_FREE(fullpath);
 296         return status;
 297 }
 298
 299 NTSTATUS change_notify_add_request(struct smb_request *req,
 300                                 uint32_t max_param,
 301                                 uint32_t filter, bool recursive,
 302                                 struct files_struct *fsp,
 303                                 void (*reply_fn)(struct smb_request *req,
 304                                         NTSTATUS error_code,
 305                                         uint8_t *buf, size_t len))
 306 {
 307         struct notify_change_request *request = NULL;
 308         struct notify_mid_map *map = NULL;
 309         struct smbd_server_connection *sconn = req->sconn;
 310
 311         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 312                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 313
 314         if (!(request = talloc(NULL, struct notify_change_request))
 315             || !(map = talloc(request, struct notify_mid_map))) {
 316                 TALLOC_FREE(request);
 317                 return NT_STATUS_NO_MEMORY;
 318         }
 319
 320         request->mid_map = map;
 321         map->req = request;
 322
 323         request->req = talloc_move(request, &req);
 324         request->max_param = max_param;
 325         request->filter = filter;
 326         request->fsp = fsp;
 327         request->reply_fn = reply_fn;
 328         request->backend_data = NULL;
 329
 330         DLIST_ADD_END(fsp->notify->requests, request,
 331                       struct notify_change_request *);
 332
 333         map->mid = request->req->mid;
 334         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 335
 336         return NT_STATUS_OK;
 337 }
 338
 339 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 340                                          struct notify_change_request *remove_req)
 341 {
 342         files_struct *fsp;
 343         struct notify_change_request *req;
 344
 345         /*
 346          * Paranoia checks, the fsp referenced must must have the request in
 347          * its list of pending requests
 348          */
 349
 350         fsp = remove_req->fsp;
 351         SMB_ASSERT(fsp->notify != NULL);
 352
 353         for (req = fsp->notify->requests; req; req = req->next) {
 354                 if (req == remove_req) {
 355                         break;
 356                 }
 357         }
 358
 359         if (req == NULL) {
 360                 smb_panic("notify_req not found in fsp's requests");
 361         }
 362
 363         DLIST_REMOVE(fsp->notify->requests, req);
 364         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 365         TALLOC_FREE(req);
 366 }
 367
 368 static void smbd_notify_cancel_by_map(struct notify_mid_map *map)
 369 {
 370         struct smb_request *smbreq = map->req->req;
 371         struct smbd_server_connection *sconn = smbreq->sconn;
 372         struct smbd_smb2_request *smb2req = smbreq->smb2req;
 373         NTSTATUS notify_status = NT_STATUS_CANCELLED;
 374
 375         if (smb2req != NULL) {
 376                 if (smb2req->session == NULL) {
 377                         notify_status = STATUS_NOTIFY_CLEANUP;
 378                 } else if (!NT_STATUS_IS_OK(smb2req->session->status)) {
 379                         notify_status = STATUS_NOTIFY_CLEANUP;
 380                 }
 381                 if (smb2req->tcon == NULL) {
 382                         notify_status = STATUS_NOTIFY_CLEANUP;
 383                 } else if (!NT_STATUS_IS_OK(smb2req->tcon->status)) {
 384                         notify_status = STATUS_NOTIFY_CLEANUP;
 385                 }
 386         }
 387
 388         change_notify_reply(smbreq, notify_status,
 389                             0, NULL, map->req->reply_fn);
 390         change_notify_remove_request(sconn, map->req);
 391 }
 392
 393 /****************************************************************************
 394  Delete entries by mid from the change notify pending queue. Always send reply.
 395 *****************************************************************************/
 396
 397 void remove_pending_change_notify_requests_by_mid(
 398         struct smbd_server_connection *sconn, uint64_t mid)
 399 {
 400         struct notify_mid_map *map;
 401
 402         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 403                 if (map->mid == mid) {
 404                         break;
 405                 }
 406         }
 407
 408         if (map == NULL) {
 409                 return;
 410         }
 411
 412         smbd_notify_cancel_by_map(map);
 413 }
 414
 415 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 416 {
 417         struct smbd_server_connection *sconn = smbreq->sconn;
 418         struct notify_mid_map *map;
 419
 420         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 421                 if (map->req->req == smbreq) {
 422                         break;
 423                 }
 424         }
 425
 426         if (map == NULL) {
 427                 return;
 428         }
 429
 430         smbd_notify_cancel_by_map(map);
 431 }
 432
 433 static struct files_struct *smbd_notify_cancel_deleted_fn(
 434         struct files_struct *fsp, void *private_data)
 435 {
 436         struct file_id *fid = talloc_get_type_abort(
 437                 private_data, struct file_id);
 438
 439         if (file_id_equal(&fsp->file_id, fid)) {
 440                 remove_pending_change_notify_requests_by_fid(
 441                         fsp, NT_STATUS_DELETE_PENDING);
 442         }
 443         return NULL;
 444 }
 445
 446 void smbd_notify_cancel_deleted(struct messaging_context *msg,
 447                                 void *private_data, uint32_t msg_type,
 448                                 struct server_id server_id, DATA_BLOB *data)
 449 {
 450         struct smbd_server_connection *sconn = talloc_get_type_abort(
 451                 private_data, struct smbd_server_connection);
 452         struct file_id *fid;
 453         enum ndr_err_code ndr_err;
 454
 455         fid = talloc(talloc_tos(), struct file_id);
 456         if (fid == NULL) {
 457                 DEBUG(1, ("talloc failed\n"));
 458                 return;
 459         }
 460
 461         ndr_err = ndr_pull_struct_blob_all(
 462                 data, fid, fid, (ndr_pull_flags_fn_t)ndr_pull_file_id);
 463         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 464                 DEBUG(10, ("%s: ndr_pull_file_id failed: %s\n", __func__,
 465                            ndr_errstr(ndr_err)));
 466                 goto done;
 467         }
 468
 469         files_forall(sconn, smbd_notify_cancel_deleted_fn, fid);
 470
 471 done:
 472         TALLOC_FREE(fid);
 473 }
 474
 475 /****************************************************************************
 476  Delete entries by fnum from the change notify pending queue.
 477 *****************************************************************************/
 478
 479 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 480                                                   NTSTATUS status)
 481 {
 482         if (fsp->notify == NULL) {
 483                 return;
 484         }
 485
 486         while (fsp->notify->requests != NULL) {
 487                 change_notify_reply(fsp->notify->requests->req,
 488                                     status, 0, NULL,
 489                                     fsp->notify->requests->reply_fn);
 490                 change_notify_remove_request(fsp->conn->sconn,
 491                                              fsp->notify->requests);
 492         }
 493 }
 494
 495 void notify_fname(connection_struct *conn, uint32_t action, uint32_t filter,
 496                   const char *path)
 497 {
 498         struct notify_context *notify_ctx = conn->sconn->notify_ctx;
 499
 500         if (path[0] == '.' && path[1] == '/') {
 501                 path += 2;
 502         }
 503
 504         notify_trigger(notify_ctx, action, filter, conn->connectpath, path);
 505 }
 506
 507 static void notify_fsp(files_struct *fsp, struct timespec when,
 508                        uint32_t action, const char *name)
 509 {
 510         struct notify_change_event *change, *changes;
 511         char *tmp;
 512
 513         if (fsp->notify == NULL) {
 514                 /*
 515                  * Nobody is waiting, don't queue
 516                  */
 517                 return;
 518         }
 519
 520         /*
 521          * Someone has triggered a notify previously, queue the change for
 522          * later.
 523          */
 524
 525         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 526                 /*
 527                  * The real number depends on the client buf, just provide a
 528                  * guard against a DoS here.  If name == NULL the CN backend is
 529                  * alerting us to a problem.  Possibly dropped events.  Clear
 530                  * queued changes and send the catch-all response to the client
 531                  * if a request is pending.
 532                  */
 533                 TALLOC_FREE(fsp->notify->changes);
 534                 fsp->notify->num_changes = -1;
 535                 if (fsp->notify->requests != NULL) {
 536                         change_notify_reply(fsp->notify->requests->req,
 537                                             NT_STATUS_OK,
 538                                             fsp->notify->requests->max_param,
 539                                             fsp->notify,
 540                                             fsp->notify->requests->reply_fn);
 541                         change_notify_remove_request(fsp->conn->sconn,
 542                                                      fsp->notify->requests);
 543                 }
 544                 return;
 545         }
 546
 547         /* If we've exceeded the server side queue or received a NULL name
 548          * from the underlying CN implementation, don't queue up any more
 549          * requests until we can send a catch-all response to the client */
 550         if (fsp->notify->num_changes == -1) {
 551                 return;
 552         }
 553
 554         if (!(changes = talloc_realloc(
 555                       fsp->notify, fsp->notify->changes,
 556                       struct notify_change_event,
 557                       fsp->notify->num_changes+1))) {
 558                 DEBUG(0, ("talloc_realloc failed\n"));
 559                 return;
 560         }
 561
 562         fsp->notify->changes = changes;
 563
 564         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 565
 566         if (!(tmp = talloc_strdup(changes, name))) {
 567                 DEBUG(0, ("talloc_strdup failed\n"));
 568                 return;
 569         }
 570
 571         string_replace(tmp, '/', '\\');
 572         change->name = tmp;
 573
 574         change->when = when;
 575         change->action = action;
 576         fsp->notify->num_changes += 1;
 577
 578         if (fsp->notify->requests == NULL) {
 579                 /*
 580                  * Nobody is waiting, so don't send anything. The ot
 581                  */
 582                 return;
 583         }
 584
 585         if (action == NOTIFY_ACTION_OLD_NAME) {
 586                 /*
 587                  * We have to send the two rename events in one reply. So hold
 588                  * the first part back.
 589                  */
 590                 return;
 591         }
 592
 593         /*
 594          * Someone is waiting for the change, trigger the reply immediately.
 595          *
 596          * TODO: do we have to walk the lists of requests pending?
 597          */
 598
 599         change_notify_reply(fsp->notify->requests->req,
 600                             NT_STATUS_OK,
 601                             fsp->notify->requests->max_param,
 602                             fsp->notify,
 603                             fsp->notify->requests->reply_fn);
 604
 605         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 606 }
 607
 608 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32_t filter)
 609 {
 610         char *result = NULL;
 611
 612         result = talloc_strdup(mem_ctx, "");
 613
 614         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 615                 result = talloc_asprintf_append(result, "FILE_NAME|");
 616         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 617                 result = talloc_asprintf_append(result, "DIR_NAME|");
 618         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 619                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 620         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 621                 result = talloc_asprintf_append(result, "SIZE|");
 622         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 623                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 624         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 625                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 626         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 627                 result = talloc_asprintf_append(result, "CREATION|");
 628         if (filter & FILE_NOTIFY_CHANGE_EA)
 629                 result = talloc_asprintf_append(result, "EA|");
 630         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 631                 result = talloc_asprintf_append(result, "SECURITY|");
 632         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 633                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 634         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 635                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 636         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 637                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 638
 639         if (result == NULL) return NULL;
 640         if (*result == '\0') return result;
 641
 642         result[strlen(result)-1] = '\0';
 643         return result;
 644 }
 645
 646 struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
 647                                                      struct tevent_context *ev)
 648 {
 649         struct sys_notify_context *ctx;
 650
 651         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 652                 DEBUG(0, ("talloc failed\n"));
 653                 return NULL;
 654         }
 655
 656         ctx->ev = ev;
 657         ctx->private_data = NULL;
 658         return ctx;
 659 }