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
 142                 /* Coalesce any identical records. */
 143                 while (i+1 < num_changes &&
 144                         notify_change_record_identical(&changes[i],
 145                                                 &changes[i+1])) {
 146                         i++;
 147                 }
 148
 149                 c = &changes[i];
 150
 151                 m.FileName1 = c->name;
 152                 m.FileNameLength = strlen_m(c->name)*2;
 153                 m.Action = c->action;
 154                 m.NextEntryOffset = (i == num_changes-1) ? 0 : ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
 155
 156                 /*
 157                  * Offset to next entry, only if there is one
 158                  */
 159
 160                 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
 161                         (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
 162                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 163                         return false;
 164                 }
 165
 166                 if (DEBUGLEVEL >= 10) {
 167                         NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
 168                 }
 169
 170                 if (!data_blob_append(talloc_tos(), final_blob,
 171                                       blob.data, blob.length)) {
 172                         data_blob_free(&blob);
 173                         return false;
 174                 }
 175
 176                 data_blob_free(&blob);
 177
 178                 if (final_blob->length > max_offset) {
 179                         /* Too much data for client. */
 180                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 181                                    "marshall %d bytes\n", (int)max_offset,
 182                                    (int)final_blob->length));
 183                         return False;
 184                 }
 185         }
 186
 187         return True;
 188 }
 189
 190 /****************************************************************************
 191  Setup the common parts of the return packet and send it.
 192 *****************************************************************************/
 193
 194 void change_notify_reply(struct smb_request *req,
 195                          NTSTATUS error_code,
 196                          uint32_t max_param,
 197                          struct notify_change_buf *notify_buf,
 198                          void (*reply_fn)(struct smb_request *req,
 199                                           NTSTATUS error_code,
 200                                           uint8_t *buf, size_t len))
 201 {
 202         DATA_BLOB blob = data_blob_null;
 203
 204         if (!NT_STATUS_IS_OK(error_code)) {
 205                 reply_fn(req, error_code, NULL, 0);
 206                 return;
 207         }
 208
 209         if (max_param == 0 || notify_buf == NULL) {
 210                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 211                 return;
 212         }
 213
 214         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 215                                         notify_buf->changes, &blob)) {
 216                 /*
 217                  * We exceed what the client is willing to accept. Send
 218                  * nothing.
 219                  */
 220                 data_blob_free(&blob);
 221         }
 222
 223         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 224
 225         data_blob_free(&blob);
 226
 227         TALLOC_FREE(notify_buf->changes);
 228         notify_buf->num_changes = 0;
 229 }
 230
 231 static void notify_callback(void *private_data, struct timespec when,
 232                             const struct notify_event *e)
 233 {
 234         files_struct *fsp = (files_struct *)private_data;
 235         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 236         notify_fsp(fsp, when, e->action, e->path);
 237 }
 238
 239 NTSTATUS change_notify_create(struct files_struct *fsp, uint32_t filter,
 240                               bool recursive)
 241 {
 242         char *fullpath;
 243         size_t len;
 244         uint32_t subdir_filter;
 245         NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
 246
 247         if (fsp->notify != NULL) {
 248                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 249                           "fname = %s\n", fsp->fsp_name->base_name));
 250                 return NT_STATUS_INVALID_PARAMETER;
 251         }
 252
 253         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 254                 DEBUG(0, ("talloc failed\n"));
 255                 return NT_STATUS_NO_MEMORY;
 256         }
 257
 258         /* Do notify operations on the base_name. */
 259         fullpath = talloc_asprintf(
 260                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 261                 fsp->fsp_name->base_name);
 262         if (fullpath == NULL) {
 263                 DEBUG(0, ("talloc_asprintf failed\n"));
 264                 TALLOC_FREE(fsp->notify);
 265                 return NT_STATUS_NO_MEMORY;
 266         }
 267
 268         /*
 269          * Avoid /. at the end of the path name. notify can't deal with it.
 270          */
 271         len = strlen(fullpath);
 272         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 273                 fullpath[len-2] = '\0';
 274         }
 275
 276         subdir_filter = recursive ? filter : 0;
 277
 278         if ((filter != 0) || (subdir_filter != 0)) {
 279                 status = notify_add(fsp->conn->sconn->notify_ctx,
 280                                     fullpath, filter, subdir_filter,
 281                                     notify_callback, fsp);
 282         }
 283         TALLOC_FREE(fullpath);
 284         return status;
 285 }
 286
 287 NTSTATUS change_notify_add_request(struct smb_request *req,
 288                                 uint32_t max_param,
 289                                 uint32_t filter, bool recursive,
 290                                 struct files_struct *fsp,
 291                                 void (*reply_fn)(struct smb_request *req,
 292                                         NTSTATUS error_code,
 293                                         uint8_t *buf, size_t len))
 294 {
 295         struct notify_change_request *request = NULL;
 296         struct notify_mid_map *map = NULL;
 297         struct smbd_server_connection *sconn = req->sconn;
 298
 299         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 300                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 301
 302         if (!(request = talloc(NULL, struct notify_change_request))
 303             || !(map = talloc(request, struct notify_mid_map))) {
 304                 TALLOC_FREE(request);
 305                 return NT_STATUS_NO_MEMORY;
 306         }
 307
 308         request->mid_map = map;
 309         map->req = request;
 310
 311         request->req = talloc_move(request, &req);
 312         request->max_param = max_param;
 313         request->filter = filter;
 314         request->fsp = fsp;
 315         request->reply_fn = reply_fn;
 316         request->backend_data = NULL;
 317
 318         DLIST_ADD_END(fsp->notify->requests, request,
 319                       struct notify_change_request *);
 320
 321         map->mid = request->req->mid;
 322         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 323
 324         return NT_STATUS_OK;
 325 }
 326
 327 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 328                                          struct notify_change_request *remove_req)
 329 {
 330         files_struct *fsp;
 331         struct notify_change_request *req;
 332
 333         /*
 334          * Paranoia checks, the fsp referenced must must have the request in
 335          * its list of pending requests
 336          */
 337
 338         fsp = remove_req->fsp;
 339         SMB_ASSERT(fsp->notify != NULL);
 340
 341         for (req = fsp->notify->requests; req; req = req->next) {
 342                 if (req == remove_req) {
 343                         break;
 344                 }
 345         }
 346
 347         if (req == NULL) {
 348                 smb_panic("notify_req not found in fsp's requests");
 349         }
 350
 351         DLIST_REMOVE(fsp->notify->requests, req);
 352         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 353         TALLOC_FREE(req);
 354 }
 355
 356 static void smbd_notify_cancel_by_map(struct notify_mid_map *map)
 357 {
 358         struct smb_request *smbreq = map->req->req;
 359         struct smbd_server_connection *sconn = smbreq->sconn;
 360         struct smbd_smb2_request *smb2req = smbreq->smb2req;
 361         NTSTATUS notify_status = NT_STATUS_CANCELLED;
 362
 363         if (smb2req != NULL) {
 364                 if (smb2req->session == NULL) {
 365                         notify_status = STATUS_NOTIFY_CLEANUP;
 366                 } else if (!NT_STATUS_IS_OK(smb2req->session->status)) {
 367                         notify_status = STATUS_NOTIFY_CLEANUP;
 368                 }
 369                 if (smb2req->tcon == NULL) {
 370                         notify_status = STATUS_NOTIFY_CLEANUP;
 371                 } else if (!NT_STATUS_IS_OK(smb2req->tcon->status)) {
 372                         notify_status = STATUS_NOTIFY_CLEANUP;
 373                 }
 374         }
 375
 376         change_notify_reply(smbreq, notify_status,
 377                             0, NULL, map->req->reply_fn);
 378         change_notify_remove_request(sconn, map->req);
 379 }
 380
 381 /****************************************************************************
 382  Delete entries by mid from the change notify pending queue. Always send reply.
 383 *****************************************************************************/
 384
 385 void remove_pending_change_notify_requests_by_mid(
 386         struct smbd_server_connection *sconn, uint64_t mid)
 387 {
 388         struct notify_mid_map *map;
 389
 390         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 391                 if (map->mid == mid) {
 392                         break;
 393                 }
 394         }
 395
 396         if (map == NULL) {
 397                 return;
 398         }
 399
 400         smbd_notify_cancel_by_map(map);
 401 }
 402
 403 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 404 {
 405         struct smbd_server_connection *sconn = smbreq->sconn;
 406         struct notify_mid_map *map;
 407
 408         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 409                 if (map->req->req == smbreq) {
 410                         break;
 411                 }
 412         }
 413
 414         if (map == NULL) {
 415                 return;
 416         }
 417
 418         smbd_notify_cancel_by_map(map);
 419 }
 420
 421 static struct files_struct *smbd_notify_cancel_deleted_fn(
 422         struct files_struct *fsp, void *private_data)
 423 {
 424         struct file_id *fid = talloc_get_type_abort(
 425                 private_data, struct file_id);
 426
 427         if (file_id_equal(&fsp->file_id, fid)) {
 428                 remove_pending_change_notify_requests_by_fid(
 429                         fsp, NT_STATUS_DELETE_PENDING);
 430         }
 431         return NULL;
 432 }
 433
 434 void smbd_notify_cancel_deleted(struct messaging_context *msg,
 435                                 void *private_data, uint32_t msg_type,
 436                                 struct server_id server_id, DATA_BLOB *data)
 437 {
 438         struct smbd_server_connection *sconn = talloc_get_type_abort(
 439                 private_data, struct smbd_server_connection);
 440         struct file_id *fid;
 441         enum ndr_err_code ndr_err;
 442
 443         fid = talloc(talloc_tos(), struct file_id);
 444         if (fid == NULL) {
 445                 DEBUG(1, ("talloc failed\n"));
 446                 return;
 447         }
 448
 449         ndr_err = ndr_pull_struct_blob_all(
 450                 data, fid, fid, (ndr_pull_flags_fn_t)ndr_pull_file_id);
 451         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 452                 DEBUG(10, ("%s: ndr_pull_file_id failed: %s\n", __func__,
 453                            ndr_errstr(ndr_err)));
 454                 goto done;
 455         }
 456
 457         files_forall(sconn, smbd_notify_cancel_deleted_fn, fid);
 458
 459 done:
 460         TALLOC_FREE(fid);
 461 }
 462
 463 /****************************************************************************
 464  Delete entries by fnum from the change notify pending queue.
 465 *****************************************************************************/
 466
 467 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 468                                                   NTSTATUS status)
 469 {
 470         if (fsp->notify == NULL) {
 471                 return;
 472         }
 473
 474         while (fsp->notify->requests != NULL) {
 475                 change_notify_reply(fsp->notify->requests->req,
 476                                     status, 0, NULL,
 477                                     fsp->notify->requests->reply_fn);
 478                 change_notify_remove_request(fsp->conn->sconn,
 479                                              fsp->notify->requests);
 480         }
 481 }
 482
 483 void notify_fname(connection_struct *conn, uint32_t action, uint32_t filter,
 484                   const char *path)
 485 {
 486         struct notify_context *notify_ctx = conn->sconn->notify_ctx;
 487
 488         if (path[0] == '.' && path[1] == '/') {
 489                 path += 2;
 490         }
 491
 492         notify_trigger(notify_ctx, action, filter, conn->connectpath, path);
 493 }
 494
 495 static void notify_fsp(files_struct *fsp, struct timespec when,
 496                        uint32_t action, const char *name)
 497 {
 498         struct notify_change_event *change, *changes;
 499         char *tmp;
 500
 501         if (fsp->notify == NULL) {
 502                 /*
 503                  * Nobody is waiting, don't queue
 504                  */
 505                 return;
 506         }
 507
 508         /*
 509          * Someone has triggered a notify previously, queue the change for
 510          * later.
 511          */
 512
 513         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 514                 /*
 515                  * The real number depends on the client buf, just provide a
 516                  * guard against a DoS here.  If name == NULL the CN backend is
 517                  * alerting us to a problem.  Possibly dropped events.  Clear
 518                  * queued changes and send the catch-all response to the client
 519                  * if a request is pending.
 520                  */
 521                 TALLOC_FREE(fsp->notify->changes);
 522                 fsp->notify->num_changes = -1;
 523                 if (fsp->notify->requests != NULL) {
 524                         change_notify_reply(fsp->notify->requests->req,
 525                                             NT_STATUS_OK,
 526                                             fsp->notify->requests->max_param,
 527                                             fsp->notify,
 528                                             fsp->notify->requests->reply_fn);
 529                         change_notify_remove_request(fsp->conn->sconn,
 530                                                      fsp->notify->requests);
 531                 }
 532                 return;
 533         }
 534
 535         /* If we've exceeded the server side queue or received a NULL name
 536          * from the underlying CN implementation, don't queue up any more
 537          * requests until we can send a catch-all response to the client */
 538         if (fsp->notify->num_changes == -1) {
 539                 return;
 540         }
 541
 542         if (!(changes = talloc_realloc(
 543                       fsp->notify, fsp->notify->changes,
 544                       struct notify_change_event,
 545                       fsp->notify->num_changes+1))) {
 546                 DEBUG(0, ("talloc_realloc failed\n"));
 547                 return;
 548         }
 549
 550         fsp->notify->changes = changes;
 551
 552         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 553
 554         if (!(tmp = talloc_strdup(changes, name))) {
 555                 DEBUG(0, ("talloc_strdup failed\n"));
 556                 return;
 557         }
 558
 559         string_replace(tmp, '/', '\\');
 560         change->name = tmp;
 561
 562         change->when = when;
 563         change->action = action;
 564         fsp->notify->num_changes += 1;
 565
 566         if (fsp->notify->requests == NULL) {
 567                 /*
 568                  * Nobody is waiting, so don't send anything. The ot
 569                  */
 570                 return;
 571         }
 572
 573         if (action == NOTIFY_ACTION_OLD_NAME) {
 574                 /*
 575                  * We have to send the two rename events in one reply. So hold
 576                  * the first part back.
 577                  */
 578                 return;
 579         }
 580
 581         /*
 582          * Someone is waiting for the change, trigger the reply immediately.
 583          *
 584          * TODO: do we have to walk the lists of requests pending?
 585          */
 586
 587         change_notify_reply(fsp->notify->requests->req,
 588                             NT_STATUS_OK,
 589                             fsp->notify->requests->max_param,
 590                             fsp->notify,
 591                             fsp->notify->requests->reply_fn);
 592
 593         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 594 }
 595
 596 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32_t filter)
 597 {
 598         char *result = NULL;
 599
 600         result = talloc_strdup(mem_ctx, "");
 601
 602         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 603                 result = talloc_asprintf_append(result, "FILE_NAME|");
 604         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 605                 result = talloc_asprintf_append(result, "DIR_NAME|");
 606         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 607                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 608         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 609                 result = talloc_asprintf_append(result, "SIZE|");
 610         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 611                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 612         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 613                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 614         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 615                 result = talloc_asprintf_append(result, "CREATION|");
 616         if (filter & FILE_NOTIFY_CHANGE_EA)
 617                 result = talloc_asprintf_append(result, "EA|");
 618         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 619                 result = talloc_asprintf_append(result, "SECURITY|");
 620         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 621                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 622         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 623                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 624         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 625                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 626
 627         if (result == NULL) return NULL;
 628         if (*result == '\0') return result;
 629
 630         result[strlen(result)-1] = '\0';
 631         return result;
 632 }
 633
 634 struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
 635                                                      struct tevent_context *ev)
 636 {
 637         struct sys_notify_context *ctx;
 638
 639         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 640                 DEBUG(0, ("talloc failed\n"));
 641                 return NULL;
 642         }
 643
 644         ctx->ev = ev;
 645         ctx->private_data = NULL;
 646         return ctx;
 647 }