source/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
  24 struct notify_change_request {
  25         struct notify_change_request *prev, *next;
  26         struct files_struct *fsp;       /* backpointer for cancel by mid */
  27         uint8 request_buf[smb_size];
  28         uint32 filter;
  29         uint32 max_param;
  30         struct notify_mid_map *mid_map;
  31         void *backend_data;
  32 };
  33
  34 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  35
  36 static struct notify_mid_map *notify_changes_by_mid;
  37
  38 /*
  39  * For NTCancel, we need to find the notify_change_request indexed by
  40  * mid. Separate list here.
  41  */
  42
  43 struct notify_mid_map {
  44         struct notify_mid_map *prev, *next;
  45         struct notify_change_request *req;
  46         uint16 mid;
  47 };
  48
  49 static bool notify_change_record_identical(struct notify_change *c1,
  50                                         struct notify_change *c2)
  51 {
  52         /* Note this is deliberately case sensitive. */
  53         if (c1->action == c2->action &&
  54                         strcmp(c1->name, c2->name) == 0) {
  55                 return True;
  56         }
  57         return False;
  58 }
  59
  60 static bool notify_marshall_changes(int num_changes,
  61                                 uint32 max_offset,
  62                                 struct notify_change *changes,
  63                                 prs_struct *ps)
  64 {
  65         int i;
  66         UNISTR uni_name;
  67
  68         uni_name.buffer = NULL;
  69
  70         for (i=0; i<num_changes; i++) {
  71                 struct notify_change *c;
  72                 size_t namelen;
  73                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  74                                  * signed/unsigned issues */
  75
  76                 /* Coalesce any identical records. */
  77                 while (i+1 < num_changes &&
  78                         notify_change_record_identical(&changes[i],
  79                                                 &changes[i+1])) {
  80                         i++;
  81                 }
  82
  83                 c = &changes[i];
  84
  85                 if (!convert_string_allocate(NULL, CH_UNIX, CH_UTF16LE,
  86                         c->name, strlen(c->name)+1, &uni_name.buffer,
  87                         &namelen, True) || (uni_name.buffer == NULL)) {
  88                         goto fail;
  89                 }
  90
  91                 namelen -= 2;   /* Dump NULL termination */
  92
  93                 /*
  94                  * Offset to next entry, only if there is one
  95                  */
  96
  97                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
  98                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
  99
 100                 u32_tmp = c->action;
 101                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 102
 103                 u32_tmp = namelen;
 104                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 105
 106                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 107
 108                 /*
 109                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 110                  */
 111                 prs_set_offset(ps, prs_offset(ps)-2);
 112
 113                 SAFE_FREE(uni_name.buffer);
 114
 115                 if (prs_offset(ps) > max_offset) {
 116                         /* Too much data for client. */
 117                         return False;
 118                 }
 119         }
 120
 121         return True;
 122
 123  fail:
 124         SAFE_FREE(uni_name.buffer);
 125         return False;
 126 }
 127
 128 /****************************************************************************
 129  Setup the common parts of the return packet and send it.
 130 *****************************************************************************/
 131
 132 static void change_notify_reply_packet(connection_struct *conn,
 133                                 const uint8 *request_buf,
 134                                        NTSTATUS error_code)
 135 {
 136         char outbuf[smb_size+38];
 137
 138         memset(outbuf, '\0', sizeof(outbuf));
 139         construct_reply_common((char *)request_buf, outbuf);
 140
 141         ERROR_NT(error_code);
 142
 143         /*
 144          * Seems NT needs a transact command with an error code
 145          * in it. This is a longer packet than a simple error.
 146          */
 147         srv_set_message(outbuf,18,0,False);
 148
 149         show_msg(outbuf);
 150         if (!srv_send_smb(smbd_server_fd(),
 151                         outbuf,
 152                         IS_CONN_ENCRYPTED(conn)))
 153                 exit_server_cleanly("change_notify_reply_packet: srv_send_smb "
 154                                     "failed.");
 155 }
 156
 157 void change_notify_reply(connection_struct *conn,
 158                         const uint8 *request_buf, uint32 max_param,
 159                          struct notify_change_buf *notify_buf)
 160 {
 161         prs_struct ps;
 162         struct smb_request *req = NULL;
 163         uint8 tmp_request[smb_size];
 164
 165         if (notify_buf->num_changes == -1) {
 166                 change_notify_reply_packet(conn, request_buf, NT_STATUS_OK);
 167                 notify_buf->num_changes = 0;
 168                 return;
 169         }
 170
 171         prs_init_empty(&ps, NULL, MARSHALL);
 172
 173         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 174                                         notify_buf->changes, &ps)) {
 175                 /*
 176                  * We exceed what the client is willing to accept. Send
 177                  * nothing.
 178                  */
 179                 change_notify_reply_packet(conn, request_buf, NT_STATUS_OK);
 180                 goto done;
 181         }
 182
 183         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 184                 change_notify_reply_packet(conn, request_buf, NT_STATUS_NO_MEMORY);
 185                 goto done;
 186         }
 187
 188         memcpy(tmp_request, request_buf, smb_size);
 189
 190         /*
 191          * We're only interested in the header fields here
 192          */
 193
 194         smb_setlen((char *)tmp_request, smb_size);
 195         SCVAL(tmp_request, smb_wct, 0);
 196
 197         init_smb_request(req, tmp_request,0, conn->encrypted_tid);
 198
 199         send_nt_replies(conn, req, NT_STATUS_OK, prs_data_p(&ps),
 200                         prs_offset(&ps), NULL, 0);
 201
 202  done:
 203         TALLOC_FREE(req);
 204         prs_mem_free(&ps);
 205
 206         TALLOC_FREE(notify_buf->changes);
 207         notify_buf->num_changes = 0;
 208 }
 209
 210 static void notify_callback(void *private_data, const struct notify_event *e)
 211 {
 212         files_struct *fsp = (files_struct *)private_data;
 213         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 214         notify_fsp(fsp, e->action, e->path);
 215 }
 216
 217 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 218                               bool recursive)
 219 {
 220         char *fullpath;
 221         struct notify_entry e;
 222         NTSTATUS status;
 223
 224         SMB_ASSERT(fsp->notify == NULL);
 225
 226         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 227                 DEBUG(0, ("talloc failed\n"));
 228                 return NT_STATUS_NO_MEMORY;
 229         }
 230
 231         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 232                      fsp->fsp_name) == -1) {
 233                 DEBUG(0, ("asprintf failed\n"));
 234                 TALLOC_FREE(fsp->notify);
 235                 return NT_STATUS_NO_MEMORY;
 236         }
 237
 238         ZERO_STRUCT(e);
 239         e.path = fullpath;
 240         e.filter = filter;
 241         e.subdir_filter = 0;
 242         if (recursive) {
 243                 e.subdir_filter = filter;
 244         }
 245
 246         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 247         SAFE_FREE(fullpath);
 248
 249         return status;
 250 }
 251
 252 NTSTATUS change_notify_add_request(const struct smb_request *req,
 253                                 uint32 max_param,
 254                                 uint32 filter, bool recursive,
 255                                 struct files_struct *fsp)
 256 {
 257         struct notify_change_request *request = NULL;
 258         struct notify_mid_map *map = NULL;
 259
 260         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 261             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 262                 SAFE_FREE(request);
 263                 return NT_STATUS_NO_MEMORY;
 264         }
 265
 266         request->mid_map = map;
 267         map->req = request;
 268
 269         memcpy(request->request_buf, req->inbuf, sizeof(request->request_buf));
 270         request->max_param = max_param;
 271         request->filter = filter;
 272         request->fsp = fsp;
 273         request->backend_data = NULL;
 274
 275         DLIST_ADD_END(fsp->notify->requests, request,
 276                       struct notify_change_request *);
 277
 278         map->mid = SVAL(req->inbuf, smb_mid);
 279         DLIST_ADD(notify_changes_by_mid, map);
 280
 281         /* Push the MID of this packet on the signing queue. */
 282         srv_defer_sign_response(SVAL(req->inbuf,smb_mid));
 283
 284         return NT_STATUS_OK;
 285 }
 286
 287 static void change_notify_remove_request(struct notify_change_request *remove_req)
 288 {
 289         files_struct *fsp;
 290         struct notify_change_request *req;
 291
 292         /*
 293          * Paranoia checks, the fsp referenced must must have the request in
 294          * its list of pending requests
 295          */
 296
 297         fsp = remove_req->fsp;
 298         SMB_ASSERT(fsp->notify != NULL);
 299
 300         for (req = fsp->notify->requests; req; req = req->next) {
 301                 if (req == remove_req) {
 302                         break;
 303                 }
 304         }
 305
 306         if (req == NULL) {
 307                 smb_panic("notify_req not found in fsp's requests");
 308         }
 309
 310         DLIST_REMOVE(fsp->notify->requests, req);
 311         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 312         SAFE_FREE(req->mid_map);
 313         TALLOC_FREE(req->backend_data);
 314         SAFE_FREE(req);
 315 }
 316
 317 /****************************************************************************
 318  Delete entries by mid from the change notify pending queue. Always send reply.
 319 *****************************************************************************/
 320
 321 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 322 {
 323         struct notify_mid_map *map;
 324
 325         for (map = notify_changes_by_mid; map; map = map->next) {
 326                 if (map->mid == mid) {
 327                         break;
 328                 }
 329         }
 330
 331         if (map == NULL) {
 332                 return;
 333         }
 334
 335         change_notify_reply_packet(map->req->fsp->conn,
 336                         map->req->request_buf, NT_STATUS_CANCELLED);
 337         change_notify_remove_request(map->req);
 338 }
 339
 340 /****************************************************************************
 341  Delete entries by fnum from the change notify pending queue.
 342 *****************************************************************************/
 343
 344 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 345                                                   NTSTATUS status)
 346 {
 347         if (fsp->notify == NULL) {
 348                 return;
 349         }
 350
 351         while (fsp->notify->requests != NULL) {
 352                 change_notify_reply_packet(fsp->conn,
 353                         fsp->notify->requests->request_buf, status);
 354                 change_notify_remove_request(fsp->notify->requests);
 355         }
 356 }
 357
 358 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 359                   const char *path)
 360 {
 361         char *fullpath;
 362
 363         if (path[0] == '.' && path[1] == '/') {
 364                 path += 2;
 365         }
 366         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 367                 DEBUG(0, ("asprintf failed\n"));
 368                 return;
 369         }
 370
 371         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 372         SAFE_FREE(fullpath);
 373 }
 374
 375 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 376 {
 377         struct notify_change *change, *changes;
 378         char *tmp;
 379
 380         if (fsp->notify == NULL) {
 381                 /*
 382                  * Nobody is waiting, don't queue
 383                  */
 384                 return;
 385         }
 386
 387         /*
 388          * Someone has triggered a notify previously, queue the change for
 389          * later.
 390          */
 391
 392         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 393                 /*
 394                  * The real number depends on the client buf, just provide a
 395                  * guard against a DoS here.
 396                  */
 397                 TALLOC_FREE(fsp->notify->changes);
 398                 fsp->notify->num_changes = -1;
 399                 return;
 400         }
 401
 402         if (fsp->notify->num_changes == -1) {
 403                 return;
 404         }
 405
 406         if (!(changes = TALLOC_REALLOC_ARRAY(
 407                       fsp->notify, fsp->notify->changes,
 408                       struct notify_change, fsp->notify->num_changes+1))) {
 409                 DEBUG(0, ("talloc_realloc failed\n"));
 410                 return;
 411         }
 412
 413         fsp->notify->changes = changes;
 414
 415         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 416
 417         if (!(tmp = talloc_strdup(changes, name))) {
 418                 DEBUG(0, ("talloc_strdup failed\n"));
 419                 return;
 420         }
 421
 422         string_replace(tmp, '/', '\\');
 423         change->name = tmp;
 424
 425         change->action = action;
 426         fsp->notify->num_changes += 1;
 427
 428         if (fsp->notify->requests == NULL) {
 429                 /*
 430                  * Nobody is waiting, so don't send anything. The ot
 431                  */
 432                 return;
 433         }
 434
 435         if (action == NOTIFY_ACTION_OLD_NAME) {
 436                 /*
 437                  * We have to send the two rename events in one reply. So hold
 438                  * the first part back.
 439                  */
 440                 return;
 441         }
 442
 443         /*
 444          * Someone is waiting for the change, trigger the reply immediately.
 445          *
 446          * TODO: do we have to walk the lists of requests pending?
 447          */
 448
 449         change_notify_reply(fsp->conn,
 450                         fsp->notify->requests->request_buf,
 451                             fsp->notify->requests->max_param,
 452                             fsp->notify);
 453
 454         change_notify_remove_request(fsp->notify->requests);
 455 }
 456
 457 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 458 {
 459         char *result = NULL;
 460
 461         result = talloc_strdup(mem_ctx, "");
 462
 463         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 464                 result = talloc_asprintf_append(result, "FILE_NAME|");
 465         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 466                 result = talloc_asprintf_append(result, "DIR_NAME|");
 467         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 468                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 469         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 470                 result = talloc_asprintf_append(result, "SIZE|");
 471         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 472                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 473         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 474                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 475         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 476                 result = talloc_asprintf_append(result, "CREATION|");
 477         if (filter & FILE_NOTIFY_CHANGE_EA)
 478                 result = talloc_asprintf_append(result, "EA|");
 479         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 480                 result = talloc_asprintf_append(result, "SECURITY|");
 481         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 482                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 483         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 484                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 485         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 486                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 487
 488         if (result == NULL) return NULL;
 489         if (*result == '\0') return result;
 490
 491         result[strlen(result)-1] = '\0';
 492         return result;
 493 }
 494
 495 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 496                                                      TALLOC_CTX *mem_ctx,
 497                                                      struct event_context *ev)
 498 {
 499         struct sys_notify_context *ctx;
 500
 501         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 502                 DEBUG(0, ("talloc failed\n"));
 503                 return NULL;
 504         }
 505
 506         ctx->ev = ev;
 507         ctx->conn = conn;
 508         ctx->private_data = NULL;
 509         return ctx;
 510 }
 511
 512 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 513                           struct notify_entry *e,
 514                           void (*callback)(struct sys_notify_context *ctx,
 515                                            void *private_data,
 516                                            struct notify_event *ev),
 517                           void *private_data, void *handle)
 518 {
 519         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 520                                     handle);
 521 }
 522