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                 namelen = convert_string_allocate(
  86                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  87                         &uni_name.buffer, True);
  88                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  89                         goto fail;
  90                 }
  91
  92                 namelen -= 2;   /* Dump NULL termination */
  93
  94                 /*
  95                  * Offset to next entry, only if there is one
  96                  */
  97
  98                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
  99                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
 100
 101                 u32_tmp = c->action;
 102                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 103
 104                 u32_tmp = namelen;
 105                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 106
 107                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 108
 109                 /*
 110                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 111                  */
 112                 prs_set_offset(ps, prs_offset(ps)-2);
 113
 114                 SAFE_FREE(uni_name.buffer);
 115
 116                 if (prs_offset(ps) > max_offset) {
 117                         /* Too much data for client. */
 118                         return False;
 119                 }
 120         }
 121
 122         return True;
 123
 124  fail:
 125         SAFE_FREE(uni_name.buffer);
 126         return False;
 127 }
 128
 129 /****************************************************************************
 130  Setup the common parts of the return packet and send it.
 131 *****************************************************************************/
 132
 133 static void change_notify_reply_packet(connection_struct *conn,
 134                                 const uint8 *request_buf,
 135                                        NTSTATUS error_code)
 136 {
 137         char outbuf[smb_size+38];
 138
 139         memset(outbuf, '\0', sizeof(outbuf));
 140         construct_reply_common((char *)request_buf, outbuf);
 141
 142         ERROR_NT(error_code);
 143
 144         /*
 145          * Seems NT needs a transact command with an error code
 146          * in it. This is a longer packet than a simple error.
 147          */
 148         srv_set_message(outbuf,18,0,False);
 149
 150         show_msg(outbuf);
 151         if (!srv_send_smb(smbd_server_fd(),
 152                         outbuf,
 153                         IS_CONN_ENCRYPTED(conn)))
 154                 exit_server_cleanly("change_notify_reply_packet: srv_send_smb "
 155                                     "failed.");
 156 }
 157
 158 void change_notify_reply(connection_struct *conn,
 159                         const uint8 *request_buf, uint32 max_param,
 160                          struct notify_change_buf *notify_buf)
 161 {
 162         prs_struct ps;
 163         struct smb_request *req = NULL;
 164         uint8 tmp_request[smb_size];
 165
 166         if (notify_buf->num_changes == -1) {
 167                 change_notify_reply_packet(conn, request_buf, NT_STATUS_OK);
 168                 notify_buf->num_changes = 0;
 169                 return;
 170         }
 171
 172         prs_init_empty(&ps, NULL, MARSHALL);
 173
 174         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 175                                         notify_buf->changes, &ps)) {
 176                 /*
 177                  * We exceed what the client is willing to accept. Send
 178                  * nothing.
 179                  */
 180                 change_notify_reply_packet(conn, request_buf, NT_STATUS_OK);
 181                 goto done;
 182         }
 183
 184         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 185                 change_notify_reply_packet(conn, request_buf, NT_STATUS_NO_MEMORY);
 186                 goto done;
 187         }
 188
 189         memcpy(tmp_request, request_buf, smb_size);
 190
 191         /*
 192          * We're only interested in the header fields here
 193          */
 194
 195         smb_setlen((char *)tmp_request, smb_size);
 196         SCVAL(tmp_request, smb_wct, 0);
 197
 198         init_smb_request(req, tmp_request,0, conn->encrypted_tid);
 199
 200         send_nt_replies(conn, req, NT_STATUS_OK, prs_data_p(&ps),
 201                         prs_offset(&ps), NULL, 0);
 202
 203  done:
 204         TALLOC_FREE(req);
 205         prs_mem_free(&ps);
 206
 207         TALLOC_FREE(notify_buf->changes);
 208         notify_buf->num_changes = 0;
 209 }
 210
 211 static void notify_callback(void *private_data, const struct notify_event *e)
 212 {
 213         files_struct *fsp = (files_struct *)private_data;
 214         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 215         notify_fsp(fsp, e->action, e->path);
 216 }
 217
 218 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 219                               bool recursive)
 220 {
 221         char *fullpath;
 222         struct notify_entry e;
 223         NTSTATUS status;
 224
 225         SMB_ASSERT(fsp->notify == NULL);
 226
 227         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 228                 DEBUG(0, ("talloc failed\n"));
 229                 return NT_STATUS_NO_MEMORY;
 230         }
 231
 232         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 233                      fsp->fsp_name) == -1) {
 234                 DEBUG(0, ("asprintf failed\n"));
 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 (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 364                 DEBUG(0, ("asprintf failed\n"));
 365                 return;
 366         }
 367
 368         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 369         SAFE_FREE(fullpath);
 370 }
 371
 372 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 373 {
 374         struct notify_change *change, *changes;
 375         char *tmp;
 376
 377         if (fsp->notify == NULL) {
 378                 /*
 379                  * Nobody is waiting, don't queue
 380                  */
 381                 return;
 382         }
 383
 384         /*
 385          * Someone has triggered a notify previously, queue the change for
 386          * later.
 387          */
 388
 389         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 390                 /*
 391                  * The real number depends on the client buf, just provide a
 392                  * guard against a DoS here.
 393                  */
 394                 TALLOC_FREE(fsp->notify->changes);
 395                 fsp->notify->num_changes = -1;
 396                 return;
 397         }
 398
 399         if (fsp->notify->num_changes == -1) {
 400                 return;
 401         }
 402
 403         if (!(changes = TALLOC_REALLOC_ARRAY(
 404                       fsp->notify, fsp->notify->changes,
 405                       struct notify_change, fsp->notify->num_changes+1))) {
 406                 DEBUG(0, ("talloc_realloc failed\n"));
 407                 return;
 408         }
 409
 410         fsp->notify->changes = changes;
 411
 412         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 413
 414         if (!(tmp = talloc_strdup(changes, name))) {
 415                 DEBUG(0, ("talloc_strdup failed\n"));
 416                 return;
 417         }
 418
 419         string_replace(tmp, '/', '\\');
 420         change->name = tmp;
 421
 422         change->action = action;
 423         fsp->notify->num_changes += 1;
 424
 425         if (fsp->notify->requests == NULL) {
 426                 /*
 427                  * Nobody is waiting, so don't send anything. The ot
 428                  */
 429                 return;
 430         }
 431
 432         if (action == NOTIFY_ACTION_OLD_NAME) {
 433                 /*
 434                  * We have to send the two rename events in one reply. So hold
 435                  * the first part back.
 436                  */
 437                 return;
 438         }
 439
 440         /*
 441          * Someone is waiting for the change, trigger the reply immediately.
 442          *
 443          * TODO: do we have to walk the lists of requests pending?
 444          */
 445
 446         change_notify_reply(fsp->conn,
 447                         fsp->notify->requests->request_buf,
 448                             fsp->notify->requests->max_param,
 449                             fsp->notify);
 450
 451         change_notify_remove_request(fsp->notify->requests);
 452 }
 453
 454 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 455 {
 456         char *result = NULL;
 457
 458         result = talloc_strdup(mem_ctx, "");
 459
 460         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 461                 result = talloc_asprintf_append(result, "FILE_NAME|");
 462         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 463                 result = talloc_asprintf_append(result, "DIR_NAME|");
 464         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 465                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 466         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 467                 result = talloc_asprintf_append(result, "SIZE|");
 468         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 469                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 470         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 471                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 472         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 473                 result = talloc_asprintf_append(result, "CREATION|");
 474         if (filter & FILE_NOTIFY_CHANGE_EA)
 475                 result = talloc_asprintf_append(result, "EA|");
 476         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 477                 result = talloc_asprintf_append(result, "SECURITY|");
 478         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 479                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 480         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 481                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 482         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 483                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 484
 485         if (result == NULL) return NULL;
 486         if (*result == '\0') return result;
 487
 488         result[strlen(result)-1] = '\0';
 489         return result;
 490 }
 491
 492 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 493                                                      TALLOC_CTX *mem_ctx,
 494                                                      struct event_context *ev)
 495 {
 496         struct sys_notify_context *ctx;
 497
 498         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 499                 DEBUG(0, ("talloc failed\n"));
 500                 return NULL;
 501         }
 502
 503         ctx->ev = ev;
 504         ctx->conn = conn;
 505         ctx->private_data = NULL;
 506         return ctx;
 507 }
 508
 509 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 510                           struct notify_entry *e,
 511                           void (*callback)(struct sys_notify_context *ctx,
 512                                            void *private_data,
 513                                            struct notify_event *ev),
 514                           void *private_data, void *handle)
 515 {
 516         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 517                                     handle);
 518 }
 519