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                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 118                                    "marshall %d bytes\n", (int)max_offset,
 119                                    (int)prs_offset(ps)));
 120                         return False;
 121                 }
 122         }
 123
 124         return True;
 125
 126  fail:
 127         SAFE_FREE(uni_name.buffer);
 128         return False;
 129 }
 130
 131 /****************************************************************************
 132  Setup the common parts of the return packet and send it.
 133 *****************************************************************************/
 134
 135 static void change_notify_reply_packet(connection_struct *conn,
 136                                 const uint8 *request_buf,
 137                                        NTSTATUS error_code)
 138 {
 139         char outbuf[smb_size+38];
 140
 141         memset(outbuf, '\0', sizeof(outbuf));
 142         construct_reply_common((char *)request_buf, outbuf);
 143
 144         ERROR_NT(error_code);
 145
 146         /*
 147          * Seems NT needs a transact command with an error code
 148          * in it. This is a longer packet than a simple error.
 149          */
 150         srv_set_message(outbuf,18,0,False);
 151
 152         show_msg(outbuf);
 153         if (!srv_send_smb(smbd_server_fd(),
 154                         outbuf,
 155                         IS_CONN_ENCRYPTED(conn)))
 156                 exit_server_cleanly("change_notify_reply_packet: srv_send_smb "
 157                                     "failed.");
 158 }
 159
 160 void change_notify_reply(connection_struct *conn,
 161                         const uint8 *request_buf, uint32 max_param,
 162                          struct notify_change_buf *notify_buf)
 163 {
 164         prs_struct ps;
 165         struct smb_request *req = NULL;
 166         uint8 tmp_request[smb_size];
 167
 168         if (notify_buf->num_changes == -1) {
 169                 change_notify_reply_packet(conn, request_buf, NT_STATUS_OK);
 170                 notify_buf->num_changes = 0;
 171                 return;
 172         }
 173
 174         prs_init_empty(&ps, NULL, MARSHALL);
 175
 176         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 177                                         notify_buf->changes, &ps)) {
 178                 /*
 179                  * We exceed what the client is willing to accept. Send
 180                  * nothing.
 181                  */
 182                 change_notify_reply_packet(conn, request_buf, NT_STATUS_OK);
 183                 goto done;
 184         }
 185
 186         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 187                 change_notify_reply_packet(conn, request_buf, NT_STATUS_NO_MEMORY);
 188                 goto done;
 189         }
 190
 191         memcpy(tmp_request, request_buf, smb_size);
 192
 193         /*
 194          * We're only interested in the header fields here
 195          */
 196
 197         smb_setlen((char *)tmp_request, smb_size);
 198         SCVAL(tmp_request, smb_wct, 0);
 199
 200         init_smb_request(req, tmp_request,0, conn->encrypted_tid);
 201
 202         send_nt_replies(conn, req, NT_STATUS_OK, prs_data_p(&ps),
 203                         prs_offset(&ps), NULL, 0);
 204
 205  done:
 206         TALLOC_FREE(req);
 207         prs_mem_free(&ps);
 208
 209         TALLOC_FREE(notify_buf->changes);
 210         notify_buf->num_changes = 0;
 211 }
 212
 213 static void notify_callback(void *private_data, const struct notify_event *e)
 214 {
 215         files_struct *fsp = (files_struct *)private_data;
 216         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 217         notify_fsp(fsp, e->action, e->path);
 218 }
 219
 220 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 221                               bool recursive)
 222 {
 223         char *fullpath;
 224         struct notify_entry e;
 225         NTSTATUS status;
 226
 227         SMB_ASSERT(fsp->notify == NULL);
 228
 229         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 230                 DEBUG(0, ("talloc failed\n"));
 231                 return NT_STATUS_NO_MEMORY;
 232         }
 233
 234         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 235                      fsp->fsp_name) == -1) {
 236                 DEBUG(0, ("asprintf failed\n"));
 237                 TALLOC_FREE(fsp->notify);
 238                 return NT_STATUS_NO_MEMORY;
 239         }
 240
 241         ZERO_STRUCT(e);
 242         e.path = fullpath;
 243         e.filter = filter;
 244         e.subdir_filter = 0;
 245         if (recursive) {
 246                 e.subdir_filter = filter;
 247         }
 248
 249         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 250         SAFE_FREE(fullpath);
 251
 252         return status;
 253 }
 254
 255 NTSTATUS change_notify_add_request(const struct smb_request *req,
 256                                 uint32 max_param,
 257                                 uint32 filter, bool recursive,
 258                                 struct files_struct *fsp)
 259 {
 260         struct notify_change_request *request = NULL;
 261         struct notify_mid_map *map = NULL;
 262
 263         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 264                    "max_param = %d\n", fsp->fsp_name, (int)max_param));
 265
 266         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 267             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 268                 SAFE_FREE(request);
 269                 return NT_STATUS_NO_MEMORY;
 270         }
 271
 272         request->mid_map = map;
 273         map->req = request;
 274
 275         memcpy(request->request_buf, req->inbuf, sizeof(request->request_buf));
 276         request->max_param = max_param;
 277         request->filter = filter;
 278         request->fsp = fsp;
 279         request->backend_data = NULL;
 280
 281         DLIST_ADD_END(fsp->notify->requests, request,
 282                       struct notify_change_request *);
 283
 284         map->mid = SVAL(req->inbuf, smb_mid);
 285         DLIST_ADD(notify_changes_by_mid, map);
 286
 287         /* Push the MID of this packet on the signing queue. */
 288         srv_defer_sign_response(SVAL(req->inbuf,smb_mid));
 289
 290         return NT_STATUS_OK;
 291 }
 292
 293 static void change_notify_remove_request(struct notify_change_request *remove_req)
 294 {
 295         files_struct *fsp;
 296         struct notify_change_request *req;
 297
 298         /*
 299          * Paranoia checks, the fsp referenced must must have the request in
 300          * its list of pending requests
 301          */
 302
 303         fsp = remove_req->fsp;
 304         SMB_ASSERT(fsp->notify != NULL);
 305
 306         for (req = fsp->notify->requests; req; req = req->next) {
 307                 if (req == remove_req) {
 308                         break;
 309                 }
 310         }
 311
 312         if (req == NULL) {
 313                 smb_panic("notify_req not found in fsp's requests");
 314         }
 315
 316         DLIST_REMOVE(fsp->notify->requests, req);
 317         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 318         SAFE_FREE(req->mid_map);
 319         TALLOC_FREE(req->backend_data);
 320         SAFE_FREE(req);
 321 }
 322
 323 /****************************************************************************
 324  Delete entries by mid from the change notify pending queue. Always send reply.
 325 *****************************************************************************/
 326
 327 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 328 {
 329         struct notify_mid_map *map;
 330
 331         for (map = notify_changes_by_mid; map; map = map->next) {
 332                 if (map->mid == mid) {
 333                         break;
 334                 }
 335         }
 336
 337         if (map == NULL) {
 338                 return;
 339         }
 340
 341         change_notify_reply_packet(map->req->fsp->conn,
 342                         map->req->request_buf, NT_STATUS_CANCELLED);
 343         change_notify_remove_request(map->req);
 344 }
 345
 346 /****************************************************************************
 347  Delete entries by fnum from the change notify pending queue.
 348 *****************************************************************************/
 349
 350 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 351                                                   NTSTATUS status)
 352 {
 353         if (fsp->notify == NULL) {
 354                 return;
 355         }
 356
 357         while (fsp->notify->requests != NULL) {
 358                 change_notify_reply_packet(fsp->conn,
 359                         fsp->notify->requests->request_buf, status);
 360                 change_notify_remove_request(fsp->notify->requests);
 361         }
 362 }
 363
 364 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 365                   const char *path)
 366 {
 367         char *fullpath;
 368
 369         if (path[0] == '.' && path[1] == '/') {
 370                 path += 2;
 371         }
 372         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 373                 DEBUG(0, ("asprintf failed\n"));
 374                 return;
 375         }
 376
 377         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 378         SAFE_FREE(fullpath);
 379 }
 380
 381 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 382 {
 383         struct notify_change *change, *changes;
 384         char *tmp;
 385
 386         if (fsp->notify == NULL) {
 387                 /*
 388                  * Nobody is waiting, don't queue
 389                  */
 390                 return;
 391         }
 392
 393         /*
 394          * Someone has triggered a notify previously, queue the change for
 395          * later.
 396          */
 397
 398         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 399                 /*
 400                  * The real number depends on the client buf, just provide a
 401                  * guard against a DoS here.
 402                  */
 403                 TALLOC_FREE(fsp->notify->changes);
 404                 fsp->notify->num_changes = -1;
 405                 return;
 406         }
 407
 408         if (fsp->notify->num_changes == -1) {
 409                 return;
 410         }
 411
 412         if (!(changes = TALLOC_REALLOC_ARRAY(
 413                       fsp->notify, fsp->notify->changes,
 414                       struct notify_change, fsp->notify->num_changes+1))) {
 415                 DEBUG(0, ("talloc_realloc failed\n"));
 416                 return;
 417         }
 418
 419         fsp->notify->changes = changes;
 420
 421         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 422
 423         if (!(tmp = talloc_strdup(changes, name))) {
 424                 DEBUG(0, ("talloc_strdup failed\n"));
 425                 return;
 426         }
 427
 428         string_replace(tmp, '/', '\\');
 429         change->name = tmp;
 430
 431         change->action = action;
 432         fsp->notify->num_changes += 1;
 433
 434         if (fsp->notify->requests == NULL) {
 435                 /*
 436                  * Nobody is waiting, so don't send anything. The ot
 437                  */
 438                 return;
 439         }
 440
 441         if (action == NOTIFY_ACTION_OLD_NAME) {
 442                 /*
 443                  * We have to send the two rename events in one reply. So hold
 444                  * the first part back.
 445                  */
 446                 return;
 447         }
 448
 449         /*
 450          * Someone is waiting for the change, trigger the reply immediately.
 451          *
 452          * TODO: do we have to walk the lists of requests pending?
 453          */
 454
 455         change_notify_reply(fsp->conn,
 456                         fsp->notify->requests->request_buf,
 457                             fsp->notify->requests->max_param,
 458                             fsp->notify);
 459
 460         change_notify_remove_request(fsp->notify->requests);
 461 }
 462
 463 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 464 {
 465         char *result = NULL;
 466
 467         result = talloc_strdup(mem_ctx, "");
 468
 469         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 470                 result = talloc_asprintf_append(result, "FILE_NAME|");
 471         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 472                 result = talloc_asprintf_append(result, "DIR_NAME|");
 473         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 474                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 475         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 476                 result = talloc_asprintf_append(result, "SIZE|");
 477         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 478                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 479         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 480                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 481         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 482                 result = talloc_asprintf_append(result, "CREATION|");
 483         if (filter & FILE_NOTIFY_CHANGE_EA)
 484                 result = talloc_asprintf_append(result, "EA|");
 485         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 486                 result = talloc_asprintf_append(result, "SECURITY|");
 487         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 488                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 489         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 490                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 491         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 492                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 493
 494         if (result == NULL) return NULL;
 495         if (*result == '\0') return result;
 496
 497         result[strlen(result)-1] = '\0';
 498         return result;
 499 }
 500
 501 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 502                                                      TALLOC_CTX *mem_ctx,
 503                                                      struct event_context *ev)
 504 {
 505         struct sys_notify_context *ctx;
 506
 507         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 508                 DEBUG(0, ("talloc failed\n"));
 509                 return NULL;
 510         }
 511
 512         ctx->ev = ev;
 513         ctx->conn = conn;
 514         ctx->private_data = NULL;
 515         return ctx;
 516 }
 517
 518 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 519                           struct notify_entry *e,
 520                           void (*callback)(struct sys_notify_context *ctx,
 521                                            void *private_data,
 522                                            struct notify_event *ev),
 523                           void *private_data, void *handle)
 524 {
 525         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 526                                     handle);
 527 }
 528