source3/lib/wbclient.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Infrastructure for async winbind requests
   4    Copyright (C) Volker Lendecke 2008
   5
   6      ** NOTE! The following LGPL license applies to the wbclient
   7      ** library. This does NOT imply that all of Samba is released
   8      ** under the LGPL
   9
  10    This library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Lesser General Public
  12    License as published by the Free Software Foundation; either
  13    version 3 of the License, or (at your option) any later version.
  14
  15    This library is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Library General Public License for more details.
  19
  20    You should have received a copy of the GNU Lesser General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "wbc_async.h"
  26
  27 wbcErr map_wbc_err_from_errno(int error)
  28 {
  29         switch(error) {
  30         case EPERM:
  31         case EACCES:
  32                 return WBC_ERR_AUTH_ERROR;
  33         case ENOMEM:
  34                 return WBC_ERR_NO_MEMORY;
  35         case EIO:
  36         default:
  37                 return WBC_ERR_UNKNOWN_FAILURE;
  38         }
  39 }
  40
  41 bool tevent_req_is_wbcerr(struct tevent_req *req, wbcErr *pwbc_err)
  42 {
  43         enum tevent_req_state state;
  44         uint64_t error;
  45         if (!tevent_req_is_error(req, &state, &error)) {
  46                 *pwbc_err = WBC_ERR_SUCCESS;
  47                 return false;
  48         }
  49
  50         switch (state) {
  51         case TEVENT_REQ_USER_ERROR:
  52                 *pwbc_err = error;
  53                 break;
  54         case TEVENT_REQ_TIMED_OUT:
  55                 *pwbc_err = WBC_ERR_UNKNOWN_FAILURE;
  56                 break;
  57         case TEVENT_REQ_NO_MEMORY:
  58                 *pwbc_err = WBC_ERR_NO_MEMORY;
  59                 break;
  60         default:
  61                 *pwbc_err = WBC_ERR_UNKNOWN_FAILURE;
  62                 break;
  63         }
  64         return true;
  65 }
  66
  67 wbcErr tevent_req_simple_recv_wbcerr(struct tevent_req *req)
  68 {
  69         wbcErr wbc_err;
  70
  71         if (tevent_req_is_wbcerr(req, &wbc_err)) {
  72                 return wbc_err;
  73         }
  74
  75         return WBC_ERR_SUCCESS;
  76 }
  77
  78 struct wb_context {
  79         struct tevent_queue *queue;
  80         int fd;
  81         bool is_priv;
  82 };
  83
  84 static int make_nonstd_fd(int fd)
  85 {
  86         int i;
  87         int sys_errno = 0;
  88         int fds[3];
  89         int num_fds = 0;
  90
  91         if (fd == -1) {
  92                 return -1;
  93         }
  94         while (fd < 3) {
  95                 fds[num_fds++] = fd;
  96                 fd = dup(fd);
  97                 if (fd == -1) {
  98                         sys_errno = errno;
  99                         break;
 100                 }
 101         }
 102         for (i=0; i<num_fds; i++) {
 103                 close(fds[i]);
 104         }
 105         if (fd == -1) {
 106                 errno = sys_errno;
 107         }
 108         return fd;
 109 }
 110
 111 /****************************************************************************
 112  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 113  else
 114  if SYSV use O_NDELAY
 115  if BSD use FNDELAY
 116  Set close on exec also.
 117 ****************************************************************************/
 118
 119 static int make_safe_fd(int fd)
 120 {
 121         int result, flags;
 122         int new_fd = make_nonstd_fd(fd);
 123
 124         if (new_fd == -1) {
 125                 goto fail;
 126         }
 127
 128         /* Socket should be nonblocking. */
 129
 130 #ifdef O_NONBLOCK
 131 #define FLAG_TO_SET O_NONBLOCK
 132 #else
 133 #ifdef SYSV
 134 #define FLAG_TO_SET O_NDELAY
 135 #else /* BSD */
 136 #define FLAG_TO_SET FNDELAY
 137 #endif
 138 #endif
 139
 140         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 141                 goto fail;
 142         }
 143
 144         flags |= FLAG_TO_SET;
 145         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 146                 goto fail;
 147         }
 148
 149 #undef FLAG_TO_SET
 150
 151         /* Socket should be closed on exec() */
 152 #ifdef FD_CLOEXEC
 153         result = flags = fcntl(new_fd, F_GETFD, 0);
 154         if (flags >= 0) {
 155                 flags |= FD_CLOEXEC;
 156                 result = fcntl( new_fd, F_SETFD, flags );
 157         }
 158         if (result < 0) {
 159                 goto fail;
 160         }
 161 #endif
 162         return new_fd;
 163
 164  fail:
 165         if (new_fd != -1) {
 166                 int sys_errno = errno;
 167                 close(new_fd);
 168                 errno = sys_errno;
 169         }
 170         return -1;
 171 }
 172
 173 struct wb_context *wb_context_init(TALLOC_CTX *mem_ctx)
 174 {
 175         struct wb_context *result;
 176
 177         result = talloc(mem_ctx, struct wb_context);
 178         if (result == NULL) {
 179                 return NULL;
 180         }
 181         result->queue = tevent_queue_create(result, "wb_trans");
 182         if (result->queue == NULL) {
 183                 TALLOC_FREE(result);
 184                 return NULL;
 185         }
 186         result->fd = -1;
 187         result->is_priv = false;
 188         return result;
 189 }
 190
 191 struct wb_connect_state {
 192         int dummy;
 193 };
 194
 195 static void wbc_connect_connected(struct tevent_req *subreq);
 196
 197 static struct tevent_req *wb_connect_send(TALLOC_CTX *mem_ctx,
 198                                           struct tevent_context *ev,
 199                                           struct wb_context *wb_ctx,
 200                                           const char *dir)
 201 {
 202         struct tevent_req *result, *subreq;
 203         struct wb_connect_state *state;
 204         struct sockaddr_un sunaddr;
 205         struct stat st;
 206         char *path = NULL;
 207         wbcErr wbc_err;
 208
 209         result = tevent_req_create(mem_ctx, &state, struct wb_connect_state);
 210         if (result == NULL) {
 211                 return NULL;
 212         }
 213
 214         if (wb_ctx->fd != -1) {
 215                 close(wb_ctx->fd);
 216                 wb_ctx->fd = -1;
 217         }
 218
 219         /* Check permissions on unix socket directory */
 220
 221         if (lstat(dir, &st) == -1) {
 222                 wbc_err = WBC_ERR_WINBIND_NOT_AVAILABLE;
 223                 goto post_status;
 224         }
 225
 226         if (!S_ISDIR(st.st_mode) ||
 227             (st.st_uid != 0 && st.st_uid != geteuid())) {
 228                 wbc_err = WBC_ERR_WINBIND_NOT_AVAILABLE;
 229                 goto post_status;
 230         }
 231
 232         /* Connect to socket */
 233
 234         path = talloc_asprintf(talloc_tos(), "%s/%s", dir,
 235                                WINBINDD_SOCKET_NAME);
 236         if (path == NULL) {
 237                 goto nomem;
 238         }
 239
 240         sunaddr.sun_family = AF_UNIX;
 241         strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path));
 242         TALLOC_FREE(path);
 243
 244         /* If socket file doesn't exist, don't bother trying to connect
 245            with retry.  This is an attempt to make the system usable when
 246            the winbindd daemon is not running. */
 247
 248         if ((lstat(sunaddr.sun_path, &st) == -1)
 249             || !S_ISSOCK(st.st_mode)
 250             || (st.st_uid != 0 && st.st_uid != geteuid())) {
 251                 wbc_err = WBC_ERR_WINBIND_NOT_AVAILABLE;
 252                 goto post_status;
 253         }
 254
 255         wb_ctx->fd = make_safe_fd(socket(AF_UNIX, SOCK_STREAM, 0));
 256         if (wb_ctx->fd == -1) {
 257                 wbc_err = map_wbc_err_from_errno(errno);
 258                 goto post_status;
 259         }
 260
 261         subreq = async_connect_send(mem_ctx, ev, wb_ctx->fd,
 262                                     (struct sockaddr *)(void *)&sunaddr,
 263                                     sizeof(sunaddr));
 264         if (subreq == NULL) {
 265                 goto nomem;
 266         }
 267         tevent_req_set_callback(subreq, wbc_connect_connected, result);
 268         return result;
 269
 270  post_status:
 271         tevent_req_error(result, wbc_err);
 272         return tevent_req_post(result, ev);
 273  nomem:
 274         TALLOC_FREE(result);
 275         return NULL;
 276 }
 277
 278 static void wbc_connect_connected(struct tevent_req *subreq)
 279 {
 280         struct tevent_req *req = tevent_req_callback_data(
 281                 subreq, struct tevent_req);
 282         int res, err;
 283
 284         res = async_connect_recv(subreq, &err);
 285         TALLOC_FREE(subreq);
 286         if (res == -1) {
 287                 tevent_req_error(req, map_wbc_err_from_errno(err));
 288                 return;
 289         }
 290         tevent_req_done(req);
 291 }
 292
 293 static wbcErr wb_connect_recv(struct tevent_req *req)
 294 {
 295         return tevent_req_simple_recv_wbcerr(req);
 296 }
 297
 298 static const char *winbindd_socket_dir(void)
 299 {
 300 #ifdef SOCKET_WRAPPER
 301         const char *env_dir;
 302
 303         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 304         if (env_dir) {
 305                 return env_dir;
 306         }
 307 #endif
 308
 309         return WINBINDD_SOCKET_DIR;
 310 }
 311
 312 struct wb_open_pipe_state {
 313         struct wb_context *wb_ctx;
 314         struct tevent_context *ev;
 315         bool need_priv;
 316         struct winbindd_request wb_req;
 317 };
 318
 319 static void wb_open_pipe_connect_nonpriv_done(struct tevent_req *subreq);
 320 static void wb_open_pipe_ping_done(struct tevent_req *subreq);
 321 static void wb_open_pipe_getpriv_done(struct tevent_req *subreq);
 322 static void wb_open_pipe_connect_priv_done(struct tevent_req *subreq);
 323
 324 static struct tevent_req *wb_open_pipe_send(TALLOC_CTX *mem_ctx,
 325                                             struct tevent_context *ev,
 326                                             struct wb_context *wb_ctx,
 327                                             bool need_priv)
 328 {
 329         struct tevent_req *result, *subreq;
 330         struct wb_open_pipe_state *state;
 331
 332         result = tevent_req_create(mem_ctx, &state, struct wb_open_pipe_state);
 333         if (result == NULL) {
 334                 return NULL;
 335         }
 336         state->wb_ctx = wb_ctx;
 337         state->ev = ev;
 338         state->need_priv = need_priv;
 339
 340         if (wb_ctx->fd != -1) {
 341                 close(wb_ctx->fd);
 342                 wb_ctx->fd = -1;
 343         }
 344
 345         subreq = wb_connect_send(state, ev, wb_ctx, winbindd_socket_dir());
 346         if (subreq == NULL) {
 347                 goto fail;
 348         }
 349         tevent_req_set_callback(subreq, wb_open_pipe_connect_nonpriv_done,
 350                                 result);
 351         return result;
 352
 353  fail:
 354         TALLOC_FREE(result);
 355         return NULL;
 356 }
 357
 358 static void wb_open_pipe_connect_nonpriv_done(struct tevent_req *subreq)
 359 {
 360         struct tevent_req *req = tevent_req_callback_data(
 361                 subreq, struct tevent_req);
 362         struct wb_open_pipe_state *state = tevent_req_data(
 363                 req, struct wb_open_pipe_state);
 364         wbcErr wbc_err;
 365
 366         wbc_err = wb_connect_recv(subreq);
 367         TALLOC_FREE(subreq);
 368         if (!WBC_ERROR_IS_OK(wbc_err)) {
 369                 state->wb_ctx->is_priv = true;
 370                 tevent_req_error(req, wbc_err);
 371                 return;
 372         }
 373
 374         ZERO_STRUCT(state->wb_req);
 375         state->wb_req.cmd = WINBINDD_INTERFACE_VERSION;
 376         state->wb_req.pid = getpid();
 377
 378         subreq = wb_simple_trans_send(state, state->ev, NULL,
 379                                       state->wb_ctx->fd, &state->wb_req);
 380         if (tevent_req_nomem(subreq, req)) {
 381                 return;
 382         }
 383         tevent_req_set_callback(subreq, wb_open_pipe_ping_done, req);
 384 }
 385
 386 static void wb_open_pipe_ping_done(struct tevent_req *subreq)
 387 {
 388         struct tevent_req *req = tevent_req_callback_data(
 389                 subreq, struct tevent_req);
 390         struct wb_open_pipe_state *state = tevent_req_data(
 391                 req, struct wb_open_pipe_state);
 392         struct winbindd_response *wb_resp;
 393         int ret, err;
 394
 395         ret = wb_simple_trans_recv(subreq, state, &wb_resp, &err);
 396         TALLOC_FREE(subreq);
 397         if (ret == -1) {
 398                 tevent_req_error(req, map_wbc_err_from_errno(err));
 399                 return;
 400         }
 401
 402         if (!state->need_priv) {
 403                 tevent_req_done(req);
 404                 return;
 405         }
 406
 407         state->wb_req.cmd = WINBINDD_PRIV_PIPE_DIR;
 408         state->wb_req.pid = getpid();
 409
 410         subreq = wb_simple_trans_send(state, state->ev, NULL,
 411                                       state->wb_ctx->fd, &state->wb_req);
 412         if (tevent_req_nomem(subreq, req)) {
 413                 return;
 414         }
 415         tevent_req_set_callback(subreq, wb_open_pipe_getpriv_done, req);
 416 }
 417
 418 static void wb_open_pipe_getpriv_done(struct tevent_req *subreq)
 419 {
 420         struct tevent_req *req = tevent_req_callback_data(
 421                 subreq, struct tevent_req);
 422         struct wb_open_pipe_state *state = tevent_req_data(
 423                 req, struct wb_open_pipe_state);
 424         struct winbindd_response *wb_resp = NULL;
 425         int ret, err;
 426
 427         ret = wb_simple_trans_recv(subreq, state, &wb_resp, &err);
 428         TALLOC_FREE(subreq);
 429         if (ret == -1) {
 430                 tevent_req_error(req, map_wbc_err_from_errno(err));
 431                 return;
 432         }
 433
 434         close(state->wb_ctx->fd);
 435         state->wb_ctx->fd = -1;
 436
 437         subreq = wb_connect_send(state, state->ev, state->wb_ctx,
 438                                   (char *)wb_resp->extra_data.data);
 439         TALLOC_FREE(wb_resp);
 440         if (tevent_req_nomem(subreq, req)) {
 441                 return;
 442         }
 443         tevent_req_set_callback(subreq, wb_open_pipe_connect_priv_done, req);
 444 }
 445
 446 static void wb_open_pipe_connect_priv_done(struct tevent_req *subreq)
 447 {
 448         struct tevent_req *req = tevent_req_callback_data(
 449                 subreq, struct tevent_req);
 450         struct wb_open_pipe_state *state = tevent_req_data(
 451                 req, struct wb_open_pipe_state);
 452         wbcErr wbc_err;
 453
 454         wbc_err = wb_connect_recv(subreq);
 455         TALLOC_FREE(subreq);
 456         if (!WBC_ERROR_IS_OK(wbc_err)) {
 457                 tevent_req_error(req, wbc_err);
 458                 return;
 459         }
 460         state->wb_ctx->is_priv = true;
 461         tevent_req_done(req);
 462 }
 463
 464 static wbcErr wb_open_pipe_recv(struct tevent_req *req)
 465 {
 466         return tevent_req_simple_recv_wbcerr(req);
 467 }
 468
 469 struct wb_trans_state {
 470         struct wb_trans_state *prev, *next;
 471         struct wb_context *wb_ctx;
 472         struct tevent_context *ev;
 473         struct winbindd_request *wb_req;
 474         struct winbindd_response *wb_resp;
 475         bool need_priv;
 476 };
 477
 478 static bool closed_fd(int fd)
 479 {
 480         struct timeval tv;
 481         fd_set r_fds;
 482         int selret;
 483
 484         if (fd == -1) {
 485                 return true;
 486         }
 487
 488         FD_ZERO(&r_fds);
 489         FD_SET(fd, &r_fds);
 490         ZERO_STRUCT(tv);
 491
 492         selret = select(fd+1, &r_fds, NULL, NULL, &tv);
 493         if (selret == -1) {
 494                 return true;
 495         }
 496         if (selret == 0) {
 497                 return false;
 498         }
 499         return (FD_ISSET(fd, &r_fds));
 500 }
 501
 502 static void wb_trans_trigger(struct tevent_req *req, void *private_data);
 503 static void wb_trans_connect_done(struct tevent_req *subreq);
 504 static void wb_trans_done(struct tevent_req *subreq);
 505 static void wb_trans_retry_wait_done(struct tevent_req *subreq);
 506
 507 struct tevent_req *wb_trans_send(TALLOC_CTX *mem_ctx,
 508                                  struct tevent_context *ev,
 509                                  struct wb_context *wb_ctx, bool need_priv,
 510                                  struct winbindd_request *wb_req)
 511 {
 512         struct tevent_req *req;
 513         struct wb_trans_state *state;
 514
 515         req = tevent_req_create(mem_ctx, &state, struct wb_trans_state);
 516         if (req == NULL) {
 517                 return NULL;
 518         }
 519         state->wb_ctx = wb_ctx;
 520         state->ev = ev;
 521         state->wb_req = wb_req;
 522         state->need_priv = need_priv;
 523
 524         if (!tevent_queue_add(wb_ctx->queue, ev, req, wb_trans_trigger,
 525                               NULL)) {
 526                 tevent_req_nomem(NULL, req);
 527                 return tevent_req_post(req, ev);
 528         }
 529         return req;
 530 }
 531
 532 static void wb_trans_trigger(struct tevent_req *req, void *private_data)
 533 {
 534         struct wb_trans_state *state = tevent_req_data(
 535                 req, struct wb_trans_state);
 536         struct tevent_req *subreq;
 537
 538         if ((state->wb_ctx->fd != -1) && closed_fd(state->wb_ctx->fd)) {
 539                 close(state->wb_ctx->fd);
 540                 state->wb_ctx->fd = -1;
 541         }
 542
 543         if ((state->wb_ctx->fd == -1)
 544             || (state->need_priv && !state->wb_ctx->is_priv)) {
 545                 subreq = wb_open_pipe_send(state, state->ev, state->wb_ctx,
 546                                            state->need_priv);
 547                 if (tevent_req_nomem(subreq, req)) {
 548                         return;
 549                 }
 550                 tevent_req_set_callback(subreq, wb_trans_connect_done, req);
 551                 return;
 552         }
 553
 554         state->wb_req->pid = getpid();
 555
 556         subreq = wb_simple_trans_send(state, state->ev, NULL,
 557                                       state->wb_ctx->fd, state->wb_req);
 558         if (tevent_req_nomem(subreq, req)) {
 559                 return;
 560         }
 561         tevent_req_set_callback(subreq, wb_trans_done, req);
 562 }
 563
 564 static bool wb_trans_retry(struct tevent_req *req,
 565                            struct wb_trans_state *state,
 566                            wbcErr wbc_err)
 567 {
 568         struct tevent_req *subreq;
 569
 570         if (WBC_ERROR_IS_OK(wbc_err)) {
 571                 return false;
 572         }
 573
 574         if (wbc_err == WBC_ERR_WINBIND_NOT_AVAILABLE) {
 575                 /*
 576                  * Winbind not around or we can't connect to the pipe. Fail
 577                  * immediately.
 578                  */
 579                 tevent_req_error(req, wbc_err);
 580                 return true;
 581         }
 582
 583         /*
 584          * The transfer as such failed, retry after one second
 585          */
 586
 587         if (state->wb_ctx->fd != -1) {
 588                 close(state->wb_ctx->fd);
 589                 state->wb_ctx->fd = -1;
 590         }
 591
 592         subreq = tevent_wakeup_send(state, state->ev,
 593                                     timeval_current_ofs(1, 0));
 594         if (tevent_req_nomem(subreq, req)) {
 595                 return true;
 596         }
 597         tevent_req_set_callback(subreq, wb_trans_retry_wait_done, req);
 598         return true;
 599 }
 600
 601 static void wb_trans_retry_wait_done(struct tevent_req *subreq)
 602 {
 603         struct tevent_req *req = tevent_req_callback_data(
 604                 subreq, struct tevent_req);
 605         struct wb_trans_state *state = tevent_req_data(
 606                 req, struct wb_trans_state);
 607         bool ret;
 608
 609         ret = tevent_wakeup_recv(subreq);
 610         TALLOC_FREE(subreq);
 611         if (!ret) {
 612                 tevent_req_error(req, WBC_ERR_UNKNOWN_FAILURE);
 613                 return;
 614         }
 615
 616         subreq = wb_open_pipe_send(state, state->ev, state->wb_ctx,
 617                                    state->need_priv);
 618         if (tevent_req_nomem(subreq, req)) {
 619                 return;
 620         }
 621         tevent_req_set_callback(subreq, wb_trans_connect_done, req);
 622 }
 623
 624 static void wb_trans_connect_done(struct tevent_req *subreq)
 625 {
 626         struct tevent_req *req = tevent_req_callback_data(
 627                 subreq, struct tevent_req);
 628         struct wb_trans_state *state = tevent_req_data(
 629                 req, struct wb_trans_state);
 630         wbcErr wbc_err;
 631
 632         wbc_err = wb_open_pipe_recv(subreq);
 633         TALLOC_FREE(subreq);
 634
 635         if (wb_trans_retry(req, state, wbc_err)) {
 636                 return;
 637         }
 638
 639         subreq = wb_simple_trans_send(state, state->ev, NULL,
 640                                       state->wb_ctx->fd, state->wb_req);
 641         if (tevent_req_nomem(subreq, req)) {
 642                 return;
 643         }
 644         tevent_req_set_callback(subreq, wb_trans_done, req);
 645 }
 646
 647 static void wb_trans_done(struct tevent_req *subreq)
 648 {
 649         struct tevent_req *req = tevent_req_callback_data(
 650                 subreq, struct tevent_req);
 651         struct wb_trans_state *state = tevent_req_data(
 652                 req, struct wb_trans_state);
 653         int ret, err;
 654
 655         ret = wb_simple_trans_recv(subreq, state, &state->wb_resp, &err);
 656         TALLOC_FREE(subreq);
 657         if ((ret == -1)
 658             && wb_trans_retry(req, state, map_wbc_err_from_errno(err))) {
 659                 return;
 660         }
 661
 662         tevent_req_done(req);
 663 }
 664
 665 wbcErr wb_trans_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 666                      struct winbindd_response **presponse)
 667 {
 668         struct wb_trans_state *state = tevent_req_data(
 669                 req, struct wb_trans_state);
 670         wbcErr wbc_err;
 671
 672         if (tevent_req_is_wbcerr(req, &wbc_err)) {
 673                 return wbc_err;
 674         }
 675
 676         *presponse = talloc_move(mem_ctx, &state->wb_resp);
 677         return WBC_ERR_SUCCESS;
 678 }