source3/lib/wbclient.c

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