nsswitch/libwbclient/wbc_async.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 "replace.h"
  25 #include "system/filesys.h"
  26 #include "system/network.h"
  27 #include <talloc.h>
  28 #include <tevent.h>
  29 struct fd_event;
  30 struct event_context;
  31 #include "lib/async_req/async_sock.h"
  32 #include "nsswitch/winbind_struct_protocol.h"
  33 #include "nsswitch/libwbclient/wbclient.h"
  34 #include "nsswitch/libwbclient/wbc_async.h"
  35
  36 wbcErr map_wbc_err_from_errno(int error)
  37 {
  38         switch(error) {
  39         case EPERM:
  40         case EACCES:
  41                 return WBC_ERR_AUTH_ERROR;
  42         case ENOMEM:
  43                 return WBC_ERR_NO_MEMORY;
  44         case EIO:
  45         default:
  46                 return WBC_ERR_UNKNOWN_FAILURE;
  47         }
  48 }
  49
  50 bool tevent_req_is_wbcerr(struct tevent_req *req, wbcErr *pwbc_err)
  51 {
  52         enum tevent_req_state state;
  53         uint64_t error;
  54         if (!tevent_req_is_error(req, &state, &error)) {
  55                 *pwbc_err = WBC_ERR_SUCCESS;
  56                 return false;
  57         }
  58
  59         switch (state) {
  60         case TEVENT_REQ_USER_ERROR:
  61                 *pwbc_err = error;
  62                 break;
  63         case TEVENT_REQ_TIMED_OUT:
  64                 *pwbc_err = WBC_ERR_UNKNOWN_FAILURE;
  65                 break;
  66         case TEVENT_REQ_NO_MEMORY:
  67                 *pwbc_err = WBC_ERR_NO_MEMORY;
  68                 break;
  69         default:
  70                 *pwbc_err = WBC_ERR_UNKNOWN_FAILURE;
  71                 break;
  72         }
  73         return true;
  74 }
  75
  76 wbcErr tevent_req_simple_recv_wbcerr(struct tevent_req *req)
  77 {
  78         wbcErr wbc_err;
  79
  80         if (tevent_req_is_wbcerr(req, &wbc_err)) {
  81                 return wbc_err;
  82         }
  83
  84         return WBC_ERR_SUCCESS;
  85 }
  86
  87 struct wb_context {
  88         struct tevent_queue *queue;
  89         int fd;
  90         bool is_priv;
  91 };
  92
  93 static int make_nonstd_fd(int fd)
  94 {
  95         int i;
  96         int sys_errno = 0;
  97         int fds[3];
  98         int num_fds = 0;
  99
 100         if (fd == -1) {
 101                 return -1;
 102         }
 103         while (fd < 3) {
 104                 fds[num_fds++] = fd;
 105                 fd = dup(fd);
 106                 if (fd == -1) {
 107                         sys_errno = errno;
 108                         break;
 109                 }
 110         }
 111         for (i=0; i<num_fds; i++) {
 112                 close(fds[i]);
 113         }
 114         if (fd == -1) {
 115                 errno = sys_errno;
 116         }
 117         return fd;
 118 }
 119
 120 /****************************************************************************
 121  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 122  else
 123  if SYSV use O_NDELAY
 124  if BSD use FNDELAY
 125  Set close on exec also.
 126 ****************************************************************************/
 127
 128 static int make_safe_fd(int fd)
 129 {
 130         int result, flags;
 131         int new_fd = make_nonstd_fd(fd);
 132
 133         if (new_fd == -1) {
 134                 goto fail;
 135         }
 136
 137         /* Socket should be nonblocking. */
 138
 139 #ifdef O_NONBLOCK
 140 #define FLAG_TO_SET O_NONBLOCK
 141 #else
 142 #ifdef SYSV
 143 #define FLAG_TO_SET O_NDELAY
 144 #else /* BSD */
 145 #define FLAG_TO_SET FNDELAY
 146 #endif
 147 #endif
 148
 149         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 150                 goto fail;
 151         }
 152
 153         flags |= FLAG_TO_SET;
 154         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 155                 goto fail;
 156         }
 157
 158 #undef FLAG_TO_SET
 159
 160         /* Socket should be closed on exec() */
 161 #ifdef FD_CLOEXEC
 162         result = flags = fcntl(new_fd, F_GETFD, 0);
 163         if (flags >= 0) {
 164                 flags |= FD_CLOEXEC;
 165                 result = fcntl( new_fd, F_SETFD, flags );
 166         }
 167         if (result < 0) {
 168                 goto fail;
 169         }
 170 #endif
 171         return new_fd;
 172
 173  fail:
 174         if (new_fd != -1) {
 175                 int sys_errno = errno;
 176                 close(new_fd);
 177                 errno = sys_errno;
 178         }
 179         return -1;
 180 }
 181
 182 struct wb_context *wb_context_init(TALLOC_CTX *mem_ctx)
 183 {
 184         struct wb_context *result;
 185
 186         result = talloc(mem_ctx, struct wb_context);
 187         if (result == NULL) {
 188                 return NULL;
 189         }
 190         result->queue = tevent_queue_create(result, "wb_trans");
 191         if (result->queue == NULL) {
 192                 TALLOC_FREE(result);
 193                 return NULL;
 194         }
 195         result->fd = -1;
 196         result->is_priv = false;
 197         return result;
 198 }
 199
 200 struct wb_connect_state {
 201         int dummy;
 202 };
 203
 204 static void wbc_connect_connected(struct tevent_req *subreq);
 205
 206 static struct tevent_req *wb_connect_send(TALLOC_CTX *mem_ctx,
 207                                           struct tevent_context *ev,
 208                                           struct wb_context *wb_ctx,
 209                                           const char *dir)
 210 {
 211         struct tevent_req *result, *subreq;
 212         struct wb_connect_state *state;
 213         struct sockaddr_un sunaddr;
 214         struct stat st;
 215         char *path = NULL;
 216         wbcErr wbc_err;
 217
 218         result = tevent_req_create(mem_ctx, &state, struct wb_connect_state);
 219         if (result == NULL) {
 220                 return NULL;
 221         }
 222
 223         if (wb_ctx->fd != -1) {
 224                 close(wb_ctx->fd);
 225                 wb_ctx->fd = -1;
 226         }
 227
 228         /* Check permissions on unix socket directory */
 229
 230         if (lstat(dir, &st) == -1) {
 231                 wbc_err = WBC_ERR_WINBIND_NOT_AVAILABLE;
 232                 goto post_status;
 233         }
 234
 235         if (!S_ISDIR(st.st_mode) ||
 236             (st.st_uid != 0 && st.st_uid != geteuid())) {
 237                 wbc_err = WBC_ERR_WINBIND_NOT_AVAILABLE;
 238                 goto post_status;
 239         }
 240
 241         /* Connect to socket */
 242
 243         path = talloc_asprintf(talloc_tos(), "%s/%s", dir,
 244                                WINBINDD_SOCKET_NAME);
 245         if (path == NULL) {
 246                 goto nomem;
 247         }
 248
 249         sunaddr.sun_family = AF_UNIX;
 250         strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path));
 251         TALLOC_FREE(path);
 252
 253         /* If socket file doesn't exist, don't bother trying to connect
 254            with retry.  This is an attempt to make the system usable when
 255            the winbindd daemon is not running. */
 256
 257         if ((lstat(sunaddr.sun_path, &st) == -1)
 258             || !S_ISSOCK(st.st_mode)
 259             || (st.st_uid != 0 && st.st_uid != geteuid())) {
 260                 wbc_err = WBC_ERR_WINBIND_NOT_AVAILABLE;
 261                 goto post_status;
 262         }
 263
 264         wb_ctx->fd = make_safe_fd(socket(AF_UNIX, SOCK_STREAM, 0));
 265         if (wb_ctx->fd == -1) {
 266                 wbc_err = map_wbc_err_from_errno(errno);
 267                 goto post_status;
 268         }
 269
 270         subreq = async_connect_send(mem_ctx, ev, wb_ctx->fd,
 271                                     (struct sockaddr *)(void *)&sunaddr,
 272                                     sizeof(sunaddr));
 273         if (subreq == NULL) {
 274                 goto nomem;
 275         }
 276         tevent_req_set_callback(subreq, wbc_connect_connected, result);
 277         return result;
 278
 279  post_status:
 280         tevent_req_error(result, wbc_err);
 281         return tevent_req_post(result, ev);
 282  nomem:
 283         TALLOC_FREE(result);
 284         return NULL;
 285 }
 286
 287 static void wbc_connect_connected(struct tevent_req *subreq)
 288 {
 289         struct tevent_req *req = tevent_req_callback_data(
 290                 subreq, struct tevent_req);
 291         int res, err;
 292
 293         res = async_connect_recv(subreq, &err);
 294         TALLOC_FREE(subreq);
 295         if (res == -1) {
 296                 tevent_req_error(req, map_wbc_err_from_errno(err));
 297                 return;
 298         }
 299         tevent_req_done(req);
 300 }
 301
 302 static wbcErr wb_connect_recv(struct tevent_req *req)
 303 {
 304         return tevent_req_simple_recv_wbcerr(req);
 305 }
 306
 307 static const char *winbindd_socket_dir(void)
 308 {
 309 #ifdef SOCKET_WRAPPER
 310         const char *env_dir;
 311
 312         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 313         if (env_dir) {
 314                 return env_dir;
 315         }
 316 #endif
 317
 318         return WINBINDD_SOCKET_DIR;
 319 }
 320
 321 struct wb_open_pipe_state {
 322         struct wb_context *wb_ctx;
 323         struct tevent_context *ev;
 324         bool need_priv;
 325         struct winbindd_request wb_req;
 326 };
 327
 328 static void wb_open_pipe_connect_nonpriv_done(struct tevent_req *subreq);
 329 static void wb_open_pipe_ping_done(struct tevent_req *subreq);
 330 static void wb_open_pipe_getpriv_done(struct tevent_req *subreq);
 331 static void wb_open_pipe_connect_priv_done(struct tevent_req *subreq);
 332
 333 static struct tevent_req *wb_open_pipe_send(TALLOC_CTX *mem_ctx,
 334                                             struct tevent_context *ev,
 335                                             struct wb_context *wb_ctx,
 336                                             bool need_priv)
 337 {
 338         struct tevent_req *result, *subreq;
 339         struct wb_open_pipe_state *state;
 340
 341         result = tevent_req_create(mem_ctx, &state, struct wb_open_pipe_state);
 342         if (result == NULL) {
 343                 return NULL;
 344         }
 345         state->wb_ctx = wb_ctx;
 346         state->ev = ev;
 347         state->need_priv = need_priv;
 348
 349         if (wb_ctx->fd != -1) {
 350                 close(wb_ctx->fd);
 351                 wb_ctx->fd = -1;
 352         }
 353
 354         subreq = wb_connect_send(state, ev, wb_ctx, winbindd_socket_dir());
 355         if (subreq == NULL) {
 356                 goto fail;
 357         }
 358         tevent_req_set_callback(subreq, wb_open_pipe_connect_nonpriv_done,
 359                                 result);
 360         return result;
 361
 362  fail:
 363         TALLOC_FREE(result);
 364         return NULL;
 365 }
 366
 367 static void wb_open_pipe_connect_nonpriv_done(struct tevent_req *subreq)
 368 {
 369         struct tevent_req *req = tevent_req_callback_data(
 370                 subreq, struct tevent_req);
 371         struct wb_open_pipe_state *state = tevent_req_data(
 372                 req, struct wb_open_pipe_state);
 373         wbcErr wbc_err;
 374
 375         wbc_err = wb_connect_recv(subreq);
 376         TALLOC_FREE(subreq);
 377         if (!WBC_ERROR_IS_OK(wbc_err)) {
 378                 state->wb_ctx->is_priv = true;
 379                 tevent_req_error(req, wbc_err);
 380                 return;
 381         }
 382
 383         ZERO_STRUCT(state->wb_req);
 384         state->wb_req.cmd = WINBINDD_INTERFACE_VERSION;
 385         state->wb_req.pid = getpid();
 386
 387         subreq = wb_simple_trans_send(state, state->ev, NULL,
 388                                       state->wb_ctx->fd, &state->wb_req);
 389         if (tevent_req_nomem(subreq, req)) {
 390                 return;
 391         }
 392         tevent_req_set_callback(subreq, wb_open_pipe_ping_done, req);
 393 }
 394
 395 static void wb_open_pipe_ping_done(struct tevent_req *subreq)
 396 {
 397         struct tevent_req *req = tevent_req_callback_data(
 398                 subreq, struct tevent_req);
 399         struct wb_open_pipe_state *state = tevent_req_data(
 400                 req, struct wb_open_pipe_state);
 401         struct winbindd_response *wb_resp;
 402         int ret, err;
 403
 404         ret = wb_simple_trans_recv(subreq, state, &wb_resp, &err);
 405         TALLOC_FREE(subreq);
 406         if (ret == -1) {
 407                 tevent_req_error(req, map_wbc_err_from_errno(err));
 408                 return;
 409         }
 410
 411         if (!state->need_priv) {
 412                 tevent_req_done(req);
 413                 return;
 414         }
 415
 416         state->wb_req.cmd = WINBINDD_PRIV_PIPE_DIR;
 417         state->wb_req.pid = getpid();
 418
 419         subreq = wb_simple_trans_send(state, state->ev, NULL,
 420                                       state->wb_ctx->fd, &state->wb_req);
 421         if (tevent_req_nomem(subreq, req)) {
 422                 return;
 423         }
 424         tevent_req_set_callback(subreq, wb_open_pipe_getpriv_done, req);
 425 }
 426
 427 static void wb_open_pipe_getpriv_done(struct tevent_req *subreq)
 428 {
 429         struct tevent_req *req = tevent_req_callback_data(
 430                 subreq, struct tevent_req);
 431         struct wb_open_pipe_state *state = tevent_req_data(
 432                 req, struct wb_open_pipe_state);
 433         struct winbindd_response *wb_resp = NULL;
 434         int ret, err;
 435
 436         ret = wb_simple_trans_recv(subreq, state, &wb_resp, &err);
 437         TALLOC_FREE(subreq);
 438         if (ret == -1) {
 439                 tevent_req_error(req, map_wbc_err_from_errno(err));
 440                 return;
 441         }
 442
 443         close(state->wb_ctx->fd);
 444         state->wb_ctx->fd = -1;
 445
 446         subreq = wb_connect_send(state, state->ev, state->wb_ctx,
 447                                   (char *)wb_resp->extra_data.data);
 448         TALLOC_FREE(wb_resp);
 449         if (tevent_req_nomem(subreq, req)) {
 450                 return;
 451         }
 452         tevent_req_set_callback(subreq, wb_open_pipe_connect_priv_done, req);
 453 }
 454
 455 static void wb_open_pipe_connect_priv_done(struct tevent_req *subreq)
 456 {
 457         struct tevent_req *req = tevent_req_callback_data(
 458                 subreq, struct tevent_req);
 459         struct wb_open_pipe_state *state = tevent_req_data(
 460                 req, struct wb_open_pipe_state);
 461         wbcErr wbc_err;
 462
 463         wbc_err = wb_connect_recv(subreq);
 464         TALLOC_FREE(subreq);
 465         if (!WBC_ERROR_IS_OK(wbc_err)) {
 466                 tevent_req_error(req, wbc_err);
 467                 return;
 468         }
 469         state->wb_ctx->is_priv = true;
 470         tevent_req_done(req);
 471 }
 472
 473 static wbcErr wb_open_pipe_recv(struct tevent_req *req)
 474 {
 475         return tevent_req_simple_recv_wbcerr(req);
 476 }
 477
 478 struct wb_trans_state {
 479         struct wb_trans_state *prev, *next;
 480         struct wb_context *wb_ctx;
 481         struct tevent_context *ev;
 482         struct winbindd_request *wb_req;
 483         struct winbindd_response *wb_resp;
 484         bool need_priv;
 485 };
 486
 487 static bool closed_fd(int fd)
 488 {
 489         struct timeval tv;
 490         fd_set r_fds;
 491         int selret;
 492
 493         if (fd == -1) {
 494                 return true;
 495         }
 496
 497         FD_ZERO(&r_fds);
 498         FD_SET(fd, &r_fds);
 499         ZERO_STRUCT(tv);
 500
 501         selret = select(fd+1, &r_fds, NULL, NULL, &tv);
 502         if (selret == -1) {
 503                 return true;
 504         }
 505         if (selret == 0) {
 506                 return false;
 507         }
 508         return (FD_ISSET(fd, &r_fds));
 509 }
 510
 511 static void wb_trans_trigger(struct tevent_req *req, void *private_data);
 512 static void wb_trans_connect_done(struct tevent_req *subreq);
 513 static void wb_trans_done(struct tevent_req *subreq);
 514 static void wb_trans_retry_wait_done(struct tevent_req *subreq);
 515
 516 struct tevent_req *wb_trans_send(TALLOC_CTX *mem_ctx,
 517                                  struct tevent_context *ev,
 518                                  struct wb_context *wb_ctx, bool need_priv,
 519                                  struct winbindd_request *wb_req)
 520 {
 521         struct tevent_req *req;
 522         struct wb_trans_state *state;
 523
 524         req = tevent_req_create(mem_ctx, &state, struct wb_trans_state);
 525         if (req == NULL) {
 526                 return NULL;
 527         }
 528         state->wb_ctx = wb_ctx;
 529         state->ev = ev;
 530         state->wb_req = wb_req;
 531         state->need_priv = need_priv;
 532
 533         if (!tevent_queue_add(wb_ctx->queue, ev, req, wb_trans_trigger,
 534                               NULL)) {
 535                 tevent_req_nomem(NULL, req);
 536                 return tevent_req_post(req, ev);
 537         }
 538         return req;
 539 }
 540
 541 static void wb_trans_trigger(struct tevent_req *req, void *private_data)
 542 {
 543         struct wb_trans_state *state = tevent_req_data(
 544                 req, struct wb_trans_state);
 545         struct tevent_req *subreq;
 546
 547         if ((state->wb_ctx->fd != -1) && closed_fd(state->wb_ctx->fd)) {
 548                 close(state->wb_ctx->fd);
 549                 state->wb_ctx->fd = -1;
 550         }
 551
 552         if ((state->wb_ctx->fd == -1)
 553             || (state->need_priv && !state->wb_ctx->is_priv)) {
 554                 subreq = wb_open_pipe_send(state, state->ev, state->wb_ctx,
 555                                            state->need_priv);
 556                 if (tevent_req_nomem(subreq, req)) {
 557                         return;
 558                 }
 559                 tevent_req_set_callback(subreq, wb_trans_connect_done, req);
 560                 return;
 561         }
 562
 563         state->wb_req->pid = getpid();
 564
 565         subreq = wb_simple_trans_send(state, state->ev, NULL,
 566                                       state->wb_ctx->fd, state->wb_req);
 567         if (tevent_req_nomem(subreq, req)) {
 568                 return;
 569         }
 570         tevent_req_set_callback(subreq, wb_trans_done, req);
 571 }
 572
 573 static bool wb_trans_retry(struct tevent_req *req,
 574                            struct wb_trans_state *state,
 575                            wbcErr wbc_err)
 576 {
 577         struct tevent_req *subreq;
 578
 579         if (WBC_ERROR_IS_OK(wbc_err)) {
 580                 return false;
 581         }
 582
 583         if (wbc_err == WBC_ERR_WINBIND_NOT_AVAILABLE) {
 584                 /*
 585                  * Winbind not around or we can't connect to the pipe. Fail
 586                  * immediately.
 587                  */
 588                 tevent_req_error(req, wbc_err);
 589                 return true;
 590         }
 591
 592         /*
 593          * The transfer as such failed, retry after one second
 594          */
 595
 596         if (state->wb_ctx->fd != -1) {
 597                 close(state->wb_ctx->fd);
 598                 state->wb_ctx->fd = -1;
 599         }
 600
 601         subreq = tevent_wakeup_send(state, state->ev,
 602                                     timeval_current_ofs(1, 0));
 603         if (tevent_req_nomem(subreq, req)) {
 604                 return true;
 605         }
 606         tevent_req_set_callback(subreq, wb_trans_retry_wait_done, req);
 607         return true;
 608 }
 609
 610 static void wb_trans_retry_wait_done(struct tevent_req *subreq)
 611 {
 612         struct tevent_req *req = tevent_req_callback_data(
 613                 subreq, struct tevent_req);
 614         struct wb_trans_state *state = tevent_req_data(
 615                 req, struct wb_trans_state);
 616         bool ret;
 617
 618         ret = tevent_wakeup_recv(subreq);
 619         TALLOC_FREE(subreq);
 620         if (!ret) {
 621                 tevent_req_error(req, WBC_ERR_UNKNOWN_FAILURE);
 622                 return;
 623         }
 624
 625         subreq = wb_open_pipe_send(state, state->ev, state->wb_ctx,
 626                                    state->need_priv);
 627         if (tevent_req_nomem(subreq, req)) {
 628                 return;
 629         }
 630         tevent_req_set_callback(subreq, wb_trans_connect_done, req);
 631 }
 632
 633 static void wb_trans_connect_done(struct tevent_req *subreq)
 634 {
 635         struct tevent_req *req = tevent_req_callback_data(
 636                 subreq, struct tevent_req);
 637         struct wb_trans_state *state = tevent_req_data(
 638                 req, struct wb_trans_state);
 639         wbcErr wbc_err;
 640
 641         wbc_err = wb_open_pipe_recv(subreq);
 642         TALLOC_FREE(subreq);
 643
 644         if (wb_trans_retry(req, state, wbc_err)) {
 645                 return;
 646         }
 647
 648         subreq = wb_simple_trans_send(state, state->ev, NULL,
 649                                       state->wb_ctx->fd, state->wb_req);
 650         if (tevent_req_nomem(subreq, req)) {
 651                 return;
 652         }
 653         tevent_req_set_callback(subreq, wb_trans_done, req);
 654 }
 655
 656 static void wb_trans_done(struct tevent_req *subreq)
 657 {
 658         struct tevent_req *req = tevent_req_callback_data(
 659                 subreq, struct tevent_req);
 660         struct wb_trans_state *state = tevent_req_data(
 661                 req, struct wb_trans_state);
 662         int ret, err;
 663
 664         ret = wb_simple_trans_recv(subreq, state, &state->wb_resp, &err);
 665         TALLOC_FREE(subreq);
 666         if ((ret == -1)
 667             && wb_trans_retry(req, state, map_wbc_err_from_errno(err))) {
 668                 return;
 669         }
 670
 671         tevent_req_done(req);
 672 }
 673
 674 wbcErr wb_trans_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 675                      struct winbindd_response **presponse)
 676 {
 677         struct wb_trans_state *state = tevent_req_data(
 678                 req, struct wb_trans_state);
 679         wbcErr wbc_err;
 680
 681         if (tevent_req_is_wbcerr(req, &wbc_err)) {
 682                 return wbc_err;
 683         }
 684
 685         *presponse = talloc_move(mem_ctx, &state->wb_resp);
 686         return WBC_ERR_SUCCESS;
 687 }