nsswitch/wb_common.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    winbind client common code
   5
   6    Copyright (C) Tim Potter 2000
   7    Copyright (C) Andrew Tridgell 2000
   8    Copyright (C) Andrew Bartlett 2002
   9
  10
  11    This library is free software; you can redistribute it and/or
  12    modify it under the terms of the GNU Lesser General Public
  13    License as published by the Free Software Foundation; either
  14    version 3 of the License, or (at your option) any later version.
  15
  16    This library is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Library General Public License for more details.
  20
  21    You should have received a copy of the GNU Lesser General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "winbind_client.h"
  26
  27 /* Global variables.  These are effectively the client state information */
  28
  29 int winbindd_fd = -1;           /* fd for winbindd socket */
  30 static int is_privileged = 0;
  31
  32 /* Free a response structure */
  33
  34 void winbindd_free_response(struct winbindd_response *response)
  35 {
  36         /* Free any allocated extra_data */
  37
  38         if (response)
  39                 SAFE_FREE(response->extra_data.data);
  40 }
  41
  42 /* Initialise a request structure */
  43
  44 void winbindd_init_request(struct winbindd_request *request, int request_type)
  45 {
  46         request->length = sizeof(struct winbindd_request);
  47
  48         request->cmd = (enum winbindd_cmd)request_type;
  49         request->pid = getpid();
  50
  51 }
  52
  53 /* Initialise a response structure */
  54
  55 static void init_response(struct winbindd_response *response)
  56 {
  57         /* Initialise return value */
  58
  59         response->result = WINBINDD_ERROR;
  60 }
  61
  62 /* Close established socket */
  63
  64 #if HAVE_FUNCTION_ATTRIBUTE_DESTRUCTOR
  65 __attribute__((destructor))
  66 #endif
  67 void winbind_close_sock(void)
  68 {
  69         if (winbindd_fd != -1) {
  70                 close(winbindd_fd);
  71                 winbindd_fd = -1;
  72         }
  73 }
  74
  75 #define CONNECT_TIMEOUT 30
  76
  77 /* Make sure socket handle isn't stdin, stdout or stderr */
  78 #define RECURSION_LIMIT 3
  79
  80 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  81 {
  82         int new_fd;
  83         if (fd >= 0 && fd <= 2) {
  84 #ifdef F_DUPFD
  85                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  86                         return -1;
  87                 }
  88                 /* Paranoia */
  89                 if (new_fd < 3) {
  90                         close(new_fd);
  91                         return -1;
  92                 }
  93                 close(fd);
  94                 return new_fd;
  95 #else
  96                 if (limit <= 0)
  97                         return -1;
  98
  99                 new_fd = dup(fd);
 100                 if (new_fd == -1)
 101                         return -1;
 102
 103                 /* use the program stack to hold our list of FDs to close */
 104                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 105                 close(fd);
 106                 return new_fd;
 107 #endif
 108         }
 109         return fd;
 110 }
 111
 112 /****************************************************************************
 113  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 114  else
 115  if SYSV use O_NDELAY
 116  if BSD use FNDELAY
 117  Set close on exec also.
 118 ****************************************************************************/
 119
 120 static int make_safe_fd(int fd)
 121 {
 122         int result, flags;
 123         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 124         if (new_fd == -1) {
 125                 close(fd);
 126                 return -1;
 127         }
 128
 129         /* Socket should be nonblocking. */
 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                 close(new_fd);
 142                 return -1;
 143         }
 144
 145         flags |= FLAG_TO_SET;
 146         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 147                 close(new_fd);
 148                 return -1;
 149         }
 150
 151 #undef FLAG_TO_SET
 152
 153         /* Socket should be closed on exec() */
 154 #ifdef FD_CLOEXEC
 155         result = flags = fcntl(new_fd, F_GETFD, 0);
 156         if (flags >= 0) {
 157                 flags |= FD_CLOEXEC;
 158                 result = fcntl( new_fd, F_SETFD, flags );
 159         }
 160         if (result < 0) {
 161                 close(new_fd);
 162                 return -1;
 163         }
 164 #endif
 165         return new_fd;
 166 }
 167
 168 /* Connect to winbindd socket */
 169
 170 static int winbind_named_pipe_sock(const char *dir)
 171 {
 172         struct sockaddr_un sunaddr;
 173         struct stat st;
 174         char *path = NULL;
 175         int fd;
 176         int wait_time;
 177         int slept;
 178
 179         /* Check permissions on unix socket directory */
 180
 181         if (lstat(dir, &st) == -1) {
 182                 errno = ENOENT;
 183                 return -1;
 184         }
 185
 186         if (!S_ISDIR(st.st_mode) ||
 187             (st.st_uid != 0 && st.st_uid != geteuid())) {
 188                 errno = ENOENT;
 189                 return -1;
 190         }
 191
 192         /* Connect to socket */
 193
 194         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 195                 return -1;
 196         }
 197
 198         ZERO_STRUCT(sunaddr);
 199         sunaddr.sun_family = AF_UNIX;
 200         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 201
 202         /* If socket file doesn't exist, don't bother trying to connect
 203            with retry.  This is an attempt to make the system usable when
 204            the winbindd daemon is not running. */
 205
 206         if (lstat(path, &st) == -1) {
 207                 errno = ENOENT;
 208                 SAFE_FREE(path);
 209                 return -1;
 210         }
 211
 212         SAFE_FREE(path);
 213         /* Check permissions on unix socket file */
 214
 215         if (!S_ISSOCK(st.st_mode) ||
 216             (st.st_uid != 0 && st.st_uid != geteuid())) {
 217                 errno = ENOENT;
 218                 return -1;
 219         }
 220
 221         /* Connect to socket */
 222
 223         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 224                 return -1;
 225         }
 226
 227         /* Set socket non-blocking and close on exec. */
 228
 229         if ((fd = make_safe_fd( fd)) == -1) {
 230                 return fd;
 231         }
 232
 233         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 234                         wait_time += slept) {
 235                 struct timeval tv;
 236                 fd_set w_fds;
 237                 int ret;
 238                 int connect_errno = 0;
 239                 socklen_t errnosize;
 240
 241                 if (wait_time >= CONNECT_TIMEOUT)
 242                         goto error_out;
 243
 244                 switch (errno) {
 245                         case EINPROGRESS:
 246                                 FD_ZERO(&w_fds);
 247                                 if (fd < 0 || fd >= FD_SETSIZE) {
 248                                         errno = EBADF;
 249                                         goto error_out;
 250                                 }
 251                                 FD_SET(fd, &w_fds);
 252                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 253                                 tv.tv_usec = 0;
 254
 255                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 256
 257                                 if (ret > 0) {
 258                                         errnosize = sizeof(connect_errno);
 259
 260                                         ret = getsockopt(fd, SOL_SOCKET,
 261                                                         SO_ERROR, &connect_errno, &errnosize);
 262
 263                                         if (ret >= 0 && connect_errno == 0) {
 264                                                 /* Connect succeed */
 265                                                 goto out;
 266                                         }
 267                                 }
 268
 269                                 slept = CONNECT_TIMEOUT;
 270                                 break;
 271                         case EAGAIN:
 272                                 slept = rand() % 3 + 1;
 273                                 sleep(slept);
 274                                 break;
 275                         default:
 276                                 goto error_out;
 277                 }
 278
 279         }
 280
 281   out:
 282
 283         return fd;
 284
 285   error_out:
 286
 287         close(fd);
 288         return -1;
 289 }
 290
 291 static const char *winbindd_socket_dir(void)
 292 {
 293 #ifdef SOCKET_WRAPPER
 294         const char *env_dir;
 295
 296         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 297         if (env_dir) {
 298                 return env_dir;
 299         }
 300 #endif
 301
 302         return WINBINDD_SOCKET_DIR;
 303 }
 304
 305 /* Connect to winbindd socket */
 306
 307 static int winbind_open_pipe_sock(int recursing, int need_priv)
 308 {
 309 #ifdef HAVE_UNIXSOCKET
 310         static pid_t our_pid;
 311         struct winbindd_request request;
 312         struct winbindd_response response;
 313         ZERO_STRUCT(request);
 314         ZERO_STRUCT(response);
 315
 316         if (our_pid != getpid()) {
 317                 winbind_close_sock();
 318                 our_pid = getpid();
 319         }
 320
 321         if ((need_priv != 0) && (is_privileged == 0)) {
 322                 winbind_close_sock();
 323         }
 324
 325         if (winbindd_fd != -1) {
 326                 return winbindd_fd;
 327         }
 328
 329         if (recursing) {
 330                 return -1;
 331         }
 332
 333         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 334                 return -1;
 335         }
 336
 337         is_privileged = 0;
 338
 339         /* version-check the socket */
 340
 341         request.wb_flags = WBFLAG_RECURSE;
 342         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 343                 winbind_close_sock();
 344                 return -1;
 345         }
 346
 347         /* try and get priv pipe */
 348
 349         request.wb_flags = WBFLAG_RECURSE;
 350         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 351                 int fd;
 352                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 353                         close(winbindd_fd);
 354                         winbindd_fd = fd;
 355                         is_privileged = 1;
 356                 }
 357         }
 358
 359         if ((need_priv != 0) && (is_privileged == 0)) {
 360                 return -1;
 361         }
 362
 363         SAFE_FREE(response.extra_data.data);
 364
 365         return winbindd_fd;
 366 #else
 367         return -1;
 368 #endif /* HAVE_UNIXSOCKET */
 369 }
 370
 371 /* Write data to winbindd socket */
 372
 373 int winbind_write_sock(void *buffer, int count, int recursing, int need_priv)
 374 {
 375         int result, nwritten;
 376
 377         /* Open connection to winbind daemon */
 378
 379  restart:
 380
 381         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 382                 errno = ENOENT;
 383                 return -1;
 384         }
 385
 386         /* Write data to socket */
 387
 388         nwritten = 0;
 389
 390         while(nwritten < count) {
 391                 struct timeval tv;
 392                 fd_set r_fds;
 393
 394                 /* Catch pipe close on other end by checking if a read()
 395                    call would not block by calling select(). */
 396
 397                 FD_ZERO(&r_fds);
 398                 if (winbindd_fd < 0 || winbindd_fd >= FD_SETSIZE) {
 399                         errno = EBADF;
 400                         winbind_close_sock();
 401                         return -1;
 402                 }
 403                 FD_SET(winbindd_fd, &r_fds);
 404                 ZERO_STRUCT(tv);
 405
 406                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 407                         winbind_close_sock();
 408                         return -1;                   /* Select error */
 409                 }
 410
 411                 /* Write should be OK if fd not available for reading */
 412
 413                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 414
 415                         /* Do the write */
 416
 417                         result = write(winbindd_fd,
 418                                        (char *)buffer + nwritten,
 419                                        count - nwritten);
 420
 421                         if ((result == -1) || (result == 0)) {
 422
 423                                 /* Write failed */
 424
 425                                 winbind_close_sock();
 426                                 return -1;
 427                         }
 428
 429                         nwritten += result;
 430
 431                 } else {
 432
 433                         /* Pipe has closed on remote end */
 434
 435                         winbind_close_sock();
 436                         goto restart;
 437                 }
 438         }
 439
 440         return nwritten;
 441 }
 442
 443 /* Read data from winbindd socket */
 444
 445 int winbind_read_sock(void *buffer, int count)
 446 {
 447         int nread = 0;
 448         int total_time = 0, selret;
 449
 450         if (winbindd_fd == -1) {
 451                 return -1;
 452         }
 453
 454         /* Read data from socket */
 455         while(nread < count) {
 456                 struct timeval tv;
 457                 fd_set r_fds;
 458
 459                 /* Catch pipe close on other end by checking if a read()
 460                    call would not block by calling select(). */
 461
 462                 FD_ZERO(&r_fds);
 463                 if (winbindd_fd < 0 || winbindd_fd >= FD_SETSIZE) {
 464                         errno = EBADF;
 465                         winbind_close_sock();
 466                         return -1;
 467                 }
 468                 FD_SET(winbindd_fd, &r_fds);
 469                 ZERO_STRUCT(tv);
 470                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 471                 tv.tv_sec = 5;
 472
 473                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 474                         winbind_close_sock();
 475                         return -1;                   /* Select error */
 476                 }
 477
 478                 if (selret == 0) {
 479                         /* Not ready for read yet... */
 480                         if (total_time >= 30) {
 481                                 /* Timeout */
 482                                 winbind_close_sock();
 483                                 return -1;
 484                         }
 485                         total_time += 5;
 486                         continue;
 487                 }
 488
 489                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 490
 491                         /* Do the Read */
 492
 493                         int result = read(winbindd_fd, (char *)buffer + nread,
 494                               count - nread);
 495
 496                         if ((result == -1) || (result == 0)) {
 497
 498                                 /* Read failed.  I think the only useful thing we
 499                                    can do here is just return -1 and fail since the
 500                                    transaction has failed half way through. */
 501
 502                                 winbind_close_sock();
 503                                 return -1;
 504                         }
 505
 506                         nread += result;
 507
 508                 }
 509         }
 510
 511         return nread;
 512 }
 513
 514 /* Read reply */
 515
 516 int winbindd_read_reply(struct winbindd_response *response)
 517 {
 518         int result1, result2 = 0;
 519
 520         if (!response) {
 521                 return -1;
 522         }
 523
 524         /* Read fixed length response */
 525
 526         result1 = winbind_read_sock(response,
 527                                     sizeof(struct winbindd_response));
 528         if (result1 == -1) {
 529                 return -1;
 530         }
 531
 532         /* We actually send the pointer value of the extra_data field from
 533            the server.  This has no meaning in the client's address space
 534            so we clear it out. */
 535
 536         response->extra_data.data = NULL;
 537
 538         /* Read variable length response */
 539
 540         if (response->length > sizeof(struct winbindd_response)) {
 541                 int extra_data_len = response->length -
 542                         sizeof(struct winbindd_response);
 543
 544                 /* Mallocate memory for extra data */
 545
 546                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 547                         return -1;
 548                 }
 549
 550                 result2 = winbind_read_sock(response->extra_data.data,
 551                                             extra_data_len);
 552                 if (result2 == -1) {
 553                         winbindd_free_response(response);
 554                         return -1;
 555                 }
 556         }
 557
 558         /* Return total amount of data read */
 559
 560         return result1 + result2;
 561 }
 562
 563 /*
 564  * send simple types of requests
 565  */
 566
 567 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 568                                  struct winbindd_request *request)
 569 {
 570         struct winbindd_request lrequest;
 571
 572         /* Check for our tricky environment variable */
 573
 574         if (winbind_env_set()) {
 575                 return NSS_STATUS_NOTFOUND;
 576         }
 577
 578         if (!request) {
 579                 ZERO_STRUCT(lrequest);
 580                 request = &lrequest;
 581         }
 582
 583         /* Fill in request and send down pipe */
 584
 585         winbindd_init_request(request, req_type);
 586
 587         if (winbind_write_sock(request, sizeof(*request),
 588                                request->wb_flags & WBFLAG_RECURSE,
 589                                need_priv) == -1)
 590         {
 591                 /* Set ENOENT for consistency.  Required by some apps */
 592                 errno = ENOENT;
 593
 594                 return NSS_STATUS_UNAVAIL;
 595         }
 596
 597         if ((request->extra_len != 0) &&
 598             (winbind_write_sock(request->extra_data.data,
 599                                 request->extra_len,
 600                                 request->wb_flags & WBFLAG_RECURSE,
 601                                 need_priv) == -1))
 602         {
 603                 /* Set ENOENT for consistency.  Required by some apps */
 604                 errno = ENOENT;
 605
 606                 return NSS_STATUS_UNAVAIL;
 607         }
 608
 609         return NSS_STATUS_SUCCESS;
 610 }
 611
 612 /*
 613  * Get results from winbindd request
 614  */
 615
 616 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 617 {
 618         struct winbindd_response lresponse;
 619
 620         if (!response) {
 621                 ZERO_STRUCT(lresponse);
 622                 response = &lresponse;
 623         }
 624
 625         init_response(response);
 626
 627         /* Wait for reply */
 628         if (winbindd_read_reply(response) == -1) {
 629                 /* Set ENOENT for consistency.  Required by some apps */
 630                 errno = ENOENT;
 631
 632                 return NSS_STATUS_UNAVAIL;
 633         }
 634
 635         /* Throw away extra data if client didn't request it */
 636         if (response == &lresponse) {
 637                 winbindd_free_response(response);
 638         }
 639
 640         /* Copy reply data from socket */
 641         if (response->result != WINBINDD_OK) {
 642                 return NSS_STATUS_NOTFOUND;
 643         }
 644
 645         return NSS_STATUS_SUCCESS;
 646 }
 647
 648 /* Handle simple types of requests */
 649
 650 NSS_STATUS winbindd_request_response(int req_type,
 651                             struct winbindd_request *request,
 652                             struct winbindd_response *response)
 653 {
 654         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 655         int count = 0;
 656
 657         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 658                 status = winbindd_send_request(req_type, 0, request);
 659                 if (status != NSS_STATUS_SUCCESS)
 660                         return(status);
 661                 status = winbindd_get_response(response);
 662                 count += 1;
 663         }
 664
 665         return status;
 666 }
 667
 668 NSS_STATUS winbindd_priv_request_response(int req_type,
 669                                           struct winbindd_request *request,
 670                                           struct winbindd_response *response)
 671 {
 672         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 673         int count = 0;
 674
 675         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 676                 status = winbindd_send_request(req_type, 1, request);
 677                 if (status != NSS_STATUS_SUCCESS)
 678                         return(status);
 679                 status = winbindd_get_response(response);
 680                 count += 1;
 681         }
 682
 683         return status;
 684 }
 685
 686 /*************************************************************************
 687  ************************************************************************/
 688
 689 const char *nss_err_str(NSS_STATUS ret)
 690 {
 691         switch (ret) {
 692                 case NSS_STATUS_TRYAGAIN:
 693                         return "NSS_STATUS_TRYAGAIN";
 694                 case NSS_STATUS_SUCCESS:
 695                         return "NSS_STATUS_SUCCESS";
 696                 case NSS_STATUS_NOTFOUND:
 697                         return "NSS_STATUS_NOTFOUND";
 698                 case NSS_STATUS_UNAVAIL:
 699                         return "NSS_STATUS_UNAVAIL";
 700 #ifdef NSS_STATUS_RETURN
 701                 case NSS_STATUS_RETURN:
 702                         return "NSS_STATUS_RETURN";
 703 #endif
 704                 default:
 705                         return "UNKNOWN RETURN CODE!!!!!!!";
 706         }
 707 }