source/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 void winbind_close_sock(void)
  65 {
  66         if (winbindd_fd != -1) {
  67                 close(winbindd_fd);
  68                 winbindd_fd = -1;
  69         }
  70 }
  71
  72 #define CONNECT_TIMEOUT 30
  73
  74 /* Make sure socket handle isn't stdin, stdout or stderr */
  75 #define RECURSION_LIMIT 3
  76
  77 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  78 {
  79         int new_fd;
  80         if (fd >= 0 && fd <= 2) {
  81 #ifdef F_DUPFD
  82                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  83                         return -1;
  84                 }
  85                 /* Paranoia */
  86                 if (new_fd < 3) {
  87                         close(new_fd);
  88                         return -1;
  89                 }
  90                 close(fd);
  91                 return new_fd;
  92 #else
  93                 if (limit <= 0)
  94                         return -1;
  95
  96                 new_fd = dup(fd);
  97                 if (new_fd == -1)
  98                         return -1;
  99
 100                 /* use the program stack to hold our list of FDs to close */
 101                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 102                 close(fd);
 103                 return new_fd;
 104 #endif
 105         }
 106         return fd;
 107 }
 108
 109 /****************************************************************************
 110  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 111  else
 112  if SYSV use O_NDELAY
 113  if BSD use FNDELAY
 114  Set close on exec also.
 115 ****************************************************************************/
 116
 117 static int make_safe_fd(int fd)
 118 {
 119         int result, flags;
 120         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 121         if (new_fd == -1) {
 122                 close(fd);
 123                 return -1;
 124         }
 125
 126         /* Socket should be nonblocking. */
 127 #ifdef O_NONBLOCK
 128 #define FLAG_TO_SET O_NONBLOCK
 129 #else
 130 #ifdef SYSV
 131 #define FLAG_TO_SET O_NDELAY
 132 #else /* BSD */
 133 #define FLAG_TO_SET FNDELAY
 134 #endif
 135 #endif
 136
 137         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 138                 close(new_fd);
 139                 return -1;
 140         }
 141
 142         flags |= FLAG_TO_SET;
 143         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 144                 close(new_fd);
 145                 return -1;
 146         }
 147
 148 #undef FLAG_TO_SET
 149
 150         /* Socket should be closed on exec() */
 151 #ifdef FD_CLOEXEC
 152         result = flags = fcntl(new_fd, F_GETFD, 0);
 153         if (flags >= 0) {
 154                 flags |= FD_CLOEXEC;
 155                 result = fcntl( new_fd, F_SETFD, flags );
 156         }
 157         if (result < 0) {
 158                 close(new_fd);
 159                 return -1;
 160         }
 161 #endif
 162         return new_fd;
 163 }
 164
 165 /* Connect to winbindd socket */
 166
 167 static int winbind_named_pipe_sock(const char *dir)
 168 {
 169         struct sockaddr_un sunaddr;
 170         struct stat st;
 171         pstring path;
 172         int fd;
 173         int wait_time;
 174         int slept;
 175
 176         /* Check permissions on unix socket directory */
 177
 178         if (lstat(dir, &st) == -1) {
 179                 return -1;
 180         }
 181
 182         if (!S_ISDIR(st.st_mode) ||
 183             (st.st_uid != 0 && st.st_uid != geteuid())) {
 184                 return -1;
 185         }
 186
 187         /* Connect to socket */
 188
 189         strncpy(path, dir, sizeof(path) - 1);
 190         path[sizeof(path) - 1] = '\0';
 191
 192         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 193         path[sizeof(path) - 1] = '\0';
 194
 195         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 196         path[sizeof(path) - 1] = '\0';
 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                 return -1;
 208         }
 209
 210         /* Check permissions on unix socket file */
 211
 212         if (!S_ISSOCK(st.st_mode) ||
 213             (st.st_uid != 0 && st.st_uid != geteuid())) {
 214                 return -1;
 215         }
 216
 217         /* Connect to socket */
 218
 219         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 220                 return -1;
 221         }
 222
 223         /* Set socket non-blocking and close on exec. */
 224
 225         if ((fd = make_safe_fd( fd)) == -1) {
 226                 return fd;
 227         }
 228
 229         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 230                         wait_time += slept) {
 231                 struct timeval tv;
 232                 fd_set w_fds;
 233                 int ret;
 234                 int connect_errno = 0;
 235                 socklen_t errnosize;
 236
 237                 if (wait_time >= CONNECT_TIMEOUT)
 238                         goto error_out;
 239
 240                 switch (errno) {
 241                         case EINPROGRESS:
 242                                 FD_ZERO(&w_fds);
 243                                 FD_SET(fd, &w_fds);
 244                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 245                                 tv.tv_usec = 0;
 246
 247                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 248
 249                                 if (ret > 0) {
 250                                         errnosize = sizeof(connect_errno);
 251
 252                                         ret = getsockopt(fd, SOL_SOCKET,
 253                                                         SO_ERROR, &connect_errno, &errnosize);
 254
 255                                         if (ret >= 0 && connect_errno == 0) {
 256                                                 /* Connect succeed */
 257                                                 goto out;
 258                                         }
 259                                 }
 260
 261                                 slept = CONNECT_TIMEOUT;
 262                                 break;
 263                         case EAGAIN:
 264                                 slept = rand() % 3 + 1;
 265                                 sleep(slept);
 266                                 break;
 267                         default:
 268                                 goto error_out;
 269                 }
 270
 271         }
 272
 273   out:
 274
 275         return fd;
 276
 277   error_out:
 278
 279         close(fd);
 280         return -1;
 281 }
 282
 283 static const char *winbindd_socket_dir(void)
 284 {
 285 #ifdef SOCKET_WRAPPER
 286         const char *env_dir;
 287
 288         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 289         if (env_dir) {
 290                 return env_dir;
 291         }
 292 #endif
 293
 294         return WINBINDD_SOCKET_DIR;
 295 }
 296
 297 /* Connect to winbindd socket */
 298
 299 static int winbind_open_pipe_sock(int recursing, int need_priv)
 300 {
 301 #ifdef HAVE_UNIXSOCKET
 302         static pid_t our_pid;
 303         struct winbindd_request request;
 304         struct winbindd_response response;
 305         ZERO_STRUCT(request);
 306         ZERO_STRUCT(response);
 307
 308         if (our_pid != getpid()) {
 309                 winbind_close_sock();
 310                 our_pid = getpid();
 311         }
 312
 313         if ((need_priv != 0) && (is_privileged == 0)) {
 314                 winbind_close_sock();
 315         }
 316
 317         if (winbindd_fd != -1) {
 318                 return winbindd_fd;
 319         }
 320
 321         if (recursing) {
 322                 return -1;
 323         }
 324
 325         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 326                 return -1;
 327         }
 328
 329         is_privileged = 0;
 330
 331         /* version-check the socket */
 332
 333         request.wb_flags = WBFLAG_RECURSE;
 334         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 335                 winbind_close_sock();
 336                 return -1;
 337         }
 338
 339         /* try and get priv pipe */
 340
 341         request.wb_flags = WBFLAG_RECURSE;
 342         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 343                 int fd;
 344                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 345                         close(winbindd_fd);
 346                         winbindd_fd = fd;
 347                         is_privileged = 1;
 348                 }
 349         }
 350
 351         if ((need_priv != 0) && (is_privileged == 0)) {
 352                 return -1;
 353         }
 354
 355         SAFE_FREE(response.extra_data.data);
 356
 357         return winbindd_fd;
 358 #else
 359         return -1;
 360 #endif /* HAVE_UNIXSOCKET */
 361 }
 362
 363 /* Write data to winbindd socket */
 364
 365 int winbind_write_sock(void *buffer, int count, int recursing, int need_priv)
 366 {
 367         int result, nwritten;
 368
 369         /* Open connection to winbind daemon */
 370
 371  restart:
 372
 373         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 374                 return -1;
 375         }
 376
 377         /* Write data to socket */
 378
 379         nwritten = 0;
 380
 381         while(nwritten < count) {
 382                 struct timeval tv;
 383                 fd_set r_fds;
 384
 385                 /* Catch pipe close on other end by checking if a read()
 386                    call would not block by calling select(). */
 387
 388                 FD_ZERO(&r_fds);
 389                 FD_SET(winbindd_fd, &r_fds);
 390                 ZERO_STRUCT(tv);
 391
 392                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 393                         winbind_close_sock();
 394                         return -1;                   /* Select error */
 395                 }
 396
 397                 /* Write should be OK if fd not available for reading */
 398
 399                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 400
 401                         /* Do the write */
 402
 403                         result = write(winbindd_fd,
 404                                        (char *)buffer + nwritten,
 405                                        count - nwritten);
 406
 407                         if ((result == -1) || (result == 0)) {
 408
 409                                 /* Write failed */
 410
 411                                 winbind_close_sock();
 412                                 return -1;
 413                         }
 414
 415                         nwritten += result;
 416
 417                 } else {
 418
 419                         /* Pipe has closed on remote end */
 420
 421                         winbind_close_sock();
 422                         goto restart;
 423                 }
 424         }
 425
 426         return nwritten;
 427 }
 428
 429 /* Read data from winbindd socket */
 430
 431 int winbind_read_sock(void *buffer, int count)
 432 {
 433         int nread = 0;
 434         int total_time = 0, selret;
 435
 436         if (winbindd_fd == -1) {
 437                 return -1;
 438         }
 439
 440         /* Read data from socket */
 441         while(nread < count) {
 442                 struct timeval tv;
 443                 fd_set r_fds;
 444
 445                 /* Catch pipe close on other end by checking if a read()
 446                    call would not block by calling select(). */
 447
 448                 FD_ZERO(&r_fds);
 449                 FD_SET(winbindd_fd, &r_fds);
 450                 ZERO_STRUCT(tv);
 451                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 452                 tv.tv_sec = 5;
 453
 454                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 455                         winbind_close_sock();
 456                         return -1;                   /* Select error */
 457                 }
 458
 459                 if (selret == 0) {
 460                         /* Not ready for read yet... */
 461                         if (total_time >= 30) {
 462                                 /* Timeout */
 463                                 winbind_close_sock();
 464                                 return -1;
 465                         }
 466                         total_time += 5;
 467                         continue;
 468                 }
 469
 470                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 471
 472                         /* Do the Read */
 473
 474                         int result = read(winbindd_fd, (char *)buffer + nread,
 475                               count - nread);
 476
 477                         if ((result == -1) || (result == 0)) {
 478
 479                                 /* Read failed.  I think the only useful thing we
 480                                    can do here is just return -1 and fail since the
 481                                    transaction has failed half way through. */
 482
 483                                 winbind_close_sock();
 484                                 return -1;
 485                         }
 486
 487                         nread += result;
 488
 489                 }
 490         }
 491
 492         return nread;
 493 }
 494
 495 /* Read reply */
 496
 497 int winbindd_read_reply(struct winbindd_response *response)
 498 {
 499         int result1, result2 = 0;
 500
 501         if (!response) {
 502                 return -1;
 503         }
 504
 505         /* Read fixed length response */
 506
 507         result1 = winbind_read_sock(response,
 508                                     sizeof(struct winbindd_response));
 509         if (result1 == -1) {
 510                 return -1;
 511         }
 512
 513         /* We actually send the pointer value of the extra_data field from
 514            the server.  This has no meaning in the client's address space
 515            so we clear it out. */
 516
 517         response->extra_data.data = NULL;
 518
 519         /* Read variable length response */
 520
 521         if (response->length > sizeof(struct winbindd_response)) {
 522                 int extra_data_len = response->length -
 523                         sizeof(struct winbindd_response);
 524
 525                 /* Mallocate memory for extra data */
 526
 527                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 528                         return -1;
 529                 }
 530
 531                 result2 = winbind_read_sock(response->extra_data.data,
 532                                             extra_data_len);
 533                 if (result2 == -1) {
 534                         winbindd_free_response(response);
 535                         return -1;
 536                 }
 537         }
 538
 539         /* Return total amount of data read */
 540
 541         return result1 + result2;
 542 }
 543
 544 bool winbind_env_set(void)
 545 {
 546         char *env;
 547
 548         if ((env=getenv(WINBINDD_DONT_ENV)) != NULL) {
 549                 if(strcmp(env, "1") == 0) {
 550                         return true;
 551                 }
 552         }
 553         return false;
 554 }
 555
 556 /*
 557  * send simple types of requests
 558  */
 559
 560 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 561                                  struct winbindd_request *request)
 562 {
 563         struct winbindd_request lrequest;
 564
 565         /* Check for our tricky environment variable */
 566
 567         if (winbind_env_set()) {
 568                 return NSS_STATUS_NOTFOUND;
 569         }
 570
 571         if (!request) {
 572                 ZERO_STRUCT(lrequest);
 573                 request = &lrequest;
 574         }
 575
 576         /* Fill in request and send down pipe */
 577
 578         winbindd_init_request(request, req_type);
 579
 580         if (winbind_write_sock(request, sizeof(*request),
 581                                request->wb_flags & WBFLAG_RECURSE,
 582                                need_priv) == -1) {
 583                 return NSS_STATUS_UNAVAIL;
 584         }
 585
 586         if ((request->extra_len != 0) &&
 587             (winbind_write_sock(request->extra_data.data,
 588                                 request->extra_len,
 589                                 request->wb_flags & WBFLAG_RECURSE,
 590                                 need_priv) == -1)) {
 591                 return NSS_STATUS_UNAVAIL;
 592         }
 593
 594         return NSS_STATUS_SUCCESS;
 595 }
 596
 597 /*
 598  * Get results from winbindd request
 599  */
 600
 601 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 602 {
 603         struct winbindd_response lresponse;
 604
 605         if (!response) {
 606                 ZERO_STRUCT(lresponse);
 607                 response = &lresponse;
 608         }
 609
 610         init_response(response);
 611
 612         /* Wait for reply */
 613         if (winbindd_read_reply(response) == -1) {
 614                 return NSS_STATUS_UNAVAIL;
 615         }
 616
 617         /* Throw away extra data if client didn't request it */
 618         if (response == &lresponse) {
 619                 winbindd_free_response(response);
 620         }
 621
 622         /* Copy reply data from socket */
 623         if (response->result != WINBINDD_OK) {
 624                 return NSS_STATUS_NOTFOUND;
 625         }
 626
 627         return NSS_STATUS_SUCCESS;
 628 }
 629
 630 /* Handle simple types of requests */
 631
 632 NSS_STATUS winbindd_request_response(int req_type,
 633                             struct winbindd_request *request,
 634                             struct winbindd_response *response)
 635 {
 636         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 637         int count = 0;
 638
 639         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 640                 status = winbindd_send_request(req_type, 0, request);
 641                 if (status != NSS_STATUS_SUCCESS)
 642                         return(status);
 643                 status = winbindd_get_response(response);
 644                 count += 1;
 645         }
 646
 647         return status;
 648 }
 649
 650 NSS_STATUS winbindd_priv_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, 1, 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 /*************************************************************************
 669  A couple of simple functions to disable winbindd lookups and re-
 670  enable them
 671  ************************************************************************/
 672
 673 bool winbind_off(void)
 674 {
 675         return setenv(WINBINDD_DONT_ENV, "1", 1) != -1;
 676 }
 677
 678 bool winbind_on(void)
 679 {
 680         return setenv(WINBINDD_DONT_ENV, "0", 1) != -1;
 681 }
 682
 683 /*************************************************************************
 684  ************************************************************************/
 685
 686 const char *nss_err_str(NSS_STATUS ret)
 687 {
 688         switch (ret) {
 689                 case NSS_STATUS_TRYAGAIN:
 690                         return "NSS_STATUS_TRYAGAIN";
 691                 case NSS_STATUS_SUCCESS:
 692                         return "NSS_STATUS_SUCCESS";
 693                 case NSS_STATUS_NOTFOUND:
 694                         return "NSS_STATUS_NOTFOUND";
 695                 case NSS_STATUS_UNAVAIL:
 696                         return "NSS_STATUS_UNAVAIL";
 697 #ifdef NSS_STATUS_RETURN
 698                 case NSS_STATUS_RETURN:
 699                         return "NSS_STATUS_RETURN";
 700 #endif
 701                 default:
 702                         return "UNKNOWN RETURN CODE!!!!!!!";
 703         }
 704 }