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         char *path = NULL;
 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                 errno = ENOENT;
 180                 return -1;
 181         }
 182
 183         if (!S_ISDIR(st.st_mode) ||
 184             (st.st_uid != 0 && st.st_uid != geteuid())) {
 185                 errno = ENOENT;
 186                 return -1;
 187         }
 188
 189         /* Connect to socket */
 190
 191         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 192                 return -1;
 193         }
 194
 195         ZERO_STRUCT(sunaddr);
 196         sunaddr.sun_family = AF_UNIX;
 197         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 198
 199         /* If socket file doesn't exist, don't bother trying to connect
 200            with retry.  This is an attempt to make the system usable when
 201            the winbindd daemon is not running. */
 202
 203         if (lstat(path, &st) == -1) {
 204                 errno = ENOENT;
 205                 SAFE_FREE(path);
 206                 return -1;
 207         }
 208
 209         SAFE_FREE(path);
 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                 errno = ENOENT;
 215                 return -1;
 216         }
 217
 218         /* Connect to socket */
 219
 220         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 221                 return -1;
 222         }
 223
 224         /* Set socket non-blocking and close on exec. */
 225
 226         if ((fd = make_safe_fd( fd)) == -1) {
 227                 return fd;
 228         }
 229
 230         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 231                         wait_time += slept) {
 232                 struct timeval tv;
 233                 fd_set w_fds;
 234                 int ret;
 235                 int connect_errno = 0;
 236                 socklen_t errnosize;
 237
 238                 if (wait_time >= CONNECT_TIMEOUT)
 239                         goto error_out;
 240
 241                 switch (errno) {
 242                         case EINPROGRESS:
 243                                 FD_ZERO(&w_fds);
 244                                 FD_SET(fd, &w_fds);
 245                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 246                                 tv.tv_usec = 0;
 247
 248                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 249
 250                                 if (ret > 0) {
 251                                         errnosize = sizeof(connect_errno);
 252
 253                                         ret = getsockopt(fd, SOL_SOCKET,
 254                                                         SO_ERROR, &connect_errno, &errnosize);
 255
 256                                         if (ret >= 0 && connect_errno == 0) {
 257                                                 /* Connect succeed */
 258                                                 goto out;
 259                                         }
 260                                 }
 261
 262                                 slept = CONNECT_TIMEOUT;
 263                                 break;
 264                         case EAGAIN:
 265                                 slept = rand() % 3 + 1;
 266                                 sleep(slept);
 267                                 break;
 268                         default:
 269                                 goto error_out;
 270                 }
 271
 272         }
 273
 274   out:
 275
 276         return fd;
 277
 278   error_out:
 279
 280         close(fd);
 281         return -1;
 282 }
 283
 284 static const char *winbindd_socket_dir(void)
 285 {
 286 #ifdef SOCKET_WRAPPER
 287         const char *env_dir;
 288
 289         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 290         if (env_dir) {
 291                 return env_dir;
 292         }
 293 #endif
 294
 295         return WINBINDD_SOCKET_DIR;
 296 }
 297
 298 /* Connect to winbindd socket */
 299
 300 static int winbind_open_pipe_sock(int recursing, int need_priv)
 301 {
 302 #ifdef HAVE_UNIXSOCKET
 303         static pid_t our_pid;
 304         struct winbindd_request request;
 305         struct winbindd_response response;
 306         ZERO_STRUCT(request);
 307         ZERO_STRUCT(response);
 308
 309         if (our_pid != getpid()) {
 310                 winbind_close_sock();
 311                 our_pid = getpid();
 312         }
 313
 314         if ((need_priv != 0) && (is_privileged == 0)) {
 315                 winbind_close_sock();
 316         }
 317
 318         if (winbindd_fd != -1) {
 319                 return winbindd_fd;
 320         }
 321
 322         if (recursing) {
 323                 return -1;
 324         }
 325
 326         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 327                 return -1;
 328         }
 329
 330         is_privileged = 0;
 331
 332         /* version-check the socket */
 333
 334         request.wb_flags = WBFLAG_RECURSE;
 335         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 336                 winbind_close_sock();
 337                 return -1;
 338         }
 339
 340         /* try and get priv pipe */
 341
 342         request.wb_flags = WBFLAG_RECURSE;
 343         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 344                 int fd;
 345                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 346                         close(winbindd_fd);
 347                         winbindd_fd = fd;
 348                         is_privileged = 1;
 349                 }
 350         }
 351
 352         if ((need_priv != 0) && (is_privileged == 0)) {
 353                 return -1;
 354         }
 355
 356         SAFE_FREE(response.extra_data.data);
 357
 358         return winbindd_fd;
 359 #else
 360         return -1;
 361 #endif /* HAVE_UNIXSOCKET */
 362 }
 363
 364 /* Write data to winbindd socket */
 365
 366 int winbind_write_sock(void *buffer, int count, int recursing, int need_priv)
 367 {
 368         int result, nwritten;
 369
 370         /* Open connection to winbind daemon */
 371
 372  restart:
 373
 374         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 375                 errno = ENOENT;
 376                 return -1;
 377         }
 378
 379         /* Write data to socket */
 380
 381         nwritten = 0;
 382
 383         while(nwritten < count) {
 384                 struct timeval tv;
 385                 fd_set r_fds;
 386
 387                 /* Catch pipe close on other end by checking if a read()
 388                    call would not block by calling select(). */
 389
 390                 FD_ZERO(&r_fds);
 391                 FD_SET(winbindd_fd, &r_fds);
 392                 ZERO_STRUCT(tv);
 393
 394                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 395                         winbind_close_sock();
 396                         return -1;                   /* Select error */
 397                 }
 398
 399                 /* Write should be OK if fd not available for reading */
 400
 401                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 402
 403                         /* Do the write */
 404
 405                         result = write(winbindd_fd,
 406                                        (char *)buffer + nwritten,
 407                                        count - nwritten);
 408
 409                         if ((result == -1) || (result == 0)) {
 410
 411                                 /* Write failed */
 412
 413                                 winbind_close_sock();
 414                                 return -1;
 415                         }
 416
 417                         nwritten += result;
 418
 419                 } else {
 420
 421                         /* Pipe has closed on remote end */
 422
 423                         winbind_close_sock();
 424                         goto restart;
 425                 }
 426         }
 427
 428         return nwritten;
 429 }
 430
 431 /* Read data from winbindd socket */
 432
 433 int winbind_read_sock(void *buffer, int count)
 434 {
 435         int nread = 0;
 436         int total_time = 0, selret;
 437
 438         if (winbindd_fd == -1) {
 439                 return -1;
 440         }
 441
 442         /* Read data from socket */
 443         while(nread < count) {
 444                 struct timeval tv;
 445                 fd_set r_fds;
 446
 447                 /* Catch pipe close on other end by checking if a read()
 448                    call would not block by calling select(). */
 449
 450                 FD_ZERO(&r_fds);
 451                 FD_SET(winbindd_fd, &r_fds);
 452                 ZERO_STRUCT(tv);
 453                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 454                 tv.tv_sec = 5;
 455
 456                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 457                         winbind_close_sock();
 458                         return -1;                   /* Select error */
 459                 }
 460
 461                 if (selret == 0) {
 462                         /* Not ready for read yet... */
 463                         if (total_time >= 30) {
 464                                 /* Timeout */
 465                                 winbind_close_sock();
 466                                 return -1;
 467                         }
 468                         total_time += 5;
 469                         continue;
 470                 }
 471
 472                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 473
 474                         /* Do the Read */
 475
 476                         int result = read(winbindd_fd, (char *)buffer + nread,
 477                               count - nread);
 478
 479                         if ((result == -1) || (result == 0)) {
 480
 481                                 /* Read failed.  I think the only useful thing we
 482                                    can do here is just return -1 and fail since the
 483                                    transaction has failed half way through. */
 484
 485                                 winbind_close_sock();
 486                                 return -1;
 487                         }
 488
 489                         nread += result;
 490
 491                 }
 492         }
 493
 494         return nread;
 495 }
 496
 497 /* Read reply */
 498
 499 int winbindd_read_reply(struct winbindd_response *response)
 500 {
 501         int result1, result2 = 0;
 502
 503         if (!response) {
 504                 return -1;
 505         }
 506
 507         /* Read fixed length response */
 508
 509         result1 = winbind_read_sock(response,
 510                                     sizeof(struct winbindd_response));
 511         if (result1 == -1) {
 512                 return -1;
 513         }
 514
 515         /* We actually send the pointer value of the extra_data field from
 516            the server.  This has no meaning in the client's address space
 517            so we clear it out. */
 518
 519         response->extra_data.data = NULL;
 520
 521         /* Read variable length response */
 522
 523         if (response->length > sizeof(struct winbindd_response)) {
 524                 int extra_data_len = response->length -
 525                         sizeof(struct winbindd_response);
 526
 527                 /* Mallocate memory for extra data */
 528
 529                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 530                         return -1;
 531                 }
 532
 533                 result2 = winbind_read_sock(response->extra_data.data,
 534                                             extra_data_len);
 535                 if (result2 == -1) {
 536                         winbindd_free_response(response);
 537                         return -1;
 538                 }
 539         }
 540
 541         /* Return total amount of data read */
 542
 543         return result1 + result2;
 544 }
 545
 546 /*
 547  * send simple types of requests
 548  */
 549
 550 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 551                                  struct winbindd_request *request)
 552 {
 553         struct winbindd_request lrequest;
 554
 555         /* Check for our tricky environment variable */
 556
 557         if (winbind_env_set()) {
 558                 return NSS_STATUS_NOTFOUND;
 559         }
 560
 561         if (!request) {
 562                 ZERO_STRUCT(lrequest);
 563                 request = &lrequest;
 564         }
 565
 566         /* Fill in request and send down pipe */
 567
 568         winbindd_init_request(request, req_type);
 569
 570         if (winbind_write_sock(request, sizeof(*request),
 571                                request->wb_flags & WBFLAG_RECURSE,
 572                                need_priv) == -1)
 573         {
 574                 /* Set ENOENT for consistency.  Required by some apps */
 575                 errno = ENOENT;
 576
 577                 return NSS_STATUS_UNAVAIL;
 578         }
 579
 580         if ((request->extra_len != 0) &&
 581             (winbind_write_sock(request->extra_data.data,
 582                                 request->extra_len,
 583                                 request->wb_flags & WBFLAG_RECURSE,
 584                                 need_priv) == -1))
 585         {
 586                 /* Set ENOENT for consistency.  Required by some apps */
 587                 errno = ENOENT;
 588
 589                 return NSS_STATUS_UNAVAIL;
 590         }
 591
 592         return NSS_STATUS_SUCCESS;
 593 }
 594
 595 /*
 596  * Get results from winbindd request
 597  */
 598
 599 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 600 {
 601         struct winbindd_response lresponse;
 602
 603         if (!response) {
 604                 ZERO_STRUCT(lresponse);
 605                 response = &lresponse;
 606         }
 607
 608         init_response(response);
 609
 610         /* Wait for reply */
 611         if (winbindd_read_reply(response) == -1) {
 612                 /* Set ENOENT for consistency.  Required by some apps */
 613                 errno = ENOENT;
 614
 615                 return NSS_STATUS_UNAVAIL;
 616         }
 617
 618         /* Throw away extra data if client didn't request it */
 619         if (response == &lresponse) {
 620                 winbindd_free_response(response);
 621         }
 622
 623         /* Copy reply data from socket */
 624         if (response->result != WINBINDD_OK) {
 625                 return NSS_STATUS_NOTFOUND;
 626         }
 627
 628         return NSS_STATUS_SUCCESS;
 629 }
 630
 631 /* Handle simple types of requests */
 632
 633 NSS_STATUS winbindd_request_response(int req_type,
 634                             struct winbindd_request *request,
 635                             struct winbindd_response *response)
 636 {
 637         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 638         int count = 0;
 639
 640         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 641                 status = winbindd_send_request(req_type, 0, request);
 642                 if (status != NSS_STATUS_SUCCESS)
 643                         return(status);
 644                 status = winbindd_get_response(response);
 645                 count += 1;
 646         }
 647
 648         return status;
 649 }
 650
 651 NSS_STATUS winbindd_priv_request_response(int req_type,
 652                                           struct winbindd_request *request,
 653                                           struct winbindd_response *response)
 654 {
 655         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 656         int count = 0;
 657
 658         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 659                 status = winbindd_send_request(req_type, 1, request);
 660                 if (status != NSS_STATUS_SUCCESS)
 661                         return(status);
 662                 status = winbindd_get_response(response);
 663                 count += 1;
 664         }
 665
 666         return status;
 667 }
 668
 669 /*************************************************************************
 670  ************************************************************************/
 671
 672 const char *nss_err_str(NSS_STATUS ret)
 673 {
 674         switch (ret) {
 675                 case NSS_STATUS_TRYAGAIN:
 676                         return "NSS_STATUS_TRYAGAIN";
 677                 case NSS_STATUS_SUCCESS:
 678                         return "NSS_STATUS_SUCCESS";
 679                 case NSS_STATUS_NOTFOUND:
 680                         return "NSS_STATUS_NOTFOUND";
 681                 case NSS_STATUS_UNAVAIL:
 682                         return "NSS_STATUS_UNAVAIL";
 683 #ifdef NSS_STATUS_RETURN
 684                 case NSS_STATUS_RETURN:
 685                         return "NSS_STATUS_RETURN";
 686 #endif
 687                 default:
 688                         return "UNKNOWN RETURN CODE!!!!!!!";
 689         }
 690 }