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 static void winbindd_init_request(struct winbindd_request *request,
  45                                   int request_type)
  46 {
  47         request->length = sizeof(struct winbindd_request);
  48
  49         request->cmd = (enum winbindd_cmd)request_type;
  50         request->pid = getpid();
  51
  52 }
  53
  54 /* Initialise a response structure */
  55
  56 static void init_response(struct winbindd_response *response)
  57 {
  58         /* Initialise return value */
  59
  60         response->result = WINBINDD_ERROR;
  61 }
  62
  63 /* Close established socket */
  64
  65 #if HAVE_FUNCTION_ATTRIBUTE_DESTRUCTOR
  66 __attribute__((destructor))
  67 #endif
  68 static void winbind_close_sock(void)
  69 {
  70         if (winbindd_fd != -1) {
  71                 close(winbindd_fd);
  72                 winbindd_fd = -1;
  73         }
  74 }
  75
  76 #define CONNECT_TIMEOUT 30
  77
  78 /* Make sure socket handle isn't stdin, stdout or stderr */
  79 #define RECURSION_LIMIT 3
  80
  81 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  82 {
  83         int new_fd;
  84         if (fd >= 0 && fd <= 2) {
  85 #ifdef F_DUPFD
  86                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  87                         return -1;
  88                 }
  89                 /* Paranoia */
  90                 if (new_fd < 3) {
  91                         close(new_fd);
  92                         return -1;
  93                 }
  94                 close(fd);
  95                 return new_fd;
  96 #else
  97                 if (limit <= 0)
  98                         return -1;
  99
 100                 new_fd = dup(fd);
 101                 if (new_fd == -1)
 102                         return -1;
 103
 104                 /* use the program stack to hold our list of FDs to close */
 105                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 106                 close(fd);
 107                 return new_fd;
 108 #endif
 109         }
 110         return fd;
 111 }
 112
 113 /****************************************************************************
 114  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 115  else
 116  if SYSV use O_NDELAY
 117  if BSD use FNDELAY
 118  Set close on exec also.
 119 ****************************************************************************/
 120
 121 static int make_safe_fd(int fd)
 122 {
 123         int result, flags;
 124         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 125         if (new_fd == -1) {
 126                 close(fd);
 127                 return -1;
 128         }
 129
 130         /* Socket should be nonblocking. */
 131 #ifdef O_NONBLOCK
 132 #define FLAG_TO_SET O_NONBLOCK
 133 #else
 134 #ifdef SYSV
 135 #define FLAG_TO_SET O_NDELAY
 136 #else /* BSD */
 137 #define FLAG_TO_SET FNDELAY
 138 #endif
 139 #endif
 140
 141         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 142                 close(new_fd);
 143                 return -1;
 144         }
 145
 146         flags |= FLAG_TO_SET;
 147         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 148                 close(new_fd);
 149                 return -1;
 150         }
 151
 152 #undef FLAG_TO_SET
 153
 154         /* Socket should be closed on exec() */
 155 #ifdef FD_CLOEXEC
 156         result = flags = fcntl(new_fd, F_GETFD, 0);
 157         if (flags >= 0) {
 158                 flags |= FD_CLOEXEC;
 159                 result = fcntl( new_fd, F_SETFD, flags );
 160         }
 161         if (result < 0) {
 162                 close(new_fd);
 163                 return -1;
 164         }
 165 #endif
 166         return new_fd;
 167 }
 168
 169 /* Connect to winbindd socket */
 170
 171 static int winbind_named_pipe_sock(const char *dir)
 172 {
 173         struct sockaddr_un sunaddr;
 174         struct stat st;
 175         char *path = NULL;
 176         int fd;
 177         int wait_time;
 178         int slept;
 179
 180         /* Check permissions on unix socket directory */
 181
 182         if (lstat(dir, &st) == -1) {
 183                 errno = ENOENT;
 184                 return -1;
 185         }
 186
 187         if (!S_ISDIR(st.st_mode) ||
 188             (st.st_uid != 0 && st.st_uid != geteuid())) {
 189                 errno = ENOENT;
 190                 return -1;
 191         }
 192
 193         /* Connect to socket */
 194
 195         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 196                 return -1;
 197         }
 198
 199         ZERO_STRUCT(sunaddr);
 200         sunaddr.sun_family = AF_UNIX;
 201         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 202
 203         /* If socket file doesn't exist, don't bother trying to connect
 204            with retry.  This is an attempt to make the system usable when
 205            the winbindd daemon is not running. */
 206
 207         if (lstat(path, &st) == -1) {
 208                 errno = ENOENT;
 209                 SAFE_FREE(path);
 210                 return -1;
 211         }
 212
 213         SAFE_FREE(path);
 214         /* Check permissions on unix socket file */
 215
 216         if (!S_ISSOCK(st.st_mode) ||
 217             (st.st_uid != 0 && st.st_uid != geteuid())) {
 218                 errno = ENOENT;
 219                 return -1;
 220         }
 221
 222         /* Connect to socket */
 223
 224         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 225                 return -1;
 226         }
 227
 228         /* Set socket non-blocking and close on exec. */
 229
 230         if ((fd = make_safe_fd( fd)) == -1) {
 231                 return fd;
 232         }
 233
 234         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 235                         wait_time += slept) {
 236                 struct timeval tv;
 237                 fd_set w_fds;
 238                 int ret;
 239                 int connect_errno = 0;
 240                 socklen_t errnosize;
 241
 242                 if (wait_time >= CONNECT_TIMEOUT)
 243                         goto error_out;
 244
 245                 switch (errno) {
 246                         case EINPROGRESS:
 247                                 FD_ZERO(&w_fds);
 248                                 FD_SET(fd, &w_fds);
 249                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 250                                 tv.tv_usec = 0;
 251
 252                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 253
 254                                 if (ret > 0) {
 255                                         errnosize = sizeof(connect_errno);
 256
 257                                         ret = getsockopt(fd, SOL_SOCKET,
 258                                                         SO_ERROR, &connect_errno, &errnosize);
 259
 260                                         if (ret >= 0 && connect_errno == 0) {
 261                                                 /* Connect succeed */
 262                                                 goto out;
 263                                         }
 264                                 }
 265
 266                                 slept = CONNECT_TIMEOUT;
 267                                 break;
 268                         case EAGAIN:
 269                                 slept = rand() % 3 + 1;
 270                                 sleep(slept);
 271                                 break;
 272                         default:
 273                                 goto error_out;
 274                 }
 275
 276         }
 277
 278   out:
 279
 280         return fd;
 281
 282   error_out:
 283
 284         close(fd);
 285         return -1;
 286 }
 287
 288 static const char *winbindd_socket_dir(void)
 289 {
 290 #ifdef SOCKET_WRAPPER
 291         const char *env_dir;
 292
 293         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 294         if (env_dir) {
 295                 return env_dir;
 296         }
 297 #endif
 298
 299         return WINBINDD_SOCKET_DIR;
 300 }
 301
 302 /* Connect to winbindd socket */
 303
 304 static int winbind_open_pipe_sock(int recursing, int need_priv)
 305 {
 306 #ifdef HAVE_UNIXSOCKET
 307         static pid_t our_pid;
 308         struct winbindd_request request;
 309         struct winbindd_response response;
 310         ZERO_STRUCT(request);
 311         ZERO_STRUCT(response);
 312
 313         if (our_pid != getpid()) {
 314                 winbind_close_sock();
 315                 our_pid = getpid();
 316         }
 317
 318         if ((need_priv != 0) && (is_privileged == 0)) {
 319                 winbind_close_sock();
 320         }
 321
 322         if (winbindd_fd != -1) {
 323                 return winbindd_fd;
 324         }
 325
 326         if (recursing) {
 327                 return -1;
 328         }
 329
 330         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 331                 return -1;
 332         }
 333
 334         is_privileged = 0;
 335
 336         /* version-check the socket */
 337
 338         request.wb_flags = WBFLAG_RECURSE;
 339         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 340                 winbind_close_sock();
 341                 return -1;
 342         }
 343
 344         /* try and get priv pipe */
 345
 346         request.wb_flags = WBFLAG_RECURSE;
 347         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 348                 int fd;
 349                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 350                         close(winbindd_fd);
 351                         winbindd_fd = fd;
 352                         is_privileged = 1;
 353                 }
 354         }
 355
 356         if ((need_priv != 0) && (is_privileged == 0)) {
 357                 return -1;
 358         }
 359
 360         SAFE_FREE(response.extra_data.data);
 361
 362         return winbindd_fd;
 363 #else
 364         return -1;
 365 #endif /* HAVE_UNIXSOCKET */
 366 }
 367
 368 /* Write data to winbindd socket */
 369
 370 static int winbind_write_sock(void *buffer, int count, int recursing,
 371                               int need_priv)
 372 {
 373         int result, nwritten;
 374
 375         /* Open connection to winbind daemon */
 376
 377  restart:
 378
 379         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 380                 errno = ENOENT;
 381                 return -1;
 382         }
 383
 384         /* Write data to socket */
 385
 386         nwritten = 0;
 387
 388         while(nwritten < count) {
 389                 struct timeval tv;
 390                 fd_set r_fds;
 391
 392                 /* Catch pipe close on other end by checking if a read()
 393                    call would not block by calling select(). */
 394
 395                 FD_ZERO(&r_fds);
 396                 FD_SET(winbindd_fd, &r_fds);
 397                 ZERO_STRUCT(tv);
 398
 399                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 400                         winbind_close_sock();
 401                         return -1;                   /* Select error */
 402                 }
 403
 404                 /* Write should be OK if fd not available for reading */
 405
 406                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 407
 408                         /* Do the write */
 409
 410                         result = write(winbindd_fd,
 411                                        (char *)buffer + nwritten,
 412                                        count - nwritten);
 413
 414                         if ((result == -1) || (result == 0)) {
 415
 416                                 /* Write failed */
 417
 418                                 winbind_close_sock();
 419                                 return -1;
 420                         }
 421
 422                         nwritten += result;
 423
 424                 } else {
 425
 426                         /* Pipe has closed on remote end */
 427
 428                         winbind_close_sock();
 429                         goto restart;
 430                 }
 431         }
 432
 433         return nwritten;
 434 }
 435
 436 /* Read data from winbindd socket */
 437
 438 static int winbind_read_sock(void *buffer, int count)
 439 {
 440         int nread = 0;
 441         int total_time = 0, selret;
 442
 443         if (winbindd_fd == -1) {
 444                 return -1;
 445         }
 446
 447         /* Read data from socket */
 448         while(nread < count) {
 449                 struct timeval tv;
 450                 fd_set r_fds;
 451
 452                 /* Catch pipe close on other end by checking if a read()
 453                    call would not block by calling select(). */
 454
 455                 FD_ZERO(&r_fds);
 456                 FD_SET(winbindd_fd, &r_fds);
 457                 ZERO_STRUCT(tv);
 458                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 459                 tv.tv_sec = 5;
 460
 461                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 462                         winbind_close_sock();
 463                         return -1;                   /* Select error */
 464                 }
 465
 466                 if (selret == 0) {
 467                         /* Not ready for read yet... */
 468                         if (total_time >= 30) {
 469                                 /* Timeout */
 470                                 winbind_close_sock();
 471                                 return -1;
 472                         }
 473                         total_time += 5;
 474                         continue;
 475                 }
 476
 477                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 478
 479                         /* Do the Read */
 480
 481                         int result = read(winbindd_fd, (char *)buffer + nread,
 482                               count - nread);
 483
 484                         if ((result == -1) || (result == 0)) {
 485
 486                                 /* Read failed.  I think the only useful thing we
 487                                    can do here is just return -1 and fail since the
 488                                    transaction has failed half way through. */
 489
 490                                 winbind_close_sock();
 491                                 return -1;
 492                         }
 493
 494                         nread += result;
 495
 496                 }
 497         }
 498
 499         return nread;
 500 }
 501
 502 /* Read reply */
 503
 504 static int winbindd_read_reply(struct winbindd_response *response)
 505 {
 506         int result1, result2 = 0;
 507
 508         if (!response) {
 509                 return -1;
 510         }
 511
 512         /* Read fixed length response */
 513
 514         result1 = winbind_read_sock(response,
 515                                     sizeof(struct winbindd_response));
 516         if (result1 == -1) {
 517                 return -1;
 518         }
 519
 520         /* We actually send the pointer value of the extra_data field from
 521            the server.  This has no meaning in the client's address space
 522            so we clear it out. */
 523
 524         response->extra_data.data = NULL;
 525
 526         /* Read variable length response */
 527
 528         if (response->length > sizeof(struct winbindd_response)) {
 529                 int extra_data_len = response->length -
 530                         sizeof(struct winbindd_response);
 531
 532                 /* Mallocate memory for extra data */
 533
 534                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 535                         return -1;
 536                 }
 537
 538                 result2 = winbind_read_sock(response->extra_data.data,
 539                                             extra_data_len);
 540                 if (result2 == -1) {
 541                         winbindd_free_response(response);
 542                         return -1;
 543                 }
 544         }
 545
 546         /* Return total amount of data read */
 547
 548         return result1 + result2;
 549 }
 550
 551 /*
 552  * send simple types of requests
 553  */
 554
 555 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 556                                  struct winbindd_request *request)
 557 {
 558         struct winbindd_request lrequest;
 559
 560         /* Check for our tricky environment variable */
 561
 562         if (winbind_env_set()) {
 563                 return NSS_STATUS_NOTFOUND;
 564         }
 565
 566         if (!request) {
 567                 ZERO_STRUCT(lrequest);
 568                 request = &lrequest;
 569         }
 570
 571         /* Fill in request and send down pipe */
 572
 573         winbindd_init_request(request, req_type);
 574
 575         if (winbind_write_sock(request, sizeof(*request),
 576                                request->wb_flags & WBFLAG_RECURSE,
 577                                need_priv) == -1)
 578         {
 579                 /* Set ENOENT for consistency.  Required by some apps */
 580                 errno = ENOENT;
 581
 582                 return NSS_STATUS_UNAVAIL;
 583         }
 584
 585         if ((request->extra_len != 0) &&
 586             (winbind_write_sock(request->extra_data.data,
 587                                 request->extra_len,
 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         return NSS_STATUS_SUCCESS;
 598 }
 599
 600 /*
 601  * Get results from winbindd request
 602  */
 603
 604 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 605 {
 606         struct winbindd_response lresponse;
 607
 608         if (!response) {
 609                 ZERO_STRUCT(lresponse);
 610                 response = &lresponse;
 611         }
 612
 613         init_response(response);
 614
 615         /* Wait for reply */
 616         if (winbindd_read_reply(response) == -1) {
 617                 /* Set ENOENT for consistency.  Required by some apps */
 618                 errno = ENOENT;
 619
 620                 return NSS_STATUS_UNAVAIL;
 621         }
 622
 623         /* Throw away extra data if client didn't request it */
 624         if (response == &lresponse) {
 625                 winbindd_free_response(response);
 626         }
 627
 628         /* Copy reply data from socket */
 629         if (response->result != WINBINDD_OK) {
 630                 return NSS_STATUS_NOTFOUND;
 631         }
 632
 633         return NSS_STATUS_SUCCESS;
 634 }
 635
 636 /* Handle simple types of requests */
 637
 638 NSS_STATUS winbindd_request_response(int req_type,
 639                             struct winbindd_request *request,
 640                             struct winbindd_response *response)
 641 {
 642         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 643         int count = 0;
 644
 645         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 646                 status = winbindd_send_request(req_type, 0, request);
 647                 if (status != NSS_STATUS_SUCCESS)
 648                         return(status);
 649                 status = winbindd_get_response(response);
 650                 count += 1;
 651         }
 652
 653         return status;
 654 }
 655
 656 NSS_STATUS winbindd_priv_request_response(int req_type,
 657                                           struct winbindd_request *request,
 658                                           struct winbindd_response *response)
 659 {
 660         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 661         int count = 0;
 662
 663         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 664                 status = winbindd_send_request(req_type, 1, request);
 665                 if (status != NSS_STATUS_SUCCESS)
 666                         return(status);
 667                 status = winbindd_get_response(response);
 668                 count += 1;
 669         }
 670
 671         return status;
 672 }