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 "replace.h"
  26 #include "system/select.h"
  27 #include "winbind_client.h"
  28
  29 /* Global variables.  These are effectively the client state information */
  30
  31 int winbindd_fd = -1;           /* fd for winbindd socket */
  32 static int is_privileged = 0;
  33
  34 /* Free a response structure */
  35
  36 void winbindd_free_response(struct winbindd_response *response)
  37 {
  38         /* Free any allocated extra_data */
  39
  40         if (response)
  41                 SAFE_FREE(response->extra_data.data);
  42 }
  43
  44 /* Initialise a request structure */
  45
  46 static void winbindd_init_request(struct winbindd_request *request,
  47                                   int request_type)
  48 {
  49         request->length = sizeof(struct winbindd_request);
  50
  51         request->cmd = (enum winbindd_cmd)request_type;
  52         request->pid = getpid();
  53
  54 }
  55
  56 /* Initialise a response structure */
  57
  58 static void init_response(struct winbindd_response *response)
  59 {
  60         /* Initialise return value */
  61
  62         response->result = WINBINDD_ERROR;
  63 }
  64
  65 /* Close established socket */
  66
  67 #if HAVE_FUNCTION_ATTRIBUTE_DESTRUCTOR
  68 __attribute__((destructor))
  69 #endif
  70 static void winbind_close_sock(void)
  71 {
  72         if (winbindd_fd != -1) {
  73                 close(winbindd_fd);
  74                 winbindd_fd = -1;
  75         }
  76 }
  77
  78 #define CONNECT_TIMEOUT 30
  79
  80 /* Make sure socket handle isn't stdin, stdout or stderr */
  81 #define RECURSION_LIMIT 3
  82
  83 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  84 {
  85         int new_fd;
  86         if (fd >= 0 && fd <= 2) {
  87 #ifdef F_DUPFD
  88                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  89                         return -1;
  90                 }
  91                 /* Paranoia */
  92                 if (new_fd < 3) {
  93                         close(new_fd);
  94                         return -1;
  95                 }
  96                 close(fd);
  97                 return new_fd;
  98 #else
  99                 if (limit <= 0)
 100                         return -1;
 101
 102                 new_fd = dup(fd);
 103                 if (new_fd == -1)
 104                         return -1;
 105
 106                 /* use the program stack to hold our list of FDs to close */
 107                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 108                 close(fd);
 109                 return new_fd;
 110 #endif
 111         }
 112         return fd;
 113 }
 114
 115 /****************************************************************************
 116  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 117  else
 118  if SYSV use O_NDELAY
 119  if BSD use FNDELAY
 120  Set close on exec also.
 121 ****************************************************************************/
 122
 123 static int make_safe_fd(int fd)
 124 {
 125         int result, flags;
 126         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 127         if (new_fd == -1) {
 128                 close(fd);
 129                 return -1;
 130         }
 131
 132         /* Socket should be nonblocking. */
 133 #ifdef O_NONBLOCK
 134 #define FLAG_TO_SET O_NONBLOCK
 135 #else
 136 #ifdef SYSV
 137 #define FLAG_TO_SET O_NDELAY
 138 #else /* BSD */
 139 #define FLAG_TO_SET FNDELAY
 140 #endif
 141 #endif
 142
 143         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 144                 close(new_fd);
 145                 return -1;
 146         }
 147
 148         flags |= FLAG_TO_SET;
 149         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 150                 close(new_fd);
 151                 return -1;
 152         }
 153
 154 #undef FLAG_TO_SET
 155
 156         /* Socket should be closed on exec() */
 157 #ifdef FD_CLOEXEC
 158         result = flags = fcntl(new_fd, F_GETFD, 0);
 159         if (flags >= 0) {
 160                 flags |= FD_CLOEXEC;
 161                 result = fcntl( new_fd, F_SETFD, flags );
 162         }
 163         if (result < 0) {
 164                 close(new_fd);
 165                 return -1;
 166         }
 167 #endif
 168         return new_fd;
 169 }
 170
 171 /* Connect to winbindd socket */
 172
 173 static int winbind_named_pipe_sock(const char *dir)
 174 {
 175         struct sockaddr_un sunaddr;
 176         struct stat st;
 177         char *path = NULL;
 178         int fd;
 179         int wait_time;
 180         int slept;
 181
 182         /* Check permissions on unix socket directory */
 183
 184         if (lstat(dir, &st) == -1) {
 185                 errno = ENOENT;
 186                 return -1;
 187         }
 188
 189         if (!S_ISDIR(st.st_mode) ||
 190             (st.st_uid != 0 && st.st_uid != geteuid())) {
 191                 errno = ENOENT;
 192                 return -1;
 193         }
 194
 195         /* Connect to socket */
 196
 197         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 198                 return -1;
 199         }
 200
 201         ZERO_STRUCT(sunaddr);
 202         sunaddr.sun_family = AF_UNIX;
 203         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 204
 205         /* If socket file doesn't exist, don't bother trying to connect
 206            with retry.  This is an attempt to make the system usable when
 207            the winbindd daemon is not running. */
 208
 209         if (lstat(path, &st) == -1) {
 210                 errno = ENOENT;
 211                 SAFE_FREE(path);
 212                 return -1;
 213         }
 214
 215         SAFE_FREE(path);
 216         /* Check permissions on unix socket file */
 217
 218         if (!S_ISSOCK(st.st_mode) ||
 219             (st.st_uid != 0 && st.st_uid != geteuid())) {
 220                 errno = ENOENT;
 221                 return -1;
 222         }
 223
 224         /* Connect to socket */
 225
 226         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 227                 return -1;
 228         }
 229
 230         /* Set socket non-blocking and close on exec. */
 231
 232         if ((fd = make_safe_fd( fd)) == -1) {
 233                 return fd;
 234         }
 235
 236         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 237                         wait_time += slept) {
 238                 struct pollfd pfd;
 239                 int ret;
 240                 int connect_errno = 0;
 241                 socklen_t errnosize;
 242
 243                 if (wait_time >= CONNECT_TIMEOUT)
 244                         goto error_out;
 245
 246                 switch (errno) {
 247                         case EINPROGRESS:
 248                                 pfd.fd = fd;
 249                                 pfd.events = POLLOUT;
 250
 251                                 ret = poll(&pfd, 1, (CONNECT_TIMEOUT - wait_time) * 1000);
 252
 253                                 if (ret > 0) {
 254                                         errnosize = sizeof(connect_errno);
 255
 256                                         ret = getsockopt(fd, SOL_SOCKET,
 257                                                         SO_ERROR, &connect_errno, &errnosize);
 258
 259                                         if (ret >= 0 && connect_errno == 0) {
 260                                                 /* Connect succeed */
 261                                                 goto out;
 262                                         }
 263                                 }
 264
 265                                 slept = CONNECT_TIMEOUT;
 266                                 break;
 267                         case EAGAIN:
 268                                 slept = rand() % 3 + 1;
 269                                 sleep(slept);
 270                                 break;
 271                         default:
 272                                 goto error_out;
 273                 }
 274
 275         }
 276
 277   out:
 278
 279         return fd;
 280
 281   error_out:
 282
 283         close(fd);
 284         return -1;
 285 }
 286
 287 static const char *winbindd_socket_dir(void)
 288 {
 289 #ifdef SOCKET_WRAPPER
 290         const char *env_dir;
 291
 292         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 293         if (env_dir) {
 294                 return env_dir;
 295         }
 296 #endif
 297
 298         return WINBINDD_SOCKET_DIR;
 299 }
 300
 301 /* Connect to winbindd socket */
 302
 303 static int winbind_open_pipe_sock(int recursing, int need_priv)
 304 {
 305 #ifdef HAVE_UNIXSOCKET
 306         static pid_t our_pid;
 307         struct winbindd_request request;
 308         struct winbindd_response response;
 309         ZERO_STRUCT(request);
 310         ZERO_STRUCT(response);
 311
 312         if (our_pid != getpid()) {
 313                 winbind_close_sock();
 314                 our_pid = getpid();
 315         }
 316
 317         if ((need_priv != 0) && (is_privileged == 0)) {
 318                 winbind_close_sock();
 319         }
 320
 321         if (winbindd_fd != -1) {
 322                 return winbindd_fd;
 323         }
 324
 325         if (recursing) {
 326                 return -1;
 327         }
 328
 329         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 330                 return -1;
 331         }
 332
 333         is_privileged = 0;
 334
 335         /* version-check the socket */
 336
 337         request.wb_flags = WBFLAG_RECURSE;
 338         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 339                 winbind_close_sock();
 340                 return -1;
 341         }
 342
 343         /* try and get priv pipe */
 344
 345         request.wb_flags = WBFLAG_RECURSE;
 346         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 347                 int fd;
 348                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 349                         close(winbindd_fd);
 350                         winbindd_fd = fd;
 351                         is_privileged = 1;
 352                 }
 353         }
 354
 355         if ((need_priv != 0) && (is_privileged == 0)) {
 356                 return -1;
 357         }
 358
 359         SAFE_FREE(response.extra_data.data);
 360
 361         return winbindd_fd;
 362 #else
 363         return -1;
 364 #endif /* HAVE_UNIXSOCKET */
 365 }
 366
 367 /* Write data to winbindd socket */
 368
 369 static int winbind_write_sock(void *buffer, int count, int recursing,
 370                               int need_priv)
 371 {
 372         int result, nwritten;
 373
 374         /* Open connection to winbind daemon */
 375
 376  restart:
 377
 378         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 379                 errno = ENOENT;
 380                 return -1;
 381         }
 382
 383         /* Write data to socket */
 384
 385         nwritten = 0;
 386
 387         while(nwritten < count) {
 388                 struct pollfd pfd;
 389                 int ret;
 390
 391                 /* Catch pipe close on other end by checking if a read()
 392                    call would not block by calling poll(). */
 393
 394                 pfd.fd = winbindd_fd;
 395                 pfd.events = POLLIN|POLLHUP;
 396
 397                 ret = poll(&pfd, 1, 0);
 398                 if (ret == -1) {
 399                         winbind_close_sock();
 400                         return -1;                   /* poll error */
 401                 }
 402
 403                 /* Write should be OK if fd not available for reading */
 404
 405                 if ((ret == 1) && (pfd.revents & (POLLIN|POLLHUP|POLLERR))) {
 406
 407                         /* Pipe has closed on remote end */
 408
 409                         winbind_close_sock();
 410                         goto restart;
 411                 }
 412
 413                 /* Do the write */
 414
 415                 result = write(winbindd_fd,
 416                                (char *)buffer + nwritten,
 417                                count - nwritten);
 418
 419                 if ((result == -1) || (result == 0)) {
 420
 421                         /* Write failed */
 422
 423                         winbind_close_sock();
 424                         return -1;
 425                 }
 426
 427                 nwritten += result;
 428         }
 429
 430         return nwritten;
 431 }
 432
 433 /* Read data from winbindd socket */
 434
 435 static int winbind_read_sock(void *buffer, int count)
 436 {
 437         int nread = 0;
 438         int total_time = 0;
 439
 440         if (winbindd_fd == -1) {
 441                 return -1;
 442         }
 443
 444         /* Read data from socket */
 445         while(nread < count) {
 446                 struct pollfd pfd;
 447                 int ret;
 448
 449                 /* Catch pipe close on other end by checking if a read()
 450                    call would not block by calling poll(). */
 451
 452                 pfd.fd = winbindd_fd;
 453                 pfd.events = POLLIN|POLLHUP;
 454
 455                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 456
 457                 ret = poll(&pfd, 1, 5000);
 458                 if (ret == -1) {
 459                         winbind_close_sock();
 460                         return -1;                   /* poll error */
 461                 }
 462
 463                 if (ret == 0) {
 464                         /* Not ready for read yet... */
 465                         if (total_time >= 30) {
 466                                 /* Timeout */
 467                                 winbind_close_sock();
 468                                 return -1;
 469                         }
 470                         total_time += 5;
 471                         continue;
 472                 }
 473
 474                 if ((ret == 1) && (pfd.revents & (POLLIN|POLLHUP|POLLERR))) {
 475
 476                         /* Do the Read */
 477
 478                         int result = read(winbindd_fd, (char *)buffer + nread,
 479                               count - nread);
 480
 481                         if ((result == -1) || (result == 0)) {
 482
 483                                 /* Read failed.  I think the only useful thing we
 484                                    can do here is just return -1 and fail since the
 485                                    transaction has failed half way through. */
 486
 487                                 winbind_close_sock();
 488                                 return -1;
 489                         }
 490
 491                         nread += result;
 492
 493                 }
 494         }
 495
 496         return nread;
 497 }
 498
 499 /* Read reply */
 500
 501 static int winbindd_read_reply(struct winbindd_response *response)
 502 {
 503         int result1, result2 = 0;
 504
 505         if (!response) {
 506                 return -1;
 507         }
 508
 509         /* Read fixed length response */
 510
 511         result1 = winbind_read_sock(response,
 512                                     sizeof(struct winbindd_response));
 513         if (result1 == -1) {
 514                 return -1;
 515         }
 516
 517         if (response->length < sizeof(struct winbindd_response)) {
 518                 return -1;
 519         }
 520
 521         /* We actually send the pointer value of the extra_data field from
 522            the server.  This has no meaning in the client's address space
 523            so we clear it out. */
 524
 525         response->extra_data.data = NULL;
 526
 527         /* Read variable length response */
 528
 529         if (response->length > sizeof(struct winbindd_response)) {
 530                 int extra_data_len = response->length -
 531                         sizeof(struct winbindd_response);
 532
 533                 /* Mallocate memory for extra data */
 534
 535                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 536                         return -1;
 537                 }
 538
 539                 result2 = winbind_read_sock(response->extra_data.data,
 540                                             extra_data_len);
 541                 if (result2 == -1) {
 542                         winbindd_free_response(response);
 543                         return -1;
 544                 }
 545         }
 546
 547         /* Return total amount of data read */
 548
 549         return result1 + result2;
 550 }
 551
 552 /*
 553  * send simple types of requests
 554  */
 555
 556 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 557                                  struct winbindd_request *request)
 558 {
 559         struct winbindd_request lrequest;
 560
 561         /* Check for our tricky environment variable */
 562
 563         if (winbind_env_set()) {
 564                 return NSS_STATUS_NOTFOUND;
 565         }
 566
 567         if (!request) {
 568                 ZERO_STRUCT(lrequest);
 569                 request = &lrequest;
 570         }
 571
 572         /* Fill in request and send down pipe */
 573
 574         winbindd_init_request(request, req_type);
 575
 576         if (winbind_write_sock(request, sizeof(*request),
 577                                request->wb_flags & WBFLAG_RECURSE,
 578                                need_priv) == -1)
 579         {
 580                 /* Set ENOENT for consistency.  Required by some apps */
 581                 errno = ENOENT;
 582
 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         {
 592                 /* Set ENOENT for consistency.  Required by some apps */
 593                 errno = ENOENT;
 594
 595                 return NSS_STATUS_UNAVAIL;
 596         }
 597
 598         return NSS_STATUS_SUCCESS;
 599 }
 600
 601 /*
 602  * Get results from winbindd request
 603  */
 604
 605 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 606 {
 607         struct winbindd_response lresponse;
 608
 609         if (!response) {
 610                 ZERO_STRUCT(lresponse);
 611                 response = &lresponse;
 612         }
 613
 614         init_response(response);
 615
 616         /* Wait for reply */
 617         if (winbindd_read_reply(response) == -1) {
 618                 /* Set ENOENT for consistency.  Required by some apps */
 619                 errno = ENOENT;
 620
 621                 return NSS_STATUS_UNAVAIL;
 622         }
 623
 624         /* Throw away extra data if client didn't request it */
 625         if (response == &lresponse) {
 626                 winbindd_free_response(response);
 627         }
 628
 629         /* Copy reply data from socket */
 630         if (response->result != WINBINDD_OK) {
 631                 return NSS_STATUS_NOTFOUND;
 632         }
 633
 634         return NSS_STATUS_SUCCESS;
 635 }
 636
 637 /* Handle simple types of requests */
 638
 639 NSS_STATUS winbindd_request_response(int req_type,
 640                             struct winbindd_request *request,
 641                             struct winbindd_response *response)
 642 {
 643         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 644         int count = 0;
 645
 646         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 647                 status = winbindd_send_request(req_type, 0, request);
 648                 if (status != NSS_STATUS_SUCCESS)
 649                         return(status);
 650                 status = winbindd_get_response(response);
 651                 count += 1;
 652         }
 653
 654         return status;
 655 }
 656
 657 NSS_STATUS winbindd_priv_request_response(int req_type,
 658                                           struct winbindd_request *request,
 659                                           struct winbindd_response *response)
 660 {
 661         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 662         int count = 0;
 663
 664         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 665                 status = winbindd_send_request(req_type, 1, request);
 666                 if (status != NSS_STATUS_SUCCESS)
 667                         return(status);
 668                 status = winbindd_get_response(response);
 669                 count += 1;
 670         }
 671
 672         return status;
 673 }