source3/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 Library General Public
  13    License as published by the Free Software Foundation; either
  14    version 2 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 Library General Public
  22    License along with this library; if not, write to the
  23    Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24    Boston, MA  02111-1307, USA.
  25 */
  26
  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
  33 /* Free a response structure */
  34
  35 void free_response(struct winbindd_response *response)
  36 {
  37         /* Free any allocated extra_data */
  38
  39         if (response)
  40                 SAFE_FREE(response->extra_data);
  41 }
  42
  43 /* Initialise a request structure */
  44
  45 void init_request(struct winbindd_request *request, 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 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 void close_sock(void)
  66 {
  67         if (winbindd_fd != -1) {
  68                 close(winbindd_fd);
  69                 winbindd_fd = -1;
  70         }
  71 }
  72
  73 #define CONNECT_TIMEOUT 30
  74 #define WRITE_TIMEOUT CONNECT_TIMEOUT
  75 #define READ_TIMEOUT CONNECT_TIMEOUT
  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         pstring path;
 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                 return -1;
 183         }
 184
 185         if (!S_ISDIR(st.st_mode) ||
 186             (st.st_uid != 0 && st.st_uid != geteuid())) {
 187                 return -1;
 188         }
 189
 190         /* Connect to socket */
 191
 192         strncpy(path, dir, sizeof(path) - 1);
 193         path[sizeof(path) - 1] = '\0';
 194
 195         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 196         path[sizeof(path) - 1] = '\0';
 197
 198         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 199         path[sizeof(path) - 1] = '\0';
 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                 return -1;
 211         }
 212
 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                 return -1;
 218         }
 219
 220         /* Connect to socket */
 221
 222         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 223                 return -1;
 224         }
 225
 226         /* Set socket non-blocking and close on exec. */
 227
 228         if ((fd = make_safe_fd( fd)) == -1) {
 229                 return fd;
 230         }
 231
 232         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 233                         wait_time += slept) {
 234                 struct timeval tv;
 235                 fd_set w_fds;
 236                 int ret;
 237                 int connect_errno = 0;
 238                 socklen_t errnosize;
 239
 240                 if (wait_time >= CONNECT_TIMEOUT)
 241                         goto error_out;
 242
 243                 switch (errno) {
 244                         case EINPROGRESS:
 245                                 FD_ZERO(&w_fds);
 246                                 FD_SET(fd, &w_fds);
 247                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 248                                 tv.tv_usec = 0;
 249
 250                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 251
 252                                 if (ret > 0) {
 253                                         errnosize = sizeof(connect_errno);
 254
 255                                         ret = getsockopt(fd, SOL_SOCKET,
 256                                                         SO_ERROR, &connect_errno, &errnosize);
 257
 258                                         if (ret >= 0 && connect_errno == 0) {
 259                                                 /* Connect succeed */
 260                                                 goto out;
 261                                         }
 262                                 }
 263
 264                                 slept = CONNECT_TIMEOUT;
 265                                 break;
 266                         case EAGAIN:
 267                                 slept = rand() % 3 + 1;
 268                                 sleep(slept);
 269                                 break;
 270                         default:
 271                                 goto error_out;
 272                 }
 273
 274         }
 275
 276   out:
 277
 278         return fd;
 279
 280   error_out:
 281
 282         close(fd);
 283         return -1;
 284 }
 285
 286 /* Connect to winbindd socket */
 287
 288 static int winbind_open_pipe_sock(int recursing)
 289 {
 290 #ifdef HAVE_UNIXSOCKET
 291         static pid_t our_pid;
 292         struct winbindd_request request;
 293         struct winbindd_response response;
 294         ZERO_STRUCT(request);
 295         ZERO_STRUCT(response);
 296
 297         if (our_pid != getpid()) {
 298                 close_sock();
 299                 our_pid = getpid();
 300         }
 301
 302         if (winbindd_fd != -1) {
 303                 return winbindd_fd;
 304         }
 305
 306         if (recursing) {
 307                 return -1;
 308         }
 309
 310         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 311                 return -1;
 312         }
 313
 314         /* version-check the socket */
 315
 316         request.flags = WBFLAG_RECURSE;
 317         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 318                 close_sock();
 319                 return -1;
 320         }
 321
 322         /* try and get priv pipe */
 323
 324         request.flags = WBFLAG_RECURSE;
 325         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 326                 int fd;
 327                 if ((fd = winbind_named_pipe_sock(response.extra_data)) != -1) {
 328                         close(winbindd_fd);
 329                         winbindd_fd = fd;
 330                 }
 331         }
 332
 333         SAFE_FREE(response.extra_data);
 334
 335         return winbindd_fd;
 336 #else
 337         return -1;
 338 #endif /* HAVE_UNIXSOCKET */
 339 }
 340
 341 /* Write data to winbindd socket */
 342
 343 int write_sock(void *buffer, int count, int recursing)
 344 {
 345         int result, nwritten;
 346
 347         /* Open connection to winbind daemon */
 348
 349  restart:
 350
 351         if (winbind_open_pipe_sock(recursing) == -1) {
 352                 return -1;
 353         }
 354
 355         /* Write data to socket */
 356
 357         nwritten = 0;
 358
 359         while(nwritten < count) {
 360                 struct timeval tv;
 361                 fd_set r_fds;
 362
 363                 /* Catch pipe close on other end by checking if a read()
 364                    call would not block by calling select(). */
 365
 366                 FD_ZERO(&r_fds);
 367                 FD_SET(winbindd_fd, &r_fds);
 368                 ZERO_STRUCT(tv);
 369
 370                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 371                         close_sock();
 372                         return -1;                   /* Select error */
 373                 }
 374
 375                 /* Write should be OK if fd not available for reading */
 376
 377                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 378
 379                         /* Do the write */
 380
 381                         result = write(winbindd_fd,
 382                                        (char *)buffer + nwritten,
 383                                        count - nwritten);
 384
 385                         if ((result == -1) || (result == 0)) {
 386
 387                                 /* Write failed */
 388
 389                                 close_sock();
 390                                 return -1;
 391                         }
 392
 393                         nwritten += result;
 394
 395                 } else {
 396
 397                         /* Pipe has closed on remote end */
 398
 399                         close_sock();
 400                         goto restart;
 401                 }
 402         }
 403
 404         return nwritten;
 405 }
 406
 407 /* Read data from winbindd socket */
 408
 409 static int read_sock(void *buffer, int count)
 410 {
 411         int result = 0, nread = 0;
 412         int total_time = 0, selret;
 413
 414         /* Read data from socket */
 415         while(nread < count) {
 416                 struct timeval tv;
 417                 fd_set r_fds;
 418
 419                 /* Catch pipe close on other end by checking if a read()
 420                    call would not block by calling select(). */
 421
 422                 FD_ZERO(&r_fds);
 423                 FD_SET(winbindd_fd, &r_fds);
 424                 ZERO_STRUCT(tv);
 425                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 426                 tv.tv_sec = 5;
 427
 428                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 429                         close_sock();
 430                         return -1;                   /* Select error */
 431                 }
 432
 433                 if (selret == 0) {
 434                         /* Not ready for read yet... */
 435                         if (total_time >= 30) {
 436                                 /* Timeout */
 437                                 close_sock();
 438                                 return -1;
 439                         }
 440                         total_time += 5;
 441                         continue;
 442                 }
 443
 444                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 445
 446                         /* Do the Read */
 447
 448                         result = read(winbindd_fd, (char *)buffer + nread,
 449                               count - nread);
 450
 451                         if ((result == -1) || (result == 0)) {
 452
 453                                 /* Read failed.  I think the only useful thing we
 454                                    can do here is just return -1 and fail since the
 455                                    transaction has failed half way through. */
 456
 457                                 close_sock();
 458                                 return -1;
 459                         }
 460
 461                         nread += result;
 462
 463                 }
 464         }
 465
 466         return result;
 467 }
 468
 469 /* Read reply */
 470
 471 int read_reply(struct winbindd_response *response)
 472 {
 473         int result1, result2 = 0;
 474
 475         if (!response) {
 476                 return -1;
 477         }
 478
 479         /* Read fixed length response */
 480
 481         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 482             == -1) {
 483
 484                 return -1;
 485         }
 486
 487         /* We actually send the pointer value of the extra_data field from
 488            the server.  This has no meaning in the client's address space
 489            so we clear it out. */
 490
 491         response->extra_data = NULL;
 492
 493         /* Read variable length response */
 494
 495         if (response->length > sizeof(struct winbindd_response)) {
 496                 int extra_data_len = response->length -
 497                         sizeof(struct winbindd_response);
 498
 499                 /* Mallocate memory for extra data */
 500
 501                 if (!(response->extra_data = malloc(extra_data_len))) {
 502                         return -1;
 503                 }
 504
 505                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 506                     == -1) {
 507                         free_response(response);
 508                         return -1;
 509                 }
 510         }
 511
 512         /* Return total amount of data read */
 513
 514         return result1 + result2;
 515 }
 516
 517 /*
 518  * send simple types of requests
 519  */
 520
 521 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 522 {
 523         struct winbindd_request lrequest;
 524         char *env;
 525         int  value;
 526
 527         /* Check for our tricky environment variable */
 528
 529         if ( (env = getenv(WINBINDD_DONT_ENV)) != NULL ) {
 530                 value = atoi(env);
 531                 if ( value == 1 )
 532                         return NSS_STATUS_NOTFOUND;
 533         }
 534
 535         if (!request) {
 536                 ZERO_STRUCT(lrequest);
 537                 request = &lrequest;
 538         }
 539
 540         /* Fill in request and send down pipe */
 541
 542         init_request(request, req_type);
 543
 544         if (write_sock(request, sizeof(*request), request->flags & WBFLAG_RECURSE) == -1) {
 545                 return NSS_STATUS_UNAVAIL;
 546         }
 547
 548         if ((request->extra_len != 0) &&
 549             (write_sock(request->extra_data, request->extra_len, request->flags & WBFLAG_RECURSE) == -1)) {
 550                 return NSS_STATUS_UNAVAIL;
 551         }
 552
 553         return NSS_STATUS_SUCCESS;
 554 }
 555
 556 /*
 557  * Get results from winbindd request
 558  */
 559
 560 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 561 {
 562         struct winbindd_response lresponse;
 563
 564         if (!response) {
 565                 ZERO_STRUCT(lresponse);
 566                 response = &lresponse;
 567         }
 568
 569         init_response(response);
 570
 571         /* Wait for reply */
 572         if (read_reply(response) == -1) {
 573                 return NSS_STATUS_UNAVAIL;
 574         }
 575
 576         /* Throw away extra data if client didn't request it */
 577         if (response == &lresponse) {
 578                 free_response(response);
 579         }
 580
 581         /* Copy reply data from socket */
 582         if (response->result != WINBINDD_OK) {
 583                 return NSS_STATUS_NOTFOUND;
 584         }
 585
 586         return NSS_STATUS_SUCCESS;
 587 }
 588
 589 /* Handle simple types of requests */
 590
 591 NSS_STATUS winbindd_request_response(int req_type,
 592                             struct winbindd_request *request,
 593                             struct winbindd_response *response)
 594 {
 595         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 596         int count = 0;
 597
 598         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 599                 status = winbindd_send_request(req_type, request);
 600                 if (status != NSS_STATUS_SUCCESS)
 601                         return(status);
 602                 status = winbindd_get_response(response);
 603                 count += 1;
 604         }
 605
 606         return status;
 607 }
 608
 609 /*************************************************************************
 610  A couple of simple functions to disable winbindd lookups and re-
 611  enable them
 612  ************************************************************************/
 613
 614 /* Use putenv() instead of setenv() in these functions as not all
 615    environments have the latter. */
 616
 617 BOOL winbind_off( void )
 618 {
 619         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=1");
 620
 621         return putenv(s) != -1;
 622 }
 623
 624 BOOL winbind_on( void )
 625 {
 626         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=0");
 627
 628         return putenv(s) != -1;
 629 }