source4/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 "includes.h"
  28 #include "nsswitch/winbind_client.h"
  29
  30 /* Global variables.  These are effectively the client state information */
  31
  32 int winbindd_fd = -1;           /* fd for winbindd socket */
  33
  34 /* Free a response structure */
  35
  36 void free_response(struct winbindd_response *response)
  37 {
  38         /* Free any allocated extra_data */
  39
  40         if (response)
  41                 SAFE_FREE(response->extra_data);
  42 }
  43
  44 /* Initialise a request structure */
  45
  46 void init_request(struct winbindd_request *request, int request_type)
  47 {
  48         request->length = sizeof(struct winbindd_request);
  49
  50         request->cmd = (enum winbindd_cmd)request_type;
  51         request->pid = getpid();
  52
  53 }
  54
  55 /* Initialise a response structure */
  56
  57 void init_response(struct winbindd_response *response)
  58 {
  59         /* Initialise return value */
  60
  61         response->result = WINBINDD_ERROR;
  62 }
  63
  64 /* Close established socket */
  65
  66 void close_sock(void)
  67 {
  68         if (winbindd_fd != -1) {
  69                 close(winbindd_fd);
  70                 winbindd_fd = -1;
  71         }
  72 }
  73
  74 #define CONNECT_TIMEOUT 30
  75 #if 0 /* unused */
  76 #define WRITE_TIMEOUT CONNECT_TIMEOUT
  77 #define READ_TIMEOUT CONNECT_TIMEOUT
  78 #endif
  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;
 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                 return -1;
 186         }
 187
 188         if (!S_ISDIR(st.st_mode) ||
 189             (st.st_uid != 0 && st.st_uid != geteuid())) {
 190                 return -1;
 191         }
 192
 193         /* Connect to socket */
 194
 195         asprintf(&path, "%s%s", dir, "/" WINBINDD_SOCKET_NAME);
 196         ZERO_STRUCT(sunaddr);
 197         sunaddr.sun_family = AF_UNIX;
 198         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 199
 200         /* If socket file doesn't exist, don't bother trying to connect
 201            with retry.  This is an attempt to make the system usable when
 202            the winbindd daemon is not running. */
 203
 204         if (lstat(path, &st) == -1) {
 205                 SAFE_FREE(path);
 206                 return -1;
 207         }
 208
 209         SAFE_FREE(path);
 210
 211         /* Check permissions on unix socket file */
 212
 213         if (!S_ISSOCK(st.st_mode) ||
 214             (st.st_uid != 0 && st.st_uid != geteuid())) {
 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         if (connect(fd, (struct sockaddr *)&sunaddr,
 284                     sizeof(sunaddr)) == -1) {
 285                 close(fd);
 286                 return -1;
 287         }
 288
 289         return fd;
 290 }
 291
 292 /* Connect to winbindd socket */
 293
 294 int winbind_open_pipe_sock(void)
 295 {
 296 #ifdef HAVE_UNIXSOCKET
 297         static pid_t our_pid;
 298         struct winbindd_request request;
 299         struct winbindd_response response;
 300         ZERO_STRUCT(request);
 301         ZERO_STRUCT(response);
 302
 303         if (our_pid != getpid()) {
 304                 close_sock();
 305                 our_pid = getpid();
 306         }
 307
 308         if (winbindd_fd != -1) {
 309                 return winbindd_fd;
 310         }
 311
 312         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 313                 return -1;
 314         }
 315
 316         /* version-check the socket */
 317
 318         if ((winbindd_request(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 319                 close_sock();
 320                 return -1;
 321         }
 322
 323         /* try and get priv pipe */
 324
 325         if (winbindd_request(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)
 344 {
 345         int result, nwritten;
 346
 347         /* Open connection to winbind daemon */
 348
 349  restart:
 350
 351         if (winbind_open_pipe_sock() == -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)) == -1) {
 545                 return NSS_STATUS_UNAVAIL;
 546         }
 547
 548         return NSS_STATUS_SUCCESS;
 549 }
 550
 551 /*
 552  * Get results from winbindd request
 553  */
 554
 555 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 556 {
 557         struct winbindd_response lresponse;
 558
 559         if (!response) {
 560                 ZERO_STRUCT(lresponse);
 561                 response = &lresponse;
 562         }
 563
 564         init_response(response);
 565
 566         /* Wait for reply */
 567         if (read_reply(response) == -1) {
 568                 return NSS_STATUS_UNAVAIL;
 569         }
 570
 571         /* Throw away extra data if client didn't request it */
 572         if (response == &lresponse) {
 573                 free_response(response);
 574         }
 575
 576         /* Copy reply data from socket */
 577         if (response->result != WINBINDD_OK) {
 578                 return NSS_STATUS_NOTFOUND;
 579         }
 580
 581         return NSS_STATUS_SUCCESS;
 582 }
 583
 584 /* Handle simple types of requests */
 585
 586 NSS_STATUS winbindd_request(int req_type,
 587                             struct winbindd_request *request,
 588                             struct winbindd_response *response)
 589 {
 590         NSS_STATUS status;
 591
 592         status = winbindd_send_request(req_type, request);
 593         if (status != NSS_STATUS_SUCCESS)
 594                 return(status);
 595         return winbindd_get_response(response);
 596 }
 597
 598 /*************************************************************************
 599  A couple of simple functions to disable winbindd lookups and re-
 600  enable them
 601  ************************************************************************/
 602
 603 BOOL winbind_off( void )
 604 {
 605         setenv(WINBINDD_DONT_ENV, "1", 1);
 606         return True;
 607 }
 608
 609 BOOL winbind_on( void )
 610 {
 611         setenv(WINBINDD_DONT_ENV, "0", 1);
 612         return True;
 613 }