source/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 BOOL winbind_env_set( void );
  30 BOOL winbind_off( void );
  31 BOOL winbind_on( void );
  32
  33 /* Global variables.  These are effectively the client state information */
  34
  35 int winbindd_fd = -1;           /* fd for winbindd socket */
  36 static int is_privileged = 0;
  37
  38 /* Free a response structure */
  39
  40 void free_response(struct winbindd_response *response)
  41 {
  42         /* Free any allocated extra_data */
  43
  44         if (response)
  45                 SAFE_FREE(response->extra_data.data);
  46 }
  47
  48 /* Initialise a request structure */
  49
  50 void init_request(struct winbindd_request *request, int request_type)
  51 {
  52         request->length = sizeof(struct winbindd_request);
  53
  54         request->cmd = (enum winbindd_cmd)request_type;
  55         request->pid = getpid();
  56
  57 }
  58
  59 /* Initialise a response structure */
  60
  61 static void init_response(struct winbindd_response *response)
  62 {
  63         /* Initialise return value */
  64
  65         response->result = WINBINDD_ERROR;
  66 }
  67
  68 /* Close established socket */
  69
  70 void 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         pstring 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                 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         strncpy(path, dir, sizeof(path) - 1);
 198         path[sizeof(path) - 1] = '\0';
 199
 200         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 201         path[sizeof(path) - 1] = '\0';
 202
 203         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 204         path[sizeof(path) - 1] = '\0';
 205
 206         ZERO_STRUCT(sunaddr);
 207         sunaddr.sun_family = AF_UNIX;
 208         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 209
 210         /* If socket file doesn't exist, don't bother trying to connect
 211            with retry.  This is an attempt to make the system usable when
 212            the winbindd daemon is not running. */
 213
 214         if (lstat(path, &st) == -1) {
 215                 errno = ENOENT;
 216                 return -1;
 217         }
 218
 219         /* Check permissions on unix socket file */
 220
 221         if (!S_ISSOCK(st.st_mode) ||
 222             (st.st_uid != 0 && st.st_uid != geteuid())) {
 223                 errno = ENOENT;
 224                 return -1;
 225         }
 226
 227         /* Connect to socket */
 228
 229         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 230                 return -1;
 231         }
 232
 233         /* Set socket non-blocking and close on exec. */
 234
 235         if ((fd = make_safe_fd( fd)) == -1) {
 236                 return fd;
 237         }
 238
 239         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 240                         wait_time += slept) {
 241                 struct timeval tv;
 242                 fd_set w_fds;
 243                 int ret;
 244                 int connect_errno = 0;
 245                 socklen_t errnosize;
 246
 247                 if (wait_time >= CONNECT_TIMEOUT)
 248                         goto error_out;
 249
 250                 switch (errno) {
 251                         case EINPROGRESS:
 252                                 FD_ZERO(&w_fds);
 253                                 FD_SET(fd, &w_fds);
 254                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 255                                 tv.tv_usec = 0;
 256
 257                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 258
 259                                 if (ret > 0) {
 260                                         errnosize = sizeof(connect_errno);
 261
 262                                         ret = getsockopt(fd, SOL_SOCKET,
 263                                                         SO_ERROR, &connect_errno, &errnosize);
 264
 265                                         if (ret >= 0 && connect_errno == 0) {
 266                                                 /* Connect succeed */
 267                                                 goto out;
 268                                         }
 269                                 }
 270
 271                                 slept = CONNECT_TIMEOUT;
 272                                 break;
 273                         case EAGAIN:
 274                                 slept = rand() % 3 + 1;
 275                                 sleep(slept);
 276                                 break;
 277                         default:
 278                                 goto error_out;
 279                 }
 280
 281         }
 282
 283   out:
 284
 285         return fd;
 286
 287   error_out:
 288
 289         close(fd);
 290         return -1;
 291 }
 292
 293 /* Connect to winbindd socket */
 294
 295 static int winbind_open_pipe_sock(int recursing, int need_priv)
 296 {
 297 #ifdef HAVE_UNIXSOCKET
 298         static pid_t our_pid;
 299         struct winbindd_request request;
 300         struct winbindd_response response;
 301         ZERO_STRUCT(request);
 302         ZERO_STRUCT(response);
 303
 304         if (our_pid != getpid()) {
 305                 close_sock();
 306                 our_pid = getpid();
 307         }
 308
 309         if ((need_priv != 0) && (is_privileged == 0)) {
 310                 close_sock();
 311         }
 312
 313         if (winbindd_fd != -1) {
 314                 return winbindd_fd;
 315         }
 316
 317         if (recursing) {
 318                 return -1;
 319         }
 320
 321         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 322                 return -1;
 323         }
 324
 325         is_privileged = 0;
 326
 327         /* version-check the socket */
 328
 329         request.flags = WBFLAG_RECURSE;
 330         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 331                 close_sock();
 332                 return -1;
 333         }
 334
 335         /* try and get priv pipe */
 336
 337         request.flags = WBFLAG_RECURSE;
 338         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 339                 int fd;
 340                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 341                         close(winbindd_fd);
 342                         winbindd_fd = fd;
 343                         is_privileged = 1;
 344                 }
 345         }
 346
 347         if ((need_priv != 0) && (is_privileged == 0)) {
 348                 return -1;
 349         }
 350
 351         SAFE_FREE(response.extra_data.data);
 352
 353         return winbindd_fd;
 354 #else
 355         return -1;
 356 #endif /* HAVE_UNIXSOCKET */
 357 }
 358
 359 /* Write data to winbindd socket */
 360
 361 int write_sock(void *buffer, int count, int recursing, int need_priv)
 362 {
 363         int result, nwritten;
 364
 365         /* Open connection to winbind daemon */
 366
 367  restart:
 368
 369         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 370                 errno = ENOENT;
 371                 return -1;
 372         }
 373
 374         /* Write data to socket */
 375
 376         nwritten = 0;
 377
 378         while(nwritten < count) {
 379                 struct timeval tv;
 380                 fd_set r_fds;
 381
 382                 /* Catch pipe close on other end by checking if a read()
 383                    call would not block by calling select(). */
 384
 385                 FD_ZERO(&r_fds);
 386                 FD_SET(winbindd_fd, &r_fds);
 387                 ZERO_STRUCT(tv);
 388
 389                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 390                         close_sock();
 391                         return -1;                   /* Select error */
 392                 }
 393
 394                 /* Write should be OK if fd not available for reading */
 395
 396                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 397
 398                         /* Do the write */
 399
 400                         result = write(winbindd_fd,
 401                                        (char *)buffer + nwritten,
 402                                        count - nwritten);
 403
 404                         if ((result == -1) || (result == 0)) {
 405
 406                                 /* Write failed */
 407
 408                                 close_sock();
 409                                 return -1;
 410                         }
 411
 412                         nwritten += result;
 413
 414                 } else {
 415
 416                         /* Pipe has closed on remote end */
 417
 418                         close_sock();
 419                         goto restart;
 420                 }
 421         }
 422
 423         return nwritten;
 424 }
 425
 426 /* Read data from winbindd socket */
 427
 428 static int read_sock(void *buffer, int count)
 429 {
 430         int nread = 0;
 431         int total_time = 0, selret;
 432
 433         if (winbindd_fd == -1) {
 434                 return -1;
 435         }
 436
 437         /* Read data from socket */
 438         while(nread < count) {
 439                 struct timeval tv;
 440                 fd_set r_fds;
 441
 442                 /* Catch pipe close on other end by checking if a read()
 443                    call would not block by calling select(). */
 444
 445                 FD_ZERO(&r_fds);
 446                 FD_SET(winbindd_fd, &r_fds);
 447                 ZERO_STRUCT(tv);
 448                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 449                 tv.tv_sec = 5;
 450
 451                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 452                         close_sock();
 453                         return -1;                   /* Select error */
 454                 }
 455
 456                 if (selret == 0) {
 457                         /* Not ready for read yet... */
 458                         if (total_time >= 30) {
 459                                 /* Timeout */
 460                                 close_sock();
 461                                 return -1;
 462                         }
 463                         total_time += 5;
 464                         continue;
 465                 }
 466
 467                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 468
 469                         /* Do the Read */
 470
 471                         int result = read(winbindd_fd, (char *)buffer + nread,
 472                               count - nread);
 473
 474                         if ((result == -1) || (result == 0)) {
 475
 476                                 /* Read failed.  I think the only useful thing we
 477                                    can do here is just return -1 and fail since the
 478                                    transaction has failed half way through. */
 479
 480                                 close_sock();
 481                                 return -1;
 482                         }
 483
 484                         nread += result;
 485
 486                 }
 487         }
 488
 489         return nread;
 490 }
 491
 492 /* Read reply */
 493
 494 int read_reply(struct winbindd_response *response)
 495 {
 496         int result1, result2 = 0;
 497
 498         if (!response) {
 499                 return -1;
 500         }
 501
 502         /* Read fixed length response */
 503
 504         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 505             == -1) {
 506
 507                 return -1;
 508         }
 509
 510         /* We actually send the pointer value of the extra_data field from
 511            the server.  This has no meaning in the client's address space
 512            so we clear it out. */
 513
 514         response->extra_data.data = NULL;
 515
 516         /* Read variable length response */
 517
 518         if (response->length > sizeof(struct winbindd_response)) {
 519                 int extra_data_len = response->length -
 520                         sizeof(struct winbindd_response);
 521
 522                 /* Mallocate memory for extra data */
 523
 524                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 525                         return -1;
 526                 }
 527
 528                 if ((result2 = read_sock(response->extra_data.data, extra_data_len))
 529                     == -1) {
 530                         free_response(response);
 531                         return -1;
 532                 }
 533         }
 534
 535         /* Return total amount of data read */
 536
 537         return result1 + result2;
 538 }
 539
 540 BOOL winbind_env_set( void )
 541 {
 542         char *env;
 543
 544         if ((env=getenv(WINBINDD_DONT_ENV)) != NULL) {
 545                 if(strcmp(env, "1") == 0) {
 546                         return True;
 547                 }
 548         }
 549         return False;
 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         init_request(request, req_type);
 575
 576         if (write_sock(request, sizeof(*request),
 577                        request->flags & WBFLAG_RECURSE, need_priv) == -1) {
 578                 /* Set ENOENT for consistency.  Required by some apps */
 579                 errno = ENOENT;
 580
 581                 return NSS_STATUS_UNAVAIL;
 582         }
 583
 584         if ((request->extra_len != 0) &&
 585             (write_sock(request->extra_data.data, request->extra_len,
 586                         request->flags & WBFLAG_RECURSE, need_priv) == -1)) {
 587                 /* Set ENOENT for consistency.  Required by some apps */
 588                 errno = ENOENT;
 589
 590                 return NSS_STATUS_UNAVAIL;
 591         }
 592
 593         return NSS_STATUS_SUCCESS;
 594 }
 595
 596 /*
 597  * Get results from winbindd request
 598  */
 599
 600 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 601 {
 602         struct winbindd_response lresponse;
 603
 604         if (!response) {
 605                 ZERO_STRUCT(lresponse);
 606                 response = &lresponse;
 607         }
 608
 609         init_response(response);
 610
 611         /* Wait for reply */
 612         if (read_reply(response) == -1) {
 613                 /* Set ENOENT for consistency.  Required by some apps */
 614                 errno = ENOENT;
 615
 616                 return NSS_STATUS_UNAVAIL;
 617         }
 618
 619         /* Throw away extra data if client didn't request it */
 620         if (response == &lresponse) {
 621                 free_response(response);
 622         }
 623
 624         /* Copy reply data from socket */
 625         if (response->result != WINBINDD_OK) {
 626                 return NSS_STATUS_NOTFOUND;
 627         }
 628
 629         return NSS_STATUS_SUCCESS;
 630 }
 631
 632 /* Handle simple types of requests */
 633
 634 NSS_STATUS winbindd_request_response(int req_type,
 635                             struct winbindd_request *request,
 636                             struct winbindd_response *response)
 637 {
 638         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 639         int count = 0;
 640
 641         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 642                 status = winbindd_send_request(req_type, 0, request);
 643                 if (status != NSS_STATUS_SUCCESS)
 644                         return(status);
 645                 status = winbindd_get_response(response);
 646                 count += 1;
 647         }
 648
 649         return status;
 650 }
 651
 652 NSS_STATUS winbindd_priv_request_response(int req_type,
 653                                           struct winbindd_request *request,
 654                                           struct winbindd_response *response)
 655 {
 656         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 657         int count = 0;
 658
 659         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 660                 status = winbindd_send_request(req_type, 1, request);
 661                 if (status != NSS_STATUS_SUCCESS)
 662                         return(status);
 663                 status = winbindd_get_response(response);
 664                 count += 1;
 665         }
 666
 667         return status;
 668 }
 669
 670 /*************************************************************************
 671  A couple of simple functions to disable winbindd lookups and re-
 672  enable them
 673  ************************************************************************/
 674
 675 /* Use putenv() instead of setenv() in these functions as not all
 676    environments have the latter. */
 677
 678 BOOL winbind_off( void )
 679 {
 680         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=1");
 681
 682         return putenv(s) != -1;
 683 }
 684
 685 BOOL winbind_on( void )
 686 {
 687         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=0");
 688
 689         return putenv(s) != -1;
 690 }
 691