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                 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         strncpy(path, dir, sizeof(path) - 1);
 196         path[sizeof(path) - 1] = '\0';
 197
 198         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 199         path[sizeof(path) - 1] = '\0';
 200
 201         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 202         path[sizeof(path) - 1] = '\0';
 203
 204         ZERO_STRUCT(sunaddr);
 205         sunaddr.sun_family = AF_UNIX;
 206         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 207
 208         /* If socket file doesn't exist, don't bother trying to connect
 209            with retry.  This is an attempt to make the system usable when
 210            the winbindd daemon is not running. */
 211
 212         if (lstat(path, &st) == -1) {
 213                 return -1;
 214         }
 215
 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                 return -1;
 221         }
 222
 223         /* Connect to socket */
 224
 225         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 226                 return -1;
 227         }
 228
 229         /* Set socket non-blocking and close on exec. */
 230
 231         if ((fd = make_safe_fd( fd)) == -1) {
 232                 return fd;
 233         }
 234
 235         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 236                         wait_time += slept) {
 237                 struct timeval tv;
 238                 fd_set w_fds;
 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                                 FD_ZERO(&w_fds);
 249                                 FD_SET(fd, &w_fds);
 250                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 251                                 tv.tv_usec = 0;
 252
 253                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 254
 255                                 if (ret > 0) {
 256                                         errnosize = sizeof(connect_errno);
 257
 258                                         ret = getsockopt(fd, SOL_SOCKET,
 259                                                         SO_ERROR, &connect_errno, &errnosize);
 260
 261                                         if (ret >= 0 && connect_errno == 0) {
 262                                                 /* Connect succeed */
 263                                                 goto out;
 264                                         }
 265                                 }
 266
 267                                 slept = CONNECT_TIMEOUT;
 268                                 break;
 269                         case EAGAIN:
 270                                 slept = rand() % 3 + 1;
 271                                 sleep(slept);
 272                                 break;
 273                         default:
 274                                 goto error_out;
 275                 }
 276
 277         }
 278
 279   out:
 280
 281         return fd;
 282
 283   error_out:
 284
 285         close(fd);
 286         return -1;
 287 }
 288
 289 /* Connect to winbindd socket */
 290
 291 static int winbind_open_pipe_sock(int recursing, int need_priv)
 292 {
 293 #ifdef HAVE_UNIXSOCKET
 294         static pid_t our_pid;
 295         struct winbindd_request request;
 296         struct winbindd_response response;
 297         ZERO_STRUCT(request);
 298         ZERO_STRUCT(response);
 299
 300         if (our_pid != getpid()) {
 301                 close_sock();
 302                 our_pid = getpid();
 303         }
 304
 305         if ((need_priv != 0) && (is_privileged == 0)) {
 306                 close_sock();
 307         }
 308
 309         if (winbindd_fd != -1) {
 310                 return winbindd_fd;
 311         }
 312
 313         if (recursing) {
 314                 return -1;
 315         }
 316
 317         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 318                 return -1;
 319         }
 320
 321         is_privileged = 0;
 322
 323         /* version-check the socket */
 324
 325         request.flags = WBFLAG_RECURSE;
 326         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 327                 close_sock();
 328                 return -1;
 329         }
 330
 331         /* try and get priv pipe */
 332
 333         request.flags = WBFLAG_RECURSE;
 334         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 335                 int fd;
 336                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 337                         close(winbindd_fd);
 338                         winbindd_fd = fd;
 339                         is_privileged = 1;
 340                 }
 341         }
 342
 343         if ((need_priv != 0) && (is_privileged == 0)) {
 344                 return -1;
 345         }
 346
 347         SAFE_FREE(response.extra_data.data);
 348
 349         return winbindd_fd;
 350 #else
 351         return -1;
 352 #endif /* HAVE_UNIXSOCKET */
 353 }
 354
 355 /* Write data to winbindd socket */
 356
 357 int write_sock(void *buffer, int count, int recursing, int need_priv)
 358 {
 359         int result, nwritten;
 360
 361         /* Open connection to winbind daemon */
 362
 363  restart:
 364
 365         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 366                 return -1;
 367         }
 368
 369         /* Write data to socket */
 370
 371         nwritten = 0;
 372
 373         while(nwritten < count) {
 374                 struct timeval tv;
 375                 fd_set r_fds;
 376
 377                 /* Catch pipe close on other end by checking if a read()
 378                    call would not block by calling select(). */
 379
 380                 FD_ZERO(&r_fds);
 381                 FD_SET(winbindd_fd, &r_fds);
 382                 ZERO_STRUCT(tv);
 383
 384                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 385                         close_sock();
 386                         return -1;                   /* Select error */
 387                 }
 388
 389                 /* Write should be OK if fd not available for reading */
 390
 391                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 392
 393                         /* Do the write */
 394
 395                         result = write(winbindd_fd,
 396                                        (char *)buffer + nwritten,
 397                                        count - nwritten);
 398
 399                         if ((result == -1) || (result == 0)) {
 400
 401                                 /* Write failed */
 402
 403                                 close_sock();
 404                                 return -1;
 405                         }
 406
 407                         nwritten += result;
 408
 409                 } else {
 410
 411                         /* Pipe has closed on remote end */
 412
 413                         close_sock();
 414                         goto restart;
 415                 }
 416         }
 417
 418         return nwritten;
 419 }
 420
 421 /* Read data from winbindd socket */
 422
 423 static int read_sock(void *buffer, int count)
 424 {
 425         int nread = 0;
 426         int total_time = 0, selret;
 427
 428         if (winbindd_fd == -1) {
 429                 return -1;
 430         }
 431
 432         /* Read data from socket */
 433         while(nread < count) {
 434                 struct timeval tv;
 435                 fd_set r_fds;
 436
 437                 /* Catch pipe close on other end by checking if a read()
 438                    call would not block by calling select(). */
 439
 440                 FD_ZERO(&r_fds);
 441                 FD_SET(winbindd_fd, &r_fds);
 442                 ZERO_STRUCT(tv);
 443                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 444                 tv.tv_sec = 5;
 445
 446                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 447                         close_sock();
 448                         return -1;                   /* Select error */
 449                 }
 450
 451                 if (selret == 0) {
 452                         /* Not ready for read yet... */
 453                         if (total_time >= 30) {
 454                                 /* Timeout */
 455                                 close_sock();
 456                                 return -1;
 457                         }
 458                         total_time += 5;
 459                         continue;
 460                 }
 461
 462                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 463
 464                         /* Do the Read */
 465
 466                         int result = read(winbindd_fd, (char *)buffer + nread,
 467                               count - nread);
 468
 469                         if ((result == -1) || (result == 0)) {
 470
 471                                 /* Read failed.  I think the only useful thing we
 472                                    can do here is just return -1 and fail since the
 473                                    transaction has failed half way through. */
 474
 475                                 close_sock();
 476                                 return -1;
 477                         }
 478
 479                         nread += result;
 480
 481                 }
 482         }
 483
 484         return nread;
 485 }
 486
 487 /* Read reply */
 488
 489 int read_reply(struct winbindd_response *response)
 490 {
 491         int result1, result2 = 0;
 492
 493         if (!response) {
 494                 return -1;
 495         }
 496
 497         /* Read fixed length response */
 498
 499         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 500             == -1) {
 501
 502                 return -1;
 503         }
 504
 505         /* We actually send the pointer value of the extra_data field from
 506            the server.  This has no meaning in the client's address space
 507            so we clear it out. */
 508
 509         response->extra_data.data = NULL;
 510
 511         /* Read variable length response */
 512
 513         if (response->length > sizeof(struct winbindd_response)) {
 514                 int extra_data_len = response->length -
 515                         sizeof(struct winbindd_response);
 516
 517                 /* Mallocate memory for extra data */
 518
 519                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 520                         return -1;
 521                 }
 522
 523                 if ((result2 = read_sock(response->extra_data.data, extra_data_len))
 524                     == -1) {
 525                         free_response(response);
 526                         return -1;
 527                 }
 528         }
 529
 530         /* Return total amount of data read */
 531
 532         return result1 + result2;
 533 }
 534
 535 BOOL winbind_env_set( void )
 536 {
 537         char *env;
 538
 539         if ((env=getenv(WINBINDD_DONT_ENV)) != NULL) {
 540                 if(strcmp(env, "1") == 0) {
 541                         return True;
 542                 }
 543         }
 544         return False;
 545 }
 546
 547 /*
 548  * send simple types of requests
 549  */
 550
 551 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 552                                  struct winbindd_request *request)
 553 {
 554         struct winbindd_request lrequest;
 555
 556         /* Check for our tricky environment variable */
 557
 558         if (winbind_env_set()) {
 559                 return NSS_STATUS_NOTFOUND;
 560         }
 561
 562         if (!request) {
 563                 ZERO_STRUCT(lrequest);
 564                 request = &lrequest;
 565         }
 566
 567         /* Fill in request and send down pipe */
 568
 569         init_request(request, req_type);
 570
 571         if (write_sock(request, sizeof(*request),
 572                        request->flags & WBFLAG_RECURSE, need_priv) == -1) {
 573                 return NSS_STATUS_UNAVAIL;
 574         }
 575
 576         if ((request->extra_len != 0) &&
 577             (write_sock(request->extra_data.data, request->extra_len,
 578                         request->flags & WBFLAG_RECURSE, need_priv) == -1)) {
 579                 return NSS_STATUS_UNAVAIL;
 580         }
 581
 582         return NSS_STATUS_SUCCESS;
 583 }
 584
 585 /*
 586  * Get results from winbindd request
 587  */
 588
 589 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 590 {
 591         struct winbindd_response lresponse;
 592
 593         if (!response) {
 594                 ZERO_STRUCT(lresponse);
 595                 response = &lresponse;
 596         }
 597
 598         init_response(response);
 599
 600         /* Wait for reply */
 601         if (read_reply(response) == -1) {
 602                 return NSS_STATUS_UNAVAIL;
 603         }
 604
 605         /* Throw away extra data if client didn't request it */
 606         if (response == &lresponse) {
 607                 free_response(response);
 608         }
 609
 610         /* Copy reply data from socket */
 611         if (response->result != WINBINDD_OK) {
 612                 return NSS_STATUS_NOTFOUND;
 613         }
 614
 615         return NSS_STATUS_SUCCESS;
 616 }
 617
 618 /* Handle simple types of requests */
 619
 620 NSS_STATUS winbindd_request_response(int req_type,
 621                             struct winbindd_request *request,
 622                             struct winbindd_response *response)
 623 {
 624         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 625         int count = 0;
 626
 627         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 628                 status = winbindd_send_request(req_type, 0, request);
 629                 if (status != NSS_STATUS_SUCCESS)
 630                         return(status);
 631                 status = winbindd_get_response(response);
 632                 count += 1;
 633         }
 634
 635         return status;
 636 }
 637
 638 NSS_STATUS winbindd_priv_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, 1, 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 /*************************************************************************
 657  A couple of simple functions to disable winbindd lookups and re-
 658  enable them
 659  ************************************************************************/
 660
 661 /* Use putenv() instead of setenv() in these functions as not all
 662    environments have the latter. */
 663
 664 BOOL winbind_off( void )
 665 {
 666         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=1");
 667
 668         return putenv(s) != -1;
 669 }
 670
 671 BOOL winbind_on( void )
 672 {
 673         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=0");
 674
 675         return putenv(s) != -1;
 676 }
 677