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 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
  37 /* Free a response structure */
  38
  39 void free_response(struct winbindd_response *response)
  40 {
  41         /* Free any allocated extra_data */
  42
  43         if (response)
  44                 SAFE_FREE(response->extra_data.data);
  45 }
  46
  47 /* Initialise a request structure */
  48
  49 void init_request(struct winbindd_request *request, int request_type)
  50 {
  51         request->length = sizeof(struct winbindd_request);
  52
  53         request->cmd = (enum winbindd_cmd)request_type;
  54         request->pid = getpid();
  55
  56 }
  57
  58 /* Initialise a response structure */
  59
  60 static void init_response(struct winbindd_response *response)
  61 {
  62         /* Initialise return value */
  63
  64         response->result = WINBINDD_ERROR;
  65 }
  66
  67 /* Close established socket */
  68
  69 void close_sock(void)
  70 {
  71         if (winbindd_fd != -1) {
  72                 close(winbindd_fd);
  73                 winbindd_fd = -1;
  74         }
  75 }
  76
  77 #define CONNECT_TIMEOUT 30
  78
  79 /* Make sure socket handle isn't stdin, stdout or stderr */
  80 #define RECURSION_LIMIT 3
  81
  82 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  83 {
  84         int new_fd;
  85         if (fd >= 0 && fd <= 2) {
  86 #ifdef F_DUPFD
  87                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  88                         return -1;
  89                 }
  90                 /* Paranoia */
  91                 if (new_fd < 3) {
  92                         close(new_fd);
  93                         return -1;
  94                 }
  95                 close(fd);
  96                 return new_fd;
  97 #else
  98                 if (limit <= 0)
  99                         return -1;
 100
 101                 new_fd = dup(fd);
 102                 if (new_fd == -1)
 103                         return -1;
 104
 105                 /* use the program stack to hold our list of FDs to close */
 106                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 107                 close(fd);
 108                 return new_fd;
 109 #endif
 110         }
 111         return fd;
 112 }
 113
 114 /****************************************************************************
 115  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 116  else
 117  if SYSV use O_NDELAY
 118  if BSD use FNDELAY
 119  Set close on exec also.
 120 ****************************************************************************/
 121
 122 static int make_safe_fd(int fd)
 123 {
 124         int result, flags;
 125         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 126         if (new_fd == -1) {
 127                 close(fd);
 128                 return -1;
 129         }
 130
 131         /* Socket should be nonblocking. */
 132 #ifdef O_NONBLOCK
 133 #define FLAG_TO_SET O_NONBLOCK
 134 #else
 135 #ifdef SYSV
 136 #define FLAG_TO_SET O_NDELAY
 137 #else /* BSD */
 138 #define FLAG_TO_SET FNDELAY
 139 #endif
 140 #endif
 141
 142         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 143                 close(new_fd);
 144                 return -1;
 145         }
 146
 147         flags |= FLAG_TO_SET;
 148         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 149                 close(new_fd);
 150                 return -1;
 151         }
 152
 153 #undef FLAG_TO_SET
 154
 155         /* Socket should be closed on exec() */
 156 #ifdef FD_CLOEXEC
 157         result = flags = fcntl(new_fd, F_GETFD, 0);
 158         if (flags >= 0) {
 159                 flags |= FD_CLOEXEC;
 160                 result = fcntl( new_fd, F_SETFD, flags );
 161         }
 162         if (result < 0) {
 163                 close(new_fd);
 164                 return -1;
 165         }
 166 #endif
 167         return new_fd;
 168 }
 169
 170 /* Connect to winbindd socket */
 171
 172 static int winbind_named_pipe_sock(const char *dir)
 173 {
 174         struct sockaddr_un sunaddr;
 175         struct stat st;
 176         pstring path;
 177         int fd;
 178         int wait_time;
 179         int slept;
 180
 181         /* Check permissions on unix socket directory */
 182
 183         if (lstat(dir, &st) == -1) {
 184                 return -1;
 185         }
 186
 187         if (!S_ISDIR(st.st_mode) ||
 188             (st.st_uid != 0 && st.st_uid != geteuid())) {
 189                 return -1;
 190         }
 191
 192         /* Connect to socket */
 193
 194         strncpy(path, dir, sizeof(path) - 1);
 195         path[sizeof(path) - 1] = '\0';
 196
 197         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 198         path[sizeof(path) - 1] = '\0';
 199
 200         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 201         path[sizeof(path) - 1] = '\0';
 202
 203         ZERO_STRUCT(sunaddr);
 204         sunaddr.sun_family = AF_UNIX;
 205         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 206
 207         /* If socket file doesn't exist, don't bother trying to connect
 208            with retry.  This is an attempt to make the system usable when
 209            the winbindd daemon is not running. */
 210
 211         if (lstat(path, &st) == -1) {
 212                 return -1;
 213         }
 214
 215         /* Check permissions on unix socket file */
 216
 217         if (!S_ISSOCK(st.st_mode) ||
 218             (st.st_uid != 0 && st.st_uid != geteuid())) {
 219                 return -1;
 220         }
 221
 222         /* Connect to socket */
 223
 224         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 225                 return -1;
 226         }
 227
 228         /* Set socket non-blocking and close on exec. */
 229
 230         if ((fd = make_safe_fd( fd)) == -1) {
 231                 return fd;
 232         }
 233
 234         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 235                         wait_time += slept) {
 236                 struct timeval tv;
 237                 fd_set w_fds;
 238                 int ret;
 239                 int connect_errno = 0;
 240                 socklen_t errnosize;
 241
 242                 if (wait_time >= CONNECT_TIMEOUT)
 243                         goto error_out;
 244
 245                 switch (errno) {
 246                         case EINPROGRESS:
 247                                 FD_ZERO(&w_fds);
 248                                 FD_SET(fd, &w_fds);
 249                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 250                                 tv.tv_usec = 0;
 251
 252                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 253
 254                                 if (ret > 0) {
 255                                         errnosize = sizeof(connect_errno);
 256
 257                                         ret = getsockopt(fd, SOL_SOCKET,
 258                                                         SO_ERROR, &connect_errno, &errnosize);
 259
 260                                         if (ret >= 0 && connect_errno == 0) {
 261                                                 /* Connect succeed */
 262                                                 goto out;
 263                                         }
 264                                 }
 265
 266                                 slept = CONNECT_TIMEOUT;
 267                                 break;
 268                         case EAGAIN:
 269                                 slept = rand() % 3 + 1;
 270                                 sleep(slept);
 271                                 break;
 272                         default:
 273                                 goto error_out;
 274                 }
 275
 276         }
 277
 278   out:
 279
 280         return fd;
 281
 282   error_out:
 283
 284         close(fd);
 285         return -1;
 286 }
 287
 288 /* Connect to winbindd socket */
 289
 290 static int winbind_open_pipe_sock(int recursing)
 291 {
 292 #ifdef HAVE_UNIXSOCKET
 293         static pid_t our_pid;
 294         struct winbindd_request request;
 295         struct winbindd_response response;
 296         ZERO_STRUCT(request);
 297         ZERO_STRUCT(response);
 298
 299         if (our_pid != getpid()) {
 300                 close_sock();
 301                 our_pid = getpid();
 302         }
 303
 304         if (winbindd_fd != -1) {
 305                 return winbindd_fd;
 306         }
 307
 308         if (recursing) {
 309                 return -1;
 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         request.flags = WBFLAG_RECURSE;
 319         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 320                 close_sock();
 321                 return -1;
 322         }
 323
 324         /* try and get priv pipe */
 325
 326         request.flags = WBFLAG_RECURSE;
 327         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 328                 int fd;
 329                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 330                         close(winbindd_fd);
 331                         winbindd_fd = fd;
 332                 }
 333         }
 334
 335         SAFE_FREE(response.extra_data.data);
 336
 337         return winbindd_fd;
 338 #else
 339         return -1;
 340 #endif /* HAVE_UNIXSOCKET */
 341 }
 342
 343 /* Write data to winbindd socket */
 344
 345 int write_sock(void *buffer, int count, int recursing)
 346 {
 347         int result, nwritten;
 348
 349         /* Open connection to winbind daemon */
 350
 351  restart:
 352
 353         if (winbind_open_pipe_sock(recursing) == -1) {
 354                 return -1;
 355         }
 356
 357         /* Write data to socket */
 358
 359         nwritten = 0;
 360
 361         while(nwritten < count) {
 362                 struct timeval tv;
 363                 fd_set r_fds;
 364
 365                 /* Catch pipe close on other end by checking if a read()
 366                    call would not block by calling select(). */
 367
 368                 FD_ZERO(&r_fds);
 369                 FD_SET(winbindd_fd, &r_fds);
 370                 ZERO_STRUCT(tv);
 371
 372                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 373                         close_sock();
 374                         return -1;                   /* Select error */
 375                 }
 376
 377                 /* Write should be OK if fd not available for reading */
 378
 379                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 380
 381                         /* Do the write */
 382
 383                         result = write(winbindd_fd,
 384                                        (char *)buffer + nwritten,
 385                                        count - nwritten);
 386
 387                         if ((result == -1) || (result == 0)) {
 388
 389                                 /* Write failed */
 390
 391                                 close_sock();
 392                                 return -1;
 393                         }
 394
 395                         nwritten += result;
 396
 397                 } else {
 398
 399                         /* Pipe has closed on remote end */
 400
 401                         close_sock();
 402                         goto restart;
 403                 }
 404         }
 405
 406         return nwritten;
 407 }
 408
 409 /* Read data from winbindd socket */
 410
 411 static int read_sock(void *buffer, int count)
 412 {
 413         int result = 0, nread = 0;
 414         int total_time = 0, selret;
 415
 416         if (winbindd_fd == -1) {
 417                 return -1;
 418         }
 419
 420         /* Read data from socket */
 421         while(nread < count) {
 422                 struct timeval tv;
 423                 fd_set r_fds;
 424
 425                 /* Catch pipe close on other end by checking if a read()
 426                    call would not block by calling select(). */
 427
 428                 FD_ZERO(&r_fds);
 429                 FD_SET(winbindd_fd, &r_fds);
 430                 ZERO_STRUCT(tv);
 431                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 432                 tv.tv_sec = 5;
 433
 434                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 435                         close_sock();
 436                         return -1;                   /* Select error */
 437                 }
 438
 439                 if (selret == 0) {
 440                         /* Not ready for read yet... */
 441                         if (total_time >= 30) {
 442                                 /* Timeout */
 443                                 close_sock();
 444                                 return -1;
 445                         }
 446                         total_time += 5;
 447                         continue;
 448                 }
 449
 450                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 451
 452                         /* Do the Read */
 453
 454                         result = read(winbindd_fd, (char *)buffer + nread,
 455                               count - nread);
 456
 457                         if ((result == -1) || (result == 0)) {
 458
 459                                 /* Read failed.  I think the only useful thing we
 460                                    can do here is just return -1 and fail since the
 461                                    transaction has failed half way through. */
 462
 463                                 close_sock();
 464                                 return -1;
 465                         }
 466
 467                         nread += result;
 468
 469                 }
 470         }
 471
 472         return result;
 473 }
 474
 475 /* Read reply */
 476
 477 int read_reply(struct winbindd_response *response)
 478 {
 479         int result1, result2 = 0;
 480
 481         if (!response) {
 482                 return -1;
 483         }
 484
 485         /* Read fixed length response */
 486
 487         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 488             == -1) {
 489
 490                 return -1;
 491         }
 492
 493         /* We actually send the pointer value of the extra_data field from
 494            the server.  This has no meaning in the client's address space
 495            so we clear it out. */
 496
 497         response->extra_data.data = NULL;
 498
 499         /* Read variable length response */
 500
 501         if (response->length > sizeof(struct winbindd_response)) {
 502                 int extra_data_len = response->length -
 503                         sizeof(struct winbindd_response);
 504
 505                 /* Mallocate memory for extra data */
 506
 507                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 508                         return -1;
 509                 }
 510
 511                 if ((result2 = read_sock(response->extra_data.data, extra_data_len))
 512                     == -1) {
 513                         free_response(response);
 514                         return -1;
 515                 }
 516         }
 517
 518         /* Return total amount of data read */
 519
 520         return result1 + result2;
 521 }
 522
 523 BOOL winbind_env_set( void )
 524 {
 525         char *env;
 526
 527         if ((env=getenv(WINBINDD_DONT_ENV)) != NULL) {
 528                 if(strcmp(env, "1") == 0) {
 529                         return True;
 530                 }
 531         }
 532         return False;
 533 }
 534
 535 /*
 536  * send simple types of requests
 537  */
 538
 539 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 540 {
 541         struct winbindd_request lrequest;
 542
 543         /* Check for our tricky environment variable */
 544
 545         if (winbind_env_set()) {
 546                 return NSS_STATUS_NOTFOUND;
 547         }
 548
 549         if (!request) {
 550                 ZERO_STRUCT(lrequest);
 551                 request = &lrequest;
 552         }
 553
 554         /* Fill in request and send down pipe */
 555
 556         init_request(request, req_type);
 557
 558         if (write_sock(request, sizeof(*request), request->flags & WBFLAG_RECURSE) == -1) {
 559                 return NSS_STATUS_UNAVAIL;
 560         }
 561
 562         if ((request->extra_len != 0) &&
 563             (write_sock(request->extra_data.data, request->extra_len, request->flags & WBFLAG_RECURSE) == -1)) {
 564                 return NSS_STATUS_UNAVAIL;
 565         }
 566
 567         return NSS_STATUS_SUCCESS;
 568 }
 569
 570 /*
 571  * Get results from winbindd request
 572  */
 573
 574 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 575 {
 576         struct winbindd_response lresponse;
 577
 578         if (!response) {
 579                 ZERO_STRUCT(lresponse);
 580                 response = &lresponse;
 581         }
 582
 583         init_response(response);
 584
 585         /* Wait for reply */
 586         if (read_reply(response) == -1) {
 587                 return NSS_STATUS_UNAVAIL;
 588         }
 589
 590         /* Throw away extra data if client didn't request it */
 591         if (response == &lresponse) {
 592                 free_response(response);
 593         }
 594
 595         /* Copy reply data from socket */
 596         if (response->result != WINBINDD_OK) {
 597                 return NSS_STATUS_NOTFOUND;
 598         }
 599
 600         return NSS_STATUS_SUCCESS;
 601 }
 602
 603 /* Handle simple types of requests */
 604
 605 NSS_STATUS winbindd_request_response(int req_type,
 606                             struct winbindd_request *request,
 607                             struct winbindd_response *response)
 608 {
 609         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 610         int count = 0;
 611
 612         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 613                 status = winbindd_send_request(req_type, request);
 614                 if (status != NSS_STATUS_SUCCESS)
 615                         return(status);
 616                 status = winbindd_get_response(response);
 617                 count += 1;
 618         }
 619
 620         return status;
 621 }
 622
 623 /*************************************************************************
 624  A couple of simple functions to disable winbindd lookups and re-
 625  enable them
 626  ************************************************************************/
 627
 628 /* Use putenv() instead of setenv() in these functions as not all
 629    environments have the latter. */
 630
 631 BOOL winbind_off( void )
 632 {
 633         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=1");
 634
 635         return putenv(s) != -1;
 636 }
 637
 638 BOOL winbind_on( void )
 639 {
 640         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=0");
 641
 642         return putenv(s) != -1;
 643 }
 644