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