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 Lesser General Public
  13    License as published by the Free Software Foundation; either
  14    version 3 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 Lesser General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "winbind_client.h"
  26
  27 /* Global variables.  These are effectively the client state information */
  28
  29 int winbindd_fd = -1;           /* fd for winbindd socket */
  30 static int is_privileged = 0;
  31
  32 /* Free a response structure */
  33
  34 void winbindd_free_response(struct winbindd_response *response)
  35 {
  36         /* Free any allocated extra_data */
  37
  38         if (response)
  39                 SAFE_FREE(response->extra_data.data);
  40 }
  41
  42 /* Initialise a request structure */
  43
  44 static void winbindd_init_request(struct winbindd_request *request,
  45                                   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 static 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 static void winbind_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
  75 /* Make sure socket handle isn't stdin, stdout or stderr */
  76 #define RECURSION_LIMIT 3
  77
  78 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  79 {
  80         int new_fd;
  81         if (fd >= 0 && fd <= 2) {
  82 #ifdef F_DUPFD
  83                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  84                         return -1;
  85                 }
  86                 /* Paranoia */
  87                 if (new_fd < 3) {
  88                         close(new_fd);
  89                         return -1;
  90                 }
  91                 close(fd);
  92                 return new_fd;
  93 #else
  94                 if (limit <= 0)
  95                         return -1;
  96
  97                 new_fd = dup(fd);
  98                 if (new_fd == -1)
  99                         return -1;
 100
 101                 /* use the program stack to hold our list of FDs to close */
 102                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 103                 close(fd);
 104                 return new_fd;
 105 #endif
 106         }
 107         return fd;
 108 }
 109
 110 /****************************************************************************
 111  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 112  else
 113  if SYSV use O_NDELAY
 114  if BSD use FNDELAY
 115  Set close on exec also.
 116 ****************************************************************************/
 117
 118 static int make_safe_fd(int fd)
 119 {
 120         int result, flags;
 121         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 122         if (new_fd == -1) {
 123                 close(fd);
 124                 return -1;
 125         }
 126
 127         /* Socket should be nonblocking. */
 128 #ifdef O_NONBLOCK
 129 #define FLAG_TO_SET O_NONBLOCK
 130 #else
 131 #ifdef SYSV
 132 #define FLAG_TO_SET O_NDELAY
 133 #else /* BSD */
 134 #define FLAG_TO_SET FNDELAY
 135 #endif
 136 #endif
 137
 138         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 139                 close(new_fd);
 140                 return -1;
 141         }
 142
 143         flags |= FLAG_TO_SET;
 144         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 145                 close(new_fd);
 146                 return -1;
 147         }
 148
 149 #undef FLAG_TO_SET
 150
 151         /* Socket should be closed on exec() */
 152 #ifdef FD_CLOEXEC
 153         result = flags = fcntl(new_fd, F_GETFD, 0);
 154         if (flags >= 0) {
 155                 flags |= FD_CLOEXEC;
 156                 result = fcntl( new_fd, F_SETFD, flags );
 157         }
 158         if (result < 0) {
 159                 close(new_fd);
 160                 return -1;
 161         }
 162 #endif
 163         return new_fd;
 164 }
 165
 166 /* Connect to winbindd socket */
 167
 168 static int winbind_named_pipe_sock(const char *dir)
 169 {
 170         struct sockaddr_un sunaddr;
 171         struct stat st;
 172         char *path = NULL;
 173         int fd;
 174         int wait_time;
 175         int slept;
 176
 177         /* Check permissions on unix socket directory */
 178
 179         if (lstat(dir, &st) == -1) {
 180                 errno = ENOENT;
 181                 return -1;
 182         }
 183
 184         if (!S_ISDIR(st.st_mode) ||
 185             (st.st_uid != 0 && st.st_uid != geteuid())) {
 186                 errno = ENOENT;
 187                 return -1;
 188         }
 189
 190         /* Connect to socket */
 191
 192         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 193                 return -1;
 194         }
 195
 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                 errno = ENOENT;
 206                 SAFE_FREE(path);
 207                 return -1;
 208         }
 209
 210         SAFE_FREE(path);
 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                 errno = ENOENT;
 216                 return -1;
 217         }
 218
 219         /* Connect to socket */
 220
 221         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 222                 return -1;
 223         }
 224
 225         /* Set socket non-blocking and close on exec. */
 226
 227         if ((fd = make_safe_fd( fd)) == -1) {
 228                 return fd;
 229         }
 230
 231         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 232                         wait_time += slept) {
 233                 struct timeval tv;
 234                 fd_set w_fds;
 235                 int ret;
 236                 int connect_errno = 0;
 237                 socklen_t 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 static const char *winbindd_socket_dir(void)
 286 {
 287 #ifdef SOCKET_WRAPPER
 288         const char *env_dir;
 289
 290         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 291         if (env_dir) {
 292                 return env_dir;
 293         }
 294 #endif
 295
 296         return WINBINDD_SOCKET_DIR;
 297 }
 298
 299 /* Connect to winbindd socket */
 300
 301 static int winbind_open_pipe_sock(int recursing, int need_priv)
 302 {
 303 #ifdef HAVE_UNIXSOCKET
 304         static pid_t our_pid;
 305         struct winbindd_request request;
 306         struct winbindd_response response;
 307         ZERO_STRUCT(request);
 308         ZERO_STRUCT(response);
 309
 310         if (our_pid != getpid()) {
 311                 winbind_close_sock();
 312                 our_pid = getpid();
 313         }
 314
 315         if ((need_priv != 0) && (is_privileged == 0)) {
 316                 winbind_close_sock();
 317         }
 318
 319         if (winbindd_fd != -1) {
 320                 return winbindd_fd;
 321         }
 322
 323         if (recursing) {
 324                 return -1;
 325         }
 326
 327         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 328                 return -1;
 329         }
 330
 331         is_privileged = 0;
 332
 333         /* version-check the socket */
 334
 335         request.wb_flags = WBFLAG_RECURSE;
 336         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 337                 winbind_close_sock();
 338                 return -1;
 339         }
 340
 341         /* try and get priv pipe */
 342
 343         request.wb_flags = WBFLAG_RECURSE;
 344         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 345                 int fd;
 346                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 347                         close(winbindd_fd);
 348                         winbindd_fd = fd;
 349                         is_privileged = 1;
 350                 }
 351         }
 352
 353         if ((need_priv != 0) && (is_privileged == 0)) {
 354                 return -1;
 355         }
 356
 357         SAFE_FREE(response.extra_data.data);
 358
 359         return winbindd_fd;
 360 #else
 361         return -1;
 362 #endif /* HAVE_UNIXSOCKET */
 363 }
 364
 365 /* Write data to winbindd socket */
 366
 367 static int winbind_write_sock(void *buffer, int count, int recursing,
 368                               int need_priv)
 369 {
 370         int result, nwritten;
 371
 372         /* Open connection to winbind daemon */
 373
 374  restart:
 375
 376         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 377                 errno = ENOENT;
 378                 return -1;
 379         }
 380
 381         /* Write data to socket */
 382
 383         nwritten = 0;
 384
 385         while(nwritten < count) {
 386                 struct timeval tv;
 387                 fd_set r_fds;
 388
 389                 /* Catch pipe close on other end by checking if a read()
 390                    call would not block by calling select(). */
 391
 392                 FD_ZERO(&r_fds);
 393                 FD_SET(winbindd_fd, &r_fds);
 394                 ZERO_STRUCT(tv);
 395
 396                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 397                         winbind_close_sock();
 398                         return -1;                   /* Select error */
 399                 }
 400
 401                 /* Write should be OK if fd not available for reading */
 402
 403                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 404
 405                         /* Do the write */
 406
 407                         result = write(winbindd_fd,
 408                                        (char *)buffer + nwritten,
 409                                        count - nwritten);
 410
 411                         if ((result == -1) || (result == 0)) {
 412
 413                                 /* Write failed */
 414
 415                                 winbind_close_sock();
 416                                 return -1;
 417                         }
 418
 419                         nwritten += result;
 420
 421                 } else {
 422
 423                         /* Pipe has closed on remote end */
 424
 425                         winbind_close_sock();
 426                         goto restart;
 427                 }
 428         }
 429
 430         return nwritten;
 431 }
 432
 433 /* Read data from winbindd socket */
 434
 435 static int winbind_read_sock(void *buffer, int count)
 436 {
 437         int nread = 0;
 438         int total_time = 0, selret;
 439
 440         if (winbindd_fd == -1) {
 441                 return -1;
 442         }
 443
 444         /* Read data from socket */
 445         while(nread < count) {
 446                 struct timeval tv;
 447                 fd_set r_fds;
 448
 449                 /* Catch pipe close on other end by checking if a read()
 450                    call would not block by calling select(). */
 451
 452                 FD_ZERO(&r_fds);
 453                 FD_SET(winbindd_fd, &r_fds);
 454                 ZERO_STRUCT(tv);
 455                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 456                 tv.tv_sec = 5;
 457
 458                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 459                         winbind_close_sock();
 460                         return -1;                   /* Select error */
 461                 }
 462
 463                 if (selret == 0) {
 464                         /* Not ready for read yet... */
 465                         if (total_time >= 30) {
 466                                 /* Timeout */
 467                                 winbind_close_sock();
 468                                 return -1;
 469                         }
 470                         total_time += 5;
 471                         continue;
 472                 }
 473
 474                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 475
 476                         /* Do the Read */
 477
 478                         int result = read(winbindd_fd, (char *)buffer + nread,
 479                               count - nread);
 480
 481                         if ((result == -1) || (result == 0)) {
 482
 483                                 /* Read failed.  I think the only useful thing we
 484                                    can do here is just return -1 and fail since the
 485                                    transaction has failed half way through. */
 486
 487                                 winbind_close_sock();
 488                                 return -1;
 489                         }
 490
 491                         nread += result;
 492
 493                 }
 494         }
 495
 496         return nread;
 497 }
 498
 499 /* Read reply */
 500
 501 static int winbindd_read_reply(struct winbindd_response *response)
 502 {
 503         int result1, result2 = 0;
 504
 505         if (!response) {
 506                 return -1;
 507         }
 508
 509         /* Read fixed length response */
 510
 511         result1 = winbind_read_sock(response,
 512                                     sizeof(struct winbindd_response));
 513         if (result1 == -1) {
 514                 return -1;
 515         }
 516
 517         /* We actually send the pointer value of the extra_data field from
 518            the server.  This has no meaning in the client's address space
 519            so we clear it out. */
 520
 521         response->extra_data.data = NULL;
 522
 523         /* Read variable length response */
 524
 525         if (response->length > sizeof(struct winbindd_response)) {
 526                 int extra_data_len = response->length -
 527                         sizeof(struct winbindd_response);
 528
 529                 /* Mallocate memory for extra data */
 530
 531                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 532                         return -1;
 533                 }
 534
 535                 result2 = winbind_read_sock(response->extra_data.data,
 536                                             extra_data_len);
 537                 if (result2 == -1) {
 538                         winbindd_free_response(response);
 539                         return -1;
 540                 }
 541         }
 542
 543         /* Return total amount of data read */
 544
 545         return result1 + result2;
 546 }
 547
 548 /*
 549  * send simple types of requests
 550  */
 551
 552 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 553                                  struct winbindd_request *request)
 554 {
 555         struct winbindd_request lrequest;
 556
 557         /* Check for our tricky environment variable */
 558
 559         if (winbind_env_set()) {
 560                 return NSS_STATUS_NOTFOUND;
 561         }
 562
 563         if (!request) {
 564                 ZERO_STRUCT(lrequest);
 565                 request = &lrequest;
 566         }
 567
 568         /* Fill in request and send down pipe */
 569
 570         winbindd_init_request(request, req_type);
 571
 572         if (winbind_write_sock(request, sizeof(*request),
 573                                request->wb_flags & WBFLAG_RECURSE,
 574                                need_priv) == -1)
 575         {
 576                 /* Set ENOENT for consistency.  Required by some apps */
 577                 errno = ENOENT;
 578
 579                 return NSS_STATUS_UNAVAIL;
 580         }
 581
 582         if ((request->extra_len != 0) &&
 583             (winbind_write_sock(request->extra_data.data,
 584                                 request->extra_len,
 585                                 request->wb_flags & WBFLAG_RECURSE,
 586                                 need_priv) == -1))
 587         {
 588                 /* Set ENOENT for consistency.  Required by some apps */
 589                 errno = ENOENT;
 590
 591                 return NSS_STATUS_UNAVAIL;
 592         }
 593
 594         return NSS_STATUS_SUCCESS;
 595 }
 596
 597 /*
 598  * Get results from winbindd request
 599  */
 600
 601 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 602 {
 603         struct winbindd_response lresponse;
 604
 605         if (!response) {
 606                 ZERO_STRUCT(lresponse);
 607                 response = &lresponse;
 608         }
 609
 610         init_response(response);
 611
 612         /* Wait for reply */
 613         if (winbindd_read_reply(response) == -1) {
 614                 /* Set ENOENT for consistency.  Required by some apps */
 615                 errno = ENOENT;
 616
 617                 return NSS_STATUS_UNAVAIL;
 618         }
 619
 620         /* Throw away extra data if client didn't request it */
 621         if (response == &lresponse) {
 622                 winbindd_free_response(response);
 623         }
 624
 625         /* Copy reply data from socket */
 626         if (response->result != WINBINDD_OK) {
 627                 return NSS_STATUS_NOTFOUND;
 628         }
 629
 630         return NSS_STATUS_SUCCESS;
 631 }
 632
 633 /* Handle simple types of requests */
 634
 635 NSS_STATUS winbindd_request_response(int req_type,
 636                             struct winbindd_request *request,
 637                             struct winbindd_response *response)
 638 {
 639         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 640         int count = 0;
 641
 642         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 643                 status = winbindd_send_request(req_type, 0, request);
 644                 if (status != NSS_STATUS_SUCCESS)
 645                         return(status);
 646                 status = winbindd_get_response(response);
 647                 count += 1;
 648         }
 649
 650         return status;
 651 }
 652
 653 NSS_STATUS winbindd_priv_request_response(int req_type,
 654                                           struct winbindd_request *request,
 655                                           struct winbindd_response *response)
 656 {
 657         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 658         int count = 0;
 659
 660         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 661                 status = winbindd_send_request(req_type, 1, request);
 662                 if (status != NSS_STATUS_SUCCESS)
 663                         return(status);
 664                 status = winbindd_get_response(response);
 665                 count += 1;
 666         }
 667
 668         return status;
 669 }