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 #define UID_WRAPPER_NOT_REPLACE
  26
  27 #include "replace.h"
  28 #include "system/select.h"
  29 #include "winbind_client.h"
  30
  31 /* Global variables.  These are effectively the client state information */
  32
  33 int winbindd_fd = -1;           /* fd for winbindd socket */
  34 static int is_privileged = 0;
  35
  36 /* Free a response structure */
  37
  38 void winbindd_free_response(struct winbindd_response *response)
  39 {
  40         /* Free any allocated extra_data */
  41
  42         if (response)
  43                 SAFE_FREE(response->extra_data.data);
  44 }
  45
  46 /* Initialise a request structure */
  47
  48 static void winbindd_init_request(struct winbindd_request *request,
  49                                   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 #if HAVE_FUNCTION_ATTRIBUTE_DESTRUCTOR
  70 __attribute__((destructor))
  71 #endif
  72 static void winbind_close_sock(void)
  73 {
  74         if (winbindd_fd != -1) {
  75                 close(winbindd_fd);
  76                 winbindd_fd = -1;
  77         }
  78 }
  79
  80 #define CONNECT_TIMEOUT 30
  81
  82 /* Make sure socket handle isn't stdin, stdout or stderr */
  83 #define RECURSION_LIMIT 3
  84
  85 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  86 {
  87         int new_fd;
  88         if (fd >= 0 && fd <= 2) {
  89 #ifdef F_DUPFD
  90                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  91                         return -1;
  92                 }
  93                 /* Paranoia */
  94                 if (new_fd < 3) {
  95                         close(new_fd);
  96                         return -1;
  97                 }
  98                 close(fd);
  99                 return new_fd;
 100 #else
 101                 if (limit <= 0)
 102                         return -1;
 103
 104                 new_fd = dup(fd);
 105                 if (new_fd == -1)
 106                         return -1;
 107
 108                 /* use the program stack to hold our list of FDs to close */
 109                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 110                 close(fd);
 111                 return new_fd;
 112 #endif
 113         }
 114         return fd;
 115 }
 116
 117 /****************************************************************************
 118  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 119  else
 120  if SYSV use O_NDELAY
 121  if BSD use FNDELAY
 122  Set close on exec also.
 123 ****************************************************************************/
 124
 125 static int make_safe_fd(int fd)
 126 {
 127         int result, flags;
 128         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 129         if (new_fd == -1) {
 130                 close(fd);
 131                 return -1;
 132         }
 133
 134         /* Socket should be nonblocking. */
 135 #ifdef O_NONBLOCK
 136 #define FLAG_TO_SET O_NONBLOCK
 137 #else
 138 #ifdef SYSV
 139 #define FLAG_TO_SET O_NDELAY
 140 #else /* BSD */
 141 #define FLAG_TO_SET FNDELAY
 142 #endif
 143 #endif
 144
 145         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 146                 close(new_fd);
 147                 return -1;
 148         }
 149
 150         flags |= FLAG_TO_SET;
 151         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 152                 close(new_fd);
 153                 return -1;
 154         }
 155
 156 #undef FLAG_TO_SET
 157
 158         /* Socket should be closed on exec() */
 159 #ifdef FD_CLOEXEC
 160         result = flags = fcntl(new_fd, F_GETFD, 0);
 161         if (flags >= 0) {
 162                 flags |= FD_CLOEXEC;
 163                 result = fcntl( new_fd, F_SETFD, flags );
 164         }
 165         if (result < 0) {
 166                 close(new_fd);
 167                 return -1;
 168         }
 169 #endif
 170         return new_fd;
 171 }
 172
 173 /* Connect to winbindd socket */
 174
 175 static int winbind_named_pipe_sock(const char *dir)
 176 {
 177         struct sockaddr_un sunaddr;
 178         struct stat st;
 179         char *path = NULL;
 180         int fd;
 181         int wait_time;
 182         int slept;
 183
 184         /* Check permissions on unix socket directory */
 185
 186         if (lstat(dir, &st) == -1) {
 187                 errno = ENOENT;
 188                 return -1;
 189         }
 190
 191         if (!S_ISDIR(st.st_mode) ||
 192             (st.st_uid != 0 && st.st_uid != geteuid())) {
 193                 errno = ENOENT;
 194                 return -1;
 195         }
 196
 197         /* Connect to socket */
 198
 199         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 200                 return -1;
 201         }
 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                 errno = ENOENT;
 213                 SAFE_FREE(path);
 214                 return -1;
 215         }
 216
 217         SAFE_FREE(path);
 218         /* Check permissions on unix socket file */
 219
 220         if (!S_ISSOCK(st.st_mode) ||
 221             (st.st_uid != 0 && st.st_uid != geteuid())) {
 222                 errno = ENOENT;
 223                 return -1;
 224         }
 225
 226         /* Connect to socket */
 227
 228         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 229                 return -1;
 230         }
 231
 232         /* Set socket non-blocking and close on exec. */
 233
 234         if ((fd = make_safe_fd( fd)) == -1) {
 235                 return fd;
 236         }
 237
 238         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 239                         wait_time += slept) {
 240                 struct pollfd pfd;
 241                 int ret;
 242                 int connect_errno = 0;
 243                 socklen_t errnosize;
 244
 245                 if (wait_time >= CONNECT_TIMEOUT)
 246                         goto error_out;
 247
 248                 switch (errno) {
 249                         case EINPROGRESS:
 250                                 pfd.fd = fd;
 251                                 pfd.events = POLLOUT;
 252
 253                                 ret = poll(&pfd, 1, (CONNECT_TIMEOUT - wait_time) * 1000);
 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 static const char *winbindd_socket_dir(void)
 290 {
 291 #ifdef SOCKET_WRAPPER
 292         const char *env_dir;
 293
 294         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 295         if (env_dir) {
 296                 return env_dir;
 297         }
 298 #endif
 299
 300         return WINBINDD_SOCKET_DIR;
 301 }
 302
 303 /* Connect to winbindd socket */
 304
 305 static int winbind_open_pipe_sock(int recursing, int need_priv)
 306 {
 307 #ifdef HAVE_UNIXSOCKET
 308         static pid_t our_pid;
 309         struct winbindd_request request;
 310         struct winbindd_response response;
 311         ZERO_STRUCT(request);
 312         ZERO_STRUCT(response);
 313
 314         if (our_pid != getpid()) {
 315                 winbind_close_sock();
 316                 our_pid = getpid();
 317         }
 318
 319         if ((need_priv != 0) && (is_privileged == 0)) {
 320                 winbind_close_sock();
 321         }
 322
 323         if (winbindd_fd != -1) {
 324                 return winbindd_fd;
 325         }
 326
 327         if (recursing) {
 328                 return -1;
 329         }
 330
 331         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 332                 return -1;
 333         }
 334
 335         is_privileged = 0;
 336
 337         /* version-check the socket */
 338
 339         request.wb_flags = WBFLAG_RECURSE;
 340         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 341                 winbind_close_sock();
 342                 return -1;
 343         }
 344
 345         /* try and get priv pipe */
 346
 347         request.wb_flags = WBFLAG_RECURSE;
 348         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 349                 int fd;
 350                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 351                         close(winbindd_fd);
 352                         winbindd_fd = fd;
 353                         is_privileged = 1;
 354                 }
 355         }
 356
 357         if ((need_priv != 0) && (is_privileged == 0)) {
 358                 return -1;
 359         }
 360
 361         SAFE_FREE(response.extra_data.data);
 362
 363         return winbindd_fd;
 364 #else
 365         return -1;
 366 #endif /* HAVE_UNIXSOCKET */
 367 }
 368
 369 /* Write data to winbindd socket */
 370
 371 static int winbind_write_sock(void *buffer, int count, int recursing,
 372                               int need_priv)
 373 {
 374         int fd, result, nwritten;
 375
 376         /* Open connection to winbind daemon */
 377
 378  restart:
 379
 380         fd = winbind_open_pipe_sock(recursing, need_priv);
 381         if (fd == -1) {
 382                 errno = ENOENT;
 383                 return -1;
 384         }
 385
 386         /* Write data to socket */
 387
 388         nwritten = 0;
 389
 390         while(nwritten < count) {
 391                 struct pollfd pfd;
 392                 int ret;
 393
 394                 /* Catch pipe close on other end by checking if a read()
 395                    call would not block by calling poll(). */
 396
 397                 pfd.fd = fd;
 398                 pfd.events = POLLIN|POLLHUP;
 399
 400                 ret = poll(&pfd, 1, 0);
 401                 if (ret == -1) {
 402                         winbind_close_sock();
 403                         return -1;                   /* poll error */
 404                 }
 405
 406                 /* Write should be OK if fd not available for reading */
 407
 408                 if ((ret == 1) && (pfd.revents & (POLLIN|POLLHUP|POLLERR))) {
 409
 410                         /* Pipe has closed on remote end */
 411
 412                         winbind_close_sock();
 413                         goto restart;
 414                 }
 415
 416                 /* Do the write */
 417
 418                 result = write(fd, (char *)buffer + nwritten,
 419                                count - nwritten);
 420
 421                 if ((result == -1) || (result == 0)) {
 422
 423                         /* Write failed */
 424
 425                         winbind_close_sock();
 426                         return -1;
 427                 }
 428
 429                 nwritten += result;
 430         }
 431
 432         return nwritten;
 433 }
 434
 435 /* Read data from winbindd socket */
 436
 437 static int winbind_read_sock(void *buffer, int count)
 438 {
 439         int fd;
 440         int nread = 0;
 441         int total_time = 0;
 442
 443         fd = winbind_open_pipe_sock(false, false);
 444         if (fd == -1) {
 445                 return -1;
 446         }
 447
 448         /* Read data from socket */
 449         while(nread < count) {
 450                 struct pollfd pfd;
 451                 int ret;
 452
 453                 /* Catch pipe close on other end by checking if a read()
 454                    call would not block by calling poll(). */
 455
 456                 pfd.fd = fd;
 457                 pfd.events = POLLIN|POLLHUP;
 458
 459                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 460
 461                 ret = poll(&pfd, 1, 5000);
 462                 if (ret == -1) {
 463                         winbind_close_sock();
 464                         return -1;                   /* poll error */
 465                 }
 466
 467                 if (ret == 0) {
 468                         /* Not ready for read yet... */
 469                         if (total_time >= 30) {
 470                                 /* Timeout */
 471                                 winbind_close_sock();
 472                                 return -1;
 473                         }
 474                         total_time += 5;
 475                         continue;
 476                 }
 477
 478                 if ((ret == 1) && (pfd.revents & (POLLIN|POLLHUP|POLLERR))) {
 479
 480                         /* Do the Read */
 481
 482                         int result = read(fd, (char *)buffer + nread,
 483                               count - nread);
 484
 485                         if ((result == -1) || (result == 0)) {
 486
 487                                 /* Read failed.  I think the only useful thing we
 488                                    can do here is just return -1 and fail since the
 489                                    transaction has failed half way through. */
 490
 491                                 winbind_close_sock();
 492                                 return -1;
 493                         }
 494
 495                         nread += result;
 496
 497                 }
 498         }
 499
 500         return nread;
 501 }
 502
 503 /* Read reply */
 504
 505 static int winbindd_read_reply(struct winbindd_response *response)
 506 {
 507         int result1, result2 = 0;
 508
 509         if (!response) {
 510                 return -1;
 511         }
 512
 513         /* Read fixed length response */
 514
 515         result1 = winbind_read_sock(response,
 516                                     sizeof(struct winbindd_response));
 517         if (result1 == -1) {
 518                 return -1;
 519         }
 520
 521         if (response->length < sizeof(struct winbindd_response)) {
 522                 return -1;
 523         }
 524
 525         /* We actually send the pointer value of the extra_data field from
 526            the server.  This has no meaning in the client's address space
 527            so we clear it out. */
 528
 529         response->extra_data.data = NULL;
 530
 531         /* Read variable length response */
 532
 533         if (response->length > sizeof(struct winbindd_response)) {
 534                 int extra_data_len = response->length -
 535                         sizeof(struct winbindd_response);
 536
 537                 /* Mallocate memory for extra data */
 538
 539                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 540                         return -1;
 541                 }
 542
 543                 result2 = winbind_read_sock(response->extra_data.data,
 544                                             extra_data_len);
 545                 if (result2 == -1) {
 546                         winbindd_free_response(response);
 547                         return -1;
 548                 }
 549         }
 550
 551         /* Return total amount of data read */
 552
 553         return result1 + result2;
 554 }
 555
 556 /*
 557  * send simple types of requests
 558  */
 559
 560 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 561                                  struct winbindd_request *request)
 562 {
 563         struct winbindd_request lrequest;
 564
 565         /* Check for our tricky environment variable */
 566
 567         if (winbind_env_set()) {
 568                 return NSS_STATUS_NOTFOUND;
 569         }
 570
 571         if (!request) {
 572                 ZERO_STRUCT(lrequest);
 573                 request = &lrequest;
 574         }
 575
 576         /* Fill in request and send down pipe */
 577
 578         winbindd_init_request(request, req_type);
 579
 580         if (winbind_write_sock(request, sizeof(*request),
 581                                request->wb_flags & WBFLAG_RECURSE,
 582                                need_priv) == -1)
 583         {
 584                 /* Set ENOENT for consistency.  Required by some apps */
 585                 errno = ENOENT;
 586
 587                 return NSS_STATUS_UNAVAIL;
 588         }
 589
 590         if ((request->extra_len != 0) &&
 591             (winbind_write_sock(request->extra_data.data,
 592                                 request->extra_len,
 593                                 request->wb_flags & WBFLAG_RECURSE,
 594                                 need_priv) == -1))
 595         {
 596                 /* Set ENOENT for consistency.  Required by some apps */
 597                 errno = ENOENT;
 598
 599                 return NSS_STATUS_UNAVAIL;
 600         }
 601
 602         return NSS_STATUS_SUCCESS;
 603 }
 604
 605 /*
 606  * Get results from winbindd request
 607  */
 608
 609 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 610 {
 611         struct winbindd_response lresponse;
 612
 613         if (!response) {
 614                 ZERO_STRUCT(lresponse);
 615                 response = &lresponse;
 616         }
 617
 618         init_response(response);
 619
 620         /* Wait for reply */
 621         if (winbindd_read_reply(response) == -1) {
 622                 /* Set ENOENT for consistency.  Required by some apps */
 623                 errno = ENOENT;
 624
 625                 return NSS_STATUS_UNAVAIL;
 626         }
 627
 628         /* Throw away extra data if client didn't request it */
 629         if (response == &lresponse) {
 630                 winbindd_free_response(response);
 631         }
 632
 633         /* Copy reply data from socket */
 634         if (response->result != WINBINDD_OK) {
 635                 return NSS_STATUS_NOTFOUND;
 636         }
 637
 638         return NSS_STATUS_SUCCESS;
 639 }
 640
 641 /* Handle simple types of requests */
 642
 643 NSS_STATUS winbindd_request_response(int req_type,
 644                             struct winbindd_request *request,
 645                             struct winbindd_response *response)
 646 {
 647         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 648         int count = 0;
 649
 650         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 651                 status = winbindd_send_request(req_type, 0, request);
 652                 if (status != NSS_STATUS_SUCCESS)
 653                         return(status);
 654                 status = winbindd_get_response(response);
 655                 count += 1;
 656         }
 657
 658         return status;
 659 }
 660
 661 NSS_STATUS winbindd_priv_request_response(int req_type,
 662                                           struct winbindd_request *request,
 663                                           struct winbindd_response *response)
 664 {
 665         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 666         int count = 0;
 667
 668         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 669                 status = winbindd_send_request(req_type, 1, request);
 670                 if (status != NSS_STATUS_SUCCESS)
 671                         return(status);
 672                 status = winbindd_get_response(response);
 673                 count += 1;
 674         }
 675
 676         return status;
 677 }