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 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 void winbindd_init_request(struct winbindd_request *request, int request_type)
  45 {
  46         request->length = sizeof(struct winbindd_request);
  47
  48         request->cmd = (enum winbindd_cmd)request_type;
  49         request->pid = getpid();
  50
  51 }
  52
  53 /* Initialise a response structure */
  54
  55 static void init_response(struct winbindd_response *response)
  56 {
  57         /* Initialise return value */
  58
  59         response->result = WINBINDD_ERROR;
  60 }
  61
  62 /* Close established socket */
  63
  64 void winbind_close_sock(void)
  65 {
  66         if (winbindd_fd != -1) {
  67                 close(winbindd_fd);
  68                 winbindd_fd = -1;
  69         }
  70 }
  71
  72 #define CONNECT_TIMEOUT 30
  73
  74 /* Make sure socket handle isn't stdin, stdout or stderr */
  75 #define RECURSION_LIMIT 3
  76
  77 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  78 {
  79         int new_fd;
  80         if (fd >= 0 && fd <= 2) {
  81 #ifdef F_DUPFD
  82                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  83                         return -1;
  84                 }
  85                 /* Paranoia */
  86                 if (new_fd < 3) {
  87                         close(new_fd);
  88                         return -1;
  89                 }
  90                 close(fd);
  91                 return new_fd;
  92 #else
  93                 if (limit <= 0)
  94                         return -1;
  95
  96                 new_fd = dup(fd);
  97                 if (new_fd == -1)
  98                         return -1;
  99
 100                 /* use the program stack to hold our list of FDs to close */
 101                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 102                 close(fd);
 103                 return new_fd;
 104 #endif
 105         }
 106         return fd;
 107 }
 108
 109 /****************************************************************************
 110  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 111  else
 112  if SYSV use O_NDELAY
 113  if BSD use FNDELAY
 114  Set close on exec also.
 115 ****************************************************************************/
 116
 117 static int make_safe_fd(int fd)
 118 {
 119         int result, flags;
 120         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 121         if (new_fd == -1) {
 122                 close(fd);
 123                 return -1;
 124         }
 125
 126         /* Socket should be nonblocking. */
 127 #ifdef O_NONBLOCK
 128 #define FLAG_TO_SET O_NONBLOCK
 129 #else
 130 #ifdef SYSV
 131 #define FLAG_TO_SET O_NDELAY
 132 #else /* BSD */
 133 #define FLAG_TO_SET FNDELAY
 134 #endif
 135 #endif
 136
 137         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 138                 close(new_fd);
 139                 return -1;
 140         }
 141
 142         flags |= FLAG_TO_SET;
 143         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 144                 close(new_fd);
 145                 return -1;
 146         }
 147
 148 #undef FLAG_TO_SET
 149
 150         /* Socket should be closed on exec() */
 151 #ifdef FD_CLOEXEC
 152         result = flags = fcntl(new_fd, F_GETFD, 0);
 153         if (flags >= 0) {
 154                 flags |= FD_CLOEXEC;
 155                 result = fcntl( new_fd, F_SETFD, flags );
 156         }
 157         if (result < 0) {
 158                 close(new_fd);
 159                 return -1;
 160         }
 161 #endif
 162         return new_fd;
 163 }
 164
 165 /* Connect to winbindd socket */
 166
 167 static int winbind_named_pipe_sock(const char *dir)
 168 {
 169         struct sockaddr_un sunaddr;
 170         struct stat st;
 171         char *path = NULL;
 172         int fd;
 173         int wait_time;
 174         int slept;
 175
 176         /* Check permissions on unix socket directory */
 177
 178         if (lstat(dir, &st) == -1) {
 179                 return -1;
 180         }
 181
 182         if (!S_ISDIR(st.st_mode) ||
 183             (st.st_uid != 0 && st.st_uid != geteuid())) {
 184                 return -1;
 185         }
 186
 187         /* Connect to socket */
 188
 189         if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
 190                 return -1;
 191         }
 192
 193         ZERO_STRUCT(sunaddr);
 194         sunaddr.sun_family = AF_UNIX;
 195         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 196
 197         /* If socket file doesn't exist, don't bother trying to connect
 198            with retry.  This is an attempt to make the system usable when
 199            the winbindd daemon is not running. */
 200
 201         if (lstat(path, &st) == -1) {
 202                 SAFE_FREE(path);
 203                 return -1;
 204         }
 205
 206         SAFE_FREE(path);
 207         /* Check permissions on unix socket file */
 208
 209         if (!S_ISSOCK(st.st_mode) ||
 210             (st.st_uid != 0 && st.st_uid != geteuid())) {
 211                 return -1;
 212         }
 213
 214         /* Connect to socket */
 215
 216         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 217                 return -1;
 218         }
 219
 220         /* Set socket non-blocking and close on exec. */
 221
 222         if ((fd = make_safe_fd( fd)) == -1) {
 223                 return fd;
 224         }
 225
 226         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 227                         wait_time += slept) {
 228                 struct timeval tv;
 229                 fd_set w_fds;
 230                 int ret;
 231                 int connect_errno = 0;
 232                 socklen_t errnosize;
 233
 234                 if (wait_time >= CONNECT_TIMEOUT)
 235                         goto error_out;
 236
 237                 switch (errno) {
 238                         case EINPROGRESS:
 239                                 FD_ZERO(&w_fds);
 240                                 FD_SET(fd, &w_fds);
 241                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 242                                 tv.tv_usec = 0;
 243
 244                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 245
 246                                 if (ret > 0) {
 247                                         errnosize = sizeof(connect_errno);
 248
 249                                         ret = getsockopt(fd, SOL_SOCKET,
 250                                                         SO_ERROR, &connect_errno, &errnosize);
 251
 252                                         if (ret >= 0 && connect_errno == 0) {
 253                                                 /* Connect succeed */
 254                                                 goto out;
 255                                         }
 256                                 }
 257
 258                                 slept = CONNECT_TIMEOUT;
 259                                 break;
 260                         case EAGAIN:
 261                                 slept = rand() % 3 + 1;
 262                                 sleep(slept);
 263                                 break;
 264                         default:
 265                                 goto error_out;
 266                 }
 267
 268         }
 269
 270   out:
 271
 272         return fd;
 273
 274   error_out:
 275
 276         close(fd);
 277         return -1;
 278 }
 279
 280 static const char *winbindd_socket_dir(void)
 281 {
 282 #ifdef SOCKET_WRAPPER
 283         const char *env_dir;
 284
 285         env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
 286         if (env_dir) {
 287                 return env_dir;
 288         }
 289 #endif
 290
 291         return WINBINDD_SOCKET_DIR;
 292 }
 293
 294 /* Connect to winbindd socket */
 295
 296 static int winbind_open_pipe_sock(int recursing, int need_priv)
 297 {
 298 #ifdef HAVE_UNIXSOCKET
 299         static pid_t our_pid;
 300         struct winbindd_request request;
 301         struct winbindd_response response;
 302         ZERO_STRUCT(request);
 303         ZERO_STRUCT(response);
 304
 305         if (our_pid != getpid()) {
 306                 winbind_close_sock();
 307                 our_pid = getpid();
 308         }
 309
 310         if ((need_priv != 0) && (is_privileged == 0)) {
 311                 winbind_close_sock();
 312         }
 313
 314         if (winbindd_fd != -1) {
 315                 return winbindd_fd;
 316         }
 317
 318         if (recursing) {
 319                 return -1;
 320         }
 321
 322         if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
 323                 return -1;
 324         }
 325
 326         is_privileged = 0;
 327
 328         /* version-check the socket */
 329
 330         request.wb_flags = WBFLAG_RECURSE;
 331         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 332                 winbind_close_sock();
 333                 return -1;
 334         }
 335
 336         /* try and get priv pipe */
 337
 338         request.wb_flags = WBFLAG_RECURSE;
 339         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 340                 int fd;
 341                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 342                         close(winbindd_fd);
 343                         winbindd_fd = fd;
 344                         is_privileged = 1;
 345                 }
 346         }
 347
 348         if ((need_priv != 0) && (is_privileged == 0)) {
 349                 return -1;
 350         }
 351
 352         SAFE_FREE(response.extra_data.data);
 353
 354         return winbindd_fd;
 355 #else
 356         return -1;
 357 #endif /* HAVE_UNIXSOCKET */
 358 }
 359
 360 /* Write data to winbindd socket */
 361
 362 int winbind_write_sock(void *buffer, int count, int recursing, int need_priv)
 363 {
 364         int result, nwritten;
 365
 366         /* Open connection to winbind daemon */
 367
 368  restart:
 369
 370         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 371                 return -1;
 372         }
 373
 374         /* Write data to socket */
 375
 376         nwritten = 0;
 377
 378         while(nwritten < count) {
 379                 struct timeval tv;
 380                 fd_set r_fds;
 381
 382                 /* Catch pipe close on other end by checking if a read()
 383                    call would not block by calling select(). */
 384
 385                 FD_ZERO(&r_fds);
 386                 FD_SET(winbindd_fd, &r_fds);
 387                 ZERO_STRUCT(tv);
 388
 389                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 390                         winbind_close_sock();
 391                         return -1;                   /* Select error */
 392                 }
 393
 394                 /* Write should be OK if fd not available for reading */
 395
 396                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 397
 398                         /* Do the write */
 399
 400                         result = write(winbindd_fd,
 401                                        (char *)buffer + nwritten,
 402                                        count - nwritten);
 403
 404                         if ((result == -1) || (result == 0)) {
 405
 406                                 /* Write failed */
 407
 408                                 winbind_close_sock();
 409                                 return -1;
 410                         }
 411
 412                         nwritten += result;
 413
 414                 } else {
 415
 416                         /* Pipe has closed on remote end */
 417
 418                         winbind_close_sock();
 419                         goto restart;
 420                 }
 421         }
 422
 423         return nwritten;
 424 }
 425
 426 /* Read data from winbindd socket */
 427
 428 int winbind_read_sock(void *buffer, int count)
 429 {
 430         int nread = 0;
 431         int total_time = 0, selret;
 432
 433         if (winbindd_fd == -1) {
 434                 return -1;
 435         }
 436
 437         /* Read data from socket */
 438         while(nread < count) {
 439                 struct timeval tv;
 440                 fd_set r_fds;
 441
 442                 /* Catch pipe close on other end by checking if a read()
 443                    call would not block by calling select(). */
 444
 445                 FD_ZERO(&r_fds);
 446                 FD_SET(winbindd_fd, &r_fds);
 447                 ZERO_STRUCT(tv);
 448                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 449                 tv.tv_sec = 5;
 450
 451                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 452                         winbind_close_sock();
 453                         return -1;                   /* Select error */
 454                 }
 455
 456                 if (selret == 0) {
 457                         /* Not ready for read yet... */
 458                         if (total_time >= 30) {
 459                                 /* Timeout */
 460                                 winbind_close_sock();
 461                                 return -1;
 462                         }
 463                         total_time += 5;
 464                         continue;
 465                 }
 466
 467                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 468
 469                         /* Do the Read */
 470
 471                         int result = read(winbindd_fd, (char *)buffer + nread,
 472                               count - nread);
 473
 474                         if ((result == -1) || (result == 0)) {
 475
 476                                 /* Read failed.  I think the only useful thing we
 477                                    can do here is just return -1 and fail since the
 478                                    transaction has failed half way through. */
 479
 480                                 winbind_close_sock();
 481                                 return -1;
 482                         }
 483
 484                         nread += result;
 485
 486                 }
 487         }
 488
 489         return nread;
 490 }
 491
 492 /* Read reply */
 493
 494 int winbindd_read_reply(struct winbindd_response *response)
 495 {
 496         int result1, result2 = 0;
 497
 498         if (!response) {
 499                 return -1;
 500         }
 501
 502         /* Read fixed length response */
 503
 504         result1 = winbind_read_sock(response,
 505                                     sizeof(struct winbindd_response));
 506         if (result1 == -1) {
 507                 return -1;
 508         }
 509
 510         /* We actually send the pointer value of the extra_data field from
 511            the server.  This has no meaning in the client's address space
 512            so we clear it out. */
 513
 514         response->extra_data.data = NULL;
 515
 516         /* Read variable length response */
 517
 518         if (response->length > sizeof(struct winbindd_response)) {
 519                 int extra_data_len = response->length -
 520                         sizeof(struct winbindd_response);
 521
 522                 /* Mallocate memory for extra data */
 523
 524                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 525                         return -1;
 526                 }
 527
 528                 result2 = winbind_read_sock(response->extra_data.data,
 529                                             extra_data_len);
 530                 if (result2 == -1) {
 531                         winbindd_free_response(response);
 532                         return -1;
 533                 }
 534         }
 535
 536         /* Return total amount of data read */
 537
 538         return result1 + result2;
 539 }
 540
 541 /*
 542  * send simple types of requests
 543  */
 544
 545 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 546                                  struct winbindd_request *request)
 547 {
 548         struct winbindd_request lrequest;
 549
 550         /* Check for our tricky environment variable */
 551
 552         if (winbind_env_set()) {
 553                 return NSS_STATUS_NOTFOUND;
 554         }
 555
 556         if (!request) {
 557                 ZERO_STRUCT(lrequest);
 558                 request = &lrequest;
 559         }
 560
 561         /* Fill in request and send down pipe */
 562
 563         winbindd_init_request(request, req_type);
 564
 565         if (winbind_write_sock(request, sizeof(*request),
 566                                request->wb_flags & WBFLAG_RECURSE,
 567                                need_priv) == -1) {
 568                 return NSS_STATUS_UNAVAIL;
 569         }
 570
 571         if ((request->extra_len != 0) &&
 572             (winbind_write_sock(request->extra_data.data,
 573                                 request->extra_len,
 574                                 request->wb_flags & WBFLAG_RECURSE,
 575                                 need_priv) == -1)) {
 576                 return NSS_STATUS_UNAVAIL;
 577         }
 578
 579         return NSS_STATUS_SUCCESS;
 580 }
 581
 582 /*
 583  * Get results from winbindd request
 584  */
 585
 586 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 587 {
 588         struct winbindd_response lresponse;
 589
 590         if (!response) {
 591                 ZERO_STRUCT(lresponse);
 592                 response = &lresponse;
 593         }
 594
 595         init_response(response);
 596
 597         /* Wait for reply */
 598         if (winbindd_read_reply(response) == -1) {
 599                 return NSS_STATUS_UNAVAIL;
 600         }
 601
 602         /* Throw away extra data if client didn't request it */
 603         if (response == &lresponse) {
 604                 winbindd_free_response(response);
 605         }
 606
 607         /* Copy reply data from socket */
 608         if (response->result != WINBINDD_OK) {
 609                 return NSS_STATUS_NOTFOUND;
 610         }
 611
 612         return NSS_STATUS_SUCCESS;
 613 }
 614
 615 /* Handle simple types of requests */
 616
 617 NSS_STATUS winbindd_request_response(int req_type,
 618                             struct winbindd_request *request,
 619                             struct winbindd_response *response)
 620 {
 621         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 622         int count = 0;
 623
 624         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 625                 status = winbindd_send_request(req_type, 0, request);
 626                 if (status != NSS_STATUS_SUCCESS)
 627                         return(status);
 628                 status = winbindd_get_response(response);
 629                 count += 1;
 630         }
 631
 632         return status;
 633 }
 634
 635 NSS_STATUS winbindd_priv_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, 1, 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 /*************************************************************************
 654  ************************************************************************/
 655
 656 const char *nss_err_str(NSS_STATUS ret)
 657 {
 658         switch (ret) {
 659                 case NSS_STATUS_TRYAGAIN:
 660                         return "NSS_STATUS_TRYAGAIN";
 661                 case NSS_STATUS_SUCCESS:
 662                         return "NSS_STATUS_SUCCESS";
 663                 case NSS_STATUS_NOTFOUND:
 664                         return "NSS_STATUS_NOTFOUND";
 665                 case NSS_STATUS_UNAVAIL:
 666                         return "NSS_STATUS_UNAVAIL";
 667 #ifdef NSS_STATUS_RETURN
 668                 case NSS_STATUS_RETURN:
 669                         return "NSS_STATUS_RETURN";
 670 #endif
 671                 default:
 672                         return "UNKNOWN RETURN CODE!!!!!!!";
 673         }
 674 }