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 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 Library 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 BOOL winbind_env_set( void );
  28 BOOL winbind_off( void );
  29 BOOL winbind_on( void );
  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 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 void init_request(struct winbindd_request *request, int request_type)
  49 {
  50         request->length = sizeof(struct winbindd_request);
  51
  52         request->cmd = (enum winbindd_cmd)request_type;
  53         request->pid = getpid();
  54
  55 }
  56
  57 /* Initialise a response structure */
  58
  59 static void init_response(struct winbindd_response *response)
  60 {
  61         /* Initialise return value */
  62
  63         response->result = WINBINDD_ERROR;
  64 }
  65
  66 /* Close established socket */
  67
  68 void close_sock(void)
  69 {
  70         if (winbindd_fd != -1) {
  71                 close(winbindd_fd);
  72                 winbindd_fd = -1;
  73         }
  74 }
  75
  76 #define CONNECT_TIMEOUT 30
  77
  78 /* Make sure socket handle isn't stdin, stdout or stderr */
  79 #define RECURSION_LIMIT 3
  80
  81 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  82 {
  83         int new_fd;
  84         if (fd >= 0 && fd <= 2) {
  85 #ifdef F_DUPFD
  86                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  87                         return -1;
  88                 }
  89                 /* Paranoia */
  90                 if (new_fd < 3) {
  91                         close(new_fd);
  92                         return -1;
  93                 }
  94                 close(fd);
  95                 return new_fd;
  96 #else
  97                 if (limit <= 0)
  98                         return -1;
  99
 100                 new_fd = dup(fd);
 101                 if (new_fd == -1)
 102                         return -1;
 103
 104                 /* use the program stack to hold our list of FDs to close */
 105                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 106                 close(fd);
 107                 return new_fd;
 108 #endif
 109         }
 110         return fd;
 111 }
 112
 113 /****************************************************************************
 114  Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 115  else
 116  if SYSV use O_NDELAY
 117  if BSD use FNDELAY
 118  Set close on exec also.
 119 ****************************************************************************/
 120
 121 static int make_safe_fd(int fd)
 122 {
 123         int result, flags;
 124         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 125         if (new_fd == -1) {
 126                 close(fd);
 127                 return -1;
 128         }
 129
 130         /* Socket should be nonblocking. */
 131 #ifdef O_NONBLOCK
 132 #define FLAG_TO_SET O_NONBLOCK
 133 #else
 134 #ifdef SYSV
 135 #define FLAG_TO_SET O_NDELAY
 136 #else /* BSD */
 137 #define FLAG_TO_SET FNDELAY
 138 #endif
 139 #endif
 140
 141         if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
 142                 close(new_fd);
 143                 return -1;
 144         }
 145
 146         flags |= FLAG_TO_SET;
 147         if (fcntl(new_fd, F_SETFL, flags) == -1) {
 148                 close(new_fd);
 149                 return -1;
 150         }
 151
 152 #undef FLAG_TO_SET
 153
 154         /* Socket should be closed on exec() */
 155 #ifdef FD_CLOEXEC
 156         result = flags = fcntl(new_fd, F_GETFD, 0);
 157         if (flags >= 0) {
 158                 flags |= FD_CLOEXEC;
 159                 result = fcntl( new_fd, F_SETFD, flags );
 160         }
 161         if (result < 0) {
 162                 close(new_fd);
 163                 return -1;
 164         }
 165 #endif
 166         return new_fd;
 167 }
 168
 169 /* Connect to winbindd socket */
 170
 171 static int winbind_named_pipe_sock(const char *dir)
 172 {
 173         struct sockaddr_un sunaddr;
 174         struct stat st;
 175         pstring path;
 176         int fd;
 177         int wait_time;
 178         int slept;
 179
 180         /* Check permissions on unix socket directory */
 181
 182         if (lstat(dir, &st) == -1) {
 183                 return -1;
 184         }
 185
 186         if (!S_ISDIR(st.st_mode) ||
 187             (st.st_uid != 0 && st.st_uid != geteuid())) {
 188                 return -1;
 189         }
 190
 191         /* Connect to socket */
 192
 193         strncpy(path, dir, sizeof(path) - 1);
 194         path[sizeof(path) - 1] = '\0';
 195
 196         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 197         path[sizeof(path) - 1] = '\0';
 198
 199         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 200         path[sizeof(path) - 1] = '\0';
 201
 202         ZERO_STRUCT(sunaddr);
 203         sunaddr.sun_family = AF_UNIX;
 204         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 205
 206         /* If socket file doesn't exist, don't bother trying to connect
 207            with retry.  This is an attempt to make the system usable when
 208            the winbindd daemon is not running. */
 209
 210         if (lstat(path, &st) == -1) {
 211                 return -1;
 212         }
 213
 214         /* Check permissions on unix socket file */
 215
 216         if (!S_ISSOCK(st.st_mode) ||
 217             (st.st_uid != 0 && st.st_uid != geteuid())) {
 218                 return -1;
 219         }
 220
 221         /* Connect to socket */
 222
 223         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 224                 return -1;
 225         }
 226
 227         /* Set socket non-blocking and close on exec. */
 228
 229         if ((fd = make_safe_fd( fd)) == -1) {
 230                 return fd;
 231         }
 232
 233         for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
 234                         wait_time += slept) {
 235                 struct timeval tv;
 236                 fd_set w_fds;
 237                 int ret;
 238                 int connect_errno = 0;
 239                 socklen_t errnosize;
 240
 241                 if (wait_time >= CONNECT_TIMEOUT)
 242                         goto error_out;
 243
 244                 switch (errno) {
 245                         case EINPROGRESS:
 246                                 FD_ZERO(&w_fds);
 247                                 FD_SET(fd, &w_fds);
 248                                 tv.tv_sec = CONNECT_TIMEOUT - wait_time;
 249                                 tv.tv_usec = 0;
 250
 251                                 ret = select(fd + 1, NULL, &w_fds, NULL, &tv);
 252
 253                                 if (ret > 0) {
 254                                         errnosize = sizeof(connect_errno);
 255
 256                                         ret = getsockopt(fd, SOL_SOCKET,
 257                                                         SO_ERROR, &connect_errno, &errnosize);
 258
 259                                         if (ret >= 0 && connect_errno == 0) {
 260                                                 /* Connect succeed */
 261                                                 goto out;
 262                                         }
 263                                 }
 264
 265                                 slept = CONNECT_TIMEOUT;
 266                                 break;
 267                         case EAGAIN:
 268                                 slept = rand() % 3 + 1;
 269                                 sleep(slept);
 270                                 break;
 271                         default:
 272                                 goto error_out;
 273                 }
 274
 275         }
 276
 277   out:
 278
 279         return fd;
 280
 281   error_out:
 282
 283         close(fd);
 284         return -1;
 285 }
 286
 287 /* Connect to winbindd socket */
 288
 289 static int winbind_open_pipe_sock(int recursing, int need_priv)
 290 {
 291 #ifdef HAVE_UNIXSOCKET
 292         static pid_t our_pid;
 293         struct winbindd_request request;
 294         struct winbindd_response response;
 295         ZERO_STRUCT(request);
 296         ZERO_STRUCT(response);
 297
 298         if (our_pid != getpid()) {
 299                 close_sock();
 300                 our_pid = getpid();
 301         }
 302
 303         if ((need_priv != 0) && (is_privileged == 0)) {
 304                 close_sock();
 305         }
 306
 307         if (winbindd_fd != -1) {
 308                 return winbindd_fd;
 309         }
 310
 311         if (recursing) {
 312                 return -1;
 313         }
 314
 315         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 316                 return -1;
 317         }
 318
 319         is_privileged = 0;
 320
 321         /* version-check the socket */
 322
 323         request.flags = WBFLAG_RECURSE;
 324         if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 325                 close_sock();
 326                 return -1;
 327         }
 328
 329         /* try and get priv pipe */
 330
 331         request.flags = WBFLAG_RECURSE;
 332         if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 333                 int fd;
 334                 if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
 335                         close(winbindd_fd);
 336                         winbindd_fd = fd;
 337                         is_privileged = 1;
 338                 }
 339         }
 340
 341         if ((need_priv != 0) && (is_privileged == 0)) {
 342                 return -1;
 343         }
 344
 345         SAFE_FREE(response.extra_data.data);
 346
 347         return winbindd_fd;
 348 #else
 349         return -1;
 350 #endif /* HAVE_UNIXSOCKET */
 351 }
 352
 353 /* Write data to winbindd socket */
 354
 355 int write_sock(void *buffer, int count, int recursing, int need_priv)
 356 {
 357         int result, nwritten;
 358
 359         /* Open connection to winbind daemon */
 360
 361  restart:
 362
 363         if (winbind_open_pipe_sock(recursing, need_priv) == -1) {
 364                 return -1;
 365         }
 366
 367         /* Write data to socket */
 368
 369         nwritten = 0;
 370
 371         while(nwritten < count) {
 372                 struct timeval tv;
 373                 fd_set r_fds;
 374
 375                 /* Catch pipe close on other end by checking if a read()
 376                    call would not block by calling select(). */
 377
 378                 FD_ZERO(&r_fds);
 379                 FD_SET(winbindd_fd, &r_fds);
 380                 ZERO_STRUCT(tv);
 381
 382                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 383                         close_sock();
 384                         return -1;                   /* Select error */
 385                 }
 386
 387                 /* Write should be OK if fd not available for reading */
 388
 389                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 390
 391                         /* Do the write */
 392
 393                         result = write(winbindd_fd,
 394                                        (char *)buffer + nwritten,
 395                                        count - nwritten);
 396
 397                         if ((result == -1) || (result == 0)) {
 398
 399                                 /* Write failed */
 400
 401                                 close_sock();
 402                                 return -1;
 403                         }
 404
 405                         nwritten += result;
 406
 407                 } else {
 408
 409                         /* Pipe has closed on remote end */
 410
 411                         close_sock();
 412                         goto restart;
 413                 }
 414         }
 415
 416         return nwritten;
 417 }
 418
 419 /* Read data from winbindd socket */
 420
 421 static int read_sock(void *buffer, int count)
 422 {
 423         int result = 0, nread = 0;
 424         int total_time = 0, selret;
 425
 426         if (winbindd_fd == -1) {
 427                 return -1;
 428         }
 429
 430         /* Read data from socket */
 431         while(nread < count) {
 432                 struct timeval tv;
 433                 fd_set r_fds;
 434
 435                 /* Catch pipe close on other end by checking if a read()
 436                    call would not block by calling select(). */
 437
 438                 FD_ZERO(&r_fds);
 439                 FD_SET(winbindd_fd, &r_fds);
 440                 ZERO_STRUCT(tv);
 441                 /* Wait for 5 seconds for a reply. May need to parameterise this... */
 442                 tv.tv_sec = 5;
 443
 444                 if ((selret = select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv)) == -1) {
 445                         close_sock();
 446                         return -1;                   /* Select error */
 447                 }
 448
 449                 if (selret == 0) {
 450                         /* Not ready for read yet... */
 451                         if (total_time >= 30) {
 452                                 /* Timeout */
 453                                 close_sock();
 454                                 return -1;
 455                         }
 456                         total_time += 5;
 457                         continue;
 458                 }
 459
 460                 if (FD_ISSET(winbindd_fd, &r_fds)) {
 461
 462                         /* Do the Read */
 463
 464                         result = read(winbindd_fd, (char *)buffer + nread,
 465                               count - nread);
 466
 467                         if ((result == -1) || (result == 0)) {
 468
 469                                 /* Read failed.  I think the only useful thing we
 470                                    can do here is just return -1 and fail since the
 471                                    transaction has failed half way through. */
 472
 473                                 close_sock();
 474                                 return -1;
 475                         }
 476
 477                         nread += result;
 478
 479                 }
 480         }
 481
 482         return result;
 483 }
 484
 485 /* Read reply */
 486
 487 int read_reply(struct winbindd_response *response)
 488 {
 489         int result1, result2 = 0;
 490
 491         if (!response) {
 492                 return -1;
 493         }
 494
 495         /* Read fixed length response */
 496
 497         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 498             == -1) {
 499
 500                 return -1;
 501         }
 502
 503         /* We actually send the pointer value of the extra_data field from
 504            the server.  This has no meaning in the client's address space
 505            so we clear it out. */
 506
 507         response->extra_data.data = NULL;
 508
 509         /* Read variable length response */
 510
 511         if (response->length > sizeof(struct winbindd_response)) {
 512                 int extra_data_len = response->length -
 513                         sizeof(struct winbindd_response);
 514
 515                 /* Mallocate memory for extra data */
 516
 517                 if (!(response->extra_data.data = malloc(extra_data_len))) {
 518                         return -1;
 519                 }
 520
 521                 if ((result2 = read_sock(response->extra_data.data, extra_data_len))
 522                     == -1) {
 523                         free_response(response);
 524                         return -1;
 525                 }
 526         }
 527
 528         /* Return total amount of data read */
 529
 530         return result1 + result2;
 531 }
 532
 533 BOOL winbind_env_set( void )
 534 {
 535         char *env;
 536
 537         if ((env=getenv(WINBINDD_DONT_ENV)) != NULL) {
 538                 if(strcmp(env, "1") == 0) {
 539                         return True;
 540                 }
 541         }
 542         return False;
 543 }
 544
 545 /*
 546  * send simple types of requests
 547  */
 548
 549 NSS_STATUS winbindd_send_request(int req_type, int need_priv,
 550                                  struct winbindd_request *request)
 551 {
 552         struct winbindd_request lrequest;
 553
 554         /* Check for our tricky environment variable */
 555
 556         if (winbind_env_set()) {
 557                 return NSS_STATUS_NOTFOUND;
 558         }
 559
 560         if (!request) {
 561                 ZERO_STRUCT(lrequest);
 562                 request = &lrequest;
 563         }
 564
 565         /* Fill in request and send down pipe */
 566
 567         init_request(request, req_type);
 568
 569         if (write_sock(request, sizeof(*request),
 570                        request->flags & WBFLAG_RECURSE, need_priv) == -1) {
 571                 return NSS_STATUS_UNAVAIL;
 572         }
 573
 574         if ((request->extra_len != 0) &&
 575             (write_sock(request->extra_data.data, request->extra_len,
 576                         request->flags & WBFLAG_RECURSE, need_priv) == -1)) {
 577                 return NSS_STATUS_UNAVAIL;
 578         }
 579
 580         return NSS_STATUS_SUCCESS;
 581 }
 582
 583 /*
 584  * Get results from winbindd request
 585  */
 586
 587 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 588 {
 589         struct winbindd_response lresponse;
 590
 591         if (!response) {
 592                 ZERO_STRUCT(lresponse);
 593                 response = &lresponse;
 594         }
 595
 596         init_response(response);
 597
 598         /* Wait for reply */
 599         if (read_reply(response) == -1) {
 600                 return NSS_STATUS_UNAVAIL;
 601         }
 602
 603         /* Throw away extra data if client didn't request it */
 604         if (response == &lresponse) {
 605                 free_response(response);
 606         }
 607
 608         /* Copy reply data from socket */
 609         if (response->result != WINBINDD_OK) {
 610                 return NSS_STATUS_NOTFOUND;
 611         }
 612
 613         return NSS_STATUS_SUCCESS;
 614 }
 615
 616 /* Handle simple types of requests */
 617
 618 NSS_STATUS winbindd_request_response(int req_type,
 619                             struct winbindd_request *request,
 620                             struct winbindd_response *response)
 621 {
 622         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 623         int count = 0;
 624
 625         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 626                 status = winbindd_send_request(req_type, 0, request);
 627                 if (status != NSS_STATUS_SUCCESS)
 628                         return(status);
 629                 status = winbindd_get_response(response);
 630                 count += 1;
 631         }
 632
 633         return status;
 634 }
 635
 636 NSS_STATUS winbindd_priv_request_response(int req_type,
 637                                           struct winbindd_request *request,
 638                                           struct winbindd_response *response)
 639 {
 640         NSS_STATUS status = NSS_STATUS_UNAVAIL;
 641         int count = 0;
 642
 643         while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
 644                 status = winbindd_send_request(req_type, 1, request);
 645                 if (status != NSS_STATUS_SUCCESS)
 646                         return(status);
 647                 status = winbindd_get_response(response);
 648                 count += 1;
 649         }
 650
 651         return status;
 652 }
 653
 654 /*************************************************************************
 655  A couple of simple functions to disable winbindd lookups and re-
 656  enable them
 657  ************************************************************************/
 658
 659 /* Use putenv() instead of setenv() in these functions as not all
 660    environments have the latter. */
 661
 662 BOOL winbind_off( void )
 663 {
 664         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=1");
 665
 666         return putenv(s) != -1;
 667 }
 668
 669 BOOL winbind_on( void )
 670 {
 671         static char *s = CONST_DISCARD(char *, WINBINDD_DONT_ENV "=0");
 672
 673         return putenv(s) != -1;
 674 }
 675