source3/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 /* Make sure socket handle isn't stdin, stdout or stderr */
  74 #define RECURSION_LIMIT 3
  75
  76 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  77 {
  78         int new_fd;
  79         if (fd >= 0 && fd <= 2) {
  80 #ifdef F_DUPFD
  81                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  82                         return -1;
  83                 }
  84                 /* Paranoia */
  85                 if (new_fd < 3) {
  86                         close(new_fd);
  87                         return -1;
  88                 }
  89                 close(fd);
  90                 return new_fd;
  91 #else
  92                 if (limit <= 0)
  93                         return -1;
  94
  95                 new_fd = dup(fd);
  96                 if (new_fd == -1)
  97                         return -1;
  98
  99                 /* use the program stack to hold our list of FDs to close */
 100                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 101                 close(fd);
 102                 return new_fd;
 103 #endif
 104         }
 105         return fd;
 106 }
 107
 108 static int make_safe_fd(int fd)
 109 {
 110         int result, flags;
 111         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 112         if (new_fd == -1) {
 113                 close(fd);
 114                 return -1;
 115         }
 116         /* Socket should be closed on exec() */
 117
 118 #ifdef FD_CLOEXEC
 119         result = flags = fcntl(new_fd, F_GETFD, 0);
 120         if (flags >= 0) {
 121                 flags |= FD_CLOEXEC;
 122                 result = fcntl( new_fd, F_SETFD, flags );
 123         }
 124         if (result < 0) {
 125                 close(new_fd);
 126                 return -1;
 127         }
 128 #endif
 129         return new_fd;
 130 }
 131
 132 /* Connect to winbindd socket */
 133
 134 static int winbind_named_pipe_sock(const char *dir)
 135 {
 136         struct sockaddr_un sunaddr;
 137         struct stat st;
 138         pstring path;
 139         int fd;
 140
 141         /* Check permissions on unix socket directory */
 142
 143         if (lstat(dir, &st) == -1) {
 144                 return -1;
 145         }
 146
 147         if (!S_ISDIR(st.st_mode) ||
 148             (st.st_uid != 0 && st.st_uid != geteuid())) {
 149                 return -1;
 150         }
 151
 152         /* Connect to socket */
 153
 154         strncpy(path, dir, sizeof(path) - 1);
 155         path[sizeof(path) - 1] = '\0';
 156
 157         strncat(path, "/", sizeof(path) - 1 - strlen(path));
 158         path[sizeof(path) - 1] = '\0';
 159
 160         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1 - strlen(path));
 161         path[sizeof(path) - 1] = '\0';
 162
 163         ZERO_STRUCT(sunaddr);
 164         sunaddr.sun_family = AF_UNIX;
 165         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 166
 167         /* If socket file doesn't exist, don't bother trying to connect
 168            with retry.  This is an attempt to make the system usable when
 169            the winbindd daemon is not running. */
 170
 171         if (lstat(path, &st) == -1) {
 172                 return -1;
 173         }
 174
 175         /* Check permissions on unix socket file */
 176
 177         if (!S_ISSOCK(st.st_mode) ||
 178             (st.st_uid != 0 && st.st_uid != geteuid())) {
 179                 return -1;
 180         }
 181
 182         /* Connect to socket */
 183
 184         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 185                 return -1;
 186         }
 187
 188         if ((fd = make_safe_fd( fd)) == -1) {
 189                 return fd;
 190         }
 191
 192         if (connect(fd, (struct sockaddr *)&sunaddr,
 193                     sizeof(sunaddr)) == -1) {
 194                 close(fd);
 195                 return -1;
 196         }
 197
 198         return fd;
 199 }
 200
 201 /* Connect to winbindd socket */
 202
 203 int winbind_open_pipe_sock(void)
 204 {
 205 #ifdef HAVE_UNIXSOCKET
 206         static pid_t our_pid;
 207         struct winbindd_request request;
 208         struct winbindd_response response;
 209         ZERO_STRUCT(request);
 210         ZERO_STRUCT(response);
 211
 212         if (our_pid != getpid()) {
 213                 close_sock();
 214                 our_pid = getpid();
 215         }
 216
 217         if (winbindd_fd != -1) {
 218                 return winbindd_fd;
 219         }
 220
 221         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 222                 return -1;
 223         }
 224
 225         /* version-check the socket */
 226
 227         if ((winbindd_request(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 228                 close_sock();
 229                 return -1;
 230         }
 231
 232         /* try and get priv pipe */
 233
 234         if (winbindd_request(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 235                 int fd;
 236                 if ((fd = winbind_named_pipe_sock(response.extra_data)) != -1) {
 237                         close(winbindd_fd);
 238                         winbindd_fd = fd;
 239                 }
 240         }
 241
 242         SAFE_FREE(response.extra_data);
 243
 244         return winbindd_fd;
 245 #else
 246         return -1;
 247 #endif /* HAVE_UNIXSOCKET */
 248 }
 249
 250 /* Write data to winbindd socket */
 251
 252 int write_sock(void *buffer, int count)
 253 {
 254         int result, nwritten;
 255
 256         /* Open connection to winbind daemon */
 257
 258  restart:
 259
 260         if (winbind_open_pipe_sock() == -1) {
 261                 return -1;
 262         }
 263
 264         /* Write data to socket */
 265
 266         nwritten = 0;
 267
 268         while(nwritten < count) {
 269                 struct timeval tv;
 270                 fd_set r_fds;
 271
 272                 /* Catch pipe close on other end by checking if a read()
 273                    call would not block by calling select(). */
 274
 275                 FD_ZERO(&r_fds);
 276                 FD_SET(winbindd_fd, &r_fds);
 277                 ZERO_STRUCT(tv);
 278
 279                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 280                         close_sock();
 281                         return -1;                   /* Select error */
 282                 }
 283
 284                 /* Write should be OK if fd not available for reading */
 285
 286                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 287
 288                         /* Do the write */
 289
 290                         result = write(winbindd_fd,
 291                                        (char *)buffer + nwritten,
 292                                        count - nwritten);
 293
 294                         if ((result == -1) || (result == 0)) {
 295
 296                                 /* Write failed */
 297
 298                                 close_sock();
 299                                 return -1;
 300                         }
 301
 302                         nwritten += result;
 303
 304                 } else {
 305
 306                         /* Pipe has closed on remote end */
 307
 308                         close_sock();
 309                         goto restart;
 310                 }
 311         }
 312
 313         return nwritten;
 314 }
 315
 316 /* Read data from winbindd socket */
 317
 318 static int read_sock(void *buffer, int count)
 319 {
 320         int result = 0, nread = 0;
 321
 322         /* Read data from socket */
 323
 324         while(nread < count) {
 325
 326                 result = read(winbindd_fd, (char *)buffer + nread,
 327                               count - nread);
 328
 329                 if ((result == -1) || (result == 0)) {
 330
 331                         /* Read failed.  I think the only useful thing we
 332                            can do here is just return -1 and fail since the
 333                            transaction has failed half way through. */
 334
 335                         close_sock();
 336                         return -1;
 337                 }
 338
 339                 nread += result;
 340         }
 341
 342         return result;
 343 }
 344
 345 /* Read reply */
 346
 347 int read_reply(struct winbindd_response *response)
 348 {
 349         int result1, result2 = 0;
 350
 351         if (!response) {
 352                 return -1;
 353         }
 354
 355         /* Read fixed length response */
 356
 357         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 358             == -1) {
 359
 360                 return -1;
 361         }
 362
 363         /* We actually send the pointer value of the extra_data field from
 364            the server.  This has no meaning in the client's address space
 365            so we clear it out. */
 366
 367         response->extra_data = NULL;
 368
 369         /* Read variable length response */
 370
 371         if (response->length > sizeof(struct winbindd_response)) {
 372                 int extra_data_len = response->length -
 373                         sizeof(struct winbindd_response);
 374
 375                 /* Mallocate memory for extra data */
 376
 377                 if (!(response->extra_data = malloc(extra_data_len))) {
 378                         return -1;
 379                 }
 380
 381                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 382                     == -1) {
 383                         free_response(response);
 384                         return -1;
 385                 }
 386         }
 387
 388         /* Return total amount of data read */
 389
 390         return result1 + result2;
 391 }
 392
 393 /*
 394  * send simple types of requests
 395  */
 396
 397 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 398 {
 399         struct winbindd_request lrequest;
 400         char *env;
 401         int  value;
 402
 403         /* Check for our tricky environment variable */
 404
 405         if ( (env = getenv(WINBINDD_DONT_ENV)) != NULL ) {
 406                 value = atoi(env);
 407                 if ( value == 1 )
 408                         return NSS_STATUS_NOTFOUND;
 409         }
 410
 411         if (!request) {
 412                 ZERO_STRUCT(lrequest);
 413                 request = &lrequest;
 414         }
 415
 416         /* Fill in request and send down pipe */
 417
 418         init_request(request, req_type);
 419
 420         if (write_sock(request, sizeof(*request)) == -1) {
 421                 return NSS_STATUS_UNAVAIL;
 422         }
 423
 424         return NSS_STATUS_SUCCESS;
 425 }
 426
 427 /*
 428  * Get results from winbindd request
 429  */
 430
 431 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 432 {
 433         struct winbindd_response lresponse;
 434
 435         if (!response) {
 436                 ZERO_STRUCT(lresponse);
 437                 response = &lresponse;
 438         }
 439
 440         init_response(response);
 441
 442         /* Wait for reply */
 443         if (read_reply(response) == -1) {
 444                 return NSS_STATUS_UNAVAIL;
 445         }
 446
 447         /* Throw away extra data if client didn't request it */
 448         if (response == &lresponse) {
 449                 free_response(response);
 450         }
 451
 452         /* Copy reply data from socket */
 453         if (response->result != WINBINDD_OK) {
 454                 return NSS_STATUS_NOTFOUND;
 455         }
 456
 457         return NSS_STATUS_SUCCESS;
 458 }
 459
 460 /* Handle simple types of requests */
 461
 462 NSS_STATUS winbindd_request(int req_type,
 463                             struct winbindd_request *request,
 464                             struct winbindd_response *response)
 465 {
 466         NSS_STATUS status;
 467
 468         status = winbindd_send_request(req_type, request);
 469         if (status != NSS_STATUS_SUCCESS)
 470                 return(status);
 471         return winbindd_get_response(response);
 472 }
 473
 474 /*************************************************************************
 475  A couple of simple functions to disable winbindd lookups and re-
 476  enable them
 477  ************************************************************************/
 478
 479 /* Use putenv() instead of setenv() in these functions as not all
 480    environments have the latter. */
 481
 482 BOOL winbind_off( void )
 483 {
 484         static char *s = WINBINDD_DONT_ENV "=1";
 485
 486         return putenv(s) != -1;
 487 }
 488
 489 BOOL winbind_on( void )
 490 {
 491         static char *s = WINBINDD_DONT_ENV "=0";
 492
 493         return putenv(s) != -1;
 494 }