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                 /* Parinoia */
  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                 DEBUG(10, ("error connecting to pipe socket: %s\n",
 195                         strerror(errno)));
 196                 close(fd);
 197                 return -1;
 198         }
 199
 200         return fd;
 201 }
 202
 203 /* Connect to winbindd socket */
 204
 205 int winbind_open_pipe_sock(void)
 206 {
 207 #ifdef HAVE_UNIXSOCKET
 208         static pid_t our_pid;
 209         struct winbindd_request request;
 210         struct winbindd_response response;
 211         ZERO_STRUCT(request);
 212         ZERO_STRUCT(response);
 213
 214         if (our_pid != getpid()) {
 215                 close_sock();
 216                 our_pid = getpid();
 217         }
 218
 219         if (winbindd_fd != -1) {
 220                 return winbindd_fd;
 221         }
 222
 223         if ((winbindd_fd = winbind_named_pipe_sock(WINBINDD_SOCKET_DIR)) == -1) {
 224                 return -1;
 225         }
 226
 227         /* version-check the socket */
 228
 229         if ((winbindd_request(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
 230                 close_sock();
 231                 return -1;
 232         }
 233
 234         /* try and get priv pipe */
 235
 236         if (winbindd_request(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
 237                 int fd;
 238                 if ((fd = winbind_named_pipe_sock(response.extra_data)) != -1) {
 239                         close(winbindd_fd);
 240                         winbindd_fd = fd;
 241                 }
 242         }
 243
 244         SAFE_FREE(response.extra_data);
 245
 246         return winbindd_fd;
 247 #else
 248         return -1;
 249 #endif /* HAVE_UNIXSOCKET */
 250 }
 251
 252 /* Write data to winbindd socket */
 253
 254 int write_sock(void *buffer, int count)
 255 {
 256         int result, nwritten;
 257
 258         /* Open connection to winbind daemon */
 259
 260  restart:
 261
 262         if (winbind_open_pipe_sock() == -1) {
 263                 return -1;
 264         }
 265
 266         /* Write data to socket */
 267
 268         nwritten = 0;
 269
 270         while(nwritten < count) {
 271                 struct timeval tv;
 272                 fd_set r_fds;
 273
 274                 /* Catch pipe close on other end by checking if a read()
 275                    call would not block by calling select(). */
 276
 277                 FD_ZERO(&r_fds);
 278                 FD_SET(winbindd_fd, &r_fds);
 279                 ZERO_STRUCT(tv);
 280
 281                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 282                         close_sock();
 283                         return -1;                   /* Select error */
 284                 }
 285
 286                 /* Write should be OK if fd not available for reading */
 287
 288                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 289
 290                         /* Do the write */
 291
 292                         result = write(winbindd_fd,
 293                                        (char *)buffer + nwritten,
 294                                        count - nwritten);
 295
 296                         if ((result == -1) || (result == 0)) {
 297
 298                                 /* Write failed */
 299
 300                                 close_sock();
 301                                 return -1;
 302                         }
 303
 304                         nwritten += result;
 305
 306                 } else {
 307
 308                         /* Pipe has closed on remote end */
 309
 310                         close_sock();
 311                         goto restart;
 312                 }
 313         }
 314
 315         return nwritten;
 316 }
 317
 318 /* Read data from winbindd socket */
 319
 320 static int read_sock(void *buffer, int count)
 321 {
 322         int result = 0, nread = 0;
 323
 324         /* Read data from socket */
 325
 326         while(nread < count) {
 327
 328                 result = read(winbindd_fd, (char *)buffer + nread,
 329                               count - nread);
 330
 331                 if ((result == -1) || (result == 0)) {
 332
 333                         /* Read failed.  I think the only useful thing we
 334                            can do here is just return -1 and fail since the
 335                            transaction has failed half way through. */
 336
 337                         close_sock();
 338                         return -1;
 339                 }
 340
 341                 nread += result;
 342         }
 343
 344         return result;
 345 }
 346
 347 /* Read reply */
 348
 349 int read_reply(struct winbindd_response *response)
 350 {
 351         int result1, result2 = 0;
 352
 353         if (!response) {
 354                 return -1;
 355         }
 356
 357         /* Read fixed length response */
 358
 359         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 360             == -1) {
 361
 362                 return -1;
 363         }
 364
 365         /* We actually send the pointer value of the extra_data field from
 366            the server.  This has no meaning in the client's address space
 367            so we clear it out. */
 368
 369         response->extra_data = NULL;
 370
 371         /* Read variable length response */
 372
 373         if (response->length > sizeof(struct winbindd_response)) {
 374                 int extra_data_len = response->length -
 375                         sizeof(struct winbindd_response);
 376
 377                 /* Mallocate memory for extra data */
 378
 379                 if (!(response->extra_data = malloc(extra_data_len))) {
 380                         return -1;
 381                 }
 382
 383                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 384                     == -1) {
 385                         free_response(response);
 386                         return -1;
 387                 }
 388         }
 389
 390         /* Return total amount of data read */
 391
 392         return result1 + result2;
 393 }
 394
 395 /*
 396  * send simple types of requests
 397  */
 398
 399 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 400 {
 401         struct winbindd_request lrequest;
 402         char *env;
 403         int  value;
 404
 405         /* Check for our tricky environment variable */
 406
 407         if ( (env = getenv(WINBINDD_DONT_ENV)) != NULL ) {
 408                 value = atoi(env);
 409                 if ( value == 1 )
 410                         return NSS_STATUS_NOTFOUND;
 411         }
 412
 413         if (!request) {
 414                 ZERO_STRUCT(lrequest);
 415                 request = &lrequest;
 416         }
 417
 418         /* Fill in request and send down pipe */
 419
 420         init_request(request, req_type);
 421
 422         if (write_sock(request, sizeof(*request)) == -1) {
 423                 return NSS_STATUS_UNAVAIL;
 424         }
 425
 426         return NSS_STATUS_SUCCESS;
 427 }
 428
 429 /*
 430  * Get results from winbindd request
 431  */
 432
 433 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 434 {
 435         struct winbindd_response lresponse;
 436
 437         if (!response) {
 438                 ZERO_STRUCT(lresponse);
 439                 response = &lresponse;
 440         }
 441
 442         init_response(response);
 443
 444         /* Wait for reply */
 445         if (read_reply(response) == -1) {
 446                 return NSS_STATUS_UNAVAIL;
 447         }
 448
 449         /* Throw away extra data if client didn't request it */
 450         if (response == &lresponse) {
 451                 free_response(response);
 452         }
 453
 454         /* Copy reply data from socket */
 455         if (response->result != WINBINDD_OK) {
 456                 return NSS_STATUS_NOTFOUND;
 457         }
 458
 459         return NSS_STATUS_SUCCESS;
 460 }
 461
 462 /* Handle simple types of requests */
 463
 464 NSS_STATUS winbindd_request(int req_type,
 465                             struct winbindd_request *request,
 466                             struct winbindd_response *response)
 467 {
 468         NSS_STATUS status;
 469
 470         status = winbindd_send_request(req_type, request);
 471         if (status != NSS_STATUS_SUCCESS)
 472                 return(status);
 473         return winbindd_get_response(response);
 474 }
 475
 476 /*************************************************************************
 477  A couple of simple jfunctions to disable winbindd lookups and re-
 478  enable them
 479  ************************************************************************/
 480
 481 BOOL winbind_off( void )
 482 {
 483         return (setenv( WINBINDD_DONT_ENV, "1", 1 ) != -1);
 484 }
 485
 486 BOOL winbind_on( void )
 487 {
 488         return (setenv( WINBINDD_DONT_ENV, "0", 1 ) != -1);
 489 }
 490