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 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                 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         return winbindd_fd;
 243 #else
 244         return -1;
 245 #endif /* HAVE_UNIXSOCKET */
 246 }
 247
 248 /* Write data to winbindd socket */
 249
 250 int write_sock(void *buffer, int count)
 251 {
 252         int result, nwritten;
 253
 254         /* Open connection to winbind daemon */
 255
 256  restart:
 257
 258         if (winbind_open_pipe_sock() == -1) {
 259                 return -1;
 260         }
 261
 262         /* Write data to socket */
 263
 264         nwritten = 0;
 265
 266         while(nwritten < count) {
 267                 struct timeval tv;
 268                 fd_set r_fds;
 269
 270                 /* Catch pipe close on other end by checking if a read()
 271                    call would not block by calling select(). */
 272
 273                 FD_ZERO(&r_fds);
 274                 FD_SET(winbindd_fd, &r_fds);
 275                 ZERO_STRUCT(tv);
 276
 277                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 278                         close_sock();
 279                         return -1;                   /* Select error */
 280                 }
 281
 282                 /* Write should be OK if fd not available for reading */
 283
 284                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 285
 286                         /* Do the write */
 287
 288                         result = write(winbindd_fd,
 289                                        (char *)buffer + nwritten,
 290                                        count - nwritten);
 291
 292                         if ((result == -1) || (result == 0)) {
 293
 294                                 /* Write failed */
 295
 296                                 close_sock();
 297                                 return -1;
 298                         }
 299
 300                         nwritten += result;
 301
 302                 } else {
 303
 304                         /* Pipe has closed on remote end */
 305
 306                         close_sock();
 307                         goto restart;
 308                 }
 309         }
 310
 311         return nwritten;
 312 }
 313
 314 /* Read data from winbindd socket */
 315
 316 static int read_sock(void *buffer, int count)
 317 {
 318         int result = 0, nread = 0;
 319
 320         /* Read data from socket */
 321
 322         while(nread < count) {
 323
 324                 result = read(winbindd_fd, (char *)buffer + nread,
 325                               count - nread);
 326
 327                 if ((result == -1) || (result == 0)) {
 328
 329                         /* Read failed.  I think the only useful thing we
 330                            can do here is just return -1 and fail since the
 331                            transaction has failed half way through. */
 332
 333                         close_sock();
 334                         return -1;
 335                 }
 336
 337                 nread += result;
 338         }
 339
 340         return result;
 341 }
 342
 343 /* Read reply */
 344
 345 int read_reply(struct winbindd_response *response)
 346 {
 347         int result1, result2 = 0;
 348
 349         if (!response) {
 350                 return -1;
 351         }
 352
 353         /* Read fixed length response */
 354
 355         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 356             == -1) {
 357
 358                 return -1;
 359         }
 360
 361         /* We actually send the pointer value of the extra_data field from
 362            the server.  This has no meaning in the client's address space
 363            so we clear it out. */
 364
 365         response->extra_data = NULL;
 366
 367         /* Read variable length response */
 368
 369         if (response->length > sizeof(struct winbindd_response)) {
 370                 int extra_data_len = response->length -
 371                         sizeof(struct winbindd_response);
 372
 373                 /* Mallocate memory for extra data */
 374
 375                 if (!(response->extra_data = malloc(extra_data_len))) {
 376                         return -1;
 377                 }
 378
 379                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 380                     == -1) {
 381                         free_response(response);
 382                         return -1;
 383                 }
 384         }
 385
 386         /* Return total amount of data read */
 387
 388         return result1 + result2;
 389 }
 390
 391 /*
 392  * send simple types of requests
 393  */
 394
 395 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 396 {
 397         struct winbindd_request lrequest;
 398
 399         /* Check for our tricky environment variable */
 400
 401         if (getenv(WINBINDD_DONT_ENV)) {
 402                 return NSS_STATUS_NOTFOUND;
 403         }
 404
 405         if (!request) {
 406                 ZERO_STRUCT(lrequest);
 407                 request = &lrequest;
 408         }
 409
 410         /* Fill in request and send down pipe */
 411
 412         init_request(request, req_type);
 413
 414         if (write_sock(request, sizeof(*request)) == -1) {
 415                 return NSS_STATUS_UNAVAIL;
 416         }
 417
 418         return NSS_STATUS_SUCCESS;
 419 }
 420
 421 /*
 422  * Get results from winbindd request
 423  */
 424
 425 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 426 {
 427         struct winbindd_response lresponse;
 428
 429         if (!response) {
 430                 ZERO_STRUCT(lresponse);
 431                 response = &lresponse;
 432         }
 433
 434         init_response(response);
 435
 436         /* Wait for reply */
 437         if (read_reply(response) == -1) {
 438                 return NSS_STATUS_UNAVAIL;
 439         }
 440
 441         /* Throw away extra data if client didn't request it */
 442         if (response == &lresponse) {
 443                 free_response(response);
 444         }
 445
 446         /* Copy reply data from socket */
 447         if (response->result != WINBINDD_OK) {
 448                 return NSS_STATUS_NOTFOUND;
 449         }
 450
 451         return NSS_STATUS_SUCCESS;
 452 }
 453
 454 /* Handle simple types of requests */
 455
 456 NSS_STATUS winbindd_request(int req_type,
 457                             struct winbindd_request *request,
 458                             struct winbindd_response *response)
 459 {
 460         NSS_STATUS status;
 461
 462         status = winbindd_send_request(req_type, request);
 463         if (status != NSS_STATUS_SUCCESS)
 464                 return(status);
 465         return winbindd_get_response(response);
 466 }