source4/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 int winbind_open_pipe_sock(void)
 135 {
 136 #ifdef HAVE_UNIXSOCKET
 137         struct sockaddr_un sunaddr;
 138         static pid_t our_pid;
 139         struct stat st;
 140         pstring path;
 141         int fd;
 142
 143         if (our_pid != getpid()) {
 144                 close_sock();
 145                 our_pid = getpid();
 146         }
 147
 148         if (winbindd_fd != -1) {
 149                 return winbindd_fd;
 150         }
 151
 152         /* Check permissions on unix socket directory */
 153
 154         if (lstat(WINBINDD_SOCKET_DIR, &st) == -1) {
 155                 return -1;
 156         }
 157
 158         if (!S_ISDIR(st.st_mode) ||
 159             (st.st_uid != 0 && st.st_uid != geteuid())) {
 160                 return -1;
 161         }
 162
 163         /* Connect to socket */
 164
 165         strncpy(path, WINBINDD_SOCKET_DIR, sizeof(path) - 1);
 166         path[sizeof(path) - 1] = '\0';
 167
 168         strncat(path, "/", sizeof(path) - 1);
 169         path[sizeof(path) - 1] = '\0';
 170
 171         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1);
 172         path[sizeof(path) - 1] = '\0';
 173
 174         ZERO_STRUCT(sunaddr);
 175         sunaddr.sun_family = AF_UNIX;
 176         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 177
 178         /* If socket file doesn't exist, don't bother trying to connect
 179            with retry.  This is an attempt to make the system usable when
 180            the winbindd daemon is not running. */
 181
 182         if (lstat(path, &st) == -1) {
 183                 return -1;
 184         }
 185
 186         /* Check permissions on unix socket file */
 187
 188         if (!S_ISSOCK(st.st_mode) ||
 189             (st.st_uid != 0 && st.st_uid != geteuid())) {
 190                 return -1;
 191         }
 192
 193         /* Connect to socket */
 194
 195         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 196                 return -1;
 197         }
 198
 199         if ((winbindd_fd = make_safe_fd( fd)) == -1) {
 200                 return winbindd_fd;
 201         }
 202
 203         if (connect(winbindd_fd, (struct sockaddr *)&sunaddr,
 204                     sizeof(sunaddr)) == -1) {
 205                 close_sock();
 206                 return -1;
 207         }
 208
 209         return winbindd_fd;
 210 #else
 211         return -1;
 212 #endif /* HAVE_UNIXSOCKET */
 213 }
 214
 215 /* Write data to winbindd socket */
 216
 217 int write_sock(void *buffer, int count)
 218 {
 219         int result, nwritten;
 220
 221         /* Open connection to winbind daemon */
 222
 223  restart:
 224
 225         if (winbind_open_pipe_sock() == -1) {
 226                 return -1;
 227         }
 228
 229         /* Write data to socket */
 230
 231         nwritten = 0;
 232
 233         while(nwritten < count) {
 234                 struct timeval tv;
 235                 fd_set r_fds;
 236
 237                 /* Catch pipe close on other end by checking if a read()
 238                    call would not block by calling select(). */
 239
 240                 FD_ZERO(&r_fds);
 241                 FD_SET(winbindd_fd, &r_fds);
 242                 ZERO_STRUCT(tv);
 243
 244                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 245                         close_sock();
 246                         return -1;                   /* Select error */
 247                 }
 248
 249                 /* Write should be OK if fd not available for reading */
 250
 251                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 252
 253                         /* Do the write */
 254
 255                         result = write(winbindd_fd,
 256                                        (char *)buffer + nwritten,
 257                                        count - nwritten);
 258
 259                         if ((result == -1) || (result == 0)) {
 260
 261                                 /* Write failed */
 262
 263                                 close_sock();
 264                                 return -1;
 265                         }
 266
 267                         nwritten += result;
 268
 269                 } else {
 270
 271                         /* Pipe has closed on remote end */
 272
 273                         close_sock();
 274                         goto restart;
 275                 }
 276         }
 277
 278         return nwritten;
 279 }
 280
 281 /* Read data from winbindd socket */
 282
 283 static int read_sock(void *buffer, int count)
 284 {
 285         int result = 0, nread = 0;
 286
 287         /* Read data from socket */
 288
 289         while(nread < count) {
 290
 291                 result = read(winbindd_fd, (char *)buffer + nread,
 292                               count - nread);
 293
 294                 if ((result == -1) || (result == 0)) {
 295
 296                         /* Read failed.  I think the only useful thing we
 297                            can do here is just return -1 and fail since the
 298                            transaction has failed half way through. */
 299
 300                         close_sock();
 301                         return -1;
 302                 }
 303
 304                 nread += result;
 305         }
 306
 307         return result;
 308 }
 309
 310 /* Read reply */
 311
 312 int read_reply(struct winbindd_response *response)
 313 {
 314         int result1, result2 = 0;
 315
 316         if (!response) {
 317                 return -1;
 318         }
 319
 320         /* Read fixed length response */
 321
 322         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 323             == -1) {
 324
 325                 return -1;
 326         }
 327
 328         /* We actually send the pointer value of the extra_data field from
 329            the server.  This has no meaning in the client's address space
 330            so we clear it out. */
 331
 332         response->extra_data = NULL;
 333
 334         /* Read variable length response */
 335
 336         if (response->length > sizeof(struct winbindd_response)) {
 337                 int extra_data_len = response->length -
 338                         sizeof(struct winbindd_response);
 339
 340                 /* Mallocate memory for extra data */
 341
 342                 if (!(response->extra_data = malloc(extra_data_len))) {
 343                         return -1;
 344                 }
 345
 346                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 347                     == -1) {
 348                         free_response(response);
 349                         return -1;
 350                 }
 351         }
 352
 353         /* Return total amount of data read */
 354
 355         return result1 + result2;
 356 }
 357
 358 /*
 359  * send simple types of requests
 360  */
 361
 362 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 363 {
 364         struct winbindd_request lrequest;
 365
 366         /* Check for our tricky environment variable */
 367
 368         if (getenv(WINBINDD_DONT_ENV)) {
 369                 return NSS_STATUS_NOTFOUND;
 370         }
 371
 372         if (!request) {
 373                 ZERO_STRUCT(lrequest);
 374                 request = &lrequest;
 375         }
 376
 377         /* Fill in request and send down pipe */
 378
 379         init_request(request, req_type);
 380
 381         if (write_sock(request, sizeof(*request)) == -1) {
 382                 return NSS_STATUS_UNAVAIL;
 383         }
 384
 385         return NSS_STATUS_SUCCESS;
 386 }
 387
 388 /*
 389  * Get results from winbindd request
 390  */
 391
 392 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 393 {
 394         struct winbindd_response lresponse;
 395
 396         if (!response) {
 397                 ZERO_STRUCT(lresponse);
 398                 response = &lresponse;
 399         }
 400
 401         init_response(response);
 402
 403         /* Wait for reply */
 404         if (read_reply(response) == -1) {
 405                 return NSS_STATUS_UNAVAIL;
 406         }
 407
 408         /* Throw away extra data if client didn't request it */
 409         if (response == &lresponse) {
 410                 free_response(response);
 411         }
 412
 413         /* Copy reply data from socket */
 414         if (response->result != WINBINDD_OK) {
 415                 return NSS_STATUS_NOTFOUND;
 416         }
 417
 418         return NSS_STATUS_SUCCESS;
 419 }
 420
 421 /* Handle simple types of requests */
 422
 423 NSS_STATUS winbindd_request(int req_type,
 424                             struct winbindd_request *request,
 425                             struct winbindd_response *response)
 426 {
 427         NSS_STATUS status;
 428
 429         status = winbindd_send_request(req_type, request);
 430         if (status != NSS_STATUS_SUCCESS)
 431                 return(status);
 432         return winbindd_get_response(response);
 433 }