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_nss_config.h"
  28 #include "winbindd_nss.h"
  29
  30 /* Global variables.  These are effectively the client state information */
  31
  32 int winbindd_fd = -1;           /* fd for winbindd socket */
  33
  34 /* Free a response structure */
  35
  36 void free_response(struct winbindd_response *response)
  37 {
  38         /* Free any allocated extra_data */
  39
  40         if (response)
  41                 SAFE_FREE(response->extra_data);
  42 }
  43
  44 /* Initialise a request structure */
  45
  46 void init_request(struct winbindd_request *request, int request_type)
  47 {
  48         static char *domain_env;
  49         static BOOL initialised;
  50
  51         request->length = sizeof(struct winbindd_request);
  52
  53         request->cmd = (enum winbindd_cmd)request_type;
  54         request->pid = getpid();
  55         request->domain[0] = '\0';
  56
  57         if (!initialised) {
  58                 initialised = True;
  59                 domain_env = getenv(WINBINDD_DOMAIN_ENV);
  60         }
  61
  62         if (domain_env) {
  63                 strncpy(request->domain, domain_env,
  64                         sizeof(request->domain) - 1);
  65                 request->domain[sizeof(request->domain) - 1] = '\0';
  66         }
  67 }
  68
  69 /* Initialise a response structure */
  70
  71 void init_response(struct winbindd_response *response)
  72 {
  73         /* Initialise return value */
  74
  75         response->result = WINBINDD_ERROR;
  76 }
  77
  78 /* Close established socket */
  79
  80 void close_sock(void)
  81 {
  82         if (winbindd_fd != -1) {
  83                 close(winbindd_fd);
  84                 winbindd_fd = -1;
  85         }
  86 }
  87
  88 /* Make sure socket handle isn't stdin, stdout or stderr */
  89 #define RECURSION_LIMIT 3
  90
  91 static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
  92 {
  93         int new_fd;
  94         if (fd >= 0 && fd <= 2) {
  95 #ifdef F_DUPFD
  96                 if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
  97                         return -1;
  98                 }
  99                 /* Parinoia */
 100                 if (new_fd < 3) {
 101                         close(new_fd);
 102                         return -1;
 103                 }
 104                 close(fd);
 105                 return new_fd;
 106 #else
 107                 if (limit <= 0)
 108                         return -1;
 109
 110                 new_fd = dup(fd);
 111                 if (new_fd == -1)
 112                         return -1;
 113
 114                 /* use the program stack to hold our list of FDs to close */
 115                 new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
 116                 close(fd);
 117                 return new_fd;
 118 #endif
 119         }
 120         return fd;
 121 }
 122
 123 static int make_safe_fd(int fd)
 124 {
 125         int result, flags;
 126         int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
 127         if (new_fd == -1) {
 128                 close(fd);
 129                 return -1;
 130         }
 131         /* Socket should be closed on exec() */
 132
 133 #ifdef FD_CLOEXEC
 134         result = flags = fcntl(new_fd, F_GETFD, 0);
 135         if (flags >= 0) {
 136                 flags |= FD_CLOEXEC;
 137                 result = fcntl( new_fd, F_SETFD, flags );
 138         }
 139         if (result < 0) {
 140                 close(new_fd);
 141                 return -1;
 142         }
 143 #endif
 144         return new_fd;
 145 }
 146
 147 /* Connect to winbindd socket */
 148
 149 int winbind_open_pipe_sock(void)
 150 {
 151 #ifdef HAVE_UNIXSOCKET
 152         struct sockaddr_un sunaddr;
 153         static pid_t our_pid;
 154         struct stat st;
 155         pstring path;
 156         int fd;
 157
 158         if (our_pid != getpid()) {
 159                 close_sock();
 160                 our_pid = getpid();
 161         }
 162
 163         if (winbindd_fd != -1) {
 164                 return winbindd_fd;
 165         }
 166
 167         /* Check permissions on unix socket directory */
 168
 169         if (lstat(WINBINDD_SOCKET_DIR, &st) == -1) {
 170                 return -1;
 171         }
 172
 173         if (!S_ISDIR(st.st_mode) ||
 174             (st.st_uid != 0 && st.st_uid != geteuid())) {
 175                 return -1;
 176         }
 177
 178         /* Connect to socket */
 179
 180         strncpy(path, WINBINDD_SOCKET_DIR, sizeof(path) - 1);
 181         path[sizeof(path) - 1] = '\0';
 182
 183         strncat(path, "/", sizeof(path) - 1);
 184         path[sizeof(path) - 1] = '\0';
 185
 186         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1);
 187         path[sizeof(path) - 1] = '\0';
 188
 189         ZERO_STRUCT(sunaddr);
 190         sunaddr.sun_family = AF_UNIX;
 191         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 192
 193         /* If socket file doesn't exist, don't bother trying to connect
 194            with retry.  This is an attempt to make the system usable when
 195            the winbindd daemon is not running. */
 196
 197         if (lstat(path, &st) == -1) {
 198                 return -1;
 199         }
 200
 201         /* Check permissions on unix socket file */
 202
 203         if (!S_ISSOCK(st.st_mode) ||
 204             (st.st_uid != 0 && st.st_uid != geteuid())) {
 205                 return -1;
 206         }
 207
 208         /* Connect to socket */
 209
 210         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 211                 return -1;
 212         }
 213
 214         if ((winbindd_fd = make_safe_fd( fd)) == -1) {
 215                 return winbindd_fd;
 216         }
 217
 218         if (connect(winbindd_fd, (struct sockaddr *)&sunaddr,
 219                     sizeof(sunaddr)) == -1) {
 220                 close_sock();
 221                 return -1;
 222         }
 223
 224         return winbindd_fd;
 225 #else
 226         return -1;
 227 #endif /* HAVE_UNIXSOCKET */
 228 }
 229
 230 /* Write data to winbindd socket */
 231
 232 int write_sock(void *buffer, int count)
 233 {
 234         int result, nwritten;
 235
 236         /* Open connection to winbind daemon */
 237
 238  restart:
 239
 240         if (winbind_open_pipe_sock() == -1) {
 241                 return -1;
 242         }
 243
 244         /* Write data to socket */
 245
 246         nwritten = 0;
 247
 248         while(nwritten < count) {
 249                 struct timeval tv;
 250                 fd_set r_fds;
 251
 252                 /* Catch pipe close on other end by checking if a read()
 253                    call would not block by calling select(). */
 254
 255                 FD_ZERO(&r_fds);
 256                 FD_SET(winbindd_fd, &r_fds);
 257                 ZERO_STRUCT(tv);
 258
 259                 if (select(winbindd_fd + 1, &r_fds, NULL, NULL, &tv) == -1) {
 260                         close_sock();
 261                         return -1;                   /* Select error */
 262                 }
 263
 264                 /* Write should be OK if fd not available for reading */
 265
 266                 if (!FD_ISSET(winbindd_fd, &r_fds)) {
 267
 268                         /* Do the write */
 269
 270                         result = write(winbindd_fd,
 271                                        (char *)buffer + nwritten,
 272                                        count - nwritten);
 273
 274                         if ((result == -1) || (result == 0)) {
 275
 276                                 /* Write failed */
 277
 278                                 close_sock();
 279                                 return -1;
 280                         }
 281
 282                         nwritten += result;
 283
 284                 } else {
 285
 286                         /* Pipe has closed on remote end */
 287
 288                         close_sock();
 289                         goto restart;
 290                 }
 291         }
 292
 293         return nwritten;
 294 }
 295
 296 /* Read data from winbindd socket */
 297
 298 static int read_sock(void *buffer, int count)
 299 {
 300         int result = 0, nread = 0;
 301
 302         /* Read data from socket */
 303
 304         while(nread < count) {
 305
 306                 result = read(winbindd_fd, (char *)buffer + nread,
 307                               count - nread);
 308
 309                 if ((result == -1) || (result == 0)) {
 310
 311                         /* Read failed.  I think the only useful thing we
 312                            can do here is just return -1 and fail since the
 313                            transaction has failed half way through. */
 314
 315                         close_sock();
 316                         return -1;
 317                 }
 318
 319                 nread += result;
 320         }
 321
 322         return result;
 323 }
 324
 325 /* Read reply */
 326
 327 int read_reply(struct winbindd_response *response)
 328 {
 329         int result1, result2 = 0;
 330
 331         if (!response) {
 332                 return -1;
 333         }
 334
 335         /* Read fixed length response */
 336
 337         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 338             == -1) {
 339
 340                 return -1;
 341         }
 342
 343         /* We actually send the pointer value of the extra_data field from
 344            the server.  This has no meaning in the client's address space
 345            so we clear it out. */
 346
 347         response->extra_data = NULL;
 348
 349         /* Read variable length response */
 350
 351         if (response->length > sizeof(struct winbindd_response)) {
 352                 int extra_data_len = response->length -
 353                         sizeof(struct winbindd_response);
 354
 355                 /* Mallocate memory for extra data */
 356
 357                 if (!(response->extra_data = malloc(extra_data_len))) {
 358                         return -1;
 359                 }
 360
 361                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 362                     == -1) {
 363                         free_response(response);
 364                         return -1;
 365                 }
 366         }
 367
 368         /* Return total amount of data read */
 369
 370         return result1 + result2;
 371 }
 372
 373 /*
 374  * send simple types of requests
 375  */
 376
 377 NSS_STATUS winbindd_send_request(int req_type, struct winbindd_request *request)
 378 {
 379         struct winbindd_request lrequest;
 380
 381         /* Check for our tricky environment variable */
 382
 383         if (getenv(WINBINDD_DONT_ENV)) {
 384                 return NSS_STATUS_NOTFOUND;
 385         }
 386
 387         if (!request) {
 388                 ZERO_STRUCT(lrequest);
 389                 request = &lrequest;
 390         }
 391
 392         /* Fill in request and send down pipe */
 393
 394         init_request(request, req_type);
 395
 396         if (write_sock(request, sizeof(*request)) == -1) {
 397                 return NSS_STATUS_UNAVAIL;
 398         }
 399
 400         return NSS_STATUS_SUCCESS;
 401 }
 402
 403 /*
 404  * Get results from winbindd request
 405  */
 406
 407 NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 408 {
 409         struct winbindd_response lresponse;
 410
 411         if (!response) {
 412                 ZERO_STRUCT(lresponse);
 413                 response = &lresponse;
 414         }
 415
 416         init_response(response);
 417
 418         /* Wait for reply */
 419         if (read_reply(response) == -1) {
 420                 return NSS_STATUS_UNAVAIL;
 421         }
 422
 423         /* Throw away extra data if client didn't request it */
 424         if (response == &lresponse) {
 425                 free_response(response);
 426         }
 427
 428         /* Copy reply data from socket */
 429         if (response->result != WINBINDD_OK) {
 430                 return NSS_STATUS_NOTFOUND;
 431         }
 432
 433         return NSS_STATUS_SUCCESS;
 434 }
 435
 436 /* Handle simple types of requests */
 437
 438 NSS_STATUS winbindd_request(int req_type,
 439                             struct winbindd_request *request,
 440                             struct winbindd_response *response)
 441 {
 442         NSS_STATUS status;
 443
 444         status = winbindd_send_request(req_type, request);
 445         if (status != NSS_STATUS_SUCCESS)
 446                 return(status);
 447         return winbindd_get_response(response);
 448 }