clientserver.c

   1 /* -*- c-file-style: "linux"; -*-
   2
   3    Copyright (C) 1998-2001 by Andrew Tridgell <tridge@samba.org>
   4    Copyright (C) 2001 by Martin Pool <mbp@samba.org>
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 /* the socket based protocol for setting up a connection with rsyncd */
  22
  23 #include "rsync.h"
  24
  25 extern int module_id;
  26 extern int read_only;
  27 extern int verbose;
  28 extern int rsync_port;
  29 char *auth_user;
  30 int sanitize_paths = 0;
  31
  32 /*
  33  * Run a client connected to an rsyncd.  The alternative to this
  34  * function for remote-shell connections is do_cmd.
  35  */
  36 int start_socket_client(char *host, char *path, int argc, char *argv[])
  37 {
  38         int fd, i;
  39         char *sargs[MAX_ARGS];
  40         int sargc=0;
  41         char line[MAXPATHLEN];
  42         char *p, *user=NULL;
  43         extern int remote_version;
  44         extern int am_sender;
  45         extern char *shell_cmd;
  46         extern int kludge_around_eof;
  47         extern char *bind_address;
  48
  49         if (argc == 0 && !am_sender) {
  50                 extern int list_only;
  51                 list_only = 1;
  52         }
  53
  54         /* This is just a friendliness enhancement: if the connection
  55          * is to an rsyncd then there is no point specifying the -e option.
  56          * Note that this is only set if the -e was explicitly specified,
  57          * not if the environment variable just happens to be set.
  58          * See http://lists.samba.org/pipermail/rsync/2000-September/002744.html
  59          */
  60         if (shell_cmd) {
  61                 rprintf(FERROR, "WARNING: --rsh or -e option ignored when "
  62                         "connecting to rsync daemon\n");
  63                 /* continue */
  64         }
  65
  66         if (*path == '/') {
  67                 rprintf(FERROR,"ERROR: The remote path must start with a module name not a /\n");
  68                 return -1;
  69         }
  70
  71         p = strchr(host, '@');
  72         if (p) {
  73                 user = host;
  74                 host = p+1;
  75                 *p = 0;
  76         }
  77
  78         if (!user) user = getenv("USER");
  79         if (!user) user = getenv("LOGNAME");
  80
  81         fd = open_socket_out_wrapped (host, rsync_port, bind_address,
  82                                       global_opts.af_hint);
  83         if (fd == -1) {
  84                 exit_cleanup(RERR_SOCKETIO);
  85         }
  86
  87         server_options(sargs,&sargc);
  88
  89         sargs[sargc++] = ".";
  90
  91         if (path && *path)
  92                 sargs[sargc++] = path;
  93
  94         sargs[sargc] = NULL;
  95
  96         io_printf(fd,"@RSYNCD: %d\n", PROTOCOL_VERSION);
  97
  98         if (!read_line(fd, line, sizeof(line)-1)) {
  99                 return -1;
 100         }
 101
 102         if (sscanf(line,"@RSYNCD: %d", &remote_version) != 1) {
 103                 return -1;
 104         }
 105
 106         p = strchr(path,'/');
 107         if (p) *p = 0;
 108         io_printf(fd,"%s\n",path);
 109         if (p) *p = '/';
 110
 111         /* Old servers may just drop the connection here,
 112          rather than sending a proper EXIT command.  Yuck. */
 113         kludge_around_eof = remote_version < 25;
 114
 115         while (1) {
 116                 if (!read_line(fd, line, sizeof(line)-1)) {
 117                         return -1;
 118                 }
 119
 120                 if (strncmp(line,"@RSYNCD: AUTHREQD ",18) == 0) {
 121                         auth_client(fd, user, line+18);
 122                         continue;
 123                 }
 124
 125                 if (strcmp(line,"@RSYNCD: OK") == 0) break;
 126
 127                 if (strcmp(line,"@RSYNCD: EXIT") == 0) exit(0);
 128
 129                 rprintf(FINFO,"%s\n", line);
 130         }
 131         kludge_around_eof = False;
 132
 133         for (i=0;i<sargc;i++) {
 134                 io_printf(fd,"%s\n", sargs[i]);
 135         }
 136         io_printf(fd,"\n");
 137
 138         if (remote_version < 23) {
 139                 if (remote_version == 22 || (remote_version > 17 && !am_sender))
 140                         io_start_multiplex_in(fd);
 141         }
 142
 143         return client_run(fd, fd, -1, argc, argv);
 144 }
 145
 146
 147
 148 static int rsync_module(int fd, int i)
 149 {
 150         int argc=0;
 151         char *argv[MAX_ARGS];
 152         char **argp;
 153         char line[MAXPATHLEN];
 154         uid_t uid = (uid_t)-2;  /* canonically "nobody" */
 155         gid_t gid = (gid_t)-2;
 156         char *p;
 157         char *addr = client_addr(fd);
 158         char *host = client_name(fd);
 159         char *name = lp_name(i);
 160         int use_chroot = lp_use_chroot(i);
 161         int start_glob=0;
 162         int ret;
 163         char *request=NULL;
 164         extern int am_sender;
 165         extern int remote_version;
 166         extern int am_root;
 167
 168         if (!allow_access(addr, host, lp_hosts_allow(i), lp_hosts_deny(i))) {
 169                 rprintf(FERROR,"rsync denied on module %s from %s (%s)\n",
 170                         name, client_name(fd), client_addr(fd));
 171                 io_printf(fd,"@ERROR: access denied to %s from %s (%s)\n",
 172                           name, client_name(fd), client_addr(fd));
 173                 return -1;
 174         }
 175
 176         if (!claim_connection(lp_lock_file(i), lp_max_connections(i))) {
 177                 if (errno) {
 178                         rprintf(FERROR,"failed to open lock file %s : %s\n",
 179                                 lp_lock_file(i), strerror(errno));
 180                         io_printf(fd,"@ERROR: failed to open lock file %s : %s\n",
 181                                   lp_lock_file(i), strerror(errno));
 182                 } else {
 183                         rprintf(FERROR,"max connections (%d) reached\n",
 184                                 lp_max_connections(i));
 185                         io_printf(fd,"@ERROR: max connections (%d) reached - try again later\n", lp_max_connections(i));
 186                 }
 187                 return -1;
 188         }
 189
 190
 191         auth_user = auth_server(fd, i, addr, "@RSYNCD: AUTHREQD ");
 192
 193         if (!auth_user) {
 194                 rprintf(FERROR,"auth failed on module %s from %s (%s)\n",
 195                         name, client_name(fd), client_addr(fd));
 196                 io_printf(fd,"@ERROR: auth failed on module %s\n",name);
 197                 return -1;
 198         }
 199
 200         module_id = i;
 201
 202         am_root = (getuid() == 0);
 203
 204         if (am_root) {
 205                 p = lp_uid(i);
 206                 if (!name_to_uid(p, &uid)) {
 207                         if (!isdigit(*p)) {
 208                                 rprintf(FERROR,"Invalid uid %s\n", p);
 209                                 io_printf(fd,"@ERROR: invalid uid %s\n", p);
 210                                 return -1;
 211                         }
 212                         uid = atoi(p);
 213                 }
 214
 215                 p = lp_gid(i);
 216                 if (!name_to_gid(p, &gid)) {
 217                         if (!isdigit(*p)) {
 218                                 rprintf(FERROR,"Invalid gid %s\n", p);
 219                                 io_printf(fd,"@ERROR: invalid gid %s\n", p);
 220                                 return -1;
 221                         }
 222                         gid = atoi(p);
 223                 }
 224         }
 225
 226         /* TODO: If we're not root, but the configuration requests
 227          * that we change to some uid other than the current one, then
 228          * log a warning. */
 229
 230         /* TODO: Perhaps take a list of gids, and make them into the
 231          * supplementary groups. */
 232
 233         p = lp_include_from(i);
 234         add_exclude_file(p, 1, 1);
 235
 236         p = lp_include(i);
 237         add_include_line(p);
 238
 239         p = lp_exclude_from(i);
 240         add_exclude_file(p, 1, 0);
 241
 242         p = lp_exclude(i);
 243         add_exclude_line(p);
 244
 245         log_init();
 246
 247         if (use_chroot) {
 248                 /*
 249                  * XXX: The 'use chroot' flag is a fairly reliable
 250                  * source of confusion, because it fails under two
 251                  * important circumstances: running as non-root,
 252                  * running on Win32 (or possibly others).  On the
 253                  * other hand, if you are running as root, then it
 254                  * might be better to always use chroot.
 255                  *
 256                  * So, perhaps if we can't chroot we should just issue
 257                  * a warning, unless a "require chroot" flag is set,
 258                  * in which case we fail.
 259                  */
 260                 if (chroot(lp_path(i))) {
 261                         rsyserr(FERROR, errno, "chroot %s failed", lp_path(i));
 262                         io_printf(fd,"@ERROR: chroot failed\n");
 263                         return -1;
 264                 }
 265
 266                 if (!push_dir("/", 0)) {
 267                         rsyserr(FERROR, errno, "chdir %s failed\n", lp_path(i));
 268                         io_printf(fd,"@ERROR: chdir failed\n");
 269                         return -1;
 270                 }
 271
 272         } else {
 273                 if (!push_dir(lp_path(i), 0)) {
 274                         rsyserr(FERROR, errno, "chdir %s failed\n", lp_path(i));
 275                         io_printf(fd,"@ERROR: chdir failed\n");
 276                         return -1;
 277                 }
 278                 sanitize_paths = 1;
 279         }
 280
 281         if (am_root) {
 282                 if (setgid(gid)) {
 283                         rsyserr(FERROR, errno, "setgid %d failed", (int) gid);
 284                         io_printf(fd,"@ERROR: setgid failed\n");
 285                         return -1;
 286                 }
 287
 288                 if (setuid(uid)) {
 289                         rsyserr(FERROR, errno, "setuid %d failed", (int) uid);
 290                         io_printf(fd,"@ERROR: setuid failed\n");
 291                         return -1;
 292                 }
 293
 294                 am_root = (getuid() == 0);
 295         }
 296
 297         io_printf(fd,"@RSYNCD: OK\n");
 298
 299         argv[argc++] = "rsyncd";
 300
 301         while (1) {
 302                 if (!read_line(fd, line, sizeof(line)-1)) {
 303                         return -1;
 304                 }
 305
 306                 if (!*line) break;
 307
 308                 p = line;
 309
 310                 argv[argc] = strdup(p);
 311                 if (!argv[argc]) {
 312                         return -1;
 313                 }
 314
 315                 if (start_glob) {
 316                         if (start_glob == 1) {
 317                                 request = strdup(p);
 318                                 start_glob++;
 319                         }
 320                         glob_expand(name, argv, &argc, MAX_ARGS);
 321                 } else {
 322                         argc++;
 323                 }
 324
 325                 if (strcmp(line,".") == 0) {
 326                         start_glob = 1;
 327                 }
 328
 329                 if (argc == MAX_ARGS) {
 330                         return -1;
 331                 }
 332         }
 333
 334         if (sanitize_paths) {
 335                 /*
 336                  * Note that this is applied to all parameters, whether or not
 337                  *    they are filenames, but no other legal parameters contain
 338                  *    the forms that need to be sanitized so it doesn't hurt;
 339                  *    it is not known at this point which parameters are files
 340                  *    and which aren't.
 341                  */
 342                 for (i = 1; i < argc; i++) {
 343                         sanitize_path(argv[i], NULL);
 344                 }
 345         }
 346
 347         argp = argv;
 348         ret = parse_arguments(&argc, (const char ***) &argp, 0);
 349
 350         if (request) {
 351                 if (*auth_user) {
 352                         rprintf(FINFO,"rsync %s %s from %s@%s (%s)\n",
 353                                 am_sender?"on":"to",
 354                                 request, auth_user, host, addr);
 355                 } else {
 356                         rprintf(FINFO,"rsync %s %s from %s (%s)\n",
 357                                 am_sender?"on":"to",
 358                                 request, host, addr);
 359                 }
 360                 free(request);
 361         }
 362
 363 #ifndef DEBUG
 364         /* don't allow the logs to be flooded too fast */
 365         if (verbose > 1) verbose = 1;
 366 #endif
 367
 368         if (remote_version < 23) {
 369                 if (remote_version == 22 || (remote_version > 17 && am_sender))
 370                         io_start_multiplex_out(fd);
 371         }
 372
 373         /* For later protocol versions, we don't start multiplexing
 374          * until we've configured nonblocking in start_server.  That
 375          * means we're in a sticky situation now: there's no way to
 376          * convey errors to the client. */
 377
 378         /* FIXME: Hold off on reporting option processing errors until
 379          * we've set up nonblocking and multiplexed IO and can get the
 380          * message back to them. */
 381         if (!ret) {
 382                 option_error();
 383                 exit_cleanup(RERR_UNSUPPORTED);
 384         }
 385
 386         if (lp_timeout(i)) {
 387                 extern int io_timeout;
 388                 io_timeout = lp_timeout(i);
 389         }
 390
 391         start_server(fd, fd, argc, argp);
 392
 393         return 0;
 394 }
 395
 396 /* send a list of available modules to the client. Don't list those
 397    with "list = False". */
 398 static void send_listing(int fd)
 399 {
 400         int n = lp_numservices();
 401         int i;
 402         extern int remote_version;
 403
 404         for (i=0;i<n;i++)
 405                 if (lp_list(i))
 406                     io_printf(fd, "%-15s\t%s\n", lp_name(i), lp_comment(i));
 407
 408         if (remote_version >= 25)
 409                 io_printf(fd,"@RSYNCD: EXIT\n");
 410 }
 411
 412 /* this is called when a socket connection is established to a client
 413    and we want to start talking. The setup of the system is done from
 414    here */
 415 static int start_daemon(int fd)
 416 {
 417         char line[200];
 418         char *motd;
 419         int i = -1;
 420         extern char *config_file;
 421         extern int remote_version;
 422
 423         if (!lp_load(config_file, 0)) {
 424                 exit_cleanup(RERR_SYNTAX);
 425         }
 426
 427         set_socket_options(fd,"SO_KEEPALIVE");
 428         set_socket_options(fd,lp_socket_options());
 429         set_nonblocking(fd);
 430
 431         io_printf(fd,"@RSYNCD: %d\n", PROTOCOL_VERSION);
 432
 433         motd = lp_motd_file();
 434         if (motd && *motd) {
 435                 FILE *f = fopen(motd,"r");
 436                 while (f && !feof(f)) {
 437                         int len = fread(line, 1, sizeof(line)-1, f);
 438                         if (len > 0) {
 439                                 line[len] = 0;
 440                                 io_printf(fd,"%s", line);
 441                         }
 442                 }
 443                 if (f) fclose(f);
 444                 io_printf(fd,"\n");
 445         }
 446
 447         if (!read_line(fd, line, sizeof(line)-1)) {
 448                 return -1;
 449         }
 450
 451         if (sscanf(line,"@RSYNCD: %d", &remote_version) != 1) {
 452                 io_printf(fd,"@ERROR: protocol startup error\n");
 453                 return -1;
 454         }
 455
 456         while (i == -1) {
 457                 line[0] = 0;
 458                 if (!read_line(fd, line, sizeof(line)-1)) {
 459                         return -1;
 460                 }
 461
 462                 if (!*line || strcmp(line,"#list")==0) {
 463                         send_listing(fd);
 464                         return -1;
 465                 }
 466
 467                 if (*line == '#') {
 468                         /* it's some sort of command that I don't understand */
 469                         io_printf(fd,"@ERROR: Unknown command '%s'\n", line);
 470                         return -1;
 471                 }
 472
 473                 i = lp_number(line);
 474                 if (i == -1) {
 475                         io_printf(fd,"@ERROR: Unknown module '%s'\n", line);
 476                         return -1;
 477                 }
 478         }
 479
 480         return rsync_module(fd, i);
 481 }
 482
 483
 484 int daemon_main(void)
 485 {
 486         extern char *config_file;
 487         extern int orig_umask;
 488         char *pid_file;
 489
 490         if (is_a_socket(STDIN_FILENO)) {
 491                 int i;
 492
 493                 /* we are running via inetd - close off stdout and
 494                    stderr so that library functions (and getopt) don't
 495                    try to use them. Redirect them to /dev/null */
 496                 for (i=1;i<3;i++) {
 497                         close(i);
 498                         open("/dev/null", O_RDWR);
 499                 }
 500
 501                 return start_daemon(STDIN_FILENO);
 502         }
 503
 504         if (!global_opts.no_detach)
 505             become_daemon();
 506
 507         if (!lp_load(config_file, 1)) {
 508                 exit_cleanup(RERR_SYNTAX);
 509         }
 510
 511         log_init();
 512
 513         rprintf(FINFO, "rsyncd version %s starting, listening on port %d\n",
 514                 RSYNC_VERSION,
 515                 rsync_port);
 516         /* TODO: If listening on a particular address, then show that
 517          * address too.  In fact, why not just do inet_ntop on the
 518          * local address??? */
 519
 520         if (((pid_file = lp_pid_file()) != NULL) && (*pid_file != '\0')) {
 521                 char pidbuf[16];
 522                 int fd;
 523                 int pid = (int) getpid();
 524                 cleanup_set_pid(pid);
 525                 if ((fd = do_open(lp_pid_file(), O_WRONLY|O_CREAT|O_TRUNC,
 526                                         0666 & ~orig_umask)) == -1) {
 527                     cleanup_set_pid(0);
 528                     rsyserr(FLOG, errno, "failed to create pid file %s", pid_file);
 529                     exit_cleanup(RERR_FILEIO);
 530                 }
 531                 snprintf(pidbuf, sizeof(pidbuf), "%d\n", pid);
 532                 write(fd, pidbuf, strlen(pidbuf));
 533                 close(fd);
 534         }
 535
 536         start_accept_loop(rsync_port, start_daemon);
 537         return -1;
 538 }
 539