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