src/charon/charon.c

   1 /*
   2  * Copyright (C) 2006-2017 Tobias Brunner
   3  * Copyright (C) 2005-2009 Martin Willi
   4  * Copyright (C) 2006 Daniel Roethlisberger
   5  * Copyright (C) 2005 Jan Hutter
   6  * HSR Hochschule fuer Technik Rapperswil
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2 of the License, or (at your
  11  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  * for more details.
  17  */
  18
  19 #include <stdio.h>
  20 #include <signal.h>
  21 #include <pthread.h>
  22 #include <sys/stat.h>
  23 #include <sys/types.h>
  24 #include <sys/utsname.h>
  25 #include <unistd.h>
  26 #include <getopt.h>
  27 #include <fcntl.h>
  28 #include <errno.h>
  29
  30 #include <daemon.h>
  31
  32 #include <library.h>
  33 #include <utils/backtrace.h>
  34 #include <threading/thread.h>
  35
  36 #ifdef ANDROID
  37 #include <private/android_filesystem_config.h> /* for AID_VPN */
  38 #endif
  39
  40 /**
  41  * PID file, in which charon stores its process id
  42  */
  43 #define PID_FILE IPSEC_PIDDIR "/charon.pid"
  44
  45 /**
  46  * Default user and group
  47  */
  48 #ifndef IPSEC_USER
  49 #define IPSEC_USER NULL
  50 #endif
  51
  52 #ifndef IPSEC_GROUP
  53 #define IPSEC_GROUP NULL
  54 #endif
  55
  56 /**
  57  * Global reference to PID file (required to truncate, if undeletable)
  58  */
  59 static FILE *pidfile = NULL;
  60
  61 /**
  62  * hook in library for debugging messages
  63  */
  64 extern void (*dbg) (debug_t group, level_t level, char *fmt, ...);
  65
  66 /**
  67  * Logging hook for library logs, using stderr output
  68  */
  69 static void dbg_stderr(debug_t group, level_t level, char *fmt, ...)
  70 {
  71         va_list args;
  72
  73         if (level <= 1)
  74         {
  75                 va_start(args, fmt);
  76                 fprintf(stderr, "00[%N] ", debug_names, group);
  77                 vfprintf(stderr, fmt, args);
  78                 fprintf(stderr, "\n");
  79                 va_end(args);
  80         }
  81 }
  82
  83 /**
  84  * Run the daemon and handle unix signals
  85  */
  86 static void run()
  87 {
  88         sigset_t set;
  89
  90         /* handle SIGINT, SIGHUP and SIGTERM in this handler */
  91         sigemptyset(&set);
  92         sigaddset(&set, SIGINT);
  93         sigaddset(&set, SIGHUP);
  94         sigaddset(&set, SIGTERM);
  95         sigprocmask(SIG_BLOCK, &set, NULL);
  96
  97         while (TRUE)
  98         {
  99                 int sig;
 100
 101                 sig = sigwaitinfo(&set, NULL);
 102                 if (sig == -1)
 103                 {
 104                         if (errno == EINTR)
 105                         {       /* ignore signals we didn't wait for */
 106                                 continue;
 107                         }
 108                         DBG1(DBG_DMN, "waiting for signal failed: %s", strerror(errno));
 109                         return;
 110                 }
 111                 switch (sig)
 112                 {
 113                         case SIGHUP:
 114                         {
 115                                 DBG1(DBG_DMN, "signal of type SIGHUP received. Reloading "
 116                                          "configuration");
 117                                 if (lib->settings->load_files(lib->settings, lib->conf, FALSE))
 118                                 {
 119                                         charon->load_loggers(charon);
 120                                         lib->plugins->reload(lib->plugins, NULL);
 121                                 }
 122                                 else
 123                                 {
 124                                         DBG1(DBG_DMN, "reloading config failed, keeping old");
 125                                 }
 126                                 break;
 127                         }
 128                         case SIGINT:
 129                         {
 130                                 DBG1(DBG_DMN, "signal of type SIGINT received. Shutting down");
 131                                 charon->bus->alert(charon->bus, ALERT_SHUTDOWN_SIGNAL, sig);
 132                                 return;
 133                         }
 134                         case SIGTERM:
 135                         {
 136                                 DBG1(DBG_DMN, "signal of type SIGTERM received. Shutting down");
 137                                 charon->bus->alert(charon->bus, ALERT_SHUTDOWN_SIGNAL, sig);
 138                                 return;
 139                         }
 140                 }
 141         }
 142 }
 143
 144 /**
 145  * lookup UID and GID
 146  */
 147 static bool lookup_uid_gid()
 148 {
 149         char *name;
 150
 151         name = lib->settings->get_str(lib->settings, "charon.user", IPSEC_USER);
 152         if (name && !lib->caps->resolve_uid(lib->caps, name))
 153         {
 154                 return FALSE;
 155         }
 156         name = lib->settings->get_str(lib->settings, "charon.group", IPSEC_GROUP);
 157         if (name && !lib->caps->resolve_gid(lib->caps, name))
 158         {
 159                 return FALSE;
 160         }
 161 #ifdef ANDROID
 162         lib->caps->set_uid(lib->caps, AID_VPN);
 163 #endif
 164         return TRUE;
 165 }
 166
 167 /**
 168  * Handle SIGSEGV/SIGILL signals raised by threads
 169  */
 170 #ifndef DISABLE_SIGNAL_HANDLER
 171 static void segv_handler(int signal)
 172 {
 173         backtrace_t *backtrace;
 174
 175         DBG1(DBG_DMN, "thread %u received %d", thread_current_id(), signal);
 176         backtrace = backtrace_create(2);
 177         backtrace->log(backtrace, NULL, TRUE);
 178         backtrace->log(backtrace, stderr, TRUE);
 179         backtrace->destroy(backtrace);
 180
 181         DBG1(DBG_DMN, "killing ourself, received critical signal");
 182         abort();
 183 }
 184 #endif /* DISABLE_SIGNAL_HANDLER */
 185
 186 /**
 187  * Check/create PID file, return TRUE if already running
 188  */
 189 static bool check_pidfile()
 190 {
 191         struct stat stb;
 192
 193         if (stat(PID_FILE, &stb) == 0)
 194         {
 195                 pidfile = fopen(PID_FILE, "r");
 196                 if (pidfile)
 197                 {
 198                         char buf[64];
 199                         pid_t pid = 0;
 200
 201                         memset(buf, 0, sizeof(buf));
 202                         if (fread(buf, 1, sizeof(buf), pidfile))
 203                         {
 204                                 buf[sizeof(buf) - 1] = '\0';
 205                                 pid = atoi(buf);
 206                         }
 207                         fclose(pidfile);
 208                         pidfile = NULL;
 209                         if (pid && pid != getpid() && kill(pid, 0) == 0)
 210                         {
 211                                 DBG1(DBG_DMN, "charon already running ('"PID_FILE"' exists)");
 212                                 return TRUE;
 213                         }
 214                 }
 215                 DBG1(DBG_DMN, "removing pidfile '"PID_FILE"', process not running");
 216                 unlink(PID_FILE);
 217         }
 218
 219         /* create new pidfile */
 220         pidfile = fopen(PID_FILE, "w");
 221         if (pidfile)
 222         {
 223                 int fd;
 224
 225                 fd = fileno(pidfile);
 226                 if (fd == -1)
 227                 {
 228                         DBG1(DBG_DMN, "unable to determine fd for '"PID_FILE"'");
 229                         return TRUE;
 230                 }
 231                 if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
 232                 {
 233                         DBG1(DBG_LIB, "setting FD_CLOEXEC for '"PID_FILE"' failed: %s",
 234                                  strerror(errno));
 235                 }
 236                 /* Only change owner of the pidfile if we have CAP_CHOWN. Otherwise,
 237                  * attempt to change group of pidfile to group under which charon
 238                  * runs after dropping caps. This requires the user that charon
 239                  * starts as to:
 240                  * a) Have write access to the socket dir.
 241                  * b) Belong to the group that charon will run under after dropping
 242                  *    caps. */
 243                 if (lib->caps->check(lib->caps, CAP_CHOWN))
 244                 {
 245                         ignore_result(fchown(fd,
 246                                                                  lib->caps->get_uid(lib->caps),
 247                                                                  lib->caps->get_gid(lib->caps)));
 248                 }
 249                 else
 250                 {
 251                         ignore_result(fchown(fd, -1,
 252                                                                  lib->caps->get_gid(lib->caps)));
 253                 }
 254                 fprintf(pidfile, "%d\n", getpid());
 255                 fflush(pidfile);
 256                 return FALSE;
 257         }
 258         else
 259         {
 260                 DBG1(DBG_DMN, "unable to create pidfile '"PID_FILE"'");
 261                 return TRUE;
 262         }
 263 }
 264
 265 /**
 266  * Delete/truncate the PID file
 267  */
 268 static void unlink_pidfile()
 269 {
 270         /* because unlinking the PID file may fail, we truncate it to ensure the
 271          * daemon can be properly restarted.  one probable cause for this is the
 272          * combination of not running as root and the effective user lacking
 273          * permissions on the parent dir(s) of the PID file */
 274         if (pidfile)
 275         {
 276                 ignore_result(ftruncate(fileno(pidfile), 0));
 277                 fclose(pidfile);
 278                 unlink(PID_FILE);
 279         }
 280 }
 281
 282 /**
 283  * print command line usage and exit
 284  */
 285 static void usage(const char *msg)
 286 {
 287         if (msg != NULL && *msg != '\0')
 288         {
 289                 fprintf(stderr, "%s\n", msg);
 290         }
 291         fprintf(stderr, "Usage: charon\n"
 292                                         "         [--help]\n"
 293                                         "         [--version]\n"
 294                                         "         [--use-syslog]\n"
 295                                         "         [--debug-<type> <level>]\n"
 296                                         "           <type>:  log context type (dmn|mgr|ike|chd|job|cfg|knl|net|asn|enc|tnc|imc|imv|pts|tls|esp|lib)\n"
 297                                         "           <level>: log verbosity (-1 = silent, 0 = audit, 1 = control,\n"
 298                                         "                                    2 = controlmore, 3 = raw, 4 = private)\n"
 299                                         "\n"
 300                    );
 301 }
 302
 303 /**
 304  * Main function, starts the daemon.
 305  */
 306 int main(int argc, char *argv[])
 307 {
 308         struct sigaction action;
 309         int group, status = SS_RC_INITIALIZATION_FAILED;
 310         struct utsname utsname;
 311         level_t levels[DBG_MAX];
 312         bool use_syslog = FALSE;
 313
 314         /* logging for library during initialization, as we have no bus yet */
 315         dbg = dbg_stderr;
 316
 317         /* initialize library */
 318         if (!library_init(NULL, "charon"))
 319         {
 320                 library_deinit();
 321                 exit(SS_RC_LIBSTRONGSWAN_INTEGRITY);
 322         }
 323
 324         if (lib->integrity &&
 325                 !lib->integrity->check_file(lib->integrity, "charon", argv[0]))
 326         {
 327                 dbg_stderr(DBG_DMN, 1, "integrity check of charon failed");
 328                 library_deinit();
 329                 exit(SS_RC_DAEMON_INTEGRITY);
 330         }
 331
 332         if (!libcharon_init())
 333         {
 334                 dbg_stderr(DBG_DMN, 1, "initialization failed - aborting charon");
 335                 goto deinit;
 336         }
 337
 338         /* use CTRL loglevel for default */
 339         for (group = 0; group < DBG_MAX; group++)
 340         {
 341                 levels[group] = LEVEL_CTRL;
 342         }
 343
 344         /* handle arguments */
 345         for (;;)
 346         {
 347                 struct option long_opts[] = {
 348                         { "help", no_argument, NULL, 'h' },
 349                         { "version", no_argument, NULL, 'v' },
 350                         { "use-syslog", no_argument, NULL, 'l' },
 351                         /* TODO: handle "debug-all" */
 352                         { "debug-dmn", required_argument, &group, DBG_DMN },
 353                         { "debug-mgr", required_argument, &group, DBG_MGR },
 354                         { "debug-ike", required_argument, &group, DBG_IKE },
 355                         { "debug-chd", required_argument, &group, DBG_CHD },
 356                         { "debug-job", required_argument, &group, DBG_JOB },
 357                         { "debug-cfg", required_argument, &group, DBG_CFG },
 358                         { "debug-knl", required_argument, &group, DBG_KNL },
 359                         { "debug-net", required_argument, &group, DBG_NET },
 360                         { "debug-asn", required_argument, &group, DBG_ASN },
 361                         { "debug-enc", required_argument, &group, DBG_ENC },
 362                         { "debug-tnc", required_argument, &group, DBG_TNC },
 363                         { "debug-imc", required_argument, &group, DBG_IMC },
 364                         { "debug-imv", required_argument, &group, DBG_IMV },
 365                         { "debug-pts", required_argument, &group, DBG_PTS },
 366                         { "debug-tls", required_argument, &group, DBG_TLS },
 367                         { "debug-esp", required_argument, &group, DBG_ESP },
 368                         { "debug-lib", required_argument, &group, DBG_LIB },
 369                         { 0,0,0,0 }
 370                 };
 371
 372                 int c = getopt_long(argc, argv, "", long_opts, NULL);
 373                 switch (c)
 374                 {
 375                         case EOF:
 376                                 break;
 377                         case 'h':
 378                                 usage(NULL);
 379                                 status = 0;
 380                                 goto deinit;
 381                         case 'v':
 382                                 printf("Linux strongSwan %s\n", VERSION);
 383                                 status = 0;
 384                                 goto deinit;
 385                         case 'l':
 386                                 use_syslog = TRUE;
 387                                 continue;
 388                         case 0:
 389                                 /* option is in group */
 390                                 levels[group] = atoi(optarg);
 391                                 continue;
 392                         default:
 393                                 usage("");
 394                                 status = 1;
 395                                 goto deinit;
 396                 }
 397                 break;
 398         }
 399
 400         if (!lookup_uid_gid())
 401         {
 402                 dbg_stderr(DBG_DMN, 1, "invalid uid/gid - aborting charon");
 403                 goto deinit;
 404         }
 405
 406         charon->set_default_loggers(charon, levels, !use_syslog);
 407         charon->load_loggers(charon);
 408
 409         if (uname(&utsname) != 0)
 410         {
 411                 memset(&utsname, 0, sizeof(utsname));
 412         }
 413         DBG1(DBG_DMN, "Starting IKE charon daemon (strongSwan "VERSION", %s %s, %s)",
 414                   utsname.sysname, utsname.release, utsname.machine);
 415         if (lib->integrity)
 416         {
 417                 DBG1(DBG_DMN, "integrity tests enabled:");
 418                 DBG1(DBG_DMN, "lib    'libstrongswan': passed file and segment integrity tests");
 419                 DBG1(DBG_DMN, "lib    'libcharon': passed file and segment integrity tests");
 420                 DBG1(DBG_DMN, "daemon 'charon': passed file integrity test");
 421         }
 422
 423         /* initialize daemon */
 424         if (!charon->initialize(charon,
 425                                 lib->settings->get_str(lib->settings, "charon.load", PLUGINS)))
 426         {
 427                 DBG1(DBG_DMN, "initialization failed - aborting charon");
 428                 goto deinit;
 429         }
 430         lib->plugins->status(lib->plugins, LEVEL_CTRL);
 431
 432         if (check_pidfile())
 433         {
 434                 goto deinit;
 435         }
 436
 437         if (!lib->caps->drop(lib->caps))
 438         {
 439                 DBG1(DBG_DMN, "capability dropping failed - aborting charon");
 440                 goto deinit;
 441         }
 442
 443         /* add handler for fatal signals,
 444          * INT, TERM and HUP are handled by sigwaitinfo() in run() */
 445         action.sa_flags = 0;
 446         sigemptyset(&action.sa_mask);
 447         sigaddset(&action.sa_mask, SIGINT);
 448         sigaddset(&action.sa_mask, SIGTERM);
 449         sigaddset(&action.sa_mask, SIGHUP);
 450
 451         /* optionally let the external system handle fatal signals */
 452 #ifndef DISABLE_SIGNAL_HANDLER
 453         action.sa_handler = segv_handler;
 454         sigaction(SIGSEGV, &action, NULL);
 455         sigaction(SIGILL, &action, NULL);
 456         sigaction(SIGBUS, &action, NULL);
 457 #endif /* DISABLE_SIGNAL_HANDLER */
 458
 459         action.sa_handler = SIG_IGN;
 460         sigaction(SIGPIPE, &action, NULL);
 461
 462         pthread_sigmask(SIG_SETMASK, &action.sa_mask, NULL);
 463
 464         /* start daemon (i.e. the threads in the thread-pool) */
 465         charon->start(charon);
 466
 467         /* main thread goes to run loop */
 468         run();
 469
 470         status = 0;
 471
 472 deinit:
 473         libcharon_deinit();
 474         unlink_pidfile();
 475         library_deinit();
 476         return status;
 477 }