src/charon-tkm/src/charon-tkm.c

   1 /*
   2  * Copyright (C) 2012 Tobias Brunner
   3  * Copyright (C) 2012 Reto Buerki
   4  * Copyright (C) 2012 Adrian-Ken Rueegsegger
   5  * Hochschule fuer Technik Rapperswil
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2 of the License, or (at your
  10  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * for more details.
  16  */
  17
  18 #define _GNU_SOURCE
  19
  20 #include <stdio.h>
  21 #include <syslog.h>
  22 #include <signal.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26 #include <libgen.h>
  27
  28 #include <hydra.h>
  29 #include <daemon.h>
  30 #include <plugins/kernel_netlink/kernel_netlink_net.h>
  31 #include <library.h>
  32 #include <utils/backtrace.h>
  33 #include <threading/thread.h>
  34 #include <sa/keymat.h>
  35
  36 #include "tkm.h"
  37 #include "tkm_nonceg.h"
  38 #include "tkm_diffie_hellman.h"
  39 #include "tkm_keymat.h"
  40 #include "tkm_listener.h"
  41 #include "tkm_kernel_ipsec.h"
  42
  43 /**
  44  * TKM bus listener for IKE authorize events.
  45  */
  46 static tkm_listener_t *listener;
  47
  48 /**
  49  * PID file, in which charon-tkm stores its process id
  50  */
  51 static char *pidfile_name = NULL;
  52
  53 /**
  54  * Global reference to PID file (required to truncate, if undeletable)
  55  */
  56 static FILE *pidfile = NULL;
  57
  58 /**
  59  * Hook in library for debugging messages
  60  */
  61 extern void (*dbg) (debug_t group, level_t level, char *fmt, ...);
  62
  63 /**
  64  * Simple logging hook for library logs, using syslog output
  65  */
  66 static void dbg_syslog(debug_t group, level_t level, char *fmt, ...)
  67 {
  68         if (level <= 1)
  69         {
  70                 char buffer[8192];
  71                 va_list args;
  72
  73                 va_start(args, fmt);
  74                 /* write in memory buffer first */
  75                 vsnprintf(buffer, sizeof(buffer), fmt, args);
  76                 syslog(LOG_DAEMON|LOG_INFO, "00[%s] %s", debug_names->names[group],
  77                                 buffer);
  78                 va_end(args);
  79         }
  80 }
  81
  82 /**
  83  * Run the daemon and handle unix signals
  84  */
  85 static void run()
  86 {
  87         sigset_t set;
  88
  89         /* handle SIGINT and SIGTERM in this handler */
  90         sigemptyset(&set);
  91         sigaddset(&set, SIGINT);
  92         sigaddset(&set, SIGTERM);
  93         sigprocmask(SIG_BLOCK, &set, NULL);
  94
  95         while (TRUE)
  96         {
  97                 int sig;
  98                 int error;
  99
 100                 error = sigwait(&set, &sig);
 101                 if (error)
 102                 {
 103                         DBG1(DBG_DMN, "error %d while waiting for a signal", error);
 104                         return;
 105                 }
 106                 switch (sig)
 107                 {
 108                         case SIGINT:
 109                         {
 110                                 DBG1(DBG_DMN, "signal of type SIGINT received. Shutting down");
 111                                 charon->bus->alert(charon->bus, ALERT_SHUTDOWN_SIGNAL, sig);
 112                                 return;
 113                         }
 114                         case SIGTERM:
 115                         {
 116                                 DBG1(DBG_DMN, "signal of type SIGTERM received. Shutting down");
 117                                 charon->bus->alert(charon->bus, ALERT_SHUTDOWN_SIGNAL, sig);
 118                                 return;
 119                         }
 120                         default:
 121                         {
 122                                 DBG1(DBG_DMN, "unknown signal %d received. Ignored", sig);
 123                                 break;
 124                         }
 125                 }
 126         }
 127 }
 128
 129 /**
 130  * Handle SIGSEGV/SIGILL signals raised by threads
 131  */
 132 static void segv_handler(int signal)
 133 {
 134         backtrace_t *backtrace;
 135
 136         DBG1(DBG_DMN, "thread %u received %d", thread_current_id(), signal);
 137         backtrace = backtrace_create(2);
 138         backtrace->log(backtrace, stderr, TRUE);
 139         backtrace->destroy(backtrace);
 140
 141         DBG1(DBG_DMN, "killing ourself, received critical signal");
 142         abort();
 143 }
 144
 145 /**
 146  * Lookup UID and GID
 147  */
 148 static bool lookup_uid_gid()
 149 {
 150 #ifdef IPSEC_USER
 151         if (!charon->caps->resolve_uid(charon->caps, IPSEC_USER))
 152         {
 153                 return FALSE;
 154         }
 155 #endif
 156 #ifdef IPSEC_GROUP
 157         if (!charon->caps->resolve_gid(charon->caps, IPSEC_GROUP))
 158         {
 159                 return FALSE;
 160         }
 161 #endif
 162         return TRUE;
 163 }
 164
 165 /**
 166  * Check/create PID file, return TRUE if already running
 167  */
 168 static bool check_pidfile()
 169 {
 170         struct stat stb;
 171
 172         if (stat(pidfile_name, &stb) == 0)
 173         {
 174                 pidfile = fopen(pidfile_name, "r");
 175                 if (pidfile)
 176                 {
 177                         char buf[64];
 178                         pid_t pid = 0;
 179
 180                         memset(buf, 0, sizeof(buf));
 181                         if (fread(buf, 1, sizeof(buf), pidfile))
 182                         {
 183                                 buf[sizeof(buf) - 1] = '\0';
 184                                 pid = atoi(buf);
 185                         }
 186                         fclose(pidfile);
 187                         if (pid && kill(pid, 0) == 0)
 188                         {       /* such a process is running */
 189                                 return TRUE;
 190                         }
 191                 }
 192                 DBG1(DBG_DMN, "removing pidfile '%s', process not running", pidfile_name);
 193                 unlink(pidfile_name);
 194         }
 195
 196         /* create new pidfile */
 197         pidfile = fopen(pidfile_name, "w");
 198         if (pidfile)
 199         {
 200                 ignore_result(fchown(fileno(pidfile),
 201                                                          charon->caps->get_uid(charon->caps),
 202                                                          charon->caps->get_gid(charon->caps)));
 203                 fprintf(pidfile, "%d\n", getpid());
 204                 fflush(pidfile);
 205         }
 206         return FALSE;
 207 }
 208
 209 /**
 210  * Delete/truncate the PID file
 211  */
 212 static void unlink_pidfile()
 213 {
 214         /* because unlinking the PID file may fail, we truncate it to ensure the
 215          * daemon can be properly restarted.  one probable cause for this is the
 216          * combination of not running as root and the effective user lacking
 217          * permissions on the parent dir(s) of the PID file */
 218         if (pidfile)
 219         {
 220                 ignore_result(ftruncate(fileno(pidfile), 0));
 221                 fclose(pidfile);
 222         }
 223         unlink(pidfile_name);
 224 }
 225 /**
 226  * Main function, starts TKM backend.
 227  */
 228 int main(int argc, char *argv[])
 229 {
 230         char *dmn_name;
 231         if (argc > 0 && strlen(argv[0]) > 0)
 232         {
 233                 dmn_name = basename(argv[0]);
 234         }
 235         else
 236         {
 237                 dmn_name = "charon-tkm";
 238         }
 239
 240         struct sigaction action;
 241         int status = SS_RC_INITIALIZATION_FAILED;
 242
 243         /* logging for library during initialization, as we have no bus yet */
 244         dbg = dbg_syslog;
 245
 246         /* initialize library */
 247         if (!library_init(NULL))
 248         {
 249                 library_deinit();
 250                 exit(status);
 251         }
 252
 253         if (!libhydra_init(dmn_name))
 254         {
 255                 dbg_syslog(DBG_DMN, 1, "initialization failed - aborting %s", dmn_name);
 256                 libhydra_deinit();
 257                 library_deinit();
 258                 exit(status);
 259         }
 260
 261         if (!libcharon_init(dmn_name))
 262         {
 263                 dbg_syslog(DBG_DMN, 1, "initialization failed - aborting %s", dmn_name);
 264                 goto deinit;
 265         }
 266
 267         if (!lookup_uid_gid())
 268         {
 269                 dbg_syslog(DBG_DMN, 1, "invalid uid/gid - aborting %s", dmn_name);
 270                 goto deinit;
 271         }
 272
 273         /* make sure we log to the DAEMON facility by default */
 274         lib->settings->set_int(lib->settings, "%s.syslog.daemon.default",
 275                         lib->settings->get_int(lib->settings, "%s.syslog.daemon.default", 1,
 276                                                                    dmn_name), dmn_name);
 277         charon->load_loggers(charon, NULL, FALSE);
 278
 279         DBG1(DBG_DMN, "Starting charon with TKM backend (strongSwan "VERSION")");
 280
 281         /* register TKM specific plugins */
 282         static plugin_feature_t features[] = {
 283                 PLUGIN_REGISTER(NONCE_GEN, tkm_nonceg_create),
 284                         PLUGIN_PROVIDE(NONCE_GEN),
 285                 PLUGIN_REGISTER(DH, tkm_diffie_hellman_create),
 286                         PLUGIN_PROVIDE(DH, MODP_3072_BIT),
 287                         PLUGIN_PROVIDE(DH, MODP_4096_BIT),
 288                 PLUGIN_CALLBACK(kernel_ipsec_register, tkm_kernel_ipsec_create),
 289                         PLUGIN_PROVIDE(CUSTOM, "kernel-ipsec"),
 290                         PLUGIN_DEPENDS(RNG, RNG_WEAK),
 291                 PLUGIN_CALLBACK(kernel_net_register, kernel_netlink_net_create),
 292                         PLUGIN_PROVIDE(CUSTOM, "kernel-net"),
 293
 294         };
 295         lib->plugins->add_static_features(lib->plugins, "tkm-backend", features,
 296                         countof(features), TRUE);
 297
 298         /* register TKM keymat variant */
 299         keymat_register_constructor(IKEV2, (keymat_constructor_t)tkm_keymat_create);
 300
 301         /* initialize daemon */
 302         if (!charon->initialize(charon, PLUGINS))
 303         {
 304                 DBG1(DBG_DMN, "initialization failed - aborting %s", dmn_name);
 305                 goto deinit;
 306         }
 307
 308         /* set global pidfile name depending on daemon name */
 309         if (asprintf(&pidfile_name, IPSEC_PIDDIR"/%s.pid", dmn_name) < 0)
 310         {
 311                 DBG1(DBG_DMN, "unable to set pidfile name - aborting %s", dmn_name);
 312                 goto deinit;
 313         };
 314
 315         if (check_pidfile())
 316         {
 317                 DBG1(DBG_DMN, "%s already running (\"%s\" exists)", dmn_name,
 318                          pidfile_name);
 319                 goto deinit;
 320         }
 321
 322         if (!charon->caps->drop(charon->caps))
 323         {
 324                 DBG1(DBG_DMN, "capability dropping failed - aborting %s", dmn_name);
 325                 goto deinit;
 326         }
 327
 328         /* initialize TKM client */
 329         if (!tkm_init())
 330         {
 331                 DBG1(DBG_DMN, "init of TKM client failed - aborting %s", dmn_name);
 332                 goto deinit;
 333         }
 334
 335         /* register TKM authorization hook */
 336         listener = tkm_listener_create();
 337         charon->bus->add_listener(charon->bus, &listener->listener);
 338
 339         /* add handler for SEGV and ILL,
 340          * INT and TERM are handled by sigwait() in run() */
 341         action.sa_handler = segv_handler;
 342         action.sa_flags = 0;
 343         sigemptyset(&action.sa_mask);
 344         sigaddset(&action.sa_mask, SIGINT);
 345         sigaddset(&action.sa_mask, SIGTERM);
 346         sigaction(SIGSEGV, &action, NULL);
 347         sigaction(SIGILL, &action, NULL);
 348         sigaction(SIGBUS, &action, NULL);
 349         action.sa_handler = SIG_IGN;
 350         sigaction(SIGPIPE, &action, NULL);
 351
 352         pthread_sigmask(SIG_SETMASK, &action.sa_mask, NULL);
 353
 354         /* start daemon (i.e. the threads in the thread-pool) */
 355         charon->start(charon);
 356
 357         /* main thread goes to run loop */
 358         run();
 359
 360         unlink_pidfile();
 361         status = 0;
 362         charon->bus->remove_listener(charon->bus, &listener->listener);
 363         listener->destroy(listener);
 364
 365 deinit:
 366         libcharon_deinit();
 367         libhydra_deinit();
 368         library_deinit();
 369         tkm_deinit();
 370         return status;
 371 }