/* $OpenBSD: main.c,v 1.59 2024/08/23 00:43:34 millert Exp $ */ /* * main.c - Point-to-Point Protocol main module * * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The name "Carnegie Mellon University" must not be used to * endorse or promote products derived from this software without * prior written permission. For permission or any legal * details, please contact * Office of Technology Transfer * Carnegie Mellon University * 5000 Forbes Avenue * Pittsburgh, PA 15213-3890 * (412) 268-4387, fax: (412) 268-7395 * tech-transfer@andrew.cmu.edu * * 4. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by Computing Services * at Carnegie Mellon University (http://www.cmu.edu/computing/)." * * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pppd.h" #include "magic.h" #include "fsm.h" #include "lcp.h" #include "ipcp.h" #include "upap.h" #include "chap.h" #include "ccp.h" #include "pathnames.h" #include "patchlevel.h" #ifdef CBCP_SUPPORT #include "cbcp.h" #endif #if defined(SUNOS4) extern char *strerror(); #endif #ifdef AT_CHANGE #include "atcp.h" #endif /* interface vars */ char ifname[IFNAMSIZ]; /* Interface name */ int ifunit; /* Interface unit number */ char hostname[HOST_NAME_MAX+1]; /* Our hostname */ static char default_devnam[PATH_MAX]; /* name of default device */ static pid_t pid; /* Our pid */ static uid_t uid; /* Our real user-id */ static int conn_running; /* we have a [dis]connector running */ static volatile sig_atomic_t crashed = 0; int ttyfd = -1; /* Serial port file descriptor */ mode_t tty_mode = -1; /* Original access permissions to tty */ int baud_rate; /* Actual bits/second for serial device */ int hungup; /* terminal has been hung up */ int privileged; /* we're running as real uid root */ int need_holdoff; /* need holdoff period before restarting */ int detached; /* have detached from terminal */ int phase; /* where the link is at */ volatile sig_atomic_t kill_link; volatile sig_atomic_t open_ccp_flag; volatile sig_atomic_t got_sigchld; char **script_env; /* Env. variable values for scripts */ int s_env_nalloc; /* # words avail at script_env */ u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */ u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */ static int locked; /* lock() has succeeded */ char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n"; /* Prototypes for procedures local to this file. */ static void cleanup(void); static void close_tty(void); static void get_input(void); static void calltimeout(void); static struct timeval *timeleft(struct timeval *); static void kill_my_pg(int); static void hup(int); static void term(int); static void chld(int); static void toggle_debug(int); static void open_ccp(int); static void bad_signal(int); static void holdoff_end(void *); static int device_script(char *, int, int); static void reap_kids(void); static void pr_log(void *, char *, ...); extern char *ttyname(int); extern char *getlogin(void); int main(int, char *[]); #ifdef ultrix #undef O_NONBLOCK #define O_NONBLOCK O_NDELAY #endif #ifdef ULTRIX #define setlogmask(x) #endif /* * PPP Data Link Layer "protocol" table. * One entry per supported protocol. * The last entry must be NULL. */ struct protent *protocols[] = { &lcp_protent, &pap_protent, &chap_protent, #ifdef CBCP_SUPPORT &cbcp_protent, #endif &ipcp_protent, &ccp_protent, #ifdef AT_CHANGE &atcp_protent, #endif NULL }; int main(int argc, char *argv[]) { int i, fdflags; struct sigaction sa; char *p; struct passwd *pw; struct timeval timo; sigset_t mask; struct protent *protp; struct stat statbuf; char numbuf[16]; phase = PHASE_INITIALIZE; p = ttyname(0); if (p) strlcpy(devnam, p, PATH_MAX); strlcpy(default_devnam, devnam, sizeof default_devnam); script_env = NULL; /* Initialize syslog facilities */ #ifdef ULTRIX openlog("pppd", LOG_PID); #else openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP); setlogmask(LOG_UPTO(LOG_INFO)); #endif if (gethostname(hostname, sizeof hostname) < 0 ) { option_error("Couldn't get hostname: %m"); die(1); } uid = getuid(); privileged = uid == 0; snprintf(numbuf, sizeof numbuf, "%u", uid); script_setenv("UID", numbuf); /* * Initialize to the standard option set, then parse, in order, * the system options file, the user's options file, * the tty's options file, and the command line arguments. */ for (i = 0; (protp = protocols[i]) != NULL; ++i) (*protp->init)(0); if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1) || !options_from_user()) exit(1); scan_args(argc-1, argv+1); /* look for tty name on command line */ if (!options_for_tty() || !parse_args(argc-1, argv+1)) exit(1); /* * Check that we are running as root. */ if (geteuid() != 0) { option_error("must be root to run %s, since it is not setuid-root", argv[0]); die(1); } if (!ppp_available()) { option_error(no_ppp_msg); exit(1); } /* * Check that the options given are valid and consistent. */ sys_check_options(); auth_check_options(); for (i = 0; (protp = protocols[i]) != NULL; ++i) if (protp->check_options != NULL) (*protp->check_options)(); if (demand && connector == 0) { option_error("connect script required for demand-dialling\n"); exit(1); } script_setenv("DEVICE", devnam); snprintf(numbuf, sizeof numbuf, "%d", baud_rate); script_setenv("SPEED", numbuf); /* * If the user has specified the default device name explicitly, * pretend they hadn't. */ if (!default_device && strcmp(devnam, default_devnam) == 0) default_device = 1; if (default_device) nodetach = 1; /* * Initialize system-dependent stuff and magic number package. */ sys_init(); magic_init(); if (debug) setlogmask(LOG_UPTO(LOG_DEBUG)); /* * Detach ourselves from the terminal, if required, * and identify who is running us. */ if (nodetach == 0) detach(); pid = getpid(); p = getlogin(); if (p == NULL) { pw = getpwuid(uid); if (pw != NULL && pw->pw_name != NULL) p = pw->pw_name; else p = "(unknown)"; } syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %u", VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid); /* * Compute mask of all interesting signals and install signal handlers * for each. Only one signal handler may be active at a time. Therefore, * all other signals should be masked when any handler is executing. */ sigemptyset(&mask); sigaddset(&mask, SIGHUP); sigaddset(&mask, SIGINT); sigaddset(&mask, SIGTERM); sigaddset(&mask, SIGCHLD); #define SIGNAL(s, handler) { \ sa.sa_handler = handler; \ if (sigaction(s, &sa, NULL) < 0) { \ syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \ die(1); \ } \ } sa.sa_mask = mask; sa.sa_flags = 0; SIGNAL(SIGHUP, hup); /* Hangup */ SIGNAL(SIGINT, term); /* Interrupt */ SIGNAL(SIGTERM, term); /* Terminate */ SIGNAL(SIGCHLD, chld); SIGNAL(SIGUSR1, toggle_debug); /* Toggle debug flag */ SIGNAL(SIGUSR2, open_ccp); /* Reopen CCP */ /* * Install a handler for other signals which would otherwise * cause pppd to exit without cleaning up. */ SIGNAL(SIGABRT, bad_signal); SIGNAL(SIGALRM, bad_signal); SIGNAL(SIGFPE, bad_signal); SIGNAL(SIGILL, bad_signal); SIGNAL(SIGPIPE, bad_signal); SIGNAL(SIGQUIT, bad_signal); #if SIGSEGV_CHECK SIGNAL(SIGSEGV, bad_signal); #endif #ifdef SIGBUS SIGNAL(SIGBUS, bad_signal); #endif #ifdef SIGEMT SIGNAL(SIGEMT, bad_signal); #endif #ifdef SIGPOLL SIGNAL(SIGPOLL, bad_signal); #endif #ifdef SIGPROF SIGNAL(SIGPROF, bad_signal); #endif #ifdef SIGSYS SIGNAL(SIGSYS, bad_signal); #endif #ifdef SIGTRAP SIGNAL(SIGTRAP, bad_signal); #endif #ifdef SIGVTALRM SIGNAL(SIGVTALRM, bad_signal); #endif #ifdef SIGXCPU SIGNAL(SIGXCPU, bad_signal); #endif #ifdef SIGXFSZ SIGNAL(SIGXFSZ, bad_signal); #endif /* * Apparently we can get a SIGPIPE when we call syslog, if * syslogd has died and been restarted. Ignoring it seems * be sufficient. */ signal(SIGPIPE, SIG_IGN); /* * If we're doing dial-on-demand, set up the interface now. */ if (demand) { /* * Open the loopback channel and set it up to be the ppp interface. */ open_ppp_loopback(); syslog(LOG_INFO, "Using interface ppp%d", ifunit); (void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit); script_setenv("IFNAME", ifname); /* * Configure the interface and mark it up, etc. */ demand_conf(); } for (;;) { need_holdoff = 1; if (demand) { /* * Don't do anything until we see some activity. */ phase = PHASE_DORMANT; kill_link = 0; demand_unblock(); for (;;) { wait_loop_output(timeleft(&timo)); calltimeout(); if (kill_link) { if (!persist) die(0); kill_link = 0; } if (get_loop_output()) break; reap_kids(); } /* * Now we want to bring up the link. */ demand_drop(); syslog(LOG_INFO, "Starting link"); } /* * Lock the device if we've been asked to. */ if (lockflag && !default_device) { if (lock(devnam) < 0) goto fail; locked = 1; } /* * Open the serial device and set it up to be the ppp interface. * First we open it in non-blocking mode so we can set the * various termios flags appropriately. If we aren't dialling * out and we want to use the modem lines, we reopen it later * in order to wait for the carrier detect signal from the modem. */ while ((ttyfd = open(devnam, O_NONBLOCK | O_RDWR)) < 0) { if (errno != EINTR) syslog(LOG_ERR, "Failed to open %s: %m", devnam); if (!persist || errno != EINTR) goto fail; } if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1 || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0) syslog(LOG_WARNING, "Couldn't reset non-blocking mode on device: %m"); hungup = 0; kill_link = 0; /* * Do the equivalent of `mesg n' to stop broadcast messages. */ if (fstat(ttyfd, &statbuf) < 0 || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) { syslog(LOG_WARNING, "Couldn't restrict write permissions to %s: %m", devnam); } else tty_mode = statbuf.st_mode; /* run connection script */ if (connector && connector[0]) { MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector)); /* * Set line speed, flow control, etc. * On most systems we set CLOCAL for now so that we can talk * to the modem before carrier comes up. But this has the * side effect that we might miss it if CD drops before we * get to clear CLOCAL below. On systems where we can talk * successfully to the modem with CLOCAL clear and CD down, * we can clear CLOCAL at this point. */ set_up_tty(ttyfd, (modem_chat == 0)); /* drop dtr to hang up in case modem is off hook */ if (!default_device && modem) { setdtr(ttyfd, FALSE); sleep(1); setdtr(ttyfd, TRUE); } if (device_script(connector, ttyfd, ttyfd) < 0) { syslog(LOG_ERR, "Connect script failed"); setdtr(ttyfd, FALSE); goto fail; } syslog(LOG_INFO, "Serial connection established."); sleep(1); /* give it time to set up its terminal */ } set_up_tty(ttyfd, 0); /* reopen tty if necessary to wait for carrier */ if (connector == NULL && modem) { while ((i = open(devnam, O_RDWR)) < 0) { if (errno != EINTR) syslog(LOG_ERR, "Failed to reopen %s: %m", devnam); if (!persist || errno != EINTR || hungup || kill_link) goto fail; } close(i); } /* run welcome script, if any */ if (welcomer && welcomer[0]) { if (device_script(welcomer, ttyfd, ttyfd) < 0) syslog(LOG_WARNING, "Welcome script failed"); } /* set up the serial device as a ppp interface */ establish_ppp(ttyfd); if (!demand) { syslog(LOG_INFO, "Using interface ppp%d", ifunit); (void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit); script_setenv("IFNAME", ifname); } /* * Start opening the connection and wait for * incoming events (reply, timeout, etc.). */ syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam); lcp_lowerup(0); lcp_open(0); /* Start protocol */ for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) { wait_input(timeleft(&timo)); calltimeout(); get_input(); if (kill_link) { lcp_close(0, "User request"); kill_link = 0; } if (open_ccp_flag) { if (phase == PHASE_NETWORK) { ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */ (*ccp_protent.open)(0); } open_ccp_flag = 0; } reap_kids(); /* Don't leave dead kids lying around */ } /* * If we may want to bring the link up again, transfer * the ppp unit back to the loopback. Set the * real serial device back to its normal mode of operation. */ clean_check(); if (demand) restore_loop(); disestablish_ppp(ttyfd); /* * Run disconnector script, if requested. * XXX we may not be able to do this if the line has hung up! */ if (disconnector && !hungup) { set_up_tty(ttyfd, 1); if (device_script(disconnector, ttyfd, ttyfd) < 0) { syslog(LOG_WARNING, "disconnect script failed"); } else { syslog(LOG_INFO, "Serial link disconnected."); } } fail: if (ttyfd >= 0) close_tty(); if (locked) { unlock(); locked = 0; } if (!persist) die(1); if (holdoff > 0 && need_holdoff) { phase = PHASE_HOLDOFF; TIMEOUT(holdoff_end, NULL, holdoff); do { wait_time(timeleft(&timo)); calltimeout(); if (kill_link) { if (!persist) die(0); kill_link = 0; phase = PHASE_DORMANT; /* allow signal to end holdoff */ } reap_kids(); } while (phase == PHASE_HOLDOFF); } } die(0); return 0; } /* * detach - detach us from the controlling terminal. */ void detach(void) { if (detached) return; if (daemon(0, 0) < 0) { perror("Couldn't detach from controlling terminal"); die(1); } detached = 1; pid = getpid(); } /* * holdoff_end - called via a timeout when the holdoff period ends. */ static void holdoff_end(void *arg) { phase = PHASE_DORMANT; } /* * get_input - called when incoming data is available. */ static void get_input(void) { int len, i; u_char *p; u_short protocol; struct protent *protp; p = inpacket_buf; /* point to beginning of packet buffer */ len = read_packet(inpacket_buf); if (len < 0) return; if (len == 0) { syslog(LOG_NOTICE, "Modem hangup"); hungup = 1; lcp_lowerdown(0); /* serial link is no longer available */ link_terminated(0); return; } if (debug /*&& (debugflags & DBG_INPACKET)*/) log_packet(p, len, "rcvd ", LOG_DEBUG); if (len < PPP_HDRLEN) { MAINDEBUG((LOG_INFO, "io(): Received short packet.")); return; } p += 2; /* Skip address and control */ GETSHORT(protocol, p); len -= PPP_HDRLEN; /* * Toss all non-LCP packets unless LCP is OPEN. */ if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) { MAINDEBUG((LOG_INFO, "get_input: Received non-LCP packet when LCP not open.")); return; } /* * Until we get past the authentication phase, toss all packets * except LCP, LQR and authentication packets. */ if (phase <= PHASE_AUTHENTICATE && !(protocol == PPP_LCP || protocol == PPP_LQR || protocol == PPP_PAP || protocol == PPP_CHAP)) { MAINDEBUG((LOG_INFO, "get_input: discarding proto 0x%x in phase %d", protocol, phase)); return; } /* * Upcall the proper protocol input routine. */ for (i = 0; (protp = protocols[i]) != NULL; ++i) { if (protp->protocol == protocol && protp->enabled_flag) { (*protp->input)(0, p, len); return; } if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag && protp->datainput != NULL) { (*protp->datainput)(0, p, len); return; } } if (debug) syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol); lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN); } /* * quit - Clean up state and exit (with an error indication). */ void quit(void) { die(1); } /* * die - like quit, except we can specify an exit status. */ void die(int status) { struct syslog_data sdata = SYSLOG_DATA_INIT; cleanup(); syslog_r(LOG_INFO, &sdata, "Exit."); _exit(status); } /* * cleanup - restore anything which needs to be restored before we exit */ static void cleanup(void) { sys_cleanup(); if (ttyfd >= 0) close_tty(); if (locked) unlock(); } /* * close_tty - restore the terminal device and close it. */ static void close_tty(void) { disestablish_ppp(ttyfd); /* drop dtr to hang up */ if (modem) { setdtr(ttyfd, FALSE); /* * This sleep is in case the serial port has CLOCAL set by default, * and consequently will reassert DTR when we close the device. */ sleep(1); } restore_tty(ttyfd); if (tty_mode != (mode_t) -1) fchmod(ttyfd, tty_mode); close(ttyfd); ttyfd = -1; } struct callout { struct timeval c_time; /* time at which to call routine */ void *c_arg; /* argument to routine */ void (*c_func)(void *); /* routine */ struct callout *c_next; }; static struct callout *callout = NULL; /* Callout list */ static struct timeval timenow; /* Current time */ /* * timeout - Schedule a timeout. * * Note that this timeout takes the number of seconds, NOT hz (as in * the kernel). */ void timeout(void (*func)(void *), void *arg, int time) { struct callout *newp, *p, **pp; MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.", (long) func, (long) arg, time)); /* * Allocate timeout. */ if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) { syslog(LOG_ERR, "Out of memory in timeout()!"); die(1); } newp->c_arg = arg; newp->c_func = func; gettimeofday(&timenow, NULL); newp->c_time.tv_sec = timenow.tv_sec + time; newp->c_time.tv_usec = timenow.tv_usec; /* * Find correct place and link it in. */ for (pp = &callout; (p = *pp); pp = &p->c_next) if (newp->c_time.tv_sec < p->c_time.tv_sec || (newp->c_time.tv_sec == p->c_time.tv_sec && newp->c_time.tv_usec < p->c_time.tv_sec)) break; newp->c_next = p; *pp = newp; } /* * untimeout - Unschedule a timeout. */ void untimeout(void (*func)(void *), void *arg) { struct callout **copp, *freep; MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg)); /* * Find first matching timeout and remove it from the list. */ for (copp = &callout; (freep = *copp); copp = &freep->c_next) if (freep->c_func == func && freep->c_arg == arg) { *copp = freep->c_next; (void) free((char *) freep); break; } } /* * calltimeout - Call any timeout routines which are now due. */ static void calltimeout(void) { struct callout *p; while (callout != NULL) { p = callout; if (gettimeofday(&timenow, NULL) < 0) { syslog(LOG_ERR, "Failed to get time of day: %m"); die(1); } if (!(p->c_time.tv_sec < timenow.tv_sec || (p->c_time.tv_sec == timenow.tv_sec && p->c_time.tv_usec <= timenow.tv_usec))) break; /* no, it's not time yet */ callout = p->c_next; (*p->c_func)(p->c_arg); free((char *) p); } } /* * timeleft - return the length of time until the next timeout is due. */ static struct timeval * timeleft(struct timeval *tvp) { if (callout == NULL) return NULL; gettimeofday(&timenow, NULL); tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec; tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec; if (tvp->tv_usec < 0) { tvp->tv_usec += 1000000; tvp->tv_sec -= 1; } if (tvp->tv_sec < 0) tvp->tv_sec = tvp->tv_usec = 0; return tvp; } /* * kill_my_pg - send a signal to our process group, and ignore it ourselves. */ static void kill_my_pg(int sig) { struct sigaction act, oldact; act.sa_handler = SIG_IGN; act.sa_flags = 0; kill(0, sig); sigaction(sig, &act, &oldact); sigaction(sig, &oldact, NULL); } /* * hup - Catch SIGHUP signal. * * Indicates that the physical layer has been disconnected. * We don't rely on this indication; if the user has sent this * signal, we just take the link down. */ static void hup(int sig) { int save_errno = errno; struct syslog_data sdata = SYSLOG_DATA_INIT; if (crashed) _exit(127); syslog_r(LOG_INFO, &sdata, "Hangup (SIGHUP)"); kill_link = 1; if (conn_running) /* Send the signal to the [dis]connector process(es) also */ kill_my_pg(sig); errno = save_errno; } /* * term - Catch SIGTERM signal and SIGINT signal (^C/del). * * Indicates that we should initiate a graceful disconnect and exit. */ static void term(int sig) { int save_errno = errno; struct syslog_data sdata = SYSLOG_DATA_INIT; if (crashed) _exit(127); syslog_r(LOG_INFO, &sdata, "Terminating on signal %d.", sig); persist = 0; /* don't try to restart */ kill_link = 1; if (conn_running) /* Send the signal to the [dis]connector process(es) also */ kill_my_pg(sig); errno = save_errno; } /* * chld - Catch SIGCHLD signal. * Calls reap_kids to get status for any dead kids. */ static void chld(int sig) { got_sigchld = 1; } /* * toggle_debug - Catch SIGUSR1 signal. * * Toggle debug flag. */ static void toggle_debug(int sig) { debug = !debug; if (debug) { setlogmask(LOG_UPTO(LOG_DEBUG)); /* XXX safe, but wrong */ } else { setlogmask(LOG_UPTO(LOG_WARNING)); /* XXX safe, but wrong */ } } /* * open_ccp - Catch SIGUSR2 signal. * * Try to (re)negotiate compression. */ static void open_ccp(int sig) { open_ccp_flag = 1; } /* * bad_signal - We've caught a fatal signal. Clean up state and exit. */ static void bad_signal(int sig) { struct syslog_data sdata = SYSLOG_DATA_INIT; if (crashed) _exit(127); crashed = 1; syslog_r(LOG_ERR, &sdata, "Fatal signal %d", sig); if (conn_running) kill_my_pg(SIGTERM); die(1); /* XXX unsafe! */ } /* * device_script - run a program to connect or disconnect the * serial device. */ static int device_script(char *program, int in, int out) { pid_t pid; int status; int errfd; gid_t gid; uid_t uid; conn_running = 1; pid = fork(); if (pid < 0) { conn_running = 0; syslog(LOG_ERR, "Failed to create child process: %m"); die(1); } if (pid == 0) { sys_close(); closelog(); if (in == out) { if (in != 0) { dup2(in, 0); close(in); } dup2(0, 1); } else { if (out == 0) out = dup(out); if (in != 0) { dup2(in, 0); close(in); } if (out != 1) { dup2(out, 1); close(out); } } if (nodetach == 0) { close(2); errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600); if (errfd >= 0 && errfd != 2) { dup2(errfd, 2); close(errfd); } } /* revoke privs */ gid = getgid(); uid = getuid(); if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) { syslog(LOG_ERR, "revoke privileges: %s", strerror(errno)); _exit(1); } execl("/bin/sh", "sh", "-c", program, (char *)NULL); syslog(LOG_ERR, "could not exec /bin/sh: %m"); _exit(99); /* NOTREACHED */ } while (waitpid(pid, &status, 0) < 0) { if (errno == EINTR) continue; syslog(LOG_ERR, "error waiting for (dis)connection process: %m"); die(1); } conn_running = 0; return (status == 0 ? 0 : -1); } /* * run-program - execute a program with given arguments, * but don't wait for it. * If the program can't be executed, logs an error unless * must_exist is 0 and the program file doesn't exist. */ int run_program(char *prog, char **args, int must_exist) { pid_t pid; uid_t uid; gid_t gid; pid = fork(); if (pid == -1) { syslog(LOG_ERR, "Failed to create child process for %s: %m", prog); return -1; } if (pid == 0) { int new_fd; /* Leave the current location */ (void) setsid(); /* No controlling tty. */ (void) umask (S_IRWXG|S_IRWXO); (void) chdir ("/"); /* no current directory. */ /* revoke privs */ uid = getuid(); gid = getgid(); if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) { syslog(LOG_ERR, "revoke privileges: %s", strerror(errno)); _exit(1); } /* Ensure that nothing of our device environment is inherited. */ sys_close(); closelog(); close (0); close (1); close (2); close (ttyfd); /* tty interface to the ppp device */ /* Don't pass handles to the PPP device, even by accident. */ new_fd = open (_PATH_DEVNULL, O_RDWR); if (new_fd >= 0) { if (new_fd != 0) { dup2 (new_fd, 0); /* stdin <- /dev/null */ close (new_fd); } dup2 (0, 1); /* stdout -> /dev/null */ dup2 (0, 2); /* stderr -> /dev/null */ } /* Force the priority back to zero if pppd is running higher. */ if (setpriority (PRIO_PROCESS, 0, 0) < 0) syslog (LOG_WARNING, "can't reset priority to 0: %m"); /* SysV recommends a second fork at this point. */ /* run the program; give it a null environment */ execve(prog, args, script_env); if (must_exist || errno != ENOENT) syslog(LOG_WARNING, "Can't execute %s: %m", prog); _exit(1); } MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %ld", prog, (long)pid)); return 0; } /* * reap_kids - get status from any dead child processes, * and log a message for abnormal terminations. */ static void reap_kids(void) { int status; pid_t pid; if (!got_sigchld) return; got_sigchld = 0; for (;;) { pid = waitpid(-1, &status, WNOHANG); switch (pid) { case -1: if (errno == EINTR) continue; if (errno != ECHILD) syslog(LOG_ERR, "Error waiting for child process: %m"); return; case 0: /* No children left */ return; default: if (WIFSIGNALED(status)) { syslog(LOG_WARNING, "Child process %d terminated with signal %d", (int)pid, WTERMSIG(status)); } break; } } } /* * log_packet - format a packet and log it. */ char line[256]; /* line to be logged accumulated here */ char *linep; void log_packet(u_char *p, int len, char *prefix, int level) { strlcpy(line, prefix, sizeof line); linep = line + strlen(line); format_packet(p, len, pr_log, NULL); if (linep != line) syslog(level, "%s", line); } /* * format_packet - make a readable representation of a packet, * calling `printer(arg, format, ...)' to output it. */ void format_packet(u_char *p, int len, void (*printer)(void *, char *, ...), void *arg) { int i, n; u_short proto; u_char x; struct protent *protp; if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) { p += 2; GETSHORT(proto, p); len -= PPP_HDRLEN; for (i = 0; (protp = protocols[i]) != NULL; ++i) if (proto == protp->protocol) break; if (protp != NULL) { printer(arg, "[%s", protp->name); n = (*protp->printpkt)(p, len, printer, arg); printer(arg, "]"); p += n; len -= n; } else { printer(arg, "[proto=0x%x]", proto); } } for (; len > 0; --len) { GETCHAR(x, p); printer(arg, " %.2x", x); } } static void pr_log(void *arg, char *fmt, ...) { int n; va_list pvar; char buf[256]; va_start(pvar, fmt); n = vfmtmsg(buf, sizeof(buf), fmt, pvar); va_end(pvar); if (linep + n + 1 > line + sizeof(line)) { syslog(LOG_DEBUG, "%s", line); linep = line; } strlcpy(linep, buf, line + sizeof line - linep); linep += n; } /* * print_string - print a readable representation of a string using * printer. */ void print_string(char *p, int len, void (*printer)(void *, char *, ...), void *arg) { int c; printer(arg, "\""); for (; len > 0; --len) { c = *p++; if (' ' <= c && c <= '~') { if (c == '\\' || c == '"') printer(arg, "\\"); printer(arg, "%c", c); } else { switch (c) { case '\n': printer(arg, "\\n"); break; case '\r': printer(arg, "\\r"); break; case '\t': printer(arg, "\\t"); break; default: printer(arg, "\\%.3o", c); } } } printer(arg, "\""); } /* * novm - log an error message saying we ran out of memory, and die. */ void novm(char *msg) { syslog(LOG_ERR, "Virtual memory exhausted allocating %s", msg); die(1); } /* * fmtmsg - format a message into a buffer. Like snprintf except we * also specify the length of the output buffer, and we handle * %m (error message) and %I (IP address) formats. * Doesn't do floating-point formats. * Returns the number of chars put into buf. */ int fmtmsg(char *buf, int buflen, char *fmt, ...) { va_list args; int n; va_start(args, fmt); n = vfmtmsg(buf, buflen, fmt, args); va_end(args); return n; } /* * vfmtmsg - like fmtmsg, takes a va_list instead of a list of args. */ #define OUTCHAR(c) (buflen > 0? (--buflen, *buf++ = (c)): 0) int vfmtmsg(char *buf, int buflen, char *fmt, va_list args) { int c, i, n; int width, prec, fillch; int base, len, neg, quoted; unsigned long val = 0; char *str, *f, *buf0; unsigned char *p; char num[32]; time_t t; static char hexchars[] = "0123456789abcdef"; buf0 = buf; --buflen; while (buflen > 0) { for (f = fmt; *f != '%' && *f != 0; ++f) ; if (f > fmt) { len = f - fmt; if (len > buflen) len = buflen; memcpy(buf, fmt, len); buf += len; buflen -= len; fmt = f; } if (*fmt == 0) break; c = *++fmt; width = prec = 0; fillch = ' '; if (c == '0') { fillch = '0'; c = *++fmt; } if (c == '*') { width = va_arg(args, int); c = *++fmt; } else { while (isdigit(c)) { width = width * 10 + c - '0'; c = *++fmt; } } if (c == '.') { c = *++fmt; if (c == '*') { prec = va_arg(args, int); c = *++fmt; } else { while (isdigit(c)) { prec = prec * 10 + c - '0'; c = *++fmt; } } } str = 0; base = 0; neg = 0; ++fmt; switch (c) { case 'd': i = va_arg(args, int); if (i < 0) { neg = 1; val = -i; } else val = i; base = 10; break; case 'o': val = va_arg(args, unsigned int); base = 8; break; case 'x': val = va_arg(args, unsigned int); base = 16; break; case 'p': val = (unsigned long) va_arg(args, void *); base = 16; neg = 2; break; case 's': str = va_arg(args, char *); break; case 'c': num[0] = va_arg(args, int); num[1] = 0; str = num; break; case 'm': str = strerror(errno); break; case 'I': str = ip_ntoa(va_arg(args, u_int32_t)); break; case 't': time(&t); str = ctime(&t); str += 4; /* chop off the day name */ str[15] = 0; /* chop off year and newline */ break; case 'v': /* "visible" string */ case 'q': /* quoted string */ quoted = c == 'q'; p = va_arg(args, unsigned char *); if (fillch == '0' && prec > 0) { n = prec; } else { n = strlen((char *)p); if (prec > 0 && prec < n) n = prec; } while (n > 0 && buflen > 0) { c = *p++; --n; if (!quoted && c >= 0x80) { OUTCHAR('M'); OUTCHAR('-'); c -= 0x80; } if (quoted && (c == '"' || c == '\\')) OUTCHAR('\\'); if (c < 0x20 || (0x7f <= c && c < 0xa0)) { if (quoted) { OUTCHAR('\\'); switch (c) { case '\t': OUTCHAR('t'); break; case '\n': OUTCHAR('n'); break; case '\b': OUTCHAR('b'); break; case '\f': OUTCHAR('f'); break; default: OUTCHAR('x'); OUTCHAR(hexchars[c >> 4]); OUTCHAR(hexchars[c & 0xf]); } } else { if (c == '\t') OUTCHAR(c); else { OUTCHAR('^'); OUTCHAR(c ^ 0x40); } } } else OUTCHAR(c); } continue; default: *buf++ = '%'; if (c != '%') --fmt; /* so %z outputs %z etc. */ --buflen; continue; } if (base != 0) { str = num + sizeof(num); *--str = 0; while (str > num + neg) { *--str = hexchars[val % base]; val = val / base; if (--prec <= 0 && val == 0) break; } switch (neg) { case 1: *--str = '-'; break; case 2: *--str = 'x'; *--str = '0'; break; } len = num + sizeof(num) - 1 - str; } else { len = strlen(str); if (prec > 0 && len > prec) len = prec; } if (width > 0) { if (width > buflen) width = buflen; if ((n = width - len) > 0) { buflen -= n; for (; n > 0; --n) *buf++ = fillch; } } if (len > buflen) len = buflen; memcpy(buf, str, len); buf += len; buflen -= len; } *buf = 0; return buf - buf0; } /* * script_setenv - set an environment variable value to be used * for scripts that we run (e.g. ip-up, auth-up, etc.) */ void script_setenv(char *var, char *value) { int vl = strlen(var); int i; char *p, *newstring; if (asprintf(&newstring, "%s=%s", var, value) == -1) novm("script_setenv"); /* check if this variable is already set */ if (script_env != 0) { for (i = 0; (p = script_env[i]) != 0; ++i) { if (strncmp(p, var, vl) == 0 && p[vl] == '=') { free(p); script_env[i] = newstring; return; } } } else { i = 0; script_env = (char **) calloc(16, sizeof(char *)); if (script_env == 0) novm("script_setenv"); s_env_nalloc = 16; } /* reallocate script_env with more space if needed */ if (i + 1 >= s_env_nalloc) { int new_n = i + 17; char **newenv = reallocarray(script_env, new_n, sizeof(char *)); if (newenv == 0) novm("script_setenv"); script_env = newenv; s_env_nalloc = new_n; } script_env[i] = newstring; script_env[i+1] = 0; }