/*- * Copyright (c) 1990, 1993 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#) Copyright (c) 1990, 1993 The Regents of the University of California. All rights reserved. * @(#)sliplogin.c 8.2 (Berkeley) 2/1/94 * $FreeBSD: src/usr.sbin/sliplogin/sliplogin.c,v 1.9.6.2 2001/07/19 05:21:28 kris Exp $ */ /* * sliplogin.c * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!] * * This program initializes its own tty port to be an async TCP/IP interface. * It sets the line discipline to slip, invokes a shell script to initialize * the network interface, then pauses forever waiting for hangup. * * It is a remote descendant of several similar programs with incestuous ties: * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL. * - slattach, probably by Rick Adams but touched by countless hordes. * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it. * * There are two forms of usage: * * "sliplogin" * Invoked simply as "sliplogin", the program looks up the username * in the file /etc/slip.hosts. * If an entry is found, the line on fd0 is configured for SLIP operation * as specified in the file. * * "sliplogin IPhostlogin #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pathnames.h" extern char **environ; static char *restricted_environ[] = { "PATH=" _PATH_STDPATH, NULL }; static int unit; static int slip_mode; static speed_t speed; static int uid; static int keepal; static int outfill; static int slunit; static char loginargs[BUFSIZ]; static char loginfile[MAXPATHLEN]; static char loginname[BUFSIZ]; static char raddr[32]; /* remote address */ static char ifname[IFNAMSIZ]; /* interface name */ static char pidfilename[MAXPATHLEN]; /* name of pid file */ static char iffilename[MAXPATHLEN]; /* name of if file */ static pid_t pid; /* our pid */ static char * make_ipaddr(void) { static char address[20] =""; struct hostent *he; unsigned long ipaddr; address[0] = '\0'; if ((he = gethostbyname(raddr)) != NULL) { ipaddr = ntohl(*(long *)he->h_addr_list[0]); sprintf(address, "%hu.%hu.%hu.%hu", (ushort)(ipaddr >> 24), (ushort)((ipaddr & 0x00ff0000) >> 16), (ushort)((ipaddr & 0x0000ff00) >> 8), (ushort)((ipaddr & 0x000000ff))); } return address; } static struct slip_modes { const char *sm_name; int sm_or_flag; int sm_and_flag; } modes[] = { { "normal", 0, 0 }, { "compress", IFF_LINK0, IFF_LINK2 }, { "noicmp", IFF_LINK1, 0 }, { "autocomp", IFF_LINK2, IFF_LINK0 } }; static void findid(char *name) { FILE *fp; static char slopt[5][16]; static char laddr[16]; static char mask[16]; char slparmsfile[MAXPATHLEN]; char user[16]; char buf[128]; int i, j, n; environ = restricted_environ; /* minimal protection for system() */ strncpy(loginname, name, sizeof(loginname)-1); loginname[sizeof(loginname)-1] = '\0'; if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { accfile_err: syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); exit(1); } while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { if (ferror(fp)) goto accfile_err; if (loginargs[0] == '#' || isspace(loginargs[0])) continue; n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", user, laddr, raddr, mask, slopt[0], slopt[1], slopt[2], slopt[3], slopt[4]); if (n < 4) { syslog(LOG_ERR, "%s: wrong format\n", _PATH_ACCESS); exit(1); } if (strcmp(user, name) != 0) continue; fclose(fp); slip_mode = 0; for (i = 0; i < n - 4; i++) { for (j = 0; j < (int)NELEM(modes); j++) { if (strcmp(modes[j].sm_name, slopt[i]) == 0) { slip_mode |= (modes[j].sm_or_flag); slip_mode &= ~(modes[j].sm_and_flag); break; } } } /* * we've found the guy we're looking for -- see if * there's a login file we can use. First check for * one specific to this host. If none found, try for * a generic one. */ snprintf(loginfile, sizeof(loginfile), "%s.%s", _PATH_SLOGIN, name); if (access(loginfile, R_OK|X_OK) != 0) { strncpy(loginfile, _PATH_SLOGIN, sizeof(loginfile)-1); loginfile[sizeof(loginfile)-1] = '\0'; if (access(loginfile, R_OK|X_OK)) { syslog(LOG_ERR, "access denied for %s - no %s\n", name, _PATH_SLOGIN); exit(5); } } snprintf(slparmsfile, sizeof(slparmsfile), "%s.%s", _PATH_SLPARMS, name); if (access(slparmsfile, R_OK|X_OK) != 0) { strncpy(slparmsfile, _PATH_SLPARMS, sizeof(slparmsfile)-1); slparmsfile[sizeof(slparmsfile)-1] = '\0'; if (access(slparmsfile, R_OK|X_OK)) *slparmsfile = '\0'; } keepal = outfill = 0; slunit = -1; if (*slparmsfile) { if ((fp = fopen(slparmsfile, "r")) == NULL) { slfile_err: syslog(LOG_ERR, "%s: %m\n", slparmsfile); exit(1); } n = 0; while (fgets(buf, sizeof(buf) - 1, fp) != NULL) { if (ferror(fp)) goto slfile_err; if (buf[0] == '#' || isspace(buf[0])) continue; n = sscanf(buf, "%d %d %d", &keepal, &outfill, &slunit); if (n < 1) { slwrong_fmt: syslog(LOG_ERR, "%s: wrong format\n", slparmsfile); exit(1); } fclose(fp); break; } if (n == 0) goto slwrong_fmt; } return; } syslog(LOG_ERR, "SLIP access denied for %s\n", name); exit(4); /* NOTREACHED */ } static const char * sigstr(int s) { static char buf[32]; switch (s) { case SIGHUP: return("HUP"); case SIGINT: return("INT"); case SIGQUIT: return("QUIT"); case SIGILL: return("ILL"); case SIGTRAP: return("TRAP"); case SIGIOT: return("IOT"); case SIGEMT: return("EMT"); case SIGFPE: return("FPE"); case SIGKILL: return("KILL"); case SIGBUS: return("BUS"); case SIGSEGV: return("SEGV"); case SIGSYS: return("SYS"); case SIGPIPE: return("PIPE"); case SIGALRM: return("ALRM"); case SIGTERM: return("TERM"); case SIGURG: return("URG"); case SIGSTOP: return("STOP"); case SIGTSTP: return("TSTP"); case SIGCONT: return("CONT"); case SIGCHLD: return("CHLD"); case SIGTTIN: return("TTIN"); case SIGTTOU: return("TTOU"); case SIGIO: return("IO"); case SIGXCPU: return("XCPU"); case SIGXFSZ: return("XFSZ"); case SIGVTALRM: return("VTALRM"); case SIGPROF: return("PROF"); case SIGWINCH: return("WINCH"); #ifdef SIGLOST case SIGLOST: return("LOST"); #endif case SIGUSR1: return("USR1"); case SIGUSR2: return("USR2"); } snprintf(buf, sizeof(buf), "sig %d", s); return(buf); } static void hup_handler(int s) { char logoutfile[MAXPATHLEN]; close(0); seteuid(0); snprintf(logoutfile, sizeof(logoutfile), "%s.%.990s", _PATH_SLOGOUT, loginname); if (access(logoutfile, R_OK|X_OK) != 0) { strncpy(logoutfile, _PATH_SLOGOUT, sizeof(logoutfile)-1); logoutfile[sizeof(logoutfile)-1] = '\0'; } if (access(logoutfile, R_OK|X_OK) == 0) { char logincmd[2*MAXPATHLEN+32]; snprintf(logincmd, sizeof(logincmd), "%s %d %u %s", logoutfile, unit, speed, loginargs); system(logincmd); } syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, sigstr(s)); if (unlink(pidfilename) < 0 && errno != ENOENT) syslog(LOG_WARNING, "unable to delete pid file: %m"); if (unlink(iffilename) < 0 && errno != ENOENT) syslog(LOG_WARNING, "unable to delete if file: %m"); exit(1); /* NOTREACHED */ } /* Modify the slip line mode and add any compression or no-icmp flags. */ static void line_flags(int _unit) { struct ifreq ifr; int s; /* open a socket as the handle to the interface */ s = socket(AF_INET, SOCK_DGRAM, 0); if (s < 0) { syslog(LOG_ERR, "socket: %m"); exit(1); } sprintf(ifr.ifr_name, "sl%d", _unit); /* get the flags for the interface */ if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) { syslog(LOG_ERR, "ioctl (SIOCGIFFLAGS): %m"); exit(1); } /* Assert any compression or no-icmp flags. */ #define SLMASK (~(IFF_LINK0 | IFF_LINK1 | IFF_LINK2)) ifr.ifr_flags &= SLMASK; ifr.ifr_flags |= slip_mode; if (ioctl(s, SIOCSIFFLAGS, (caddr_t)&ifr) < 0) { syslog(LOG_ERR, "ioctl (SIOCSIFFLAGS): %m"); exit(1); } close(s); } int main(int argc, char *argv[]) { int fd, s, ldisc; char *name; struct termios tios; char logincmd[2*BUFSIZ+32]; FILE *pidfile; /* pid file */ FILE *iffile; /* interfaces file */ char *p; int n; char devnam[MAXPATHLEN] = _PATH_TTY; /* Device name */ if ((name = strrchr(argv[0], '/')) == NULL) name = argv[0]; s = getdtablesize(); for (fd = 3 ; fd < s ; fd++) close(fd); openlog(name, LOG_PID|LOG_PERROR, LOG_DAEMON); uid = getuid(); if (argc > 1) { findid(argv[1]); /* * Disassociate from current controlling terminal, if any, * and ensure that the slip line is our controlling terminal. */ if (daemon(1, 1)) { syslog(LOG_ERR, "daemon(1, 1): %m"); exit(1); } if (argc > 2) { if ((fd = open(argv[2], O_RDWR)) == -1) { syslog(LOG_ERR, "open %s: %m", argv[2]); exit(2); } dup2(fd, 0); if (fd > 2) close(fd); } if (ioctl(0, TIOCSCTTY, 0) == -1) { syslog(LOG_ERR, "ioctl (TIOCSCTTY): %m"); exit(1); } if (tcsetpgrp(0, getpid()) < 0) { syslog(LOG_ERR, "tcsetpgrp failed: %m"); exit(1); } } else { if ((name = getlogin()) == NULL) { syslog(LOG_ERR, "access denied - login name not found\n"); exit(1); } findid(name); } fchmod(0, 0600); fprintf(stderr, "starting slip login for %s\n", loginname); fprintf(stderr, "your address is %s\n\n", make_ipaddr()); fflush(stderr); sleep(1); /* set up the line parameters */ if (tcgetattr(0, &tios) < 0) { syslog(LOG_ERR, "tcgetattr: %m"); exit(1); } cfmakeraw(&tios); if (tcsetattr(0, TCSAFLUSH, &tios) < 0) { syslog(LOG_ERR, "tcsetattr: %m"); exit(1); } speed = cfgetispeed(&tios); ldisc = SLIPDISC; if (ioctl(0, TIOCSETD, &ldisc) < 0) { syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); exit(1); } if (slunit >= 0 && ioctl(0, SLIOCSUNIT, &slunit) < 0) { syslog(LOG_ERR, "ioctl (SLIOCSUNIT): %m"); exit(1); } /* find out what unit number we were assigned */ if (ioctl(0, SLIOCGUNIT, &unit) < 0) { syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); exit(1); } signal(SIGHUP, hup_handler); signal(SIGTERM, hup_handler); if (keepal > 0) { signal(SIGURG, hup_handler); if (ioctl(0, SLIOCSKEEPAL, &keepal) < 0) { syslog(LOG_ERR, "ioctl(SLIOCSKEEPAL): %m"); exit(1); } } if (outfill > 0 && ioctl(0, SLIOCSOUTFILL, &outfill) < 0) { syslog(LOG_ERR, "ioctl(SLIOCSOUTFILL): %m"); exit(1); } /* write pid to file */ pid = getpid(); sprintf(ifname, "sl%d", unit); sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname); if ((pidfile = fopen(pidfilename, "w")) != NULL) { fprintf(pidfile, "%d\n", pid); fclose(pidfile); } else { syslog(LOG_ERR, "Failed to create pid file %s: %m", pidfilename); pidfilename[0] = 0; } /* write interface unit number to file */ p = ttyname(0); if (p) strcpy(devnam, p); for (n = strlen(devnam); n > 0; n--) if (devnam[n] == '/') { n++; break; } sprintf(iffilename, "%s%s.if", _PATH_VARRUN, &devnam[n]); if ((iffile = fopen(iffilename, "w")) != NULL) { fprintf(iffile, "sl%d\n", unit); fclose(iffile); } else { syslog(LOG_ERR, "Failed to create if file %s: %m", iffilename); iffilename[0] = 0; } syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); snprintf(logincmd, sizeof(logincmd), "%s %d %u %s", loginfile, unit, speed, loginargs); /* * aim stdout and errout at /dev/null so logincmd output won't * babble into the slip tty line. */ close(1); if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { if (fd < 0) { syslog(LOG_ERR, "open %s: %m", _PATH_DEVNULL); exit(1); } dup2(fd, 1); close(fd); } dup2(1, 2); /* * Run login and logout scripts as root (real and effective); * current route(8) is setuid root, and checks the real uid * to see whether changes are allowed (or just "route get"). */ setuid(0); if ((s = system(logincmd)) == -1) { syslog(LOG_ERR, "%s login failed: exit status %d from %s", loginname, s, loginfile); exit(6); } /* Handle any compression or no-icmp flags. */ line_flags(unit); /* reset uid to users' to allow the user to give a signal. */ seteuid(uid); /* twiddle thumbs until we get a signal */ while (1) sigpause(0); /* NOTREACHED */ }