1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 static char copyright[] = 10 "@(#) Copyright (c) 1990, 1993\n\ 11 The Regents of the University of California. All rights reserved.\n"; 12 #endif /* not lint */ 13 14 #ifndef lint 15 static char sccsid[] = "@(#)sliplogin.c 8.2 (Berkeley) 02/01/94"; 16 #endif /* not lint */ 17 18 /* 19 * sliplogin.c 20 * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!] 21 * 22 * This program initializes its own tty port to be an async TCP/IP interface. 23 * It sets the line discipline to slip, invokes a shell script to initialize 24 * the network interface, then pauses forever waiting for hangup. 25 * 26 * It is a remote descendant of several similar programs with incestuous ties: 27 * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL. 28 * - slattach, probably by Rick Adams but touched by countless hordes. 29 * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it. 30 * 31 * There are two forms of usage: 32 * 33 * "sliplogin" 34 * Invoked simply as "sliplogin", the program looks up the username 35 * in the file /etc/slip.hosts. 36 * If an entry is found, the line on fd0 is configured for SLIP operation 37 * as specified in the file. 38 * 39 * "sliplogin IPhostlogin </dev/ttyb" 40 * Invoked by root with a username, the name is looked up in the 41 * /etc/slip.hosts file and if found fd0 is configured as in case 1. 42 */ 43 44 #include <sys/param.h> 45 #include <sys/socket.h> 46 #include <sys/signal.h> 47 #include <sys/file.h> 48 #include <sys/syslog.h> 49 #include <netdb.h> 50 51 #if BSD >= 199006 52 #define POSIX 53 #endif 54 #ifdef POSIX 55 #include <sys/termios.h> 56 #include <sys/ioctl.h> 57 #include <ttyent.h> 58 #else 59 #include <sgtty.h> 60 #endif 61 #include <net/slip.h> 62 63 #include <stdio.h> 64 #include <errno.h> 65 #include <ctype.h> 66 #include <string.h> 67 #include "pathnames.h" 68 69 int unit; 70 int speed; 71 int uid; 72 char loginargs[BUFSIZ]; 73 char loginfile[MAXPATHLEN]; 74 char loginname[BUFSIZ]; 75 76 void 77 findid(name) 78 char *name; 79 { 80 FILE *fp; 81 static char slopt[5][16]; 82 static char laddr[16]; 83 static char raddr[16]; 84 static char mask[16]; 85 char user[16]; 86 int i, j, n; 87 88 (void)strcpy(loginname, name); 89 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 90 (void)fprintf(stderr, "sliplogin: %s: %s\n", 91 _PATH_ACCESS, strerror(errno)); 92 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 93 exit(1); 94 } 95 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 96 if (ferror(fp)) 97 break; 98 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 99 user, laddr, raddr, mask, slopt[0], slopt[1], 100 slopt[2], slopt[3], slopt[4]); 101 if (user[0] == '#' || isspace(user[0])) 102 continue; 103 if (strcmp(user, name) != 0) 104 continue; 105 106 /* 107 * we've found the guy we're looking for -- see if 108 * there's a login file we can use. First check for 109 * one specific to this host. If none found, try for 110 * a generic one. 111 */ 112 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 113 if (access(loginfile, R_OK|X_OK) != 0) { 114 (void)strcpy(loginfile, _PATH_LOGIN); 115 if (access(loginfile, R_OK|X_OK)) { 116 fputs("access denied - no login file\n", 117 stderr); 118 syslog(LOG_ERR, 119 "access denied for %s - no %s\n", 120 name, _PATH_LOGIN); 121 exit(5); 122 } 123 } 124 125 (void) fclose(fp); 126 return; 127 } 128 (void)fprintf(stderr, "SLIP access denied for %s\n", name); 129 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 130 exit(4); 131 /* NOTREACHED */ 132 } 133 134 char * 135 sigstr(s) 136 int s; 137 { 138 static char buf[32]; 139 140 switch (s) { 141 case SIGHUP: return("HUP"); 142 case SIGINT: return("INT"); 143 case SIGQUIT: return("QUIT"); 144 case SIGILL: return("ILL"); 145 case SIGTRAP: return("TRAP"); 146 case SIGIOT: return("IOT"); 147 case SIGEMT: return("EMT"); 148 case SIGFPE: return("FPE"); 149 case SIGKILL: return("KILL"); 150 case SIGBUS: return("BUS"); 151 case SIGSEGV: return("SEGV"); 152 case SIGSYS: return("SYS"); 153 case SIGPIPE: return("PIPE"); 154 case SIGALRM: return("ALRM"); 155 case SIGTERM: return("TERM"); 156 case SIGURG: return("URG"); 157 case SIGSTOP: return("STOP"); 158 case SIGTSTP: return("TSTP"); 159 case SIGCONT: return("CONT"); 160 case SIGCHLD: return("CHLD"); 161 case SIGTTIN: return("TTIN"); 162 case SIGTTOU: return("TTOU"); 163 case SIGIO: return("IO"); 164 case SIGXCPU: return("XCPU"); 165 case SIGXFSZ: return("XFSZ"); 166 case SIGVTALRM: return("VTALRM"); 167 case SIGPROF: return("PROF"); 168 case SIGWINCH: return("WINCH"); 169 #ifdef SIGLOST 170 case SIGLOST: return("LOST"); 171 #endif 172 case SIGUSR1: return("USR1"); 173 case SIGUSR2: return("USR2"); 174 } 175 (void)sprintf(buf, "sig %d", s); 176 return(buf); 177 } 178 179 void 180 hup_handler(s) 181 int s; 182 { 183 char logoutfile[MAXPATHLEN]; 184 185 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname); 186 if (access(logoutfile, R_OK|X_OK) != 0) 187 (void)strcpy(logoutfile, _PATH_LOGOUT); 188 if (access(logoutfile, R_OK|X_OK) == 0) { 189 char logincmd[2*MAXPATHLEN+32]; 190 191 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 192 loginargs); 193 (void) system(logincmd); 194 } 195 (void) close(0); 196 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 197 sigstr(s)); 198 exit(1); 199 /* NOTREACHED */ 200 } 201 202 main(argc, argv) 203 int argc; 204 char *argv[]; 205 { 206 int fd, s, ldisc, odisc; 207 char *name; 208 #ifdef POSIX 209 struct termios tios, otios; 210 #else 211 struct sgttyb tty, otty; 212 #endif 213 char logincmd[2*BUFSIZ+32]; 214 extern uid_t getuid(); 215 216 if ((name = strrchr(argv[0], '/')) == NULL) 217 name = argv[0]; 218 s = getdtablesize(); 219 for (fd = 3 ; fd < s ; fd++) 220 (void) close(fd); 221 openlog(name, LOG_PID, LOG_DAEMON); 222 uid = getuid(); 223 if (argc > 1) { 224 findid(argv[1]); 225 226 /* 227 * Disassociate from current controlling terminal, if any, 228 * and ensure that the slip line is our controlling terminal. 229 */ 230 #ifdef POSIX 231 if (fork() > 0) 232 exit(0); 233 if (setsid() != 0) 234 perror("setsid"); 235 #else 236 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 237 extern char *ttyname(); 238 239 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 240 (void) close(fd); 241 /* open slip tty again to acquire as controlling tty? */ 242 fd = open(ttyname(0), O_RDWR, 0); 243 if (fd >= 0) 244 (void) close(fd); 245 } 246 (void) setpgrp(0, getpid()); 247 #endif 248 if (argc > 2) { 249 if ((fd = open(argv[2], O_RDWR)) == -1) { 250 perror(argv[2]); 251 exit(2); 252 } 253 (void) dup2(fd, 0); 254 if (fd > 2) 255 close(fd); 256 } 257 #ifdef TIOCSCTTY 258 if (ioctl(0, TIOCSCTTY, (caddr_t)0) != 0) 259 perror("ioctl (TIOCSCTTY)"); 260 #endif 261 } else { 262 extern char *getlogin(); 263 264 if ((name = getlogin()) == NULL) { 265 (void) fprintf(stderr, "access denied - no username\n"); 266 syslog(LOG_ERR, "access denied - getlogin returned 0\n"); 267 exit(1); 268 } 269 findid(name); 270 } 271 (void) fchmod(0, 0600); 272 (void) fprintf(stderr, "starting slip login for %s\n", loginname); 273 #ifdef POSIX 274 /* set up the line parameters */ 275 if (tcgetattr(0, &tios) < 0) { 276 syslog(LOG_ERR, "tcgetattr: %m"); 277 exit(1); 278 } 279 otios = tios; 280 cfmakeraw(&tios); 281 tios.c_iflag &= ~IMAXBEL; 282 if (tcsetattr(0, TCSAFLUSH, &tios) < 0) { 283 syslog(LOG_ERR, "tcsetattr: %m"); 284 exit(1); 285 } 286 speed = cfgetispeed(&tios); 287 #else 288 /* set up the line parameters */ 289 if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) { 290 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 291 exit(1); 292 } 293 otty = tty; 294 speed = tty.sg_ispeed; 295 tty.sg_flags = RAW | ANYP; 296 if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) { 297 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 298 exit(1); 299 } 300 #endif 301 /* find out what ldisc we started with */ 302 if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) { 303 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 304 exit(1); 305 } 306 ldisc = SLIPDISC; 307 if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) { 308 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 309 exit(1); 310 } 311 /* find out what unit number we were assigned */ 312 if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) { 313 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 314 exit(1); 315 } 316 (void) signal(SIGHUP, hup_handler); 317 (void) signal(SIGTERM, hup_handler); 318 319 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 320 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 321 loginargs); 322 /* 323 * aim stdout and errout at /dev/null so logincmd output won't 324 * babble into the slip tty line. 325 */ 326 (void) close(1); 327 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 328 if (fd < 0) { 329 syslog(LOG_ERR, "open /dev/null: %m"); 330 exit(1); 331 } 332 (void) dup2(fd, 1); 333 (void) close(fd); 334 } 335 (void) dup2(1, 2); 336 337 /* 338 * Run login and logout scripts as root (real and effective); 339 * current route(8) is setuid root, and checks the real uid 340 * to see whether changes are allowed (or just "route get"). 341 */ 342 (void) setuid(0); 343 if (s = system(logincmd)) { 344 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 345 loginname, s, loginfile); 346 (void) ioctl(0, TIOCSETD, (caddr_t)&odisc); 347 exit(6); 348 } 349 350 /* twiddle thumbs until we get a signal */ 351 while (1) 352 sigpause(0); 353 354 /* NOTREACHED */ 355 } 356