1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 char copyright[] = 10 "@(#) Copyright (c) 1990 The Regents of the University of California.\n\ 11 All rights reserved.\n"; 12 #endif /* not lint */ 13 14 #ifndef lint 15 static char sccsid[] = "@(#)sliplogin.c 5.6 (Berkeley) 03/02/91"; 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 <netinet/in.h> 62 #include <net/if.h> 63 #include <net/if_slvar.h> 64 65 #include <stdio.h> 66 #include <errno.h> 67 #include <ctype.h> 68 #include <string.h> 69 #include "pathnames.h" 70 71 int unit; 72 int slip_mode; 73 int speed; 74 int uid; 75 char loginargs[BUFSIZ]; 76 char loginfile[MAXPATHLEN]; 77 char loginname[BUFSIZ]; 78 79 struct slip_modes { 80 char *sm_name; 81 int sm_value; 82 } modes[] = { 83 "normal", 0, 84 "compress", SC_COMPRESS, 85 "noicmp", SC_NOICMP, 86 "autocomp", SC_AUTOCOMP 87 }; 88 89 void 90 findid(name) 91 char *name; 92 { 93 FILE *fp; 94 static char slopt[5][16]; 95 static char laddr[16]; 96 static char raddr[16]; 97 static char mask[16]; 98 char user[16]; 99 int i, j, n; 100 101 (void)strcpy(loginname, name); 102 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 103 (void)fprintf(stderr, "sliplogin: %s: %s\n", 104 _PATH_ACCESS, strerror(errno)); 105 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 106 exit(1); 107 } 108 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 109 if (ferror(fp)) 110 break; 111 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 112 user, laddr, raddr, mask, slopt[0], slopt[1], 113 slopt[2], slopt[3], slopt[4]); 114 if (user[0] == '#' || isspace(user[0])) 115 continue; 116 if (strcmp(user, name) != 0) 117 continue; 118 119 slip_mode = 0; 120 for (i = 0; i < n - 4; i++) { 121 for (j = 0; j < sizeof(modes)/sizeof(struct slip_modes); 122 j++) { 123 if (strcmp(modes[j].sm_name, slopt[i]) == 0) { 124 slip_mode |= modes[j].sm_value; 125 break; 126 } 127 } 128 } 129 130 /* 131 * we've found the guy we're looking for -- see if 132 * there's a login file we can use. First check for 133 * one specific to this host. If none found, try for 134 * a generic one. 135 */ 136 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 137 if (access(loginfile, R_OK|X_OK) != 0) { 138 (void)strcpy(loginfile, _PATH_LOGIN); 139 if (access(loginfile, R_OK|X_OK)) { 140 fputs("access denied - no login file\n", 141 stderr); 142 syslog(LOG_ERR, 143 "access denied for %s - no %s\n", 144 name, _PATH_LOGIN); 145 exit(5); 146 } 147 } 148 149 (void) fclose(fp); 150 return; 151 } 152 (void)fprintf(stderr, "SLIP access denied for %s\n", name); 153 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 154 exit(4); 155 /* NOTREACHED */ 156 } 157 158 char * 159 sigstr(s) 160 int s; 161 { 162 static char buf[32]; 163 164 switch (s) { 165 case SIGHUP: return("HUP"); 166 case SIGINT: return("INT"); 167 case SIGQUIT: return("QUIT"); 168 case SIGILL: return("ILL"); 169 case SIGTRAP: return("TRAP"); 170 case SIGIOT: return("IOT"); 171 case SIGEMT: return("EMT"); 172 case SIGFPE: return("FPE"); 173 case SIGKILL: return("KILL"); 174 case SIGBUS: return("BUS"); 175 case SIGSEGV: return("SEGV"); 176 case SIGSYS: return("SYS"); 177 case SIGPIPE: return("PIPE"); 178 case SIGALRM: return("ALRM"); 179 case SIGTERM: return("TERM"); 180 case SIGURG: return("URG"); 181 case SIGSTOP: return("STOP"); 182 case SIGTSTP: return("TSTP"); 183 case SIGCONT: return("CONT"); 184 case SIGCHLD: return("CHLD"); 185 case SIGTTIN: return("TTIN"); 186 case SIGTTOU: return("TTOU"); 187 case SIGIO: return("IO"); 188 case SIGXCPU: return("XCPU"); 189 case SIGXFSZ: return("XFSZ"); 190 case SIGVTALRM: return("VTALRM"); 191 case SIGPROF: return("PROF"); 192 case SIGWINCH: return("WINCH"); 193 #ifdef SIGLOST 194 case SIGLOST: return("LOST"); 195 #endif 196 case SIGUSR1: return("USR1"); 197 case SIGUSR2: return("USR2"); 198 } 199 (void)sprintf(buf, "sig %d", s); 200 return(buf); 201 } 202 203 void 204 hup_handler(s) 205 int s; 206 { 207 char logoutfile[MAXPATHLEN]; 208 209 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname); 210 if (access(logoutfile, R_OK|X_OK) != 0) 211 (void)strcpy(logoutfile, _PATH_LOGOUT); 212 if (access(logoutfile, R_OK|X_OK) == 0) { 213 char logincmd[2*MAXPATHLEN+32]; 214 215 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 216 loginargs); 217 (void) system(logincmd); 218 } 219 (void) close(0); 220 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 221 sigstr(s)); 222 exit(1); 223 /* NOTREACHED */ 224 } 225 226 main(argc, argv) 227 int argc; 228 char *argv[]; 229 { 230 int fd, s, ldisc, odisc; 231 char *name; 232 #ifdef POSIX 233 struct termios tios, otios; 234 #else 235 struct sgttyb tty, otty; 236 #endif 237 char logincmd[2*BUFSIZ+32]; 238 extern uid_t getuid(); 239 240 if ((name = strrchr(argv[0], '/')) == NULL) 241 name = argv[0]; 242 s = getdtablesize(); 243 for (fd = 3 ; fd < s ; fd++) 244 (void) close(fd); 245 openlog(name, LOG_PID, LOG_DAEMON); 246 uid = getuid(); 247 if (argc > 1) { 248 findid(argv[1]); 249 250 /* 251 * Disassociate from current controlling terminal, if any, 252 * and ensure that the slip line is our controlling terminal. 253 */ 254 #ifdef POSIX 255 if (fork() > 0) 256 exit(0); 257 if (setsid() != 0) 258 perror("setsid"); 259 #else 260 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 261 extern char *ttyname(); 262 263 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 264 (void) close(fd); 265 /* open slip tty again to acquire as controlling tty? */ 266 fd = open(ttyname(0), O_RDWR, 0); 267 if (fd >= 0) 268 (void) close(fd); 269 } 270 (void) setpgrp(0, getpid()); 271 #endif 272 if (argc > 2) { 273 if ((fd = open(argv[2], O_RDWR)) == -1) { 274 perror(argv[2]); 275 exit(2); 276 } 277 (void) dup2(fd, 0); 278 if (fd > 2) 279 close(fd); 280 } 281 #ifdef TIOCSCTTY 282 if (ioctl(0, TIOCSCTTY, (caddr_t)0) != 0) 283 perror("ioctl (TIOCSCTTY)"); 284 #endif 285 } else { 286 extern char *getlogin(); 287 288 if ((name = getlogin()) == NULL) { 289 (void) fprintf(stderr, "access denied - no username\n"); 290 syslog(LOG_ERR, "access denied - getlogin returned 0\n"); 291 exit(1); 292 } 293 findid(name); 294 } 295 (void) fchmod(0, 0600); 296 (void) fprintf(stderr, "starting slip login for %s\n", loginname); 297 #ifdef POSIX 298 /* set up the line parameters */ 299 if (tcgetattr(0, &tios) < 0) { 300 syslog(LOG_ERR, "tcgetattr: %m"); 301 exit(1); 302 } 303 otios = tios; 304 cfmakeraw(&tios); 305 tios.c_iflag &= ~IMAXBEL; 306 if (tcsetattr(0, TCSAFLUSH, &tios) < 0) { 307 syslog(LOG_ERR, "tcsetattr: %m"); 308 exit(1); 309 } 310 speed = cfgetispeed(&tios); 311 #else 312 /* set up the line parameters */ 313 if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) { 314 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 315 exit(1); 316 } 317 otty = tty; 318 speed = tty.sg_ispeed; 319 tty.sg_flags = RAW | ANYP; 320 if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) { 321 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 322 exit(1); 323 } 324 #endif 325 /* find out what ldisc we started with */ 326 if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) { 327 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 328 exit(1); 329 } 330 ldisc = SLIPDISC; 331 if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) { 332 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 333 exit(1); 334 } 335 /* find out what unit number we were assigned */ 336 if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) { 337 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 338 exit(1); 339 } 340 (void) signal(SIGHUP, hup_handler); 341 (void) signal(SIGTERM, hup_handler); 342 343 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 344 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 345 loginargs); 346 /* 347 * aim stdout and errout at /dev/null so logincmd output won't 348 * babble into the slip tty line. 349 */ 350 (void) close(1); 351 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 352 if (fd < 0) { 353 syslog(LOG_ERR, "open /dev/null: %m"); 354 exit(1); 355 } 356 (void) dup2(fd, 1); 357 (void) close(fd); 358 } 359 (void) dup2(1, 2); 360 361 /* 362 * Run login and logout scripts as root (real and effective); 363 * current route(8) is setuid root, and checks the real uid 364 * to see whether changes are allowed (or just "route get"). 365 */ 366 (void) setuid(0); 367 if (s = system(logincmd)) { 368 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 369 loginname, s, loginfile); 370 (void) ioctl(0, TIOCSETD, (caddr_t)&odisc); 371 exit(6); 372 } 373 if (ioctl(0, SLIOCSFLAGS, (caddr_t)&slip_mode) < 0) { 374 syslog(LOG_ERR, "ioctl (SLIOCSFLAGS): %m"); 375 exit(1); 376 } 377 378 /* twiddle thumbs until we get a signal */ 379 while (1) 380 sigpause(0); 381 382 /* NOTREACHED */ 383 } 384