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 5.3 (Berkeley) 07/01/90"; 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" and a realuid != 0, the program looks up 35 * the uid in /etc/passwd, and then the username in the file /etc/hosts.slip. 36 * If and entry is found, the line on fd0 is configured for SLIP operation 37 * as specified in the file. 38 * 39 * "sliplogin IPhost1 </dev/ttyb" 40 * Invoked by root with a username, the name is looked up in the 41 * /etc/hosts.slip 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/ioctl.h> 47 #include <sys/signal.h> 48 #include <sys/file.h> 49 #include <sys/syslog.h> 50 #include <netdb.h> 51 52 #if defined(BSD4_4) 53 #define TERMIOS 54 #endif 55 #ifdef TERMIOS 56 #include <sys/termios.h> 57 #include <ttyent.h> 58 #endif 59 #include <netinet/in.h> 60 #include <net/if.h> 61 #include <net/if_slvar.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 slip_mode; 71 int speed; 72 char loginargs[BUFSIZ]; 73 char loginfile[BUFSIZ]; 74 char logoutfile[BUFSIZ]; 75 char loginname[BUFSIZ]; 76 77 struct slip_modes { 78 char *sm_name; 79 int sm_value; 80 } modes[] = { 81 "normal", 0, 82 "compress", SC_COMPRESS, 83 "noicmp", SC_NOICMP, 84 "autocomp", SC_AUTOCOMP 85 }; 86 87 void 88 findid(name) 89 char *name; 90 { 91 FILE *fp; 92 static char slopt[5][16]; 93 static char laddr[16]; 94 static char raddr[16]; 95 static char mask[16]; 96 char user[16]; 97 int i, j, n; 98 99 (void)strcpy(loginname, name); 100 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 101 (void)fprintf(stderr, "sliplogin: %s: %s\n", 102 _PATH_ACCESS, strerror(errno)); 103 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 104 exit(1); 105 } 106 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 107 if (ferror(fp)) 108 break; 109 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 110 user, laddr, raddr, mask, slopt[0], slopt[1], 111 slopt[2], slopt[3], slopt[4]); 112 if (user[0] == '#' || isspace(user[0])) 113 continue; 114 if (strcmp(user, name) != 0) 115 continue; 116 117 slip_mode = 0; 118 for (i = 0; i < n - 4; i++) { 119 for (j = 0; j < sizeof(modes)/sizeof(struct slip_modes); 120 j++) { 121 if (strcmp(modes[j].sm_name, slopt[i]) == 0) { 122 slip_mode |= modes[j].sm_value; 123 break; 124 } 125 } 126 } 127 128 /* 129 * we've found the guy we're looking for -- see if 130 * there's a login file we can use. First check for 131 * one specific to this host. If none found, try for 132 * a generic one. 133 */ 134 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 135 if (access(loginfile, R_OK|X_OK)) { 136 (void)strcpy(loginfile, _PATH_LOGIN); 137 (void)strcpy(logoutfile, _PATH_LOGOUT); 138 if (access(loginfile, R_OK|X_OK)) { 139 fputs("access denied - no login file\n", 140 stderr); 141 syslog(LOG_ERR, 142 "access denied for %s - no %s\n", 143 name, _PATH_LOGIN); 144 exit(5); 145 } 146 } else 147 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, name); 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 int 204 hup_handler(s) 205 int s; 206 { 207 if (access(logoutfile, R_OK|X_OK) == 0) { 208 char logincmd[2*BUFSIZ+32]; 209 210 (void)sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 211 loginargs); 212 (void)system(logincmd); 213 } 214 (void)close(0); 215 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 216 sigstr(s)); 217 exit(1); 218 /* NOTREACHED */ 219 } 220 221 main(argc, argv) 222 int argc; 223 char *argv[]; 224 { 225 int fd, s, ldisc, odisc; 226 char *name; 227 #ifdef TERMIOS 228 struct termios tios, otios; 229 #else 230 struct sgttyb tty, otty; 231 #endif 232 char logincmd[2*BUFSIZ+32]; 233 extern uid_t getuid(); 234 235 if ((name = strrchr(argv[0], '/')) == NULL) 236 name = argv[0]; 237 s = getdtablesize(); 238 for (fd = 3 ; fd < s ; fd++) 239 (void) close(fd); 240 openlog(name, LOG_PID, LOG_DAEMON); 241 if (argc > 1) { 242 if (argc > 2) { 243 (void)fprintf(stderr, "Usage: %s loginname\n", argv[0]); 244 exit(1); 245 } 246 findid(argv[1]); 247 248 /* 249 * Disassociate from current controlling terminal, if any, 250 * and ensure that the slip line is our controlling terminal. 251 */ 252 #ifdef TERMIOS 253 (void) setsid(); 254 (void) ioctl(0, TIOCSCTTY, (caddr_t)0); 255 #else 256 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 257 extern char *ttyname(); 258 259 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 260 (void) close(fd); 261 /* open slip tty again to acquire as controlling tty? */ 262 fd = open(ttyname(0), O_RDWR, 0); 263 if (fd >= 0) 264 (void) close(fd); 265 } 266 (void) setpgrp(0, getpid()); 267 #endif 268 } else { 269 extern char *getenv(); 270 271 if ((name = getenv("USER")) == NULL) { 272 (void) fprintf(stderr, "access denied - no username\n"); 273 syslog(LOG_ERR, "access denied - no username\n"); 274 exit(1); 275 } 276 findid(name); 277 } 278 (void) fchmod(0, 0600); 279 (void) fprintf(stderr, "starting slip login for %s\n", loginname); 280 #ifdef TERMIOS 281 /* set up the line parameters */ 282 if (ioctl(0, TIOCGETA, (caddr_t)&tios) < 0) { 283 syslog(LOG_ERR, "ioctl (TIOCGETA): %m"); 284 exit(1); 285 } 286 otios = tios; 287 tios.c_cflag = CS8|CREAD|HUPCL; 288 tios.c_iflag = IGNBRK; 289 tios.c_oflag = tios.c_lflag = 0; 290 if (ioctl(0, TIOCSETA, (caddr_t)&tios) < 0) { 291 syslog(LOG_ERR, "ioctl (TIOCSETA) (1): %m"); 292 exit(1); 293 } 294 #else 295 /* set up the line parameters */ 296 if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) { 297 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 298 exit(1); 299 } 300 otty = tty; 301 speed = tty.sg_ispeed; 302 tty.sg_flags = RAW | ANYP; 303 if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) { 304 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 305 exit(1); 306 } 307 #endif 308 /* find out what ldisc we started with */ 309 if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) { 310 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 311 exit(1); 312 } 313 ldisc = SLIPDISC; 314 if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) { 315 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 316 exit(1); 317 } 318 /* find out what unit number we were assigned */ 319 if (ioctl(0, TIOCGETD, (caddr_t)&unit) < 0) { 320 syslog(LOG_ERR, "ioctl (TIOCGETD) (2): %m"); 321 exit(1); 322 } 323 (void) signal(SIGHUP, hup_handler); 324 (void) signal(SIGTERM, hup_handler); 325 326 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 327 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 328 loginargs); 329 /* 330 * aim stdout and errout at /dev/null so logincmd output won't 331 * babble into the slip tty line. 332 */ 333 (void)close(1); 334 if ((fd = open("/dev/null", O_WRONLY, 0)) != 1) { 335 if (fd < 0) { 336 syslog(LOG_ERR, "open /dev/null: %m"); 337 exit(1); 338 } 339 (void)dup2(fd, 1); 340 (void)close(fd); 341 } 342 (void)dup2(1,2); 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 if (ioctl(0, SLIOCSFLAGS, (caddr_t)&slip_mode) < 0) { 350 syslog(LOG_ERR, "ioctl (SLIOCSFLAGS): %m"); 351 exit(1); 352 } 353 354 /* twiddle thumbs until we get a signal */ 355 while (1) 356 sigpause(0); 357 358 /* NOTREACHED */ 359 } 360