sliplogin.c revision 1.1
1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 char copyright[] = 36 "@(#) Copyright (c) 1990 The Regents of the University of California.\n\ 37 All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 static char sccsid[] = "@(#)sliplogin.c 5.6 (Berkeley) 3/2/91"; 42 #endif /* not lint */ 43 44 /* 45 * sliplogin.c 46 * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!] 47 * 48 * This program initializes its own tty port to be an async TCP/IP interface. 49 * It sets the line discipline to slip, invokes a shell script to initialize 50 * the network interface, then pauses forever waiting for hangup. 51 * 52 * It is a remote descendant of several similar programs with incestuous ties: 53 * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL. 54 * - slattach, probably by Rick Adams but touched by countless hordes. 55 * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it. 56 * 57 * There are two forms of usage: 58 * 59 * "sliplogin" 60 * Invoked simply as "sliplogin", the program looks up the username 61 * in the file /etc/slip.hosts. 62 * If an entry is found, the line on fd0 is configured for SLIP operation 63 * as specified in the file. 64 * 65 * "sliplogin IPhostlogin </dev/ttyb" 66 * Invoked by root with a username, the name is looked up in the 67 * /etc/slip.hosts file and if found fd0 is configured as in case 1. 68 */ 69 70 #include <sys/param.h> 71 #include <sys/socket.h> 72 #include <sys/signal.h> 73 #include <sys/file.h> 74 #include <sys/syslog.h> 75 #include <netdb.h> 76 77 #if BSD >= 199006 78 #define POSIX 79 #endif 80 #ifdef POSIX 81 #include <sys/termios.h> 82 #include <sys/ioctl.h> 83 #include <ttyent.h> 84 #else 85 #include <sgtty.h> 86 #endif 87 #include <netinet/in.h> 88 #include <net/if.h> 89 #include <net/if_slvar.h> 90 91 #include <stdio.h> 92 #include <errno.h> 93 #include <ctype.h> 94 #include <string.h> 95 #include "pathnames.h" 96 97 int unit; 98 int slip_mode; 99 int speed; 100 int uid; 101 char loginargs[BUFSIZ]; 102 char loginfile[MAXPATHLEN]; 103 char loginname[BUFSIZ]; 104 105 struct slip_modes { 106 char *sm_name; 107 int sm_value; 108 } modes[] = { 109 "normal", 0, 110 "compress", SC_COMPRESS, 111 "noicmp", SC_NOICMP, 112 "autocomp", SC_AUTOCOMP 113 }; 114 115 void 116 findid(name) 117 char *name; 118 { 119 FILE *fp; 120 static char slopt[5][16]; 121 static char laddr[16]; 122 static char raddr[16]; 123 static char mask[16]; 124 char user[16]; 125 int i, j, n; 126 127 (void)strcpy(loginname, name); 128 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 129 (void)fprintf(stderr, "sliplogin: %s: %s\n", 130 _PATH_ACCESS, strerror(errno)); 131 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 132 exit(1); 133 } 134 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 135 if (ferror(fp)) 136 break; 137 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 138 user, laddr, raddr, mask, slopt[0], slopt[1], 139 slopt[2], slopt[3], slopt[4]); 140 if (user[0] == '#' || isspace(user[0])) 141 continue; 142 if (strcmp(user, name) != 0) 143 continue; 144 145 slip_mode = 0; 146 for (i = 0; i < n - 4; i++) { 147 for (j = 0; j < sizeof(modes)/sizeof(struct slip_modes); 148 j++) { 149 if (strcmp(modes[j].sm_name, slopt[i]) == 0) { 150 slip_mode |= modes[j].sm_value; 151 break; 152 } 153 } 154 } 155 156 /* 157 * we've found the guy we're looking for -- see if 158 * there's a login file we can use. First check for 159 * one specific to this host. If none found, try for 160 * a generic one. 161 */ 162 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 163 if (access(loginfile, R_OK|X_OK) != 0) { 164 (void)strcpy(loginfile, _PATH_LOGIN); 165 if (access(loginfile, R_OK|X_OK)) { 166 fputs("access denied - no login file\n", 167 stderr); 168 syslog(LOG_ERR, 169 "access denied for %s - no %s\n", 170 name, _PATH_LOGIN); 171 exit(5); 172 } 173 } 174 175 (void) fclose(fp); 176 return; 177 } 178 (void)fprintf(stderr, "SLIP access denied for %s\n", name); 179 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 180 exit(4); 181 /* NOTREACHED */ 182 } 183 184 char * 185 sigstr(s) 186 int s; 187 { 188 static char buf[32]; 189 190 switch (s) { 191 case SIGHUP: return("HUP"); 192 case SIGINT: return("INT"); 193 case SIGQUIT: return("QUIT"); 194 case SIGILL: return("ILL"); 195 case SIGTRAP: return("TRAP"); 196 case SIGIOT: return("IOT"); 197 case SIGEMT: return("EMT"); 198 case SIGFPE: return("FPE"); 199 case SIGKILL: return("KILL"); 200 case SIGBUS: return("BUS"); 201 case SIGSEGV: return("SEGV"); 202 case SIGSYS: return("SYS"); 203 case SIGPIPE: return("PIPE"); 204 case SIGALRM: return("ALRM"); 205 case SIGTERM: return("TERM"); 206 case SIGURG: return("URG"); 207 case SIGSTOP: return("STOP"); 208 case SIGTSTP: return("TSTP"); 209 case SIGCONT: return("CONT"); 210 case SIGCHLD: return("CHLD"); 211 case SIGTTIN: return("TTIN"); 212 case SIGTTOU: return("TTOU"); 213 case SIGIO: return("IO"); 214 case SIGXCPU: return("XCPU"); 215 case SIGXFSZ: return("XFSZ"); 216 case SIGVTALRM: return("VTALRM"); 217 case SIGPROF: return("PROF"); 218 case SIGWINCH: return("WINCH"); 219 #ifdef SIGLOST 220 case SIGLOST: return("LOST"); 221 #endif 222 case SIGUSR1: return("USR1"); 223 case SIGUSR2: return("USR2"); 224 } 225 (void)sprintf(buf, "sig %d", s); 226 return(buf); 227 } 228 229 void 230 hup_handler(s) 231 int s; 232 { 233 char logoutfile[MAXPATHLEN]; 234 235 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname); 236 if (access(logoutfile, R_OK|X_OK) != 0) 237 (void)strcpy(logoutfile, _PATH_LOGOUT); 238 if (access(logoutfile, R_OK|X_OK) == 0) { 239 char logincmd[2*MAXPATHLEN+32]; 240 241 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 242 loginargs); 243 (void) system(logincmd); 244 } 245 (void) close(0); 246 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 247 sigstr(s)); 248 exit(1); 249 /* NOTREACHED */ 250 } 251 252 main(argc, argv) 253 int argc; 254 char *argv[]; 255 { 256 int fd, s, ldisc, odisc; 257 char *name; 258 #ifdef POSIX 259 struct termios tios, otios; 260 #else 261 struct sgttyb tty, otty; 262 #endif 263 char logincmd[2*BUFSIZ+32]; 264 extern uid_t getuid(); 265 266 if ((name = strrchr(argv[0], '/')) == NULL) 267 name = argv[0]; 268 s = getdtablesize(); 269 for (fd = 3 ; fd < s ; fd++) 270 (void) close(fd); 271 openlog(name, LOG_PID, LOG_DAEMON); 272 uid = getuid(); 273 if (argc > 1) { 274 findid(argv[1]); 275 276 /* 277 * Disassociate from current controlling terminal, if any, 278 * and ensure that the slip line is our controlling terminal. 279 */ 280 #ifdef POSIX 281 if (fork() > 0) 282 exit(0); 283 if (setsid() != 0) 284 perror("setsid"); 285 #else 286 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 287 extern char *ttyname(); 288 289 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 290 (void) close(fd); 291 /* open slip tty again to acquire as controlling tty? */ 292 fd = open(ttyname(0), O_RDWR, 0); 293 if (fd >= 0) 294 (void) close(fd); 295 } 296 (void) setpgrp(0, getpid()); 297 #endif 298 if (argc > 2) { 299 if ((fd = open(argv[2], O_RDWR)) == -1) { 300 perror(argv[2]); 301 exit(2); 302 } 303 (void) dup2(fd, 0); 304 if (fd > 2) 305 close(fd); 306 } 307 #ifdef TIOCSCTTY 308 if (ioctl(0, TIOCSCTTY, (caddr_t)0) != 0) 309 perror("ioctl (TIOCSCTTY)"); 310 #endif 311 } else { 312 extern char *getlogin(); 313 314 if ((name = getlogin()) == NULL) { 315 (void) fprintf(stderr, "access denied - no username\n"); 316 syslog(LOG_ERR, "access denied - getlogin returned 0\n"); 317 exit(1); 318 } 319 findid(name); 320 } 321 (void) fchmod(0, 0600); 322 (void) fprintf(stderr, "starting slip login for %s\n", loginname); 323 #ifdef POSIX 324 /* set up the line parameters */ 325 if (tcgetattr(0, &tios) < 0) { 326 syslog(LOG_ERR, "tcgetattr: %m"); 327 exit(1); 328 } 329 otios = tios; 330 cfmakeraw(&tios); 331 tios.c_iflag &= ~IMAXBEL; 332 if (tcsetattr(0, TCSAFLUSH, &tios) < 0) { 333 syslog(LOG_ERR, "tcsetattr: %m"); 334 exit(1); 335 } 336 speed = cfgetispeed(&tios); 337 #else 338 /* set up the line parameters */ 339 if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) { 340 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 341 exit(1); 342 } 343 otty = tty; 344 speed = tty.sg_ispeed; 345 tty.sg_flags = RAW | ANYP; 346 if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) { 347 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 348 exit(1); 349 } 350 #endif 351 /* find out what ldisc we started with */ 352 if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) { 353 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 354 exit(1); 355 } 356 ldisc = SLIPDISC; 357 if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) { 358 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 359 exit(1); 360 } 361 /* find out what unit number we were assigned */ 362 if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) { 363 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 364 exit(1); 365 } 366 (void) signal(SIGHUP, hup_handler); 367 (void) signal(SIGTERM, hup_handler); 368 369 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 370 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 371 loginargs); 372 /* 373 * aim stdout and errout at /dev/null so logincmd output won't 374 * babble into the slip tty line. 375 */ 376 (void) close(1); 377 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 378 if (fd < 0) { 379 syslog(LOG_ERR, "open /dev/null: %m"); 380 exit(1); 381 } 382 (void) dup2(fd, 1); 383 (void) close(fd); 384 } 385 (void) dup2(1, 2); 386 387 /* 388 * Run login and logout scripts as root (real and effective); 389 * current route(8) is setuid root, and checks the real uid 390 * to see whether changes are allowed (or just "route get"). 391 */ 392 (void) setuid(0); 393 if (s = system(logincmd)) { 394 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 395 loginname, s, loginfile); 396 (void) ioctl(0, TIOCSETD, (caddr_t)&odisc); 397 exit(6); 398 } 399 if (ioctl(0, SLIOCSFLAGS, (caddr_t)&slip_mode) < 0) { 400 syslog(LOG_ERR, "ioctl (SLIOCSFLAGS): %m"); 401 exit(1); 402 } 403 404 /* twiddle thumbs until we get a signal */ 405 while (1) 406 sigpause(0); 407 408 /* NOTREACHED */ 409 } 410
Indexes created Sat Sep 27 14:09:57 GMT 2025