sliplogin.c revision 1.16
1 /* $NetBSD: sliplogin.c,v 1.16 1998/07/04 21:04:02 mrg Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 __COPYRIGHT("@(#) Copyright (c) 1990, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"); 40 #endif /* not lint */ 41 42 #ifndef lint 43 #if 0 44 static char sccsid[] = "@(#)sliplogin.c 8.2 (Berkeley) 2/1/94"; 45 #else 46 __RCSID("$NetBSD: sliplogin.c,v 1.16 1998/07/04 21:04:02 mrg Exp $"); 47 #endif 48 #endif /* not lint */ 49 50 /* 51 * sliplogin.c 52 * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!] 53 * 54 * This program initializes its own tty port to be an async TCP/IP interface. 55 * It sets the line discipline to slip, invokes a shell script to initialize 56 * the network interface, then pauses forever waiting for hangup. 57 * 58 * It is a remote descendant of several similar programs with incestuous ties: 59 * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL. 60 * - slattach, probably by Rick Adams but touched by countless hordes. 61 * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it. 62 * 63 * There are two forms of usage: 64 * 65 * "sliplogin" 66 * Invoked simply as "sliplogin", the program looks up the username 67 * in the file /etc/slip.hosts. 68 * If an entry is found, the line on fd0 is configured for SLIP operation 69 * as specified in the file. 70 * 71 * "sliplogin IPhostlogin </dev/ttyb" 72 * Invoked by root with a username, the name is looked up in the 73 * /etc/slip.hosts file and if found fd0 is configured as in case 1. 74 */ 75 76 #include <sys/types.h> 77 #include <sys/file.h> 78 #include <sys/param.h> 79 #include <sys/socket.h> 80 #include <sys/stat.h> 81 #include <sys/syslog.h> 82 83 #if BSD >= 199006 84 #define POSIX 85 #endif 86 #ifdef POSIX 87 #include <termios.h> 88 #include <sys/ioctl.h> 89 #include <ttyent.h> 90 #else 91 #include <sgtty.h> 92 #endif 93 #include <net/slip.h> 94 95 #include <ctype.h> 96 #include <err.h> 97 #include <errno.h> 98 #include <netdb.h> 99 #include <signal.h> 100 #include <stdio.h> 101 #include <stdlib.h> 102 #include <string.h> 103 #include <unistd.h> 104 105 #include "pathnames.h" 106 107 int unit; 108 int speed; 109 int uid; 110 char loginargs[BUFSIZ]; 111 char loginfile[MAXPATHLEN]; 112 char loginname[BUFSIZ]; 113 114 void findid __P((char *)); 115 void hup_handler __P((int)); 116 int main __P((int, char **)); 117 const char *sigstr __P((int)); 118 119 void 120 findid(name) 121 char *name; 122 { 123 FILE *fp; 124 static char slopt[5][16]; 125 static char laddr[16]; 126 static char raddr[16]; 127 static char mask[16]; 128 char user[16]; 129 int n; 130 131 (void)strncpy(loginname, name, sizeof(loginname) - 1); 132 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 133 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 134 err(1, "%s", _PATH_ACCESS); 135 } 136 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 137 if (ferror(fp)) 138 break; 139 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 140 user, laddr, raddr, mask, slopt[0], slopt[1], 141 slopt[2], slopt[3], slopt[4]); 142 if (user[0] == '#' || isspace(user[0])) 143 continue; 144 if (strcmp(user, name) != 0) 145 continue; 146 147 /* 148 * we've found the guy we're looking for -- see if 149 * there's a login file we can use. First check for 150 * one specific to this host. If none found, try for 151 * a generic one. 152 */ 153 (void)snprintf(loginfile, sizeof loginfile, "%s.%s", 154 _PATH_LOGIN, name); 155 if (access(loginfile, R_OK|X_OK) != 0) { 156 (void)strncpy(loginfile, _PATH_LOGIN, sizeof(loginfile) - 1); 157 if (access(loginfile, R_OK|X_OK)) { 158 fputs("access denied - no login file\n", 159 stderr); 160 syslog(LOG_ERR, 161 "access denied for %s - no %s\n", 162 name, _PATH_LOGIN); 163 exit(5); 164 } 165 } 166 167 (void)fclose(fp); 168 return; 169 } 170 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 171 errx(1, "SLIP access denied for %s", name); 172 /* NOTREACHED */ 173 } 174 175 const char * 176 sigstr(s) 177 int s; 178 { 179 180 if (s > 0 && s < NSIG) 181 return (sys_signame[s]); 182 else { 183 static char buf[32]; 184 185 (void)snprintf(buf, sizeof buf, "sig %d", s); 186 return (buf); 187 } 188 } 189 190 void 191 hup_handler(s) 192 int s; 193 { 194 char logoutfile[MAXPATHLEN]; 195 196 (void)snprintf(logoutfile, sizeof logoutfile, "%s.%s", _PATH_LOGOUT, 197 loginname); 198 if (access(logoutfile, R_OK|X_OK) != 0) 199 (void)strncpy(logoutfile, _PATH_LOGOUT, sizeof(logoutfile) - 1); 200 if (access(logoutfile, R_OK|X_OK) == 0) { 201 char logincmd[2*MAXPATHLEN+32]; 202 203 (void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", 204 logoutfile, unit, speed, loginargs); 205 (void)system(logincmd); 206 } 207 (void)close(0); 208 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 209 sigstr(s)); 210 exit(1); 211 /* NOTREACHED */ 212 } 213 214 int 215 main(argc, argv) 216 int argc; 217 char *argv[]; 218 { 219 int fd, s, ldisc, odisc; 220 char *name; 221 #ifdef POSIX 222 struct termios tios, otios; 223 #else 224 struct sgttyb tty, otty; 225 #endif 226 char logincmd[2*BUFSIZ+32]; 227 228 if (strlen(argv[0]) > MAXLOGNAME) 229 errx(1, "login %s too long", argv[0]); 230 if ((name = strrchr(argv[0], '/')) == NULL) 231 name = argv[0]; 232 s = getdtablesize(); 233 for (fd = 3 ; fd < s ; fd++) 234 (void)close(fd); 235 openlog(name, LOG_PID, LOG_DAEMON); 236 uid = getuid(); 237 if (argc > 1) { 238 findid(argv[1]); 239 240 /* 241 * Disassociate from current controlling terminal, if any, 242 * and ensure that the slip line is our controlling terminal. 243 */ 244 #ifdef POSIX 245 switch (fork()) { 246 case -1: 247 perror("fork"); 248 syslog(LOG_ERR, "could not fork: %m"); 249 exit(1); 250 case 0: 251 break; 252 default: 253 exit(0); 254 } 255 if (setsid() < 0) 256 perror("setsid"); 257 #else 258 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 259 extern char *ttyname(); 260 261 (void)ioctl(fd, TIOCNOTTY, (caddr_t)0); 262 (void)close(fd); 263 /* open slip tty again to acquire as controlling tty? */ 264 fd = open(ttyname(0), O_RDWR, 0); 265 if (fd >= 0) 266 (void)close(fd); 267 } 268 (void)setpgrp(0, getpid()); 269 #endif 270 if (argc > 2) { 271 if ((fd = open(argv[2], O_RDWR)) == -1) { 272 perror(argv[2]); 273 exit(2); 274 } 275 (void)dup2(fd, 0); 276 if (fd > 2) 277 close(fd); 278 } 279 #ifdef TIOCSCTTY 280 if (ioctl(STDIN_FILENO, TIOCSCTTY, (caddr_t)0) != 0) 281 perror("ioctl (TIOCSCTTY)"); 282 #endif 283 } else { 284 if ((name = getlogin()) == NULL) { 285 syslog(LOG_ERR, 286 "access denied - getlogin returned 0\n"); 287 errx(1, "access denied - no username"); 288 } 289 findid(name); 290 } 291 if (!isatty(STDIN_FILENO)) { 292 syslog(LOG_ERR, "stdin not a tty"); 293 errx(1, "stdin not a tty"); 294 } 295 (void)fchmod(STDIN_FILENO, 0600); 296 warnx("starting slip login for %s", loginname); 297 #ifdef POSIX 298 /* set up the line parameters */ 299 if (tcgetattr(STDIN_FILENO, &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(STDIN_FILENO, 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(STDIN_FILENO, 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(STDIN_FILENO, 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(STDIN_FILENO, TIOCGETD, (caddr_t)&odisc) < 0) { 327 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 328 exit(1); 329 } 330 ldisc = SLIPDISC; 331 if (ioctl(STDIN_FILENO, 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(STDIN_FILENO, 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)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", loginfile, 345 unit, speed, 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)) != NULL) { 368 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 369 loginname, s, loginfile); 370 (void)ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&odisc); 371 #ifdef POSIX 372 (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &otios); 373 #else 374 (void)ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&otty); 375 #endif 376 exit(6); 377 } 378 379 /* twiddle thumbs until we get a signal */ 380 while (1) 381 sigpause(0); 382 383 /* NOTREACHED */ 384 } 385
Indexes created Mon Sep 29 21:09:56 GMT 2025