sliplogin.c revision 1.14
1 /* $NetBSD: sliplogin.c,v 1.14 1997/10/17 13:36:53 lukem 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 1.14 1997/10/17 13:36:53 lukem 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 #include <netdb.h> 83 #include <signal.h> 84 #include <stdlib.h> 85 86 #if BSD >= 199006 87 #define POSIX 88 #endif 89 #ifdef POSIX 90 #include <termios.h> 91 #include <sys/ioctl.h> 92 #include <ttyent.h> 93 #else 94 #include <sgtty.h> 95 #endif 96 #include <net/slip.h> 97 98 #include <ctype.h> 99 #include <err.h> 100 #include <errno.h> 101 #include <stdio.h> 102 #include <string.h> 103 #include <unistd.h> 104 #include "pathnames.h" 105 106 int unit; 107 int speed; 108 int uid; 109 char loginargs[BUFSIZ]; 110 char loginfile[MAXPATHLEN]; 111 char loginname[BUFSIZ]; 112 113 void findid __P((char *)); 114 void hup_handler __P((int)); 115 int main __P((int, char **)); 116 const char *sigstr __P((int)); 117 118 void 119 findid(name) 120 char *name; 121 { 122 FILE *fp; 123 static char slopt[5][16]; 124 static char laddr[16]; 125 static char raddr[16]; 126 static char mask[16]; 127 char user[16]; 128 int n; 129 130 (void)strncpy(loginname, name, sizeof(loginname) - 1); 131 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 132 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 133 err(1, "%s", _PATH_ACCESS); 134 } 135 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 136 if (ferror(fp)) 137 break; 138 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 139 user, laddr, raddr, mask, slopt[0], slopt[1], 140 slopt[2], slopt[3], slopt[4]); 141 if (user[0] == '#' || isspace(user[0])) 142 continue; 143 if (strcmp(user, name) != 0) 144 continue; 145 146 /* 147 * we've found the guy we're looking for -- see if 148 * there's a login file we can use. First check for 149 * one specific to this host. If none found, try for 150 * a generic one. 151 */ 152 (void)snprintf(loginfile, sizeof loginfile, "%s.%s", 153 _PATH_LOGIN, name); 154 if (access(loginfile, R_OK|X_OK) != 0) { 155 (void)strncpy(loginfile, _PATH_LOGIN, sizeof(loginfile) - 1); 156 if (access(loginfile, R_OK|X_OK)) { 157 fputs("access denied - no login file\n", 158 stderr); 159 syslog(LOG_ERR, 160 "access denied for %s - no %s\n", 161 name, _PATH_LOGIN); 162 exit(5); 163 } 164 } 165 166 (void) fclose(fp); 167 return; 168 } 169 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 170 errx(1, "SLIP access denied for %s", name); 171 /* NOTREACHED */ 172 } 173 174 const char * 175 sigstr(s) 176 int s; 177 { 178 if (s > 0 && s < NSIG) 179 return(sys_signame[s]); 180 else { 181 static char buf[32]; 182 183 (void)snprintf(buf, sizeof buf, "sig %d", s); 184 return(buf); 185 } 186 } 187 188 void 189 hup_handler(s) 190 int s; 191 { 192 char logoutfile[MAXPATHLEN]; 193 194 (void)snprintf(logoutfile, sizeof logoutfile, "%s.%s", _PATH_LOGOUT, 195 loginname); 196 if (access(logoutfile, R_OK|X_OK) != 0) 197 (void)strncpy(logoutfile, _PATH_LOGOUT, sizeof(logoutfile) - 1); 198 if (access(logoutfile, R_OK|X_OK) == 0) { 199 char logincmd[2*MAXPATHLEN+32]; 200 201 (void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", 202 logoutfile, unit, speed, loginargs); 203 (void) system(logincmd); 204 } 205 (void) close(0); 206 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 207 sigstr(s)); 208 exit(1); 209 /* NOTREACHED */ 210 } 211 212 int 213 main(argc, argv) 214 int argc; 215 char *argv[]; 216 { 217 int fd, s, ldisc, odisc; 218 char *name; 219 #ifdef POSIX 220 struct termios tios, otios; 221 #else 222 struct sgttyb tty, otty; 223 #endif 224 char logincmd[2*BUFSIZ+32]; 225 226 if ((name = strrchr(argv[0], '/')) == NULL) 227 name = argv[0]; 228 s = getdtablesize(); 229 for (fd = 3 ; fd < s ; fd++) 230 (void) close(fd); 231 openlog(name, LOG_PID, LOG_DAEMON); 232 uid = getuid(); 233 if (argc > 1) { 234 findid(argv[1]); 235 236 /* 237 * Disassociate from current controlling terminal, if any, 238 * and ensure that the slip line is our controlling terminal. 239 */ 240 #ifdef POSIX 241 if (fork() > 0) 242 exit(0); 243 if (setsid() < 0) 244 perror("setsid"); 245 #else 246 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 247 extern char *ttyname(); 248 249 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 250 (void) close(fd); 251 /* open slip tty again to acquire as controlling tty? */ 252 fd = open(ttyname(0), O_RDWR, 0); 253 if (fd >= 0) 254 (void) close(fd); 255 } 256 (void) setpgrp(0, getpid()); 257 #endif 258 if (argc > 2) { 259 if ((fd = open(argv[2], O_RDWR)) == -1) { 260 perror(argv[2]); 261 exit(2); 262 } 263 (void) dup2(fd, 0); 264 if (fd > 2) 265 close(fd); 266 } 267 #ifdef TIOCSCTTY 268 if (ioctl(STDIN_FILENO, TIOCSCTTY, (caddr_t)0) != 0) 269 perror("ioctl (TIOCSCTTY)"); 270 #endif 271 } else { 272 if ((name = getlogin()) == NULL) { 273 syslog(LOG_ERR, 274 "access denied - getlogin returned 0\n"); 275 errx(1, "access denied - no username"); 276 } 277 findid(name); 278 } 279 if (!isatty(STDIN_FILENO)) { 280 syslog(LOG_ERR, "stdin not a tty"); 281 errx(1, "stdin not a tty"); 282 } 283 (void) fchmod(STDIN_FILENO, 0600); 284 warnx("starting slip login for %s", loginname); 285 #ifdef POSIX 286 /* set up the line parameters */ 287 if (tcgetattr(STDIN_FILENO, &tios) < 0) { 288 syslog(LOG_ERR, "tcgetattr: %m"); 289 exit(1); 290 } 291 otios = tios; 292 cfmakeraw(&tios); 293 tios.c_iflag &= ~IMAXBEL; 294 if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tios) < 0) { 295 syslog(LOG_ERR, "tcsetattr: %m"); 296 exit(1); 297 } 298 speed = cfgetispeed(&tios); 299 #else 300 /* set up the line parameters */ 301 if (ioctl(STDIN_FILENO, TIOCGETP, (caddr_t)&tty) < 0) { 302 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 303 exit(1); 304 } 305 otty = tty; 306 speed = tty.sg_ispeed; 307 tty.sg_flags = RAW | ANYP; 308 if (ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&tty) < 0) { 309 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 310 exit(1); 311 } 312 #endif 313 /* find out what ldisc we started with */ 314 if (ioctl(STDIN_FILENO, TIOCGETD, (caddr_t)&odisc) < 0) { 315 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 316 exit(1); 317 } 318 ldisc = SLIPDISC; 319 if (ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&ldisc) < 0) { 320 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 321 exit(1); 322 } 323 /* find out what unit number we were assigned */ 324 if (ioctl(STDIN_FILENO, SLIOCGUNIT, (caddr_t)&unit) < 0) { 325 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 326 exit(1); 327 } 328 (void) signal(SIGHUP, hup_handler); 329 (void) signal(SIGTERM, hup_handler); 330 331 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 332 (void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", loginfile, 333 unit, speed, loginargs); 334 /* 335 * aim stdout and errout at /dev/null so logincmd output won't 336 * babble into the slip tty line. 337 */ 338 (void) close(1); 339 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 340 if (fd < 0) { 341 syslog(LOG_ERR, "open /dev/null: %m"); 342 exit(1); 343 } 344 (void) dup2(fd, 1); 345 (void) close(fd); 346 } 347 (void) dup2(1, 2); 348 349 /* 350 * Run login and logout scripts as root (real and effective); 351 * current route(8) is setuid root, and checks the real uid 352 * to see whether changes are allowed (or just "route get"). 353 */ 354 (void) setuid(0); 355 if ((s = system(logincmd)) != NULL) { 356 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 357 loginname, s, loginfile); 358 (void) ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&odisc); 359 #ifdef POSIX 360 (void) tcsetattr(STDIN_FILENO, TCSAFLUSH, &otios); 361 #else 362 (void) ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&otty); 363 #endif 364 exit(6); 365 } 366 367 /* twiddle thumbs until we get a signal */ 368 while (1) 369 sigpause(0); 370 371 /* NOTREACHED */ 372 } 373
Indexes created Sat Sep 27 14:09:57 GMT 2025