sliplogin.c revision 1.10
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[] = "from: @(#)sliplogin.c 5.6 (Berkeley) 3/2/91";*/ 42 static char rcsid[] = "$Id: sliplogin.c,v 1.10 1994/05/14 21:43:45 cgd Exp $"; 43 #endif /* not lint */ 44 45 /* 46 * sliplogin.c 47 * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!] 48 * 49 * This program initializes its own tty port to be an async TCP/IP interface. 50 * It sets the line discipline to slip, invokes a shell script to initialize 51 * the network interface, then pauses forever waiting for hangup. 52 * 53 * It is a remote descendant of several similar programs with incestuous ties: 54 * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL. 55 * - slattach, probably by Rick Adams but touched by countless hordes. 56 * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it. 57 * 58 * There are two forms of usage: 59 * 60 * "sliplogin" 61 * Invoked simply as "sliplogin", the program looks up the username 62 * in the file /etc/slip.hosts. 63 * If an entry is found, the line on fd0 is configured for SLIP operation 64 * as specified in the file. 65 * 66 * "sliplogin IPhostlogin </dev/ttyb" 67 * Invoked by root with a username, the name is looked up in the 68 * /etc/slip.hosts file and if found fd0 is configured as in case 1. 69 */ 70 71 #include <sys/param.h> 72 #include <sys/socket.h> 73 #include <sys/file.h> 74 #include <sys/syslog.h> 75 #include <netdb.h> 76 #include <signal.h> 77 78 #if BSD >= 199006 79 #define POSIX 80 #endif 81 #ifdef POSIX 82 #include <sys/termios.h> 83 #include <sys/ioctl.h> 84 #include <ttyent.h> 85 #else 86 #include <sgtty.h> 87 #endif 88 #include <net/slip.h> 89 90 #include <ctype.h> 91 #include <err.h> 92 #include <errno.h> 93 #include <stdio.h> 94 #include <string.h> 95 #include <unistd.h> 96 #include "pathnames.h" 97 98 int unit; 99 int speed; 100 int uid; 101 char loginargs[BUFSIZ]; 102 char loginfile[MAXPATHLEN]; 103 char loginname[BUFSIZ]; 104 105 void 106 findid(name) 107 char *name; 108 { 109 FILE *fp; 110 static char slopt[5][16]; 111 static char laddr[16]; 112 static char raddr[16]; 113 static char mask[16]; 114 char user[16]; 115 int i, j, n; 116 117 (void)strcpy(loginname, name); 118 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 119 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 120 err(1, "%s", _PATH_ACCESS); 121 } 122 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 123 if (ferror(fp)) 124 break; 125 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 126 user, laddr, raddr, mask, slopt[0], slopt[1], 127 slopt[2], slopt[3], slopt[4]); 128 if (user[0] == '#' || isspace(user[0])) 129 continue; 130 if (strcmp(user, name) != 0) 131 continue; 132 133 /* 134 * we've found the guy we're looking for -- see if 135 * there's a login file we can use. First check for 136 * one specific to this host. If none found, try for 137 * a generic one. 138 */ 139 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 140 if (access(loginfile, R_OK|X_OK) != 0) { 141 (void)strcpy(loginfile, _PATH_LOGIN); 142 if (access(loginfile, R_OK|X_OK)) { 143 fputs("access denied - no login file\n", 144 stderr); 145 syslog(LOG_ERR, 146 "access denied for %s - no %s\n", 147 name, _PATH_LOGIN); 148 exit(5); 149 } 150 } 151 152 (void) fclose(fp); 153 return; 154 } 155 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 156 errx(1, "SLIP access denied for %s", name); 157 /* NOTREACHED */ 158 } 159 160 const char * 161 sigstr(s) 162 int s; 163 { 164 if (s > 0 && s < NSIG) 165 return(sys_signame[s]); 166 else { 167 static char buf[32]; 168 (void)sprintf(buf, "sig %d", s); 169 return(buf); 170 } 171 } 172 173 void 174 hup_handler(s) 175 int s; 176 { 177 char logoutfile[MAXPATHLEN]; 178 179 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname); 180 if (access(logoutfile, R_OK|X_OK) != 0) 181 (void)strcpy(logoutfile, _PATH_LOGOUT); 182 if (access(logoutfile, R_OK|X_OK) == 0) { 183 char logincmd[2*MAXPATHLEN+32]; 184 185 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 186 loginargs); 187 (void) system(logincmd); 188 } 189 (void) close(0); 190 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 191 sigstr(s)); 192 exit(1); 193 /* NOTREACHED */ 194 } 195 196 main(argc, argv) 197 int argc; 198 char *argv[]; 199 { 200 int fd, s, ldisc, odisc; 201 char *name; 202 #ifdef POSIX 203 struct termios tios, otios; 204 #else 205 struct sgttyb tty, otty; 206 #endif 207 char logincmd[2*BUFSIZ+32]; 208 extern uid_t getuid(); 209 210 if ((name = strrchr(argv[0], '/')) == NULL) 211 name = argv[0]; 212 s = getdtablesize(); 213 for (fd = 3 ; fd < s ; fd++) 214 (void) close(fd); 215 openlog(name, LOG_PID, LOG_DAEMON); 216 uid = getuid(); 217 if (argc > 1) { 218 findid(argv[1]); 219 220 /* 221 * Disassociate from current controlling terminal, if any, 222 * and ensure that the slip line is our controlling terminal. 223 */ 224 #ifdef POSIX 225 if (fork() > 0) 226 exit(0); 227 if (setsid() < 0) 228 perror("setsid"); 229 #else 230 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 231 extern char *ttyname(); 232 233 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 234 (void) close(fd); 235 /* open slip tty again to acquire as controlling tty? */ 236 fd = open(ttyname(0), O_RDWR, 0); 237 if (fd >= 0) 238 (void) close(fd); 239 } 240 (void) setpgrp(0, getpid()); 241 #endif 242 if (argc > 2) { 243 if ((fd = open(argv[2], O_RDWR)) == -1) { 244 perror(argv[2]); 245 exit(2); 246 } 247 (void) dup2(fd, 0); 248 if (fd > 2) 249 close(fd); 250 } 251 #ifdef TIOCSCTTY 252 if (ioctl(STDIN_FILENO, TIOCSCTTY, (caddr_t)0) != 0) 253 perror("ioctl (TIOCSCTTY)"); 254 #endif 255 } else { 256 extern char *getlogin(); 257 258 if ((name = getlogin()) == NULL) { 259 syslog(LOG_ERR, 260 "access denied - getlogin returned 0\n"); 261 errx(1, "access denied - no username"); 262 } 263 findid(name); 264 } 265 if (!isatty(STDIN_FILENO)) { 266 syslog(LOG_ERR, "stdin not a tty"); 267 errx(1, "stdin not a tty"); 268 } 269 (void) fchmod(STDIN_FILENO, 0600); 270 warnx("starting slip login for %s", loginname); 271 #ifdef POSIX 272 /* set up the line parameters */ 273 if (tcgetattr(STDIN_FILENO, &tios) < 0) { 274 syslog(LOG_ERR, "tcgetattr: %m"); 275 exit(1); 276 } 277 otios = tios; 278 cfmakeraw(&tios); 279 tios.c_iflag &= ~IMAXBEL; 280 if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tios) < 0) { 281 syslog(LOG_ERR, "tcsetattr: %m"); 282 exit(1); 283 } 284 speed = cfgetispeed(&tios); 285 #else 286 /* set up the line parameters */ 287 if (ioctl(STDIN_FILENO, TIOCGETP, (caddr_t)&tty) < 0) { 288 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 289 exit(1); 290 } 291 otty = tty; 292 speed = tty.sg_ispeed; 293 tty.sg_flags = RAW | ANYP; 294 if (ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&tty) < 0) { 295 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 296 exit(1); 297 } 298 #endif 299 /* find out what ldisc we started with */ 300 if (ioctl(STDIN_FILENO, TIOCGETD, (caddr_t)&odisc) < 0) { 301 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 302 exit(1); 303 } 304 ldisc = SLIPDISC; 305 if (ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&ldisc) < 0) { 306 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 307 exit(1); 308 } 309 /* find out what unit number we were assigned */ 310 if (ioctl(STDIN_FILENO, SLIOCGUNIT, (caddr_t)&unit) < 0) { 311 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 312 exit(1); 313 } 314 (void) signal(SIGHUP, hup_handler); 315 (void) signal(SIGTERM, hup_handler); 316 317 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 318 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 319 loginargs); 320 /* 321 * aim stdout and errout at /dev/null so logincmd output won't 322 * babble into the slip tty line. 323 */ 324 (void) close(1); 325 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 326 if (fd < 0) { 327 syslog(LOG_ERR, "open /dev/null: %m"); 328 exit(1); 329 } 330 (void) dup2(fd, 1); 331 (void) close(fd); 332 } 333 (void) dup2(1, 2); 334 335 /* 336 * Run login and logout scripts as root (real and effective); 337 * current route(8) is setuid root, and checks the real uid 338 * to see whether changes are allowed (or just "route get"). 339 */ 340 (void) setuid(0); 341 if (s = system(logincmd)) { 342 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 343 loginname, s, loginfile); 344 (void) ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&odisc); 345 #ifdef POSIX 346 (void) tcsetattr(STDIN_FILENO, TCSAFLUSH, &otios); 347 #else 348 (void) ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&otty); 349 #endif 350 exit(6); 351 } 352 353 /* twiddle thumbs until we get a signal */ 354 while (1) 355 sigpause(0); 356 357 /* NOTREACHED */ 358 } 359
Indexes created Sun Sep 28 12:09:53 GMT 2025