sliplogin.c revision 1.7
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 1.7 1994/02/10 18:01:28 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/signal.h> 74 #include <sys/file.h> 75 #include <sys/syslog.h> 76 #include <netdb.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 <stdio.h> 91 #include <errno.h> 92 #include <ctype.h> 93 #include <string.h> 94 #include <unistd.h> 95 #include "pathnames.h" 96 97 int unit; 98 int speed; 99 int uid; 100 char loginargs[BUFSIZ]; 101 char loginfile[MAXPATHLEN]; 102 char loginname[BUFSIZ]; 103 104 void 105 findid(name) 106 char *name; 107 { 108 FILE *fp; 109 static char slopt[5][16]; 110 static char laddr[16]; 111 static char raddr[16]; 112 static char mask[16]; 113 char user[16]; 114 int i, j, n; 115 116 (void)strcpy(loginname, name); 117 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 118 (void)fprintf(stderr, "sliplogin: %s: %s\n", 119 _PATH_ACCESS, strerror(errno)); 120 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 121 exit(1); 122 } 123 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 124 if (ferror(fp)) 125 break; 126 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 127 user, laddr, raddr, mask, slopt[0], slopt[1], 128 slopt[2], slopt[3], slopt[4]); 129 if (user[0] == '#' || isspace(user[0])) 130 continue; 131 if (strcmp(user, name) != 0) 132 continue; 133 134 /* 135 * we've found the guy we're looking for -- see if 136 * there's a login file we can use. First check for 137 * one specific to this host. If none found, try for 138 * a generic one. 139 */ 140 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 141 if (access(loginfile, R_OK|X_OK) != 0) { 142 (void)strcpy(loginfile, _PATH_LOGIN); 143 if (access(loginfile, R_OK|X_OK)) { 144 fputs("access denied - no login file\n", 145 stderr); 146 syslog(LOG_ERR, 147 "access denied for %s - no %s\n", 148 name, _PATH_LOGIN); 149 exit(5); 150 } 151 } 152 153 (void) fclose(fp); 154 return; 155 } 156 (void)fprintf(stderr, "SLIP access denied for %s\n", name); 157 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 158 exit(4); 159 /* NOTREACHED */ 160 } 161 162 const char * 163 sigstr(s) 164 int s; 165 { 166 if (s > 0 && s < NSIG) 167 return(sys_signame[s]); 168 else { 169 static char buf[32]; 170 (void)sprintf(buf, "sig %d", s); 171 return(buf); 172 } 173 } 174 175 void 176 hup_handler(s) 177 int s; 178 { 179 char logoutfile[MAXPATHLEN]; 180 181 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname); 182 if (access(logoutfile, R_OK|X_OK) != 0) 183 (void)strcpy(logoutfile, _PATH_LOGOUT); 184 if (access(logoutfile, R_OK|X_OK) == 0) { 185 char logincmd[2*MAXPATHLEN+32]; 186 187 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 188 loginargs); 189 (void) system(logincmd); 190 } 191 (void) close(0); 192 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 193 sigstr(s)); 194 exit(1); 195 /* NOTREACHED */ 196 } 197 198 main(argc, argv) 199 int argc; 200 char *argv[]; 201 { 202 int fd, s, ldisc, odisc; 203 char *name; 204 #ifdef POSIX 205 struct termios tios, otios; 206 #else 207 struct sgttyb tty, otty; 208 #endif 209 char logincmd[2*BUFSIZ+32]; 210 extern uid_t getuid(); 211 212 if ((name = strrchr(argv[0], '/')) == NULL) 213 name = argv[0]; 214 s = getdtablesize(); 215 for (fd = 3 ; fd < s ; fd++) 216 (void) close(fd); 217 openlog(name, LOG_PID, LOG_DAEMON); 218 uid = getuid(); 219 if (argc > 1) { 220 findid(argv[1]); 221 222 /* 223 * Disassociate from current controlling terminal, if any, 224 * and ensure that the slip line is our controlling terminal. 225 */ 226 #ifdef POSIX 227 if (fork() > 0) 228 exit(0); 229 if (setsid() < 0) 230 perror("setsid"); 231 #else 232 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 233 extern char *ttyname(); 234 235 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 236 (void) close(fd); 237 /* open slip tty again to acquire as controlling tty? */ 238 fd = open(ttyname(0), O_RDWR, 0); 239 if (fd >= 0) 240 (void) close(fd); 241 } 242 (void) setpgrp(0, getpid()); 243 #endif 244 if (argc > 2) { 245 if ((fd = open(argv[2], O_RDWR)) == -1) { 246 perror(argv[2]); 247 exit(2); 248 } 249 (void) dup2(fd, 0); 250 if (fd > 2) 251 close(fd); 252 } 253 #ifdef TIOCSCTTY 254 if (ioctl(0, TIOCSCTTY, (caddr_t)0) != 0) 255 perror("ioctl (TIOCSCTTY)"); 256 #endif 257 } else { 258 extern char *getlogin(); 259 260 if ((name = getlogin()) == NULL) { 261 (void) fprintf(stderr, "access denied - no username\n"); 262 syslog(LOG_ERR, "access denied - getlogin returned 0\n"); 263 exit(1); 264 } 265 findid(name); 266 } 267 (void) fchmod(0, 0600); 268 (void) fprintf(stderr, "starting slip login for %s\n", loginname); 269 #ifdef POSIX 270 /* set up the line parameters */ 271 if (tcgetattr(0, &tios) < 0) { 272 syslog(LOG_ERR, "tcgetattr: %m"); 273 exit(1); 274 } 275 otios = tios; 276 cfmakeraw(&tios); 277 tios.c_iflag &= ~IMAXBEL; 278 if (tcsetattr(0, TCSAFLUSH, &tios) < 0) { 279 syslog(LOG_ERR, "tcsetattr: %m"); 280 exit(1); 281 } 282 speed = cfgetispeed(&tios); 283 #else 284 /* set up the line parameters */ 285 if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) { 286 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 287 exit(1); 288 } 289 otty = tty; 290 speed = tty.sg_ispeed; 291 tty.sg_flags = RAW | ANYP; 292 if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) { 293 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 294 exit(1); 295 } 296 #endif 297 /* find out what ldisc we started with */ 298 if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) { 299 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 300 exit(1); 301 } 302 ldisc = SLIPDISC; 303 if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) { 304 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 305 exit(1); 306 } 307 /* find out what unit number we were assigned */ 308 if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) { 309 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 310 exit(1); 311 } 312 (void) signal(SIGHUP, hup_handler); 313 (void) signal(SIGTERM, hup_handler); 314 315 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 316 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 317 loginargs); 318 /* 319 * aim stdout and errout at /dev/null so logincmd output won't 320 * babble into the slip tty line. 321 */ 322 (void) close(1); 323 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 324 if (fd < 0) { 325 syslog(LOG_ERR, "open /dev/null: %m"); 326 exit(1); 327 } 328 (void) dup2(fd, 1); 329 (void) close(fd); 330 } 331 (void) dup2(1, 2); 332 333 /* 334 * Run login and logout scripts as root (real and effective); 335 * current route(8) is setuid root, and checks the real uid 336 * to see whether changes are allowed (or just "route get"). 337 */ 338 (void) setuid(0); 339 if (s = system(logincmd)) { 340 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 341 loginname, s, loginfile); 342 (void) ioctl(0, TIOCSETD, (caddr_t)&odisc); 343 exit(6); 344 } 345 346 /* twiddle thumbs until we get a signal */ 347 while (1) 348 sigpause(0); 349 350 /* NOTREACHED */ 351 } 352
Indexes created Sat Sep 27 14:09:57 GMT 2025