sliplogin.c revision 1.4
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 1.4 1993/08/06 22:18:26 mycroft 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 <netinet/in.h> 89 #include <net/if.h> 90 #include <net/if_slvar.h> 91 92 #include <stdio.h> 93 #include <errno.h> 94 #include <ctype.h> 95 #include <string.h> 96 #include <unistd.h> 97 #include "pathnames.h" 98 99 int unit; 100 int slip_mode; 101 int speed; 102 int uid; 103 char loginargs[BUFSIZ]; 104 char loginfile[MAXPATHLEN]; 105 char loginname[BUFSIZ]; 106 107 struct slip_modes { 108 char *sm_name; 109 int sm_value; 110 } modes[] = { 111 "normal", 0, 112 "compress", SC_COMPRESS, 113 "noicmp", SC_NOICMP, 114 "autocomp", SC_AUTOCOMP 115 }; 116 117 void 118 findid(name) 119 char *name; 120 { 121 FILE *fp; 122 static char slopt[5][16]; 123 static char laddr[16]; 124 static char raddr[16]; 125 static char mask[16]; 126 char user[16]; 127 int i, j, n; 128 129 (void)strcpy(loginname, name); 130 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 131 (void)fprintf(stderr, "sliplogin: %s: %s\n", 132 _PATH_ACCESS, strerror(errno)); 133 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 134 exit(1); 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 slip_mode = 0; 148 for (i = 0; i < n - 4; i++) { 149 for (j = 0; j < sizeof(modes)/sizeof(struct slip_modes); 150 j++) { 151 if (strcmp(modes[j].sm_name, slopt[i]) == 0) { 152 slip_mode |= modes[j].sm_value; 153 break; 154 } 155 } 156 } 157 158 /* 159 * we've found the guy we're looking for -- see if 160 * there's a login file we can use. First check for 161 * one specific to this host. If none found, try for 162 * a generic one. 163 */ 164 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name); 165 if (access(loginfile, R_OK|X_OK) != 0) { 166 (void)strcpy(loginfile, _PATH_LOGIN); 167 if (access(loginfile, R_OK|X_OK)) { 168 fputs("access denied - no login file\n", 169 stderr); 170 syslog(LOG_ERR, 171 "access denied for %s - no %s\n", 172 name, _PATH_LOGIN); 173 exit(5); 174 } 175 } 176 177 (void) fclose(fp); 178 return; 179 } 180 (void)fprintf(stderr, "SLIP access denied for %s\n", name); 181 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 182 exit(4); 183 /* NOTREACHED */ 184 } 185 186 char * 187 sigstr(s) 188 int s; 189 { 190 if (s > 0 && s < NSIG) 191 return(sys_signame[s]); 192 else { 193 static char buf[32]; 194 (void)sprintf(buf, "sig %d", s); 195 return(buf); 196 } 197 } 198 199 void 200 hup_handler(s) 201 int s; 202 { 203 char logoutfile[MAXPATHLEN]; 204 205 (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname); 206 if (access(logoutfile, R_OK|X_OK) != 0) 207 (void)strcpy(logoutfile, _PATH_LOGOUT); 208 if (access(logoutfile, R_OK|X_OK) == 0) { 209 char logincmd[2*MAXPATHLEN+32]; 210 211 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed, 212 loginargs); 213 (void) system(logincmd); 214 } 215 (void) close(0); 216 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 217 sigstr(s)); 218 exit(1); 219 /* NOTREACHED */ 220 } 221 222 main(argc, argv) 223 int argc; 224 char *argv[]; 225 { 226 int fd, s, ldisc, odisc; 227 char *name; 228 #ifdef POSIX 229 struct termios tios, otios; 230 #else 231 struct sgttyb tty, otty; 232 #endif 233 char logincmd[2*BUFSIZ+32]; 234 extern uid_t getuid(); 235 236 if ((name = strrchr(argv[0], '/')) == NULL) 237 name = argv[0]; 238 s = getdtablesize(); 239 for (fd = 3 ; fd < s ; fd++) 240 (void) close(fd); 241 openlog(name, LOG_PID, LOG_DAEMON); 242 uid = getuid(); 243 if (argc > 1) { 244 findid(argv[1]); 245 246 /* 247 * Disassociate from current controlling terminal, if any, 248 * and ensure that the slip line is our controlling terminal. 249 */ 250 #ifdef POSIX 251 if (fork() > 0) 252 exit(0); 253 if (setsid() < 0) 254 perror("setsid"); 255 #else 256 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) { 257 extern char *ttyname(); 258 259 (void) ioctl(fd, TIOCNOTTY, (caddr_t)0); 260 (void) close(fd); 261 /* open slip tty again to acquire as controlling tty? */ 262 fd = open(ttyname(0), O_RDWR, 0); 263 if (fd >= 0) 264 (void) close(fd); 265 } 266 (void) setpgrp(0, getpid()); 267 #endif 268 if (argc > 2) { 269 if ((fd = open(argv[2], O_RDWR)) == -1) { 270 perror(argv[2]); 271 exit(2); 272 } 273 (void) dup2(fd, 0); 274 if (fd > 2) 275 close(fd); 276 } 277 #ifdef TIOCSCTTY 278 if (ioctl(0, TIOCSCTTY, (caddr_t)0) != 0) 279 perror("ioctl (TIOCSCTTY)"); 280 #endif 281 } else { 282 extern char *getlogin(); 283 284 if ((name = getlogin()) == NULL) { 285 (void) fprintf(stderr, "access denied - no username\n"); 286 syslog(LOG_ERR, "access denied - getlogin returned 0\n"); 287 exit(1); 288 } 289 findid(name); 290 } 291 (void) fchmod(0, 0600); 292 (void) fprintf(stderr, "starting slip login for %s\n", loginname); 293 #ifdef POSIX 294 /* set up the line parameters */ 295 if (tcgetattr(0, &tios) < 0) { 296 syslog(LOG_ERR, "tcgetattr: %m"); 297 exit(1); 298 } 299 otios = tios; 300 cfmakeraw(&tios); 301 tios.c_iflag &= ~IMAXBEL; 302 if (tcsetattr(0, TCSAFLUSH, &tios) < 0) { 303 syslog(LOG_ERR, "tcsetattr: %m"); 304 exit(1); 305 } 306 speed = cfgetispeed(&tios); 307 #else 308 /* set up the line parameters */ 309 if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) { 310 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 311 exit(1); 312 } 313 otty = tty; 314 speed = tty.sg_ispeed; 315 tty.sg_flags = RAW | ANYP; 316 if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) { 317 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 318 exit(1); 319 } 320 #endif 321 /* find out what ldisc we started with */ 322 if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) { 323 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 324 exit(1); 325 } 326 ldisc = SLIPDISC; 327 if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) { 328 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 329 exit(1); 330 } 331 /* find out what unit number we were assigned */ 332 if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) { 333 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 334 exit(1); 335 } 336 (void) signal(SIGHUP, hup_handler); 337 (void) signal(SIGTERM, hup_handler); 338 339 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 340 (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed, 341 loginargs); 342 /* 343 * aim stdout and errout at /dev/null so logincmd output won't 344 * babble into the slip tty line. 345 */ 346 (void) close(1); 347 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 348 if (fd < 0) { 349 syslog(LOG_ERR, "open /dev/null: %m"); 350 exit(1); 351 } 352 (void) dup2(fd, 1); 353 (void) close(fd); 354 } 355 (void) dup2(1, 2); 356 357 /* 358 * Run login and logout scripts as root (real and effective); 359 * current route(8) is setuid root, and checks the real uid 360 * to see whether changes are allowed (or just "route get"). 361 */ 362 (void) setuid(0); 363 if (s = system(logincmd)) { 364 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 365 loginname, s, loginfile); 366 (void) ioctl(0, TIOCSETD, (caddr_t)&odisc); 367 exit(6); 368 } 369 if (ioctl(0, SLIOCSFLAGS, (caddr_t)&slip_mode) < 0) { 370 syslog(LOG_ERR, "ioctl (SLIOCSFLAGS): %m"); 371 exit(1); 372 } 373 374 /* twiddle thumbs until we get a signal */ 375 while (1) 376 sigpause(0); 377 378 /* NOTREACHED */ 379 } 380
Indexes created Thu Oct 23 22:10:10 GMT 2025