sliplogin.c revision 1.21
1 /* $NetBSD: sliplogin.c,v 1.21 2004/10/30 15:44:04 dsl 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 __COPYRIGHT("@(#) Copyright (c) 1990, 1993\n\ 35 The Regents of the University of California. All rights reserved.\n"); 36 #endif /* not lint */ 37 38 #ifndef lint 39 #if 0 40 static char sccsid[] = "@(#)sliplogin.c 8.2 (Berkeley) 2/1/94"; 41 #else 42 __RCSID("$NetBSD: sliplogin.c,v 1.21 2004/10/30 15:44:04 dsl Exp $"); 43 #endif 44 #endif /* not lint */ 45 46 /* 47 * sliplogin.c 48 * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!] 49 * 50 * This program initializes its own tty port to be an async TCP/IP interface. 51 * It sets the line discipline to slip, invokes a shell script to initialize 52 * the network interface, then pauses forever waiting for hangup. 53 * 54 * It is a remote descendant of several similar programs with incestuous ties: 55 * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL. 56 * - slattach, probably by Rick Adams but touched by countless hordes. 57 * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it. 58 * 59 * There are two forms of usage: 60 * 61 * "sliplogin" 62 * Invoked simply as "sliplogin", the program looks up the username 63 * in the file /etc/slip.hosts. 64 * If an entry is found, the line on fd0 is configured for SLIP operation 65 * as specified in the file. 66 * 67 * "sliplogin IPhostlogin </dev/ttyb" 68 * Invoked by root with a username, the name is looked up in the 69 * /etc/slip.hosts file and if found fd0 is configured as in case 1. 70 */ 71 72 #include <sys/types.h> 73 #include <sys/file.h> 74 #include <sys/param.h> 75 #include <sys/socket.h> 76 #include <sys/stat.h> 77 #include <sys/syslog.h> 78 79 #if BSD >= 199006 80 #define POSIX 81 #endif 82 #ifdef POSIX 83 #include <termios.h> 84 #include <sys/ioctl.h> 85 #include <ttyent.h> 86 #else 87 #include <sgtty.h> 88 #endif 89 #include <net/slip.h> 90 91 #include <ctype.h> 92 #include <err.h> 93 #include <errno.h> 94 #include <netdb.h> 95 #include <signal.h> 96 #include <stdio.h> 97 #include <stdlib.h> 98 #include <string.h> 99 #include <unistd.h> 100 101 #include "pathnames.h" 102 103 int unit; 104 int speed; 105 int uid; 106 char loginargs[BUFSIZ]; 107 char loginfile[MAXPATHLEN]; 108 char loginname[BUFSIZ]; 109 110 void findid __P((char *)); 111 void hup_handler __P((int)); 112 int main __P((int, char **)); 113 const char *sigstr __P((int)); 114 115 void 116 findid(name) 117 char *name; 118 { 119 FILE *fp; 120 static char slopt[5][16]; 121 static char laddr[16]; 122 static char raddr[16]; 123 static char mask[16]; 124 char user[16]; 125 int n; 126 127 (void)strlcpy(loginname, name, sizeof(loginname)); 128 if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) { 129 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS); 130 err(1, "%s", _PATH_ACCESS); 131 } 132 while (fgets(loginargs, sizeof(loginargs) - 1, fp)) { 133 if (ferror(fp)) 134 break; 135 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n", 136 user, laddr, raddr, mask, slopt[0], slopt[1], 137 slopt[2], slopt[3], slopt[4]); 138 if (user[0] == '#' || isspace((unsigned char)user[0])) 139 continue; 140 if (strcmp(user, name) != 0) 141 continue; 142 143 /* 144 * we've found the guy we're looking for -- see if 145 * there's a login file we can use. First check for 146 * one specific to this host. If none found, try for 147 * a generic one. 148 */ 149 (void)snprintf(loginfile, sizeof loginfile, "%s.%s", 150 _PATH_LOGIN, name); 151 if (access(loginfile, R_OK|X_OK) != 0) { 152 (void)strlcpy(loginfile, _PATH_LOGIN, sizeof(loginfile)); 153 if (access(loginfile, R_OK|X_OK)) { 154 fputs("access denied - no login file\n", 155 stderr); 156 syslog(LOG_ERR, 157 "access denied for %s - no %s\n", 158 name, _PATH_LOGIN); 159 exit(5); 160 } 161 } 162 163 (void)fclose(fp); 164 return; 165 } 166 syslog(LOG_ERR, "SLIP access denied for %s\n", name); 167 errx(1, "SLIP access denied for %s", name); 168 /* NOTREACHED */ 169 } 170 171 const char * 172 sigstr(s) 173 int s; 174 { 175 176 if (s > 0 && s < NSIG) 177 return (sys_signame[s]); 178 else { 179 static char buf[32]; 180 181 (void)snprintf(buf, sizeof buf, "sig %d", s); 182 return (buf); 183 } 184 } 185 186 void 187 hup_handler(s) 188 int s; 189 { 190 char logoutfile[MAXPATHLEN]; 191 192 (void)snprintf(logoutfile, sizeof logoutfile, "%s.%s", _PATH_LOGOUT, 193 loginname); 194 if (access(logoutfile, R_OK|X_OK) != 0) 195 (void)strlcpy(logoutfile, _PATH_LOGOUT, sizeof(logoutfile)); 196 if (access(logoutfile, R_OK|X_OK) == 0) { 197 char logincmd[2*MAXPATHLEN+32]; 198 199 (void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", 200 logoutfile, unit, speed, loginargs); 201 (void)system(logincmd); 202 } 203 (void)close(0); 204 syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit, 205 sigstr(s)); 206 exit(1); 207 /* NOTREACHED */ 208 } 209 210 int 211 main(argc, argv) 212 int argc; 213 char *argv[]; 214 { 215 int fd, s, ldisc, odisc; 216 char *name; 217 #ifdef POSIX 218 struct termios tios, otios; 219 #else 220 struct sgttyb tty, otty; 221 #endif 222 char logincmd[2*BUFSIZ+32]; 223 224 if (strlen(argv[0]) > MAXLOGNAME) 225 errx(1, "login %s too long", argv[0]); 226 if ((name = strrchr(argv[0], '/')) == NULL) 227 name = argv[0]; 228 else 229 name++; 230 s = getdtablesize(); 231 for (fd = 3 ; fd < s ; fd++) 232 (void)close(fd); 233 openlog(name, LOG_PID, LOG_DAEMON); 234 uid = getuid(); 235 if (argc > 1) { 236 findid(argv[1]); 237 238 /* 239 * Disassociate from current controlling terminal, if any, 240 * and ensure that the slip line is our controlling terminal. 241 */ 242 #ifdef POSIX 243 switch (fork()) { 244 case -1: 245 perror("fork"); 246 syslog(LOG_ERR, "could not fork: %m"); 247 exit(1); 248 case 0: 249 break; 250 default: 251 exit(0); 252 } 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(STDIN_FILENO, TIOCSCTTY, (caddr_t)0) != 0) 279 perror("ioctl (TIOCSCTTY)"); 280 #endif 281 } else { 282 if ((name = getlogin()) == NULL) { 283 syslog(LOG_ERR, 284 "access denied - getlogin returned 0\n"); 285 errx(1, "access denied - no username"); 286 } 287 findid(name); 288 } 289 if (!isatty(STDIN_FILENO)) { 290 syslog(LOG_ERR, "stdin not a tty"); 291 errx(1, "stdin not a tty"); 292 } 293 (void)fchmod(STDIN_FILENO, 0600); 294 warnx("starting slip login for %s", loginname); 295 #ifdef POSIX 296 /* set up the line parameters */ 297 if (tcgetattr(STDIN_FILENO, &tios) < 0) { 298 syslog(LOG_ERR, "tcgetattr: %m"); 299 exit(1); 300 } 301 otios = tios; 302 cfmakeraw(&tios); 303 tios.c_iflag &= ~IMAXBEL; 304 if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tios) < 0) { 305 syslog(LOG_ERR, "tcsetattr: %m"); 306 exit(1); 307 } 308 speed = cfgetispeed(&tios); 309 #else 310 /* set up the line parameters */ 311 if (ioctl(STDIN_FILENO, TIOCGETP, (caddr_t)&tty) < 0) { 312 syslog(LOG_ERR, "ioctl (TIOCGETP): %m"); 313 exit(1); 314 } 315 otty = tty; 316 speed = tty.sg_ispeed; 317 tty.sg_flags = RAW | ANYP; 318 if (ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&tty) < 0) { 319 syslog(LOG_ERR, "ioctl (TIOCSETP): %m"); 320 exit(1); 321 } 322 #endif 323 /* find out what ldisc we started with */ 324 if (ioctl(STDIN_FILENO, TIOCGETD, (caddr_t)&odisc) < 0) { 325 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m"); 326 exit(1); 327 } 328 ldisc = SLIPDISC; 329 if (ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&ldisc) < 0) { 330 syslog(LOG_ERR, "ioctl(TIOCSETD): %m"); 331 exit(1); 332 } 333 /* find out what unit number we were assigned */ 334 if (ioctl(STDIN_FILENO, SLIOCGUNIT, (caddr_t)&unit) < 0) { 335 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m"); 336 exit(1); 337 } 338 (void)signal(SIGHUP, hup_handler); 339 (void)signal(SIGTERM, hup_handler); 340 341 syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname); 342 (void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", loginfile, 343 unit, speed, loginargs); 344 /* 345 * aim stdout and errout at /dev/null so logincmd output won't 346 * babble into the slip tty line. 347 */ 348 (void)close(1); 349 if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) { 350 if (fd < 0) { 351 syslog(LOG_ERR, "open /dev/null: %m"); 352 exit(1); 353 } 354 (void)dup2(fd, 1); 355 (void)close(fd); 356 } 357 (void)dup2(1, 2); 358 359 /* 360 * Run login and logout scripts as root (real and effective); 361 * current route(8) is setuid root, and checks the real uid 362 * to see whether changes are allowed (or just "route get"). 363 */ 364 (void)setuid(0); 365 if ((s = system(logincmd)) != 0) { 366 syslog(LOG_ERR, "%s login failed: exit status %d from %s", 367 loginname, s, loginfile); 368 (void)ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&odisc); 369 #ifdef POSIX 370 (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &otios); 371 #else 372 (void)ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&otty); 373 #endif 374 exit(6); 375 } 376 377 /* twiddle thumbs until we get a signal */ 378 while (1) 379 sigpause(0); 380 381 /* NOTREACHED */ 382 } 383
Indexes created Mon Sep 29 03:10:08 GMT 2025