sliplogin.tproj/sliplogin.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*-
  25  * Copyright (c) 1990, 1993
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57 #ifndef lint
  58 static char copyright[] =
  59 "@(#) Copyright (c) 1990, 1993\n\
  60         The Regents of the University of California.  All rights reserved.\n";
  61 #endif /* not lint */
  62
  63 #ifndef lint
  64 static char sccsid[] = "@(#)sliplogin.c 8.2 (Berkeley) 2/1/94";
  65 #endif /* not lint */
  66
  67 /*
  68  * sliplogin.c
  69  * [MUST BE RUN SUID, SLOPEN DOES A SUSER()!]
  70  *
  71  * This program initializes its own tty port to be an async TCP/IP interface.
  72  * It sets the line discipline to slip, invokes a shell script to initialize
  73  * the network interface, then pauses forever waiting for hangup.
  74  *
  75  * It is a remote descendant of several similar programs with incestuous ties:
  76  * - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL.
  77  * - slattach, probably by Rick Adams but touched by countless hordes.
  78  * - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it.
  79  *
  80  * There are two forms of usage:
  81  *
  82  * "sliplogin"
  83  * Invoked simply as "sliplogin", the program looks up the username
  84  * in the file /etc/slip.hosts.
  85  * If an entry is found, the line on fd0 is configured for SLIP operation
  86  * as specified in the file.
  87  *
  88  * "sliplogin IPhostlogin </dev/ttyb"
  89  * Invoked by root with a username, the name is looked up in the
  90  * /etc/slip.hosts file and if found fd0 is configured as in case 1.
  91  */
  92
  93 #include <sys/param.h>
  94 #include <sys/socket.h>
  95 #include <sys/signal.h>
  96 #include <sys/file.h>
  97 #include <sys/syslog.h>
  98 #include <netdb.h>
  99
 100 #if BSD >= 199006
 101 #define POSIX
 102 #endif
 103 #ifdef POSIX
 104 #include <sys/termios.h>
 105 #include <sys/ioctl.h>
 106 #include <ttyent.h>
 107 #else
 108 #include <sgtty.h>
 109 #endif
 110 #include <net/slip.h>
 111
 112 #include <stdio.h>
 113 #include <errno.h>
 114 #include <ctype.h>
 115 #include <string.h>
 116 #include "pathnames.h"
 117
 118 int     unit;
 119 int     speed;
 120 int     uid;
 121 char    loginargs[BUFSIZ];
 122 char    loginfile[MAXPATHLEN];
 123 char    loginname[BUFSIZ];
 124
 125 void
 126 findid(name)
 127         char *name;
 128 {
 129         FILE *fp;
 130         static char slopt[5][16];
 131         static char laddr[16];
 132         static char raddr[16];
 133         static char mask[16];
 134         char user[16];
 135         int i, j, n;
 136
 137         (void)strcpy(loginname, name);
 138         if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) {
 139                 (void)fprintf(stderr, "sliplogin: %s: %s\n",
 140                     _PATH_ACCESS, strerror(errno));
 141                 syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS);
 142                 exit(1);
 143         }
 144         while (fgets(loginargs, sizeof(loginargs) - 1, fp)) {
 145                 if (ferror(fp))
 146                         break;
 147                 n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n",
 148                         user, laddr, raddr, mask, slopt[0], slopt[1],
 149                         slopt[2], slopt[3], slopt[4]);
 150                 if (user[0] == '#' || isspace(user[0]))
 151                         continue;
 152                 if (strcmp(user, name) != 0)
 153                         continue;
 154
 155                 /*
 156                  * we've found the guy we're looking for -- see if
 157                  * there's a login file we can use.  First check for
 158                  * one specific to this host.  If none found, try for
 159                  * a generic one.
 160                  */
 161                 (void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name);
 162                 if (access(loginfile, R_OK|X_OK) != 0) {
 163                         (void)strcpy(loginfile, _PATH_LOGIN);
 164                         if (access(loginfile, R_OK|X_OK)) {
 165                                 fputs("access denied - no login file\n",
 166                                       stderr);
 167                                 syslog(LOG_ERR,
 168                                        "access denied for %s - no %s\n",
 169                                        name, _PATH_LOGIN);
 170                                 exit(5);
 171                         }
 172                 }
 173
 174                 (void) fclose(fp);
 175                 return;
 176         }
 177         (void)fprintf(stderr, "SLIP access denied for %s\n", name);
 178         syslog(LOG_ERR, "SLIP access denied for %s\n", name);
 179         exit(4);
 180         /* NOTREACHED */
 181 }
 182
 183 char *
 184 sigstr(s)
 185         int s;
 186 {
 187         static char buf[32];
 188
 189         switch (s) {
 190         case SIGHUP:    return("HUP");
 191         case SIGINT:    return("INT");
 192         case SIGQUIT:   return("QUIT");
 193         case SIGILL:    return("ILL");
 194         case SIGTRAP:   return("TRAP");
 195         case SIGIOT:    return("IOT");
 196         case SIGEMT:    return("EMT");
 197         case SIGFPE:    return("FPE");
 198         case SIGKILL:   return("KILL");
 199         case SIGBUS:    return("BUS");
 200         case SIGSEGV:   return("SEGV");
 201         case SIGSYS:    return("SYS");
 202         case SIGPIPE:   return("PIPE");
 203         case SIGALRM:   return("ALRM");
 204         case SIGTERM:   return("TERM");
 205         case SIGURG:    return("URG");
 206         case SIGSTOP:   return("STOP");
 207         case SIGTSTP:   return("TSTP");
 208         case SIGCONT:   return("CONT");
 209         case SIGCHLD:   return("CHLD");
 210         case SIGTTIN:   return("TTIN");
 211         case SIGTTOU:   return("TTOU");
 212         case SIGIO:     return("IO");
 213         case SIGXCPU:   return("XCPU");
 214         case SIGXFSZ:   return("XFSZ");
 215         case SIGVTALRM: return("VTALRM");
 216         case SIGPROF:   return("PROF");
 217         case SIGWINCH:  return("WINCH");
 218 #ifdef SIGLOST
 219         case SIGLOST:   return("LOST");
 220 #endif
 221         case SIGUSR1:   return("USR1");
 222         case SIGUSR2:   return("USR2");
 223         }
 224         (void)sprintf(buf, "sig %d", s);
 225         return(buf);
 226 }
 227
 228 void
 229 hup_handler(s)
 230         int s;
 231 {
 232         char logoutfile[MAXPATHLEN];
 233
 234         (void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname);
 235         if (access(logoutfile, R_OK|X_OK) != 0)
 236                 (void)strcpy(logoutfile, _PATH_LOGOUT);
 237         if (access(logoutfile, R_OK|X_OK) == 0) {
 238                 char logincmd[2*MAXPATHLEN+32];
 239
 240                 (void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed,
 241                               loginargs);
 242                 (void) system(logincmd);
 243         }
 244         (void) close(0);
 245         syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit,
 246                sigstr(s));
 247         exit(1);
 248         /* NOTREACHED */
 249 }
 250
 251 main(argc, argv)
 252         int argc;
 253         char *argv[];
 254 {
 255         int fd, s, ldisc, odisc;
 256         char *name;
 257 #ifdef POSIX
 258         struct termios tios, otios;
 259 #else
 260         struct sgttyb tty, otty;
 261 #endif
 262         char logincmd[2*BUFSIZ+32];
 263         extern uid_t getuid();
 264
 265         if ((name = strrchr(argv[0], '/')) == NULL)
 266                 name = argv[0];
 267         s = getdtablesize();
 268         for (fd = 3 ; fd < s ; fd++)
 269                 (void) close(fd);
 270         openlog(name, LOG_PID, LOG_DAEMON);
 271         uid = getuid();
 272         if (argc > 1) {
 273                 findid(argv[1]);
 274
 275                 /*
 276                  * Disassociate from current controlling terminal, if any,
 277                  * and ensure that the slip line is our controlling terminal.
 278                  */
 279 #ifdef POSIX
 280                 if (fork() > 0)
 281                         exit(0);
 282                 if (setsid() != 0)
 283                         perror("setsid");
 284 #else
 285                 if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) {
 286                         extern char *ttyname();
 287
 288                         (void) ioctl(fd, TIOCNOTTY, (caddr_t)0);
 289                         (void) close(fd);
 290                         /* open slip tty again to acquire as controlling tty? */
 291                         fd = open(ttyname(0), O_RDWR, 0);
 292                         if (fd >= 0)
 293                                 (void) close(fd);
 294                 }
 295                 (void) setpgrp(0, getpid());
 296 #endif
 297                 if (argc > 2) {
 298                         if ((fd = open(argv[2], O_RDWR)) == -1) {
 299                                 perror(argv[2]);
 300                                 exit(2);
 301                         }
 302                         (void) dup2(fd, 0);
 303                         if (fd > 2)
 304                                 close(fd);
 305                 }
 306 #ifdef TIOCSCTTY
 307                 if (ioctl(0, TIOCSCTTY, (caddr_t)0) != 0)
 308                         perror("ioctl (TIOCSCTTY)");
 309 #endif
 310         } else {
 311                 extern char *getlogin();
 312
 313                 if ((name = getlogin()) == NULL) {
 314                         (void) fprintf(stderr, "access denied - no username\n");
 315                         syslog(LOG_ERR, "access denied - getlogin returned 0\n");
 316                         exit(1);
 317                 }
 318                 findid(name);
 319         }
 320         (void) fchmod(0, 0600);
 321         (void) fprintf(stderr, "starting slip login for %s\n", loginname);
 322 #ifdef POSIX
 323         /* set up the line parameters */
 324         if (tcgetattr(0, &tios) < 0) {
 325                 syslog(LOG_ERR, "tcgetattr: %m");
 326                 exit(1);
 327         }
 328         otios = tios;
 329         cfmakeraw(&tios);
 330         tios.c_iflag &= ~IMAXBEL;
 331         if (tcsetattr(0, TCSAFLUSH, &tios) < 0) {
 332                 syslog(LOG_ERR, "tcsetattr: %m");
 333                 exit(1);
 334         }
 335         speed = cfgetispeed(&tios);
 336 #else
 337         /* set up the line parameters */
 338         if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) {
 339                 syslog(LOG_ERR, "ioctl (TIOCGETP): %m");
 340                 exit(1);
 341         }
 342         otty = tty;
 343         speed = tty.sg_ispeed;
 344         tty.sg_flags = RAW | ANYP;
 345         if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) {
 346                 syslog(LOG_ERR, "ioctl (TIOCSETP): %m");
 347                 exit(1);
 348         }
 349 #endif
 350         /* find out what ldisc we started with */
 351         if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) {
 352                 syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m");
 353                 exit(1);
 354         }
 355         ldisc = SLIPDISC;
 356         if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) {
 357                 syslog(LOG_ERR, "ioctl(TIOCSETD): %m");
 358                 exit(1);
 359         }
 360         /* find out what unit number we were assigned */
 361         if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) {
 362                 syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m");
 363                 exit(1);
 364         }
 365         (void) signal(SIGHUP, hup_handler);
 366         (void) signal(SIGTERM, hup_handler);
 367
 368         syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname);
 369         (void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed,
 370                       loginargs);
 371         /*
 372          * aim stdout and errout at /dev/null so logincmd output won't
 373          * babble into the slip tty line.
 374          */
 375         (void) close(1);
 376         if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) {
 377                 if (fd < 0) {
 378                         syslog(LOG_ERR, "open /dev/null: %m");
 379                         exit(1);
 380                 }
 381                 (void) dup2(fd, 1);
 382                 (void) close(fd);
 383         }
 384         (void) dup2(1, 2);
 385
 386         /*
 387          * Run login and logout scripts as root (real and effective);
 388          * current route(8) is setuid root, and checks the real uid
 389          * to see whether changes are allowed (or just "route get").
 390          */
 391         (void) setuid(0);
 392         if (s = system(logincmd)) {
 393                 syslog(LOG_ERR, "%s login failed: exit status %d from %s",
 394                        loginname, s, loginfile);
 395                 (void) ioctl(0, TIOCSETD, (caddr_t)&odisc);
 396                 exit(6);
 397         }
 398
 399         /* twiddle thumbs until we get a signal */
 400         while (1)
 401                 sigpause(0);
 402
 403         /* NOTREACHED */
 404 }