5d2d59d9aa
2. set some seteuid calls to allow sliplogin to be run by users from the commandline in stead of from login inlo. Submitted by: guido
385 lines
10 KiB
C
385 lines
10 KiB
C
/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char copyright[] =
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"@(#) Copyright (c) 1990, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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static char sccsid[] = "@(#)sliplogin.c 8.2 (Berkeley) 2/1/94";
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#endif /* not lint */
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/*
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* sliplogin.c
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* [MUST BE RUN SUID, SLOPEN DOES A SUSER()!]
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*
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* This program initializes its own tty port to be an async TCP/IP interface.
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* It sets the line discipline to slip, invokes a shell script to initialize
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* the network interface, then pauses forever waiting for hangup.
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*
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* It is a remote descendant of several similar programs with incestuous ties:
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* - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL.
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* - slattach, probably by Rick Adams but touched by countless hordes.
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* - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it.
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*
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* There are two forms of usage:
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*
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* "sliplogin"
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* Invoked simply as "sliplogin", the program looks up the username
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* in the file /etc/slip.hosts.
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* If an entry is found, the line on fd0 is configured for SLIP operation
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* as specified in the file.
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*
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* "sliplogin IPhostlogin </dev/ttyb"
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* Invoked by root with a username, the name is looked up in the
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* /etc/slip.hosts file and if found fd0 is configured as in case 1.
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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/signal.h>
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#include <sys/file.h>
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#include <sys/syslog.h>
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#include <netdb.h>
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#if BSD >= 199006
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#define POSIX
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#endif
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#ifdef POSIX
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#include <sys/termios.h>
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#include <sys/ioctl.h>
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#include <ttyent.h>
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#else
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#include <sgtty.h>
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#endif
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#include <net/slip.h>
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#include <stdio.h>
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#include <errno.h>
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#include <ctype.h>
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#include <string.h>
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#include "pathnames.h"
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int unit;
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int speed;
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int uid;
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char loginargs[BUFSIZ];
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char loginfile[MAXPATHLEN];
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char loginname[BUFSIZ];
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void
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findid(name)
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char *name;
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{
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FILE *fp;
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static char slopt[5][16];
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static char laddr[16];
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static char raddr[16];
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static char mask[16];
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char user[16];
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int i, j, n;
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(void)strcpy(loginname, name);
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if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) {
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(void)fprintf(stderr, "sliplogin: %s: %s\n",
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_PATH_ACCESS, strerror(errno));
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syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS);
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exit(1);
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}
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while (fgets(loginargs, sizeof(loginargs) - 1, fp)) {
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if (ferror(fp))
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break;
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n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n",
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user, laddr, raddr, mask, slopt[0], slopt[1],
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slopt[2], slopt[3], slopt[4]);
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if (user[0] == '#' || isspace(user[0]))
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continue;
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if (strcmp(user, name) != 0)
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continue;
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/*
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* we've found the guy we're looking for -- see if
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* there's a login file we can use. First check for
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* one specific to this host. If none found, try for
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* a generic one.
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*/
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(void)sprintf(loginfile, "%s.%s", _PATH_LOGIN, name);
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if (access(loginfile, R_OK|X_OK) != 0) {
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(void)strcpy(loginfile, _PATH_LOGIN);
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if (access(loginfile, R_OK|X_OK)) {
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fputs("access denied - no login file\n",
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stderr);
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syslog(LOG_ERR,
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"access denied for %s - no %s\n",
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name, _PATH_LOGIN);
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exit(5);
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}
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}
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(void) fclose(fp);
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return;
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}
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(void)fprintf(stderr, "SLIP access denied for %s\n", name);
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syslog(LOG_ERR, "SLIP access denied for %s\n", name);
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exit(4);
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/* NOTREACHED */
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}
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char *
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sigstr(s)
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int s;
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{
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static char buf[32];
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switch (s) {
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case SIGHUP: return("HUP");
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case SIGINT: return("INT");
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case SIGQUIT: return("QUIT");
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case SIGILL: return("ILL");
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case SIGTRAP: return("TRAP");
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case SIGIOT: return("IOT");
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case SIGEMT: return("EMT");
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case SIGFPE: return("FPE");
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case SIGKILL: return("KILL");
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case SIGBUS: return("BUS");
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case SIGSEGV: return("SEGV");
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case SIGSYS: return("SYS");
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case SIGPIPE: return("PIPE");
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case SIGALRM: return("ALRM");
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case SIGTERM: return("TERM");
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case SIGURG: return("URG");
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case SIGSTOP: return("STOP");
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case SIGTSTP: return("TSTP");
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case SIGCONT: return("CONT");
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case SIGCHLD: return("CHLD");
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case SIGTTIN: return("TTIN");
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case SIGTTOU: return("TTOU");
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case SIGIO: return("IO");
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case SIGXCPU: return("XCPU");
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case SIGXFSZ: return("XFSZ");
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case SIGVTALRM: return("VTALRM");
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case SIGPROF: return("PROF");
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case SIGWINCH: return("WINCH");
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#ifdef SIGLOST
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case SIGLOST: return("LOST");
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#endif
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case SIGUSR1: return("USR1");
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case SIGUSR2: return("USR2");
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}
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(void)sprintf(buf, "sig %d", s);
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return(buf);
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}
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void
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hup_handler(s)
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int s;
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{
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char logoutfile[MAXPATHLEN];
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seteuid(0);
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(void)sprintf(logoutfile, "%s.%s", _PATH_LOGOUT, loginname);
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if (access(logoutfile, R_OK|X_OK) != 0)
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(void)strcpy(logoutfile, _PATH_LOGOUT);
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if (access(logoutfile, R_OK|X_OK) == 0) {
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char logincmd[2*MAXPATHLEN+32];
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(void) sprintf(logincmd, "%s %d %d %s", logoutfile, unit, speed,
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loginargs);
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(void) system(logincmd);
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}
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(void) close(0);
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syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit,
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sigstr(s));
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exit(1);
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/* NOTREACHED */
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}
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main(argc, argv)
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int argc;
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char *argv[];
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{
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int fd, s, ldisc, odisc;
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char *name;
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#ifdef POSIX
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struct termios tios, otios;
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#else
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struct sgttyb tty, otty;
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#endif
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char logincmd[2*BUFSIZ+32];
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extern uid_t getuid();
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if ((name = strrchr(argv[0], '/')) == NULL)
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name = argv[0];
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s = getdtablesize();
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for (fd = 3 ; fd < s ; fd++)
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(void) close(fd);
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openlog(name, LOG_PID, LOG_DAEMON);
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uid = getuid();
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if (argc > 1) {
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findid(argv[1]);
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/*
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* Disassociate from current controlling terminal, if any,
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* and ensure that the slip line is our controlling terminal.
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*/
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#ifdef POSIX
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if (fork() > 0)
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exit(0);
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if (setsid() == -1)
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perror("setsid");
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#else
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if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) {
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extern char *ttyname();
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(void) ioctl(fd, TIOCNOTTY, (caddr_t)0);
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(void) close(fd);
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/* open slip tty again to acquire as controlling tty? */
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fd = open(ttyname(0), O_RDWR, 0);
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if (fd >= 0)
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(void) close(fd);
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}
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(void) setpgrp(0, getpid());
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#endif
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if (argc > 2) {
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if ((fd = open(argv[2], O_RDWR)) == -1) {
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perror(argv[2]);
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exit(2);
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}
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(void) dup2(fd, 0);
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if (fd > 2)
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close(fd);
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}
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#ifdef TIOCSCTTY
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if (ioctl(0, TIOCSCTTY, (caddr_t)0) == -1)
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perror("ioctl (TIOCSCTTY)");
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#endif
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} else {
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extern char *getlogin();
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if ((name = getlogin()) == NULL) {
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(void) fprintf(stderr, "access denied - no username\n");
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syslog(LOG_ERR, "access denied - getlogin returned 0\n");
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exit(1);
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}
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findid(name);
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}
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(void) fchmod(0, 0600);
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(void) fprintf(stderr, "starting slip login for %s\n", loginname);
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#ifdef POSIX
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/* set up the line parameters */
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if (tcgetattr(0, &tios) < 0) {
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syslog(LOG_ERR, "tcgetattr: %m");
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exit(1);
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}
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otios = tios;
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cfmakeraw(&tios);
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tios.c_iflag &= ~IMAXBEL;
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if (tcsetattr(0, TCSAFLUSH, &tios) < 0) {
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syslog(LOG_ERR, "tcsetattr: %m");
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exit(1);
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}
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speed = cfgetispeed(&tios);
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#else
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/* set up the line parameters */
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if (ioctl(0, TIOCGETP, (caddr_t)&tty) < 0) {
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syslog(LOG_ERR, "ioctl (TIOCGETP): %m");
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exit(1);
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}
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otty = tty;
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speed = tty.sg_ispeed;
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tty.sg_flags = RAW | ANYP;
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if (ioctl(0, TIOCSETP, (caddr_t)&tty) < 0) {
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syslog(LOG_ERR, "ioctl (TIOCSETP): %m");
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exit(1);
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}
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#endif
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/* find out what ldisc we started with */
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if (ioctl(0, TIOCGETD, (caddr_t)&odisc) < 0) {
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syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m");
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exit(1);
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}
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ldisc = SLIPDISC;
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if (ioctl(0, TIOCSETD, (caddr_t)&ldisc) < 0) {
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syslog(LOG_ERR, "ioctl(TIOCSETD): %m");
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exit(1);
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}
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/* find out what unit number we were assigned */
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if (ioctl(0, SLIOCGUNIT, (caddr_t)&unit) < 0) {
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syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m");
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exit(1);
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}
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(void) signal(SIGHUP, hup_handler);
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(void) signal(SIGTERM, hup_handler);
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syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname);
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(void)sprintf(logincmd, "%s %d %d %s", loginfile, unit, speed,
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loginargs);
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/*
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* aim stdout and errout at /dev/null so logincmd output won't
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* babble into the slip tty line.
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*/
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(void) close(1);
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if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) {
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if (fd < 0) {
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syslog(LOG_ERR, "open /dev/null: %m");
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exit(1);
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}
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(void) dup2(fd, 1);
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(void) close(fd);
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}
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(void) dup2(1, 2);
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/*
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* Run login and logout scripts as root (real and effective);
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* current route(8) is setuid root, and checks the real uid
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* to see whether changes are allowed (or just "route get").
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*/
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(void) setuid(0);
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if (s = system(logincmd)) {
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syslog(LOG_ERR, "%s login failed: exit status %d from %s",
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loginname, s, loginfile);
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(void) ioctl(0, TIOCSETD, (caddr_t)&odisc);
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exit(6);
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}
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/* reset uid to users' to allow the user to give a signal. */
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seteuid(uid);
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/* twiddle thumbs until we get a signal */
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while (1)
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sigpause(0);
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/* NOTREACHED */
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}
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