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54ca359425
1. If fgets fails, don't go into an infinite cpu-intensive loop. Instead, check to see if the terminal still exists, and sleep(1) otherwise. 2. When we check to see if the terminal still exists, make sure we're not mislead by EINTR. This could have been a security issue, but fortunately the current implementation of tcgetattr doesn't EINTR. PR: bin/60758 Approved by: rwatson (mentor)
288 lines
7.4 KiB
C
288 lines
7.4 KiB
C
/*
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* Copyright (c) 1980, 1987, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Bob Toxen.
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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 const char copyright[] =
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"@(#) Copyright (c) 1980, 1987, 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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#if 0
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static char sccsid[] = "@(#)lock.c 8.1 (Berkeley) 6/6/93";
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#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Lock a terminal up until the given key is entered or the given
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* interval times out.
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*
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* Timeout interval is by default TIMEOUT, it can be changed with
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* an argument of the form -time where time is in minutes
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*/
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/signal.h>
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#include <sys/consio.h>
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#include <err.h>
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#include <ctype.h>
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#include <errno.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <termios.h>
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#include <unistd.h>
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#define TIMEOUT 15
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void quit(int);
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void bye(int);
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void hi(int);
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static void usage(void);
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struct timeval timeout;
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struct timeval zerotime;
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struct termios tty, ntty;
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long nexttime; /* keep the timeout time */
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int no_timeout; /* lock terminal forever */
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int vtyunlock; /* Unlock flag and code. */
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/*ARGSUSED*/
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int
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main(int argc, char **argv)
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{
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struct passwd *pw;
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struct timeval timval;
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time_t timval_sec;
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struct itimerval ntimer, otimer;
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struct tm *timp;
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int ch, failures, sectimeout, usemine, vtylock;
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char *ap, *mypw, *ttynam, *tzn;
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char hostname[MAXHOSTNAMELEN], s[BUFSIZ], s1[BUFSIZ];
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openlog("lock", LOG_ODELAY, LOG_AUTH);
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sectimeout = TIMEOUT;
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mypw = NULL;
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usemine = 0;
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no_timeout = 0;
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vtylock = 0;
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while ((ch = getopt(argc, argv, "npt:v")) != -1)
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switch((char)ch) {
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case 't':
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if ((sectimeout = atoi(optarg)) <= 0)
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errx(1, "illegal timeout value");
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break;
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case 'p':
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usemine = 1;
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if (!(pw = getpwuid(getuid())))
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errx(1, "unknown uid %d", getuid());
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mypw = strdup(pw->pw_passwd);
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break;
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case 'n':
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no_timeout = 1;
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break;
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case 'v':
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vtylock = 1;
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break;
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case '?':
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default:
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usage();
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}
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timeout.tv_sec = sectimeout * 60;
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setuid(getuid()); /* discard privs */
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if (tcgetattr(0, &tty)) /* get information for header */
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exit(1);
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gethostname(hostname, sizeof(hostname));
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if (!(ttynam = ttyname(0)))
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errx(1, "not a terminal?");
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if (gettimeofday(&timval, (struct timezone *)NULL))
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err(1, "gettimeofday");
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nexttime = timval.tv_sec + (sectimeout * 60);
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timval_sec = timval.tv_sec;
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timp = localtime(&timval_sec);
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ap = asctime(timp);
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tzn = timp->tm_zone;
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(void)signal(SIGINT, quit);
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(void)signal(SIGQUIT, quit);
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ntty = tty; ntty.c_lflag &= ~ECHO;
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(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &ntty);
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if (!mypw) {
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/* get key and check again */
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(void)printf("Key: ");
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if (!fgets(s, sizeof(s), stdin) || *s == '\n')
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quit(0);
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(void)printf("\nAgain: ");
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/*
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* Don't need EOF test here, if we get EOF, then s1 != s
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* and the right things will happen.
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*/
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(void)fgets(s1, sizeof(s1), stdin);
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(void)putchar('\n');
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if (strcmp(s1, s)) {
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(void)printf("\07lock: passwords didn't match.\n");
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(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
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exit(1);
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}
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s[0] = '\0';
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mypw = s1;
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}
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/* set signal handlers */
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(void)signal(SIGINT, hi);
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(void)signal(SIGQUIT, hi);
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(void)signal(SIGTSTP, hi);
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(void)signal(SIGALRM, bye);
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ntimer.it_interval = zerotime;
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ntimer.it_value = timeout;
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if (!no_timeout)
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setitimer(ITIMER_REAL, &ntimer, &otimer);
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if (vtylock) {
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/*
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* If this failed, we want to err out; warn isn't good
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* enough, since we don't want the user to think that
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* everything is nice and locked because they got a
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* "Key:" prompt.
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*/
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if (ioctl(0, VT_LOCKSWITCH, &vtylock) == -1) {
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(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
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err(1, "locking vty");
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}
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vtyunlock = 0x2;
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}
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/* header info */
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(void)printf("lock: %s on %s.", ttynam, hostname);
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if (no_timeout)
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(void)printf(" no timeout.");
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else
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(void)printf(" timeout in %d minute%s.", sectimeout,
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sectimeout != 1 ? "s" : "");
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if (vtylock)
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(void)printf(" vty locked.");
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(void)printf("\ntime now is %.20s%s%s", ap, tzn, ap + 19);
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failures = 0;
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for (;;) {
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(void)printf("Key: ");
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if (!fgets(s, sizeof(s), stdin)) {
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clearerr(stdin);
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hi(0);
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goto tryagain;
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}
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if (usemine) {
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s[strlen(s) - 1] = '\0';
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if (!strcmp(mypw, crypt(s, mypw)))
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break;
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}
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else if (!strcmp(s, s1))
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break;
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(void)printf("\07\n");
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failures++;
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if (getuid() == 0)
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syslog(LOG_NOTICE, "%d ROOT UNLOCK FAILURE%s (%s on %s)",
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failures, failures > 1 ? "S": "", ttynam, hostname);
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tryagain:
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if (tcgetattr(0, &ntty) && (errno != EINTR))
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exit(1);
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sleep(1); /* to discourage guessing */
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}
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if (getuid() == 0)
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syslog(LOG_NOTICE, "ROOT UNLOCK ON hostname %s port %s",
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hostname, ttynam);
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quit(0);
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return(0); /* not reached */
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}
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static void
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usage(void)
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{
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(void)fprintf(stderr, "usage: lock [-npv] [-t timeout]\n");
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exit(1);
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}
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void
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hi(int signo __unused)
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{
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struct timeval timval;
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if (!gettimeofday(&timval, (struct timezone *)NULL)) {
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(void)printf("lock: type in the unlock key. ");
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if (no_timeout) {
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(void)putchar('\n');
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} else {
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(void)printf("timeout in %ld:%ld minutes\n",
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(nexttime - timval.tv_sec) / 60,
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(nexttime - timval.tv_sec) % 60);
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}
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}
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}
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void
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quit(int signo __unused)
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{
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(void)putchar('\n');
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(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
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if (vtyunlock)
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(void)ioctl(0, VT_LOCKSWITCH, &vtyunlock);
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exit(0);
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}
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void
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bye(int signo __unused)
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{
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if (!no_timeout) {
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(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
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if (vtyunlock)
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(void)ioctl(0, VT_LOCKSWITCH, &vtyunlock);
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(void)printf("lock: timeout\n");
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exit(1);
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}
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}
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