xref: /freebsd/usr.bin/lock/lock.c (revision 50a93bedbd8714824de0922919e4d2d2c02ccc86)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1987, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Bob Toxen.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef lint
36 static const char copyright[] =
37 "@(#) Copyright (c) 1980, 1987, 1993\n\
38 	The Regents of the University of California.  All rights reserved.\n";
39 #endif /* not lint */
40 
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)lock.c	8.1 (Berkeley) 6/6/93";
44 #endif
45 #endif /* not lint */
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 /*
50  * Lock a terminal up until the given key is entered or the given
51  * interval times out.
52  *
53  * Timeout interval is by default TIMEOUT, it can be changed with
54  * an argument of the form -time where time is in minutes
55  */
56 
57 #include <sys/param.h>
58 #include <sys/stat.h>
59 #include <sys/signal.h>
60 #include <sys/consio.h>
61 
62 #include <err.h>
63 #include <ctype.h>
64 #include <errno.h>
65 #include <paths.h>
66 #include <pwd.h>
67 #include <stdint.h>
68 #include <stdio.h>
69 #include <stdlib.h>
70 #include <string.h>
71 #include <syslog.h>
72 #include <termios.h>
73 #include <time.h>
74 #include <unistd.h>
75 
76 #define	TIMEOUT	15
77 
78 static void quit(int);
79 static void bye(int);
80 static void hi(int);
81 static void usage(void);
82 
83 static struct timeval	timeout;
84 static struct timeval	zerotime;
85 static struct termios	tty, ntty;
86 static long		nexttime;		/* keep the timeout time */
87 static int		no_timeout;		/* lock terminal forever */
88 static int		vtyunlock;		/* Unlock flag and code. */
89 
90 /*ARGSUSED*/
91 int
92 main(int argc, char **argv)
93 {
94 	struct passwd *pw;
95 	struct itimerval ntimer, otimer;
96 	struct tm *timp;
97 	time_t timval;
98 	int ch, failures, sectimeout, usemine, vtylock;
99 	char *ap, *cryptpw, *mypw, *ttynam, *tzn;
100 	char hostname[MAXHOSTNAMELEN], s[BUFSIZ], s1[BUFSIZ];
101 
102 	openlog("lock", 0, LOG_AUTH);
103 
104 	sectimeout = TIMEOUT;
105 	pw = NULL;
106 	mypw = NULL;
107 	usemine = 0;
108 	no_timeout = 0;
109 	vtylock = 0;
110 	while ((ch = getopt(argc, argv, "npt:v")) != -1)
111 		switch((char)ch) {
112 		case 't':
113 			if ((sectimeout = atoi(optarg)) <= 0)
114 				errx(1, "illegal timeout value");
115 			break;
116 		case 'p':
117 			usemine = 1;
118 			if (!(pw = getpwuid(getuid())))
119 				errx(1, "unknown uid %d", getuid());
120 			mypw = strdup(pw->pw_passwd);
121 			break;
122 		case 'n':
123 			no_timeout = 1;
124 			break;
125 		case 'v':
126 			vtylock = 1;
127 			break;
128 		case '?':
129 		default:
130 			usage();
131 		}
132 	timeout.tv_sec = sectimeout * 60;
133 
134 	/* discard privs */
135 	if (setuid(getuid()) != 0)
136 		errx(1, "setuid failed");
137 
138 	if (tcgetattr(0, &tty))		/* get information for header */
139 		exit(1);
140 	gethostname(hostname, sizeof(hostname));
141 	if (!(ttynam = ttyname(0)))
142 		errx(1, "not a terminal?");
143 	if (strncmp(ttynam, _PATH_DEV, strlen(_PATH_DEV)) == 0)
144 		ttynam += strlen(_PATH_DEV);
145 	timval = time(NULL);
146 	nexttime = timval + (sectimeout * 60);
147 	timp = localtime(&timval);
148 	ap = asctime(timp);
149 	tzn = timp->tm_zone;
150 
151 	(void)signal(SIGINT, quit);
152 	(void)signal(SIGQUIT, quit);
153 	ntty = tty; ntty.c_lflag &= ~ECHO;
154 	(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &ntty);
155 
156 	if (!mypw) {
157 		/* get key and check again */
158 		(void)printf("Key: ");
159 		if (!fgets(s, sizeof(s), stdin) || *s == '\n')
160 			quit(0);
161 		(void)printf("\nAgain: ");
162 		/*
163 		 * Don't need EOF test here, if we get EOF, then s1 != s
164 		 * and the right things will happen.
165 		 */
166 		(void)fgets(s1, sizeof(s1), stdin);
167 		(void)putchar('\n');
168 		if (strcmp(s1, s)) {
169 			(void)printf("\07lock: passwords didn't match.\n");
170 			(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
171 			exit(1);
172 		}
173 		s[0] = '\0';
174 		mypw = s1;
175 	}
176 
177 	/* set signal handlers */
178 	(void)signal(SIGINT, hi);
179 	(void)signal(SIGQUIT, hi);
180 	(void)signal(SIGTSTP, hi);
181 	(void)signal(SIGALRM, bye);
182 
183 	ntimer.it_interval = zerotime;
184 	ntimer.it_value = timeout;
185 	if (!no_timeout)
186 		setitimer(ITIMER_REAL, &ntimer, &otimer);
187 	if (vtylock) {
188 		/*
189 		 * If this failed, we want to err out; warn isn't good
190 		 * enough, since we don't want the user to think that
191 		 * everything is nice and locked because they got a
192 		 * "Key:" prompt.
193 		 */
194 		if (ioctl(0, VT_LOCKSWITCH, &vtylock) == -1) {
195 			(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
196 			err(1, "locking vty");
197 		}
198 		vtyunlock = 0x2;
199 	}
200 
201 	/* header info */
202 	if (pw != NULL)
203 		(void)printf("lock: %s using %s on %s.", pw->pw_name,
204 		    ttynam, hostname);
205 	else
206 		(void)printf("lock: %s on %s.", ttynam, hostname);
207 	if (no_timeout)
208 		(void)printf(" no timeout.");
209 	else
210 		(void)printf(" timeout in %d minute%s.", sectimeout,
211 		    sectimeout != 1 ? "s" : "");
212 	if (vtylock)
213 		(void)printf(" vty locked.");
214 	(void)printf("\ntime now is %.20s%s%s", ap, tzn, ap + 19);
215 
216 	failures = 0;
217 
218 	for (;;) {
219 		(void)printf("Key: ");
220 		if (!fgets(s, sizeof(s), stdin)) {
221 			clearerr(stdin);
222 			hi(0);
223 			goto tryagain;
224 		}
225 		if (usemine) {
226 			s[strlen(s) - 1] = '\0';
227 			cryptpw = crypt(s, mypw);
228 			if (cryptpw != NULL && !strcmp(mypw, cryptpw))
229 				break;
230 		}
231 		else if (!strcmp(s, s1))
232 			break;
233 		(void)printf("\07\n");
234 	    	failures++;
235 		if (getuid() == 0)
236 	    	    syslog(LOG_NOTICE, "%d ROOT UNLOCK FAILURE%s (%s on %s)",
237 			failures, failures > 1 ? "S": "", ttynam, hostname);
238 tryagain:
239 		if (tcgetattr(0, &ntty) && (errno != EINTR))
240 			exit(1);
241 		sleep(1);		/* to discourage guessing */
242 	}
243 	if (getuid() == 0)
244 		syslog(LOG_NOTICE, "ROOT UNLOCK ON hostname %s port %s",
245 		    hostname, ttynam);
246 	quit(0);
247 	return(0); /* not reached */
248 }
249 
250 
251 static void
252 usage(void)
253 {
254 	(void)fprintf(stderr, "usage: lock [-npv] [-t timeout]\n");
255 	exit(1);
256 }
257 
258 static void
259 hi(int signo __unused)
260 {
261 	time_t timval;
262 
263 	timval = time(NULL);
264 	(void)printf("lock: type in the unlock key. ");
265 	if (no_timeout) {
266 		(void)putchar('\n');
267 	} else {
268 		(void)printf("timeout in %jd:%jd minutes\n",
269 		    (intmax_t)(nexttime - timval) / 60,
270 		    (intmax_t)(nexttime - timval) % 60);
271 	}
272 }
273 
274 static void
275 quit(int signo __unused)
276 {
277 	(void)putchar('\n');
278 	(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
279 	if (vtyunlock)
280 		(void)ioctl(0, VT_LOCKSWITCH, &vtyunlock);
281 	exit(0);
282 }
283 
284 static void
285 bye(int signo __unused)
286 {
287 	if (!no_timeout) {
288 		(void)tcsetattr(0, TCSADRAIN|TCSASOFT, &tty);
289 		if (vtyunlock)
290 			(void)ioctl(0, VT_LOCKSWITCH, &vtyunlock);
291 		(void)printf("lock: timeout\n");
292 		exit(1);
293 	}
294 }
295