lock.c revision 1.30 
1/*	$NetBSD: lock.c,v 1.30 2008/07/21 14:19:23 lukem Exp $	*/
2
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#include <sys/cdefs.h>
36#ifndef lint
37__COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1993\
38 The Regents of the University of California.  All rights reserved.");
39#endif /* not lint */
40
41#ifndef lint
42#if 0
43static char sccsid[] = "@(#)lock.c	8.1 (Berkeley) 6/6/93";
44#endif
45__RCSID("$NetBSD: lock.c,v 1.30 2008/07/21 14:19:23 lukem Exp $");
46#endif /* not lint */
47
48/*
49 * Lock a terminal up until the given key is entered, until the root
50 * password is entered, or the given interval times out.
51 *
52 * Timeout interval is by default TIMEOUT, it can be changed with
53 * an argument of the form -time where time is in minutes
54 */
55
56#include <sys/param.h>
57#include <sys/stat.h>
58#include <sys/time.h>
59#include <signal.h>
60
61#include <err.h>
62#include <pwd.h>
63#include <errno.h>
64#include <stdio.h>
65#include <stdlib.h>
66#include <string.h>
67#include <termios.h>
68#include <time.h>
69#include <unistd.h>
70
71#ifdef USE_PAM
72#include <security/pam_appl.h>
73#include <security/openpam.h>	/* for openpam_ttyconv() */
74#endif
75
76#ifdef SKEY
77#include <skey.h>
78#endif
79
80
81#define	TIMEOUT	15
82
83int	main(int, char **);
84
85static void	bye(int) __dead;
86static void	hi(int);
87static void	quit(int) __dead;
88#ifdef SKEY
89static int	skey_auth(const char *);
90#endif
91
92static struct timeval	timeout;
93static struct timeval	zerotime;
94static struct termios	tty, ntty;
95static int	notimeout;			/* no timeout at all */
96static long	nexttime;			/* keep the timeout time */
97
98int
99main(int argc, char **argv)
100{
101	struct passwd *pw;
102	struct timeval timval;
103	struct itimerval ntimer, otimer;
104	struct tm *timp;
105	time_t curtime;
106	int ch, usemine;
107	long sectimeout;
108	char *ap, *mypw, *ttynam;
109	const char *tzn;
110	uid_t uid = getuid();
111	char hostname[MAXHOSTNAMELEN + 1], s[BUFSIZ], s1[BUFSIZ];
112#ifdef USE_PAM
113	pam_handle_t *pamh = NULL;
114	static const struct pam_conv pamc = { &openpam_ttyconv, NULL };
115	int pam_err;
116#endif
117
118	if ((pw = getpwuid(getuid())) == NULL)
119		errx(1, "unknown uid %lu.", (u_long)uid);
120
121	notimeout = 0;
122	sectimeout = TIMEOUT;
123	mypw = NULL;
124	usemine = 0;
125
126	while ((ch = getopt(argc, argv, "npt:")) != -1)
127		switch ((char)ch) {
128		case 'n':
129			notimeout = 1;
130			break;
131		case 't':
132			errno = 0;
133			if (((sectimeout = strtol(optarg, &ap, 0)) == LONG_MAX
134			    || sectimeout == LONG_MIN)
135			    && errno == ERANGE)
136				err(1, "illegal timeout value: %s", optarg);
137			if (optarg == ap || *ap || sectimeout <= 0)
138				errx(1, "illegal timeout value: %s", optarg);
139			if (sectimeout >= INT_MAX / 60)
140				errx(1, "too large timeout value: %ld",
141				    sectimeout);
142			break;
143		case 'p':
144			usemine = 1;
145#ifndef USE_PAM
146			mypw = strdup(pw->pw_passwd);
147			if (!mypw)
148				err(1, "strdup");
149#endif
150			break;
151		case '?':
152		default:
153			(void)fprintf(stderr,
154			    "usage: %s [-np] [-t timeout]\n", getprogname());
155			exit(1);
156		}
157
158#if defined(USE_PAM) || defined(SKEY)
159	if (! usemine) {	/* -p with PAM or S/key needs privs */
160#endif
161	if (setuid(uid) == -1)	/* discard privs */
162		err(1, "setuid failed");
163#if defined(USE_PAM) || defined(SKEY)
164	}
165#endif
166
167	timeout.tv_sec = (int)sectimeout * 60;
168
169	if (tcgetattr(STDIN_FILENO, &tty) < 0)	/* get information for header */
170		err(1, "tcgetattr failed");
171	gethostname(hostname, sizeof(hostname));
172	hostname[sizeof(hostname) - 1] = '\0';
173	if (!(ttynam = ttyname(STDIN_FILENO)))
174		err(1, "ttyname failed");
175	if (gettimeofday(&timval, NULL) == -1)
176		err(1, "gettimeofday failed");
177	curtime = timval.tv_sec;
178	nexttime = timval.tv_sec + ((int)sectimeout * 60);
179	timp = localtime(&curtime);
180	ap = asctime(timp);
181#ifdef __SVR4
182	tzn = tzname[0];
183#else
184	tzn = timp->tm_zone;
185#endif
186
187	if (signal(SIGINT, quit) == SIG_ERR)
188		err(1, "signal failed");
189	if (signal(SIGQUIT, quit) == SIG_ERR)
190		err(1, "signal failed");
191	ntty = tty; ntty.c_lflag &= ~ECHO;
192	if (tcsetattr(STDIN_FILENO, TCSADRAIN, &ntty) == -1)
193		err(1, "tcsetattr");
194
195	if (!usemine) {
196		/* get key and check again */
197		(void)printf("Key: ");
198		if (!fgets(s, sizeof(s), stdin) || *s == '\n')
199			quit(0);
200		(void)printf("\nAgain: ");
201		/*
202		 * Don't need EOF test here, if we get EOF, then s1 != s
203		 * and the right things will happen.
204		 */
205		(void)fgets(s1, sizeof(s1), stdin);
206		(void)putchar('\n');
207		if (strcmp(s1, s)) {
208			(void)printf("\alock: passwords didn't match.\n");
209			(void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
210			exit(1);
211		}
212		s[0] = '\0';
213		mypw = s1;
214	}
215#ifdef USE_PAM
216	if (usemine) {
217		pam_err = pam_start("lock", pw->pw_name, &pamc, &pamh);
218		if (pam_err != PAM_SUCCESS)
219			err(1, "pam_start: %s", pam_strerror(NULL, pam_err));
220	}
221#endif
222
223	/* set signal handlers */
224	if (signal(SIGINT, hi) == SIG_ERR)
225		err(1, "signal failed");
226	if (signal(SIGQUIT, hi) == SIG_ERR)
227		err(1, "signal failed");
228	if (signal(SIGTSTP, hi) == SIG_ERR)
229		err(1, "signal failed");
230
231	if (notimeout) {
232		if (signal(SIGALRM, hi) == SIG_ERR)
233			err(1, "signal failed");
234		(void)printf("lock: %s on %s.  no timeout.\n"
235		    "time now is %.20s%s%s",
236		    ttynam, hostname, ap, tzn, ap + 19);
237	}
238	else {
239		if (signal(SIGALRM, bye) == SIG_ERR)
240			err(1, "signal failed");
241
242		ntimer.it_interval = zerotime;
243		ntimer.it_value = timeout;
244		if (setitimer(ITIMER_REAL, &ntimer, &otimer) == -1)
245			err(1, "setitimer failed");
246
247		/* header info */
248		(void)printf("lock: %s on %s. timeout in %ld minutes\n"
249		    "time now is %.20s%s%s",
250		    ttynam, hostname, sectimeout, ap, tzn, ap + 19);
251	}
252
253	for (;;) {
254#ifdef USE_PAM
255		if (usemine) {
256			pam_err = pam_authenticate(pamh, 0);
257			if (pam_err == PAM_SUCCESS)
258				break;
259			goto tryagain;
260		}
261#endif
262		(void)printf("Key: ");
263		if (!fgets(s, sizeof(s), stdin)) {
264			clearerr(stdin);
265			hi(0);
266			goto tryagain;
267		}
268#ifndef USE_PAM
269		if (usemine) {
270			s[strlen(s) - 1] = '\0';
271#ifdef SKEY
272			if (strcasecmp(s, "s/key") == 0) {
273				if (skey_auth(pw->pw_name))
274					break;
275			}
276#endif
277			if (!strcmp(mypw, crypt(s, mypw)))
278				break;
279		}
280		else
281#endif
282			if (!strcmp(s, s1))
283				break;
284		(void)printf("\a\n");
285 tryagain:
286		if (tcsetattr(STDIN_FILENO, TCSADRAIN, &ntty) == -1
287		    && errno != EINTR)
288			err(1, "tcsetattr failed");
289	}
290#ifdef USE_PAM
291	if (usemine) {
292		(void)pam_end(pamh, pam_err);
293	}
294#endif
295	quit(0);
296	/* NOTREACHED */
297	return 0;
298}
299
300#ifdef SKEY
301/*
302 * We can't use libskey's skey_authenticate() since it
303 * handles signals in a way that's inappropriate
304 * for our needs. Instead we roll our own.
305 */
306static int
307skey_auth(const char *user)
308{
309	char s[128];
310	const char *ask;
311	int ret = 0;
312
313	if (!skey_haskey(user) && (ask = skey_keyinfo(user))) {
314		(void)printf("\n[%s]\nResponse: ", ask);
315		if (!fgets(s, sizeof(s), stdin) || *s == '\n')
316			clearerr(stdin);
317		else {
318			s[strlen(s) - 1] = '\0';
319			if (skey_passcheck(user, s) != -1)
320				ret = 1;
321		}
322	} else
323		(void)printf("Sorry, you have no s/key.\n");
324	return ret;
325}
326#endif
327
328static void
329hi(dummy)
330	int dummy;
331{
332	struct timeval timval;
333
334	if (notimeout)
335		(void)printf("lock: type in the unlock key.\n");
336	else {
337		if (gettimeofday(&timval, NULL) == -1)
338			err(1, "gettimeofday failed");
339		(void)printf("lock: type in the unlock key. "
340		    "timeout in %ld:%ld minutes\n",
341		    (nexttime - timval.tv_sec) / 60,
342		    (nexttime - timval.tv_sec) % 60);
343	}
344}
345
346static void
347quit(int dummy)
348{
349	(void)putchar('\n');
350	(void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
351	exit(0);
352}
353
354static void
355bye(int dummy)
356{
357	(void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
358	(void)printf("lock: timeout\n");
359	exit(1);
360}
361