login.c revision 7800 
1/*-
2 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static char copyright[] =
36"@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41static char sccsid[] = "@(#)login.c	8.4 (Berkeley) 4/2/94";
42#endif /* not lint */
43
44/*
45 * login [ name ]
46 * login -h hostname	(for telnetd, etc.)
47 * login -f name	(for pre-authenticated login: datakit, xterm, etc.)
48 */
49
50#include <sys/param.h>
51#include <sys/stat.h>
52#include <sys/time.h>
53#include <sys/resource.h>
54#include <sys/file.h>
55
56#include <err.h>
57#include <errno.h>
58#include <grp.h>
59#include <pwd.h>
60#include <setjmp.h>
61#include <signal.h>
62#include <stdio.h>
63#include <stdlib.h>
64#include <string.h>
65#include <syslog.h>
66#include <ttyent.h>
67#include <tzfile.h>
68#include <unistd.h>
69#include <utmp.h>
70
71#ifdef	SKEY
72#include <skey.h>
73#endif
74
75#include "pathnames.h"
76
77void	 badlogin __P((char *));
78void	 checknologin __P((void));
79void	 dolastlog __P((int));
80void	 getloginname __P((void));
81void	 motd __P((void));
82int	 rootterm __P((char *));
83void	 sigint __P((int));
84void	 sleepexit __P((int));
85char	*stypeof __P((char *));
86void	 timedout __P((int));
87void     login_fbtab __P((char *, uid_t, gid_t));
88#ifdef KERBEROS
89int	 klogin __P((struct passwd *, char *, char *, char *));
90#endif
91
92extern void login __P((struct utmp *));
93
94#define	TTYGRPNAME	"tty"		/* name of group to own ttys */
95
96/*
97 * This bounds the time given to login.  Not a define so it can
98 * be patched on machines where it's too small.
99 */
100u_int	timeout = 300;
101
102#ifdef KERBEROS
103int	notickets = 1;
104int	noticketsdontcomplain = 1;
105char	*instance;
106char	*krbtkfile_env;
107int	authok;
108#endif
109
110struct	passwd *pwd;
111int	failures;
112char	term[64], *envinit[1], *hostname, *username, *tty;
113
114int
115main(argc, argv)
116	int argc;
117	char *argv[];
118{
119	extern char **environ;
120	struct group *gr;
121	struct stat st;
122	struct timeval tp;
123	struct utmp utmp;
124	int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval;
125	int changepass;
126	uid_t uid;
127	char *domain, *p, *ep, *salt, *ttyn;
128	char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10];
129	char localhost[MAXHOSTNAMELEN];
130	char full_hostname[MAXHOSTNAMELEN];
131#ifdef	SKEY
132	int permit_passwd = 0;
133#endif
134
135	(void)signal(SIGALRM, timedout);
136	(void)alarm(timeout);
137	(void)signal(SIGQUIT, SIG_IGN);
138	(void)signal(SIGINT, SIG_IGN);
139	(void)setpriority(PRIO_PROCESS, 0, 0);
140
141	openlog("login", LOG_ODELAY, LOG_AUTH);
142
143	/*
144	 * -p is used by getty to tell login not to destroy the environment
145	 * -f is used to skip a second login authentication
146	 * -h is used by other servers to pass the name of the remote
147	 *    host to login so that it may be placed in utmp and wtmp
148	 */
149	*full_hostname = '\0';
150	domain = NULL;
151	if (gethostname(localhost, sizeof(localhost)) < 0)
152		syslog(LOG_ERR, "couldn't get local hostname: %m");
153	else
154		domain = strchr(localhost, '.');
155
156	fflag = hflag = pflag = 0;
157	uid = getuid();
158	while ((ch = getopt(argc, argv, "fh:p")) != EOF)
159		switch (ch) {
160		case 'f':
161			fflag = 1;
162			break;
163		case 'h':
164			if (uid)
165				errx(1, "-h option: %s", strerror(EPERM));
166			hflag = 1;
167			strncpy(full_hostname, optarg, sizeof(full_hostname)-1);
168			if (domain && (p = strchr(optarg, '.')) &&
169			    strcasecmp(p, domain) == 0)
170				*p = 0;
171			hostname = optarg;
172			break;
173		case 'p':
174			pflag = 1;
175			break;
176		case '?':
177		default:
178			if (!uid)
179				syslog(LOG_ERR, "invalid flag %c", ch);
180			(void)fprintf(stderr,
181			    "usage: login [-fp] [-h hostname] [username]\n");
182			exit(1);
183		}
184	argc -= optind;
185	argv += optind;
186
187	if (*argv) {
188		username = *argv;
189		ask = 0;
190	} else
191		ask = 1;
192
193	for (cnt = getdtablesize(); cnt > 2; cnt--)
194		(void)close(cnt);
195
196	ttyn = ttyname(STDIN_FILENO);
197	if (ttyn == NULL || *ttyn == '\0') {
198		(void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
199		ttyn = tname;
200	}
201	if (tty = strrchr(ttyn, '/'))
202		++tty;
203	else
204		tty = ttyn;
205
206	for (cnt = 0;; ask = 1) {
207		if (ask) {
208			fflag = 0;
209			getloginname();
210		}
211		rootlogin = 0;
212#ifdef	KERBEROS
213		if ((instance = strchr(username, '.')) != NULL) {
214			if (strncmp(instance, ".root", 5) == 0)
215				rootlogin = 1;
216			*instance++ = '\0';
217		} else
218			instance = "";
219#endif
220		if (strlen(username) > UT_NAMESIZE)
221			username[UT_NAMESIZE] = '\0';
222
223		/*
224		 * Note if trying multiple user names; log failures for
225		 * previous user name, but don't bother logging one failure
226		 * for nonexistent name (mistyped username).
227		 */
228		if (failures && strcmp(tbuf, username)) {
229			if (failures > (pwd ? 0 : 1))
230				badlogin(tbuf);
231			failures = 0;
232		}
233		(void)strcpy(tbuf, username);
234
235		if (pwd = getpwnam(username))
236			salt = pwd->pw_passwd;
237		else
238			salt = "xx";
239
240		/*
241		 * if we have a valid account name, and it doesn't have a
242		 * password, or the -f option was specified and the caller
243		 * is root or the caller isn't changing their uid, don't
244		 * authenticate.
245		 */
246		if (pwd) {
247			if (pwd->pw_uid == 0)
248				rootlogin = 1;
249
250			if (fflag && (uid == 0 || uid == pwd->pw_uid)) {
251				/* already authenticated */
252				break;
253			} else if (pwd->pw_passwd[0] == '\0') {
254				/* pretend password okay */
255				rval = 0;
256				goto ttycheck;
257			}
258		}
259
260		fflag = 0;
261
262		(void)setpriority(PRIO_PROCESS, 0, -4);
263
264#ifdef	SKEY
265		permit_passwd = skeyaccess(username, tty,
266					   hostname ? full_hostname : NULL,
267					   NULL);
268		p = skey_getpass("Password:", pwd, permit_passwd);
269		ep = skey_crypt(p, salt, pwd, permit_passwd);
270#else
271		p = getpass("Password:");
272		ep = crypt(p, salt);
273#endif
274
275		if (pwd) {
276#ifdef KERBEROS
277#ifdef SKEY
278			/*
279			 * Do not allow user to type in kerberos password
280			 * over the net (actually, this is ok for encrypted
281			 * links, but we have no way of determining if the
282			 * link is encrypted.
283			 */
284			if (!permit_password) {
285				rval = 1;		/* failed */
286			} else
287#endif
288			rval = klogin(pwd, instance, localhost, p);
289			if (rval != 0 && rootlogin && pwd->pw_uid != 0)
290				rootlogin = 0;
291			if (rval == 0)
292				authok = 1;
293			else if (rval == 1)
294				rval = strcmp(ep, pwd->pw_passwd);
295#else
296			rval = strcmp(ep, pwd->pw_passwd);
297#endif
298		}
299		memset(p, 0, strlen(p));
300
301		(void)setpriority(PRIO_PROCESS, 0, 0);
302
303	ttycheck:
304		/*
305		 * If trying to log in as root without Kerberos,
306		 * but with insecure terminal, refuse the login attempt.
307		 */
308#ifdef KERBEROS
309		if (authok == 0)
310#endif
311		if (pwd && !rval && rootlogin && !rootterm(tty)) {
312			(void)fprintf(stderr,
313			    "%s login refused on this terminal.\n",
314			    pwd->pw_name);
315			if (hostname)
316				syslog(LOG_NOTICE,
317				    "LOGIN %s REFUSED FROM %s ON TTY %s",
318				    pwd->pw_name, hostname, tty);
319			else
320				syslog(LOG_NOTICE,
321				    "LOGIN %s REFUSED ON TTY %s",
322				     pwd->pw_name, tty);
323			continue;
324		}
325
326		if (pwd && !rval)
327			break;
328
329		(void)printf("Login incorrect\n");
330		failures++;
331		/* we allow 10 tries, but after 3 we start backing off */
332		if (++cnt > 3) {
333			if (cnt >= 10) {
334				badlogin(username);
335				sleepexit(1);
336			}
337			sleep((u_int)((cnt - 3) * 5));
338		}
339	}
340
341	/* committed to login -- turn off timeout */
342	(void)alarm((u_int)0);
343
344	endpwent();
345
346	/* if user not super-user, check for disabled logins */
347	if (!rootlogin)
348		checknologin();
349
350	if (chdir(pwd->pw_dir) < 0) {
351		(void)printf("No home directory %s!\n", pwd->pw_dir);
352		if (chdir("/"))
353			exit(0);
354		pwd->pw_dir = "/";
355		(void)printf("Logging in with home = \"/\".\n");
356	}
357
358	quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
359
360	if (pwd->pw_change || pwd->pw_expire)
361		(void)gettimeofday(&tp, (struct timezone *)NULL);
362
363	changepass=0;
364	if (pwd->pw_change)
365		if (tp.tv_sec >= pwd->pw_change) {
366			(void)printf("Sorry -- your password has expired.\n");
367			changepass=1;
368		} else if (pwd->pw_change - tp.tv_sec <
369		    2 * DAYSPERWEEK * SECSPERDAY && !quietlog)
370			(void)printf("Warning: your password expires on %s",
371			    ctime(&pwd->pw_change));
372	if (pwd->pw_expire)
373		if (tp.tv_sec >= pwd->pw_expire) {
374			(void)printf("Sorry -- your account has expired.\n");
375			sleepexit(1);
376		} else if (pwd->pw_expire - tp.tv_sec <
377		    2 * DAYSPERWEEK * SECSPERDAY && !quietlog)
378			(void)printf("Warning: your account expires on %s",
379			    ctime(&pwd->pw_expire));
380
381	/* Nothing else left to fail -- really log in. */
382	memset((void *)&utmp, 0, sizeof(utmp));
383	(void)time(&utmp.ut_time);
384	(void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name));
385	if (hostname)
386		(void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
387	(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
388	login(&utmp);
389
390	dolastlog(quietlog);
391
392	/*
393	 * Set device protections, depending on what terminal the
394	 * user is logged in. This feature is used on Suns to give
395	 * console users better privacy.
396	 */
397	login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
398
399	(void)chown(ttyn, pwd->pw_uid,
400	    (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid);
401	(void)setgid(pwd->pw_gid);
402
403	initgroups(username, pwd->pw_gid);
404
405	if (*pwd->pw_shell == '\0')
406		pwd->pw_shell = _PATH_BSHELL;
407
408	/* Destroy environment unless user has requested its preservation. */
409	if (!pflag)
410		environ = envinit;
411	(void)setenv("HOME", pwd->pw_dir, 1);
412	(void)setenv("SHELL", pwd->pw_shell, 1);
413	if (term[0] == '\0')
414		(void)strncpy(term, stypeof(tty), sizeof(term));
415	(void)setenv("TERM", term, 0);
416	(void)setenv("LOGNAME", pwd->pw_name, 1);
417	(void)setenv("USER", pwd->pw_name, 1);
418	(void)setenv("PATH", _PATH_DEFPATH, 0);
419#ifdef KERBEROS
420	if (krbtkfile_env)
421		(void)setenv("KRBTKFILE", krbtkfile_env, 1);
422#endif
423
424	if (tty[sizeof("tty")-1] == 'd')
425		syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
426
427	/* If fflag is on, assume caller/authenticator has logged root login. */
428	if (rootlogin && fflag == 0)
429		if (hostname)
430			syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
431			    username, tty, hostname);
432		else
433			syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty);
434
435#ifdef KERBEROS
436	if (!quietlog && notickets == 1 && !noticketsdontcomplain)
437		(void)printf("Warning: no Kerberos tickets issued.\n");
438#endif
439
440#ifdef LOGALL
441	/*
442	 * Syslog each successful login, so we don't have to watch hundreds
443	 * of wtmp or lastlogin files.
444	 */
445	if (hostname) {
446		syslog(LOG_INFO, "login from %s as %s", hostname, pwd->pw_name);
447	} else {
448		syslog(LOG_INFO, "login on %s as %s", tty, pwd->pw_name);
449	}
450#endif
451
452	if (!quietlog) {
453		(void)printf("%s\n\t%s  %s\n\n",
454	    "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
455		    "The Regents of the University of California. ",
456		    "All rights reserved.");
457		motd();
458		(void)snprintf(tbuf,
459		    sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name);
460		if (stat(tbuf, &st) == 0 && st.st_size != 0)
461			(void)printf("You have %smail.\n",
462			    (st.st_mtime > st.st_atime) ? "new " : "");
463	}
464
465#ifdef LOGIN_ACCESS
466	if (login_access(pwd->pw_name, hostname ? full_hostname : tty) == 0) {
467		printf("Permission denied\n");
468		if (hostname)
469			syslog(LOG_NOTICE, "%s LOGIN REFUSED FROM %s",
470				pwd->pw_name, hostname);
471		else
472			syslog(LOG_NOTICE, "%s LOGIN REFUSED ON %s",
473				pwd->pw_name, tty);
474		sleepexit(1);
475	}
476#endif
477
478	(void)signal(SIGALRM, SIG_DFL);
479	(void)signal(SIGQUIT, SIG_DFL);
480	(void)signal(SIGINT, SIG_DFL);
481	(void)signal(SIGTSTP, SIG_IGN);
482
483	tbuf[0] = '-';
484	(void)strcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ?
485	    p + 1 : pwd->pw_shell);
486
487     	if (setlogin(pwd->pw_name) < 0)
488                syslog(LOG_ERR, "setlogin() failure: %m");
489
490	/* Discard permissions last so can't get killed and drop core. */
491	if (rootlogin)
492		(void) setuid(0);
493	else
494		(void) setuid(pwd->pw_uid);
495
496	if (changepass) {
497		int res;
498		if ((res=system(_PATH_CHPASS)))
499			sleepexit(1);
500	}
501
502	execlp(pwd->pw_shell, tbuf, 0);
503	err(1, "%s", pwd->pw_shell);
504}
505
506#ifdef	KERBEROS
507#define	NBUFSIZ		(UT_NAMESIZE + 1 + 5)	/* .root suffix */
508#else
509#define	NBUFSIZ		(UT_NAMESIZE + 1)
510#endif
511
512void
513getloginname()
514{
515	int ch;
516	char *p;
517	static char nbuf[NBUFSIZ];
518
519	for (;;) {
520		(void)printf("login: ");
521		for (p = nbuf; (ch = getchar()) != '\n'; ) {
522			if (ch == EOF) {
523				badlogin(username);
524				exit(0);
525			}
526			if (p < nbuf + (NBUFSIZ - 1))
527				*p++ = ch;
528		}
529		if (p > nbuf)
530			if (nbuf[0] == '-')
531				(void)fprintf(stderr,
532				    "login names may not start with '-'.\n");
533			else {
534				*p = '\0';
535				username = nbuf;
536				break;
537			}
538	}
539}
540
541int
542rootterm(ttyn)
543	char *ttyn;
544{
545	struct ttyent *t;
546
547	return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
548}
549
550jmp_buf motdinterrupt;
551
552void
553motd()
554{
555	int fd, nchars;
556	sig_t oldint;
557	char tbuf[8192];
558
559	if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0)
560		return;
561	oldint = signal(SIGINT, sigint);
562	if (setjmp(motdinterrupt) == 0)
563		while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0)
564			(void)write(fileno(stdout), tbuf, nchars);
565	(void)signal(SIGINT, oldint);
566	(void)close(fd);
567}
568
569/* ARGSUSED */
570void
571sigint(signo)
572	int signo;
573{
574
575	longjmp(motdinterrupt, 1);
576}
577
578/* ARGSUSED */
579void
580timedout(signo)
581	int signo;
582{
583
584	(void)fprintf(stderr, "Login timed out after %d seconds\n", timeout);
585	exit(0);
586}
587
588void
589checknologin()
590{
591	int fd, nchars;
592	char tbuf[8192];
593
594	if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) {
595		while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0)
596			(void)write(fileno(stdout), tbuf, nchars);
597		sleepexit(0);
598	}
599}
600
601void
602dolastlog(quiet)
603	int quiet;
604{
605	struct lastlog ll;
606	int fd;
607
608	if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
609		(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
610		if (!quiet) {
611			if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) &&
612			    ll.ll_time != 0) {
613				(void)printf("Last login: %.*s ",
614				    24-5, (char *)ctime(&ll.ll_time));
615				if (*ll.ll_host != '\0')
616					(void)printf("from %.*s\n",
617					    (int)sizeof(ll.ll_host),
618					    ll.ll_host);
619				else
620					(void)printf("on %.*s\n",
621					    (int)sizeof(ll.ll_line),
622					    ll.ll_line);
623			}
624			(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
625		}
626		memset((void *)&ll, 0, sizeof(ll));
627		(void)time(&ll.ll_time);
628		(void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
629		if (hostname)
630			(void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host));
631		(void)write(fd, (char *)&ll, sizeof(ll));
632		(void)close(fd);
633	}
634}
635
636void
637badlogin(name)
638	char *name;
639{
640
641	if (failures == 0)
642		return;
643	if (hostname) {
644		syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
645		    failures, failures > 1 ? "S" : "", hostname);
646		syslog(LOG_AUTHPRIV|LOG_NOTICE,
647		    "%d LOGIN FAILURE%s FROM %s, %s",
648		    failures, failures > 1 ? "S" : "", hostname, name);
649	} else {
650		syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
651		    failures, failures > 1 ? "S" : "", tty);
652		syslog(LOG_AUTHPRIV|LOG_NOTICE,
653		    "%d LOGIN FAILURE%s ON %s, %s",
654		    failures, failures > 1 ? "S" : "", tty, name);
655	}
656}
657
658#undef	UNKNOWN
659#define	UNKNOWN	"su"
660
661char *
662stypeof(ttyid)
663	char *ttyid;
664{
665	struct ttyent *t;
666
667	return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN);
668}
669
670void
671sleepexit(eval)
672	int eval;
673{
674
675	(void)sleep(5);
676	exit(eval);
677}
678
679
680