pico-login.c revision 146187 
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#if 0
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
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)login.c	8.4 (Berkeley) 4/2/94";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/release/picobsd/tinyware/login/pico-login.c 146187 2005-05-13 16:31:11Z ume $";
46#endif /* not lint */
47
48/*
49 * login [ name ]
50 * login -h hostname	(for telnetd, etc.)
51 * login -f name	(for pre-authenticated login: datakit, xterm, etc.)
52 */
53
54#include <sys/copyright.h>
55#include <sys/param.h>
56#include <sys/stat.h>
57#include <sys/socket.h>
58#include <sys/time.h>
59#include <sys/resource.h>
60#include <sys/file.h>
61#include <netinet/in.h>
62#include <arpa/inet.h>
63
64#include <err.h>
65#include <errno.h>
66#include <grp.h>
67#include <libutil.h>
68#include <login_cap.h>
69#include <netdb.h>
70#include <pwd.h>
71#include <setjmp.h>
72#include <signal.h>
73#include <stdio.h>
74#include <stdlib.h>
75#include <string.h>
76#include <syslog.h>
77#include <ttyent.h>
78#include <unistd.h>
79#include <utmp.h>
80
81#ifdef USE_PAM
82#include <security/pam_appl.h>
83#include <security/openpam.h>
84#include <sys/wait.h>
85#endif /* USE_PAM */
86
87#include "pathnames.h"
88
89void	 badlogin(char *);
90void	 checknologin(void);
91void	 dolastlog(int);
92void	 getloginname(void);
93void	 motd(const char *);
94int	 rootterm(char *);
95void	 sigint(int);
96void	 sleepexit(int);
97void	 refused(char *,char *,int);
98char	*stypeof(char *);
99void	 timedout(int);
100int	 login_access(char *, char *);
101void     login_fbtab(char *, uid_t, gid_t);
102
103#ifdef USE_PAM
104static int auth_pam(void);
105static int export_pam_environment(void);
106static int ok_to_export(const char *);
107
108static pam_handle_t *pamh = NULL;
109static char **environ_pam;
110
111#define PAM_END { \
112	if ((e = pam_setcred(pamh, PAM_DELETE_CRED)) != PAM_SUCCESS) \
113		syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, e)); \
114	if ((e = pam_close_session(pamh,0)) != PAM_SUCCESS) \
115		syslog(LOG_ERR, "pam_close_session: %s", pam_strerror(pamh, e)); \
116	if ((e = pam_end(pamh, e)) != PAM_SUCCESS) \
117		syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e)); \
118}
119#endif
120
121static int auth_traditional(void);
122extern void login(struct utmp *);
123static void usage(void);
124
125#define	TTYGRPNAME	"tty"		/* name of group to own ttys */
126#define	DEFAULT_BACKOFF	3
127#define	DEFAULT_RETRIES	10
128#define	DEFAULT_PROMPT		"login: "
129#define	DEFAULT_PASSWD_PROMPT	"Password:"
130
131/*
132 * This bounds the time given to login.  Not a define so it can
133 * be patched on machines where it's too small.
134 */
135u_int	timeout = 300;
136
137/* Buffer for signal handling of timeout */
138jmp_buf timeout_buf;
139
140struct	passwd *pwd;
141int	failures;
142char	*term, *envinit[1], *hostname, *tty, *username;
143const char *passwd_prompt, *prompt;
144char    full_hostname[MAXHOSTNAMELEN];
145
146int
147main(argc, argv)
148	int argc;
149	char *argv[];
150{
151	extern char **environ;
152	struct group *gr;
153	struct stat st;
154	struct timeval tp;
155	struct utmp utmp;
156	int rootok, retries, backoff;
157	int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval;
158	int changepass;
159	time_t warntime;
160	uid_t uid, euid;
161	gid_t egid;
162	char *p, *ttyn;
163	char tbuf[MAXPATHLEN + 2];
164	char tname[sizeof(_PATH_TTY) + 10];
165	const char *shell = NULL;
166	login_cap_t *lc = NULL;
167#ifdef USE_PAM
168	pid_t pid;
169	int e;
170#endif /* USE_PAM */
171
172	(void)signal(SIGQUIT, SIG_IGN);
173	(void)signal(SIGINT, SIG_IGN);
174	(void)signal(SIGHUP, SIG_IGN);
175	if (setjmp(timeout_buf)) {
176		if (failures)
177			badlogin(tbuf);
178		(void)fprintf(stderr, "Login timed out after %d seconds\n",
179		    timeout);
180		exit(0);
181	}
182	(void)signal(SIGALRM, timedout);
183	(void)alarm(timeout);
184	(void)setpriority(PRIO_PROCESS, 0, 0);
185
186	openlog("login", LOG_ODELAY, LOG_AUTH);
187
188	/*
189	 * -p is used by getty to tell login not to destroy the environment
190	 * -f is used to skip a second login authentication
191	 * -h is used by other servers to pass the name of the remote
192	 *    host to login so that it may be placed in utmp and wtmp
193	 */
194	*full_hostname = '\0';
195	term = NULL;
196
197	fflag = hflag = pflag = 0;
198	uid = getuid();
199	euid = geteuid();
200	egid = getegid();
201	while ((ch = getopt(argc, argv, "fh:p")) != -1)
202		switch (ch) {
203		case 'f':
204			fflag = 1;
205			break;
206		case 'h':
207			if (uid)
208				errx(1, "-h option: %s", strerror(EPERM));
209			hflag = 1;
210			if (strlcpy(full_hostname, optarg,
211			    sizeof(full_hostname)) >= sizeof(full_hostname))
212				errx(1, "-h option: %s: exceeds maximum "
213				    "hostname size", optarg);
214
215			trimdomain(optarg, UT_HOSTSIZE);
216
217			if (strlen(optarg) > UT_HOSTSIZE) {
218				struct addrinfo hints, *res;
219				int ga_err;
220
221				memset(&hints, 0, sizeof(hints));
222				hints.ai_family = AF_UNSPEC;
223				ga_err = getaddrinfo(optarg, NULL, &hints,
224				    &res);
225				if (ga_err == 0) {
226					char hostbuf[MAXHOSTNAMELEN];
227
228					getnameinfo(res->ai_addr,
229					    res->ai_addrlen,
230					    hostbuf,
231					    sizeof(hostbuf), NULL, 0,
232					    NI_NUMERICHOST);
233					optarg = strdup(hostbuf);
234					if (optarg == NULL) {
235						syslog(LOG_NOTICE,
236						    "strdup(): %m");
237						sleepexit(1);
238					}
239				} else
240					optarg = "invalid hostname";
241				if (res != NULL)
242					freeaddrinfo(res);
243			}
244			hostname = optarg;
245			break;
246		case 'p':
247			pflag = 1;
248			break;
249		case '?':
250		default:
251			if (!uid)
252				syslog(LOG_ERR, "invalid flag %c", ch);
253			usage();
254		}
255	argc -= optind;
256	argv += optind;
257
258	if (*argv) {
259		username = *argv;
260		ask = 0;
261	} else
262		ask = 1;
263
264	for (cnt = getdtablesize(); cnt > 2; cnt--)
265		(void)close(cnt);
266
267	ttyn = ttyname(STDIN_FILENO);
268	if (ttyn == NULL || *ttyn == '\0') {
269		(void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
270		ttyn = tname;
271	}
272	if ((tty = strrchr(ttyn, '/')) != NULL)
273		++tty;
274	else
275		tty = ttyn;
276
277	/*
278	 * Get "login-retries" & "login-backoff" from default class
279	 */
280	lc = login_getclass(NULL);
281	prompt = login_getcapstr(lc, "prompt", DEFAULT_PROMPT, DEFAULT_PROMPT);
282	passwd_prompt = login_getcapstr(lc, "passwd_prompt",
283	    DEFAULT_PASSWD_PROMPT, DEFAULT_PASSWD_PROMPT);
284	retries = login_getcapnum(lc, "login-retries", DEFAULT_RETRIES,
285	    DEFAULT_RETRIES);
286	backoff = login_getcapnum(lc, "login-backoff", DEFAULT_BACKOFF,
287	    DEFAULT_BACKOFF);
288	login_close(lc);
289	lc = NULL;
290
291	for (cnt = 0;; ask = 1) {
292		if (ask) {
293			fflag = 0;
294			getloginname();
295		}
296		rootlogin = 0;
297		rootok = rootterm(tty); /* Default (auth may change) */
298
299		if (strlen(username) > UT_NAMESIZE)
300			username[UT_NAMESIZE] = '\0';
301
302		/*
303		 * Note if trying multiple user names; log failures for
304		 * previous user name, but don't bother logging one failure
305		 * for nonexistent name (mistyped username).
306		 */
307		if (failures && strcmp(tbuf, username)) {
308			if (failures > (pwd ? 0 : 1))
309				badlogin(tbuf);
310		}
311		(void)strlcpy(tbuf, username, sizeof(tbuf));
312
313		pwd = getpwnam(username);
314
315		/*
316		 * if we have a valid account name, and it doesn't have a
317		 * password, or the -f option was specified and the caller
318		 * is root or the caller isn't changing their uid, don't
319		 * authenticate.
320		 */
321		if (pwd != NULL) {
322			if (pwd->pw_uid == 0)
323				rootlogin = 1;
324
325			if (fflag && (uid == (uid_t)0 ||
326			    uid == (uid_t)pwd->pw_uid)) {
327				/* already authenticated */
328				break;
329			} else if (pwd->pw_passwd[0] == '\0') {
330				if (!rootlogin || rootok) {
331					/* pretend password okay */
332					rval = 0;
333					goto ttycheck;
334				}
335			}
336		}
337
338		fflag = 0;
339
340		(void)setpriority(PRIO_PROCESS, 0, -4);
341
342#ifdef USE_PAM
343		/*
344		 * Try to authenticate using PAM.  If a PAM system error
345		 * occurs, perhaps because of a botched configuration,
346		 * then fall back to using traditional Unix authentication.
347		 */
348		if ((rval = auth_pam()) == -1)
349#endif /* USE_PAM */
350			rval = auth_traditional();
351
352		(void)setpriority(PRIO_PROCESS, 0, 0);
353
354#ifdef USE_PAM
355		/*
356		 * PAM authentication may have changed "pwd" to the
357		 * entry for the template user.  Check again to see if
358		 * this is a root login after all.
359		 */
360		if (pwd != NULL && pwd->pw_uid == 0)
361			rootlogin = 1;
362#endif /* USE_PAM */
363
364	ttycheck:
365		/*
366		 * If trying to log in as root without Kerberos,
367		 * but with insecure terminal, refuse the login attempt.
368		 */
369		if (pwd && !rval) {
370			if (rootlogin && !rootok)
371				refused(NULL, "NOROOT", 0);
372			else	/* valid password & authenticated */
373				break;
374		}
375
376		(void)printf("Login incorrect\n");
377		failures++;
378
379		/*
380		 * we allow up to 'retry' (10) tries,
381		 * but after 'backoff' (3) we start backing off
382		 */
383		if (++cnt > backoff) {
384			if (cnt >= retries) {
385				badlogin(username);
386				sleepexit(1);
387			}
388			sleep((u_int)((cnt - backoff) * 5));
389		}
390	}
391
392	/* committed to login -- turn off timeout */
393	(void)alarm((u_int)0);
394	(void)signal(SIGHUP, SIG_DFL);
395
396	endpwent();
397
398	/*
399	 * Establish the login class.
400	 */
401	lc = login_getpwclass(pwd);
402
403	/* if user not super-user, check for disabled logins */
404	if (!rootlogin)
405		auth_checknologin(lc);
406
407	quietlog = login_getcapbool(lc, "hushlogin", 0);
408	/*
409	 * Switching needed for NFS with root access disabled.
410	 *
411	 * XXX: This change fails to modify the additional groups for the
412	 * process, and as such, may restrict rights normally granted
413	 * through those groups.
414	 */
415	(void)setegid(pwd->pw_gid);
416	(void)seteuid(rootlogin ? 0 : pwd->pw_uid);
417	if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) {
418		if (login_getcapbool(lc, "requirehome", 0))
419			refused("Home directory not available", "HOMEDIR", 1);
420		if (chdir("/") < 0)
421			refused("Cannot find root directory", "ROOTDIR", 1);
422		if (!quietlog || *pwd->pw_dir)
423			printf("No home directory.\nLogging in with home = \"/\".\n");
424		pwd->pw_dir = "/";
425	}
426	(void)seteuid(euid);
427	(void)setegid(egid);
428	if (!quietlog)
429		quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
430
431	if (pwd->pw_change || pwd->pw_expire)
432		(void)gettimeofday(&tp, (struct timezone *)NULL);
433
434#define	DEFAULT_WARN  (2L * 7L * 86400L)  /* Two weeks */
435
436	warntime = login_getcaptime(lc, "warnexpire", DEFAULT_WARN,
437	    DEFAULT_WARN);
438
439	if (pwd->pw_expire) {
440		if (tp.tv_sec >= pwd->pw_expire) {
441			refused("Sorry -- your account has expired", "EXPIRED",
442			    1);
443		} else if (pwd->pw_expire - tp.tv_sec < warntime && !quietlog)
444			(void)printf("Warning: your account expires on %s",
445			    ctime(&pwd->pw_expire));
446	}
447
448	warntime = login_getcaptime(lc, "warnpassword", DEFAULT_WARN,
449	    DEFAULT_WARN);
450
451	changepass = 0;
452	if (pwd->pw_change) {
453		if (tp.tv_sec >= pwd->pw_change) {
454			(void)printf("Sorry -- your password has expired.\n");
455			changepass = 1;
456			syslog(LOG_INFO, "%s Password expired - forcing change",
457			    pwd->pw_name);
458		} else if (pwd->pw_change - tp.tv_sec < warntime && !quietlog)
459			(void)printf("Warning: your password expires on %s",
460			    ctime(&pwd->pw_change));
461	}
462
463	if (lc != NULL) {
464		if (hostname) {
465			struct addrinfo hints, *res;
466			int ga_err;
467
468			memset(&hints, 0, sizeof(hints));
469			hints.ai_family = AF_UNSPEC;
470			ga_err = getaddrinfo(full_hostname, NULL, &hints,
471					     &res);
472			if (ga_err == 0) {
473				char hostbuf[MAXHOSTNAMELEN];
474
475				getnameinfo(res->ai_addr, res->ai_addrlen,
476				    hostbuf, sizeof(hostbuf), NULL, 0,
477				    NI_NUMERICHOST);
478				if ((optarg = strdup(hostbuf)) == NULL) {
479					syslog(LOG_NOTICE, "strdup(): %m");
480					sleepexit(1);
481				}
482			} else
483				optarg = NULL;
484			if (res != NULL)
485				freeaddrinfo(res);
486			if (!auth_hostok(lc, full_hostname, optarg))
487				refused("Permission denied", "HOST", 1);
488		}
489
490		if (!auth_ttyok(lc, tty))
491			refused("Permission denied", "TTY", 1);
492
493		if (!auth_timeok(lc, time(NULL)))
494			refused("Logins not available right now", "TIME", 1);
495	}
496        shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell);
497	if (*pwd->pw_shell == '\0')
498		pwd->pw_shell = _PATH_BSHELL;
499	if (*shell == '\0')   /* Not overridden */
500		shell = pwd->pw_shell;
501	if ((shell = strdup(shell)) == NULL) {
502		syslog(LOG_NOTICE, "strdup(): %m");
503		sleepexit(1);
504	}
505
506#ifdef LOGIN_ACCESS
507	if (login_access(pwd->pw_name, hostname ? full_hostname : tty) == 0)
508		refused("Permission denied", "ACCESS", 1);
509#endif /* LOGIN_ACCESS */
510
511	/* Nothing else left to fail -- really log in. */
512	memset((void *)&utmp, 0, sizeof(utmp));
513	(void)time(&utmp.ut_time);
514	(void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name));
515	if (hostname)
516		(void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
517	(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
518	login(&utmp);
519
520	dolastlog(quietlog);
521
522	/*
523	 * Set device protections, depending on what terminal the
524	 * user is logged in. This feature is used on Suns to give
525	 * console users better privacy.
526	 */
527	login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
528
529	/*
530	 * Clear flags of the tty.  None should be set, and when the
531	 * user sets them otherwise, this can cause the chown to fail.
532	 * Since it isn't clear that flags are useful on character
533	 * devices, we just clear them.
534	 */
535	if (chflags(ttyn, 0) && errno != EOPNOTSUPP)
536		syslog(LOG_ERR, "chmod(%s): %m", ttyn);
537	if (chown(ttyn, pwd->pw_uid,
538	    (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid))
539		syslog(LOG_ERR, "chmod(%s): %m", ttyn);
540
541
542	/*
543	 * Preserve TERM if it happens to be already set.
544	 */
545	if ((term = getenv("TERM")) != NULL) {
546		if ((term = strdup(term)) == NULL) {
547			syslog(LOG_NOTICE,
548			    "strdup(): %m");
549			sleepexit(1);
550		}
551	}
552
553	/*
554	 * Exclude cons/vt/ptys only, assume dialup otherwise
555	 * TODO: Make dialup tty determination a library call
556	 * for consistency (finger etc.)
557	 */
558	if (hostname==NULL && isdialuptty(tty))
559		syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
560
561#ifdef LOGALL
562	/*
563	 * Syslog each successful login, so we don't have to watch hundreds
564	 * of wtmp or lastlogin files.
565	 */
566	if (hostname)
567		syslog(LOG_INFO, "login from %s on %s as %s",
568		       full_hostname, tty, pwd->pw_name);
569	else
570		syslog(LOG_INFO, "login on %s as %s",
571		       tty, pwd->pw_name);
572#endif
573
574	/*
575	 * If fflag is on, assume caller/authenticator has logged root login.
576	 */
577	if (rootlogin && fflag == 0)
578	{
579		if (hostname)
580			syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
581			    username, tty, full_hostname);
582		else
583			syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s",
584			    username, tty);
585	}
586
587	/*
588	 * Destroy environment unless user has requested its preservation.
589	 * We need to do this before setusercontext() because that may
590	 * set or reset some environment variables.
591	 */
592	if (!pflag)
593		environ = envinit;
594
595	/*
596	 * PAM modules might add supplementary groups during pam_setcred().
597	 */
598	if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
599                syslog(LOG_ERR, "setusercontext() failed - exiting");
600		exit(1);
601	}
602
603#ifdef USE_PAM
604	if (pamh) {
605		if ((e = pam_open_session(pamh, 0)) != PAM_SUCCESS) {
606			syslog(LOG_ERR, "pam_open_session: %s",
607			    pam_strerror(pamh, e));
608		} else if ((e = pam_setcred(pamh, PAM_ESTABLISH_CRED))
609		    != PAM_SUCCESS) {
610			syslog(LOG_ERR, "pam_setcred: %s",
611			    pam_strerror(pamh, e));
612		}
613
614	        /*
615	         * Add any environmental variables that the
616	         * PAM modules may have set.
617		 * Call *after* opening session!
618		 */
619		if (pamh) {
620		  environ_pam = pam_getenvlist(pamh);
621		  if (environ_pam)
622			export_pam_environment();
623		}
624
625		/*
626		 * We must fork() before setuid() because we need to call
627		 * pam_close_session() as root.
628		 */
629		pid = fork();
630		if (pid < 0) {
631			err(1, "fork");
632			PAM_END;
633			exit(0);
634		} else if (pid) {
635			/* parent - wait for child to finish, then cleanup
636			   session */
637			wait(NULL);
638			PAM_END;
639			exit(0);
640		} else {
641			if ((e = pam_end(pamh, 0)) != PAM_SUCCESS)
642				syslog(LOG_ERR, "pam_end: %s",
643				    pam_strerror(pamh, e));
644		}
645	}
646#endif /* USE_PAM */
647
648	/*
649	 * We don't need to be root anymore, so
650	 * set the user and session context
651	 */
652	if (setlogin(username) != 0) {
653                syslog(LOG_ERR, "setlogin(%s): %m - exiting", username);
654		exit(1);
655	}
656	if (setusercontext(lc, pwd, pwd->pw_uid,
657	    LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) {
658                syslog(LOG_ERR, "setusercontext() failed - exiting");
659		exit(1);
660	}
661
662	(void)setenv("SHELL", pwd->pw_shell, 1);
663	(void)setenv("HOME", pwd->pw_dir, 1);
664	if (term != NULL && *term != '\0')
665		(void)setenv("TERM", term, 1);		/* Preset overrides */
666	else {
667		(void)setenv("TERM", stypeof(tty), 0);	/* Fallback doesn't */
668	}
669	(void)setenv("LOGNAME", username, 1);
670	(void)setenv("USER", username, 1);
671	(void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0);
672
673	if (!quietlog) {
674		const char *cw;
675
676		cw = login_getcapstr(lc, "copyright", NULL, NULL);
677		if (cw != NULL && access(cw, F_OK) == 0)
678			motd(cw);
679		else
680		    (void)printf("%s\n\t%s %s\n",
681	"Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
682	"The Regents of the University of California. ",
683	"All rights reserved.");
684
685		(void)printf("\n");
686
687		cw = login_getcapstr(lc, "welcome", NULL, NULL);
688		if (cw == NULL || access(cw, F_OK) != 0)
689			cw = _PATH_MOTDFILE;
690		motd(cw);
691
692		cw = getenv("MAIL");	/* $MAIL may have been set by class */
693		if (cw != NULL)
694			strlcpy(tbuf, cw, sizeof(tbuf));
695		else
696			snprintf(tbuf, sizeof(tbuf), "%s/%s", _PATH_MAILDIR,
697			    pwd->pw_name);
698		if (stat(tbuf, &st) == 0 && st.st_size != 0)
699			(void)printf("You have %smail.\n",
700			    (st.st_mtime > st.st_atime) ? "new " : "");
701	}
702
703	login_close(lc);
704
705	(void)signal(SIGALRM, SIG_DFL);
706	(void)signal(SIGQUIT, SIG_DFL);
707	(void)signal(SIGINT, SIG_DFL);
708	(void)signal(SIGTSTP, SIG_IGN);
709
710	/*
711	 * Login shells have a leading '-' in front of argv[0]
712	 */
713	if (snprintf(tbuf, sizeof(tbuf), "-%s",
714	    (p = strrchr(pwd->pw_shell, '/')) ? p + 1 : pwd->pw_shell) >=
715	    sizeof(tbuf)) {
716		syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size",
717		    username);
718		errx(1, "shell exceeds maximum pathname size");
719	}
720
721	execlp(shell, tbuf, (char *)0);
722	err(1, "%s", shell);
723}
724
725static int
726auth_traditional()
727{
728	int rval;
729	char *p;
730	char *ep;
731	char *salt;
732
733	rval = 1;
734	salt = pwd != NULL ? pwd->pw_passwd : "xx";
735
736	p = getpass(passwd_prompt);
737	ep = crypt(p, salt);
738
739	if (pwd) {
740		if (!p[0] && pwd->pw_passwd[0])
741			ep = ":";
742		if (strcmp(ep, pwd->pw_passwd) == 0)
743			rval = 0;
744	}
745
746	/* clear entered password */
747	memset(p, 0, strlen(p));
748	return rval;
749}
750
751#ifdef USE_PAM
752/*
753 * Attempt to authenticate the user using PAM.  Returns 0 if the user is
754 * authenticated, or 1 if not authenticated.  If some sort of PAM system
755 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
756 * function returns -1.  This can be used as an indication that we should
757 * fall back to a different authentication mechanism.
758 */
759static int
760auth_pam()
761{
762	const char *tmpl_user;
763	const void *item;
764	int rval;
765	int e;
766	static struct pam_conv conv = { openpam_ttyconv, NULL };
767
768	if ((e = pam_start("login", username, &conv, &pamh)) != PAM_SUCCESS) {
769		syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e));
770		return -1;
771	}
772	if ((e = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS) {
773		syslog(LOG_ERR, "pam_set_item(PAM_TTY): %s",
774		    pam_strerror(pamh, e));
775		return -1;
776	}
777	if (hostname != NULL &&
778	    (e = pam_set_item(pamh, PAM_RHOST, full_hostname)) != PAM_SUCCESS) {
779		syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
780		    pam_strerror(pamh, e));
781		return -1;
782	}
783	e = pam_authenticate(pamh, 0);
784	switch (e) {
785
786	case PAM_SUCCESS:
787		/*
788		 * With PAM we support the concept of a "template"
789		 * user.  The user enters a login name which is
790		 * authenticated by PAM, usually via a remote service
791		 * such as RADIUS or TACACS+.  If authentication
792		 * succeeds, a different but related "template" name
793		 * is used for setting the credentials, shell, and
794		 * home directory.  The name the user enters need only
795		 * exist on the remote authentication server, but the
796		 * template name must be present in the local password
797		 * database.
798		 *
799		 * This is supported by two various mechanisms in the
800		 * individual modules.  However, from the application's
801		 * point of view, the template user is always passed
802		 * back as a changed value of the PAM_USER item.
803		 */
804		if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
805		    PAM_SUCCESS) {
806			tmpl_user = (const char *) item;
807			if (strcmp(username, tmpl_user) != 0)
808				pwd = getpwnam(tmpl_user);
809		} else
810			syslog(LOG_ERR, "Couldn't get PAM_USER: %s",
811			    pam_strerror(pamh, e));
812		rval = 0;
813		break;
814
815	case PAM_AUTH_ERR:
816	case PAM_USER_UNKNOWN:
817	case PAM_MAXTRIES:
818		rval = 1;
819		break;
820
821	default:
822		syslog(LOG_ERR, "pam_authenticate: %s", pam_strerror(pamh, e));
823		rval = -1;
824		break;
825	}
826
827	if (rval == 0) {
828		e = pam_acct_mgmt(pamh, 0);
829		if (e == PAM_NEW_AUTHTOK_REQD) {
830			e = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
831			if (e != PAM_SUCCESS) {
832				syslog(LOG_ERR, "pam_chauthtok: %s",
833				    pam_strerror(pamh, e));
834				rval = 1;
835			}
836		} else if (e != PAM_SUCCESS) {
837			rval = 1;
838		}
839	}
840
841	if (rval != 0) {
842		if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
843			syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
844		}
845		pamh = NULL;
846	}
847	return rval;
848}
849
850static int
851export_pam_environment()
852{
853	char	**pp;
854
855	for (pp = environ_pam; *pp != NULL; pp++) {
856		if (ok_to_export(*pp))
857			(void) putenv(*pp);
858		free(*pp);
859	}
860	return PAM_SUCCESS;
861}
862
863/*
864 * Sanity checks on PAM environmental variables:
865 * - Make sure there is an '=' in the string.
866 * - Make sure the string doesn't run on too long.
867 * - Do not export certain variables.  This list was taken from the
868 *   Solaris pam_putenv(3) man page.
869 */
870static int
871ok_to_export(s)
872	const char *s;
873{
874	static const char *noexport[] = {
875		"SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH",
876		"IFS", "PATH", NULL
877	};
878	const char **pp;
879	size_t n;
880
881	if (strlen(s) > 1024 || strchr(s, '=') == NULL)
882		return 0;
883	if (strncmp(s, "LD_", 3) == 0)
884		return 0;
885	for (pp = noexport; *pp != NULL; pp++) {
886		n = strlen(*pp);
887		if (s[n] == '=' && strncmp(s, *pp, n) == 0)
888			return 0;
889	}
890	return 1;
891}
892#endif /* USE_PAM */
893
894static void
895usage()
896{
897
898	(void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n");
899	exit(1);
900}
901
902/*
903 * Allow for authentication style and/or kerberos instance
904 */
905
906#define	NBUFSIZ		UT_NAMESIZE + 64
907
908void
909getloginname()
910{
911	int ch;
912	char *p;
913	static char nbuf[NBUFSIZ];
914
915	for (;;) {
916		(void)printf("%s", prompt);
917		for (p = nbuf; (ch = getchar()) != '\n'; ) {
918			if (ch == EOF) {
919				badlogin(username);
920				exit(0);
921			}
922			if (p < nbuf + (NBUFSIZ - 1))
923				*p++ = ch;
924		}
925		if (p > nbuf) {
926			if (nbuf[0] == '-')
927				(void)fprintf(stderr,
928				    "login names may not start with '-'.\n");
929			else {
930				*p = '\0';
931				username = nbuf;
932				break;
933			}
934		}
935	}
936}
937
938int
939rootterm(ttyn)
940	char *ttyn;
941{
942	struct ttyent *t;
943
944	return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
945}
946
947volatile int motdinterrupt;
948
949void
950sigint(signo)
951	int signo __unused;
952{
953	motdinterrupt = 1;
954}
955
956void
957motd(motdfile)
958	const char *motdfile;
959{
960	int fd, nchars;
961	sig_t oldint;
962	char tbuf[256];
963
964	if ((fd = open(motdfile, O_RDONLY, 0)) < 0)
965		return;
966	motdinterrupt = 0;
967	oldint = signal(SIGINT, sigint);
968	while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0 && !motdinterrupt)
969		(void)write(fileno(stdout), tbuf, nchars);
970	(void)signal(SIGINT, oldint);
971	(void)close(fd);
972}
973
974/* ARGSUSED */
975void
976timedout(signo)
977	int signo;
978{
979
980	longjmp(timeout_buf, signo);
981}
982
983
984void
985dolastlog(quiet)
986	int quiet;
987{
988	struct lastlog ll;
989	int fd;
990
991	if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
992		(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
993		if (!quiet) {
994			if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) &&
995			    ll.ll_time != 0) {
996				(void)printf("Last login: %.*s ",
997				    24-5, (char *)ctime(&ll.ll_time));
998				if (*ll.ll_host != '\0')
999					(void)printf("from %.*s\n",
1000					    (int)sizeof(ll.ll_host),
1001					    ll.ll_host);
1002				else
1003					(void)printf("on %.*s\n",
1004					    (int)sizeof(ll.ll_line),
1005					    ll.ll_line);
1006			}
1007			(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
1008		}
1009		memset((void *)&ll, 0, sizeof(ll));
1010		(void)time(&ll.ll_time);
1011		(void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
1012		if (hostname)
1013			(void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host));
1014		(void)write(fd, (char *)&ll, sizeof(ll));
1015		(void)close(fd);
1016	} else {
1017		syslog(LOG_ERR, "cannot open %s: %m", _PATH_LASTLOG);
1018	}
1019}
1020
1021void
1022badlogin(name)
1023	char *name;
1024{
1025
1026	if (failures == 0)
1027		return;
1028	if (hostname) {
1029		syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
1030		    failures, failures > 1 ? "S" : "", full_hostname);
1031		syslog(LOG_AUTHPRIV|LOG_NOTICE,
1032		    "%d LOGIN FAILURE%s FROM %s, %s",
1033		    failures, failures > 1 ? "S" : "", full_hostname, name);
1034	} else {
1035		syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
1036		    failures, failures > 1 ? "S" : "", tty);
1037		syslog(LOG_AUTHPRIV|LOG_NOTICE,
1038		    "%d LOGIN FAILURE%s ON %s, %s",
1039		    failures, failures > 1 ? "S" : "", tty, name);
1040	}
1041	failures = 0;
1042}
1043
1044#undef	UNKNOWN
1045#define	UNKNOWN	"su"
1046
1047char *
1048stypeof(ttyid)
1049	char *ttyid;
1050{
1051	struct ttyent *t;
1052
1053	if (ttyid != NULL && *ttyid != '\0') {
1054		t = getttynam(ttyid);
1055		if (t != NULL && t->ty_type != NULL)
1056			return (t->ty_type);
1057	}
1058	return (UNKNOWN);
1059}
1060
1061void
1062refused(msg, rtype, lout)
1063	char *msg;
1064	char *rtype;
1065	int lout;
1066{
1067
1068	if (msg != NULL)
1069	    printf("%s.\n", msg);
1070	if (hostname)
1071		syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s",
1072		    pwd->pw_name, rtype, full_hostname, tty);
1073	else
1074		syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s",
1075		    pwd->pw_name, rtype, tty);
1076	if (lout)
1077		sleepexit(1);
1078}
1079
1080void
1081sleepexit(eval)
1082	int eval;
1083{
1084
1085	(void)sleep(5);
1086	exit(eval);
1087}
1088