2 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 2002 Networks Associates Technologies, Inc.
7 * Portions of this software were developed for the FreeBSD Project by
8 * ThinkSec AS and NAI Labs, the Security Research Division of Network
9 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
10 * ("CBOSS"), as part of the DARPA CHATS research program.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
43 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94";
47 #include <sys/cdefs.h>
48 __FBSDID("$FreeBSD$");
52 * login -h hostname (for telnetd, etc.)
53 * login -f name (for pre-authenticated login: datakit, xterm, etc.)
56 #include <sys/param.h>
60 #include <sys/resource.h>
67 #include <login_cap.h>
78 #include <security/pam_appl.h>
79 #include <security/openpam.h>
82 #include "pathnames.h"
84 static int auth_pam(void);
85 static void bail(int, int);
86 static int export(const char *);
87 static void export_pam_environment(void);
88 static int motd(const char *);
89 static void badlogin(char *);
90 static char *getloginname(void);
91 static void pam_syslog(const char *);
92 static void pam_cleanup(void);
93 static void refused(const char *, const char *, int);
94 static const char *stypeof(char *);
95 static void sigint(int);
96 static void timedout(int);
97 static void usage(void);
99 #define TTYGRPNAME "tty" /* group to own ttys */
100 #define DEFAULT_BACKOFF 3
101 #define DEFAULT_RETRIES 10
102 #define DEFAULT_PROMPT "login: "
103 #define DEFAULT_PASSWD_PROMPT "Password:"
104 #define TERM_UNKNOWN "su"
105 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */
106 #define NO_SLEEP_EXIT 0
110 * This bounds the time given to login. Not a define so it can
111 * be patched on machines where it's too small.
113 static u_int timeout = 300;
115 /* Buffer for signal handling of timeout */
116 static jmp_buf timeout_buf;
121 static char *envinit[1]; /* empty environment list */
124 * Command line flags and arguments
126 static int fflag; /* -f: do not perform authentication */
127 static int hflag; /* -h: login from remote host */
128 static char *hostname; /* hostname from command line */
129 static int pflag; /* -p: preserve environment */
134 static char *username; /* user name */
135 static char *olduser; /* previous user name */
140 static char default_prompt[] = DEFAULT_PROMPT;
141 static const char *prompt;
142 static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT;
143 static const char *passwd_prompt;
150 static pam_handle_t *pamh = NULL;
151 static struct pam_conv pamc = { openpam_ttyconv, NULL };
153 static int pam_silent = PAM_SILENT;
154 static int pam_cred_established;
155 static int pam_session_established;
158 main(int argc, char *argv[])
162 int retries, backoff;
163 int ask, ch, cnt, quietlog, rootlogin, rval;
168 char tname[sizeof(_PATH_TTY) + 10];
171 const char *shell = NULL;
172 login_cap_t *lc = NULL;
173 login_cap_t *lc_user = NULL;
176 char auditsuccess = 1;
179 (void)signal(SIGQUIT, SIG_IGN);
180 (void)signal(SIGINT, SIG_IGN);
181 (void)signal(SIGHUP, SIG_IGN);
182 if (setjmp(timeout_buf)) {
185 (void)fprintf(stderr, "Login timed out after %d seconds\n",
187 bail(NO_SLEEP_EXIT, 0);
189 (void)signal(SIGALRM, timedout);
190 (void)alarm(timeout);
191 (void)setpriority(PRIO_PROCESS, 0, 0);
193 openlog("login", LOG_ODELAY, LOG_AUTH);
199 while ((ch = getopt(argc, argv, "fh:p")) != -1)
206 errx(1, "-h option: %s", strerror(EPERM));
207 if (strlen(optarg) >= MAXHOSTNAMELEN)
208 errx(1, "-h option: %s: exceeds maximum "
209 "hostname size", optarg);
219 syslog(LOG_ERR, "invalid flag %c", ch);
226 username = strdup(*argv);
227 if (username == NULL)
234 setproctitle("-%s", getprogname());
241 ttyn = ttyname(STDIN_FILENO);
242 if (ttyn == NULL || *ttyn == '\0') {
243 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
246 if (strncmp(ttyn, _PATH_DEV, sizeof _PATH_DEV - 1) == 0)
247 tty = ttyn + sizeof _PATH_DEV - 1;
252 * Get "login-retries" & "login-backoff" from default class
254 lc = login_getclass(NULL);
255 prompt = login_getcapstr(lc, "login_prompt",
256 default_prompt, default_prompt);
257 passwd_prompt = login_getcapstr(lc, "passwd_prompt",
258 default_passwd_prompt, default_passwd_prompt);
259 retries = login_getcapnum(lc, "login-retries",
260 DEFAULT_RETRIES, DEFAULT_RETRIES);
261 backoff = login_getcapnum(lc, "login-backoff",
262 DEFAULT_BACKOFF, DEFAULT_BACKOFF);
267 * Try to authenticate the user until we succeed or time out.
269 for (cnt = 0;; ask = 1) {
275 username = getloginname();
280 * Note if trying multiple user names; log failures for
281 * previous user name, but don't bother logging one failure
282 * for nonexistent name (mistyped username).
284 if (failures && strcmp(olduser, username) != 0) {
285 if (failures > (pwd ? 0 : 1))
290 * Load the PAM policy and set some variables
292 pam_err = pam_start("login", username, &pamc, &pamh);
293 if (pam_err != PAM_SUCCESS) {
294 pam_syslog("pam_start()");
296 au_login_fail("PAM Error", 1);
298 bail(NO_SLEEP_EXIT, 1);
300 pam_err = pam_set_item(pamh, PAM_TTY, tty);
301 if (pam_err != PAM_SUCCESS) {
302 pam_syslog("pam_set_item(PAM_TTY)");
304 au_login_fail("PAM Error", 1);
306 bail(NO_SLEEP_EXIT, 1);
308 pam_err = pam_set_item(pamh, PAM_RHOST, hostname);
309 if (pam_err != PAM_SUCCESS) {
310 pam_syslog("pam_set_item(PAM_RHOST)");
312 au_login_fail("PAM Error", 1);
314 bail(NO_SLEEP_EXIT, 1);
317 pwd = getpwnam(username);
318 if (pwd != NULL && pwd->pw_uid == 0)
322 * If the -f option was specified and the caller is
323 * root or the caller isn't changing their uid, don't
326 if (pwd != NULL && fflag &&
327 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) {
328 /* already authenticated */
331 auditsuccess = 0; /* opened a terminal window only */
335 (void)setpriority(PRIO_PROCESS, 0, -4);
337 (void)setpriority(PRIO_PROCESS, 0, 0);
340 if (pwd && rval == 0)
346 * We are not exiting here, but this corresponds to a failed
347 * login event, so set exitstatus to 1.
350 au_login_fail("Login incorrect", 1);
353 (void)printf("Login incorrect\n");
359 * Allow up to 'retry' (10) attempts, but start
360 * backing off after 'backoff' (3) attempts.
362 if (++cnt > backoff) {
363 if (cnt >= retries) {
367 sleep((u_int)((cnt - backoff) * 5));
371 /* committed to login -- turn off timeout */
372 (void)alarm((u_int)0);
373 (void)signal(SIGHUP, SIG_DFL);
378 /* Audit successful login. */
384 * Establish the login class.
386 lc = login_getpwclass(pwd);
387 lc_user = login_getuserclass(pwd);
389 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0)))
390 quietlog = login_getcapbool(lc, "hushlogin", 0);
393 * Switching needed for NFS with root access disabled.
395 * XXX: This change fails to modify the additional groups for the
396 * process, and as such, may restrict rights normally granted
397 * through those groups.
399 (void)setegid(pwd->pw_gid);
400 (void)seteuid(rootlogin ? 0 : pwd->pw_uid);
401 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) {
402 if (login_getcapbool(lc, "requirehome", 0))
403 refused("Home directory not available", "HOMEDIR", 1);
405 refused("Cannot find root directory", "ROOTDIR", 1);
406 if (!quietlog || *pwd->pw_dir)
407 printf("No home directory.\nLogging in with home = \"/\".\n");
408 pwd->pw_dir = strdup("/");
409 if (pwd->pw_dir == NULL) {
410 syslog(LOG_NOTICE, "strdup(): %m");
417 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
422 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell);
423 if (*pwd->pw_shell == '\0')
424 pwd->pw_shell = strdup(_PATH_BSHELL);
425 if (pwd->pw_shell == NULL) {
426 syslog(LOG_NOTICE, "strdup(): %m");
429 if (*shell == '\0') /* Not overridden */
430 shell = pwd->pw_shell;
431 if ((shell = strdup(shell)) == NULL) {
432 syslog(LOG_NOTICE, "strdup(): %m");
437 * Set device protections, depending on what terminal the
438 * user is logged in. This feature is used on Suns to give
439 * console users better privacy.
441 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
444 * Clear flags of the tty. None should be set, and when the
445 * user sets them otherwise, this can cause the chown to fail.
446 * Since it isn't clear that flags are useful on character
447 * devices, we just clear them.
449 * We don't log in the case of EOPNOTSUPP because dev might be
450 * on NFS, which doesn't support chflags.
452 * We don't log in the EROFS because that means that /dev is on
453 * a read only file system and we assume that the permissions there
456 if (ttyn != tname && chflags(ttyn, 0))
457 if (errno != EOPNOTSUPP && errno != EROFS)
458 syslog(LOG_ERR, "chflags(%s): %m", ttyn);
459 if (ttyn != tname && chown(ttyn, pwd->pw_uid,
460 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid))
462 syslog(LOG_ERR, "chown(%s): %m", ttyn);
465 * Exclude cons/vt/ptys only, assume dialup otherwise
466 * TODO: Make dialup tty determination a library call
467 * for consistency (finger etc.)
469 if (hflag && isdialuptty(tty))
470 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
474 * Syslog each successful login, so we don't have to watch
475 * hundreds of wtmp or lastlogin files.
478 syslog(LOG_INFO, "login from %s on %s as %s",
479 hostname, tty, pwd->pw_name);
481 syslog(LOG_INFO, "login on %s as %s",
486 * If fflag is on, assume caller/authenticator has logged root
489 if (rootlogin && fflag == 0) {
491 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
492 username, tty, hostname);
494 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s",
499 * Destroy environment unless user has requested its
500 * preservation - but preserve TERM in all cases
502 term = getenv("TERM");
506 setenv("TERM", term, 0);
509 * PAM modules might add supplementary groups during pam_setcred().
511 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
512 syslog(LOG_ERR, "setusercontext() failed - exiting");
513 bail(NO_SLEEP_EXIT, 1);
516 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED);
517 if (pam_err != PAM_SUCCESS) {
518 pam_syslog("pam_setcred()");
519 bail(NO_SLEEP_EXIT, 1);
521 pam_cred_established = 1;
523 pam_err = pam_open_session(pamh, pam_silent);
524 if (pam_err != PAM_SUCCESS) {
525 pam_syslog("pam_open_session()");
526 bail(NO_SLEEP_EXIT, 1);
528 pam_session_established = 1;
531 * We must fork() before setuid() because we need to call
532 * pam_close_session() as root.
537 } else if (pid != 0) {
539 * Parent: wait for child to finish, then clean up
543 setproctitle("-%s [pam]", getprogname());
544 waitpid(pid, &status, 0);
545 bail(NO_SLEEP_EXIT, 0);
549 * NOTICE: We are now in the child process!
553 * Add any environment variables the PAM modules may have set.
555 export_pam_environment();
558 * We're done with PAM now; our parent will deal with the rest.
564 * We don't need to be root anymore, so set the login name and
567 if (setlogin(username) != 0) {
568 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username);
569 bail(NO_SLEEP_EXIT, 1);
571 if (setusercontext(lc, pwd, pwd->pw_uid,
572 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) {
573 syslog(LOG_ERR, "setusercontext() failed - exiting");
577 (void)setenv("SHELL", pwd->pw_shell, 1);
578 (void)setenv("HOME", pwd->pw_dir, 1);
579 /* Overwrite "term" from login.conf(5) for any known TERM */
580 if (term == NULL && (tp = stypeof(tty)) != NULL)
581 (void)setenv("TERM", tp, 1);
583 (void)setenv("TERM", TERM_UNKNOWN, 0);
584 (void)setenv("LOGNAME", username, 1);
585 (void)setenv("USER", username, 1);
586 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0);
591 cw = login_getcapstr(lc, "welcome", NULL, NULL);
592 if (cw != NULL && access(cw, F_OK) == 0)
595 motd(_PATH_MOTDFILE);
597 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 &&
598 login_getcapbool(lc, "nocheckmail", 0) == 0) {
601 /* $MAIL may have been set by class. */
604 asprintf(&cx, "%s/%s",
605 _PATH_MAILDIR, pwd->pw_name);
607 if (cx && stat(cx, &st) == 0 && st.st_size != 0)
608 (void)printf("You have %smail.\n",
609 (st.st_mtime > st.st_atime) ? "new " : "");
610 if (getenv("MAIL") == NULL)
615 login_close(lc_user);
618 (void)signal(SIGALRM, SIG_DFL);
619 (void)signal(SIGQUIT, SIG_DFL);
620 (void)signal(SIGINT, SIG_DFL);
621 (void)signal(SIGTSTP, SIG_IGN);
624 * Login shells have a leading '-' in front of argv[0]
626 p = strrchr(pwd->pw_shell, '/');
627 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) {
628 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size",
630 errx(1, "shell exceeds maximum pathname size");
631 } else if (arg0 == NULL) {
632 err(1, "asprintf()");
635 execlp(shell, arg0, (char *)0);
644 * Attempt to authenticate the user using PAM. Returns 0 if the user is
645 * authenticated, or 1 if not authenticated. If some sort of PAM system
646 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
647 * function returns -1. This can be used as an indication that we should
648 * fall back to a different authentication mechanism.
653 const char *tmpl_user;
657 pam_err = pam_authenticate(pamh, pam_silent);
662 * With PAM we support the concept of a "template"
663 * user. The user enters a login name which is
664 * authenticated by PAM, usually via a remote service
665 * such as RADIUS or TACACS+. If authentication
666 * succeeds, a different but related "template" name
667 * is used for setting the credentials, shell, and
668 * home directory. The name the user enters need only
669 * exist on the remote authentication server, but the
670 * template name must be present in the local password
673 * This is supported by two various mechanisms in the
674 * individual modules. However, from the application's
675 * point of view, the template user is always passed
676 * back as a changed value of the PAM_USER item.
678 pam_err = pam_get_item(pamh, PAM_USER, &item);
679 if (pam_err == PAM_SUCCESS) {
680 tmpl_user = (const char *)item;
681 if (strcmp(username, tmpl_user) != 0)
682 pwd = getpwnam(tmpl_user);
684 pam_syslog("pam_get_item(PAM_USER)");
690 case PAM_USER_UNKNOWN:
696 pam_syslog("pam_authenticate()");
702 pam_err = pam_acct_mgmt(pamh, pam_silent);
706 case PAM_NEW_AUTHTOK_REQD:
707 pam_err = pam_chauthtok(pamh,
708 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK);
709 if (pam_err != PAM_SUCCESS) {
710 pam_syslog("pam_chauthtok()");
715 pam_syslog("pam_acct_mgmt()");
722 pam_end(pamh, pam_err);
729 * Export any environment variables PAM modules may have set
732 export_pam_environment(void)
737 pam_env = pam_getenvlist(pamh);
738 if (pam_env != NULL) {
739 for (pp = pam_env; *pp != NULL; pp++) {
747 * Perform sanity checks on an environment variable:
748 * - Make sure there is an '=' in the string.
749 * - Make sure the string doesn't run on too long.
750 * - Do not export certain variables. This list was taken from the
751 * Solaris pam_putenv(3) man page.
755 export(const char *s)
757 static const char *noexport[] = {
758 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH",
765 if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL)
767 if (strncmp(s, "LD_", 3) == 0)
769 for (pp = noexport; *pp != NULL; pp++) {
771 if (s[n] == '=' && strncmp(s, *pp, n) == 0)
775 (void)setenv(s, p + 1, 1);
784 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n");
789 * Prompt user and read login name from stdin.
797 nbuf = malloc(MAXLOGNAME);
801 (void)printf("%s", prompt);
802 for (p = nbuf; (ch = getchar()) != '\n'; ) {
805 bail(NO_SLEEP_EXIT, 0);
807 if (p < nbuf + MAXLOGNAME - 1)
813 if (nbuf[0] == '-') {
815 memmove(nbuf, nbuf + 1, strlen(nbuf));
817 pam_silent = PAM_SILENT;
823 * SIGINT handler for motd().
825 static volatile int motdinterrupt;
827 sigint(int signo __unused)
833 * Display the contents of a file (such as /etc/motd).
836 motd(const char *motdfile)
842 if ((f = fopen(motdfile, "r")) == NULL)
845 oldint = signal(SIGINT, sigint);
846 while ((ch = fgetc(f)) != EOF && !motdinterrupt)
848 signal(SIGINT, oldint);
849 if (ch != EOF || ferror(f)) {
858 * SIGALRM handler, to enforce login prompt timeout.
860 * XXX This can potentially confuse the hell out of PAM. We should
861 * XXX instead implement a conversation function that returns
862 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal
863 * XXX handler just set a flag.
866 timedout(int signo __unused)
869 longjmp(timeout_buf, signo);
879 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
880 failures, failures > 1 ? "S" : "", hostname);
881 syslog(LOG_AUTHPRIV|LOG_NOTICE,
882 "%d LOGIN FAILURE%s FROM %s, %s",
883 failures, failures > 1 ? "S" : "", hostname, name);
885 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
886 failures, failures > 1 ? "S" : "", tty);
887 syslog(LOG_AUTHPRIV|LOG_NOTICE,
888 "%d LOGIN FAILURE%s ON %s, %s",
889 failures, failures > 1 ? "S" : "", tty, name);
899 if (ttyid != NULL && *ttyid != '\0') {
900 t = getttynam(ttyid);
901 if (t != NULL && t->ty_type != NULL)
908 refused(const char *msg, const char *rtype, int lout)
912 printf("%s.\n", msg);
914 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s",
915 pwd->pw_name, rtype, hostname, tty);
917 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s",
918 pwd->pw_name, rtype, tty);
927 pam_syslog(const char *msg)
929 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err));
940 if (pam_session_established) {
941 pam_err = pam_close_session(pamh, 0);
942 if (pam_err != PAM_SUCCESS)
943 pam_syslog("pam_close_session()");
945 pam_session_established = 0;
946 if (pam_cred_established) {
947 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED);
948 if (pam_err != PAM_SUCCESS)
949 pam_syslog("pam_setcred()");
951 pam_cred_established = 0;
952 pam_end(pamh, pam_err);
958 * Exit, optionally after sleeping a few seconds
961 bail(int sec, int eval)