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/copyright.h>
57 #include <sys/param.h>
61 #include <sys/resource.h>
68 #include <login_cap.h>
79 #include <security/pam_appl.h>
80 #include <security/openpam.h>
83 #include "pathnames.h"
85 static int auth_pam(void);
86 static void bail(int, int);
87 static int export(const char *);
88 static void export_pam_environment(void);
89 static int motd(const char *);
90 static void badlogin(char *);
91 static char *getloginname(void);
92 static void pam_syslog(const char *);
93 static void pam_cleanup(void);
94 static void refused(const char *, const char *, int);
95 static const char *stypeof(char *);
96 static void sigint(int);
97 static void timedout(int);
98 static void usage(void);
100 #define TTYGRPNAME "tty" /* group to own ttys */
101 #define DEFAULT_BACKOFF 3
102 #define DEFAULT_RETRIES 10
103 #define DEFAULT_PROMPT "login: "
104 #define DEFAULT_PASSWD_PROMPT "Password:"
105 #define TERM_UNKNOWN "su"
106 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */
107 #define NO_SLEEP_EXIT 0
111 * This bounds the time given to login. Not a define so it can
112 * be patched on machines where it's too small.
114 static u_int timeout = 300;
116 /* Buffer for signal handling of timeout */
117 static jmp_buf timeout_buf;
122 static char *envinit[1]; /* empty environment list */
125 * Command line flags and arguments
127 static int fflag; /* -f: do not perform authentication */
128 static int hflag; /* -h: login from remote host */
129 static char *hostname; /* hostname from command line */
130 static int pflag; /* -p: preserve environment */
135 static char *username; /* user name */
136 static char *olduser; /* previous user name */
141 static char default_prompt[] = DEFAULT_PROMPT;
142 static const char *prompt;
143 static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT;
144 static const char *passwd_prompt;
151 static pam_handle_t *pamh = NULL;
152 static struct pam_conv pamc = { openpam_ttyconv, NULL };
154 static int pam_silent = PAM_SILENT;
155 static int pam_cred_established;
156 static int pam_session_established;
159 main(int argc, char *argv[])
163 int retries, backoff;
164 int ask, ch, cnt, quietlog, rootlogin, rval;
169 char tname[sizeof(_PATH_TTY) + 10];
172 const char *shell = NULL;
173 login_cap_t *lc = NULL;
174 login_cap_t *lc_user = NULL;
176 char auditsuccess = 1;
178 (void)signal(SIGQUIT, SIG_IGN);
179 (void)signal(SIGINT, SIG_IGN);
180 (void)signal(SIGHUP, SIG_IGN);
181 if (setjmp(timeout_buf)) {
184 (void)fprintf(stderr, "Login timed out after %d seconds\n",
186 bail(NO_SLEEP_EXIT, 0);
188 (void)signal(SIGALRM, timedout);
189 (void)alarm(timeout);
190 (void)setpriority(PRIO_PROCESS, 0, 0);
192 openlog("login", LOG_ODELAY, LOG_AUTH);
198 while ((ch = getopt(argc, argv, "fh:p")) != -1)
205 errx(1, "-h option: %s", strerror(EPERM));
206 if (strlen(optarg) >= MAXHOSTNAMELEN)
207 errx(1, "-h option: %s: exceeds maximum "
208 "hostname size", optarg);
218 syslog(LOG_ERR, "invalid flag %c", ch);
225 username = strdup(*argv);
226 if (username == NULL)
233 setproctitle("-%s", getprogname());
235 for (cnt = getdtablesize(); cnt > 2; cnt--)
241 ttyn = ttyname(STDIN_FILENO);
242 if (ttyn == NULL || *ttyn == '\0') {
243 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
246 if ((tty = strrchr(ttyn, '/')) != NULL)
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()");
295 au_login_fail("PAM Error", 1);
296 bail(NO_SLEEP_EXIT, 1);
298 pam_err = pam_set_item(pamh, PAM_TTY, tty);
299 if (pam_err != PAM_SUCCESS) {
300 pam_syslog("pam_set_item(PAM_TTY)");
301 au_login_fail("PAM Error", 1);
302 bail(NO_SLEEP_EXIT, 1);
304 pam_err = pam_set_item(pamh, PAM_RHOST, hostname);
305 if (pam_err != PAM_SUCCESS) {
306 pam_syslog("pam_set_item(PAM_RHOST)");
307 au_login_fail("PAM Error", 1);
308 bail(NO_SLEEP_EXIT, 1);
311 pwd = getpwnam(username);
312 if (pwd != NULL && pwd->pw_uid == 0)
316 * If the -f option was specified and the caller is
317 * root or the caller isn't changing their uid, don't
320 if (pwd != NULL && fflag &&
321 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) {
322 /* already authenticated */
324 auditsuccess = 0; /* opened a terminal window only */
327 (void)setpriority(PRIO_PROCESS, 0, -4);
329 (void)setpriority(PRIO_PROCESS, 0, 0);
332 if (pwd && rval == 0)
338 * We are not exiting here, but this corresponds to a failed
339 * login event, so set exitstatus to 1.
341 au_login_fail("Login incorrect", 1);
343 (void)printf("Login incorrect\n");
347 * Allow up to 'retry' (10) attempts, but start
348 * backing off after 'backoff' (3) attempts.
350 if (++cnt > backoff) {
351 if (cnt >= retries) {
355 sleep((u_int)((cnt - backoff) * 5));
359 /* committed to login -- turn off timeout */
360 (void)alarm((u_int)0);
361 (void)signal(SIGHUP, SIG_DFL);
365 /* Audit successful login. */
370 * Establish the login class.
372 lc = login_getpwclass(pwd);
373 lc_user = login_getuserclass(pwd);
375 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0)))
376 quietlog = login_getcapbool(lc, "hushlogin", 0);
379 * Switching needed for NFS with root access disabled.
381 * XXX: This change fails to modify the additional groups for the
382 * process, and as such, may restrict rights normally granted
383 * through those groups.
385 (void)setegid(pwd->pw_gid);
386 (void)seteuid(rootlogin ? 0 : pwd->pw_uid);
387 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) {
388 if (login_getcapbool(lc, "requirehome", 0))
389 refused("Home directory not available", "HOMEDIR", 1);
391 refused("Cannot find root directory", "ROOTDIR", 1);
392 if (!quietlog || *pwd->pw_dir)
393 printf("No home directory.\nLogging in with home = \"/\".\n");
394 pwd->pw_dir = strdup("/");
395 if (pwd->pw_dir == NULL) {
396 syslog(LOG_NOTICE, "strdup(): %m");
403 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
408 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell);
409 if (*pwd->pw_shell == '\0')
410 pwd->pw_shell = strdup(_PATH_BSHELL);
411 if (pwd->pw_shell == NULL) {
412 syslog(LOG_NOTICE, "strdup(): %m");
415 if (*shell == '\0') /* Not overridden */
416 shell = pwd->pw_shell;
417 if ((shell = strdup(shell)) == NULL) {
418 syslog(LOG_NOTICE, "strdup(): %m");
423 * Set device protections, depending on what terminal the
424 * user is logged in. This feature is used on Suns to give
425 * console users better privacy.
427 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
430 * Clear flags of the tty. None should be set, and when the
431 * user sets them otherwise, this can cause the chown to fail.
432 * Since it isn't clear that flags are useful on character
433 * devices, we just clear them.
435 * We don't log in the case of EOPNOTSUPP because dev might be
436 * on NFS, which doesn't support chflags.
438 * We don't log in the EROFS because that means that /dev is on
439 * a read only file system and we assume that the permissions there
442 if (ttyn != tname && chflags(ttyn, 0))
443 if (errno != EOPNOTSUPP && errno != EROFS)
444 syslog(LOG_ERR, "chflags(%s): %m", ttyn);
445 if (ttyn != tname && chown(ttyn, pwd->pw_uid,
446 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid))
448 syslog(LOG_ERR, "chown(%s): %m", ttyn);
451 * Exclude cons/vt/ptys only, assume dialup otherwise
452 * TODO: Make dialup tty determination a library call
453 * for consistency (finger etc.)
455 if (hflag && isdialuptty(tty))
456 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
460 * Syslog each successful login, so we don't have to watch
461 * hundreds of wtmp or lastlogin files.
464 syslog(LOG_INFO, "login from %s on %s as %s",
465 hostname, tty, pwd->pw_name);
467 syslog(LOG_INFO, "login on %s as %s",
472 * If fflag is on, assume caller/authenticator has logged root
475 if (rootlogin && fflag == 0) {
477 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
478 username, tty, hostname);
480 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s",
485 * Destroy environment unless user has requested its
486 * preservation - but preserve TERM in all cases
488 term = getenv("TERM");
492 setenv("TERM", term, 0);
495 * PAM modules might add supplementary groups during pam_setcred().
497 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
498 syslog(LOG_ERR, "setusercontext() failed - exiting");
499 bail(NO_SLEEP_EXIT, 1);
502 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED);
503 if (pam_err != PAM_SUCCESS) {
504 pam_syslog("pam_setcred()");
505 bail(NO_SLEEP_EXIT, 1);
507 pam_cred_established = 1;
509 pam_err = pam_open_session(pamh, pam_silent);
510 if (pam_err != PAM_SUCCESS) {
511 pam_syslog("pam_open_session()");
512 bail(NO_SLEEP_EXIT, 1);
514 pam_session_established = 1;
517 * We must fork() before setuid() because we need to call
518 * pam_close_session() as root.
523 } else if (pid != 0) {
525 * Parent: wait for child to finish, then clean up
529 setproctitle("-%s [pam]", getprogname());
530 waitpid(pid, &status, 0);
531 bail(NO_SLEEP_EXIT, 0);
535 * NOTICE: We are now in the child process!
539 * Add any environment variables the PAM modules may have set.
541 export_pam_environment();
544 * We're done with PAM now; our parent will deal with the rest.
550 * We don't need to be root anymore, so set the login name and
553 if (setlogin(username) != 0) {
554 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username);
555 bail(NO_SLEEP_EXIT, 1);
557 if (setusercontext(lc, pwd, pwd->pw_uid,
558 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) {
559 syslog(LOG_ERR, "setusercontext() failed - exiting");
563 (void)setenv("SHELL", pwd->pw_shell, 1);
564 (void)setenv("HOME", pwd->pw_dir, 1);
565 /* Overwrite "term" from login.conf(5) for any known TERM */
566 if (term == NULL && (tp = stypeof(tty)) != NULL)
567 (void)setenv("TERM", tp, 1);
569 (void)setenv("TERM", TERM_UNKNOWN, 0);
570 (void)setenv("LOGNAME", username, 1);
571 (void)setenv("USER", username, 1);
572 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0);
577 cw = login_getcapstr(lc, "copyright", NULL, NULL);
578 if (cw == NULL || motd(cw) == -1)
579 (void)printf("%s", copyright);
583 cw = login_getcapstr(lc, "welcome", NULL, NULL);
584 if (cw != NULL && access(cw, F_OK) == 0)
587 motd(_PATH_MOTDFILE);
589 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 &&
590 login_getcapbool(lc, "nocheckmail", 0) == 0) {
593 /* $MAIL may have been set by class. */
596 asprintf(&cx, "%s/%s",
597 _PATH_MAILDIR, pwd->pw_name);
599 if (cx && stat(cx, &st) == 0 && st.st_size != 0)
600 (void)printf("You have %smail.\n",
601 (st.st_mtime > st.st_atime) ? "new " : "");
602 if (getenv("MAIL") == NULL)
607 login_close(lc_user);
610 (void)signal(SIGALRM, SIG_DFL);
611 (void)signal(SIGQUIT, SIG_DFL);
612 (void)signal(SIGINT, SIG_DFL);
613 (void)signal(SIGTSTP, SIG_IGN);
616 * Login shells have a leading '-' in front of argv[0]
618 p = strrchr(pwd->pw_shell, '/');
619 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) {
620 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size",
622 errx(1, "shell exceeds maximum pathname size");
623 } else if (arg0 == NULL) {
624 err(1, "asprintf()");
627 execlp(shell, arg0, (char *)0);
636 * Attempt to authenticate the user using PAM. Returns 0 if the user is
637 * authenticated, or 1 if not authenticated. If some sort of PAM system
638 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
639 * function returns -1. This can be used as an indication that we should
640 * fall back to a different authentication mechanism.
645 const char *tmpl_user;
649 pam_err = pam_authenticate(pamh, pam_silent);
654 * With PAM we support the concept of a "template"
655 * user. The user enters a login name which is
656 * authenticated by PAM, usually via a remote service
657 * such as RADIUS or TACACS+. If authentication
658 * succeeds, a different but related "template" name
659 * is used for setting the credentials, shell, and
660 * home directory. The name the user enters need only
661 * exist on the remote authentication server, but the
662 * template name must be present in the local password
665 * This is supported by two various mechanisms in the
666 * individual modules. However, from the application's
667 * point of view, the template user is always passed
668 * back as a changed value of the PAM_USER item.
670 pam_err = pam_get_item(pamh, PAM_USER, &item);
671 if (pam_err == PAM_SUCCESS) {
672 tmpl_user = (const char *)item;
673 if (strcmp(username, tmpl_user) != 0)
674 pwd = getpwnam(tmpl_user);
676 pam_syslog("pam_get_item(PAM_USER)");
682 case PAM_USER_UNKNOWN:
688 pam_syslog("pam_authenticate()");
694 pam_err = pam_acct_mgmt(pamh, pam_silent);
698 case PAM_NEW_AUTHTOK_REQD:
699 pam_err = pam_chauthtok(pamh,
700 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK);
701 if (pam_err != PAM_SUCCESS) {
702 pam_syslog("pam_chauthtok()");
707 pam_syslog("pam_acct_mgmt()");
714 pam_end(pamh, pam_err);
721 * Export any environment variables PAM modules may have set
724 export_pam_environment()
729 pam_env = pam_getenvlist(pamh);
730 if (pam_env != NULL) {
731 for (pp = pam_env; *pp != NULL; pp++) {
739 * Perform sanity checks on an environment variable:
740 * - Make sure there is an '=' in the string.
741 * - Make sure the string doesn't run on too long.
742 * - Do not export certain variables. This list was taken from the
743 * Solaris pam_putenv(3) man page.
747 export(const char *s)
749 static const char *noexport[] = {
750 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH",
756 if (strlen(s) > 1024 || strchr(s, '=') == NULL)
758 if (strncmp(s, "LD_", 3) == 0)
760 for (pp = noexport; *pp != NULL; pp++) {
762 if (s[n] == '=' && strncmp(s, *pp, n) == 0)
773 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n");
778 * Prompt user and read login name from stdin.
786 nbuf = malloc(MAXLOGNAME);
790 (void)printf("%s", prompt);
791 for (p = nbuf; (ch = getchar()) != '\n'; ) {
794 bail(NO_SLEEP_EXIT, 0);
796 if (p < nbuf + MAXLOGNAME - 1)
802 if (nbuf[0] == '-') {
804 memmove(nbuf, nbuf + 1, strlen(nbuf));
806 pam_silent = PAM_SILENT;
812 * SIGINT handler for motd().
814 static volatile int motdinterrupt;
816 sigint(int signo __unused)
822 * Display the contents of a file (such as /etc/motd).
825 motd(const char *motdfile)
831 if ((f = fopen(motdfile, "r")) == NULL)
834 oldint = signal(SIGINT, sigint);
835 while ((ch = fgetc(f)) != EOF && !motdinterrupt)
837 signal(SIGINT, oldint);
838 if (ch != EOF || ferror(f)) {
847 * SIGALRM handler, to enforce login prompt timeout.
849 * XXX This can potentially confuse the hell out of PAM. We should
850 * XXX instead implement a conversation function that returns
851 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal
852 * XXX handler just set a flag.
855 timedout(int signo __unused)
858 longjmp(timeout_buf, signo);
868 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
869 failures, failures > 1 ? "S" : "", hostname);
870 syslog(LOG_AUTHPRIV|LOG_NOTICE,
871 "%d LOGIN FAILURE%s FROM %s, %s",
872 failures, failures > 1 ? "S" : "", hostname, name);
874 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
875 failures, failures > 1 ? "S" : "", tty);
876 syslog(LOG_AUTHPRIV|LOG_NOTICE,
877 "%d LOGIN FAILURE%s ON %s, %s",
878 failures, failures > 1 ? "S" : "", tty, name);
888 if (ttyid != NULL && *ttyid != '\0') {
889 t = getttynam(ttyid);
890 if (t != NULL && t->ty_type != NULL)
897 refused(const char *msg, const char *rtype, int lout)
901 printf("%s.\n", msg);
903 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s",
904 pwd->pw_name, rtype, hostname, tty);
906 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s",
907 pwd->pw_name, rtype, tty);
916 pam_syslog(const char *msg)
918 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err));
929 if (pam_session_established) {
930 pam_err = pam_close_session(pamh, 0);
931 if (pam_err != PAM_SUCCESS)
932 pam_syslog("pam_close_session()");
934 pam_session_established = 0;
935 if (pam_cred_established) {
936 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED);
937 if (pam_err != PAM_SUCCESS)
938 pam_syslog("pam_setcred()");
940 pam_cred_established = 0;
941 pam_end(pamh, pam_err);
947 * Exit, optionally after sleeping a few seconds
950 bail(int sec, int eval)