49
50/*
51 * login [ name ]
52 * login -h hostname (for telnetd, etc.)
53 * login -f name (for pre-authenticated login: datakit, xterm, etc.)
54 */
55
56#include <sys/copyright.h>
57#include <sys/param.h>
58#include <sys/file.h>
59#include <sys/stat.h>
60#include <sys/time.h>
61#include <sys/resource.h>
62#include <sys/wait.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 <pwd.h>
70#include <setjmp.h>
71#include <signal.h>
72#include <stdio.h>
73#include <stdlib.h>
74#include <string.h>
75#include <syslog.h>
76#include <ttyent.h>
77#include <unistd.h>
78
79#include <security/pam_appl.h>
80#include <security/openpam.h>
81
82#include "login.h"
83#include "pathnames.h"
84
85static int auth_pam(void);
86static void bail(int, int);
87static int export(const char *);
88static void export_pam_environment(void);
89static int motd(const char *);
90static void badlogin(char *);
91static char *getloginname(void);
92static void pam_syslog(const char *);
93static void pam_cleanup(void);
94static void refused(const char *, const char *, int);
95static const char *stypeof(char *);
96static void sigint(int);
97static void timedout(int);
98static void usage(void);
99
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
108#define SLEEP_EXIT 5
109
110/*
111 * This bounds the time given to login. Not a define so it can
112 * be patched on machines where it's too small.
113 */
114static u_int timeout = 300;
115
116/* Buffer for signal handling of timeout */
117static jmp_buf timeout_buf;
118
119struct passwd *pwd;
120static int failures;
121
122static char *envinit[1]; /* empty environment list */
123
124/*
125 * Command line flags and arguments
126 */
127static int fflag; /* -f: do not perform authentication */
128static int hflag; /* -h: login from remote host */
129static char *hostname; /* hostname from command line */
130static int pflag; /* -p: preserve environment */
131
132/*
133 * User name
134 */
135static char *username; /* user name */
136static char *olduser; /* previous user name */
137
138/*
139 * Prompts
140 */
141static char default_prompt[] = DEFAULT_PROMPT;
142static const char *prompt;
143static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT;
144static const char *passwd_prompt;
145
146static char *tty;
147
148/*
149 * PAM data
150 */
151static pam_handle_t *pamh = NULL;
152static struct pam_conv pamc = { openpam_ttyconv, NULL };
153static int pam_err;
154static int pam_silent = PAM_SILENT;
155static int pam_cred_established;
156static int pam_session_established;
157
158int
159main(int argc, char *argv[])
160{
161 struct group *gr;
162 struct stat st;
163 int retries, backoff;
164 int ask, ch, cnt, quietlog, rootlogin, rval;
165 uid_t uid, euid;
166 gid_t egid;
167 char *term;
168 char *p, *ttyn;
169 char tname[sizeof(_PATH_TTY) + 10];
170 char *arg0;
171 const char *tp;
172 const char *shell = NULL;
173 login_cap_t *lc = NULL;
174 login_cap_t *lc_user = NULL;
175 pid_t pid;
176#ifdef USE_BSM_AUDIT
177 char auditsuccess = 1;
178#endif
179
180 (void)signal(SIGQUIT, SIG_IGN);
181 (void)signal(SIGINT, SIG_IGN);
182 (void)signal(SIGHUP, SIG_IGN);
183 if (setjmp(timeout_buf)) {
184 if (failures)
185 badlogin(username);
186 (void)fprintf(stderr, "Login timed out after %d seconds\n",
187 timeout);
188 bail(NO_SLEEP_EXIT, 0);
189 }
190 (void)signal(SIGALRM, timedout);
191 (void)alarm(timeout);
192 (void)setpriority(PRIO_PROCESS, 0, 0);
193
194 openlog("login", LOG_ODELAY, LOG_AUTH);
195
196 uid = getuid();
197 euid = geteuid();
198 egid = getegid();
199
200 while ((ch = getopt(argc, argv, "fh:p")) != -1)
201 switch (ch) {
202 case 'f':
203 fflag = 1;
204 break;
205 case 'h':
206 if (uid != 0)
207 errx(1, "-h option: %s", strerror(EPERM));
208 if (strlen(optarg) >= MAXHOSTNAMELEN)
209 errx(1, "-h option: %s: exceeds maximum "
210 "hostname size", optarg);
211 hflag = 1;
212 hostname = optarg;
213 break;
214 case 'p':
215 pflag = 1;
216 break;
217 case '?':
218 default:
219 if (uid == 0)
220 syslog(LOG_ERR, "invalid flag %c", ch);
221 usage();
222 }
223 argc -= optind;
224 argv += optind;
225
226 if (argc > 0) {
227 username = strdup(*argv);
228 if (username == NULL)
229 err(1, "strdup()");
230 ask = 0;
231 } else {
232 ask = 1;
233 }
234
235 setproctitle("-%s", getprogname());
236
237 for (cnt = getdtablesize(); cnt > 2; cnt--)
238 (void)close(cnt);
239
240 /*
241 * Get current TTY
242 */
243 ttyn = ttyname(STDIN_FILENO);
244 if (ttyn == NULL || *ttyn == '\0') {
245 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
246 ttyn = tname;
247 }
248 if ((tty = strrchr(ttyn, '/')) != NULL)
249 ++tty;
250 else
251 tty = ttyn;
252
253 /*
254 * Get "login-retries" & "login-backoff" from default class
255 */
256 lc = login_getclass(NULL);
257 prompt = login_getcapstr(lc, "login_prompt",
258 default_prompt, default_prompt);
259 passwd_prompt = login_getcapstr(lc, "passwd_prompt",
260 default_passwd_prompt, default_passwd_prompt);
261 retries = login_getcapnum(lc, "login-retries",
262 DEFAULT_RETRIES, DEFAULT_RETRIES);
263 backoff = login_getcapnum(lc, "login-backoff",
264 DEFAULT_BACKOFF, DEFAULT_BACKOFF);
265 login_close(lc);
266 lc = NULL;
267
268 /*
269 * Try to authenticate the user until we succeed or time out.
270 */
271 for (cnt = 0;; ask = 1) {
272 if (ask) {
273 fflag = 0;
274 if (olduser != NULL)
275 free(olduser);
276 olduser = username;
277 username = getloginname();
278 }
279 rootlogin = 0;
280
281 /*
282 * Note if trying multiple user names; log failures for
283 * previous user name, but don't bother logging one failure
284 * for nonexistent name (mistyped username).
285 */
286 if (failures && strcmp(olduser, username) != 0) {
287 if (failures > (pwd ? 0 : 1))
288 badlogin(olduser);
289 }
290
291 /*
292 * Load the PAM policy and set some variables
293 */
294 pam_err = pam_start("login", username, &pamc, &pamh);
295 if (pam_err != PAM_SUCCESS) {
296 pam_syslog("pam_start()");
297#ifdef USE_BSM_AUDIT
298 au_login_fail("PAM Error", 1);
299#endif
300 bail(NO_SLEEP_EXIT, 1);
301 }
302 pam_err = pam_set_item(pamh, PAM_TTY, tty);
303 if (pam_err != PAM_SUCCESS) {
304 pam_syslog("pam_set_item(PAM_TTY)");
305#ifdef USE_BSM_AUDIT
306 au_login_fail("PAM Error", 1);
307#endif
308 bail(NO_SLEEP_EXIT, 1);
309 }
310 pam_err = pam_set_item(pamh, PAM_RHOST, hostname);
311 if (pam_err != PAM_SUCCESS) {
312 pam_syslog("pam_set_item(PAM_RHOST)");
313#ifdef USE_BSM_AUDIT
314 au_login_fail("PAM Error", 1);
315#endif
316 bail(NO_SLEEP_EXIT, 1);
317 }
318
319 pwd = getpwnam(username);
320 if (pwd != NULL && pwd->pw_uid == 0)
321 rootlogin = 1;
322
323 /*
324 * If the -f option was specified and the caller is
325 * root or the caller isn't changing their uid, don't
326 * authenticate.
327 */
328 if (pwd != NULL && fflag &&
329 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) {
330 /* already authenticated */
331 rval = 0;
332#ifdef USE_BSM_AUDIT
333 auditsuccess = 0; /* opened a terminal window only */
334#endif
335 } else {
336 fflag = 0;
337 (void)setpriority(PRIO_PROCESS, 0, -4);
338 rval = auth_pam();
339 (void)setpriority(PRIO_PROCESS, 0, 0);
340 }
341
342 if (pwd && rval == 0)
343 break;
344
345 pam_cleanup();
346
347 /*
348 * We are not exiting here, but this corresponds to a failed
349 * login event, so set exitstatus to 1.
350 */
351#ifdef USE_BSM_AUDIT
352 au_login_fail("Login incorrect", 1);
353#endif
354
355 (void)printf("Login incorrect\n");
356 failures++;
357
358 pwd = NULL;
359
360 /*
361 * Allow up to 'retry' (10) attempts, but start
362 * backing off after 'backoff' (3) attempts.
363 */
364 if (++cnt > backoff) {
365 if (cnt >= retries) {
366 badlogin(username);
367 bail(SLEEP_EXIT, 1);
368 }
369 sleep((u_int)((cnt - backoff) * 5));
370 }
371 }
372
373 /* committed to login -- turn off timeout */
374 (void)alarm((u_int)0);
375 (void)signal(SIGHUP, SIG_DFL);
376
377 endpwent();
378
379#ifdef USE_BSM_AUDIT
380 /* Audit successful login. */
381 if (auditsuccess)
382 au_login_success();
383#endif
384
385 /*
386 * Establish the login class.
387 */
388 lc = login_getpwclass(pwd);
389 lc_user = login_getuserclass(pwd);
390
391 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0)))
392 quietlog = login_getcapbool(lc, "hushlogin", 0);
393
394 /*
395 * Switching needed for NFS with root access disabled.
396 *
397 * XXX: This change fails to modify the additional groups for the
398 * process, and as such, may restrict rights normally granted
399 * through those groups.
400 */
401 (void)setegid(pwd->pw_gid);
402 (void)seteuid(rootlogin ? 0 : pwd->pw_uid);
403 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) {
404 if (login_getcapbool(lc, "requirehome", 0))
405 refused("Home directory not available", "HOMEDIR", 1);
406 if (chdir("/") < 0)
407 refused("Cannot find root directory", "ROOTDIR", 1);
408 if (!quietlog || *pwd->pw_dir)
409 printf("No home directory.\nLogging in with home = \"/\".\n");
410 pwd->pw_dir = strdup("/");
411 if (pwd->pw_dir == NULL) {
412 syslog(LOG_NOTICE, "strdup(): %m");
413 bail(SLEEP_EXIT, 1);
414 }
415 }
416 (void)seteuid(euid);
417 (void)setegid(egid);
418 if (!quietlog) {
419 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
420 if (!quietlog)
421 pam_silent = 0;
422 }
423
424 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell);
425 if (*pwd->pw_shell == '\0')
426 pwd->pw_shell = strdup(_PATH_BSHELL);
427 if (pwd->pw_shell == NULL) {
428 syslog(LOG_NOTICE, "strdup(): %m");
429 bail(SLEEP_EXIT, 1);
430 }
431 if (*shell == '\0') /* Not overridden */
432 shell = pwd->pw_shell;
433 if ((shell = strdup(shell)) == NULL) {
434 syslog(LOG_NOTICE, "strdup(): %m");
435 bail(SLEEP_EXIT, 1);
436 }
437
438 /*
439 * Set device protections, depending on what terminal the
440 * user is logged in. This feature is used on Suns to give
441 * console users better privacy.
442 */
443 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
444
445 /*
446 * Clear flags of the tty. None should be set, and when the
447 * user sets them otherwise, this can cause the chown to fail.
448 * Since it isn't clear that flags are useful on character
449 * devices, we just clear them.
450 *
451 * We don't log in the case of EOPNOTSUPP because dev might be
452 * on NFS, which doesn't support chflags.
453 *
454 * We don't log in the EROFS because that means that /dev is on
455 * a read only file system and we assume that the permissions there
456 * are sane.
457 */
458 if (ttyn != tname && chflags(ttyn, 0))
459 if (errno != EOPNOTSUPP && errno != EROFS)
460 syslog(LOG_ERR, "chflags(%s): %m", ttyn);
461 if (ttyn != tname && chown(ttyn, pwd->pw_uid,
462 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid))
463 if (errno != EROFS)
464 syslog(LOG_ERR, "chown(%s): %m", ttyn);
465
466 /*
467 * Exclude cons/vt/ptys only, assume dialup otherwise
468 * TODO: Make dialup tty determination a library call
469 * for consistency (finger etc.)
470 */
471 if (hflag && isdialuptty(tty))
472 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
473
474#ifdef LOGALL
475 /*
476 * Syslog each successful login, so we don't have to watch
477 * hundreds of wtmp or lastlogin files.
478 */
479 if (hflag)
480 syslog(LOG_INFO, "login from %s on %s as %s",
481 hostname, tty, pwd->pw_name);
482 else
483 syslog(LOG_INFO, "login on %s as %s",
484 tty, pwd->pw_name);
485#endif
486
487 /*
488 * If fflag is on, assume caller/authenticator has logged root
489 * login.
490 */
491 if (rootlogin && fflag == 0) {
492 if (hflag)
493 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
494 username, tty, hostname);
495 else
496 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s",
497 username, tty);
498 }
499
500 /*
501 * Destroy environment unless user has requested its
502 * preservation - but preserve TERM in all cases
503 */
504 term = getenv("TERM");
505 if (!pflag)
506 environ = envinit;
507 if (term != NULL)
508 setenv("TERM", term, 0);
509
510 /*
511 * PAM modules might add supplementary groups during pam_setcred().
512 */
513 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
514 syslog(LOG_ERR, "setusercontext() failed - exiting");
515 bail(NO_SLEEP_EXIT, 1);
516 }
517
518 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED);
519 if (pam_err != PAM_SUCCESS) {
520 pam_syslog("pam_setcred()");
521 bail(NO_SLEEP_EXIT, 1);
522 }
523 pam_cred_established = 1;
524
525 pam_err = pam_open_session(pamh, pam_silent);
526 if (pam_err != PAM_SUCCESS) {
527 pam_syslog("pam_open_session()");
528 bail(NO_SLEEP_EXIT, 1);
529 }
530 pam_session_established = 1;
531
532 /*
533 * We must fork() before setuid() because we need to call
534 * pam_close_session() as root.
535 */
536 pid = fork();
537 if (pid < 0) {
538 err(1, "fork");
539 } else if (pid != 0) {
540 /*
541 * Parent: wait for child to finish, then clean up
542 * session.
543 */
544 int status;
545 setproctitle("-%s [pam]", getprogname());
546 waitpid(pid, &status, 0);
547 bail(NO_SLEEP_EXIT, 0);
548 }
549
550 /*
551 * NOTICE: We are now in the child process!
552 */
553
554 /*
555 * Add any environment variables the PAM modules may have set.
556 */
557 export_pam_environment();
558
559 /*
560 * We're done with PAM now; our parent will deal with the rest.
561 */
562 pam_end(pamh, 0);
563 pamh = NULL;
564
565 /*
566 * We don't need to be root anymore, so set the login name and
567 * the UID.
568 */
569 if (setlogin(username) != 0) {
570 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username);
571 bail(NO_SLEEP_EXIT, 1);
572 }
573 if (setusercontext(lc, pwd, pwd->pw_uid,
574 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) {
575 syslog(LOG_ERR, "setusercontext() failed - exiting");
576 exit(1);
577 }
578
579 (void)setenv("SHELL", pwd->pw_shell, 1);
580 (void)setenv("HOME", pwd->pw_dir, 1);
581 /* Overwrite "term" from login.conf(5) for any known TERM */
582 if (term == NULL && (tp = stypeof(tty)) != NULL)
583 (void)setenv("TERM", tp, 1);
584 else
585 (void)setenv("TERM", TERM_UNKNOWN, 0);
586 (void)setenv("LOGNAME", username, 1);
587 (void)setenv("USER", username, 1);
588 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0);
589
590 if (!quietlog) {
591 const char *cw;
592
593 cw = login_getcapstr(lc, "copyright", NULL, NULL);
594 if (cw == NULL || motd(cw) == -1)
595 (void)printf("%s", copyright);
596
597 (void)printf("\n");
598
599 cw = login_getcapstr(lc, "welcome", NULL, NULL);
600 if (cw != NULL && access(cw, F_OK) == 0)
601 motd(cw);
602 else
603 motd(_PATH_MOTDFILE);
604
605 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 &&
606 login_getcapbool(lc, "nocheckmail", 0) == 0) {
607 char *cx;
608
609 /* $MAIL may have been set by class. */
610 cx = getenv("MAIL");
611 if (cx == NULL) {
612 asprintf(&cx, "%s/%s",
613 _PATH_MAILDIR, pwd->pw_name);
614 }
615 if (cx && stat(cx, &st) == 0 && st.st_size != 0)
616 (void)printf("You have %smail.\n",
617 (st.st_mtime > st.st_atime) ? "new " : "");
618 if (getenv("MAIL") == NULL)
619 free(cx);
620 }
621 }
622
623 login_close(lc_user);
624 login_close(lc);
625
626 (void)signal(SIGALRM, SIG_DFL);
627 (void)signal(SIGQUIT, SIG_DFL);
628 (void)signal(SIGINT, SIG_DFL);
629 (void)signal(SIGTSTP, SIG_IGN);
630
631 /*
632 * Login shells have a leading '-' in front of argv[0]
633 */
634 p = strrchr(pwd->pw_shell, '/');
635 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) {
636 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size",
637 username);
638 errx(1, "shell exceeds maximum pathname size");
639 } else if (arg0 == NULL) {
640 err(1, "asprintf()");
641 }
642
643 execlp(shell, arg0, (char *)0);
644 err(1, "%s", shell);
645
646 /*
647 * That's it, folks!
648 */
649}
650
651/*
652 * Attempt to authenticate the user using PAM. Returns 0 if the user is
653 * authenticated, or 1 if not authenticated. If some sort of PAM system
654 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
655 * function returns -1. This can be used as an indication that we should
656 * fall back to a different authentication mechanism.
657 */
658static int
659auth_pam(void)
660{
661 const char *tmpl_user;
662 const void *item;
663 int rval;
664
665 pam_err = pam_authenticate(pamh, pam_silent);
666 switch (pam_err) {
667
668 case PAM_SUCCESS:
669 /*
670 * With PAM we support the concept of a "template"
671 * user. The user enters a login name which is
672 * authenticated by PAM, usually via a remote service
673 * such as RADIUS or TACACS+. If authentication
674 * succeeds, a different but related "template" name
675 * is used for setting the credentials, shell, and
676 * home directory. The name the user enters need only
677 * exist on the remote authentication server, but the
678 * template name must be present in the local password
679 * database.
680 *
681 * This is supported by two various mechanisms in the
682 * individual modules. However, from the application's
683 * point of view, the template user is always passed
684 * back as a changed value of the PAM_USER item.
685 */
686 pam_err = pam_get_item(pamh, PAM_USER, &item);
687 if (pam_err == PAM_SUCCESS) {
688 tmpl_user = (const char *)item;
689 if (strcmp(username, tmpl_user) != 0)
690 pwd = getpwnam(tmpl_user);
691 } else {
692 pam_syslog("pam_get_item(PAM_USER)");
693 }
694 rval = 0;
695 break;
696
697 case PAM_AUTH_ERR:
698 case PAM_USER_UNKNOWN:
699 case PAM_MAXTRIES:
700 rval = 1;
701 break;
702
703 default:
704 pam_syslog("pam_authenticate()");
705 rval = -1;
706 break;
707 }
708
709 if (rval == 0) {
710 pam_err = pam_acct_mgmt(pamh, pam_silent);
711 switch (pam_err) {
712 case PAM_SUCCESS:
713 break;
714 case PAM_NEW_AUTHTOK_REQD:
715 pam_err = pam_chauthtok(pamh,
716 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK);
717 if (pam_err != PAM_SUCCESS) {
718 pam_syslog("pam_chauthtok()");
719 rval = 1;
720 }
721 break;
722 default:
723 pam_syslog("pam_acct_mgmt()");
724 rval = 1;
725 break;
726 }
727 }
728
729 if (rval != 0) {
730 pam_end(pamh, pam_err);
731 pamh = NULL;
732 }
733 return (rval);
734}
735
736/*
737 * Export any environment variables PAM modules may have set
738 */
739static void
740export_pam_environment()
741{
742 char **pam_env;
743 char **pp;
744
745 pam_env = pam_getenvlist(pamh);
746 if (pam_env != NULL) {
747 for (pp = pam_env; *pp != NULL; pp++) {
|
750 }
751 }
752}
753
754/*
755 * Perform sanity checks on an environment variable:
756 * - Make sure there is an '=' in the string.
757 * - Make sure the string doesn't run on too long.
758 * - Do not export certain variables. This list was taken from the
759 * Solaris pam_putenv(3) man page.
760 * Then export it.
761 */
762static int
763export(const char *s)
764{
765 static const char *noexport[] = {
766 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH",
767 "IFS", "PATH", NULL
768 };
769 const char **pp;
770 size_t n;
771
772 if (strlen(s) > 1024 || strchr(s, '=') == NULL)
773 return (0);
774 if (strncmp(s, "LD_", 3) == 0)
775 return (0);
776 for (pp = noexport; *pp != NULL; pp++) {
777 n = strlen(*pp);
778 if (s[n] == '=' && strncmp(s, *pp, n) == 0)
779 return (0);
780 }
781 (void)putenv(s);
782 return (1);
783}
784
785static void
786usage()
787{
788
789 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n");
790 exit(1);
791}
792
793/*
794 * Prompt user and read login name from stdin.
795 */
796static char *
797getloginname()
798{
799 char *nbuf, *p;
800 int ch;
801
802 nbuf = malloc(MAXLOGNAME);
803 if (nbuf == NULL)
804 err(1, "malloc()");
805 do {
806 (void)printf("%s", prompt);
807 for (p = nbuf; (ch = getchar()) != '\n'; ) {
808 if (ch == EOF) {
809 badlogin(username);
810 bail(NO_SLEEP_EXIT, 0);
811 }
812 if (p < nbuf + MAXLOGNAME - 1)
813 *p++ = ch;
814 }
815 } while (p == nbuf);
816
817 *p = '\0';
818 if (nbuf[0] == '-') {
819 pam_silent = 0;
820 memmove(nbuf, nbuf + 1, strlen(nbuf));
821 } else {
822 pam_silent = PAM_SILENT;
823 }
824 return nbuf;
825}
826
827/*
828 * SIGINT handler for motd().
829 */
830static volatile int motdinterrupt;
831static void
832sigint(int signo __unused)
833{
834 motdinterrupt = 1;
835}
836
837/*
838 * Display the contents of a file (such as /etc/motd).
839 */
840static int
841motd(const char *motdfile)
842{
843 sig_t oldint;
844 FILE *f;
845 int ch;
846
847 if ((f = fopen(motdfile, "r")) == NULL)
848 return (-1);
849 motdinterrupt = 0;
850 oldint = signal(SIGINT, sigint);
851 while ((ch = fgetc(f)) != EOF && !motdinterrupt)
852 putchar(ch);
853 signal(SIGINT, oldint);
854 if (ch != EOF || ferror(f)) {
855 fclose(f);
856 return (-1);
857 }
858 fclose(f);
859 return (0);
860}
861
862/*
863 * SIGALRM handler, to enforce login prompt timeout.
864 *
865 * XXX This can potentially confuse the hell out of PAM. We should
866 * XXX instead implement a conversation function that returns
867 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal
868 * XXX handler just set a flag.
869 */
870static void
871timedout(int signo __unused)
872{
873
874 longjmp(timeout_buf, signo);
875}
876
877static void
878badlogin(char *name)
879{
880
881 if (failures == 0)
882 return;
883 if (hflag) {
884 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
885 failures, failures > 1 ? "S" : "", hostname);
886 syslog(LOG_AUTHPRIV|LOG_NOTICE,
887 "%d LOGIN FAILURE%s FROM %s, %s",
888 failures, failures > 1 ? "S" : "", hostname, name);
889 } else {
890 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
891 failures, failures > 1 ? "S" : "", tty);
892 syslog(LOG_AUTHPRIV|LOG_NOTICE,
893 "%d LOGIN FAILURE%s ON %s, %s",
894 failures, failures > 1 ? "S" : "", tty, name);
895 }
896 failures = 0;
897}
898
899const char *
900stypeof(char *ttyid)
901{
902 struct ttyent *t;
903
904 if (ttyid != NULL && *ttyid != '\0') {
905 t = getttynam(ttyid);
906 if (t != NULL && t->ty_type != NULL)
907 return (t->ty_type);
908 }
909 return (NULL);
910}
911
912static void
913refused(const char *msg, const char *rtype, int lout)
914{
915
916 if (msg != NULL)
917 printf("%s.\n", msg);
918 if (hflag)
919 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s",
920 pwd->pw_name, rtype, hostname, tty);
921 else
922 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s",
923 pwd->pw_name, rtype, tty);
924 if (lout)
925 bail(SLEEP_EXIT, 1);
926}
927
928/*
929 * Log a PAM error
930 */
931static void
932pam_syslog(const char *msg)
933{
934 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err));
935}
936
937/*
938 * Shut down PAM
939 */
940static void
941pam_cleanup()
942{
943
944 if (pamh != NULL) {
945 if (pam_session_established) {
946 pam_err = pam_close_session(pamh, 0);
947 if (pam_err != PAM_SUCCESS)
948 pam_syslog("pam_close_session()");
949 }
950 pam_session_established = 0;
951 if (pam_cred_established) {
952 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED);
953 if (pam_err != PAM_SUCCESS)
954 pam_syslog("pam_setcred()");
955 }
956 pam_cred_established = 0;
957 pam_end(pamh, pam_err);
958 pamh = NULL;
959 }
960}
961
962/*
963 * Exit, optionally after sleeping a few seconds
964 */
965void
966bail(int sec, int eval)
967{
968
969 pam_cleanup();
970#ifdef USE_BSM_AUDIT
971 if (pwd != NULL)
972 audit_logout();
973#endif
974 (void)sleep(sec);
975 exit(eval);
976}
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