4 * This program is derived from 4.3 BSD software and is subject to the
5 * copyright notice below.
7 * Copyright (C) 2011 Karel Zak <kzak@redhat.com>
8 * Rewritten to PAM-only version.
10 * Michael Glad (glad@daimi.dk)
11 * Computer Science Department, Aarhus University, Denmark
14 * Copyright (c) 1980, 1987, 1988 The Regents of the University of California.
15 * All rights reserved.
17 * Redistribution and use in source and binary forms are permitted
18 * provided that the above copyright notice and this paragraph are
19 * duplicated in all such forms and that any documentation,
20 * advertising materials, and other materials related to such
21 * distribution and use acknowledge that the software was developed
22 * by the University of California, Berkeley. The name of the
23 * University may not be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
27 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
29 #include <sys/param.h>
38 #include <sys/resource.h>
42 #include <sys/ioctl.h>
53 #include <sys/syslog.h>
54 #ifdef HAVE_LINUX_MAJOR_H
55 # include <linux/major.h>
58 #include <security/pam_appl.h>
59 #ifdef HAVE_SECURITY_PAM_MISC_H
60 # include <security/pam_misc.h>
61 #elif defined(HAVE_SECURITY_OPENPAM_H)
62 # include <security/openpam.h>
64 #include <sys/sendfile.h>
67 # include <libaudit.h>
71 #include "setproctitle.h"
72 #include "pathnames.h"
78 #include "fileutils.h"
81 #include "logindefs.h"
83 #define is_pam_failure(_rc) ((_rc) != PAM_SUCCESS)
85 #define LOGIN_MAX_TRIES 3
86 #define LOGIN_EXIT_TIMEOUT 5
87 #define LOGIN_TIMEOUT 60
90 # define TTY_MODE 0620
92 # define TTY_MODE 0600
95 #define TTYGRPNAME "tty" /* name of group to own ttys */
96 #define VCS_PATH_MAX 64
99 * Login control struct
101 struct login_context
{
102 const char *tty_path
; /* ttyname() return value */
103 const char *tty_name
; /* tty_path without /dev prefix */
104 const char *tty_number
; /* end of the tty_path */
105 mode_t tty_mode
; /* chmod() mode */
107 char *username
; /* from command line or PAM */
109 struct passwd
*pwd
; /* user info */
111 pam_handle_t
*pamh
; /* PAM handler */
112 struct pam_conv conv
; /* PAM conversation */
114 #ifdef LOGIN_CHOWN_VCS
115 char vcsn
[VCS_PATH_MAX
]; /* virtual console name */
116 char vcsan
[VCS_PATH_MAX
];
119 char *thishost
; /* this machine */
120 char *thisdomain
; /* this machine's domain */
121 char *hostname
; /* remote machine */
122 char hostaddress
[16]; /* remote address */
125 int quiet
; /* 1 if hush file exists */
127 unsigned int remote
:1, /* login -h */
128 nohost
:1, /* login -H */
129 noauth
:1, /* login -f */
130 keep_env
:1; /* login -p */
134 * This bounds the time given to login. Not a define, so it can
135 * be patched on machines where it's too small.
137 static unsigned int timeout
= LOGIN_TIMEOUT
;
138 static int child_pid
= 0;
139 static volatile int got_sig
= 0;
141 #ifdef LOGIN_CHOWN_VCS
142 /* true if the filedescriptor fd is a console tty, very Linux specific */
143 static int is_consoletty(int fd
)
147 if ((fstat(fd
, &stb
) >= 0)
148 && (major(stb
.st_rdev
) == TTY_MAJOR
)
149 && (minor(stb
.st_rdev
) < 64)) {
158 * Robert Ambrose writes:
159 * A couple of my users have a problem with login processes hanging around
160 * soaking up pts's. What they seem to hung up on is trying to write out the
161 * message 'Login timed out after %d seconds' when the connection has already
163 * What I did was add a second timeout while trying to write the message, so
164 * the process just exits if the second timeout expires.
166 static void __attribute__ ((__noreturn__
))
167 timedout2(int sig
__attribute__ ((__unused__
)))
174 tcsetattr(0, TCSANOW
, &ti
);
175 exit(EXIT_SUCCESS
); /* %% */
178 static void timedout(int sig
__attribute__ ((__unused__
)))
180 signal(SIGALRM
, timedout2
);
182 /* TRANSLATORS: The standard value for %u is 60. */
183 warnx(_("timed out after %u seconds"), timeout
);
184 signal(SIGALRM
, SIG_IGN
);
190 * This handler allows to inform a shell about signals to login. If you have
191 * (root) permissions, you can kill all login children by one signal to the
194 * Also, a parent who is session leader is able (before setsid() in the child)
195 * to inform the child when the controlling tty goes away (e.g. modem hangup).
197 static void sig_handler(int signal
)
200 kill(-child_pid
, signal
);
203 if (signal
== SIGTERM
)
204 kill(-child_pid
, SIGHUP
); /* because the shell often ignores SIGTERM */
208 * Let us delay all exit() calls when the user is not authenticated
209 * or the session not fully initialized (loginpam_session()).
211 static void __attribute__ ((__noreturn__
)) sleepexit(int eval
)
213 sleep((unsigned int)getlogindefs_num("FAIL_DELAY", LOGIN_EXIT_TIMEOUT
));
217 static const char *get_thishost(struct login_context
*cxt
, const char **domain
)
219 if (!cxt
->thishost
) {
220 cxt
->thishost
= xgethostname();
221 if (!cxt
->thishost
) {
226 cxt
->thisdomain
= strchr(cxt
->thishost
, '.');
228 *cxt
->thisdomain
++ = '\0';
232 *domain
= cxt
->thisdomain
;
233 return cxt
->thishost
;
237 * Output the /etc/motd file.
239 * It determines the name of a login announcement file and outputs it to the
240 * user's terminal at login time. The MOTD_FILE configuration option is a
241 * colon-delimited list of filenames. An empty MOTD_FILE option disables
242 * message-of-the-day printing completely.
244 static void motd(void)
246 char *motdlist
, *motdfile
;
249 mb
= getlogindefs_str("MOTD_FILE", _PATH_MOTDFILE
);
253 motdlist
= xstrdup(mb
);
255 for (motdfile
= strtok(motdlist
, ":"); motdfile
;
256 motdfile
= strtok(NULL
, ":")) {
261 fd
= open(motdfile
, O_RDONLY
, 0);
264 if (!fstat(fd
, &st
) && st
.st_size
)
265 sendfile(fileno(stdout
), fd
, NULL
, st
.st_size
);
273 * Nice and simple code provided by Linus Torvalds 16-Feb-93.
274 * Non-blocking stuff by Maciej W. Rozycki, macro@ds2.pg.gda.pl, 1999.
276 * He writes: "Login performs open() on a tty in a blocking mode.
277 * In some cases it may make login wait in open() for carrier infinitely,
278 * for example if the line is a simplistic case of a three-wire serial
279 * connection. I believe login should open the line in non-blocking mode,
280 * leaving the decision to make a connection to getty (where it actually
283 static void open_tty(const char *tty
)
287 fd
= open(tty
, O_RDWR
| O_NONBLOCK
);
289 syslog(LOG_ERR
, _("FATAL: can't reopen tty: %m"));
290 sleepexit(EXIT_FAILURE
);
295 syslog(LOG_ERR
, _("FATAL: %s is not a terminal"), tty
);
296 sleepexit(EXIT_FAILURE
);
299 flags
= fcntl(fd
, F_GETFL
);
300 flags
&= ~O_NONBLOCK
;
301 fcntl(fd
, F_SETFL
, flags
);
303 for (i
= 0; i
< fd
; i
++)
305 for (i
= 0; i
< 3; i
++)
312 #define chown_err(_what, _uid, _gid) \
313 syslog(LOG_ERR, _("chown (%s, %lu, %lu) failed: %m"), \
314 (_what), (unsigned long) (_uid), (unsigned long) (_gid))
316 #define chmod_err(_what, _mode) \
317 syslog(LOG_ERR, _("chmod (%s, %u) failed: %m"), (_what), (_mode))
319 static void chown_tty(struct login_context
*cxt
)
322 uid_t uid
= cxt
->pwd
->pw_uid
;
323 gid_t gid
= cxt
->pwd
->pw_gid
;
325 grname
= getlogindefs_str("TTYGROUP", TTYGRPNAME
);
326 if (grname
&& *grname
) {
327 struct group
*gr
= getgrnam(grname
);
328 if (gr
) /* group by name */
330 else /* group by ID */
331 gid
= (gid_t
) getlogindefs_num("TTYGROUP", gid
);
333 if (fchown(0, uid
, gid
)) /* tty */
334 chown_err(cxt
->tty_name
, uid
, gid
);
335 if (fchmod(0, cxt
->tty_mode
))
336 chmod_err(cxt
->tty_name
, cxt
->tty_mode
);
338 #ifdef LOGIN_CHOWN_VCS
339 if (is_consoletty(0)) {
340 if (chown(cxt
->vcsn
, uid
, gid
)) /* vcs */
341 chown_err(cxt
->vcsn
, uid
, gid
);
342 if (chmod(cxt
->vcsn
, cxt
->tty_mode
))
343 chmod_err(cxt
->vcsn
, cxt
->tty_mode
);
345 if (chown(cxt
->vcsan
, uid
, gid
)) /* vcsa */
346 chown_err(cxt
->vcsan
, uid
, gid
);
347 if (chmod(cxt
->vcsan
, cxt
->tty_mode
))
348 chmod_err(cxt
->vcsan
, cxt
->tty_mode
);
354 * Reads the current terminal path and initializes cxt->tty_* variables.
356 static void init_tty(struct login_context
*cxt
)
359 struct termios tt
, ttt
;
361 cxt
->tty_mode
= (mode_t
) getlogindefs_num("TTYPERM", TTY_MODE
);
363 get_terminal_name(&cxt
->tty_path
, &cxt
->tty_name
, &cxt
->tty_number
);
366 * In case login is suid it was possible to use a hardlink as stdin
367 * and exploit races for a local root exploit. (Wojciech Purczynski).
369 * More precisely, the problem is ttyn := ttyname(0); ...; chown(ttyn);
370 * here ttyname() might return "/tmp/x", a hardlink to a pseudotty.
371 * All of this is a problem only when login is suid, which it isn't.
373 if (!cxt
->tty_path
|| !*cxt
->tty_path
||
374 lstat(cxt
->tty_path
, &st
) != 0 || !S_ISCHR(st
.st_mode
) ||
375 (st
.st_nlink
> 1 && strncmp(cxt
->tty_path
, "/dev/", 5)) ||
376 access(cxt
->tty_path
, R_OK
| W_OK
) != 0) {
378 syslog(LOG_ERR
, _("FATAL: bad tty"));
379 sleepexit(EXIT_FAILURE
);
382 #ifdef LOGIN_CHOWN_VCS
383 if (cxt
->tty_number
) {
384 /* find names of Virtual Console devices, for later mode change */
385 snprintf(cxt
->vcsn
, sizeof(cxt
->vcsn
), "/dev/vcs%s", cxt
->tty_number
);
386 snprintf(cxt
->vcsan
, sizeof(cxt
->vcsan
), "/dev/vcsa%s", cxt
->tty_number
);
392 ttt
.c_cflag
&= ~HUPCL
;
394 if ((fchown(0, 0, 0) || fchmod(0, cxt
->tty_mode
)) && errno
!= EROFS
) {
396 syslog(LOG_ERR
, _("FATAL: %s: change permissions failed: %m"),
398 sleepexit(EXIT_FAILURE
);
401 /* Kill processes left on this tty */
402 tcsetattr(0, TCSANOW
, &ttt
);
405 * Let's close file descriptors before vhangup
406 * https://lkml.org/lkml/2012/6/5/145
409 close(STDOUT_FILENO
);
410 close(STDERR_FILENO
);
412 signal(SIGHUP
, SIG_IGN
); /* so vhangup() won't kill us */
414 signal(SIGHUP
, SIG_DFL
);
416 /* open stdin,stdout,stderr to the tty */
417 open_tty(cxt
->tty_path
);
419 /* restore tty modes */
420 tcsetattr(0, TCSAFLUSH
, &tt
);
425 * Logs failed login attempts in _PATH_BTMP, if it exists.
426 * Must be called only with username the name of an actual user.
427 * The most common login failure is to give password instead of username.
429 static void log_btmp(struct login_context
*cxt
)
434 memset(&ut
, 0, sizeof(ut
));
437 cxt
->username
? cxt
->username
: "(unknown)",
441 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
443 xstrncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
445 gettimeofday(&tv
, NULL
);
446 ut
.ut_tv
.tv_sec
= tv
.tv_sec
;
447 ut
.ut_tv
.tv_usec
= tv
.tv_usec
;
449 ut
.ut_type
= LOGIN_PROCESS
; /* XXX doesn't matter */
450 ut
.ut_pid
= cxt
->pid
;
453 xstrncpy(ut
.ut_host
, cxt
->hostname
, sizeof(ut
.ut_host
));
454 if (*cxt
->hostaddress
)
455 memcpy(&ut
.ut_addr_v6
, cxt
->hostaddress
,
456 sizeof(ut
.ut_addr_v6
));
459 updwtmpx(_PATH_BTMP
, &ut
);
464 static void log_audit(struct login_context
*cxt
, int status
)
467 struct passwd
*pwd
= cxt
->pwd
;
469 audit_fd
= audit_open();
472 if (!pwd
&& cxt
->username
)
473 pwd
= getpwnam(cxt
->username
);
475 audit_log_acct_message(audit_fd
,
479 cxt
->username
? cxt
->username
: "(unknown)",
480 pwd
? pwd
->pw_uid
: (unsigned int) -1,
488 #else /* !HAVE_LIBAUDIT */
489 # define log_audit(cxt, status)
490 #endif /* HAVE_LIBAUDIT */
492 static void log_lastlog(struct login_context
*cxt
)
494 struct sigaction sa
, oldsa_xfsz
;
502 /* lastlog is huge on systems with large UIDs, ignore SIGXFSZ */
503 memset(&sa
, 0, sizeof(sa
));
504 sa
.sa_handler
= SIG_IGN
;
505 sigaction(SIGXFSZ
, &sa
, &oldsa_xfsz
);
507 fd
= open(_PATH_LASTLOG
, O_RDWR
, 0);
511 if (lseek(fd
, (off_t
) cxt
->pwd
->pw_uid
* sizeof(ll
), SEEK_SET
) == -1)
515 * Print last log message.
518 if (read(fd
, (char *)&ll
, sizeof(ll
)) == sizeof(ll
) &&
520 time_t ll_time
= (time_t) ll
.ll_time
;
522 printf(_("Last login: %.*s "), 24 - 5, ctime(&ll_time
));
523 if (*ll
.ll_host
!= '\0')
524 printf(_("from %.*s\n"),
525 (int)sizeof(ll
.ll_host
), ll
.ll_host
);
527 printf(_("on %.*s\n"),
528 (int)sizeof(ll
.ll_line
), ll
.ll_line
);
530 if (lseek(fd
, (off_t
) cxt
->pwd
->pw_uid
* sizeof(ll
), SEEK_SET
) == -1)
534 memset((char *)&ll
, 0, sizeof(ll
));
537 ll
.ll_time
= t
; /* ll_time is always 32bit */
540 xstrncpy(ll
.ll_line
, cxt
->tty_name
, sizeof(ll
.ll_line
));
542 xstrncpy(ll
.ll_host
, cxt
->hostname
, sizeof(ll
.ll_host
));
544 if (write_all(fd
, (char *)&ll
, sizeof(ll
)))
545 warn(_("write lastlog failed"));
550 sigaction(SIGXFSZ
, &oldsa_xfsz
, NULL
); /* restore original setting */
554 * Update wtmp and utmp logs.
556 static void log_utmp(struct login_context
*cxt
)
562 utmpxname(_PATH_UTMP
);
567 * login sometimes overwrites the runlevel entry in /var/run/utmp,
568 * confusing sysvinit. I added a test for the entry type, and the
569 * problem was gone. (In a runlevel entry, st_pid is not really a pid
570 * but some number calculated from the previous and current runlevel.)
571 * -- Michael Riepe <michael@stud.uni-hannover.de>
573 while ((utp
= getutxent()))
574 if (utp
->ut_pid
== cxt
->pid
575 && utp
->ut_type
>= INIT_PROCESS
576 && utp
->ut_type
<= DEAD_PROCESS
)
579 /* If we can't find a pre-existing entry by pid, try by line.
580 * BSD network daemons may rely on this. */
581 if (utp
== NULL
&& cxt
->tty_name
) {
583 ut
.ut_type
= LOGIN_PROCESS
;
584 strncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
585 utp
= getutxline(&ut
);
588 /* If we can't find a pre-existing entry by pid and line, try it by id.
589 * Very stupid telnetd daemons don't set up utmp at all. (kzak) */
590 if (utp
== NULL
&& cxt
->tty_number
) {
592 ut
.ut_type
= DEAD_PROCESS
;
593 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
598 memcpy(&ut
, utp
, sizeof(ut
));
600 /* some gettys/telnetds don't initialize utmp... */
601 memset(&ut
, 0, sizeof(ut
));
603 if (cxt
->tty_number
&& ut
.ut_id
[0] == 0)
604 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
606 strncpy(ut
.ut_user
, cxt
->username
, sizeof(ut
.ut_user
));
608 xstrncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
610 gettimeofday(&tv
, NULL
);
611 ut
.ut_tv
.tv_sec
= tv
.tv_sec
;
612 ut
.ut_tv
.tv_usec
= tv
.tv_usec
;
613 ut
.ut_type
= USER_PROCESS
;
614 ut
.ut_pid
= cxt
->pid
;
616 xstrncpy(ut
.ut_host
, cxt
->hostname
, sizeof(ut
.ut_host
));
617 if (*cxt
->hostaddress
)
618 memcpy(&ut
.ut_addr_v6
, cxt
->hostaddress
,
619 sizeof(ut
.ut_addr_v6
));
625 updwtmpx(_PATH_WTMP
, &ut
);
628 static void log_syslog(struct login_context
*cxt
)
630 struct passwd
*pwd
= cxt
->pwd
;
635 if (!strncmp(cxt
->tty_name
, "ttyS", 4))
636 syslog(LOG_INFO
, _("DIALUP AT %s BY %s"),
637 cxt
->tty_name
, pwd
->pw_name
);
641 syslog(LOG_NOTICE
, _("ROOT LOGIN ON %s FROM %s"),
642 cxt
->tty_name
, cxt
->hostname
);
644 syslog(LOG_NOTICE
, _("ROOT LOGIN ON %s"), cxt
->tty_name
);
647 syslog(LOG_INFO
, _("LOGIN ON %s BY %s FROM %s"),
648 cxt
->tty_name
, pwd
->pw_name
, cxt
->hostname
);
650 syslog(LOG_INFO
, _("LOGIN ON %s BY %s"), cxt
->tty_name
,
655 static struct passwd
*get_passwd_entry(const char *username
,
659 struct passwd
*res
= NULL
;
662 if (!pwdbuf
|| !username
)
665 *pwdbuf
= xrealloc(*pwdbuf
, UL_GETPW_BUFSIZ
);
667 x
= getpwnam_r(username
, pwd
, *pwdbuf
, UL_GETPW_BUFSIZ
, &res
);
675 /* encapsulate stupid "void **" pam_get_item() API */
676 static int loginpam_get_username(pam_handle_t
*pamh
, char **name
)
678 const void *item
= (void *)*name
;
680 rc
= pam_get_item(pamh
, PAM_USER
, &item
);
681 *name
= (char *)item
;
685 static void loginpam_err(pam_handle_t
*pamh
, int retcode
)
687 const char *msg
= pam_strerror(pamh
, retcode
);
690 fprintf(stderr
, "\n%s\n", msg
);
691 syslog(LOG_ERR
, "%s", msg
);
693 pam_end(pamh
, retcode
);
694 sleepexit(EXIT_FAILURE
);
698 * Composes "<host> login: " string; or returns "login: " if -H is given.
700 static const char *loginpam_get_prompt(struct login_context
*cxt
)
703 char *prompt
, *dflt_prompt
= _("login: ");
706 if (cxt
->nohost
|| !(host
= get_thishost(cxt
, NULL
)))
709 sz
= strlen(host
) + 1 + strlen(dflt_prompt
) + 1;
711 prompt
= xmalloc(sz
);
712 snprintf(prompt
, sz
, "%s %s", host
, dflt_prompt
);
717 static pam_handle_t
*init_loginpam(struct login_context
*cxt
)
719 pam_handle_t
*pamh
= NULL
;
723 * username is initialized to NULL and if specified on the command line
724 * it is set. Therefore, we are safe not setting it to anything.
726 rc
= pam_start(cxt
->remote
? "remote" : "login",
727 cxt
->username
, &cxt
->conv
, &pamh
);
728 if (rc
!= PAM_SUCCESS
) {
729 warnx(_("PAM failure, aborting: %s"), pam_strerror(pamh
, rc
));
730 syslog(LOG_ERR
, _("Couldn't initialize PAM: %s"),
731 pam_strerror(pamh
, rc
));
732 sleepexit(EXIT_FAILURE
);
735 /* hostname & tty are either set to NULL or their correct values,
736 * depending on how much we know. */
737 rc
= pam_set_item(pamh
, PAM_RHOST
, cxt
->hostname
);
738 if (is_pam_failure(rc
))
739 loginpam_err(pamh
, rc
);
741 rc
= pam_set_item(pamh
, PAM_TTY
, cxt
->tty_name
);
742 if (is_pam_failure(rc
))
743 loginpam_err(pamh
, rc
);
746 * Andrew.Taylor@cal.montage.ca: Provide a user prompt to PAM so that
747 * the "login: " prompt gets localized. Unfortunately, PAM doesn't have
748 * an interface to specify the "Password: " string (yet).
750 rc
= pam_set_item(pamh
, PAM_USER_PROMPT
, loginpam_get_prompt(cxt
));
751 if (is_pam_failure(rc
))
752 loginpam_err(pamh
, rc
);
754 /* We don't need the original username. We have to follow PAM. */
756 cxt
->username
= NULL
;
762 static void loginpam_auth(struct login_context
*cxt
)
764 int rc
, show_unknown
;
765 unsigned int retries
, failcount
= 0;
766 const char *hostname
= cxt
->hostname
? cxt
->hostname
:
767 cxt
->tty_name
? cxt
->tty_name
: "<unknown>";
768 pam_handle_t
*pamh
= cxt
->pamh
;
770 /* if we didn't get a user on the command line, set it to NULL */
771 loginpam_get_username(pamh
, &cxt
->username
);
773 show_unknown
= getlogindefs_bool("LOG_UNKFAIL_ENAB", 0);
774 retries
= getlogindefs_num("LOGIN_RETRIES", LOGIN_MAX_TRIES
);
777 * There may be better ways to deal with some of these conditions, but
778 * at least this way I don't think we'll be giving away information...
780 * Perhaps someday we can trust that all PAM modules will pay attention
781 * to failure count and get rid of LOGIN_MAX_TRIES?
783 rc
= pam_authenticate(pamh
, 0);
785 while ((++failcount
< retries
) &&
786 ((rc
== PAM_AUTH_ERR
) ||
787 (rc
== PAM_USER_UNKNOWN
) ||
788 (rc
== PAM_CRED_INSUFFICIENT
) ||
789 (rc
== PAM_AUTHINFO_UNAVAIL
))) {
791 if (rc
== PAM_USER_UNKNOWN
&& !show_unknown
)
793 * Logging unknown usernames may be a security issue if
794 * a user enters her password instead of her login name.
796 cxt
->username
= NULL
;
798 loginpam_get_username(pamh
, &cxt
->username
);
801 _("FAILED LOGIN %u FROM %s FOR %s, %s"),
803 cxt
->username
? cxt
->username
: "(unknown)",
804 pam_strerror(pamh
, rc
));
809 fprintf(stderr
, _("Login incorrect\n\n"));
811 pam_set_item(pamh
, PAM_USER
, NULL
);
812 rc
= pam_authenticate(pamh
, 0);
815 if (is_pam_failure(rc
)) {
817 if (rc
== PAM_USER_UNKNOWN
&& !show_unknown
)
818 cxt
->username
= NULL
;
820 loginpam_get_username(pamh
, &cxt
->username
);
822 if (rc
== PAM_MAXTRIES
)
824 _("TOO MANY LOGIN TRIES (%u) FROM %s FOR %s, %s"),
826 cxt
->username
? cxt
->username
: "(unknown)",
827 pam_strerror(pamh
, rc
));
830 _("FAILED LOGIN SESSION FROM %s FOR %s, %s"),
832 cxt
->username
? cxt
->username
: "(unknown)",
833 pam_strerror(pamh
, rc
));
838 fprintf(stderr
, _("\nLogin incorrect\n"));
840 sleepexit(EXIT_SUCCESS
);
844 static void loginpam_acct(struct login_context
*cxt
)
847 pam_handle_t
*pamh
= cxt
->pamh
;
849 rc
= pam_acct_mgmt(pamh
, 0);
851 if (rc
== PAM_NEW_AUTHTOK_REQD
)
852 rc
= pam_chauthtok(pamh
, PAM_CHANGE_EXPIRED_AUTHTOK
);
854 if (is_pam_failure(rc
))
855 loginpam_err(pamh
, rc
);
858 * Grab the user information out of the password file for future use.
859 * First get the username that we are actually using, though.
861 rc
= loginpam_get_username(pamh
, &cxt
->username
);
862 if (is_pam_failure(rc
))
863 loginpam_err(pamh
, rc
);
865 if (!cxt
->username
|| !*cxt
->username
) {
866 warnx(_("\nSession setup problem, abort."));
867 syslog(LOG_ERR
, _("NULL user name in %s:%d. Abort."),
868 __FUNCTION__
, __LINE__
);
869 pam_end(pamh
, PAM_SYSTEM_ERR
);
870 sleepexit(EXIT_FAILURE
);
875 * Note that the position of the pam_setcred() call is discussable:
877 * - the PAM docs recommend pam_setcred() before pam_open_session()
878 * - but the original RFC http://www.opengroup.org/rfc/mirror-rfc/rfc86.0.txt
879 * uses pam_setcred() after pam_open_session()
881 * The old login versions (before year 2011) followed the RFC. This is probably
882 * not optimal, because there could be a dependence between some session modules
883 * and the user's credentials.
885 * The best is probably to follow openssh and call pam_setcred() before and
886 * after pam_open_session(). -- kzak@redhat.com (18-Nov-2011)
889 static void loginpam_session(struct login_context
*cxt
)
892 pam_handle_t
*pamh
= cxt
->pamh
;
894 rc
= pam_setcred(pamh
, PAM_ESTABLISH_CRED
);
895 if (is_pam_failure(rc
))
896 loginpam_err(pamh
, rc
);
898 rc
= pam_open_session(pamh
, 0);
899 if (is_pam_failure(rc
)) {
900 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
901 loginpam_err(pamh
, rc
);
904 rc
= pam_setcred(pamh
, PAM_REINITIALIZE_CRED
);
905 if (is_pam_failure(rc
)) {
906 pam_close_session(pamh
, 0);
907 loginpam_err(pamh
, rc
);
912 * Detach the controlling terminal, fork, restore syslog stuff, and create
915 static void fork_session(struct login_context
*cxt
)
917 struct sigaction sa
, oldsa_hup
, oldsa_term
;
919 signal(SIGALRM
, SIG_DFL
);
920 signal(SIGQUIT
, SIG_DFL
);
921 signal(SIGTSTP
, SIG_IGN
);
923 memset(&sa
, 0, sizeof(sa
));
924 sa
.sa_handler
= SIG_IGN
;
925 sigaction(SIGINT
, &sa
, NULL
);
927 sigaction(SIGHUP
, &sa
, &oldsa_hup
); /* ignore when TIOCNOTTY */
930 * Detach the controlling tty.
931 * We don't need the tty in a parent who only waits for a child.
932 * The child calls setsid() that detaches from the tty as well.
934 ioctl(0, TIOCNOTTY
, NULL
);
937 * We have to beware of SIGTERM, because leaving a PAM session
938 * without pam_close_session() is a pretty bad thing.
940 sa
.sa_handler
= sig_handler
;
941 sigaction(SIGHUP
, &sa
, NULL
);
942 sigaction(SIGTERM
, &sa
, &oldsa_term
);
947 * We must fork before setuid(), because we need to call
948 * pam_close_session() as root.
952 warn(_("fork failed"));
954 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
955 pam_end(cxt
->pamh
, pam_close_session(cxt
->pamh
, 0));
956 sleepexit(EXIT_FAILURE
);
961 * parent - wait for child to finish, then clean up session
966 sa
.sa_handler
= SIG_IGN
;
967 sigaction(SIGQUIT
, &sa
, NULL
);
968 sigaction(SIGINT
, &sa
, NULL
);
970 /* wait as long as any child is there */
971 while (wait(NULL
) == -1 && errno
== EINTR
) ;
972 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
);
974 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
975 pam_end(cxt
->pamh
, pam_close_session(cxt
->pamh
, 0));
982 sigaction(SIGHUP
, &oldsa_hup
, NULL
); /* restore old state */
983 sigaction(SIGTERM
, &oldsa_term
, NULL
);
988 * Problem: if the user's shell is a shell like ash that doesn't do
989 * setsid() or setpgrp(), then a ctrl-\, sending SIGQUIT to every
990 * process in the pgrp, will kill us.
993 /* start new session */
996 /* make sure we have a controlling tty */
997 open_tty(cxt
->tty_path
);
998 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
); /* reopen */
1001 * TIOCSCTTY: steal tty from other process group.
1003 if (ioctl(0, TIOCSCTTY
, 1))
1004 syslog(LOG_ERR
, _("TIOCSCTTY failed: %m"));
1005 signal(SIGINT
, SIG_DFL
);
1009 * Initialize $TERM, $HOME, ...
1011 static void init_environ(struct login_context
*cxt
)
1013 struct passwd
*pwd
= cxt
->pwd
;
1014 char *termenv
, **env
;
1018 termenv
= getenv("TERM");
1020 termenv
= xstrdup(termenv
);
1022 /* destroy environment unless user has requested preservation (-p) */
1023 if (!cxt
->keep_env
) {
1024 environ
= xmalloc(sizeof(char *));
1025 memset(environ
, 0, sizeof(char *));
1028 xsetenv("HOME", pwd
->pw_dir
, 0); /* legal to override */
1029 xsetenv("USER", pwd
->pw_name
, 1);
1030 xsetenv("SHELL", pwd
->pw_shell
, 1);
1031 xsetenv("TERM", termenv
? termenv
: "dumb", 1);
1035 if (logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH
) != 0)
1036 err(EXIT_FAILURE
, _("failed to set the %s environment variable"), "PATH");
1038 } else if (logindefs_setenv("PATH", "ENV_ROOTPATH", NULL
) != 0 &&
1039 logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT
) != 0) {
1040 err(EXIT_FAILURE
, _("failed to set the %s environment variable"), "PATH");
1043 /* mailx will give a funny error msg if you forget this one */
1044 len
= snprintf(tmp
, sizeof(tmp
), "%s/%s", _PATH_MAILDIR
, pwd
->pw_name
);
1045 if (len
> 0 && (size_t) len
< sizeof(tmp
))
1046 xsetenv("MAIL", tmp
, 0);
1048 /* LOGNAME is not documented in login(1) but HP-UX 6.5 does it. We'll
1049 * not allow modifying it.
1051 xsetenv("LOGNAME", pwd
->pw_name
, 1);
1053 env
= pam_getenvlist(cxt
->pamh
);
1054 for (i
= 0; env
&& env
[i
]; i
++)
1059 * This is called for the -h option, initializes cxt->{hostname,hostaddress}.
1061 static void init_remote_info(struct login_context
*cxt
, char *remotehost
)
1065 struct addrinfo hints
, *info
= NULL
;
1069 get_thishost(cxt
, &domain
);
1071 if (domain
&& (p
= strchr(remotehost
, '.')) &&
1072 strcasecmp(p
+ 1, domain
) == 0)
1075 cxt
->hostname
= xstrdup(remotehost
);
1077 memset(&hints
, 0, sizeof(hints
));
1078 hints
.ai_flags
= AI_ADDRCONFIG
;
1079 cxt
->hostaddress
[0] = 0;
1081 if (getaddrinfo(cxt
->hostname
, NULL
, &hints
, &info
) == 0 && info
) {
1082 if (info
->ai_family
== AF_INET
) {
1083 struct sockaddr_in
*sa
=
1084 (struct sockaddr_in
*) info
->ai_addr
;
1086 memcpy(cxt
->hostaddress
, &(sa
->sin_addr
), sizeof(sa
->sin_addr
));
1088 } else if (info
->ai_family
== AF_INET6
) {
1089 struct sockaddr_in6
*sa
=
1090 (struct sockaddr_in6
*) info
->ai_addr
;
1092 memcpy(cxt
->hostaddress
, &(sa
->sin6_addr
), sizeof(sa
->sin6_addr
));
1098 static void __attribute__((__noreturn__
)) usage(void)
1100 fputs(USAGE_HEADER
, stdout
);
1101 printf(_(" %s [-p] [-h <host>] [-H] [[-f] <username>]\n"), program_invocation_short_name
);
1102 fputs(USAGE_SEPARATOR
, stdout
);
1103 fputs(_("Begin a session on the system.\n"), stdout
);
1105 fputs(USAGE_OPTIONS
, stdout
);
1106 puts(_(" -p do not destroy the environment"));
1107 puts(_(" -f skip a second login authentication"));
1108 puts(_(" -h <host> hostname to be used for utmp logging"));
1109 puts(_(" -H suppress hostname in the login prompt"));
1110 printf(" --help %s\n", USAGE_OPTSTR_HELP
);
1111 printf(" -V, --version %s\n", USAGE_OPTSTR_VERSION
);
1112 printf(USAGE_MAN_TAIL("login(1)"));
1116 int main(int argc
, char **argv
)
1120 char *childArgv
[10];
1124 struct sigaction act
;
1126 char *pwdbuf
= NULL
;
1127 struct passwd
*pwd
= NULL
, _pwd
;
1129 struct login_context cxt
= {
1130 .tty_mode
= TTY_MODE
, /* tty chmod() */
1131 .pid
= getpid(), /* PID */
1132 #ifdef HAVE_SECURITY_PAM_MISC_H
1133 .conv
= { misc_conv
, NULL
} /* Linux-PAM conversation function */
1134 #elif defined(HAVE_SECURITY_OPENPAM_H)
1135 .conv
= { openpam_ttyconv
, NULL
} /* OpenPAM conversation function */
1140 /* the only two longopts to satisfy UL standards */
1141 enum { HELP_OPTION
= CHAR_MAX
+ 1 };
1142 static const struct option longopts
[] = {
1143 {"help", no_argument
, NULL
, HELP_OPTION
},
1144 {"version", no_argument
, NULL
, 'V'},
1148 timeout
= (unsigned int)getlogindefs_num("LOGIN_TIMEOUT", LOGIN_TIMEOUT
);
1150 signal(SIGALRM
, timedout
);
1151 (void) sigaction(SIGALRM
, NULL
, &act
);
1152 act
.sa_flags
&= ~SA_RESTART
;
1153 sigaction(SIGALRM
, &act
, NULL
);
1155 signal(SIGQUIT
, SIG_IGN
);
1156 signal(SIGINT
, SIG_IGN
);
1158 setlocale(LC_ALL
, "");
1159 bindtextdomain(PACKAGE
, LOCALEDIR
);
1160 textdomain(PACKAGE
);
1162 setpriority(PRIO_PROCESS
, 0, 0);
1163 initproctitle(argc
, argv
);
1166 * -p is used by getty to tell login not to destroy the environment
1167 * -f is used to skip a second login authentication
1168 * -h is used by other servers to pass the name of the remote
1169 * host to login so that it may be placed in utmp and wtmp
1171 while ((c
= getopt_long(argc
, argv
, "fHh:pV", longopts
, NULL
)) != -1)
1184 _("login: -h is for superuser only\n"));
1187 init_remote_info(&cxt
, optarg
);
1195 printf(UTIL_LINUX_VERSION
);
1196 return EXIT_SUCCESS
;
1200 errtryhelp(EXIT_FAILURE
);
1207 cxt
.username
= xstrdup(p
);
1209 /* Wipe the name - some people mistype their password here. */
1210 /* (Of course we are too late, but perhaps this helps a little...) */
1215 for (cnt
= get_fd_tabsize() - 1; cnt
> 2; cnt
--)
1218 setpgrp(); /* set pgid to pid this means that setsid() will fail */
1221 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
);
1223 init_loginpam(&cxt
);
1225 /* login -f, then the user has already been authenticated */
1226 cxt
.noauth
= cxt
.noauth
&& getuid() == 0 ? 1 : 0;
1229 loginpam_auth(&cxt
);
1232 * Authentication may be skipped (for example, during krlogin, rlogin,
1233 * etc...), but it doesn't mean that we can skip other account checks.
1234 * The account could be disabled or the password has expired (although
1235 * the kerberos ticket is valid). -- kzak@redhat.com (22-Feb-2006)
1237 loginpam_acct(&cxt
);
1239 if (!(cxt
.pwd
= get_passwd_entry(cxt
.username
, &pwdbuf
, &_pwd
))) {
1240 warnx(_("\nSession setup problem, abort."));
1241 syslog(LOG_ERR
, _("Invalid user name \"%s\" in %s:%d. Abort."),
1242 cxt
.username
, __FUNCTION__
, __LINE__
);
1243 pam_end(cxt
.pamh
, PAM_SYSTEM_ERR
);
1244 sleepexit(EXIT_FAILURE
);
1248 cxt
.username
= pwd
->pw_name
;
1251 * Initialize the supplementary group list. This should be done before
1252 * pam_setcred, because PAM modules might add groups during that call.
1254 * For root we don't call initgroups, instead we call setgroups with
1255 * group 0. This avoids the need to step through the whole group file,
1256 * which can cause problems if NIS, NIS+, LDAP or something similar
1257 * is used and the machine has network problems.
1259 retcode
= pwd
->pw_uid
? initgroups(cxt
.username
, pwd
->pw_gid
) : /* user */
1260 setgroups(0, NULL
); /* root */
1262 syslog(LOG_ERR
, _("groups initialization failed: %m"));
1263 warnx(_("\nSession setup problem, abort."));
1264 pam_end(cxt
.pamh
, PAM_SYSTEM_ERR
);
1265 sleepexit(EXIT_FAILURE
);
1269 * Open PAM session (after successful authentication and account check).
1271 loginpam_session(&cxt
);
1273 /* committed to login -- turn off timeout */
1274 alarm((unsigned int)0);
1278 cxt
.quiet
= get_hushlogin_status(pwd
, 1);
1286 if (setgid(pwd
->pw_gid
) < 0 && pwd
->pw_gid
) {
1287 syslog(LOG_ALERT
, _("setgid() failed"));
1291 if (pwd
->pw_shell
== NULL
|| *pwd
->pw_shell
== '\0')
1292 pwd
->pw_shell
= _PATH_BSHELL
;
1294 init_environ(&cxt
); /* init $HOME, $TERM ... */
1296 setproctitle("login", cxt
.username
);
1303 #ifdef LOGIN_STAT_MAIL
1305 * This turns out to be a bad idea: when the mail spool
1306 * is NFS mounted, and the NFS connection hangs, the
1307 * login hangs, even root cannot login.
1308 * Checking for mail should be done from the shell.
1314 mail
= getenv("MAIL");
1315 if (mail
&& stat(mail
, &st
) == 0 && st
.st_size
!= 0) {
1316 if (st
.st_mtime
> st
.st_atime
)
1317 printf(_("You have new mail.\n"));
1319 printf(_("You have mail.\n"));
1326 * Detach the controlling terminal, fork, and create a new session
1327 * and reinitialize syslog stuff.
1331 /* discard permissions last so we can't get killed and drop core */
1332 if (setuid(pwd
->pw_uid
) < 0 && pwd
->pw_uid
) {
1333 syslog(LOG_ALERT
, _("setuid() failed"));
1337 /* wait until here to change directory! */
1338 if (chdir(pwd
->pw_dir
) < 0) {
1339 warn(_("%s: change directory failed"), pwd
->pw_dir
);
1341 if (!getlogindefs_bool("DEFAULT_HOME", 1))
1346 printf(_("Logging in with home = \"/\".\n"));
1349 /* if the shell field has a space: treat it like a shell script */
1350 if (strchr(pwd
->pw_shell
, ' ')) {
1351 buff
= xmalloc(strlen(pwd
->pw_shell
) + 6);
1353 strcpy(buff
, "exec ");
1354 strcat(buff
, pwd
->pw_shell
);
1355 childArgv
[childArgc
++] = "/bin/sh";
1356 childArgv
[childArgc
++] = "-sh";
1357 childArgv
[childArgc
++] = "-c";
1358 childArgv
[childArgc
++] = buff
;
1360 char tbuf
[PATH_MAX
+ 2], *p
;
1363 xstrncpy(tbuf
+ 1, ((p
= strrchr(pwd
->pw_shell
, '/')) ?
1364 p
+ 1 : pwd
->pw_shell
), sizeof(tbuf
) - 1);
1366 childArgv
[childArgc
++] = pwd
->pw_shell
;
1367 childArgv
[childArgc
++] = xstrdup(tbuf
);
1370 childArgv
[childArgc
++] = NULL
;
1372 execvp(childArgv
[0], childArgv
+ 1);
1374 if (!strcmp(childArgv
[0], "/bin/sh"))
1375 warn(_("couldn't exec shell script"));
1377 warn(_("no shell"));