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>
50 #include <sys/syslog.h>
51 #include <sys/sysmacros.h>
52 #ifdef HAVE_LINUX_MAJOR_H
53 # include <linux/major.h>
57 #include <security/pam_appl.h>
58 #include <security/pam_misc.h>
59 #include <sys/sendfile.h>
62 # include <libaudit.h>
66 #include "setproctitle.h"
67 #include "pathnames.h"
72 #include "fileutils.h"
75 #include "logindefs.h"
77 #define is_pam_failure(_rc) ((_rc) != PAM_SUCCESS)
79 #define LOGIN_MAX_TRIES 3
80 #define LOGIN_EXIT_TIMEOUT 5
81 #define LOGIN_TIMEOUT 60
84 # define TTY_MODE 0620
86 # define TTY_MODE 0600
89 #define TTYGRPNAME "tty" /* name of group to own ttys */
90 #define VCS_PATH_MAX 64
93 * Login control struct
95 struct login_context
{
96 const char *tty_path
; /* ttyname() return value */
97 const char *tty_name
; /* tty_path without /dev prefix */
98 const char *tty_number
; /* end of the tty_path */
99 mode_t tty_mode
; /* chmod() mode */
101 char *username
; /* from command line or PAM */
103 struct passwd
*pwd
; /* user info */
105 pam_handle_t
*pamh
; /* PAM handler */
106 struct pam_conv conv
; /* PAM conversation */
108 #ifdef LOGIN_CHOWN_VCS
109 char vcsn
[VCS_PATH_MAX
]; /* virtual console name */
110 char vcsan
[VCS_PATH_MAX
];
113 char *thishost
; /* this machine */
114 char *thisdomain
; /* this machine's domain */
115 char *hostname
; /* remote machine */
116 char hostaddress
[16]; /* remote address */
119 int quiet
; /* 1 if hush file exists */
121 unsigned int remote
:1, /* login -h */
122 nohost
:1, /* login -H */
123 noauth
:1, /* login -f */
124 keep_env
:1; /* login -p */
128 * This bounds the time given to login. Not a define, so it can
129 * be patched on machines where it's too small.
131 static unsigned int timeout
= LOGIN_TIMEOUT
;
132 static int child_pid
= 0;
133 static volatile int got_sig
= 0;
135 #ifdef LOGIN_CHOWN_VCS
136 /* true if the filedescriptor fd is a console tty, very Linux specific */
137 static int is_consoletty(int fd
)
141 if ((fstat(fd
, &stb
) >= 0)
142 && (major(stb
.st_rdev
) == TTY_MAJOR
)
143 && (minor(stb
.st_rdev
) < 64)) {
152 * Robert Ambrose writes:
153 * A couple of my users have a problem with login processes hanging around
154 * soaking up pts's. What they seem to hung up on is trying to write out the
155 * message 'Login timed out after %d seconds' when the connection has already
157 * What I did was add a second timeout while trying to write the message, so
158 * the process just exits if the second timeout expires.
160 static void __attribute__ ((__noreturn__
))
161 timedout2(int sig
__attribute__ ((__unused__
)))
168 tcsetattr(0, TCSANOW
, &ti
);
169 exit(EXIT_SUCCESS
); /* %% */
172 static void timedout(int sig
__attribute__ ((__unused__
)))
174 signal(SIGALRM
, timedout2
);
176 /* TRANSLATORS: The standard value for %u is 60. */
177 warnx(_("timed out after %u seconds"), timeout
);
178 signal(SIGALRM
, SIG_IGN
);
184 * This handler allows to inform a shell about signals to login. If you have
185 * (root) permissions, you can kill all login children by one signal to the
188 * Also, a parent who is session leader is able (before setsid() in the child)
189 * to inform the child when the controlling tty goes away (e.g. modem hangup).
191 static void sig_handler(int signal
)
194 kill(-child_pid
, signal
);
197 if (signal
== SIGTERM
)
198 kill(-child_pid
, SIGHUP
); /* because the shell often ignores SIGTERM */
202 * Let us delay all exit() calls when the user is not authenticated
203 * or the session not fully initialized (loginpam_session()).
205 static void __attribute__ ((__noreturn__
)) sleepexit(int eval
)
207 sleep((unsigned int)getlogindefs_num("FAIL_DELAY", LOGIN_EXIT_TIMEOUT
));
211 static const char *get_thishost(struct login_context
*cxt
, const char **domain
)
213 if (!cxt
->thishost
) {
214 cxt
->thishost
= xgethostname();
215 if (!cxt
->thishost
) {
220 cxt
->thisdomain
= strchr(cxt
->thishost
, '.');
222 *cxt
->thisdomain
++ = '\0';
226 *domain
= cxt
->thisdomain
;
227 return cxt
->thishost
;
231 * Output the /etc/motd file.
233 * It determines the name of a login announcement file and outputs it to the
234 * user's terminal at login time. The MOTD_FILE configuration option is a
235 * colon-delimited list of filenames. An empty MOTD_FILE option disables
236 * message-of-the-day printing completely.
238 static void motd(void)
240 char *motdlist
, *motdfile
;
243 mb
= getlogindefs_str("MOTD_FILE", _PATH_MOTDFILE
);
247 motdlist
= xstrdup(mb
);
249 for (motdfile
= strtok(motdlist
, ":"); motdfile
;
250 motdfile
= strtok(NULL
, ":")) {
255 if (stat(motdfile
, &st
) || !st
.st_size
)
257 fd
= open(motdfile
, O_RDONLY
, 0);
261 sendfile(fileno(stdout
), fd
, NULL
, st
.st_size
);
269 * Nice and simple code provided by Linus Torvalds 16-Feb-93.
270 * Non-blocking stuff by Maciej W. Rozycki, macro@ds2.pg.gda.pl, 1999.
272 * He writes: "Login performs open() on a tty in a blocking mode.
273 * In some cases it may make login wait in open() for carrier infinitely,
274 * for example if the line is a simplistic case of a three-wire serial
275 * connection. I believe login should open the line in non-blocking mode,
276 * leaving the decision to make a connection to getty (where it actually
279 static void open_tty(const char *tty
)
283 fd
= open(tty
, O_RDWR
| O_NONBLOCK
);
285 syslog(LOG_ERR
, _("FATAL: can't reopen tty: %m"));
286 sleepexit(EXIT_FAILURE
);
291 syslog(LOG_ERR
, _("FATAL: %s is not a terminal"), tty
);
292 sleepexit(EXIT_FAILURE
);
295 flags
= fcntl(fd
, F_GETFL
);
296 flags
&= ~O_NONBLOCK
;
297 fcntl(fd
, F_SETFL
, flags
);
299 for (i
= 0; i
< fd
; i
++)
301 for (i
= 0; i
< 3; i
++)
308 #define chown_err(_what, _uid, _gid) \
309 syslog(LOG_ERR, _("chown (%s, %lu, %lu) failed: %m"), \
310 (_what), (unsigned long) (_uid), (unsigned long) (_gid))
312 #define chmod_err(_what, _mode) \
313 syslog(LOG_ERR, _("chmod (%s, %u) failed: %m"), (_what), (_mode))
315 static void chown_tty(struct login_context
*cxt
)
318 uid_t uid
= cxt
->pwd
->pw_uid
;
319 gid_t gid
= cxt
->pwd
->pw_gid
;
321 grname
= getlogindefs_str("TTYGROUP", TTYGRPNAME
);
322 if (grname
&& *grname
) {
323 struct group
*gr
= getgrnam(grname
);
324 if (gr
) /* group by name */
326 else /* group by ID */
327 gid
= (gid_t
) getlogindefs_num("TTYGROUP", gid
);
329 if (fchown(0, uid
, gid
)) /* tty */
330 chown_err(cxt
->tty_name
, uid
, gid
);
331 if (fchmod(0, cxt
->tty_mode
))
332 chmod_err(cxt
->tty_name
, cxt
->tty_mode
);
334 #ifdef LOGIN_CHOWN_VCS
335 if (is_consoletty(0)) {
336 if (chown(cxt
->vcsn
, uid
, gid
)) /* vcs */
337 chown_err(cxt
->vcsn
, uid
, gid
);
338 if (chmod(cxt
->vcsn
, cxt
->tty_mode
))
339 chmod_err(cxt
->vcsn
, cxt
->tty_mode
);
341 if (chown(cxt
->vcsan
, uid
, gid
)) /* vcsa */
342 chown_err(cxt
->vcsan
, uid
, gid
);
343 if (chmod(cxt
->vcsan
, cxt
->tty_mode
))
344 chmod_err(cxt
->vcsan
, cxt
->tty_mode
);
350 * Reads the currect terminal path and initializes cxt->tty_* variables.
352 static void init_tty(struct login_context
*cxt
)
355 struct termios tt
, ttt
;
357 cxt
->tty_mode
= (mode_t
) getlogindefs_num("TTYPERM", TTY_MODE
);
359 get_terminal_name(0, &cxt
->tty_path
, &cxt
->tty_name
, &cxt
->tty_number
);
362 * In case login is suid it was possible to use a hardlink as stdin
363 * and exploit races for a local root exploit. (Wojciech Purczynski).
365 * More precisely, the problem is ttyn := ttyname(0); ...; chown(ttyn);
366 * here ttyname() might return "/tmp/x", a hardlink to a pseudotty.
367 * All of this is a problem only when login is suid, which it isn't.
369 if (!cxt
->tty_path
|| !*cxt
->tty_path
||
370 lstat(cxt
->tty_path
, &st
) != 0 || !S_ISCHR(st
.st_mode
) ||
371 (st
.st_nlink
> 1 && strncmp(cxt
->tty_path
, "/dev/", 5)) ||
372 access(cxt
->tty_path
, R_OK
| W_OK
) != 0) {
374 syslog(LOG_ERR
, _("FATAL: bad tty"));
375 sleepexit(EXIT_FAILURE
);
378 #ifdef LOGIN_CHOWN_VCS
379 if (cxt
->tty_number
) {
380 /* find names of Virtual Console devices, for later mode change */
381 snprintf(cxt
->vcsn
, sizeof(cxt
->vcsn
), "/dev/vcs%s", cxt
->tty_number
);
382 snprintf(cxt
->vcsan
, sizeof(cxt
->vcsan
), "/dev/vcsa%s", cxt
->tty_number
);
388 ttt
.c_cflag
&= ~HUPCL
;
390 if ((fchown(0, 0, 0) || fchmod(0, cxt
->tty_mode
)) && errno
!= EROFS
) {
392 syslog(LOG_ERR
, _("FATAL: %s: change permissions failed: %m"),
394 sleepexit(EXIT_FAILURE
);
397 /* Kill processes left on this tty */
398 tcsetattr(0, TCSANOW
, &ttt
);
401 * Let's close file decriptors before vhangup
402 * https://lkml.org/lkml/2012/6/5/145
405 close(STDOUT_FILENO
);
406 close(STDERR_FILENO
);
408 signal(SIGHUP
, SIG_IGN
); /* so vhangup() wont kill us */
410 signal(SIGHUP
, SIG_DFL
);
412 /* open stdin,stdout,stderr to the tty */
413 open_tty(cxt
->tty_path
);
415 /* restore tty modes */
416 tcsetattr(0, TCSAFLUSH
, &tt
);
421 * Logs failed login attempts in _PATH_BTMP, if it exists.
422 * Must be called only with username the name of an actual user.
423 * The most common login failure is to give password instead of username.
425 static void log_btmp(struct login_context
*cxt
)
430 memset(&ut
, 0, sizeof(ut
));
433 cxt
->username
? cxt
->username
: "(unknown)",
437 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
439 xstrncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
441 #if defined(_HAVE_UT_TV) /* in <utmpbits.h> included by <utmp.h> */
442 gettimeofday(&tv
, NULL
);
443 ut
.ut_tv
.tv_sec
= tv
.tv_sec
;
444 ut
.ut_tv
.tv_usec
= tv
.tv_usec
;
449 ut
.ut_time
= t
; /* ut_time is not always a time_t */
453 ut
.ut_type
= LOGIN_PROCESS
; /* XXX doesn't matter */
454 ut
.ut_pid
= cxt
->pid
;
457 xstrncpy(ut
.ut_host
, cxt
->hostname
, sizeof(ut
.ut_host
));
458 if (*cxt
->hostaddress
)
459 memcpy(&ut
.ut_addr_v6
, cxt
->hostaddress
,
460 sizeof(ut
.ut_addr_v6
));
463 updwtmp(_PATH_BTMP
, &ut
);
468 static void log_audit(struct login_context
*cxt
, int status
)
471 struct passwd
*pwd
= cxt
->pwd
;
473 audit_fd
= audit_open();
476 if (!pwd
&& cxt
->username
)
477 pwd
= getpwnam(cxt
->username
);
479 audit_log_acct_message(audit_fd
,
483 cxt
->username
? cxt
->username
: "(unknown)",
484 pwd
? pwd
->pw_uid
: (unsigned int) -1,
492 #else /* !HAVE_LIBAUDIT */
493 # define log_audit(cxt, status)
494 #endif /* HAVE_LIBAUDIT */
496 static void log_lastlog(struct login_context
*cxt
)
505 fd
= open(_PATH_LASTLOG
, O_RDWR
, 0);
509 if (lseek(fd
, (off_t
) cxt
->pwd
->pw_uid
* sizeof(ll
), SEEK_SET
) == -1)
513 * Print last log message.
516 if (read(fd
, (char *)&ll
, sizeof(ll
)) == sizeof(ll
) &&
518 time_t ll_time
= (time_t) ll
.ll_time
;
520 printf(_("Last login: %.*s "), 24 - 5, ctime(&ll_time
));
521 if (*ll
.ll_host
!= '\0')
522 printf(_("from %.*s\n"),
523 (int)sizeof(ll
.ll_host
), ll
.ll_host
);
525 printf(_("on %.*s\n"),
526 (int)sizeof(ll
.ll_line
), ll
.ll_line
);
528 if (lseek(fd
, (off_t
) cxt
->pwd
->pw_uid
* sizeof(ll
), SEEK_SET
) == -1)
532 memset((char *)&ll
, 0, sizeof(ll
));
535 ll
.ll_time
= t
; /* ll_time is always 32bit */
538 xstrncpy(ll
.ll_line
, cxt
->tty_name
, sizeof(ll
.ll_line
));
540 xstrncpy(ll
.ll_host
, cxt
->hostname
, sizeof(ll
.ll_host
));
542 if (write_all(fd
, (char *)&ll
, sizeof(ll
)))
543 warn(_("write lastlog failed"));
549 * Update wtmp and utmp logs.
551 static void log_utmp(struct login_context
*cxt
)
557 utmpname(_PATH_UTMP
);
562 * login sometimes overwrites the runlevel entry in /var/run/utmp,
563 * confusing sysvinit. I added a test for the entry type, and the
564 * problem was gone. (In a runlevel entry, st_pid is not really a pid
565 * but some number calculated from the previous and current runlevel.)
566 * -- Michael Riepe <michael@stud.uni-hannover.de>
568 while ((utp
= getutent()))
569 if (utp
->ut_pid
== cxt
->pid
570 && utp
->ut_type
>= INIT_PROCESS
571 && utp
->ut_type
<= DEAD_PROCESS
)
574 /* If we can't find a pre-existing entry by pid, try by line.
575 * BSD network daemons may rely on this. */
576 if (utp
== NULL
&& cxt
->tty_name
) {
578 ut
.ut_type
= LOGIN_PROCESS
;
579 strncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
580 utp
= getutline(&ut
);
583 /* If we can't find a pre-existing entry by pid and line, try it by id.
584 * Very stupid telnetd daemons don't set up utmp at all. (kzak) */
585 if (utp
== NULL
&& cxt
->tty_number
) {
587 ut
.ut_type
= DEAD_PROCESS
;
588 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
593 memcpy(&ut
, utp
, sizeof(ut
));
595 /* some gettys/telnetds don't initialize utmp... */
596 memset(&ut
, 0, sizeof(ut
));
598 if (cxt
->tty_number
&& ut
.ut_id
[0] == 0)
599 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
601 strncpy(ut
.ut_user
, cxt
->username
, sizeof(ut
.ut_user
));
603 xstrncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
605 #ifdef _HAVE_UT_TV /* in <utmpbits.h> included by <utmp.h> */
606 gettimeofday(&tv
, NULL
);
607 ut
.ut_tv
.tv_sec
= tv
.tv_sec
;
608 ut
.ut_tv
.tv_usec
= tv
.tv_usec
;
613 ut
.ut_time
= t
; /* ut_time is not always a time_t */
614 /* glibc2 #defines it as ut_tv.tv_sec */
617 ut
.ut_type
= USER_PROCESS
;
618 ut
.ut_pid
= cxt
->pid
;
620 xstrncpy(ut
.ut_host
, cxt
->hostname
, sizeof(ut
.ut_host
));
621 if (*cxt
->hostaddress
)
622 memcpy(&ut
.ut_addr_v6
, cxt
->hostaddress
,
623 sizeof(ut
.ut_addr_v6
));
629 updwtmp(_PATH_WTMP
, &ut
);
632 static void log_syslog(struct login_context
*cxt
)
634 struct passwd
*pwd
= cxt
->pwd
;
639 if (!strncmp(cxt
->tty_name
, "ttyS", 4))
640 syslog(LOG_INFO
, _("DIALUP AT %s BY %s"),
641 cxt
->tty_name
, pwd
->pw_name
);
645 syslog(LOG_NOTICE
, _("ROOT LOGIN ON %s FROM %s"),
646 cxt
->tty_name
, cxt
->hostname
);
648 syslog(LOG_NOTICE
, _("ROOT LOGIN ON %s"), cxt
->tty_name
);
651 syslog(LOG_INFO
, _("LOGIN ON %s BY %s FROM %s"),
652 cxt
->tty_name
, pwd
->pw_name
, cxt
->hostname
);
654 syslog(LOG_INFO
, _("LOGIN ON %s BY %s"), cxt
->tty_name
,
659 static struct passwd
*get_passwd_entry(const char *username
,
663 struct passwd
*res
= NULL
;
667 if (!pwdbuf
|| !username
)
670 #ifdef _SC_GETPW_R_SIZE_MAX
672 long xsz
= sysconf(_SC_GETPW_R_SIZE_MAX
);
677 *pwdbuf
= xrealloc(*pwdbuf
, sz
);
679 x
= getpwnam_r(username
, pwd
, *pwdbuf
, sz
, &res
);
687 /* encapsulate stupid "void **" pam_get_item() API */
688 static int loginpam_get_username(pam_handle_t
*pamh
, char **name
)
690 const void *item
= (void *)*name
;
692 rc
= pam_get_item(pamh
, PAM_USER
, &item
);
693 *name
= (char *)item
;
697 static void loginpam_err(pam_handle_t
*pamh
, int retcode
)
699 const char *msg
= pam_strerror(pamh
, retcode
);
702 fprintf(stderr
, "\n%s\n", msg
);
703 syslog(LOG_ERR
, "%s", msg
);
705 pam_end(pamh
, retcode
);
706 sleepexit(EXIT_FAILURE
);
710 * Composes "<host> login: " string; or returns "login: " if -H is given.
712 static const char *loginpam_get_prompt(struct login_context
*cxt
)
715 char *prompt
, *dflt_prompt
= _("login: ");
718 if (cxt
->nohost
|| !(host
= get_thishost(cxt
, NULL
)))
721 sz
= strlen(host
) + 1 + strlen(dflt_prompt
) + 1;
723 prompt
= xmalloc(sz
);
724 snprintf(prompt
, sz
, "%s %s", host
, dflt_prompt
);
729 static pam_handle_t
*init_loginpam(struct login_context
*cxt
)
731 pam_handle_t
*pamh
= NULL
;
735 * username is initialized to NULL and if specified on the command line
736 * it is set. Therefore, we are safe not setting it to anything.
738 rc
= pam_start(cxt
->remote
? "remote" : "login",
739 cxt
->username
, &cxt
->conv
, &pamh
);
740 if (rc
!= PAM_SUCCESS
) {
741 warnx(_("PAM failure, aborting: %s"), pam_strerror(pamh
, rc
));
742 syslog(LOG_ERR
, _("Couldn't initialize PAM: %s"),
743 pam_strerror(pamh
, rc
));
744 sleepexit(EXIT_FAILURE
);
747 /* hostname & tty are either set to NULL or their correct values,
748 * depending on how much we know. */
749 rc
= pam_set_item(pamh
, PAM_RHOST
, cxt
->hostname
);
750 if (is_pam_failure(rc
))
751 loginpam_err(pamh
, rc
);
753 rc
= pam_set_item(pamh
, PAM_TTY
, cxt
->tty_name
);
754 if (is_pam_failure(rc
))
755 loginpam_err(pamh
, rc
);
758 * Andrew.Taylor@cal.montage.ca: Provide a user prompt to PAM so that
759 * the "login: " prompt gets localized. Unfortunately, PAM doesn't have
760 * an interface to specify the "Password: " string (yet).
762 rc
= pam_set_item(pamh
, PAM_USER_PROMPT
, loginpam_get_prompt(cxt
));
763 if (is_pam_failure(rc
))
764 loginpam_err(pamh
, rc
);
766 /* We don't need the original username. We have to follow PAM. */
768 cxt
->username
= NULL
;
774 static void loginpam_auth(struct login_context
*cxt
)
776 int rc
, show_unknown
;
777 unsigned int retries
, failcount
= 0;
778 const char *hostname
= cxt
->hostname
? cxt
->hostname
:
779 cxt
->tty_name
? cxt
->tty_name
: "<unknown>";
780 pam_handle_t
*pamh
= cxt
->pamh
;
782 /* if we didn't get a user on the command line, set it to NULL */
783 loginpam_get_username(pamh
, &cxt
->username
);
785 show_unknown
= getlogindefs_bool("LOG_UNKFAIL_ENAB", 0);
786 retries
= getlogindefs_num("LOGIN_RETRIES", LOGIN_MAX_TRIES
);
789 * There may be better ways to deal with some of these conditions, but
790 * at least this way I don't think we'll be giving away information...
792 * Perhaps someday we can trust that all PAM modules will pay attention
793 * to failure count and get rid of LOGIN_MAX_TRIES?
795 rc
= pam_authenticate(pamh
, 0);
797 while ((++failcount
< retries
) &&
798 ((rc
== PAM_AUTH_ERR
) ||
799 (rc
== PAM_USER_UNKNOWN
) ||
800 (rc
== PAM_CRED_INSUFFICIENT
) ||
801 (rc
== PAM_AUTHINFO_UNAVAIL
))) {
803 if (rc
== PAM_USER_UNKNOWN
&& !show_unknown
)
805 * Logging unknown usernames may be a security issue if
806 * a user enters her password instead of her login name.
808 cxt
->username
= NULL
;
810 loginpam_get_username(pamh
, &cxt
->username
);
813 _("FAILED LOGIN %u FROM %s FOR %s, %s"),
815 cxt
->username
? cxt
->username
: "(unknown)",
816 pam_strerror(pamh
, rc
));
821 fprintf(stderr
, _("Login incorrect\n\n"));
823 pam_set_item(pamh
, PAM_USER
, NULL
);
824 rc
= pam_authenticate(pamh
, 0);
827 if (is_pam_failure(rc
)) {
829 if (rc
== PAM_USER_UNKNOWN
&& !show_unknown
)
830 cxt
->username
= NULL
;
832 loginpam_get_username(pamh
, &cxt
->username
);
834 if (rc
== PAM_MAXTRIES
)
836 _("TOO MANY LOGIN TRIES (%u) FROM %s FOR %s, %s"),
838 cxt
->username
? cxt
->username
: "(unknown)",
839 pam_strerror(pamh
, rc
));
842 _("FAILED LOGIN SESSION FROM %s FOR %s, %s"),
844 cxt
->username
? cxt
->username
: "(unknown)",
845 pam_strerror(pamh
, rc
));
850 fprintf(stderr
, _("\nLogin incorrect\n"));
852 sleepexit(EXIT_SUCCESS
);
856 static void loginpam_acct(struct login_context
*cxt
)
859 pam_handle_t
*pamh
= cxt
->pamh
;
861 rc
= pam_acct_mgmt(pamh
, 0);
863 if (rc
== PAM_NEW_AUTHTOK_REQD
)
864 rc
= pam_chauthtok(pamh
, PAM_CHANGE_EXPIRED_AUTHTOK
);
866 if (is_pam_failure(rc
))
867 loginpam_err(pamh
, rc
);
870 * Grab the user information out of the password file for future use.
871 * First get the username that we are actually using, though.
873 rc
= loginpam_get_username(pamh
, &cxt
->username
);
874 if (is_pam_failure(rc
))
875 loginpam_err(pamh
, rc
);
877 if (!cxt
->username
|| !*cxt
->username
) {
878 warnx(_("\nSession setup problem, abort."));
879 syslog(LOG_ERR
, _("NULL user name in %s:%d. Abort."),
880 __FUNCTION__
, __LINE__
);
881 pam_end(pamh
, PAM_SYSTEM_ERR
);
882 sleepexit(EXIT_FAILURE
);
887 * Note that the position of the pam_setcred() call is discussable:
889 * - the PAM docs recommend pam_setcred() before pam_open_session()
890 * - but the original RFC http://www.opengroup.org/rfc/mirror-rfc/rfc86.0.txt
891 * uses pam_setcred() after pam_open_session()
893 * The old login versions (before year 2011) followed the RFC. This is probably
894 * not optimal, because there could be a dependence between some session modules
895 * and the user's credentials.
897 * The best is probably to follow openssh and call pam_setcred() before and
898 * after pam_open_session(). -- kzak@redhat.com (18-Nov-2011)
901 static void loginpam_session(struct login_context
*cxt
)
904 pam_handle_t
*pamh
= cxt
->pamh
;
906 rc
= pam_setcred(pamh
, PAM_ESTABLISH_CRED
);
907 if (is_pam_failure(rc
))
908 loginpam_err(pamh
, rc
);
910 rc
= pam_open_session(pamh
, 0);
911 if (is_pam_failure(rc
)) {
912 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
913 loginpam_err(pamh
, rc
);
916 rc
= pam_setcred(pamh
, PAM_REINITIALIZE_CRED
);
917 if (is_pam_failure(rc
)) {
918 pam_close_session(pamh
, 0);
919 loginpam_err(pamh
, rc
);
924 * Detach the controlling terminal, fork, restore syslog stuff, and create
927 static void fork_session(struct login_context
*cxt
)
929 struct sigaction sa
, oldsa_hup
, oldsa_term
;
931 signal(SIGALRM
, SIG_DFL
);
932 signal(SIGQUIT
, SIG_DFL
);
933 signal(SIGTSTP
, SIG_IGN
);
935 memset(&sa
, 0, sizeof(sa
));
936 sa
.sa_handler
= SIG_IGN
;
937 sigaction(SIGINT
, &sa
, NULL
);
939 sigaction(SIGHUP
, &sa
, &oldsa_hup
); /* ignore when TIOCNOTTY */
942 * Detach the controlling tty.
943 * We don't need the tty in a parent who only waits for a child.
944 * The child calls setsid() that detaches from the tty as well.
946 ioctl(0, TIOCNOTTY
, NULL
);
949 * We have to beware of SIGTERM, because leaving a PAM session
950 * without pam_close_session() is a pretty bad thing.
952 sa
.sa_handler
= sig_handler
;
953 sigaction(SIGHUP
, &sa
, NULL
);
954 sigaction(SIGTERM
, &sa
, &oldsa_term
);
959 * We must fork before setuid(), because we need to call
960 * pam_close_session() as root.
964 warn(_("fork failed"));
966 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
967 pam_end(cxt
->pamh
, pam_close_session(cxt
->pamh
, 0));
968 sleepexit(EXIT_FAILURE
);
973 * parent - wait for child to finish, then clean up session
978 sa
.sa_handler
= SIG_IGN
;
979 sigaction(SIGQUIT
, &sa
, NULL
);
980 sigaction(SIGINT
, &sa
, NULL
);
982 /* wait as long as any child is there */
983 while (wait(NULL
) == -1 && errno
== EINTR
) ;
984 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
);
986 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
987 pam_end(cxt
->pamh
, pam_close_session(cxt
->pamh
, 0));
994 sigaction(SIGHUP
, &oldsa_hup
, NULL
); /* restore old state */
995 sigaction(SIGTERM
, &oldsa_term
, NULL
);
1000 * Problem: if the user's shell is a shell like ash that doesn't do
1001 * setsid() or setpgrp(), then a ctrl-\, sending SIGQUIT to every
1002 * process in the pgrp, will kill us.
1005 /* start new session */
1008 /* make sure we have a controlling tty */
1009 open_tty(cxt
->tty_path
);
1010 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
); /* reopen */
1013 * TIOCSCTTY: steal tty from other process group.
1015 if (ioctl(0, TIOCSCTTY
, 1))
1016 syslog(LOG_ERR
, _("TIOCSCTTY failed: %m"));
1017 signal(SIGINT
, SIG_DFL
);
1021 * Initialize $TERM, $HOME, ...
1023 static void init_environ(struct login_context
*cxt
)
1025 struct passwd
*pwd
= cxt
->pwd
;
1026 char *termenv
= NULL
, **env
;
1030 termenv
= getenv("TERM");
1031 termenv
= termenv
? xstrdup(termenv
) : "dumb";
1033 /* destroy environment unless user has requested preservation (-p) */
1034 if (!cxt
->keep_env
) {
1035 environ
= (char **) xmalloc(sizeof(char *));
1036 memset(environ
, 0, sizeof(char *));
1039 setenv("HOME", pwd
->pw_dir
, 0); /* legal to override */
1040 setenv("USER", pwd
->pw_name
, 1);
1041 setenv("SHELL", pwd
->pw_shell
, 1);
1042 setenv("TERM", termenv
, 1);
1045 logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH
);
1047 else if (logindefs_setenv("PATH", "ENV_ROOTPATH", NULL
) != 0)
1048 logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT
);
1050 /* mailx will give a funny error msg if you forget this one */
1051 len
= snprintf(tmp
, sizeof(tmp
), "%s/%s", _PATH_MAILDIR
, pwd
->pw_name
);
1052 if (len
> 0 && (size_t) len
+ 1 <= sizeof(tmp
))
1053 setenv("MAIL", tmp
, 0);
1055 /* LOGNAME is not documented in login(1) but HP-UX 6.5 does it. We'll
1056 * not allow modifying it.
1058 setenv("LOGNAME", pwd
->pw_name
, 1);
1060 env
= pam_getenvlist(cxt
->pamh
);
1061 for (i
= 0; env
&& env
[i
]; i
++)
1066 * This is called for the -h option, initializes cxt->{hostname,hostaddress}.
1068 static void init_remote_info(struct login_context
*cxt
, char *remotehost
)
1072 struct addrinfo hints
, *info
= NULL
;
1076 get_thishost(cxt
, &domain
);
1078 if (domain
&& (p
= strchr(remotehost
, '.')) &&
1079 strcasecmp(p
+ 1, domain
) == 0)
1082 cxt
->hostname
= xstrdup(remotehost
);
1084 memset(&hints
, 0, sizeof(hints
));
1085 hints
.ai_flags
= AI_ADDRCONFIG
;
1086 cxt
->hostaddress
[0] = 0;
1088 if (getaddrinfo(cxt
->hostname
, NULL
, &hints
, &info
) == 0 && info
) {
1089 if (info
->ai_family
== AF_INET
) {
1090 struct sockaddr_in
*sa
=
1091 (struct sockaddr_in
*) info
->ai_addr
;
1093 memcpy(cxt
->hostaddress
, &(sa
->sin_addr
), sizeof(sa
->sin_addr
));
1095 } else if (info
->ai_family
== AF_INET6
) {
1096 struct sockaddr_in6
*sa
=
1097 (struct sockaddr_in6
*) info
->ai_addr
;
1099 memcpy(cxt
->hostaddress
, &(sa
->sin6_addr
), sizeof(sa
->sin6_addr
));
1105 int main(int argc
, char **argv
)
1109 char *childArgv
[10];
1114 char *pwdbuf
= NULL
;
1115 struct passwd
*pwd
= NULL
, _pwd
;
1117 struct login_context cxt
= {
1118 .tty_mode
= TTY_MODE
, /* tty chmod() */
1119 .pid
= getpid(), /* PID */
1120 .conv
= { misc_conv
, NULL
} /* PAM conversation function */
1123 timeout
= (unsigned int)getlogindefs_num("LOGIN_TIMEOUT", LOGIN_TIMEOUT
);
1125 signal(SIGALRM
, timedout
);
1126 siginterrupt(SIGALRM
, 1); /* we have to interrupt syscalls like ioclt() */
1128 signal(SIGQUIT
, SIG_IGN
);
1129 signal(SIGINT
, SIG_IGN
);
1131 setlocale(LC_ALL
, "");
1132 bindtextdomain(PACKAGE
, LOCALEDIR
);
1133 textdomain(PACKAGE
);
1135 setpriority(PRIO_PROCESS
, 0, 0);
1136 initproctitle(argc
, argv
);
1139 * -p is used by getty to tell login not to destroy the environment
1140 * -f is used to skip a second login authentication
1141 * -h is used by other servers to pass the name of the remote
1142 * host to login so that it may be placed in utmp and wtmp
1144 while ((c
= getopt(argc
, argv
, "fHh:pV")) != -1)
1157 _("login: -h is for superuser only\n"));
1160 init_remote_info(&cxt
, optarg
);
1168 printf(UTIL_LINUX_VERSION
);
1169 return EXIT_SUCCESS
;
1172 fprintf(stderr
, _("Usage: login [-p] [-h <host>] [-H] [[-f] <username>]\n"));
1180 cxt
.username
= xstrdup(p
);
1182 /* Wipe the name - some people mistype their password here. */
1183 /* (Of course we are too late, but perhaps this helps a little...) */
1188 for (cnt
= get_fd_tabsize() - 1; cnt
> 2; cnt
--)
1191 setpgrp(); /* set pgid to pid this means that setsid() will fail */
1194 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
);
1196 init_loginpam(&cxt
);
1198 /* login -f, then the user has already been authenticated */
1199 cxt
.noauth
= cxt
.noauth
&& getuid() == 0 ? 1 : 0;
1202 loginpam_auth(&cxt
);
1205 * Authentication may be skipped (for example, during krlogin, rlogin,
1206 * etc...), but it doesn't mean that we can skip other account checks.
1207 * The account could be disabled or the password has expired (although
1208 * the kerberos ticket is valid). -- kzak@redhat.com (22-Feb-2006)
1210 loginpam_acct(&cxt
);
1212 if (!(cxt
.pwd
= get_passwd_entry(cxt
.username
, &pwdbuf
, &_pwd
))) {
1213 warnx(_("\nSession setup problem, abort."));
1214 syslog(LOG_ERR
, _("Invalid user name \"%s\" in %s:%d. Abort."),
1215 cxt
.username
, __FUNCTION__
, __LINE__
);
1216 pam_end(cxt
.pamh
, PAM_SYSTEM_ERR
);
1217 sleepexit(EXIT_FAILURE
);
1221 cxt
.username
= pwd
->pw_name
;
1224 * Initialize the supplementary group list. This should be done before
1225 * pam_setcred, because PAM modules might add groups during that call.
1227 * For root we don't call initgroups, instead we call setgroups with
1228 * group 0. This avoids the need to step through the whole group file,
1229 * which can cause problems if NIS, NIS+, LDAP or something similar
1230 * is used and the machine has network problems.
1232 retcode
= pwd
->pw_uid
? initgroups(cxt
.username
, pwd
->pw_gid
) : /* user */
1233 setgroups(0, NULL
); /* root */
1235 syslog(LOG_ERR
, _("groups initialization failed: %m"));
1236 warnx(_("\nSession setup problem, abort."));
1237 pam_end(cxt
.pamh
, PAM_SYSTEM_ERR
);
1238 sleepexit(EXIT_FAILURE
);
1242 * Open PAM session (after successful authentication and account check).
1244 loginpam_session(&cxt
);
1246 /* committed to login -- turn off timeout */
1247 alarm((unsigned int)0);
1251 cxt
.quiet
= get_hushlogin_status(pwd
);
1259 if (setgid(pwd
->pw_gid
) < 0 && pwd
->pw_gid
) {
1260 syslog(LOG_ALERT
, _("setgid() failed"));
1264 if (pwd
->pw_shell
== NULL
|| *pwd
->pw_shell
== '\0')
1265 pwd
->pw_shell
= _PATH_BSHELL
;
1267 init_environ(&cxt
); /* init $HOME, $TERM ... */
1269 setproctitle("login", cxt
.username
);
1276 #ifdef LOGIN_STAT_MAIL
1278 * This turns out to be a bad idea: when the mail spool
1279 * is NFS mounted, and the NFS connection hangs, the
1280 * login hangs, even root cannot login.
1281 * Checking for mail should be done from the shell.
1287 mail
= getenv("MAIL");
1288 if (mail
&& stat(mail
, &st
) == 0 && st
.st_size
!= 0) {
1289 if (st
.st_mtime
> st
.st_atime
)
1290 printf(_("You have new mail.\n"));
1292 printf(_("You have mail.\n"));
1299 * Detach the controlling terminal, fork, and create a new session
1300 * and reinitialize syslog stuff.
1304 /* discard permissions last so we can't get killed and drop core */
1305 if (setuid(pwd
->pw_uid
) < 0 && pwd
->pw_uid
) {
1306 syslog(LOG_ALERT
, _("setuid() failed"));
1310 /* wait until here to change directory! */
1311 if (chdir(pwd
->pw_dir
) < 0) {
1312 warn(_("%s: change directory failed"), pwd
->pw_dir
);
1314 if (!getlogindefs_bool("DEFAULT_HOME", 1))
1319 printf(_("Logging in with home = \"/\".\n"));
1322 /* if the shell field has a space: treat it like a shell script */
1323 if (strchr(pwd
->pw_shell
, ' ')) {
1324 buff
= xmalloc(strlen(pwd
->pw_shell
) + 6);
1326 strcpy(buff
, "exec ");
1327 strcat(buff
, pwd
->pw_shell
);
1328 childArgv
[childArgc
++] = "/bin/sh";
1329 childArgv
[childArgc
++] = "-sh";
1330 childArgv
[childArgc
++] = "-c";
1331 childArgv
[childArgc
++] = buff
;
1333 char tbuf
[PATH_MAX
+ 2], *p
;
1336 xstrncpy(tbuf
+ 1, ((p
= strrchr(pwd
->pw_shell
, '/')) ?
1337 p
+ 1 : pwd
->pw_shell
), sizeof(tbuf
) - 1);
1339 childArgv
[childArgc
++] = pwd
->pw_shell
;
1340 childArgv
[childArgc
++] = xstrdup(tbuf
);
1343 childArgv
[childArgc
++] = NULL
;
1345 execvp(childArgv
[0], childArgv
+ 1);
1347 if (!strcmp(childArgv
[0], "/bin/sh"))
1348 warn(_("couldn't exec shell script"));
1350 warn(_("no shell"));