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 #ifdef HAVE_LINUX_MAJOR_H
52 # include <linux/major.h>
55 #include <security/pam_appl.h>
56 #ifdef HAVE_SECURITY_PAM_MISC_H
57 # include <security/pam_misc.h>
58 #elif defined(HAVE_SECURITY_OPENPAM_H)
59 # include <security/openpam.h>
61 #include <sys/sendfile.h>
64 # include <libaudit.h>
68 #include "setproctitle.h"
69 #include "pathnames.h"
74 #include "fileutils.h"
77 #include "logindefs.h"
79 #define is_pam_failure(_rc) ((_rc) != PAM_SUCCESS)
81 #define LOGIN_MAX_TRIES 3
82 #define LOGIN_EXIT_TIMEOUT 5
83 #define LOGIN_TIMEOUT 60
86 # define TTY_MODE 0620
88 # define TTY_MODE 0600
91 #define TTYGRPNAME "tty" /* name of group to own ttys */
92 #define VCS_PATH_MAX 64
95 * Login control struct
97 struct login_context
{
98 const char *tty_path
; /* ttyname() return value */
99 const char *tty_name
; /* tty_path without /dev prefix */
100 const char *tty_number
; /* end of the tty_path */
101 mode_t tty_mode
; /* chmod() mode */
103 char *username
; /* from command line or PAM */
105 struct passwd
*pwd
; /* user info */
107 pam_handle_t
*pamh
; /* PAM handler */
108 struct pam_conv conv
; /* PAM conversation */
110 #ifdef LOGIN_CHOWN_VCS
111 char vcsn
[VCS_PATH_MAX
]; /* virtual console name */
112 char vcsan
[VCS_PATH_MAX
];
115 char *thishost
; /* this machine */
116 char *thisdomain
; /* this machine's domain */
117 char *hostname
; /* remote machine */
118 char hostaddress
[16]; /* remote address */
121 int quiet
; /* 1 if hush file exists */
123 unsigned int remote
:1, /* login -h */
124 nohost
:1, /* login -H */
125 noauth
:1, /* login -f */
126 keep_env
:1; /* login -p */
130 * This bounds the time given to login. Not a define, so it can
131 * be patched on machines where it's too small.
133 static unsigned int timeout
= LOGIN_TIMEOUT
;
134 static int child_pid
= 0;
135 static volatile int got_sig
= 0;
137 #ifdef LOGIN_CHOWN_VCS
138 /* true if the filedescriptor fd is a console tty, very Linux specific */
139 static int is_consoletty(int fd
)
143 if ((fstat(fd
, &stb
) >= 0)
144 && (major(stb
.st_rdev
) == TTY_MAJOR
)
145 && (minor(stb
.st_rdev
) < 64)) {
154 * Robert Ambrose writes:
155 * A couple of my users have a problem with login processes hanging around
156 * soaking up pts's. What they seem to hung up on is trying to write out the
157 * message 'Login timed out after %d seconds' when the connection has already
159 * What I did was add a second timeout while trying to write the message, so
160 * the process just exits if the second timeout expires.
162 static void __attribute__ ((__noreturn__
))
163 timedout2(int sig
__attribute__ ((__unused__
)))
170 tcsetattr(0, TCSANOW
, &ti
);
171 exit(EXIT_SUCCESS
); /* %% */
174 static void timedout(int sig
__attribute__ ((__unused__
)))
176 signal(SIGALRM
, timedout2
);
178 /* TRANSLATORS: The standard value for %u is 60. */
179 warnx(_("timed out after %u seconds"), timeout
);
180 signal(SIGALRM
, SIG_IGN
);
186 * This handler allows to inform a shell about signals to login. If you have
187 * (root) permissions, you can kill all login children by one signal to the
190 * Also, a parent who is session leader is able (before setsid() in the child)
191 * to inform the child when the controlling tty goes away (e.g. modem hangup).
193 static void sig_handler(int signal
)
196 kill(-child_pid
, signal
);
199 if (signal
== SIGTERM
)
200 kill(-child_pid
, SIGHUP
); /* because the shell often ignores SIGTERM */
204 * Let us delay all exit() calls when the user is not authenticated
205 * or the session not fully initialized (loginpam_session()).
207 static void __attribute__ ((__noreturn__
)) sleepexit(int eval
)
209 sleep((unsigned int)getlogindefs_num("FAIL_DELAY", LOGIN_EXIT_TIMEOUT
));
213 static const char *get_thishost(struct login_context
*cxt
, const char **domain
)
215 if (!cxt
->thishost
) {
216 cxt
->thishost
= xgethostname();
217 if (!cxt
->thishost
) {
222 cxt
->thisdomain
= strchr(cxt
->thishost
, '.');
224 *cxt
->thisdomain
++ = '\0';
228 *domain
= cxt
->thisdomain
;
229 return cxt
->thishost
;
233 * Output the /etc/motd file.
235 * It determines the name of a login announcement file and outputs it to the
236 * user's terminal at login time. The MOTD_FILE configuration option is a
237 * colon-delimited list of filenames. An empty MOTD_FILE option disables
238 * message-of-the-day printing completely.
240 static void motd(void)
242 char *motdlist
, *motdfile
;
245 mb
= getlogindefs_str("MOTD_FILE", _PATH_MOTDFILE
);
249 motdlist
= xstrdup(mb
);
251 for (motdfile
= strtok(motdlist
, ":"); motdfile
;
252 motdfile
= strtok(NULL
, ":")) {
257 fd
= open(motdfile
, O_RDONLY
, 0);
260 if (!fstat(fd
, &st
) && st
.st_size
)
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() won't 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
)
428 #if defined(_HAVE_UT_TV) /* in <utmpbits.h> included by <utmp.h> */
432 memset(&ut
, 0, sizeof(ut
));
435 cxt
->username
? cxt
->username
: "(unknown)",
439 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
441 xstrncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
443 #if defined(_HAVE_UT_TV) /* in <utmpbits.h> included by <utmp.h> */
444 gettimeofday(&tv
, NULL
);
445 ut
.ut_tv
.tv_sec
= tv
.tv_sec
;
446 ut
.ut_tv
.tv_usec
= tv
.tv_usec
;
451 ut
.ut_time
= t
; /* ut_time is not always a time_t */
455 ut
.ut_type
= LOGIN_PROCESS
; /* XXX doesn't matter */
456 ut
.ut_pid
= cxt
->pid
;
459 xstrncpy(ut
.ut_host
, cxt
->hostname
, sizeof(ut
.ut_host
));
460 if (*cxt
->hostaddress
)
461 memcpy(&ut
.ut_addr_v6
, cxt
->hostaddress
,
462 sizeof(ut
.ut_addr_v6
));
465 updwtmp(_PATH_BTMP
, &ut
);
470 static void log_audit(struct login_context
*cxt
, int status
)
473 struct passwd
*pwd
= cxt
->pwd
;
475 audit_fd
= audit_open();
478 if (!pwd
&& cxt
->username
)
479 pwd
= getpwnam(cxt
->username
);
481 audit_log_acct_message(audit_fd
,
485 cxt
->username
? cxt
->username
: "(unknown)",
486 pwd
? pwd
->pw_uid
: (unsigned int) -1,
494 #else /* !HAVE_LIBAUDIT */
495 # define log_audit(cxt, status)
496 #endif /* HAVE_LIBAUDIT */
498 static void log_lastlog(struct login_context
*cxt
)
500 struct sigaction sa
, oldsa_xfsz
;
508 /* lastlog is huge on systems with large UIDs, ignore SIGXFSZ */
509 memset(&sa
, 0, sizeof(sa
));
510 sa
.sa_handler
= SIG_IGN
;
511 sigaction(SIGXFSZ
, &sa
, &oldsa_xfsz
);
513 fd
= open(_PATH_LASTLOG
, O_RDWR
, 0);
517 if (lseek(fd
, (off_t
) cxt
->pwd
->pw_uid
* sizeof(ll
), SEEK_SET
) == -1)
521 * Print last log message.
524 if (read(fd
, (char *)&ll
, sizeof(ll
)) == sizeof(ll
) &&
526 time_t ll_time
= (time_t) ll
.ll_time
;
528 printf(_("Last login: %.*s "), 24 - 5, ctime(&ll_time
));
529 if (*ll
.ll_host
!= '\0')
530 printf(_("from %.*s\n"),
531 (int)sizeof(ll
.ll_host
), ll
.ll_host
);
533 printf(_("on %.*s\n"),
534 (int)sizeof(ll
.ll_line
), ll
.ll_line
);
536 if (lseek(fd
, (off_t
) cxt
->pwd
->pw_uid
* sizeof(ll
), SEEK_SET
) == -1)
540 memset((char *)&ll
, 0, sizeof(ll
));
543 ll
.ll_time
= t
; /* ll_time is always 32bit */
546 xstrncpy(ll
.ll_line
, cxt
->tty_name
, sizeof(ll
.ll_line
));
548 xstrncpy(ll
.ll_host
, cxt
->hostname
, sizeof(ll
.ll_host
));
550 if (write_all(fd
, (char *)&ll
, sizeof(ll
)))
551 warn(_("write lastlog failed"));
556 sigaction(SIGXFSZ
, &oldsa_xfsz
, NULL
); /* restore original setting */
560 * Update wtmp and utmp logs.
562 static void log_utmp(struct login_context
*cxt
)
568 utmpname(_PATH_UTMP
);
573 * login sometimes overwrites the runlevel entry in /var/run/utmp,
574 * confusing sysvinit. I added a test for the entry type, and the
575 * problem was gone. (In a runlevel entry, st_pid is not really a pid
576 * but some number calculated from the previous and current runlevel.)
577 * -- Michael Riepe <michael@stud.uni-hannover.de>
579 while ((utp
= getutent()))
580 if (utp
->ut_pid
== cxt
->pid
581 && utp
->ut_type
>= INIT_PROCESS
582 && utp
->ut_type
<= DEAD_PROCESS
)
585 /* If we can't find a pre-existing entry by pid, try by line.
586 * BSD network daemons may rely on this. */
587 if (utp
== NULL
&& cxt
->tty_name
) {
589 ut
.ut_type
= LOGIN_PROCESS
;
590 strncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
591 utp
= getutline(&ut
);
594 /* If we can't find a pre-existing entry by pid and line, try it by id.
595 * Very stupid telnetd daemons don't set up utmp at all. (kzak) */
596 if (utp
== NULL
&& cxt
->tty_number
) {
598 ut
.ut_type
= DEAD_PROCESS
;
599 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
604 memcpy(&ut
, utp
, sizeof(ut
));
606 /* some gettys/telnetds don't initialize utmp... */
607 memset(&ut
, 0, sizeof(ut
));
609 if (cxt
->tty_number
&& ut
.ut_id
[0] == 0)
610 strncpy(ut
.ut_id
, cxt
->tty_number
, sizeof(ut
.ut_id
));
612 strncpy(ut
.ut_user
, cxt
->username
, sizeof(ut
.ut_user
));
614 xstrncpy(ut
.ut_line
, cxt
->tty_name
, sizeof(ut
.ut_line
));
616 #ifdef _HAVE_UT_TV /* in <utmpbits.h> included by <utmp.h> */
617 gettimeofday(&tv
, NULL
);
618 ut
.ut_tv
.tv_sec
= tv
.tv_sec
;
619 ut
.ut_tv
.tv_usec
= tv
.tv_usec
;
624 ut
.ut_time
= t
; /* ut_time is not always a time_t */
625 /* glibc2 #defines it as ut_tv.tv_sec */
628 ut
.ut_type
= USER_PROCESS
;
629 ut
.ut_pid
= cxt
->pid
;
631 xstrncpy(ut
.ut_host
, cxt
->hostname
, sizeof(ut
.ut_host
));
632 if (*cxt
->hostaddress
)
633 memcpy(&ut
.ut_addr_v6
, cxt
->hostaddress
,
634 sizeof(ut
.ut_addr_v6
));
640 updwtmp(_PATH_WTMP
, &ut
);
643 static void log_syslog(struct login_context
*cxt
)
645 struct passwd
*pwd
= cxt
->pwd
;
650 if (!strncmp(cxt
->tty_name
, "ttyS", 4))
651 syslog(LOG_INFO
, _("DIALUP AT %s BY %s"),
652 cxt
->tty_name
, pwd
->pw_name
);
656 syslog(LOG_NOTICE
, _("ROOT LOGIN ON %s FROM %s"),
657 cxt
->tty_name
, cxt
->hostname
);
659 syslog(LOG_NOTICE
, _("ROOT LOGIN ON %s"), cxt
->tty_name
);
662 syslog(LOG_INFO
, _("LOGIN ON %s BY %s FROM %s"),
663 cxt
->tty_name
, pwd
->pw_name
, cxt
->hostname
);
665 syslog(LOG_INFO
, _("LOGIN ON %s BY %s"), cxt
->tty_name
,
670 static struct passwd
*get_passwd_entry(const char *username
,
674 struct passwd
*res
= NULL
;
677 if (!pwdbuf
|| !username
)
680 *pwdbuf
= xrealloc(*pwdbuf
, UL_GETPW_BUFSIZ
);
682 x
= getpwnam_r(username
, pwd
, *pwdbuf
, UL_GETPW_BUFSIZ
, &res
);
690 /* encapsulate stupid "void **" pam_get_item() API */
691 static int loginpam_get_username(pam_handle_t
*pamh
, char **name
)
693 const void *item
= (void *)*name
;
695 rc
= pam_get_item(pamh
, PAM_USER
, &item
);
696 *name
= (char *)item
;
700 static void loginpam_err(pam_handle_t
*pamh
, int retcode
)
702 const char *msg
= pam_strerror(pamh
, retcode
);
705 fprintf(stderr
, "\n%s\n", msg
);
706 syslog(LOG_ERR
, "%s", msg
);
708 pam_end(pamh
, retcode
);
709 sleepexit(EXIT_FAILURE
);
713 * Composes "<host> login: " string; or returns "login: " if -H is given.
715 static const char *loginpam_get_prompt(struct login_context
*cxt
)
718 char *prompt
, *dflt_prompt
= _("login: ");
721 if (cxt
->nohost
|| !(host
= get_thishost(cxt
, NULL
)))
724 sz
= strlen(host
) + 1 + strlen(dflt_prompt
) + 1;
726 prompt
= xmalloc(sz
);
727 snprintf(prompt
, sz
, "%s %s", host
, dflt_prompt
);
732 static pam_handle_t
*init_loginpam(struct login_context
*cxt
)
734 pam_handle_t
*pamh
= NULL
;
738 * username is initialized to NULL and if specified on the command line
739 * it is set. Therefore, we are safe not setting it to anything.
741 rc
= pam_start(cxt
->remote
? "remote" : "login",
742 cxt
->username
, &cxt
->conv
, &pamh
);
743 if (rc
!= PAM_SUCCESS
) {
744 warnx(_("PAM failure, aborting: %s"), pam_strerror(pamh
, rc
));
745 syslog(LOG_ERR
, _("Couldn't initialize PAM: %s"),
746 pam_strerror(pamh
, rc
));
747 sleepexit(EXIT_FAILURE
);
750 /* hostname & tty are either set to NULL or their correct values,
751 * depending on how much we know. */
752 rc
= pam_set_item(pamh
, PAM_RHOST
, cxt
->hostname
);
753 if (is_pam_failure(rc
))
754 loginpam_err(pamh
, rc
);
756 rc
= pam_set_item(pamh
, PAM_TTY
, cxt
->tty_name
);
757 if (is_pam_failure(rc
))
758 loginpam_err(pamh
, rc
);
761 * Andrew.Taylor@cal.montage.ca: Provide a user prompt to PAM so that
762 * the "login: " prompt gets localized. Unfortunately, PAM doesn't have
763 * an interface to specify the "Password: " string (yet).
765 rc
= pam_set_item(pamh
, PAM_USER_PROMPT
, loginpam_get_prompt(cxt
));
766 if (is_pam_failure(rc
))
767 loginpam_err(pamh
, rc
);
769 /* We don't need the original username. We have to follow PAM. */
771 cxt
->username
= NULL
;
777 static void loginpam_auth(struct login_context
*cxt
)
779 int rc
, show_unknown
;
780 unsigned int retries
, failcount
= 0;
781 const char *hostname
= cxt
->hostname
? cxt
->hostname
:
782 cxt
->tty_name
? cxt
->tty_name
: "<unknown>";
783 pam_handle_t
*pamh
= cxt
->pamh
;
785 /* if we didn't get a user on the command line, set it to NULL */
786 loginpam_get_username(pamh
, &cxt
->username
);
788 show_unknown
= getlogindefs_bool("LOG_UNKFAIL_ENAB", 0);
789 retries
= getlogindefs_num("LOGIN_RETRIES", LOGIN_MAX_TRIES
);
792 * There may be better ways to deal with some of these conditions, but
793 * at least this way I don't think we'll be giving away information...
795 * Perhaps someday we can trust that all PAM modules will pay attention
796 * to failure count and get rid of LOGIN_MAX_TRIES?
798 rc
= pam_authenticate(pamh
, 0);
800 while ((++failcount
< retries
) &&
801 ((rc
== PAM_AUTH_ERR
) ||
802 (rc
== PAM_USER_UNKNOWN
) ||
803 (rc
== PAM_CRED_INSUFFICIENT
) ||
804 (rc
== PAM_AUTHINFO_UNAVAIL
))) {
806 if (rc
== PAM_USER_UNKNOWN
&& !show_unknown
)
808 * Logging unknown usernames may be a security issue if
809 * a user enters her password instead of her login name.
811 cxt
->username
= NULL
;
813 loginpam_get_username(pamh
, &cxt
->username
);
816 _("FAILED LOGIN %u FROM %s FOR %s, %s"),
818 cxt
->username
? cxt
->username
: "(unknown)",
819 pam_strerror(pamh
, rc
));
824 fprintf(stderr
, _("Login incorrect\n\n"));
826 pam_set_item(pamh
, PAM_USER
, NULL
);
827 rc
= pam_authenticate(pamh
, 0);
830 if (is_pam_failure(rc
)) {
832 if (rc
== PAM_USER_UNKNOWN
&& !show_unknown
)
833 cxt
->username
= NULL
;
835 loginpam_get_username(pamh
, &cxt
->username
);
837 if (rc
== PAM_MAXTRIES
)
839 _("TOO MANY LOGIN TRIES (%u) FROM %s FOR %s, %s"),
841 cxt
->username
? cxt
->username
: "(unknown)",
842 pam_strerror(pamh
, rc
));
845 _("FAILED LOGIN SESSION FROM %s FOR %s, %s"),
847 cxt
->username
? cxt
->username
: "(unknown)",
848 pam_strerror(pamh
, rc
));
853 fprintf(stderr
, _("\nLogin incorrect\n"));
855 sleepexit(EXIT_SUCCESS
);
859 static void loginpam_acct(struct login_context
*cxt
)
862 pam_handle_t
*pamh
= cxt
->pamh
;
864 rc
= pam_acct_mgmt(pamh
, 0);
866 if (rc
== PAM_NEW_AUTHTOK_REQD
)
867 rc
= pam_chauthtok(pamh
, PAM_CHANGE_EXPIRED_AUTHTOK
);
869 if (is_pam_failure(rc
))
870 loginpam_err(pamh
, rc
);
873 * Grab the user information out of the password file for future use.
874 * First get the username that we are actually using, though.
876 rc
= loginpam_get_username(pamh
, &cxt
->username
);
877 if (is_pam_failure(rc
))
878 loginpam_err(pamh
, rc
);
880 if (!cxt
->username
|| !*cxt
->username
) {
881 warnx(_("\nSession setup problem, abort."));
882 syslog(LOG_ERR
, _("NULL user name in %s:%d. Abort."),
883 __FUNCTION__
, __LINE__
);
884 pam_end(pamh
, PAM_SYSTEM_ERR
);
885 sleepexit(EXIT_FAILURE
);
890 * Note that the position of the pam_setcred() call is discussable:
892 * - the PAM docs recommend pam_setcred() before pam_open_session()
893 * - but the original RFC http://www.opengroup.org/rfc/mirror-rfc/rfc86.0.txt
894 * uses pam_setcred() after pam_open_session()
896 * The old login versions (before year 2011) followed the RFC. This is probably
897 * not optimal, because there could be a dependence between some session modules
898 * and the user's credentials.
900 * The best is probably to follow openssh and call pam_setcred() before and
901 * after pam_open_session(). -- kzak@redhat.com (18-Nov-2011)
904 static void loginpam_session(struct login_context
*cxt
)
907 pam_handle_t
*pamh
= cxt
->pamh
;
909 rc
= pam_setcred(pamh
, PAM_ESTABLISH_CRED
);
910 if (is_pam_failure(rc
))
911 loginpam_err(pamh
, rc
);
913 rc
= pam_open_session(pamh
, 0);
914 if (is_pam_failure(rc
)) {
915 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
916 loginpam_err(pamh
, rc
);
919 rc
= pam_setcred(pamh
, PAM_REINITIALIZE_CRED
);
920 if (is_pam_failure(rc
)) {
921 pam_close_session(pamh
, 0);
922 loginpam_err(pamh
, rc
);
927 * Detach the controlling terminal, fork, restore syslog stuff, and create
930 static void fork_session(struct login_context
*cxt
)
932 struct sigaction sa
, oldsa_hup
, oldsa_term
;
934 signal(SIGALRM
, SIG_DFL
);
935 signal(SIGQUIT
, SIG_DFL
);
936 signal(SIGTSTP
, SIG_IGN
);
938 memset(&sa
, 0, sizeof(sa
));
939 sa
.sa_handler
= SIG_IGN
;
940 sigaction(SIGINT
, &sa
, NULL
);
942 sigaction(SIGHUP
, &sa
, &oldsa_hup
); /* ignore when TIOCNOTTY */
945 * Detach the controlling tty.
946 * We don't need the tty in a parent who only waits for a child.
947 * The child calls setsid() that detaches from the tty as well.
949 ioctl(0, TIOCNOTTY
, NULL
);
952 * We have to beware of SIGTERM, because leaving a PAM session
953 * without pam_close_session() is a pretty bad thing.
955 sa
.sa_handler
= sig_handler
;
956 sigaction(SIGHUP
, &sa
, NULL
);
957 sigaction(SIGTERM
, &sa
, &oldsa_term
);
962 * We must fork before setuid(), because we need to call
963 * pam_close_session() as root.
967 warn(_("fork failed"));
969 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
970 pam_end(cxt
->pamh
, pam_close_session(cxt
->pamh
, 0));
971 sleepexit(EXIT_FAILURE
);
976 * parent - wait for child to finish, then clean up session
981 sa
.sa_handler
= SIG_IGN
;
982 sigaction(SIGQUIT
, &sa
, NULL
);
983 sigaction(SIGINT
, &sa
, NULL
);
985 /* wait as long as any child is there */
986 while (wait(NULL
) == -1 && errno
== EINTR
) ;
987 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
);
989 pam_setcred(cxt
->pamh
, PAM_DELETE_CRED
);
990 pam_end(cxt
->pamh
, pam_close_session(cxt
->pamh
, 0));
997 sigaction(SIGHUP
, &oldsa_hup
, NULL
); /* restore old state */
998 sigaction(SIGTERM
, &oldsa_term
, NULL
);
1003 * Problem: if the user's shell is a shell like ash that doesn't do
1004 * setsid() or setpgrp(), then a ctrl-\, sending SIGQUIT to every
1005 * process in the pgrp, will kill us.
1008 /* start new session */
1011 /* make sure we have a controlling tty */
1012 open_tty(cxt
->tty_path
);
1013 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
); /* reopen */
1016 * TIOCSCTTY: steal tty from other process group.
1018 if (ioctl(0, TIOCSCTTY
, 1))
1019 syslog(LOG_ERR
, _("TIOCSCTTY failed: %m"));
1020 signal(SIGINT
, SIG_DFL
);
1024 * Initialize $TERM, $HOME, ...
1026 static void init_environ(struct login_context
*cxt
)
1028 struct passwd
*pwd
= cxt
->pwd
;
1029 char *termenv
, **env
;
1033 termenv
= getenv("TERM");
1035 termenv
= xstrdup(termenv
);
1037 /* destroy environment unless user has requested preservation (-p) */
1038 if (!cxt
->keep_env
) {
1039 environ
= xmalloc(sizeof(char *));
1040 memset(environ
, 0, sizeof(char *));
1043 setenv("HOME", pwd
->pw_dir
, 0); /* legal to override */
1044 setenv("USER", pwd
->pw_name
, 1);
1045 setenv("SHELL", pwd
->pw_shell
, 1);
1046 setenv("TERM", termenv
? termenv
: "dumb", 1);
1050 logindefs_setenv("PATH", "ENV_PATH", _PATH_DEFPATH
);
1052 else if (logindefs_setenv("PATH", "ENV_ROOTPATH", NULL
) != 0)
1053 logindefs_setenv("PATH", "ENV_SUPATH", _PATH_DEFPATH_ROOT
);
1055 /* mailx will give a funny error msg if you forget this one */
1056 len
= snprintf(tmp
, sizeof(tmp
), "%s/%s", _PATH_MAILDIR
, pwd
->pw_name
);
1057 if (len
> 0 && (size_t) len
< sizeof(tmp
))
1058 setenv("MAIL", tmp
, 0);
1060 /* LOGNAME is not documented in login(1) but HP-UX 6.5 does it. We'll
1061 * not allow modifying it.
1063 setenv("LOGNAME", pwd
->pw_name
, 1);
1065 env
= pam_getenvlist(cxt
->pamh
);
1066 for (i
= 0; env
&& env
[i
]; i
++)
1071 * This is called for the -h option, initializes cxt->{hostname,hostaddress}.
1073 static void init_remote_info(struct login_context
*cxt
, char *remotehost
)
1077 struct addrinfo hints
, *info
= NULL
;
1081 get_thishost(cxt
, &domain
);
1083 if (domain
&& (p
= strchr(remotehost
, '.')) &&
1084 strcasecmp(p
+ 1, domain
) == 0)
1087 cxt
->hostname
= xstrdup(remotehost
);
1089 memset(&hints
, 0, sizeof(hints
));
1090 hints
.ai_flags
= AI_ADDRCONFIG
;
1091 cxt
->hostaddress
[0] = 0;
1093 if (getaddrinfo(cxt
->hostname
, NULL
, &hints
, &info
) == 0 && info
) {
1094 if (info
->ai_family
== AF_INET
) {
1095 struct sockaddr_in
*sa
=
1096 (struct sockaddr_in
*) info
->ai_addr
;
1098 memcpy(cxt
->hostaddress
, &(sa
->sin_addr
), sizeof(sa
->sin_addr
));
1100 } else if (info
->ai_family
== AF_INET6
) {
1101 struct sockaddr_in6
*sa
=
1102 (struct sockaddr_in6
*) info
->ai_addr
;
1104 memcpy(cxt
->hostaddress
, &(sa
->sin6_addr
), sizeof(sa
->sin6_addr
));
1110 int main(int argc
, char **argv
)
1114 char *childArgv
[10];
1118 struct sigaction act
;
1120 char *pwdbuf
= NULL
;
1121 struct passwd
*pwd
= NULL
, _pwd
;
1123 struct login_context cxt
= {
1124 .tty_mode
= TTY_MODE
, /* tty chmod() */
1125 .pid
= getpid(), /* PID */
1126 #ifdef HAVE_SECURITY_PAM_MISC_H
1127 .conv
= { misc_conv
, NULL
} /* Linux-PAM conversation function */
1128 #elif defined(HAVE_SECURITY_OPENPAM_H)
1129 .conv
= { openpam_ttyconv
, NULL
} /* OpenPAM conversation function */
1134 timeout
= (unsigned int)getlogindefs_num("LOGIN_TIMEOUT", LOGIN_TIMEOUT
);
1136 signal(SIGALRM
, timedout
);
1137 (void) sigaction(SIGALRM
, NULL
, &act
);
1138 act
.sa_flags
&= ~SA_RESTART
;
1139 sigaction(SIGALRM
, &act
, NULL
);
1141 signal(SIGQUIT
, SIG_IGN
);
1142 signal(SIGINT
, SIG_IGN
);
1144 setlocale(LC_ALL
, "");
1145 bindtextdomain(PACKAGE
, LOCALEDIR
);
1146 textdomain(PACKAGE
);
1148 setpriority(PRIO_PROCESS
, 0, 0);
1149 initproctitle(argc
, argv
);
1152 * -p is used by getty to tell login not to destroy the environment
1153 * -f is used to skip a second login authentication
1154 * -h is used by other servers to pass the name of the remote
1155 * host to login so that it may be placed in utmp and wtmp
1157 while ((c
= getopt(argc
, argv
, "fHh:pV")) != -1)
1170 _("login: -h is for superuser only\n"));
1173 init_remote_info(&cxt
, optarg
);
1181 printf(UTIL_LINUX_VERSION
);
1182 return EXIT_SUCCESS
;
1185 fprintf(stderr
, _("Usage: login [-p] [-h <host>] [-H] [[-f] <username>]\n"));
1186 fputs(USAGE_SEPARATOR
, stderr
);
1187 fputs(_("Begin a session on the system.\n"), stderr
);
1195 cxt
.username
= xstrdup(p
);
1197 /* Wipe the name - some people mistype their password here. */
1198 /* (Of course we are too late, but perhaps this helps a little...) */
1203 for (cnt
= get_fd_tabsize() - 1; cnt
> 2; cnt
--)
1206 setpgrp(); /* set pgid to pid this means that setsid() will fail */
1209 openlog("login", LOG_ODELAY
, LOG_AUTHPRIV
);
1211 init_loginpam(&cxt
);
1213 /* login -f, then the user has already been authenticated */
1214 cxt
.noauth
= cxt
.noauth
&& getuid() == 0 ? 1 : 0;
1217 loginpam_auth(&cxt
);
1220 * Authentication may be skipped (for example, during krlogin, rlogin,
1221 * etc...), but it doesn't mean that we can skip other account checks.
1222 * The account could be disabled or the password has expired (although
1223 * the kerberos ticket is valid). -- kzak@redhat.com (22-Feb-2006)
1225 loginpam_acct(&cxt
);
1227 if (!(cxt
.pwd
= get_passwd_entry(cxt
.username
, &pwdbuf
, &_pwd
))) {
1228 warnx(_("\nSession setup problem, abort."));
1229 syslog(LOG_ERR
, _("Invalid user name \"%s\" in %s:%d. Abort."),
1230 cxt
.username
, __FUNCTION__
, __LINE__
);
1231 pam_end(cxt
.pamh
, PAM_SYSTEM_ERR
);
1232 sleepexit(EXIT_FAILURE
);
1236 cxt
.username
= pwd
->pw_name
;
1239 * Initialize the supplementary group list. This should be done before
1240 * pam_setcred, because PAM modules might add groups during that call.
1242 * For root we don't call initgroups, instead we call setgroups with
1243 * group 0. This avoids the need to step through the whole group file,
1244 * which can cause problems if NIS, NIS+, LDAP or something similar
1245 * is used and the machine has network problems.
1247 retcode
= pwd
->pw_uid
? initgroups(cxt
.username
, pwd
->pw_gid
) : /* user */
1248 setgroups(0, NULL
); /* root */
1250 syslog(LOG_ERR
, _("groups initialization failed: %m"));
1251 warnx(_("\nSession setup problem, abort."));
1252 pam_end(cxt
.pamh
, PAM_SYSTEM_ERR
);
1253 sleepexit(EXIT_FAILURE
);
1257 * Open PAM session (after successful authentication and account check).
1259 loginpam_session(&cxt
);
1261 /* committed to login -- turn off timeout */
1262 alarm((unsigned int)0);
1266 cxt
.quiet
= get_hushlogin_status(pwd
, 1);
1274 if (setgid(pwd
->pw_gid
) < 0 && pwd
->pw_gid
) {
1275 syslog(LOG_ALERT
, _("setgid() failed"));
1279 if (pwd
->pw_shell
== NULL
|| *pwd
->pw_shell
== '\0')
1280 pwd
->pw_shell
= _PATH_BSHELL
;
1282 init_environ(&cxt
); /* init $HOME, $TERM ... */
1284 setproctitle("login", cxt
.username
);
1291 #ifdef LOGIN_STAT_MAIL
1293 * This turns out to be a bad idea: when the mail spool
1294 * is NFS mounted, and the NFS connection hangs, the
1295 * login hangs, even root cannot login.
1296 * Checking for mail should be done from the shell.
1302 mail
= getenv("MAIL");
1303 if (mail
&& stat(mail
, &st
) == 0 && st
.st_size
!= 0) {
1304 if (st
.st_mtime
> st
.st_atime
)
1305 printf(_("You have new mail.\n"));
1307 printf(_("You have mail.\n"));
1314 * Detach the controlling terminal, fork, and create a new session
1315 * and reinitialize syslog stuff.
1319 /* discard permissions last so we can't get killed and drop core */
1320 if (setuid(pwd
->pw_uid
) < 0 && pwd
->pw_uid
) {
1321 syslog(LOG_ALERT
, _("setuid() failed"));
1325 /* wait until here to change directory! */
1326 if (chdir(pwd
->pw_dir
) < 0) {
1327 warn(_("%s: change directory failed"), pwd
->pw_dir
);
1329 if (!getlogindefs_bool("DEFAULT_HOME", 1))
1334 printf(_("Logging in with home = \"/\".\n"));
1337 /* if the shell field has a space: treat it like a shell script */
1338 if (strchr(pwd
->pw_shell
, ' ')) {
1339 buff
= xmalloc(strlen(pwd
->pw_shell
) + 6);
1341 strcpy(buff
, "exec ");
1342 strcat(buff
, pwd
->pw_shell
);
1343 childArgv
[childArgc
++] = "/bin/sh";
1344 childArgv
[childArgc
++] = "-sh";
1345 childArgv
[childArgc
++] = "-c";
1346 childArgv
[childArgc
++] = buff
;
1348 char tbuf
[PATH_MAX
+ 2], *p
;
1351 xstrncpy(tbuf
+ 1, ((p
= strrchr(pwd
->pw_shell
, '/')) ?
1352 p
+ 1 : pwd
->pw_shell
), sizeof(tbuf
) - 1);
1354 childArgv
[childArgc
++] = pwd
->pw_shell
;
1355 childArgv
[childArgc
++] = xstrdup(tbuf
);
1358 childArgv
[childArgc
++] = NULL
;
1360 execvp(childArgv
[0], childArgv
+ 1);
1362 if (!strcmp(childArgv
[0], "/bin/sh"))
1363 warn(_("couldn't exec shell script"));
1365 warn(_("no shell"));