2 * Copyright (c) 2002 Networks Associates Technology, Inc.
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * NAI Labs, the Security Research Division of Network Associates, Inc.
7 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
8 * DARPA CHATS research program.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
33 * Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
35 * Permission to use, copy, modify, and distribute this software for any
36 * purpose with or without fee is hereby granted, provided that the above
37 * copyright notice and this permission notice appear in all copies.
39 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
40 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
41 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
42 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
43 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
44 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
45 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
48 /* Based on FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des */
52 #include <sys/types.h>
63 #if defined(HAVE_SECURITY_PAM_APPL_H)
64 #include <security/pam_appl.h>
65 #elif defined (HAVE_PAM_PAM_APPL_H)
66 #include <pam/pam_appl.h>
69 /* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */
70 #ifdef PAM_SUN_CODEBASE
71 # define sshpam_const /* Solaris, HP-UX, SunOS */
73 # define sshpam_const const /* LinuxPAM, OpenPAM, AIX */
76 /* Ambiguity in spec: is it an array of pointers or a pointer to an array? */
77 #ifdef PAM_SUN_CODEBASE
78 # define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member)
80 # define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member)
96 #include "auth-options.h"
100 #include "monitor_wrap.h"
102 extern ServerOptions options
;
103 extern Buffer loginmsg
;
105 extern u_int utmp_len
;
107 /* so we don't silently change behaviour */
108 #ifdef USE_POSIX_THREADS
109 # error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK"
113 * Formerly known as USE_POSIX_THREADS, using this is completely unsupported
114 * and generally a bad idea. Use at own risk and do not expect support if
117 #ifdef UNSUPPORTED_POSIX_THREADS_HACK
120 * Avoid namespace clash when *not* using pthreads for systems *with*
121 * pthreads, which unconditionally define pthread_t via sys/types.h
124 typedef pthread_t sp_pthread_t
;
126 typedef pid_t sp_pthread_t
;
130 sp_pthread_t pam_thread
;
136 static void sshpam_free_ctx(void *);
137 static struct pam_ctxt
*cleanup_ctxt
;
139 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
141 * Simulate threads with processes.
144 static int sshpam_thread_status
= -1;
145 static mysig_t sshpam_oldsig
;
148 sshpam_sigchld_handler(int sig
)
150 signal(SIGCHLD
, SIG_DFL
);
151 if (cleanup_ctxt
== NULL
)
152 return; /* handler called after PAM cleanup, shouldn't happen */
153 if (waitpid(cleanup_ctxt
->pam_thread
, &sshpam_thread_status
, WNOHANG
)
155 /* PAM thread has not exitted, privsep slave must have */
156 kill(cleanup_ctxt
->pam_thread
, SIGTERM
);
157 while (waitpid(cleanup_ctxt
->pam_thread
,
158 &sshpam_thread_status
, 0) == -1) {
164 if (WIFSIGNALED(sshpam_thread_status
) &&
165 WTERMSIG(sshpam_thread_status
) == SIGTERM
)
166 return; /* terminated by pthread_cancel */
167 if (!WIFEXITED(sshpam_thread_status
))
168 sigdie("PAM: authentication thread exited unexpectedly");
169 if (WEXITSTATUS(sshpam_thread_status
) != 0)
170 sigdie("PAM: authentication thread exited uncleanly");
175 pthread_exit(void *value
)
182 pthread_create(sp_pthread_t
*thread
, const void *attr
,
183 void *(*thread_start
)(void *), void *arg
)
186 struct pam_ctxt
*ctx
= arg
;
188 sshpam_thread_status
= -1;
189 switch ((pid
= fork())) {
191 error("fork(): %s", strerror(errno
));
194 close(ctx
->pam_psock
);
200 close(ctx
->pam_csock
);
202 sshpam_oldsig
= signal(SIGCHLD
, sshpam_sigchld_handler
);
208 pthread_cancel(sp_pthread_t thread
)
210 signal(SIGCHLD
, sshpam_oldsig
);
211 return (kill(thread
, SIGTERM
));
216 pthread_join(sp_pthread_t thread
, void **value
)
220 if (sshpam_thread_status
!= -1)
221 return (sshpam_thread_status
);
222 signal(SIGCHLD
, sshpam_oldsig
);
223 while (waitpid(thread
, &status
, 0) == -1) {
226 fatal("%s: waitpid: %s", __func__
, strerror(errno
));
233 static pam_handle_t
*sshpam_handle
= NULL
;
234 static int sshpam_err
= 0;
235 static int sshpam_authenticated
= 0;
236 static int sshpam_session_open
= 0;
237 static int sshpam_cred_established
= 0;
238 static int sshpam_account_status
= -1;
239 static int sshpam_maxtries_reached
= 0;
240 static char **sshpam_env
= NULL
;
241 static Authctxt
*sshpam_authctxt
= NULL
;
242 static const char *sshpam_password
= NULL
;
244 /* Some PAM implementations don't implement this */
245 #ifndef HAVE_PAM_GETENVLIST
247 pam_getenvlist(pam_handle_t
*pamh
)
250 * XXX - If necessary, we can still support envrionment passing
251 * for platforms without pam_getenvlist by searching for known
252 * env vars (e.g. KRB5CCNAME) from the PAM environment.
259 * Some platforms, notably Solaris, do not enforce password complexity
260 * rules during pam_chauthtok() if the real uid of the calling process
261 * is 0, on the assumption that it's being called by "passwd" run by root.
262 * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
265 #ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
267 sshpam_chauthtok_ruid(pam_handle_t
*pamh
, int flags
)
271 if (sshpam_authctxt
== NULL
)
272 fatal("PAM: sshpam_authctxt not initialized");
273 if (setreuid(sshpam_authctxt
->pw
->pw_uid
, -1) == -1)
274 fatal("%s: setreuid failed: %s", __func__
, strerror(errno
));
275 result
= pam_chauthtok(pamh
, flags
);
276 if (setreuid(0, -1) == -1)
277 fatal("%s: setreuid failed: %s", __func__
, strerror(errno
));
280 # define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b)))
284 sshpam_password_change_required(int reqd
)
286 debug3("%s %d", __func__
, reqd
);
287 if (sshpam_authctxt
== NULL
)
288 fatal("%s: PAM authctxt not initialized", __func__
);
289 sshpam_authctxt
->force_pwchange
= reqd
;
291 no_port_forwarding_flag
|= 2;
292 no_agent_forwarding_flag
|= 2;
293 no_x11_forwarding_flag
|= 2;
295 no_port_forwarding_flag
&= ~2;
296 no_agent_forwarding_flag
&= ~2;
297 no_x11_forwarding_flag
&= ~2;
301 /* Import regular and PAM environment from subprocess */
303 import_environments(Buffer
*b
)
309 debug3("PAM: %s entering", __func__
);
311 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
312 /* Import variables set by do_pam_account */
313 sshpam_account_status
= buffer_get_int(b
);
314 sshpam_password_change_required(buffer_get_int(b
));
316 /* Import environment from subprocess */
317 num_env
= buffer_get_int(b
);
319 fatal("%s: received %u environment variables, expected <= 1024",
321 sshpam_env
= xcalloc(num_env
+ 1, sizeof(*sshpam_env
));
322 debug3("PAM: num env strings %d", num_env
);
323 for(i
= 0; i
< num_env
; i
++)
324 sshpam_env
[i
] = buffer_get_string(b
, NULL
);
326 sshpam_env
[num_env
] = NULL
;
328 /* Import PAM environment from subprocess */
329 num_env
= buffer_get_int(b
);
330 debug("PAM: num PAM env strings %d", num_env
);
331 for(i
= 0; i
< num_env
; i
++) {
332 env
= buffer_get_string(b
, NULL
);
334 #ifdef HAVE_PAM_PUTENV
335 /* Errors are not fatal here */
336 if ((err
= pam_putenv(sshpam_handle
, env
)) != PAM_SUCCESS
) {
337 error("PAM: pam_putenv: %s",
338 pam_strerror(sshpam_handle
, sshpam_err
));
346 * Conversation function for authentication thread.
349 sshpam_thread_conv(int n
, sshpam_const
struct pam_message
**msg
,
350 struct pam_response
**resp
, void *data
)
353 struct pam_ctxt
*ctxt
;
354 struct pam_response
*reply
;
357 debug3("PAM: %s entering, %d messages", __func__
, n
);
361 error("PAM: conversation function passed a null context");
362 return (PAM_CONV_ERR
);
365 if (n
<= 0 || n
> PAM_MAX_NUM_MSG
)
366 return (PAM_CONV_ERR
);
368 if ((reply
= calloc(n
, sizeof(*reply
))) == NULL
)
369 return (PAM_CONV_ERR
);
371 buffer_init(&buffer
);
372 for (i
= 0; i
< n
; ++i
) {
373 switch (PAM_MSG_MEMBER(msg
, i
, msg_style
)) {
374 case PAM_PROMPT_ECHO_OFF
:
375 case PAM_PROMPT_ECHO_ON
:
376 buffer_put_cstring(&buffer
,
377 PAM_MSG_MEMBER(msg
, i
, msg
));
378 if (ssh_msg_send(ctxt
->pam_csock
,
379 PAM_MSG_MEMBER(msg
, i
, msg_style
), &buffer
) == -1)
381 if (ssh_msg_recv(ctxt
->pam_csock
, &buffer
) == -1)
383 if (buffer_get_char(&buffer
) != PAM_AUTHTOK
)
385 reply
[i
].resp
= buffer_get_string(&buffer
, NULL
);
389 buffer_put_cstring(&buffer
,
390 PAM_MSG_MEMBER(msg
, i
, msg
));
391 if (ssh_msg_send(ctxt
->pam_csock
,
392 PAM_MSG_MEMBER(msg
, i
, msg_style
), &buffer
) == -1)
398 buffer_clear(&buffer
);
400 buffer_free(&buffer
);
402 return (PAM_SUCCESS
);
405 for(i
= 0; i
< n
; i
++) {
409 buffer_free(&buffer
);
410 return (PAM_CONV_ERR
);
414 * Authentication thread.
417 sshpam_thread(void *ctxtp
)
419 struct pam_ctxt
*ctxt
= ctxtp
;
421 struct pam_conv sshpam_conv
;
422 int flags
= (options
.permit_empty_passwd
== 0 ?
423 PAM_DISALLOW_NULL_AUTHTOK
: 0);
424 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
425 extern char **environ
;
428 const char *pam_user
;
429 const char **ptr_pam_user
= &pam_user
;
430 char *tz
= getenv("TZ");
432 sshpam_err
= pam_get_item(sshpam_handle
, PAM_USER
,
433 (sshpam_const
void **)ptr_pam_user
);
434 if (sshpam_err
!= PAM_SUCCESS
)
439 if (setenv("TZ", tz
, 1) == -1)
440 error("PAM: could not set TZ environment: %s",
443 if (sshpam_authctxt
!= NULL
) {
444 setproctitle("%s [pam]",
445 sshpam_authctxt
->valid
? pam_user
: "unknown");
449 sshpam_conv
.conv
= sshpam_thread_conv
;
450 sshpam_conv
.appdata_ptr
= ctxt
;
452 if (sshpam_authctxt
== NULL
)
453 fatal("%s: PAM authctxt not initialized", __func__
);
455 buffer_init(&buffer
);
456 sshpam_err
= pam_set_item(sshpam_handle
, PAM_CONV
,
457 (const void *)&sshpam_conv
);
458 if (sshpam_err
!= PAM_SUCCESS
)
460 sshpam_err
= pam_authenticate(sshpam_handle
, flags
);
461 if (sshpam_err
== PAM_MAXTRIES
)
462 sshpam_set_maxtries_reached(1);
463 if (sshpam_err
!= PAM_SUCCESS
)
467 if (!do_pam_account()) {
468 sshpam_err
= PAM_ACCT_EXPIRED
;
471 if (sshpam_authctxt
->force_pwchange
) {
472 sshpam_err
= pam_chauthtok(sshpam_handle
,
473 PAM_CHANGE_EXPIRED_AUTHTOK
);
474 if (sshpam_err
!= PAM_SUCCESS
)
476 sshpam_password_change_required(0);
480 buffer_put_cstring(&buffer
, "OK");
482 #ifndef UNSUPPORTED_POSIX_THREADS_HACK
483 /* Export variables set by do_pam_account */
484 buffer_put_int(&buffer
, sshpam_account_status
);
485 buffer_put_int(&buffer
, sshpam_authctxt
->force_pwchange
);
487 /* Export any environment strings set in child */
488 for(i
= 0; environ
[i
] != NULL
; i
++)
490 buffer_put_int(&buffer
, i
);
491 for(i
= 0; environ
[i
] != NULL
; i
++)
492 buffer_put_cstring(&buffer
, environ
[i
]);
494 /* Export any environment strings set by PAM in child */
495 env_from_pam
= pam_getenvlist(sshpam_handle
);
496 for(i
= 0; env_from_pam
!= NULL
&& env_from_pam
[i
] != NULL
; i
++)
498 buffer_put_int(&buffer
, i
);
499 for(i
= 0; env_from_pam
!= NULL
&& env_from_pam
[i
] != NULL
; i
++)
500 buffer_put_cstring(&buffer
, env_from_pam
[i
]);
501 #endif /* UNSUPPORTED_POSIX_THREADS_HACK */
503 /* XXX - can't do much about an error here */
504 ssh_msg_send(ctxt
->pam_csock
, sshpam_err
, &buffer
);
505 buffer_free(&buffer
);
509 buffer_put_cstring(&buffer
,
510 pam_strerror(sshpam_handle
, sshpam_err
));
511 /* XXX - can't do much about an error here */
512 if (sshpam_err
== PAM_ACCT_EXPIRED
)
513 ssh_msg_send(ctxt
->pam_csock
, PAM_ACCT_EXPIRED
, &buffer
);
514 else if (sshpam_maxtries_reached
)
515 ssh_msg_send(ctxt
->pam_csock
, PAM_MAXTRIES
, &buffer
);
517 ssh_msg_send(ctxt
->pam_csock
, PAM_AUTH_ERR
, &buffer
);
518 buffer_free(&buffer
);
521 return (NULL
); /* Avoid warning for non-pthread case */
525 sshpam_thread_cleanup(void)
527 struct pam_ctxt
*ctxt
= cleanup_ctxt
;
529 debug3("PAM: %s entering", __func__
);
530 if (ctxt
!= NULL
&& ctxt
->pam_thread
!= 0) {
531 pthread_cancel(ctxt
->pam_thread
);
532 pthread_join(ctxt
->pam_thread
, NULL
);
533 close(ctxt
->pam_psock
);
534 close(ctxt
->pam_csock
);
535 memset(ctxt
, 0, sizeof(*ctxt
));
541 sshpam_null_conv(int n
, sshpam_const
struct pam_message
**msg
,
542 struct pam_response
**resp
, void *data
)
544 debug3("PAM: %s entering, %d messages", __func__
, n
);
545 return (PAM_CONV_ERR
);
548 static struct pam_conv null_conv
= { sshpam_null_conv
, NULL
};
551 sshpam_store_conv(int n
, sshpam_const
struct pam_message
**msg
,
552 struct pam_response
**resp
, void *data
)
554 struct pam_response
*reply
;
558 debug3("PAM: %s called with %d messages", __func__
, n
);
561 if (n
<= 0 || n
> PAM_MAX_NUM_MSG
)
562 return (PAM_CONV_ERR
);
564 if ((reply
= calloc(n
, sizeof(*reply
))) == NULL
)
565 return (PAM_CONV_ERR
);
567 for (i
= 0; i
< n
; ++i
) {
568 switch (PAM_MSG_MEMBER(msg
, i
, msg_style
)) {
571 len
= strlen(PAM_MSG_MEMBER(msg
, i
, msg
));
572 buffer_append(&loginmsg
, PAM_MSG_MEMBER(msg
, i
, msg
), len
);
573 buffer_append(&loginmsg
, "\n", 1 );
574 reply
[i
].resp_retcode
= PAM_SUCCESS
;
581 return (PAM_SUCCESS
);
584 for(i
= 0; i
< n
; i
++) {
588 return (PAM_CONV_ERR
);
591 static struct pam_conv store_conv
= { sshpam_store_conv
, NULL
};
596 if (sshpam_handle
== NULL
|| (use_privsep
&& !mm_is_monitor()))
598 debug("PAM: cleanup");
599 pam_set_item(sshpam_handle
, PAM_CONV
, (const void *)&null_conv
);
600 if (sshpam_session_open
) {
601 debug("PAM: closing session");
602 pam_close_session(sshpam_handle
, PAM_SILENT
);
603 sshpam_session_open
= 0;
605 if (sshpam_cred_established
) {
606 debug("PAM: deleting credentials");
607 pam_setcred(sshpam_handle
, PAM_DELETE_CRED
);
608 sshpam_cred_established
= 0;
610 sshpam_authenticated
= 0;
611 pam_end(sshpam_handle
, sshpam_err
);
612 sshpam_handle
= NULL
;
616 sshpam_init(Authctxt
*authctxt
)
618 extern char *__progname
;
619 const char *pam_rhost
, *pam_user
, *user
= authctxt
->user
;
620 const char **ptr_pam_user
= &pam_user
;
621 struct ssh
*ssh
= active_state
; /* XXX */
623 if (sshpam_handle
!= NULL
) {
624 /* We already have a PAM context; check if the user matches */
625 sshpam_err
= pam_get_item(sshpam_handle
,
626 PAM_USER
, (sshpam_const
void **)ptr_pam_user
);
627 if (sshpam_err
== PAM_SUCCESS
&& strcmp(user
, pam_user
) == 0)
629 pam_end(sshpam_handle
, sshpam_err
);
630 sshpam_handle
= NULL
;
632 debug("PAM: initializing for \"%s\"", user
);
634 pam_start(SSHD_PAM_SERVICE
, user
, &store_conv
, &sshpam_handle
);
635 sshpam_authctxt
= authctxt
;
637 if (sshpam_err
!= PAM_SUCCESS
) {
638 pam_end(sshpam_handle
, sshpam_err
);
639 sshpam_handle
= NULL
;
642 pam_rhost
= auth_get_canonical_hostname(ssh
, options
.use_dns
);
643 debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost
);
644 sshpam_err
= pam_set_item(sshpam_handle
, PAM_RHOST
, pam_rhost
);
645 if (sshpam_err
!= PAM_SUCCESS
) {
646 pam_end(sshpam_handle
, sshpam_err
);
647 sshpam_handle
= NULL
;
650 #ifdef PAM_TTY_KLUDGE
652 * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
653 * sshd doesn't set the tty until too late in the auth process and
654 * may not even set one (for tty-less connections)
656 debug("PAM: setting PAM_TTY to \"ssh\"");
657 sshpam_err
= pam_set_item(sshpam_handle
, PAM_TTY
, "ssh");
658 if (sshpam_err
!= PAM_SUCCESS
) {
659 pam_end(sshpam_handle
, sshpam_err
);
660 sshpam_handle
= NULL
;
668 sshpam_init_ctx(Authctxt
*authctxt
)
670 struct pam_ctxt
*ctxt
;
673 debug3("PAM: %s entering", __func__
);
675 * Refuse to start if we don't have PAM enabled or do_pam_account
676 * has previously failed.
678 if (!options
.use_pam
|| sshpam_account_status
== 0)
682 if (sshpam_init(authctxt
) == -1) {
683 error("PAM: initialization failed");
687 ctxt
= xcalloc(1, sizeof *ctxt
);
689 /* Start the authentication thread */
690 if (socketpair(AF_UNIX
, SOCK_STREAM
, PF_UNSPEC
, socks
) == -1) {
691 error("PAM: failed create sockets: %s", strerror(errno
));
695 ctxt
->pam_psock
= socks
[0];
696 ctxt
->pam_csock
= socks
[1];
697 if (pthread_create(&ctxt
->pam_thread
, NULL
, sshpam_thread
, ctxt
) == -1) {
698 error("PAM: failed to start authentication thread: %s",
710 sshpam_query(void *ctx
, char **name
, char **info
,
711 u_int
*num
, char ***prompts
, u_int
**echo_on
)
713 struct ssh
*ssh
= active_state
; /* XXX */
715 struct pam_ctxt
*ctxt
= ctx
;
721 debug3("PAM: %s entering", __func__
);
722 buffer_init(&buffer
);
725 *prompts
= xmalloc(sizeof(char *));
728 *echo_on
= xmalloc(sizeof(u_int
));
729 while (ssh_msg_recv(ctxt
->pam_psock
, &buffer
) == 0) {
730 type
= buffer_get_char(&buffer
);
731 msg
= buffer_get_string(&buffer
, NULL
);
734 case PAM_PROMPT_ECHO_ON
:
735 case PAM_PROMPT_ECHO_OFF
:
737 len
= plen
+ mlen
+ 1;
738 **prompts
= xreallocarray(**prompts
, 1, len
);
739 strlcpy(**prompts
+ plen
, msg
, len
- plen
);
741 **echo_on
= (type
== PAM_PROMPT_ECHO_ON
);
746 /* accumulate messages */
747 len
= plen
+ mlen
+ 2;
748 **prompts
= xreallocarray(**prompts
, 1, len
);
749 strlcpy(**prompts
+ plen
, msg
, len
- plen
);
751 strlcat(**prompts
+ plen
, "\n", len
- plen
);
755 case PAM_ACCT_EXPIRED
:
757 if (type
== PAM_ACCT_EXPIRED
)
758 sshpam_account_status
= 0;
759 if (type
== PAM_MAXTRIES
)
760 sshpam_set_maxtries_reached(1);
763 debug3("PAM: %s", pam_strerror(sshpam_handle
, type
));
764 if (**prompts
!= NULL
&& strlen(**prompts
) != 0) {
775 if (**prompts
!= NULL
) {
776 /* drain any accumulated messages */
777 debug("PAM: %s", **prompts
);
778 buffer_append(&loginmsg
, **prompts
,
783 if (type
== PAM_SUCCESS
) {
784 if (!sshpam_authctxt
->valid
||
785 (sshpam_authctxt
->pw
->pw_uid
== 0 &&
786 options
.permit_root_login
!= PERMIT_YES
))
787 fatal("Internal error: PAM auth "
788 "succeeded when it should have "
790 import_environments(&buffer
);
797 error("PAM: %s for %s%.100s from %.100s", msg
,
798 sshpam_authctxt
->valid
? "" : "illegal user ",
799 sshpam_authctxt
->user
,
800 auth_get_canonical_hostname(ssh
, options
.use_dns
));
814 * Returns a junk password of identical length to that the user supplied.
815 * Used to mitigate timing attacks against crypt(3)/PAM stacks that
816 * vary processing time in proportion to password length.
819 fake_password(const char *wire_password
)
821 const char junk
[] = "\b\n\r\177INCORRECT";
823 size_t i
, l
= wire_password
!= NULL
? strlen(wire_password
) : 0;
826 fatal("%s: password length too long: %zu", __func__
, l
);
829 for (i
= 0; i
< l
; i
++)
830 ret
[i
] = junk
[i
% (sizeof(junk
) - 1)];
835 /* XXX - see also comment in auth-chall.c:verify_response */
837 sshpam_respond(void *ctx
, u_int num
, char **resp
)
840 struct pam_ctxt
*ctxt
= ctx
;
843 debug2("PAM: %s entering, %u responses", __func__
, num
);
844 switch (ctxt
->pam_done
) {
846 sshpam_authenticated
= 1;
854 error("PAM: expected one response, got %u", num
);
857 buffer_init(&buffer
);
858 if (sshpam_authctxt
->valid
&&
859 (sshpam_authctxt
->pw
->pw_uid
!= 0 ||
860 options
.permit_root_login
== PERMIT_YES
))
861 buffer_put_cstring(&buffer
, *resp
);
863 fake
= fake_password(*resp
);
864 buffer_put_cstring(&buffer
, fake
);
867 if (ssh_msg_send(ctxt
->pam_psock
, PAM_AUTHTOK
, &buffer
) == -1) {
868 buffer_free(&buffer
);
871 buffer_free(&buffer
);
876 sshpam_free_ctx(void *ctxtp
)
878 struct pam_ctxt
*ctxt
= ctxtp
;
880 debug3("PAM: %s entering", __func__
);
881 sshpam_thread_cleanup();
884 * We don't call sshpam_cleanup() here because we may need the PAM
885 * handle at a later stage, e.g. when setting up a session. It's
886 * still on the cleanup list, so pam_end() *will* be called before
887 * the server process terminates.
891 KbdintDevice sshpam_device
= {
899 KbdintDevice mm_sshpam_device
= {
908 * This replaces auth-pam.c
911 start_pam(Authctxt
*authctxt
)
913 if (!options
.use_pam
)
914 fatal("PAM: initialisation requested when UsePAM=no");
916 if (sshpam_init(authctxt
) == -1)
917 fatal("PAM: initialisation failed");
929 debug("%s: called", __func__
);
930 if (sshpam_account_status
!= -1)
931 return (sshpam_account_status
);
933 sshpam_err
= pam_acct_mgmt(sshpam_handle
, 0);
934 debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__
, sshpam_err
,
935 pam_strerror(sshpam_handle
, sshpam_err
));
937 if (sshpam_err
!= PAM_SUCCESS
&& sshpam_err
!= PAM_NEW_AUTHTOK_REQD
) {
938 sshpam_account_status
= 0;
939 return (sshpam_account_status
);
942 if (sshpam_err
== PAM_NEW_AUTHTOK_REQD
)
943 sshpam_password_change_required(1);
945 sshpam_account_status
= 1;
946 return (sshpam_account_status
);
950 do_pam_set_tty(const char *tty
)
953 debug("PAM: setting PAM_TTY to \"%s\"", tty
);
954 sshpam_err
= pam_set_item(sshpam_handle
, PAM_TTY
, tty
);
955 if (sshpam_err
!= PAM_SUCCESS
)
956 fatal("PAM: failed to set PAM_TTY: %s",
957 pam_strerror(sshpam_handle
, sshpam_err
));
962 do_pam_setcred(int init
)
964 sshpam_err
= pam_set_item(sshpam_handle
, PAM_CONV
,
965 (const void *)&store_conv
);
966 if (sshpam_err
!= PAM_SUCCESS
)
967 fatal("PAM: failed to set PAM_CONV: %s",
968 pam_strerror(sshpam_handle
, sshpam_err
));
970 debug("PAM: establishing credentials");
971 sshpam_err
= pam_setcred(sshpam_handle
, PAM_ESTABLISH_CRED
);
973 debug("PAM: reinitializing credentials");
974 sshpam_err
= pam_setcred(sshpam_handle
, PAM_REINITIALIZE_CRED
);
976 if (sshpam_err
== PAM_SUCCESS
) {
977 sshpam_cred_established
= 1;
980 if (sshpam_authenticated
)
981 fatal("PAM: pam_setcred(): %s",
982 pam_strerror(sshpam_handle
, sshpam_err
));
984 debug("PAM: pam_setcred(): %s",
985 pam_strerror(sshpam_handle
, sshpam_err
));
989 sshpam_tty_conv(int n
, sshpam_const
struct pam_message
**msg
,
990 struct pam_response
**resp
, void *data
)
992 char input
[PAM_MAX_MSG_SIZE
];
993 struct pam_response
*reply
;
996 debug3("PAM: %s called with %d messages", __func__
, n
);
1000 if (n
<= 0 || n
> PAM_MAX_NUM_MSG
|| !isatty(STDIN_FILENO
))
1001 return (PAM_CONV_ERR
);
1003 if ((reply
= calloc(n
, sizeof(*reply
))) == NULL
)
1004 return (PAM_CONV_ERR
);
1006 for (i
= 0; i
< n
; ++i
) {
1007 switch (PAM_MSG_MEMBER(msg
, i
, msg_style
)) {
1008 case PAM_PROMPT_ECHO_OFF
:
1010 read_passphrase(PAM_MSG_MEMBER(msg
, i
, msg
),
1012 reply
[i
].resp_retcode
= PAM_SUCCESS
;
1014 case PAM_PROMPT_ECHO_ON
:
1015 fprintf(stderr
, "%s\n", PAM_MSG_MEMBER(msg
, i
, msg
));
1016 if (fgets(input
, sizeof input
, stdin
) == NULL
)
1018 if ((reply
[i
].resp
= strdup(input
)) == NULL
)
1020 reply
[i
].resp_retcode
= PAM_SUCCESS
;
1024 fprintf(stderr
, "%s\n", PAM_MSG_MEMBER(msg
, i
, msg
));
1025 reply
[i
].resp_retcode
= PAM_SUCCESS
;
1032 return (PAM_SUCCESS
);
1035 for(i
= 0; i
< n
; i
++) {
1036 free(reply
[i
].resp
);
1039 return (PAM_CONV_ERR
);
1042 static struct pam_conv tty_conv
= { sshpam_tty_conv
, NULL
};
1045 * XXX this should be done in the authentication phase, but ssh1 doesn't
1049 do_pam_chauthtok(void)
1052 fatal("Password expired (unable to change with privsep)");
1053 sshpam_err
= pam_set_item(sshpam_handle
, PAM_CONV
,
1054 (const void *)&tty_conv
);
1055 if (sshpam_err
!= PAM_SUCCESS
)
1056 fatal("PAM: failed to set PAM_CONV: %s",
1057 pam_strerror(sshpam_handle
, sshpam_err
));
1058 debug("PAM: changing password");
1059 sshpam_err
= pam_chauthtok(sshpam_handle
, PAM_CHANGE_EXPIRED_AUTHTOK
);
1060 if (sshpam_err
!= PAM_SUCCESS
)
1061 fatal("PAM: pam_chauthtok(): %s",
1062 pam_strerror(sshpam_handle
, sshpam_err
));
1066 do_pam_session(void)
1068 debug3("PAM: opening session");
1069 sshpam_err
= pam_set_item(sshpam_handle
, PAM_CONV
,
1070 (const void *)&store_conv
);
1071 if (sshpam_err
!= PAM_SUCCESS
)
1072 fatal("PAM: failed to set PAM_CONV: %s",
1073 pam_strerror(sshpam_handle
, sshpam_err
));
1074 sshpam_err
= pam_open_session(sshpam_handle
, 0);
1075 if (sshpam_err
== PAM_SUCCESS
)
1076 sshpam_session_open
= 1;
1078 sshpam_session_open
= 0;
1079 disable_forwarding();
1080 error("PAM: pam_open_session(): %s",
1081 pam_strerror(sshpam_handle
, sshpam_err
));
1087 is_pam_session_open(void)
1089 return sshpam_session_open
;
1093 * Set a PAM environment string. We need to do this so that the session
1094 * modules can handle things like Kerberos/GSI credentials that appear
1095 * during the ssh authentication process.
1098 do_pam_putenv(char *name
, char *value
)
1101 #ifdef HAVE_PAM_PUTENV
1105 len
= strlen(name
) + strlen(value
) + 2;
1106 compound
= xmalloc(len
);
1108 snprintf(compound
, len
, "%s=%s", name
, value
);
1109 ret
= pam_putenv(sshpam_handle
, compound
);
1117 fetch_pam_child_environment(void)
1123 fetch_pam_environment(void)
1125 return (pam_getenvlist(sshpam_handle
));
1129 free_pam_environment(char **env
)
1136 for (envp
= env
; *envp
; envp
++)
1142 * "Blind" conversation function for password authentication. Assumes that
1143 * echo-off prompts are for the password and stores messages for later
1147 sshpam_passwd_conv(int n
, sshpam_const
struct pam_message
**msg
,
1148 struct pam_response
**resp
, void *data
)
1150 struct pam_response
*reply
;
1154 debug3("PAM: %s called with %d messages", __func__
, n
);
1158 if (n
<= 0 || n
> PAM_MAX_NUM_MSG
)
1159 return (PAM_CONV_ERR
);
1161 if ((reply
= calloc(n
, sizeof(*reply
))) == NULL
)
1162 return (PAM_CONV_ERR
);
1164 for (i
= 0; i
< n
; ++i
) {
1165 switch (PAM_MSG_MEMBER(msg
, i
, msg_style
)) {
1166 case PAM_PROMPT_ECHO_OFF
:
1167 if (sshpam_password
== NULL
)
1169 if ((reply
[i
].resp
= strdup(sshpam_password
)) == NULL
)
1171 reply
[i
].resp_retcode
= PAM_SUCCESS
;
1175 len
= strlen(PAM_MSG_MEMBER(msg
, i
, msg
));
1177 buffer_append(&loginmsg
,
1178 PAM_MSG_MEMBER(msg
, i
, msg
), len
);
1179 buffer_append(&loginmsg
, "\n", 1);
1181 if ((reply
[i
].resp
= strdup("")) == NULL
)
1183 reply
[i
].resp_retcode
= PAM_SUCCESS
;
1190 return (PAM_SUCCESS
);
1193 for(i
= 0; i
< n
; i
++) {
1194 free(reply
[i
].resp
);
1197 return (PAM_CONV_ERR
);
1200 static struct pam_conv passwd_conv
= { sshpam_passwd_conv
, NULL
};
1203 * Attempt password authentication via PAM
1206 sshpam_auth_passwd(Authctxt
*authctxt
, const char *password
)
1208 int flags
= (options
.permit_empty_passwd
== 0 ?
1209 PAM_DISALLOW_NULL_AUTHTOK
: 0);
1212 if (!options
.use_pam
|| sshpam_handle
== NULL
)
1213 fatal("PAM: %s called when PAM disabled or failed to "
1214 "initialise.", __func__
);
1216 sshpam_password
= password
;
1217 sshpam_authctxt
= authctxt
;
1220 * If the user logging in is invalid, or is root but is not permitted
1221 * by PermitRootLogin, use an invalid password to prevent leaking
1222 * information via timing (eg if the PAM config has a delay on fail).
1224 if (!authctxt
->valid
|| (authctxt
->pw
->pw_uid
== 0 &&
1225 options
.permit_root_login
!= PERMIT_YES
))
1226 sshpam_password
= fake
= fake_password(password
);
1228 sshpam_err
= pam_set_item(sshpam_handle
, PAM_CONV
,
1229 (const void *)&passwd_conv
);
1230 if (sshpam_err
!= PAM_SUCCESS
)
1231 fatal("PAM: %s: failed to set PAM_CONV: %s", __func__
,
1232 pam_strerror(sshpam_handle
, sshpam_err
));
1234 sshpam_err
= pam_authenticate(sshpam_handle
, flags
);
1235 sshpam_password
= NULL
;
1237 if (sshpam_err
== PAM_MAXTRIES
)
1238 sshpam_set_maxtries_reached(1);
1239 if (sshpam_err
== PAM_SUCCESS
&& authctxt
->valid
) {
1240 debug("PAM: password authentication accepted for %.100s",
1244 debug("PAM: password authentication failed for %.100s: %s",
1245 authctxt
->valid
? authctxt
->user
: "an illegal user",
1246 pam_strerror(sshpam_handle
, sshpam_err
));
1252 sshpam_get_maxtries_reached(void)
1254 return sshpam_maxtries_reached
;
1258 sshpam_set_maxtries_reached(int reached
)
1260 if (reached
== 0 || sshpam_maxtries_reached
)
1262 sshpam_maxtries_reached
= 1;
1263 options
.password_authentication
= 0;
1264 options
.kbd_interactive_authentication
= 0;
1265 options
.challenge_response_authentication
= 0;
1267 #endif /* USE_PAM */