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- djm@cvs.openbsd.org 2004/12/22 02:13:19
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1/*-
2 * Copyright (c) 2002 Networks Associates Technology, Inc.
3 * All rights reserved.
4 *
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.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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.
18 *
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
29 * SUCH DAMAGE.
30 */
31/*
32 * Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
33 * Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
34 *
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.
38 *
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.
46 */
47
48/* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
49#include "includes.h"
50RCSID("$Id$");
51
52#ifdef USE_PAM
53#if defined(HAVE_SECURITY_PAM_APPL_H)
54#include <security/pam_appl.h>
55#elif defined (HAVE_PAM_PAM_APPL_H)
56#include <pam/pam_appl.h>
57#endif
58
59#include "auth.h"
60#include "auth-pam.h"
61#include "buffer.h"
62#include "bufaux.h"
63#include "canohost.h"
64#include "log.h"
65#include "monitor_wrap.h"
66#include "msg.h"
67#include "packet.h"
68#include "misc.h"
69#include "servconf.h"
70#include "ssh2.h"
71#include "xmalloc.h"
72#include "auth-options.h"
73
74extern ServerOptions options;
75extern Buffer loginmsg;
76extern int compat20;
77extern u_int utmp_len;
78
79#ifdef USE_POSIX_THREADS
80#include <pthread.h>
81/*
82 * Avoid namespace clash when *not* using pthreads for systems *with*
83 * pthreads, which unconditionally define pthread_t via sys/types.h
84 * (e.g. Linux)
85 */
86typedef pthread_t sp_pthread_t;
87#else
88typedef pid_t sp_pthread_t;
89#endif
90
91struct pam_ctxt {
92 sp_pthread_t pam_thread;
93 int pam_psock;
94 int pam_csock;
95 int pam_done;
96};
97
98static void sshpam_free_ctx(void *);
99static struct pam_ctxt *cleanup_ctxt;
100
101#ifndef USE_POSIX_THREADS
102/*
103 * Simulate threads with processes.
104 */
105
106static int sshpam_thread_status = -1;
107static mysig_t sshpam_oldsig;
108
109static void
110sshpam_sigchld_handler(int sig)
111{
112 signal(SIGCHLD, SIG_DFL);
113 if (cleanup_ctxt == NULL)
114 return; /* handler called after PAM cleanup, shouldn't happen */
115 if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
116 <= 0) {
117 /* PAM thread has not exitted, privsep slave must have */
118 kill(cleanup_ctxt->pam_thread, SIGTERM);
119 if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0)
120 <= 0)
121 return; /* could not wait */
122 }
123 if (WIFSIGNALED(sshpam_thread_status) &&
124 WTERMSIG(sshpam_thread_status) == SIGTERM)
125 return; /* terminated by pthread_cancel */
126 if (!WIFEXITED(sshpam_thread_status))
127 fatal("PAM: authentication thread exited unexpectedly");
128 if (WEXITSTATUS(sshpam_thread_status) != 0)
129 fatal("PAM: authentication thread exited uncleanly");
130}
131
132static void
133pthread_exit(void *value __unused)
134{
135 _exit(0);
136}
137
138static int
139pthread_create(sp_pthread_t *thread, const void *attr __unused,
140 void *(*thread_start)(void *), void *arg)
141{
142 pid_t pid;
143
144 sshpam_thread_status = -1;
145 switch ((pid = fork())) {
146 case -1:
147 error("fork(): %s", strerror(errno));
148 return (-1);
149 case 0:
150 thread_start(arg);
151 _exit(1);
152 default:
153 *thread = pid;
154 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
155 return (0);
156 }
157}
158
159static int
160pthread_cancel(sp_pthread_t thread)
161{
162 signal(SIGCHLD, sshpam_oldsig);
163 return (kill(thread, SIGTERM));
164}
165
166static int
167pthread_join(sp_pthread_t thread, void **value __unused)
168{
169 int status;
170
171 if (sshpam_thread_status != -1)
172 return (sshpam_thread_status);
173 signal(SIGCHLD, sshpam_oldsig);
174 waitpid(thread, &status, 0);
175 return (status);
176}
177#endif
178
179
180static pam_handle_t *sshpam_handle = NULL;
181static int sshpam_err = 0;
182static int sshpam_authenticated = 0;
183static int sshpam_session_open = 0;
184static int sshpam_cred_established = 0;
185static int sshpam_account_status = -1;
186static char **sshpam_env = NULL;
187static Authctxt *sshpam_authctxt = NULL;
188static const char *sshpam_password = NULL;
189static char badpw[] = "\b\n\r\177INCORRECT";
190
191/* Some PAM implementations don't implement this */
192#ifndef HAVE_PAM_GETENVLIST
193static char **
194pam_getenvlist(pam_handle_t *pamh)
195{
196 /*
197 * XXX - If necessary, we can still support envrionment passing
198 * for platforms without pam_getenvlist by searching for known
199 * env vars (e.g. KRB5CCNAME) from the PAM environment.
200 */
201 return NULL;
202}
203#endif
204
205/*
206 * Some platforms, notably Solaris, do not enforce password complexity
207 * rules during pam_chauthtok() if the real uid of the calling process
208 * is 0, on the assumption that it's being called by "passwd" run by root.
209 * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
210 * the right thing.
211 */
212#ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
213static int
214sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
215{
216 int result;
217
218 if (sshpam_authctxt == NULL)
219 fatal("PAM: sshpam_authctxt not initialized");
220 if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
221 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
222 result = pam_chauthtok(pamh, flags);
223 if (setreuid(0, -1) == -1)
224 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
225 return result;
226}
227# define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b)))
228#endif
229
230void
231sshpam_password_change_required(int reqd)
232{
233 debug3("%s %d", __func__, reqd);
234 if (sshpam_authctxt == NULL)
235 fatal("%s: PAM authctxt not initialized", __func__);
236 sshpam_authctxt->force_pwchange = reqd;
237 if (reqd) {
238 no_port_forwarding_flag |= 2;
239 no_agent_forwarding_flag |= 2;
240 no_x11_forwarding_flag |= 2;
241 } else {
242 no_port_forwarding_flag &= ~2;
243 no_agent_forwarding_flag &= ~2;
244 no_x11_forwarding_flag &= ~2;
245 }
246}
247
248/* Check ssh internal flags in addition to PAM */
249
250static int
251sshpam_login_allowed(Authctxt *ctxt)
252{
253 if (ctxt->valid && (ctxt->pw->pw_uid != 0 ||
254 options.permit_root_login == PERMIT_YES))
255 return 1;
256 return 0;
257}
258
259/* Import regular and PAM environment from subprocess */
260static void
261import_environments(Buffer *b)
262{
263 char *env;
264 u_int i, num_env;
265 int err;
266
267 debug3("PAM: %s entering", __func__);
268
269#ifndef USE_POSIX_THREADS
270 /* Import variables set by do_pam_account */
271 sshpam_account_status = buffer_get_int(b);
272 sshpam_password_change_required(buffer_get_int(b));
273
274 /* Import environment from subprocess */
275 num_env = buffer_get_int(b);
276 sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
277 debug3("PAM: num env strings %d", num_env);
278 for(i = 0; i < num_env; i++)
279 sshpam_env[i] = buffer_get_string(b, NULL);
280
281 sshpam_env[num_env] = NULL;
282
283 /* Import PAM environment from subprocess */
284 num_env = buffer_get_int(b);
285 debug("PAM: num PAM env strings %d", num_env);
286 for(i = 0; i < num_env; i++) {
287 env = buffer_get_string(b, NULL);
288
289#ifdef HAVE_PAM_PUTENV
290 /* Errors are not fatal here */
291 if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
292 error("PAM: pam_putenv: %s",
293 pam_strerror(sshpam_handle, sshpam_err));
294 }
295#endif
296 }
297#endif
298}
299
300/*
301 * Conversation function for authentication thread.
302 */
303static int
304sshpam_thread_conv(int n, struct pam_message **msg,
305 struct pam_response **resp, void *data)
306{
307 Buffer buffer;
308 struct pam_ctxt *ctxt;
309 struct pam_response *reply;
310 int i;
311
312 debug3("PAM: %s entering, %d messages", __func__, n);
313 *resp = NULL;
314
315 if (data == NULL) {
316 error("PAM: conversation function passed a null context");
317 return (PAM_CONV_ERR);
318 }
319 ctxt = data;
320 if (n <= 0 || n > PAM_MAX_NUM_MSG)
321 return (PAM_CONV_ERR);
322
323 if ((reply = malloc(n * sizeof(*reply))) == NULL)
324 return (PAM_CONV_ERR);
325 memset(reply, 0, n * sizeof(*reply));
326
327 buffer_init(&buffer);
328 for (i = 0; i < n; ++i) {
329 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
330 case PAM_PROMPT_ECHO_OFF:
331 buffer_put_cstring(&buffer,
332 PAM_MSG_MEMBER(msg, i, msg));
333 if (ssh_msg_send(ctxt->pam_csock,
334 PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
335 goto fail;
336 if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
337 goto fail;
338 if (buffer_get_char(&buffer) != PAM_AUTHTOK)
339 goto fail;
340 reply[i].resp = buffer_get_string(&buffer, NULL);
341 break;
342 case PAM_PROMPT_ECHO_ON:
343 buffer_put_cstring(&buffer,
344 PAM_MSG_MEMBER(msg, i, msg));
345 if (ssh_msg_send(ctxt->pam_csock,
346 PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
347 goto fail;
348 if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1)
349 goto fail;
350 if (buffer_get_char(&buffer) != PAM_AUTHTOK)
351 goto fail;
352 reply[i].resp = buffer_get_string(&buffer, NULL);
353 break;
354 case PAM_ERROR_MSG:
355 buffer_put_cstring(&buffer,
356 PAM_MSG_MEMBER(msg, i, msg));
357 if (ssh_msg_send(ctxt->pam_csock,
358 PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
359 goto fail;
360 break;
361 case PAM_TEXT_INFO:
362 buffer_put_cstring(&buffer,
363 PAM_MSG_MEMBER(msg, i, msg));
364 if (ssh_msg_send(ctxt->pam_csock,
365 PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1)
366 goto fail;
367 break;
368 default:
369 goto fail;
370 }
371 buffer_clear(&buffer);
372 }
373 buffer_free(&buffer);
374 *resp = reply;
375 return (PAM_SUCCESS);
376
377 fail:
378 for(i = 0; i < n; i++) {
379 if (reply[i].resp != NULL)
380 xfree(reply[i].resp);
381 }
382 xfree(reply);
383 buffer_free(&buffer);
384 return (PAM_CONV_ERR);
385}
386
387/*
388 * Authentication thread.
389 */
390static void *
391sshpam_thread(void *ctxtp)
392{
393 struct pam_ctxt *ctxt = ctxtp;
394 Buffer buffer;
395 struct pam_conv sshpam_conv;
396 int flags = (options.permit_empty_passwd == 0 ?
397 PAM_DISALLOW_NULL_AUTHTOK : 0);
398#ifndef USE_POSIX_THREADS
399 extern char **environ;
400 char **env_from_pam;
401 u_int i;
402 const char *pam_user;
403
404 pam_get_item(sshpam_handle, PAM_USER, (void **)&pam_user);
405 environ[0] = NULL;
406
407 if (sshpam_authctxt != NULL) {
408 setproctitle("%s [pam]",
409 sshpam_authctxt->valid ? pam_user : "unknown");
410 }
411#endif
412
413 sshpam_conv.conv = sshpam_thread_conv;
414 sshpam_conv.appdata_ptr = ctxt;
415
416 if (sshpam_authctxt == NULL)
417 fatal("%s: PAM authctxt not initialized", __func__);
418
419 buffer_init(&buffer);
420 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
421 (const void *)&sshpam_conv);
422 if (sshpam_err != PAM_SUCCESS)
423 goto auth_fail;
424 sshpam_err = pam_authenticate(sshpam_handle, flags);
425 if (sshpam_err != PAM_SUCCESS)
426 goto auth_fail;
427
428 if (compat20) {
429 if (!do_pam_account())
430 goto auth_fail;
431 if (sshpam_authctxt->force_pwchange) {
432 sshpam_err = pam_chauthtok(sshpam_handle,
433 PAM_CHANGE_EXPIRED_AUTHTOK);
434 if (sshpam_err != PAM_SUCCESS)
435 goto auth_fail;
436 sshpam_password_change_required(0);
437 }
438 }
439
440 buffer_put_cstring(&buffer, "OK");
441
442#ifndef USE_POSIX_THREADS
443 /* Export variables set by do_pam_account */
444 buffer_put_int(&buffer, sshpam_account_status);
445 buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
446
447 /* Export any environment strings set in child */
448 for(i = 0; environ[i] != NULL; i++)
449 ; /* Count */
450 buffer_put_int(&buffer, i);
451 for(i = 0; environ[i] != NULL; i++)
452 buffer_put_cstring(&buffer, environ[i]);
453
454 /* Export any environment strings set by PAM in child */
455 env_from_pam = pam_getenvlist(sshpam_handle);
456 for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
457 ; /* Count */
458 buffer_put_int(&buffer, i);
459 for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
460 buffer_put_cstring(&buffer, env_from_pam[i]);
461#endif /* USE_POSIX_THREADS */
462
463 /* XXX - can't do much about an error here */
464 ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
465 buffer_free(&buffer);
466 pthread_exit(NULL);
467
468 auth_fail:
469 buffer_put_cstring(&buffer,
470 pam_strerror(sshpam_handle, sshpam_err));
471 /* XXX - can't do much about an error here */
472 ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
473 buffer_free(&buffer);
474 pthread_exit(NULL);
475
476 return (NULL); /* Avoid warning for non-pthread case */
477}
478
479void
480sshpam_thread_cleanup(void)
481{
482 struct pam_ctxt *ctxt = cleanup_ctxt;
483
484 debug3("PAM: %s entering", __func__);
485 if (ctxt != NULL && ctxt->pam_thread != 0) {
486 pthread_cancel(ctxt->pam_thread);
487 pthread_join(ctxt->pam_thread, NULL);
488 close(ctxt->pam_psock);
489 close(ctxt->pam_csock);
490 memset(ctxt, 0, sizeof(*ctxt));
491 cleanup_ctxt = NULL;
492 }
493}
494
495static int
496sshpam_null_conv(int n, struct pam_message **msg,
497 struct pam_response **resp, void *data)
498{
499 debug3("PAM: %s entering, %d messages", __func__, n);
500 return (PAM_CONV_ERR);
501}
502
503static struct pam_conv null_conv = { sshpam_null_conv, NULL };
504
505static int
506sshpam_store_conv(int n, struct pam_message **msg,
507 struct pam_response **resp, void *data)
508{
509 struct pam_response *reply;
510 int i;
511 size_t len;
512
513 debug3("PAM: %s called with %d messages", __func__, n);
514 *resp = NULL;
515
516 if (n <= 0 || n > PAM_MAX_NUM_MSG)
517 return (PAM_CONV_ERR);
518
519 if ((reply = malloc(n * sizeof(*reply))) == NULL)
520 return (PAM_CONV_ERR);
521 memset(reply, 0, n * sizeof(*reply));
522
523 for (i = 0; i < n; ++i) {
524 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
525 case PAM_ERROR_MSG:
526 case PAM_TEXT_INFO:
527 len = strlen(PAM_MSG_MEMBER(msg, i, msg));
528 buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
529 buffer_append(&loginmsg, "\n", 1 );
530 reply[i].resp_retcode = PAM_SUCCESS;
531 break;
532 default:
533 goto fail;
534 }
535 }
536 *resp = reply;
537 return (PAM_SUCCESS);
538
539 fail:
540 for(i = 0; i < n; i++) {
541 if (reply[i].resp != NULL)
542 xfree(reply[i].resp);
543 }
544 xfree(reply);
545 return (PAM_CONV_ERR);
546}
547
548static struct pam_conv store_conv = { sshpam_store_conv, NULL };
549
550void
551sshpam_cleanup(void)
552{
553 debug("PAM: cleanup");
554 if (sshpam_handle == NULL)
555 return;
556 pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
557 if (sshpam_cred_established) {
558 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
559 sshpam_cred_established = 0;
560 }
561 if (sshpam_session_open) {
562 pam_close_session(sshpam_handle, PAM_SILENT);
563 sshpam_session_open = 0;
564 }
565 sshpam_authenticated = 0;
566 pam_end(sshpam_handle, sshpam_err);
567 sshpam_handle = NULL;
568}
569
570static int
571sshpam_init(Authctxt *authctxt)
572{
573 extern char *__progname;
574 const char *pam_rhost, *pam_user, *user = authctxt->user;
575
576 if (sshpam_handle != NULL) {
577 /* We already have a PAM context; check if the user matches */
578 sshpam_err = pam_get_item(sshpam_handle,
579 PAM_USER, (void **)&pam_user);
580 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
581 return (0);
582 pam_end(sshpam_handle, sshpam_err);
583 sshpam_handle = NULL;
584 }
585 debug("PAM: initializing for \"%s\"", user);
586 sshpam_err =
587 pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
588 sshpam_authctxt = authctxt;
589
590 if (sshpam_err != PAM_SUCCESS) {
591 pam_end(sshpam_handle, sshpam_err);
592 sshpam_handle = NULL;
593 return (-1);
594 }
595 pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
596 debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
597 sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
598 if (sshpam_err != PAM_SUCCESS) {
599 pam_end(sshpam_handle, sshpam_err);
600 sshpam_handle = NULL;
601 return (-1);
602 }
603#ifdef PAM_TTY_KLUDGE
604 /*
605 * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
606 * sshd doesn't set the tty until too late in the auth process and
607 * may not even set one (for tty-less connections)
608 */
609 debug("PAM: setting PAM_TTY to \"ssh\"");
610 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
611 if (sshpam_err != PAM_SUCCESS) {
612 pam_end(sshpam_handle, sshpam_err);
613 sshpam_handle = NULL;
614 return (-1);
615 }
616#endif
617 return (0);
618}
619
620static void *
621sshpam_init_ctx(Authctxt *authctxt)
622{
623 struct pam_ctxt *ctxt;
624 int socks[2];
625
626 debug3("PAM: %s entering", __func__);
627 /* Refuse to start if we don't have PAM enabled */
628 if (!options.use_pam)
629 return NULL;
630
631 /* Initialize PAM */
632 if (sshpam_init(authctxt) == -1) {
633 error("PAM: initialization failed");
634 return (NULL);
635 }
636
637 ctxt = xmalloc(sizeof *ctxt);
638 memset(ctxt, 0, sizeof(*ctxt));
639
640 /* Start the authentication thread */
641 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
642 error("PAM: failed create sockets: %s", strerror(errno));
643 xfree(ctxt);
644 return (NULL);
645 }
646 ctxt->pam_psock = socks[0];
647 ctxt->pam_csock = socks[1];
648 if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
649 error("PAM: failed to start authentication thread: %s",
650 strerror(errno));
651 close(socks[0]);
652 close(socks[1]);
653 xfree(ctxt);
654 return (NULL);
655 }
656 cleanup_ctxt = ctxt;
657 return (ctxt);
658}
659
660static int
661sshpam_query(void *ctx, char **name, char **info,
662 u_int *num, char ***prompts, u_int **echo_on)
663{
664 Buffer buffer;
665 struct pam_ctxt *ctxt = ctx;
666 size_t plen;
667 u_char type;
668 char *msg;
669 size_t len, mlen;
670
671 debug3("PAM: %s entering", __func__);
672 buffer_init(&buffer);
673 *name = xstrdup("");
674 *info = xstrdup("");
675 *prompts = xmalloc(sizeof(char *));
676 **prompts = NULL;
677 plen = 0;
678 *echo_on = xmalloc(sizeof(u_int));
679 while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
680 type = buffer_get_char(&buffer);
681 msg = buffer_get_string(&buffer, NULL);
682 mlen = strlen(msg);
683 switch (type) {
684 case PAM_PROMPT_ECHO_ON:
685 case PAM_PROMPT_ECHO_OFF:
686 *num = 1;
687 len = plen + mlen + 1;
688 **prompts = xrealloc(**prompts, len);
689 strlcpy(**prompts + plen, msg, len - plen);
690 plen += mlen;
691 **echo_on = (type == PAM_PROMPT_ECHO_ON);
692 xfree(msg);
693 return (0);
694 case PAM_ERROR_MSG:
695 case PAM_TEXT_INFO:
696 /* accumulate messages */
697 len = plen + mlen + 2;
698 **prompts = xrealloc(**prompts, len);
699 strlcpy(**prompts + plen, msg, len - plen);
700 plen += mlen;
701 strlcat(**prompts + plen, "\n", len - plen);
702 plen++;
703 xfree(msg);
704 break;
705 case PAM_SUCCESS:
706 case PAM_AUTH_ERR:
707 if (**prompts != NULL) {
708 /* drain any accumulated messages */
709 debug("PAM: %s", **prompts);
710 buffer_append(&loginmsg, **prompts,
711 strlen(**prompts));
712 xfree(**prompts);
713 **prompts = NULL;
714 }
715 if (type == PAM_SUCCESS) {
716 if (!sshpam_login_allowed(sshpam_authctxt))
717 fatal("Internal error: PAM auth "
718 "succeeded when it should have "
719 "failed");
720 import_environments(&buffer);
721 *num = 0;
722 **echo_on = 0;
723 ctxt->pam_done = 1;
724 xfree(msg);
725 return (0);
726 }
727 error("PAM: %s for %s%.100s from %.100s", msg,
728 sshpam_authctxt->valid ? "" : "illegal user ",
729 sshpam_authctxt->user,
730 get_remote_name_or_ip(utmp_len, options.use_dns));
731 /* FALLTHROUGH */
732 default:
733 *num = 0;
734 **echo_on = 0;
735 xfree(msg);
736 ctxt->pam_done = -1;
737 return (-1);
738 }
739 }
740 return (-1);
741}
742
743/* XXX - see also comment in auth-chall.c:verify_response */
744static int
745sshpam_respond(void *ctx, u_int num, char **resp)
746{
747 Buffer buffer;
748 struct pam_ctxt *ctxt = ctx;
749
750 debug2("PAM: %s entering, %d responses", __func__, num);
751 switch (ctxt->pam_done) {
752 case 1:
753 sshpam_authenticated = 1;
754 return (0);
755 case 0:
756 break;
757 default:
758 return (-1);
759 }
760 if (num != 1) {
761 error("PAM: expected one response, got %u", num);
762 return (-1);
763 }
764 buffer_init(&buffer);
765 if (sshpam_login_allowed(sshpam_authctxt))
766 buffer_put_cstring(&buffer, *resp);
767 else
768 buffer_put_cstring(&buffer, badpw);
769 if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
770 buffer_free(&buffer);
771 return (-1);
772 }
773 buffer_free(&buffer);
774 return (1);
775}
776
777static void
778sshpam_free_ctx(void *ctxtp)
779{
780 struct pam_ctxt *ctxt = ctxtp;
781
782 debug3("PAM: %s entering", __func__);
783 sshpam_thread_cleanup();
784 xfree(ctxt);
785 /*
786 * We don't call sshpam_cleanup() here because we may need the PAM
787 * handle at a later stage, e.g. when setting up a session. It's
788 * still on the cleanup list, so pam_end() *will* be called before
789 * the server process terminates.
790 */
791}
792
793KbdintDevice sshpam_device = {
794 "pam",
795 sshpam_init_ctx,
796 sshpam_query,
797 sshpam_respond,
798 sshpam_free_ctx
799};
800
801KbdintDevice mm_sshpam_device = {
802 "pam",
803 mm_sshpam_init_ctx,
804 mm_sshpam_query,
805 mm_sshpam_respond,
806 mm_sshpam_free_ctx
807};
808
809/*
810 * This replaces auth-pam.c
811 */
812void
813start_pam(Authctxt *authctxt)
814{
815 if (!options.use_pam)
816 fatal("PAM: initialisation requested when UsePAM=no");
817
818 if (sshpam_init(authctxt) == -1)
819 fatal("PAM: initialisation failed");
820}
821
822void
823finish_pam(void)
824{
825 sshpam_cleanup();
826}
827
828u_int
829do_pam_account(void)
830{
831 debug("%s: called", __func__);
832 if (sshpam_account_status != -1)
833 return (sshpam_account_status);
834
835 sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
836 debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
837 pam_strerror(sshpam_handle, sshpam_err));
838
839 if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
840 sshpam_account_status = 0;
841 return (sshpam_account_status);
842 }
843
844 if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
845 sshpam_password_change_required(1);
846
847 sshpam_account_status = 1;
848 return (sshpam_account_status);
849}
850
851void
852do_pam_set_tty(const char *tty)
853{
854 if (tty != NULL) {
855 debug("PAM: setting PAM_TTY to \"%s\"", tty);
856 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
857 if (sshpam_err != PAM_SUCCESS)
858 fatal("PAM: failed to set PAM_TTY: %s",
859 pam_strerror(sshpam_handle, sshpam_err));
860 }
861}
862
863void
864do_pam_setcred(int init)
865{
866 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
867 (const void *)&store_conv);
868 if (sshpam_err != PAM_SUCCESS)
869 fatal("PAM: failed to set PAM_CONV: %s",
870 pam_strerror(sshpam_handle, sshpam_err));
871 if (init) {
872 debug("PAM: establishing credentials");
873 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
874 } else {
875 debug("PAM: reinitializing credentials");
876 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
877 }
878 if (sshpam_err == PAM_SUCCESS) {
879 sshpam_cred_established = 1;
880 return;
881 }
882 if (sshpam_authenticated)
883 fatal("PAM: pam_setcred(): %s",
884 pam_strerror(sshpam_handle, sshpam_err));
885 else
886 debug("PAM: pam_setcred(): %s",
887 pam_strerror(sshpam_handle, sshpam_err));
888}
889
890static int
891sshpam_tty_conv(int n, struct pam_message **msg,
892 struct pam_response **resp, void *data)
893{
894 char input[PAM_MAX_MSG_SIZE];
895 struct pam_response *reply;
896 int i;
897
898 debug3("PAM: %s called with %d messages", __func__, n);
899
900 *resp = NULL;
901
902 if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
903 return (PAM_CONV_ERR);
904
905 if ((reply = malloc(n * sizeof(*reply))) == NULL)
906 return (PAM_CONV_ERR);
907 memset(reply, 0, n * sizeof(*reply));
908
909 for (i = 0; i < n; ++i) {
910 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
911 case PAM_PROMPT_ECHO_OFF:
912 reply[i].resp =
913 read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
914 RP_ALLOW_STDIN);
915 reply[i].resp_retcode = PAM_SUCCESS;
916 break;
917 case PAM_PROMPT_ECHO_ON:
918 fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
919 fgets(input, sizeof input, stdin);
920 if ((reply[i].resp = strdup(input)) == NULL)
921 goto fail;
922 reply[i].resp_retcode = PAM_SUCCESS;
923 break;
924 case PAM_ERROR_MSG:
925 case PAM_TEXT_INFO:
926 fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
927 reply[i].resp_retcode = PAM_SUCCESS;
928 break;
929 default:
930 goto fail;
931 }
932 }
933 *resp = reply;
934 return (PAM_SUCCESS);
935
936 fail:
937 for(i = 0; i < n; i++) {
938 if (reply[i].resp != NULL)
939 xfree(reply[i].resp);
940 }
941 xfree(reply);
942 return (PAM_CONV_ERR);
943}
944
945static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
946
947/*
948 * XXX this should be done in the authentication phase, but ssh1 doesn't
949 * support that
950 */
951void
952do_pam_chauthtok(void)
953{
954 if (use_privsep)
955 fatal("Password expired (unable to change with privsep)");
956 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
957 (const void *)&tty_conv);
958 if (sshpam_err != PAM_SUCCESS)
959 fatal("PAM: failed to set PAM_CONV: %s",
960 pam_strerror(sshpam_handle, sshpam_err));
961 debug("PAM: changing password");
962 sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
963 if (sshpam_err != PAM_SUCCESS)
964 fatal("PAM: pam_chauthtok(): %s",
965 pam_strerror(sshpam_handle, sshpam_err));
966}
967
968void
969do_pam_session(void)
970{
971 debug3("PAM: opening session");
972 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
973 (const void *)&store_conv);
974 if (sshpam_err != PAM_SUCCESS)
975 fatal("PAM: failed to set PAM_CONV: %s",
976 pam_strerror(sshpam_handle, sshpam_err));
977 sshpam_err = pam_open_session(sshpam_handle, 0);
978 if (sshpam_err == PAM_SUCCESS)
979 sshpam_session_open = 1;
980 else {
981 sshpam_session_open = 0;
982 disable_forwarding();
983 error("PAM: pam_open_session(): %s",
984 pam_strerror(sshpam_handle, sshpam_err));
985 }
986
987}
988
989int
990is_pam_session_open(void)
991{
992 return sshpam_session_open;
993}
994
995/*
996 * Set a PAM environment string. We need to do this so that the session
997 * modules can handle things like Kerberos/GSI credentials that appear
998 * during the ssh authentication process.
999 */
1000int
1001do_pam_putenv(char *name, char *value)
1002{
1003 int ret = 1;
1004#ifdef HAVE_PAM_PUTENV
1005 char *compound;
1006 size_t len;
1007
1008 len = strlen(name) + strlen(value) + 2;
1009 compound = xmalloc(len);
1010
1011 snprintf(compound, len, "%s=%s", name, value);
1012 ret = pam_putenv(sshpam_handle, compound);
1013 xfree(compound);
1014#endif
1015
1016 return (ret);
1017}
1018
1019char **
1020fetch_pam_child_environment(void)
1021{
1022 return sshpam_env;
1023}
1024
1025char **
1026fetch_pam_environment(void)
1027{
1028 return (pam_getenvlist(sshpam_handle));
1029}
1030
1031void
1032free_pam_environment(char **env)
1033{
1034 char **envp;
1035
1036 if (env == NULL)
1037 return;
1038
1039 for (envp = env; *envp; envp++)
1040 xfree(*envp);
1041 xfree(env);
1042}
1043
1044/*
1045 * "Blind" conversation function for password authentication. Assumes that
1046 * echo-off prompts are for the password and stores messages for later
1047 * display.
1048 */
1049static int
1050sshpam_passwd_conv(int n, struct pam_message **msg,
1051 struct pam_response **resp, void *data)
1052{
1053 struct pam_response *reply;
1054 int i;
1055 size_t len;
1056
1057 debug3("PAM: %s called with %d messages", __func__, n);
1058
1059 *resp = NULL;
1060
1061 if (n <= 0 || n > PAM_MAX_NUM_MSG)
1062 return (PAM_CONV_ERR);
1063
1064 if ((reply = malloc(n * sizeof(*reply))) == NULL)
1065 return (PAM_CONV_ERR);
1066 memset(reply, 0, n * sizeof(*reply));
1067
1068 for (i = 0; i < n; ++i) {
1069 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1070 case PAM_PROMPT_ECHO_OFF:
1071 if (sshpam_password == NULL)
1072 goto fail;
1073 if ((reply[i].resp = strdup(sshpam_password)) == NULL)
1074 goto fail;
1075 reply[i].resp_retcode = PAM_SUCCESS;
1076 break;
1077 case PAM_ERROR_MSG:
1078 case PAM_TEXT_INFO:
1079 len = strlen(PAM_MSG_MEMBER(msg, i, msg));
1080 if (len > 0) {
1081 buffer_append(&loginmsg,
1082 PAM_MSG_MEMBER(msg, i, msg), len);
1083 buffer_append(&loginmsg, "\n", 1);
1084 }
1085 if ((reply[i].resp = strdup("")) == NULL)
1086 goto fail;
1087 reply[i].resp_retcode = PAM_SUCCESS;
1088 break;
1089 default:
1090 goto fail;
1091 }
1092 }
1093 *resp = reply;
1094 return (PAM_SUCCESS);
1095
1096 fail:
1097 for(i = 0; i < n; i++) {
1098 if (reply[i].resp != NULL)
1099 xfree(reply[i].resp);
1100 }
1101 xfree(reply);
1102 return (PAM_CONV_ERR);
1103}
1104
1105static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
1106
1107/*
1108 * Attempt password authentication via PAM
1109 */
1110int
1111sshpam_auth_passwd(Authctxt *authctxt, const char *password)
1112{
1113 int flags = (options.permit_empty_passwd == 0 ?
1114 PAM_DISALLOW_NULL_AUTHTOK : 0);
1115
1116 if (!options.use_pam || sshpam_handle == NULL)
1117 fatal("PAM: %s called when PAM disabled or failed to "
1118 "initialise.", __func__);
1119
1120 sshpam_password = password;
1121 sshpam_authctxt = authctxt;
1122
1123 /*
1124 * If the user logging in is invalid, or is root but is not permitted
1125 * by PermitRootLogin, use an invalid password to prevent leaking
1126 * information via timing (eg if the PAM config has a delay on fail).
1127 */
1128 if (!sshpam_login_allowed(authctxt))
1129 sshpam_password = badpw;
1130
1131 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1132 (const void *)&passwd_conv);
1133 if (sshpam_err != PAM_SUCCESS)
1134 fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
1135 pam_strerror(sshpam_handle, sshpam_err));
1136
1137 sshpam_err = pam_authenticate(sshpam_handle, flags);
1138 sshpam_password = NULL;
1139 if (sshpam_err == PAM_SUCCESS && sshpam_login_allowed(authctxt)) {
1140 debug("PAM: password authentication accepted for %.100s",
1141 authctxt->user);
1142 return 1;
1143 } else {
1144 debug("PAM: password authentication failed for %.100s: %s",
1145 authctxt->valid ? authctxt->user : "an illegal user",
1146 pam_strerror(sshpam_handle, sshpam_err));
1147 return 0;
1148 }
1149}
1150#endif /* USE_PAM */
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