OpenSSH: Add local patches.
[dragonfly.git] / crypto / openssh / auth-pam.c
CommitLineData
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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
e9778795
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48/* Based on FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des */
49
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50#include "includes.h"
51
52#include <sys/types.h>
53#include <sys/stat.h>
54#include <sys/wait.h>
55
56#include <errno.h>
57#include <signal.h>
58#include <stdarg.h>
59#include <string.h>
60#include <unistd.h>
61
62#ifdef USE_PAM
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>
67#endif
68
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69#if !defined(SSHD_PAM_SERVICE)
70extern char *__progname;
71# define SSHD_PAM_SERVICE __progname
72#endif
73
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74/* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */
75#ifdef PAM_SUN_CODEBASE
e9778795 76# define sshpam_const /* Solaris, HP-UX, SunOS */
16c343f1 77#else
e9778795 78# define sshpam_const const /* LinuxPAM, OpenPAM, AIX */
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79#endif
80
81/* Ambiguity in spec: is it an array of pointers or a pointer to an array? */
82#ifdef PAM_SUN_CODEBASE
83# define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member)
84#else
85# define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member)
86#endif
87
88#include "xmalloc.h"
664f4763 89#include "sshbuf.h"
90#include "ssherr.h"
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91#include "hostfile.h"
92#include "auth.h"
93#include "auth-pam.h"
94#include "canohost.h"
95#include "log.h"
96#include "msg.h"
97#include "packet.h"
98#include "misc.h"
99#include "servconf.h"
100#include "ssh2.h"
101#include "auth-options.h"
102#ifdef GSSAPI
103#include "ssh-gss.h"
104#endif
105#include "monitor_wrap.h"
106
107extern ServerOptions options;
664f4763 108extern struct sshbuf *loginmsg;
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109extern u_int utmp_len;
110
111/* so we don't silently change behaviour */
112#ifdef USE_POSIX_THREADS
113# error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK"
114#endif
115
116/*
117 * Formerly known as USE_POSIX_THREADS, using this is completely unsupported
118 * and generally a bad idea. Use at own risk and do not expect support if
119 * this breaks.
120 */
121#ifdef UNSUPPORTED_POSIX_THREADS_HACK
122#include <pthread.h>
123/*
124 * Avoid namespace clash when *not* using pthreads for systems *with*
125 * pthreads, which unconditionally define pthread_t via sys/types.h
126 * (e.g. Linux)
127 */
128typedef pthread_t sp_pthread_t;
129#else
130typedef pid_t sp_pthread_t;
664f4763 131#define pthread_exit fake_pthread_exit
132#define pthread_create fake_pthread_create
133#define pthread_cancel fake_pthread_cancel
134#define pthread_join fake_pthread_join
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135#endif
136
137struct pam_ctxt {
138 sp_pthread_t pam_thread;
139 int pam_psock;
140 int pam_csock;
141 int pam_done;
142};
143
144static void sshpam_free_ctx(void *);
145static struct pam_ctxt *cleanup_ctxt;
146
147#ifndef UNSUPPORTED_POSIX_THREADS_HACK
148/*
149 * Simulate threads with processes.
150 */
151
152static int sshpam_thread_status = -1;
153static mysig_t sshpam_oldsig;
154
155static void
156sshpam_sigchld_handler(int sig)
157{
158 signal(SIGCHLD, SIG_DFL);
159 if (cleanup_ctxt == NULL)
160 return; /* handler called after PAM cleanup, shouldn't happen */
161 if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
162 <= 0) {
163 /* PAM thread has not exitted, privsep slave must have */
164 kill(cleanup_ctxt->pam_thread, SIGTERM);
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165 while (waitpid(cleanup_ctxt->pam_thread,
166 &sshpam_thread_status, 0) == -1) {
167 if (errno == EINTR)
168 continue;
169 return;
170 }
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171 }
172 if (WIFSIGNALED(sshpam_thread_status) &&
173 WTERMSIG(sshpam_thread_status) == SIGTERM)
174 return; /* terminated by pthread_cancel */
175 if (!WIFEXITED(sshpam_thread_status))
176 sigdie("PAM: authentication thread exited unexpectedly");
177 if (WEXITSTATUS(sshpam_thread_status) != 0)
178 sigdie("PAM: authentication thread exited uncleanly");
179}
180
181/* ARGSUSED */
182static void
183pthread_exit(void *value)
184{
185 _exit(0);
186}
187
188/* ARGSUSED */
189static int
190pthread_create(sp_pthread_t *thread, const void *attr,
191 void *(*thread_start)(void *), void *arg)
192{
193 pid_t pid;
194 struct pam_ctxt *ctx = arg;
195
196 sshpam_thread_status = -1;
197 switch ((pid = fork())) {
198 case -1:
199 error("fork(): %s", strerror(errno));
200 return (-1);
201 case 0:
202 close(ctx->pam_psock);
203 ctx->pam_psock = -1;
204 thread_start(arg);
205 _exit(1);
206 default:
207 *thread = pid;
208 close(ctx->pam_csock);
209 ctx->pam_csock = -1;
210 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
211 return (0);
212 }
213}
214
215static int
216pthread_cancel(sp_pthread_t thread)
217{
218 signal(SIGCHLD, sshpam_oldsig);
219 return (kill(thread, SIGTERM));
220}
221
222/* ARGSUSED */
223static int
224pthread_join(sp_pthread_t thread, void **value)
225{
226 int status;
227
228 if (sshpam_thread_status != -1)
229 return (sshpam_thread_status);
230 signal(SIGCHLD, sshpam_oldsig);
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231 while (waitpid(thread, &status, 0) == -1) {
232 if (errno == EINTR)
233 continue;
234 fatal("%s: waitpid: %s", __func__, strerror(errno));
235 }
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236 return (status);
237}
238#endif
239
240
241static pam_handle_t *sshpam_handle = NULL;
242static int sshpam_err = 0;
243static int sshpam_authenticated = 0;
244static int sshpam_session_open = 0;
245static int sshpam_cred_established = 0;
246static int sshpam_account_status = -1;
e9778795 247static int sshpam_maxtries_reached = 0;
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248static char **sshpam_env = NULL;
249static Authctxt *sshpam_authctxt = NULL;
250static const char *sshpam_password = NULL;
664f4763 251static char *sshpam_rhost = NULL;
252static char *sshpam_laddr = NULL;
253static char *sshpam_conninfo = NULL;
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254
255/* Some PAM implementations don't implement this */
256#ifndef HAVE_PAM_GETENVLIST
257static char **
258pam_getenvlist(pam_handle_t *pamh)
259{
260 /*
261 * XXX - If necessary, we can still support envrionment passing
262 * for platforms without pam_getenvlist by searching for known
263 * env vars (e.g. KRB5CCNAME) from the PAM environment.
264 */
265 return NULL;
266}
267#endif
268
269/*
270 * Some platforms, notably Solaris, do not enforce password complexity
271 * rules during pam_chauthtok() if the real uid of the calling process
272 * is 0, on the assumption that it's being called by "passwd" run by root.
273 * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
274 * the right thing.
275 */
276#ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
277static int
278sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
279{
280 int result;
281
282 if (sshpam_authctxt == NULL)
283 fatal("PAM: sshpam_authctxt not initialized");
284 if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
285 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
286 result = pam_chauthtok(pamh, flags);
287 if (setreuid(0, -1) == -1)
288 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
289 return result;
290}
291# define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b)))
292#endif
293
ca56dc39 294static void
16c343f1
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295sshpam_password_change_required(int reqd)
296{
664f4763 297 extern struct sshauthopt *auth_opts;
298 static int saved_port, saved_agent, saved_x11;
299
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300 debug3("%s %d", __func__, reqd);
301 if (sshpam_authctxt == NULL)
302 fatal("%s: PAM authctxt not initialized", __func__);
303 sshpam_authctxt->force_pwchange = reqd;
304 if (reqd) {
664f4763 305 saved_port = auth_opts->permit_port_forwarding_flag;
306 saved_agent = auth_opts->permit_agent_forwarding_flag;
307 saved_x11 = auth_opts->permit_x11_forwarding_flag;
308 auth_opts->permit_port_forwarding_flag = 0;
309 auth_opts->permit_agent_forwarding_flag = 0;
310 auth_opts->permit_x11_forwarding_flag = 0;
16c343f1 311 } else {
664f4763 312 if (saved_port)
313 auth_opts->permit_port_forwarding_flag = saved_port;
314 if (saved_agent)
315 auth_opts->permit_agent_forwarding_flag = saved_agent;
316 if (saved_x11)
317 auth_opts->permit_x11_forwarding_flag = saved_x11;
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PA
318 }
319}
320
321/* Import regular and PAM environment from subprocess */
322static void
664f4763 323import_environments(struct sshbuf *b)
16c343f1
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324{
325 char *env;
664f4763 326 u_int n, i, num_env;
327 int r;
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328
329 debug3("PAM: %s entering", __func__);
330
331#ifndef UNSUPPORTED_POSIX_THREADS_HACK
332 /* Import variables set by do_pam_account */
664f4763 333 if ((r = sshbuf_get_u32(b, &n)) != 0)
334 fatal("%s: buffer error: %s", __func__, ssh_err(r));
335 if (n > INT_MAX)
336 fatal("%s: invalid PAM account status %u", __func__, n);
337 sshpam_account_status = (int)n;
338 if ((r = sshbuf_get_u32(b, &n)) != 0)
339 fatal("%s: buffer error: %s", __func__, ssh_err(r));
340 sshpam_password_change_required(n != 0);
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341
342 /* Import environment from subprocess */
664f4763 343 if ((r = sshbuf_get_u32(b, &num_env)) != 0)
344 fatal("%s: buffer error: %s", __func__, ssh_err(r));
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PA
345 if (num_env > 1024)
346 fatal("%s: received %u environment variables, expected <= 1024",
347 __func__, num_env);
348 sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env));
349 debug3("PAM: num env strings %d", num_env);
664f4763 350 for(i = 0; i < num_env; i++) {
351 if ((r = sshbuf_get_cstring(b, &(sshpam_env[i]), NULL)) != 0)
352 fatal("%s: buffer error: %s", __func__, ssh_err(r));
353 }
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PA
354 sshpam_env[num_env] = NULL;
355
356 /* Import PAM environment from subprocess */
664f4763 357 if ((r = sshbuf_get_u32(b, &num_env)) != 0)
358 fatal("%s: buffer error: %s", __func__, ssh_err(r));
16c343f1 359 debug("PAM: num PAM env strings %d", num_env);
664f4763 360 for (i = 0; i < num_env; i++) {
361 if ((r = sshbuf_get_cstring(b, &env, NULL)) != 0)
362 fatal("%s: buffer error: %s", __func__, ssh_err(r));
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363#ifdef HAVE_PAM_PUTENV
364 /* Errors are not fatal here */
664f4763 365 if ((r = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
16c343f1 366 error("PAM: pam_putenv: %s",
664f4763 367 pam_strerror(sshpam_handle, r));
16c343f1
PA
368 }
369#endif
664f4763 370 /* XXX leak env? */
16c343f1
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371 }
372#endif
373}
374
375/*
376 * Conversation function for authentication thread.
377 */
378static int
379sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
380 struct pam_response **resp, void *data)
381{
664f4763 382 struct sshbuf *buffer;
16c343f1
PA
383 struct pam_ctxt *ctxt;
384 struct pam_response *reply;
664f4763 385 int r, i;
386 u_char status;
16c343f1
PA
387
388 debug3("PAM: %s entering, %d messages", __func__, n);
389 *resp = NULL;
390
391 if (data == NULL) {
392 error("PAM: conversation function passed a null context");
393 return (PAM_CONV_ERR);
394 }
395 ctxt = data;
396 if (n <= 0 || n > PAM_MAX_NUM_MSG)
397 return (PAM_CONV_ERR);
398
399 if ((reply = calloc(n, sizeof(*reply))) == NULL)
664f4763 400 return PAM_CONV_ERR;
401 if ((buffer = sshbuf_new()) == NULL) {
402 free(reply);
403 return PAM_CONV_ERR;
404 }
16c343f1 405
16c343f1
PA
406 for (i = 0; i < n; ++i) {
407 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
408 case PAM_PROMPT_ECHO_OFF:
16c343f1 409 case PAM_PROMPT_ECHO_ON:
664f4763 410 if ((r = sshbuf_put_cstring(buffer,
411 PAM_MSG_MEMBER(msg, i, msg))) != 0)
412 fatal("%s: buffer error: %s",
413 __func__, ssh_err(r));
16c343f1 414 if (ssh_msg_send(ctxt->pam_csock,
664f4763 415 PAM_MSG_MEMBER(msg, i, msg_style), buffer) == -1)
16c343f1 416 goto fail;
664f4763 417
418 if (ssh_msg_recv(ctxt->pam_csock, buffer) == -1)
16c343f1 419 goto fail;
664f4763 420 if ((r = sshbuf_get_u8(buffer, &status)) != 0)
421 fatal("%s: buffer error: %s",
422 __func__, ssh_err(r));
423 if (status != PAM_AUTHTOK)
16c343f1 424 goto fail;
664f4763 425 if ((r = sshbuf_get_cstring(buffer,
426 &reply[i].resp, NULL)) != 0)
427 fatal("%s: buffer error: %s",
428 __func__, ssh_err(r));
16c343f1
PA
429 break;
430 case PAM_ERROR_MSG:
16c343f1 431 case PAM_TEXT_INFO:
664f4763 432 if ((r = sshbuf_put_cstring(buffer,
433 PAM_MSG_MEMBER(msg, i, msg))) != 0)
434 fatal("%s: buffer error: %s",
435 __func__, ssh_err(r));
16c343f1 436 if (ssh_msg_send(ctxt->pam_csock,
664f4763 437 PAM_MSG_MEMBER(msg, i, msg_style), buffer) == -1)
16c343f1
PA
438 goto fail;
439 break;
440 default:
441 goto fail;
442 }
664f4763 443 sshbuf_reset(buffer);
16c343f1 444 }
664f4763 445 sshbuf_free(buffer);
16c343f1
PA
446 *resp = reply;
447 return (PAM_SUCCESS);
448
449 fail:
450 for(i = 0; i < n; i++) {
36e94dc5 451 free(reply[i].resp);
16c343f1 452 }
36e94dc5 453 free(reply);
664f4763 454 sshbuf_free(buffer);
16c343f1
PA
455 return (PAM_CONV_ERR);
456}
457
458/*
459 * Authentication thread.
460 */
461static void *
462sshpam_thread(void *ctxtp)
463{
464 struct pam_ctxt *ctxt = ctxtp;
664f4763 465 struct sshbuf *buffer = NULL;
16c343f1 466 struct pam_conv sshpam_conv;
664f4763 467 int r, flags = (options.permit_empty_passwd == 0 ?
16c343f1
PA
468 PAM_DISALLOW_NULL_AUTHTOK : 0);
469#ifndef UNSUPPORTED_POSIX_THREADS_HACK
470 extern char **environ;
471 char **env_from_pam;
472 u_int i;
473 const char *pam_user;
474 const char **ptr_pam_user = &pam_user;
475 char *tz = getenv("TZ");
476
36e94dc5 477 sshpam_err = pam_get_item(sshpam_handle, PAM_USER,
16c343f1 478 (sshpam_const void **)ptr_pam_user);
36e94dc5
PA
479 if (sshpam_err != PAM_SUCCESS)
480 goto auth_fail;
16c343f1
PA
481
482 environ[0] = NULL;
483 if (tz != NULL)
484 if (setenv("TZ", tz, 1) == -1)
485 error("PAM: could not set TZ environment: %s",
486 strerror(errno));
487
488 if (sshpam_authctxt != NULL) {
489 setproctitle("%s [pam]",
490 sshpam_authctxt->valid ? pam_user : "unknown");
491 }
492#endif
493
494 sshpam_conv.conv = sshpam_thread_conv;
495 sshpam_conv.appdata_ptr = ctxt;
496
497 if (sshpam_authctxt == NULL)
498 fatal("%s: PAM authctxt not initialized", __func__);
499
664f4763 500 if ((buffer = sshbuf_new()) == NULL)
501 fatal("%s: sshbuf_new failed", __func__);
502
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PA
503 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
504 (const void *)&sshpam_conv);
505 if (sshpam_err != PAM_SUCCESS)
506 goto auth_fail;
507 sshpam_err = pam_authenticate(sshpam_handle, flags);
e9778795
PA
508 if (sshpam_err == PAM_MAXTRIES)
509 sshpam_set_maxtries_reached(1);
16c343f1
PA
510 if (sshpam_err != PAM_SUCCESS)
511 goto auth_fail;
512
ce74baca
MD
513 if (!do_pam_account()) {
514 sshpam_err = PAM_ACCT_EXPIRED;
515 goto auth_fail;
516 }
517 if (sshpam_authctxt->force_pwchange) {
518 sshpam_err = pam_chauthtok(sshpam_handle,
519 PAM_CHANGE_EXPIRED_AUTHTOK);
520 if (sshpam_err != PAM_SUCCESS)
16c343f1 521 goto auth_fail;
ce74baca 522 sshpam_password_change_required(0);
16c343f1
PA
523 }
524
664f4763 525 if ((r = sshbuf_put_cstring(buffer, "OK")) != 0)
526 fatal("%s: buffer error: %s", __func__, ssh_err(r));
16c343f1
PA
527
528#ifndef UNSUPPORTED_POSIX_THREADS_HACK
529 /* Export variables set by do_pam_account */
664f4763 530 if ((r = sshbuf_put_u32(buffer, sshpam_account_status)) != 0 ||
531 (r = sshbuf_put_u32(buffer, sshpam_authctxt->force_pwchange)) != 0)
532 fatal("%s: buffer error: %s", __func__, ssh_err(r));
16c343f1
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533
534 /* Export any environment strings set in child */
664f4763 535 for (i = 0; environ[i] != NULL; i++) {
536 /* Count */
537 if (i > INT_MAX)
538 fatal("%s: too many enviornment strings", __func__);
539 }
540 if ((r = sshbuf_put_u32(buffer, i)) != 0)
541 fatal("%s: buffer error: %s", __func__, ssh_err(r));
542 for (i = 0; environ[i] != NULL; i++) {
543 if ((r = sshbuf_put_cstring(buffer, environ[i])) != 0)
544 fatal("%s: buffer error: %s", __func__, ssh_err(r));
545 }
16c343f1
PA
546 /* Export any environment strings set by PAM in child */
547 env_from_pam = pam_getenvlist(sshpam_handle);
664f4763 548 for (i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) {
549 /* Count */
550 if (i > INT_MAX)
551 fatal("%s: too many PAM enviornment strings", __func__);
552 }
553 if ((r = sshbuf_put_u32(buffer, i)) != 0)
554 fatal("%s: buffer error: %s", __func__, ssh_err(r));
555 for (i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) {
556 if ((r = sshbuf_put_cstring(buffer, env_from_pam[i])) != 0)
557 fatal("%s: buffer error: %s", __func__, ssh_err(r));
558 }
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559#endif /* UNSUPPORTED_POSIX_THREADS_HACK */
560
561 /* XXX - can't do much about an error here */
664f4763 562 ssh_msg_send(ctxt->pam_csock, sshpam_err, buffer);
563 sshbuf_free(buffer);
16c343f1
PA
564 pthread_exit(NULL);
565
566 auth_fail:
664f4763 567 if ((r = sshbuf_put_cstring(buffer,
568 pam_strerror(sshpam_handle, sshpam_err))) != 0)
569 fatal("%s: buffer error: %s", __func__, ssh_err(r));
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PA
570 /* XXX - can't do much about an error here */
571 if (sshpam_err == PAM_ACCT_EXPIRED)
664f4763 572 ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, buffer);
e9778795 573 else if (sshpam_maxtries_reached)
664f4763 574 ssh_msg_send(ctxt->pam_csock, PAM_MAXTRIES, buffer);
16c343f1 575 else
664f4763 576 ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, buffer);
577 sshbuf_free(buffer);
16c343f1
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578 pthread_exit(NULL);
579
580 return (NULL); /* Avoid warning for non-pthread case */
581}
582
583void
584sshpam_thread_cleanup(void)
585{
586 struct pam_ctxt *ctxt = cleanup_ctxt;
587
588 debug3("PAM: %s entering", __func__);
589 if (ctxt != NULL && ctxt->pam_thread != 0) {
590 pthread_cancel(ctxt->pam_thread);
591 pthread_join(ctxt->pam_thread, NULL);
592 close(ctxt->pam_psock);
593 close(ctxt->pam_csock);
594 memset(ctxt, 0, sizeof(*ctxt));
595 cleanup_ctxt = NULL;
596 }
597}
598
599static int
600sshpam_null_conv(int n, sshpam_const struct pam_message **msg,
601 struct pam_response **resp, void *data)
602{
603 debug3("PAM: %s entering, %d messages", __func__, n);
604 return (PAM_CONV_ERR);
605}
606
607static struct pam_conv null_conv = { sshpam_null_conv, NULL };
608
609static int
610sshpam_store_conv(int n, sshpam_const struct pam_message **msg,
611 struct pam_response **resp, void *data)
612{
613 struct pam_response *reply;
664f4763 614 int r, i;
16c343f1
PA
615
616 debug3("PAM: %s called with %d messages", __func__, n);
617 *resp = NULL;
618
619 if (n <= 0 || n > PAM_MAX_NUM_MSG)
620 return (PAM_CONV_ERR);
621
622 if ((reply = calloc(n, sizeof(*reply))) == NULL)
623 return (PAM_CONV_ERR);
624
625 for (i = 0; i < n; ++i) {
626 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
627 case PAM_ERROR_MSG:
628 case PAM_TEXT_INFO:
664f4763 629 if ((r = sshbuf_putf(loginmsg, "%s\n",
630 PAM_MSG_MEMBER(msg, i, msg))) != 0)
631 fatal("%s: buffer error: %s",
632 __func__, ssh_err(r));
16c343f1
PA
633 reply[i].resp_retcode = PAM_SUCCESS;
634 break;
635 default:
636 goto fail;
637 }
638 }
639 *resp = reply;
640 return (PAM_SUCCESS);
641
642 fail:
643 for(i = 0; i < n; i++) {
36e94dc5 644 free(reply[i].resp);
16c343f1 645 }
36e94dc5 646 free(reply);
16c343f1
PA
647 return (PAM_CONV_ERR);
648}
649
650static struct pam_conv store_conv = { sshpam_store_conv, NULL };
651
652void
653sshpam_cleanup(void)
654{
655 if (sshpam_handle == NULL || (use_privsep && !mm_is_monitor()))
656 return;
657 debug("PAM: cleanup");
658 pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
16c343f1
PA
659 if (sshpam_session_open) {
660 debug("PAM: closing session");
661 pam_close_session(sshpam_handle, PAM_SILENT);
662 sshpam_session_open = 0;
663 }
40c002af
PA
664 if (sshpam_cred_established) {
665 debug("PAM: deleting credentials");
666 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
667 sshpam_cred_established = 0;
668 }
16c343f1
PA
669 sshpam_authenticated = 0;
670 pam_end(sshpam_handle, sshpam_err);
671 sshpam_handle = NULL;
672}
673
674static int
664f4763 675sshpam_init(struct ssh *ssh, Authctxt *authctxt)
16c343f1 676{
664f4763 677 const char *pam_user, *user = authctxt->user;
16c343f1
PA
678 const char **ptr_pam_user = &pam_user;
679
664f4763 680 if (sshpam_handle == NULL) {
681 if (ssh == NULL) {
682 fatal("%s: called initially with no "
683 "packet context", __func__);
684 }
685 } if (sshpam_handle != NULL) {
16c343f1
PA
686 /* We already have a PAM context; check if the user matches */
687 sshpam_err = pam_get_item(sshpam_handle,
688 PAM_USER, (sshpam_const void **)ptr_pam_user);
689 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
690 return (0);
691 pam_end(sshpam_handle, sshpam_err);
692 sshpam_handle = NULL;
693 }
694 debug("PAM: initializing for \"%s\"", user);
695 sshpam_err =
696 pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
697 sshpam_authctxt = authctxt;
698
699 if (sshpam_err != PAM_SUCCESS) {
700 pam_end(sshpam_handle, sshpam_err);
701 sshpam_handle = NULL;
702 return (-1);
703 }
664f4763 704
705 if (ssh != NULL && sshpam_rhost == NULL) {
706 /*
707 * We need to cache these as we don't have packet context
708 * during the kbdint flow.
709 */
710 sshpam_rhost = xstrdup(auth_get_canonical_hostname(ssh,
711 options.use_dns));
712 sshpam_laddr = get_local_ipaddr(
713 ssh_packet_get_connection_in(ssh));
714 xasprintf(&sshpam_conninfo, "SSH_CONNECTION=%.50s %d %.50s %d",
715 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
716 sshpam_laddr, ssh_local_port(ssh));
717 }
718 if (sshpam_rhost != NULL) {
719 debug("PAM: setting PAM_RHOST to \"%s\"", sshpam_rhost);
720 sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST,
721 sshpam_rhost);
722 if (sshpam_err != PAM_SUCCESS) {
723 pam_end(sshpam_handle, sshpam_err);
724 sshpam_handle = NULL;
725 return (-1);
726 }
727 /* Put SSH_CONNECTION in the PAM environment too */
728 pam_putenv(sshpam_handle, sshpam_conninfo);
16c343f1 729 }
664f4763 730
16c343f1
PA
731#ifdef PAM_TTY_KLUDGE
732 /*
733 * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
734 * sshd doesn't set the tty until too late in the auth process and
735 * may not even set one (for tty-less connections)
736 */
737 debug("PAM: setting PAM_TTY to \"ssh\"");
738 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
739 if (sshpam_err != PAM_SUCCESS) {
740 pam_end(sshpam_handle, sshpam_err);
741 sshpam_handle = NULL;
742 return (-1);
743 }
744#endif
745 return (0);
746}
747
664f4763 748static void
749expose_authinfo(const char *caller)
750{
751 char *auth_info;
752
753 /*
754 * Expose authentication information to PAM.
755 * The environment variable is versioned. Please increment the
756 * version suffix if the format of session_info changes.
757 */
758 if (sshpam_authctxt->session_info == NULL)
759 auth_info = xstrdup("");
760 else if ((auth_info = sshbuf_dup_string(
761 sshpam_authctxt->session_info)) == NULL)
762 fatal("%s: sshbuf_dup_string failed", __func__);
763
764 debug2("%s: auth information in SSH_AUTH_INFO_0", caller);
765 do_pam_putenv("SSH_AUTH_INFO_0", auth_info);
766 free(auth_info);
767}
768
16c343f1
PA
769static void *
770sshpam_init_ctx(Authctxt *authctxt)
771{
772 struct pam_ctxt *ctxt;
773 int socks[2];
774
775 debug3("PAM: %s entering", __func__);
776 /*
777 * Refuse to start if we don't have PAM enabled or do_pam_account
778 * has previously failed.
779 */
780 if (!options.use_pam || sshpam_account_status == 0)
781 return NULL;
782
783 /* Initialize PAM */
664f4763 784 if (sshpam_init(NULL, authctxt) == -1) {
16c343f1
PA
785 error("PAM: initialization failed");
786 return (NULL);
787 }
788
664f4763 789 expose_authinfo(__func__);
16c343f1
PA
790 ctxt = xcalloc(1, sizeof *ctxt);
791
792 /* Start the authentication thread */
793 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
794 error("PAM: failed create sockets: %s", strerror(errno));
36e94dc5 795 free(ctxt);
16c343f1
PA
796 return (NULL);
797 }
798 ctxt->pam_psock = socks[0];
799 ctxt->pam_csock = socks[1];
800 if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
801 error("PAM: failed to start authentication thread: %s",
802 strerror(errno));
803 close(socks[0]);
804 close(socks[1]);
36e94dc5 805 free(ctxt);
16c343f1
PA
806 return (NULL);
807 }
808 cleanup_ctxt = ctxt;
809 return (ctxt);
810}
811
812static int
813sshpam_query(void *ctx, char **name, char **info,
814 u_int *num, char ***prompts, u_int **echo_on)
815{
664f4763 816 struct sshbuf *buffer;
16c343f1
PA
817 struct pam_ctxt *ctxt = ctx;
818 size_t plen;
819 u_char type;
820 char *msg;
821 size_t len, mlen;
664f4763 822 int r;
16c343f1
PA
823
824 debug3("PAM: %s entering", __func__);
664f4763 825 if ((buffer = sshbuf_new()) == NULL)
826 fatal("%s: sshbuf_new failed", __func__);
16c343f1
PA
827 *name = xstrdup("");
828 *info = xstrdup("");
829 *prompts = xmalloc(sizeof(char *));
830 **prompts = NULL;
831 plen = 0;
832 *echo_on = xmalloc(sizeof(u_int));
664f4763 833 while (ssh_msg_recv(ctxt->pam_psock, buffer) == 0) {
834 if ((r = sshbuf_get_u8(buffer, &type)) != 0 ||
835 (r = sshbuf_get_cstring(buffer, &msg, &mlen)) != 0)
836 fatal("%s: buffer error: %s", __func__, ssh_err(r));
16c343f1
PA
837 switch (type) {
838 case PAM_PROMPT_ECHO_ON:
839 case PAM_PROMPT_ECHO_OFF:
840 *num = 1;
841 len = plen + mlen + 1;
e9778795 842 **prompts = xreallocarray(**prompts, 1, len);
16c343f1
PA
843 strlcpy(**prompts + plen, msg, len - plen);
844 plen += mlen;
845 **echo_on = (type == PAM_PROMPT_ECHO_ON);
36e94dc5 846 free(msg);
16c343f1
PA
847 return (0);
848 case PAM_ERROR_MSG:
849 case PAM_TEXT_INFO:
850 /* accumulate messages */
851 len = plen + mlen + 2;
e9778795 852 **prompts = xreallocarray(**prompts, 1, len);
16c343f1
PA
853 strlcpy(**prompts + plen, msg, len - plen);
854 plen += mlen;
855 strlcat(**prompts + plen, "\n", len - plen);
856 plen++;
36e94dc5 857 free(msg);
16c343f1
PA
858 break;
859 case PAM_ACCT_EXPIRED:
e9778795
PA
860 case PAM_MAXTRIES:
861 if (type == PAM_ACCT_EXPIRED)
862 sshpam_account_status = 0;
863 if (type == PAM_MAXTRIES)
864 sshpam_set_maxtries_reached(1);
16c343f1
PA
865 /* FALLTHROUGH */
866 case PAM_AUTH_ERR:
867 debug3("PAM: %s", pam_strerror(sshpam_handle, type));
868 if (**prompts != NULL && strlen(**prompts) != 0) {
869 *info = **prompts;
870 **prompts = NULL;
871 *num = 0;
872 **echo_on = 0;
873 ctxt->pam_done = -1;
36e94dc5 874 free(msg);
16c343f1
PA
875 return 0;
876 }
877 /* FALLTHROUGH */
878 case PAM_SUCCESS:
879 if (**prompts != NULL) {
880 /* drain any accumulated messages */
881 debug("PAM: %s", **prompts);
664f4763 882 if ((r = sshbuf_put(loginmsg, **prompts,
883 strlen(**prompts))) != 0)
884 fatal("%s: buffer error: %s",
885 __func__, ssh_err(r));
36e94dc5 886 free(**prompts);
16c343f1
PA
887 **prompts = NULL;
888 }
889 if (type == PAM_SUCCESS) {
890 if (!sshpam_authctxt->valid ||
891 (sshpam_authctxt->pw->pw_uid == 0 &&
892 options.permit_root_login != PERMIT_YES))
893 fatal("Internal error: PAM auth "
894 "succeeded when it should have "
895 "failed");
664f4763 896 import_environments(buffer);
16c343f1
PA
897 *num = 0;
898 **echo_on = 0;
899 ctxt->pam_done = 1;
36e94dc5 900 free(msg);
16c343f1
PA
901 return (0);
902 }
903 error("PAM: %s for %s%.100s from %.100s", msg,
904 sshpam_authctxt->valid ? "" : "illegal user ",
664f4763 905 sshpam_authctxt->user, sshpam_rhost);
16c343f1
PA
906 /* FALLTHROUGH */
907 default:
908 *num = 0;
909 **echo_on = 0;
36e94dc5 910 free(msg);
16c343f1
PA
911 ctxt->pam_done = -1;
912 return (-1);
913 }
914 }
915 return (-1);
916}
917
e9778795
PA
918/*
919 * Returns a junk password of identical length to that the user supplied.
920 * Used to mitigate timing attacks against crypt(3)/PAM stacks that
921 * vary processing time in proportion to password length.
922 */
923static char *
924fake_password(const char *wire_password)
925{
926 const char junk[] = "\b\n\r\177INCORRECT";
927 char *ret = NULL;
928 size_t i, l = wire_password != NULL ? strlen(wire_password) : 0;
929
930 if (l >= INT_MAX)
931 fatal("%s: password length too long: %zu", __func__, l);
932
933 ret = malloc(l + 1);
ce74baca
MD
934 if (ret == NULL)
935 return NULL;
e9778795
PA
936 for (i = 0; i < l; i++)
937 ret[i] = junk[i % (sizeof(junk) - 1)];
938 ret[i] = '\0';
939 return ret;
940}
941
16c343f1
PA
942/* XXX - see also comment in auth-chall.c:verify_response */
943static int
944sshpam_respond(void *ctx, u_int num, char **resp)
945{
664f4763 946 struct sshbuf *buffer;
16c343f1 947 struct pam_ctxt *ctxt = ctx;
e9778795 948 char *fake;
664f4763 949 int r;
16c343f1
PA
950
951 debug2("PAM: %s entering, %u responses", __func__, num);
952 switch (ctxt->pam_done) {
953 case 1:
954 sshpam_authenticated = 1;
955 return (0);
956 case 0:
957 break;
958 default:
959 return (-1);
960 }
961 if (num != 1) {
962 error("PAM: expected one response, got %u", num);
963 return (-1);
964 }
664f4763 965 if ((buffer = sshbuf_new()) == NULL)
966 fatal("%s: sshbuf_new failed", __func__);
16c343f1
PA
967 if (sshpam_authctxt->valid &&
968 (sshpam_authctxt->pw->pw_uid != 0 ||
664f4763 969 options.permit_root_login == PERMIT_YES)) {
970 if ((r = sshbuf_put_cstring(buffer, *resp)) != 0)
971 fatal("%s: buffer error: %s", __func__, ssh_err(r));
972 } else {
e9778795 973 fake = fake_password(*resp);
664f4763 974 if ((r = sshbuf_put_cstring(buffer, fake)) != 0)
975 fatal("%s: buffer error: %s", __func__, ssh_err(r));
e9778795
PA
976 free(fake);
977 }
664f4763 978 if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, buffer) == -1) {
979 sshbuf_free(buffer);
16c343f1
PA
980 return (-1);
981 }
664f4763 982 sshbuf_free(buffer);
16c343f1
PA
983 return (1);
984}
985
986static void
987sshpam_free_ctx(void *ctxtp)
988{
989 struct pam_ctxt *ctxt = ctxtp;
990
991 debug3("PAM: %s entering", __func__);
992 sshpam_thread_cleanup();
36e94dc5 993 free(ctxt);
16c343f1
PA
994 /*
995 * We don't call sshpam_cleanup() here because we may need the PAM
996 * handle at a later stage, e.g. when setting up a session. It's
997 * still on the cleanup list, so pam_end() *will* be called before
998 * the server process terminates.
999 */
1000}
1001
1002KbdintDevice sshpam_device = {
1003 "pam",
1004 sshpam_init_ctx,
1005 sshpam_query,
1006 sshpam_respond,
1007 sshpam_free_ctx
1008};
1009
1010KbdintDevice mm_sshpam_device = {
1011 "pam",
1012 mm_sshpam_init_ctx,
1013 mm_sshpam_query,
1014 mm_sshpam_respond,
1015 mm_sshpam_free_ctx
1016};
1017
1018/*
1019 * This replaces auth-pam.c
1020 */
1021void
664f4763 1022start_pam(struct ssh *ssh)
16c343f1 1023{
664f4763 1024 Authctxt *authctxt = (Authctxt *)ssh->authctxt;
1025
16c343f1
PA
1026 if (!options.use_pam)
1027 fatal("PAM: initialisation requested when UsePAM=no");
1028
664f4763 1029 if (sshpam_init(ssh, authctxt) == -1)
16c343f1
PA
1030 fatal("PAM: initialisation failed");
1031}
1032
1033void
1034finish_pam(void)
1035{
1036 sshpam_cleanup();
1037}
1038
ce74baca 1039
16c343f1
PA
1040u_int
1041do_pam_account(void)
1042{
1043 debug("%s: called", __func__);
1044 if (sshpam_account_status != -1)
1045 return (sshpam_account_status);
1046
ce74baca
MD
1047 expose_authinfo(__func__);
1048
16c343f1
PA
1049 sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
1050 debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
1051 pam_strerror(sshpam_handle, sshpam_err));
1052
1053 if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
1054 sshpam_account_status = 0;
1055 return (sshpam_account_status);
1056 }
1057
1058 if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
1059 sshpam_password_change_required(1);
1060
1061 sshpam_account_status = 1;
1062 return (sshpam_account_status);
1063}
1064
16c343f1
PA
1065void
1066do_pam_setcred(int init)
1067{
1068 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1069 (const void *)&store_conv);
1070 if (sshpam_err != PAM_SUCCESS)
1071 fatal("PAM: failed to set PAM_CONV: %s",
1072 pam_strerror(sshpam_handle, sshpam_err));
1073 if (init) {
1074 debug("PAM: establishing credentials");
1075 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
1076 } else {
1077 debug("PAM: reinitializing credentials");
1078 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
1079 }
1080 if (sshpam_err == PAM_SUCCESS) {
1081 sshpam_cred_established = 1;
1082 return;
1083 }
1084 if (sshpam_authenticated)
1085 fatal("PAM: pam_setcred(): %s",
1086 pam_strerror(sshpam_handle, sshpam_err));
1087 else
1088 debug("PAM: pam_setcred(): %s",
1089 pam_strerror(sshpam_handle, sshpam_err));
1090}
1091
1092static int
1093sshpam_tty_conv(int n, sshpam_const struct pam_message **msg,
1094 struct pam_response **resp, void *data)
1095{
1096 char input[PAM_MAX_MSG_SIZE];
1097 struct pam_response *reply;
1098 int i;
1099
1100 debug3("PAM: %s called with %d messages", __func__, n);
1101
1102 *resp = NULL;
1103
1104 if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
1105 return (PAM_CONV_ERR);
1106
1107 if ((reply = calloc(n, sizeof(*reply))) == NULL)
1108 return (PAM_CONV_ERR);
1109
1110 for (i = 0; i < n; ++i) {
1111 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1112 case PAM_PROMPT_ECHO_OFF:
1113 reply[i].resp =
1114 read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
1115 RP_ALLOW_STDIN);
1116 reply[i].resp_retcode = PAM_SUCCESS;
1117 break;
1118 case PAM_PROMPT_ECHO_ON:
1119 fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
1120 if (fgets(input, sizeof input, stdin) == NULL)
1121 input[0] = '\0';
1122 if ((reply[i].resp = strdup(input)) == NULL)
1123 goto fail;
1124 reply[i].resp_retcode = PAM_SUCCESS;
1125 break;
1126 case PAM_ERROR_MSG:
1127 case PAM_TEXT_INFO:
1128 fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
1129 reply[i].resp_retcode = PAM_SUCCESS;
1130 break;
1131 default:
1132 goto fail;
1133 }
1134 }
1135 *resp = reply;
1136 return (PAM_SUCCESS);
1137
1138 fail:
1139 for(i = 0; i < n; i++) {
36e94dc5 1140 free(reply[i].resp);
16c343f1 1141 }
36e94dc5 1142 free(reply);
16c343f1
PA
1143 return (PAM_CONV_ERR);
1144}
1145
1146static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
1147
1148/*
1149 * XXX this should be done in the authentication phase, but ssh1 doesn't
1150 * support that
1151 */
1152void
1153do_pam_chauthtok(void)
1154{
1155 if (use_privsep)
1156 fatal("Password expired (unable to change with privsep)");
1157 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1158 (const void *)&tty_conv);
1159 if (sshpam_err != PAM_SUCCESS)
1160 fatal("PAM: failed to set PAM_CONV: %s",
1161 pam_strerror(sshpam_handle, sshpam_err));
1162 debug("PAM: changing password");
1163 sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
1164 if (sshpam_err != PAM_SUCCESS)
1165 fatal("PAM: pam_chauthtok(): %s",
1166 pam_strerror(sshpam_handle, sshpam_err));
1167}
1168
1169void
664f4763 1170do_pam_session(struct ssh *ssh)
16c343f1
PA
1171{
1172 debug3("PAM: opening session");
ce74baca
MD
1173
1174 expose_authinfo(__func__);
1175
16c343f1
PA
1176 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1177 (const void *)&store_conv);
1178 if (sshpam_err != PAM_SUCCESS)
1179 fatal("PAM: failed to set PAM_CONV: %s",
1180 pam_strerror(sshpam_handle, sshpam_err));
1181 sshpam_err = pam_open_session(sshpam_handle, 0);
1182 if (sshpam_err == PAM_SUCCESS)
1183 sshpam_session_open = 1;
1184 else {
1185 sshpam_session_open = 0;
664f4763 1186 auth_restrict_session(ssh);
16c343f1
PA
1187 error("PAM: pam_open_session(): %s",
1188 pam_strerror(sshpam_handle, sshpam_err));
1189 }
1190
1191}
1192
1193int
1194is_pam_session_open(void)
1195{
1196 return sshpam_session_open;
1197}
1198
1199/*
1200 * Set a PAM environment string. We need to do this so that the session
1201 * modules can handle things like Kerberos/GSI credentials that appear
1202 * during the ssh authentication process.
1203 */
1204int
1205do_pam_putenv(char *name, char *value)
1206{
1207 int ret = 1;
1208#ifdef HAVE_PAM_PUTENV
1209 char *compound;
1210 size_t len;
1211
1212 len = strlen(name) + strlen(value) + 2;
1213 compound = xmalloc(len);
1214
1215 snprintf(compound, len, "%s=%s", name, value);
1216 ret = pam_putenv(sshpam_handle, compound);
36e94dc5 1217 free(compound);
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1218#endif
1219
1220 return (ret);
1221}
1222
1223char **
1224fetch_pam_child_environment(void)
1225{
1226 return sshpam_env;
1227}
1228
1229char **
1230fetch_pam_environment(void)
1231{
1232 return (pam_getenvlist(sshpam_handle));
1233}
1234
1235void
1236free_pam_environment(char **env)
1237{
1238 char **envp;
1239
1240 if (env == NULL)
1241 return;
1242
1243 for (envp = env; *envp; envp++)
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1244 free(*envp);
1245 free(env);
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1246}
1247
1248/*
1249 * "Blind" conversation function for password authentication. Assumes that
1250 * echo-off prompts are for the password and stores messages for later
1251 * display.
1252 */
1253static int
1254sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg,
1255 struct pam_response **resp, void *data)
1256{
1257 struct pam_response *reply;
664f4763 1258 int r, i;
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1259 size_t len;
1260
1261 debug3("PAM: %s called with %d messages", __func__, n);
1262
1263 *resp = NULL;
1264
1265 if (n <= 0 || n > PAM_MAX_NUM_MSG)
1266 return (PAM_CONV_ERR);
1267
1268 if ((reply = calloc(n, sizeof(*reply))) == NULL)
1269 return (PAM_CONV_ERR);
1270
1271 for (i = 0; i < n; ++i) {
1272 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1273 case PAM_PROMPT_ECHO_OFF:
1274 if (sshpam_password == NULL)
1275 goto fail;
1276 if ((reply[i].resp = strdup(sshpam_password)) == NULL)
1277 goto fail;
1278 reply[i].resp_retcode = PAM_SUCCESS;
1279 break;
1280 case PAM_ERROR_MSG:
1281 case PAM_TEXT_INFO:
1282 len = strlen(PAM_MSG_MEMBER(msg, i, msg));
1283 if (len > 0) {
664f4763 1284 if ((r = sshbuf_putf(loginmsg, "%s\n",
1285 PAM_MSG_MEMBER(msg, i, msg))) != 0)
1286 fatal("%s: buffer error: %s",
1287 __func__, ssh_err(r));
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1288 }
1289 if ((reply[i].resp = strdup("")) == NULL)
1290 goto fail;
1291 reply[i].resp_retcode = PAM_SUCCESS;
1292 break;
1293 default:
1294 goto fail;
1295 }
1296 }
1297 *resp = reply;
1298 return (PAM_SUCCESS);
1299
1300 fail:
1301 for(i = 0; i < n; i++) {
36e94dc5 1302 free(reply[i].resp);
16c343f1 1303 }
36e94dc5 1304 free(reply);
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1305 return (PAM_CONV_ERR);
1306}
1307
1308static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
1309
1310/*
1311 * Attempt password authentication via PAM
1312 */
1313int
1314sshpam_auth_passwd(Authctxt *authctxt, const char *password)
1315{
1316 int flags = (options.permit_empty_passwd == 0 ?
1317 PAM_DISALLOW_NULL_AUTHTOK : 0);
e9778795 1318 char *fake = NULL;
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1319
1320 if (!options.use_pam || sshpam_handle == NULL)
1321 fatal("PAM: %s called when PAM disabled or failed to "
1322 "initialise.", __func__);
1323
1324 sshpam_password = password;
1325 sshpam_authctxt = authctxt;
1326
1327 /*
1328 * If the user logging in is invalid, or is root but is not permitted
1329 * by PermitRootLogin, use an invalid password to prevent leaking
1330 * information via timing (eg if the PAM config has a delay on fail).
1331 */
1332 if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
1333 options.permit_root_login != PERMIT_YES))
e9778795 1334 sshpam_password = fake = fake_password(password);
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1335
1336 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1337 (const void *)&passwd_conv);
1338 if (sshpam_err != PAM_SUCCESS)
1339 fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
1340 pam_strerror(sshpam_handle, sshpam_err));
1341
1342 sshpam_err = pam_authenticate(sshpam_handle, flags);
1343 sshpam_password = NULL;
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1344 free(fake);
1345 if (sshpam_err == PAM_MAXTRIES)
1346 sshpam_set_maxtries_reached(1);
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1347 if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
1348 debug("PAM: password authentication accepted for %.100s",
1349 authctxt->user);
1350 return 1;
1351 } else {
1352 debug("PAM: password authentication failed for %.100s: %s",
1353 authctxt->valid ? authctxt->user : "an illegal user",
1354 pam_strerror(sshpam_handle, sshpam_err));
1355 return 0;
1356 }
1357}
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1358
1359int
1360sshpam_get_maxtries_reached(void)
1361{
1362 return sshpam_maxtries_reached;
1363}
1364
1365void
1366sshpam_set_maxtries_reached(int reached)
1367{
1368 if (reached == 0 || sshpam_maxtries_reached)
1369 return;
1370 sshpam_maxtries_reached = 1;
1371 options.password_authentication = 0;
1372 options.kbd_interactive_authentication = 0;
1373 options.challenge_response_authentication = 0;
1374}
16c343f1 1375#endif /* USE_PAM */