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