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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 | ||
51 | #include <sys/types.h> | |
52 | #include <sys/stat.h> | |
53 | #include <sys/wait.h> | |
54 | ||
55 | #include <errno.h> | |
56 | #include <signal.h> | |
57 | #include <string.h> | |
58 | #include <unistd.h> | |
59 | ||
60 | #ifdef USE_PAM | |
61 | #if defined(HAVE_SECURITY_PAM_APPL_H) | |
62 | #include <security/pam_appl.h> | |
63 | #elif defined (HAVE_PAM_PAM_APPL_H) | |
64 | #include <pam/pam_appl.h> | |
65 | #endif | |
66 | ||
67 | /* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */ | |
68 | #ifdef PAM_SUN_CODEBASE | |
69 | # define sshpam_const /* Solaris, HP-UX, AIX */ | |
70 | #else | |
71 | # define sshpam_const const /* LinuxPAM, OpenPAM */ | |
72 | #endif | |
73 | ||
74 | /* Ambiguity in spec: is it an array of pointers or a pointer to an array? */ | |
75 | #ifdef PAM_SUN_CODEBASE | |
76 | # define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member) | |
77 | #else | |
78 | # define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member) | |
79 | #endif | |
80 | ||
81 | #include "xmalloc.h" | |
82 | #include "buffer.h" | |
83 | #include "key.h" | |
84 | #include "hostfile.h" | |
85 | #include "auth.h" | |
86 | #include "auth-pam.h" | |
87 | #include "canohost.h" | |
88 | #include "log.h" | |
89 | #include "msg.h" | |
90 | #include "packet.h" | |
91 | #include "misc.h" | |
92 | #include "servconf.h" | |
93 | #include "ssh2.h" | |
94 | #include "auth-options.h" | |
95 | #ifdef GSSAPI | |
96 | #include "ssh-gss.h" | |
97 | #endif | |
98 | #include "monitor_wrap.h" | |
99 | ||
100 | extern ServerOptions options; | |
101 | extern Buffer loginmsg; | |
102 | extern int compat20; | |
103 | extern u_int utmp_len; | |
104 | ||
105 | /* so we don't silently change behaviour */ | |
106 | #ifdef USE_POSIX_THREADS | |
107 | # error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK" | |
108 | #endif | |
109 | ||
110 | /* | |
111 | * Formerly known as USE_POSIX_THREADS, using this is completely unsupported | |
112 | * and generally a bad idea. Use at own risk and do not expect support if | |
113 | * this breaks. | |
114 | */ | |
115 | #ifdef UNSUPPORTED_POSIX_THREADS_HACK | |
116 | #include <pthread.h> | |
117 | /* | |
118 | * Avoid namespace clash when *not* using pthreads for systems *with* | |
119 | * pthreads, which unconditionally define pthread_t via sys/types.h | |
120 | * (e.g. Linux) | |
121 | */ | |
122 | typedef pthread_t sp_pthread_t; | |
123 | #else | |
124 | typedef pid_t sp_pthread_t; | |
125 | #endif | |
126 | ||
127 | struct pam_ctxt { | |
128 | sp_pthread_t pam_thread; | |
129 | int pam_psock; | |
130 | int pam_csock; | |
131 | int pam_done; | |
132 | }; | |
133 | ||
134 | static void sshpam_free_ctx(void *); | |
135 | static struct pam_ctxt *cleanup_ctxt; | |
136 | ||
137 | #ifndef UNSUPPORTED_POSIX_THREADS_HACK | |
138 | /* | |
139 | * Simulate threads with processes. | |
140 | */ | |
141 | ||
142 | static int sshpam_thread_status = -1; | |
143 | static mysig_t sshpam_oldsig; | |
144 | ||
145 | static void | |
146 | sshpam_sigchld_handler(int sig) | |
147 | { | |
148 | signal(SIGCHLD, SIG_DFL); | |
149 | if (cleanup_ctxt == NULL) | |
150 | return; /* handler called after PAM cleanup, shouldn't happen */ | |
151 | if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG) | |
152 | <= 0) { | |
153 | /* PAM thread has not exitted, privsep slave must have */ | |
154 | kill(cleanup_ctxt->pam_thread, SIGTERM); | |
155 | if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0) | |
156 | <= 0) | |
157 | return; /* could not wait */ | |
158 | } | |
159 | if (WIFSIGNALED(sshpam_thread_status) && | |
160 | WTERMSIG(sshpam_thread_status) == SIGTERM) | |
161 | return; /* terminated by pthread_cancel */ | |
162 | if (!WIFEXITED(sshpam_thread_status)) | |
163 | fatal("PAM: authentication thread exited unexpectedly"); | |
164 | if (WEXITSTATUS(sshpam_thread_status) != 0) | |
165 | fatal("PAM: authentication thread exited uncleanly"); | |
166 | } | |
167 | ||
168 | /* ARGSUSED */ | |
169 | static void | |
170 | pthread_exit(void *value) | |
171 | { | |
172 | _exit(0); | |
173 | } | |
174 | ||
175 | /* ARGSUSED */ | |
176 | static int | |
177 | pthread_create(sp_pthread_t *thread, const void *attr, | |
178 | void *(*thread_start)(void *), void *arg) | |
179 | { | |
180 | pid_t pid; | |
181 | struct pam_ctxt *ctx = arg; | |
182 | ||
183 | sshpam_thread_status = -1; | |
184 | switch ((pid = fork())) { | |
185 | case -1: | |
186 | error("fork(): %s", strerror(errno)); | |
187 | return (-1); | |
188 | case 0: | |
189 | close(ctx->pam_psock); | |
190 | ctx->pam_psock = -1; | |
191 | thread_start(arg); | |
192 | _exit(1); | |
193 | default: | |
194 | *thread = pid; | |
195 | close(ctx->pam_csock); | |
196 | ctx->pam_csock = -1; | |
197 | sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler); | |
198 | return (0); | |
199 | } | |
200 | } | |
201 | ||
202 | static int | |
203 | pthread_cancel(sp_pthread_t thread) | |
204 | { | |
205 | signal(SIGCHLD, sshpam_oldsig); | |
206 | return (kill(thread, SIGTERM)); | |
207 | } | |
208 | ||
209 | /* ARGSUSED */ | |
210 | static int | |
211 | pthread_join(sp_pthread_t thread, void **value) | |
212 | { | |
213 | int status; | |
214 | ||
215 | if (sshpam_thread_status != -1) | |
216 | return (sshpam_thread_status); | |
217 | signal(SIGCHLD, sshpam_oldsig); | |
218 | waitpid(thread, &status, 0); | |
219 | return (status); | |
220 | } | |
221 | #endif | |
222 | ||
223 | ||
224 | static pam_handle_t *sshpam_handle = NULL; | |
225 | static int sshpam_err = 0; | |
226 | static int sshpam_authenticated = 0; | |
227 | static int sshpam_session_open = 0; | |
228 | static int sshpam_cred_established = 0; | |
229 | static int sshpam_account_status = -1; | |
230 | static char **sshpam_env = NULL; | |
231 | static Authctxt *sshpam_authctxt = NULL; | |
232 | static const char *sshpam_password = NULL; | |
233 | static char badpw[] = "\b\n\r\177INCORRECT"; | |
234 | ||
235 | /* Some PAM implementations don't implement this */ | |
236 | #ifndef HAVE_PAM_GETENVLIST | |
237 | static char ** | |
238 | pam_getenvlist(pam_handle_t *pamh) | |
239 | { | |
240 | /* | |
241 | * XXX - If necessary, we can still support envrionment passing | |
242 | * for platforms without pam_getenvlist by searching for known | |
243 | * env vars (e.g. KRB5CCNAME) from the PAM environment. | |
244 | */ | |
245 | return NULL; | |
246 | } | |
247 | #endif | |
248 | ||
249 | /* | |
250 | * Some platforms, notably Solaris, do not enforce password complexity | |
251 | * rules during pam_chauthtok() if the real uid of the calling process | |
252 | * is 0, on the assumption that it's being called by "passwd" run by root. | |
253 | * This wraps pam_chauthtok and sets/restore the real uid so PAM will do | |
254 | * the right thing. | |
255 | */ | |
256 | #ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID | |
257 | static int | |
258 | sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags) | |
259 | { | |
260 | int result; | |
261 | ||
262 | if (sshpam_authctxt == NULL) | |
263 | fatal("PAM: sshpam_authctxt not initialized"); | |
264 | if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1) | |
265 | fatal("%s: setreuid failed: %s", __func__, strerror(errno)); | |
266 | result = pam_chauthtok(pamh, flags); | |
267 | if (setreuid(0, -1) == -1) | |
268 | fatal("%s: setreuid failed: %s", __func__, strerror(errno)); | |
269 | return result; | |
270 | } | |
271 | # define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b))) | |
272 | #endif | |
273 | ||
274 | void | |
275 | sshpam_password_change_required(int reqd) | |
276 | { | |
277 | debug3("%s %d", __func__, reqd); | |
278 | if (sshpam_authctxt == NULL) | |
279 | fatal("%s: PAM authctxt not initialized", __func__); | |
280 | sshpam_authctxt->force_pwchange = reqd; | |
281 | if (reqd) { | |
282 | no_port_forwarding_flag |= 2; | |
283 | no_agent_forwarding_flag |= 2; | |
284 | no_x11_forwarding_flag |= 2; | |
285 | } else { | |
286 | no_port_forwarding_flag &= ~2; | |
287 | no_agent_forwarding_flag &= ~2; | |
288 | no_x11_forwarding_flag &= ~2; | |
289 | } | |
290 | } | |
291 | ||
292 | /* Import regular and PAM environment from subprocess */ | |
293 | static void | |
294 | import_environments(Buffer *b) | |
295 | { | |
296 | char *env; | |
297 | u_int i, num_env; | |
298 | int err; | |
299 | ||
300 | debug3("PAM: %s entering", __func__); | |
301 | ||
302 | #ifndef UNSUPPORTED_POSIX_THREADS_HACK | |
303 | /* Import variables set by do_pam_account */ | |
304 | sshpam_account_status = buffer_get_int(b); | |
305 | sshpam_password_change_required(buffer_get_int(b)); | |
306 | ||
307 | /* Import environment from subprocess */ | |
308 | num_env = buffer_get_int(b); | |
309 | if (num_env > 1024) | |
310 | fatal("%s: received %u environment variables, expected <= 1024", | |
311 | __func__, num_env); | |
312 | sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env)); | |
313 | debug3("PAM: num env strings %d", num_env); | |
314 | for(i = 0; i < num_env; i++) | |
315 | sshpam_env[i] = buffer_get_string(b, NULL); | |
316 | ||
317 | sshpam_env[num_env] = NULL; | |
318 | ||
319 | /* Import PAM environment from subprocess */ | |
320 | num_env = buffer_get_int(b); | |
321 | debug("PAM: num PAM env strings %d", num_env); | |
322 | for(i = 0; i < num_env; i++) { | |
323 | env = buffer_get_string(b, NULL); | |
324 | ||
325 | #ifdef HAVE_PAM_PUTENV | |
326 | /* Errors are not fatal here */ | |
327 | if ((err = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) { | |
328 | error("PAM: pam_putenv: %s", | |
329 | pam_strerror(sshpam_handle, sshpam_err)); | |
330 | } | |
331 | #endif | |
332 | } | |
333 | #endif | |
334 | } | |
335 | ||
336 | /* | |
337 | * Conversation function for authentication thread. | |
338 | */ | |
339 | static int | |
340 | sshpam_thread_conv(int n, sshpam_const struct pam_message **msg, | |
341 | struct pam_response **resp, void *data) | |
342 | { | |
343 | Buffer buffer; | |
344 | struct pam_ctxt *ctxt; | |
345 | struct pam_response *reply; | |
346 | int i; | |
347 | ||
348 | debug3("PAM: %s entering, %d messages", __func__, n); | |
349 | *resp = NULL; | |
350 | ||
351 | if (data == NULL) { | |
352 | error("PAM: conversation function passed a null context"); | |
353 | return (PAM_CONV_ERR); | |
354 | } | |
355 | ctxt = data; | |
356 | if (n <= 0 || n > PAM_MAX_NUM_MSG) | |
357 | return (PAM_CONV_ERR); | |
358 | ||
359 | if ((reply = calloc(n, sizeof(*reply))) == NULL) | |
360 | return (PAM_CONV_ERR); | |
361 | ||
362 | buffer_init(&buffer); | |
363 | for (i = 0; i < n; ++i) { | |
364 | switch (PAM_MSG_MEMBER(msg, i, msg_style)) { | |
365 | case PAM_PROMPT_ECHO_OFF: | |
366 | buffer_put_cstring(&buffer, | |
367 | PAM_MSG_MEMBER(msg, i, msg)); | |
368 | if (ssh_msg_send(ctxt->pam_csock, | |
369 | PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1) | |
370 | goto fail; | |
371 | if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1) | |
372 | goto fail; | |
373 | if (buffer_get_char(&buffer) != PAM_AUTHTOK) | |
374 | goto fail; | |
375 | reply[i].resp = buffer_get_string(&buffer, NULL); | |
376 | break; | |
377 | case PAM_PROMPT_ECHO_ON: | |
378 | buffer_put_cstring(&buffer, | |
379 | PAM_MSG_MEMBER(msg, i, msg)); | |
380 | if (ssh_msg_send(ctxt->pam_csock, | |
381 | PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1) | |
382 | goto fail; | |
383 | if (ssh_msg_recv(ctxt->pam_csock, &buffer) == -1) | |
384 | goto fail; | |
385 | if (buffer_get_char(&buffer) != PAM_AUTHTOK) | |
386 | goto fail; | |
387 | reply[i].resp = buffer_get_string(&buffer, NULL); | |
388 | break; | |
389 | case PAM_ERROR_MSG: | |
390 | buffer_put_cstring(&buffer, | |
391 | PAM_MSG_MEMBER(msg, i, msg)); | |
392 | if (ssh_msg_send(ctxt->pam_csock, | |
393 | PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1) | |
394 | goto fail; | |
395 | break; | |
396 | case PAM_TEXT_INFO: | |
397 | buffer_put_cstring(&buffer, | |
398 | PAM_MSG_MEMBER(msg, i, msg)); | |
399 | if (ssh_msg_send(ctxt->pam_csock, | |
400 | PAM_MSG_MEMBER(msg, i, msg_style), &buffer) == -1) | |
401 | goto fail; | |
402 | break; | |
403 | default: | |
404 | goto fail; | |
405 | } | |
406 | buffer_clear(&buffer); | |
407 | } | |
408 | buffer_free(&buffer); | |
409 | *resp = reply; | |
410 | return (PAM_SUCCESS); | |
411 | ||
412 | fail: | |
413 | for(i = 0; i < n; i++) { | |
414 | if (reply[i].resp != NULL) | |
415 | xfree(reply[i].resp); | |
416 | } | |
417 | xfree(reply); | |
418 | buffer_free(&buffer); | |
419 | return (PAM_CONV_ERR); | |
420 | } | |
421 | ||
422 | /* | |
423 | * Authentication thread. | |
424 | */ | |
425 | static void * | |
426 | sshpam_thread(void *ctxtp) | |
427 | { | |
428 | struct pam_ctxt *ctxt = ctxtp; | |
429 | Buffer buffer; | |
430 | struct pam_conv sshpam_conv; | |
431 | int flags = (options.permit_empty_passwd == 0 ? | |
432 | PAM_DISALLOW_NULL_AUTHTOK : 0); | |
433 | #ifndef UNSUPPORTED_POSIX_THREADS_HACK | |
434 | extern char **environ; | |
435 | char **env_from_pam; | |
436 | u_int i; | |
437 | const char *pam_user; | |
438 | const char **ptr_pam_user = &pam_user; | |
439 | ||
440 | pam_get_item(sshpam_handle, PAM_USER, | |
441 | (sshpam_const void **)ptr_pam_user); | |
442 | environ[0] = NULL; | |
443 | ||
444 | if (sshpam_authctxt != NULL) { | |
445 | setproctitle("%s [pam]", | |
446 | sshpam_authctxt->valid ? pam_user : "unknown"); | |
447 | } | |
448 | #endif | |
449 | ||
450 | sshpam_conv.conv = sshpam_thread_conv; | |
451 | sshpam_conv.appdata_ptr = ctxt; | |
452 | ||
453 | if (sshpam_authctxt == NULL) | |
454 | fatal("%s: PAM authctxt not initialized", __func__); | |
455 | ||
456 | buffer_init(&buffer); | |
457 | sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, | |
458 | (const void *)&sshpam_conv); | |
459 | if (sshpam_err != PAM_SUCCESS) | |
460 | goto auth_fail; | |
461 | sshpam_err = pam_authenticate(sshpam_handle, flags); | |
462 | if (sshpam_err != PAM_SUCCESS) | |
463 | goto auth_fail; | |
464 | ||
465 | if (compat20) { | |
466 | if (!do_pam_account()) { | |
467 | sshpam_err = PAM_ACCT_EXPIRED; | |
468 | goto auth_fail; | |
469 | } | |
470 | if (sshpam_authctxt->force_pwchange) { | |
471 | sshpam_err = pam_chauthtok(sshpam_handle, | |
472 | PAM_CHANGE_EXPIRED_AUTHTOK); | |
473 | if (sshpam_err != PAM_SUCCESS) | |
474 | goto auth_fail; | |
475 | sshpam_password_change_required(0); | |
476 | } | |
477 | } | |
478 | ||
479 | buffer_put_cstring(&buffer, "OK"); | |
480 | ||
481 | #ifndef UNSUPPORTED_POSIX_THREADS_HACK | |
482 | /* Export variables set by do_pam_account */ | |
483 | buffer_put_int(&buffer, sshpam_account_status); | |
484 | buffer_put_int(&buffer, sshpam_authctxt->force_pwchange); | |
485 | ||
486 | /* Export any environment strings set in child */ | |
487 | for(i = 0; environ[i] != NULL; i++) | |
488 | ; /* Count */ | |
489 | buffer_put_int(&buffer, i); | |
490 | for(i = 0; environ[i] != NULL; i++) | |
491 | buffer_put_cstring(&buffer, environ[i]); | |
492 | ||
493 | /* Export any environment strings set by PAM in child */ | |
494 | env_from_pam = pam_getenvlist(sshpam_handle); | |
495 | for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) | |
496 | ; /* Count */ | |
497 | buffer_put_int(&buffer, i); | |
498 | for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) | |
499 | buffer_put_cstring(&buffer, env_from_pam[i]); | |
500 | #endif /* UNSUPPORTED_POSIX_THREADS_HACK */ | |
501 | ||
502 | /* XXX - can't do much about an error here */ | |
503 | ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer); | |
504 | buffer_free(&buffer); | |
505 | pthread_exit(NULL); | |
506 | ||
507 | auth_fail: | |
508 | buffer_put_cstring(&buffer, | |
509 | pam_strerror(sshpam_handle, sshpam_err)); | |
510 | /* XXX - can't do much about an error here */ | |
511 | if (sshpam_err == PAM_ACCT_EXPIRED) | |
512 | ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer); | |
513 | else | |
514 | ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer); | |
515 | buffer_free(&buffer); | |
516 | pthread_exit(NULL); | |
517 | ||
518 | return (NULL); /* Avoid warning for non-pthread case */ | |
519 | } | |
520 | ||
521 | void | |
522 | sshpam_thread_cleanup(void) | |
523 | { | |
524 | struct pam_ctxt *ctxt = cleanup_ctxt; | |
525 | ||
526 | debug3("PAM: %s entering", __func__); | |
527 | if (ctxt != NULL && ctxt->pam_thread != 0) { | |
528 | pthread_cancel(ctxt->pam_thread); | |
529 | pthread_join(ctxt->pam_thread, NULL); | |
530 | close(ctxt->pam_psock); | |
531 | close(ctxt->pam_csock); | |
532 | memset(ctxt, 0, sizeof(*ctxt)); | |
533 | cleanup_ctxt = NULL; | |
534 | } | |
535 | } | |
536 | ||
537 | static int | |
538 | sshpam_null_conv(int n, sshpam_const struct pam_message **msg, | |
539 | struct pam_response **resp, void *data) | |
540 | { | |
541 | debug3("PAM: %s entering, %d messages", __func__, n); | |
542 | return (PAM_CONV_ERR); | |
543 | } | |
544 | ||
545 | static struct pam_conv null_conv = { sshpam_null_conv, NULL }; | |
546 | ||
547 | static int | |
548 | sshpam_store_conv(int n, sshpam_const struct pam_message **msg, | |
549 | struct pam_response **resp, void *data) | |
550 | { | |
551 | struct pam_response *reply; | |
552 | int i; | |
553 | size_t len; | |
554 | ||
555 | debug3("PAM: %s called with %d messages", __func__, n); | |
556 | *resp = NULL; | |
557 | ||
558 | if (n <= 0 || n > PAM_MAX_NUM_MSG) | |
559 | return (PAM_CONV_ERR); | |
560 | ||
561 | if ((reply = calloc(n, sizeof(*reply))) == NULL) | |
562 | return (PAM_CONV_ERR); | |
563 | ||
564 | for (i = 0; i < n; ++i) { | |
565 | switch (PAM_MSG_MEMBER(msg, i, msg_style)) { | |
566 | case PAM_ERROR_MSG: | |
567 | case PAM_TEXT_INFO: | |
568 | len = strlen(PAM_MSG_MEMBER(msg, i, msg)); | |
569 | buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len); | |
570 | buffer_append(&loginmsg, "\n", 1 ); | |
571 | reply[i].resp_retcode = PAM_SUCCESS; | |
572 | break; | |
573 | default: | |
574 | goto fail; | |
575 | } | |
576 | } | |
577 | *resp = reply; | |
578 | return (PAM_SUCCESS); | |
579 | ||
580 | fail: | |
581 | for(i = 0; i < n; i++) { | |
582 | if (reply[i].resp != NULL) | |
583 | xfree(reply[i].resp); | |
584 | } | |
585 | xfree(reply); | |
586 | return (PAM_CONV_ERR); | |
587 | } | |
588 | ||
589 | static struct pam_conv store_conv = { sshpam_store_conv, NULL }; | |
590 | ||
591 | void | |
592 | sshpam_cleanup(void) | |
593 | { | |
594 | debug("PAM: cleanup"); | |
595 | if (sshpam_handle == NULL) | |
596 | return; | |
597 | pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv); | |
598 | if (sshpam_cred_established) { | |
599 | pam_setcred(sshpam_handle, PAM_DELETE_CRED); | |
600 | sshpam_cred_established = 0; | |
601 | } | |
602 | if (sshpam_session_open) { | |
603 | pam_close_session(sshpam_handle, PAM_SILENT); | |
604 | sshpam_session_open = 0; | |
605 | } | |
606 | sshpam_authenticated = 0; | |
607 | pam_end(sshpam_handle, sshpam_err); | |
608 | sshpam_handle = NULL; | |
609 | } | |
610 | ||
611 | static int | |
612 | sshpam_init(Authctxt *authctxt) | |
613 | { | |
614 | extern char *__progname; | |
615 | const char *pam_rhost, *pam_user, *user = authctxt->user; | |
616 | const char **ptr_pam_user = &pam_user; | |
617 | ||
618 | if (sshpam_handle != NULL) { | |
619 | /* We already have a PAM context; check if the user matches */ | |
620 | sshpam_err = pam_get_item(sshpam_handle, | |
621 | PAM_USER, (sshpam_const void **)ptr_pam_user); | |
622 | if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0) | |
623 | return (0); | |
624 | pam_end(sshpam_handle, sshpam_err); | |
625 | sshpam_handle = NULL; | |
626 | } | |
627 | debug("PAM: initializing for \"%s\"", user); | |
628 | sshpam_err = | |
629 | pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle); | |
630 | sshpam_authctxt = authctxt; | |
631 | ||
632 | if (sshpam_err != PAM_SUCCESS) { | |
633 | pam_end(sshpam_handle, sshpam_err); | |
634 | sshpam_handle = NULL; | |
635 | return (-1); | |
636 | } | |
637 | pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns); | |
638 | debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost); | |
639 | sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost); | |
640 | if (sshpam_err != PAM_SUCCESS) { | |
641 | pam_end(sshpam_handle, sshpam_err); | |
642 | sshpam_handle = NULL; | |
643 | return (-1); | |
644 | } | |
645 | #ifdef PAM_TTY_KLUDGE | |
646 | /* | |
647 | * Some silly PAM modules (e.g. pam_time) require a TTY to operate. | |
648 | * sshd doesn't set the tty until too late in the auth process and | |
649 | * may not even set one (for tty-less connections) | |
650 | */ | |
651 | debug("PAM: setting PAM_TTY to \"ssh\""); | |
652 | sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh"); | |
653 | if (sshpam_err != PAM_SUCCESS) { | |
654 | pam_end(sshpam_handle, sshpam_err); | |
655 | sshpam_handle = NULL; | |
656 | return (-1); | |
657 | } | |
658 | #endif | |
659 | return (0); | |
660 | } | |
661 | ||
662 | static void * | |
663 | sshpam_init_ctx(Authctxt *authctxt) | |
664 | { | |
665 | struct pam_ctxt *ctxt; | |
666 | int socks[2]; | |
667 | ||
668 | debug3("PAM: %s entering", __func__); | |
669 | /* | |
670 | * Refuse to start if we don't have PAM enabled or do_pam_account | |
671 | * has previously failed. | |
672 | */ | |
673 | if (!options.use_pam || sshpam_account_status == 0) | |
674 | return NULL; | |
675 | ||
676 | /* Initialize PAM */ | |
677 | if (sshpam_init(authctxt) == -1) { | |
678 | error("PAM: initialization failed"); | |
679 | return (NULL); | |
680 | } | |
681 | ||
682 | ctxt = xmalloc(sizeof *ctxt); | |
683 | memset(ctxt, 0, sizeof(*ctxt)); | |
684 | ||
685 | /* Start the authentication thread */ | |
686 | if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) { | |
687 | error("PAM: failed create sockets: %s", strerror(errno)); | |
688 | xfree(ctxt); | |
689 | return (NULL); | |
690 | } | |
691 | ctxt->pam_psock = socks[0]; | |
692 | ctxt->pam_csock = socks[1]; | |
693 | if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) { | |
694 | error("PAM: failed to start authentication thread: %s", | |
695 | strerror(errno)); | |
696 | close(socks[0]); | |
697 | close(socks[1]); | |
698 | xfree(ctxt); | |
699 | return (NULL); | |
700 | } | |
701 | cleanup_ctxt = ctxt; | |
702 | return (ctxt); | |
703 | } | |
704 | ||
705 | static int | |
706 | sshpam_query(void *ctx, char **name, char **info, | |
707 | u_int *num, char ***prompts, u_int **echo_on) | |
708 | { | |
709 | Buffer buffer; | |
710 | struct pam_ctxt *ctxt = ctx; | |
711 | size_t plen; | |
712 | u_char type; | |
713 | char *msg; | |
714 | size_t len, mlen; | |
715 | ||
716 | debug3("PAM: %s entering", __func__); | |
717 | buffer_init(&buffer); | |
718 | *name = xstrdup(""); | |
719 | *info = xstrdup(""); | |
720 | *prompts = xmalloc(sizeof(char *)); | |
721 | **prompts = NULL; | |
722 | plen = 0; | |
723 | *echo_on = xmalloc(sizeof(u_int)); | |
724 | while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) { | |
725 | type = buffer_get_char(&buffer); | |
726 | msg = buffer_get_string(&buffer, NULL); | |
727 | mlen = strlen(msg); | |
728 | switch (type) { | |
729 | case PAM_PROMPT_ECHO_ON: | |
730 | case PAM_PROMPT_ECHO_OFF: | |
731 | *num = 1; | |
732 | len = plen + mlen + 1; | |
733 | **prompts = xrealloc(**prompts, 1, len); | |
734 | strlcpy(**prompts + plen, msg, len - plen); | |
735 | plen += mlen; | |
736 | **echo_on = (type == PAM_PROMPT_ECHO_ON); | |
737 | xfree(msg); | |
738 | return (0); | |
739 | case PAM_ERROR_MSG: | |
740 | case PAM_TEXT_INFO: | |
741 | /* accumulate messages */ | |
742 | len = plen + mlen + 2; | |
743 | **prompts = xrealloc(**prompts, 1, len); | |
744 | strlcpy(**prompts + plen, msg, len - plen); | |
745 | plen += mlen; | |
746 | strlcat(**prompts + plen, "\n", len - plen); | |
747 | plen++; | |
748 | xfree(msg); | |
749 | break; | |
750 | case PAM_ACCT_EXPIRED: | |
751 | sshpam_account_status = 0; | |
752 | /* FALLTHROUGH */ | |
753 | case PAM_AUTH_ERR: | |
754 | debug3("PAM: %s", pam_strerror(sshpam_handle, type)); | |
755 | if (**prompts != NULL && strlen(**prompts) != 0) { | |
756 | *info = **prompts; | |
757 | **prompts = NULL; | |
758 | *num = 0; | |
759 | **echo_on = 0; | |
760 | ctxt->pam_done = -1; | |
761 | xfree(msg); | |
762 | return 0; | |
763 | } | |
764 | /* FALLTHROUGH */ | |
765 | case PAM_SUCCESS: | |
766 | if (**prompts != NULL) { | |
767 | /* drain any accumulated messages */ | |
768 | debug("PAM: %s", **prompts); | |
769 | buffer_append(&loginmsg, **prompts, | |
770 | strlen(**prompts)); | |
771 | xfree(**prompts); | |
772 | **prompts = NULL; | |
773 | } | |
774 | if (type == PAM_SUCCESS) { | |
775 | if (!sshpam_authctxt->valid || | |
776 | (sshpam_authctxt->pw->pw_uid == 0 && | |
777 | options.permit_root_login != PERMIT_YES)) | |
778 | fatal("Internal error: PAM auth " | |
779 | "succeeded when it should have " | |
780 | "failed"); | |
781 | import_environments(&buffer); | |
782 | *num = 0; | |
783 | **echo_on = 0; | |
784 | ctxt->pam_done = 1; | |
785 | xfree(msg); | |
786 | return (0); | |
787 | } | |
788 | error("PAM: %s for %s%.100s from %.100s", msg, | |
789 | sshpam_authctxt->valid ? "" : "illegal user ", | |
790 | sshpam_authctxt->user, | |
791 | get_remote_name_or_ip(utmp_len, options.use_dns)); | |
792 | /* FALLTHROUGH */ | |
793 | default: | |
794 | *num = 0; | |
795 | **echo_on = 0; | |
796 | xfree(msg); | |
797 | ctxt->pam_done = -1; | |
798 | return (-1); | |
799 | } | |
800 | } | |
801 | return (-1); | |
802 | } | |
803 | ||
804 | /* XXX - see also comment in auth-chall.c:verify_response */ | |
805 | static int | |
806 | sshpam_respond(void *ctx, u_int num, char **resp) | |
807 | { | |
808 | Buffer buffer; | |
809 | struct pam_ctxt *ctxt = ctx; | |
810 | ||
811 | debug2("PAM: %s entering, %u responses", __func__, num); | |
812 | switch (ctxt->pam_done) { | |
813 | case 1: | |
814 | sshpam_authenticated = 1; | |
815 | return (0); | |
816 | case 0: | |
817 | break; | |
818 | default: | |
819 | return (-1); | |
820 | } | |
821 | if (num != 1) { | |
822 | error("PAM: expected one response, got %u", num); | |
823 | return (-1); | |
824 | } | |
825 | buffer_init(&buffer); | |
826 | if (sshpam_authctxt->valid && | |
827 | (sshpam_authctxt->pw->pw_uid != 0 || | |
828 | options.permit_root_login == PERMIT_YES)) | |
829 | buffer_put_cstring(&buffer, *resp); | |
830 | else | |
831 | buffer_put_cstring(&buffer, badpw); | |
832 | if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) { | |
833 | buffer_free(&buffer); | |
834 | return (-1); | |
835 | } | |
836 | buffer_free(&buffer); | |
837 | return (1); | |
838 | } | |
839 | ||
840 | static void | |
841 | sshpam_free_ctx(void *ctxtp) | |
842 | { | |
843 | struct pam_ctxt *ctxt = ctxtp; | |
844 | ||
845 | debug3("PAM: %s entering", __func__); | |
846 | sshpam_thread_cleanup(); | |
847 | xfree(ctxt); | |
848 | /* | |
849 | * We don't call sshpam_cleanup() here because we may need the PAM | |
850 | * handle at a later stage, e.g. when setting up a session. It's | |
851 | * still on the cleanup list, so pam_end() *will* be called before | |
852 | * the server process terminates. | |
853 | */ | |
854 | } | |
855 | ||
856 | KbdintDevice sshpam_device = { | |
857 | "pam", | |
858 | sshpam_init_ctx, | |
859 | sshpam_query, | |
860 | sshpam_respond, | |
861 | sshpam_free_ctx | |
862 | }; | |
863 | ||
864 | KbdintDevice mm_sshpam_device = { | |
865 | "pam", | |
866 | mm_sshpam_init_ctx, | |
867 | mm_sshpam_query, | |
868 | mm_sshpam_respond, | |
869 | mm_sshpam_free_ctx | |
870 | }; | |
871 | ||
872 | /* | |
873 | * This replaces auth-pam.c | |
874 | */ | |
875 | void | |
876 | start_pam(Authctxt *authctxt) | |
877 | { | |
878 | if (!options.use_pam) | |
879 | fatal("PAM: initialisation requested when UsePAM=no"); | |
880 | ||
881 | if (sshpam_init(authctxt) == -1) | |
882 | fatal("PAM: initialisation failed"); | |
883 | } | |
884 | ||
885 | void | |
886 | finish_pam(void) | |
887 | { | |
888 | sshpam_cleanup(); | |
889 | } | |
890 | ||
891 | u_int | |
892 | do_pam_account(void) | |
893 | { | |
894 | debug("%s: called", __func__); | |
895 | if (sshpam_account_status != -1) | |
896 | return (sshpam_account_status); | |
897 | ||
898 | sshpam_err = pam_acct_mgmt(sshpam_handle, 0); | |
899 | debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err, | |
900 | pam_strerror(sshpam_handle, sshpam_err)); | |
901 | ||
902 | if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) { | |
903 | sshpam_account_status = 0; | |
904 | return (sshpam_account_status); | |
905 | } | |
906 | ||
907 | if (sshpam_err == PAM_NEW_AUTHTOK_REQD) | |
908 | sshpam_password_change_required(1); | |
909 | ||
910 | sshpam_account_status = 1; | |
911 | return (sshpam_account_status); | |
912 | } | |
913 | ||
914 | void | |
915 | do_pam_set_tty(const char *tty) | |
916 | { | |
917 | if (tty != NULL) { | |
918 | debug("PAM: setting PAM_TTY to \"%s\"", tty); | |
919 | sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty); | |
920 | if (sshpam_err != PAM_SUCCESS) | |
921 | fatal("PAM: failed to set PAM_TTY: %s", | |
922 | pam_strerror(sshpam_handle, sshpam_err)); | |
923 | } | |
924 | } | |
925 | ||
926 | void | |
927 | do_pam_setcred(int init) | |
928 | { | |
929 | sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, | |
930 | (const void *)&store_conv); | |
931 | if (sshpam_err != PAM_SUCCESS) | |
932 | fatal("PAM: failed to set PAM_CONV: %s", | |
933 | pam_strerror(sshpam_handle, sshpam_err)); | |
934 | if (init) { | |
935 | debug("PAM: establishing credentials"); | |
936 | sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED); | |
937 | } else { | |
938 | debug("PAM: reinitializing credentials"); | |
939 | sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED); | |
940 | } | |
941 | if (sshpam_err == PAM_SUCCESS) { | |
942 | sshpam_cred_established = 1; | |
943 | return; | |
944 | } | |
945 | if (sshpam_authenticated) | |
946 | fatal("PAM: pam_setcred(): %s", | |
947 | pam_strerror(sshpam_handle, sshpam_err)); | |
948 | else | |
949 | debug("PAM: pam_setcred(): %s", | |
950 | pam_strerror(sshpam_handle, sshpam_err)); | |
951 | } | |
952 | ||
953 | static int | |
954 | sshpam_tty_conv(int n, sshpam_const struct pam_message **msg, | |
955 | struct pam_response **resp, void *data) | |
956 | { | |
957 | char input[PAM_MAX_MSG_SIZE]; | |
958 | struct pam_response *reply; | |
959 | int i; | |
960 | ||
961 | debug3("PAM: %s called with %d messages", __func__, n); | |
962 | ||
963 | *resp = NULL; | |
964 | ||
965 | if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO)) | |
966 | return (PAM_CONV_ERR); | |
967 | ||
968 | if ((reply = calloc(n, sizeof(*reply))) == NULL) | |
969 | return (PAM_CONV_ERR); | |
970 | ||
971 | for (i = 0; i < n; ++i) { | |
972 | switch (PAM_MSG_MEMBER(msg, i, msg_style)) { | |
973 | case PAM_PROMPT_ECHO_OFF: | |
974 | reply[i].resp = | |
975 | read_passphrase(PAM_MSG_MEMBER(msg, i, msg), | |
976 | RP_ALLOW_STDIN); | |
977 | reply[i].resp_retcode = PAM_SUCCESS; | |
978 | break; | |
979 | case PAM_PROMPT_ECHO_ON: | |
980 | fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg)); | |
981 | fgets(input, sizeof input, stdin); | |
982 | if ((reply[i].resp = strdup(input)) == NULL) | |
983 | goto fail; | |
984 | reply[i].resp_retcode = PAM_SUCCESS; | |
985 | break; | |
986 | case PAM_ERROR_MSG: | |
987 | case PAM_TEXT_INFO: | |
988 | fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg)); | |
989 | reply[i].resp_retcode = PAM_SUCCESS; | |
990 | break; | |
991 | default: | |
992 | goto fail; | |
993 | } | |
994 | } | |
995 | *resp = reply; | |
996 | return (PAM_SUCCESS); | |
997 | ||
998 | fail: | |
999 | for(i = 0; i < n; i++) { | |
1000 | if (reply[i].resp != NULL) | |
1001 | xfree(reply[i].resp); | |
1002 | } | |
1003 | xfree(reply); | |
1004 | return (PAM_CONV_ERR); | |
1005 | } | |
1006 | ||
1007 | static struct pam_conv tty_conv = { sshpam_tty_conv, NULL }; | |
1008 | ||
1009 | /* | |
1010 | * XXX this should be done in the authentication phase, but ssh1 doesn't | |
1011 | * support that | |
1012 | */ | |
1013 | void | |
1014 | do_pam_chauthtok(void) | |
1015 | { | |
1016 | if (use_privsep) | |
1017 | fatal("Password expired (unable to change with privsep)"); | |
1018 | sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, | |
1019 | (const void *)&tty_conv); | |
1020 | if (sshpam_err != PAM_SUCCESS) | |
1021 | fatal("PAM: failed to set PAM_CONV: %s", | |
1022 | pam_strerror(sshpam_handle, sshpam_err)); | |
1023 | debug("PAM: changing password"); | |
1024 | sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK); | |
1025 | if (sshpam_err != PAM_SUCCESS) | |
1026 | fatal("PAM: pam_chauthtok(): %s", | |
1027 | pam_strerror(sshpam_handle, sshpam_err)); | |
1028 | } | |
1029 | ||
1030 | void | |
1031 | do_pam_session(void) | |
1032 | { | |
1033 | debug3("PAM: opening session"); | |
1034 | sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, | |
1035 | (const void *)&store_conv); | |
1036 | if (sshpam_err != PAM_SUCCESS) | |
1037 | fatal("PAM: failed to set PAM_CONV: %s", | |
1038 | pam_strerror(sshpam_handle, sshpam_err)); | |
1039 | sshpam_err = pam_open_session(sshpam_handle, 0); | |
1040 | if (sshpam_err == PAM_SUCCESS) | |
1041 | sshpam_session_open = 1; | |
1042 | else { | |
1043 | sshpam_session_open = 0; | |
1044 | disable_forwarding(); | |
1045 | error("PAM: pam_open_session(): %s", | |
1046 | pam_strerror(sshpam_handle, sshpam_err)); | |
1047 | } | |
1048 | ||
1049 | } | |
1050 | ||
1051 | int | |
1052 | is_pam_session_open(void) | |
1053 | { | |
1054 | return sshpam_session_open; | |
1055 | } | |
1056 | ||
1057 | /* | |
1058 | * Set a PAM environment string. We need to do this so that the session | |
1059 | * modules can handle things like Kerberos/GSI credentials that appear | |
1060 | * during the ssh authentication process. | |
1061 | */ | |
1062 | int | |
1063 | do_pam_putenv(char *name, char *value) | |
1064 | { | |
1065 | int ret = 1; | |
1066 | #ifdef HAVE_PAM_PUTENV | |
1067 | char *compound; | |
1068 | size_t len; | |
1069 | ||
1070 | len = strlen(name) + strlen(value) + 2; | |
1071 | compound = xmalloc(len); | |
1072 | ||
1073 | snprintf(compound, len, "%s=%s", name, value); | |
1074 | ret = pam_putenv(sshpam_handle, compound); | |
1075 | xfree(compound); | |
1076 | #endif | |
1077 | ||
1078 | return (ret); | |
1079 | } | |
1080 | ||
1081 | char ** | |
1082 | fetch_pam_child_environment(void) | |
1083 | { | |
1084 | return sshpam_env; | |
1085 | } | |
1086 | ||
1087 | char ** | |
1088 | fetch_pam_environment(void) | |
1089 | { | |
1090 | return (pam_getenvlist(sshpam_handle)); | |
1091 | } | |
1092 | ||
1093 | void | |
1094 | free_pam_environment(char **env) | |
1095 | { | |
1096 | char **envp; | |
1097 | ||
1098 | if (env == NULL) | |
1099 | return; | |
1100 | ||
1101 | for (envp = env; *envp; envp++) | |
1102 | xfree(*envp); | |
1103 | xfree(env); | |
1104 | } | |
1105 | ||
1106 | /* | |
1107 | * "Blind" conversation function for password authentication. Assumes that | |
1108 | * echo-off prompts are for the password and stores messages for later | |
1109 | * display. | |
1110 | */ | |
1111 | static int | |
1112 | sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg, | |
1113 | struct pam_response **resp, void *data) | |
1114 | { | |
1115 | struct pam_response *reply; | |
1116 | int i; | |
1117 | size_t len; | |
1118 | ||
1119 | debug3("PAM: %s called with %d messages", __func__, n); | |
1120 | ||
1121 | *resp = NULL; | |
1122 | ||
1123 | if (n <= 0 || n > PAM_MAX_NUM_MSG) | |
1124 | return (PAM_CONV_ERR); | |
1125 | ||
1126 | if ((reply = malloc(n * sizeof(*reply))) == NULL) | |
1127 | return (PAM_CONV_ERR); | |
1128 | memset(reply, 0, n * sizeof(*reply)); | |
1129 | ||
1130 | for (i = 0; i < n; ++i) { | |
1131 | switch (PAM_MSG_MEMBER(msg, i, msg_style)) { | |
1132 | case PAM_PROMPT_ECHO_OFF: | |
1133 | if (sshpam_password == NULL) | |
1134 | goto fail; | |
1135 | if ((reply[i].resp = strdup(sshpam_password)) == NULL) | |
1136 | goto fail; | |
1137 | reply[i].resp_retcode = PAM_SUCCESS; | |
1138 | break; | |
1139 | case PAM_ERROR_MSG: | |
1140 | case PAM_TEXT_INFO: | |
1141 | len = strlen(PAM_MSG_MEMBER(msg, i, msg)); | |
1142 | if (len > 0) { | |
1143 | buffer_append(&loginmsg, | |
1144 | PAM_MSG_MEMBER(msg, i, msg), len); | |
1145 | buffer_append(&loginmsg, "\n", 1); | |
1146 | } | |
1147 | if ((reply[i].resp = strdup("")) == NULL) | |
1148 | goto fail; | |
1149 | reply[i].resp_retcode = PAM_SUCCESS; | |
1150 | break; | |
1151 | default: | |
1152 | goto fail; | |
1153 | } | |
1154 | } | |
1155 | *resp = reply; | |
1156 | return (PAM_SUCCESS); | |
1157 | ||
1158 | fail: | |
1159 | for(i = 0; i < n; i++) { | |
1160 | if (reply[i].resp != NULL) | |
1161 | xfree(reply[i].resp); | |
1162 | } | |
1163 | xfree(reply); | |
1164 | return (PAM_CONV_ERR); | |
1165 | } | |
1166 | ||
1167 | static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL }; | |
1168 | ||
1169 | /* | |
1170 | * Attempt password authentication via PAM | |
1171 | */ | |
1172 | int | |
1173 | sshpam_auth_passwd(Authctxt *authctxt, const char *password) | |
1174 | { | |
1175 | int flags = (options.permit_empty_passwd == 0 ? | |
1176 | PAM_DISALLOW_NULL_AUTHTOK : 0); | |
1177 | ||
1178 | if (!options.use_pam || sshpam_handle == NULL) | |
1179 | fatal("PAM: %s called when PAM disabled or failed to " | |
1180 | "initialise.", __func__); | |
1181 | ||
1182 | sshpam_password = password; | |
1183 | sshpam_authctxt = authctxt; | |
1184 | ||
1185 | /* | |
1186 | * If the user logging in is invalid, or is root but is not permitted | |
1187 | * by PermitRootLogin, use an invalid password to prevent leaking | |
1188 | * information via timing (eg if the PAM config has a delay on fail). | |
1189 | */ | |
1190 | if (!authctxt->valid || (authctxt->pw->pw_uid == 0 && | |
1191 | options.permit_root_login != PERMIT_YES)) | |
1192 | sshpam_password = badpw; | |
1193 | ||
1194 | sshpam_err = pam_set_item(sshpam_handle, PAM_CONV, | |
1195 | (const void *)&passwd_conv); | |
1196 | if (sshpam_err != PAM_SUCCESS) | |
1197 | fatal("PAM: %s: failed to set PAM_CONV: %s", __func__, | |
1198 | pam_strerror(sshpam_handle, sshpam_err)); | |
1199 | ||
1200 | sshpam_err = pam_authenticate(sshpam_handle, flags); | |
1201 | sshpam_password = NULL; | |
1202 | if (sshpam_err == PAM_SUCCESS && authctxt->valid) { | |
1203 | debug("PAM: password authentication accepted for %.100s", | |
1204 | authctxt->user); | |
1205 | return 1; | |
1206 | } else { | |
1207 | debug("PAM: password authentication failed for %.100s: %s", | |
1208 | authctxt->valid ? authctxt->user : "an illegal user", | |
1209 | pam_strerror(sshpam_handle, sshpam_err)); | |
1210 | return 0; | |
1211 | } | |
1212 | } | |
1213 | #endif /* USE_PAM */ |