2 * Copyright (c) 2002 Networks Associates Technology, Inc.
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * NAI Labs, the Security Research Division of Network Associates, Inc.
7 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
8 * DARPA CHATS research program.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 /* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
37 #include <security/pam_appl.h>
45 #include "monitor_wrap.h"
52 #include "auth-options.h"
54 extern ServerOptions options;
58 #ifdef USE_POSIX_THREADS
61 * Avoid namespace clash when *not* using pthreads for systems *with*
62 * pthreads, which unconditionally define pthread_t via sys/types.h
65 typedef pthread_t sp_pthread_t;
68 * Simulate threads with processes.
70 typedef pid_t sp_pthread_t;
73 pthread_exit(void *value __unused)
79 pthread_create(sp_pthread_t *thread, const void *attr __unused,
80 void *(*thread_start)(void *), void *arg)
84 switch ((pid = fork())) {
86 error("fork(): %s", strerror(errno));
98 pthread_cancel(sp_pthread_t thread)
100 return (kill(thread, SIGTERM));
104 pthread_join(sp_pthread_t thread, void **value __unused)
108 waitpid(thread, &status, 0);
114 static pam_handle_t *sshpam_handle;
115 static int sshpam_err;
116 static int sshpam_authenticated;
117 static int sshpam_new_authtok_reqd;
118 static int sshpam_session_open;
119 static int sshpam_cred_established;
122 sp_pthread_t pam_thread;
128 static void sshpam_free_ctx(void *);
131 * Conversation function for authentication thread.
134 sshpam_thread_conv(int n, const struct pam_message **msg,
135 struct pam_response **resp, void *data)
138 struct pam_ctxt *ctxt;
142 if (n <= 0 || n > PAM_MAX_NUM_MSG)
143 return (PAM_CONV_ERR);
144 *resp = xmalloc(n * sizeof **resp);
145 buffer_init(&buffer);
146 for (i = 0; i < n; ++i) {
147 resp[i]->resp_retcode = 0;
148 resp[i]->resp = NULL;
149 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
150 case PAM_PROMPT_ECHO_OFF:
151 buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
152 ssh_msg_send(ctxt->pam_csock,
153 PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
154 ssh_msg_recv(ctxt->pam_csock, &buffer);
155 if (buffer_get_char(&buffer) != PAM_AUTHTOK)
157 resp[i]->resp = buffer_get_string(&buffer, NULL);
159 case PAM_PROMPT_ECHO_ON:
160 buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
161 ssh_msg_send(ctxt->pam_csock,
162 PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
163 ssh_msg_recv(ctxt->pam_csock, &buffer);
164 if (buffer_get_char(&buffer) != PAM_AUTHTOK)
166 resp[i]->resp = buffer_get_string(&buffer, NULL);
169 buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
170 ssh_msg_send(ctxt->pam_csock,
171 PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
174 buffer_put_cstring(&buffer, PAM_MSG_MEMBER(msg, i, msg));
175 ssh_msg_send(ctxt->pam_csock,
176 PAM_MSG_MEMBER(msg, i, msg_style), &buffer);
181 buffer_clear(&buffer);
183 buffer_free(&buffer);
184 return (PAM_SUCCESS);
190 buffer_free(&buffer);
191 return (PAM_CONV_ERR);
195 * Authentication thread.
198 sshpam_thread(void *ctxtp)
200 struct pam_ctxt *ctxt = ctxtp;
202 struct pam_conv sshpam_conv;
203 #ifndef USE_POSIX_THREADS
204 const char *pam_user;
206 pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
207 setproctitle("%s [pam]", pam_user);
210 sshpam_conv.conv = sshpam_thread_conv;
211 sshpam_conv.appdata_ptr = ctxt;
213 buffer_init(&buffer);
214 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
215 (const void *)&sshpam_conv);
216 if (sshpam_err != PAM_SUCCESS)
218 sshpam_err = pam_authenticate(sshpam_handle, 0);
219 if (sshpam_err != PAM_SUCCESS)
221 buffer_put_cstring(&buffer, "OK");
222 ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
223 buffer_free(&buffer);
227 buffer_put_cstring(&buffer,
228 pam_strerror(sshpam_handle, sshpam_err));
229 ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
230 buffer_free(&buffer);
233 return (NULL); /* Avoid warning for non-pthread case */
237 sshpam_thread_cleanup(void *ctxtp)
239 struct pam_ctxt *ctxt = ctxtp;
241 pthread_cancel(ctxt->pam_thread);
242 pthread_join(ctxt->pam_thread, NULL);
243 close(ctxt->pam_psock);
244 close(ctxt->pam_csock);
248 sshpam_null_conv(int n, const struct pam_message **msg,
249 struct pam_response **resp, void *data)
251 return (PAM_CONV_ERR);
254 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
257 sshpam_cleanup(void *arg)
260 debug("PAM: cleanup");
261 pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
262 if (sshpam_cred_established) {
263 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
264 sshpam_cred_established = 0;
266 if (sshpam_session_open) {
267 pam_close_session(sshpam_handle, PAM_SILENT);
268 sshpam_session_open = 0;
270 sshpam_authenticated = sshpam_new_authtok_reqd = 0;
271 pam_end(sshpam_handle, sshpam_err);
272 sshpam_handle = NULL;
276 sshpam_init(const char *user)
278 extern u_int utmp_len;
279 extern char *__progname;
280 const char *pam_rhost, *pam_user;
282 if (sshpam_handle != NULL) {
283 /* We already have a PAM context; check if the user matches */
284 sshpam_err = pam_get_item(sshpam_handle,
285 PAM_USER, (const void **)&pam_user);
286 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
288 fatal_remove_cleanup(sshpam_cleanup, NULL);
289 pam_end(sshpam_handle, sshpam_err);
290 sshpam_handle = NULL;
292 debug("PAM: initializing for \"%s\"", user);
294 pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
295 if (sshpam_err != PAM_SUCCESS) {
296 pam_end(sshpam_handle, sshpam_err);
297 sshpam_handle = NULL;
300 pam_rhost = get_remote_name_or_ip(utmp_len, options.use_dns);
301 debug("PAM: setting PAM_RHOST to \"%s\"", pam_rhost);
302 sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST, pam_rhost);
303 if (sshpam_err != PAM_SUCCESS) {
304 pam_end(sshpam_handle, sshpam_err);
305 sshpam_handle = NULL;
308 #ifdef PAM_TTY_KLUDGE
310 * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
311 * sshd doesn't set the tty until too late in the auth process and
312 * may not even set one (for tty-less connections)
314 debug("PAM: setting PAM_TTY to \"ssh\"");
315 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
316 if (sshpam_err != PAM_SUCCESS) {
317 pam_end(sshpam_handle, sshpam_err);
318 sshpam_handle = NULL;
322 fatal_add_cleanup(sshpam_cleanup, NULL);
327 sshpam_init_ctx(Authctxt *authctxt)
329 struct pam_ctxt *ctxt;
332 /* Refuse to start if we don't have PAM enabled */
333 if (!options.use_pam)
337 if (sshpam_init(authctxt->user) == -1) {
338 error("PAM: initialization failed");
342 ctxt = xmalloc(sizeof *ctxt);
345 /* Start the authentication thread */
346 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
347 error("PAM: failed create sockets: %s", strerror(errno));
351 ctxt->pam_psock = socks[0];
352 ctxt->pam_csock = socks[1];
353 if (pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt) == -1) {
354 error("PAM: failed to start authentication thread: %s",
361 fatal_add_cleanup(sshpam_thread_cleanup, ctxt);
366 sshpam_query(void *ctx, char **name, char **info,
367 u_int *num, char ***prompts, u_int **echo_on)
370 struct pam_ctxt *ctxt = ctx;
376 buffer_init(&buffer);
379 *prompts = xmalloc(sizeof(char *));
382 *echo_on = xmalloc(sizeof(u_int));
383 while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
384 type = buffer_get_char(&buffer);
385 msg = buffer_get_string(&buffer, NULL);
387 case PAM_PROMPT_ECHO_ON:
388 case PAM_PROMPT_ECHO_OFF:
390 len = plen + strlen(msg) + 1;
391 **prompts = xrealloc(**prompts, len);
392 plen += snprintf(**prompts + plen, len, "%s", msg);
393 **echo_on = (type == PAM_PROMPT_ECHO_ON);
398 /* accumulate messages */
399 len = plen + strlen(msg) + 1;
400 **prompts = xrealloc(**prompts, len);
401 plen += snprintf(**prompts + plen, len, "%s", msg);
406 if (**prompts != NULL) {
407 /* drain any accumulated messages */
408 #if 0 /* XXX - not compatible with privsep */
409 packet_start(SSH2_MSG_USERAUTH_BANNER);
410 packet_put_cstring(**prompts);
411 packet_put_cstring("");
418 if (type == PAM_SUCCESS) {
425 error("PAM: %s", msg);
437 /* XXX - see also comment in auth-chall.c:verify_response */
439 sshpam_respond(void *ctx, u_int num, char **resp)
442 struct pam_ctxt *ctxt = ctx;
444 debug2("PAM: %s", __func__);
445 switch (ctxt->pam_done) {
447 sshpam_authenticated = 1;
455 error("PAM: expected one response, got %u", num);
458 buffer_init(&buffer);
459 buffer_put_cstring(&buffer, *resp);
460 ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer);
461 buffer_free(&buffer);
466 sshpam_free_ctx(void *ctxtp)
468 struct pam_ctxt *ctxt = ctxtp;
470 fatal_remove_cleanup(sshpam_thread_cleanup, ctxt);
471 sshpam_thread_cleanup(ctxtp);
474 * We don't call sshpam_cleanup() here because we may need the PAM
475 * handle at a later stage, e.g. when setting up a session. It's
476 * still on the cleanup list, so pam_end() *will* be called before
477 * the server process terminates.
481 KbdintDevice sshpam_device = {
489 KbdintDevice mm_sshpam_device = {
498 * This replaces auth-pam.c
501 start_pam(const char *user)
503 if (!options.use_pam)
504 fatal("PAM: initialisation requested when UsePAM=no");
506 if (sshpam_init(user) == -1)
507 fatal("PAM: initialisation failed");
513 fatal_remove_cleanup(sshpam_cleanup, NULL);
514 sshpam_cleanup(NULL);
520 sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
521 debug3("%s: pam_acct_mgmt = %d", __func__, sshpam_err);
523 if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD)
526 if (sshpam_err == PAM_NEW_AUTHTOK_REQD) {
527 sshpam_new_authtok_reqd = 1;
529 /* Prevent forwardings until password changed */
530 no_port_forwarding_flag |= 2;
531 no_agent_forwarding_flag |= 2;
532 no_x11_forwarding_flag |= 2;
541 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
542 (const void *)&null_conv);
543 if (sshpam_err != PAM_SUCCESS)
544 fatal("PAM: failed to set PAM_CONV: %s",
545 pam_strerror(sshpam_handle, sshpam_err));
546 sshpam_err = pam_open_session(sshpam_handle, 0);
547 if (sshpam_err != PAM_SUCCESS)
548 fatal("PAM: pam_open_session(): %s",
549 pam_strerror(sshpam_handle, sshpam_err));
550 sshpam_session_open = 1;
554 do_pam_set_tty(const char *tty)
557 debug("PAM: setting PAM_TTY to \"%s\"", tty);
558 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, tty);
559 if (sshpam_err != PAM_SUCCESS)
560 fatal("PAM: failed to set PAM_TTY: %s",
561 pam_strerror(sshpam_handle, sshpam_err));
566 do_pam_setcred(int init)
568 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
569 (const void *)&null_conv);
570 if (sshpam_err != PAM_SUCCESS)
571 fatal("PAM: failed to set PAM_CONV: %s",
572 pam_strerror(sshpam_handle, sshpam_err));
574 debug("PAM: establishing credentials");
575 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
577 debug("PAM: reinitializing credentials");
578 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
580 if (sshpam_err == PAM_SUCCESS) {
581 sshpam_cred_established = 1;
584 if (sshpam_authenticated)
585 fatal("PAM: pam_setcred(): %s",
586 pam_strerror(sshpam_handle, sshpam_err));
588 debug("PAM: pam_setcred(): %s",
589 pam_strerror(sshpam_handle, sshpam_err));
593 is_pam_password_change_required(void)
595 return (sshpam_new_authtok_reqd);
599 pam_chauthtok_conv(int n, const struct pam_message **msg,
600 struct pam_response **resp, void *data)
602 char input[PAM_MAX_MSG_SIZE];
605 if (n <= 0 || n > PAM_MAX_NUM_MSG)
606 return (PAM_CONV_ERR);
607 *resp = xmalloc(n * sizeof **resp);
608 for (i = 0; i < n; ++i) {
609 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
610 case PAM_PROMPT_ECHO_OFF:
612 read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
614 resp[i]->resp_retcode = PAM_SUCCESS;
616 case PAM_PROMPT_ECHO_ON:
617 fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
618 fgets(input, sizeof input, stdin);
619 resp[i]->resp = xstrdup(input);
620 resp[i]->resp_retcode = PAM_SUCCESS;
624 fputs(PAM_MSG_MEMBER(msg, i, msg), stderr);
625 resp[i]->resp_retcode = PAM_SUCCESS;
631 return (PAM_SUCCESS);
637 return (PAM_CONV_ERR);
641 * XXX this should be done in the authentication phase, but ssh1 doesn't
645 do_pam_chauthtok(void)
647 struct pam_conv pam_conv;
649 pam_conv.conv = pam_chauthtok_conv;
650 pam_conv.appdata_ptr = NULL;
653 fatal("Password expired (unable to change with privsep)");
654 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
655 (const void *)&pam_conv);
656 if (sshpam_err != PAM_SUCCESS)
657 fatal("PAM: failed to set PAM_CONV: %s",
658 pam_strerror(sshpam_handle, sshpam_err));
659 debug("PAM: changing password");
660 sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
661 if (sshpam_err != PAM_SUCCESS)
662 fatal("PAM: pam_chauthtok(): %s",
663 pam_strerror(sshpam_handle, sshpam_err));
667 * Set a PAM environment string. We need to do this so that the session
668 * modules can handle things like Kerberos/GSI credentials that appear
669 * during the ssh authentication process.
673 do_pam_putenv(char *name, char *value)
676 #ifdef HAVE_PAM_PUTENV
680 len = strlen(name) + strlen(value) + 2;
681 compound = xmalloc(len);
683 snprintf(compound, len, "%s=%s", name, value);
684 ret = pam_putenv(sshpam_handle, compound);
692 print_pam_messages(void)
698 fetch_pam_environment(void)
700 #ifdef HAVE_PAM_GETENVLIST
701 debug("PAM: retrieving environment");
702 return (pam_getenvlist(sshpam_handle));
709 free_pam_environment(char **env)
716 for (envp = env; *envp; envp++)