xref: /freebsd/crypto/openssh/monitor.c (revision a0ee8cc636cd5c2374ec44ca71226564ea0bca95)
1 /* $OpenBSD: monitor.c,v 1.135 2014/07/15 15:54:14 millert Exp $ */
2 /*
3  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
4  * Copyright 2002 Markus Friedl <markus@openbsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include "includes.h"
29 
30 #include <sys/types.h>
31 #include <sys/param.h>
32 #include <sys/socket.h>
33 #include "openbsd-compat/sys-tree.h"
34 #include <sys/wait.h>
35 
36 #include <errno.h>
37 #include <fcntl.h>
38 #ifdef HAVE_PATHS_H
39 #include <paths.h>
40 #endif
41 #include <pwd.h>
42 #include <signal.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <stdarg.h>
46 #include <stdio.h>
47 #include <unistd.h>
48 #ifdef HAVE_POLL_H
49 #include <poll.h>
50 #else
51 # ifdef HAVE_SYS_POLL_H
52 #  include <sys/poll.h>
53 # endif
54 #endif
55 
56 #ifdef SKEY
57 #include <skey.h>
58 #endif
59 
60 #ifdef WITH_OPENSSL
61 #include <openssl/dh.h>
62 #endif
63 
64 #include "openbsd-compat/sys-queue.h"
65 #include "atomicio.h"
66 #include "xmalloc.h"
67 #include "ssh.h"
68 #include "key.h"
69 #include "buffer.h"
70 #include "hostfile.h"
71 #include "auth.h"
72 #include "cipher.h"
73 #include "kex.h"
74 #include "dh.h"
75 #ifdef TARGET_OS_MAC	/* XXX Broken krb5 headers on Mac */
76 #undef TARGET_OS_MAC
77 #include "zlib.h"
78 #define TARGET_OS_MAC 1
79 #else
80 #include "zlib.h"
81 #endif
82 #include "packet.h"
83 #include "auth-options.h"
84 #include "sshpty.h"
85 #include "channels.h"
86 #include "session.h"
87 #include "sshlogin.h"
88 #include "canohost.h"
89 #include "log.h"
90 #include "misc.h"
91 #include "servconf.h"
92 #include "monitor.h"
93 #include "monitor_mm.h"
94 #ifdef GSSAPI
95 #include "ssh-gss.h"
96 #endif
97 #include "monitor_wrap.h"
98 #include "monitor_fdpass.h"
99 #include "compat.h"
100 #include "ssh2.h"
101 #include "roaming.h"
102 #include "authfd.h"
103 
104 #ifdef GSSAPI
105 static Gssctxt *gsscontext = NULL;
106 #endif
107 
108 /* Imports */
109 extern ServerOptions options;
110 extern u_int utmp_len;
111 extern Newkeys *current_keys[];
112 extern z_stream incoming_stream;
113 extern z_stream outgoing_stream;
114 extern u_char session_id[];
115 extern Buffer auth_debug;
116 extern int auth_debug_init;
117 extern Buffer loginmsg;
118 
119 /* State exported from the child */
120 
121 struct {
122 	z_stream incoming;
123 	z_stream outgoing;
124 	u_char *keyin;
125 	u_int keyinlen;
126 	u_char *keyout;
127 	u_int keyoutlen;
128 	u_char *ivin;
129 	u_int ivinlen;
130 	u_char *ivout;
131 	u_int ivoutlen;
132 	u_char *ssh1key;
133 	u_int ssh1keylen;
134 	int ssh1cipher;
135 	int ssh1protoflags;
136 	u_char *input;
137 	u_int ilen;
138 	u_char *output;
139 	u_int olen;
140 	u_int64_t sent_bytes;
141 	u_int64_t recv_bytes;
142 } child_state;
143 
144 /* Functions on the monitor that answer unprivileged requests */
145 
146 int mm_answer_moduli(int, Buffer *);
147 int mm_answer_sign(int, Buffer *);
148 int mm_answer_pwnamallow(int, Buffer *);
149 int mm_answer_auth2_read_banner(int, Buffer *);
150 int mm_answer_authserv(int, Buffer *);
151 int mm_answer_authpassword(int, Buffer *);
152 int mm_answer_bsdauthquery(int, Buffer *);
153 int mm_answer_bsdauthrespond(int, Buffer *);
154 int mm_answer_skeyquery(int, Buffer *);
155 int mm_answer_skeyrespond(int, Buffer *);
156 int mm_answer_keyallowed(int, Buffer *);
157 int mm_answer_keyverify(int, Buffer *);
158 int mm_answer_pty(int, Buffer *);
159 int mm_answer_pty_cleanup(int, Buffer *);
160 int mm_answer_term(int, Buffer *);
161 int mm_answer_rsa_keyallowed(int, Buffer *);
162 int mm_answer_rsa_challenge(int, Buffer *);
163 int mm_answer_rsa_response(int, Buffer *);
164 int mm_answer_sesskey(int, Buffer *);
165 int mm_answer_sessid(int, Buffer *);
166 
167 #ifdef USE_PAM
168 int mm_answer_pam_start(int, Buffer *);
169 int mm_answer_pam_account(int, Buffer *);
170 int mm_answer_pam_init_ctx(int, Buffer *);
171 int mm_answer_pam_query(int, Buffer *);
172 int mm_answer_pam_respond(int, Buffer *);
173 int mm_answer_pam_free_ctx(int, Buffer *);
174 #endif
175 
176 #ifdef GSSAPI
177 int mm_answer_gss_setup_ctx(int, Buffer *);
178 int mm_answer_gss_accept_ctx(int, Buffer *);
179 int mm_answer_gss_userok(int, Buffer *);
180 int mm_answer_gss_checkmic(int, Buffer *);
181 #endif
182 
183 #ifdef SSH_AUDIT_EVENTS
184 int mm_answer_audit_event(int, Buffer *);
185 int mm_answer_audit_command(int, Buffer *);
186 #endif
187 
188 static int monitor_read_log(struct monitor *);
189 
190 static Authctxt *authctxt;
191 
192 #ifdef WITH_SSH1
193 static BIGNUM *ssh1_challenge = NULL;	/* used for ssh1 rsa auth */
194 #endif
195 
196 /* local state for key verify */
197 static u_char *key_blob = NULL;
198 static u_int key_bloblen = 0;
199 static int key_blobtype = MM_NOKEY;
200 static char *hostbased_cuser = NULL;
201 static char *hostbased_chost = NULL;
202 static char *auth_method = "unknown";
203 static char *auth_submethod = NULL;
204 static u_int session_id2_len = 0;
205 static u_char *session_id2 = NULL;
206 static pid_t monitor_child_pid;
207 
208 struct mon_table {
209 	enum monitor_reqtype type;
210 	int flags;
211 	int (*f)(int, Buffer *);
212 };
213 
214 #define MON_ISAUTH	0x0004	/* Required for Authentication */
215 #define MON_AUTHDECIDE	0x0008	/* Decides Authentication */
216 #define MON_ONCE	0x0010	/* Disable after calling */
217 #define MON_ALOG	0x0020	/* Log auth attempt without authenticating */
218 
219 #define MON_AUTH	(MON_ISAUTH|MON_AUTHDECIDE)
220 
221 #define MON_PERMIT	0x1000	/* Request is permitted */
222 
223 struct mon_table mon_dispatch_proto20[] = {
224 #ifdef WITH_OPENSSL
225     {MONITOR_REQ_MODULI, MON_ONCE, mm_answer_moduli},
226 #endif
227     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
228     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
229     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
230     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
231     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
232 #ifdef USE_PAM
233     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
234     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
235     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
236     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
237     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
238     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
239 #endif
240 #ifdef SSH_AUDIT_EVENTS
241     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
242 #endif
243 #ifdef BSD_AUTH
244     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
245     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
246 #endif
247 #ifdef SKEY
248     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
249     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
250 #endif
251     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH, mm_answer_keyallowed},
252     {MONITOR_REQ_KEYVERIFY, MON_AUTH, mm_answer_keyverify},
253 #ifdef GSSAPI
254     {MONITOR_REQ_GSSSETUP, MON_ISAUTH, mm_answer_gss_setup_ctx},
255     {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx},
256     {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok},
257     {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic},
258 #endif
259     {0, 0, NULL}
260 };
261 
262 struct mon_table mon_dispatch_postauth20[] = {
263 #ifdef WITH_OPENSSL
264     {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
265 #endif
266     {MONITOR_REQ_SIGN, 0, mm_answer_sign},
267     {MONITOR_REQ_PTY, 0, mm_answer_pty},
268     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
269     {MONITOR_REQ_TERM, 0, mm_answer_term},
270 #ifdef SSH_AUDIT_EVENTS
271     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
272     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
273 #endif
274     {0, 0, NULL}
275 };
276 
277 struct mon_table mon_dispatch_proto15[] = {
278 #ifdef WITH_SSH1
279     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
280     {MONITOR_REQ_SESSKEY, MON_ONCE, mm_answer_sesskey},
281     {MONITOR_REQ_SESSID, MON_ONCE, mm_answer_sessid},
282     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
283     {MONITOR_REQ_RSAKEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_rsa_keyallowed},
284     {MONITOR_REQ_KEYALLOWED, MON_ISAUTH|MON_ALOG, mm_answer_keyallowed},
285     {MONITOR_REQ_RSACHALLENGE, MON_ONCE, mm_answer_rsa_challenge},
286     {MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
287 #ifdef BSD_AUTH
288     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
289     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH, mm_answer_bsdauthrespond},
290 #endif
291 #ifdef SKEY
292     {MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
293     {MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
294 #endif
295 #ifdef USE_PAM
296     {MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
297     {MONITOR_REQ_PAM_ACCOUNT, 0, mm_answer_pam_account},
298     {MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
299     {MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
300     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
301     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
302 #endif
303 #ifdef SSH_AUDIT_EVENTS
304     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
305 #endif
306 #endif /* WITH_SSH1 */
307     {0, 0, NULL}
308 };
309 
310 struct mon_table mon_dispatch_postauth15[] = {
311 #ifdef WITH_SSH1
312     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
313     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
314     {MONITOR_REQ_TERM, 0, mm_answer_term},
315 #ifdef SSH_AUDIT_EVENTS
316     {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
317     {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT|MON_ONCE, mm_answer_audit_command},
318 #endif
319 #endif /* WITH_SSH1 */
320     {0, 0, NULL}
321 };
322 
323 struct mon_table *mon_dispatch;
324 
325 /* Specifies if a certain message is allowed at the moment */
326 
327 static void
328 monitor_permit(struct mon_table *ent, enum monitor_reqtype type, int permit)
329 {
330 	while (ent->f != NULL) {
331 		if (ent->type == type) {
332 			ent->flags &= ~MON_PERMIT;
333 			ent->flags |= permit ? MON_PERMIT : 0;
334 			return;
335 		}
336 		ent++;
337 	}
338 }
339 
340 static void
341 monitor_permit_authentications(int permit)
342 {
343 	struct mon_table *ent = mon_dispatch;
344 
345 	while (ent->f != NULL) {
346 		if (ent->flags & MON_AUTH) {
347 			ent->flags &= ~MON_PERMIT;
348 			ent->flags |= permit ? MON_PERMIT : 0;
349 		}
350 		ent++;
351 	}
352 }
353 
354 void
355 monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
356 {
357 	struct mon_table *ent;
358 	int authenticated = 0, partial = 0;
359 
360 	debug3("preauth child monitor started");
361 
362 	close(pmonitor->m_recvfd);
363 	close(pmonitor->m_log_sendfd);
364 	pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
365 
366 	authctxt = _authctxt;
367 	memset(authctxt, 0, sizeof(*authctxt));
368 
369 	authctxt->loginmsg = &loginmsg;
370 
371 	if (compat20) {
372 		mon_dispatch = mon_dispatch_proto20;
373 
374 		/* Permit requests for moduli and signatures */
375 		monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
376 		monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
377 	} else {
378 		mon_dispatch = mon_dispatch_proto15;
379 
380 		monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 1);
381 	}
382 
383 	/* The first few requests do not require asynchronous access */
384 	while (!authenticated) {
385 		partial = 0;
386 		auth_method = "unknown";
387 		auth_submethod = NULL;
388 		authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1);
389 
390 		/* Special handling for multiple required authentications */
391 		if (options.num_auth_methods != 0) {
392 			if (!compat20)
393 				fatal("AuthenticationMethods is not supported"
394 				    "with SSH protocol 1");
395 			if (authenticated &&
396 			    !auth2_update_methods_lists(authctxt,
397 			    auth_method, auth_submethod)) {
398 				debug3("%s: method %s: partial", __func__,
399 				    auth_method);
400 				authenticated = 0;
401 				partial = 1;
402 			}
403 		}
404 
405 		if (authenticated) {
406 			if (!(ent->flags & MON_AUTHDECIDE))
407 				fatal("%s: unexpected authentication from %d",
408 				    __func__, ent->type);
409 			if (authctxt->pw->pw_uid == 0 &&
410 			    !auth_root_allowed(auth_method))
411 				authenticated = 0;
412 #ifdef USE_PAM
413 			/* PAM needs to perform account checks after auth */
414 			if (options.use_pam && authenticated) {
415 				Buffer m;
416 
417 				buffer_init(&m);
418 				mm_request_receive_expect(pmonitor->m_sendfd,
419 				    MONITOR_REQ_PAM_ACCOUNT, &m);
420 				authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m);
421 				buffer_free(&m);
422 			}
423 #endif
424 		}
425 		if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
426 			auth_log(authctxt, authenticated, partial,
427 			    auth_method, auth_submethod);
428 			if (!authenticated)
429 				authctxt->failures++;
430 		}
431 	}
432 
433 	if (!authctxt->valid)
434 		fatal("%s: authenticated invalid user", __func__);
435 	if (strcmp(auth_method, "unknown") == 0)
436 		fatal("%s: authentication method name unknown", __func__);
437 
438 	debug("%s: %s has been authenticated by privileged process",
439 	    __func__, authctxt->user);
440 
441 	mm_get_keystate(pmonitor);
442 
443 	/* Drain any buffered messages from the child */
444 	while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
445 		;
446 
447 	close(pmonitor->m_sendfd);
448 	close(pmonitor->m_log_recvfd);
449 	pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
450 }
451 
452 static void
453 monitor_set_child_handler(pid_t pid)
454 {
455 	monitor_child_pid = pid;
456 }
457 
458 static void
459 monitor_child_handler(int sig)
460 {
461 	kill(monitor_child_pid, sig);
462 }
463 
464 void
465 monitor_child_postauth(struct monitor *pmonitor)
466 {
467 	close(pmonitor->m_recvfd);
468 	pmonitor->m_recvfd = -1;
469 
470 	monitor_set_child_handler(pmonitor->m_pid);
471 	signal(SIGHUP, &monitor_child_handler);
472 	signal(SIGTERM, &monitor_child_handler);
473 	signal(SIGINT, &monitor_child_handler);
474 #ifdef SIGXFSZ
475 	signal(SIGXFSZ, SIG_IGN);
476 #endif
477 
478 	if (compat20) {
479 		mon_dispatch = mon_dispatch_postauth20;
480 
481 		/* Permit requests for moduli and signatures */
482 		monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
483 		monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
484 		monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
485 	} else {
486 		mon_dispatch = mon_dispatch_postauth15;
487 		monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
488 	}
489 	if (!no_pty_flag) {
490 		monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
491 		monitor_permit(mon_dispatch, MONITOR_REQ_PTYCLEANUP, 1);
492 	}
493 
494 	for (;;)
495 		monitor_read(pmonitor, mon_dispatch, NULL);
496 }
497 
498 void
499 monitor_sync(struct monitor *pmonitor)
500 {
501 	if (options.compression) {
502 		/* The member allocation is not visible, so sync it */
503 		mm_share_sync(&pmonitor->m_zlib, &pmonitor->m_zback);
504 	}
505 }
506 
507 static int
508 monitor_read_log(struct monitor *pmonitor)
509 {
510 	Buffer logmsg;
511 	u_int len, level;
512 	char *msg;
513 
514 	buffer_init(&logmsg);
515 
516 	/* Read length */
517 	buffer_append_space(&logmsg, 4);
518 	if (atomicio(read, pmonitor->m_log_recvfd,
519 	    buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) {
520 		if (errno == EPIPE) {
521 			buffer_free(&logmsg);
522 			debug("%s: child log fd closed", __func__);
523 			close(pmonitor->m_log_recvfd);
524 			pmonitor->m_log_recvfd = -1;
525 			return -1;
526 		}
527 		fatal("%s: log fd read: %s", __func__, strerror(errno));
528 	}
529 	len = buffer_get_int(&logmsg);
530 	if (len <= 4 || len > 8192)
531 		fatal("%s: invalid log message length %u", __func__, len);
532 
533 	/* Read severity, message */
534 	buffer_clear(&logmsg);
535 	buffer_append_space(&logmsg, len);
536 	if (atomicio(read, pmonitor->m_log_recvfd,
537 	    buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg))
538 		fatal("%s: log fd read: %s", __func__, strerror(errno));
539 
540 	/* Log it */
541 	level = buffer_get_int(&logmsg);
542 	msg = buffer_get_string(&logmsg, NULL);
543 	if (log_level_name(level) == NULL)
544 		fatal("%s: invalid log level %u (corrupted message?)",
545 		    __func__, level);
546 	do_log2(level, "%s [preauth]", msg);
547 
548 	buffer_free(&logmsg);
549 	free(msg);
550 
551 	return 0;
552 }
553 
554 int
555 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
556     struct mon_table **pent)
557 {
558 	Buffer m;
559 	int ret;
560 	u_char type;
561 	struct pollfd pfd[2];
562 
563 	for (;;) {
564 		memset(&pfd, 0, sizeof(pfd));
565 		pfd[0].fd = pmonitor->m_sendfd;
566 		pfd[0].events = POLLIN;
567 		pfd[1].fd = pmonitor->m_log_recvfd;
568 		pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
569 		if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1) {
570 			if (errno == EINTR || errno == EAGAIN)
571 				continue;
572 			fatal("%s: poll: %s", __func__, strerror(errno));
573 		}
574 		if (pfd[1].revents) {
575 			/*
576 			 * Drain all log messages before processing next
577 			 * monitor request.
578 			 */
579 			monitor_read_log(pmonitor);
580 			continue;
581 		}
582 		if (pfd[0].revents)
583 			break;  /* Continues below */
584 	}
585 
586 	buffer_init(&m);
587 
588 	mm_request_receive(pmonitor->m_sendfd, &m);
589 	type = buffer_get_char(&m);
590 
591 	debug3("%s: checking request %d", __func__, type);
592 
593 	while (ent->f != NULL) {
594 		if (ent->type == type)
595 			break;
596 		ent++;
597 	}
598 
599 	if (ent->f != NULL) {
600 		if (!(ent->flags & MON_PERMIT))
601 			fatal("%s: unpermitted request %d", __func__,
602 			    type);
603 		ret = (*ent->f)(pmonitor->m_sendfd, &m);
604 		buffer_free(&m);
605 
606 		/* The child may use this request only once, disable it */
607 		if (ent->flags & MON_ONCE) {
608 			debug2("%s: %d used once, disabling now", __func__,
609 			    type);
610 			ent->flags &= ~MON_PERMIT;
611 		}
612 
613 		if (pent != NULL)
614 			*pent = ent;
615 
616 		return ret;
617 	}
618 
619 	fatal("%s: unsupported request: %d", __func__, type);
620 
621 	/* NOTREACHED */
622 	return (-1);
623 }
624 
625 /* allowed key state */
626 static int
627 monitor_allowed_key(u_char *blob, u_int bloblen)
628 {
629 	/* make sure key is allowed */
630 	if (key_blob == NULL || key_bloblen != bloblen ||
631 	    timingsafe_bcmp(key_blob, blob, key_bloblen))
632 		return (0);
633 	return (1);
634 }
635 
636 static void
637 monitor_reset_key_state(void)
638 {
639 	/* reset state */
640 	free(key_blob);
641 	free(hostbased_cuser);
642 	free(hostbased_chost);
643 	key_blob = NULL;
644 	key_bloblen = 0;
645 	key_blobtype = MM_NOKEY;
646 	hostbased_cuser = NULL;
647 	hostbased_chost = NULL;
648 }
649 
650 #ifdef WITH_OPENSSL
651 int
652 mm_answer_moduli(int sock, Buffer *m)
653 {
654 	DH *dh;
655 	int min, want, max;
656 
657 	min = buffer_get_int(m);
658 	want = buffer_get_int(m);
659 	max = buffer_get_int(m);
660 
661 	debug3("%s: got parameters: %d %d %d",
662 	    __func__, min, want, max);
663 	/* We need to check here, too, in case the child got corrupted */
664 	if (max < min || want < min || max < want)
665 		fatal("%s: bad parameters: %d %d %d",
666 		    __func__, min, want, max);
667 
668 	buffer_clear(m);
669 
670 	dh = choose_dh(min, want, max);
671 	if (dh == NULL) {
672 		buffer_put_char(m, 0);
673 		return (0);
674 	} else {
675 		/* Send first bignum */
676 		buffer_put_char(m, 1);
677 		buffer_put_bignum2(m, dh->p);
678 		buffer_put_bignum2(m, dh->g);
679 
680 		DH_free(dh);
681 	}
682 	mm_request_send(sock, MONITOR_ANS_MODULI, m);
683 	return (0);
684 }
685 #endif
686 
687 extern AuthenticationConnection *auth_conn;
688 
689 int
690 mm_answer_sign(int sock, Buffer *m)
691 {
692 	Key *key;
693 	u_char *p;
694 	u_char *signature;
695 	u_int siglen, datlen;
696 	int keyid;
697 
698 	debug3("%s", __func__);
699 
700 	keyid = buffer_get_int(m);
701 	p = buffer_get_string(m, &datlen);
702 
703 	/*
704 	 * Supported KEX types use SHA1 (20 bytes), SHA256 (32 bytes),
705 	 * SHA384 (48 bytes) and SHA512 (64 bytes).
706 	 */
707 	if (datlen != 20 && datlen != 32 && datlen != 48 && datlen != 64)
708 		fatal("%s: data length incorrect: %u", __func__, datlen);
709 
710 	/* save session id, it will be passed on the first call */
711 	if (session_id2_len == 0) {
712 		session_id2_len = datlen;
713 		session_id2 = xmalloc(session_id2_len);
714 		memcpy(session_id2, p, session_id2_len);
715 	}
716 
717 	if ((key = get_hostkey_by_index(keyid)) != NULL) {
718 		if (key_sign(key, &signature, &siglen, p, datlen) < 0)
719 			fatal("%s: key_sign failed", __func__);
720 	} else if ((key = get_hostkey_public_by_index(keyid)) != NULL &&
721 	    auth_conn != NULL) {
722 		if (ssh_agent_sign(auth_conn, key, &signature, &siglen, p,
723 		    datlen) < 0)
724 			fatal("%s: ssh_agent_sign failed", __func__);
725 	} else
726 		fatal("%s: no hostkey from index %d", __func__, keyid);
727 
728 	debug3("%s: signature %p(%u)", __func__, signature, siglen);
729 
730 	buffer_clear(m);
731 	buffer_put_string(m, signature, siglen);
732 
733 	free(p);
734 	free(signature);
735 
736 	mm_request_send(sock, MONITOR_ANS_SIGN, m);
737 
738 	/* Turn on permissions for getpwnam */
739 	monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
740 
741 	return (0);
742 }
743 
744 /* Retrieves the password entry and also checks if the user is permitted */
745 
746 int
747 mm_answer_pwnamallow(int sock, Buffer *m)
748 {
749 	char *username;
750 	struct passwd *pwent;
751 	int allowed = 0;
752 	u_int i;
753 
754 	debug3("%s", __func__);
755 
756 	if (authctxt->attempt++ != 0)
757 		fatal("%s: multiple attempts for getpwnam", __func__);
758 
759 	username = buffer_get_string(m, NULL);
760 
761 	pwent = getpwnamallow(username);
762 
763 	authctxt->user = xstrdup(username);
764 	setproctitle("%s [priv]", pwent ? username : "unknown");
765 	free(username);
766 
767 	buffer_clear(m);
768 
769 	if (pwent == NULL) {
770 		buffer_put_char(m, 0);
771 		authctxt->pw = fakepw();
772 		goto out;
773 	}
774 
775 	allowed = 1;
776 	authctxt->pw = pwent;
777 	authctxt->valid = 1;
778 
779 	buffer_put_char(m, 1);
780 	buffer_put_string(m, pwent, sizeof(struct passwd));
781 	buffer_put_cstring(m, pwent->pw_name);
782 	buffer_put_cstring(m, "*");
783 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
784 	buffer_put_cstring(m, pwent->pw_gecos);
785 #endif
786 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
787 	buffer_put_cstring(m, pwent->pw_class);
788 #endif
789 	buffer_put_cstring(m, pwent->pw_dir);
790 	buffer_put_cstring(m, pwent->pw_shell);
791 
792  out:
793 	buffer_put_string(m, &options, sizeof(options));
794 
795 #define M_CP_STROPT(x) do { \
796 		if (options.x != NULL) \
797 			buffer_put_cstring(m, options.x); \
798 	} while (0)
799 #define M_CP_STRARRAYOPT(x, nx) do { \
800 		for (i = 0; i < options.nx; i++) \
801 			buffer_put_cstring(m, options.x[i]); \
802 	} while (0)
803 	/* See comment in servconf.h */
804 	COPY_MATCH_STRING_OPTS();
805 #undef M_CP_STROPT
806 #undef M_CP_STRARRAYOPT
807 
808 	/* Create valid auth method lists */
809 	if (compat20 && auth2_setup_methods_lists(authctxt) != 0) {
810 		/*
811 		 * The monitor will continue long enough to let the child
812 		 * run to it's packet_disconnect(), but it must not allow any
813 		 * authentication to succeed.
814 		 */
815 		debug("%s: no valid authentication method lists", __func__);
816 	}
817 
818 	debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
819 	mm_request_send(sock, MONITOR_ANS_PWNAM, m);
820 
821 	/* For SSHv1 allow authentication now */
822 	if (!compat20)
823 		monitor_permit_authentications(1);
824 	else {
825 		/* Allow service/style information on the auth context */
826 		monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
827 		monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
828 	}
829 #ifdef USE_PAM
830 	if (options.use_pam)
831 		monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
832 #endif
833 
834 	return (0);
835 }
836 
837 int mm_answer_auth2_read_banner(int sock, Buffer *m)
838 {
839 	char *banner;
840 
841 	buffer_clear(m);
842 	banner = auth2_read_banner();
843 	buffer_put_cstring(m, banner != NULL ? banner : "");
844 	mm_request_send(sock, MONITOR_ANS_AUTH2_READ_BANNER, m);
845 	free(banner);
846 
847 	return (0);
848 }
849 
850 int
851 mm_answer_authserv(int sock, Buffer *m)
852 {
853 	monitor_permit_authentications(1);
854 
855 	authctxt->service = buffer_get_string(m, NULL);
856 	authctxt->style = buffer_get_string(m, NULL);
857 	debug3("%s: service=%s, style=%s",
858 	    __func__, authctxt->service, authctxt->style);
859 
860 	if (strlen(authctxt->style) == 0) {
861 		free(authctxt->style);
862 		authctxt->style = NULL;
863 	}
864 
865 	return (0);
866 }
867 
868 int
869 mm_answer_authpassword(int sock, Buffer *m)
870 {
871 	static int call_count;
872 	char *passwd;
873 	int authenticated;
874 	u_int plen;
875 
876 	passwd = buffer_get_string(m, &plen);
877 	/* Only authenticate if the context is valid */
878 	authenticated = options.password_authentication &&
879 	    auth_password(authctxt, passwd);
880 	explicit_bzero(passwd, strlen(passwd));
881 	free(passwd);
882 
883 	buffer_clear(m);
884 	buffer_put_int(m, authenticated);
885 
886 	debug3("%s: sending result %d", __func__, authenticated);
887 	mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m);
888 
889 	call_count++;
890 	if (plen == 0 && call_count == 1)
891 		auth_method = "none";
892 	else
893 		auth_method = "password";
894 
895 	/* Causes monitor loop to terminate if authenticated */
896 	return (authenticated);
897 }
898 
899 #ifdef BSD_AUTH
900 int
901 mm_answer_bsdauthquery(int sock, Buffer *m)
902 {
903 	char *name, *infotxt;
904 	u_int numprompts;
905 	u_int *echo_on;
906 	char **prompts;
907 	u_int success;
908 
909 	success = bsdauth_query(authctxt, &name, &infotxt, &numprompts,
910 	    &prompts, &echo_on) < 0 ? 0 : 1;
911 
912 	buffer_clear(m);
913 	buffer_put_int(m, success);
914 	if (success)
915 		buffer_put_cstring(m, prompts[0]);
916 
917 	debug3("%s: sending challenge success: %u", __func__, success);
918 	mm_request_send(sock, MONITOR_ANS_BSDAUTHQUERY, m);
919 
920 	if (success) {
921 		free(name);
922 		free(infotxt);
923 		free(prompts);
924 		free(echo_on);
925 	}
926 
927 	return (0);
928 }
929 
930 int
931 mm_answer_bsdauthrespond(int sock, Buffer *m)
932 {
933 	char *response;
934 	int authok;
935 
936 	if (authctxt->as == 0)
937 		fatal("%s: no bsd auth session", __func__);
938 
939 	response = buffer_get_string(m, NULL);
940 	authok = options.challenge_response_authentication &&
941 	    auth_userresponse(authctxt->as, response, 0);
942 	authctxt->as = NULL;
943 	debug3("%s: <%s> = <%d>", __func__, response, authok);
944 	free(response);
945 
946 	buffer_clear(m);
947 	buffer_put_int(m, authok);
948 
949 	debug3("%s: sending authenticated: %d", __func__, authok);
950 	mm_request_send(sock, MONITOR_ANS_BSDAUTHRESPOND, m);
951 
952 	if (compat20) {
953 		auth_method = "keyboard-interactive";
954 		auth_submethod = "bsdauth";
955 	} else
956 		auth_method = "bsdauth";
957 
958 	return (authok != 0);
959 }
960 #endif
961 
962 #ifdef SKEY
963 int
964 mm_answer_skeyquery(int sock, Buffer *m)
965 {
966 	struct skey skey;
967 	char challenge[1024];
968 	u_int success;
969 
970 	success = _compat_skeychallenge(&skey, authctxt->user, challenge,
971 	    sizeof(challenge)) < 0 ? 0 : 1;
972 
973 	buffer_clear(m);
974 	buffer_put_int(m, success);
975 	if (success)
976 		buffer_put_cstring(m, challenge);
977 
978 	debug3("%s: sending challenge success: %u", __func__, success);
979 	mm_request_send(sock, MONITOR_ANS_SKEYQUERY, m);
980 
981 	return (0);
982 }
983 
984 int
985 mm_answer_skeyrespond(int sock, Buffer *m)
986 {
987 	char *response;
988 	int authok;
989 
990 	response = buffer_get_string(m, NULL);
991 
992 	authok = (options.challenge_response_authentication &&
993 	    authctxt->valid &&
994 	    skey_haskey(authctxt->pw->pw_name) == 0 &&
995 	    skey_passcheck(authctxt->pw->pw_name, response) != -1);
996 
997 	free(response);
998 
999 	buffer_clear(m);
1000 	buffer_put_int(m, authok);
1001 
1002 	debug3("%s: sending authenticated: %d", __func__, authok);
1003 	mm_request_send(sock, MONITOR_ANS_SKEYRESPOND, m);
1004 
1005 	auth_method = "skey";
1006 
1007 	return (authok != 0);
1008 }
1009 #endif
1010 
1011 #ifdef USE_PAM
1012 int
1013 mm_answer_pam_start(int sock, Buffer *m)
1014 {
1015 	if (!options.use_pam)
1016 		fatal("UsePAM not set, but ended up in %s anyway", __func__);
1017 
1018 	start_pam(authctxt);
1019 
1020 	monitor_permit(mon_dispatch, MONITOR_REQ_PAM_ACCOUNT, 1);
1021 
1022 	return (0);
1023 }
1024 
1025 int
1026 mm_answer_pam_account(int sock, Buffer *m)
1027 {
1028 	u_int ret;
1029 
1030 	if (!options.use_pam)
1031 		fatal("UsePAM not set, but ended up in %s anyway", __func__);
1032 
1033 	ret = do_pam_account();
1034 
1035 	buffer_put_int(m, ret);
1036 	buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1037 
1038 	mm_request_send(sock, MONITOR_ANS_PAM_ACCOUNT, m);
1039 
1040 	return (ret);
1041 }
1042 
1043 static void *sshpam_ctxt, *sshpam_authok;
1044 extern KbdintDevice sshpam_device;
1045 
1046 int
1047 mm_answer_pam_init_ctx(int sock, Buffer *m)
1048 {
1049 	debug3("%s", __func__);
1050 	sshpam_ctxt = (sshpam_device.init_ctx)(authctxt);
1051 	sshpam_authok = NULL;
1052 	buffer_clear(m);
1053 	if (sshpam_ctxt != NULL) {
1054 		monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
1055 		buffer_put_int(m, 1);
1056 	} else {
1057 		buffer_put_int(m, 0);
1058 	}
1059 	mm_request_send(sock, MONITOR_ANS_PAM_INIT_CTX, m);
1060 	return (0);
1061 }
1062 
1063 int
1064 mm_answer_pam_query(int sock, Buffer *m)
1065 {
1066 	char *name = NULL, *info = NULL, **prompts = NULL;
1067 	u_int i, num = 0, *echo_on = 0;
1068 	int ret;
1069 
1070 	debug3("%s", __func__);
1071 	sshpam_authok = NULL;
1072 	ret = (sshpam_device.query)(sshpam_ctxt, &name, &info, &num, &prompts, &echo_on);
1073 	if (ret == 0 && num == 0)
1074 		sshpam_authok = sshpam_ctxt;
1075 	if (num > 1 || name == NULL || info == NULL)
1076 		ret = -1;
1077 	buffer_clear(m);
1078 	buffer_put_int(m, ret);
1079 	buffer_put_cstring(m, name);
1080 	free(name);
1081 	buffer_put_cstring(m, info);
1082 	free(info);
1083 	buffer_put_int(m, num);
1084 	for (i = 0; i < num; ++i) {
1085 		buffer_put_cstring(m, prompts[i]);
1086 		free(prompts[i]);
1087 		buffer_put_int(m, echo_on[i]);
1088 	}
1089 	free(prompts);
1090 	free(echo_on);
1091 	auth_method = "keyboard-interactive";
1092 	auth_submethod = "pam";
1093 	mm_request_send(sock, MONITOR_ANS_PAM_QUERY, m);
1094 	return (0);
1095 }
1096 
1097 int
1098 mm_answer_pam_respond(int sock, Buffer *m)
1099 {
1100 	char **resp;
1101 	u_int i, num;
1102 	int ret;
1103 
1104 	debug3("%s", __func__);
1105 	sshpam_authok = NULL;
1106 	num = buffer_get_int(m);
1107 	if (num > 0) {
1108 		resp = xcalloc(num, sizeof(char *));
1109 		for (i = 0; i < num; ++i)
1110 			resp[i] = buffer_get_string(m, NULL);
1111 		ret = (sshpam_device.respond)(sshpam_ctxt, num, resp);
1112 		for (i = 0; i < num; ++i)
1113 			free(resp[i]);
1114 		free(resp);
1115 	} else {
1116 		ret = (sshpam_device.respond)(sshpam_ctxt, num, NULL);
1117 	}
1118 	buffer_clear(m);
1119 	buffer_put_int(m, ret);
1120 	mm_request_send(sock, MONITOR_ANS_PAM_RESPOND, m);
1121 	auth_method = "keyboard-interactive";
1122 	auth_submethod = "pam";
1123 	if (ret == 0)
1124 		sshpam_authok = sshpam_ctxt;
1125 	return (0);
1126 }
1127 
1128 int
1129 mm_answer_pam_free_ctx(int sock, Buffer *m)
1130 {
1131 	int r = sshpam_authok != NULL && sshpam_authok == sshpam_ctxt;
1132 
1133 	debug3("%s", __func__);
1134 	(sshpam_device.free_ctx)(sshpam_ctxt);
1135 	sshpam_ctxt = sshpam_authok = NULL;
1136 	buffer_clear(m);
1137 	mm_request_send(sock, MONITOR_ANS_PAM_FREE_CTX, m);
1138 	auth_method = "keyboard-interactive";
1139 	auth_submethod = "pam";
1140 	return r;
1141 }
1142 #endif
1143 
1144 int
1145 mm_answer_keyallowed(int sock, Buffer *m)
1146 {
1147 	Key *key;
1148 	char *cuser, *chost;
1149 	u_char *blob;
1150 	u_int bloblen;
1151 	enum mm_keytype type = 0;
1152 	int allowed = 0;
1153 
1154 	debug3("%s entering", __func__);
1155 
1156 	type = buffer_get_int(m);
1157 	cuser = buffer_get_string(m, NULL);
1158 	chost = buffer_get_string(m, NULL);
1159 	blob = buffer_get_string(m, &bloblen);
1160 
1161 	key = key_from_blob(blob, bloblen);
1162 
1163 	if ((compat20 && type == MM_RSAHOSTKEY) ||
1164 	    (!compat20 && type != MM_RSAHOSTKEY))
1165 		fatal("%s: key type and protocol mismatch", __func__);
1166 
1167 	debug3("%s: key_from_blob: %p", __func__, key);
1168 
1169 	if (key != NULL && authctxt->valid) {
1170 		switch (type) {
1171 		case MM_USERKEY:
1172 			allowed = options.pubkey_authentication &&
1173 			    user_key_allowed(authctxt->pw, key);
1174 			pubkey_auth_info(authctxt, key, NULL);
1175 			auth_method = "publickey";
1176 			if (options.pubkey_authentication && allowed != 1)
1177 				auth_clear_options();
1178 			break;
1179 		case MM_HOSTKEY:
1180 			allowed = options.hostbased_authentication &&
1181 			    hostbased_key_allowed(authctxt->pw,
1182 			    cuser, chost, key);
1183 			pubkey_auth_info(authctxt, key,
1184 			    "client user \"%.100s\", client host \"%.100s\"",
1185 			    cuser, chost);
1186 			auth_method = "hostbased";
1187 			break;
1188 #ifdef WITH_SSH1
1189 		case MM_RSAHOSTKEY:
1190 			key->type = KEY_RSA1; /* XXX */
1191 			allowed = options.rhosts_rsa_authentication &&
1192 			    auth_rhosts_rsa_key_allowed(authctxt->pw,
1193 			    cuser, chost, key);
1194 			if (options.rhosts_rsa_authentication && allowed != 1)
1195 				auth_clear_options();
1196 			auth_method = "rsa";
1197 			break;
1198 #endif
1199 		default:
1200 			fatal("%s: unknown key type %d", __func__, type);
1201 			break;
1202 		}
1203 	}
1204 	if (key != NULL)
1205 		key_free(key);
1206 
1207 	/* clear temporarily storage (used by verify) */
1208 	monitor_reset_key_state();
1209 
1210 	if (allowed) {
1211 		/* Save temporarily for comparison in verify */
1212 		key_blob = blob;
1213 		key_bloblen = bloblen;
1214 		key_blobtype = type;
1215 		hostbased_cuser = cuser;
1216 		hostbased_chost = chost;
1217 	} else {
1218 		/* Log failed attempt */
1219 		auth_log(authctxt, 0, 0, auth_method, NULL);
1220 		free(blob);
1221 		free(cuser);
1222 		free(chost);
1223 	}
1224 
1225 	debug3("%s: key %p is %s",
1226 	    __func__, key, allowed ? "allowed" : "not allowed");
1227 
1228 	buffer_clear(m);
1229 	buffer_put_int(m, allowed);
1230 	buffer_put_int(m, forced_command != NULL);
1231 
1232 	mm_request_send(sock, MONITOR_ANS_KEYALLOWED, m);
1233 
1234 	if (type == MM_RSAHOSTKEY)
1235 		monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1236 
1237 	return (0);
1238 }
1239 
1240 static int
1241 monitor_valid_userblob(u_char *data, u_int datalen)
1242 {
1243 	Buffer b;
1244 	char *p, *userstyle;
1245 	u_int len;
1246 	int fail = 0;
1247 
1248 	buffer_init(&b);
1249 	buffer_append(&b, data, datalen);
1250 
1251 	if (datafellows & SSH_OLD_SESSIONID) {
1252 		p = buffer_ptr(&b);
1253 		len = buffer_len(&b);
1254 		if ((session_id2 == NULL) ||
1255 		    (len < session_id2_len) ||
1256 		    (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1257 			fail++;
1258 		buffer_consume(&b, session_id2_len);
1259 	} else {
1260 		p = buffer_get_string(&b, &len);
1261 		if ((session_id2 == NULL) ||
1262 		    (len != session_id2_len) ||
1263 		    (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1264 			fail++;
1265 		free(p);
1266 	}
1267 	if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1268 		fail++;
1269 	p = buffer_get_cstring(&b, NULL);
1270 	xasprintf(&userstyle, "%s%s%s", authctxt->user,
1271 	    authctxt->style ? ":" : "",
1272 	    authctxt->style ? authctxt->style : "");
1273 	if (strcmp(userstyle, p) != 0) {
1274 		logit("wrong user name passed to monitor: expected %s != %.100s",
1275 		    userstyle, p);
1276 		fail++;
1277 	}
1278 	free(userstyle);
1279 	free(p);
1280 	buffer_skip_string(&b);
1281 	if (datafellows & SSH_BUG_PKAUTH) {
1282 		if (!buffer_get_char(&b))
1283 			fail++;
1284 	} else {
1285 		p = buffer_get_cstring(&b, NULL);
1286 		if (strcmp("publickey", p) != 0)
1287 			fail++;
1288 		free(p);
1289 		if (!buffer_get_char(&b))
1290 			fail++;
1291 		buffer_skip_string(&b);
1292 	}
1293 	buffer_skip_string(&b);
1294 	if (buffer_len(&b) != 0)
1295 		fail++;
1296 	buffer_free(&b);
1297 	return (fail == 0);
1298 }
1299 
1300 static int
1301 monitor_valid_hostbasedblob(u_char *data, u_int datalen, char *cuser,
1302     char *chost)
1303 {
1304 	Buffer b;
1305 	char *p, *userstyle;
1306 	u_int len;
1307 	int fail = 0;
1308 
1309 	buffer_init(&b);
1310 	buffer_append(&b, data, datalen);
1311 
1312 	p = buffer_get_string(&b, &len);
1313 	if ((session_id2 == NULL) ||
1314 	    (len != session_id2_len) ||
1315 	    (timingsafe_bcmp(p, session_id2, session_id2_len) != 0))
1316 		fail++;
1317 	free(p);
1318 
1319 	if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
1320 		fail++;
1321 	p = buffer_get_cstring(&b, NULL);
1322 	xasprintf(&userstyle, "%s%s%s", authctxt->user,
1323 	    authctxt->style ? ":" : "",
1324 	    authctxt->style ? authctxt->style : "");
1325 	if (strcmp(userstyle, p) != 0) {
1326 		logit("wrong user name passed to monitor: expected %s != %.100s",
1327 		    userstyle, p);
1328 		fail++;
1329 	}
1330 	free(userstyle);
1331 	free(p);
1332 	buffer_skip_string(&b);	/* service */
1333 	p = buffer_get_cstring(&b, NULL);
1334 	if (strcmp(p, "hostbased") != 0)
1335 		fail++;
1336 	free(p);
1337 	buffer_skip_string(&b);	/* pkalg */
1338 	buffer_skip_string(&b);	/* pkblob */
1339 
1340 	/* verify client host, strip trailing dot if necessary */
1341 	p = buffer_get_string(&b, NULL);
1342 	if (((len = strlen(p)) > 0) && p[len - 1] == '.')
1343 		p[len - 1] = '\0';
1344 	if (strcmp(p, chost) != 0)
1345 		fail++;
1346 	free(p);
1347 
1348 	/* verify client user */
1349 	p = buffer_get_string(&b, NULL);
1350 	if (strcmp(p, cuser) != 0)
1351 		fail++;
1352 	free(p);
1353 
1354 	if (buffer_len(&b) != 0)
1355 		fail++;
1356 	buffer_free(&b);
1357 	return (fail == 0);
1358 }
1359 
1360 int
1361 mm_answer_keyverify(int sock, Buffer *m)
1362 {
1363 	Key *key;
1364 	u_char *signature, *data, *blob;
1365 	u_int signaturelen, datalen, bloblen;
1366 	int verified = 0;
1367 	int valid_data = 0;
1368 
1369 	blob = buffer_get_string(m, &bloblen);
1370 	signature = buffer_get_string(m, &signaturelen);
1371 	data = buffer_get_string(m, &datalen);
1372 
1373 	if (hostbased_cuser == NULL || hostbased_chost == NULL ||
1374 	  !monitor_allowed_key(blob, bloblen))
1375 		fatal("%s: bad key, not previously allowed", __func__);
1376 
1377 	key = key_from_blob(blob, bloblen);
1378 	if (key == NULL)
1379 		fatal("%s: bad public key blob", __func__);
1380 
1381 	switch (key_blobtype) {
1382 	case MM_USERKEY:
1383 		valid_data = monitor_valid_userblob(data, datalen);
1384 		break;
1385 	case MM_HOSTKEY:
1386 		valid_data = monitor_valid_hostbasedblob(data, datalen,
1387 		    hostbased_cuser, hostbased_chost);
1388 		break;
1389 	default:
1390 		valid_data = 0;
1391 		break;
1392 	}
1393 	if (!valid_data)
1394 		fatal("%s: bad signature data blob", __func__);
1395 
1396 	verified = key_verify(key, signature, signaturelen, data, datalen);
1397 	debug3("%s: key %p signature %s",
1398 	    __func__, key, (verified == 1) ? "verified" : "unverified");
1399 
1400 	key_free(key);
1401 	free(blob);
1402 	free(signature);
1403 	free(data);
1404 
1405 	auth_method = key_blobtype == MM_USERKEY ? "publickey" : "hostbased";
1406 
1407 	monitor_reset_key_state();
1408 
1409 	buffer_clear(m);
1410 	buffer_put_int(m, verified);
1411 	mm_request_send(sock, MONITOR_ANS_KEYVERIFY, m);
1412 
1413 	return (verified == 1);
1414 }
1415 
1416 static void
1417 mm_record_login(Session *s, struct passwd *pw)
1418 {
1419 	socklen_t fromlen;
1420 	struct sockaddr_storage from;
1421 
1422 	/*
1423 	 * Get IP address of client. If the connection is not a socket, let
1424 	 * the address be 0.0.0.0.
1425 	 */
1426 	memset(&from, 0, sizeof(from));
1427 	fromlen = sizeof(from);
1428 	if (packet_connection_is_on_socket()) {
1429 		if (getpeername(packet_get_connection_in(),
1430 		    (struct sockaddr *)&from, &fromlen) < 0) {
1431 			debug("getpeername: %.100s", strerror(errno));
1432 			cleanup_exit(255);
1433 		}
1434 	}
1435 	/* Record that there was a login on that tty from the remote host. */
1436 	record_login(s->pid, s->tty, pw->pw_name, pw->pw_uid,
1437 	    get_remote_name_or_ip(utmp_len, options.use_dns),
1438 	    (struct sockaddr *)&from, fromlen);
1439 }
1440 
1441 static void
1442 mm_session_close(Session *s)
1443 {
1444 	debug3("%s: session %d pid %ld", __func__, s->self, (long)s->pid);
1445 	if (s->ttyfd != -1) {
1446 		debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ptyfd);
1447 		session_pty_cleanup2(s);
1448 	}
1449 	session_unused(s->self);
1450 }
1451 
1452 int
1453 mm_answer_pty(int sock, Buffer *m)
1454 {
1455 	extern struct monitor *pmonitor;
1456 	Session *s;
1457 	int res, fd0;
1458 
1459 	debug3("%s entering", __func__);
1460 
1461 	buffer_clear(m);
1462 	s = session_new();
1463 	if (s == NULL)
1464 		goto error;
1465 	s->authctxt = authctxt;
1466 	s->pw = authctxt->pw;
1467 	s->pid = pmonitor->m_pid;
1468 	res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty));
1469 	if (res == 0)
1470 		goto error;
1471 	pty_setowner(authctxt->pw, s->tty);
1472 
1473 	buffer_put_int(m, 1);
1474 	buffer_put_cstring(m, s->tty);
1475 
1476 	/* We need to trick ttyslot */
1477 	if (dup2(s->ttyfd, 0) == -1)
1478 		fatal("%s: dup2", __func__);
1479 
1480 	mm_record_login(s, authctxt->pw);
1481 
1482 	/* Now we can close the file descriptor again */
1483 	close(0);
1484 
1485 	/* send messages generated by record_login */
1486 	buffer_put_string(m, buffer_ptr(&loginmsg), buffer_len(&loginmsg));
1487 	buffer_clear(&loginmsg);
1488 
1489 	mm_request_send(sock, MONITOR_ANS_PTY, m);
1490 
1491 	if (mm_send_fd(sock, s->ptyfd) == -1 ||
1492 	    mm_send_fd(sock, s->ttyfd) == -1)
1493 		fatal("%s: send fds failed", __func__);
1494 
1495 	/* make sure nothing uses fd 0 */
1496 	if ((fd0 = open(_PATH_DEVNULL, O_RDONLY)) < 0)
1497 		fatal("%s: open(/dev/null): %s", __func__, strerror(errno));
1498 	if (fd0 != 0)
1499 		error("%s: fd0 %d != 0", __func__, fd0);
1500 
1501 	/* slave is not needed */
1502 	close(s->ttyfd);
1503 	s->ttyfd = s->ptyfd;
1504 	/* no need to dup() because nobody closes ptyfd */
1505 	s->ptymaster = s->ptyfd;
1506 
1507 	debug3("%s: tty %s ptyfd %d", __func__, s->tty, s->ttyfd);
1508 
1509 	return (0);
1510 
1511  error:
1512 	if (s != NULL)
1513 		mm_session_close(s);
1514 	buffer_put_int(m, 0);
1515 	mm_request_send(sock, MONITOR_ANS_PTY, m);
1516 	return (0);
1517 }
1518 
1519 int
1520 mm_answer_pty_cleanup(int sock, Buffer *m)
1521 {
1522 	Session *s;
1523 	char *tty;
1524 
1525 	debug3("%s entering", __func__);
1526 
1527 	tty = buffer_get_string(m, NULL);
1528 	if ((s = session_by_tty(tty)) != NULL)
1529 		mm_session_close(s);
1530 	buffer_clear(m);
1531 	free(tty);
1532 	return (0);
1533 }
1534 
1535 #ifdef WITH_SSH1
1536 int
1537 mm_answer_sesskey(int sock, Buffer *m)
1538 {
1539 	BIGNUM *p;
1540 	int rsafail;
1541 
1542 	/* Turn off permissions */
1543 	monitor_permit(mon_dispatch, MONITOR_REQ_SESSKEY, 0);
1544 
1545 	if ((p = BN_new()) == NULL)
1546 		fatal("%s: BN_new", __func__);
1547 
1548 	buffer_get_bignum2(m, p);
1549 
1550 	rsafail = ssh1_session_key(p);
1551 
1552 	buffer_clear(m);
1553 	buffer_put_int(m, rsafail);
1554 	buffer_put_bignum2(m, p);
1555 
1556 	BN_clear_free(p);
1557 
1558 	mm_request_send(sock, MONITOR_ANS_SESSKEY, m);
1559 
1560 	/* Turn on permissions for sessid passing */
1561 	monitor_permit(mon_dispatch, MONITOR_REQ_SESSID, 1);
1562 
1563 	return (0);
1564 }
1565 
1566 int
1567 mm_answer_sessid(int sock, Buffer *m)
1568 {
1569 	int i;
1570 
1571 	debug3("%s entering", __func__);
1572 
1573 	if (buffer_len(m) != 16)
1574 		fatal("%s: bad ssh1 session id", __func__);
1575 	for (i = 0; i < 16; i++)
1576 		session_id[i] = buffer_get_char(m);
1577 
1578 	/* Turn on permissions for getpwnam */
1579 	monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
1580 
1581 	return (0);
1582 }
1583 
1584 int
1585 mm_answer_rsa_keyallowed(int sock, Buffer *m)
1586 {
1587 	BIGNUM *client_n;
1588 	Key *key = NULL;
1589 	u_char *blob = NULL;
1590 	u_int blen = 0;
1591 	int allowed = 0;
1592 
1593 	debug3("%s entering", __func__);
1594 
1595 	auth_method = "rsa";
1596 	if (options.rsa_authentication && authctxt->valid) {
1597 		if ((client_n = BN_new()) == NULL)
1598 			fatal("%s: BN_new", __func__);
1599 		buffer_get_bignum2(m, client_n);
1600 		allowed = auth_rsa_key_allowed(authctxt->pw, client_n, &key);
1601 		BN_clear_free(client_n);
1602 	}
1603 	buffer_clear(m);
1604 	buffer_put_int(m, allowed);
1605 	buffer_put_int(m, forced_command != NULL);
1606 
1607 	/* clear temporarily storage (used by generate challenge) */
1608 	monitor_reset_key_state();
1609 
1610 	if (allowed && key != NULL) {
1611 		key->type = KEY_RSA;	/* cheat for key_to_blob */
1612 		if (key_to_blob(key, &blob, &blen) == 0)
1613 			fatal("%s: key_to_blob failed", __func__);
1614 		buffer_put_string(m, blob, blen);
1615 
1616 		/* Save temporarily for comparison in verify */
1617 		key_blob = blob;
1618 		key_bloblen = blen;
1619 		key_blobtype = MM_RSAUSERKEY;
1620 	}
1621 	if (key != NULL)
1622 		key_free(key);
1623 
1624 	mm_request_send(sock, MONITOR_ANS_RSAKEYALLOWED, m);
1625 
1626 	monitor_permit(mon_dispatch, MONITOR_REQ_RSACHALLENGE, allowed);
1627 	monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 0);
1628 	return (0);
1629 }
1630 
1631 int
1632 mm_answer_rsa_challenge(int sock, Buffer *m)
1633 {
1634 	Key *key = NULL;
1635 	u_char *blob;
1636 	u_int blen;
1637 
1638 	debug3("%s entering", __func__);
1639 
1640 	if (!authctxt->valid)
1641 		fatal("%s: authctxt not valid", __func__);
1642 	blob = buffer_get_string(m, &blen);
1643 	if (!monitor_allowed_key(blob, blen))
1644 		fatal("%s: bad key, not previously allowed", __func__);
1645 	if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1646 		fatal("%s: key type mismatch", __func__);
1647 	if ((key = key_from_blob(blob, blen)) == NULL)
1648 		fatal("%s: received bad key", __func__);
1649 	if (key->type != KEY_RSA)
1650 		fatal("%s: received bad key type %d", __func__, key->type);
1651 	key->type = KEY_RSA1;
1652 	if (ssh1_challenge)
1653 		BN_clear_free(ssh1_challenge);
1654 	ssh1_challenge = auth_rsa_generate_challenge(key);
1655 
1656 	buffer_clear(m);
1657 	buffer_put_bignum2(m, ssh1_challenge);
1658 
1659 	debug3("%s sending reply", __func__);
1660 	mm_request_send(sock, MONITOR_ANS_RSACHALLENGE, m);
1661 
1662 	monitor_permit(mon_dispatch, MONITOR_REQ_RSARESPONSE, 1);
1663 
1664 	free(blob);
1665 	key_free(key);
1666 	return (0);
1667 }
1668 
1669 int
1670 mm_answer_rsa_response(int sock, Buffer *m)
1671 {
1672 	Key *key = NULL;
1673 	u_char *blob, *response;
1674 	u_int blen, len;
1675 	int success;
1676 
1677 	debug3("%s entering", __func__);
1678 
1679 	if (!authctxt->valid)
1680 		fatal("%s: authctxt not valid", __func__);
1681 	if (ssh1_challenge == NULL)
1682 		fatal("%s: no ssh1_challenge", __func__);
1683 
1684 	blob = buffer_get_string(m, &blen);
1685 	if (!monitor_allowed_key(blob, blen))
1686 		fatal("%s: bad key, not previously allowed", __func__);
1687 	if (key_blobtype != MM_RSAUSERKEY && key_blobtype != MM_RSAHOSTKEY)
1688 		fatal("%s: key type mismatch: %d", __func__, key_blobtype);
1689 	if ((key = key_from_blob(blob, blen)) == NULL)
1690 		fatal("%s: received bad key", __func__);
1691 	response = buffer_get_string(m, &len);
1692 	if (len != 16)
1693 		fatal("%s: received bad response to challenge", __func__);
1694 	success = auth_rsa_verify_response(key, ssh1_challenge, response);
1695 
1696 	free(blob);
1697 	key_free(key);
1698 	free(response);
1699 
1700 	auth_method = key_blobtype == MM_RSAUSERKEY ? "rsa" : "rhosts-rsa";
1701 
1702 	/* reset state */
1703 	BN_clear_free(ssh1_challenge);
1704 	ssh1_challenge = NULL;
1705 	monitor_reset_key_state();
1706 
1707 	buffer_clear(m);
1708 	buffer_put_int(m, success);
1709 	mm_request_send(sock, MONITOR_ANS_RSARESPONSE, m);
1710 
1711 	return (success);
1712 }
1713 #endif
1714 
1715 int
1716 mm_answer_term(int sock, Buffer *req)
1717 {
1718 	extern struct monitor *pmonitor;
1719 	int res, status;
1720 
1721 	debug3("%s: tearing down sessions", __func__);
1722 
1723 	/* The child is terminating */
1724 	session_destroy_all(&mm_session_close);
1725 
1726 #ifdef USE_PAM
1727 	if (options.use_pam)
1728 		sshpam_cleanup();
1729 #endif
1730 
1731 	while (waitpid(pmonitor->m_pid, &status, 0) == -1)
1732 		if (errno != EINTR)
1733 			exit(1);
1734 
1735 	res = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
1736 
1737 	/* Terminate process */
1738 	exit(res);
1739 }
1740 
1741 #ifdef SSH_AUDIT_EVENTS
1742 /* Report that an audit event occurred */
1743 int
1744 mm_answer_audit_event(int socket, Buffer *m)
1745 {
1746 	ssh_audit_event_t event;
1747 
1748 	debug3("%s entering", __func__);
1749 
1750 	event = buffer_get_int(m);
1751 	switch(event) {
1752 	case SSH_AUTH_FAIL_PUBKEY:
1753 	case SSH_AUTH_FAIL_HOSTBASED:
1754 	case SSH_AUTH_FAIL_GSSAPI:
1755 	case SSH_LOGIN_EXCEED_MAXTRIES:
1756 	case SSH_LOGIN_ROOT_DENIED:
1757 	case SSH_CONNECTION_CLOSE:
1758 	case SSH_INVALID_USER:
1759 		audit_event(event);
1760 		break;
1761 	default:
1762 		fatal("Audit event type %d not permitted", event);
1763 	}
1764 
1765 	return (0);
1766 }
1767 
1768 int
1769 mm_answer_audit_command(int socket, Buffer *m)
1770 {
1771 	u_int len;
1772 	char *cmd;
1773 
1774 	debug3("%s entering", __func__);
1775 	cmd = buffer_get_string(m, &len);
1776 	/* sanity check command, if so how? */
1777 	audit_run_command(cmd);
1778 	free(cmd);
1779 	return (0);
1780 }
1781 #endif /* SSH_AUDIT_EVENTS */
1782 
1783 void
1784 monitor_apply_keystate(struct monitor *pmonitor)
1785 {
1786 	if (compat20) {
1787 		set_newkeys(MODE_IN);
1788 		set_newkeys(MODE_OUT);
1789 	} else {
1790 		packet_set_protocol_flags(child_state.ssh1protoflags);
1791 		packet_set_encryption_key(child_state.ssh1key,
1792 		    child_state.ssh1keylen, child_state.ssh1cipher);
1793 		free(child_state.ssh1key);
1794 	}
1795 
1796 	/* for rc4 and other stateful ciphers */
1797 	packet_set_keycontext(MODE_OUT, child_state.keyout);
1798 	free(child_state.keyout);
1799 	packet_set_keycontext(MODE_IN, child_state.keyin);
1800 	free(child_state.keyin);
1801 
1802 	if (!compat20) {
1803 		packet_set_iv(MODE_OUT, child_state.ivout);
1804 		free(child_state.ivout);
1805 		packet_set_iv(MODE_IN, child_state.ivin);
1806 		free(child_state.ivin);
1807 	}
1808 
1809 	memcpy(&incoming_stream, &child_state.incoming,
1810 	    sizeof(incoming_stream));
1811 	memcpy(&outgoing_stream, &child_state.outgoing,
1812 	    sizeof(outgoing_stream));
1813 
1814 	/* Update with new address */
1815 	if (options.compression)
1816 		mm_init_compression(pmonitor->m_zlib);
1817 
1818 	packet_set_postauth();
1819 
1820 	if (options.rekey_limit || options.rekey_interval)
1821 		packet_set_rekey_limits((u_int32_t)options.rekey_limit,
1822 		    (time_t)options.rekey_interval);
1823 
1824 	/* Network I/O buffers */
1825 	/* XXX inefficient for large buffers, need: buffer_init_from_string */
1826 	buffer_clear(packet_get_input());
1827 	buffer_append(packet_get_input(), child_state.input, child_state.ilen);
1828 	explicit_bzero(child_state.input, child_state.ilen);
1829 	free(child_state.input);
1830 
1831 	buffer_clear(packet_get_output());
1832 	buffer_append(packet_get_output(), child_state.output,
1833 		      child_state.olen);
1834 	explicit_bzero(child_state.output, child_state.olen);
1835 	free(child_state.output);
1836 
1837 	/* Roaming */
1838 	if (compat20)
1839 		roam_set_bytes(child_state.sent_bytes, child_state.recv_bytes);
1840 }
1841 
1842 static Kex *
1843 mm_get_kex(Buffer *m)
1844 {
1845 	Kex *kex;
1846 	void *blob;
1847 	u_int bloblen;
1848 
1849 	kex = xcalloc(1, sizeof(*kex));
1850 	kex->session_id = buffer_get_string(m, &kex->session_id_len);
1851 	if (session_id2 == NULL ||
1852 	    kex->session_id_len != session_id2_len ||
1853 	    timingsafe_bcmp(kex->session_id, session_id2, session_id2_len) != 0)
1854 		fatal("mm_get_get: internal error: bad session id");
1855 	kex->we_need = buffer_get_int(m);
1856 #ifdef WITH_OPENSSL
1857 	kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1858 	kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
1859 	kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1860 	kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
1861 	kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
1862 #endif
1863 	kex->kex[KEX_C25519_SHA256] = kexc25519_server;
1864 	kex->server = 1;
1865 	kex->hostkey_type = buffer_get_int(m);
1866 	kex->kex_type = buffer_get_int(m);
1867 	blob = buffer_get_string(m, &bloblen);
1868 	buffer_init(&kex->my);
1869 	buffer_append(&kex->my, blob, bloblen);
1870 	free(blob);
1871 	blob = buffer_get_string(m, &bloblen);
1872 	buffer_init(&kex->peer);
1873 	buffer_append(&kex->peer, blob, bloblen);
1874 	free(blob);
1875 	kex->done = 1;
1876 	kex->flags = buffer_get_int(m);
1877 	kex->client_version_string = buffer_get_string(m, NULL);
1878 	kex->server_version_string = buffer_get_string(m, NULL);
1879 	kex->load_host_public_key=&get_hostkey_public_by_type;
1880 	kex->load_host_private_key=&get_hostkey_private_by_type;
1881 	kex->host_key_index=&get_hostkey_index;
1882 	kex->sign = sshd_hostkey_sign;
1883 
1884 	return (kex);
1885 }
1886 
1887 /* This function requries careful sanity checking */
1888 
1889 void
1890 mm_get_keystate(struct monitor *pmonitor)
1891 {
1892 	Buffer m;
1893 	u_char *blob, *p;
1894 	u_int bloblen, plen;
1895 	u_int32_t seqnr, packets;
1896 	u_int64_t blocks, bytes;
1897 
1898 	debug3("%s: Waiting for new keys", __func__);
1899 
1900 	buffer_init(&m);
1901 	mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_KEYEXPORT, &m);
1902 	if (!compat20) {
1903 		child_state.ssh1protoflags = buffer_get_int(&m);
1904 		child_state.ssh1cipher = buffer_get_int(&m);
1905 		child_state.ssh1key = buffer_get_string(&m,
1906 		    &child_state.ssh1keylen);
1907 		child_state.ivout = buffer_get_string(&m,
1908 		    &child_state.ivoutlen);
1909 		child_state.ivin = buffer_get_string(&m, &child_state.ivinlen);
1910 		goto skip;
1911 	} else {
1912 		/* Get the Kex for rekeying */
1913 		*pmonitor->m_pkex = mm_get_kex(&m);
1914 	}
1915 
1916 	blob = buffer_get_string(&m, &bloblen);
1917 	current_keys[MODE_OUT] = mm_newkeys_from_blob(blob, bloblen);
1918 	free(blob);
1919 
1920 	debug3("%s: Waiting for second key", __func__);
1921 	blob = buffer_get_string(&m, &bloblen);
1922 	current_keys[MODE_IN] = mm_newkeys_from_blob(blob, bloblen);
1923 	free(blob);
1924 
1925 	/* Now get sequence numbers for the packets */
1926 	seqnr = buffer_get_int(&m);
1927 	blocks = buffer_get_int64(&m);
1928 	packets = buffer_get_int(&m);
1929 	bytes = buffer_get_int64(&m);
1930 	packet_set_state(MODE_OUT, seqnr, blocks, packets, bytes);
1931 	seqnr = buffer_get_int(&m);
1932 	blocks = buffer_get_int64(&m);
1933 	packets = buffer_get_int(&m);
1934 	bytes = buffer_get_int64(&m);
1935 	packet_set_state(MODE_IN, seqnr, blocks, packets, bytes);
1936 
1937  skip:
1938 	/* Get the key context */
1939 	child_state.keyout = buffer_get_string(&m, &child_state.keyoutlen);
1940 	child_state.keyin  = buffer_get_string(&m, &child_state.keyinlen);
1941 
1942 	debug3("%s: Getting compression state", __func__);
1943 	/* Get compression state */
1944 	p = buffer_get_string(&m, &plen);
1945 	if (plen != sizeof(child_state.outgoing))
1946 		fatal("%s: bad request size", __func__);
1947 	memcpy(&child_state.outgoing, p, sizeof(child_state.outgoing));
1948 	free(p);
1949 
1950 	p = buffer_get_string(&m, &plen);
1951 	if (plen != sizeof(child_state.incoming))
1952 		fatal("%s: bad request size", __func__);
1953 	memcpy(&child_state.incoming, p, sizeof(child_state.incoming));
1954 	free(p);
1955 
1956 	/* Network I/O buffers */
1957 	debug3("%s: Getting Network I/O buffers", __func__);
1958 	child_state.input = buffer_get_string(&m, &child_state.ilen);
1959 	child_state.output = buffer_get_string(&m, &child_state.olen);
1960 
1961 	/* Roaming */
1962 	if (compat20) {
1963 		child_state.sent_bytes = buffer_get_int64(&m);
1964 		child_state.recv_bytes = buffer_get_int64(&m);
1965 	}
1966 
1967 	buffer_free(&m);
1968 }
1969 
1970 
1971 /* Allocation functions for zlib */
1972 void *
1973 mm_zalloc(struct mm_master *mm, u_int ncount, u_int size)
1974 {
1975 	size_t len = (size_t) size * ncount;
1976 	void *address;
1977 
1978 	if (len == 0 || ncount > SIZE_T_MAX / size)
1979 		fatal("%s: mm_zalloc(%u, %u)", __func__, ncount, size);
1980 
1981 	address = mm_malloc(mm, len);
1982 
1983 	return (address);
1984 }
1985 
1986 void
1987 mm_zfree(struct mm_master *mm, void *address)
1988 {
1989 	mm_free(mm, address);
1990 }
1991 
1992 void
1993 mm_init_compression(struct mm_master *mm)
1994 {
1995 	outgoing_stream.zalloc = (alloc_func)mm_zalloc;
1996 	outgoing_stream.zfree = (free_func)mm_zfree;
1997 	outgoing_stream.opaque = mm;
1998 
1999 	incoming_stream.zalloc = (alloc_func)mm_zalloc;
2000 	incoming_stream.zfree = (free_func)mm_zfree;
2001 	incoming_stream.opaque = mm;
2002 }
2003 
2004 /* XXX */
2005 
2006 #define FD_CLOSEONEXEC(x) do { \
2007 	if (fcntl(x, F_SETFD, FD_CLOEXEC) == -1) \
2008 		fatal("fcntl(%d, F_SETFD)", x); \
2009 } while (0)
2010 
2011 static void
2012 monitor_openfds(struct monitor *mon, int do_logfds)
2013 {
2014 	int pair[2];
2015 
2016 	if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
2017 		fatal("%s: socketpair: %s", __func__, strerror(errno));
2018 	FD_CLOSEONEXEC(pair[0]);
2019 	FD_CLOSEONEXEC(pair[1]);
2020 	mon->m_recvfd = pair[0];
2021 	mon->m_sendfd = pair[1];
2022 
2023 	if (do_logfds) {
2024 		if (pipe(pair) == -1)
2025 			fatal("%s: pipe: %s", __func__, strerror(errno));
2026 		FD_CLOSEONEXEC(pair[0]);
2027 		FD_CLOSEONEXEC(pair[1]);
2028 		mon->m_log_recvfd = pair[0];
2029 		mon->m_log_sendfd = pair[1];
2030 	} else
2031 		mon->m_log_recvfd = mon->m_log_sendfd = -1;
2032 }
2033 
2034 #define MM_MEMSIZE	65536
2035 
2036 struct monitor *
2037 monitor_init(void)
2038 {
2039 	struct monitor *mon;
2040 
2041 	mon = xcalloc(1, sizeof(*mon));
2042 
2043 	monitor_openfds(mon, 1);
2044 
2045 	/* Used to share zlib space across processes */
2046 	if (options.compression) {
2047 		mon->m_zback = mm_create(NULL, MM_MEMSIZE);
2048 		mon->m_zlib = mm_create(mon->m_zback, 20 * MM_MEMSIZE);
2049 
2050 		/* Compression needs to share state across borders */
2051 		mm_init_compression(mon->m_zlib);
2052 	}
2053 
2054 	return mon;
2055 }
2056 
2057 void
2058 monitor_reinit(struct monitor *mon)
2059 {
2060 	monitor_openfds(mon, 0);
2061 }
2062 
2063 #ifdef GSSAPI
2064 int
2065 mm_answer_gss_setup_ctx(int sock, Buffer *m)
2066 {
2067 	gss_OID_desc goid;
2068 	OM_uint32 major;
2069 	u_int len;
2070 
2071 	goid.elements = buffer_get_string(m, &len);
2072 	goid.length = len;
2073 
2074 	major = ssh_gssapi_server_ctx(&gsscontext, &goid);
2075 
2076 	free(goid.elements);
2077 
2078 	buffer_clear(m);
2079 	buffer_put_int(m, major);
2080 
2081 	mm_request_send(sock, MONITOR_ANS_GSSSETUP, m);
2082 
2083 	/* Now we have a context, enable the step */
2084 	monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 1);
2085 
2086 	return (0);
2087 }
2088 
2089 int
2090 mm_answer_gss_accept_ctx(int sock, Buffer *m)
2091 {
2092 	gss_buffer_desc in;
2093 	gss_buffer_desc out = GSS_C_EMPTY_BUFFER;
2094 	OM_uint32 major, minor;
2095 	OM_uint32 flags = 0; /* GSI needs this */
2096 	u_int len;
2097 
2098 	in.value = buffer_get_string(m, &len);
2099 	in.length = len;
2100 	major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags);
2101 	free(in.value);
2102 
2103 	buffer_clear(m);
2104 	buffer_put_int(m, major);
2105 	buffer_put_string(m, out.value, out.length);
2106 	buffer_put_int(m, flags);
2107 	mm_request_send(sock, MONITOR_ANS_GSSSTEP, m);
2108 
2109 	gss_release_buffer(&minor, &out);
2110 
2111 	if (major == GSS_S_COMPLETE) {
2112 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
2113 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2114 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
2115 	}
2116 	return (0);
2117 }
2118 
2119 int
2120 mm_answer_gss_checkmic(int sock, Buffer *m)
2121 {
2122 	gss_buffer_desc gssbuf, mic;
2123 	OM_uint32 ret;
2124 	u_int len;
2125 
2126 	gssbuf.value = buffer_get_string(m, &len);
2127 	gssbuf.length = len;
2128 	mic.value = buffer_get_string(m, &len);
2129 	mic.length = len;
2130 
2131 	ret = ssh_gssapi_checkmic(gsscontext, &gssbuf, &mic);
2132 
2133 	free(gssbuf.value);
2134 	free(mic.value);
2135 
2136 	buffer_clear(m);
2137 	buffer_put_int(m, ret);
2138 
2139 	mm_request_send(sock, MONITOR_ANS_GSSCHECKMIC, m);
2140 
2141 	if (!GSS_ERROR(ret))
2142 		monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2143 
2144 	return (0);
2145 }
2146 
2147 int
2148 mm_answer_gss_userok(int sock, Buffer *m)
2149 {
2150 	int authenticated;
2151 
2152 	authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
2153 
2154 	buffer_clear(m);
2155 	buffer_put_int(m, authenticated);
2156 
2157 	debug3("%s: sending result %d", __func__, authenticated);
2158 	mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
2159 
2160 	auth_method = "gssapi-with-mic";
2161 
2162 	/* Monitor loop will terminate if authenticated */
2163 	return (authenticated);
2164 }
2165 #endif /* GSSAPI */
2166 
2167