xref: /openbsd-src/usr.bin/ssh/monitor_wrap.c (revision d2c5a4743fb945f45b034a3a830a96f7e1bc695d)
1 /* $OpenBSD: monitor_wrap.c,v 1.121 2020/10/18 11:32:01 djm 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 <sys/types.h>
29 #include <sys/uio.h>
30 #include <sys/queue.h>
31 
32 #include <errno.h>
33 #include <pwd.h>
34 #include <signal.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <stdarg.h>
38 #include <unistd.h>
39 
40 #ifdef WITH_OPENSSL
41 #include <openssl/bn.h>
42 #include <openssl/dh.h>
43 #endif
44 
45 #include "xmalloc.h"
46 #include "ssh.h"
47 #ifdef WITH_OPENSSL
48 #include "dh.h"
49 #endif
50 #include "sshbuf.h"
51 #include "sshkey.h"
52 #include "cipher.h"
53 #include "kex.h"
54 #include "hostfile.h"
55 #include "auth.h"
56 #include "auth-options.h"
57 #include "packet.h"
58 #include "mac.h"
59 #include "log.h"
60 #include "monitor.h"
61 #ifdef GSSAPI
62 #include "ssh-gss.h"
63 #endif
64 #include "monitor_wrap.h"
65 #include "atomicio.h"
66 #include "monitor_fdpass.h"
67 #include "misc.h"
68 
69 #include "channels.h"
70 #include "session.h"
71 #include "servconf.h"
72 
73 #include "ssherr.h"
74 
75 /* Imports */
76 extern struct monitor *pmonitor;
77 extern struct sshbuf *loginmsg;
78 extern ServerOptions options;
79 
80 void
81 mm_log_handler(const char *file, const char *func, int line,
82     LogLevel level, const char *msg, void *ctx)
83 {
84 	struct sshbuf *log_msg;
85 	struct monitor *mon = (struct monitor *)ctx;
86 	int r;
87 	size_t len;
88 
89 	if (mon->m_log_sendfd == -1)
90 		fatal_f("no log channel");
91 
92 	if ((log_msg = sshbuf_new()) == NULL)
93 		fatal_f("sshbuf_new failed");
94 
95 	if ((r = sshbuf_put_u32(log_msg, 0)) != 0 || /* length; filled below */
96 	    (r = sshbuf_put_cstring(log_msg, file)) != 0 ||
97 	    (r = sshbuf_put_cstring(log_msg, func)) != 0 ||
98 	    (r = sshbuf_put_u32(log_msg, (u_int)line)) != 0 ||
99 	    (r = sshbuf_put_u32(log_msg, level)) != 0 ||
100 	    (r = sshbuf_put_cstring(log_msg, msg)) != 0)
101 		fatal_fr(r, "assemble");
102 	if ((len = sshbuf_len(log_msg)) < 4 || len > 0xffffffff)
103 		fatal_f("bad length %zu", len);
104 	POKE_U32(sshbuf_mutable_ptr(log_msg), len - 4);
105 	if (atomicio(vwrite, mon->m_log_sendfd,
106 	    sshbuf_mutable_ptr(log_msg), len) != len)
107 		fatal_f("write: %s", strerror(errno));
108 	sshbuf_free(log_msg);
109 }
110 
111 int
112 mm_is_monitor(void)
113 {
114 	/*
115 	 * m_pid is only set in the privileged part, and
116 	 * points to the unprivileged child.
117 	 */
118 	return (pmonitor && pmonitor->m_pid > 0);
119 }
120 
121 void
122 mm_request_send(int sock, enum monitor_reqtype type, struct sshbuf *m)
123 {
124 	size_t mlen = sshbuf_len(m);
125 	u_char buf[5];
126 
127 	debug3_f("entering, type %d", type);
128 
129 	if (mlen >= 0xffffffff)
130 		fatal_f("bad length %zu", mlen);
131 	POKE_U32(buf, mlen + 1);
132 	buf[4] = (u_char) type;		/* 1st byte of payload is mesg-type */
133 	if (atomicio(vwrite, sock, buf, sizeof(buf)) != sizeof(buf))
134 		fatal_f("write: %s", strerror(errno));
135 	if (atomicio(vwrite, sock, sshbuf_mutable_ptr(m), mlen) != mlen)
136 		fatal_f("write: %s", strerror(errno));
137 }
138 
139 void
140 mm_request_receive(int sock, struct sshbuf *m)
141 {
142 	u_char buf[4], *p = NULL;
143 	u_int msg_len;
144 	int r;
145 
146 	debug3_f("entering");
147 
148 	if (atomicio(read, sock, buf, sizeof(buf)) != sizeof(buf)) {
149 		if (errno == EPIPE)
150 			cleanup_exit(255);
151 		fatal_f("read: %s", strerror(errno));
152 	}
153 	msg_len = PEEK_U32(buf);
154 	if (msg_len > 256 * 1024)
155 		fatal_f("read: bad msg_len %d", msg_len);
156 	sshbuf_reset(m);
157 	if ((r = sshbuf_reserve(m, msg_len, &p)) != 0)
158 		fatal_fr(r, "reserve");
159 	if (atomicio(read, sock, p, msg_len) != msg_len)
160 		fatal_f("read: %s", strerror(errno));
161 }
162 
163 void
164 mm_request_receive_expect(int sock, enum monitor_reqtype type, struct sshbuf *m)
165 {
166 	u_char rtype;
167 	int r;
168 
169 	debug3_f("entering, type %d", type);
170 
171 	mm_request_receive(sock, m);
172 	if ((r = sshbuf_get_u8(m, &rtype)) != 0)
173 		fatal_fr(r, "parse");
174 	if (rtype != type)
175 		fatal_f("read: rtype %d != type %d", rtype, type);
176 }
177 
178 #ifdef WITH_OPENSSL
179 DH *
180 mm_choose_dh(int min, int nbits, int max)
181 {
182 	BIGNUM *p, *g;
183 	int r;
184 	u_char success = 0;
185 	struct sshbuf *m;
186 
187 	if ((m = sshbuf_new()) == NULL)
188 		fatal_f("sshbuf_new failed");
189 	if ((r = sshbuf_put_u32(m, min)) != 0 ||
190 	    (r = sshbuf_put_u32(m, nbits)) != 0 ||
191 	    (r = sshbuf_put_u32(m, max)) != 0)
192 		fatal_fr(r, "assemble");
193 
194 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_MODULI, m);
195 
196 	debug3_f("waiting for MONITOR_ANS_MODULI");
197 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_MODULI, m);
198 
199 	if ((r = sshbuf_get_u8(m, &success)) != 0)
200 		fatal_fr(r, "parse success");
201 	if (success == 0)
202 		fatal_f("MONITOR_ANS_MODULI failed");
203 
204 	if ((r = sshbuf_get_bignum2(m, &p)) != 0 ||
205 	    (r = sshbuf_get_bignum2(m, &g)) != 0)
206 		fatal_fr(r, "parse group");
207 
208 	debug3_f("remaining %zu", sshbuf_len(m));
209 	sshbuf_free(m);
210 
211 	return (dh_new_group(g, p));
212 }
213 #endif
214 
215 int
216 mm_sshkey_sign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp,
217     const u_char *data, size_t datalen, const char *hostkey_alg,
218     const char *sk_provider, const char *sk_pin, u_int compat)
219 {
220 	struct kex *kex = *pmonitor->m_pkex;
221 	struct sshbuf *m;
222 	u_int ndx = kex->host_key_index(key, 0, ssh);
223 	int r;
224 
225 	debug3_f("entering");
226 	if ((m = sshbuf_new()) == NULL)
227 		fatal_f("sshbuf_new failed");
228 	if ((r = sshbuf_put_u32(m, ndx)) != 0 ||
229 	    (r = sshbuf_put_string(m, data, datalen)) != 0 ||
230 	    (r = sshbuf_put_cstring(m, hostkey_alg)) != 0 ||
231 	    (r = sshbuf_put_u32(m, compat)) != 0)
232 		fatal_fr(r, "assemble");
233 
234 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SIGN, m);
235 
236 	debug3_f("waiting for MONITOR_ANS_SIGN");
237 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SIGN, m);
238 	if ((r = sshbuf_get_string(m, sigp, lenp)) != 0)
239 		fatal_fr(r, "parse");
240 	sshbuf_free(m);
241 
242 	return (0);
243 }
244 
245 struct passwd *
246 mm_getpwnamallow(struct ssh *ssh, const char *username)
247 {
248 	struct sshbuf *m;
249 	struct passwd *pw;
250 	size_t len;
251 	u_int i;
252 	ServerOptions *newopts;
253 	int r;
254 	u_char ok;
255 	const u_char *p;
256 
257 	debug3_f("entering");
258 
259 	if ((m = sshbuf_new()) == NULL)
260 		fatal_f("sshbuf_new failed");
261 	if ((r = sshbuf_put_cstring(m, username)) != 0)
262 		fatal_fr(r, "assemble");
263 
264 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PWNAM, m);
265 
266 	debug3_f("waiting for MONITOR_ANS_PWNAM");
267 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PWNAM, m);
268 
269 	if ((r = sshbuf_get_u8(m, &ok)) != 0)
270 		fatal_fr(r, "parse success");
271 	if (ok == 0) {
272 		pw = NULL;
273 		goto out;
274 	}
275 
276 	/* XXX don't like passing struct passwd like this */
277 	pw = xcalloc(sizeof(*pw), 1);
278 	if ((r = sshbuf_get_string_direct(m, &p, &len)) != 0)
279 		fatal_fr(r, "parse");
280 	if (len != sizeof(*pw))
281 		fatal_f("struct passwd size mismatch");
282 	memcpy(pw, p, sizeof(*pw));
283 
284 	if ((r = sshbuf_get_cstring(m, &pw->pw_name, NULL)) != 0 ||
285 	    (r = sshbuf_get_cstring(m, &pw->pw_passwd, NULL)) != 0 ||
286 	    (r = sshbuf_get_cstring(m, &pw->pw_gecos, NULL)) != 0 ||
287 	    (r = sshbuf_get_cstring(m, &pw->pw_class, NULL)) != 0 ||
288 	    (r = sshbuf_get_cstring(m, &pw->pw_dir, NULL)) != 0 ||
289 	    (r = sshbuf_get_cstring(m, &pw->pw_shell, NULL)) != 0)
290 		fatal_fr(r, "parse pw");
291 
292 out:
293 	/* copy options block as a Match directive may have changed some */
294 	if ((r = sshbuf_get_string_direct(m, &p, &len)) != 0)
295 		fatal_fr(r, "parse opts");
296 	if (len != sizeof(*newopts))
297 		fatal_f("option block size mismatch");
298 	newopts = xcalloc(sizeof(*newopts), 1);
299 	memcpy(newopts, p, sizeof(*newopts));
300 
301 #define M_CP_STROPT(x) do { \
302 		if (newopts->x != NULL && \
303 		    (r = sshbuf_get_cstring(m, &newopts->x, NULL)) != 0) \
304 			fatal_fr(r, "parse %s", #x); \
305 	} while (0)
306 #define M_CP_STRARRAYOPT(x, nx) do { \
307 		newopts->x = newopts->nx == 0 ? \
308 		    NULL : xcalloc(newopts->nx, sizeof(*newopts->x)); \
309 		for (i = 0; i < newopts->nx; i++) { \
310 			if ((r = sshbuf_get_cstring(m, \
311 			    &newopts->x[i], NULL)) != 0) \
312 				fatal_fr(r, "parse %s", #x); \
313 		} \
314 	} while (0)
315 	/* See comment in servconf.h */
316 	COPY_MATCH_STRING_OPTS();
317 #undef M_CP_STROPT
318 #undef M_CP_STRARRAYOPT
319 
320 	copy_set_server_options(&options, newopts, 1);
321 	log_change_level(options.log_level);
322 	log_verbose_reset();
323 	for (i = 0; i < options.num_log_verbose; i++)
324 		log_verbose_add(options.log_verbose[i]);
325 	process_permitopen(ssh, &options);
326 	free(newopts);
327 
328 	sshbuf_free(m);
329 
330 	return (pw);
331 }
332 
333 char *
334 mm_auth2_read_banner(void)
335 {
336 	struct sshbuf *m;
337 	char *banner;
338 	int r;
339 
340 	debug3_f("entering");
341 
342 	if ((m = sshbuf_new()) == NULL)
343 		fatal_f("sshbuf_new failed");
344 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTH2_READ_BANNER, m);
345 	sshbuf_reset(m);
346 
347 	mm_request_receive_expect(pmonitor->m_recvfd,
348 	    MONITOR_ANS_AUTH2_READ_BANNER, m);
349 	if ((r = sshbuf_get_cstring(m, &banner, NULL)) != 0)
350 		fatal_fr(r, "parse");
351 	sshbuf_free(m);
352 
353 	/* treat empty banner as missing banner */
354 	if (strlen(banner) == 0) {
355 		free(banner);
356 		banner = NULL;
357 	}
358 	return (banner);
359 }
360 
361 /* Inform the privileged process about service and style */
362 
363 void
364 mm_inform_authserv(char *service, char *style)
365 {
366 	struct sshbuf *m;
367 	int r;
368 
369 	debug3_f("entering");
370 
371 	if ((m = sshbuf_new()) == NULL)
372 		fatal_f("sshbuf_new failed");
373 	if ((r = sshbuf_put_cstring(m, service)) != 0 ||
374 	    (r = sshbuf_put_cstring(m, style ? style : "")) != 0)
375 		fatal_fr(r, "assemble");
376 
377 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, m);
378 
379 	sshbuf_free(m);
380 }
381 
382 /* Do the password authentication */
383 int
384 mm_auth_password(struct ssh *ssh, char *password)
385 {
386 	struct sshbuf *m;
387 	int r, authenticated = 0;
388 
389 	debug3_f("entering");
390 
391 	if ((m = sshbuf_new()) == NULL)
392 		fatal_f("sshbuf_new failed");
393 	if ((r = sshbuf_put_cstring(m, password)) != 0)
394 		fatal_fr(r, "assemble");
395 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHPASSWORD, m);
396 
397 	debug3_f("waiting for MONITOR_ANS_AUTHPASSWORD");
398 	mm_request_receive_expect(pmonitor->m_recvfd,
399 	    MONITOR_ANS_AUTHPASSWORD, m);
400 
401 	if ((r = sshbuf_get_u32(m, &authenticated)) != 0)
402 		fatal_fr(r, "parse");
403 
404 	sshbuf_free(m);
405 
406 	debug3_f("user %sauthenticated", authenticated ? "" : "not ");
407 	return (authenticated);
408 }
409 
410 int
411 mm_user_key_allowed(struct ssh *ssh, struct passwd *pw, struct sshkey *key,
412     int pubkey_auth_attempt, struct sshauthopt **authoptp)
413 {
414 	return (mm_key_allowed(MM_USERKEY, NULL, NULL, key,
415 	    pubkey_auth_attempt, authoptp));
416 }
417 
418 int
419 mm_hostbased_key_allowed(struct ssh *ssh, struct passwd *pw,
420     const char *user, const char *host, struct sshkey *key)
421 {
422 	return (mm_key_allowed(MM_HOSTKEY, user, host, key, 0, NULL));
423 }
424 
425 int
426 mm_key_allowed(enum mm_keytype type, const char *user, const char *host,
427     struct sshkey *key, int pubkey_auth_attempt, struct sshauthopt **authoptp)
428 {
429 	struct sshbuf *m;
430 	int r, allowed = 0;
431 	struct sshauthopt *opts = NULL;
432 
433 	debug3_f("entering");
434 
435 	if (authoptp != NULL)
436 		*authoptp = NULL;
437 
438 	if ((m = sshbuf_new()) == NULL)
439 		fatal_f("sshbuf_new failed");
440 	if ((r = sshbuf_put_u32(m, type)) != 0 ||
441 	    (r = sshbuf_put_cstring(m, user ? user : "")) != 0 ||
442 	    (r = sshbuf_put_cstring(m, host ? host : "")) != 0 ||
443 	    (r = sshkey_puts(key, m)) != 0 ||
444 	    (r = sshbuf_put_u32(m, pubkey_auth_attempt)) != 0)
445 		fatal_fr(r, "assemble");
446 
447 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYALLOWED, m);
448 
449 	debug3_f("waiting for MONITOR_ANS_KEYALLOWED");
450 	mm_request_receive_expect(pmonitor->m_recvfd,
451 	    MONITOR_ANS_KEYALLOWED, m);
452 
453 	if ((r = sshbuf_get_u32(m, &allowed)) != 0)
454 		fatal_fr(r, "parse");
455 	if (allowed && type == MM_USERKEY &&
456 	    (r = sshauthopt_deserialise(m, &opts)) != 0)
457 		fatal_fr(r, "sshauthopt_deserialise");
458 	sshbuf_free(m);
459 
460 	if (authoptp != NULL) {
461 		*authoptp = opts;
462 		opts = NULL;
463 	}
464 	sshauthopt_free(opts);
465 
466 	return allowed;
467 }
468 
469 /*
470  * This key verify needs to send the key type along, because the
471  * privileged parent makes the decision if the key is allowed
472  * for authentication.
473  */
474 
475 int
476 mm_sshkey_verify(const struct sshkey *key, const u_char *sig, size_t siglen,
477     const u_char *data, size_t datalen, const char *sigalg, u_int compat,
478     struct sshkey_sig_details **sig_detailsp)
479 {
480 	struct sshbuf *m;
481 	u_int encoded_ret = 0;
482 	int r;
483 	u_char sig_details_present, flags;
484 	u_int counter;
485 
486 	debug3_f("entering");
487 
488 	if (sig_detailsp != NULL)
489 		*sig_detailsp = NULL;
490 	if ((m = sshbuf_new()) == NULL)
491 		fatal_f("sshbuf_new failed");
492 	if ((r = sshkey_puts(key, m)) != 0 ||
493 	    (r = sshbuf_put_string(m, sig, siglen)) != 0 ||
494 	    (r = sshbuf_put_string(m, data, datalen)) != 0 ||
495 	    (r = sshbuf_put_cstring(m, sigalg == NULL ? "" : sigalg)) != 0)
496 		fatal_fr(r, "assemble");
497 
498 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYVERIFY, m);
499 
500 	debug3_f("waiting for MONITOR_ANS_KEYVERIFY");
501 	mm_request_receive_expect(pmonitor->m_recvfd,
502 	    MONITOR_ANS_KEYVERIFY, m);
503 
504 	if ((r = sshbuf_get_u32(m, &encoded_ret)) != 0 ||
505 	    (r = sshbuf_get_u8(m, &sig_details_present)) != 0)
506 		fatal_fr(r, "parse");
507 	if (sig_details_present && encoded_ret == 0) {
508 		if ((r = sshbuf_get_u32(m, &counter)) != 0 ||
509 		    (r = sshbuf_get_u8(m, &flags)) != 0)
510 			fatal_fr(r, "parse sig_details");
511 		if (sig_detailsp != NULL) {
512 			*sig_detailsp = xcalloc(1, sizeof(**sig_detailsp));
513 			(*sig_detailsp)->sk_counter = counter;
514 			(*sig_detailsp)->sk_flags = flags;
515 		}
516 	}
517 
518 	sshbuf_free(m);
519 
520 	if (encoded_ret != 0)
521 		return SSH_ERR_SIGNATURE_INVALID;
522 	return 0;
523 }
524 
525 void
526 mm_send_keystate(struct ssh *ssh, struct monitor *monitor)
527 {
528 	struct sshbuf *m;
529 	int r;
530 
531 	if ((m = sshbuf_new()) == NULL)
532 		fatal_f("sshbuf_new failed");
533 	if ((r = ssh_packet_get_state(ssh, m)) != 0)
534 		fatal_fr(r, "ssh_packet_get_state");
535 	mm_request_send(monitor->m_recvfd, MONITOR_REQ_KEYEXPORT, m);
536 	debug3_f("Finished sending state");
537 	sshbuf_free(m);
538 }
539 
540 int
541 mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
542 {
543 	struct sshbuf *m;
544 	char *p, *msg;
545 	int success = 0, tmp1 = -1, tmp2 = -1, r;
546 
547 	/* Kludge: ensure there are fds free to receive the pty/tty */
548 	if ((tmp1 = dup(pmonitor->m_recvfd)) == -1 ||
549 	    (tmp2 = dup(pmonitor->m_recvfd)) == -1) {
550 		error_f("cannot allocate fds for pty");
551 		if (tmp1 > 0)
552 			close(tmp1);
553 		if (tmp2 > 0)
554 			close(tmp2);
555 		return 0;
556 	}
557 	close(tmp1);
558 	close(tmp2);
559 
560 	if ((m = sshbuf_new()) == NULL)
561 		fatal_f("sshbuf_new failed");
562 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTY, m);
563 
564 	debug3_f("waiting for MONITOR_ANS_PTY");
565 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PTY, m);
566 
567 	if ((r = sshbuf_get_u32(m, &success)) != 0)
568 		fatal_fr(r, "parse success");
569 	if (success == 0) {
570 		debug3_f("pty alloc failed");
571 		sshbuf_free(m);
572 		return (0);
573 	}
574 	if ((r = sshbuf_get_cstring(m, &p, NULL)) != 0 ||
575 	    (r = sshbuf_get_cstring(m, &msg, NULL)) != 0)
576 		fatal_fr(r, "parse");
577 	sshbuf_free(m);
578 
579 	strlcpy(namebuf, p, namebuflen); /* Possible truncation */
580 	free(p);
581 
582 	if ((r = sshbuf_put(loginmsg, msg, strlen(msg))) != 0)
583 		fatal_fr(r, "put loginmsg");
584 	free(msg);
585 
586 	if ((*ptyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1 ||
587 	    (*ttyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1)
588 		fatal_f("receive fds failed");
589 
590 	/* Success */
591 	return (1);
592 }
593 
594 void
595 mm_session_pty_cleanup2(Session *s)
596 {
597 	struct sshbuf *m;
598 	int r;
599 
600 	if (s->ttyfd == -1)
601 		return;
602 	if ((m = sshbuf_new()) == NULL)
603 		fatal_f("sshbuf_new failed");
604 	if ((r = sshbuf_put_cstring(m, s->tty)) != 0)
605 		fatal_fr(r, "assmble");
606 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTYCLEANUP, m);
607 	sshbuf_free(m);
608 
609 	/* closed dup'ed master */
610 	if (s->ptymaster != -1 && close(s->ptymaster) == -1)
611 		error("close(s->ptymaster/%d): %s",
612 		    s->ptymaster, strerror(errno));
613 
614 	/* unlink pty from session */
615 	s->ttyfd = -1;
616 }
617 
618 /* Request process termination */
619 
620 void
621 mm_terminate(void)
622 {
623 	struct sshbuf *m;
624 
625 	if ((m = sshbuf_new()) == NULL)
626 		fatal_f("sshbuf_new failed");
627 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_TERM, m);
628 	sshbuf_free(m);
629 }
630 
631 static void
632 mm_chall_setup(char **name, char **infotxt, u_int *numprompts,
633     char ***prompts, u_int **echo_on)
634 {
635 	*name = xstrdup("");
636 	*infotxt = xstrdup("");
637 	*numprompts = 1;
638 	*prompts = xcalloc(*numprompts, sizeof(char *));
639 	*echo_on = xcalloc(*numprompts, sizeof(u_int));
640 	(*echo_on)[0] = 0;
641 }
642 
643 int
644 mm_bsdauth_query(void *ctx, char **name, char **infotxt,
645    u_int *numprompts, char ***prompts, u_int **echo_on)
646 {
647 	struct sshbuf *m;
648 	u_int success;
649 	char *challenge;
650 	int r;
651 
652 	debug3_f("entering");
653 
654 	if ((m = sshbuf_new()) == NULL)
655 		fatal_f("sshbuf_new failed");
656 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHQUERY, m);
657 
658 	mm_request_receive_expect(pmonitor->m_recvfd,
659 	    MONITOR_ANS_BSDAUTHQUERY, m);
660 	if ((r = sshbuf_get_u32(m, &success)) != 0)
661 		fatal_fr(r, "parse success");
662 	if (success == 0) {
663 		debug3_f("no challenge");
664 		sshbuf_free(m);
665 		return (-1);
666 	}
667 
668 	/* Get the challenge, and format the response */
669 	if ((r = sshbuf_get_cstring(m, &challenge, NULL)) != 0)
670 		fatal_fr(r, "parse challenge");
671 	sshbuf_free(m);
672 
673 	mm_chall_setup(name, infotxt, numprompts, prompts, echo_on);
674 	(*prompts)[0] = challenge;
675 
676 	debug3_f("received challenge: %s", challenge);
677 
678 	return (0);
679 }
680 
681 int
682 mm_bsdauth_respond(void *ctx, u_int numresponses, char **responses)
683 {
684 	struct sshbuf *m;
685 	int r, authok;
686 
687 	debug3_f("entering");
688 	if (numresponses != 1)
689 		return (-1);
690 
691 	if ((m = sshbuf_new()) == NULL)
692 		fatal_f("sshbuf_new failed");
693 	if ((r = sshbuf_put_cstring(m, responses[0])) != 0)
694 		fatal_fr(r, "assemble");
695 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHRESPOND, m);
696 
697 	mm_request_receive_expect(pmonitor->m_recvfd,
698 	    MONITOR_ANS_BSDAUTHRESPOND, m);
699 
700 	if ((r = sshbuf_get_u32(m, &authok)) != 0)
701 		fatal_fr(r, "parse");
702 	sshbuf_free(m);
703 
704 	return ((authok == 0) ? -1 : 0);
705 }
706 
707 #ifdef GSSAPI
708 OM_uint32
709 mm_ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID goid)
710 {
711 	struct sshbuf *m;
712 	OM_uint32 major;
713 	int r;
714 
715 	/* Client doesn't get to see the context */
716 	*ctx = NULL;
717 
718 	if ((m = sshbuf_new()) == NULL)
719 		fatal_f("sshbuf_new failed");
720 	if ((r = sshbuf_put_string(m, goid->elements, goid->length)) != 0)
721 		fatal_fr(r, "assemble");
722 
723 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSETUP, m);
724 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSETUP, m);
725 
726 	if ((r = sshbuf_get_u32(m, &major)) != 0)
727 		fatal_fr(r, "parse");
728 
729 	sshbuf_free(m);
730 	return (major);
731 }
732 
733 OM_uint32
734 mm_ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *in,
735     gss_buffer_desc *out, OM_uint32 *flagsp)
736 {
737 	struct sshbuf *m;
738 	OM_uint32 major;
739 	u_int flags;
740 	int r;
741 
742 	if ((m = sshbuf_new()) == NULL)
743 		fatal_f("sshbuf_new failed");
744 	if ((r = sshbuf_put_string(m, in->value, in->length)) != 0)
745 		fatal_fr(r, "assemble");
746 
747 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSTEP, m);
748 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSTEP, m);
749 
750 	if ((r = sshbuf_get_u32(m, &major)) != 0 ||
751 	    (r = ssh_gssapi_get_buffer_desc(m, out)) != 0)
752 		fatal_fr(r, "parse");
753 	if (flagsp != NULL) {
754 		if ((r = sshbuf_get_u32(m, &flags)) != 0)
755 			fatal_fr(r, "parse flags");
756 		*flagsp = flags;
757 	}
758 
759 	sshbuf_free(m);
760 
761 	return (major);
762 }
763 
764 OM_uint32
765 mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
766 {
767 	struct sshbuf *m;
768 	OM_uint32 major;
769 	int r;
770 
771 	if ((m = sshbuf_new()) == NULL)
772 		fatal_f("sshbuf_new failed");
773 	if ((r = sshbuf_put_string(m, gssbuf->value, gssbuf->length)) != 0 ||
774 	    (r = sshbuf_put_string(m, gssmic->value, gssmic->length)) != 0)
775 		fatal_fr(r, "assemble");
776 
777 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSCHECKMIC, m);
778 	mm_request_receive_expect(pmonitor->m_recvfd,
779 	    MONITOR_ANS_GSSCHECKMIC, m);
780 
781 	if ((r = sshbuf_get_u32(m, &major)) != 0)
782 		fatal_fr(r, "parse");
783 	sshbuf_free(m);
784 	return(major);
785 }
786 
787 int
788 mm_ssh_gssapi_userok(char *user)
789 {
790 	struct sshbuf *m;
791 	int r, authenticated = 0;
792 
793 	if ((m = sshbuf_new()) == NULL)
794 		fatal_f("sshbuf_new failed");
795 
796 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, m);
797 	mm_request_receive_expect(pmonitor->m_recvfd,
798 	    MONITOR_ANS_GSSUSEROK, m);
799 
800 	if ((r = sshbuf_get_u32(m, &authenticated)) != 0)
801 		fatal_fr(r, "parse");
802 
803 	sshbuf_free(m);
804 	debug3_f("user %sauthenticated", authenticated ? "" : "not ");
805 	return (authenticated);
806 }
807 #endif /* GSSAPI */
808