xref: /freebsd/crypto/openssh/sshd.c (revision 19261079b74319502c6ffa1249920079f0f69a72)
1 /* $OpenBSD: sshd.c,v 1.578 2021/07/19 02:21:50 dtucker Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5  *                    All rights reserved
6  * This program is the ssh daemon.  It listens for connections from clients,
7  * and performs authentication, executes use commands or shell, and forwards
8  * information to/from the application to the user client over an encrypted
9  * connection.  This can also handle forwarding of X11, TCP/IP, and
10  * authentication agent connections.
11  *
12  * As far as I am concerned, the code I have written for this software
13  * can be used freely for any purpose.  Any derived versions of this
14  * software must be clearly marked as such, and if the derived work is
15  * incompatible with the protocol description in the RFC file, it must be
16  * called by a name other than "ssh" or "Secure Shell".
17  *
18  * SSH2 implementation:
19  * Privilege Separation:
20  *
21  * Copyright (c) 2000, 2001, 2002 Markus Friedl.  All rights reserved.
22  * Copyright (c) 2002 Niels Provos.  All rights reserved.
23  *
24  * Redistribution and use in source and binary forms, with or without
25  * modification, are permitted provided that the following conditions
26  * are met:
27  * 1. Redistributions of source code must retain the above copyright
28  *    notice, this list of conditions and the following disclaimer.
29  * 2. Redistributions in binary form must reproduce the above copyright
30  *    notice, this list of conditions and the following disclaimer in the
31  *    documentation and/or other materials provided with the distribution.
32  *
33  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43  */
44 
45 #include "includes.h"
46 __RCSID("$FreeBSD$");
47 
48 #include <sys/types.h>
49 #include <sys/ioctl.h>
50 #include <sys/mman.h>
51 #include <sys/socket.h>
52 #ifdef HAVE_SYS_STAT_H
53 # include <sys/stat.h>
54 #endif
55 #ifdef HAVE_SYS_TIME_H
56 # include <sys/time.h>
57 #endif
58 #include "openbsd-compat/sys-tree.h"
59 #include "openbsd-compat/sys-queue.h"
60 #include <sys/wait.h>
61 
62 #include <errno.h>
63 #include <fcntl.h>
64 #include <netdb.h>
65 #ifdef HAVE_PATHS_H
66 #include <paths.h>
67 #endif
68 #include <grp.h>
69 #include <pwd.h>
70 #include <signal.h>
71 #include <stdarg.h>
72 #include <stdio.h>
73 #include <stdlib.h>
74 #include <string.h>
75 #include <unistd.h>
76 #include <limits.h>
77 
78 #ifdef WITH_OPENSSL
79 #include <openssl/dh.h>
80 #include <openssl/bn.h>
81 #include <openssl/rand.h>
82 #include "openbsd-compat/openssl-compat.h"
83 #endif
84 
85 #ifdef HAVE_SECUREWARE
86 #include <sys/security.h>
87 #include <prot.h>
88 #endif
89 
90 #ifdef __FreeBSD__
91 #include <resolv.h>
92 #if defined(GSSAPI) && defined(HAVE_GSSAPI_GSSAPI_H)
93 #include <gssapi/gssapi.h>
94 #elif defined(GSSAPI) && defined(HAVE_GSSAPI_H)
95 #include <gssapi.h>
96 #endif
97 #endif
98 
99 #include "xmalloc.h"
100 #include "ssh.h"
101 #include "ssh2.h"
102 #include "sshpty.h"
103 #include "packet.h"
104 #include "log.h"
105 #include "sshbuf.h"
106 #include "misc.h"
107 #include "match.h"
108 #include "servconf.h"
109 #include "uidswap.h"
110 #include "compat.h"
111 #include "cipher.h"
112 #include "digest.h"
113 #include "sshkey.h"
114 #include "kex.h"
115 #include "myproposal.h"
116 #include "authfile.h"
117 #include "pathnames.h"
118 #include "atomicio.h"
119 #include "canohost.h"
120 #include "hostfile.h"
121 #include "auth.h"
122 #include "authfd.h"
123 #include "msg.h"
124 #include "dispatch.h"
125 #include "channels.h"
126 #include "session.h"
127 #include "monitor.h"
128 #ifdef GSSAPI
129 #include "ssh-gss.h"
130 #endif
131 #include "monitor_wrap.h"
132 #include "ssh-sandbox.h"
133 #include "auth-options.h"
134 #include "version.h"
135 #include "ssherr.h"
136 #include "sk-api.h"
137 #include "srclimit.h"
138 #include "dh.h"
139 #include "blacklist_client.h"
140 
141 #ifdef LIBWRAP
142 #include <tcpd.h>
143 #include <syslog.h>
144 int allow_severity;
145 int deny_severity;
146 #endif /* LIBWRAP */
147 
148 /* Re-exec fds */
149 #define REEXEC_DEVCRYPTO_RESERVED_FD	(STDERR_FILENO + 1)
150 #define REEXEC_STARTUP_PIPE_FD		(STDERR_FILENO + 2)
151 #define REEXEC_CONFIG_PASS_FD		(STDERR_FILENO + 3)
152 #define REEXEC_MIN_FREE_FD		(STDERR_FILENO + 4)
153 
154 extern char *__progname;
155 
156 /* Server configuration options. */
157 ServerOptions options;
158 
159 /* Name of the server configuration file. */
160 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
161 
162 /*
163  * Debug mode flag.  This can be set on the command line.  If debug
164  * mode is enabled, extra debugging output will be sent to the system
165  * log, the daemon will not go to background, and will exit after processing
166  * the first connection.
167  */
168 int debug_flag = 0;
169 
170 /*
171  * Indicating that the daemon should only test the configuration and keys.
172  * If test_flag > 1 ("-T" flag), then sshd will also dump the effective
173  * configuration, optionally using connection information provided by the
174  * "-C" flag.
175  */
176 static int test_flag = 0;
177 
178 /* Flag indicating that the daemon is being started from inetd. */
179 static int inetd_flag = 0;
180 
181 /* Flag indicating that sshd should not detach and become a daemon. */
182 static int no_daemon_flag = 0;
183 
184 /* debug goes to stderr unless inetd_flag is set */
185 static int log_stderr = 0;
186 
187 /* Saved arguments to main(). */
188 static char **saved_argv;
189 static int saved_argc;
190 
191 /* re-exec */
192 static int rexeced_flag = 0;
193 static int rexec_flag = 1;
194 static int rexec_argc = 0;
195 static char **rexec_argv;
196 
197 /*
198  * The sockets that the server is listening; this is used in the SIGHUP
199  * signal handler.
200  */
201 #define	MAX_LISTEN_SOCKS	16
202 static int listen_socks[MAX_LISTEN_SOCKS];
203 static int num_listen_socks = 0;
204 
205 /* Daemon's agent connection */
206 int auth_sock = -1;
207 static int have_agent = 0;
208 
209 /*
210  * Any really sensitive data in the application is contained in this
211  * structure. The idea is that this structure could be locked into memory so
212  * that the pages do not get written into swap.  However, there are some
213  * problems. The private key contains BIGNUMs, and we do not (in principle)
214  * have access to the internals of them, and locking just the structure is
215  * not very useful.  Currently, memory locking is not implemented.
216  */
217 struct {
218 	struct sshkey	**host_keys;		/* all private host keys */
219 	struct sshkey	**host_pubkeys;		/* all public host keys */
220 	struct sshkey	**host_certificates;	/* all public host certificates */
221 	int		have_ssh2_key;
222 } sensitive_data;
223 
224 /* This is set to true when a signal is received. */
225 static volatile sig_atomic_t received_sighup = 0;
226 static volatile sig_atomic_t received_sigterm = 0;
227 
228 /* record remote hostname or ip */
229 u_int utmp_len = HOST_NAME_MAX+1;
230 
231 /*
232  * startup_pipes/flags are used for tracking children of the listening sshd
233  * process early in their lifespans. This tracking is needed for three things:
234  *
235  * 1) Implementing the MaxStartups limit of concurrent unauthenticated
236  *    connections.
237  * 2) Avoiding a race condition for SIGHUP processing, where child processes
238  *    may have listen_socks open that could collide with main listener process
239  *    after it restarts.
240  * 3) Ensuring that rexec'd sshd processes have received their initial state
241  *    from the parent listen process before handling SIGHUP.
242  *
243  * Child processes signal that they have completed closure of the listen_socks
244  * and (if applicable) received their rexec state by sending a char over their
245  * sock. Child processes signal that authentication has completed by closing
246  * the sock (or by exiting).
247  */
248 static int *startup_pipes = NULL;
249 static int *startup_flags = NULL;	/* Indicates child closed listener */
250 static int startup_pipe = -1;		/* in child */
251 
252 /* variables used for privilege separation */
253 int use_privsep = -1;
254 struct monitor *pmonitor = NULL;
255 int privsep_is_preauth = 1;
256 static int privsep_chroot = 1;
257 
258 /* global connection state and authentication contexts */
259 Authctxt *the_authctxt = NULL;
260 struct ssh *the_active_state;
261 
262 /* global key/cert auth options. XXX move to permanent ssh->authctxt? */
263 struct sshauthopt *auth_opts = NULL;
264 
265 /* sshd_config buffer */
266 struct sshbuf *cfg;
267 
268 /* Included files from the configuration file */
269 struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
270 
271 /* message to be displayed after login */
272 struct sshbuf *loginmsg;
273 
274 /* Unprivileged user */
275 struct passwd *privsep_pw = NULL;
276 
277 /* Prototypes for various functions defined later in this file. */
278 void destroy_sensitive_data(void);
279 void demote_sensitive_data(void);
280 static void do_ssh2_kex(struct ssh *);
281 
282 static char *listener_proctitle;
283 
284 /*
285  * Close all listening sockets
286  */
287 static void
288 close_listen_socks(void)
289 {
290 	int i;
291 
292 	for (i = 0; i < num_listen_socks; i++)
293 		close(listen_socks[i]);
294 	num_listen_socks = -1;
295 }
296 
297 static void
298 close_startup_pipes(void)
299 {
300 	int i;
301 
302 	if (startup_pipes)
303 		for (i = 0; i < options.max_startups; i++)
304 			if (startup_pipes[i] != -1)
305 				close(startup_pipes[i]);
306 }
307 
308 /*
309  * Signal handler for SIGHUP.  Sshd execs itself when it receives SIGHUP;
310  * the effect is to reread the configuration file (and to regenerate
311  * the server key).
312  */
313 
314 /*ARGSUSED*/
315 static void
316 sighup_handler(int sig)
317 {
318 	received_sighup = 1;
319 }
320 
321 /*
322  * Called from the main program after receiving SIGHUP.
323  * Restarts the server.
324  */
325 static void
326 sighup_restart(void)
327 {
328 	logit("Received SIGHUP; restarting.");
329 	if (options.pid_file != NULL)
330 		unlink(options.pid_file);
331 	platform_pre_restart();
332 	close_listen_socks();
333 	close_startup_pipes();
334 	ssh_signal(SIGHUP, SIG_IGN); /* will be restored after exec */
335 	execv(saved_argv[0], saved_argv);
336 	logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
337 	    strerror(errno));
338 	exit(1);
339 }
340 
341 /*
342  * Generic signal handler for terminating signals in the master daemon.
343  */
344 /*ARGSUSED*/
345 static void
346 sigterm_handler(int sig)
347 {
348 	received_sigterm = sig;
349 }
350 
351 /*
352  * SIGCHLD handler.  This is called whenever a child dies.  This will then
353  * reap any zombies left by exited children.
354  */
355 /*ARGSUSED*/
356 static void
357 main_sigchld_handler(int sig)
358 {
359 	int save_errno = errno;
360 	pid_t pid;
361 	int status;
362 
363 	while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
364 	    (pid == -1 && errno == EINTR))
365 		;
366 	errno = save_errno;
367 }
368 
369 /*
370  * Signal handler for the alarm after the login grace period has expired.
371  */
372 /*ARGSUSED*/
373 static void
374 grace_alarm_handler(int sig)
375 {
376 	if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
377 		kill(pmonitor->m_pid, SIGALRM);
378 
379 	/*
380 	 * Try to kill any processes that we have spawned, E.g. authorized
381 	 * keys command helpers.
382 	 */
383 	if (getpgid(0) == getpid()) {
384 		ssh_signal(SIGTERM, SIG_IGN);
385 		kill(0, SIGTERM);
386 	}
387 
388 	BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
389 
390 	/* Log error and exit. */
391 	if (use_privsep && pmonitor != NULL && pmonitor->m_pid <= 0)
392 		cleanup_exit(255); /* don't log in privsep child */
393 	else {
394 		sigdie("Timeout before authentication for %s port %d",
395 		    ssh_remote_ipaddr(the_active_state),
396 		    ssh_remote_port(the_active_state));
397 	}
398 }
399 
400 /* Destroy the host and server keys.  They will no longer be needed. */
401 void
402 destroy_sensitive_data(void)
403 {
404 	u_int i;
405 
406 	for (i = 0; i < options.num_host_key_files; i++) {
407 		if (sensitive_data.host_keys[i]) {
408 			sshkey_free(sensitive_data.host_keys[i]);
409 			sensitive_data.host_keys[i] = NULL;
410 		}
411 		if (sensitive_data.host_certificates[i]) {
412 			sshkey_free(sensitive_data.host_certificates[i]);
413 			sensitive_data.host_certificates[i] = NULL;
414 		}
415 	}
416 }
417 
418 /* Demote private to public keys for network child */
419 void
420 demote_sensitive_data(void)
421 {
422 	struct sshkey *tmp;
423 	u_int i;
424 	int r;
425 
426 	for (i = 0; i < options.num_host_key_files; i++) {
427 		if (sensitive_data.host_keys[i]) {
428 			if ((r = sshkey_from_private(
429 			    sensitive_data.host_keys[i], &tmp)) != 0)
430 				fatal_r(r, "could not demote host %s key",
431 				    sshkey_type(sensitive_data.host_keys[i]));
432 			sshkey_free(sensitive_data.host_keys[i]);
433 			sensitive_data.host_keys[i] = tmp;
434 		}
435 		/* Certs do not need demotion */
436 	}
437 }
438 
439 static void
440 reseed_prngs(void)
441 {
442 	u_int32_t rnd[256];
443 
444 #ifdef WITH_OPENSSL
445 	RAND_poll();
446 #endif
447 	arc4random_stir(); /* noop on recent arc4random() implementations */
448 	arc4random_buf(rnd, sizeof(rnd)); /* let arc4random notice PID change */
449 
450 #ifdef WITH_OPENSSL
451 	RAND_seed(rnd, sizeof(rnd));
452 	/* give libcrypto a chance to notice the PID change */
453 	if ((RAND_bytes((u_char *)rnd, 1)) != 1)
454 		fatal("%s: RAND_bytes failed", __func__);
455 #endif
456 
457 	explicit_bzero(rnd, sizeof(rnd));
458 }
459 
460 static void
461 privsep_preauth_child(void)
462 {
463 	gid_t gidset[1];
464 
465 	/* Enable challenge-response authentication for privilege separation */
466 	privsep_challenge_enable();
467 
468 #ifdef GSSAPI
469 	/* Cache supported mechanism OIDs for later use */
470 	ssh_gssapi_prepare_supported_oids();
471 #endif
472 
473 	reseed_prngs();
474 
475 	/* Demote the private keys to public keys. */
476 	demote_sensitive_data();
477 
478 	/* Demote the child */
479 	if (privsep_chroot) {
480 		/* Change our root directory */
481 		if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
482 			fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
483 			    strerror(errno));
484 		if (chdir("/") == -1)
485 			fatal("chdir(\"/\"): %s", strerror(errno));
486 
487 		/* Drop our privileges */
488 		debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
489 		    (u_int)privsep_pw->pw_gid);
490 		gidset[0] = privsep_pw->pw_gid;
491 		if (setgroups(1, gidset) == -1)
492 			fatal("setgroups: %.100s", strerror(errno));
493 		permanently_set_uid(privsep_pw);
494 	}
495 }
496 
497 static int
498 privsep_preauth(struct ssh *ssh)
499 {
500 	int status, r;
501 	pid_t pid;
502 	struct ssh_sandbox *box = NULL;
503 
504 	/* Set up unprivileged child process to deal with network data */
505 	pmonitor = monitor_init();
506 	/* Store a pointer to the kex for later rekeying */
507 	pmonitor->m_pkex = &ssh->kex;
508 
509 	if (use_privsep == PRIVSEP_ON)
510 		box = ssh_sandbox_init(pmonitor);
511 	pid = fork();
512 	if (pid == -1) {
513 		fatal("fork of unprivileged child failed");
514 	} else if (pid != 0) {
515 		debug2("Network child is on pid %ld", (long)pid);
516 
517 		pmonitor->m_pid = pid;
518 		if (have_agent) {
519 			r = ssh_get_authentication_socket(&auth_sock);
520 			if (r != 0) {
521 				error_r(r, "Could not get agent socket");
522 				have_agent = 0;
523 			}
524 		}
525 		if (box != NULL)
526 			ssh_sandbox_parent_preauth(box, pid);
527 		monitor_child_preauth(ssh, pmonitor);
528 
529 		/* Wait for the child's exit status */
530 		while (waitpid(pid, &status, 0) == -1) {
531 			if (errno == EINTR)
532 				continue;
533 			pmonitor->m_pid = -1;
534 			fatal_f("waitpid: %s", strerror(errno));
535 		}
536 		privsep_is_preauth = 0;
537 		pmonitor->m_pid = -1;
538 		if (WIFEXITED(status)) {
539 			if (WEXITSTATUS(status) != 0)
540 				fatal_f("preauth child exited with status %d",
541 				    WEXITSTATUS(status));
542 		} else if (WIFSIGNALED(status))
543 			fatal_f("preauth child terminated by signal %d",
544 			    WTERMSIG(status));
545 		if (box != NULL)
546 			ssh_sandbox_parent_finish(box);
547 		return 1;
548 	} else {
549 		/* child */
550 		close(pmonitor->m_sendfd);
551 		close(pmonitor->m_log_recvfd);
552 
553 		/* Arrange for logging to be sent to the monitor */
554 		set_log_handler(mm_log_handler, pmonitor);
555 
556 		privsep_preauth_child();
557 		setproctitle("%s", "[net]");
558 		if (box != NULL)
559 			ssh_sandbox_child(box);
560 
561 		return 0;
562 	}
563 }
564 
565 static void
566 privsep_postauth(struct ssh *ssh, Authctxt *authctxt)
567 {
568 #ifdef DISABLE_FD_PASSING
569 	if (1) {
570 #else
571 	if (authctxt->pw->pw_uid == 0) {
572 #endif
573 		/* File descriptor passing is broken or root login */
574 		use_privsep = 0;
575 		goto skip;
576 	}
577 
578 	/* New socket pair */
579 	monitor_reinit(pmonitor);
580 
581 	pmonitor->m_pid = fork();
582 	if (pmonitor->m_pid == -1)
583 		fatal("fork of unprivileged child failed");
584 	else if (pmonitor->m_pid != 0) {
585 		verbose("User child is on pid %ld", (long)pmonitor->m_pid);
586 		sshbuf_reset(loginmsg);
587 		monitor_clear_keystate(ssh, pmonitor);
588 		monitor_child_postauth(ssh, pmonitor);
589 
590 		/* NEVERREACHED */
591 		exit(0);
592 	}
593 
594 	/* child */
595 
596 	close(pmonitor->m_sendfd);
597 	pmonitor->m_sendfd = -1;
598 
599 	/* Demote the private keys to public keys. */
600 	demote_sensitive_data();
601 
602 	reseed_prngs();
603 
604 	/* Drop privileges */
605 	do_setusercontext(authctxt->pw);
606 
607  skip:
608 	/* It is safe now to apply the key state */
609 	monitor_apply_keystate(ssh, pmonitor);
610 
611 	/*
612 	 * Tell the packet layer that authentication was successful, since
613 	 * this information is not part of the key state.
614 	 */
615 	ssh_packet_set_authenticated(ssh);
616 }
617 
618 static void
619 append_hostkey_type(struct sshbuf *b, const char *s)
620 {
621 	int r;
622 
623 	if (match_pattern_list(s, options.hostkeyalgorithms, 0) != 1) {
624 		debug3_f("%s key not permitted by HostkeyAlgorithms", s);
625 		return;
626 	}
627 	if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) > 0 ? "," : "", s)) != 0)
628 		fatal_fr(r, "sshbuf_putf");
629 }
630 
631 static char *
632 list_hostkey_types(void)
633 {
634 	struct sshbuf *b;
635 	struct sshkey *key;
636 	char *ret;
637 	u_int i;
638 
639 	if ((b = sshbuf_new()) == NULL)
640 		fatal_f("sshbuf_new failed");
641 	for (i = 0; i < options.num_host_key_files; i++) {
642 		key = sensitive_data.host_keys[i];
643 		if (key == NULL)
644 			key = sensitive_data.host_pubkeys[i];
645 		if (key == NULL)
646 			continue;
647 		switch (key->type) {
648 		case KEY_RSA:
649 			/* for RSA we also support SHA2 signatures */
650 			append_hostkey_type(b, "rsa-sha2-512");
651 			append_hostkey_type(b, "rsa-sha2-256");
652 			/* FALLTHROUGH */
653 		case KEY_DSA:
654 		case KEY_ECDSA:
655 		case KEY_ED25519:
656 		case KEY_ECDSA_SK:
657 		case KEY_ED25519_SK:
658 		case KEY_XMSS:
659 			append_hostkey_type(b, sshkey_ssh_name(key));
660 			break;
661 		}
662 		/* If the private key has a cert peer, then list that too */
663 		key = sensitive_data.host_certificates[i];
664 		if (key == NULL)
665 			continue;
666 		switch (key->type) {
667 		case KEY_RSA_CERT:
668 			/* for RSA we also support SHA2 signatures */
669 			append_hostkey_type(b,
670 			    "rsa-sha2-512-cert-v01@openssh.com");
671 			append_hostkey_type(b,
672 			    "rsa-sha2-256-cert-v01@openssh.com");
673 			/* FALLTHROUGH */
674 		case KEY_DSA_CERT:
675 		case KEY_ECDSA_CERT:
676 		case KEY_ED25519_CERT:
677 		case KEY_ECDSA_SK_CERT:
678 		case KEY_ED25519_SK_CERT:
679 		case KEY_XMSS_CERT:
680 			append_hostkey_type(b, sshkey_ssh_name(key));
681 			break;
682 		}
683 	}
684 	if ((ret = sshbuf_dup_string(b)) == NULL)
685 		fatal_f("sshbuf_dup_string failed");
686 	sshbuf_free(b);
687 	debug_f("%s", ret);
688 	return ret;
689 }
690 
691 static struct sshkey *
692 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
693 {
694 	u_int i;
695 	struct sshkey *key;
696 
697 	for (i = 0; i < options.num_host_key_files; i++) {
698 		switch (type) {
699 		case KEY_RSA_CERT:
700 		case KEY_DSA_CERT:
701 		case KEY_ECDSA_CERT:
702 		case KEY_ED25519_CERT:
703 		case KEY_ECDSA_SK_CERT:
704 		case KEY_ED25519_SK_CERT:
705 		case KEY_XMSS_CERT:
706 			key = sensitive_data.host_certificates[i];
707 			break;
708 		default:
709 			key = sensitive_data.host_keys[i];
710 			if (key == NULL && !need_private)
711 				key = sensitive_data.host_pubkeys[i];
712 			break;
713 		}
714 		if (key == NULL || key->type != type)
715 			continue;
716 		switch (type) {
717 		case KEY_ECDSA:
718 		case KEY_ECDSA_SK:
719 		case KEY_ECDSA_CERT:
720 		case KEY_ECDSA_SK_CERT:
721 			if (key->ecdsa_nid != nid)
722 				continue;
723 			/* FALLTHROUGH */
724 		default:
725 			return need_private ?
726 			    sensitive_data.host_keys[i] : key;
727 		}
728 	}
729 	return NULL;
730 }
731 
732 struct sshkey *
733 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
734 {
735 	return get_hostkey_by_type(type, nid, 0, ssh);
736 }
737 
738 struct sshkey *
739 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
740 {
741 	return get_hostkey_by_type(type, nid, 1, ssh);
742 }
743 
744 struct sshkey *
745 get_hostkey_by_index(int ind)
746 {
747 	if (ind < 0 || (u_int)ind >= options.num_host_key_files)
748 		return (NULL);
749 	return (sensitive_data.host_keys[ind]);
750 }
751 
752 struct sshkey *
753 get_hostkey_public_by_index(int ind, struct ssh *ssh)
754 {
755 	if (ind < 0 || (u_int)ind >= options.num_host_key_files)
756 		return (NULL);
757 	return (sensitive_data.host_pubkeys[ind]);
758 }
759 
760 int
761 get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
762 {
763 	u_int i;
764 
765 	for (i = 0; i < options.num_host_key_files; i++) {
766 		if (sshkey_is_cert(key)) {
767 			if (key == sensitive_data.host_certificates[i] ||
768 			    (compare && sensitive_data.host_certificates[i] &&
769 			    sshkey_equal(key,
770 			    sensitive_data.host_certificates[i])))
771 				return (i);
772 		} else {
773 			if (key == sensitive_data.host_keys[i] ||
774 			    (compare && sensitive_data.host_keys[i] &&
775 			    sshkey_equal(key, sensitive_data.host_keys[i])))
776 				return (i);
777 			if (key == sensitive_data.host_pubkeys[i] ||
778 			    (compare && sensitive_data.host_pubkeys[i] &&
779 			    sshkey_equal(key, sensitive_data.host_pubkeys[i])))
780 				return (i);
781 		}
782 	}
783 	return (-1);
784 }
785 
786 /* Inform the client of all hostkeys */
787 static void
788 notify_hostkeys(struct ssh *ssh)
789 {
790 	struct sshbuf *buf;
791 	struct sshkey *key;
792 	u_int i, nkeys;
793 	int r;
794 	char *fp;
795 
796 	/* Some clients cannot cope with the hostkeys message, skip those. */
797 	if (ssh->compat & SSH_BUG_HOSTKEYS)
798 		return;
799 
800 	if ((buf = sshbuf_new()) == NULL)
801 		fatal_f("sshbuf_new");
802 	for (i = nkeys = 0; i < options.num_host_key_files; i++) {
803 		key = get_hostkey_public_by_index(i, ssh);
804 		if (key == NULL || key->type == KEY_UNSPEC ||
805 		    sshkey_is_cert(key))
806 			continue;
807 		fp = sshkey_fingerprint(key, options.fingerprint_hash,
808 		    SSH_FP_DEFAULT);
809 		debug3_f("key %d: %s %s", i, sshkey_ssh_name(key), fp);
810 		free(fp);
811 		if (nkeys == 0) {
812 			/*
813 			 * Start building the request when we find the
814 			 * first usable key.
815 			 */
816 			if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
817 			    (r = sshpkt_put_cstring(ssh, "hostkeys-00@openssh.com")) != 0 ||
818 			    (r = sshpkt_put_u8(ssh, 0)) != 0) /* want reply */
819 				sshpkt_fatal(ssh, r, "%s: start request", __func__);
820 		}
821 		/* Append the key to the request */
822 		sshbuf_reset(buf);
823 		if ((r = sshkey_putb(key, buf)) != 0)
824 			fatal_fr(r, "couldn't put hostkey %d", i);
825 		if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
826 			sshpkt_fatal(ssh, r, "%s: append key", __func__);
827 		nkeys++;
828 	}
829 	debug3_f("sent %u hostkeys", nkeys);
830 	if (nkeys == 0)
831 		fatal_f("no hostkeys");
832 	if ((r = sshpkt_send(ssh)) != 0)
833 		sshpkt_fatal(ssh, r, "%s: send", __func__);
834 	sshbuf_free(buf);
835 }
836 
837 /*
838  * returns 1 if connection should be dropped, 0 otherwise.
839  * dropping starts at connection #max_startups_begin with a probability
840  * of (max_startups_rate/100). the probability increases linearly until
841  * all connections are dropped for startups > max_startups
842  */
843 static int
844 should_drop_connection(int startups)
845 {
846 	int p, r;
847 
848 	if (startups < options.max_startups_begin)
849 		return 0;
850 	if (startups >= options.max_startups)
851 		return 1;
852 	if (options.max_startups_rate == 100)
853 		return 1;
854 
855 	p  = 100 - options.max_startups_rate;
856 	p *= startups - options.max_startups_begin;
857 	p /= options.max_startups - options.max_startups_begin;
858 	p += options.max_startups_rate;
859 	r = arc4random_uniform(100);
860 
861 	debug_f("p %d, r %d", p, r);
862 	return (r < p) ? 1 : 0;
863 }
864 
865 /*
866  * Check whether connection should be accepted by MaxStartups.
867  * Returns 0 if the connection is accepted. If the connection is refused,
868  * returns 1 and attempts to send notification to client.
869  * Logs when the MaxStartups condition is entered or exited, and periodically
870  * while in that state.
871  */
872 static int
873 drop_connection(int sock, int startups, int notify_pipe)
874 {
875 	char *laddr, *raddr;
876 	const char msg[] = "Exceeded MaxStartups\r\n";
877 	static time_t last_drop, first_drop;
878 	static u_int ndropped;
879 	LogLevel drop_level = SYSLOG_LEVEL_VERBOSE;
880 	time_t now;
881 
882 	now = monotime();
883 	if (!should_drop_connection(startups) &&
884 	    srclimit_check_allow(sock, notify_pipe) == 1) {
885 		if (last_drop != 0 &&
886 		    startups < options.max_startups_begin - 1) {
887 			/* XXX maybe need better hysteresis here */
888 			logit("exited MaxStartups throttling after %s, "
889 			    "%u connections dropped",
890 			    fmt_timeframe(now - first_drop), ndropped);
891 			last_drop = 0;
892 		}
893 		return 0;
894 	}
895 
896 #define SSHD_MAXSTARTUPS_LOG_INTERVAL	(5 * 60)
897 	if (last_drop == 0) {
898 		error("beginning MaxStartups throttling");
899 		drop_level = SYSLOG_LEVEL_INFO;
900 		first_drop = now;
901 		ndropped = 0;
902 	} else if (last_drop + SSHD_MAXSTARTUPS_LOG_INTERVAL < now) {
903 		/* Periodic logs */
904 		error("in MaxStartups throttling for %s, "
905 		    "%u connections dropped",
906 		    fmt_timeframe(now - first_drop), ndropped + 1);
907 		drop_level = SYSLOG_LEVEL_INFO;
908 	}
909 	last_drop = now;
910 	ndropped++;
911 
912 	laddr = get_local_ipaddr(sock);
913 	raddr = get_peer_ipaddr(sock);
914 	do_log2(drop_level, "drop connection #%d from [%s]:%d on [%s]:%d "
915 	    "past MaxStartups", startups, raddr, get_peer_port(sock),
916 	    laddr, get_local_port(sock));
917 	free(laddr);
918 	free(raddr);
919 	/* best-effort notification to client */
920 	(void)write(sock, msg, sizeof(msg) - 1);
921 	return 1;
922 }
923 
924 static void
925 usage(void)
926 {
927 	if (options.version_addendum && *options.version_addendum != '\0')
928 		fprintf(stderr, "%s %s, %s\n",
929 		    SSH_RELEASE,
930 		    options.version_addendum, OPENSSL_VERSION_STRING);
931 	else
932 		fprintf(stderr, "%s, %s\n",
933 		    SSH_RELEASE, OPENSSL_VERSION_STRING);
934 	fprintf(stderr,
935 "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n"
936 "            [-E log_file] [-f config_file] [-g login_grace_time]\n"
937 "            [-h host_key_file] [-o option] [-p port] [-u len]\n"
938 	);
939 	exit(1);
940 }
941 
942 static void
943 send_rexec_state(int fd, struct sshbuf *conf)
944 {
945 	struct sshbuf *m = NULL, *inc = NULL;
946 	struct include_item *item = NULL;
947 	int r;
948 
949 	debug3_f("entering fd = %d config len %zu", fd,
950 	    sshbuf_len(conf));
951 
952 	if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
953 		fatal_f("sshbuf_new failed");
954 
955 	/* pack includes into a string */
956 	TAILQ_FOREACH(item, &includes, entry) {
957 		if ((r = sshbuf_put_cstring(inc, item->selector)) != 0 ||
958 		    (r = sshbuf_put_cstring(inc, item->filename)) != 0 ||
959 		    (r = sshbuf_put_stringb(inc, item->contents)) != 0)
960 			fatal_fr(r, "compose includes");
961 	}
962 
963 	/*
964 	 * Protocol from reexec master to child:
965 	 *	string	configuration
966 	 *	string	included_files[] {
967 	 *		string	selector
968 	 *		string	filename
969 	 *		string	contents
970 	 *	}
971 	 *	string	rng_seed (if required)
972 	 */
973 	if ((r = sshbuf_put_stringb(m, conf)) != 0 ||
974 	    (r = sshbuf_put_stringb(m, inc)) != 0)
975 		fatal_fr(r, "compose config");
976 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
977 	rexec_send_rng_seed(m);
978 #endif
979 	if (ssh_msg_send(fd, 0, m) == -1)
980 		error_f("ssh_msg_send failed");
981 
982 	sshbuf_free(m);
983 	sshbuf_free(inc);
984 
985 	debug3_f("done");
986 }
987 
988 static void
989 recv_rexec_state(int fd, struct sshbuf *conf)
990 {
991 	struct sshbuf *m, *inc;
992 	u_char *cp, ver;
993 	size_t len;
994 	int r;
995 	struct include_item *item;
996 
997 	debug3_f("entering fd = %d", fd);
998 
999 	if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
1000 		fatal_f("sshbuf_new failed");
1001 	if (ssh_msg_recv(fd, m) == -1)
1002 		fatal_f("ssh_msg_recv failed");
1003 	if ((r = sshbuf_get_u8(m, &ver)) != 0)
1004 		fatal_fr(r, "parse version");
1005 	if (ver != 0)
1006 		fatal_f("rexec version mismatch");
1007 	if ((r = sshbuf_get_string(m, &cp, &len)) != 0 ||
1008 	    (r = sshbuf_get_stringb(m, inc)) != 0)
1009 		fatal_fr(r, "parse config");
1010 
1011 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1012 	rexec_recv_rng_seed(m);
1013 #endif
1014 
1015 	if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
1016 		fatal_fr(r, "sshbuf_put");
1017 
1018 	while (sshbuf_len(inc) != 0) {
1019 		item = xcalloc(1, sizeof(*item));
1020 		if ((item->contents = sshbuf_new()) == NULL)
1021 			fatal_f("sshbuf_new failed");
1022 		if ((r = sshbuf_get_cstring(inc, &item->selector, NULL)) != 0 ||
1023 		    (r = sshbuf_get_cstring(inc, &item->filename, NULL)) != 0 ||
1024 		    (r = sshbuf_get_stringb(inc, item->contents)) != 0)
1025 			fatal_fr(r, "parse includes");
1026 		TAILQ_INSERT_TAIL(&includes, item, entry);
1027 	}
1028 
1029 	free(cp);
1030 	sshbuf_free(m);
1031 
1032 	debug3_f("done");
1033 }
1034 
1035 /* Accept a connection from inetd */
1036 static void
1037 server_accept_inetd(int *sock_in, int *sock_out)
1038 {
1039 	if (rexeced_flag) {
1040 		close(REEXEC_CONFIG_PASS_FD);
1041 		*sock_in = *sock_out = dup(STDIN_FILENO);
1042 	} else {
1043 		*sock_in = dup(STDIN_FILENO);
1044 		*sock_out = dup(STDOUT_FILENO);
1045 	}
1046 	/*
1047 	 * We intentionally do not close the descriptors 0, 1, and 2
1048 	 * as our code for setting the descriptors won't work if
1049 	 * ttyfd happens to be one of those.
1050 	 */
1051 	if (stdfd_devnull(1, 1, !log_stderr) == -1)
1052 		error_f("stdfd_devnull failed");
1053 	debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
1054 }
1055 
1056 /*
1057  * Listen for TCP connections
1058  */
1059 static void
1060 listen_on_addrs(struct listenaddr *la)
1061 {
1062 	int ret, listen_sock;
1063 	struct addrinfo *ai;
1064 	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1065 
1066 	for (ai = la->addrs; ai; ai = ai->ai_next) {
1067 		if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1068 			continue;
1069 		if (num_listen_socks >= MAX_LISTEN_SOCKS)
1070 			fatal("Too many listen sockets. "
1071 			    "Enlarge MAX_LISTEN_SOCKS");
1072 		if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
1073 		    ntop, sizeof(ntop), strport, sizeof(strport),
1074 		    NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1075 			error("getnameinfo failed: %.100s",
1076 			    ssh_gai_strerror(ret));
1077 			continue;
1078 		}
1079 		/* Create socket for listening. */
1080 		listen_sock = socket(ai->ai_family, ai->ai_socktype,
1081 		    ai->ai_protocol);
1082 		if (listen_sock == -1) {
1083 			/* kernel may not support ipv6 */
1084 			verbose("socket: %.100s", strerror(errno));
1085 			continue;
1086 		}
1087 		if (set_nonblock(listen_sock) == -1) {
1088 			close(listen_sock);
1089 			continue;
1090 		}
1091 		if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) {
1092 			verbose("socket: CLOEXEC: %s", strerror(errno));
1093 			close(listen_sock);
1094 			continue;
1095 		}
1096 		/* Socket options */
1097 		set_reuseaddr(listen_sock);
1098 		if (la->rdomain != NULL &&
1099 		    set_rdomain(listen_sock, la->rdomain) == -1) {
1100 			close(listen_sock);
1101 			continue;
1102 		}
1103 
1104 		/* Only communicate in IPv6 over AF_INET6 sockets. */
1105 		if (ai->ai_family == AF_INET6)
1106 			sock_set_v6only(listen_sock);
1107 
1108 		debug("Bind to port %s on %s.", strport, ntop);
1109 
1110 		/* Bind the socket to the desired port. */
1111 		if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) == -1) {
1112 			error("Bind to port %s on %s failed: %.200s.",
1113 			    strport, ntop, strerror(errno));
1114 			close(listen_sock);
1115 			continue;
1116 		}
1117 		listen_socks[num_listen_socks] = listen_sock;
1118 		num_listen_socks++;
1119 
1120 		/* Start listening on the port. */
1121 		if (listen(listen_sock, SSH_LISTEN_BACKLOG) == -1)
1122 			fatal("listen on [%s]:%s: %.100s",
1123 			    ntop, strport, strerror(errno));
1124 		logit("Server listening on %s port %s%s%s.",
1125 		    ntop, strport,
1126 		    la->rdomain == NULL ? "" : " rdomain ",
1127 		    la->rdomain == NULL ? "" : la->rdomain);
1128 	}
1129 }
1130 
1131 static void
1132 server_listen(void)
1133 {
1134 	u_int i;
1135 
1136 	/* Initialise per-source limit tracking. */
1137 	srclimit_init(options.max_startups, options.per_source_max_startups,
1138 	    options.per_source_masklen_ipv4, options.per_source_masklen_ipv6);
1139 
1140 	for (i = 0; i < options.num_listen_addrs; i++) {
1141 		listen_on_addrs(&options.listen_addrs[i]);
1142 		freeaddrinfo(options.listen_addrs[i].addrs);
1143 		free(options.listen_addrs[i].rdomain);
1144 		memset(&options.listen_addrs[i], 0,
1145 		    sizeof(options.listen_addrs[i]));
1146 	}
1147 	free(options.listen_addrs);
1148 	options.listen_addrs = NULL;
1149 	options.num_listen_addrs = 0;
1150 
1151 	if (!num_listen_socks)
1152 		fatal("Cannot bind any address.");
1153 }
1154 
1155 /*
1156  * The main TCP accept loop. Note that, for the non-debug case, returns
1157  * from this function are in a forked subprocess.
1158  */
1159 static void
1160 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1161 {
1162 	fd_set *fdset;
1163 	int i, j, ret, maxfd;
1164 	int ostartups = -1, startups = 0, listening = 0, lameduck = 0;
1165 	int startup_p[2] = { -1 , -1 };
1166 	char c = 0;
1167 	struct sockaddr_storage from;
1168 	socklen_t fromlen;
1169 	pid_t pid;
1170 	u_char rnd[256];
1171 	sigset_t nsigset, osigset;
1172 
1173 	/* setup fd set for accept */
1174 	fdset = NULL;
1175 	maxfd = 0;
1176 	for (i = 0; i < num_listen_socks; i++)
1177 		if (listen_socks[i] > maxfd)
1178 			maxfd = listen_socks[i];
1179 	/* pipes connected to unauthenticated child sshd processes */
1180 	startup_pipes = xcalloc(options.max_startups, sizeof(int));
1181 	startup_flags = xcalloc(options.max_startups, sizeof(int));
1182 	for (i = 0; i < options.max_startups; i++)
1183 		startup_pipes[i] = -1;
1184 
1185 	/*
1186 	 * Prepare signal mask that we use to block signals that might set
1187 	 * received_sigterm or received_sighup, so that we are guaranteed
1188 	 * to immediately wake up the pselect if a signal is received after
1189 	 * the flag is checked.
1190 	 */
1191 	sigemptyset(&nsigset);
1192 	sigaddset(&nsigset, SIGHUP);
1193 	sigaddset(&nsigset, SIGCHLD);
1194 	sigaddset(&nsigset, SIGTERM);
1195 	sigaddset(&nsigset, SIGQUIT);
1196 
1197 	/*
1198 	 * Stay listening for connections until the system crashes or
1199 	 * the daemon is killed with a signal.
1200 	 */
1201 	for (;;) {
1202 		sigprocmask(SIG_BLOCK, &nsigset, &osigset);
1203 		if (received_sigterm) {
1204 			logit("Received signal %d; terminating.",
1205 			    (int) received_sigterm);
1206 			close_listen_socks();
1207 			if (options.pid_file != NULL)
1208 				unlink(options.pid_file);
1209 			exit(received_sigterm == SIGTERM ? 0 : 255);
1210 		}
1211 		if (ostartups != startups) {
1212 			setproctitle("%s [listener] %d of %d-%d startups",
1213 			    listener_proctitle, startups,
1214 			    options.max_startups_begin, options.max_startups);
1215 			ostartups = startups;
1216 		}
1217 		if (received_sighup) {
1218 			if (!lameduck) {
1219 				debug("Received SIGHUP; waiting for children");
1220 				close_listen_socks();
1221 				lameduck = 1;
1222 			}
1223 			if (listening <= 0) {
1224 				sigprocmask(SIG_SETMASK, &osigset, NULL);
1225 				sighup_restart();
1226 			}
1227 		}
1228 		free(fdset);
1229 		fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1230 		    sizeof(fd_mask));
1231 
1232 		for (i = 0; i < num_listen_socks; i++)
1233 			FD_SET(listen_socks[i], fdset);
1234 		for (i = 0; i < options.max_startups; i++)
1235 			if (startup_pipes[i] != -1)
1236 				FD_SET(startup_pipes[i], fdset);
1237 
1238 		/* Wait until a connection arrives or a child exits. */
1239 		ret = pselect(maxfd+1, fdset, NULL, NULL, NULL, &osigset);
1240 		if (ret == -1 && errno != EINTR)
1241 			error("pselect: %.100s", strerror(errno));
1242 		sigprocmask(SIG_SETMASK, &osigset, NULL);
1243 		if (ret == -1)
1244 			continue;
1245 
1246 		for (i = 0; i < options.max_startups; i++) {
1247 			if (startup_pipes[i] == -1 ||
1248 			    !FD_ISSET(startup_pipes[i], fdset))
1249 				continue;
1250 			switch (read(startup_pipes[i], &c, sizeof(c))) {
1251 			case -1:
1252 				if (errno == EINTR || errno == EAGAIN)
1253 					continue;
1254 				if (errno != EPIPE) {
1255 					error_f("startup pipe %d (fd=%d): "
1256 					    "read %s", i, startup_pipes[i],
1257 					    strerror(errno));
1258 				}
1259 				/* FALLTHROUGH */
1260 			case 0:
1261 				/* child exited or completed auth */
1262 				close(startup_pipes[i]);
1263 				srclimit_done(startup_pipes[i]);
1264 				startup_pipes[i] = -1;
1265 				startups--;
1266 				if (startup_flags[i])
1267 					listening--;
1268 				break;
1269 			case 1:
1270 				/* child has finished preliminaries */
1271 				if (startup_flags[i]) {
1272 					listening--;
1273 					startup_flags[i] = 0;
1274 				}
1275 				break;
1276 			}
1277 		}
1278 		for (i = 0; i < num_listen_socks; i++) {
1279 			if (!FD_ISSET(listen_socks[i], fdset))
1280 				continue;
1281 			fromlen = sizeof(from);
1282 			*newsock = accept(listen_socks[i],
1283 			    (struct sockaddr *)&from, &fromlen);
1284 			if (*newsock == -1) {
1285 				if (errno != EINTR && errno != EWOULDBLOCK &&
1286 				    errno != ECONNABORTED && errno != EAGAIN)
1287 					error("accept: %.100s",
1288 					    strerror(errno));
1289 				if (errno == EMFILE || errno == ENFILE)
1290 					usleep(100 * 1000);
1291 				continue;
1292 			}
1293 			if (unset_nonblock(*newsock) == -1 ||
1294 			    pipe(startup_p) == -1)
1295 				continue;
1296 			if (drop_connection(*newsock, startups, startup_p[0])) {
1297 				close(*newsock);
1298 				close(startup_p[0]);
1299 				close(startup_p[1]);
1300 				continue;
1301 			}
1302 
1303 			if (rexec_flag && socketpair(AF_UNIX,
1304 			    SOCK_STREAM, 0, config_s) == -1) {
1305 				error("reexec socketpair: %s",
1306 				    strerror(errno));
1307 				close(*newsock);
1308 				close(startup_p[0]);
1309 				close(startup_p[1]);
1310 				continue;
1311 			}
1312 
1313 			for (j = 0; j < options.max_startups; j++)
1314 				if (startup_pipes[j] == -1) {
1315 					startup_pipes[j] = startup_p[0];
1316 					if (maxfd < startup_p[0])
1317 						maxfd = startup_p[0];
1318 					startups++;
1319 					startup_flags[j] = 1;
1320 					break;
1321 				}
1322 
1323 			/*
1324 			 * Got connection.  Fork a child to handle it, unless
1325 			 * we are in debugging mode.
1326 			 */
1327 			if (debug_flag) {
1328 				/*
1329 				 * In debugging mode.  Close the listening
1330 				 * socket, and start processing the
1331 				 * connection without forking.
1332 				 */
1333 				debug("Server will not fork when running in debugging mode.");
1334 				close_listen_socks();
1335 				*sock_in = *newsock;
1336 				*sock_out = *newsock;
1337 				close(startup_p[0]);
1338 				close(startup_p[1]);
1339 				startup_pipe = -1;
1340 				pid = getpid();
1341 				if (rexec_flag) {
1342 					send_rexec_state(config_s[0], cfg);
1343 					close(config_s[0]);
1344 				}
1345 				return;
1346 			}
1347 
1348 			/*
1349 			 * Normal production daemon.  Fork, and have
1350 			 * the child process the connection. The
1351 			 * parent continues listening.
1352 			 */
1353 			platform_pre_fork();
1354 			listening++;
1355 			if ((pid = fork()) == 0) {
1356 				/*
1357 				 * Child.  Close the listening and
1358 				 * max_startup sockets.  Start using
1359 				 * the accepted socket. Reinitialize
1360 				 * logging (since our pid has changed).
1361 				 * We return from this function to handle
1362 				 * the connection.
1363 				 */
1364 				platform_post_fork_child();
1365 				startup_pipe = startup_p[1];
1366 				close_startup_pipes();
1367 				close_listen_socks();
1368 				*sock_in = *newsock;
1369 				*sock_out = *newsock;
1370 				log_init(__progname,
1371 				    options.log_level,
1372 				    options.log_facility,
1373 				    log_stderr);
1374 				if (rexec_flag)
1375 					close(config_s[0]);
1376 				else {
1377 					/*
1378 					 * Signal parent that the preliminaries
1379 					 * for this child are complete. For the
1380 					 * re-exec case, this happens after the
1381 					 * child has received the rexec state
1382 					 * from the server.
1383 					 */
1384 					(void)atomicio(vwrite, startup_pipe,
1385 					    "\0", 1);
1386 				}
1387 				return;
1388 			}
1389 
1390 			/* Parent.  Stay in the loop. */
1391 			platform_post_fork_parent(pid);
1392 			if (pid == -1)
1393 				error("fork: %.100s", strerror(errno));
1394 			else
1395 				debug("Forked child %ld.", (long)pid);
1396 
1397 			close(startup_p[1]);
1398 
1399 			if (rexec_flag) {
1400 				close(config_s[1]);
1401 				send_rexec_state(config_s[0], cfg);
1402 				close(config_s[0]);
1403 			}
1404 			close(*newsock);
1405 
1406 			/*
1407 			 * Ensure that our random state differs
1408 			 * from that of the child
1409 			 */
1410 			arc4random_stir();
1411 			arc4random_buf(rnd, sizeof(rnd));
1412 #ifdef WITH_OPENSSL
1413 			RAND_seed(rnd, sizeof(rnd));
1414 			if ((RAND_bytes((u_char *)rnd, 1)) != 1)
1415 				fatal("%s: RAND_bytes failed", __func__);
1416 #endif
1417 			explicit_bzero(rnd, sizeof(rnd));
1418 		}
1419 	}
1420 }
1421 
1422 /*
1423  * If IP options are supported, make sure there are none (log and
1424  * return an error if any are found).  Basically we are worried about
1425  * source routing; it can be used to pretend you are somebody
1426  * (ip-address) you are not. That itself may be "almost acceptable"
1427  * under certain circumstances, but rhosts authentication is useless
1428  * if source routing is accepted. Notice also that if we just dropped
1429  * source routing here, the other side could use IP spoofing to do
1430  * rest of the interaction and could still bypass security.  So we
1431  * exit here if we detect any IP options.
1432  */
1433 static void
1434 check_ip_options(struct ssh *ssh)
1435 {
1436 #ifdef IP_OPTIONS
1437 	int sock_in = ssh_packet_get_connection_in(ssh);
1438 	struct sockaddr_storage from;
1439 	u_char opts[200];
1440 	socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
1441 	char text[sizeof(opts) * 3 + 1];
1442 
1443 	memset(&from, 0, sizeof(from));
1444 	if (getpeername(sock_in, (struct sockaddr *)&from,
1445 	    &fromlen) == -1)
1446 		return;
1447 	if (from.ss_family != AF_INET)
1448 		return;
1449 	/* XXX IPv6 options? */
1450 
1451 	if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
1452 	    &option_size) >= 0 && option_size != 0) {
1453 		text[0] = '\0';
1454 		for (i = 0; i < option_size; i++)
1455 			snprintf(text + i*3, sizeof(text) - i*3,
1456 			    " %2.2x", opts[i]);
1457 		fatal("Connection from %.100s port %d with IP opts: %.800s",
1458 		    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
1459 	}
1460 	return;
1461 #endif /* IP_OPTIONS */
1462 }
1463 
1464 /* Set the routing domain for this process */
1465 static void
1466 set_process_rdomain(struct ssh *ssh, const char *name)
1467 {
1468 #if defined(HAVE_SYS_SET_PROCESS_RDOMAIN)
1469 	if (name == NULL)
1470 		return; /* default */
1471 
1472 	if (strcmp(name, "%D") == 0) {
1473 		/* "expands" to routing domain of connection */
1474 		if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
1475 			return;
1476 	}
1477 	/* NB. We don't pass 'ssh' to sys_set_process_rdomain() */
1478 	return sys_set_process_rdomain(name);
1479 #elif defined(__OpenBSD__)
1480 	int rtable, ortable = getrtable();
1481 	const char *errstr;
1482 
1483 	if (name == NULL)
1484 		return; /* default */
1485 
1486 	if (strcmp(name, "%D") == 0) {
1487 		/* "expands" to routing domain of connection */
1488 		if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
1489 			return;
1490 	}
1491 
1492 	rtable = (int)strtonum(name, 0, 255, &errstr);
1493 	if (errstr != NULL) /* Shouldn't happen */
1494 		fatal("Invalid routing domain \"%s\": %s", name, errstr);
1495 	if (rtable != ortable && setrtable(rtable) != 0)
1496 		fatal("Unable to set routing domain %d: %s",
1497 		    rtable, strerror(errno));
1498 	debug_f("set routing domain %d (was %d)", rtable, ortable);
1499 #else /* defined(__OpenBSD__) */
1500 	fatal("Unable to set routing domain: not supported in this platform");
1501 #endif
1502 }
1503 
1504 static void
1505 accumulate_host_timing_secret(struct sshbuf *server_cfg,
1506     struct sshkey *key)
1507 {
1508 	static struct ssh_digest_ctx *ctx;
1509 	u_char *hash;
1510 	size_t len;
1511 	struct sshbuf *buf;
1512 	int r;
1513 
1514 	if (ctx == NULL && (ctx = ssh_digest_start(SSH_DIGEST_SHA512)) == NULL)
1515 		fatal_f("ssh_digest_start");
1516 	if (key == NULL) { /* finalize */
1517 		/* add server config in case we are using agent for host keys */
1518 		if (ssh_digest_update(ctx, sshbuf_ptr(server_cfg),
1519 		    sshbuf_len(server_cfg)) != 0)
1520 			fatal_f("ssh_digest_update");
1521 		len = ssh_digest_bytes(SSH_DIGEST_SHA512);
1522 		hash = xmalloc(len);
1523 		if (ssh_digest_final(ctx, hash, len) != 0)
1524 			fatal_f("ssh_digest_final");
1525 		options.timing_secret = PEEK_U64(hash);
1526 		freezero(hash, len);
1527 		ssh_digest_free(ctx);
1528 		ctx = NULL;
1529 		return;
1530 	}
1531 	if ((buf = sshbuf_new()) == NULL)
1532 		fatal_f("could not allocate buffer");
1533 	if ((r = sshkey_private_serialize(key, buf)) != 0)
1534 		fatal_fr(r, "decode key");
1535 	if (ssh_digest_update(ctx, sshbuf_ptr(buf), sshbuf_len(buf)) != 0)
1536 		fatal_f("ssh_digest_update");
1537 	sshbuf_reset(buf);
1538 	sshbuf_free(buf);
1539 }
1540 
1541 static char *
1542 prepare_proctitle(int ac, char **av)
1543 {
1544 	char *ret = NULL;
1545 	int i;
1546 
1547 	for (i = 0; i < ac; i++)
1548 		xextendf(&ret, " ", "%s", av[i]);
1549 	return ret;
1550 }
1551 
1552 /*
1553  * Main program for the daemon.
1554  */
1555 int
1556 main(int ac, char **av)
1557 {
1558 	struct ssh *ssh = NULL;
1559 	extern char *optarg;
1560 	extern int optind;
1561 	int r, opt, on = 1, already_daemon, remote_port;
1562 	int sock_in = -1, sock_out = -1, newsock = -1;
1563 	const char *remote_ip, *rdomain;
1564 	char *fp, *line, *laddr, *logfile = NULL;
1565 	int config_s[2] = { -1 , -1 };
1566 	u_int i, j;
1567 	u_int64_t ibytes, obytes;
1568 	mode_t new_umask;
1569 	struct sshkey *key;
1570 	struct sshkey *pubkey;
1571 	int keytype;
1572 	Authctxt *authctxt;
1573 	struct connection_info *connection_info = NULL;
1574 
1575 #ifdef HAVE_SECUREWARE
1576 	(void)set_auth_parameters(ac, av);
1577 #endif
1578 	__progname = ssh_get_progname(av[0]);
1579 
1580 	/* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
1581 	saved_argc = ac;
1582 	rexec_argc = ac;
1583 	saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
1584 	for (i = 0; (int)i < ac; i++)
1585 		saved_argv[i] = xstrdup(av[i]);
1586 	saved_argv[i] = NULL;
1587 
1588 #ifndef HAVE_SETPROCTITLE
1589 	/* Prepare for later setproctitle emulation */
1590 	compat_init_setproctitle(ac, av);
1591 	av = saved_argv;
1592 #endif
1593 
1594 	if (geteuid() == 0 && setgroups(0, NULL) == -1)
1595 		debug("setgroups(): %.200s", strerror(errno));
1596 
1597 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1598 	sanitise_stdfd();
1599 
1600 	seed_rng();
1601 
1602 	/* Initialize configuration options to their default values. */
1603 	initialize_server_options(&options);
1604 
1605 	/* Parse command-line arguments. */
1606 	while ((opt = getopt(ac, av,
1607 	    "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1608 		switch (opt) {
1609 		case '4':
1610 			options.address_family = AF_INET;
1611 			break;
1612 		case '6':
1613 			options.address_family = AF_INET6;
1614 			break;
1615 		case 'f':
1616 			config_file_name = optarg;
1617 			break;
1618 		case 'c':
1619 			servconf_add_hostcert("[command-line]", 0,
1620 			    &options, optarg);
1621 			break;
1622 		case 'd':
1623 			if (debug_flag == 0) {
1624 				debug_flag = 1;
1625 				options.log_level = SYSLOG_LEVEL_DEBUG1;
1626 			} else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1627 				options.log_level++;
1628 			break;
1629 		case 'D':
1630 			no_daemon_flag = 1;
1631 			break;
1632 		case 'E':
1633 			logfile = optarg;
1634 			/* FALLTHROUGH */
1635 		case 'e':
1636 			log_stderr = 1;
1637 			break;
1638 		case 'i':
1639 			inetd_flag = 1;
1640 			break;
1641 		case 'r':
1642 			rexec_flag = 0;
1643 			break;
1644 		case 'R':
1645 			rexeced_flag = 1;
1646 			inetd_flag = 1;
1647 			break;
1648 		case 'Q':
1649 			/* ignored */
1650 			break;
1651 		case 'q':
1652 			options.log_level = SYSLOG_LEVEL_QUIET;
1653 			break;
1654 		case 'b':
1655 			/* protocol 1, ignored */
1656 			break;
1657 		case 'p':
1658 			options.ports_from_cmdline = 1;
1659 			if (options.num_ports >= MAX_PORTS) {
1660 				fprintf(stderr, "too many ports.\n");
1661 				exit(1);
1662 			}
1663 			options.ports[options.num_ports++] = a2port(optarg);
1664 			if (options.ports[options.num_ports-1] <= 0) {
1665 				fprintf(stderr, "Bad port number.\n");
1666 				exit(1);
1667 			}
1668 			break;
1669 		case 'g':
1670 			if ((options.login_grace_time = convtime(optarg)) == -1) {
1671 				fprintf(stderr, "Invalid login grace time.\n");
1672 				exit(1);
1673 			}
1674 			break;
1675 		case 'k':
1676 			/* protocol 1, ignored */
1677 			break;
1678 		case 'h':
1679 			servconf_add_hostkey("[command-line]", 0,
1680 			    &options, optarg, 1);
1681 			break;
1682 		case 't':
1683 			test_flag = 1;
1684 			break;
1685 		case 'T':
1686 			test_flag = 2;
1687 			break;
1688 		case 'C':
1689 			connection_info = get_connection_info(ssh, 0, 0);
1690 			if (parse_server_match_testspec(connection_info,
1691 			    optarg) == -1)
1692 				exit(1);
1693 			break;
1694 		case 'u':
1695 			utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1696 			if (utmp_len > HOST_NAME_MAX+1) {
1697 				fprintf(stderr, "Invalid utmp length.\n");
1698 				exit(1);
1699 			}
1700 			break;
1701 		case 'o':
1702 			line = xstrdup(optarg);
1703 			if (process_server_config_line(&options, line,
1704 			    "command-line", 0, NULL, NULL, &includes) != 0)
1705 				exit(1);
1706 			free(line);
1707 			break;
1708 		case '?':
1709 		default:
1710 			usage();
1711 			break;
1712 		}
1713 	}
1714 	if (rexeced_flag || inetd_flag)
1715 		rexec_flag = 0;
1716 	if (!test_flag && rexec_flag && !path_absolute(av[0]))
1717 		fatal("sshd re-exec requires execution with an absolute path");
1718 	if (rexeced_flag)
1719 		closefrom(REEXEC_MIN_FREE_FD);
1720 	else
1721 		closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1722 
1723 	/* If requested, redirect the logs to the specified logfile. */
1724 	if (logfile != NULL)
1725 		log_redirect_stderr_to(logfile);
1726 	/*
1727 	 * Force logging to stderr until we have loaded the private host
1728 	 * key (unless started from inetd)
1729 	 */
1730 	log_init(__progname,
1731 	    options.log_level == SYSLOG_LEVEL_NOT_SET ?
1732 	    SYSLOG_LEVEL_INFO : options.log_level,
1733 	    options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1734 	    SYSLOG_FACILITY_AUTH : options.log_facility,
1735 	    log_stderr || !inetd_flag || debug_flag);
1736 
1737 	/*
1738 	 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1739 	 * root's environment
1740 	 */
1741 	if (getenv("KRB5CCNAME") != NULL)
1742 		(void) unsetenv("KRB5CCNAME");
1743 
1744 	sensitive_data.have_ssh2_key = 0;
1745 
1746 	/*
1747 	 * If we're not doing an extended test do not silently ignore connection
1748 	 * test params.
1749 	 */
1750 	if (test_flag < 2 && connection_info != NULL)
1751 		fatal("Config test connection parameter (-C) provided without "
1752 		    "test mode (-T)");
1753 
1754 	/* Fetch our configuration */
1755 	if ((cfg = sshbuf_new()) == NULL)
1756 		fatal_f("sshbuf_new failed");
1757 	if (rexeced_flag) {
1758 		setproctitle("%s", "[rexeced]");
1759 		recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg);
1760 		if (!debug_flag) {
1761 			startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1762 			close(REEXEC_STARTUP_PIPE_FD);
1763 			/*
1764 			 * Signal parent that this child is at a point where
1765 			 * they can go away if they have a SIGHUP pending.
1766 			 */
1767 			(void)atomicio(vwrite, startup_pipe, "\0", 1);
1768 		}
1769 	} else if (strcasecmp(config_file_name, "none") != 0)
1770 		load_server_config(config_file_name, cfg);
1771 
1772 	parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1773 	    cfg, &includes, NULL);
1774 
1775 #ifdef WITH_OPENSSL
1776 	if (options.moduli_file != NULL)
1777 		dh_set_moduli_file(options.moduli_file);
1778 #endif
1779 
1780 	/* Fill in default values for those options not explicitly set. */
1781 	fill_default_server_options(&options);
1782 
1783 	/* Check that options are sensible */
1784 	if (options.authorized_keys_command_user == NULL &&
1785 	    (options.authorized_keys_command != NULL &&
1786 	    strcasecmp(options.authorized_keys_command, "none") != 0))
1787 		fatal("AuthorizedKeysCommand set without "
1788 		    "AuthorizedKeysCommandUser");
1789 	if (options.authorized_principals_command_user == NULL &&
1790 	    (options.authorized_principals_command != NULL &&
1791 	    strcasecmp(options.authorized_principals_command, "none") != 0))
1792 		fatal("AuthorizedPrincipalsCommand set without "
1793 		    "AuthorizedPrincipalsCommandUser");
1794 
1795 	/*
1796 	 * Check whether there is any path through configured auth methods.
1797 	 * Unfortunately it is not possible to verify this generally before
1798 	 * daemonisation in the presence of Match block, but this catches
1799 	 * and warns for trivial misconfigurations that could break login.
1800 	 */
1801 	if (options.num_auth_methods != 0) {
1802 		for (i = 0; i < options.num_auth_methods; i++) {
1803 			if (auth2_methods_valid(options.auth_methods[i],
1804 			    1) == 0)
1805 				break;
1806 		}
1807 		if (i >= options.num_auth_methods)
1808 			fatal("AuthenticationMethods cannot be satisfied by "
1809 			    "enabled authentication methods");
1810 	}
1811 
1812 	/* Check that there are no remaining arguments. */
1813 	if (optind < ac) {
1814 		fprintf(stderr, "Extra argument %s.\n", av[optind]);
1815 		exit(1);
1816 	}
1817 
1818 	debug("sshd version %s, %s", SSH_VERSION, SSH_OPENSSL_VERSION);
1819 
1820 	/* Store privilege separation user for later use if required. */
1821 	privsep_chroot = use_privsep && (getuid() == 0 || geteuid() == 0);
1822 	if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1823 		if (privsep_chroot || options.kerberos_authentication)
1824 			fatal("Privilege separation user %s does not exist",
1825 			    SSH_PRIVSEP_USER);
1826 	} else {
1827 		privsep_pw = pwcopy(privsep_pw);
1828 		freezero(privsep_pw->pw_passwd, strlen(privsep_pw->pw_passwd));
1829 		privsep_pw->pw_passwd = xstrdup("*");
1830 	}
1831 	endpwent();
1832 
1833 	/* load host keys */
1834 	sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1835 	    sizeof(struct sshkey *));
1836 	sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1837 	    sizeof(struct sshkey *));
1838 
1839 	if (options.host_key_agent) {
1840 		if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1841 			setenv(SSH_AUTHSOCKET_ENV_NAME,
1842 			    options.host_key_agent, 1);
1843 		if ((r = ssh_get_authentication_socket(NULL)) == 0)
1844 			have_agent = 1;
1845 		else
1846 			error_r(r, "Could not connect to agent \"%s\"",
1847 			    options.host_key_agent);
1848 	}
1849 
1850 	for (i = 0; i < options.num_host_key_files; i++) {
1851 		int ll = options.host_key_file_userprovided[i] ?
1852 		    SYSLOG_LEVEL_ERROR : SYSLOG_LEVEL_DEBUG1;
1853 
1854 		if (options.host_key_files[i] == NULL)
1855 			continue;
1856 		if ((r = sshkey_load_private(options.host_key_files[i], "",
1857 		    &key, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR)
1858 			do_log2_r(r, ll, "Unable to load host key \"%s\"",
1859 			    options.host_key_files[i]);
1860 		if (sshkey_is_sk(key) &&
1861 		    key->sk_flags & SSH_SK_USER_PRESENCE_REQD) {
1862 			debug("host key %s requires user presence, ignoring",
1863 			    options.host_key_files[i]);
1864 			key->sk_flags &= ~SSH_SK_USER_PRESENCE_REQD;
1865 		}
1866 		if (r == 0 && key != NULL &&
1867 		    (r = sshkey_shield_private(key)) != 0) {
1868 			do_log2_r(r, ll, "Unable to shield host key \"%s\"",
1869 			    options.host_key_files[i]);
1870 			sshkey_free(key);
1871 			key = NULL;
1872 		}
1873 		if ((r = sshkey_load_public(options.host_key_files[i],
1874 		    &pubkey, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR)
1875 			do_log2_r(r, ll, "Unable to load host key \"%s\"",
1876 			    options.host_key_files[i]);
1877 		if (pubkey != NULL && key != NULL) {
1878 			if (!sshkey_equal(pubkey, key)) {
1879 				error("Public key for %s does not match "
1880 				    "private key", options.host_key_files[i]);
1881 				sshkey_free(pubkey);
1882 				pubkey = NULL;
1883 			}
1884 		}
1885 		if (pubkey == NULL && key != NULL) {
1886 			if ((r = sshkey_from_private(key, &pubkey)) != 0)
1887 				fatal_r(r, "Could not demote key: \"%s\"",
1888 				    options.host_key_files[i]);
1889 		}
1890 		sensitive_data.host_keys[i] = key;
1891 		sensitive_data.host_pubkeys[i] = pubkey;
1892 
1893 		if (key == NULL && pubkey != NULL && have_agent) {
1894 			debug("will rely on agent for hostkey %s",
1895 			    options.host_key_files[i]);
1896 			keytype = pubkey->type;
1897 		} else if (key != NULL) {
1898 			keytype = key->type;
1899 			accumulate_host_timing_secret(cfg, key);
1900 		} else {
1901 			do_log2(ll, "Unable to load host key: %s",
1902 			    options.host_key_files[i]);
1903 			sensitive_data.host_keys[i] = NULL;
1904 			sensitive_data.host_pubkeys[i] = NULL;
1905 			continue;
1906 		}
1907 
1908 		switch (keytype) {
1909 		case KEY_RSA:
1910 		case KEY_DSA:
1911 		case KEY_ECDSA:
1912 		case KEY_ED25519:
1913 		case KEY_ECDSA_SK:
1914 		case KEY_ED25519_SK:
1915 		case KEY_XMSS:
1916 			if (have_agent || key != NULL)
1917 				sensitive_data.have_ssh2_key = 1;
1918 			break;
1919 		}
1920 		if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1921 		    SSH_FP_DEFAULT)) == NULL)
1922 			fatal("sshkey_fingerprint failed");
1923 		debug("%s host key #%d: %s %s",
1924 		    key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
1925 		free(fp);
1926 	}
1927 	accumulate_host_timing_secret(cfg, NULL);
1928 	if (!sensitive_data.have_ssh2_key) {
1929 		logit("sshd: no hostkeys available -- exiting.");
1930 		exit(1);
1931 	}
1932 
1933 	/*
1934 	 * Load certificates. They are stored in an array at identical
1935 	 * indices to the public keys that they relate to.
1936 	 */
1937 	sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1938 	    sizeof(struct sshkey *));
1939 	for (i = 0; i < options.num_host_key_files; i++)
1940 		sensitive_data.host_certificates[i] = NULL;
1941 
1942 	for (i = 0; i < options.num_host_cert_files; i++) {
1943 		if (options.host_cert_files[i] == NULL)
1944 			continue;
1945 		if ((r = sshkey_load_public(options.host_cert_files[i],
1946 		    &key, NULL)) != 0) {
1947 			error_r(r, "Could not load host certificate \"%s\"",
1948 			    options.host_cert_files[i]);
1949 			continue;
1950 		}
1951 		if (!sshkey_is_cert(key)) {
1952 			error("Certificate file is not a certificate: %s",
1953 			    options.host_cert_files[i]);
1954 			sshkey_free(key);
1955 			continue;
1956 		}
1957 		/* Find matching private key */
1958 		for (j = 0; j < options.num_host_key_files; j++) {
1959 			if (sshkey_equal_public(key,
1960 			    sensitive_data.host_pubkeys[j])) {
1961 				sensitive_data.host_certificates[j] = key;
1962 				break;
1963 			}
1964 		}
1965 		if (j >= options.num_host_key_files) {
1966 			error("No matching private key for certificate: %s",
1967 			    options.host_cert_files[i]);
1968 			sshkey_free(key);
1969 			continue;
1970 		}
1971 		sensitive_data.host_certificates[j] = key;
1972 		debug("host certificate: #%u type %d %s", j, key->type,
1973 		    sshkey_type(key));
1974 	}
1975 
1976 	if (privsep_chroot) {
1977 		struct stat st;
1978 
1979 		if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1980 		    (S_ISDIR(st.st_mode) == 0))
1981 			fatal("Missing privilege separation directory: %s",
1982 			    _PATH_PRIVSEP_CHROOT_DIR);
1983 
1984 #ifdef HAVE_CYGWIN
1985 		if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1986 		    (st.st_uid != getuid () ||
1987 		    (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1988 #else
1989 		if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1990 #endif
1991 			fatal("%s must be owned by root and not group or "
1992 			    "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1993 	}
1994 
1995 	if (test_flag > 1) {
1996 		/*
1997 		 * If no connection info was provided by -C then use
1998 		 * use a blank one that will cause no predicate to match.
1999 		 */
2000 		if (connection_info == NULL)
2001 			connection_info = get_connection_info(ssh, 0, 0);
2002 		connection_info->test = 1;
2003 		parse_server_match_config(&options, &includes, connection_info);
2004 		dump_config(&options);
2005 	}
2006 
2007 	/* Configuration looks good, so exit if in test mode. */
2008 	if (test_flag)
2009 		exit(0);
2010 
2011 	/*
2012 	 * Clear out any supplemental groups we may have inherited.  This
2013 	 * prevents inadvertent creation of files with bad modes (in the
2014 	 * portable version at least, it's certainly possible for PAM
2015 	 * to create a file, and we can't control the code in every
2016 	 * module which might be used).
2017 	 */
2018 	if (setgroups(0, NULL) < 0)
2019 		debug("setgroups() failed: %.200s", strerror(errno));
2020 
2021 	if (rexec_flag) {
2022 		if (rexec_argc < 0)
2023 			fatal("rexec_argc %d < 0", rexec_argc);
2024 		rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
2025 		for (i = 0; i < (u_int)rexec_argc; i++) {
2026 			debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
2027 			rexec_argv[i] = saved_argv[i];
2028 		}
2029 		rexec_argv[rexec_argc] = "-R";
2030 		rexec_argv[rexec_argc + 1] = NULL;
2031 	}
2032 	listener_proctitle = prepare_proctitle(ac, av);
2033 
2034 	/* Ensure that umask disallows at least group and world write */
2035 	new_umask = umask(0077) | 0022;
2036 	(void) umask(new_umask);
2037 
2038 	/* Initialize the log (it is reinitialized below in case we forked). */
2039 	if (debug_flag && (!inetd_flag || rexeced_flag))
2040 		log_stderr = 1;
2041 	log_init(__progname, options.log_level,
2042 	    options.log_facility, log_stderr);
2043 	for (i = 0; i < options.num_log_verbose; i++)
2044 		log_verbose_add(options.log_verbose[i]);
2045 
2046 	/*
2047 	 * If not in debugging mode, not started from inetd and not already
2048 	 * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
2049 	 * terminal, and fork.  The original process exits.
2050 	 */
2051 	already_daemon = daemonized();
2052 	if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
2053 
2054 		if (daemon(0, 0) == -1)
2055 			fatal("daemon() failed: %.200s", strerror(errno));
2056 
2057 		disconnect_controlling_tty();
2058 	}
2059 	/* Reinitialize the log (because of the fork above). */
2060 	log_init(__progname, options.log_level, options.log_facility, log_stderr);
2061 
2062 	/* Avoid killing the process in high-pressure swapping environments. */
2063 	if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0)
2064 		debug("madvise(): %.200s", strerror(errno));
2065 
2066 	/*
2067 	 * Chdir to the root directory so that the current disk can be
2068 	 * unmounted if desired.
2069 	 */
2070 	if (chdir("/") == -1)
2071 		error("chdir(\"/\"): %s", strerror(errno));
2072 
2073 	/* ignore SIGPIPE */
2074 	ssh_signal(SIGPIPE, SIG_IGN);
2075 
2076 	/* Get a connection, either from inetd or a listening TCP socket */
2077 	if (inetd_flag) {
2078 		server_accept_inetd(&sock_in, &sock_out);
2079 	} else {
2080 		platform_pre_listen();
2081 		server_listen();
2082 
2083 		ssh_signal(SIGHUP, sighup_handler);
2084 		ssh_signal(SIGCHLD, main_sigchld_handler);
2085 		ssh_signal(SIGTERM, sigterm_handler);
2086 		ssh_signal(SIGQUIT, sigterm_handler);
2087 
2088 		/*
2089 		 * Write out the pid file after the sigterm handler
2090 		 * is setup and the listen sockets are bound
2091 		 */
2092 		if (options.pid_file != NULL && !debug_flag) {
2093 			FILE *f = fopen(options.pid_file, "w");
2094 
2095 			if (f == NULL) {
2096 				error("Couldn't create pid file \"%s\": %s",
2097 				    options.pid_file, strerror(errno));
2098 			} else {
2099 				fprintf(f, "%ld\n", (long) getpid());
2100 				fclose(f);
2101 			}
2102 		}
2103 
2104 		/* Accept a connection and return in a forked child */
2105 		server_accept_loop(&sock_in, &sock_out,
2106 		    &newsock, config_s);
2107 	}
2108 
2109 	/* This is the child processing a new connection. */
2110 	setproctitle("%s", "[accepted]");
2111 
2112 	/*
2113 	 * Create a new session and process group since the 4.4BSD
2114 	 * setlogin() affects the entire process group.  We don't
2115 	 * want the child to be able to affect the parent.
2116 	 */
2117 #if !defined(SSHD_ACQUIRES_CTTY)
2118 	/*
2119 	 * If setsid is called, on some platforms sshd will later acquire a
2120 	 * controlling terminal which will result in "could not set
2121 	 * controlling tty" errors.
2122 	 */
2123 	if (!debug_flag && !inetd_flag && setsid() == -1)
2124 		error("setsid: %.100s", strerror(errno));
2125 #endif
2126 
2127 	if (rexec_flag) {
2128 		debug("rexec start in %d out %d newsock %d pipe %d sock %d",
2129 		    sock_in, sock_out, newsock, startup_pipe, config_s[0]);
2130 		dup2(newsock, STDIN_FILENO);
2131 		dup2(STDIN_FILENO, STDOUT_FILENO);
2132 		if (startup_pipe == -1)
2133 			close(REEXEC_STARTUP_PIPE_FD);
2134 		else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
2135 			dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
2136 			close(startup_pipe);
2137 			startup_pipe = REEXEC_STARTUP_PIPE_FD;
2138 		}
2139 
2140 		dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
2141 		close(config_s[1]);
2142 
2143 		ssh_signal(SIGHUP, SIG_IGN); /* avoid reset to SIG_DFL */
2144 		execv(rexec_argv[0], rexec_argv);
2145 
2146 		/* Reexec has failed, fall back and continue */
2147 		error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
2148 		recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
2149 		log_init(__progname, options.log_level,
2150 		    options.log_facility, log_stderr);
2151 
2152 		/* Clean up fds */
2153 		close(REEXEC_CONFIG_PASS_FD);
2154 		newsock = sock_out = sock_in = dup(STDIN_FILENO);
2155 		if (stdfd_devnull(1, 1, 0) == -1)
2156 			error_f("stdfd_devnull failed");
2157 		debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
2158 		    sock_in, sock_out, newsock, startup_pipe, config_s[0]);
2159 	}
2160 
2161 	/* Executed child processes don't need these. */
2162 	fcntl(sock_out, F_SETFD, FD_CLOEXEC);
2163 	fcntl(sock_in, F_SETFD, FD_CLOEXEC);
2164 
2165 	/* We will not restart on SIGHUP since it no longer makes sense. */
2166 	ssh_signal(SIGALRM, SIG_DFL);
2167 	ssh_signal(SIGHUP, SIG_DFL);
2168 	ssh_signal(SIGTERM, SIG_DFL);
2169 	ssh_signal(SIGQUIT, SIG_DFL);
2170 	ssh_signal(SIGCHLD, SIG_DFL);
2171 	ssh_signal(SIGINT, SIG_DFL);
2172 
2173 #ifdef __FreeBSD__
2174 	/*
2175 	 * Initialize the resolver.  This may not happen automatically
2176 	 * before privsep chroot().
2177 	 */
2178 	if ((_res.options & RES_INIT) == 0) {
2179 		debug("res_init()");
2180 		res_init();
2181 	}
2182 #ifdef GSSAPI
2183 	/*
2184 	 * Force GSS-API to parse its configuration and load any
2185 	 * mechanism plugins.
2186 	 */
2187 	{
2188 		gss_OID_set mechs;
2189 		OM_uint32 minor_status;
2190 		gss_indicate_mechs(&minor_status, &mechs);
2191 		gss_release_oid_set(&minor_status, &mechs);
2192 	}
2193 #endif
2194 #endif
2195 
2196 	/*
2197 	 * Register our connection.  This turns encryption off because we do
2198 	 * not have a key.
2199 	 */
2200 	if ((ssh = ssh_packet_set_connection(NULL, sock_in, sock_out)) == NULL)
2201 		fatal("Unable to create connection");
2202 	the_active_state = ssh;
2203 	ssh_packet_set_server(ssh);
2204 
2205 	check_ip_options(ssh);
2206 
2207 	/* Prepare the channels layer */
2208 	channel_init_channels(ssh);
2209 	channel_set_af(ssh, options.address_family);
2210 	process_permitopen(ssh, &options);
2211 
2212 	/* Set SO_KEEPALIVE if requested. */
2213 	if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
2214 	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
2215 		error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
2216 
2217 	if ((remote_port = ssh_remote_port(ssh)) < 0) {
2218 		debug("ssh_remote_port failed");
2219 		cleanup_exit(255);
2220 	}
2221 
2222 	if (options.routing_domain != NULL)
2223 		set_process_rdomain(ssh, options.routing_domain);
2224 
2225 	/*
2226 	 * The rest of the code depends on the fact that
2227 	 * ssh_remote_ipaddr() caches the remote ip, even if
2228 	 * the socket goes away.
2229 	 */
2230 	remote_ip = ssh_remote_ipaddr(ssh);
2231 
2232 #ifdef HAVE_LOGIN_CAP
2233 	/* Also caches remote hostname for sandboxed child. */
2234 	auth_get_canonical_hostname(ssh, options.use_dns);
2235 #endif
2236 
2237 #ifdef SSH_AUDIT_EVENTS
2238 	audit_connection_from(remote_ip, remote_port);
2239 #endif
2240 #ifdef LIBWRAP
2241 	allow_severity = options.log_facility|LOG_INFO;
2242 	deny_severity = options.log_facility|LOG_WARNING;
2243 	/* Check whether logins are denied from this host. */
2244 	if (ssh_packet_connection_is_on_socket(ssh)) {
2245 		struct request_info req;
2246 
2247 		request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
2248 		fromhost(&req);
2249 
2250 		if (!hosts_access(&req)) {
2251 			debug("Connection refused by tcp wrapper");
2252 			refuse(&req);
2253 			/* NOTREACHED */
2254 			fatal("libwrap refuse returns");
2255 		}
2256 	}
2257 #endif /* LIBWRAP */
2258 
2259 	rdomain = ssh_packet_rdomain_in(ssh);
2260 
2261 	/* Log the connection. */
2262 	laddr = get_local_ipaddr(sock_in);
2263 	verbose("Connection from %s port %d on %s port %d%s%s%s",
2264 	    remote_ip, remote_port, laddr,  ssh_local_port(ssh),
2265 	    rdomain == NULL ? "" : " rdomain \"",
2266 	    rdomain == NULL ? "" : rdomain,
2267 	    rdomain == NULL ? "" : "\"");
2268 	free(laddr);
2269 
2270 	/*
2271 	 * We don't want to listen forever unless the other side
2272 	 * successfully authenticates itself.  So we set up an alarm which is
2273 	 * cleared after successful authentication.  A limit of zero
2274 	 * indicates no limit. Note that we don't set the alarm in debugging
2275 	 * mode; it is just annoying to have the server exit just when you
2276 	 * are about to discover the bug.
2277 	 */
2278 	ssh_signal(SIGALRM, grace_alarm_handler);
2279 	if (!debug_flag)
2280 		alarm(options.login_grace_time);
2281 
2282 	if ((r = kex_exchange_identification(ssh, -1,
2283 	    options.version_addendum)) != 0)
2284 		sshpkt_fatal(ssh, r, "banner exchange");
2285 
2286 	ssh_packet_set_nonblocking(ssh);
2287 
2288 	/* allocate authentication context */
2289 	authctxt = xcalloc(1, sizeof(*authctxt));
2290 	ssh->authctxt = authctxt;
2291 
2292 	authctxt->loginmsg = loginmsg;
2293 
2294 	/* XXX global for cleanup, access from other modules */
2295 	the_authctxt = authctxt;
2296 
2297 	/* Set default key authentication options */
2298 	if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL)
2299 		fatal("allocation failed");
2300 
2301 	/* prepare buffer to collect messages to display to user after login */
2302 	if ((loginmsg = sshbuf_new()) == NULL)
2303 		fatal_f("sshbuf_new failed");
2304 	auth_debug_reset();
2305 
2306 	BLACKLIST_INIT();
2307 
2308 	if (use_privsep) {
2309 		if (privsep_preauth(ssh) == 1)
2310 			goto authenticated;
2311 	} else if (have_agent) {
2312 		if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
2313 			error_r(r, "Unable to get agent socket");
2314 			have_agent = 0;
2315 		}
2316 	}
2317 
2318 	/* perform the key exchange */
2319 	/* authenticate user and start session */
2320 	do_ssh2_kex(ssh);
2321 	do_authentication2(ssh);
2322 
2323 	/*
2324 	 * If we use privilege separation, the unprivileged child transfers
2325 	 * the current keystate and exits
2326 	 */
2327 	if (use_privsep) {
2328 		mm_send_keystate(ssh, pmonitor);
2329 		ssh_packet_clear_keys(ssh);
2330 		exit(0);
2331 	}
2332 
2333  authenticated:
2334 	/*
2335 	 * Cancel the alarm we set to limit the time taken for
2336 	 * authentication.
2337 	 */
2338 	alarm(0);
2339 	ssh_signal(SIGALRM, SIG_DFL);
2340 	authctxt->authenticated = 1;
2341 	if (startup_pipe != -1) {
2342 		close(startup_pipe);
2343 		startup_pipe = -1;
2344 	}
2345 
2346 #ifdef SSH_AUDIT_EVENTS
2347 	audit_event(ssh, SSH_AUTH_SUCCESS);
2348 #endif
2349 
2350 #ifdef GSSAPI
2351 	if (options.gss_authentication) {
2352 		temporarily_use_uid(authctxt->pw);
2353 		ssh_gssapi_storecreds();
2354 		restore_uid();
2355 	}
2356 #endif
2357 #ifdef USE_PAM
2358 	if (options.use_pam) {
2359 		do_pam_setcred(1);
2360 		do_pam_session(ssh);
2361 	}
2362 #endif
2363 
2364 	/*
2365 	 * In privilege separation, we fork another child and prepare
2366 	 * file descriptor passing.
2367 	 */
2368 	if (use_privsep) {
2369 		privsep_postauth(ssh, authctxt);
2370 		/* the monitor process [priv] will not return */
2371 	}
2372 
2373 	ssh_packet_set_timeout(ssh, options.client_alive_interval,
2374 	    options.client_alive_count_max);
2375 
2376 	/* Try to send all our hostkeys to the client */
2377 	notify_hostkeys(ssh);
2378 
2379 	/* Start session. */
2380 	do_authenticated(ssh, authctxt);
2381 
2382 	/* The connection has been terminated. */
2383 	ssh_packet_get_bytes(ssh, &ibytes, &obytes);
2384 	verbose("Transferred: sent %llu, received %llu bytes",
2385 	    (unsigned long long)obytes, (unsigned long long)ibytes);
2386 
2387 	verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
2388 
2389 #ifdef USE_PAM
2390 	if (options.use_pam)
2391 		finish_pam();
2392 #endif /* USE_PAM */
2393 
2394 #ifdef SSH_AUDIT_EVENTS
2395 	PRIVSEP(audit_event(ssh, SSH_CONNECTION_CLOSE));
2396 #endif
2397 
2398 	ssh_packet_close(ssh);
2399 
2400 	if (use_privsep)
2401 		mm_terminate();
2402 
2403 	exit(0);
2404 }
2405 
2406 int
2407 sshd_hostkey_sign(struct ssh *ssh, struct sshkey *privkey,
2408     struct sshkey *pubkey, u_char **signature, size_t *slenp,
2409     const u_char *data, size_t dlen, const char *alg)
2410 {
2411 	int r;
2412 
2413 	if (use_privsep) {
2414 		if (privkey) {
2415 			if (mm_sshkey_sign(ssh, privkey, signature, slenp,
2416 			    data, dlen, alg, options.sk_provider, NULL,
2417 			    ssh->compat) < 0)
2418 				fatal_f("privkey sign failed");
2419 		} else {
2420 			if (mm_sshkey_sign(ssh, pubkey, signature, slenp,
2421 			    data, dlen, alg, options.sk_provider, NULL,
2422 			    ssh->compat) < 0)
2423 				fatal_f("pubkey sign failed");
2424 		}
2425 	} else {
2426 		if (privkey) {
2427 			if (sshkey_sign(privkey, signature, slenp, data, dlen,
2428 			    alg, options.sk_provider, NULL, ssh->compat) < 0)
2429 				fatal_f("privkey sign failed");
2430 		} else {
2431 			if ((r = ssh_agent_sign(auth_sock, pubkey,
2432 			    signature, slenp, data, dlen, alg,
2433 			    ssh->compat)) != 0) {
2434 				fatal_fr(r, "agent sign failed");
2435 			}
2436 		}
2437 	}
2438 	return 0;
2439 }
2440 
2441 /* SSH2 key exchange */
2442 static void
2443 do_ssh2_kex(struct ssh *ssh)
2444 {
2445 	char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
2446 	struct kex *kex;
2447 	int r;
2448 
2449 	myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(ssh,
2450 	    options.kex_algorithms);
2451 	myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(ssh,
2452 	    options.ciphers);
2453 	myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(ssh,
2454 	    options.ciphers);
2455 	myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2456 	    myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2457 
2458 	if (options.compression == COMP_NONE) {
2459 		myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2460 		    myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
2461 	}
2462 
2463 	if (options.rekey_limit || options.rekey_interval)
2464 		ssh_packet_set_rekey_limits(ssh, options.rekey_limit,
2465 		    options.rekey_interval);
2466 
2467 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2468 	    ssh, list_hostkey_types());
2469 
2470 	/* start key exchange */
2471 	if ((r = kex_setup(ssh, myproposal)) != 0)
2472 		fatal_r(r, "kex_setup");
2473 	kex = ssh->kex;
2474 #ifdef WITH_OPENSSL
2475 	kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
2476 	kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
2477 	kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
2478 	kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
2479 	kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
2480 	kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
2481 	kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
2482 # ifdef OPENSSL_HAS_ECC
2483 	kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
2484 # endif
2485 #endif
2486 	kex->kex[KEX_C25519_SHA256] = kex_gen_server;
2487 	kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
2488 	kex->load_host_public_key=&get_hostkey_public_by_type;
2489 	kex->load_host_private_key=&get_hostkey_private_by_type;
2490 	kex->host_key_index=&get_hostkey_index;
2491 	kex->sign = sshd_hostkey_sign;
2492 
2493 	ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &kex->done);
2494 
2495 #ifdef DEBUG_KEXDH
2496 	/* send 1st encrypted/maced/compressed message */
2497 	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2498 	    (r = sshpkt_put_cstring(ssh, "markus")) != 0 ||
2499 	    (r = sshpkt_send(ssh)) != 0 ||
2500 	    (r = ssh_packet_write_wait(ssh)) != 0)
2501 		fatal_fr(r, "send test");
2502 #endif
2503 	debug("KEX done");
2504 }
2505 
2506 /* server specific fatal cleanup */
2507 void
2508 cleanup_exit(int i)
2509 {
2510 	if (the_active_state != NULL && the_authctxt != NULL) {
2511 		do_cleanup(the_active_state, the_authctxt);
2512 		if (use_privsep && privsep_is_preauth &&
2513 		    pmonitor != NULL && pmonitor->m_pid > 1) {
2514 			debug("Killing privsep child %d", pmonitor->m_pid);
2515 			if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
2516 			    errno != ESRCH) {
2517 				error_f("kill(%d): %s", pmonitor->m_pid,
2518 				    strerror(errno));
2519 			}
2520 		}
2521 	}
2522 #ifdef SSH_AUDIT_EVENTS
2523 	/* done after do_cleanup so it can cancel the PAM auth 'thread' */
2524 	if (the_active_state != NULL && (!use_privsep || mm_is_monitor()))
2525 		audit_event(the_active_state, SSH_CONNECTION_ABANDON);
2526 #endif
2527 	_exit(i);
2528 }
2529