xref: /openbsd-src/usr.bin/ssh/ssh.c (revision 3374c67d44f9b75b98444cbf63020f777792342e)
1 /* $OpenBSD: ssh.c,v 1.582 2023/01/06 02:39:59 djm 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  * Ssh client program.  This program can be used to log into a remote machine.
7  * The software supports strong authentication, encryption, and forwarding
8  * of X11, TCP/IP, and authentication connections.
9  *
10  * As far as I am concerned, the code I have written for this software
11  * can be used freely for any purpose.  Any derived versions of this
12  * software must be clearly marked as such, and if the derived work is
13  * incompatible with the protocol description in the RFC file, it must be
14  * called by a name other than "ssh" or "Secure Shell".
15  *
16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
18  *
19  * Modified to work with SSLeay by Niels Provos <provos@citi.umich.edu>
20  * in Canada (German citizen).
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the above copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41  */
42 
43 #include <sys/types.h>
44 #include <sys/ioctl.h>
45 #include <sys/queue.h>
46 #include <sys/resource.h>
47 #include <sys/socket.h>
48 #include <sys/stat.h>
49 #include <sys/time.h>
50 #include <sys/wait.h>
51 
52 #include <ctype.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <netdb.h>
56 #include <paths.h>
57 #include <pwd.h>
58 #include <signal.h>
59 #include <stddef.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <string.h>
63 #include <stdarg.h>
64 #include <unistd.h>
65 #include <limits.h>
66 #include <locale.h>
67 
68 #ifdef WITH_OPENSSL
69 #include <openssl/evp.h>
70 #include <openssl/err.h>
71 #endif
72 
73 #include "xmalloc.h"
74 #include "ssh.h"
75 #include "ssh2.h"
76 #include "canohost.h"
77 #include "compat.h"
78 #include "cipher.h"
79 #include "packet.h"
80 #include "sshbuf.h"
81 #include "channels.h"
82 #include "sshkey.h"
83 #include "authfd.h"
84 #include "authfile.h"
85 #include "pathnames.h"
86 #include "dispatch.h"
87 #include "clientloop.h"
88 #include "log.h"
89 #include "misc.h"
90 #include "readconf.h"
91 #include "sshconnect.h"
92 #include "kex.h"
93 #include "mac.h"
94 #include "sshpty.h"
95 #include "match.h"
96 #include "msg.h"
97 #include "version.h"
98 #include "ssherr.h"
99 #include "myproposal.h"
100 
101 #ifdef ENABLE_PKCS11
102 #include "ssh-pkcs11.h"
103 #endif
104 
105 extern char *__progname;
106 
107 /* Flag indicating whether debug mode is on.  May be set on the command line. */
108 int debug_flag = 0;
109 
110 /* Flag indicating whether a tty should be requested */
111 int tty_flag = 0;
112 
113 /*
114  * Flag indicating that the current process should be backgrounded and
115  * a new mux-client launched in the foreground for ControlPersist.
116  */
117 int need_controlpersist_detach = 0;
118 
119 /* Copies of flags for ControlPersist foreground mux-client */
120 int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
121 
122 /*
123  * General data structure for command line options and options configurable
124  * in configuration files.  See readconf.h.
125  */
126 Options options;
127 
128 /* optional user configfile */
129 char *config = NULL;
130 
131 /*
132  * Name of the host we are connecting to.  This is the name given on the
133  * command line, or the Hostname specified for the user-supplied name in a
134  * configuration file.
135  */
136 char *host;
137 
138 /*
139  * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
140  * not NULL, forward the socket at this path instead.
141  */
142 char *forward_agent_sock_path = NULL;
143 
144 /* socket address the host resolves to */
145 struct sockaddr_storage hostaddr;
146 
147 /* Private host keys. */
148 Sensitive sensitive_data;
149 
150 /* command to be executed */
151 struct sshbuf *command;
152 
153 /* # of replies received for global requests */
154 static int forward_confirms_pending = -1;
155 
156 /* mux.c */
157 extern int muxserver_sock;
158 extern u_int muxclient_command;
159 
160 /* Prints a help message to the user.  This function never returns. */
161 
162 static void
163 usage(void)
164 {
165 	fprintf(stderr,
166 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
167 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
168 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
169 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
170 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
171 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
172 "           [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
173 	);
174 	exit(255);
175 }
176 
177 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
178 static void load_public_identity_files(const struct ssh_conn_info *);
179 static void main_sigchld_handler(int);
180 
181 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
182 static void
183 tilde_expand_paths(char **paths, u_int num_paths)
184 {
185 	u_int i;
186 	char *cp;
187 
188 	for (i = 0; i < num_paths; i++) {
189 		cp = tilde_expand_filename(paths[i], getuid());
190 		free(paths[i]);
191 		paths[i] = cp;
192 	}
193 }
194 
195 /*
196  * Expands the set of percent_expand options used by the majority of keywords
197  * in the client that support percent expansion.
198  * Caller must free returned string.
199  */
200 static char *
201 default_client_percent_expand(const char *str,
202     const struct ssh_conn_info *cinfo)
203 {
204 	return percent_expand(str,
205 	    DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
206 	    (char *)NULL);
207 }
208 
209 /*
210  * Expands the set of percent_expand options used by the majority of keywords
211  * AND perform environment variable substitution.
212  * Caller must free returned string.
213  */
214 static char *
215 default_client_percent_dollar_expand(const char *str,
216     const struct ssh_conn_info *cinfo)
217 {
218 	char *ret;
219 
220 	ret = percent_dollar_expand(str,
221 	    DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
222 	    (char *)NULL);
223 	if (ret == NULL)
224 		fatal("invalid environment variable expansion");
225 	return ret;
226 }
227 
228 /*
229  * Attempt to resolve a host name / port to a set of addresses and
230  * optionally return any CNAMEs encountered along the way.
231  * Returns NULL on failure.
232  * NB. this function must operate with a options having undefined members.
233  */
234 static struct addrinfo *
235 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
236 {
237 	char strport[NI_MAXSERV];
238 	const char *errstr = NULL;
239 	struct addrinfo hints, *res;
240 	int gaierr;
241 	LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
242 
243 	if (port <= 0)
244 		port = default_ssh_port();
245 	if (cname != NULL)
246 		*cname = '\0';
247 	debug3_f("lookup %s:%d", name, port);
248 
249 	snprintf(strport, sizeof strport, "%d", port);
250 	memset(&hints, 0, sizeof(hints));
251 	hints.ai_family = options.address_family == -1 ?
252 	    AF_UNSPEC : options.address_family;
253 	hints.ai_socktype = SOCK_STREAM;
254 	if (cname != NULL)
255 		hints.ai_flags = AI_CANONNAME;
256 	if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
257 		if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
258 			loglevel = SYSLOG_LEVEL_ERROR;
259 		do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
260 		    __progname, name, ssh_gai_strerror(gaierr));
261 		return NULL;
262 	}
263 	if (cname != NULL && res->ai_canonname != NULL) {
264 		if (!valid_domain(res->ai_canonname, 0, &errstr)) {
265 			error("ignoring bad CNAME \"%s\" for host \"%s\": %s",
266 			    res->ai_canonname, name, errstr);
267 		} else if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
268 			error_f("host \"%s\" cname \"%s\" too long (max %lu)",
269 			    name,  res->ai_canonname, (u_long)clen);
270 			if (clen > 0)
271 				*cname = '\0';
272 		}
273 	}
274 	return res;
275 }
276 
277 /* Returns non-zero if name can only be an address and not a hostname */
278 static int
279 is_addr_fast(const char *name)
280 {
281 	return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
282 	    strspn(name, "0123456789.") == strlen(name));
283 }
284 
285 /* Returns non-zero if name represents a valid, single address */
286 static int
287 is_addr(const char *name)
288 {
289 	char strport[NI_MAXSERV];
290 	struct addrinfo hints, *res;
291 
292 	if (is_addr_fast(name))
293 		return 1;
294 
295 	snprintf(strport, sizeof strport, "%u", default_ssh_port());
296 	memset(&hints, 0, sizeof(hints));
297 	hints.ai_family = options.address_family == -1 ?
298 	    AF_UNSPEC : options.address_family;
299 	hints.ai_socktype = SOCK_STREAM;
300 	hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
301 	if (getaddrinfo(name, strport, &hints, &res) != 0)
302 		return 0;
303 	if (res == NULL || res->ai_next != NULL) {
304 		freeaddrinfo(res);
305 		return 0;
306 	}
307 	freeaddrinfo(res);
308 	return 1;
309 }
310 
311 /*
312  * Attempt to resolve a numeric host address / port to a single address.
313  * Returns a canonical address string.
314  * Returns NULL on failure.
315  * NB. this function must operate with a options having undefined members.
316  */
317 static struct addrinfo *
318 resolve_addr(const char *name, int port, char *caddr, size_t clen)
319 {
320 	char addr[NI_MAXHOST], strport[NI_MAXSERV];
321 	struct addrinfo hints, *res;
322 	int gaierr;
323 
324 	if (port <= 0)
325 		port = default_ssh_port();
326 	snprintf(strport, sizeof strport, "%u", port);
327 	memset(&hints, 0, sizeof(hints));
328 	hints.ai_family = options.address_family == -1 ?
329 	    AF_UNSPEC : options.address_family;
330 	hints.ai_socktype = SOCK_STREAM;
331 	hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
332 	if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
333 		debug2_f("could not resolve name %.100s as address: %s",
334 		    name, ssh_gai_strerror(gaierr));
335 		return NULL;
336 	}
337 	if (res == NULL) {
338 		debug_f("getaddrinfo %.100s returned no addresses", name);
339 		return NULL;
340 	}
341 	if (res->ai_next != NULL) {
342 		debug_f("getaddrinfo %.100s returned multiple addresses", name);
343 		goto fail;
344 	}
345 	if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
346 	    addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
347 		debug_f("Could not format address for name %.100s: %s",
348 		    name, ssh_gai_strerror(gaierr));
349 		goto fail;
350 	}
351 	if (strlcpy(caddr, addr, clen) >= clen) {
352 		error_f("host \"%s\" addr \"%s\" too long (max %lu)",
353 		    name,  addr, (u_long)clen);
354 		if (clen > 0)
355 			*caddr = '\0';
356  fail:
357 		freeaddrinfo(res);
358 		return NULL;
359 	}
360 	return res;
361 }
362 
363 /*
364  * Check whether the cname is a permitted replacement for the hostname
365  * and perform the replacement if it is.
366  * NB. this function must operate with a options having undefined members.
367  */
368 static int
369 check_follow_cname(int direct, char **namep, const char *cname)
370 {
371 	int i;
372 	struct allowed_cname *rule;
373 
374 	if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
375 	    strcmp(*namep, cname) == 0)
376 		return 0;
377 	if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
378 		return 0;
379 	/*
380 	 * Don't attempt to canonicalize names that will be interpreted by
381 	 * a proxy or jump host unless the user specifically requests so.
382 	 */
383 	if (!direct &&
384 	    options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
385 		return 0;
386 	debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
387 	for (i = 0; i < options.num_permitted_cnames; i++) {
388 		rule = options.permitted_cnames + i;
389 		if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
390 		    match_pattern_list(cname, rule->target_list, 1) != 1)
391 			continue;
392 		verbose("Canonicalized DNS aliased hostname "
393 		    "\"%s\" => \"%s\"", *namep, cname);
394 		free(*namep);
395 		*namep = xstrdup(cname);
396 		return 1;
397 	}
398 	return 0;
399 }
400 
401 /*
402  * Attempt to resolve the supplied hostname after applying the user's
403  * canonicalization rules. Returns the address list for the host or NULL
404  * if no name was found after canonicalization.
405  * NB. this function must operate with a options having undefined members.
406  */
407 static struct addrinfo *
408 resolve_canonicalize(char **hostp, int port)
409 {
410 	int i, direct, ndots;
411 	char *cp, *fullhost, newname[NI_MAXHOST];
412 	struct addrinfo *addrs;
413 
414 	/*
415 	 * Attempt to canonicalise addresses, regardless of
416 	 * whether hostname canonicalisation was requested
417 	 */
418 	if ((addrs = resolve_addr(*hostp, port,
419 	    newname, sizeof(newname))) != NULL) {
420 		debug2_f("hostname %.100s is address", *hostp);
421 		if (strcasecmp(*hostp, newname) != 0) {
422 			debug2_f("canonicalised address \"%s\" => \"%s\"",
423 			    *hostp, newname);
424 			free(*hostp);
425 			*hostp = xstrdup(newname);
426 		}
427 		return addrs;
428 	}
429 
430 	/*
431 	 * If this looks like an address but didn't parse as one, it might
432 	 * be an address with an invalid interface scope. Skip further
433 	 * attempts at canonicalisation.
434 	 */
435 	if (is_addr_fast(*hostp)) {
436 		debug_f("hostname %.100s is an unrecognised address", *hostp);
437 		return NULL;
438 	}
439 
440 	if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
441 		return NULL;
442 
443 	/*
444 	 * Don't attempt to canonicalize names that will be interpreted by
445 	 * a proxy unless the user specifically requests so.
446 	 */
447 	direct = option_clear_or_none(options.proxy_command) &&
448 	    options.jump_host == NULL;
449 	if (!direct &&
450 	    options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
451 		return NULL;
452 
453 	/* If domain name is anchored, then resolve it now */
454 	if ((*hostp)[strlen(*hostp) - 1] == '.') {
455 		debug3_f("name is fully qualified");
456 		fullhost = xstrdup(*hostp);
457 		if ((addrs = resolve_host(fullhost, port, 0,
458 		    newname, sizeof(newname))) != NULL)
459 			goto found;
460 		free(fullhost);
461 		goto notfound;
462 	}
463 
464 	/* Don't apply canonicalization to sufficiently-qualified hostnames */
465 	ndots = 0;
466 	for (cp = *hostp; *cp != '\0'; cp++) {
467 		if (*cp == '.')
468 			ndots++;
469 	}
470 	if (ndots > options.canonicalize_max_dots) {
471 		debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
472 		    *hostp, options.canonicalize_max_dots);
473 		return NULL;
474 	}
475 	/* Attempt each supplied suffix */
476 	for (i = 0; i < options.num_canonical_domains; i++) {
477 		if (strcasecmp(options.canonical_domains[i], "none") == 0)
478 			break;
479 		xasprintf(&fullhost, "%s.%s.", *hostp,
480 		    options.canonical_domains[i]);
481 		debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
482 		if ((addrs = resolve_host(fullhost, port, 0,
483 		    newname, sizeof(newname))) == NULL) {
484 			free(fullhost);
485 			continue;
486 		}
487  found:
488 		/* Remove trailing '.' */
489 		fullhost[strlen(fullhost) - 1] = '\0';
490 		/* Follow CNAME if requested */
491 		if (!check_follow_cname(direct, &fullhost, newname)) {
492 			debug("Canonicalized hostname \"%s\" => \"%s\"",
493 			    *hostp, fullhost);
494 		}
495 		free(*hostp);
496 		*hostp = fullhost;
497 		return addrs;
498 	}
499  notfound:
500 	if (!options.canonicalize_fallback_local)
501 		fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
502 	debug2_f("host %s not found in any suffix", *hostp);
503 	return NULL;
504 }
505 
506 /*
507  * Check the result of hostkey loading, ignoring some errors and either
508  * discarding the key or fatal()ing for others.
509  */
510 static void
511 check_load(int r, struct sshkey **k, const char *path, const char *message)
512 {
513 	switch (r) {
514 	case 0:
515 		/* Check RSA keys size and discard if undersized */
516 		if (k != NULL && *k != NULL &&
517 		    (r = sshkey_check_rsa_length(*k,
518 		    options.required_rsa_size)) != 0) {
519 			error_r(r, "load %s \"%s\"", message, path);
520 			free(*k);
521 			*k = NULL;
522 		}
523 		break;
524 	case SSH_ERR_INTERNAL_ERROR:
525 	case SSH_ERR_ALLOC_FAIL:
526 		fatal_r(r, "load %s \"%s\"", message, path);
527 	case SSH_ERR_SYSTEM_ERROR:
528 		/* Ignore missing files */
529 		if (errno == ENOENT)
530 			break;
531 		/* FALLTHROUGH */
532 	default:
533 		error_r(r, "load %s \"%s\"", message, path);
534 		break;
535 	}
536 }
537 
538 /*
539  * Read per-user configuration file.  Ignore the system wide config
540  * file if the user specifies a config file on the command line.
541  */
542 static void
543 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
544     int *want_final_pass)
545 {
546 	char buf[PATH_MAX];
547 	int r;
548 
549 	if (config != NULL) {
550 		if (strcasecmp(config, "none") != 0 &&
551 		    !read_config_file(config, pw, host, host_name, &options,
552 		    SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
553 		    want_final_pass))
554 			fatal("Can't open user config file %.100s: "
555 			    "%.100s", config, strerror(errno));
556 	} else {
557 		r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
558 		    _PATH_SSH_USER_CONFFILE);
559 		if (r > 0 && (size_t)r < sizeof(buf))
560 			(void)read_config_file(buf, pw, host, host_name,
561 			    &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
562 			    (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
563 
564 		/* Read systemwide configuration file after user config. */
565 		(void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
566 		    host, host_name, &options,
567 		    final_pass ? SSHCONF_FINAL : 0, want_final_pass);
568 	}
569 }
570 
571 /* Rewrite the port number in an addrinfo list of addresses */
572 static void
573 set_addrinfo_port(struct addrinfo *addrs, int port)
574 {
575 	struct addrinfo *addr;
576 
577 	for (addr = addrs; addr != NULL; addr = addr->ai_next) {
578 		switch (addr->ai_family) {
579 		case AF_INET:
580 			((struct sockaddr_in *)addr->ai_addr)->
581 			    sin_port = htons(port);
582 			break;
583 		case AF_INET6:
584 			((struct sockaddr_in6 *)addr->ai_addr)->
585 			    sin6_port = htons(port);
586 			break;
587 		}
588 	}
589 }
590 
591 static void
592 ssh_conn_info_free(struct ssh_conn_info *cinfo)
593 {
594 	if (cinfo == NULL)
595 		return;
596 	free(cinfo->conn_hash_hex);
597 	free(cinfo->shorthost);
598 	free(cinfo->uidstr);
599 	free(cinfo->keyalias);
600 	free(cinfo->thishost);
601 	free(cinfo->host_arg);
602 	free(cinfo->portstr);
603 	free(cinfo->remhost);
604 	free(cinfo->remuser);
605 	free(cinfo->homedir);
606 	free(cinfo->locuser);
607 	free(cinfo);
608 }
609 
610 /*
611  * Main program for the ssh client.
612  */
613 int
614 main(int ac, char **av)
615 {
616 	struct ssh *ssh = NULL;
617 	int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
618 	int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
619 	char *p, *cp, *line, *argv0, *logfile, *host_arg;
620 	char cname[NI_MAXHOST], thishost[NI_MAXHOST];
621 	struct stat st;
622 	struct passwd *pw;
623 	extern int optind, optreset;
624 	extern char *optarg;
625 	struct Forward fwd;
626 	struct addrinfo *addrs = NULL;
627 	size_t n, len;
628 	u_int j;
629 	struct ssh_conn_info *cinfo = NULL;
630 
631 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
632 	sanitise_stdfd();
633 
634 	/*
635 	 * Discard other fds that are hanging around. These can cause problem
636 	 * with backgrounded ssh processes started by ControlPersist.
637 	 */
638 	closefrom(STDERR_FILENO + 1);
639 
640 	if (getuid() != geteuid())
641 		fatal("ssh setuid not supported.");
642 	if (getgid() != getegid())
643 		fatal("ssh setgid not supported.");
644 
645 	/* Get user data. */
646 	pw = getpwuid(getuid());
647 	if (!pw) {
648 		logit("No user exists for uid %lu", (u_long)getuid());
649 		exit(255);
650 	}
651 	/* Take a copy of the returned structure. */
652 	pw = pwcopy(pw);
653 
654 	/*
655 	 * Set our umask to something reasonable, as some files are created
656 	 * with the default umask.  This will make them world-readable but
657 	 * writable only by the owner, which is ok for all files for which we
658 	 * don't set the modes explicitly.
659 	 */
660 	umask(022 | umask(077));
661 
662 	setlocale(LC_CTYPE, "");
663 
664 	/*
665 	 * Initialize option structure to indicate that no values have been
666 	 * set.
667 	 */
668 	initialize_options(&options);
669 
670 	/*
671 	 * Prepare main ssh transport/connection structures
672 	 */
673 	if ((ssh = ssh_alloc_session_state()) == NULL)
674 		fatal("Couldn't allocate session state");
675 	channel_init_channels(ssh);
676 
677 	/* Parse command-line arguments. */
678 	host = NULL;
679 	use_syslog = 0;
680 	logfile = NULL;
681 	argv0 = av[0];
682 
683  again:
684 	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
685 	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
686 		switch (opt) {
687 		case '1':
688 			fatal("SSH protocol v.1 is no longer supported");
689 			break;
690 		case '2':
691 			/* Ignored */
692 			break;
693 		case '4':
694 			options.address_family = AF_INET;
695 			break;
696 		case '6':
697 			options.address_family = AF_INET6;
698 			break;
699 		case 'n':
700 			options.stdin_null = 1;
701 			break;
702 		case 'f':
703 			options.fork_after_authentication = 1;
704 			options.stdin_null = 1;
705 			break;
706 		case 'x':
707 			options.forward_x11 = 0;
708 			break;
709 		case 'X':
710 			options.forward_x11 = 1;
711 			break;
712 		case 'y':
713 			use_syslog = 1;
714 			break;
715 		case 'E':
716 			logfile = optarg;
717 			break;
718 		case 'G':
719 			config_test = 1;
720 			break;
721 		case 'Y':
722 			options.forward_x11 = 1;
723 			options.forward_x11_trusted = 1;
724 			break;
725 		case 'g':
726 			options.fwd_opts.gateway_ports = 1;
727 			break;
728 		case 'O':
729 			if (options.stdio_forward_host != NULL)
730 				fatal("Cannot specify multiplexing "
731 				    "command with -W");
732 			else if (muxclient_command != 0)
733 				fatal("Multiplexing command already specified");
734 			if (strcmp(optarg, "check") == 0)
735 				muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
736 			else if (strcmp(optarg, "forward") == 0)
737 				muxclient_command = SSHMUX_COMMAND_FORWARD;
738 			else if (strcmp(optarg, "exit") == 0)
739 				muxclient_command = SSHMUX_COMMAND_TERMINATE;
740 			else if (strcmp(optarg, "stop") == 0)
741 				muxclient_command = SSHMUX_COMMAND_STOP;
742 			else if (strcmp(optarg, "cancel") == 0)
743 				muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
744 			else if (strcmp(optarg, "proxy") == 0)
745 				muxclient_command = SSHMUX_COMMAND_PROXY;
746 			else
747 				fatal("Invalid multiplex command.");
748 			break;
749 		case 'P':	/* deprecated */
750 			break;
751 		case 'Q':
752 			cp = NULL;
753 			if (strcmp(optarg, "cipher") == 0 ||
754 			    strcasecmp(optarg, "Ciphers") == 0)
755 				cp = cipher_alg_list('\n', 0);
756 			else if (strcmp(optarg, "cipher-auth") == 0)
757 				cp = cipher_alg_list('\n', 1);
758 			else if (strcmp(optarg, "mac") == 0 ||
759 			    strcasecmp(optarg, "MACs") == 0)
760 				cp = mac_alg_list('\n');
761 			else if (strcmp(optarg, "kex") == 0 ||
762 			    strcasecmp(optarg, "KexAlgorithms") == 0)
763 				cp = kex_alg_list('\n');
764 			else if (strcmp(optarg, "key") == 0)
765 				cp = sshkey_alg_list(0, 0, 0, '\n');
766 			else if (strcmp(optarg, "key-cert") == 0)
767 				cp = sshkey_alg_list(1, 0, 0, '\n');
768 			else if (strcmp(optarg, "key-plain") == 0)
769 				cp = sshkey_alg_list(0, 1, 0, '\n');
770 			else if (strcmp(optarg, "key-sig") == 0 ||
771 			    strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
772 			    strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
773 			    strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
774 			    strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
775 			    strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
776 			    strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
777 				cp = sshkey_alg_list(0, 0, 1, '\n');
778 			else if (strcmp(optarg, "sig") == 0)
779 				cp = sshkey_alg_list(0, 1, 1, '\n');
780 			else if (strcmp(optarg, "protocol-version") == 0)
781 				cp = xstrdup("2");
782 			else if (strcmp(optarg, "compression") == 0) {
783 				cp = xstrdup(compression_alg_list(0));
784 				len = strlen(cp);
785 				for (n = 0; n < len; n++)
786 					if (cp[n] == ',')
787 						cp[n] = '\n';
788 			} else if (strcmp(optarg, "help") == 0) {
789 				cp = xstrdup(
790 				    "cipher\ncipher-auth\ncompression\nkex\n"
791 				    "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
792 				    "protocol-version\nsig");
793 			}
794 			if (cp == NULL)
795 				fatal("Unsupported query \"%s\"", optarg);
796 			printf("%s\n", cp);
797 			free(cp);
798 			exit(0);
799 			break;
800 		case 'a':
801 			options.forward_agent = 0;
802 			break;
803 		case 'A':
804 			options.forward_agent = 1;
805 			break;
806 		case 'k':
807 			options.gss_deleg_creds = 0;
808 			break;
809 		case 'K':
810 			options.gss_authentication = 1;
811 			options.gss_deleg_creds = 1;
812 			break;
813 		case 'i':
814 			p = tilde_expand_filename(optarg, getuid());
815 			if (stat(p, &st) == -1)
816 				fprintf(stderr, "Warning: Identity file %s "
817 				    "not accessible: %s.\n", p,
818 				    strerror(errno));
819 			else
820 				add_identity_file(&options, NULL, p, 1);
821 			free(p);
822 			break;
823 		case 'I':
824 #ifdef ENABLE_PKCS11
825 			free(options.pkcs11_provider);
826 			options.pkcs11_provider = xstrdup(optarg);
827 #else
828 			fprintf(stderr, "no support for PKCS#11.\n");
829 #endif
830 			break;
831 		case 'J':
832 			if (options.jump_host != NULL) {
833 				fatal("Only a single -J option is permitted "
834 				    "(use commas to separate multiple "
835 				    "jump hops)");
836 			}
837 			if (options.proxy_command != NULL)
838 				fatal("Cannot specify -J with ProxyCommand");
839 			if (parse_jump(optarg, &options, 1) == -1)
840 				fatal("Invalid -J argument");
841 			options.proxy_command = xstrdup("none");
842 			break;
843 		case 't':
844 			if (options.request_tty == REQUEST_TTY_YES)
845 				options.request_tty = REQUEST_TTY_FORCE;
846 			else
847 				options.request_tty = REQUEST_TTY_YES;
848 			break;
849 		case 'v':
850 			if (debug_flag == 0) {
851 				debug_flag = 1;
852 				options.log_level = SYSLOG_LEVEL_DEBUG1;
853 			} else {
854 				if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
855 					debug_flag++;
856 					options.log_level++;
857 				}
858 			}
859 			break;
860 		case 'V':
861 			fprintf(stderr, "%s, %s\n",
862 			    SSH_VERSION, SSH_OPENSSL_VERSION);
863 			if (opt == 'V')
864 				exit(0);
865 			break;
866 		case 'w':
867 			if (options.tun_open == -1)
868 				options.tun_open = SSH_TUNMODE_DEFAULT;
869 			options.tun_local = a2tun(optarg, &options.tun_remote);
870 			if (options.tun_local == SSH_TUNID_ERR) {
871 				fprintf(stderr,
872 				    "Bad tun device '%s'\n", optarg);
873 				exit(255);
874 			}
875 			break;
876 		case 'W':
877 			if (options.stdio_forward_host != NULL)
878 				fatal("stdio forward already specified");
879 			if (muxclient_command != 0)
880 				fatal("Cannot specify stdio forward with -O");
881 			if (parse_forward(&fwd, optarg, 1, 0)) {
882 				options.stdio_forward_host = fwd.listen_host;
883 				options.stdio_forward_port = fwd.listen_port;
884 				free(fwd.connect_host);
885 			} else {
886 				fprintf(stderr,
887 				    "Bad stdio forwarding specification '%s'\n",
888 				    optarg);
889 				exit(255);
890 			}
891 			options.request_tty = REQUEST_TTY_NO;
892 			options.session_type = SESSION_TYPE_NONE;
893 			break;
894 		case 'q':
895 			options.log_level = SYSLOG_LEVEL_QUIET;
896 			break;
897 		case 'e':
898 			if (optarg[0] == '^' && optarg[2] == 0 &&
899 			    (u_char) optarg[1] >= 64 &&
900 			    (u_char) optarg[1] < 128)
901 				options.escape_char = (u_char) optarg[1] & 31;
902 			else if (strlen(optarg) == 1)
903 				options.escape_char = (u_char) optarg[0];
904 			else if (strcmp(optarg, "none") == 0)
905 				options.escape_char = SSH_ESCAPECHAR_NONE;
906 			else {
907 				fprintf(stderr, "Bad escape character '%s'.\n",
908 				    optarg);
909 				exit(255);
910 			}
911 			break;
912 		case 'c':
913 			if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
914 			    optarg + 1 : optarg)) {
915 				fprintf(stderr, "Unknown cipher type '%s'\n",
916 				    optarg);
917 				exit(255);
918 			}
919 			free(options.ciphers);
920 			options.ciphers = xstrdup(optarg);
921 			break;
922 		case 'm':
923 			if (mac_valid(optarg)) {
924 				free(options.macs);
925 				options.macs = xstrdup(optarg);
926 			} else {
927 				fprintf(stderr, "Unknown mac type '%s'\n",
928 				    optarg);
929 				exit(255);
930 			}
931 			break;
932 		case 'M':
933 			if (options.control_master == SSHCTL_MASTER_YES)
934 				options.control_master = SSHCTL_MASTER_ASK;
935 			else
936 				options.control_master = SSHCTL_MASTER_YES;
937 			break;
938 		case 'p':
939 			if (options.port == -1) {
940 				options.port = a2port(optarg);
941 				if (options.port <= 0) {
942 					fprintf(stderr, "Bad port '%s'\n",
943 					    optarg);
944 					exit(255);
945 				}
946 			}
947 			break;
948 		case 'l':
949 			if (options.user == NULL)
950 				options.user = optarg;
951 			break;
952 
953 		case 'L':
954 			if (parse_forward(&fwd, optarg, 0, 0))
955 				add_local_forward(&options, &fwd);
956 			else {
957 				fprintf(stderr,
958 				    "Bad local forwarding specification '%s'\n",
959 				    optarg);
960 				exit(255);
961 			}
962 			break;
963 
964 		case 'R':
965 			if (parse_forward(&fwd, optarg, 0, 1) ||
966 			    parse_forward(&fwd, optarg, 1, 1)) {
967 				add_remote_forward(&options, &fwd);
968 			} else {
969 				fprintf(stderr,
970 				    "Bad remote forwarding specification "
971 				    "'%s'\n", optarg);
972 				exit(255);
973 			}
974 			break;
975 
976 		case 'D':
977 			if (parse_forward(&fwd, optarg, 1, 0)) {
978 				add_local_forward(&options, &fwd);
979 			} else {
980 				fprintf(stderr,
981 				    "Bad dynamic forwarding specification "
982 				    "'%s'\n", optarg);
983 				exit(255);
984 			}
985 			break;
986 
987 		case 'C':
988 #ifdef WITH_ZLIB
989 			options.compression = 1;
990 #else
991 			error("Compression not supported, disabling.");
992 #endif
993 			break;
994 		case 'N':
995 			if (options.session_type != -1 &&
996 			    options.session_type != SESSION_TYPE_NONE)
997 				fatal("Cannot specify -N with -s/SessionType");
998 			options.session_type = SESSION_TYPE_NONE;
999 			options.request_tty = REQUEST_TTY_NO;
1000 			break;
1001 		case 'T':
1002 			options.request_tty = REQUEST_TTY_NO;
1003 			break;
1004 		case 'o':
1005 			line = xstrdup(optarg);
1006 			if (process_config_line(&options, pw,
1007 			    host ? host : "", host ? host : "", line,
1008 			    "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1009 				exit(255);
1010 			free(line);
1011 			break;
1012 		case 's':
1013 			if (options.session_type != -1 &&
1014 			    options.session_type != SESSION_TYPE_SUBSYSTEM)
1015 				fatal("Cannot specify -s with -N/SessionType");
1016 			options.session_type = SESSION_TYPE_SUBSYSTEM;
1017 			break;
1018 		case 'S':
1019 			free(options.control_path);
1020 			options.control_path = xstrdup(optarg);
1021 			break;
1022 		case 'b':
1023 			options.bind_address = optarg;
1024 			break;
1025 		case 'B':
1026 			options.bind_interface = optarg;
1027 			break;
1028 		case 'F':
1029 			config = optarg;
1030 			break;
1031 		default:
1032 			usage();
1033 		}
1034 	}
1035 
1036 	if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1037 		opt_terminated = 1;
1038 
1039 	ac -= optind;
1040 	av += optind;
1041 
1042 	if (ac > 0 && !host) {
1043 		int tport;
1044 		char *tuser;
1045 		switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1046 		case -1:
1047 			usage();
1048 			break;
1049 		case 0:
1050 			if (options.user == NULL) {
1051 				options.user = tuser;
1052 				tuser = NULL;
1053 			}
1054 			free(tuser);
1055 			if (options.port == -1 && tport != -1)
1056 				options.port = tport;
1057 			break;
1058 		default:
1059 			p = xstrdup(*av);
1060 			cp = strrchr(p, '@');
1061 			if (cp != NULL) {
1062 				if (cp == p)
1063 					usage();
1064 				if (options.user == NULL) {
1065 					options.user = p;
1066 					p = NULL;
1067 				}
1068 				*cp++ = '\0';
1069 				host = xstrdup(cp);
1070 				free(p);
1071 			} else
1072 				host = p;
1073 			break;
1074 		}
1075 		if (ac > 1 && !opt_terminated) {
1076 			optind = optreset = 1;
1077 			goto again;
1078 		}
1079 		ac--, av++;
1080 	}
1081 
1082 	/* Check that we got a host name. */
1083 	if (!host)
1084 		usage();
1085 
1086 	host_arg = xstrdup(host);
1087 
1088 #ifdef WITH_OPENSSL
1089 	OpenSSL_add_all_algorithms();
1090 	ERR_load_crypto_strings();
1091 #endif
1092 
1093 	/* Initialize the command to execute on remote host. */
1094 	if ((command = sshbuf_new()) == NULL)
1095 		fatal("sshbuf_new failed");
1096 
1097 	/*
1098 	 * Save the command to execute on the remote host in a buffer. There
1099 	 * is no limit on the length of the command, except by the maximum
1100 	 * packet size.  Also sets the tty flag if there is no command.
1101 	 */
1102 	if (!ac) {
1103 		/* No command specified - execute shell on a tty. */
1104 		if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1105 			fprintf(stderr,
1106 			    "You must specify a subsystem to invoke.\n");
1107 			usage();
1108 		}
1109 	} else {
1110 		/* A command has been specified.  Store it into the buffer. */
1111 		for (i = 0; i < ac; i++) {
1112 			if ((r = sshbuf_putf(command, "%s%s",
1113 			    i ? " " : "", av[i])) != 0)
1114 				fatal_fr(r, "buffer error");
1115 		}
1116 	}
1117 
1118 	ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1119 
1120 	/*
1121 	 * Initialize "log" output.  Since we are the client all output
1122 	 * goes to stderr unless otherwise specified by -y or -E.
1123 	 */
1124 	if (use_syslog && logfile != NULL)
1125 		fatal("Can't specify both -y and -E");
1126 	if (logfile != NULL)
1127 		log_redirect_stderr_to(logfile);
1128 	log_init(argv0,
1129 	    options.log_level == SYSLOG_LEVEL_NOT_SET ?
1130 	    SYSLOG_LEVEL_INFO : options.log_level,
1131 	    options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1132 	    SYSLOG_FACILITY_USER : options.log_facility,
1133 	    !use_syslog);
1134 
1135 	if (debug_flag)
1136 		logit("%s, %s", SSH_VERSION, SSH_OPENSSL_VERSION);
1137 
1138 	/* Parse the configuration files */
1139 	process_config_files(host_arg, pw, 0, &want_final_pass);
1140 	if (want_final_pass)
1141 		debug("configuration requests final Match pass");
1142 
1143 	/* Hostname canonicalisation needs a few options filled. */
1144 	fill_default_options_for_canonicalization(&options);
1145 
1146 	/* If the user has replaced the hostname then take it into use now */
1147 	if (options.hostname != NULL) {
1148 		/* NB. Please keep in sync with readconf.c:match_cfg_line() */
1149 		cp = percent_expand(options.hostname,
1150 		    "h", host, (char *)NULL);
1151 		free(host);
1152 		host = cp;
1153 		free(options.hostname);
1154 		options.hostname = xstrdup(host);
1155 	}
1156 
1157 	/* Don't lowercase addresses, they will be explicitly canonicalised */
1158 	if ((was_addr = is_addr(host)) == 0)
1159 		lowercase(host);
1160 
1161 	/*
1162 	 * Try to canonicalize if requested by configuration or the
1163 	 * hostname is an address.
1164 	 */
1165 	if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1166 		addrs = resolve_canonicalize(&host, options.port);
1167 
1168 	/*
1169 	 * If CanonicalizePermittedCNAMEs have been specified but
1170 	 * other canonicalization did not happen (by not being requested
1171 	 * or by failing with fallback) then the hostname may still be changed
1172 	 * as a result of CNAME following.
1173 	 *
1174 	 * Try to resolve the bare hostname name using the system resolver's
1175 	 * usual search rules and then apply the CNAME follow rules.
1176 	 *
1177 	 * Skip the lookup if a ProxyCommand is being used unless the user
1178 	 * has specifically requested canonicalisation for this case via
1179 	 * CanonicalizeHostname=always
1180 	 */
1181 	direct = option_clear_or_none(options.proxy_command) &&
1182 	    options.jump_host == NULL;
1183 	if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1184 	    options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1185 		if ((addrs = resolve_host(host, options.port,
1186 		    direct, cname, sizeof(cname))) == NULL) {
1187 			/* Don't fatal proxied host names not in the DNS */
1188 			if (direct)
1189 				cleanup_exit(255); /* logged in resolve_host */
1190 		} else
1191 			check_follow_cname(direct, &host, cname);
1192 	}
1193 
1194 	/*
1195 	 * If canonicalisation is enabled then re-parse the configuration
1196 	 * files as new stanzas may match.
1197 	 */
1198 	if (options.canonicalize_hostname != 0 && !want_final_pass) {
1199 		debug("hostname canonicalisation enabled, "
1200 		    "will re-parse configuration");
1201 		want_final_pass = 1;
1202 	}
1203 
1204 	if (want_final_pass) {
1205 		debug("re-parsing configuration");
1206 		free(options.hostname);
1207 		options.hostname = xstrdup(host);
1208 		process_config_files(host_arg, pw, 1, NULL);
1209 		/*
1210 		 * Address resolution happens early with canonicalisation
1211 		 * enabled and the port number may have changed since, so
1212 		 * reset it in address list
1213 		 */
1214 		if (addrs != NULL && options.port > 0)
1215 			set_addrinfo_port(addrs, options.port);
1216 	}
1217 
1218 	/* Fill configuration defaults. */
1219 	if (fill_default_options(&options) != 0)
1220 		cleanup_exit(255);
1221 
1222 	if (options.user == NULL)
1223 		options.user = xstrdup(pw->pw_name);
1224 
1225 	/*
1226 	 * If ProxyJump option specified, then construct a ProxyCommand now.
1227 	 */
1228 	if (options.jump_host != NULL) {
1229 		char port_s[8];
1230 		const char *jumpuser = options.jump_user, *sshbin = argv0;
1231 		int port = options.port, jumpport = options.jump_port;
1232 
1233 		if (port <= 0)
1234 			port = default_ssh_port();
1235 		if (jumpport <= 0)
1236 			jumpport = default_ssh_port();
1237 		if (jumpuser == NULL)
1238 			jumpuser = options.user;
1239 		if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1240 		    strcmp(options.user, jumpuser) == 0)
1241 			fatal("jumphost loop via %s", options.jump_host);
1242 
1243 		/*
1244 		 * Try to use SSH indicated by argv[0], but fall back to
1245 		 * "ssh" if it appears unavailable.
1246 		 */
1247 		if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1248 			sshbin = "ssh";
1249 
1250 		/* Consistency check */
1251 		if (options.proxy_command != NULL)
1252 			fatal("inconsistent options: ProxyCommand+ProxyJump");
1253 		/* Never use FD passing for ProxyJump */
1254 		options.proxy_use_fdpass = 0;
1255 		snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1256 		xasprintf(&options.proxy_command,
1257 		    "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1258 		    sshbin,
1259 		    /* Optional "-l user" argument if jump_user set */
1260 		    options.jump_user == NULL ? "" : " -l ",
1261 		    options.jump_user == NULL ? "" : options.jump_user,
1262 		    /* Optional "-p port" argument if jump_port set */
1263 		    options.jump_port <= 0 ? "" : " -p ",
1264 		    options.jump_port <= 0 ? "" : port_s,
1265 		    /* Optional additional jump hosts ",..." */
1266 		    options.jump_extra == NULL ? "" : " -J ",
1267 		    options.jump_extra == NULL ? "" : options.jump_extra,
1268 		    /* Optional "-F" argument if -F specified */
1269 		    config == NULL ? "" : " -F ",
1270 		    config == NULL ? "" : config,
1271 		    /* Optional "-v" arguments if -v set */
1272 		    debug_flag ? " -" : "",
1273 		    debug_flag, "vvv",
1274 		    /* Mandatory hostname */
1275 		    options.jump_host);
1276 		debug("Setting implicit ProxyCommand from ProxyJump: %s",
1277 		    options.proxy_command);
1278 	}
1279 
1280 	if (options.port == 0)
1281 		options.port = default_ssh_port();
1282 	channel_set_af(ssh, options.address_family);
1283 
1284 	/* Tidy and check options */
1285 	if (options.host_key_alias != NULL)
1286 		lowercase(options.host_key_alias);
1287 	if (options.proxy_command != NULL &&
1288 	    strcmp(options.proxy_command, "-") == 0 &&
1289 	    options.proxy_use_fdpass)
1290 		fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1291 	if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1292 		if (options.control_persist && options.control_path != NULL) {
1293 			debug("UpdateHostKeys=ask is incompatible with "
1294 			    "ControlPersist; disabling");
1295 			options.update_hostkeys = 0;
1296 		} else if (sshbuf_len(command) != 0 ||
1297 		    options.remote_command != NULL ||
1298 		    options.request_tty == REQUEST_TTY_NO) {
1299 			debug("UpdateHostKeys=ask is incompatible with "
1300 			    "remote command execution; disabling");
1301 			options.update_hostkeys = 0;
1302 		} else if (options.log_level < SYSLOG_LEVEL_INFO) {
1303 			/* no point logging anything; user won't see it */
1304 			options.update_hostkeys = 0;
1305 		}
1306 	}
1307 	if (options.connection_attempts <= 0)
1308 		fatal("Invalid number of ConnectionAttempts");
1309 
1310 	if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1311 		fatal("Cannot execute command-line and remote command.");
1312 
1313 	/* Cannot fork to background if no command. */
1314 	if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1315 	    options.remote_command == NULL &&
1316 	    options.session_type != SESSION_TYPE_NONE)
1317 		fatal("Cannot fork into background without a command "
1318 		    "to execute.");
1319 
1320 	/* reinit */
1321 	log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1322 	for (j = 0; j < options.num_log_verbose; j++) {
1323 		if (strcasecmp(options.log_verbose[j], "none") == 0)
1324 			break;
1325 		log_verbose_add(options.log_verbose[j]);
1326 	}
1327 
1328 	if (options.request_tty == REQUEST_TTY_YES ||
1329 	    options.request_tty == REQUEST_TTY_FORCE)
1330 		tty_flag = 1;
1331 
1332 	/* Allocate a tty by default if no command specified. */
1333 	if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1334 		tty_flag = options.request_tty != REQUEST_TTY_NO;
1335 
1336 	/* Force no tty */
1337 	if (options.request_tty == REQUEST_TTY_NO ||
1338 	    (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY) ||
1339 	    options.session_type == SESSION_TYPE_NONE)
1340 		tty_flag = 0;
1341 	/* Do not allocate a tty if stdin is not a tty. */
1342 	if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1343 	    options.request_tty != REQUEST_TTY_FORCE) {
1344 		if (tty_flag)
1345 			logit("Pseudo-terminal will not be allocated because "
1346 			    "stdin is not a terminal.");
1347 		tty_flag = 0;
1348 	}
1349 
1350 	/* Set up strings used to percent_expand() arguments */
1351 	cinfo = xcalloc(1, sizeof(*cinfo));
1352 	if (gethostname(thishost, sizeof(thishost)) == -1)
1353 		fatal("gethostname: %s", strerror(errno));
1354 	cinfo->thishost = xstrdup(thishost);
1355 	thishost[strcspn(thishost, ".")] = '\0';
1356 	cinfo->shorthost = xstrdup(thishost);
1357 	xasprintf(&cinfo->portstr, "%d", options.port);
1358 	xasprintf(&cinfo->uidstr, "%llu",
1359 	    (unsigned long long)pw->pw_uid);
1360 	cinfo->keyalias = xstrdup(options.host_key_alias ?
1361 	    options.host_key_alias : host_arg);
1362 	cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1363 	    cinfo->portstr, options.user);
1364 	cinfo->host_arg = xstrdup(host_arg);
1365 	cinfo->remhost = xstrdup(host);
1366 	cinfo->remuser = xstrdup(options.user);
1367 	cinfo->homedir = xstrdup(pw->pw_dir);
1368 	cinfo->locuser = xstrdup(pw->pw_name);
1369 
1370 	/*
1371 	 * Expand tokens in arguments. NB. LocalCommand is expanded later,
1372 	 * after port-forwarding is set up, so it may pick up any local
1373 	 * tunnel interface name allocated.
1374 	 */
1375 	if (options.remote_command != NULL) {
1376 		debug3("expanding RemoteCommand: %s", options.remote_command);
1377 		cp = options.remote_command;
1378 		options.remote_command = default_client_percent_expand(cp,
1379 		    cinfo);
1380 		debug3("expanded RemoteCommand: %s", options.remote_command);
1381 		free(cp);
1382 		if ((r = sshbuf_put(command, options.remote_command,
1383 		    strlen(options.remote_command))) != 0)
1384 			fatal_fr(r, "buffer error");
1385 	}
1386 
1387 	if (options.control_path != NULL) {
1388 		cp = tilde_expand_filename(options.control_path, getuid());
1389 		free(options.control_path);
1390 		options.control_path = default_client_percent_dollar_expand(cp,
1391 		    cinfo);
1392 		free(cp);
1393 	}
1394 
1395 	if (options.identity_agent != NULL) {
1396 		p = tilde_expand_filename(options.identity_agent, getuid());
1397 		cp = default_client_percent_dollar_expand(p, cinfo);
1398 		free(p);
1399 		free(options.identity_agent);
1400 		options.identity_agent = cp;
1401 	}
1402 
1403 	if (options.forward_agent_sock_path != NULL) {
1404 		p = tilde_expand_filename(options.forward_agent_sock_path,
1405 		    getuid());
1406 		cp = default_client_percent_dollar_expand(p, cinfo);
1407 		free(p);
1408 		free(options.forward_agent_sock_path);
1409 		options.forward_agent_sock_path = cp;
1410 		if (stat(options.forward_agent_sock_path, &st) != 0) {
1411 			error("Cannot forward agent socket path \"%s\": %s",
1412 			    options.forward_agent_sock_path, strerror(errno));
1413 			if (options.exit_on_forward_failure)
1414 				cleanup_exit(255);
1415 		}
1416 	}
1417 
1418 	if (options.num_system_hostfiles > 0 &&
1419 	    strcasecmp(options.system_hostfiles[0], "none") == 0) {
1420 		if (options.num_system_hostfiles > 1)
1421 			fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1422 			    "appears with other entries");
1423 		free(options.system_hostfiles[0]);
1424 		options.system_hostfiles[0] = NULL;
1425 		options.num_system_hostfiles = 0;
1426 	}
1427 
1428 	if (options.num_user_hostfiles > 0 &&
1429 	    strcasecmp(options.user_hostfiles[0], "none") == 0) {
1430 		if (options.num_user_hostfiles > 1)
1431 			fatal("Invalid UserKnownHostsFiles: \"none\" "
1432 			    "appears with other entries");
1433 		free(options.user_hostfiles[0]);
1434 		options.user_hostfiles[0] = NULL;
1435 		options.num_user_hostfiles = 0;
1436 	}
1437 	for (j = 0; j < options.num_user_hostfiles; j++) {
1438 		if (options.user_hostfiles[j] == NULL)
1439 			continue;
1440 		cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1441 		p = default_client_percent_dollar_expand(cp, cinfo);
1442 		if (strcmp(options.user_hostfiles[j], p) != 0)
1443 			debug3("expanded UserKnownHostsFile '%s' -> "
1444 			    "'%s'", options.user_hostfiles[j], p);
1445 		free(options.user_hostfiles[j]);
1446 		free(cp);
1447 		options.user_hostfiles[j] = p;
1448 	}
1449 
1450 	for (i = 0; i < options.num_local_forwards; i++) {
1451 		if (options.local_forwards[i].listen_path != NULL) {
1452 			cp = options.local_forwards[i].listen_path;
1453 			p = options.local_forwards[i].listen_path =
1454 			    default_client_percent_expand(cp, cinfo);
1455 			if (strcmp(cp, p) != 0)
1456 				debug3("expanded LocalForward listen path "
1457 				    "'%s' -> '%s'", cp, p);
1458 			free(cp);
1459 		}
1460 		if (options.local_forwards[i].connect_path != NULL) {
1461 			cp = options.local_forwards[i].connect_path;
1462 			p = options.local_forwards[i].connect_path =
1463 			    default_client_percent_expand(cp, cinfo);
1464 			if (strcmp(cp, p) != 0)
1465 				debug3("expanded LocalForward connect path "
1466 				    "'%s' -> '%s'", cp, p);
1467 			free(cp);
1468 		}
1469 	}
1470 
1471 	for (i = 0; i < options.num_remote_forwards; i++) {
1472 		if (options.remote_forwards[i].listen_path != NULL) {
1473 			cp = options.remote_forwards[i].listen_path;
1474 			p = options.remote_forwards[i].listen_path =
1475 			    default_client_percent_expand(cp, cinfo);
1476 			if (strcmp(cp, p) != 0)
1477 				debug3("expanded RemoteForward listen path "
1478 				    "'%s' -> '%s'", cp, p);
1479 			free(cp);
1480 		}
1481 		if (options.remote_forwards[i].connect_path != NULL) {
1482 			cp = options.remote_forwards[i].connect_path;
1483 			p = options.remote_forwards[i].connect_path =
1484 			    default_client_percent_expand(cp, cinfo);
1485 			if (strcmp(cp, p) != 0)
1486 				debug3("expanded RemoteForward connect path "
1487 				    "'%s' -> '%s'", cp, p);
1488 			free(cp);
1489 		}
1490 	}
1491 
1492 	if (config_test) {
1493 		dump_client_config(&options, host);
1494 		exit(0);
1495 	}
1496 
1497 	/* Expand SecurityKeyProvider if it refers to an environment variable */
1498 	if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1499 	    strlen(options.sk_provider) > 1) {
1500 		if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1501 			debug("Authenticator provider %s did not resolve; "
1502 			    "disabling", options.sk_provider);
1503 			free(options.sk_provider);
1504 			options.sk_provider = NULL;
1505 		} else {
1506 			debug2("resolved SecurityKeyProvider %s => %s",
1507 			    options.sk_provider, cp);
1508 			free(options.sk_provider);
1509 			options.sk_provider = xstrdup(cp);
1510 		}
1511 	}
1512 
1513 	if (muxclient_command != 0 && options.control_path == NULL)
1514 		fatal("No ControlPath specified for \"-O\" command");
1515 	if (options.control_path != NULL) {
1516 		int sock;
1517 		if ((sock = muxclient(options.control_path)) >= 0) {
1518 			ssh_packet_set_connection(ssh, sock, sock);
1519 			ssh_packet_set_mux(ssh);
1520 			goto skip_connect;
1521 		}
1522 	}
1523 
1524 	/*
1525 	 * If hostname canonicalisation was not enabled, then we may not
1526 	 * have yet resolved the hostname. Do so now.
1527 	 */
1528 	if (addrs == NULL && options.proxy_command == NULL) {
1529 		debug2("resolving \"%s\" port %d", host, options.port);
1530 		if ((addrs = resolve_host(host, options.port, 1,
1531 		    cname, sizeof(cname))) == NULL)
1532 			cleanup_exit(255); /* resolve_host logs the error */
1533 	}
1534 
1535 	if (options.connection_timeout >= INT_MAX/1000)
1536 		timeout_ms = INT_MAX;
1537 	else
1538 		timeout_ms = options.connection_timeout * 1000;
1539 
1540 	/* Open a connection to the remote host. */
1541 	if (ssh_connect(ssh, host, host_arg, addrs, &hostaddr, options.port,
1542 	    options.connection_attempts,
1543 	    &timeout_ms, options.tcp_keep_alive) != 0)
1544 		exit(255);
1545 
1546 	if (addrs != NULL)
1547 		freeaddrinfo(addrs);
1548 
1549 	ssh_packet_set_timeout(ssh, options.server_alive_interval,
1550 	    options.server_alive_count_max);
1551 
1552 	if (timeout_ms > 0)
1553 		debug3("timeout: %d ms remain after connect", timeout_ms);
1554 
1555 	/*
1556 	 * If we successfully made the connection and we have hostbased auth
1557 	 * enabled, load the public keys so we can later use the ssh-keysign
1558 	 * helper to sign challenges.
1559 	 */
1560 	sensitive_data.nkeys = 0;
1561 	sensitive_data.keys = NULL;
1562 	if (options.hostbased_authentication) {
1563 		int loaded = 0;
1564 
1565 		sensitive_data.nkeys = 10;
1566 		sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1567 		    sizeof(*sensitive_data.keys));
1568 
1569 		/* XXX check errors? */
1570 #define L_PUBKEY(p,o) do { \
1571 	if ((o) >= sensitive_data.nkeys) \
1572 		fatal_f("pubkey out of array bounds"); \
1573 	check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1574 	    &(sensitive_data.keys[o]), p, "pubkey"); \
1575 	if (sensitive_data.keys[o] != NULL) { \
1576 		debug2("hostbased key %d: %s key from \"%s\"", o, \
1577 		    sshkey_ssh_name(sensitive_data.keys[o]), p); \
1578 		loaded++; \
1579 	} \
1580 } while (0)
1581 #define L_CERT(p,o) do { \
1582 	if ((o) >= sensitive_data.nkeys) \
1583 		fatal_f("cert out of array bounds"); \
1584 	check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), \
1585 	    &(sensitive_data.keys[o]), p, "cert"); \
1586 	if (sensitive_data.keys[o] != NULL) { \
1587 		debug2("hostbased key %d: %s cert from \"%s\"", o, \
1588 		    sshkey_ssh_name(sensitive_data.keys[o]), p); \
1589 		loaded++; \
1590 	} \
1591 } while (0)
1592 
1593 		if (options.hostbased_authentication == 1) {
1594 			L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1595 			L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1596 			L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1597 			L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1598 			L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1599 			L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1600 			L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1601 			L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1602 			L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1603 			L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1604 			if (loaded == 0)
1605 				debug("HostbasedAuthentication enabled but no "
1606 				   "local public host keys could be loaded.");
1607 		}
1608 	}
1609 
1610 	/* load options.identity_files */
1611 	load_public_identity_files(cinfo);
1612 
1613 	/* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1614 	if (options.identity_agent &&
1615 	    strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1616 		if (strcmp(options.identity_agent, "none") == 0) {
1617 			unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1618 		} else {
1619 			cp = options.identity_agent;
1620 			/* legacy (limited) format */
1621 			if (cp[0] == '$' && cp[1] != '{') {
1622 				if (!valid_env_name(cp + 1)) {
1623 					fatal("Invalid IdentityAgent "
1624 					    "environment variable name %s", cp);
1625 				}
1626 				if ((p = getenv(cp + 1)) == NULL)
1627 					unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1628 				else
1629 					setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1630 			} else {
1631 				/* identity_agent specifies a path directly */
1632 				setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1633 			}
1634 		}
1635 	}
1636 
1637 	if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1638 		cp = options.forward_agent_sock_path;
1639 		if (cp[0] == '$') {
1640 			if (!valid_env_name(cp + 1)) {
1641 				fatal("Invalid ForwardAgent environment variable name %s", cp);
1642 			}
1643 			if ((p = getenv(cp + 1)) != NULL)
1644 				forward_agent_sock_path = xstrdup(p);
1645 			else
1646 				options.forward_agent = 0;
1647 			free(cp);
1648 		} else {
1649 			forward_agent_sock_path = cp;
1650 		}
1651 	}
1652 
1653 	/* Expand ~ in known host file names. */
1654 	tilde_expand_paths(options.system_hostfiles,
1655 	    options.num_system_hostfiles);
1656 	tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1657 
1658 	ssh_signal(SIGCHLD, main_sigchld_handler);
1659 
1660 	/* Log into the remote system.  Never returns if the login fails. */
1661 	ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1662 	    options.port, pw, timeout_ms, cinfo);
1663 
1664 	/* We no longer need the private host keys.  Clear them now. */
1665 	if (sensitive_data.nkeys != 0) {
1666 		for (i = 0; i < sensitive_data.nkeys; i++) {
1667 			if (sensitive_data.keys[i] != NULL) {
1668 				/* Destroys contents safely */
1669 				debug3("clear hostkey %d", i);
1670 				sshkey_free(sensitive_data.keys[i]);
1671 				sensitive_data.keys[i] = NULL;
1672 			}
1673 		}
1674 		free(sensitive_data.keys);
1675 	}
1676 	for (i = 0; i < options.num_identity_files; i++) {
1677 		free(options.identity_files[i]);
1678 		options.identity_files[i] = NULL;
1679 		if (options.identity_keys[i]) {
1680 			sshkey_free(options.identity_keys[i]);
1681 			options.identity_keys[i] = NULL;
1682 		}
1683 	}
1684 	for (i = 0; i < options.num_certificate_files; i++) {
1685 		free(options.certificate_files[i]);
1686 		options.certificate_files[i] = NULL;
1687 	}
1688 
1689 #ifdef ENABLE_PKCS11
1690 	(void)pkcs11_del_provider(options.pkcs11_provider);
1691 #endif
1692 
1693  skip_connect:
1694 	exit_status = ssh_session2(ssh, cinfo);
1695 	ssh_conn_info_free(cinfo);
1696 	ssh_packet_close(ssh);
1697 
1698 	if (options.control_path != NULL && muxserver_sock != -1)
1699 		unlink(options.control_path);
1700 
1701 	/* Kill ProxyCommand if it is running. */
1702 	ssh_kill_proxy_command();
1703 
1704 	return exit_status;
1705 }
1706 
1707 static void
1708 control_persist_detach(void)
1709 {
1710 	pid_t pid;
1711 
1712 	debug_f("backgrounding master process");
1713 
1714 	/*
1715 	 * master (current process) into the background, and make the
1716 	 * foreground process a client of the backgrounded master.
1717 	 */
1718 	switch ((pid = fork())) {
1719 	case -1:
1720 		fatal_f("fork: %s", strerror(errno));
1721 	case 0:
1722 		/* Child: master process continues mainloop */
1723 		break;
1724 	default:
1725 		/* Parent: set up mux client to connect to backgrounded master */
1726 		debug2_f("background process is %ld", (long)pid);
1727 		options.stdin_null = ostdin_null_flag;
1728 		options.request_tty = orequest_tty;
1729 		tty_flag = otty_flag;
1730 		options.session_type = osession_type;
1731 		close(muxserver_sock);
1732 		muxserver_sock = -1;
1733 		options.control_master = SSHCTL_MASTER_NO;
1734 		muxclient(options.control_path);
1735 		/* muxclient() doesn't return on success. */
1736 		fatal("Failed to connect to new control master");
1737 	}
1738 	if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1739 		error_f("stdfd_devnull failed");
1740 	daemon(1, 1);
1741 	setproctitle("%s [mux]", options.control_path);
1742 }
1743 
1744 /* Do fork() after authentication. Used by "ssh -f" */
1745 static void
1746 fork_postauth(void)
1747 {
1748 	if (need_controlpersist_detach)
1749 		control_persist_detach();
1750 	debug("forking to background");
1751 	options.fork_after_authentication = 0;
1752 	if (daemon(1, 1) == -1)
1753 		fatal("daemon() failed: %.200s", strerror(errno));
1754 	if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1755 		error_f("stdfd_devnull failed");
1756 }
1757 
1758 static void
1759 forwarding_success(void)
1760 {
1761 	if (forward_confirms_pending == -1)
1762 		return;
1763 	if (--forward_confirms_pending == 0) {
1764 		debug_f("all expected forwarding replies received");
1765 		if (options.fork_after_authentication)
1766 			fork_postauth();
1767 	} else {
1768 		debug2_f("%d expected forwarding replies remaining",
1769 		    forward_confirms_pending);
1770 	}
1771 }
1772 
1773 /* Callback for remote forward global requests */
1774 static void
1775 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1776 {
1777 	struct Forward *rfwd = (struct Forward *)ctxt;
1778 	u_int port;
1779 	int r;
1780 
1781 	/* XXX verbose() on failure? */
1782 	debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1783 	    type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1784 	    rfwd->listen_path ? rfwd->listen_path :
1785 	    rfwd->listen_host ? rfwd->listen_host : "",
1786 	    (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1787 	    rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1788 	    rfwd->connect_host, rfwd->connect_port);
1789 	if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1790 		if (type == SSH2_MSG_REQUEST_SUCCESS) {
1791 			if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1792 				fatal_fr(r, "parse packet");
1793 			if (port > 65535) {
1794 				error("Invalid allocated port %u for remote "
1795 				    "forward to %s:%d", port,
1796 				    rfwd->connect_host, rfwd->connect_port);
1797 				/* Ensure failure processing runs below */
1798 				type = SSH2_MSG_REQUEST_FAILURE;
1799 				channel_update_permission(ssh,
1800 				    rfwd->handle, -1);
1801 			} else {
1802 				rfwd->allocated_port = (int)port;
1803 				logit("Allocated port %u for remote "
1804 				    "forward to %s:%d",
1805 				    rfwd->allocated_port, rfwd->connect_path ?
1806 				    rfwd->connect_path : rfwd->connect_host,
1807 				    rfwd->connect_port);
1808 				channel_update_permission(ssh,
1809 				    rfwd->handle, rfwd->allocated_port);
1810 			}
1811 		} else {
1812 			channel_update_permission(ssh, rfwd->handle, -1);
1813 		}
1814 	}
1815 
1816 	if (type == SSH2_MSG_REQUEST_FAILURE) {
1817 		if (options.exit_on_forward_failure) {
1818 			if (rfwd->listen_path != NULL)
1819 				fatal("Error: remote port forwarding failed "
1820 				    "for listen path %s", rfwd->listen_path);
1821 			else
1822 				fatal("Error: remote port forwarding failed "
1823 				    "for listen port %d", rfwd->listen_port);
1824 		} else {
1825 			if (rfwd->listen_path != NULL)
1826 				logit("Warning: remote port forwarding failed "
1827 				    "for listen path %s", rfwd->listen_path);
1828 			else
1829 				logit("Warning: remote port forwarding failed "
1830 				    "for listen port %d", rfwd->listen_port);
1831 		}
1832 	}
1833 	forwarding_success();
1834 }
1835 
1836 static void
1837 client_cleanup_stdio_fwd(struct ssh *ssh, int id, int force, void *arg)
1838 {
1839 	debug("stdio forwarding: done");
1840 	cleanup_exit(0);
1841 }
1842 
1843 static void
1844 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1845 {
1846 	if (!success)
1847 		fatal("stdio forwarding failed");
1848 }
1849 
1850 static void
1851 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1852 {
1853 	if (!success) {
1854 		error("Tunnel forwarding failed");
1855 		if (options.exit_on_forward_failure)
1856 			cleanup_exit(255);
1857 	}
1858 
1859 	debug_f("tunnel forward established, id=%d", id);
1860 	forwarding_success();
1861 }
1862 
1863 static void
1864 ssh_init_stdio_forwarding(struct ssh *ssh)
1865 {
1866 	Channel *c;
1867 	int in, out;
1868 
1869 	if (options.stdio_forward_host == NULL)
1870 		return;
1871 
1872 	debug3_f("%s:%d", options.stdio_forward_host,
1873 	    options.stdio_forward_port);
1874 
1875 	if ((in = dup(STDIN_FILENO)) == -1 ||
1876 	    (out = dup(STDOUT_FILENO)) == -1)
1877 		fatal_f("dup() in/out failed");
1878 	if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1879 	    options.stdio_forward_port, in, out,
1880 	    CHANNEL_NONBLOCK_STDIO)) == NULL)
1881 		fatal_f("channel_connect_stdio_fwd failed");
1882 	channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1883 	channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1884 }
1885 
1886 static void
1887 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1888     u_int num_opens)
1889 {
1890 	u_int i;
1891 	int port;
1892 	char *addr, *arg, *oarg;
1893 	int where = FORWARD_LOCAL;
1894 
1895 	channel_clear_permission(ssh, FORWARD_ADM, where);
1896 	if (num_opens == 0)
1897 		return; /* permit any */
1898 
1899 	/* handle keywords: "any" / "none" */
1900 	if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1901 		return;
1902 	if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1903 		channel_disable_admin(ssh, where);
1904 		return;
1905 	}
1906 	/* Otherwise treat it as a list of permitted host:port */
1907 	for (i = 0; i < num_opens; i++) {
1908 		oarg = arg = xstrdup(opens[i]);
1909 		addr = hpdelim(&arg);
1910 		if (addr == NULL)
1911 			fatal_f("missing host in %s", what);
1912 		addr = cleanhostname(addr);
1913 		if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1914 			fatal_f("bad port number in %s", what);
1915 		/* Send it to channels layer */
1916 		channel_add_permission(ssh, FORWARD_ADM,
1917 		    where, addr, port);
1918 		free(oarg);
1919 	}
1920 }
1921 
1922 static void
1923 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1924 {
1925 	int success = 0;
1926 	int i;
1927 
1928 	ssh_init_forward_permissions(ssh, "permitremoteopen",
1929 	    options.permitted_remote_opens,
1930 	    options.num_permitted_remote_opens);
1931 
1932 	if (options.exit_on_forward_failure)
1933 		forward_confirms_pending = 0; /* track pending requests */
1934 	/* Initiate local TCP/IP port forwardings. */
1935 	for (i = 0; i < options.num_local_forwards; i++) {
1936 		debug("Local connections to %.200s:%d forwarded to remote "
1937 		    "address %.200s:%d",
1938 		    (options.local_forwards[i].listen_path != NULL) ?
1939 		    options.local_forwards[i].listen_path :
1940 		    (options.local_forwards[i].listen_host == NULL) ?
1941 		    (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1942 		    options.local_forwards[i].listen_host,
1943 		    options.local_forwards[i].listen_port,
1944 		    (options.local_forwards[i].connect_path != NULL) ?
1945 		    options.local_forwards[i].connect_path :
1946 		    options.local_forwards[i].connect_host,
1947 		    options.local_forwards[i].connect_port);
1948 		success += channel_setup_local_fwd_listener(ssh,
1949 		    &options.local_forwards[i], &options.fwd_opts);
1950 	}
1951 	if (i > 0 && success != i && options.exit_on_forward_failure)
1952 		fatal("Could not request local forwarding.");
1953 	if (i > 0 && success == 0)
1954 		error("Could not request local forwarding.");
1955 
1956 	/* Initiate remote TCP/IP port forwardings. */
1957 	for (i = 0; i < options.num_remote_forwards; i++) {
1958 		debug("Remote connections from %.200s:%d forwarded to "
1959 		    "local address %.200s:%d",
1960 		    (options.remote_forwards[i].listen_path != NULL) ?
1961 		    options.remote_forwards[i].listen_path :
1962 		    (options.remote_forwards[i].listen_host == NULL) ?
1963 		    "LOCALHOST" : options.remote_forwards[i].listen_host,
1964 		    options.remote_forwards[i].listen_port,
1965 		    (options.remote_forwards[i].connect_path != NULL) ?
1966 		    options.remote_forwards[i].connect_path :
1967 		    options.remote_forwards[i].connect_host,
1968 		    options.remote_forwards[i].connect_port);
1969 		if ((options.remote_forwards[i].handle =
1970 		    channel_request_remote_forwarding(ssh,
1971 		    &options.remote_forwards[i])) >= 0) {
1972 			client_register_global_confirm(
1973 			    ssh_confirm_remote_forward,
1974 			    &options.remote_forwards[i]);
1975 			forward_confirms_pending++;
1976 		} else if (options.exit_on_forward_failure)
1977 			fatal("Could not request remote forwarding.");
1978 		else
1979 			logit("Warning: Could not request remote forwarding.");
1980 	}
1981 
1982 	/* Initiate tunnel forwarding. */
1983 	if (options.tun_open != SSH_TUNMODE_NO) {
1984 		if ((*ifname = client_request_tun_fwd(ssh,
1985 		    options.tun_open, options.tun_local,
1986 		    options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
1987 			forward_confirms_pending++;
1988 		else if (options.exit_on_forward_failure)
1989 			fatal("Could not request tunnel forwarding.");
1990 		else
1991 			error("Could not request tunnel forwarding.");
1992 	}
1993 	if (forward_confirms_pending > 0) {
1994 		debug_f("expecting replies for %d forwards",
1995 		    forward_confirms_pending);
1996 	}
1997 }
1998 
1999 static void
2000 check_agent_present(void)
2001 {
2002 	int r;
2003 
2004 	if (options.forward_agent) {
2005 		/* Clear agent forwarding if we don't have an agent. */
2006 		if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2007 			options.forward_agent = 0;
2008 			if (r != SSH_ERR_AGENT_NOT_PRESENT)
2009 				debug_r(r, "ssh_get_authentication_socket");
2010 		}
2011 	}
2012 }
2013 
2014 static void
2015 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2016 {
2017 	extern char **environ;
2018 	const char *display, *term;
2019 	int r, interactive = tty_flag;
2020 	char *proto = NULL, *data = NULL;
2021 
2022 	if (!success)
2023 		return; /* No need for error message, channels code sends one */
2024 
2025 	display = getenv("DISPLAY");
2026 	if (display == NULL && options.forward_x11)
2027 		debug("X11 forwarding requested but DISPLAY not set");
2028 	if (options.forward_x11 && client_x11_get_proto(ssh, display,
2029 	    options.xauth_location, options.forward_x11_trusted,
2030 	    options.forward_x11_timeout, &proto, &data) == 0) {
2031 		/* Request forwarding with authentication spoofing. */
2032 		debug("Requesting X11 forwarding with authentication "
2033 		    "spoofing.");
2034 		x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2035 		    data, 1);
2036 		client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2037 		/* XXX exit_on_forward_failure */
2038 		interactive = 1;
2039 	}
2040 
2041 	check_agent_present();
2042 	if (options.forward_agent) {
2043 		debug("Requesting authentication agent forwarding.");
2044 		channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2045 		if ((r = sshpkt_send(ssh)) != 0)
2046 			fatal_fr(r, "send packet");
2047 	}
2048 
2049 	/* Tell the packet module whether this is an interactive session. */
2050 	ssh_packet_set_interactive(ssh, interactive,
2051 	    options.ip_qos_interactive, options.ip_qos_bulk);
2052 
2053 	if ((term = lookup_env_in_list("TERM", options.setenv,
2054 	    options.num_setenv)) == NULL || *term == '\0')
2055 		term = getenv("TERM");
2056 	client_session2_setup(ssh, id, tty_flag,
2057 	    options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2058 	    NULL, fileno(stdin), command, environ);
2059 }
2060 
2061 /* open new channel for a session */
2062 static int
2063 ssh_session2_open(struct ssh *ssh)
2064 {
2065 	Channel *c;
2066 	int window, packetmax, in, out, err;
2067 
2068 	if (options.stdin_null) {
2069 		in = open(_PATH_DEVNULL, O_RDONLY);
2070 	} else {
2071 		in = dup(STDIN_FILENO);
2072 	}
2073 	out = dup(STDOUT_FILENO);
2074 	err = dup(STDERR_FILENO);
2075 
2076 	if (in == -1 || out == -1 || err == -1)
2077 		fatal("dup() in/out/err failed");
2078 
2079 	window = CHAN_SES_WINDOW_DEFAULT;
2080 	packetmax = CHAN_SES_PACKET_DEFAULT;
2081 	if (tty_flag) {
2082 		window >>= 1;
2083 		packetmax >>= 1;
2084 	}
2085 	c = channel_new(ssh,
2086 	    "session", SSH_CHANNEL_OPENING, in, out, err,
2087 	    window, packetmax, CHAN_EXTENDED_WRITE,
2088 	    "client-session", CHANNEL_NONBLOCK_STDIO);
2089 
2090 	debug3_f("channel_new: %d", c->self);
2091 
2092 	channel_send_open(ssh, c->self);
2093 	if (options.session_type != SESSION_TYPE_NONE)
2094 		channel_register_open_confirm(ssh, c->self,
2095 		    ssh_session2_setup, NULL);
2096 
2097 	return c->self;
2098 }
2099 
2100 static int
2101 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2102 {
2103 	int r, id = -1;
2104 	char *cp, *tun_fwd_ifname = NULL;
2105 
2106 	/* XXX should be pre-session */
2107 	if (!options.control_persist)
2108 		ssh_init_stdio_forwarding(ssh);
2109 
2110 	ssh_init_forwarding(ssh, &tun_fwd_ifname);
2111 
2112 	if (options.local_command != NULL) {
2113 		debug3("expanding LocalCommand: %s", options.local_command);
2114 		cp = options.local_command;
2115 		options.local_command = percent_expand(cp,
2116 		    DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2117 		    "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2118 		    (char *)NULL);
2119 		debug3("expanded LocalCommand: %s", options.local_command);
2120 		free(cp);
2121 	}
2122 
2123 	/* Start listening for multiplex clients */
2124 	if (!ssh_packet_get_mux(ssh))
2125 		muxserver_listen(ssh);
2126 
2127 	/*
2128 	 * If we are in control persist mode and have a working mux listen
2129 	 * socket, then prepare to background ourselves and have a foreground
2130 	 * client attach as a control client.
2131 	 * NB. we must save copies of the flags that we override for
2132 	 * the backgrounding, since we defer attachment of the client until
2133 	 * after the connection is fully established (in particular,
2134 	 * async rfwd replies have been received for ExitOnForwardFailure).
2135 	 */
2136 	if (options.control_persist && muxserver_sock != -1) {
2137 		ostdin_null_flag = options.stdin_null;
2138 		osession_type = options.session_type;
2139 		orequest_tty = options.request_tty;
2140 		otty_flag = tty_flag;
2141 		options.stdin_null = 1;
2142 		options.session_type = SESSION_TYPE_NONE;
2143 		tty_flag = 0;
2144 		if (!options.fork_after_authentication &&
2145 		    (osession_type != SESSION_TYPE_NONE ||
2146 		    options.stdio_forward_host != NULL))
2147 			need_controlpersist_detach = 1;
2148 		options.fork_after_authentication = 1;
2149 	}
2150 	/*
2151 	 * ControlPersist mux listen socket setup failed, attempt the
2152 	 * stdio forward setup that we skipped earlier.
2153 	 */
2154 	if (options.control_persist && muxserver_sock == -1)
2155 		ssh_init_stdio_forwarding(ssh);
2156 
2157 	if (options.session_type != SESSION_TYPE_NONE)
2158 		id = ssh_session2_open(ssh);
2159 	else {
2160 		ssh_packet_set_interactive(ssh,
2161 		    options.control_master == SSHCTL_MASTER_NO,
2162 		    options.ip_qos_interactive, options.ip_qos_bulk);
2163 	}
2164 
2165 	/* If we don't expect to open a new session, then disallow it */
2166 	if (options.control_master == SSHCTL_MASTER_NO &&
2167 	    (ssh->compat & SSH_NEW_OPENSSH)) {
2168 		debug("Requesting no-more-sessions@openssh.com");
2169 		if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2170 		    (r = sshpkt_put_cstring(ssh,
2171 		    "no-more-sessions@openssh.com")) != 0 ||
2172 		    (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2173 		    (r = sshpkt_send(ssh)) != 0)
2174 			fatal_fr(r, "send packet");
2175 	}
2176 
2177 	/* Execute a local command */
2178 	if (options.local_command != NULL &&
2179 	    options.permit_local_command)
2180 		ssh_local_cmd(options.local_command);
2181 
2182 	/*
2183 	 * stdout is now owned by the session channel; clobber it here
2184 	 * so future channel closes are propagated to the local fd.
2185 	 * NB. this can only happen after LocalCommand has completed,
2186 	 * as it may want to write to stdout.
2187 	 */
2188 	if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2189 		error_f("stdfd_devnull failed");
2190 
2191 	/*
2192 	 * If requested and we are not interested in replies to remote
2193 	 * forwarding requests, then let ssh continue in the background.
2194 	 */
2195 	if (options.fork_after_authentication) {
2196 		if (options.exit_on_forward_failure &&
2197 		    options.num_remote_forwards > 0) {
2198 			debug("deferring postauth fork until remote forward "
2199 			    "confirmation received");
2200 		} else
2201 			fork_postauth();
2202 	}
2203 
2204 	return client_loop(ssh, tty_flag, tty_flag ?
2205 	    options.escape_char : SSH_ESCAPECHAR_NONE, id);
2206 }
2207 
2208 /* Loads all IdentityFile and CertificateFile keys */
2209 static void
2210 load_public_identity_files(const struct ssh_conn_info *cinfo)
2211 {
2212 	char *filename, *cp;
2213 	struct sshkey *public;
2214 	int i;
2215 	u_int n_ids, n_certs;
2216 	char *identity_files[SSH_MAX_IDENTITY_FILES];
2217 	struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2218 	int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2219 	char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2220 	struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2221 	int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2222 #ifdef ENABLE_PKCS11
2223 	struct sshkey **keys = NULL;
2224 	char **comments = NULL;
2225 	int nkeys;
2226 #endif /* PKCS11 */
2227 
2228 	n_ids = n_certs = 0;
2229 	memset(identity_files, 0, sizeof(identity_files));
2230 	memset(identity_keys, 0, sizeof(identity_keys));
2231 	memset(identity_file_userprovided, 0,
2232 	    sizeof(identity_file_userprovided));
2233 	memset(certificate_files, 0, sizeof(certificate_files));
2234 	memset(certificates, 0, sizeof(certificates));
2235 	memset(certificate_file_userprovided, 0,
2236 	    sizeof(certificate_file_userprovided));
2237 
2238 #ifdef ENABLE_PKCS11
2239 	if (options.pkcs11_provider != NULL &&
2240 	    options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2241 	    (pkcs11_init(!options.batch_mode) == 0) &&
2242 	    (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2243 	    &keys, &comments)) > 0) {
2244 		for (i = 0; i < nkeys; i++) {
2245 			if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2246 				sshkey_free(keys[i]);
2247 				free(comments[i]);
2248 				continue;
2249 			}
2250 			identity_keys[n_ids] = keys[i];
2251 			identity_files[n_ids] = comments[i]; /* transferred */
2252 			n_ids++;
2253 		}
2254 		free(keys);
2255 		free(comments);
2256 	}
2257 #endif /* ENABLE_PKCS11 */
2258 	for (i = 0; i < options.num_identity_files; i++) {
2259 		if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2260 		    strcasecmp(options.identity_files[i], "none") == 0) {
2261 			free(options.identity_files[i]);
2262 			options.identity_files[i] = NULL;
2263 			continue;
2264 		}
2265 		cp = tilde_expand_filename(options.identity_files[i], getuid());
2266 		filename = default_client_percent_dollar_expand(cp, cinfo);
2267 		free(cp);
2268 		check_load(sshkey_load_public(filename, &public, NULL),
2269 		    &public, filename, "pubkey");
2270 		debug("identity file %s type %d", filename,
2271 		    public ? public->type : -1);
2272 		free(options.identity_files[i]);
2273 		identity_files[n_ids] = filename;
2274 		identity_keys[n_ids] = public;
2275 		identity_file_userprovided[n_ids] =
2276 		    options.identity_file_userprovided[i];
2277 		if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2278 			continue;
2279 
2280 		/*
2281 		 * If no certificates have been explicitly listed then try
2282 		 * to add the default certificate variant too.
2283 		 */
2284 		if (options.num_certificate_files != 0)
2285 			continue;
2286 		xasprintf(&cp, "%s-cert", filename);
2287 		check_load(sshkey_load_public(cp, &public, NULL),
2288 		    &public, filename, "pubkey");
2289 		debug("identity file %s type %d", cp,
2290 		    public ? public->type : -1);
2291 		if (public == NULL) {
2292 			free(cp);
2293 			continue;
2294 		}
2295 		if (!sshkey_is_cert(public)) {
2296 			debug_f("key %s type %s is not a certificate",
2297 			    cp, sshkey_type(public));
2298 			sshkey_free(public);
2299 			free(cp);
2300 			continue;
2301 		}
2302 		/* NB. leave filename pointing to private key */
2303 		identity_files[n_ids] = xstrdup(filename);
2304 		identity_keys[n_ids] = public;
2305 		identity_file_userprovided[n_ids] =
2306 		    options.identity_file_userprovided[i];
2307 		n_ids++;
2308 	}
2309 
2310 	if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2311 		fatal_f("too many certificates");
2312 	for (i = 0; i < options.num_certificate_files; i++) {
2313 		cp = tilde_expand_filename(options.certificate_files[i],
2314 		    getuid());
2315 		filename = default_client_percent_dollar_expand(cp, cinfo);
2316 		free(cp);
2317 
2318 		check_load(sshkey_load_public(filename, &public, NULL),
2319 		    &public, filename, "certificate");
2320 		debug("certificate file %s type %d", filename,
2321 		    public ? public->type : -1);
2322 		free(options.certificate_files[i]);
2323 		options.certificate_files[i] = NULL;
2324 		if (public == NULL) {
2325 			free(filename);
2326 			continue;
2327 		}
2328 		if (!sshkey_is_cert(public)) {
2329 			debug_f("key %s type %s is not a certificate",
2330 			    filename, sshkey_type(public));
2331 			sshkey_free(public);
2332 			free(filename);
2333 			continue;
2334 		}
2335 		certificate_files[n_certs] = filename;
2336 		certificates[n_certs] = public;
2337 		certificate_file_userprovided[n_certs] =
2338 		    options.certificate_file_userprovided[i];
2339 		++n_certs;
2340 	}
2341 
2342 	options.num_identity_files = n_ids;
2343 	memcpy(options.identity_files, identity_files, sizeof(identity_files));
2344 	memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2345 	memcpy(options.identity_file_userprovided,
2346 	    identity_file_userprovided, sizeof(identity_file_userprovided));
2347 
2348 	options.num_certificate_files = n_certs;
2349 	memcpy(options.certificate_files,
2350 	    certificate_files, sizeof(certificate_files));
2351 	memcpy(options.certificates, certificates, sizeof(certificates));
2352 	memcpy(options.certificate_file_userprovided,
2353 	    certificate_file_userprovided,
2354 	    sizeof(certificate_file_userprovided));
2355 }
2356 
2357 static void
2358 main_sigchld_handler(int sig)
2359 {
2360 	int save_errno = errno;
2361 	pid_t pid;
2362 	int status;
2363 
2364 	while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2365 	    (pid == -1 && errno == EINTR))
2366 		;
2367 	errno = save_errno;
2368 }
2369