xref: /openssh-portable/ssh.c (revision 4d28fa78)
1 /* $OpenBSD: ssh.c,v 1.505 2019/06/28 13:35:04 deraadt 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 SSL 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 "includes.h"
44 
45 #include <sys/types.h>
46 #ifdef HAVE_SYS_STAT_H
47 # include <sys/stat.h>
48 #endif
49 #include <sys/resource.h>
50 #include <sys/ioctl.h>
51 #include <sys/socket.h>
52 #include <sys/wait.h>
53 
54 #include <ctype.h>
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <netdb.h>
58 #ifdef HAVE_PATHS_H
59 #include <paths.h>
60 #endif
61 #include <pwd.h>
62 #include <signal.h>
63 #include <stdarg.h>
64 #include <stddef.h>
65 #include <stdio.h>
66 #include <stdlib.h>
67 #include <string.h>
68 #include <unistd.h>
69 #include <limits.h>
70 #include <locale.h>
71 
72 #include <netinet/in.h>
73 #include <arpa/inet.h>
74 
75 #ifdef WITH_OPENSSL
76 #include <openssl/evp.h>
77 #include <openssl/err.h>
78 #endif
79 #include "openbsd-compat/openssl-compat.h"
80 #include "openbsd-compat/sys-queue.h"
81 
82 #include "xmalloc.h"
83 #include "ssh.h"
84 #include "ssh2.h"
85 #include "canohost.h"
86 #include "compat.h"
87 #include "cipher.h"
88 #include "digest.h"
89 #include "packet.h"
90 #include "sshbuf.h"
91 #include "channels.h"
92 #include "sshkey.h"
93 #include "authfd.h"
94 #include "authfile.h"
95 #include "pathnames.h"
96 #include "dispatch.h"
97 #include "clientloop.h"
98 #include "log.h"
99 #include "misc.h"
100 #include "readconf.h"
101 #include "sshconnect.h"
102 #include "kex.h"
103 #include "mac.h"
104 #include "sshpty.h"
105 #include "match.h"
106 #include "msg.h"
107 #include "version.h"
108 #include "ssherr.h"
109 #include "myproposal.h"
110 #include "utf8.h"
111 
112 #ifdef ENABLE_PKCS11
113 #include "ssh-pkcs11.h"
114 #endif
115 
116 extern char *__progname;
117 
118 /* Saves a copy of argv for setproctitle emulation */
119 #ifndef HAVE_SETPROCTITLE
120 static char **saved_av;
121 #endif
122 
123 /* Flag indicating whether debug mode is on.  May be set on the command line. */
124 int debug_flag = 0;
125 
126 /* Flag indicating whether a tty should be requested */
127 int tty_flag = 0;
128 
129 /* don't exec a shell */
130 int no_shell_flag = 0;
131 
132 /*
133  * Flag indicating that nothing should be read from stdin.  This can be set
134  * on the command line.
135  */
136 int stdin_null_flag = 0;
137 
138 /*
139  * Flag indicating that the current process should be backgrounded and
140  * a new slave launched in the foreground for ControlPersist.
141  */
142 int need_controlpersist_detach = 0;
143 
144 /* Copies of flags for ControlPersist foreground slave */
145 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
146 
147 /*
148  * Flag indicating that ssh should fork after authentication.  This is useful
149  * so that the passphrase can be entered manually, and then ssh goes to the
150  * background.
151  */
152 int fork_after_authentication_flag = 0;
153 
154 /*
155  * General data structure for command line options and options configurable
156  * in configuration files.  See readconf.h.
157  */
158 Options options;
159 
160 /* optional user configfile */
161 char *config = NULL;
162 
163 /*
164  * Name of the host we are connecting to.  This is the name given on the
165  * command line, or the Hostname specified for the user-supplied name in a
166  * configuration file.
167  */
168 char *host;
169 
170 /* Various strings used to to percent_expand() arguments */
171 static char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
172 static char uidstr[32], *host_arg, *conn_hash_hex;
173 
174 /* socket address the host resolves to */
175 struct sockaddr_storage hostaddr;
176 
177 /* Private host keys. */
178 Sensitive sensitive_data;
179 
180 /* command to be executed */
181 struct sshbuf *command;
182 
183 /* Should we execute a command or invoke a subsystem? */
184 int subsystem_flag = 0;
185 
186 /* # of replies received for global requests */
187 static int remote_forward_confirms_received = 0;
188 
189 /* mux.c */
190 extern int muxserver_sock;
191 extern u_int muxclient_command;
192 
193 /* Prints a help message to the user.  This function never returns. */
194 
195 static void
usage(void)196 usage(void)
197 {
198 	fprintf(stderr,
199 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
200 "           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
201 "           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
202 "           [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
203 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
204 "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
205 "           [-w local_tun[:remote_tun]] destination [command]\n"
206 	);
207 	exit(255);
208 }
209 
210 static int ssh_session2(struct ssh *, struct passwd *);
211 static void load_public_identity_files(struct passwd *);
212 static void main_sigchld_handler(int);
213 
214 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
215 static void
tilde_expand_paths(char ** paths,u_int num_paths)216 tilde_expand_paths(char **paths, u_int num_paths)
217 {
218 	u_int i;
219 	char *cp;
220 
221 	for (i = 0; i < num_paths; i++) {
222 		cp = tilde_expand_filename(paths[i], getuid());
223 		free(paths[i]);
224 		paths[i] = cp;
225 	}
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 *
resolve_host(const char * name,int port,int logerr,char * cname,size_t clen)235 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
236 {
237 	char strport[NI_MAXSERV];
238 	struct addrinfo hints, *res;
239 	int gaierr;
240 	LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
241 
242 	if (port <= 0)
243 		port = default_ssh_port();
244 
245 	snprintf(strport, sizeof strport, "%d", port);
246 	memset(&hints, 0, sizeof(hints));
247 	hints.ai_family = options.address_family == -1 ?
248 	    AF_UNSPEC : options.address_family;
249 	hints.ai_socktype = SOCK_STREAM;
250 	if (cname != NULL)
251 		hints.ai_flags = AI_CANONNAME;
252 	if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
253 		if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
254 			loglevel = SYSLOG_LEVEL_ERROR;
255 		do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
256 		    __progname, name, ssh_gai_strerror(gaierr));
257 		return NULL;
258 	}
259 	if (cname != NULL && res->ai_canonname != NULL) {
260 		if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
261 			error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
262 			    __func__, name,  res->ai_canonname, (u_long)clen);
263 			if (clen > 0)
264 				*cname = '\0';
265 		}
266 	}
267 	return res;
268 }
269 
270 /* Returns non-zero if name can only be an address and not a hostname */
271 static int
is_addr_fast(const char * name)272 is_addr_fast(const char *name)
273 {
274 	return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
275 	    strspn(name, "0123456789.") == strlen(name));
276 }
277 
278 /* Returns non-zero if name represents a valid, single address */
279 static int
is_addr(const char * name)280 is_addr(const char *name)
281 {
282 	char strport[NI_MAXSERV];
283 	struct addrinfo hints, *res;
284 
285 	if (is_addr_fast(name))
286 		return 1;
287 
288 	snprintf(strport, sizeof strport, "%u", default_ssh_port());
289 	memset(&hints, 0, sizeof(hints));
290 	hints.ai_family = options.address_family == -1 ?
291 	    AF_UNSPEC : options.address_family;
292 	hints.ai_socktype = SOCK_STREAM;
293 	hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
294 	if (getaddrinfo(name, strport, &hints, &res) != 0)
295 		return 0;
296 	if (res == NULL || res->ai_next != NULL) {
297 		freeaddrinfo(res);
298 		return 0;
299 	}
300 	freeaddrinfo(res);
301 	return 1;
302 }
303 
304 /*
305  * Attempt to resolve a numeric host address / port to a single address.
306  * Returns a canonical address string.
307  * Returns NULL on failure.
308  * NB. this function must operate with a options having undefined members.
309  */
310 static struct addrinfo *
resolve_addr(const char * name,int port,char * caddr,size_t clen)311 resolve_addr(const char *name, int port, char *caddr, size_t clen)
312 {
313 	char addr[NI_MAXHOST], strport[NI_MAXSERV];
314 	struct addrinfo hints, *res;
315 	int gaierr;
316 
317 	if (port <= 0)
318 		port = default_ssh_port();
319 	snprintf(strport, sizeof strport, "%u", port);
320 	memset(&hints, 0, sizeof(hints));
321 	hints.ai_family = options.address_family == -1 ?
322 	    AF_UNSPEC : options.address_family;
323 	hints.ai_socktype = SOCK_STREAM;
324 	hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
325 	if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
326 		debug2("%s: could not resolve name %.100s as address: %s",
327 		    __func__, name, ssh_gai_strerror(gaierr));
328 		return NULL;
329 	}
330 	if (res == NULL) {
331 		debug("%s: getaddrinfo %.100s returned no addresses",
332 		 __func__, name);
333 		return NULL;
334 	}
335 	if (res->ai_next != NULL) {
336 		debug("%s: getaddrinfo %.100s returned multiple addresses",
337 		    __func__, name);
338 		goto fail;
339 	}
340 	if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
341 	    addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
342 		debug("%s: Could not format address for name %.100s: %s",
343 		    __func__, name, ssh_gai_strerror(gaierr));
344 		goto fail;
345 	}
346 	if (strlcpy(caddr, addr, clen) >= clen) {
347 		error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
348 		    __func__, name,  addr, (u_long)clen);
349 		if (clen > 0)
350 			*caddr = '\0';
351  fail:
352 		freeaddrinfo(res);
353 		return NULL;
354 	}
355 	return res;
356 }
357 
358 /*
359  * Check whether the cname is a permitted replacement for the hostname
360  * and perform the replacement if it is.
361  * NB. this function must operate with a options having undefined members.
362  */
363 static int
check_follow_cname(int direct,char ** namep,const char * cname)364 check_follow_cname(int direct, char **namep, const char *cname)
365 {
366 	int i;
367 	struct allowed_cname *rule;
368 
369 	if (*cname == '\0' || options.num_permitted_cnames == 0 ||
370 	    strcmp(*namep, cname) == 0)
371 		return 0;
372 	if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
373 		return 0;
374 	/*
375 	 * Don't attempt to canonicalize names that will be interpreted by
376 	 * a proxy or jump host unless the user specifically requests so.
377 	 */
378 	if (!direct &&
379 	    options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
380 		return 0;
381 	debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
382 	for (i = 0; i < options.num_permitted_cnames; i++) {
383 		rule = options.permitted_cnames + i;
384 		if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
385 		    match_pattern_list(cname, rule->target_list, 1) != 1)
386 			continue;
387 		verbose("Canonicalized DNS aliased hostname "
388 		    "\"%s\" => \"%s\"", *namep, cname);
389 		free(*namep);
390 		*namep = xstrdup(cname);
391 		return 1;
392 	}
393 	return 0;
394 }
395 
396 /*
397  * Attempt to resolve the supplied hostname after applying the user's
398  * canonicalization rules. Returns the address list for the host or NULL
399  * if no name was found after canonicalization.
400  * NB. this function must operate with a options having undefined members.
401  */
402 static struct addrinfo *
resolve_canonicalize(char ** hostp,int port)403 resolve_canonicalize(char **hostp, int port)
404 {
405 	int i, direct, ndots;
406 	char *cp, *fullhost, newname[NI_MAXHOST];
407 	struct addrinfo *addrs;
408 
409 	/*
410 	 * Attempt to canonicalise addresses, regardless of
411 	 * whether hostname canonicalisation was requested
412 	 */
413 	if ((addrs = resolve_addr(*hostp, port,
414 	    newname, sizeof(newname))) != NULL) {
415 		debug2("%s: hostname %.100s is address", __func__, *hostp);
416 		if (strcasecmp(*hostp, newname) != 0) {
417 			debug2("%s: canonicalised address \"%s\" => \"%s\"",
418 			    __func__, *hostp, newname);
419 			free(*hostp);
420 			*hostp = xstrdup(newname);
421 		}
422 		return addrs;
423 	}
424 
425 	/*
426 	 * If this looks like an address but didn't parse as one, it might
427 	 * be an address with an invalid interface scope. Skip further
428 	 * attempts at canonicalisation.
429 	 */
430 	if (is_addr_fast(*hostp)) {
431 		debug("%s: hostname %.100s is an unrecognised address",
432 		    __func__, *hostp);
433 		return NULL;
434 	}
435 
436 	if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
437 		return NULL;
438 
439 	/*
440 	 * Don't attempt to canonicalize names that will be interpreted by
441 	 * a proxy unless the user specifically requests so.
442 	 */
443 	direct = option_clear_or_none(options.proxy_command) &&
444 	    options.jump_host == NULL;
445 	if (!direct &&
446 	    options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
447 		return NULL;
448 
449 	/* If domain name is anchored, then resolve it now */
450 	if ((*hostp)[strlen(*hostp) - 1] == '.') {
451 		debug3("%s: name is fully qualified", __func__);
452 		fullhost = xstrdup(*hostp);
453 		if ((addrs = resolve_host(fullhost, port, 0,
454 		    newname, sizeof(newname))) != NULL)
455 			goto found;
456 		free(fullhost);
457 		goto notfound;
458 	}
459 
460 	/* Don't apply canonicalization to sufficiently-qualified hostnames */
461 	ndots = 0;
462 	for (cp = *hostp; *cp != '\0'; cp++) {
463 		if (*cp == '.')
464 			ndots++;
465 	}
466 	if (ndots > options.canonicalize_max_dots) {
467 		debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
468 		    __func__, *hostp, options.canonicalize_max_dots);
469 		return NULL;
470 	}
471 	/* Attempt each supplied suffix */
472 	for (i = 0; i < options.num_canonical_domains; i++) {
473 		*newname = '\0';
474 		xasprintf(&fullhost, "%s.%s.", *hostp,
475 		    options.canonical_domains[i]);
476 		debug3("%s: attempting \"%s\" => \"%s\"", __func__,
477 		    *hostp, fullhost);
478 		if ((addrs = resolve_host(fullhost, port, 0,
479 		    newname, sizeof(newname))) == NULL) {
480 			free(fullhost);
481 			continue;
482 		}
483  found:
484 		/* Remove trailing '.' */
485 		fullhost[strlen(fullhost) - 1] = '\0';
486 		/* Follow CNAME if requested */
487 		if (!check_follow_cname(direct, &fullhost, newname)) {
488 			debug("Canonicalized hostname \"%s\" => \"%s\"",
489 			    *hostp, fullhost);
490 		}
491 		free(*hostp);
492 		*hostp = fullhost;
493 		return addrs;
494 	}
495  notfound:
496 	if (!options.canonicalize_fallback_local)
497 		fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
498 	debug2("%s: host %s not found in any suffix", __func__, *hostp);
499 	return NULL;
500 }
501 
502 /*
503  * Check the result of hostkey loading, ignoring some errors and
504  * fatal()ing for others.
505  */
506 static void
check_load(int r,const char * path,const char * message)507 check_load(int r, const char *path, const char *message)
508 {
509 	switch (r) {
510 	case 0:
511 		break;
512 	case SSH_ERR_INTERNAL_ERROR:
513 	case SSH_ERR_ALLOC_FAIL:
514 		fatal("load %s \"%s\": %s", message, path, ssh_err(r));
515 	case SSH_ERR_SYSTEM_ERROR:
516 		/* Ignore missing files */
517 		if (errno == ENOENT)
518 			break;
519 		/* FALLTHROUGH */
520 	default:
521 		error("load %s \"%s\": %s", message, path, ssh_err(r));
522 		break;
523 	}
524 }
525 
526 /*
527  * Read per-user configuration file.  Ignore the system wide config
528  * file if the user specifies a config file on the command line.
529  */
530 static void
process_config_files(const char * host_name,struct passwd * pw,int final_pass,int * want_final_pass)531 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
532     int *want_final_pass)
533 {
534 	char buf[PATH_MAX];
535 	int r;
536 
537 	if (config != NULL) {
538 		if (strcasecmp(config, "none") != 0 &&
539 		    !read_config_file(config, pw, host, host_name, &options,
540 		    SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
541 		    want_final_pass))
542 			fatal("Can't open user config file %.100s: "
543 			    "%.100s", config, strerror(errno));
544 	} else {
545 		r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
546 		    _PATH_SSH_USER_CONFFILE);
547 		if (r > 0 && (size_t)r < sizeof(buf))
548 			(void)read_config_file(buf, pw, host, host_name,
549 			    &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
550 			    (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
551 
552 		/* Read systemwide configuration file after user config. */
553 		(void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
554 		    host, host_name, &options,
555 		    final_pass ? SSHCONF_FINAL : 0, want_final_pass);
556 	}
557 }
558 
559 /* Rewrite the port number in an addrinfo list of addresses */
560 static void
set_addrinfo_port(struct addrinfo * addrs,int port)561 set_addrinfo_port(struct addrinfo *addrs, int port)
562 {
563 	struct addrinfo *addr;
564 
565 	for (addr = addrs; addr != NULL; addr = addr->ai_next) {
566 		switch (addr->ai_family) {
567 		case AF_INET:
568 			((struct sockaddr_in *)addr->ai_addr)->
569 			    sin_port = htons(port);
570 			break;
571 		case AF_INET6:
572 			((struct sockaddr_in6 *)addr->ai_addr)->
573 			    sin6_port = htons(port);
574 			break;
575 		}
576 	}
577 }
578 
579 /*
580  * Main program for the ssh client.
581  */
582 int
main(int ac,char ** av)583 main(int ac, char **av)
584 {
585 	struct ssh *ssh = NULL;
586 	int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
587 	int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
588 	char *p, *cp, *line, *argv0, buf[PATH_MAX], *logfile;
589 	char cname[NI_MAXHOST];
590 	struct stat st;
591 	struct passwd *pw;
592 	extern int optind, optreset;
593 	extern char *optarg;
594 	struct Forward fwd;
595 	struct addrinfo *addrs = NULL;
596 	struct ssh_digest_ctx *md;
597 	u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
598 
599 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
600 	sanitise_stdfd();
601 
602 	__progname = ssh_get_progname(av[0]);
603 
604 #ifndef HAVE_SETPROCTITLE
605 	/* Prepare for later setproctitle emulation */
606 	/* Save argv so it isn't clobbered by setproctitle() emulation */
607 	saved_av = xcalloc(ac + 1, sizeof(*saved_av));
608 	for (i = 0; i < ac; i++)
609 		saved_av[i] = xstrdup(av[i]);
610 	saved_av[i] = NULL;
611 	compat_init_setproctitle(ac, av);
612 	av = saved_av;
613 #endif
614 
615 	seed_rng();
616 
617 	/*
618 	 * Discard other fds that are hanging around. These can cause problem
619 	 * with backgrounded ssh processes started by ControlPersist.
620 	 */
621 	closefrom(STDERR_FILENO + 1);
622 
623 	/* Get user data. */
624 	pw = getpwuid(getuid());
625 	if (!pw) {
626 		logit("No user exists for uid %lu", (u_long)getuid());
627 		exit(255);
628 	}
629 	/* Take a copy of the returned structure. */
630 	pw = pwcopy(pw);
631 
632 	/*
633 	 * Set our umask to something reasonable, as some files are created
634 	 * with the default umask.  This will make them world-readable but
635 	 * writable only by the owner, which is ok for all files for which we
636 	 * don't set the modes explicitly.
637 	 */
638 	umask(022);
639 
640 	msetlocale();
641 
642 	/*
643 	 * Initialize option structure to indicate that no values have been
644 	 * set.
645 	 */
646 	initialize_options(&options);
647 
648 	/*
649 	 * Prepare main ssh transport/connection structures
650 	 */
651 	if ((ssh = ssh_alloc_session_state()) == NULL)
652 		fatal("Couldn't allocate session state");
653 	channel_init_channels(ssh);
654 
655 	/* Parse command-line arguments. */
656 	host = NULL;
657 	use_syslog = 0;
658 	logfile = NULL;
659 	argv0 = av[0];
660 
661  again:
662 	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
663 	    "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
664 		switch (opt) {
665 		case '1':
666 			fatal("SSH protocol v.1 is no longer supported");
667 			break;
668 		case '2':
669 			/* Ignored */
670 			break;
671 		case '4':
672 			options.address_family = AF_INET;
673 			break;
674 		case '6':
675 			options.address_family = AF_INET6;
676 			break;
677 		case 'n':
678 			stdin_null_flag = 1;
679 			break;
680 		case 'f':
681 			fork_after_authentication_flag = 1;
682 			stdin_null_flag = 1;
683 			break;
684 		case 'x':
685 			options.forward_x11 = 0;
686 			break;
687 		case 'X':
688 			options.forward_x11 = 1;
689 			break;
690 		case 'y':
691 			use_syslog = 1;
692 			break;
693 		case 'E':
694 			logfile = optarg;
695 			break;
696 		case 'G':
697 			config_test = 1;
698 			break;
699 		case 'Y':
700 			options.forward_x11 = 1;
701 			options.forward_x11_trusted = 1;
702 			break;
703 		case 'g':
704 			options.fwd_opts.gateway_ports = 1;
705 			break;
706 		case 'O':
707 			if (options.stdio_forward_host != NULL)
708 				fatal("Cannot specify multiplexing "
709 				    "command with -W");
710 			else if (muxclient_command != 0)
711 				fatal("Multiplexing command already specified");
712 			if (strcmp(optarg, "check") == 0)
713 				muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
714 			else if (strcmp(optarg, "forward") == 0)
715 				muxclient_command = SSHMUX_COMMAND_FORWARD;
716 			else if (strcmp(optarg, "exit") == 0)
717 				muxclient_command = SSHMUX_COMMAND_TERMINATE;
718 			else if (strcmp(optarg, "stop") == 0)
719 				muxclient_command = SSHMUX_COMMAND_STOP;
720 			else if (strcmp(optarg, "cancel") == 0)
721 				muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
722 			else if (strcmp(optarg, "proxy") == 0)
723 				muxclient_command = SSHMUX_COMMAND_PROXY;
724 			else
725 				fatal("Invalid multiplex command.");
726 			break;
727 		case 'P':	/* deprecated */
728 			break;
729 		case 'Q':
730 			cp = NULL;
731 			if (strcmp(optarg, "cipher") == 0)
732 				cp = cipher_alg_list('\n', 0);
733 			else if (strcmp(optarg, "cipher-auth") == 0)
734 				cp = cipher_alg_list('\n', 1);
735 			else if (strcmp(optarg, "mac") == 0)
736 				cp = mac_alg_list('\n');
737 			else if (strcmp(optarg, "kex") == 0)
738 				cp = kex_alg_list('\n');
739 			else if (strcmp(optarg, "key") == 0)
740 				cp = sshkey_alg_list(0, 0, 0, '\n');
741 			else if (strcmp(optarg, "key-cert") == 0)
742 				cp = sshkey_alg_list(1, 0, 0, '\n');
743 			else if (strcmp(optarg, "key-plain") == 0)
744 				cp = sshkey_alg_list(0, 1, 0, '\n');
745 			else if (strcmp(optarg, "sig") == 0)
746 				cp = sshkey_alg_list(0, 1, 1, '\n');
747 			else if (strcmp(optarg, "protocol-version") == 0)
748 				cp = xstrdup("2");
749 			else if (strcmp(optarg, "help") == 0) {
750 				cp = xstrdup(
751 				    "cipher\ncipher-auth\nkex\nkey\n"
752 				    "key-cert\nkey-plain\nmac\n"
753 				    "protocol-version\nsig");
754 			}
755 			if (cp == NULL)
756 				fatal("Unsupported query \"%s\"", optarg);
757 			printf("%s\n", cp);
758 			free(cp);
759 			exit(0);
760 			break;
761 		case 'a':
762 			options.forward_agent = 0;
763 			break;
764 		case 'A':
765 			options.forward_agent = 1;
766 			break;
767 		case 'k':
768 			options.gss_deleg_creds = 0;
769 			break;
770 		case 'K':
771 			options.gss_authentication = 1;
772 			options.gss_deleg_creds = 1;
773 			break;
774 		case 'i':
775 			p = tilde_expand_filename(optarg, getuid());
776 			if (stat(p, &st) == -1)
777 				fprintf(stderr, "Warning: Identity file %s "
778 				    "not accessible: %s.\n", p,
779 				    strerror(errno));
780 			else
781 				add_identity_file(&options, NULL, p, 1);
782 			free(p);
783 			break;
784 		case 'I':
785 #ifdef ENABLE_PKCS11
786 			free(options.pkcs11_provider);
787 			options.pkcs11_provider = xstrdup(optarg);
788 #else
789 			fprintf(stderr, "no support for PKCS#11.\n");
790 #endif
791 			break;
792 		case 'J':
793 			if (options.jump_host != NULL) {
794 				fatal("Only a single -J option is permitted "
795 				    "(use commas to separate multiple "
796 				    "jump hops)");
797 			}
798 			if (options.proxy_command != NULL)
799 				fatal("Cannot specify -J with ProxyCommand");
800 			if (parse_jump(optarg, &options, 1) == -1)
801 				fatal("Invalid -J argument");
802 			options.proxy_command = xstrdup("none");
803 			break;
804 		case 't':
805 			if (options.request_tty == REQUEST_TTY_YES)
806 				options.request_tty = REQUEST_TTY_FORCE;
807 			else
808 				options.request_tty = REQUEST_TTY_YES;
809 			break;
810 		case 'v':
811 			if (debug_flag == 0) {
812 				debug_flag = 1;
813 				options.log_level = SYSLOG_LEVEL_DEBUG1;
814 			} else {
815 				if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
816 					debug_flag++;
817 					options.log_level++;
818 				}
819 			}
820 			break;
821 		case 'V':
822 			fprintf(stderr, "%s, %s\n",
823 			    SSH_RELEASE,
824 #ifdef WITH_OPENSSL
825 			    OpenSSL_version(OPENSSL_VERSION)
826 #else
827 			    "without OpenSSL"
828 #endif
829 			);
830 			if (opt == 'V')
831 				exit(0);
832 			break;
833 		case 'w':
834 			if (options.tun_open == -1)
835 				options.tun_open = SSH_TUNMODE_DEFAULT;
836 			options.tun_local = a2tun(optarg, &options.tun_remote);
837 			if (options.tun_local == SSH_TUNID_ERR) {
838 				fprintf(stderr,
839 				    "Bad tun device '%s'\n", optarg);
840 				exit(255);
841 			}
842 			break;
843 		case 'W':
844 			if (options.stdio_forward_host != NULL)
845 				fatal("stdio forward already specified");
846 			if (muxclient_command != 0)
847 				fatal("Cannot specify stdio forward with -O");
848 			if (parse_forward(&fwd, optarg, 1, 0)) {
849 				options.stdio_forward_host = fwd.listen_host;
850 				options.stdio_forward_port = fwd.listen_port;
851 				free(fwd.connect_host);
852 			} else {
853 				fprintf(stderr,
854 				    "Bad stdio forwarding specification '%s'\n",
855 				    optarg);
856 				exit(255);
857 			}
858 			options.request_tty = REQUEST_TTY_NO;
859 			no_shell_flag = 1;
860 			break;
861 		case 'q':
862 			options.log_level = SYSLOG_LEVEL_QUIET;
863 			break;
864 		case 'e':
865 			if (optarg[0] == '^' && optarg[2] == 0 &&
866 			    (u_char) optarg[1] >= 64 &&
867 			    (u_char) optarg[1] < 128)
868 				options.escape_char = (u_char) optarg[1] & 31;
869 			else if (strlen(optarg) == 1)
870 				options.escape_char = (u_char) optarg[0];
871 			else if (strcmp(optarg, "none") == 0)
872 				options.escape_char = SSH_ESCAPECHAR_NONE;
873 			else {
874 				fprintf(stderr, "Bad escape character '%s'.\n",
875 				    optarg);
876 				exit(255);
877 			}
878 			break;
879 		case 'c':
880 			if (!ciphers_valid(*optarg == '+' ?
881 			    optarg + 1 : optarg)) {
882 				fprintf(stderr, "Unknown cipher type '%s'\n",
883 				    optarg);
884 				exit(255);
885 			}
886 			free(options.ciphers);
887 			options.ciphers = xstrdup(optarg);
888 			break;
889 		case 'm':
890 			if (mac_valid(optarg)) {
891 				free(options.macs);
892 				options.macs = xstrdup(optarg);
893 			} else {
894 				fprintf(stderr, "Unknown mac type '%s'\n",
895 				    optarg);
896 				exit(255);
897 			}
898 			break;
899 		case 'M':
900 			if (options.control_master == SSHCTL_MASTER_YES)
901 				options.control_master = SSHCTL_MASTER_ASK;
902 			else
903 				options.control_master = SSHCTL_MASTER_YES;
904 			break;
905 		case 'p':
906 			if (options.port == -1) {
907 				options.port = a2port(optarg);
908 				if (options.port <= 0) {
909 					fprintf(stderr, "Bad port '%s'\n",
910 					    optarg);
911 					exit(255);
912 				}
913 			}
914 			break;
915 		case 'l':
916 			if (options.user == NULL)
917 				options.user = optarg;
918 			break;
919 
920 		case 'L':
921 			if (parse_forward(&fwd, optarg, 0, 0))
922 				add_local_forward(&options, &fwd);
923 			else {
924 				fprintf(stderr,
925 				    "Bad local forwarding specification '%s'\n",
926 				    optarg);
927 				exit(255);
928 			}
929 			break;
930 
931 		case 'R':
932 			if (parse_forward(&fwd, optarg, 0, 1) ||
933 			    parse_forward(&fwd, optarg, 1, 1)) {
934 				add_remote_forward(&options, &fwd);
935 			} else {
936 				fprintf(stderr,
937 				    "Bad remote forwarding specification "
938 				    "'%s'\n", optarg);
939 				exit(255);
940 			}
941 			break;
942 
943 		case 'D':
944 			if (parse_forward(&fwd, optarg, 1, 0)) {
945 				add_local_forward(&options, &fwd);
946 			} else {
947 				fprintf(stderr,
948 				    "Bad dynamic forwarding specification "
949 				    "'%s'\n", optarg);
950 				exit(255);
951 			}
952 			break;
953 
954 		case 'C':
955 			options.compression = 1;
956 			break;
957 		case 'N':
958 			no_shell_flag = 1;
959 			options.request_tty = REQUEST_TTY_NO;
960 			break;
961 		case 'T':
962 			options.request_tty = REQUEST_TTY_NO;
963 			break;
964 		case 'o':
965 			line = xstrdup(optarg);
966 			if (process_config_line(&options, pw,
967 			    host ? host : "", host ? host : "", line,
968 			    "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
969 				exit(255);
970 			free(line);
971 			break;
972 		case 's':
973 			subsystem_flag = 1;
974 			break;
975 		case 'S':
976 			free(options.control_path);
977 			options.control_path = xstrdup(optarg);
978 			break;
979 		case 'b':
980 			options.bind_address = optarg;
981 			break;
982 		case 'B':
983 			options.bind_interface = optarg;
984 			break;
985 		case 'F':
986 			config = optarg;
987 			break;
988 		default:
989 			usage();
990 		}
991 	}
992 
993 	if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
994 		opt_terminated = 1;
995 
996 	ac -= optind;
997 	av += optind;
998 
999 	if (ac > 0 && !host) {
1000 		int tport;
1001 		char *tuser;
1002 		switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1003 		case -1:
1004 			usage();
1005 			break;
1006 		case 0:
1007 			if (options.user == NULL) {
1008 				options.user = tuser;
1009 				tuser = NULL;
1010 			}
1011 			free(tuser);
1012 			if (options.port == -1 && tport != -1)
1013 				options.port = tport;
1014 			break;
1015 		default:
1016 			p = xstrdup(*av);
1017 			cp = strrchr(p, '@');
1018 			if (cp != NULL) {
1019 				if (cp == p)
1020 					usage();
1021 				if (options.user == NULL) {
1022 					options.user = p;
1023 					p = NULL;
1024 				}
1025 				*cp++ = '\0';
1026 				host = xstrdup(cp);
1027 				free(p);
1028 			} else
1029 				host = p;
1030 			break;
1031 		}
1032 		if (ac > 1 && !opt_terminated) {
1033 			optind = optreset = 1;
1034 			goto again;
1035 		}
1036 		ac--, av++;
1037 	}
1038 
1039 	/* Check that we got a host name. */
1040 	if (!host)
1041 		usage();
1042 
1043 	host_arg = xstrdup(host);
1044 
1045 	/* Initialize the command to execute on remote host. */
1046 	if ((command = sshbuf_new()) == NULL)
1047 		fatal("sshbuf_new failed");
1048 
1049 	/*
1050 	 * Save the command to execute on the remote host in a buffer. There
1051 	 * is no limit on the length of the command, except by the maximum
1052 	 * packet size.  Also sets the tty flag if there is no command.
1053 	 */
1054 	if (!ac) {
1055 		/* No command specified - execute shell on a tty. */
1056 		if (subsystem_flag) {
1057 			fprintf(stderr,
1058 			    "You must specify a subsystem to invoke.\n");
1059 			usage();
1060 		}
1061 	} else {
1062 		/* A command has been specified.  Store it into the buffer. */
1063 		for (i = 0; i < ac; i++) {
1064 			if ((r = sshbuf_putf(command, "%s%s",
1065 			    i ? " " : "", av[i])) != 0)
1066 				fatal("%s: buffer error: %s",
1067 				    __func__, ssh_err(r));
1068 		}
1069 	}
1070 
1071 	/*
1072 	 * Initialize "log" output.  Since we are the client all output
1073 	 * goes to stderr unless otherwise specified by -y or -E.
1074 	 */
1075 	if (use_syslog && logfile != NULL)
1076 		fatal("Can't specify both -y and -E");
1077 	if (logfile != NULL)
1078 		log_redirect_stderr_to(logfile);
1079 	log_init(argv0,
1080 	    options.log_level == SYSLOG_LEVEL_NOT_SET ?
1081 	    SYSLOG_LEVEL_INFO : options.log_level,
1082 	    options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1083 	    SYSLOG_FACILITY_USER : options.log_facility,
1084 	    !use_syslog);
1085 
1086 	if (debug_flag)
1087 		logit("%s, %s", SSH_RELEASE,
1088 #ifdef WITH_OPENSSL
1089 		    OpenSSL_version(OPENSSL_VERSION)
1090 #else
1091 		    "without OpenSSL"
1092 #endif
1093 		);
1094 
1095 	/* Parse the configuration files */
1096 	process_config_files(host_arg, pw, 0, &want_final_pass);
1097 	if (want_final_pass)
1098 		debug("configuration requests final Match pass");
1099 
1100 	/* Hostname canonicalisation needs a few options filled. */
1101 	fill_default_options_for_canonicalization(&options);
1102 
1103 	/* If the user has replaced the hostname then take it into use now */
1104 	if (options.hostname != NULL) {
1105 		/* NB. Please keep in sync with readconf.c:match_cfg_line() */
1106 		cp = percent_expand(options.hostname,
1107 		    "h", host, (char *)NULL);
1108 		free(host);
1109 		host = cp;
1110 		free(options.hostname);
1111 		options.hostname = xstrdup(host);
1112 	}
1113 
1114 	/* Don't lowercase addresses, they will be explicitly canonicalised */
1115 	if ((was_addr = is_addr(host)) == 0)
1116 		lowercase(host);
1117 
1118 	/*
1119 	 * Try to canonicalize if requested by configuration or the
1120 	 * hostname is an address.
1121 	 */
1122 	if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1123 		addrs = resolve_canonicalize(&host, options.port);
1124 
1125 	/*
1126 	 * If CanonicalizePermittedCNAMEs have been specified but
1127 	 * other canonicalization did not happen (by not being requested
1128 	 * or by failing with fallback) then the hostname may still be changed
1129 	 * as a result of CNAME following.
1130 	 *
1131 	 * Try to resolve the bare hostname name using the system resolver's
1132 	 * usual search rules and then apply the CNAME follow rules.
1133 	 *
1134 	 * Skip the lookup if a ProxyCommand is being used unless the user
1135 	 * has specifically requested canonicalisation for this case via
1136 	 * CanonicalizeHostname=always
1137 	 */
1138 	direct = option_clear_or_none(options.proxy_command) &&
1139 	    options.jump_host == NULL;
1140 	if (addrs == NULL && options.num_permitted_cnames != 0 && (direct ||
1141 	    options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1142 		if ((addrs = resolve_host(host, options.port,
1143 		    direct, cname, sizeof(cname))) == NULL) {
1144 			/* Don't fatal proxied host names not in the DNS */
1145 			if (direct)
1146 				cleanup_exit(255); /* logged in resolve_host */
1147 		} else
1148 			check_follow_cname(direct, &host, cname);
1149 	}
1150 
1151 	/*
1152 	 * If canonicalisation is enabled then re-parse the configuration
1153 	 * files as new stanzas may match.
1154 	 */
1155 	if (options.canonicalize_hostname != 0 && !want_final_pass) {
1156 		debug("hostname canonicalisation enabled, "
1157 		    "will re-parse configuration");
1158 		want_final_pass = 1;
1159 	}
1160 
1161 	if (want_final_pass) {
1162 		debug("re-parsing configuration");
1163 		free(options.hostname);
1164 		options.hostname = xstrdup(host);
1165 		process_config_files(host_arg, pw, 1, NULL);
1166 		/*
1167 		 * Address resolution happens early with canonicalisation
1168 		 * enabled and the port number may have changed since, so
1169 		 * reset it in address list
1170 		 */
1171 		if (addrs != NULL && options.port > 0)
1172 			set_addrinfo_port(addrs, options.port);
1173 	}
1174 
1175 	/* Fill configuration defaults. */
1176 	fill_default_options(&options);
1177 
1178 	/*
1179 	 * If ProxyJump option specified, then construct a ProxyCommand now.
1180 	 */
1181 	if (options.jump_host != NULL) {
1182 		char port_s[8];
1183 		const char *sshbin = argv0;
1184 
1185 		/*
1186 		 * Try to use SSH indicated by argv[0], but fall back to
1187 		 * "ssh" if it appears unavailable.
1188 		 */
1189 		if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1190 			sshbin = "ssh";
1191 
1192 		/* Consistency check */
1193 		if (options.proxy_command != NULL)
1194 			fatal("inconsistent options: ProxyCommand+ProxyJump");
1195 		/* Never use FD passing for ProxyJump */
1196 		options.proxy_use_fdpass = 0;
1197 		snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1198 		xasprintf(&options.proxy_command,
1199 		    "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1200 		    sshbin,
1201 		    /* Optional "-l user" argument if jump_user set */
1202 		    options.jump_user == NULL ? "" : " -l ",
1203 		    options.jump_user == NULL ? "" : options.jump_user,
1204 		    /* Optional "-p port" argument if jump_port set */
1205 		    options.jump_port <= 0 ? "" : " -p ",
1206 		    options.jump_port <= 0 ? "" : port_s,
1207 		    /* Optional additional jump hosts ",..." */
1208 		    options.jump_extra == NULL ? "" : " -J ",
1209 		    options.jump_extra == NULL ? "" : options.jump_extra,
1210 		    /* Optional "-F" argumment if -F specified */
1211 		    config == NULL ? "" : " -F ",
1212 		    config == NULL ? "" : config,
1213 		    /* Optional "-v" arguments if -v set */
1214 		    debug_flag ? " -" : "",
1215 		    debug_flag, "vvv",
1216 		    /* Mandatory hostname */
1217 		    options.jump_host);
1218 		debug("Setting implicit ProxyCommand from ProxyJump: %s",
1219 		    options.proxy_command);
1220 	}
1221 
1222 	if (options.port == 0)
1223 		options.port = default_ssh_port();
1224 	channel_set_af(ssh, options.address_family);
1225 
1226 	/* Tidy and check options */
1227 	if (options.host_key_alias != NULL)
1228 		lowercase(options.host_key_alias);
1229 	if (options.proxy_command != NULL &&
1230 	    strcmp(options.proxy_command, "-") == 0 &&
1231 	    options.proxy_use_fdpass)
1232 		fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1233 	if (options.control_persist &&
1234 	    options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1235 		debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1236 		    "disabling");
1237 		options.update_hostkeys = 0;
1238 	}
1239 	if (options.connection_attempts <= 0)
1240 		fatal("Invalid number of ConnectionAttempts");
1241 
1242 	if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1243 		fatal("Cannot execute command-line and remote command.");
1244 
1245 	/* Cannot fork to background if no command. */
1246 	if (fork_after_authentication_flag && sshbuf_len(command) == 0 &&
1247 	    options.remote_command == NULL && !no_shell_flag)
1248 		fatal("Cannot fork into background without a command "
1249 		    "to execute.");
1250 
1251 	/* reinit */
1252 	log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1253 
1254 	if (options.request_tty == REQUEST_TTY_YES ||
1255 	    options.request_tty == REQUEST_TTY_FORCE)
1256 		tty_flag = 1;
1257 
1258 	/* Allocate a tty by default if no command specified. */
1259 	if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1260 		tty_flag = options.request_tty != REQUEST_TTY_NO;
1261 
1262 	/* Force no tty */
1263 	if (options.request_tty == REQUEST_TTY_NO ||
1264 	    (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1265 		tty_flag = 0;
1266 	/* Do not allocate a tty if stdin is not a tty. */
1267 	if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1268 	    options.request_tty != REQUEST_TTY_FORCE) {
1269 		if (tty_flag)
1270 			logit("Pseudo-terminal will not be allocated because "
1271 			    "stdin is not a terminal.");
1272 		tty_flag = 0;
1273 	}
1274 
1275 	if (options.user == NULL)
1276 		options.user = xstrdup(pw->pw_name);
1277 
1278 	/* Set up strings used to percent_expand() arguments */
1279 	if (gethostname(thishost, sizeof(thishost)) == -1)
1280 		fatal("gethostname: %s", strerror(errno));
1281 	strlcpy(shorthost, thishost, sizeof(shorthost));
1282 	shorthost[strcspn(thishost, ".")] = '\0';
1283 	snprintf(portstr, sizeof(portstr), "%d", options.port);
1284 	snprintf(uidstr, sizeof(uidstr), "%llu",
1285 	    (unsigned long long)pw->pw_uid);
1286 
1287 	if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1288 	    ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1289 	    ssh_digest_update(md, host, strlen(host)) < 0 ||
1290 	    ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1291 	    ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1292 	    ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1293 		fatal("%s: mux digest failed", __func__);
1294 	ssh_digest_free(md);
1295 	conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1296 
1297 	/*
1298 	 * Expand tokens in arguments. NB. LocalCommand is expanded later,
1299 	 * after port-forwarding is set up, so it may pick up any local
1300 	 * tunnel interface name allocated.
1301 	 */
1302 	if (options.remote_command != NULL) {
1303 		debug3("expanding RemoteCommand: %s", options.remote_command);
1304 		cp = options.remote_command;
1305 		options.remote_command = percent_expand(cp,
1306 		    "C", conn_hash_hex,
1307 		    "L", shorthost,
1308 		    "d", pw->pw_dir,
1309 		    "h", host,
1310 		    "i", uidstr,
1311 		    "l", thishost,
1312 		    "n", host_arg,
1313 		    "p", portstr,
1314 		    "r", options.user,
1315 		    "u", pw->pw_name,
1316 		    (char *)NULL);
1317 		debug3("expanded RemoteCommand: %s", options.remote_command);
1318 		free(cp);
1319 		if ((r = sshbuf_put(command, options.remote_command,
1320 		    strlen(options.remote_command))) != 0)
1321 			fatal("%s: buffer error: %s", __func__, ssh_err(r));
1322 	}
1323 
1324 	if (options.control_path != NULL) {
1325 		cp = tilde_expand_filename(options.control_path, getuid());
1326 		free(options.control_path);
1327 		options.control_path = percent_expand(cp,
1328 		    "C", conn_hash_hex,
1329 		    "L", shorthost,
1330 		    "h", host,
1331 		    "i", uidstr,
1332 		    "l", thishost,
1333 		    "n", host_arg,
1334 		    "p", portstr,
1335 		    "r", options.user,
1336 		    "u", pw->pw_name,
1337 		    "i", uidstr,
1338 		    (char *)NULL);
1339 		free(cp);
1340 	}
1341 
1342 	if (config_test) {
1343 		dump_client_config(&options, host);
1344 		exit(0);
1345 	}
1346 
1347 	if (muxclient_command != 0 && options.control_path == NULL)
1348 		fatal("No ControlPath specified for \"-O\" command");
1349 	if (options.control_path != NULL) {
1350 		int sock;
1351 		if ((sock = muxclient(options.control_path)) >= 0) {
1352 			ssh_packet_set_connection(ssh, sock, sock);
1353 			ssh_packet_set_mux(ssh);
1354 			goto skip_connect;
1355 		}
1356 	}
1357 
1358 	/*
1359 	 * If hostname canonicalisation was not enabled, then we may not
1360 	 * have yet resolved the hostname. Do so now.
1361 	 */
1362 	if (addrs == NULL && options.proxy_command == NULL) {
1363 		debug2("resolving \"%s\" port %d", host, options.port);
1364 		if ((addrs = resolve_host(host, options.port, 1,
1365 		    cname, sizeof(cname))) == NULL)
1366 			cleanup_exit(255); /* resolve_host logs the error */
1367 	}
1368 
1369 	timeout_ms = options.connection_timeout * 1000;
1370 
1371 	/* Open a connection to the remote host. */
1372 	if (ssh_connect(ssh, host, addrs, &hostaddr, options.port,
1373 	    options.address_family, options.connection_attempts,
1374 	    &timeout_ms, options.tcp_keep_alive) != 0)
1375  		exit(255);
1376 
1377 	if (addrs != NULL)
1378 		freeaddrinfo(addrs);
1379 
1380 	ssh_packet_set_timeout(ssh, options.server_alive_interval,
1381 	    options.server_alive_count_max);
1382 
1383 	if (timeout_ms > 0)
1384 		debug3("timeout: %d ms remain after connect", timeout_ms);
1385 
1386 	/*
1387 	 * If we successfully made the connection and we have hostbased auth
1388 	 * enabled, load the public keys so we can later use the ssh-keysign
1389 	 * helper to sign challenges.
1390 	 */
1391 	sensitive_data.nkeys = 0;
1392 	sensitive_data.keys = NULL;
1393 	if (options.hostbased_authentication) {
1394 		sensitive_data.nkeys = 10;
1395 		sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1396 		    sizeof(struct sshkey));
1397 
1398 		/* XXX check errors? */
1399 #define L_PUBKEY(p,o) do { \
1400 	if ((o) >= sensitive_data.nkeys) \
1401 		fatal("%s pubkey out of array bounds", __func__); \
1402 	check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1403 	    p, "pubkey"); \
1404 } while (0)
1405 #define L_CERT(p,o) do { \
1406 	if ((o) >= sensitive_data.nkeys) \
1407 		fatal("%s cert out of array bounds", __func__); \
1408 	check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1409 } while (0)
1410 
1411 		if (options.hostbased_authentication == 1) {
1412 			L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1413 			L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1414 			L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1415 			L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1416 			L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1417 			L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1418 			L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1419 			L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1420 			L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1421 			L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1422 		}
1423 	}
1424 
1425 	/* Create ~/.ssh * directory if it doesn't already exist. */
1426 	if (config == NULL) {
1427 		r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1428 		    strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1429 		if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) == -1) {
1430 #ifdef WITH_SELINUX
1431 			ssh_selinux_setfscreatecon(buf);
1432 #endif
1433 			if (mkdir(buf, 0700) < 0)
1434 				error("Could not create directory '%.200s'.",
1435 				    buf);
1436 #ifdef WITH_SELINUX
1437 			ssh_selinux_setfscreatecon(NULL);
1438 #endif
1439 		}
1440 	}
1441 	/* load options.identity_files */
1442 	load_public_identity_files(pw);
1443 
1444 	/* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1445 	if (options.identity_agent &&
1446 	    strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1447 		if (strcmp(options.identity_agent, "none") == 0) {
1448 			unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1449 		} else {
1450 			p = tilde_expand_filename(options.identity_agent,
1451 			    getuid());
1452 			cp = percent_expand(p,
1453 			    "d", pw->pw_dir,
1454 			    "h", host,
1455 			    "i", uidstr,
1456 			    "l", thishost,
1457 			    "r", options.user,
1458 			    "u", pw->pw_name,
1459 			    (char *)NULL);
1460 			free(p);
1461 			/*
1462 			 * If identity_agent represents an environment variable
1463 			 * then recheck that it is valid (since processing with
1464 			 * percent_expand() may have changed it) and substitute
1465 			 * its value.
1466 			 */
1467 			if (cp[0] == '$') {
1468 				if (!valid_env_name(cp + 1)) {
1469 					fatal("Invalid IdentityAgent "
1470 					    "environment variable name %s", cp);
1471 				}
1472 				if ((p = getenv(cp + 1)) == NULL)
1473 					unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1474 				else
1475 					setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1476 			} else {
1477 				/* identity_agent specifies a path directly */
1478 				setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1479 			}
1480 			free(cp);
1481 		}
1482 	}
1483 
1484 	/* Expand ~ in known host file names. */
1485 	tilde_expand_paths(options.system_hostfiles,
1486 	    options.num_system_hostfiles);
1487 	tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1488 
1489 	signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1490 	signal(SIGCHLD, main_sigchld_handler);
1491 
1492 	/* Log into the remote system.  Never returns if the login fails. */
1493 	ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1494 	    options.port, pw, timeout_ms);
1495 
1496 	if (ssh_packet_connection_is_on_socket(ssh)) {
1497 		verbose("Authenticated to %s ([%s]:%d).", host,
1498 		    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1499 	} else {
1500 		verbose("Authenticated to %s (via proxy).", host);
1501 	}
1502 
1503 	/* We no longer need the private host keys.  Clear them now. */
1504 	if (sensitive_data.nkeys != 0) {
1505 		for (i = 0; i < sensitive_data.nkeys; i++) {
1506 			if (sensitive_data.keys[i] != NULL) {
1507 				/* Destroys contents safely */
1508 				debug3("clear hostkey %d", i);
1509 				sshkey_free(sensitive_data.keys[i]);
1510 				sensitive_data.keys[i] = NULL;
1511 			}
1512 		}
1513 		free(sensitive_data.keys);
1514 	}
1515 	for (i = 0; i < options.num_identity_files; i++) {
1516 		free(options.identity_files[i]);
1517 		options.identity_files[i] = NULL;
1518 		if (options.identity_keys[i]) {
1519 			sshkey_free(options.identity_keys[i]);
1520 			options.identity_keys[i] = NULL;
1521 		}
1522 	}
1523 	for (i = 0; i < options.num_certificate_files; i++) {
1524 		free(options.certificate_files[i]);
1525 		options.certificate_files[i] = NULL;
1526 	}
1527 
1528  skip_connect:
1529 	exit_status = ssh_session2(ssh, pw);
1530 	ssh_packet_close(ssh);
1531 
1532 	if (options.control_path != NULL && muxserver_sock != -1)
1533 		unlink(options.control_path);
1534 
1535 	/* Kill ProxyCommand if it is running. */
1536 	ssh_kill_proxy_command();
1537 
1538 	return exit_status;
1539 }
1540 
1541 static void
control_persist_detach(void)1542 control_persist_detach(void)
1543 {
1544 	pid_t pid;
1545 	int devnull, keep_stderr;
1546 
1547 	debug("%s: backgrounding master process", __func__);
1548 
1549 	/*
1550 	 * master (current process) into the background, and make the
1551 	 * foreground process a client of the backgrounded master.
1552 	 */
1553 	switch ((pid = fork())) {
1554 	case -1:
1555 		fatal("%s: fork: %s", __func__, strerror(errno));
1556 	case 0:
1557 		/* Child: master process continues mainloop */
1558 		break;
1559 	default:
1560 		/* Parent: set up mux slave to connect to backgrounded master */
1561 		debug2("%s: background process is %ld", __func__, (long)pid);
1562 		stdin_null_flag = ostdin_null_flag;
1563 		options.request_tty = orequest_tty;
1564 		tty_flag = otty_flag;
1565 		close(muxserver_sock);
1566 		muxserver_sock = -1;
1567 		options.control_master = SSHCTL_MASTER_NO;
1568 		muxclient(options.control_path);
1569 		/* muxclient() doesn't return on success. */
1570 		fatal("Failed to connect to new control master");
1571 	}
1572 	if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1573 		error("%s: open(\"/dev/null\"): %s", __func__,
1574 		    strerror(errno));
1575 	} else {
1576 		keep_stderr = log_is_on_stderr() && debug_flag;
1577 		if (dup2(devnull, STDIN_FILENO) == -1 ||
1578 		    dup2(devnull, STDOUT_FILENO) == -1 ||
1579 		    (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
1580 			error("%s: dup2: %s", __func__, strerror(errno));
1581 		if (devnull > STDERR_FILENO)
1582 			close(devnull);
1583 	}
1584 	daemon(1, 1);
1585 	setproctitle("%s [mux]", options.control_path);
1586 }
1587 
1588 /* Do fork() after authentication. Used by "ssh -f" */
1589 static void
fork_postauth(void)1590 fork_postauth(void)
1591 {
1592 	if (need_controlpersist_detach)
1593 		control_persist_detach();
1594 	debug("forking to background");
1595 	fork_after_authentication_flag = 0;
1596 	if (daemon(1, 1) == -1)
1597 		fatal("daemon() failed: %.200s", strerror(errno));
1598 }
1599 
1600 /* Callback for remote forward global requests */
1601 static void
ssh_confirm_remote_forward(struct ssh * ssh,int type,u_int32_t seq,void * ctxt)1602 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1603 {
1604 	struct Forward *rfwd = (struct Forward *)ctxt;
1605 	u_int port;
1606 	int r;
1607 
1608 	/* XXX verbose() on failure? */
1609 	debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1610 	    type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1611 	    rfwd->listen_path ? rfwd->listen_path :
1612 	    rfwd->listen_host ? rfwd->listen_host : "",
1613 	    (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1614 	    rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1615 	    rfwd->connect_host, rfwd->connect_port);
1616 	if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1617 		if (type == SSH2_MSG_REQUEST_SUCCESS) {
1618 			if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1619 				fatal("%s: %s", __func__, ssh_err(r));
1620 			if (port > 65535) {
1621 				error("Invalid allocated port %u for remote "
1622 				    "forward to %s:%d", port,
1623 				    rfwd->connect_host, rfwd->connect_port);
1624 				/* Ensure failure processing runs below */
1625 				type = SSH2_MSG_REQUEST_FAILURE;
1626 				channel_update_permission(ssh,
1627 				    rfwd->handle, -1);
1628 			} else {
1629 				rfwd->allocated_port = (int)port;
1630 				logit("Allocated port %u for remote "
1631 				    "forward to %s:%d",
1632 				    rfwd->allocated_port, rfwd->connect_host,
1633 				    rfwd->connect_port);
1634 				channel_update_permission(ssh,
1635 				    rfwd->handle, rfwd->allocated_port);
1636 			}
1637 		} else {
1638 			channel_update_permission(ssh, rfwd->handle, -1);
1639 		}
1640 	}
1641 
1642 	if (type == SSH2_MSG_REQUEST_FAILURE) {
1643 		if (options.exit_on_forward_failure) {
1644 			if (rfwd->listen_path != NULL)
1645 				fatal("Error: remote port forwarding failed "
1646 				    "for listen path %s", rfwd->listen_path);
1647 			else
1648 				fatal("Error: remote port forwarding failed "
1649 				    "for listen port %d", rfwd->listen_port);
1650 		} else {
1651 			if (rfwd->listen_path != NULL)
1652 				logit("Warning: remote port forwarding failed "
1653 				    "for listen path %s", rfwd->listen_path);
1654 			else
1655 				logit("Warning: remote port forwarding failed "
1656 				    "for listen port %d", rfwd->listen_port);
1657 		}
1658 	}
1659 	if (++remote_forward_confirms_received == options.num_remote_forwards) {
1660 		debug("All remote forwarding requests processed");
1661 		if (fork_after_authentication_flag)
1662 			fork_postauth();
1663 	}
1664 }
1665 
1666 static void
client_cleanup_stdio_fwd(struct ssh * ssh,int id,void * arg)1667 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1668 {
1669 	debug("stdio forwarding: done");
1670 	cleanup_exit(0);
1671 }
1672 
1673 static void
ssh_stdio_confirm(struct ssh * ssh,int id,int success,void * arg)1674 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1675 {
1676 	if (!success)
1677 		fatal("stdio forwarding failed");
1678 }
1679 
1680 static void
ssh_init_stdio_forwarding(struct ssh * ssh)1681 ssh_init_stdio_forwarding(struct ssh *ssh)
1682 {
1683 	Channel *c;
1684 	int in, out;
1685 
1686 	if (options.stdio_forward_host == NULL)
1687 		return;
1688 
1689 	debug3("%s: %s:%d", __func__, options.stdio_forward_host,
1690 	    options.stdio_forward_port);
1691 
1692 	if ((in = dup(STDIN_FILENO)) == -1 ||
1693 	    (out = dup(STDOUT_FILENO)) == -1)
1694 		fatal("channel_connect_stdio_fwd: dup() in/out failed");
1695 	if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1696 	    options.stdio_forward_port, in, out)) == NULL)
1697 		fatal("%s: channel_connect_stdio_fwd failed", __func__);
1698 	channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1699 	channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1700 }
1701 
1702 static void
ssh_init_forwarding(struct ssh * ssh,char ** ifname)1703 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1704 {
1705 	int success = 0;
1706 	int i;
1707 
1708 	/* Initiate local TCP/IP port forwardings. */
1709 	for (i = 0; i < options.num_local_forwards; i++) {
1710 		debug("Local connections to %.200s:%d forwarded to remote "
1711 		    "address %.200s:%d",
1712 		    (options.local_forwards[i].listen_path != NULL) ?
1713 		    options.local_forwards[i].listen_path :
1714 		    (options.local_forwards[i].listen_host == NULL) ?
1715 		    (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1716 		    options.local_forwards[i].listen_host,
1717 		    options.local_forwards[i].listen_port,
1718 		    (options.local_forwards[i].connect_path != NULL) ?
1719 		    options.local_forwards[i].connect_path :
1720 		    options.local_forwards[i].connect_host,
1721 		    options.local_forwards[i].connect_port);
1722 		success += channel_setup_local_fwd_listener(ssh,
1723 		    &options.local_forwards[i], &options.fwd_opts);
1724 	}
1725 	if (i > 0 && success != i && options.exit_on_forward_failure)
1726 		fatal("Could not request local forwarding.");
1727 	if (i > 0 && success == 0)
1728 		error("Could not request local forwarding.");
1729 
1730 	/* Initiate remote TCP/IP port forwardings. */
1731 	for (i = 0; i < options.num_remote_forwards; i++) {
1732 		debug("Remote connections from %.200s:%d forwarded to "
1733 		    "local address %.200s:%d",
1734 		    (options.remote_forwards[i].listen_path != NULL) ?
1735 		    options.remote_forwards[i].listen_path :
1736 		    (options.remote_forwards[i].listen_host == NULL) ?
1737 		    "LOCALHOST" : options.remote_forwards[i].listen_host,
1738 		    options.remote_forwards[i].listen_port,
1739 		    (options.remote_forwards[i].connect_path != NULL) ?
1740 		    options.remote_forwards[i].connect_path :
1741 		    options.remote_forwards[i].connect_host,
1742 		    options.remote_forwards[i].connect_port);
1743 		options.remote_forwards[i].handle =
1744 		    channel_request_remote_forwarding(ssh,
1745 		    &options.remote_forwards[i]);
1746 		if (options.remote_forwards[i].handle < 0) {
1747 			if (options.exit_on_forward_failure)
1748 				fatal("Could not request remote forwarding.");
1749 			else
1750 				logit("Warning: Could not request remote "
1751 				    "forwarding.");
1752 		} else {
1753 			client_register_global_confirm(
1754 			    ssh_confirm_remote_forward,
1755 			    &options.remote_forwards[i]);
1756 		}
1757 	}
1758 
1759 	/* Initiate tunnel forwarding. */
1760 	if (options.tun_open != SSH_TUNMODE_NO) {
1761 		if ((*ifname = client_request_tun_fwd(ssh,
1762 		    options.tun_open, options.tun_local,
1763 		    options.tun_remote)) == NULL) {
1764 			if (options.exit_on_forward_failure)
1765 				fatal("Could not request tunnel forwarding.");
1766 			else
1767 				error("Could not request tunnel forwarding.");
1768 		}
1769 	}
1770 }
1771 
1772 static void
check_agent_present(void)1773 check_agent_present(void)
1774 {
1775 	int r;
1776 
1777 	if (options.forward_agent) {
1778 		/* Clear agent forwarding if we don't have an agent. */
1779 		if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1780 			options.forward_agent = 0;
1781 			if (r != SSH_ERR_AGENT_NOT_PRESENT)
1782 				debug("ssh_get_authentication_socket: %s",
1783 				    ssh_err(r));
1784 		}
1785 	}
1786 }
1787 
1788 static void
ssh_session2_setup(struct ssh * ssh,int id,int success,void * arg)1789 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
1790 {
1791 	extern char **environ;
1792 	const char *display;
1793 	int r, interactive = tty_flag;
1794 	char *proto = NULL, *data = NULL;
1795 
1796 	if (!success)
1797 		return; /* No need for error message, channels code sens one */
1798 
1799 	display = getenv("DISPLAY");
1800 	if (display == NULL && options.forward_x11)
1801 		debug("X11 forwarding requested but DISPLAY not set");
1802 	if (options.forward_x11 && client_x11_get_proto(ssh, display,
1803 	    options.xauth_location, options.forward_x11_trusted,
1804 	    options.forward_x11_timeout, &proto, &data) == 0) {
1805 		/* Request forwarding with authentication spoofing. */
1806 		debug("Requesting X11 forwarding with authentication "
1807 		    "spoofing.");
1808 		x11_request_forwarding_with_spoofing(ssh, id, display, proto,
1809 		    data, 1);
1810 		client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
1811 		/* XXX exit_on_forward_failure */
1812 		interactive = 1;
1813 	}
1814 
1815 	check_agent_present();
1816 	if (options.forward_agent) {
1817 		debug("Requesting authentication agent forwarding.");
1818 		channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
1819 		if ((r = sshpkt_send(ssh)) != 0)
1820 			fatal("%s: %s", __func__, ssh_err(r));
1821 	}
1822 
1823 	/* Tell the packet module whether this is an interactive session. */
1824 	ssh_packet_set_interactive(ssh, interactive,
1825 	    options.ip_qos_interactive, options.ip_qos_bulk);
1826 
1827 	client_session2_setup(ssh, id, tty_flag, subsystem_flag, getenv("TERM"),
1828 	    NULL, fileno(stdin), command, environ);
1829 }
1830 
1831 /* open new channel for a session */
1832 static int
ssh_session2_open(struct ssh * ssh)1833 ssh_session2_open(struct ssh *ssh)
1834 {
1835 	Channel *c;
1836 	int window, packetmax, in, out, err;
1837 
1838 	if (stdin_null_flag) {
1839 		in = open(_PATH_DEVNULL, O_RDONLY);
1840 	} else {
1841 		in = dup(STDIN_FILENO);
1842 	}
1843 	out = dup(STDOUT_FILENO);
1844 	err = dup(STDERR_FILENO);
1845 
1846 	if (in == -1 || out == -1 || err == -1)
1847 		fatal("dup() in/out/err failed");
1848 
1849 	/* enable nonblocking unless tty */
1850 	if (!isatty(in))
1851 		set_nonblock(in);
1852 	if (!isatty(out))
1853 		set_nonblock(out);
1854 	if (!isatty(err))
1855 		set_nonblock(err);
1856 
1857 	window = CHAN_SES_WINDOW_DEFAULT;
1858 	packetmax = CHAN_SES_PACKET_DEFAULT;
1859 	if (tty_flag) {
1860 		window >>= 1;
1861 		packetmax >>= 1;
1862 	}
1863 	c = channel_new(ssh,
1864 	    "session", SSH_CHANNEL_OPENING, in, out, err,
1865 	    window, packetmax, CHAN_EXTENDED_WRITE,
1866 	    "client-session", /*nonblock*/0);
1867 
1868 	debug3("%s: channel_new: %d", __func__, c->self);
1869 
1870 	channel_send_open(ssh, c->self);
1871 	if (!no_shell_flag)
1872 		channel_register_open_confirm(ssh, c->self,
1873 		    ssh_session2_setup, NULL);
1874 
1875 	return c->self;
1876 }
1877 
1878 static int
ssh_session2(struct ssh * ssh,struct passwd * pw)1879 ssh_session2(struct ssh *ssh, struct passwd *pw)
1880 {
1881 	int r, devnull, id = -1;
1882 	char *cp, *tun_fwd_ifname = NULL;
1883 
1884 	/* XXX should be pre-session */
1885 	if (!options.control_persist)
1886 		ssh_init_stdio_forwarding(ssh);
1887 
1888 	ssh_init_forwarding(ssh, &tun_fwd_ifname);
1889 
1890 	if (options.local_command != NULL) {
1891 		debug3("expanding LocalCommand: %s", options.local_command);
1892 		cp = options.local_command;
1893 		options.local_command = percent_expand(cp,
1894 		    "C", conn_hash_hex,
1895 		    "L", shorthost,
1896 		    "d", pw->pw_dir,
1897 		    "h", host,
1898 		    "i", uidstr,
1899 		    "l", thishost,
1900 		    "n", host_arg,
1901 		    "p", portstr,
1902 		    "r", options.user,
1903 		    "u", pw->pw_name,
1904 		    "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
1905 		    (char *)NULL);
1906 		debug3("expanded LocalCommand: %s", options.local_command);
1907 		free(cp);
1908 	}
1909 
1910 	/* Start listening for multiplex clients */
1911 	if (!ssh_packet_get_mux(ssh))
1912 		muxserver_listen(ssh);
1913 
1914 	/*
1915 	 * If we are in control persist mode and have a working mux listen
1916 	 * socket, then prepare to background ourselves and have a foreground
1917 	 * client attach as a control slave.
1918 	 * NB. we must save copies of the flags that we override for
1919 	 * the backgrounding, since we defer attachment of the slave until
1920 	 * after the connection is fully established (in particular,
1921 	 * async rfwd replies have been received for ExitOnForwardFailure).
1922 	 */
1923 	if (options.control_persist && muxserver_sock != -1) {
1924 		ostdin_null_flag = stdin_null_flag;
1925 		ono_shell_flag = no_shell_flag;
1926 		orequest_tty = options.request_tty;
1927 		otty_flag = tty_flag;
1928 		stdin_null_flag = 1;
1929 		no_shell_flag = 1;
1930 		tty_flag = 0;
1931 		if (!fork_after_authentication_flag)
1932 			need_controlpersist_detach = 1;
1933 		fork_after_authentication_flag = 1;
1934 	}
1935 	/*
1936 	 * ControlPersist mux listen socket setup failed, attempt the
1937 	 * stdio forward setup that we skipped earlier.
1938 	 */
1939 	if (options.control_persist && muxserver_sock == -1)
1940 		ssh_init_stdio_forwarding(ssh);
1941 
1942 	if (!no_shell_flag)
1943 		id = ssh_session2_open(ssh);
1944 	else {
1945 		ssh_packet_set_interactive(ssh,
1946 		    options.control_master == SSHCTL_MASTER_NO,
1947 		    options.ip_qos_interactive, options.ip_qos_bulk);
1948 	}
1949 
1950 	/* If we don't expect to open a new session, then disallow it */
1951 	if (options.control_master == SSHCTL_MASTER_NO &&
1952 	    (datafellows & SSH_NEW_OPENSSH)) {
1953 		debug("Requesting no-more-sessions@openssh.com");
1954 		if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
1955 		    (r = sshpkt_put_cstring(ssh,
1956 		    "no-more-sessions@openssh.com")) != 0 ||
1957 		    (r = sshpkt_put_u8(ssh, 0)) != 0 ||
1958 		    (r = sshpkt_send(ssh)) != 0)
1959 			fatal("%s: %s", __func__, ssh_err(r));
1960 	}
1961 
1962 	/* Execute a local command */
1963 	if (options.local_command != NULL &&
1964 	    options.permit_local_command)
1965 		ssh_local_cmd(options.local_command);
1966 
1967 	/*
1968 	 * stdout is now owned by the session channel; clobber it here
1969 	 * so future channel closes are propagated to the local fd.
1970 	 * NB. this can only happen after LocalCommand has completed,
1971 	 * as it may want to write to stdout.
1972 	 */
1973 	if (!need_controlpersist_detach) {
1974 		if ((devnull = open(_PATH_DEVNULL, O_WRONLY)) == -1)
1975 			error("%s: open %s: %s", __func__,
1976 			    _PATH_DEVNULL, strerror(errno));
1977 		if (dup2(devnull, STDOUT_FILENO) == -1)
1978 			fatal("%s: dup2() stdout failed", __func__);
1979 		if (devnull > STDERR_FILENO)
1980 			close(devnull);
1981 	}
1982 
1983 	/*
1984 	 * If requested and we are not interested in replies to remote
1985 	 * forwarding requests, then let ssh continue in the background.
1986 	 */
1987 	if (fork_after_authentication_flag) {
1988 		if (options.exit_on_forward_failure &&
1989 		    options.num_remote_forwards > 0) {
1990 			debug("deferring postauth fork until remote forward "
1991 			    "confirmation received");
1992 		} else
1993 			fork_postauth();
1994 	}
1995 
1996 	return client_loop(ssh, tty_flag, tty_flag ?
1997 	    options.escape_char : SSH_ESCAPECHAR_NONE, id);
1998 }
1999 
2000 /* Loads all IdentityFile and CertificateFile keys */
2001 static void
load_public_identity_files(struct passwd * pw)2002 load_public_identity_files(struct passwd *pw)
2003 {
2004 	char *filename, *cp;
2005 	struct sshkey *public;
2006 	int i;
2007 	u_int n_ids, n_certs;
2008 	char *identity_files[SSH_MAX_IDENTITY_FILES];
2009 	struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2010 	int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2011 	char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2012 	struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2013 	int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2014 #ifdef ENABLE_PKCS11
2015 	struct sshkey **keys;
2016 	int nkeys;
2017 #endif /* PKCS11 */
2018 
2019 	n_ids = n_certs = 0;
2020 	memset(identity_files, 0, sizeof(identity_files));
2021 	memset(identity_keys, 0, sizeof(identity_keys));
2022 	memset(identity_file_userprovided, 0,
2023 	    sizeof(identity_file_userprovided));
2024 	memset(certificate_files, 0, sizeof(certificate_files));
2025 	memset(certificates, 0, sizeof(certificates));
2026 	memset(certificate_file_userprovided, 0,
2027 	    sizeof(certificate_file_userprovided));
2028 
2029 #ifdef ENABLE_PKCS11
2030 	if (options.pkcs11_provider != NULL &&
2031 	    options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2032 	    (pkcs11_init(!options.batch_mode) == 0) &&
2033 	    (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2034 	    &keys)) > 0) {
2035 		for (i = 0; i < nkeys; i++) {
2036 			if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2037 				sshkey_free(keys[i]);
2038 				continue;
2039 			}
2040 			identity_keys[n_ids] = keys[i];
2041 			identity_files[n_ids] =
2042 			    xstrdup(options.pkcs11_provider); /* XXX */
2043 			n_ids++;
2044 		}
2045 		free(keys);
2046 	}
2047 #endif /* ENABLE_PKCS11 */
2048 	for (i = 0; i < options.num_identity_files; i++) {
2049 		if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2050 		    strcasecmp(options.identity_files[i], "none") == 0) {
2051 			free(options.identity_files[i]);
2052 			options.identity_files[i] = NULL;
2053 			continue;
2054 		}
2055 		cp = tilde_expand_filename(options.identity_files[i], getuid());
2056 		filename = percent_expand(cp, "d", pw->pw_dir,
2057 		    "u", pw->pw_name, "l", thishost, "h", host,
2058 		    "r", options.user, (char *)NULL);
2059 		free(cp);
2060 		check_load(sshkey_load_public(filename, &public, NULL),
2061 		    filename, "pubkey");
2062 		debug("identity file %s type %d", filename,
2063 		    public ? public->type : -1);
2064 		free(options.identity_files[i]);
2065 		identity_files[n_ids] = filename;
2066 		identity_keys[n_ids] = public;
2067 		identity_file_userprovided[n_ids] =
2068 		    options.identity_file_userprovided[i];
2069 		if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2070 			continue;
2071 
2072 		/*
2073 		 * If no certificates have been explicitly listed then try
2074 		 * to add the default certificate variant too.
2075 		 */
2076 		if (options.num_certificate_files != 0)
2077 			continue;
2078 		xasprintf(&cp, "%s-cert", filename);
2079 		check_load(sshkey_load_public(cp, &public, NULL),
2080 		    filename, "pubkey");
2081 		debug("identity file %s type %d", cp,
2082 		    public ? public->type : -1);
2083 		if (public == NULL) {
2084 			free(cp);
2085 			continue;
2086 		}
2087 		if (!sshkey_is_cert(public)) {
2088 			debug("%s: key %s type %s is not a certificate",
2089 			    __func__, cp, sshkey_type(public));
2090 			sshkey_free(public);
2091 			free(cp);
2092 			continue;
2093 		}
2094 		/* NB. leave filename pointing to private key */
2095 		identity_files[n_ids] = xstrdup(filename);
2096 		identity_keys[n_ids] = public;
2097 		identity_file_userprovided[n_ids] =
2098 		    options.identity_file_userprovided[i];
2099 		n_ids++;
2100 	}
2101 
2102 	if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2103 		fatal("%s: too many certificates", __func__);
2104 	for (i = 0; i < options.num_certificate_files; i++) {
2105 		cp = tilde_expand_filename(options.certificate_files[i],
2106 		    getuid());
2107 		filename = percent_expand(cp,
2108 		    "d", pw->pw_dir,
2109 		    "h", host,
2110 		    "i", uidstr,
2111 		    "l", thishost,
2112 		    "r", options.user,
2113 		    "u", pw->pw_name,
2114 		    (char *)NULL);
2115 		free(cp);
2116 
2117 		check_load(sshkey_load_public(filename, &public, NULL),
2118 		    filename, "certificate");
2119 		debug("certificate file %s type %d", filename,
2120 		    public ? public->type : -1);
2121 		free(options.certificate_files[i]);
2122 		options.certificate_files[i] = NULL;
2123 		if (public == NULL) {
2124 			free(filename);
2125 			continue;
2126 		}
2127 		if (!sshkey_is_cert(public)) {
2128 			debug("%s: key %s type %s is not a certificate",
2129 			    __func__, filename, sshkey_type(public));
2130 			sshkey_free(public);
2131 			free(filename);
2132 			continue;
2133 		}
2134 		certificate_files[n_certs] = filename;
2135 		certificates[n_certs] = public;
2136 		certificate_file_userprovided[n_certs] =
2137 		    options.certificate_file_userprovided[i];
2138 		++n_certs;
2139 	}
2140 
2141 	options.num_identity_files = n_ids;
2142 	memcpy(options.identity_files, identity_files, sizeof(identity_files));
2143 	memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2144 	memcpy(options.identity_file_userprovided,
2145 	    identity_file_userprovided, sizeof(identity_file_userprovided));
2146 
2147 	options.num_certificate_files = n_certs;
2148 	memcpy(options.certificate_files,
2149 	    certificate_files, sizeof(certificate_files));
2150 	memcpy(options.certificates, certificates, sizeof(certificates));
2151 	memcpy(options.certificate_file_userprovided,
2152 	    certificate_file_userprovided,
2153 	    sizeof(certificate_file_userprovided));
2154 }
2155 
2156 static void
main_sigchld_handler(int sig)2157 main_sigchld_handler(int sig)
2158 {
2159 	int save_errno = errno;
2160 	pid_t pid;
2161 	int status;
2162 
2163 	while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2164 	    (pid == -1 && errno == EINTR))
2165 		;
2166 	errno = save_errno;
2167 }
2168