1 /* $OpenBSD: ssh.c,v 1.600 2024/01/11 01:45:36 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 "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 <stdarg.h>
69 #include <unistd.h>
70 #include <limits.h>
71 #include <locale.h>
72
73 #include <netinet/in.h>
74 #include <arpa/inet.h>
75
76 #ifdef WITH_OPENSSL
77 #include <openssl/evp.h>
78 #include <openssl/err.h>
79 #endif
80 #include "openbsd-compat/openssl-compat.h"
81 #include "openbsd-compat/sys-queue.h"
82
83 #include "xmalloc.h"
84 #include "ssh.h"
85 #include "ssh2.h"
86 #include "canohost.h"
87 #include "compat.h"
88 #include "cipher.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 /*
130 * Flag indicating that the current process should be backgrounded and
131 * a new mux-client launched in the foreground for ControlPersist.
132 */
133 static int need_controlpersist_detach = 0;
134
135 /* Copies of flags for ControlPersist foreground mux-client */
136 static int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
137 static int ofork_after_authentication;
138
139 /*
140 * General data structure for command line options and options configurable
141 * in configuration files. See readconf.h.
142 */
143 Options options;
144
145 /* optional user configfile */
146 char *config = NULL;
147
148 /*
149 * Name of the host we are connecting to. This is the name given on the
150 * command line, or the Hostname specified for the user-supplied name in a
151 * configuration file.
152 */
153 char *host;
154
155 /*
156 * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
157 * not NULL, forward the socket at this path instead.
158 */
159 char *forward_agent_sock_path = NULL;
160
161 /* socket address the host resolves to */
162 struct sockaddr_storage hostaddr;
163
164 /* Private host keys. */
165 Sensitive sensitive_data;
166
167 /* command to be executed */
168 struct sshbuf *command;
169
170 /* # of replies received for global requests */
171 static int forward_confirms_pending = -1;
172
173 /* mux.c */
174 extern int muxserver_sock;
175 extern u_int muxclient_command;
176
177 /* Prints a help message to the user. This function never returns. */
178
179 static void
usage(void)180 usage(void)
181 {
182 fprintf(stderr,
183 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface] [-b bind_address]\n"
184 " [-c cipher_spec] [-D [bind_address:]port] [-E log_file]\n"
185 " [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file]\n"
186 " [-J destination] [-L address] [-l login_name] [-m mac_spec]\n"
187 " [-O ctl_cmd] [-o option] [-P tag] [-p port] [-R address]\n"
188 " [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]\n"
189 " destination [command [argument ...]]\n"
190 " ssh [-Q query_option]\n"
191 );
192 exit(255);
193 }
194
195 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
196 static void load_public_identity_files(const struct ssh_conn_info *);
197 static void main_sigchld_handler(int);
198
199 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
200 static void
tilde_expand_paths(char ** paths,u_int num_paths)201 tilde_expand_paths(char **paths, u_int num_paths)
202 {
203 u_int i;
204 char *cp;
205
206 for (i = 0; i < num_paths; i++) {
207 cp = tilde_expand_filename(paths[i], getuid());
208 free(paths[i]);
209 paths[i] = cp;
210 }
211 }
212
213 /*
214 * Expands the set of percent_expand options used by the majority of keywords
215 * in the client that support percent expansion.
216 * Caller must free returned string.
217 */
218 static char *
default_client_percent_expand(const char * str,const struct ssh_conn_info * cinfo)219 default_client_percent_expand(const char *str,
220 const struct ssh_conn_info *cinfo)
221 {
222 return percent_expand(str,
223 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
224 (char *)NULL);
225 }
226
227 /*
228 * Expands the set of percent_expand options used by the majority of keywords
229 * AND perform environment variable substitution.
230 * Caller must free returned string.
231 */
232 static char *
default_client_percent_dollar_expand(const char * str,const struct ssh_conn_info * cinfo)233 default_client_percent_dollar_expand(const char *str,
234 const struct ssh_conn_info *cinfo)
235 {
236 char *ret;
237
238 ret = percent_dollar_expand(str,
239 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
240 (char *)NULL);
241 if (ret == NULL)
242 fatal("invalid environment variable expansion");
243 return ret;
244 }
245
246 /*
247 * Attempt to resolve a host name / port to a set of addresses and
248 * optionally return any CNAMEs encountered along the way.
249 * Returns NULL on failure.
250 * NB. this function must operate with a options having undefined members.
251 */
252 static struct addrinfo *
resolve_host(const char * name,int port,int logerr,char * cname,size_t clen)253 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
254 {
255 char strport[NI_MAXSERV];
256 const char *errstr = NULL;
257 struct addrinfo hints, *res;
258 int gaierr;
259 LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
260
261 if (port <= 0)
262 port = default_ssh_port();
263 if (cname != NULL)
264 *cname = '\0';
265 debug3_f("lookup %s:%d", name, port);
266
267 snprintf(strport, sizeof strport, "%d", port);
268 memset(&hints, 0, sizeof(hints));
269 hints.ai_family = options.address_family == -1 ?
270 AF_UNSPEC : options.address_family;
271 hints.ai_socktype = SOCK_STREAM;
272 if (cname != NULL)
273 hints.ai_flags = AI_CANONNAME;
274 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
275 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
276 loglevel = SYSLOG_LEVEL_ERROR;
277 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
278 __progname, name, ssh_gai_strerror(gaierr));
279 return NULL;
280 }
281 if (cname != NULL && res->ai_canonname != NULL) {
282 if (!valid_domain(res->ai_canonname, 0, &errstr)) {
283 error("ignoring bad CNAME \"%s\" for host \"%s\": %s",
284 res->ai_canonname, name, errstr);
285 } else if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
286 error_f("host \"%s\" cname \"%s\" too long (max %lu)",
287 name, res->ai_canonname, (u_long)clen);
288 if (clen > 0)
289 *cname = '\0';
290 }
291 }
292 return res;
293 }
294
295 /* Returns non-zero if name can only be an address and not a hostname */
296 static int
is_addr_fast(const char * name)297 is_addr_fast(const char *name)
298 {
299 return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
300 strspn(name, "0123456789.") == strlen(name));
301 }
302
303 /* Returns non-zero if name represents a valid, single address */
304 static int
is_addr(const char * name)305 is_addr(const char *name)
306 {
307 char strport[NI_MAXSERV];
308 struct addrinfo hints, *res;
309
310 if (is_addr_fast(name))
311 return 1;
312
313 snprintf(strport, sizeof strport, "%u", default_ssh_port());
314 memset(&hints, 0, sizeof(hints));
315 hints.ai_family = options.address_family == -1 ?
316 AF_UNSPEC : options.address_family;
317 hints.ai_socktype = SOCK_STREAM;
318 hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
319 if (getaddrinfo(name, strport, &hints, &res) != 0)
320 return 0;
321 if (res == NULL || res->ai_next != NULL) {
322 freeaddrinfo(res);
323 return 0;
324 }
325 freeaddrinfo(res);
326 return 1;
327 }
328
329 /*
330 * Attempt to resolve a numeric host address / port to a single address.
331 * Returns a canonical address string.
332 * Returns NULL on failure.
333 * NB. this function must operate with a options having undefined members.
334 */
335 static struct addrinfo *
resolve_addr(const char * name,int port,char * caddr,size_t clen)336 resolve_addr(const char *name, int port, char *caddr, size_t clen)
337 {
338 char addr[NI_MAXHOST], strport[NI_MAXSERV];
339 struct addrinfo hints, *res;
340 int gaierr;
341
342 if (port <= 0)
343 port = default_ssh_port();
344 snprintf(strport, sizeof strport, "%u", port);
345 memset(&hints, 0, sizeof(hints));
346 hints.ai_family = options.address_family == -1 ?
347 AF_UNSPEC : options.address_family;
348 hints.ai_socktype = SOCK_STREAM;
349 hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
350 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
351 debug2_f("could not resolve name %.100s as address: %s",
352 name, ssh_gai_strerror(gaierr));
353 return NULL;
354 }
355 if (res == NULL) {
356 debug_f("getaddrinfo %.100s returned no addresses", name);
357 return NULL;
358 }
359 if (res->ai_next != NULL) {
360 debug_f("getaddrinfo %.100s returned multiple addresses", name);
361 goto fail;
362 }
363 if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
364 addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
365 debug_f("Could not format address for name %.100s: %s",
366 name, ssh_gai_strerror(gaierr));
367 goto fail;
368 }
369 if (strlcpy(caddr, addr, clen) >= clen) {
370 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
371 name, addr, (u_long)clen);
372 if (clen > 0)
373 *caddr = '\0';
374 fail:
375 freeaddrinfo(res);
376 return NULL;
377 }
378 return res;
379 }
380
381 /*
382 * Check whether the cname is a permitted replacement for the hostname
383 * and perform the replacement if it is.
384 * NB. this function must operate with a options having undefined members.
385 */
386 static int
check_follow_cname(int direct,char ** namep,const char * cname)387 check_follow_cname(int direct, char **namep, const char *cname)
388 {
389 int i;
390 struct allowed_cname *rule;
391
392 if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
393 strcmp(*namep, cname) == 0)
394 return 0;
395 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
396 return 0;
397 /*
398 * Don't attempt to canonicalize names that will be interpreted by
399 * a proxy or jump host unless the user specifically requests so.
400 */
401 if (!direct &&
402 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
403 return 0;
404 debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
405 for (i = 0; i < options.num_permitted_cnames; i++) {
406 rule = options.permitted_cnames + i;
407 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
408 match_pattern_list(cname, rule->target_list, 1) != 1)
409 continue;
410 verbose("Canonicalized DNS aliased hostname "
411 "\"%s\" => \"%s\"", *namep, cname);
412 free(*namep);
413 *namep = xstrdup(cname);
414 return 1;
415 }
416 return 0;
417 }
418
419 /*
420 * Attempt to resolve the supplied hostname after applying the user's
421 * canonicalization rules. Returns the address list for the host or NULL
422 * if no name was found after canonicalization.
423 * NB. this function must operate with a options having undefined members.
424 */
425 static struct addrinfo *
resolve_canonicalize(char ** hostp,int port)426 resolve_canonicalize(char **hostp, int port)
427 {
428 int i, direct, ndots;
429 char *cp, *fullhost, newname[NI_MAXHOST];
430 struct addrinfo *addrs;
431
432 /*
433 * Attempt to canonicalise addresses, regardless of
434 * whether hostname canonicalisation was requested
435 */
436 if ((addrs = resolve_addr(*hostp, port,
437 newname, sizeof(newname))) != NULL) {
438 debug2_f("hostname %.100s is address", *hostp);
439 if (strcasecmp(*hostp, newname) != 0) {
440 debug2_f("canonicalised address \"%s\" => \"%s\"",
441 *hostp, newname);
442 free(*hostp);
443 *hostp = xstrdup(newname);
444 }
445 return addrs;
446 }
447
448 /*
449 * If this looks like an address but didn't parse as one, it might
450 * be an address with an invalid interface scope. Skip further
451 * attempts at canonicalisation.
452 */
453 if (is_addr_fast(*hostp)) {
454 debug_f("hostname %.100s is an unrecognised address", *hostp);
455 return NULL;
456 }
457
458 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
459 return NULL;
460
461 /*
462 * Don't attempt to canonicalize names that will be interpreted by
463 * a proxy unless the user specifically requests so.
464 */
465 direct = option_clear_or_none(options.proxy_command) &&
466 option_clear_or_none(options.jump_host);
467 if (!direct &&
468 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
469 return NULL;
470
471 /* If domain name is anchored, then resolve it now */
472 if ((*hostp)[strlen(*hostp) - 1] == '.') {
473 debug3_f("name is fully qualified");
474 fullhost = xstrdup(*hostp);
475 if ((addrs = resolve_host(fullhost, port, 0,
476 newname, sizeof(newname))) != NULL)
477 goto found;
478 free(fullhost);
479 goto notfound;
480 }
481
482 /* Don't apply canonicalization to sufficiently-qualified hostnames */
483 ndots = 0;
484 for (cp = *hostp; *cp != '\0'; cp++) {
485 if (*cp == '.')
486 ndots++;
487 }
488 if (ndots > options.canonicalize_max_dots) {
489 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
490 *hostp, options.canonicalize_max_dots);
491 return NULL;
492 }
493 /* Attempt each supplied suffix */
494 for (i = 0; i < options.num_canonical_domains; i++) {
495 if (strcasecmp(options.canonical_domains[i], "none") == 0)
496 break;
497 xasprintf(&fullhost, "%s.%s.", *hostp,
498 options.canonical_domains[i]);
499 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
500 if ((addrs = resolve_host(fullhost, port, 0,
501 newname, sizeof(newname))) == NULL) {
502 free(fullhost);
503 continue;
504 }
505 found:
506 /* Remove trailing '.' */
507 fullhost[strlen(fullhost) - 1] = '\0';
508 /* Follow CNAME if requested */
509 if (!check_follow_cname(direct, &fullhost, newname)) {
510 debug("Canonicalized hostname \"%s\" => \"%s\"",
511 *hostp, fullhost);
512 }
513 free(*hostp);
514 *hostp = fullhost;
515 return addrs;
516 }
517 notfound:
518 if (!options.canonicalize_fallback_local)
519 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
520 debug2_f("host %s not found in any suffix", *hostp);
521 return NULL;
522 }
523
524 /*
525 * Check the result of hostkey loading, ignoring some errors and either
526 * discarding the key or fatal()ing for others.
527 */
528 static void
check_load(int r,struct sshkey ** k,const char * path,const char * message)529 check_load(int r, struct sshkey **k, const char *path, const char *message)
530 {
531 switch (r) {
532 case 0:
533 /* Check RSA keys size and discard if undersized */
534 if (k != NULL && *k != NULL &&
535 (r = sshkey_check_rsa_length(*k,
536 options.required_rsa_size)) != 0) {
537 error_r(r, "load %s \"%s\"", message, path);
538 free(*k);
539 *k = NULL;
540 }
541 break;
542 case SSH_ERR_INTERNAL_ERROR:
543 case SSH_ERR_ALLOC_FAIL:
544 fatal_r(r, "load %s \"%s\"", message, path);
545 case SSH_ERR_SYSTEM_ERROR:
546 /* Ignore missing files */
547 if (errno == ENOENT)
548 break;
549 /* FALLTHROUGH */
550 default:
551 error_r(r, "load %s \"%s\"", message, path);
552 break;
553 }
554 }
555
556 /*
557 * Read per-user configuration file. Ignore the system wide config
558 * file if the user specifies a config file on the command line.
559 */
560 static void
process_config_files(const char * host_name,struct passwd * pw,int final_pass,int * want_final_pass)561 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
562 int *want_final_pass)
563 {
564 char buf[PATH_MAX];
565 int r;
566
567 if (config != NULL) {
568 if (strcasecmp(config, "none") != 0 &&
569 !read_config_file(config, pw, host, host_name, &options,
570 SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
571 want_final_pass))
572 fatal("Can't open user config file %.100s: "
573 "%.100s", config, strerror(errno));
574 } else {
575 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
576 _PATH_SSH_USER_CONFFILE);
577 if (r > 0 && (size_t)r < sizeof(buf))
578 (void)read_config_file(buf, pw, host, host_name,
579 &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
580 (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
581
582 /* Read systemwide configuration file after user config. */
583 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
584 host, host_name, &options,
585 final_pass ? SSHCONF_FINAL : 0, want_final_pass);
586 }
587 }
588
589 /* Rewrite the port number in an addrinfo list of addresses */
590 static void
set_addrinfo_port(struct addrinfo * addrs,int port)591 set_addrinfo_port(struct addrinfo *addrs, int port)
592 {
593 struct addrinfo *addr;
594
595 for (addr = addrs; addr != NULL; addr = addr->ai_next) {
596 switch (addr->ai_family) {
597 case AF_INET:
598 ((struct sockaddr_in *)addr->ai_addr)->
599 sin_port = htons(port);
600 break;
601 case AF_INET6:
602 ((struct sockaddr_in6 *)addr->ai_addr)->
603 sin6_port = htons(port);
604 break;
605 }
606 }
607 }
608
609 static void
ssh_conn_info_free(struct ssh_conn_info * cinfo)610 ssh_conn_info_free(struct ssh_conn_info *cinfo)
611 {
612 if (cinfo == NULL)
613 return;
614 free(cinfo->conn_hash_hex);
615 free(cinfo->shorthost);
616 free(cinfo->uidstr);
617 free(cinfo->keyalias);
618 free(cinfo->thishost);
619 free(cinfo->host_arg);
620 free(cinfo->portstr);
621 free(cinfo->remhost);
622 free(cinfo->remuser);
623 free(cinfo->homedir);
624 free(cinfo->locuser);
625 free(cinfo->jmphost);
626 free(cinfo);
627 }
628
629 static int
valid_hostname(const char * s)630 valid_hostname(const char *s)
631 {
632 size_t i;
633
634 if (*s == '-')
635 return 0;
636 for (i = 0; s[i] != 0; i++) {
637 if (strchr("'`\"$\\;&<>|(){}", s[i]) != NULL ||
638 isspace((u_char)s[i]) || iscntrl((u_char)s[i]))
639 return 0;
640 }
641 return 1;
642 }
643
644 static int
valid_ruser(const char * s)645 valid_ruser(const char *s)
646 {
647 size_t i;
648
649 if (*s == '-')
650 return 0;
651 for (i = 0; s[i] != 0; i++) {
652 if (strchr("'`\";&<>|(){}", s[i]) != NULL)
653 return 0;
654 /* Disallow '-' after whitespace */
655 if (isspace((u_char)s[i]) && s[i + 1] == '-')
656 return 0;
657 /* Disallow \ in last position */
658 if (s[i] == '\\' && s[i + 1] == '\0')
659 return 0;
660 }
661 return 1;
662 }
663
664 /*
665 * Main program for the ssh client.
666 */
667 int
main(int ac,char ** av)668 main(int ac, char **av)
669 {
670 struct ssh *ssh = NULL;
671 int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
672 int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
673 char *p, *cp, *line, *argv0, *logfile;
674 char cname[NI_MAXHOST], thishost[NI_MAXHOST];
675 struct stat st;
676 struct passwd *pw;
677 extern int optind, optreset;
678 extern char *optarg;
679 struct Forward fwd;
680 struct addrinfo *addrs = NULL;
681 size_t n, len;
682 u_int j;
683 struct ssh_conn_info *cinfo = NULL;
684
685 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
686 sanitise_stdfd();
687
688 /*
689 * Discard other fds that are hanging around. These can cause problem
690 * with backgrounded ssh processes started by ControlPersist.
691 */
692 closefrom(STDERR_FILENO + 1);
693
694 __progname = ssh_get_progname(av[0]);
695
696 #ifndef HAVE_SETPROCTITLE
697 /* Prepare for later setproctitle emulation */
698 /* Save argv so it isn't clobbered by setproctitle() emulation */
699 saved_av = xcalloc(ac + 1, sizeof(*saved_av));
700 for (i = 0; i < ac; i++)
701 saved_av[i] = xstrdup(av[i]);
702 saved_av[i] = NULL;
703 compat_init_setproctitle(ac, av);
704 av = saved_av;
705 #endif
706
707 seed_rng();
708
709 /* Get user data. */
710 pw = getpwuid(getuid());
711 if (!pw) {
712 logit("No user exists for uid %lu", (u_long)getuid());
713 exit(255);
714 }
715 /* Take a copy of the returned structure. */
716 pw = pwcopy(pw);
717
718 /*
719 * Set our umask to something reasonable, as some files are created
720 * with the default umask. This will make them world-readable but
721 * writable only by the owner, which is ok for all files for which we
722 * don't set the modes explicitly.
723 */
724 umask(022 | umask(077));
725
726 msetlocale();
727
728 /*
729 * Initialize option structure to indicate that no values have been
730 * set.
731 */
732 initialize_options(&options);
733
734 /*
735 * Prepare main ssh transport/connection structures
736 */
737 if ((ssh = ssh_alloc_session_state()) == NULL)
738 fatal("Couldn't allocate session state");
739 channel_init_channels(ssh);
740
741 /* Parse command-line arguments. */
742 host = NULL;
743 use_syslog = 0;
744 logfile = NULL;
745 argv0 = av[0];
746
747 again:
748 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
749 "AB:CD:E:F:GI:J:KL:MNO:P:Q:R:S:TVw:W:XYy")) != -1) { /* HUZdhjruz */
750 switch (opt) {
751 case '1':
752 fatal("SSH protocol v.1 is no longer supported");
753 break;
754 case '2':
755 /* Ignored */
756 break;
757 case '4':
758 options.address_family = AF_INET;
759 break;
760 case '6':
761 options.address_family = AF_INET6;
762 break;
763 case 'n':
764 options.stdin_null = 1;
765 break;
766 case 'f':
767 options.fork_after_authentication = 1;
768 options.stdin_null = 1;
769 break;
770 case 'x':
771 options.forward_x11 = 0;
772 break;
773 case 'X':
774 options.forward_x11 = 1;
775 break;
776 case 'y':
777 use_syslog = 1;
778 break;
779 case 'E':
780 logfile = optarg;
781 break;
782 case 'G':
783 config_test = 1;
784 break;
785 case 'Y':
786 options.forward_x11 = 1;
787 options.forward_x11_trusted = 1;
788 break;
789 case 'g':
790 options.fwd_opts.gateway_ports = 1;
791 break;
792 case 'O':
793 if (options.stdio_forward_host != NULL)
794 fatal("Cannot specify multiplexing "
795 "command with -W");
796 else if (muxclient_command != 0)
797 fatal("Multiplexing command already specified");
798 if (strcmp(optarg, "check") == 0)
799 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
800 else if (strcmp(optarg, "forward") == 0)
801 muxclient_command = SSHMUX_COMMAND_FORWARD;
802 else if (strcmp(optarg, "exit") == 0)
803 muxclient_command = SSHMUX_COMMAND_TERMINATE;
804 else if (strcmp(optarg, "stop") == 0)
805 muxclient_command = SSHMUX_COMMAND_STOP;
806 else if (strcmp(optarg, "cancel") == 0)
807 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
808 else if (strcmp(optarg, "proxy") == 0)
809 muxclient_command = SSHMUX_COMMAND_PROXY;
810 else
811 fatal("Invalid multiplex command.");
812 break;
813 case 'P':
814 if (options.tag == NULL)
815 options.tag = xstrdup(optarg);
816 break;
817 case 'Q':
818 cp = NULL;
819 if (strcmp(optarg, "cipher") == 0 ||
820 strcasecmp(optarg, "Ciphers") == 0)
821 cp = cipher_alg_list('\n', 0);
822 else if (strcmp(optarg, "cipher-auth") == 0)
823 cp = cipher_alg_list('\n', 1);
824 else if (strcmp(optarg, "mac") == 0 ||
825 strcasecmp(optarg, "MACs") == 0)
826 cp = mac_alg_list('\n');
827 else if (strcmp(optarg, "kex") == 0 ||
828 strcasecmp(optarg, "KexAlgorithms") == 0)
829 cp = kex_alg_list('\n');
830 else if (strcmp(optarg, "key") == 0)
831 cp = sshkey_alg_list(0, 0, 0, '\n');
832 else if (strcmp(optarg, "key-cert") == 0)
833 cp = sshkey_alg_list(1, 0, 0, '\n');
834 else if (strcmp(optarg, "key-plain") == 0)
835 cp = sshkey_alg_list(0, 1, 0, '\n');
836 else if (strcmp(optarg, "key-ca-sign") == 0 ||
837 strcasecmp(optarg, "CASignatureAlgorithms") == 0)
838 cp = sshkey_alg_list(0, 1, 1, '\n');
839 else if (strcmp(optarg, "key-sig") == 0 ||
840 strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
841 strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
842 strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
843 strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
844 strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
845 strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
846 cp = sshkey_alg_list(0, 0, 1, '\n');
847 else if (strcmp(optarg, "sig") == 0)
848 cp = sshkey_alg_list(0, 1, 1, '\n');
849 else if (strcmp(optarg, "protocol-version") == 0)
850 cp = xstrdup("2");
851 else if (strcmp(optarg, "compression") == 0) {
852 cp = xstrdup(compression_alg_list(0));
853 len = strlen(cp);
854 for (n = 0; n < len; n++)
855 if (cp[n] == ',')
856 cp[n] = '\n';
857 } else if (strcmp(optarg, "help") == 0) {
858 cp = xstrdup(
859 "cipher\ncipher-auth\ncompression\nkex\n"
860 "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
861 "protocol-version\nsig");
862 }
863 if (cp == NULL)
864 fatal("Unsupported query \"%s\"", optarg);
865 printf("%s\n", cp);
866 free(cp);
867 exit(0);
868 break;
869 case 'a':
870 options.forward_agent = 0;
871 break;
872 case 'A':
873 options.forward_agent = 1;
874 break;
875 case 'k':
876 options.gss_deleg_creds = 0;
877 break;
878 case 'K':
879 options.gss_authentication = 1;
880 options.gss_deleg_creds = 1;
881 break;
882 case 'i':
883 p = tilde_expand_filename(optarg, getuid());
884 if (stat(p, &st) == -1)
885 fprintf(stderr, "Warning: Identity file %s "
886 "not accessible: %s.\n", p,
887 strerror(errno));
888 else
889 add_identity_file(&options, NULL, p, 1);
890 free(p);
891 break;
892 case 'I':
893 #ifdef ENABLE_PKCS11
894 free(options.pkcs11_provider);
895 options.pkcs11_provider = xstrdup(optarg);
896 #else
897 fprintf(stderr, "no support for PKCS#11.\n");
898 #endif
899 break;
900 case 'J':
901 if (options.jump_host != NULL) {
902 fatal("Only a single -J option is permitted "
903 "(use commas to separate multiple "
904 "jump hops)");
905 }
906 if (options.proxy_command != NULL)
907 fatal("Cannot specify -J with ProxyCommand");
908 if (parse_jump(optarg, &options, 1) == -1)
909 fatal("Invalid -J argument");
910 options.proxy_command = xstrdup("none");
911 break;
912 case 't':
913 if (options.request_tty == REQUEST_TTY_YES)
914 options.request_tty = REQUEST_TTY_FORCE;
915 else
916 options.request_tty = REQUEST_TTY_YES;
917 break;
918 case 'v':
919 if (debug_flag == 0) {
920 debug_flag = 1;
921 options.log_level = SYSLOG_LEVEL_DEBUG1;
922 } else {
923 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
924 debug_flag++;
925 options.log_level++;
926 }
927 }
928 break;
929 case 'V':
930 fprintf(stderr, "%s, %s\n",
931 SSH_RELEASE, SSH_OPENSSL_VERSION);
932 exit(0);
933 break;
934 case 'w':
935 if (options.tun_open == -1)
936 options.tun_open = SSH_TUNMODE_DEFAULT;
937 options.tun_local = a2tun(optarg, &options.tun_remote);
938 if (options.tun_local == SSH_TUNID_ERR) {
939 fprintf(stderr,
940 "Bad tun device '%s'\n", optarg);
941 exit(255);
942 }
943 break;
944 case 'W':
945 if (options.stdio_forward_host != NULL)
946 fatal("stdio forward already specified");
947 if (muxclient_command != 0)
948 fatal("Cannot specify stdio forward with -O");
949 if (parse_forward(&fwd, optarg, 1, 0)) {
950 options.stdio_forward_host =
951 fwd.listen_port == PORT_STREAMLOCAL ?
952 fwd.listen_path : fwd.listen_host;
953 options.stdio_forward_port = fwd.listen_port;
954 free(fwd.connect_host);
955 } else {
956 fprintf(stderr,
957 "Bad stdio forwarding specification '%s'\n",
958 optarg);
959 exit(255);
960 }
961 options.request_tty = REQUEST_TTY_NO;
962 options.session_type = SESSION_TYPE_NONE;
963 break;
964 case 'q':
965 options.log_level = SYSLOG_LEVEL_QUIET;
966 break;
967 case 'e':
968 if (optarg[0] == '^' && optarg[2] == 0 &&
969 (u_char) optarg[1] >= 64 &&
970 (u_char) optarg[1] < 128)
971 options.escape_char = (u_char) optarg[1] & 31;
972 else if (strlen(optarg) == 1)
973 options.escape_char = (u_char) optarg[0];
974 else if (strcmp(optarg, "none") == 0)
975 options.escape_char = SSH_ESCAPECHAR_NONE;
976 else {
977 fprintf(stderr, "Bad escape character '%s'.\n",
978 optarg);
979 exit(255);
980 }
981 break;
982 case 'c':
983 if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
984 optarg + 1 : optarg)) {
985 fprintf(stderr, "Unknown cipher type '%s'\n",
986 optarg);
987 exit(255);
988 }
989 free(options.ciphers);
990 options.ciphers = xstrdup(optarg);
991 break;
992 case 'm':
993 if (mac_valid(optarg)) {
994 free(options.macs);
995 options.macs = xstrdup(optarg);
996 } else {
997 fprintf(stderr, "Unknown mac type '%s'\n",
998 optarg);
999 exit(255);
1000 }
1001 break;
1002 case 'M':
1003 if (options.control_master == SSHCTL_MASTER_YES)
1004 options.control_master = SSHCTL_MASTER_ASK;
1005 else
1006 options.control_master = SSHCTL_MASTER_YES;
1007 break;
1008 case 'p':
1009 if (options.port == -1) {
1010 options.port = a2port(optarg);
1011 if (options.port <= 0) {
1012 fprintf(stderr, "Bad port '%s'\n",
1013 optarg);
1014 exit(255);
1015 }
1016 }
1017 break;
1018 case 'l':
1019 if (options.user == NULL)
1020 options.user = optarg;
1021 break;
1022
1023 case 'L':
1024 if (parse_forward(&fwd, optarg, 0, 0))
1025 add_local_forward(&options, &fwd);
1026 else {
1027 fprintf(stderr,
1028 "Bad local forwarding specification '%s'\n",
1029 optarg);
1030 exit(255);
1031 }
1032 break;
1033
1034 case 'R':
1035 if (parse_forward(&fwd, optarg, 0, 1) ||
1036 parse_forward(&fwd, optarg, 1, 1)) {
1037 add_remote_forward(&options, &fwd);
1038 } else {
1039 fprintf(stderr,
1040 "Bad remote forwarding specification "
1041 "'%s'\n", optarg);
1042 exit(255);
1043 }
1044 break;
1045
1046 case 'D':
1047 if (parse_forward(&fwd, optarg, 1, 0)) {
1048 add_local_forward(&options, &fwd);
1049 } else {
1050 fprintf(stderr,
1051 "Bad dynamic forwarding specification "
1052 "'%s'\n", optarg);
1053 exit(255);
1054 }
1055 break;
1056
1057 case 'C':
1058 #ifdef WITH_ZLIB
1059 options.compression = 1;
1060 #else
1061 error("Compression not supported, disabling.");
1062 #endif
1063 break;
1064 case 'N':
1065 if (options.session_type != -1 &&
1066 options.session_type != SESSION_TYPE_NONE)
1067 fatal("Cannot specify -N with -s/SessionType");
1068 options.session_type = SESSION_TYPE_NONE;
1069 options.request_tty = REQUEST_TTY_NO;
1070 break;
1071 case 'T':
1072 options.request_tty = REQUEST_TTY_NO;
1073 break;
1074 case 'o':
1075 line = xstrdup(optarg);
1076 if (process_config_line(&options, pw,
1077 host ? host : "", host ? host : "", line,
1078 "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1079 exit(255);
1080 free(line);
1081 break;
1082 case 's':
1083 if (options.session_type != -1 &&
1084 options.session_type != SESSION_TYPE_SUBSYSTEM)
1085 fatal("Cannot specify -s with -N/SessionType");
1086 options.session_type = SESSION_TYPE_SUBSYSTEM;
1087 break;
1088 case 'S':
1089 free(options.control_path);
1090 options.control_path = xstrdup(optarg);
1091 break;
1092 case 'b':
1093 options.bind_address = optarg;
1094 break;
1095 case 'B':
1096 options.bind_interface = optarg;
1097 break;
1098 case 'F':
1099 config = optarg;
1100 break;
1101 default:
1102 usage();
1103 }
1104 }
1105
1106 if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1107 opt_terminated = 1;
1108
1109 ac -= optind;
1110 av += optind;
1111
1112 if (ac > 0 && !host) {
1113 int tport;
1114 char *tuser;
1115 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1116 case -1:
1117 usage();
1118 break;
1119 case 0:
1120 if (options.user == NULL) {
1121 options.user = tuser;
1122 tuser = NULL;
1123 }
1124 free(tuser);
1125 if (options.port == -1 && tport != -1)
1126 options.port = tport;
1127 break;
1128 default:
1129 p = xstrdup(*av);
1130 cp = strrchr(p, '@');
1131 if (cp != NULL) {
1132 if (cp == p)
1133 usage();
1134 if (options.user == NULL) {
1135 options.user = p;
1136 p = NULL;
1137 }
1138 *cp++ = '\0';
1139 host = xstrdup(cp);
1140 free(p);
1141 } else
1142 host = p;
1143 break;
1144 }
1145 if (ac > 1 && !opt_terminated) {
1146 optind = optreset = 1;
1147 goto again;
1148 }
1149 ac--, av++;
1150 }
1151
1152 /* Check that we got a host name. */
1153 if (!host)
1154 usage();
1155
1156 if (!valid_hostname(host))
1157 fatal("hostname contains invalid characters");
1158 if (options.user != NULL && !valid_ruser(options.user))
1159 fatal("remote username contains invalid characters");
1160 options.host_arg = xstrdup(host);
1161
1162 /* Initialize the command to execute on remote host. */
1163 if ((command = sshbuf_new()) == NULL)
1164 fatal("sshbuf_new failed");
1165
1166 /*
1167 * Save the command to execute on the remote host in a buffer. There
1168 * is no limit on the length of the command, except by the maximum
1169 * packet size. Also sets the tty flag if there is no command.
1170 */
1171 if (!ac) {
1172 /* No command specified - execute shell on a tty. */
1173 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1174 fprintf(stderr,
1175 "You must specify a subsystem to invoke.\n");
1176 usage();
1177 }
1178 } else {
1179 /* A command has been specified. Store it into the buffer. */
1180 for (i = 0; i < ac; i++) {
1181 if ((r = sshbuf_putf(command, "%s%s",
1182 i ? " " : "", av[i])) != 0)
1183 fatal_fr(r, "buffer error");
1184 }
1185 }
1186
1187 ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1188
1189 /*
1190 * Initialize "log" output. Since we are the client all output
1191 * goes to stderr unless otherwise specified by -y or -E.
1192 */
1193 if (use_syslog && logfile != NULL)
1194 fatal("Can't specify both -y and -E");
1195 if (logfile != NULL)
1196 log_redirect_stderr_to(logfile);
1197 log_init(argv0,
1198 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1199 SYSLOG_LEVEL_INFO : options.log_level,
1200 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1201 SYSLOG_FACILITY_USER : options.log_facility,
1202 !use_syslog);
1203
1204 if (debug_flag)
1205 logit("%s, %s", SSH_RELEASE, SSH_OPENSSL_VERSION);
1206
1207 /* Parse the configuration files */
1208 process_config_files(options.host_arg, pw, 0, &want_final_pass);
1209 if (want_final_pass)
1210 debug("configuration requests final Match pass");
1211
1212 /* Hostname canonicalisation needs a few options filled. */
1213 fill_default_options_for_canonicalization(&options);
1214
1215 /* If the user has replaced the hostname then take it into use now */
1216 if (options.hostname != NULL) {
1217 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1218 cp = percent_expand(options.hostname,
1219 "h", host, (char *)NULL);
1220 free(host);
1221 host = cp;
1222 free(options.hostname);
1223 options.hostname = xstrdup(host);
1224 }
1225
1226 /* Don't lowercase addresses, they will be explicitly canonicalised */
1227 if ((was_addr = is_addr(host)) == 0)
1228 lowercase(host);
1229
1230 /*
1231 * Try to canonicalize if requested by configuration or the
1232 * hostname is an address.
1233 */
1234 if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1235 addrs = resolve_canonicalize(&host, options.port);
1236
1237 /*
1238 * If CanonicalizePermittedCNAMEs have been specified but
1239 * other canonicalization did not happen (by not being requested
1240 * or by failing with fallback) then the hostname may still be changed
1241 * as a result of CNAME following.
1242 *
1243 * Try to resolve the bare hostname name using the system resolver's
1244 * usual search rules and then apply the CNAME follow rules.
1245 *
1246 * Skip the lookup if a ProxyCommand is being used unless the user
1247 * has specifically requested canonicalisation for this case via
1248 * CanonicalizeHostname=always
1249 */
1250 direct = option_clear_or_none(options.proxy_command) &&
1251 option_clear_or_none(options.jump_host);
1252 if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1253 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1254 if ((addrs = resolve_host(host, options.port,
1255 direct, cname, sizeof(cname))) == NULL) {
1256 /* Don't fatal proxied host names not in the DNS */
1257 if (direct)
1258 cleanup_exit(255); /* logged in resolve_host */
1259 } else
1260 check_follow_cname(direct, &host, cname);
1261 }
1262
1263 /*
1264 * If canonicalisation is enabled then re-parse the configuration
1265 * files as new stanzas may match.
1266 */
1267 if (options.canonicalize_hostname != 0 && !want_final_pass) {
1268 debug("hostname canonicalisation enabled, "
1269 "will re-parse configuration");
1270 want_final_pass = 1;
1271 }
1272
1273 if (want_final_pass) {
1274 debug("re-parsing configuration");
1275 free(options.hostname);
1276 options.hostname = xstrdup(host);
1277 process_config_files(options.host_arg, pw, 1, NULL);
1278 /*
1279 * Address resolution happens early with canonicalisation
1280 * enabled and the port number may have changed since, so
1281 * reset it in address list
1282 */
1283 if (addrs != NULL && options.port > 0)
1284 set_addrinfo_port(addrs, options.port);
1285 }
1286
1287 /* Fill configuration defaults. */
1288 if (fill_default_options(&options) != 0)
1289 cleanup_exit(255);
1290
1291 if (options.user == NULL)
1292 options.user = xstrdup(pw->pw_name);
1293
1294 /*
1295 * If ProxyJump option specified, then construct a ProxyCommand now.
1296 */
1297 if (options.jump_host != NULL) {
1298 char port_s[8];
1299 const char *jumpuser = options.jump_user, *sshbin = argv0;
1300 int port = options.port, jumpport = options.jump_port;
1301
1302 if (port <= 0)
1303 port = default_ssh_port();
1304 if (jumpport <= 0)
1305 jumpport = default_ssh_port();
1306 if (jumpuser == NULL)
1307 jumpuser = options.user;
1308 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1309 strcmp(options.user, jumpuser) == 0)
1310 fatal("jumphost loop via %s", options.jump_host);
1311
1312 /*
1313 * Try to use SSH indicated by argv[0], but fall back to
1314 * "ssh" if it appears unavailable.
1315 */
1316 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1317 sshbin = "ssh";
1318
1319 /* Consistency check */
1320 if (options.proxy_command != NULL)
1321 fatal("inconsistent options: ProxyCommand+ProxyJump");
1322 /* Never use FD passing for ProxyJump */
1323 options.proxy_use_fdpass = 0;
1324 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1325 xasprintf(&options.proxy_command,
1326 "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1327 sshbin,
1328 /* Optional "-l user" argument if jump_user set */
1329 options.jump_user == NULL ? "" : " -l ",
1330 options.jump_user == NULL ? "" : options.jump_user,
1331 /* Optional "-p port" argument if jump_port set */
1332 options.jump_port <= 0 ? "" : " -p ",
1333 options.jump_port <= 0 ? "" : port_s,
1334 /* Optional additional jump hosts ",..." */
1335 options.jump_extra == NULL ? "" : " -J ",
1336 options.jump_extra == NULL ? "" : options.jump_extra,
1337 /* Optional "-F" argument if -F specified */
1338 config == NULL ? "" : " -F ",
1339 config == NULL ? "" : config,
1340 /* Optional "-v" arguments if -v set */
1341 debug_flag ? " -" : "",
1342 debug_flag, "vvv",
1343 /* Mandatory hostname */
1344 options.jump_host);
1345 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1346 options.proxy_command);
1347 }
1348
1349 if (options.port == 0)
1350 options.port = default_ssh_port();
1351 channel_set_af(ssh, options.address_family);
1352
1353 /* Tidy and check options */
1354 if (options.host_key_alias != NULL)
1355 lowercase(options.host_key_alias);
1356 if (options.proxy_command != NULL &&
1357 strcmp(options.proxy_command, "-") == 0 &&
1358 options.proxy_use_fdpass)
1359 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1360 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1361 if (options.control_persist && options.control_path != NULL) {
1362 debug("UpdateHostKeys=ask is incompatible with "
1363 "ControlPersist; disabling");
1364 options.update_hostkeys = 0;
1365 } else if (sshbuf_len(command) != 0 ||
1366 options.remote_command != NULL ||
1367 options.request_tty == REQUEST_TTY_NO) {
1368 debug("UpdateHostKeys=ask is incompatible with "
1369 "remote command execution; disabling");
1370 options.update_hostkeys = 0;
1371 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1372 /* no point logging anything; user won't see it */
1373 options.update_hostkeys = 0;
1374 }
1375 }
1376 if (options.connection_attempts <= 0)
1377 fatal("Invalid number of ConnectionAttempts");
1378
1379 if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1380 fatal("Cannot execute command-line and remote command.");
1381
1382 /* Cannot fork to background if no command. */
1383 if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1384 options.remote_command == NULL &&
1385 options.session_type != SESSION_TYPE_NONE)
1386 fatal("Cannot fork into background without a command "
1387 "to execute.");
1388
1389 /* reinit */
1390 log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1391 for (j = 0; j < options.num_log_verbose; j++) {
1392 if (strcasecmp(options.log_verbose[j], "none") == 0)
1393 break;
1394 log_verbose_add(options.log_verbose[j]);
1395 }
1396
1397 if (options.request_tty == REQUEST_TTY_YES ||
1398 options.request_tty == REQUEST_TTY_FORCE)
1399 tty_flag = 1;
1400
1401 /* Allocate a tty by default if no command specified. */
1402 if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1403 tty_flag = options.request_tty != REQUEST_TTY_NO;
1404
1405 /* Force no tty */
1406 if (options.request_tty == REQUEST_TTY_NO ||
1407 (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY) ||
1408 options.session_type == SESSION_TYPE_NONE)
1409 tty_flag = 0;
1410 /* Do not allocate a tty if stdin is not a tty. */
1411 if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1412 options.request_tty != REQUEST_TTY_FORCE) {
1413 if (tty_flag)
1414 logit("Pseudo-terminal will not be allocated because "
1415 "stdin is not a terminal.");
1416 tty_flag = 0;
1417 }
1418
1419 /* Set up strings used to percent_expand() arguments */
1420 cinfo = xcalloc(1, sizeof(*cinfo));
1421 if (gethostname(thishost, sizeof(thishost)) == -1)
1422 fatal("gethostname: %s", strerror(errno));
1423 cinfo->thishost = xstrdup(thishost);
1424 thishost[strcspn(thishost, ".")] = '\0';
1425 cinfo->shorthost = xstrdup(thishost);
1426 xasprintf(&cinfo->portstr, "%d", options.port);
1427 xasprintf(&cinfo->uidstr, "%llu",
1428 (unsigned long long)pw->pw_uid);
1429 cinfo->keyalias = xstrdup(options.host_key_alias ?
1430 options.host_key_alias : options.host_arg);
1431 cinfo->host_arg = xstrdup(options.host_arg);
1432 cinfo->remhost = xstrdup(host);
1433 cinfo->remuser = xstrdup(options.user);
1434 cinfo->homedir = xstrdup(pw->pw_dir);
1435 cinfo->locuser = xstrdup(pw->pw_name);
1436 cinfo->jmphost = xstrdup(options.jump_host == NULL ?
1437 "" : options.jump_host);
1438 cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost,
1439 cinfo->remhost, cinfo->portstr, cinfo->remuser, cinfo->jmphost);
1440
1441 /*
1442 * Expand tokens in arguments. NB. LocalCommand is expanded later,
1443 * after port-forwarding is set up, so it may pick up any local
1444 * tunnel interface name allocated.
1445 */
1446 if (options.remote_command != NULL) {
1447 debug3("expanding RemoteCommand: %s", options.remote_command);
1448 cp = options.remote_command;
1449 options.remote_command = default_client_percent_expand(cp,
1450 cinfo);
1451 debug3("expanded RemoteCommand: %s", options.remote_command);
1452 free(cp);
1453 if ((r = sshbuf_put(command, options.remote_command,
1454 strlen(options.remote_command))) != 0)
1455 fatal_fr(r, "buffer error");
1456 }
1457
1458 if (options.control_path != NULL) {
1459 cp = tilde_expand_filename(options.control_path, getuid());
1460 free(options.control_path);
1461 options.control_path = default_client_percent_dollar_expand(cp,
1462 cinfo);
1463 free(cp);
1464 }
1465
1466 if (options.identity_agent != NULL) {
1467 p = tilde_expand_filename(options.identity_agent, getuid());
1468 cp = default_client_percent_dollar_expand(p, cinfo);
1469 free(p);
1470 free(options.identity_agent);
1471 options.identity_agent = cp;
1472 }
1473
1474 if (options.revoked_host_keys != NULL) {
1475 p = tilde_expand_filename(options.revoked_host_keys, getuid());
1476 cp = default_client_percent_dollar_expand(p, cinfo);
1477 free(p);
1478 free(options.revoked_host_keys);
1479 options.revoked_host_keys = cp;
1480 }
1481
1482 if (options.forward_agent_sock_path != NULL) {
1483 p = tilde_expand_filename(options.forward_agent_sock_path,
1484 getuid());
1485 cp = default_client_percent_dollar_expand(p, cinfo);
1486 free(p);
1487 free(options.forward_agent_sock_path);
1488 options.forward_agent_sock_path = cp;
1489 if (stat(options.forward_agent_sock_path, &st) != 0) {
1490 error("Cannot forward agent socket path \"%s\": %s",
1491 options.forward_agent_sock_path, strerror(errno));
1492 if (options.exit_on_forward_failure)
1493 cleanup_exit(255);
1494 }
1495 }
1496
1497 if (options.num_system_hostfiles > 0 &&
1498 strcasecmp(options.system_hostfiles[0], "none") == 0) {
1499 if (options.num_system_hostfiles > 1)
1500 fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1501 "appears with other entries");
1502 free(options.system_hostfiles[0]);
1503 options.system_hostfiles[0] = NULL;
1504 options.num_system_hostfiles = 0;
1505 }
1506
1507 if (options.num_user_hostfiles > 0 &&
1508 strcasecmp(options.user_hostfiles[0], "none") == 0) {
1509 if (options.num_user_hostfiles > 1)
1510 fatal("Invalid UserKnownHostsFiles: \"none\" "
1511 "appears with other entries");
1512 free(options.user_hostfiles[0]);
1513 options.user_hostfiles[0] = NULL;
1514 options.num_user_hostfiles = 0;
1515 }
1516 for (j = 0; j < options.num_user_hostfiles; j++) {
1517 if (options.user_hostfiles[j] == NULL)
1518 continue;
1519 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1520 p = default_client_percent_dollar_expand(cp, cinfo);
1521 if (strcmp(options.user_hostfiles[j], p) != 0)
1522 debug3("expanded UserKnownHostsFile '%s' -> "
1523 "'%s'", options.user_hostfiles[j], p);
1524 free(options.user_hostfiles[j]);
1525 free(cp);
1526 options.user_hostfiles[j] = p;
1527 }
1528
1529 for (i = 0; i < options.num_local_forwards; i++) {
1530 if (options.local_forwards[i].listen_path != NULL) {
1531 cp = options.local_forwards[i].listen_path;
1532 p = options.local_forwards[i].listen_path =
1533 default_client_percent_expand(cp, cinfo);
1534 if (strcmp(cp, p) != 0)
1535 debug3("expanded LocalForward listen path "
1536 "'%s' -> '%s'", cp, p);
1537 free(cp);
1538 }
1539 if (options.local_forwards[i].connect_path != NULL) {
1540 cp = options.local_forwards[i].connect_path;
1541 p = options.local_forwards[i].connect_path =
1542 default_client_percent_expand(cp, cinfo);
1543 if (strcmp(cp, p) != 0)
1544 debug3("expanded LocalForward connect path "
1545 "'%s' -> '%s'", cp, p);
1546 free(cp);
1547 }
1548 }
1549
1550 for (i = 0; i < options.num_remote_forwards; i++) {
1551 if (options.remote_forwards[i].listen_path != NULL) {
1552 cp = options.remote_forwards[i].listen_path;
1553 p = options.remote_forwards[i].listen_path =
1554 default_client_percent_expand(cp, cinfo);
1555 if (strcmp(cp, p) != 0)
1556 debug3("expanded RemoteForward listen path "
1557 "'%s' -> '%s'", cp, p);
1558 free(cp);
1559 }
1560 if (options.remote_forwards[i].connect_path != NULL) {
1561 cp = options.remote_forwards[i].connect_path;
1562 p = options.remote_forwards[i].connect_path =
1563 default_client_percent_expand(cp, cinfo);
1564 if (strcmp(cp, p) != 0)
1565 debug3("expanded RemoteForward connect path "
1566 "'%s' -> '%s'", cp, p);
1567 free(cp);
1568 }
1569 }
1570
1571 if (config_test) {
1572 dump_client_config(&options, host);
1573 exit(0);
1574 }
1575
1576 /* Expand SecurityKeyProvider if it refers to an environment variable */
1577 if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1578 strlen(options.sk_provider) > 1) {
1579 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1580 debug("Authenticator provider %s did not resolve; "
1581 "disabling", options.sk_provider);
1582 free(options.sk_provider);
1583 options.sk_provider = NULL;
1584 } else {
1585 debug2("resolved SecurityKeyProvider %s => %s",
1586 options.sk_provider, cp);
1587 free(options.sk_provider);
1588 options.sk_provider = xstrdup(cp);
1589 }
1590 }
1591
1592 if (muxclient_command != 0 && options.control_path == NULL)
1593 fatal("No ControlPath specified for \"-O\" command");
1594 if (options.control_path != NULL) {
1595 int sock;
1596 if ((sock = muxclient(options.control_path)) >= 0) {
1597 ssh_packet_set_connection(ssh, sock, sock);
1598 ssh_packet_set_mux(ssh);
1599 goto skip_connect;
1600 }
1601 }
1602
1603 /*
1604 * If hostname canonicalisation was not enabled, then we may not
1605 * have yet resolved the hostname. Do so now.
1606 */
1607 if (addrs == NULL && options.proxy_command == NULL) {
1608 debug2("resolving \"%s\" port %d", host, options.port);
1609 if ((addrs = resolve_host(host, options.port, 1,
1610 cname, sizeof(cname))) == NULL)
1611 cleanup_exit(255); /* resolve_host logs the error */
1612 }
1613
1614 if (options.connection_timeout >= INT_MAX/1000)
1615 timeout_ms = INT_MAX;
1616 else
1617 timeout_ms = options.connection_timeout * 1000;
1618
1619 /* Apply channels timeouts, if set */
1620 channel_clear_timeouts(ssh);
1621 for (j = 0; j < options.num_channel_timeouts; j++) {
1622 debug3("applying channel timeout %s",
1623 options.channel_timeouts[j]);
1624 if (parse_pattern_interval(options.channel_timeouts[j],
1625 &cp, &i) != 0) {
1626 fatal_f("internal error: bad timeout %s",
1627 options.channel_timeouts[j]);
1628 }
1629 channel_add_timeout(ssh, cp, i);
1630 free(cp);
1631 }
1632
1633 /* Open a connection to the remote host. */
1634 if (ssh_connect(ssh, host, options.host_arg, addrs, &hostaddr,
1635 options.port, options.connection_attempts,
1636 &timeout_ms, options.tcp_keep_alive) != 0)
1637 exit(255);
1638
1639 if (addrs != NULL)
1640 freeaddrinfo(addrs);
1641
1642 ssh_packet_set_timeout(ssh, options.server_alive_interval,
1643 options.server_alive_count_max);
1644
1645 if (timeout_ms > 0)
1646 debug3("timeout: %d ms remain after connect", timeout_ms);
1647
1648 /*
1649 * If we successfully made the connection and we have hostbased auth
1650 * enabled, load the public keys so we can later use the ssh-keysign
1651 * helper to sign challenges.
1652 */
1653 sensitive_data.nkeys = 0;
1654 sensitive_data.keys = NULL;
1655 if (options.hostbased_authentication) {
1656 int loaded = 0;
1657
1658 sensitive_data.nkeys = 10;
1659 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1660 sizeof(*sensitive_data.keys));
1661
1662 /* XXX check errors? */
1663 #define L_PUBKEY(p,o) do { \
1664 if ((o) >= sensitive_data.nkeys) \
1665 fatal_f("pubkey out of array bounds"); \
1666 check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1667 &(sensitive_data.keys[o]), p, "pubkey"); \
1668 if (sensitive_data.keys[o] != NULL) { \
1669 debug2("hostbased key %d: %s key from \"%s\"", o, \
1670 sshkey_ssh_name(sensitive_data.keys[o]), p); \
1671 loaded++; \
1672 } \
1673 } while (0)
1674 #define L_CERT(p,o) do { \
1675 if ((o) >= sensitive_data.nkeys) \
1676 fatal_f("cert out of array bounds"); \
1677 check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), \
1678 &(sensitive_data.keys[o]), p, "cert"); \
1679 if (sensitive_data.keys[o] != NULL) { \
1680 debug2("hostbased key %d: %s cert from \"%s\"", o, \
1681 sshkey_ssh_name(sensitive_data.keys[o]), p); \
1682 loaded++; \
1683 } \
1684 } while (0)
1685
1686 if (options.hostbased_authentication == 1) {
1687 L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1688 L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1689 L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1690 #ifdef WITH_DSA
1691 L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1692 #endif
1693 L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1694 L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1695 L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1696 #ifdef WITH_DSA
1697 L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1698 #endif
1699 L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1700 L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1701 if (loaded == 0)
1702 debug("HostbasedAuthentication enabled but no "
1703 "local public host keys could be loaded.");
1704 }
1705 }
1706
1707 /* load options.identity_files */
1708 load_public_identity_files(cinfo);
1709
1710 /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1711 if (options.identity_agent &&
1712 strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1713 if (strcmp(options.identity_agent, "none") == 0) {
1714 unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1715 } else {
1716 cp = options.identity_agent;
1717 /* legacy (limited) format */
1718 if (cp[0] == '$' && cp[1] != '{') {
1719 if (!valid_env_name(cp + 1)) {
1720 fatal("Invalid IdentityAgent "
1721 "environment variable name %s", cp);
1722 }
1723 if ((p = getenv(cp + 1)) == NULL)
1724 unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1725 else
1726 setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1727 } else {
1728 /* identity_agent specifies a path directly */
1729 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1730 }
1731 }
1732 }
1733
1734 if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1735 cp = options.forward_agent_sock_path;
1736 if (cp[0] == '$') {
1737 if (!valid_env_name(cp + 1)) {
1738 fatal("Invalid ForwardAgent environment variable name %s", cp);
1739 }
1740 if ((p = getenv(cp + 1)) != NULL)
1741 forward_agent_sock_path = xstrdup(p);
1742 else
1743 options.forward_agent = 0;
1744 free(cp);
1745 } else {
1746 forward_agent_sock_path = cp;
1747 }
1748 }
1749
1750 /* Expand ~ in known host file names. */
1751 tilde_expand_paths(options.system_hostfiles,
1752 options.num_system_hostfiles);
1753 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1754
1755 ssh_signal(SIGCHLD, main_sigchld_handler);
1756
1757 /* Log into the remote system. Never returns if the login fails. */
1758 ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1759 options.port, pw, timeout_ms, cinfo);
1760
1761 /* We no longer need the private host keys. Clear them now. */
1762 if (sensitive_data.nkeys != 0) {
1763 for (i = 0; i < sensitive_data.nkeys; i++) {
1764 if (sensitive_data.keys[i] != NULL) {
1765 /* Destroys contents safely */
1766 debug3("clear hostkey %d", i);
1767 sshkey_free(sensitive_data.keys[i]);
1768 sensitive_data.keys[i] = NULL;
1769 }
1770 }
1771 free(sensitive_data.keys);
1772 }
1773 for (i = 0; i < options.num_identity_files; i++) {
1774 free(options.identity_files[i]);
1775 options.identity_files[i] = NULL;
1776 if (options.identity_keys[i]) {
1777 sshkey_free(options.identity_keys[i]);
1778 options.identity_keys[i] = NULL;
1779 }
1780 }
1781 for (i = 0; i < options.num_certificate_files; i++) {
1782 free(options.certificate_files[i]);
1783 options.certificate_files[i] = NULL;
1784 }
1785
1786 #ifdef ENABLE_PKCS11
1787 (void)pkcs11_del_provider(options.pkcs11_provider);
1788 #endif
1789
1790 skip_connect:
1791 exit_status = ssh_session2(ssh, cinfo);
1792 ssh_conn_info_free(cinfo);
1793 ssh_packet_close(ssh);
1794
1795 if (options.control_path != NULL && muxserver_sock != -1)
1796 unlink(options.control_path);
1797
1798 /* Kill ProxyCommand if it is running. */
1799 ssh_kill_proxy_command();
1800
1801 return exit_status;
1802 }
1803
1804 static void
control_persist_detach(void)1805 control_persist_detach(void)
1806 {
1807 pid_t pid;
1808
1809 debug_f("backgrounding master process");
1810
1811 /*
1812 * master (current process) into the background, and make the
1813 * foreground process a client of the backgrounded master.
1814 */
1815 switch ((pid = fork())) {
1816 case -1:
1817 fatal_f("fork: %s", strerror(errno));
1818 case 0:
1819 /* Child: master process continues mainloop */
1820 break;
1821 default:
1822 /*
1823 * Parent: set up mux client to connect to backgrounded
1824 * master.
1825 */
1826 debug2_f("background process is %ld", (long)pid);
1827 options.stdin_null = ostdin_null_flag;
1828 options.request_tty = orequest_tty;
1829 tty_flag = otty_flag;
1830 options.fork_after_authentication = ofork_after_authentication;
1831 options.session_type = osession_type;
1832 close(muxserver_sock);
1833 muxserver_sock = -1;
1834 options.control_master = SSHCTL_MASTER_NO;
1835 (void)muxclient(options.control_path);
1836 /* muxclient() doesn't return on success. */
1837 fatal("Failed to connect to new control master");
1838 }
1839 if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1840 error_f("stdfd_devnull failed");
1841 daemon(1, 1);
1842 setproctitle("%s [mux]", options.control_path);
1843 }
1844
1845 /* Do fork() after authentication. Used by "ssh -f" */
1846 static void
fork_postauth(void)1847 fork_postauth(void)
1848 {
1849 if (need_controlpersist_detach)
1850 control_persist_detach();
1851 debug("forking to background");
1852 options.fork_after_authentication = 0;
1853 if (daemon(1, 1) == -1)
1854 fatal("daemon() failed: %.200s", strerror(errno));
1855 if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1856 error_f("stdfd_devnull failed");
1857 }
1858
1859 static void
forwarding_success(void)1860 forwarding_success(void)
1861 {
1862 if (forward_confirms_pending == -1)
1863 return;
1864 if (--forward_confirms_pending == 0) {
1865 debug_f("all expected forwarding replies received");
1866 if (options.fork_after_authentication)
1867 fork_postauth();
1868 } else {
1869 debug2_f("%d expected forwarding replies remaining",
1870 forward_confirms_pending);
1871 }
1872 }
1873
1874 /* Callback for remote forward global requests */
1875 static void
ssh_confirm_remote_forward(struct ssh * ssh,int type,u_int32_t seq,void * ctxt)1876 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1877 {
1878 struct Forward *rfwd = (struct Forward *)ctxt;
1879 u_int port;
1880 int r;
1881
1882 /* XXX verbose() on failure? */
1883 debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1884 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1885 rfwd->listen_path ? rfwd->listen_path :
1886 rfwd->listen_host ? rfwd->listen_host : "",
1887 (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1888 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1889 rfwd->connect_host, rfwd->connect_port);
1890 if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1891 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1892 if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1893 fatal_fr(r, "parse packet");
1894 if (port > 65535) {
1895 error("Invalid allocated port %u for remote "
1896 "forward to %s:%d", port,
1897 rfwd->connect_host, rfwd->connect_port);
1898 /* Ensure failure processing runs below */
1899 type = SSH2_MSG_REQUEST_FAILURE;
1900 channel_update_permission(ssh,
1901 rfwd->handle, -1);
1902 } else {
1903 rfwd->allocated_port = (int)port;
1904 logit("Allocated port %u for remote "
1905 "forward to %s:%d",
1906 rfwd->allocated_port, rfwd->connect_path ?
1907 rfwd->connect_path : rfwd->connect_host,
1908 rfwd->connect_port);
1909 channel_update_permission(ssh,
1910 rfwd->handle, rfwd->allocated_port);
1911 }
1912 } else {
1913 channel_update_permission(ssh, rfwd->handle, -1);
1914 }
1915 }
1916
1917 if (type == SSH2_MSG_REQUEST_FAILURE) {
1918 if (options.exit_on_forward_failure) {
1919 if (rfwd->listen_path != NULL)
1920 fatal("Error: remote port forwarding failed "
1921 "for listen path %s", rfwd->listen_path);
1922 else
1923 fatal("Error: remote port forwarding failed "
1924 "for listen port %d", rfwd->listen_port);
1925 } else {
1926 if (rfwd->listen_path != NULL)
1927 logit("Warning: remote port forwarding failed "
1928 "for listen path %s", rfwd->listen_path);
1929 else
1930 logit("Warning: remote port forwarding failed "
1931 "for listen port %d", rfwd->listen_port);
1932 }
1933 }
1934 forwarding_success();
1935 }
1936
1937 static void
client_cleanup_stdio_fwd(struct ssh * ssh,int id,int force,void * arg)1938 client_cleanup_stdio_fwd(struct ssh *ssh, int id, int force, void *arg)
1939 {
1940 debug("stdio forwarding: done");
1941 cleanup_exit(0);
1942 }
1943
1944 static void
ssh_stdio_confirm(struct ssh * ssh,int id,int success,void * arg)1945 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1946 {
1947 if (!success)
1948 fatal("stdio forwarding failed");
1949 }
1950
1951 static void
ssh_tun_confirm(struct ssh * ssh,int id,int success,void * arg)1952 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1953 {
1954 if (!success) {
1955 error("Tunnel forwarding failed");
1956 if (options.exit_on_forward_failure)
1957 cleanup_exit(255);
1958 }
1959
1960 debug_f("tunnel forward established, id=%d", id);
1961 forwarding_success();
1962 }
1963
1964 static void
ssh_init_stdio_forwarding(struct ssh * ssh)1965 ssh_init_stdio_forwarding(struct ssh *ssh)
1966 {
1967 Channel *c;
1968 int in, out;
1969
1970 if (options.stdio_forward_host == NULL)
1971 return;
1972
1973 debug3_f("%s:%d", options.stdio_forward_host,
1974 options.stdio_forward_port);
1975
1976 if ((in = dup(STDIN_FILENO)) == -1 ||
1977 (out = dup(STDOUT_FILENO)) == -1)
1978 fatal_f("dup() in/out failed");
1979 if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1980 options.stdio_forward_port, in, out,
1981 CHANNEL_NONBLOCK_STDIO)) == NULL)
1982 fatal_f("channel_connect_stdio_fwd failed");
1983 channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1984 channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1985 }
1986
1987 static void
ssh_init_forward_permissions(struct ssh * ssh,const char * what,char ** opens,u_int num_opens)1988 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1989 u_int num_opens)
1990 {
1991 u_int i;
1992 int port;
1993 char *addr, *arg, *oarg;
1994 int where = FORWARD_LOCAL;
1995
1996 channel_clear_permission(ssh, FORWARD_ADM, where);
1997 if (num_opens == 0)
1998 return; /* permit any */
1999
2000 /* handle keywords: "any" / "none" */
2001 if (num_opens == 1 && strcmp(opens[0], "any") == 0)
2002 return;
2003 if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
2004 channel_disable_admin(ssh, where);
2005 return;
2006 }
2007 /* Otherwise treat it as a list of permitted host:port */
2008 for (i = 0; i < num_opens; i++) {
2009 oarg = arg = xstrdup(opens[i]);
2010 addr = hpdelim(&arg);
2011 if (addr == NULL)
2012 fatal_f("missing host in %s", what);
2013 addr = cleanhostname(addr);
2014 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
2015 fatal_f("bad port number in %s", what);
2016 /* Send it to channels layer */
2017 channel_add_permission(ssh, FORWARD_ADM,
2018 where, addr, port);
2019 free(oarg);
2020 }
2021 }
2022
2023 static void
ssh_init_forwarding(struct ssh * ssh,char ** ifname)2024 ssh_init_forwarding(struct ssh *ssh, char **ifname)
2025 {
2026 int success = 0;
2027 int i;
2028
2029 ssh_init_forward_permissions(ssh, "permitremoteopen",
2030 options.permitted_remote_opens,
2031 options.num_permitted_remote_opens);
2032
2033 if (options.exit_on_forward_failure)
2034 forward_confirms_pending = 0; /* track pending requests */
2035 /* Initiate local TCP/IP port forwardings. */
2036 for (i = 0; i < options.num_local_forwards; i++) {
2037 debug("Local connections to %.200s:%d forwarded to remote "
2038 "address %.200s:%d",
2039 (options.local_forwards[i].listen_path != NULL) ?
2040 options.local_forwards[i].listen_path :
2041 (options.local_forwards[i].listen_host == NULL) ?
2042 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
2043 options.local_forwards[i].listen_host,
2044 options.local_forwards[i].listen_port,
2045 (options.local_forwards[i].connect_path != NULL) ?
2046 options.local_forwards[i].connect_path :
2047 options.local_forwards[i].connect_host,
2048 options.local_forwards[i].connect_port);
2049 success += channel_setup_local_fwd_listener(ssh,
2050 &options.local_forwards[i], &options.fwd_opts);
2051 }
2052 if (i > 0 && success != i && options.exit_on_forward_failure)
2053 fatal("Could not request local forwarding.");
2054 if (i > 0 && success == 0)
2055 error("Could not request local forwarding.");
2056
2057 /* Initiate remote TCP/IP port forwardings. */
2058 for (i = 0; i < options.num_remote_forwards; i++) {
2059 debug("Remote connections from %.200s:%d forwarded to "
2060 "local address %.200s:%d",
2061 (options.remote_forwards[i].listen_path != NULL) ?
2062 options.remote_forwards[i].listen_path :
2063 (options.remote_forwards[i].listen_host == NULL) ?
2064 "LOCALHOST" : options.remote_forwards[i].listen_host,
2065 options.remote_forwards[i].listen_port,
2066 (options.remote_forwards[i].connect_path != NULL) ?
2067 options.remote_forwards[i].connect_path :
2068 options.remote_forwards[i].connect_host,
2069 options.remote_forwards[i].connect_port);
2070 if ((options.remote_forwards[i].handle =
2071 channel_request_remote_forwarding(ssh,
2072 &options.remote_forwards[i])) >= 0) {
2073 client_register_global_confirm(
2074 ssh_confirm_remote_forward,
2075 &options.remote_forwards[i]);
2076 forward_confirms_pending++;
2077 } else if (options.exit_on_forward_failure)
2078 fatal("Could not request remote forwarding.");
2079 else
2080 logit("Warning: Could not request remote forwarding.");
2081 }
2082
2083 /* Initiate tunnel forwarding. */
2084 if (options.tun_open != SSH_TUNMODE_NO) {
2085 if ((*ifname = client_request_tun_fwd(ssh,
2086 options.tun_open, options.tun_local,
2087 options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
2088 forward_confirms_pending++;
2089 else if (options.exit_on_forward_failure)
2090 fatal("Could not request tunnel forwarding.");
2091 else
2092 error("Could not request tunnel forwarding.");
2093 }
2094 if (forward_confirms_pending > 0) {
2095 debug_f("expecting replies for %d forwards",
2096 forward_confirms_pending);
2097 }
2098 }
2099
2100 static void
check_agent_present(void)2101 check_agent_present(void)
2102 {
2103 int r;
2104
2105 if (options.forward_agent) {
2106 /* Clear agent forwarding if we don't have an agent. */
2107 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2108 options.forward_agent = 0;
2109 if (r != SSH_ERR_AGENT_NOT_PRESENT)
2110 debug_r(r, "ssh_get_authentication_socket");
2111 }
2112 }
2113 }
2114
2115 static void
ssh_session2_setup(struct ssh * ssh,int id,int success,void * arg)2116 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2117 {
2118 extern char **environ;
2119 const char *display, *term;
2120 int r, interactive = tty_flag;
2121 char *proto = NULL, *data = NULL;
2122
2123 if (!success)
2124 return; /* No need for error message, channels code sends one */
2125
2126 display = getenv("DISPLAY");
2127 if (display == NULL && options.forward_x11)
2128 debug("X11 forwarding requested but DISPLAY not set");
2129 if (options.forward_x11 && client_x11_get_proto(ssh, display,
2130 options.xauth_location, options.forward_x11_trusted,
2131 options.forward_x11_timeout, &proto, &data) == 0) {
2132 /* Request forwarding with authentication spoofing. */
2133 debug("Requesting X11 forwarding with authentication "
2134 "spoofing.");
2135 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2136 data, 1);
2137 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2138 /* XXX exit_on_forward_failure */
2139 interactive = 1;
2140 }
2141
2142 check_agent_present();
2143 if (options.forward_agent) {
2144 debug("Requesting authentication agent forwarding.");
2145 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2146 if ((r = sshpkt_send(ssh)) != 0)
2147 fatal_fr(r, "send packet");
2148 }
2149
2150 /* Tell the packet module whether this is an interactive session. */
2151 ssh_packet_set_interactive(ssh, interactive,
2152 options.ip_qos_interactive, options.ip_qos_bulk);
2153
2154 if ((term = lookup_env_in_list("TERM", options.setenv,
2155 options.num_setenv)) == NULL || *term == '\0')
2156 term = getenv("TERM");
2157 client_session2_setup(ssh, id, tty_flag,
2158 options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2159 NULL, fileno(stdin), command, environ);
2160 }
2161
2162 /* open new channel for a session */
2163 static int
ssh_session2_open(struct ssh * ssh)2164 ssh_session2_open(struct ssh *ssh)
2165 {
2166 Channel *c;
2167 int window, packetmax, in, out, err;
2168
2169 if (options.stdin_null) {
2170 in = open(_PATH_DEVNULL, O_RDONLY);
2171 } else {
2172 in = dup(STDIN_FILENO);
2173 }
2174 out = dup(STDOUT_FILENO);
2175 err = dup(STDERR_FILENO);
2176
2177 if (in == -1 || out == -1 || err == -1)
2178 fatal("dup() in/out/err failed");
2179
2180 window = CHAN_SES_WINDOW_DEFAULT;
2181 packetmax = CHAN_SES_PACKET_DEFAULT;
2182 if (tty_flag) {
2183 window >>= 1;
2184 packetmax >>= 1;
2185 }
2186 c = channel_new(ssh,
2187 "session", SSH_CHANNEL_OPENING, in, out, err,
2188 window, packetmax, CHAN_EXTENDED_WRITE,
2189 "client-session", CHANNEL_NONBLOCK_STDIO);
2190
2191 debug3_f("channel_new: %d", c->self);
2192
2193 channel_send_open(ssh, c->self);
2194 if (options.session_type != SESSION_TYPE_NONE)
2195 channel_register_open_confirm(ssh, c->self,
2196 ssh_session2_setup, NULL);
2197
2198 return c->self;
2199 }
2200
2201 static int
ssh_session2(struct ssh * ssh,const struct ssh_conn_info * cinfo)2202 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2203 {
2204 int r, interactive, id = -1;
2205 char *cp, *tun_fwd_ifname = NULL;
2206
2207 /* XXX should be pre-session */
2208 if (!options.control_persist)
2209 ssh_init_stdio_forwarding(ssh);
2210
2211 ssh_init_forwarding(ssh, &tun_fwd_ifname);
2212
2213 if (options.local_command != NULL) {
2214 debug3("expanding LocalCommand: %s", options.local_command);
2215 cp = options.local_command;
2216 options.local_command = percent_expand(cp,
2217 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2218 "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2219 (char *)NULL);
2220 debug3("expanded LocalCommand: %s", options.local_command);
2221 free(cp);
2222 }
2223
2224 /* Start listening for multiplex clients */
2225 if (!ssh_packet_get_mux(ssh))
2226 muxserver_listen(ssh);
2227
2228 /*
2229 * If we are in control persist mode and have a working mux listen
2230 * socket, then prepare to background ourselves and have a foreground
2231 * client attach as a control client.
2232 * NB. we must save copies of the flags that we override for
2233 * the backgrounding, since we defer attachment of the client until
2234 * after the connection is fully established (in particular,
2235 * async rfwd replies have been received for ExitOnForwardFailure).
2236 */
2237 if (options.control_persist && muxserver_sock != -1) {
2238 ostdin_null_flag = options.stdin_null;
2239 osession_type = options.session_type;
2240 orequest_tty = options.request_tty;
2241 otty_flag = tty_flag;
2242 ofork_after_authentication = options.fork_after_authentication;
2243 options.stdin_null = 1;
2244 options.session_type = SESSION_TYPE_NONE;
2245 tty_flag = 0;
2246 if ((osession_type != SESSION_TYPE_NONE ||
2247 options.stdio_forward_host != NULL))
2248 need_controlpersist_detach = 1;
2249 options.fork_after_authentication = 1;
2250 }
2251 /*
2252 * ControlPersist mux listen socket setup failed, attempt the
2253 * stdio forward setup that we skipped earlier.
2254 */
2255 if (options.control_persist && muxserver_sock == -1)
2256 ssh_init_stdio_forwarding(ssh);
2257
2258 if (options.session_type != SESSION_TYPE_NONE)
2259 id = ssh_session2_open(ssh);
2260 else {
2261 interactive = options.control_master == SSHCTL_MASTER_NO;
2262 /* ControlPersist may have clobbered ControlMaster, so check */
2263 if (need_controlpersist_detach)
2264 interactive = otty_flag != 0;
2265 ssh_packet_set_interactive(ssh, interactive,
2266 options.ip_qos_interactive, options.ip_qos_bulk);
2267 }
2268
2269 /* If we don't expect to open a new session, then disallow it */
2270 if (options.control_master == SSHCTL_MASTER_NO &&
2271 (ssh->compat & SSH_NEW_OPENSSH)) {
2272 debug("Requesting no-more-sessions@openssh.com");
2273 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2274 (r = sshpkt_put_cstring(ssh,
2275 "no-more-sessions@openssh.com")) != 0 ||
2276 (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2277 (r = sshpkt_send(ssh)) != 0)
2278 fatal_fr(r, "send packet");
2279 }
2280
2281 /* Execute a local command */
2282 if (options.local_command != NULL &&
2283 options.permit_local_command)
2284 ssh_local_cmd(options.local_command);
2285
2286 /*
2287 * stdout is now owned by the session channel; clobber it here
2288 * so future channel closes are propagated to the local fd.
2289 * NB. this can only happen after LocalCommand has completed,
2290 * as it may want to write to stdout.
2291 */
2292 if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2293 error_f("stdfd_devnull failed");
2294
2295 /*
2296 * If requested and we are not interested in replies to remote
2297 * forwarding requests, then let ssh continue in the background.
2298 */
2299 if (options.fork_after_authentication) {
2300 if (options.exit_on_forward_failure &&
2301 options.num_remote_forwards > 0) {
2302 debug("deferring postauth fork until remote forward "
2303 "confirmation received");
2304 } else
2305 fork_postauth();
2306 }
2307
2308 return client_loop(ssh, tty_flag, tty_flag ?
2309 options.escape_char : SSH_ESCAPECHAR_NONE, id);
2310 }
2311
2312 /* Loads all IdentityFile and CertificateFile keys */
2313 static void
load_public_identity_files(const struct ssh_conn_info * cinfo)2314 load_public_identity_files(const struct ssh_conn_info *cinfo)
2315 {
2316 char *filename, *cp;
2317 struct sshkey *public;
2318 int i;
2319 u_int n_ids, n_certs;
2320 char *identity_files[SSH_MAX_IDENTITY_FILES];
2321 struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2322 int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2323 char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2324 struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2325 int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2326 #ifdef ENABLE_PKCS11
2327 struct sshkey **keys = NULL;
2328 char **comments = NULL;
2329 int nkeys;
2330 #endif /* PKCS11 */
2331
2332 n_ids = n_certs = 0;
2333 memset(identity_files, 0, sizeof(identity_files));
2334 memset(identity_keys, 0, sizeof(identity_keys));
2335 memset(identity_file_userprovided, 0,
2336 sizeof(identity_file_userprovided));
2337 memset(certificate_files, 0, sizeof(certificate_files));
2338 memset(certificates, 0, sizeof(certificates));
2339 memset(certificate_file_userprovided, 0,
2340 sizeof(certificate_file_userprovided));
2341
2342 #ifdef ENABLE_PKCS11
2343 if (options.pkcs11_provider != NULL &&
2344 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2345 (pkcs11_init(!options.batch_mode) == 0) &&
2346 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2347 &keys, &comments)) > 0) {
2348 for (i = 0; i < nkeys; i++) {
2349 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2350 sshkey_free(keys[i]);
2351 free(comments[i]);
2352 continue;
2353 }
2354 identity_keys[n_ids] = keys[i];
2355 identity_files[n_ids] = comments[i]; /* transferred */
2356 n_ids++;
2357 }
2358 free(keys);
2359 free(comments);
2360 }
2361 #endif /* ENABLE_PKCS11 */
2362 for (i = 0; i < options.num_identity_files; i++) {
2363 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2364 strcasecmp(options.identity_files[i], "none") == 0) {
2365 free(options.identity_files[i]);
2366 options.identity_files[i] = NULL;
2367 continue;
2368 }
2369 cp = tilde_expand_filename(options.identity_files[i], getuid());
2370 filename = default_client_percent_dollar_expand(cp, cinfo);
2371 free(cp);
2372 check_load(sshkey_load_public(filename, &public, NULL),
2373 &public, filename, "pubkey");
2374 debug("identity file %s type %d", filename,
2375 public ? public->type : -1);
2376 free(options.identity_files[i]);
2377 identity_files[n_ids] = filename;
2378 identity_keys[n_ids] = public;
2379 identity_file_userprovided[n_ids] =
2380 options.identity_file_userprovided[i];
2381 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2382 continue;
2383
2384 /*
2385 * If no certificates have been explicitly listed then try
2386 * to add the default certificate variant too.
2387 */
2388 if (options.num_certificate_files != 0)
2389 continue;
2390 xasprintf(&cp, "%s-cert", filename);
2391 check_load(sshkey_load_public(cp, &public, NULL),
2392 &public, filename, "pubkey");
2393 debug("identity file %s type %d", cp,
2394 public ? public->type : -1);
2395 if (public == NULL) {
2396 free(cp);
2397 continue;
2398 }
2399 if (!sshkey_is_cert(public)) {
2400 debug_f("key %s type %s is not a certificate",
2401 cp, sshkey_type(public));
2402 sshkey_free(public);
2403 free(cp);
2404 continue;
2405 }
2406 /* NB. leave filename pointing to private key */
2407 identity_files[n_ids] = xstrdup(filename);
2408 identity_keys[n_ids] = public;
2409 identity_file_userprovided[n_ids] =
2410 options.identity_file_userprovided[i];
2411 n_ids++;
2412 }
2413
2414 if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2415 fatal_f("too many certificates");
2416 for (i = 0; i < options.num_certificate_files; i++) {
2417 cp = tilde_expand_filename(options.certificate_files[i],
2418 getuid());
2419 filename = default_client_percent_dollar_expand(cp, cinfo);
2420 free(cp);
2421
2422 check_load(sshkey_load_public(filename, &public, NULL),
2423 &public, filename, "certificate");
2424 debug("certificate file %s type %d", filename,
2425 public ? public->type : -1);
2426 free(options.certificate_files[i]);
2427 options.certificate_files[i] = NULL;
2428 if (public == NULL) {
2429 free(filename);
2430 continue;
2431 }
2432 if (!sshkey_is_cert(public)) {
2433 debug_f("key %s type %s is not a certificate",
2434 filename, sshkey_type(public));
2435 sshkey_free(public);
2436 free(filename);
2437 continue;
2438 }
2439 certificate_files[n_certs] = filename;
2440 certificates[n_certs] = public;
2441 certificate_file_userprovided[n_certs] =
2442 options.certificate_file_userprovided[i];
2443 ++n_certs;
2444 }
2445
2446 options.num_identity_files = n_ids;
2447 memcpy(options.identity_files, identity_files, sizeof(identity_files));
2448 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2449 memcpy(options.identity_file_userprovided,
2450 identity_file_userprovided, sizeof(identity_file_userprovided));
2451
2452 options.num_certificate_files = n_certs;
2453 memcpy(options.certificate_files,
2454 certificate_files, sizeof(certificate_files));
2455 memcpy(options.certificates, certificates, sizeof(certificates));
2456 memcpy(options.certificate_file_userprovided,
2457 certificate_file_userprovided,
2458 sizeof(certificate_file_userprovided));
2459 }
2460
2461 static void
main_sigchld_handler(int sig)2462 main_sigchld_handler(int sig)
2463 {
2464 int save_errno = errno;
2465 pid_t pid;
2466 int status;
2467
2468 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2469 (pid == -1 && errno == EINTR))
2470 ;
2471 errno = save_errno;
2472 }
2473