1 /* $OpenBSD: ssh.c,v 1.569 2021/09/20 04:02:13 dtucker Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * 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 int need_controlpersist_detach = 0;
134
135 /* Copies of flags for ControlPersist foreground mux-client */
136 int ostdin_null_flag, osession_type, otty_flag, orequest_tty;
137
138 /*
139 * General data structure for command line options and options configurable
140 * in configuration files. See readconf.h.
141 */
142 Options options;
143
144 /* optional user configfile */
145 char *config = NULL;
146
147 /*
148 * Name of the host we are connecting to. This is the name given on the
149 * command line, or the Hostname specified for the user-supplied name in a
150 * configuration file.
151 */
152 char *host;
153
154 /*
155 * A config can specify a path to forward, overriding SSH_AUTH_SOCK. If this is
156 * not NULL, forward the socket at this path instead.
157 */
158 char *forward_agent_sock_path = NULL;
159
160 /* socket address the host resolves to */
161 struct sockaddr_storage hostaddr;
162
163 /* Private host keys. */
164 Sensitive sensitive_data;
165
166 /* command to be executed */
167 struct sshbuf *command;
168
169 /* # of replies received for global requests */
170 static int forward_confirms_pending = -1;
171
172 /* mux.c */
173 extern int muxserver_sock;
174 extern u_int muxclient_command;
175
176 /* Prints a help message to the user. This function never returns. */
177
178 static void
usage(void)179 usage(void)
180 {
181 fprintf(stderr,
182 "usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]\n"
183 " [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]\n"
184 " [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]\n"
185 " [-i identity_file] [-J [user@]host[:port]] [-L address]\n"
186 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
187 " [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\n"
188 " [-w local_tun[:remote_tun]] destination [command [argument ...]]\n"
189 );
190 exit(255);
191 }
192
193 static int ssh_session2(struct ssh *, const struct ssh_conn_info *);
194 static void load_public_identity_files(const struct ssh_conn_info *);
195 static void main_sigchld_handler(int);
196
197 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
198 static void
tilde_expand_paths(char ** paths,u_int num_paths)199 tilde_expand_paths(char **paths, u_int num_paths)
200 {
201 u_int i;
202 char *cp;
203
204 for (i = 0; i < num_paths; i++) {
205 cp = tilde_expand_filename(paths[i], getuid());
206 free(paths[i]);
207 paths[i] = cp;
208 }
209 }
210
211 /*
212 * Expands the set of percent_expand options used by the majority of keywords
213 * in the client that support percent expansion.
214 * Caller must free returned string.
215 */
216 static char *
default_client_percent_expand(const char * str,const struct ssh_conn_info * cinfo)217 default_client_percent_expand(const char *str,
218 const struct ssh_conn_info *cinfo)
219 {
220 return percent_expand(str,
221 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
222 (char *)NULL);
223 }
224
225 /*
226 * Expands the set of percent_expand options used by the majority of keywords
227 * AND perform environment variable substitution.
228 * Caller must free returned string.
229 */
230 static char *
default_client_percent_dollar_expand(const char * str,const struct ssh_conn_info * cinfo)231 default_client_percent_dollar_expand(const char *str,
232 const struct ssh_conn_info *cinfo)
233 {
234 char *ret;
235
236 ret = percent_dollar_expand(str,
237 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
238 (char *)NULL);
239 if (ret == NULL)
240 fatal("invalid environment variable expansion");
241 return ret;
242 }
243
244 /*
245 * Attempt to resolve a host name / port to a set of addresses and
246 * optionally return any CNAMEs encountered along the way.
247 * Returns NULL on failure.
248 * NB. this function must operate with a options having undefined members.
249 */
250 static struct addrinfo *
resolve_host(const char * name,int port,int logerr,char * cname,size_t clen)251 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
252 {
253 char strport[NI_MAXSERV];
254 struct addrinfo hints, *res;
255 int gaierr;
256 LogLevel loglevel = SYSLOG_LEVEL_DEBUG1;
257
258 if (port <= 0)
259 port = default_ssh_port();
260 if (cname != NULL)
261 *cname = '\0';
262 debug3_f("lookup %s:%d", name, port);
263
264 snprintf(strport, sizeof strport, "%d", port);
265 memset(&hints, 0, sizeof(hints));
266 hints.ai_family = options.address_family == -1 ?
267 AF_UNSPEC : options.address_family;
268 hints.ai_socktype = SOCK_STREAM;
269 if (cname != NULL)
270 hints.ai_flags = AI_CANONNAME;
271 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
272 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
273 loglevel = SYSLOG_LEVEL_ERROR;
274 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
275 __progname, name, ssh_gai_strerror(gaierr));
276 return NULL;
277 }
278 if (cname != NULL && res->ai_canonname != NULL) {
279 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
280 error_f("host \"%s\" cname \"%s\" too long (max %lu)",
281 name, res->ai_canonname, (u_long)clen);
282 if (clen > 0)
283 *cname = '\0';
284 }
285 }
286 return res;
287 }
288
289 /* Returns non-zero if name can only be an address and not a hostname */
290 static int
is_addr_fast(const char * name)291 is_addr_fast(const char *name)
292 {
293 return (strchr(name, '%') != NULL || strchr(name, ':') != NULL ||
294 strspn(name, "0123456789.") == strlen(name));
295 }
296
297 /* Returns non-zero if name represents a valid, single address */
298 static int
is_addr(const char * name)299 is_addr(const char *name)
300 {
301 char strport[NI_MAXSERV];
302 struct addrinfo hints, *res;
303
304 if (is_addr_fast(name))
305 return 1;
306
307 snprintf(strport, sizeof strport, "%u", default_ssh_port());
308 memset(&hints, 0, sizeof(hints));
309 hints.ai_family = options.address_family == -1 ?
310 AF_UNSPEC : options.address_family;
311 hints.ai_socktype = SOCK_STREAM;
312 hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
313 if (getaddrinfo(name, strport, &hints, &res) != 0)
314 return 0;
315 if (res == NULL || res->ai_next != NULL) {
316 freeaddrinfo(res);
317 return 0;
318 }
319 freeaddrinfo(res);
320 return 1;
321 }
322
323 /*
324 * Attempt to resolve a numeric host address / port to a single address.
325 * Returns a canonical address string.
326 * Returns NULL on failure.
327 * NB. this function must operate with a options having undefined members.
328 */
329 static struct addrinfo *
resolve_addr(const char * name,int port,char * caddr,size_t clen)330 resolve_addr(const char *name, int port, char *caddr, size_t clen)
331 {
332 char addr[NI_MAXHOST], strport[NI_MAXSERV];
333 struct addrinfo hints, *res;
334 int gaierr;
335
336 if (port <= 0)
337 port = default_ssh_port();
338 snprintf(strport, sizeof strport, "%u", port);
339 memset(&hints, 0, sizeof(hints));
340 hints.ai_family = options.address_family == -1 ?
341 AF_UNSPEC : options.address_family;
342 hints.ai_socktype = SOCK_STREAM;
343 hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
344 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
345 debug2_f("could not resolve name %.100s as address: %s",
346 name, ssh_gai_strerror(gaierr));
347 return NULL;
348 }
349 if (res == NULL) {
350 debug_f("getaddrinfo %.100s returned no addresses", name);
351 return NULL;
352 }
353 if (res->ai_next != NULL) {
354 debug_f("getaddrinfo %.100s returned multiple addresses", name);
355 goto fail;
356 }
357 if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
358 addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
359 debug_f("Could not format address for name %.100s: %s",
360 name, ssh_gai_strerror(gaierr));
361 goto fail;
362 }
363 if (strlcpy(caddr, addr, clen) >= clen) {
364 error_f("host \"%s\" addr \"%s\" too long (max %lu)",
365 name, addr, (u_long)clen);
366 if (clen > 0)
367 *caddr = '\0';
368 fail:
369 freeaddrinfo(res);
370 return NULL;
371 }
372 return res;
373 }
374
375 /*
376 * Check whether the cname is a permitted replacement for the hostname
377 * and perform the replacement if it is.
378 * NB. this function must operate with a options having undefined members.
379 */
380 static int
check_follow_cname(int direct,char ** namep,const char * cname)381 check_follow_cname(int direct, char **namep, const char *cname)
382 {
383 int i;
384 struct allowed_cname *rule;
385
386 if (*cname == '\0' || !config_has_permitted_cnames(&options) ||
387 strcmp(*namep, cname) == 0)
388 return 0;
389 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
390 return 0;
391 /*
392 * Don't attempt to canonicalize names that will be interpreted by
393 * a proxy or jump host unless the user specifically requests so.
394 */
395 if (!direct &&
396 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
397 return 0;
398 debug3_f("check \"%s\" CNAME \"%s\"", *namep, cname);
399 for (i = 0; i < options.num_permitted_cnames; i++) {
400 rule = options.permitted_cnames + i;
401 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
402 match_pattern_list(cname, rule->target_list, 1) != 1)
403 continue;
404 verbose("Canonicalized DNS aliased hostname "
405 "\"%s\" => \"%s\"", *namep, cname);
406 free(*namep);
407 *namep = xstrdup(cname);
408 return 1;
409 }
410 return 0;
411 }
412
413 /*
414 * Attempt to resolve the supplied hostname after applying the user's
415 * canonicalization rules. Returns the address list for the host or NULL
416 * if no name was found after canonicalization.
417 * NB. this function must operate with a options having undefined members.
418 */
419 static struct addrinfo *
resolve_canonicalize(char ** hostp,int port)420 resolve_canonicalize(char **hostp, int port)
421 {
422 int i, direct, ndots;
423 char *cp, *fullhost, newname[NI_MAXHOST];
424 struct addrinfo *addrs;
425
426 /*
427 * Attempt to canonicalise addresses, regardless of
428 * whether hostname canonicalisation was requested
429 */
430 if ((addrs = resolve_addr(*hostp, port,
431 newname, sizeof(newname))) != NULL) {
432 debug2_f("hostname %.100s is address", *hostp);
433 if (strcasecmp(*hostp, newname) != 0) {
434 debug2_f("canonicalised address \"%s\" => \"%s\"",
435 *hostp, newname);
436 free(*hostp);
437 *hostp = xstrdup(newname);
438 }
439 return addrs;
440 }
441
442 /*
443 * If this looks like an address but didn't parse as one, it might
444 * be an address with an invalid interface scope. Skip further
445 * attempts at canonicalisation.
446 */
447 if (is_addr_fast(*hostp)) {
448 debug_f("hostname %.100s is an unrecognised address", *hostp);
449 return NULL;
450 }
451
452 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
453 return NULL;
454
455 /*
456 * Don't attempt to canonicalize names that will be interpreted by
457 * a proxy unless the user specifically requests so.
458 */
459 direct = option_clear_or_none(options.proxy_command) &&
460 options.jump_host == NULL;
461 if (!direct &&
462 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
463 return NULL;
464
465 /* If domain name is anchored, then resolve it now */
466 if ((*hostp)[strlen(*hostp) - 1] == '.') {
467 debug3_f("name is fully qualified");
468 fullhost = xstrdup(*hostp);
469 if ((addrs = resolve_host(fullhost, port, 0,
470 newname, sizeof(newname))) != NULL)
471 goto found;
472 free(fullhost);
473 goto notfound;
474 }
475
476 /* Don't apply canonicalization to sufficiently-qualified hostnames */
477 ndots = 0;
478 for (cp = *hostp; *cp != '\0'; cp++) {
479 if (*cp == '.')
480 ndots++;
481 }
482 if (ndots > options.canonicalize_max_dots) {
483 debug3_f("not canonicalizing hostname \"%s\" (max dots %d)",
484 *hostp, options.canonicalize_max_dots);
485 return NULL;
486 }
487 /* Attempt each supplied suffix */
488 for (i = 0; i < options.num_canonical_domains; i++) {
489 if (strcasecmp(options.canonical_domains[i], "none") == 0)
490 break;
491 xasprintf(&fullhost, "%s.%s.", *hostp,
492 options.canonical_domains[i]);
493 debug3_f("attempting \"%s\" => \"%s\"", *hostp, fullhost);
494 if ((addrs = resolve_host(fullhost, port, 0,
495 newname, sizeof(newname))) == NULL) {
496 free(fullhost);
497 continue;
498 }
499 found:
500 /* Remove trailing '.' */
501 fullhost[strlen(fullhost) - 1] = '\0';
502 /* Follow CNAME if requested */
503 if (!check_follow_cname(direct, &fullhost, newname)) {
504 debug("Canonicalized hostname \"%s\" => \"%s\"",
505 *hostp, fullhost);
506 }
507 free(*hostp);
508 *hostp = fullhost;
509 return addrs;
510 }
511 notfound:
512 if (!options.canonicalize_fallback_local)
513 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
514 debug2_f("host %s not found in any suffix", *hostp);
515 return NULL;
516 }
517
518 /*
519 * Check the result of hostkey loading, ignoring some errors and
520 * fatal()ing for others.
521 */
522 static void
check_load(int r,const char * path,const char * message)523 check_load(int r, const char *path, const char *message)
524 {
525 switch (r) {
526 case 0:
527 break;
528 case SSH_ERR_INTERNAL_ERROR:
529 case SSH_ERR_ALLOC_FAIL:
530 fatal_r(r, "load %s \"%s\"", message, path);
531 case SSH_ERR_SYSTEM_ERROR:
532 /* Ignore missing files */
533 if (errno == ENOENT)
534 break;
535 /* FALLTHROUGH */
536 default:
537 error_r(r, "load %s \"%s\"", message, path);
538 break;
539 }
540 }
541
542 /*
543 * Read per-user configuration file. Ignore the system wide config
544 * file if the user specifies a config file on the command line.
545 */
546 static void
process_config_files(const char * host_name,struct passwd * pw,int final_pass,int * want_final_pass)547 process_config_files(const char *host_name, struct passwd *pw, int final_pass,
548 int *want_final_pass)
549 {
550 char buf[PATH_MAX];
551 int r;
552
553 if (config != NULL) {
554 if (strcasecmp(config, "none") != 0 &&
555 !read_config_file(config, pw, host, host_name, &options,
556 SSHCONF_USERCONF | (final_pass ? SSHCONF_FINAL : 0),
557 want_final_pass))
558 fatal("Can't open user config file %.100s: "
559 "%.100s", config, strerror(errno));
560 } else {
561 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
562 _PATH_SSH_USER_CONFFILE);
563 if (r > 0 && (size_t)r < sizeof(buf))
564 (void)read_config_file(buf, pw, host, host_name,
565 &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
566 (final_pass ? SSHCONF_FINAL : 0), want_final_pass);
567
568 /* Read systemwide configuration file after user config. */
569 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
570 host, host_name, &options,
571 final_pass ? SSHCONF_FINAL : 0, want_final_pass);
572 }
573 }
574
575 /* Rewrite the port number in an addrinfo list of addresses */
576 static void
set_addrinfo_port(struct addrinfo * addrs,int port)577 set_addrinfo_port(struct addrinfo *addrs, int port)
578 {
579 struct addrinfo *addr;
580
581 for (addr = addrs; addr != NULL; addr = addr->ai_next) {
582 switch (addr->ai_family) {
583 case AF_INET:
584 ((struct sockaddr_in *)addr->ai_addr)->
585 sin_port = htons(port);
586 break;
587 case AF_INET6:
588 ((struct sockaddr_in6 *)addr->ai_addr)->
589 sin6_port = htons(port);
590 break;
591 }
592 }
593 }
594
595 static void
ssh_conn_info_free(struct ssh_conn_info * cinfo)596 ssh_conn_info_free(struct ssh_conn_info *cinfo)
597 {
598 if (cinfo == NULL)
599 return;
600 free(cinfo->conn_hash_hex);
601 free(cinfo->shorthost);
602 free(cinfo->uidstr);
603 free(cinfo->keyalias);
604 free(cinfo->thishost);
605 free(cinfo->host_arg);
606 free(cinfo->portstr);
607 free(cinfo->remhost);
608 free(cinfo->remuser);
609 free(cinfo->homedir);
610 free(cinfo->locuser);
611 free(cinfo);
612 }
613
614 /*
615 * Main program for the ssh client.
616 */
617 int
main(int ac,char ** av)618 main(int ac, char **av)
619 {
620 struct ssh *ssh = NULL;
621 int i, r, opt, exit_status, use_syslog, direct, timeout_ms;
622 int was_addr, config_test = 0, opt_terminated = 0, want_final_pass = 0;
623 char *p, *cp, *line, *argv0, *logfile, *host_arg;
624 char cname[NI_MAXHOST], thishost[NI_MAXHOST];
625 struct stat st;
626 struct passwd *pw;
627 extern int optind, optreset;
628 extern char *optarg;
629 struct Forward fwd;
630 struct addrinfo *addrs = NULL;
631 size_t n, len;
632 u_int j;
633 struct ssh_conn_info *cinfo = NULL;
634
635 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
636 sanitise_stdfd();
637
638 /*
639 * Discard other fds that are hanging around. These can cause problem
640 * with backgrounded ssh processes started by ControlPersist.
641 */
642 closefrom(STDERR_FILENO + 1);
643
644 __progname = ssh_get_progname(av[0]);
645
646 #ifndef HAVE_SETPROCTITLE
647 /* Prepare for later setproctitle emulation */
648 /* Save argv so it isn't clobbered by setproctitle() emulation */
649 saved_av = xcalloc(ac + 1, sizeof(*saved_av));
650 for (i = 0; i < ac; i++)
651 saved_av[i] = xstrdup(av[i]);
652 saved_av[i] = NULL;
653 compat_init_setproctitle(ac, av);
654 av = saved_av;
655 #endif
656
657 seed_rng();
658
659 /* Get user data. */
660 pw = getpwuid(getuid());
661 if (!pw) {
662 logit("No user exists for uid %lu", (u_long)getuid());
663 exit(255);
664 }
665 /* Take a copy of the returned structure. */
666 pw = pwcopy(pw);
667
668 /*
669 * Set our umask to something reasonable, as some files are created
670 * with the default umask. This will make them world-readable but
671 * writable only by the owner, which is ok for all files for which we
672 * don't set the modes explicitly.
673 */
674 umask(022);
675
676 msetlocale();
677
678 /*
679 * Initialize option structure to indicate that no values have been
680 * set.
681 */
682 initialize_options(&options);
683
684 /*
685 * Prepare main ssh transport/connection structures
686 */
687 if ((ssh = ssh_alloc_session_state()) == NULL)
688 fatal("Couldn't allocate session state");
689 channel_init_channels(ssh);
690
691 /* Parse command-line arguments. */
692 host = NULL;
693 use_syslog = 0;
694 logfile = NULL;
695 argv0 = av[0];
696
697 again:
698 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
699 "AB:CD:E:F:GI:J:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
700 switch (opt) {
701 case '1':
702 fatal("SSH protocol v.1 is no longer supported");
703 break;
704 case '2':
705 /* Ignored */
706 break;
707 case '4':
708 options.address_family = AF_INET;
709 break;
710 case '6':
711 options.address_family = AF_INET6;
712 break;
713 case 'n':
714 options.stdin_null = 1;
715 break;
716 case 'f':
717 options.fork_after_authentication = 1;
718 options.stdin_null = 1;
719 break;
720 case 'x':
721 options.forward_x11 = 0;
722 break;
723 case 'X':
724 options.forward_x11 = 1;
725 break;
726 case 'y':
727 use_syslog = 1;
728 break;
729 case 'E':
730 logfile = optarg;
731 break;
732 case 'G':
733 config_test = 1;
734 break;
735 case 'Y':
736 options.forward_x11 = 1;
737 options.forward_x11_trusted = 1;
738 break;
739 case 'g':
740 options.fwd_opts.gateway_ports = 1;
741 break;
742 case 'O':
743 if (options.stdio_forward_host != NULL)
744 fatal("Cannot specify multiplexing "
745 "command with -W");
746 else if (muxclient_command != 0)
747 fatal("Multiplexing command already specified");
748 if (strcmp(optarg, "check") == 0)
749 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
750 else if (strcmp(optarg, "forward") == 0)
751 muxclient_command = SSHMUX_COMMAND_FORWARD;
752 else if (strcmp(optarg, "exit") == 0)
753 muxclient_command = SSHMUX_COMMAND_TERMINATE;
754 else if (strcmp(optarg, "stop") == 0)
755 muxclient_command = SSHMUX_COMMAND_STOP;
756 else if (strcmp(optarg, "cancel") == 0)
757 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
758 else if (strcmp(optarg, "proxy") == 0)
759 muxclient_command = SSHMUX_COMMAND_PROXY;
760 else
761 fatal("Invalid multiplex command.");
762 break;
763 case 'P': /* deprecated */
764 break;
765 case 'Q':
766 cp = NULL;
767 if (strcmp(optarg, "cipher") == 0 ||
768 strcasecmp(optarg, "Ciphers") == 0)
769 cp = cipher_alg_list('\n', 0);
770 else if (strcmp(optarg, "cipher-auth") == 0)
771 cp = cipher_alg_list('\n', 1);
772 else if (strcmp(optarg, "mac") == 0 ||
773 strcasecmp(optarg, "MACs") == 0)
774 cp = mac_alg_list('\n');
775 else if (strcmp(optarg, "kex") == 0 ||
776 strcasecmp(optarg, "KexAlgorithms") == 0)
777 cp = kex_alg_list('\n');
778 else if (strcmp(optarg, "key") == 0)
779 cp = sshkey_alg_list(0, 0, 0, '\n');
780 else if (strcmp(optarg, "key-cert") == 0)
781 cp = sshkey_alg_list(1, 0, 0, '\n');
782 else if (strcmp(optarg, "key-plain") == 0)
783 cp = sshkey_alg_list(0, 1, 0, '\n');
784 else if (strcmp(optarg, "key-sig") == 0 ||
785 strcasecmp(optarg, "PubkeyAcceptedKeyTypes") == 0 || /* deprecated name */
786 strcasecmp(optarg, "PubkeyAcceptedAlgorithms") == 0 ||
787 strcasecmp(optarg, "HostKeyAlgorithms") == 0 ||
788 strcasecmp(optarg, "HostbasedKeyTypes") == 0 || /* deprecated name */
789 strcasecmp(optarg, "HostbasedAcceptedKeyTypes") == 0 || /* deprecated name */
790 strcasecmp(optarg, "HostbasedAcceptedAlgorithms") == 0)
791 cp = sshkey_alg_list(0, 0, 1, '\n');
792 else if (strcmp(optarg, "sig") == 0)
793 cp = sshkey_alg_list(0, 1, 1, '\n');
794 else if (strcmp(optarg, "protocol-version") == 0)
795 cp = xstrdup("2");
796 else if (strcmp(optarg, "compression") == 0) {
797 cp = xstrdup(compression_alg_list(0));
798 len = strlen(cp);
799 for (n = 0; n < len; n++)
800 if (cp[n] == ',')
801 cp[n] = '\n';
802 } else if (strcmp(optarg, "help") == 0) {
803 cp = xstrdup(
804 "cipher\ncipher-auth\ncompression\nkex\n"
805 "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
806 "protocol-version\nsig");
807 }
808 if (cp == NULL)
809 fatal("Unsupported query \"%s\"", optarg);
810 printf("%s\n", cp);
811 free(cp);
812 exit(0);
813 break;
814 case 'a':
815 options.forward_agent = 0;
816 break;
817 case 'A':
818 options.forward_agent = 1;
819 break;
820 case 'k':
821 options.gss_deleg_creds = 0;
822 break;
823 case 'K':
824 options.gss_authentication = 1;
825 options.gss_deleg_creds = 1;
826 break;
827 case 'i':
828 p = tilde_expand_filename(optarg, getuid());
829 if (stat(p, &st) == -1)
830 fprintf(stderr, "Warning: Identity file %s "
831 "not accessible: %s.\n", p,
832 strerror(errno));
833 else
834 add_identity_file(&options, NULL, p, 1);
835 free(p);
836 break;
837 case 'I':
838 #ifdef ENABLE_PKCS11
839 free(options.pkcs11_provider);
840 options.pkcs11_provider = xstrdup(optarg);
841 #else
842 fprintf(stderr, "no support for PKCS#11.\n");
843 #endif
844 break;
845 case 'J':
846 if (options.jump_host != NULL) {
847 fatal("Only a single -J option is permitted "
848 "(use commas to separate multiple "
849 "jump hops)");
850 }
851 if (options.proxy_command != NULL)
852 fatal("Cannot specify -J with ProxyCommand");
853 if (parse_jump(optarg, &options, 1) == -1)
854 fatal("Invalid -J argument");
855 options.proxy_command = xstrdup("none");
856 break;
857 case 't':
858 if (options.request_tty == REQUEST_TTY_YES)
859 options.request_tty = REQUEST_TTY_FORCE;
860 else
861 options.request_tty = REQUEST_TTY_YES;
862 break;
863 case 'v':
864 if (debug_flag == 0) {
865 debug_flag = 1;
866 options.log_level = SYSLOG_LEVEL_DEBUG1;
867 } else {
868 if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
869 debug_flag++;
870 options.log_level++;
871 }
872 }
873 break;
874 case 'V':
875 fprintf(stderr, "%s, %s\n",
876 SSH_RELEASE, SSH_OPENSSL_VERSION);
877 if (opt == 'V')
878 exit(0);
879 break;
880 case 'w':
881 if (options.tun_open == -1)
882 options.tun_open = SSH_TUNMODE_DEFAULT;
883 options.tun_local = a2tun(optarg, &options.tun_remote);
884 if (options.tun_local == SSH_TUNID_ERR) {
885 fprintf(stderr,
886 "Bad tun device '%s'\n", optarg);
887 exit(255);
888 }
889 break;
890 case 'W':
891 if (options.stdio_forward_host != NULL)
892 fatal("stdio forward already specified");
893 if (muxclient_command != 0)
894 fatal("Cannot specify stdio forward with -O");
895 if (parse_forward(&fwd, optarg, 1, 0)) {
896 options.stdio_forward_host = fwd.listen_host;
897 options.stdio_forward_port = fwd.listen_port;
898 free(fwd.connect_host);
899 } else {
900 fprintf(stderr,
901 "Bad stdio forwarding specification '%s'\n",
902 optarg);
903 exit(255);
904 }
905 options.request_tty = REQUEST_TTY_NO;
906 options.session_type = SESSION_TYPE_NONE;
907 break;
908 case 'q':
909 options.log_level = SYSLOG_LEVEL_QUIET;
910 break;
911 case 'e':
912 if (optarg[0] == '^' && optarg[2] == 0 &&
913 (u_char) optarg[1] >= 64 &&
914 (u_char) optarg[1] < 128)
915 options.escape_char = (u_char) optarg[1] & 31;
916 else if (strlen(optarg) == 1)
917 options.escape_char = (u_char) optarg[0];
918 else if (strcmp(optarg, "none") == 0)
919 options.escape_char = SSH_ESCAPECHAR_NONE;
920 else {
921 fprintf(stderr, "Bad escape character '%s'.\n",
922 optarg);
923 exit(255);
924 }
925 break;
926 case 'c':
927 if (!ciphers_valid(*optarg == '+' || *optarg == '^' ?
928 optarg + 1 : optarg)) {
929 fprintf(stderr, "Unknown cipher type '%s'\n",
930 optarg);
931 exit(255);
932 }
933 free(options.ciphers);
934 options.ciphers = xstrdup(optarg);
935 break;
936 case 'm':
937 if (mac_valid(optarg)) {
938 free(options.macs);
939 options.macs = xstrdup(optarg);
940 } else {
941 fprintf(stderr, "Unknown mac type '%s'\n",
942 optarg);
943 exit(255);
944 }
945 break;
946 case 'M':
947 if (options.control_master == SSHCTL_MASTER_YES)
948 options.control_master = SSHCTL_MASTER_ASK;
949 else
950 options.control_master = SSHCTL_MASTER_YES;
951 break;
952 case 'p':
953 if (options.port == -1) {
954 options.port = a2port(optarg);
955 if (options.port <= 0) {
956 fprintf(stderr, "Bad port '%s'\n",
957 optarg);
958 exit(255);
959 }
960 }
961 break;
962 case 'l':
963 if (options.user == NULL)
964 options.user = optarg;
965 break;
966
967 case 'L':
968 if (parse_forward(&fwd, optarg, 0, 0))
969 add_local_forward(&options, &fwd);
970 else {
971 fprintf(stderr,
972 "Bad local forwarding specification '%s'\n",
973 optarg);
974 exit(255);
975 }
976 break;
977
978 case 'R':
979 if (parse_forward(&fwd, optarg, 0, 1) ||
980 parse_forward(&fwd, optarg, 1, 1)) {
981 add_remote_forward(&options, &fwd);
982 } else {
983 fprintf(stderr,
984 "Bad remote forwarding specification "
985 "'%s'\n", optarg);
986 exit(255);
987 }
988 break;
989
990 case 'D':
991 if (parse_forward(&fwd, optarg, 1, 0)) {
992 add_local_forward(&options, &fwd);
993 } else {
994 fprintf(stderr,
995 "Bad dynamic forwarding specification "
996 "'%s'\n", optarg);
997 exit(255);
998 }
999 break;
1000
1001 case 'C':
1002 #ifdef WITH_ZLIB
1003 options.compression = 1;
1004 #else
1005 error("Compression not supported, disabling.");
1006 #endif
1007 break;
1008 case 'N':
1009 if (options.session_type != -1 &&
1010 options.session_type != SESSION_TYPE_NONE)
1011 fatal("Cannot specify -N with -s/SessionType");
1012 options.session_type = SESSION_TYPE_NONE;
1013 options.request_tty = REQUEST_TTY_NO;
1014 break;
1015 case 'T':
1016 options.request_tty = REQUEST_TTY_NO;
1017 break;
1018 case 'o':
1019 line = xstrdup(optarg);
1020 if (process_config_line(&options, pw,
1021 host ? host : "", host ? host : "", line,
1022 "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
1023 exit(255);
1024 free(line);
1025 break;
1026 case 's':
1027 if (options.session_type != -1 &&
1028 options.session_type != SESSION_TYPE_SUBSYSTEM)
1029 fatal("Cannot specify -s with -N/SessionType");
1030 options.session_type = SESSION_TYPE_SUBSYSTEM;
1031 break;
1032 case 'S':
1033 free(options.control_path);
1034 options.control_path = xstrdup(optarg);
1035 break;
1036 case 'b':
1037 options.bind_address = optarg;
1038 break;
1039 case 'B':
1040 options.bind_interface = optarg;
1041 break;
1042 case 'F':
1043 config = optarg;
1044 break;
1045 default:
1046 usage();
1047 }
1048 }
1049
1050 if (optind > 1 && strcmp(av[optind - 1], "--") == 0)
1051 opt_terminated = 1;
1052
1053 ac -= optind;
1054 av += optind;
1055
1056 if (ac > 0 && !host) {
1057 int tport;
1058 char *tuser;
1059 switch (parse_ssh_uri(*av, &tuser, &host, &tport)) {
1060 case -1:
1061 usage();
1062 break;
1063 case 0:
1064 if (options.user == NULL) {
1065 options.user = tuser;
1066 tuser = NULL;
1067 }
1068 free(tuser);
1069 if (options.port == -1 && tport != -1)
1070 options.port = tport;
1071 break;
1072 default:
1073 p = xstrdup(*av);
1074 cp = strrchr(p, '@');
1075 if (cp != NULL) {
1076 if (cp == p)
1077 usage();
1078 if (options.user == NULL) {
1079 options.user = p;
1080 p = NULL;
1081 }
1082 *cp++ = '\0';
1083 host = xstrdup(cp);
1084 free(p);
1085 } else
1086 host = p;
1087 break;
1088 }
1089 if (ac > 1 && !opt_terminated) {
1090 optind = optreset = 1;
1091 goto again;
1092 }
1093 ac--, av++;
1094 }
1095
1096 /* Check that we got a host name. */
1097 if (!host)
1098 usage();
1099
1100 host_arg = xstrdup(host);
1101
1102 /* Initialize the command to execute on remote host. */
1103 if ((command = sshbuf_new()) == NULL)
1104 fatal("sshbuf_new failed");
1105
1106 /*
1107 * Save the command to execute on the remote host in a buffer. There
1108 * is no limit on the length of the command, except by the maximum
1109 * packet size. Also sets the tty flag if there is no command.
1110 */
1111 if (!ac) {
1112 /* No command specified - execute shell on a tty. */
1113 if (options.session_type == SESSION_TYPE_SUBSYSTEM) {
1114 fprintf(stderr,
1115 "You must specify a subsystem to invoke.\n");
1116 usage();
1117 }
1118 } else {
1119 /* A command has been specified. Store it into the buffer. */
1120 for (i = 0; i < ac; i++) {
1121 if ((r = sshbuf_putf(command, "%s%s",
1122 i ? " " : "", av[i])) != 0)
1123 fatal_fr(r, "buffer error");
1124 }
1125 }
1126
1127 /*
1128 * Initialize "log" output. Since we are the client all output
1129 * goes to stderr unless otherwise specified by -y or -E.
1130 */
1131 if (use_syslog && logfile != NULL)
1132 fatal("Can't specify both -y and -E");
1133 if (logfile != NULL)
1134 log_redirect_stderr_to(logfile);
1135 log_init(argv0,
1136 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1137 SYSLOG_LEVEL_INFO : options.log_level,
1138 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1139 SYSLOG_FACILITY_USER : options.log_facility,
1140 !use_syslog);
1141
1142 if (debug_flag)
1143 logit("%s, %s", SSH_RELEASE, SSH_OPENSSL_VERSION);
1144
1145 /* Parse the configuration files */
1146 process_config_files(host_arg, pw, 0, &want_final_pass);
1147 if (want_final_pass)
1148 debug("configuration requests final Match pass");
1149
1150 /* Hostname canonicalisation needs a few options filled. */
1151 fill_default_options_for_canonicalization(&options);
1152
1153 /* If the user has replaced the hostname then take it into use now */
1154 if (options.hostname != NULL) {
1155 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1156 cp = percent_expand(options.hostname,
1157 "h", host, (char *)NULL);
1158 free(host);
1159 host = cp;
1160 free(options.hostname);
1161 options.hostname = xstrdup(host);
1162 }
1163
1164 /* Don't lowercase addresses, they will be explicitly canonicalised */
1165 if ((was_addr = is_addr(host)) == 0)
1166 lowercase(host);
1167
1168 /*
1169 * Try to canonicalize if requested by configuration or the
1170 * hostname is an address.
1171 */
1172 if (options.canonicalize_hostname != SSH_CANONICALISE_NO || was_addr)
1173 addrs = resolve_canonicalize(&host, options.port);
1174
1175 /*
1176 * If CanonicalizePermittedCNAMEs have been specified but
1177 * other canonicalization did not happen (by not being requested
1178 * or by failing with fallback) then the hostname may still be changed
1179 * as a result of CNAME following.
1180 *
1181 * Try to resolve the bare hostname name using the system resolver's
1182 * usual search rules and then apply the CNAME follow rules.
1183 *
1184 * Skip the lookup if a ProxyCommand is being used unless the user
1185 * has specifically requested canonicalisation for this case via
1186 * CanonicalizeHostname=always
1187 */
1188 direct = option_clear_or_none(options.proxy_command) &&
1189 options.jump_host == NULL;
1190 if (addrs == NULL && config_has_permitted_cnames(&options) && (direct ||
1191 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1192 if ((addrs = resolve_host(host, options.port,
1193 direct, cname, sizeof(cname))) == NULL) {
1194 /* Don't fatal proxied host names not in the DNS */
1195 if (direct)
1196 cleanup_exit(255); /* logged in resolve_host */
1197 } else
1198 check_follow_cname(direct, &host, cname);
1199 }
1200
1201 /*
1202 * If canonicalisation is enabled then re-parse the configuration
1203 * files as new stanzas may match.
1204 */
1205 if (options.canonicalize_hostname != 0 && !want_final_pass) {
1206 debug("hostname canonicalisation enabled, "
1207 "will re-parse configuration");
1208 want_final_pass = 1;
1209 }
1210
1211 if (want_final_pass) {
1212 debug("re-parsing configuration");
1213 free(options.hostname);
1214 options.hostname = xstrdup(host);
1215 process_config_files(host_arg, pw, 1, NULL);
1216 /*
1217 * Address resolution happens early with canonicalisation
1218 * enabled and the port number may have changed since, so
1219 * reset it in address list
1220 */
1221 if (addrs != NULL && options.port > 0)
1222 set_addrinfo_port(addrs, options.port);
1223 }
1224
1225 /* Fill configuration defaults. */
1226 if (fill_default_options(&options) != 0)
1227 cleanup_exit(255);
1228
1229 if (options.user == NULL)
1230 options.user = xstrdup(pw->pw_name);
1231
1232 /* Find canonic host name. */
1233 if (strchr(host, '.') == 0) {
1234 struct addrinfo hints;
1235 struct addrinfo *ai = NULL;
1236 int errgai;
1237 memset(&hints, 0, sizeof(hints));
1238 hints.ai_family = options.address_family;
1239 hints.ai_flags = AI_CANONNAME;
1240 hints.ai_socktype = SOCK_STREAM;
1241 errgai = getaddrinfo(host, NULL, &hints, &ai);
1242 if (errgai == 0) {
1243 if (ai->ai_canonname != NULL)
1244 host = xstrdup(ai->ai_canonname);
1245 freeaddrinfo(ai);
1246 }
1247 }
1248
1249 /*
1250 * If ProxyJump option specified, then construct a ProxyCommand now.
1251 */
1252 if (options.jump_host != NULL) {
1253 char port_s[8];
1254 const char *jumpuser = options.jump_user, *sshbin = argv0;
1255 int port = options.port, jumpport = options.jump_port;
1256
1257 if (port <= 0)
1258 port = default_ssh_port();
1259 if (jumpport <= 0)
1260 jumpport = default_ssh_port();
1261 if (jumpuser == NULL)
1262 jumpuser = options.user;
1263 if (strcmp(options.jump_host, host) == 0 && port == jumpport &&
1264 strcmp(options.user, jumpuser) == 0)
1265 fatal("jumphost loop via %s", options.jump_host);
1266
1267 /*
1268 * Try to use SSH indicated by argv[0], but fall back to
1269 * "ssh" if it appears unavailable.
1270 */
1271 if (strchr(argv0, '/') != NULL && access(argv0, X_OK) != 0)
1272 sshbin = "ssh";
1273
1274 /* Consistency check */
1275 if (options.proxy_command != NULL)
1276 fatal("inconsistent options: ProxyCommand+ProxyJump");
1277 /* Never use FD passing for ProxyJump */
1278 options.proxy_use_fdpass = 0;
1279 snprintf(port_s, sizeof(port_s), "%d", options.jump_port);
1280 xasprintf(&options.proxy_command,
1281 "%s%s%s%s%s%s%s%s%s%s%.*s -W '[%%h]:%%p' %s",
1282 sshbin,
1283 /* Optional "-l user" argument if jump_user set */
1284 options.jump_user == NULL ? "" : " -l ",
1285 options.jump_user == NULL ? "" : options.jump_user,
1286 /* Optional "-p port" argument if jump_port set */
1287 options.jump_port <= 0 ? "" : " -p ",
1288 options.jump_port <= 0 ? "" : port_s,
1289 /* Optional additional jump hosts ",..." */
1290 options.jump_extra == NULL ? "" : " -J ",
1291 options.jump_extra == NULL ? "" : options.jump_extra,
1292 /* Optional "-F" argumment if -F specified */
1293 config == NULL ? "" : " -F ",
1294 config == NULL ? "" : config,
1295 /* Optional "-v" arguments if -v set */
1296 debug_flag ? " -" : "",
1297 debug_flag, "vvv",
1298 /* Mandatory hostname */
1299 options.jump_host);
1300 debug("Setting implicit ProxyCommand from ProxyJump: %s",
1301 options.proxy_command);
1302 }
1303
1304 if (options.port == 0)
1305 options.port = default_ssh_port();
1306 channel_set_af(ssh, options.address_family);
1307
1308 /* Tidy and check options */
1309 if (options.host_key_alias != NULL)
1310 lowercase(options.host_key_alias);
1311 if (options.proxy_command != NULL &&
1312 strcmp(options.proxy_command, "-") == 0 &&
1313 options.proxy_use_fdpass)
1314 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1315 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1316 if (options.control_persist && options.control_path != NULL) {
1317 debug("UpdateHostKeys=ask is incompatible with "
1318 "ControlPersist; disabling");
1319 options.update_hostkeys = 0;
1320 } else if (sshbuf_len(command) != 0 ||
1321 options.remote_command != NULL ||
1322 options.request_tty == REQUEST_TTY_NO) {
1323 debug("UpdateHostKeys=ask is incompatible with "
1324 "remote command execution; disabling");
1325 options.update_hostkeys = 0;
1326 } else if (options.log_level < SYSLOG_LEVEL_INFO) {
1327 /* no point logging anything; user won't see it */
1328 options.update_hostkeys = 0;
1329 }
1330 }
1331 if (options.connection_attempts <= 0)
1332 fatal("Invalid number of ConnectionAttempts");
1333
1334 if (sshbuf_len(command) != 0 && options.remote_command != NULL)
1335 fatal("Cannot execute command-line and remote command.");
1336
1337 /* Cannot fork to background if no command. */
1338 if (options.fork_after_authentication && sshbuf_len(command) == 0 &&
1339 options.remote_command == NULL &&
1340 options.session_type != SESSION_TYPE_NONE)
1341 fatal("Cannot fork into background without a command "
1342 "to execute.");
1343
1344 /* reinit */
1345 log_init(argv0, options.log_level, options.log_facility, !use_syslog);
1346 for (j = 0; j < options.num_log_verbose; j++) {
1347 if (strcasecmp(options.log_verbose[j], "none") == 0)
1348 break;
1349 log_verbose_add(options.log_verbose[j]);
1350 }
1351
1352 if (options.request_tty == REQUEST_TTY_YES ||
1353 options.request_tty == REQUEST_TTY_FORCE)
1354 tty_flag = 1;
1355
1356 /* Allocate a tty by default if no command specified. */
1357 if (sshbuf_len(command) == 0 && options.remote_command == NULL)
1358 tty_flag = options.request_tty != REQUEST_TTY_NO;
1359
1360 /* Force no tty */
1361 if (options.request_tty == REQUEST_TTY_NO ||
1362 (muxclient_command && muxclient_command != SSHMUX_COMMAND_PROXY))
1363 tty_flag = 0;
1364 /* Do not allocate a tty if stdin is not a tty. */
1365 if ((!isatty(fileno(stdin)) || options.stdin_null) &&
1366 options.request_tty != REQUEST_TTY_FORCE) {
1367 if (tty_flag)
1368 logit("Pseudo-terminal will not be allocated because "
1369 "stdin is not a terminal.");
1370 tty_flag = 0;
1371 }
1372
1373 /* Set up strings used to percent_expand() arguments */
1374 cinfo = xcalloc(1, sizeof(*cinfo));
1375 if (gethostname(thishost, sizeof(thishost)) == -1)
1376 fatal("gethostname: %s", strerror(errno));
1377 cinfo->thishost = xstrdup(thishost);
1378 thishost[strcspn(thishost, ".")] = '\0';
1379 cinfo->shorthost = xstrdup(thishost);
1380 xasprintf(&cinfo->portstr, "%d", options.port);
1381 xasprintf(&cinfo->uidstr, "%llu",
1382 (unsigned long long)pw->pw_uid);
1383 cinfo->keyalias = xstrdup(options.host_key_alias ?
1384 options.host_key_alias : host_arg);
1385 cinfo->conn_hash_hex = ssh_connection_hash(cinfo->thishost, host,
1386 cinfo->portstr, options.user);
1387 cinfo->host_arg = xstrdup(host_arg);
1388 cinfo->remhost = xstrdup(host);
1389 cinfo->remuser = xstrdup(options.user);
1390 cinfo->homedir = xstrdup(pw->pw_dir);
1391 cinfo->locuser = xstrdup(pw->pw_name);
1392
1393 /*
1394 * Expand tokens in arguments. NB. LocalCommand is expanded later,
1395 * after port-forwarding is set up, so it may pick up any local
1396 * tunnel interface name allocated.
1397 */
1398 if (options.remote_command != NULL) {
1399 debug3("expanding RemoteCommand: %s", options.remote_command);
1400 cp = options.remote_command;
1401 options.remote_command = default_client_percent_expand(cp,
1402 cinfo);
1403 debug3("expanded RemoteCommand: %s", options.remote_command);
1404 free(cp);
1405 if ((r = sshbuf_put(command, options.remote_command,
1406 strlen(options.remote_command))) != 0)
1407 fatal_fr(r, "buffer error");
1408 }
1409
1410 if (options.control_path != NULL) {
1411 cp = tilde_expand_filename(options.control_path, getuid());
1412 free(options.control_path);
1413 options.control_path = default_client_percent_dollar_expand(cp,
1414 cinfo);
1415 free(cp);
1416 }
1417
1418 if (options.identity_agent != NULL) {
1419 p = tilde_expand_filename(options.identity_agent, getuid());
1420 cp = default_client_percent_dollar_expand(p, cinfo);
1421 free(p);
1422 free(options.identity_agent);
1423 options.identity_agent = cp;
1424 }
1425
1426 if (options.forward_agent_sock_path != NULL) {
1427 p = tilde_expand_filename(options.forward_agent_sock_path,
1428 getuid());
1429 cp = default_client_percent_dollar_expand(p, cinfo);
1430 free(p);
1431 free(options.forward_agent_sock_path);
1432 options.forward_agent_sock_path = cp;
1433 if (stat(options.forward_agent_sock_path, &st) != 0) {
1434 error("Cannot forward agent socket path \"%s\": %s",
1435 options.forward_agent_sock_path, strerror(errno));
1436 if (options.exit_on_forward_failure)
1437 cleanup_exit(255);
1438 }
1439 }
1440
1441 if (options.num_system_hostfiles > 0 &&
1442 strcasecmp(options.system_hostfiles[0], "none") == 0) {
1443 if (options.num_system_hostfiles > 1)
1444 fatal("Invalid GlobalKnownHostsFiles: \"none\" "
1445 "appears with other entries");
1446 free(options.system_hostfiles[0]);
1447 options.system_hostfiles[0] = NULL;
1448 options.num_system_hostfiles = 0;
1449 }
1450
1451 if (options.num_user_hostfiles > 0 &&
1452 strcasecmp(options.user_hostfiles[0], "none") == 0) {
1453 if (options.num_user_hostfiles > 1)
1454 fatal("Invalid UserKnownHostsFiles: \"none\" "
1455 "appears with other entries");
1456 free(options.user_hostfiles[0]);
1457 options.user_hostfiles[0] = NULL;
1458 options.num_user_hostfiles = 0;
1459 }
1460 for (j = 0; j < options.num_user_hostfiles; j++) {
1461 if (options.user_hostfiles[j] == NULL)
1462 continue;
1463 cp = tilde_expand_filename(options.user_hostfiles[j], getuid());
1464 p = default_client_percent_dollar_expand(cp, cinfo);
1465 if (strcmp(options.user_hostfiles[j], p) != 0)
1466 debug3("expanded UserKnownHostsFile '%s' -> "
1467 "'%s'", options.user_hostfiles[j], p);
1468 free(options.user_hostfiles[j]);
1469 free(cp);
1470 options.user_hostfiles[j] = p;
1471 }
1472
1473 for (i = 0; i < options.num_local_forwards; i++) {
1474 if (options.local_forwards[i].listen_path != NULL) {
1475 cp = options.local_forwards[i].listen_path;
1476 p = options.local_forwards[i].listen_path =
1477 default_client_percent_expand(cp, cinfo);
1478 if (strcmp(cp, p) != 0)
1479 debug3("expanded LocalForward listen path "
1480 "'%s' -> '%s'", cp, p);
1481 free(cp);
1482 }
1483 if (options.local_forwards[i].connect_path != NULL) {
1484 cp = options.local_forwards[i].connect_path;
1485 p = options.local_forwards[i].connect_path =
1486 default_client_percent_expand(cp, cinfo);
1487 if (strcmp(cp, p) != 0)
1488 debug3("expanded LocalForward connect path "
1489 "'%s' -> '%s'", cp, p);
1490 free(cp);
1491 }
1492 }
1493
1494 for (i = 0; i < options.num_remote_forwards; i++) {
1495 if (options.remote_forwards[i].listen_path != NULL) {
1496 cp = options.remote_forwards[i].listen_path;
1497 p = options.remote_forwards[i].listen_path =
1498 default_client_percent_expand(cp, cinfo);
1499 if (strcmp(cp, p) != 0)
1500 debug3("expanded RemoteForward listen path "
1501 "'%s' -> '%s'", cp, p);
1502 free(cp);
1503 }
1504 if (options.remote_forwards[i].connect_path != NULL) {
1505 cp = options.remote_forwards[i].connect_path;
1506 p = options.remote_forwards[i].connect_path =
1507 default_client_percent_expand(cp, cinfo);
1508 if (strcmp(cp, p) != 0)
1509 debug3("expanded RemoteForward connect path "
1510 "'%s' -> '%s'", cp, p);
1511 free(cp);
1512 }
1513 }
1514
1515 if (config_test) {
1516 dump_client_config(&options, host);
1517 exit(0);
1518 }
1519
1520 /* Expand SecurityKeyProvider if it refers to an environment variable */
1521 if (options.sk_provider != NULL && *options.sk_provider == '$' &&
1522 strlen(options.sk_provider) > 1) {
1523 if ((cp = getenv(options.sk_provider + 1)) == NULL) {
1524 debug("Authenticator provider %s did not resolve; "
1525 "disabling", options.sk_provider);
1526 free(options.sk_provider);
1527 options.sk_provider = NULL;
1528 } else {
1529 debug2("resolved SecurityKeyProvider %s => %s",
1530 options.sk_provider, cp);
1531 free(options.sk_provider);
1532 options.sk_provider = xstrdup(cp);
1533 }
1534 }
1535
1536 if (muxclient_command != 0 && options.control_path == NULL)
1537 fatal("No ControlPath specified for \"-O\" command");
1538 if (options.control_path != NULL) {
1539 int sock;
1540 if ((sock = muxclient(options.control_path)) >= 0) {
1541 ssh_packet_set_connection(ssh, sock, sock);
1542 ssh_packet_set_mux(ssh);
1543 goto skip_connect;
1544 }
1545 }
1546
1547 /*
1548 * If hostname canonicalisation was not enabled, then we may not
1549 * have yet resolved the hostname. Do so now.
1550 */
1551 if (addrs == NULL && options.proxy_command == NULL) {
1552 debug2("resolving \"%s\" port %d", host, options.port);
1553 if ((addrs = resolve_host(host, options.port, 1,
1554 cname, sizeof(cname))) == NULL)
1555 cleanup_exit(255); /* resolve_host logs the error */
1556 }
1557
1558 if (options.connection_timeout >= INT_MAX/1000)
1559 timeout_ms = INT_MAX;
1560 else
1561 timeout_ms = options.connection_timeout * 1000;
1562
1563 /* Open a connection to the remote host. */
1564 if (ssh_connect(ssh, host, host_arg, addrs, &hostaddr, options.port,
1565 options.connection_attempts,
1566 &timeout_ms, options.tcp_keep_alive) != 0)
1567 exit(255);
1568
1569 if (addrs != NULL)
1570 freeaddrinfo(addrs);
1571
1572 ssh_packet_set_timeout(ssh, options.server_alive_interval,
1573 options.server_alive_count_max);
1574
1575 if (timeout_ms > 0)
1576 debug3("timeout: %d ms remain after connect", timeout_ms);
1577
1578 /*
1579 * If we successfully made the connection and we have hostbased auth
1580 * enabled, load the public keys so we can later use the ssh-keysign
1581 * helper to sign challenges.
1582 */
1583 sensitive_data.nkeys = 0;
1584 sensitive_data.keys = NULL;
1585 if (options.hostbased_authentication) {
1586 sensitive_data.nkeys = 10;
1587 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1588 sizeof(struct sshkey));
1589
1590 /* XXX check errors? */
1591 #define L_PUBKEY(p,o) do { \
1592 if ((o) >= sensitive_data.nkeys) \
1593 fatal_f("pubkey out of array bounds"); \
1594 check_load(sshkey_load_public(p, &(sensitive_data.keys[o]), NULL), \
1595 p, "pubkey"); \
1596 } while (0)
1597 #define L_CERT(p,o) do { \
1598 if ((o) >= sensitive_data.nkeys) \
1599 fatal_f("cert out of array bounds"); \
1600 check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert"); \
1601 } while (0)
1602
1603 if (options.hostbased_authentication == 1) {
1604 L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 0);
1605 L_CERT(_PATH_HOST_ED25519_KEY_FILE, 1);
1606 L_CERT(_PATH_HOST_RSA_KEY_FILE, 2);
1607 L_CERT(_PATH_HOST_DSA_KEY_FILE, 3);
1608 L_PUBKEY(_PATH_HOST_ECDSA_KEY_FILE, 4);
1609 L_PUBKEY(_PATH_HOST_ED25519_KEY_FILE, 5);
1610 L_PUBKEY(_PATH_HOST_RSA_KEY_FILE, 6);
1611 L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 7);
1612 L_CERT(_PATH_HOST_XMSS_KEY_FILE, 8);
1613 L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 9);
1614 }
1615 }
1616
1617 /* load options.identity_files */
1618 load_public_identity_files(cinfo);
1619
1620 /* optionally set the SSH_AUTHSOCKET_ENV_NAME variable */
1621 if (options.identity_agent &&
1622 strcmp(options.identity_agent, SSH_AUTHSOCKET_ENV_NAME) != 0) {
1623 if (strcmp(options.identity_agent, "none") == 0) {
1624 unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1625 } else {
1626 cp = options.identity_agent;
1627 /* legacy (limited) format */
1628 if (cp[0] == '$' && cp[1] != '{') {
1629 if (!valid_env_name(cp + 1)) {
1630 fatal("Invalid IdentityAgent "
1631 "environment variable name %s", cp);
1632 }
1633 if ((p = getenv(cp + 1)) == NULL)
1634 unsetenv(SSH_AUTHSOCKET_ENV_NAME);
1635 else
1636 setenv(SSH_AUTHSOCKET_ENV_NAME, p, 1);
1637 } else {
1638 /* identity_agent specifies a path directly */
1639 setenv(SSH_AUTHSOCKET_ENV_NAME, cp, 1);
1640 }
1641 }
1642 }
1643
1644 if (options.forward_agent && options.forward_agent_sock_path != NULL) {
1645 cp = options.forward_agent_sock_path;
1646 if (cp[0] == '$') {
1647 if (!valid_env_name(cp + 1)) {
1648 fatal("Invalid ForwardAgent environment variable name %s", cp);
1649 }
1650 if ((p = getenv(cp + 1)) != NULL)
1651 forward_agent_sock_path = xstrdup(p);
1652 else
1653 options.forward_agent = 0;
1654 free(cp);
1655 } else {
1656 forward_agent_sock_path = cp;
1657 }
1658 }
1659
1660 /* Expand ~ in known host file names. */
1661 tilde_expand_paths(options.system_hostfiles,
1662 options.num_system_hostfiles);
1663 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1664
1665 ssh_signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1666 ssh_signal(SIGCHLD, main_sigchld_handler);
1667
1668 /* Log into the remote system. Never returns if the login fails. */
1669 ssh_login(ssh, &sensitive_data, host, (struct sockaddr *)&hostaddr,
1670 options.port, pw, timeout_ms, cinfo);
1671
1672 /* We no longer need the private host keys. Clear them now. */
1673 if (sensitive_data.nkeys != 0) {
1674 for (i = 0; i < sensitive_data.nkeys; i++) {
1675 if (sensitive_data.keys[i] != NULL) {
1676 /* Destroys contents safely */
1677 debug3("clear hostkey %d", i);
1678 sshkey_free(sensitive_data.keys[i]);
1679 sensitive_data.keys[i] = NULL;
1680 }
1681 }
1682 free(sensitive_data.keys);
1683 }
1684 for (i = 0; i < options.num_identity_files; i++) {
1685 free(options.identity_files[i]);
1686 options.identity_files[i] = NULL;
1687 if (options.identity_keys[i]) {
1688 sshkey_free(options.identity_keys[i]);
1689 options.identity_keys[i] = NULL;
1690 }
1691 }
1692 for (i = 0; i < options.num_certificate_files; i++) {
1693 free(options.certificate_files[i]);
1694 options.certificate_files[i] = NULL;
1695 }
1696
1697 #ifdef ENABLE_PKCS11
1698 (void)pkcs11_del_provider(options.pkcs11_provider);
1699 #endif
1700
1701 skip_connect:
1702 exit_status = ssh_session2(ssh, cinfo);
1703 ssh_conn_info_free(cinfo);
1704 ssh_packet_close(ssh);
1705
1706 if (options.control_path != NULL && muxserver_sock != -1)
1707 unlink(options.control_path);
1708
1709 /* Kill ProxyCommand if it is running. */
1710 ssh_kill_proxy_command();
1711
1712 return exit_status;
1713 }
1714
1715 static void
control_persist_detach(void)1716 control_persist_detach(void)
1717 {
1718 pid_t pid;
1719
1720 debug_f("backgrounding master process");
1721
1722 /*
1723 * master (current process) into the background, and make the
1724 * foreground process a client of the backgrounded master.
1725 */
1726 switch ((pid = fork())) {
1727 case -1:
1728 fatal_f("fork: %s", strerror(errno));
1729 case 0:
1730 /* Child: master process continues mainloop */
1731 break;
1732 default:
1733 /* Parent: set up mux client to connect to backgrounded master */
1734 debug2_f("background process is %ld", (long)pid);
1735 options.stdin_null = ostdin_null_flag;
1736 options.request_tty = orequest_tty;
1737 tty_flag = otty_flag;
1738 options.session_type = osession_type;
1739 close(muxserver_sock);
1740 muxserver_sock = -1;
1741 options.control_master = SSHCTL_MASTER_NO;
1742 muxclient(options.control_path);
1743 /* muxclient() doesn't return on success. */
1744 fatal("Failed to connect to new control master");
1745 }
1746 if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1747 error_f("stdfd_devnull failed");
1748 daemon(1, 1);
1749 setproctitle("%s [mux]", options.control_path);
1750 }
1751
1752 /* Do fork() after authentication. Used by "ssh -f" */
1753 static void
fork_postauth(void)1754 fork_postauth(void)
1755 {
1756 if (need_controlpersist_detach)
1757 control_persist_detach();
1758 debug("forking to background");
1759 options.fork_after_authentication = 0;
1760 if (daemon(1, 1) == -1)
1761 fatal("daemon() failed: %.200s", strerror(errno));
1762 if (stdfd_devnull(1, 1, !(log_is_on_stderr() && debug_flag)) == -1)
1763 error_f("stdfd_devnull failed");
1764 }
1765
1766 static void
forwarding_success(void)1767 forwarding_success(void)
1768 {
1769 if (forward_confirms_pending == -1)
1770 return;
1771 if (--forward_confirms_pending == 0) {
1772 debug_f("all expected forwarding replies received");
1773 if (options.fork_after_authentication)
1774 fork_postauth();
1775 } else {
1776 debug2_f("%d expected forwarding replies remaining",
1777 forward_confirms_pending);
1778 }
1779 }
1780
1781 /* Callback for remote forward global requests */
1782 static void
ssh_confirm_remote_forward(struct ssh * ssh,int type,u_int32_t seq,void * ctxt)1783 ssh_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
1784 {
1785 struct Forward *rfwd = (struct Forward *)ctxt;
1786 u_int port;
1787 int r;
1788
1789 /* XXX verbose() on failure? */
1790 debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1791 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1792 rfwd->listen_path ? rfwd->listen_path :
1793 rfwd->listen_host ? rfwd->listen_host : "",
1794 (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1795 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1796 rfwd->connect_host, rfwd->connect_port);
1797 if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1798 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1799 if ((r = sshpkt_get_u32(ssh, &port)) != 0)
1800 fatal_fr(r, "parse packet");
1801 if (port > 65535) {
1802 error("Invalid allocated port %u for remote "
1803 "forward to %s:%d", port,
1804 rfwd->connect_host, rfwd->connect_port);
1805 /* Ensure failure processing runs below */
1806 type = SSH2_MSG_REQUEST_FAILURE;
1807 channel_update_permission(ssh,
1808 rfwd->handle, -1);
1809 } else {
1810 rfwd->allocated_port = (int)port;
1811 logit("Allocated port %u for remote "
1812 "forward to %s:%d",
1813 rfwd->allocated_port, rfwd->connect_path ?
1814 rfwd->connect_path : rfwd->connect_host,
1815 rfwd->connect_port);
1816 channel_update_permission(ssh,
1817 rfwd->handle, rfwd->allocated_port);
1818 }
1819 } else {
1820 channel_update_permission(ssh, rfwd->handle, -1);
1821 }
1822 }
1823
1824 if (type == SSH2_MSG_REQUEST_FAILURE) {
1825 if (options.exit_on_forward_failure) {
1826 if (rfwd->listen_path != NULL)
1827 fatal("Error: remote port forwarding failed "
1828 "for listen path %s", rfwd->listen_path);
1829 else
1830 fatal("Error: remote port forwarding failed "
1831 "for listen port %d", rfwd->listen_port);
1832 } else {
1833 if (rfwd->listen_path != NULL)
1834 logit("Warning: remote port forwarding failed "
1835 "for listen path %s", rfwd->listen_path);
1836 else
1837 logit("Warning: remote port forwarding failed "
1838 "for listen port %d", rfwd->listen_port);
1839 }
1840 }
1841 forwarding_success();
1842 }
1843
1844 static void
client_cleanup_stdio_fwd(struct ssh * ssh,int id,void * arg)1845 client_cleanup_stdio_fwd(struct ssh *ssh, int id, void *arg)
1846 {
1847 debug("stdio forwarding: done");
1848 cleanup_exit(0);
1849 }
1850
1851 static void
ssh_stdio_confirm(struct ssh * ssh,int id,int success,void * arg)1852 ssh_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1853 {
1854 if (!success)
1855 fatal("stdio forwarding failed");
1856 }
1857
1858 static void
ssh_tun_confirm(struct ssh * ssh,int id,int success,void * arg)1859 ssh_tun_confirm(struct ssh *ssh, int id, int success, void *arg)
1860 {
1861 if (!success) {
1862 error("Tunnel forwarding failed");
1863 if (options.exit_on_forward_failure)
1864 cleanup_exit(255);
1865 }
1866
1867 debug_f("tunnel forward established, id=%d", id);
1868 forwarding_success();
1869 }
1870
1871 static void
ssh_init_stdio_forwarding(struct ssh * ssh)1872 ssh_init_stdio_forwarding(struct ssh *ssh)
1873 {
1874 Channel *c;
1875 int in, out;
1876
1877 if (options.stdio_forward_host == NULL)
1878 return;
1879
1880 debug3_f("%s:%d", options.stdio_forward_host,
1881 options.stdio_forward_port);
1882
1883 if ((in = dup(STDIN_FILENO)) == -1 ||
1884 (out = dup(STDOUT_FILENO)) == -1)
1885 fatal_f("dup() in/out failed");
1886 if ((c = channel_connect_stdio_fwd(ssh, options.stdio_forward_host,
1887 options.stdio_forward_port, in, out,
1888 CHANNEL_NONBLOCK_STDIO)) == NULL)
1889 fatal_f("channel_connect_stdio_fwd failed");
1890 channel_register_cleanup(ssh, c->self, client_cleanup_stdio_fwd, 0);
1891 channel_register_open_confirm(ssh, c->self, ssh_stdio_confirm, NULL);
1892 }
1893
1894 static void
ssh_init_forward_permissions(struct ssh * ssh,const char * what,char ** opens,u_int num_opens)1895 ssh_init_forward_permissions(struct ssh *ssh, const char *what, char **opens,
1896 u_int num_opens)
1897 {
1898 u_int i;
1899 int port;
1900 char *addr, *arg, *oarg, ch;
1901 int where = FORWARD_LOCAL;
1902
1903 channel_clear_permission(ssh, FORWARD_ADM, where);
1904 if (num_opens == 0)
1905 return; /* permit any */
1906
1907 /* handle keywords: "any" / "none" */
1908 if (num_opens == 1 && strcmp(opens[0], "any") == 0)
1909 return;
1910 if (num_opens == 1 && strcmp(opens[0], "none") == 0) {
1911 channel_disable_admin(ssh, where);
1912 return;
1913 }
1914 /* Otherwise treat it as a list of permitted host:port */
1915 for (i = 0; i < num_opens; i++) {
1916 oarg = arg = xstrdup(opens[i]);
1917 ch = '\0';
1918 addr = hpdelim2(&arg, &ch);
1919 if (addr == NULL || ch == '/')
1920 fatal_f("missing host in %s", what);
1921 addr = cleanhostname(addr);
1922 if (arg == NULL || ((port = permitopen_port(arg)) < 0))
1923 fatal_f("bad port number in %s", what);
1924 /* Send it to channels layer */
1925 channel_add_permission(ssh, FORWARD_ADM,
1926 where, addr, port);
1927 free(oarg);
1928 }
1929 }
1930
1931 static void
ssh_init_forwarding(struct ssh * ssh,char ** ifname)1932 ssh_init_forwarding(struct ssh *ssh, char **ifname)
1933 {
1934 int success = 0;
1935 int i;
1936
1937 ssh_init_forward_permissions(ssh, "permitremoteopen",
1938 options.permitted_remote_opens,
1939 options.num_permitted_remote_opens);
1940
1941 if (options.exit_on_forward_failure)
1942 forward_confirms_pending = 0; /* track pending requests */
1943 /* Initiate local TCP/IP port forwardings. */
1944 for (i = 0; i < options.num_local_forwards; i++) {
1945 debug("Local connections to %.200s:%d forwarded to remote "
1946 "address %.200s:%d",
1947 (options.local_forwards[i].listen_path != NULL) ?
1948 options.local_forwards[i].listen_path :
1949 (options.local_forwards[i].listen_host == NULL) ?
1950 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1951 options.local_forwards[i].listen_host,
1952 options.local_forwards[i].listen_port,
1953 (options.local_forwards[i].connect_path != NULL) ?
1954 options.local_forwards[i].connect_path :
1955 options.local_forwards[i].connect_host,
1956 options.local_forwards[i].connect_port);
1957 success += channel_setup_local_fwd_listener(ssh,
1958 &options.local_forwards[i], &options.fwd_opts);
1959 }
1960 if (i > 0 && success != i && options.exit_on_forward_failure)
1961 fatal("Could not request local forwarding.");
1962 if (i > 0 && success == 0)
1963 error("Could not request local forwarding.");
1964
1965 /* Initiate remote TCP/IP port forwardings. */
1966 for (i = 0; i < options.num_remote_forwards; i++) {
1967 debug("Remote connections from %.200s:%d forwarded to "
1968 "local address %.200s:%d",
1969 (options.remote_forwards[i].listen_path != NULL) ?
1970 options.remote_forwards[i].listen_path :
1971 (options.remote_forwards[i].listen_host == NULL) ?
1972 "LOCALHOST" : options.remote_forwards[i].listen_host,
1973 options.remote_forwards[i].listen_port,
1974 (options.remote_forwards[i].connect_path != NULL) ?
1975 options.remote_forwards[i].connect_path :
1976 options.remote_forwards[i].connect_host,
1977 options.remote_forwards[i].connect_port);
1978 if ((options.remote_forwards[i].handle =
1979 channel_request_remote_forwarding(ssh,
1980 &options.remote_forwards[i])) >= 0) {
1981 client_register_global_confirm(
1982 ssh_confirm_remote_forward,
1983 &options.remote_forwards[i]);
1984 forward_confirms_pending++;
1985 } else if (options.exit_on_forward_failure)
1986 fatal("Could not request remote forwarding.");
1987 else
1988 logit("Warning: Could not request remote forwarding.");
1989 }
1990
1991 /* Initiate tunnel forwarding. */
1992 if (options.tun_open != SSH_TUNMODE_NO) {
1993 if ((*ifname = client_request_tun_fwd(ssh,
1994 options.tun_open, options.tun_local,
1995 options.tun_remote, ssh_tun_confirm, NULL)) != NULL)
1996 forward_confirms_pending++;
1997 else if (options.exit_on_forward_failure)
1998 fatal("Could not request tunnel forwarding.");
1999 else
2000 error("Could not request tunnel forwarding.");
2001 }
2002 if (forward_confirms_pending > 0) {
2003 debug_f("expecting replies for %d forwards",
2004 forward_confirms_pending);
2005 }
2006 }
2007
2008 static void
check_agent_present(void)2009 check_agent_present(void)
2010 {
2011 int r;
2012
2013 if (options.forward_agent) {
2014 /* Clear agent forwarding if we don't have an agent. */
2015 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
2016 options.forward_agent = 0;
2017 if (r != SSH_ERR_AGENT_NOT_PRESENT)
2018 debug_r(r, "ssh_get_authentication_socket");
2019 }
2020 }
2021 }
2022
2023 static void
ssh_session2_setup(struct ssh * ssh,int id,int success,void * arg)2024 ssh_session2_setup(struct ssh *ssh, int id, int success, void *arg)
2025 {
2026 extern char **environ;
2027 const char *display, *term;
2028 int r, interactive = tty_flag;
2029 char *proto = NULL, *data = NULL;
2030
2031 if (!success)
2032 return; /* No need for error message, channels code sens one */
2033
2034 display = getenv("DISPLAY");
2035 if (display == NULL && options.forward_x11)
2036 debug("X11 forwarding requested but DISPLAY not set");
2037 if (options.forward_x11 && client_x11_get_proto(ssh, display,
2038 options.xauth_location, options.forward_x11_trusted,
2039 options.forward_x11_timeout, &proto, &data) == 0) {
2040 /* Request forwarding with authentication spoofing. */
2041 debug("Requesting X11 forwarding with authentication "
2042 "spoofing.");
2043 x11_request_forwarding_with_spoofing(ssh, id, display, proto,
2044 data, 1);
2045 client_expect_confirm(ssh, id, "X11 forwarding", CONFIRM_WARN);
2046 /* XXX exit_on_forward_failure */
2047 interactive = 1;
2048 }
2049
2050 check_agent_present();
2051 if (options.forward_agent) {
2052 debug("Requesting authentication agent forwarding.");
2053 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
2054 if ((r = sshpkt_send(ssh)) != 0)
2055 fatal_fr(r, "send packet");
2056 }
2057
2058 /* Tell the packet module whether this is an interactive session. */
2059 ssh_packet_set_interactive(ssh, interactive,
2060 options.ip_qos_interactive, options.ip_qos_bulk);
2061
2062 if ((term = lookup_env_in_list("TERM", options.setenv,
2063 options.num_setenv)) == NULL || *term == '\0')
2064 term = getenv("TERM");
2065 client_session2_setup(ssh, id, tty_flag,
2066 options.session_type == SESSION_TYPE_SUBSYSTEM, term,
2067 NULL, fileno(stdin), command, environ);
2068 }
2069
2070 /* open new channel for a session */
2071 static int
ssh_session2_open(struct ssh * ssh)2072 ssh_session2_open(struct ssh *ssh)
2073 {
2074 Channel *c;
2075 int window, packetmax, in, out, err;
2076
2077 if (options.stdin_null) {
2078 in = open(_PATH_DEVNULL, O_RDONLY);
2079 } else {
2080 in = dup(STDIN_FILENO);
2081 }
2082 out = dup(STDOUT_FILENO);
2083 err = dup(STDERR_FILENO);
2084
2085 if (in == -1 || out == -1 || err == -1)
2086 fatal("dup() in/out/err failed");
2087
2088 window = CHAN_SES_WINDOW_DEFAULT;
2089 packetmax = CHAN_SES_PACKET_DEFAULT;
2090 if (tty_flag) {
2091 window >>= 1;
2092 packetmax >>= 1;
2093 }
2094 c = channel_new(ssh,
2095 "session", SSH_CHANNEL_OPENING, in, out, err,
2096 window, packetmax, CHAN_EXTENDED_WRITE,
2097 "client-session", CHANNEL_NONBLOCK_STDIO);
2098
2099 debug3_f("channel_new: %d", c->self);
2100
2101 channel_send_open(ssh, c->self);
2102 if (options.session_type != SESSION_TYPE_NONE)
2103 channel_register_open_confirm(ssh, c->self,
2104 ssh_session2_setup, NULL);
2105
2106 return c->self;
2107 }
2108
2109 static int
ssh_session2(struct ssh * ssh,const struct ssh_conn_info * cinfo)2110 ssh_session2(struct ssh *ssh, const struct ssh_conn_info *cinfo)
2111 {
2112 int r, id = -1;
2113 char *cp, *tun_fwd_ifname = NULL;
2114
2115 /* XXX should be pre-session */
2116 if (!options.control_persist)
2117 ssh_init_stdio_forwarding(ssh);
2118
2119 ssh_init_forwarding(ssh, &tun_fwd_ifname);
2120
2121 if (options.local_command != NULL) {
2122 debug3("expanding LocalCommand: %s", options.local_command);
2123 cp = options.local_command;
2124 options.local_command = percent_expand(cp,
2125 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
2126 "T", tun_fwd_ifname == NULL ? "NONE" : tun_fwd_ifname,
2127 (char *)NULL);
2128 debug3("expanded LocalCommand: %s", options.local_command);
2129 free(cp);
2130 }
2131
2132 /* Start listening for multiplex clients */
2133 if (!ssh_packet_get_mux(ssh))
2134 muxserver_listen(ssh);
2135
2136 /*
2137 * If we are in control persist mode and have a working mux listen
2138 * socket, then prepare to background ourselves and have a foreground
2139 * client attach as a control client.
2140 * NB. we must save copies of the flags that we override for
2141 * the backgrounding, since we defer attachment of the client until
2142 * after the connection is fully established (in particular,
2143 * async rfwd replies have been received for ExitOnForwardFailure).
2144 */
2145 if (options.control_persist && muxserver_sock != -1) {
2146 ostdin_null_flag = options.stdin_null;
2147 osession_type = options.session_type;
2148 orequest_tty = options.request_tty;
2149 otty_flag = tty_flag;
2150 options.stdin_null = 1;
2151 options.session_type = SESSION_TYPE_NONE;
2152 tty_flag = 0;
2153 if (!options.fork_after_authentication &&
2154 (osession_type != SESSION_TYPE_NONE ||
2155 options.stdio_forward_host != NULL))
2156 need_controlpersist_detach = 1;
2157 options.fork_after_authentication = 1;
2158 }
2159 /*
2160 * ControlPersist mux listen socket setup failed, attempt the
2161 * stdio forward setup that we skipped earlier.
2162 */
2163 if (options.control_persist && muxserver_sock == -1)
2164 ssh_init_stdio_forwarding(ssh);
2165
2166 if (options.session_type != SESSION_TYPE_NONE)
2167 id = ssh_session2_open(ssh);
2168 else {
2169 ssh_packet_set_interactive(ssh,
2170 options.control_master == SSHCTL_MASTER_NO,
2171 options.ip_qos_interactive, options.ip_qos_bulk);
2172 }
2173
2174 /* If we don't expect to open a new session, then disallow it */
2175 if (options.control_master == SSHCTL_MASTER_NO &&
2176 (ssh->compat & SSH_NEW_OPENSSH)) {
2177 debug("Requesting no-more-sessions@openssh.com");
2178 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2179 (r = sshpkt_put_cstring(ssh,
2180 "no-more-sessions@openssh.com")) != 0 ||
2181 (r = sshpkt_put_u8(ssh, 0)) != 0 ||
2182 (r = sshpkt_send(ssh)) != 0)
2183 fatal_fr(r, "send packet");
2184 }
2185
2186 /* Execute a local command */
2187 if (options.local_command != NULL &&
2188 options.permit_local_command)
2189 ssh_local_cmd(options.local_command);
2190
2191 /*
2192 * stdout is now owned by the session channel; clobber it here
2193 * so future channel closes are propagated to the local fd.
2194 * NB. this can only happen after LocalCommand has completed,
2195 * as it may want to write to stdout.
2196 */
2197 if (!need_controlpersist_detach && stdfd_devnull(0, 1, 0) == -1)
2198 error_f("stdfd_devnull failed");
2199
2200 /*
2201 * If requested and we are not interested in replies to remote
2202 * forwarding requests, then let ssh continue in the background.
2203 */
2204 if (options.fork_after_authentication) {
2205 if (options.exit_on_forward_failure &&
2206 options.num_remote_forwards > 0) {
2207 debug("deferring postauth fork until remote forward "
2208 "confirmation received");
2209 } else
2210 fork_postauth();
2211 }
2212
2213 return client_loop(ssh, tty_flag, tty_flag ?
2214 options.escape_char : SSH_ESCAPECHAR_NONE, id);
2215 }
2216
2217 /* Loads all IdentityFile and CertificateFile keys */
2218 static void
load_public_identity_files(const struct ssh_conn_info * cinfo)2219 load_public_identity_files(const struct ssh_conn_info *cinfo)
2220 {
2221 char *filename, *cp;
2222 struct sshkey *public;
2223 int i;
2224 u_int n_ids, n_certs;
2225 char *identity_files[SSH_MAX_IDENTITY_FILES];
2226 struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
2227 int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
2228 char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
2229 struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
2230 int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
2231 #ifdef ENABLE_PKCS11
2232 struct sshkey **keys = NULL;
2233 char **comments = NULL;
2234 int nkeys;
2235 #endif /* PKCS11 */
2236
2237 n_ids = n_certs = 0;
2238 memset(identity_files, 0, sizeof(identity_files));
2239 memset(identity_keys, 0, sizeof(identity_keys));
2240 memset(identity_file_userprovided, 0,
2241 sizeof(identity_file_userprovided));
2242 memset(certificate_files, 0, sizeof(certificate_files));
2243 memset(certificates, 0, sizeof(certificates));
2244 memset(certificate_file_userprovided, 0,
2245 sizeof(certificate_file_userprovided));
2246
2247 #ifdef ENABLE_PKCS11
2248 if (options.pkcs11_provider != NULL &&
2249 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
2250 (pkcs11_init(!options.batch_mode) == 0) &&
2251 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
2252 &keys, &comments)) > 0) {
2253 for (i = 0; i < nkeys; i++) {
2254 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2255 sshkey_free(keys[i]);
2256 free(comments[i]);
2257 continue;
2258 }
2259 identity_keys[n_ids] = keys[i];
2260 identity_files[n_ids] = comments[i]; /* transferred */
2261 n_ids++;
2262 }
2263 free(keys);
2264 free(comments);
2265 }
2266 #endif /* ENABLE_PKCS11 */
2267 for (i = 0; i < options.num_identity_files; i++) {
2268 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2269 strcasecmp(options.identity_files[i], "none") == 0) {
2270 free(options.identity_files[i]);
2271 options.identity_files[i] = NULL;
2272 continue;
2273 }
2274 cp = tilde_expand_filename(options.identity_files[i], getuid());
2275 filename = default_client_percent_dollar_expand(cp, cinfo);
2276 free(cp);
2277 check_load(sshkey_load_public(filename, &public, NULL),
2278 filename, "pubkey");
2279 debug("identity file %s type %d", filename,
2280 public ? public->type : -1);
2281 free(options.identity_files[i]);
2282 identity_files[n_ids] = filename;
2283 identity_keys[n_ids] = public;
2284 identity_file_userprovided[n_ids] =
2285 options.identity_file_userprovided[i];
2286 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2287 continue;
2288
2289 /*
2290 * If no certificates have been explicitly listed then try
2291 * to add the default certificate variant too.
2292 */
2293 if (options.num_certificate_files != 0)
2294 continue;
2295 xasprintf(&cp, "%s-cert", filename);
2296 check_load(sshkey_load_public(cp, &public, NULL),
2297 filename, "pubkey");
2298 debug("identity file %s type %d", cp,
2299 public ? public->type : -1);
2300 if (public == NULL) {
2301 free(cp);
2302 continue;
2303 }
2304 if (!sshkey_is_cert(public)) {
2305 debug_f("key %s type %s is not a certificate",
2306 cp, sshkey_type(public));
2307 sshkey_free(public);
2308 free(cp);
2309 continue;
2310 }
2311 /* NB. leave filename pointing to private key */
2312 identity_files[n_ids] = xstrdup(filename);
2313 identity_keys[n_ids] = public;
2314 identity_file_userprovided[n_ids] =
2315 options.identity_file_userprovided[i];
2316 n_ids++;
2317 }
2318
2319 if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2320 fatal_f("too many certificates");
2321 for (i = 0; i < options.num_certificate_files; i++) {
2322 cp = tilde_expand_filename(options.certificate_files[i],
2323 getuid());
2324 filename = default_client_percent_dollar_expand(cp, cinfo);
2325 free(cp);
2326
2327 check_load(sshkey_load_public(filename, &public, NULL),
2328 filename, "certificate");
2329 debug("certificate file %s type %d", filename,
2330 public ? public->type : -1);
2331 free(options.certificate_files[i]);
2332 options.certificate_files[i] = NULL;
2333 if (public == NULL) {
2334 free(filename);
2335 continue;
2336 }
2337 if (!sshkey_is_cert(public)) {
2338 debug_f("key %s type %s is not a certificate",
2339 filename, sshkey_type(public));
2340 sshkey_free(public);
2341 free(filename);
2342 continue;
2343 }
2344 certificate_files[n_certs] = filename;
2345 certificates[n_certs] = public;
2346 certificate_file_userprovided[n_certs] =
2347 options.certificate_file_userprovided[i];
2348 ++n_certs;
2349 }
2350
2351 options.num_identity_files = n_ids;
2352 memcpy(options.identity_files, identity_files, sizeof(identity_files));
2353 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2354 memcpy(options.identity_file_userprovided,
2355 identity_file_userprovided, sizeof(identity_file_userprovided));
2356
2357 options.num_certificate_files = n_certs;
2358 memcpy(options.certificate_files,
2359 certificate_files, sizeof(certificate_files));
2360 memcpy(options.certificates, certificates, sizeof(certificates));
2361 memcpy(options.certificate_file_userprovided,
2362 certificate_file_userprovided,
2363 sizeof(certificate_file_userprovided));
2364 }
2365
2366 static void
main_sigchld_handler(int sig)2367 main_sigchld_handler(int sig)
2368 {
2369 int save_errno = errno;
2370 pid_t pid;
2371 int status;
2372
2373 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2374 (pid == -1 && errno == EINTR))
2375 ;
2376 errno = save_errno;
2377 }
2378