1 /* $OpenBSD: ssh.c,v 1.401 2014/02/26 20:18:37 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 SSL by Niels Provos <provos@citi.umich.edu>
20 * in Canada (German citizen).
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the above copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 */
42
43 #include "includes.h"
44 __RCSID("$FreeBSD$");
45
46 #include <sys/types.h>
47 #ifdef HAVE_SYS_STAT_H
48 # include <sys/stat.h>
49 #endif
50 #include <sys/resource.h>
51 #include <sys/ioctl.h>
52 #include <sys/param.h>
53 #include <sys/socket.h>
54 #include <sys/wait.h>
55
56 #include <ctype.h>
57 #include <errno.h>
58 #include <fcntl.h>
59 #include <netdb.h>
60 #ifdef HAVE_PATHS_H
61 #include <paths.h>
62 #endif
63 #include <pwd.h>
64 #include <signal.h>
65 #include <stdarg.h>
66 #include <stddef.h>
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #include <unistd.h>
71
72 #include <netinet/in.h>
73 #include <arpa/inet.h>
74
75 #include <openssl/evp.h>
76 #include <openssl/err.h>
77 #include "openbsd-compat/openssl-compat.h"
78 #include "openbsd-compat/sys-queue.h"
79
80 #include "xmalloc.h"
81 #include "ssh.h"
82 #include "ssh1.h"
83 #include "ssh2.h"
84 #include "canohost.h"
85 #include "compat.h"
86 #include "cipher.h"
87 #include "packet.h"
88 #include "buffer.h"
89 #include "channels.h"
90 #include "key.h"
91 #include "authfd.h"
92 #include "authfile.h"
93 #include "pathnames.h"
94 #include "dispatch.h"
95 #include "clientloop.h"
96 #include "log.h"
97 #include "readconf.h"
98 #include "sshconnect.h"
99 #include "misc.h"
100 #include "kex.h"
101 #include "mac.h"
102 #include "sshpty.h"
103 #include "match.h"
104 #include "msg.h"
105 #include "uidswap.h"
106 #include "roaming.h"
107 #include "version.h"
108
109 #ifdef ENABLE_PKCS11
110 #include "ssh-pkcs11.h"
111 #endif
112
113 extern char *__progname;
114
115 /* Saves a copy of argv for setproctitle emulation */
116 #ifndef HAVE_SETPROCTITLE
117 static char **saved_av;
118 #endif
119
120 /* Flag indicating whether debug mode is on. May be set on the command line. */
121 int debug_flag = 0;
122
123 /* Flag indicating whether a tty should be requested */
124 int tty_flag = 0;
125
126 /* don't exec a shell */
127 int no_shell_flag = 0;
128
129 /*
130 * Flag indicating that nothing should be read from stdin. This can be set
131 * on the command line.
132 */
133 int stdin_null_flag = 0;
134
135 /*
136 * Flag indicating that the current process should be backgrounded and
137 * a new slave launched in the foreground for ControlPersist.
138 */
139 int need_controlpersist_detach = 0;
140
141 /* Copies of flags for ControlPersist foreground slave */
142 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
143
144 /*
145 * Flag indicating that ssh should fork after authentication. This is useful
146 * so that the passphrase can be entered manually, and then ssh goes to the
147 * background.
148 */
149 int fork_after_authentication_flag = 0;
150
151 /* forward stdio to remote host and port */
152 char *stdio_forward_host = NULL;
153 int stdio_forward_port = 0;
154
155 /*
156 * General data structure for command line options and options configurable
157 * in configuration files. See readconf.h.
158 */
159 Options options;
160
161 /* optional user configfile */
162 char *config = NULL;
163
164 /*
165 * Name of the host we are connecting to. This is the name given on the
166 * command line, or the HostName specified for the user-supplied name in a
167 * configuration file.
168 */
169 char *host;
170
171 /* socket address the host resolves to */
172 struct sockaddr_storage hostaddr;
173
174 /* Private host keys. */
175 Sensitive sensitive_data;
176
177 /* Original real UID. */
178 uid_t original_real_uid;
179 uid_t original_effective_uid;
180
181 /* command to be executed */
182 Buffer command;
183
184 /* Should we execute a command or invoke a subsystem? */
185 int subsystem_flag = 0;
186
187 /* # of replies received for global requests */
188 static int remote_forward_confirms_received = 0;
189
190 /* mux.c */
191 extern int muxserver_sock;
192 extern u_int muxclient_command;
193
194 /* Prints a help message to the user. This function never returns. */
195
196 static void
usage(void)197 usage(void)
198 {
199 fprintf(stderr,
200 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
201 " [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
202 " [-F configfile] [-I pkcs11] [-i identity_file]\n"
203 " [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n"
204 " [-O ctl_cmd] [-o option] [-p port]\n"
205 " [-Q cipher | cipher-auth | mac | kex | key]\n"
206 " [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n"
207 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
208 );
209 exit(255);
210 }
211
212 static int ssh_session(void);
213 static int ssh_session2(void);
214 static void load_public_identity_files(void);
215 static void main_sigchld_handler(int);
216
217 /* from muxclient.c */
218 void muxclient(const char *);
219 void muxserver_listen(void);
220
221 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
222 static void
tilde_expand_paths(char ** paths,u_int num_paths)223 tilde_expand_paths(char **paths, u_int num_paths)
224 {
225 u_int i;
226 char *cp;
227
228 for (i = 0; i < num_paths; i++) {
229 cp = tilde_expand_filename(paths[i], original_real_uid);
230 free(paths[i]);
231 paths[i] = cp;
232 }
233 }
234
235 /*
236 * Attempt to resolve a host name / port to a set of addresses and
237 * optionally return any CNAMEs encountered along the way.
238 * Returns NULL on failure.
239 * NB. this function must operate with a options having undefined members.
240 */
241 static struct addrinfo *
resolve_host(const char * name,int port,int logerr,char * cname,size_t clen)242 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
243 {
244 char strport[NI_MAXSERV];
245 struct addrinfo hints, *res;
246 int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
247
248 if (port <= 0)
249 port = default_ssh_port();
250
251 snprintf(strport, sizeof strport, "%u", port);
252 memset(&hints, 0, sizeof(hints));
253 hints.ai_family = options.address_family == -1 ?
254 AF_UNSPEC : options.address_family;
255 hints.ai_socktype = SOCK_STREAM;
256 if (cname != NULL)
257 hints.ai_flags = AI_CANONNAME;
258 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
259 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
260 loglevel = SYSLOG_LEVEL_ERROR;
261 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
262 __progname, name, ssh_gai_strerror(gaierr));
263 return NULL;
264 }
265 if (cname != NULL && res->ai_canonname != NULL) {
266 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
267 error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
268 __func__, name, res->ai_canonname, (u_long)clen);
269 if (clen > 0)
270 *cname = '\0';
271 }
272 }
273 return res;
274 }
275
276 /*
277 * Check whether the cname is a permitted replacement for the hostname
278 * and perform the replacement if it is.
279 * NB. this function must operate with a options having undefined members.
280 */
281 static int
check_follow_cname(char ** namep,const char * cname)282 check_follow_cname(char **namep, const char *cname)
283 {
284 int i;
285 struct allowed_cname *rule;
286
287 if (*cname == '\0' || options.num_permitted_cnames == 0 ||
288 strcmp(*namep, cname) == 0)
289 return 0;
290 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
291 return 0;
292 /*
293 * Don't attempt to canonicalize names that will be interpreted by
294 * a proxy unless the user specifically requests so.
295 */
296 if (!option_clear_or_none(options.proxy_command) &&
297 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
298 return 0;
299 debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
300 for (i = 0; i < options.num_permitted_cnames; i++) {
301 rule = options.permitted_cnames + i;
302 if (match_pattern_list(*namep, rule->source_list,
303 strlen(rule->source_list), 1) != 1 ||
304 match_pattern_list(cname, rule->target_list,
305 strlen(rule->target_list), 1) != 1)
306 continue;
307 verbose("Canonicalized DNS aliased hostname "
308 "\"%s\" => \"%s\"", *namep, cname);
309 free(*namep);
310 *namep = xstrdup(cname);
311 return 1;
312 }
313 return 0;
314 }
315
316 /*
317 * Attempt to resolve the supplied hostname after applying the user's
318 * canonicalization rules. Returns the address list for the host or NULL
319 * if no name was found after canonicalization.
320 * NB. this function must operate with a options having undefined members.
321 */
322 static struct addrinfo *
resolve_canonicalize(char ** hostp,int port)323 resolve_canonicalize(char **hostp, int port)
324 {
325 int i, ndots;
326 char *cp, *fullhost, cname_target[NI_MAXHOST];
327 struct addrinfo *addrs;
328
329 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
330 return NULL;
331
332 /*
333 * Don't attempt to canonicalize names that will be interpreted by
334 * a proxy unless the user specifically requests so.
335 */
336 if (!option_clear_or_none(options.proxy_command) &&
337 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
338 return NULL;
339
340 /* Don't apply canonicalization to sufficiently-qualified hostnames */
341 ndots = 0;
342 for (cp = *hostp; *cp != '\0'; cp++) {
343 if (*cp == '.')
344 ndots++;
345 }
346 if (ndots > options.canonicalize_max_dots) {
347 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
348 __func__, *hostp, options.canonicalize_max_dots);
349 return NULL;
350 }
351 /* Attempt each supplied suffix */
352 for (i = 0; i < options.num_canonical_domains; i++) {
353 *cname_target = '\0';
354 xasprintf(&fullhost, "%s.%s.", *hostp,
355 options.canonical_domains[i]);
356 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
357 *hostp, fullhost);
358 if ((addrs = resolve_host(fullhost, port, 0,
359 cname_target, sizeof(cname_target))) == NULL) {
360 free(fullhost);
361 continue;
362 }
363 /* Remove trailing '.' */
364 fullhost[strlen(fullhost) - 1] = '\0';
365 /* Follow CNAME if requested */
366 if (!check_follow_cname(&fullhost, cname_target)) {
367 debug("Canonicalized hostname \"%s\" => \"%s\"",
368 *hostp, fullhost);
369 }
370 free(*hostp);
371 *hostp = fullhost;
372 return addrs;
373 }
374 if (!options.canonicalize_fallback_local)
375 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
376 debug2("%s: host %s not found in any suffix", __func__, *hostp);
377 return NULL;
378 }
379
380 /*
381 * Read per-user configuration file. Ignore the system wide config
382 * file if the user specifies a config file on the command line.
383 */
384 static void
process_config_files(struct passwd * pw)385 process_config_files(struct passwd *pw)
386 {
387 char buf[MAXPATHLEN];
388 int r;
389
390 if (config != NULL) {
391 if (strcasecmp(config, "none") != 0 &&
392 !read_config_file(config, pw, host, &options,
393 SSHCONF_USERCONF))
394 fatal("Can't open user config file %.100s: "
395 "%.100s", config, strerror(errno));
396 } else {
397 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
398 _PATH_SSH_USER_CONFFILE);
399 if (r > 0 && (size_t)r < sizeof(buf))
400 (void)read_config_file(buf, pw, host, &options,
401 SSHCONF_CHECKPERM|SSHCONF_USERCONF);
402
403 /* Read systemwide configuration file after user config. */
404 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host,
405 &options, 0);
406 }
407 }
408
409 /*
410 * Main program for the ssh client.
411 */
412 int
main(int ac,char ** av)413 main(int ac, char **av)
414 {
415 int i, r, opt, exit_status, use_syslog;
416 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile;
417 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
418 char cname[NI_MAXHOST];
419 struct stat st;
420 struct passwd *pw;
421 int timeout_ms;
422 extern int optind, optreset;
423 extern char *optarg;
424 Forward fwd;
425 struct addrinfo *addrs = NULL;
426
427 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
428 sanitise_stdfd();
429
430 __progname = ssh_get_progname(av[0]);
431
432 #ifndef HAVE_SETPROCTITLE
433 /* Prepare for later setproctitle emulation */
434 /* Save argv so it isn't clobbered by setproctitle() emulation */
435 saved_av = xcalloc(ac + 1, sizeof(*saved_av));
436 for (i = 0; i < ac; i++)
437 saved_av[i] = xstrdup(av[i]);
438 saved_av[i] = NULL;
439 compat_init_setproctitle(ac, av);
440 av = saved_av;
441 #endif
442
443 /*
444 * Discard other fds that are hanging around. These can cause problem
445 * with backgrounded ssh processes started by ControlPersist.
446 */
447 closefrom(STDERR_FILENO + 1);
448
449 /*
450 * Save the original real uid. It will be needed later (uid-swapping
451 * may clobber the real uid).
452 */
453 original_real_uid = getuid();
454 original_effective_uid = geteuid();
455
456 /*
457 * Use uid-swapping to give up root privileges for the duration of
458 * option processing. We will re-instantiate the rights when we are
459 * ready to create the privileged port, and will permanently drop
460 * them when the port has been created (actually, when the connection
461 * has been made, as we may need to create the port several times).
462 */
463 PRIV_END;
464
465 #ifdef HAVE_SETRLIMIT
466 /* If we are installed setuid root be careful to not drop core. */
467 if (original_real_uid != original_effective_uid) {
468 struct rlimit rlim;
469 rlim.rlim_cur = rlim.rlim_max = 0;
470 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
471 fatal("setrlimit failed: %.100s", strerror(errno));
472 }
473 #endif
474 /* Get user data. */
475 pw = getpwuid(original_real_uid);
476 if (!pw) {
477 logit("No user exists for uid %lu", (u_long)original_real_uid);
478 exit(255);
479 }
480 /* Take a copy of the returned structure. */
481 pw = pwcopy(pw);
482
483 /*
484 * Set our umask to something reasonable, as some files are created
485 * with the default umask. This will make them world-readable but
486 * writable only by the owner, which is ok for all files for which we
487 * don't set the modes explicitly.
488 */
489 umask(022);
490
491 /*
492 * Initialize option structure to indicate that no values have been
493 * set.
494 */
495 initialize_options(&options);
496
497 /* Parse command-line arguments. */
498 host = NULL;
499 use_syslog = 0;
500 logfile = NULL;
501 argv0 = av[0];
502
503 again:
504 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
505 "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
506 switch (opt) {
507 case '1':
508 options.protocol = SSH_PROTO_1;
509 break;
510 case '2':
511 options.protocol = SSH_PROTO_2;
512 break;
513 case '4':
514 options.address_family = AF_INET;
515 break;
516 case '6':
517 options.address_family = AF_INET6;
518 break;
519 case 'n':
520 stdin_null_flag = 1;
521 break;
522 case 'f':
523 fork_after_authentication_flag = 1;
524 stdin_null_flag = 1;
525 break;
526 case 'x':
527 options.forward_x11 = 0;
528 break;
529 case 'X':
530 options.forward_x11 = 1;
531 break;
532 case 'y':
533 use_syslog = 1;
534 break;
535 case 'E':
536 logfile = xstrdup(optarg);
537 break;
538 case 'Y':
539 options.forward_x11 = 1;
540 options.forward_x11_trusted = 1;
541 break;
542 case 'g':
543 options.gateway_ports = 1;
544 break;
545 case 'O':
546 if (stdio_forward_host != NULL)
547 fatal("Cannot specify multiplexing "
548 "command with -W");
549 else if (muxclient_command != 0)
550 fatal("Multiplexing command already specified");
551 if (strcmp(optarg, "check") == 0)
552 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
553 else if (strcmp(optarg, "forward") == 0)
554 muxclient_command = SSHMUX_COMMAND_FORWARD;
555 else if (strcmp(optarg, "exit") == 0)
556 muxclient_command = SSHMUX_COMMAND_TERMINATE;
557 else if (strcmp(optarg, "stop") == 0)
558 muxclient_command = SSHMUX_COMMAND_STOP;
559 else if (strcmp(optarg, "cancel") == 0)
560 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
561 else
562 fatal("Invalid multiplex command.");
563 break;
564 case 'P': /* deprecated */
565 options.use_privileged_port = 0;
566 break;
567 case 'Q':
568 cp = NULL;
569 if (strcmp(optarg, "cipher") == 0)
570 cp = cipher_alg_list('\n', 0);
571 else if (strcmp(optarg, "cipher-auth") == 0)
572 cp = cipher_alg_list('\n', 1);
573 else if (strcmp(optarg, "mac") == 0)
574 cp = mac_alg_list('\n');
575 else if (strcmp(optarg, "kex") == 0)
576 cp = kex_alg_list('\n');
577 else if (strcmp(optarg, "key") == 0)
578 cp = key_alg_list(0, 0);
579 else if (strcmp(optarg, "key-cert") == 0)
580 cp = key_alg_list(1, 0);
581 else if (strcmp(optarg, "key-plain") == 0)
582 cp = key_alg_list(0, 1);
583 if (cp == NULL)
584 fatal("Unsupported query \"%s\"", optarg);
585 printf("%s\n", cp);
586 free(cp);
587 exit(0);
588 break;
589 case 'a':
590 options.forward_agent = 0;
591 break;
592 case 'A':
593 options.forward_agent = 1;
594 break;
595 case 'k':
596 options.gss_deleg_creds = 0;
597 break;
598 case 'K':
599 options.gss_authentication = 1;
600 options.gss_deleg_creds = 1;
601 break;
602 case 'i':
603 if (stat(optarg, &st) < 0) {
604 fprintf(stderr, "Warning: Identity file %s "
605 "not accessible: %s.\n", optarg,
606 strerror(errno));
607 break;
608 }
609 add_identity_file(&options, NULL, optarg, 1);
610 break;
611 case 'I':
612 #ifdef ENABLE_PKCS11
613 options.pkcs11_provider = xstrdup(optarg);
614 #else
615 fprintf(stderr, "no support for PKCS#11.\n");
616 #endif
617 break;
618 case 't':
619 if (options.request_tty == REQUEST_TTY_YES)
620 options.request_tty = REQUEST_TTY_FORCE;
621 else
622 options.request_tty = REQUEST_TTY_YES;
623 break;
624 case 'v':
625 if (debug_flag == 0) {
626 debug_flag = 1;
627 options.log_level = SYSLOG_LEVEL_DEBUG1;
628 } else {
629 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
630 options.log_level++;
631 }
632 break;
633 case 'V':
634 if (options.version_addendum &&
635 *options.version_addendum != '\0')
636 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
637 options.hpn_disabled ? "" : SSH_VERSION_HPN,
638 options.version_addendum,
639 SSLeay_version(SSLEAY_VERSION));
640 else
641 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE,
642 options.hpn_disabled ? "" : SSH_VERSION_HPN,
643 SSLeay_version(SSLEAY_VERSION));
644 if (opt == 'V')
645 exit(0);
646 break;
647 case 'w':
648 if (options.tun_open == -1)
649 options.tun_open = SSH_TUNMODE_DEFAULT;
650 options.tun_local = a2tun(optarg, &options.tun_remote);
651 if (options.tun_local == SSH_TUNID_ERR) {
652 fprintf(stderr,
653 "Bad tun device '%s'\n", optarg);
654 exit(255);
655 }
656 break;
657 case 'W':
658 if (stdio_forward_host != NULL)
659 fatal("stdio forward already specified");
660 if (muxclient_command != 0)
661 fatal("Cannot specify stdio forward with -O");
662 if (parse_forward(&fwd, optarg, 1, 0)) {
663 stdio_forward_host = fwd.listen_host;
664 stdio_forward_port = fwd.listen_port;
665 free(fwd.connect_host);
666 } else {
667 fprintf(stderr,
668 "Bad stdio forwarding specification '%s'\n",
669 optarg);
670 exit(255);
671 }
672 options.request_tty = REQUEST_TTY_NO;
673 no_shell_flag = 1;
674 options.clear_forwardings = 1;
675 options.exit_on_forward_failure = 1;
676 break;
677 case 'q':
678 options.log_level = SYSLOG_LEVEL_QUIET;
679 break;
680 case 'e':
681 if (optarg[0] == '^' && optarg[2] == 0 &&
682 (u_char) optarg[1] >= 64 &&
683 (u_char) optarg[1] < 128)
684 options.escape_char = (u_char) optarg[1] & 31;
685 else if (strlen(optarg) == 1)
686 options.escape_char = (u_char) optarg[0];
687 else if (strcmp(optarg, "none") == 0)
688 options.escape_char = SSH_ESCAPECHAR_NONE;
689 else {
690 fprintf(stderr, "Bad escape character '%s'.\n",
691 optarg);
692 exit(255);
693 }
694 break;
695 case 'c':
696 if (ciphers_valid(optarg)) {
697 /* SSH2 only */
698 options.ciphers = xstrdup(optarg);
699 options.cipher = SSH_CIPHER_INVALID;
700 } else {
701 /* SSH1 only */
702 options.cipher = cipher_number(optarg);
703 if (options.cipher == -1) {
704 fprintf(stderr,
705 "Unknown cipher type '%s'\n",
706 optarg);
707 exit(255);
708 }
709 if (options.cipher == SSH_CIPHER_3DES)
710 options.ciphers = "3des-cbc";
711 else if (options.cipher == SSH_CIPHER_BLOWFISH)
712 options.ciphers = "blowfish-cbc";
713 else
714 options.ciphers = (char *)-1;
715 }
716 break;
717 case 'm':
718 if (mac_valid(optarg))
719 options.macs = xstrdup(optarg);
720 else {
721 fprintf(stderr, "Unknown mac type '%s'\n",
722 optarg);
723 exit(255);
724 }
725 break;
726 case 'M':
727 if (options.control_master == SSHCTL_MASTER_YES)
728 options.control_master = SSHCTL_MASTER_ASK;
729 else
730 options.control_master = SSHCTL_MASTER_YES;
731 break;
732 case 'p':
733 options.port = a2port(optarg);
734 if (options.port <= 0) {
735 fprintf(stderr, "Bad port '%s'\n", optarg);
736 exit(255);
737 }
738 break;
739 case 'l':
740 options.user = optarg;
741 break;
742
743 case 'L':
744 if (parse_forward(&fwd, optarg, 0, 0))
745 add_local_forward(&options, &fwd);
746 else {
747 fprintf(stderr,
748 "Bad local forwarding specification '%s'\n",
749 optarg);
750 exit(255);
751 }
752 break;
753
754 case 'R':
755 if (parse_forward(&fwd, optarg, 0, 1)) {
756 add_remote_forward(&options, &fwd);
757 } else {
758 fprintf(stderr,
759 "Bad remote forwarding specification "
760 "'%s'\n", optarg);
761 exit(255);
762 }
763 break;
764
765 case 'D':
766 if (parse_forward(&fwd, optarg, 1, 0)) {
767 add_local_forward(&options, &fwd);
768 } else {
769 fprintf(stderr,
770 "Bad dynamic forwarding specification "
771 "'%s'\n", optarg);
772 exit(255);
773 }
774 break;
775
776 case 'C':
777 options.compression = 1;
778 break;
779 case 'N':
780 no_shell_flag = 1;
781 options.request_tty = REQUEST_TTY_NO;
782 break;
783 case 'T':
784 options.request_tty = REQUEST_TTY_NO;
785 break;
786 case 'o':
787 line = xstrdup(optarg);
788 if (process_config_line(&options, pw, host ? host : "",
789 line, "command-line", 0, NULL, SSHCONF_USERCONF)
790 != 0)
791 exit(255);
792 free(line);
793 break;
794 case 's':
795 subsystem_flag = 1;
796 break;
797 case 'S':
798 if (options.control_path != NULL)
799 free(options.control_path);
800 options.control_path = xstrdup(optarg);
801 break;
802 case 'b':
803 options.bind_address = optarg;
804 break;
805 case 'F':
806 config = optarg;
807 break;
808 default:
809 usage();
810 }
811 }
812
813 ac -= optind;
814 av += optind;
815
816 if (ac > 0 && !host) {
817 if (strrchr(*av, '@')) {
818 p = xstrdup(*av);
819 cp = strrchr(p, '@');
820 if (cp == NULL || cp == p)
821 usage();
822 options.user = p;
823 *cp = '\0';
824 host = xstrdup(++cp);
825 } else
826 host = xstrdup(*av);
827 if (ac > 1) {
828 optind = optreset = 1;
829 goto again;
830 }
831 ac--, av++;
832 }
833
834 /* Check that we got a host name. */
835 if (!host)
836 usage();
837
838 host_arg = xstrdup(host);
839
840 OpenSSL_add_all_algorithms();
841 ERR_load_crypto_strings();
842
843 /* Initialize the command to execute on remote host. */
844 buffer_init(&command);
845
846 /*
847 * Save the command to execute on the remote host in a buffer. There
848 * is no limit on the length of the command, except by the maximum
849 * packet size. Also sets the tty flag if there is no command.
850 */
851 if (!ac) {
852 /* No command specified - execute shell on a tty. */
853 if (subsystem_flag) {
854 fprintf(stderr,
855 "You must specify a subsystem to invoke.\n");
856 usage();
857 }
858 } else {
859 /* A command has been specified. Store it into the buffer. */
860 for (i = 0; i < ac; i++) {
861 if (i)
862 buffer_append(&command, " ", 1);
863 buffer_append(&command, av[i], strlen(av[i]));
864 }
865 }
866
867 /* Cannot fork to background if no command. */
868 if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
869 !no_shell_flag)
870 fatal("Cannot fork into background without a command "
871 "to execute.");
872
873 /*
874 * Initialize "log" output. Since we are the client all output
875 * goes to stderr unless otherwise specified by -y or -E.
876 */
877 if (use_syslog && logfile != NULL)
878 fatal("Can't specify both -y and -E");
879 if (logfile != NULL) {
880 log_redirect_stderr_to(logfile);
881 free(logfile);
882 }
883 log_init(argv0,
884 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
885 SYSLOG_FACILITY_USER, !use_syslog);
886
887 if (debug_flag)
888 logit("%s, %s", SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
889
890 /* Parse the configuration files */
891 process_config_files(pw);
892
893 /* Hostname canonicalisation needs a few options filled. */
894 fill_default_options_for_canonicalization(&options);
895
896 /* If the user has replaced the hostname then take it into use now */
897 if (options.hostname != NULL) {
898 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
899 cp = percent_expand(options.hostname,
900 "h", host, (char *)NULL);
901 free(host);
902 host = cp;
903 }
904
905 /* If canonicalization requested then try to apply it */
906 lowercase(host);
907 if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
908 addrs = resolve_canonicalize(&host, options.port);
909
910 /*
911 * If CanonicalizePermittedCNAMEs have been specified but
912 * other canonicalization did not happen (by not being requested
913 * or by failing with fallback) then the hostname may still be changed
914 * as a result of CNAME following.
915 *
916 * Try to resolve the bare hostname name using the system resolver's
917 * usual search rules and then apply the CNAME follow rules.
918 *
919 * Skip the lookup if a ProxyCommand is being used unless the user
920 * has specifically requested canonicalisation for this case via
921 * CanonicalizeHostname=always
922 */
923 if (addrs == NULL && options.num_permitted_cnames != 0 &&
924 (option_clear_or_none(options.proxy_command) ||
925 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
926 if ((addrs = resolve_host(host, options.port, 1,
927 cname, sizeof(cname))) == NULL)
928 cleanup_exit(255); /* resolve_host logs the error */
929 check_follow_cname(&host, cname);
930 }
931
932 /*
933 * If the target hostname has changed as a result of canonicalisation
934 * then re-parse the configuration files as new stanzas may match.
935 */
936 if (strcasecmp(host_arg, host) != 0) {
937 debug("Hostname has changed; re-reading configuration");
938 process_config_files(pw);
939 }
940
941 /* Fill configuration defaults. */
942 fill_default_options(&options);
943
944 if (options.port == 0)
945 options.port = default_ssh_port();
946 channel_set_af(options.address_family);
947
948 /* Tidy and check options */
949 if (options.host_key_alias != NULL)
950 lowercase(options.host_key_alias);
951 if (options.proxy_command != NULL &&
952 strcmp(options.proxy_command, "-") == 0 &&
953 options.proxy_use_fdpass)
954 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
955 #ifndef HAVE_CYGWIN
956 if (original_effective_uid != 0)
957 options.use_privileged_port = 0;
958 #endif
959
960 /* reinit */
961 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
962
963 if (options.request_tty == REQUEST_TTY_YES ||
964 options.request_tty == REQUEST_TTY_FORCE)
965 tty_flag = 1;
966
967 /* Allocate a tty by default if no command specified. */
968 if (buffer_len(&command) == 0)
969 tty_flag = options.request_tty != REQUEST_TTY_NO;
970
971 /* Force no tty */
972 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
973 tty_flag = 0;
974 /* Do not allocate a tty if stdin is not a tty. */
975 if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
976 options.request_tty != REQUEST_TTY_FORCE) {
977 if (tty_flag)
978 logit("Pseudo-terminal will not be allocated because "
979 "stdin is not a terminal.");
980 tty_flag = 0;
981 }
982
983 seed_rng();
984
985 if (options.user == NULL)
986 options.user = xstrdup(pw->pw_name);
987
988 if (gethostname(thishost, sizeof(thishost)) == -1)
989 fatal("gethostname: %s", strerror(errno));
990 strlcpy(shorthost, thishost, sizeof(shorthost));
991 shorthost[strcspn(thishost, ".")] = '\0';
992 snprintf(portstr, sizeof(portstr), "%d", options.port);
993
994 /* Find canonic host name. */
995 if (strchr(host, '.') == 0) {
996 struct addrinfo hints;
997 struct addrinfo *ai = NULL;
998 int errgai;
999 memset(&hints, 0, sizeof(hints));
1000 hints.ai_family = options.address_family;
1001 hints.ai_flags = AI_CANONNAME;
1002 hints.ai_socktype = SOCK_STREAM;
1003 errgai = getaddrinfo(host, NULL, &hints, &ai);
1004 if (errgai == 0) {
1005 if (ai->ai_canonname != NULL)
1006 host = xstrdup(ai->ai_canonname);
1007 freeaddrinfo(ai);
1008 }
1009 }
1010
1011 if (options.local_command != NULL) {
1012 debug3("expanding LocalCommand: %s", options.local_command);
1013 cp = options.local_command;
1014 options.local_command = percent_expand(cp, "d", pw->pw_dir,
1015 "h", host, "l", thishost, "n", host_arg, "r", options.user,
1016 "p", portstr, "u", pw->pw_name, "L", shorthost,
1017 (char *)NULL);
1018 debug3("expanded LocalCommand: %s", options.local_command);
1019 free(cp);
1020 }
1021
1022 if (options.control_path != NULL) {
1023 cp = tilde_expand_filename(options.control_path,
1024 original_real_uid);
1025 free(options.control_path);
1026 options.control_path = percent_expand(cp, "h", host,
1027 "l", thishost, "n", host_arg, "r", options.user,
1028 "p", portstr, "u", pw->pw_name, "L", shorthost,
1029 (char *)NULL);
1030 free(cp);
1031 }
1032 if (muxclient_command != 0 && options.control_path == NULL)
1033 fatal("No ControlPath specified for \"-O\" command");
1034 if (options.control_path != NULL)
1035 muxclient(options.control_path);
1036
1037 /*
1038 * If hostname canonicalisation was not enabled, then we may not
1039 * have yet resolved the hostname. Do so now.
1040 */
1041 if (addrs == NULL && options.proxy_command == NULL) {
1042 if ((addrs = resolve_host(host, options.port, 1,
1043 cname, sizeof(cname))) == NULL)
1044 cleanup_exit(255); /* resolve_host logs the error */
1045 }
1046
1047 timeout_ms = options.connection_timeout * 1000;
1048
1049 /* Open a connection to the remote host. */
1050 if (ssh_connect(host, addrs, &hostaddr, options.port,
1051 options.address_family, options.connection_attempts,
1052 &timeout_ms, options.tcp_keep_alive,
1053 options.use_privileged_port) != 0)
1054 exit(255);
1055
1056 if (addrs != NULL)
1057 freeaddrinfo(addrs);
1058
1059 packet_set_timeout(options.server_alive_interval,
1060 options.server_alive_count_max);
1061
1062 if (timeout_ms > 0)
1063 debug3("timeout: %d ms remain after connect", timeout_ms);
1064
1065 /*
1066 * If we successfully made the connection, load the host private key
1067 * in case we will need it later for combined rsa-rhosts
1068 * authentication. This must be done before releasing extra
1069 * privileges, because the file is only readable by root.
1070 * If we cannot access the private keys, load the public keys
1071 * instead and try to execute the ssh-keysign helper instead.
1072 */
1073 sensitive_data.nkeys = 0;
1074 sensitive_data.keys = NULL;
1075 sensitive_data.external_keysign = 0;
1076 if (options.rhosts_rsa_authentication ||
1077 options.hostbased_authentication) {
1078 sensitive_data.nkeys = 9;
1079 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1080 sizeof(Key));
1081 for (i = 0; i < sensitive_data.nkeys; i++)
1082 sensitive_data.keys[i] = NULL;
1083
1084 PRIV_START;
1085 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1086 _PATH_HOST_KEY_FILE, "", NULL, NULL);
1087 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
1088 _PATH_HOST_DSA_KEY_FILE, "", NULL);
1089 #ifdef OPENSSL_HAS_ECC
1090 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
1091 _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1092 #endif
1093 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1094 _PATH_HOST_RSA_KEY_FILE, "", NULL);
1095 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519,
1096 _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1097 sensitive_data.keys[5] = key_load_private_type(KEY_DSA,
1098 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1099 #ifdef OPENSSL_HAS_ECC
1100 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA,
1101 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1102 #endif
1103 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1104 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1105 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519,
1106 _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1107 PRIV_END;
1108
1109 if (options.hostbased_authentication == 1 &&
1110 sensitive_data.keys[0] == NULL &&
1111 sensitive_data.keys[5] == NULL &&
1112 sensitive_data.keys[6] == NULL &&
1113 sensitive_data.keys[7] == NULL &&
1114 sensitive_data.keys[8] == NULL) {
1115 sensitive_data.keys[1] = key_load_cert(
1116 _PATH_HOST_DSA_KEY_FILE);
1117 #ifdef OPENSSL_HAS_ECC
1118 sensitive_data.keys[2] = key_load_cert(
1119 _PATH_HOST_ECDSA_KEY_FILE);
1120 #endif
1121 sensitive_data.keys[3] = key_load_cert(
1122 _PATH_HOST_RSA_KEY_FILE);
1123 sensitive_data.keys[4] = key_load_cert(
1124 _PATH_HOST_ED25519_KEY_FILE);
1125 sensitive_data.keys[5] = key_load_public(
1126 _PATH_HOST_DSA_KEY_FILE, NULL);
1127 #ifdef OPENSSL_HAS_ECC
1128 sensitive_data.keys[6] = key_load_public(
1129 _PATH_HOST_ECDSA_KEY_FILE, NULL);
1130 #endif
1131 sensitive_data.keys[7] = key_load_public(
1132 _PATH_HOST_RSA_KEY_FILE, NULL);
1133 sensitive_data.keys[8] = key_load_public(
1134 _PATH_HOST_ED25519_KEY_FILE, NULL);
1135 sensitive_data.external_keysign = 1;
1136 }
1137 }
1138 /*
1139 * Get rid of any extra privileges that we may have. We will no
1140 * longer need them. Also, extra privileges could make it very hard
1141 * to read identity files and other non-world-readable files from the
1142 * user's home directory if it happens to be on a NFS volume where
1143 * root is mapped to nobody.
1144 */
1145 if (original_effective_uid == 0) {
1146 PRIV_START;
1147 permanently_set_uid(pw);
1148 }
1149
1150 /*
1151 * Now that we are back to our own permissions, create ~/.ssh
1152 * directory if it doesn't already exist.
1153 */
1154 if (config == NULL) {
1155 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1156 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1157 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1158 #ifdef WITH_SELINUX
1159 ssh_selinux_setfscreatecon(buf);
1160 #endif
1161 if (mkdir(buf, 0700) < 0)
1162 error("Could not create directory '%.200s'.",
1163 buf);
1164 #ifdef WITH_SELINUX
1165 ssh_selinux_setfscreatecon(NULL);
1166 #endif
1167 }
1168 }
1169 /* load options.identity_files */
1170 load_public_identity_files();
1171
1172 /* Expand ~ in known host file names. */
1173 tilde_expand_paths(options.system_hostfiles,
1174 options.num_system_hostfiles);
1175 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1176
1177 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1178 signal(SIGCHLD, main_sigchld_handler);
1179
1180 /* Log into the remote system. Never returns if the login fails. */
1181 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1182 options.port, pw, timeout_ms);
1183
1184 if (packet_connection_is_on_socket()) {
1185 verbose("Authenticated to %s ([%s]:%d).", host,
1186 get_remote_ipaddr(), get_remote_port());
1187 } else {
1188 verbose("Authenticated to %s (via proxy).", host);
1189 }
1190
1191 /* We no longer need the private host keys. Clear them now. */
1192 if (sensitive_data.nkeys != 0) {
1193 for (i = 0; i < sensitive_data.nkeys; i++) {
1194 if (sensitive_data.keys[i] != NULL) {
1195 /* Destroys contents safely */
1196 debug3("clear hostkey %d", i);
1197 key_free(sensitive_data.keys[i]);
1198 sensitive_data.keys[i] = NULL;
1199 }
1200 }
1201 free(sensitive_data.keys);
1202 }
1203 for (i = 0; i < options.num_identity_files; i++) {
1204 free(options.identity_files[i]);
1205 options.identity_files[i] = NULL;
1206 if (options.identity_keys[i]) {
1207 key_free(options.identity_keys[i]);
1208 options.identity_keys[i] = NULL;
1209 }
1210 }
1211
1212 exit_status = compat20 ? ssh_session2() : ssh_session();
1213 packet_close();
1214
1215 if (options.control_path != NULL && muxserver_sock != -1)
1216 unlink(options.control_path);
1217
1218 /* Kill ProxyCommand if it is running. */
1219 ssh_kill_proxy_command();
1220
1221 return exit_status;
1222 }
1223
1224 static void
control_persist_detach(void)1225 control_persist_detach(void)
1226 {
1227 pid_t pid;
1228 int devnull;
1229
1230 debug("%s: backgrounding master process", __func__);
1231
1232 /*
1233 * master (current process) into the background, and make the
1234 * foreground process a client of the backgrounded master.
1235 */
1236 switch ((pid = fork())) {
1237 case -1:
1238 fatal("%s: fork: %s", __func__, strerror(errno));
1239 case 0:
1240 /* Child: master process continues mainloop */
1241 break;
1242 default:
1243 /* Parent: set up mux slave to connect to backgrounded master */
1244 debug2("%s: background process is %ld", __func__, (long)pid);
1245 stdin_null_flag = ostdin_null_flag;
1246 options.request_tty = orequest_tty;
1247 tty_flag = otty_flag;
1248 close(muxserver_sock);
1249 muxserver_sock = -1;
1250 options.control_master = SSHCTL_MASTER_NO;
1251 muxclient(options.control_path);
1252 /* muxclient() doesn't return on success. */
1253 fatal("Failed to connect to new control master");
1254 }
1255 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1256 error("%s: open(\"/dev/null\"): %s", __func__,
1257 strerror(errno));
1258 } else {
1259 if (dup2(devnull, STDIN_FILENO) == -1 ||
1260 dup2(devnull, STDOUT_FILENO) == -1)
1261 error("%s: dup2: %s", __func__, strerror(errno));
1262 if (devnull > STDERR_FILENO)
1263 close(devnull);
1264 }
1265 daemon(1, 1);
1266 setproctitle("%s [mux]", options.control_path);
1267 }
1268
1269 /* Do fork() after authentication. Used by "ssh -f" */
1270 static void
fork_postauth(void)1271 fork_postauth(void)
1272 {
1273 if (need_controlpersist_detach)
1274 control_persist_detach();
1275 debug("forking to background");
1276 fork_after_authentication_flag = 0;
1277 if (daemon(1, 1) < 0)
1278 fatal("daemon() failed: %.200s", strerror(errno));
1279 }
1280
1281 /* Callback for remote forward global requests */
1282 static void
ssh_confirm_remote_forward(int type,u_int32_t seq,void * ctxt)1283 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1284 {
1285 Forward *rfwd = (Forward *)ctxt;
1286
1287 /* XXX verbose() on failure? */
1288 debug("remote forward %s for: listen %d, connect %s:%d",
1289 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1290 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
1291 if (rfwd->listen_port == 0) {
1292 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1293 rfwd->allocated_port = packet_get_int();
1294 logit("Allocated port %u for remote forward to %s:%d",
1295 rfwd->allocated_port,
1296 rfwd->connect_host, rfwd->connect_port);
1297 channel_update_permitted_opens(rfwd->handle,
1298 rfwd->allocated_port);
1299 } else {
1300 channel_update_permitted_opens(rfwd->handle, -1);
1301 }
1302 }
1303
1304 if (type == SSH2_MSG_REQUEST_FAILURE) {
1305 if (options.exit_on_forward_failure)
1306 fatal("Error: remote port forwarding failed for "
1307 "listen port %d", rfwd->listen_port);
1308 else
1309 logit("Warning: remote port forwarding failed for "
1310 "listen port %d", rfwd->listen_port);
1311 }
1312 if (++remote_forward_confirms_received == options.num_remote_forwards) {
1313 debug("All remote forwarding requests processed");
1314 if (fork_after_authentication_flag)
1315 fork_postauth();
1316 }
1317 }
1318
1319 static void
client_cleanup_stdio_fwd(int id,void * arg)1320 client_cleanup_stdio_fwd(int id, void *arg)
1321 {
1322 debug("stdio forwarding: done");
1323 cleanup_exit(0);
1324 }
1325
1326 static void
ssh_init_stdio_forwarding(void)1327 ssh_init_stdio_forwarding(void)
1328 {
1329 Channel *c;
1330 int in, out;
1331
1332 if (stdio_forward_host == NULL)
1333 return;
1334 if (!compat20)
1335 fatal("stdio forwarding require Protocol 2");
1336
1337 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1338
1339 if ((in = dup(STDIN_FILENO)) < 0 ||
1340 (out = dup(STDOUT_FILENO)) < 0)
1341 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1342 if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1343 stdio_forward_port, in, out)) == NULL)
1344 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1345 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1346 }
1347
1348 static void
ssh_init_forwarding(void)1349 ssh_init_forwarding(void)
1350 {
1351 int success = 0;
1352 int i;
1353
1354 /* Initiate local TCP/IP port forwardings. */
1355 for (i = 0; i < options.num_local_forwards; i++) {
1356 debug("Local connections to %.200s:%d forwarded to remote "
1357 "address %.200s:%d",
1358 (options.local_forwards[i].listen_host == NULL) ?
1359 (options.gateway_ports ? "*" : "LOCALHOST") :
1360 options.local_forwards[i].listen_host,
1361 options.local_forwards[i].listen_port,
1362 options.local_forwards[i].connect_host,
1363 options.local_forwards[i].connect_port);
1364 success += channel_setup_local_fwd_listener(
1365 options.local_forwards[i].listen_host,
1366 options.local_forwards[i].listen_port,
1367 options.local_forwards[i].connect_host,
1368 options.local_forwards[i].connect_port,
1369 options.gateway_ports);
1370 }
1371 if (i > 0 && success != i && options.exit_on_forward_failure)
1372 fatal("Could not request local forwarding.");
1373 if (i > 0 && success == 0)
1374 error("Could not request local forwarding.");
1375
1376 /* Initiate remote TCP/IP port forwardings. */
1377 for (i = 0; i < options.num_remote_forwards; i++) {
1378 debug("Remote connections from %.200s:%d forwarded to "
1379 "local address %.200s:%d",
1380 (options.remote_forwards[i].listen_host == NULL) ?
1381 "LOCALHOST" : options.remote_forwards[i].listen_host,
1382 options.remote_forwards[i].listen_port,
1383 options.remote_forwards[i].connect_host,
1384 options.remote_forwards[i].connect_port);
1385 options.remote_forwards[i].handle =
1386 channel_request_remote_forwarding(
1387 options.remote_forwards[i].listen_host,
1388 options.remote_forwards[i].listen_port,
1389 options.remote_forwards[i].connect_host,
1390 options.remote_forwards[i].connect_port);
1391 if (options.remote_forwards[i].handle < 0) {
1392 if (options.exit_on_forward_failure)
1393 fatal("Could not request remote forwarding.");
1394 else
1395 logit("Warning: Could not request remote "
1396 "forwarding.");
1397 } else {
1398 client_register_global_confirm(ssh_confirm_remote_forward,
1399 &options.remote_forwards[i]);
1400 }
1401 }
1402
1403 /* Initiate tunnel forwarding. */
1404 if (options.tun_open != SSH_TUNMODE_NO) {
1405 if (client_request_tun_fwd(options.tun_open,
1406 options.tun_local, options.tun_remote) == -1) {
1407 if (options.exit_on_forward_failure)
1408 fatal("Could not request tunnel forwarding.");
1409 else
1410 error("Could not request tunnel forwarding.");
1411 }
1412 }
1413 }
1414
1415 static void
check_agent_present(void)1416 check_agent_present(void)
1417 {
1418 if (options.forward_agent) {
1419 /* Clear agent forwarding if we don't have an agent. */
1420 if (!ssh_agent_present())
1421 options.forward_agent = 0;
1422 }
1423 }
1424
1425 static int
ssh_session(void)1426 ssh_session(void)
1427 {
1428 int type;
1429 int interactive = 0;
1430 int have_tty = 0;
1431 struct winsize ws;
1432 char *cp;
1433 const char *display;
1434
1435 /* Enable compression if requested. */
1436 if (options.compression) {
1437 debug("Requesting compression at level %d.",
1438 options.compression_level);
1439
1440 if (options.compression_level < 1 ||
1441 options.compression_level > 9)
1442 fatal("Compression level must be from 1 (fast) to "
1443 "9 (slow, best).");
1444
1445 /* Send the request. */
1446 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1447 packet_put_int(options.compression_level);
1448 packet_send();
1449 packet_write_wait();
1450 type = packet_read();
1451 if (type == SSH_SMSG_SUCCESS)
1452 packet_start_compression(options.compression_level);
1453 else if (type == SSH_SMSG_FAILURE)
1454 logit("Warning: Remote host refused compression.");
1455 else
1456 packet_disconnect("Protocol error waiting for "
1457 "compression response.");
1458 }
1459 /* Allocate a pseudo tty if appropriate. */
1460 if (tty_flag) {
1461 debug("Requesting pty.");
1462
1463 /* Start the packet. */
1464 packet_start(SSH_CMSG_REQUEST_PTY);
1465
1466 /* Store TERM in the packet. There is no limit on the
1467 length of the string. */
1468 cp = getenv("TERM");
1469 if (!cp)
1470 cp = "";
1471 packet_put_cstring(cp);
1472
1473 /* Store window size in the packet. */
1474 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1475 memset(&ws, 0, sizeof(ws));
1476 packet_put_int((u_int)ws.ws_row);
1477 packet_put_int((u_int)ws.ws_col);
1478 packet_put_int((u_int)ws.ws_xpixel);
1479 packet_put_int((u_int)ws.ws_ypixel);
1480
1481 /* Store tty modes in the packet. */
1482 tty_make_modes(fileno(stdin), NULL);
1483
1484 /* Send the packet, and wait for it to leave. */
1485 packet_send();
1486 packet_write_wait();
1487
1488 /* Read response from the server. */
1489 type = packet_read();
1490 if (type == SSH_SMSG_SUCCESS) {
1491 interactive = 1;
1492 have_tty = 1;
1493 } else if (type == SSH_SMSG_FAILURE)
1494 logit("Warning: Remote host failed or refused to "
1495 "allocate a pseudo tty.");
1496 else
1497 packet_disconnect("Protocol error waiting for pty "
1498 "request response.");
1499 }
1500 /* Request X11 forwarding if enabled and DISPLAY is set. */
1501 display = getenv("DISPLAY");
1502 if (options.forward_x11 && display != NULL) {
1503 char *proto, *data;
1504 /* Get reasonable local authentication information. */
1505 client_x11_get_proto(display, options.xauth_location,
1506 options.forward_x11_trusted,
1507 options.forward_x11_timeout,
1508 &proto, &data);
1509 /* Request forwarding with authentication spoofing. */
1510 debug("Requesting X11 forwarding with authentication "
1511 "spoofing.");
1512 x11_request_forwarding_with_spoofing(0, display, proto,
1513 data, 0);
1514 /* Read response from the server. */
1515 type = packet_read();
1516 if (type == SSH_SMSG_SUCCESS) {
1517 interactive = 1;
1518 } else if (type == SSH_SMSG_FAILURE) {
1519 logit("Warning: Remote host denied X11 forwarding.");
1520 } else {
1521 packet_disconnect("Protocol error waiting for X11 "
1522 "forwarding");
1523 }
1524 }
1525 /* Tell the packet module whether this is an interactive session. */
1526 packet_set_interactive(interactive,
1527 options.ip_qos_interactive, options.ip_qos_bulk);
1528
1529 /* Request authentication agent forwarding if appropriate. */
1530 check_agent_present();
1531
1532 if (options.forward_agent) {
1533 debug("Requesting authentication agent forwarding.");
1534 auth_request_forwarding();
1535
1536 /* Read response from the server. */
1537 type = packet_read();
1538 packet_check_eom();
1539 if (type != SSH_SMSG_SUCCESS)
1540 logit("Warning: Remote host denied authentication agent forwarding.");
1541 }
1542
1543 /* Initiate port forwardings. */
1544 ssh_init_stdio_forwarding();
1545 ssh_init_forwarding();
1546
1547 /* Execute a local command */
1548 if (options.local_command != NULL &&
1549 options.permit_local_command)
1550 ssh_local_cmd(options.local_command);
1551
1552 /*
1553 * If requested and we are not interested in replies to remote
1554 * forwarding requests, then let ssh continue in the background.
1555 */
1556 if (fork_after_authentication_flag) {
1557 if (options.exit_on_forward_failure &&
1558 options.num_remote_forwards > 0) {
1559 debug("deferring postauth fork until remote forward "
1560 "confirmation received");
1561 } else
1562 fork_postauth();
1563 }
1564
1565 /*
1566 * If a command was specified on the command line, execute the
1567 * command now. Otherwise request the server to start a shell.
1568 */
1569 if (buffer_len(&command) > 0) {
1570 int len = buffer_len(&command);
1571 if (len > 900)
1572 len = 900;
1573 debug("Sending command: %.*s", len,
1574 (u_char *)buffer_ptr(&command));
1575 packet_start(SSH_CMSG_EXEC_CMD);
1576 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1577 packet_send();
1578 packet_write_wait();
1579 } else {
1580 debug("Requesting shell.");
1581 packet_start(SSH_CMSG_EXEC_SHELL);
1582 packet_send();
1583 packet_write_wait();
1584 }
1585
1586 /* Enter the interactive session. */
1587 return client_loop(have_tty, tty_flag ?
1588 options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1589 }
1590
1591 /* request pty/x11/agent/tcpfwd/shell for channel */
1592 static void
ssh_session2_setup(int id,int success,void * arg)1593 ssh_session2_setup(int id, int success, void *arg)
1594 {
1595 extern char **environ;
1596 const char *display;
1597 int interactive = tty_flag;
1598
1599 if (!success)
1600 return; /* No need for error message, channels code sens one */
1601
1602 display = getenv("DISPLAY");
1603 if (options.forward_x11 && display != NULL) {
1604 char *proto, *data;
1605 /* Get reasonable local authentication information. */
1606 client_x11_get_proto(display, options.xauth_location,
1607 options.forward_x11_trusted,
1608 options.forward_x11_timeout, &proto, &data);
1609 /* Request forwarding with authentication spoofing. */
1610 debug("Requesting X11 forwarding with authentication "
1611 "spoofing.");
1612 x11_request_forwarding_with_spoofing(id, display, proto,
1613 data, 1);
1614 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1615 /* XXX exit_on_forward_failure */
1616 interactive = 1;
1617 }
1618
1619 check_agent_present();
1620 if (options.forward_agent) {
1621 debug("Requesting authentication agent forwarding.");
1622 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1623 packet_send();
1624 }
1625
1626 /* Tell the packet module whether this is an interactive session. */
1627 packet_set_interactive(interactive,
1628 options.ip_qos_interactive, options.ip_qos_bulk);
1629
1630 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1631 NULL, fileno(stdin), &command, environ);
1632 }
1633
1634 /* open new channel for a session */
1635 static int
ssh_session2_open(void)1636 ssh_session2_open(void)
1637 {
1638 Channel *c;
1639 int window, packetmax, in, out, err;
1640
1641 if (stdin_null_flag) {
1642 in = open(_PATH_DEVNULL, O_RDONLY);
1643 } else {
1644 in = dup(STDIN_FILENO);
1645 }
1646 out = dup(STDOUT_FILENO);
1647 err = dup(STDERR_FILENO);
1648
1649 if (in < 0 || out < 0 || err < 0)
1650 fatal("dup() in/out/err failed");
1651
1652 /* enable nonblocking unless tty */
1653 if (!isatty(in))
1654 set_nonblock(in);
1655 if (!isatty(out))
1656 set_nonblock(out);
1657 if (!isatty(err))
1658 set_nonblock(err);
1659
1660 /*
1661 * We need to check to see what to do about buffer sizes here.
1662 * - In an HPN to non-HPN connection we want to limit the window size to
1663 * something reasonable in case the far side has the large window bug.
1664 * - In an HPN to HPN connection we want to use the max window size but
1665 * allow the user to override it.
1666 * - Lastly if HPN is disabled then use the ssh standard window size.
1667 *
1668 * We cannot just do a getsockopt() here and set the ssh window to that
1669 * as in case of autotuning of socket buffers the window would get stuck
1670 * at the initial buffer size, generally less than 96k. Therefore we
1671 * need to set the maximum ssh window size to the maximum HPN buffer
1672 * size unless the user has set TcpRcvBufPoll to no. In that case we
1673 * can just set the window to the minimum of HPN buffer size and TCP
1674 * receive buffer size.
1675 */
1676 if (tty_flag)
1677 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1678 else
1679 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT;
1680
1681 if (datafellows & SSH_BUG_LARGEWINDOW) {
1682 debug("HPN to Non-HPN Connection");
1683 } else if (options.tcp_rcv_buf_poll <= 0) {
1684 sock_get_rcvbuf(&options.hpn_buffer_size, 0);
1685 debug("HPNBufferSize set to TCP RWIN: %d",
1686 options.hpn_buffer_size);
1687 } else if (options.tcp_rcv_buf > 0) {
1688 sock_get_rcvbuf(&options.hpn_buffer_size,
1689 options.tcp_rcv_buf);
1690 debug("HPNBufferSize set to user TCPRcvBuf: %d",
1691 options.hpn_buffer_size);
1692 }
1693 debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1694 channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1695 window = options.hpn_buffer_size;
1696
1697 packetmax = CHAN_SES_PACKET_DEFAULT;
1698 if (tty_flag) {
1699 window = CHAN_SES_WINDOW_DEFAULT;
1700 window >>= 1;
1701 packetmax >>= 1;
1702 }
1703 c = channel_new(
1704 "session", SSH_CHANNEL_OPENING, in, out, err,
1705 window, packetmax, CHAN_EXTENDED_WRITE,
1706 "client-session", /*nonblock*/0);
1707 if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) {
1708 c->dynamic_window = 1;
1709 debug("Enabled Dynamic Window Scaling\n");
1710 }
1711
1712 debug3("ssh_session2_open: channel_new: %d", c->self);
1713
1714 channel_send_open(c->self);
1715 if (!no_shell_flag)
1716 channel_register_open_confirm(c->self,
1717 ssh_session2_setup, NULL);
1718
1719 return c->self;
1720 }
1721
1722 static int
ssh_session2(void)1723 ssh_session2(void)
1724 {
1725 int id = -1;
1726
1727 /* XXX should be pre-session */
1728 if (!options.control_persist)
1729 ssh_init_stdio_forwarding();
1730 ssh_init_forwarding();
1731
1732 /* Start listening for multiplex clients */
1733 muxserver_listen();
1734
1735 /*
1736 * If we are in control persist mode and have a working mux listen
1737 * socket, then prepare to background ourselves and have a foreground
1738 * client attach as a control slave.
1739 * NB. we must save copies of the flags that we override for
1740 * the backgrounding, since we defer attachment of the slave until
1741 * after the connection is fully established (in particular,
1742 * async rfwd replies have been received for ExitOnForwardFailure).
1743 */
1744 if (options.control_persist && muxserver_sock != -1) {
1745 ostdin_null_flag = stdin_null_flag;
1746 ono_shell_flag = no_shell_flag;
1747 orequest_tty = options.request_tty;
1748 otty_flag = tty_flag;
1749 stdin_null_flag = 1;
1750 no_shell_flag = 1;
1751 tty_flag = 0;
1752 if (!fork_after_authentication_flag)
1753 need_controlpersist_detach = 1;
1754 fork_after_authentication_flag = 1;
1755 }
1756 /*
1757 * ControlPersist mux listen socket setup failed, attempt the
1758 * stdio forward setup that we skipped earlier.
1759 */
1760 if (options.control_persist && muxserver_sock == -1)
1761 ssh_init_stdio_forwarding();
1762
1763 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1764 id = ssh_session2_open();
1765 else {
1766 packet_set_interactive(
1767 options.control_master == SSHCTL_MASTER_NO,
1768 options.ip_qos_interactive, options.ip_qos_bulk);
1769 }
1770
1771 /* If we don't expect to open a new session, then disallow it */
1772 if (options.control_master == SSHCTL_MASTER_NO &&
1773 (datafellows & SSH_NEW_OPENSSH)) {
1774 debug("Requesting no-more-sessions@openssh.com");
1775 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1776 packet_put_cstring("no-more-sessions@openssh.com");
1777 packet_put_char(0);
1778 packet_send();
1779 }
1780
1781 /* Execute a local command */
1782 if (options.local_command != NULL &&
1783 options.permit_local_command)
1784 ssh_local_cmd(options.local_command);
1785
1786 /*
1787 * If requested and we are not interested in replies to remote
1788 * forwarding requests, then let ssh continue in the background.
1789 */
1790 if (fork_after_authentication_flag) {
1791 if (options.exit_on_forward_failure &&
1792 options.num_remote_forwards > 0) {
1793 debug("deferring postauth fork until remote forward "
1794 "confirmation received");
1795 } else
1796 fork_postauth();
1797 }
1798
1799 if (options.use_roaming)
1800 request_roaming();
1801
1802 return client_loop(tty_flag, tty_flag ?
1803 options.escape_char : SSH_ESCAPECHAR_NONE, id);
1804 }
1805
1806 static void
load_public_identity_files(void)1807 load_public_identity_files(void)
1808 {
1809 char *filename, *cp, thishost[NI_MAXHOST];
1810 char *pwdir = NULL, *pwname = NULL;
1811 int i = 0;
1812 Key *public;
1813 struct passwd *pw;
1814 u_int n_ids;
1815 char *identity_files[SSH_MAX_IDENTITY_FILES];
1816 Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1817 #ifdef ENABLE_PKCS11
1818 Key **keys;
1819 int nkeys;
1820 #endif /* PKCS11 */
1821
1822 n_ids = 0;
1823 memset(identity_files, 0, sizeof(identity_files));
1824 memset(identity_keys, 0, sizeof(identity_keys));
1825
1826 #ifdef ENABLE_PKCS11
1827 if (options.pkcs11_provider != NULL &&
1828 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1829 (pkcs11_init(!options.batch_mode) == 0) &&
1830 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1831 &keys)) > 0) {
1832 for (i = 0; i < nkeys; i++) {
1833 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1834 key_free(keys[i]);
1835 continue;
1836 }
1837 identity_keys[n_ids] = keys[i];
1838 identity_files[n_ids] =
1839 xstrdup(options.pkcs11_provider); /* XXX */
1840 n_ids++;
1841 }
1842 free(keys);
1843 }
1844 #endif /* ENABLE_PKCS11 */
1845 if ((pw = getpwuid(original_real_uid)) == NULL)
1846 fatal("load_public_identity_files: getpwuid failed");
1847 pwname = xstrdup(pw->pw_name);
1848 pwdir = xstrdup(pw->pw_dir);
1849 if (gethostname(thishost, sizeof(thishost)) == -1)
1850 fatal("load_public_identity_files: gethostname: %s",
1851 strerror(errno));
1852 for (i = 0; i < options.num_identity_files; i++) {
1853 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
1854 strcasecmp(options.identity_files[i], "none") == 0) {
1855 free(options.identity_files[i]);
1856 continue;
1857 }
1858 cp = tilde_expand_filename(options.identity_files[i],
1859 original_real_uid);
1860 filename = percent_expand(cp, "d", pwdir,
1861 "u", pwname, "l", thishost, "h", host,
1862 "r", options.user, (char *)NULL);
1863 free(cp);
1864 public = key_load_public(filename, NULL);
1865 debug("identity file %s type %d", filename,
1866 public ? public->type : -1);
1867 free(options.identity_files[i]);
1868 identity_files[n_ids] = filename;
1869 identity_keys[n_ids] = public;
1870
1871 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1872 continue;
1873
1874 /* Try to add the certificate variant too */
1875 xasprintf(&cp, "%s-cert", filename);
1876 public = key_load_public(cp, NULL);
1877 debug("identity file %s type %d", cp,
1878 public ? public->type : -1);
1879 if (public == NULL) {
1880 free(cp);
1881 continue;
1882 }
1883 if (!key_is_cert(public)) {
1884 debug("%s: key %s type %s is not a certificate",
1885 __func__, cp, key_type(public));
1886 key_free(public);
1887 free(cp);
1888 continue;
1889 }
1890 identity_keys[n_ids] = public;
1891 /* point to the original path, most likely the private key */
1892 identity_files[n_ids] = xstrdup(filename);
1893 n_ids++;
1894 }
1895 options.num_identity_files = n_ids;
1896 memcpy(options.identity_files, identity_files, sizeof(identity_files));
1897 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1898
1899 explicit_bzero(pwname, strlen(pwname));
1900 free(pwname);
1901 explicit_bzero(pwdir, strlen(pwdir));
1902 free(pwdir);
1903 }
1904
1905 static void
main_sigchld_handler(int sig)1906 main_sigchld_handler(int sig)
1907 {
1908 int save_errno = errno;
1909 pid_t pid;
1910 int status;
1911
1912 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1913 (pid < 0 && errno == EINTR))
1914 ;
1915
1916 signal(sig, main_sigchld_handler);
1917 errno = save_errno;
1918 }
1919