1 /* $OpenBSD: ssh.c,v 1.401 2014/02/26 20:18:37 djm Exp $ */
2 /* $FreeBSD$ */
3 /*
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * All rights reserved
7 * Ssh client program. This program can be used to log into a remote machine.
8 * The software supports strong authentication, encryption, and forwarding
9 * of X11, TCP/IP, and authentication connections.
10 *
11 * As far as I am concerned, the code I have written for this software
12 * can be used freely for any purpose. Any derived versions of this
13 * software must be clearly marked as such, and if the derived work is
14 * incompatible with the protocol description in the RFC file, it must be
15 * called by a name other than "ssh" or "Secure Shell".
16 *
17 * Copyright (c) 1999 Niels Provos. All rights reserved.
18 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved.
19 *
20 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
21 * in Canada (German citizen).
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the above copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
33 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
35 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
36 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
41 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 #include "includes.h"
45 __RCSID("$FreeBSD$");
46
47 #include <sys/types.h>
48 #ifdef HAVE_SYS_STAT_H
49 # include <sys/stat.h>
50 #endif
51 #include <sys/resource.h>
52 #include <sys/ioctl.h>
53 #include <sys/param.h>
54 #include <sys/socket.h>
55 #include <sys/wait.h>
56
57 #include <ctype.h>
58 #include <errno.h>
59 #include <fcntl.h>
60 #include <netdb.h>
61 #ifdef HAVE_PATHS_H
62 #include <paths.h>
63 #endif
64 #include <pwd.h>
65 #include <signal.h>
66 #include <stdarg.h>
67 #include <stddef.h>
68 #include <stdio.h>
69 #include <stdlib.h>
70 #include <string.h>
71 #include <unistd.h>
72
73 #include <netinet/in.h>
74 #include <arpa/inet.h>
75
76 #include <openssl/evp.h>
77 #include <openssl/err.h>
78 #include "openbsd-compat/openssl-compat.h"
79 #include "openbsd-compat/sys-queue.h"
80
81 #include "xmalloc.h"
82 #include "ssh.h"
83 #include "ssh1.h"
84 #include "ssh2.h"
85 #include "canohost.h"
86 #include "compat.h"
87 #include "cipher.h"
88 #include "packet.h"
89 #include "buffer.h"
90 #include "channels.h"
91 #include "key.h"
92 #include "authfd.h"
93 #include "authfile.h"
94 #include "pathnames.h"
95 #include "dispatch.h"
96 #include "clientloop.h"
97 #include "log.h"
98 #include "readconf.h"
99 #include "sshconnect.h"
100 #include "misc.h"
101 #include "kex.h"
102 #include "mac.h"
103 #include "sshpty.h"
104 #include "match.h"
105 #include "msg.h"
106 #include "uidswap.h"
107 #include "roaming.h"
108 #include "version.h"
109
110 #ifdef ENABLE_PKCS11
111 #include "ssh-pkcs11.h"
112 #endif
113
114 extern char *__progname;
115
116 /* Saves a copy of argv for setproctitle emulation */
117 #ifndef HAVE_SETPROCTITLE
118 static char **saved_av;
119 #endif
120
121 /* Flag indicating whether debug mode is on. May be set on the command line. */
122 int debug_flag = 0;
123
124 /* Flag indicating whether a tty should be requested */
125 int tty_flag = 0;
126
127 /* don't exec a shell */
128 int no_shell_flag = 0;
129
130 /*
131 * Flag indicating that nothing should be read from stdin. This can be set
132 * on the command line.
133 */
134 int stdin_null_flag = 0;
135
136 /*
137 * Flag indicating that the current process should be backgrounded and
138 * a new slave launched in the foreground for ControlPersist.
139 */
140 int need_controlpersist_detach = 0;
141
142 /* Copies of flags for ControlPersist foreground slave */
143 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
144
145 /*
146 * Flag indicating that ssh should fork after authentication. This is useful
147 * so that the passphrase can be entered manually, and then ssh goes to the
148 * background.
149 */
150 int fork_after_authentication_flag = 0;
151
152 /* forward stdio to remote host and port */
153 char *stdio_forward_host = NULL;
154 int stdio_forward_port = 0;
155
156 /*
157 * General data structure for command line options and options configurable
158 * in configuration files. See readconf.h.
159 */
160 Options options;
161
162 /* optional user configfile */
163 char *config = NULL;
164
165 /*
166 * Name of the host we are connecting to. This is the name given on the
167 * command line, or the HostName specified for the user-supplied name in a
168 * configuration file.
169 */
170 char *host;
171
172 /* socket address the host resolves to */
173 struct sockaddr_storage hostaddr;
174
175 /* Private host keys. */
176 Sensitive sensitive_data;
177
178 /* Original real UID. */
179 uid_t original_real_uid;
180 uid_t original_effective_uid;
181
182 /* command to be executed */
183 Buffer command;
184
185 /* Should we execute a command or invoke a subsystem? */
186 int subsystem_flag = 0;
187
188 /* # of replies received for global requests */
189 static int remote_forward_confirms_received = 0;
190
191 /* mux.c */
192 extern int muxserver_sock;
193 extern u_int muxclient_command;
194
195 /* Prints a help message to the user. This function never returns. */
196
197 static void
usage(void)198 usage(void)
199 {
200 fprintf(stderr,
201 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
202 " [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
203 " [-F configfile] [-I pkcs11] [-i identity_file]\n"
204 " [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n"
205 " [-O ctl_cmd] [-o option] [-p port]\n"
206 " [-Q cipher | cipher-auth | mac | kex | key]\n"
207 " [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n"
208 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
209 );
210 exit(255);
211 }
212
213 static int ssh_session(void);
214 static int ssh_session2(void);
215 static void load_public_identity_files(void);
216 static void main_sigchld_handler(int);
217
218 /* from muxclient.c */
219 void muxclient(const char *);
220 void muxserver_listen(void);
221
222 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
223 static void
tilde_expand_paths(char ** paths,u_int num_paths)224 tilde_expand_paths(char **paths, u_int num_paths)
225 {
226 u_int i;
227 char *cp;
228
229 for (i = 0; i < num_paths; i++) {
230 cp = tilde_expand_filename(paths[i], original_real_uid);
231 free(paths[i]);
232 paths[i] = cp;
233 }
234 }
235
236 /*
237 * Attempt to resolve a host name / port to a set of addresses and
238 * optionally return any CNAMEs encountered along the way.
239 * Returns NULL on failure.
240 * NB. this function must operate with a options having undefined members.
241 */
242 static struct addrinfo *
resolve_host(const char * name,int port,int logerr,char * cname,size_t clen)243 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
244 {
245 char strport[NI_MAXSERV];
246 struct addrinfo hints, *res;
247 int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
248
249 if (port <= 0)
250 port = default_ssh_port();
251
252 snprintf(strport, sizeof strport, "%u", port);
253 memset(&hints, 0, sizeof(hints));
254 hints.ai_family = options.address_family == -1 ?
255 AF_UNSPEC : options.address_family;
256 hints.ai_socktype = SOCK_STREAM;
257 if (cname != NULL)
258 hints.ai_flags = AI_CANONNAME;
259 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
260 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
261 loglevel = SYSLOG_LEVEL_ERROR;
262 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
263 __progname, name, ssh_gai_strerror(gaierr));
264 return NULL;
265 }
266 if (cname != NULL && res->ai_canonname != NULL) {
267 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
268 error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
269 __func__, name, res->ai_canonname, (u_long)clen);
270 if (clen > 0)
271 *cname = '\0';
272 }
273 }
274 return res;
275 }
276
277 /*
278 * Check whether the cname is a permitted replacement for the hostname
279 * and perform the replacement if it is.
280 * NB. this function must operate with a options having undefined members.
281 */
282 static int
check_follow_cname(char ** namep,const char * cname)283 check_follow_cname(char **namep, const char *cname)
284 {
285 int i;
286 struct allowed_cname *rule;
287
288 if (*cname == '\0' || options.num_permitted_cnames == 0 ||
289 strcmp(*namep, cname) == 0)
290 return 0;
291 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
292 return 0;
293 /*
294 * Don't attempt to canonicalize names that will be interpreted by
295 * a proxy unless the user specifically requests so.
296 */
297 if (!option_clear_or_none(options.proxy_command) &&
298 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
299 return 0;
300 debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
301 for (i = 0; i < options.num_permitted_cnames; i++) {
302 rule = options.permitted_cnames + i;
303 if (match_pattern_list(*namep, rule->source_list,
304 strlen(rule->source_list), 1) != 1 ||
305 match_pattern_list(cname, rule->target_list,
306 strlen(rule->target_list), 1) != 1)
307 continue;
308 verbose("Canonicalized DNS aliased hostname "
309 "\"%s\" => \"%s\"", *namep, cname);
310 free(*namep);
311 *namep = xstrdup(cname);
312 return 1;
313 }
314 return 0;
315 }
316
317 /*
318 * Attempt to resolve the supplied hostname after applying the user's
319 * canonicalization rules. Returns the address list for the host or NULL
320 * if no name was found after canonicalization.
321 * NB. this function must operate with a options having undefined members.
322 */
323 static struct addrinfo *
resolve_canonicalize(char ** hostp,int port)324 resolve_canonicalize(char **hostp, int port)
325 {
326 int i, ndots;
327 char *cp, *fullhost, cname_target[NI_MAXHOST];
328 struct addrinfo *addrs;
329
330 if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
331 return NULL;
332
333 /*
334 * Don't attempt to canonicalize names that will be interpreted by
335 * a proxy unless the user specifically requests so.
336 */
337 if (!option_clear_or_none(options.proxy_command) &&
338 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
339 return NULL;
340
341 /* Don't apply canonicalization to sufficiently-qualified hostnames */
342 ndots = 0;
343 for (cp = *hostp; *cp != '\0'; cp++) {
344 if (*cp == '.')
345 ndots++;
346 }
347 if (ndots > options.canonicalize_max_dots) {
348 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
349 __func__, *hostp, options.canonicalize_max_dots);
350 return NULL;
351 }
352 /* Attempt each supplied suffix */
353 for (i = 0; i < options.num_canonical_domains; i++) {
354 *cname_target = '\0';
355 xasprintf(&fullhost, "%s.%s.", *hostp,
356 options.canonical_domains[i]);
357 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
358 *hostp, fullhost);
359 if ((addrs = resolve_host(fullhost, port, 0,
360 cname_target, sizeof(cname_target))) == NULL) {
361 free(fullhost);
362 continue;
363 }
364 /* Remove trailing '.' */
365 fullhost[strlen(fullhost) - 1] = '\0';
366 /* Follow CNAME if requested */
367 if (!check_follow_cname(&fullhost, cname_target)) {
368 debug("Canonicalized hostname \"%s\" => \"%s\"",
369 *hostp, fullhost);
370 }
371 free(*hostp);
372 *hostp = fullhost;
373 return addrs;
374 }
375 if (!options.canonicalize_fallback_local)
376 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
377 debug2("%s: host %s not found in any suffix", __func__, *hostp);
378 return NULL;
379 }
380
381 /*
382 * Read per-user configuration file. Ignore the system wide config
383 * file if the user specifies a config file on the command line.
384 */
385 static void
process_config_files(struct passwd * pw)386 process_config_files(struct passwd *pw)
387 {
388 char buf[MAXPATHLEN];
389 int r;
390
391 if (config != NULL) {
392 if (strcasecmp(config, "none") != 0 &&
393 !read_config_file(config, pw, host, &options,
394 SSHCONF_USERCONF))
395 fatal("Can't open user config file %.100s: "
396 "%.100s", config, strerror(errno));
397 } else {
398 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
399 _PATH_SSH_USER_CONFFILE);
400 if (r > 0 && (size_t)r < sizeof(buf))
401 (void)read_config_file(buf, pw, host, &options,
402 SSHCONF_CHECKPERM|SSHCONF_USERCONF);
403
404 /* Read systemwide configuration file after user config. */
405 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host,
406 &options, 0);
407 }
408 }
409
410 /*
411 * Main program for the ssh client.
412 */
413 int
main(int ac,char ** av)414 main(int ac, char **av)
415 {
416 int i, r, opt, exit_status, use_syslog;
417 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile;
418 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
419 char cname[NI_MAXHOST];
420 struct stat st;
421 struct passwd *pw;
422 int timeout_ms;
423 extern int optind, optreset;
424 extern char *optarg;
425 Forward fwd;
426 struct addrinfo *addrs = NULL;
427
428 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
429 sanitise_stdfd();
430
431 __progname = ssh_get_progname(av[0]);
432
433 #ifndef HAVE_SETPROCTITLE
434 /* Prepare for later setproctitle emulation */
435 /* Save argv so it isn't clobbered by setproctitle() emulation */
436 saved_av = xcalloc(ac + 1, sizeof(*saved_av));
437 for (i = 0; i < ac; i++)
438 saved_av[i] = xstrdup(av[i]);
439 saved_av[i] = NULL;
440 compat_init_setproctitle(ac, av);
441 av = saved_av;
442 #endif
443
444 /*
445 * Discard other fds that are hanging around. These can cause problem
446 * with backgrounded ssh processes started by ControlPersist.
447 */
448 closefrom(STDERR_FILENO + 1);
449
450 /*
451 * Save the original real uid. It will be needed later (uid-swapping
452 * may clobber the real uid).
453 */
454 original_real_uid = getuid();
455 original_effective_uid = geteuid();
456
457 /*
458 * Use uid-swapping to give up root privileges for the duration of
459 * option processing. We will re-instantiate the rights when we are
460 * ready to create the privileged port, and will permanently drop
461 * them when the port has been created (actually, when the connection
462 * has been made, as we may need to create the port several times).
463 */
464 PRIV_END;
465
466 #ifdef HAVE_SETRLIMIT
467 /* If we are installed setuid root be careful to not drop core. */
468 if (original_real_uid != original_effective_uid) {
469 struct rlimit rlim;
470 rlim.rlim_cur = rlim.rlim_max = 0;
471 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
472 fatal("setrlimit failed: %.100s", strerror(errno));
473 }
474 #endif
475 /* Get user data. */
476 pw = getpwuid(original_real_uid);
477 if (!pw) {
478 logit("No user exists for uid %lu", (u_long)original_real_uid);
479 exit(255);
480 }
481 /* Take a copy of the returned structure. */
482 pw = pwcopy(pw);
483
484 /*
485 * Set our umask to something reasonable, as some files are created
486 * with the default umask. This will make them world-readable but
487 * writable only by the owner, which is ok for all files for which we
488 * don't set the modes explicitly.
489 */
490 umask(022);
491
492 /*
493 * Initialize option structure to indicate that no values have been
494 * set.
495 */
496 initialize_options(&options);
497
498 /* Parse command-line arguments. */
499 host = NULL;
500 use_syslog = 0;
501 logfile = NULL;
502 argv0 = av[0];
503
504 again:
505 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
506 "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
507 switch (opt) {
508 case '1':
509 options.protocol = SSH_PROTO_1;
510 break;
511 case '2':
512 options.protocol = SSH_PROTO_2;
513 break;
514 case '4':
515 options.address_family = AF_INET;
516 break;
517 case '6':
518 options.address_family = AF_INET6;
519 break;
520 case 'n':
521 stdin_null_flag = 1;
522 break;
523 case 'f':
524 fork_after_authentication_flag = 1;
525 stdin_null_flag = 1;
526 break;
527 case 'x':
528 options.forward_x11 = 0;
529 break;
530 case 'X':
531 options.forward_x11 = 1;
532 break;
533 case 'y':
534 use_syslog = 1;
535 break;
536 case 'E':
537 logfile = xstrdup(optarg);
538 break;
539 case 'Y':
540 options.forward_x11 = 1;
541 options.forward_x11_trusted = 1;
542 break;
543 case 'g':
544 options.gateway_ports = 1;
545 break;
546 case 'O':
547 if (stdio_forward_host != NULL)
548 fatal("Cannot specify multiplexing "
549 "command with -W");
550 else if (muxclient_command != 0)
551 fatal("Multiplexing command already specified");
552 if (strcmp(optarg, "check") == 0)
553 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
554 else if (strcmp(optarg, "forward") == 0)
555 muxclient_command = SSHMUX_COMMAND_FORWARD;
556 else if (strcmp(optarg, "exit") == 0)
557 muxclient_command = SSHMUX_COMMAND_TERMINATE;
558 else if (strcmp(optarg, "stop") == 0)
559 muxclient_command = SSHMUX_COMMAND_STOP;
560 else if (strcmp(optarg, "cancel") == 0)
561 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
562 else
563 fatal("Invalid multiplex command.");
564 break;
565 case 'P': /* deprecated */
566 options.use_privileged_port = 0;
567 break;
568 case 'Q':
569 cp = NULL;
570 if (strcmp(optarg, "cipher") == 0)
571 cp = cipher_alg_list('\n', 0);
572 else if (strcmp(optarg, "cipher-auth") == 0)
573 cp = cipher_alg_list('\n', 1);
574 else if (strcmp(optarg, "mac") == 0)
575 cp = mac_alg_list('\n');
576 else if (strcmp(optarg, "kex") == 0)
577 cp = kex_alg_list('\n');
578 else if (strcmp(optarg, "key") == 0)
579 cp = key_alg_list(0, 0);
580 else if (strcmp(optarg, "key-cert") == 0)
581 cp = key_alg_list(1, 0);
582 else if (strcmp(optarg, "key-plain") == 0)
583 cp = key_alg_list(0, 1);
584 if (cp == NULL)
585 fatal("Unsupported query \"%s\"", optarg);
586 printf("%s\n", cp);
587 free(cp);
588 exit(0);
589 break;
590 case 'a':
591 options.forward_agent = 0;
592 break;
593 case 'A':
594 options.forward_agent = 1;
595 break;
596 case 'k':
597 options.gss_deleg_creds = 0;
598 break;
599 case 'K':
600 options.gss_authentication = 1;
601 options.gss_deleg_creds = 1;
602 break;
603 case 'i':
604 if (stat(optarg, &st) < 0) {
605 fprintf(stderr, "Warning: Identity file %s "
606 "not accessible: %s.\n", optarg,
607 strerror(errno));
608 break;
609 }
610 add_identity_file(&options, NULL, optarg, 1);
611 break;
612 case 'I':
613 #ifdef ENABLE_PKCS11
614 options.pkcs11_provider = xstrdup(optarg);
615 #else
616 fprintf(stderr, "no support for PKCS#11.\n");
617 #endif
618 break;
619 case 't':
620 if (options.request_tty == REQUEST_TTY_YES)
621 options.request_tty = REQUEST_TTY_FORCE;
622 else
623 options.request_tty = REQUEST_TTY_YES;
624 break;
625 case 'v':
626 if (debug_flag == 0) {
627 debug_flag = 1;
628 options.log_level = SYSLOG_LEVEL_DEBUG1;
629 } else {
630 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
631 options.log_level++;
632 }
633 break;
634 case 'V':
635 if (options.version_addendum &&
636 *options.version_addendum != '\0')
637 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
638 options.hpn_disabled ? "" : SSH_VERSION_HPN,
639 options.version_addendum,
640 SSLeay_version(SSLEAY_VERSION));
641 else
642 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE,
643 options.hpn_disabled ? "" : SSH_VERSION_HPN,
644 SSLeay_version(SSLEAY_VERSION));
645 if (opt == 'V')
646 exit(0);
647 break;
648 case 'w':
649 if (options.tun_open == -1)
650 options.tun_open = SSH_TUNMODE_DEFAULT;
651 options.tun_local = a2tun(optarg, &options.tun_remote);
652 if (options.tun_local == SSH_TUNID_ERR) {
653 fprintf(stderr,
654 "Bad tun device '%s'\n", optarg);
655 exit(255);
656 }
657 break;
658 case 'W':
659 if (stdio_forward_host != NULL)
660 fatal("stdio forward already specified");
661 if (muxclient_command != 0)
662 fatal("Cannot specify stdio forward with -O");
663 if (parse_forward(&fwd, optarg, 1, 0)) {
664 stdio_forward_host = fwd.listen_host;
665 stdio_forward_port = fwd.listen_port;
666 free(fwd.connect_host);
667 } else {
668 fprintf(stderr,
669 "Bad stdio forwarding specification '%s'\n",
670 optarg);
671 exit(255);
672 }
673 options.request_tty = REQUEST_TTY_NO;
674 no_shell_flag = 1;
675 options.clear_forwardings = 1;
676 options.exit_on_forward_failure = 1;
677 break;
678 case 'q':
679 options.log_level = SYSLOG_LEVEL_QUIET;
680 break;
681 case 'e':
682 if (optarg[0] == '^' && optarg[2] == 0 &&
683 (u_char) optarg[1] >= 64 &&
684 (u_char) optarg[1] < 128)
685 options.escape_char = (u_char) optarg[1] & 31;
686 else if (strlen(optarg) == 1)
687 options.escape_char = (u_char) optarg[0];
688 else if (strcmp(optarg, "none") == 0)
689 options.escape_char = SSH_ESCAPECHAR_NONE;
690 else {
691 fprintf(stderr, "Bad escape character '%s'.\n",
692 optarg);
693 exit(255);
694 }
695 break;
696 case 'c':
697 if (ciphers_valid(optarg)) {
698 /* SSH2 only */
699 options.ciphers = xstrdup(optarg);
700 options.cipher = SSH_CIPHER_INVALID;
701 } else {
702 /* SSH1 only */
703 options.cipher = cipher_number(optarg);
704 if (options.cipher == -1) {
705 fprintf(stderr,
706 "Unknown cipher type '%s'\n",
707 optarg);
708 exit(255);
709 }
710 if (options.cipher == SSH_CIPHER_3DES)
711 options.ciphers = "3des-cbc";
712 else if (options.cipher == SSH_CIPHER_BLOWFISH)
713 options.ciphers = "blowfish-cbc";
714 else
715 options.ciphers = (char *)-1;
716 }
717 break;
718 case 'm':
719 if (mac_valid(optarg))
720 options.macs = xstrdup(optarg);
721 else {
722 fprintf(stderr, "Unknown mac type '%s'\n",
723 optarg);
724 exit(255);
725 }
726 break;
727 case 'M':
728 if (options.control_master == SSHCTL_MASTER_YES)
729 options.control_master = SSHCTL_MASTER_ASK;
730 else
731 options.control_master = SSHCTL_MASTER_YES;
732 break;
733 case 'p':
734 options.port = a2port(optarg);
735 if (options.port <= 0) {
736 fprintf(stderr, "Bad port '%s'\n", optarg);
737 exit(255);
738 }
739 break;
740 case 'l':
741 options.user = optarg;
742 break;
743
744 case 'L':
745 if (parse_forward(&fwd, optarg, 0, 0))
746 add_local_forward(&options, &fwd);
747 else {
748 fprintf(stderr,
749 "Bad local forwarding specification '%s'\n",
750 optarg);
751 exit(255);
752 }
753 break;
754
755 case 'R':
756 if (parse_forward(&fwd, optarg, 0, 1)) {
757 add_remote_forward(&options, &fwd);
758 } else {
759 fprintf(stderr,
760 "Bad remote forwarding specification "
761 "'%s'\n", optarg);
762 exit(255);
763 }
764 break;
765
766 case 'D':
767 if (parse_forward(&fwd, optarg, 1, 0)) {
768 add_local_forward(&options, &fwd);
769 } else {
770 fprintf(stderr,
771 "Bad dynamic forwarding specification "
772 "'%s'\n", optarg);
773 exit(255);
774 }
775 break;
776
777 case 'C':
778 options.compression = 1;
779 break;
780 case 'N':
781 no_shell_flag = 1;
782 options.request_tty = REQUEST_TTY_NO;
783 break;
784 case 'T':
785 options.request_tty = REQUEST_TTY_NO;
786 #ifdef NONE_CIPHER_ENABLED
787 /*
788 * Ensure that the user does not try to backdoor a
789 * NONE cipher switch on an interactive session by
790 * explicitly disabling it if the user asks for a
791 * session without a tty.
792 */
793 options.none_switch = 0;
794 #endif
795 break;
796 case 'o':
797 line = xstrdup(optarg);
798 if (process_config_line(&options, pw, host ? host : "",
799 line, "command-line", 0, NULL, SSHCONF_USERCONF)
800 != 0)
801 exit(255);
802 free(line);
803 break;
804 case 's':
805 subsystem_flag = 1;
806 break;
807 case 'S':
808 if (options.control_path != NULL)
809 free(options.control_path);
810 options.control_path = xstrdup(optarg);
811 break;
812 case 'b':
813 options.bind_address = optarg;
814 break;
815 case 'F':
816 config = optarg;
817 break;
818 default:
819 usage();
820 }
821 }
822
823 ac -= optind;
824 av += optind;
825
826 if (ac > 0 && !host) {
827 if (strrchr(*av, '@')) {
828 p = xstrdup(*av);
829 cp = strrchr(p, '@');
830 if (cp == NULL || cp == p)
831 usage();
832 options.user = p;
833 *cp = '\0';
834 host = xstrdup(++cp);
835 } else
836 host = xstrdup(*av);
837 if (ac > 1) {
838 optind = optreset = 1;
839 goto again;
840 }
841 ac--, av++;
842 }
843
844 /* Check that we got a host name. */
845 if (!host)
846 usage();
847
848 host_arg = xstrdup(host);
849
850 OpenSSL_add_all_algorithms();
851 ERR_load_crypto_strings();
852
853 /* Initialize the command to execute on remote host. */
854 buffer_init(&command);
855
856 /*
857 * Save the command to execute on the remote host in a buffer. There
858 * is no limit on the length of the command, except by the maximum
859 * packet size. Also sets the tty flag if there is no command.
860 */
861 if (!ac) {
862 /* No command specified - execute shell on a tty. */
863 if (subsystem_flag) {
864 fprintf(stderr,
865 "You must specify a subsystem to invoke.\n");
866 usage();
867 }
868 } else {
869 /* A command has been specified. Store it into the buffer. */
870 for (i = 0; i < ac; i++) {
871 if (i)
872 buffer_append(&command, " ", 1);
873 buffer_append(&command, av[i], strlen(av[i]));
874 }
875 }
876
877 /* Cannot fork to background if no command. */
878 if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
879 !no_shell_flag)
880 fatal("Cannot fork into background without a command "
881 "to execute.");
882
883 /*
884 * Initialize "log" output. Since we are the client all output
885 * goes to stderr unless otherwise specified by -y or -E.
886 */
887 if (use_syslog && logfile != NULL)
888 fatal("Can't specify both -y and -E");
889 if (logfile != NULL) {
890 log_redirect_stderr_to(logfile);
891 free(logfile);
892 }
893 log_init(argv0,
894 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
895 SYSLOG_FACILITY_USER, !use_syslog);
896
897 if (debug_flag)
898 logit("%s, %s", SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
899
900 /* Parse the configuration files */
901 process_config_files(pw);
902
903 /* Hostname canonicalisation needs a few options filled. */
904 fill_default_options_for_canonicalization(&options);
905
906 /* If the user has replaced the hostname then take it into use now */
907 if (options.hostname != NULL) {
908 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
909 cp = percent_expand(options.hostname,
910 "h", host, (char *)NULL);
911 free(host);
912 host = cp;
913 }
914
915 /* If canonicalization requested then try to apply it */
916 lowercase(host);
917 if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
918 addrs = resolve_canonicalize(&host, options.port);
919
920 /*
921 * If CanonicalizePermittedCNAMEs have been specified but
922 * other canonicalization did not happen (by not being requested
923 * or by failing with fallback) then the hostname may still be changed
924 * as a result of CNAME following.
925 *
926 * Try to resolve the bare hostname name using the system resolver's
927 * usual search rules and then apply the CNAME follow rules.
928 *
929 * Skip the lookup if a ProxyCommand is being used unless the user
930 * has specifically requested canonicalisation for this case via
931 * CanonicalizeHostname=always
932 */
933 if (addrs == NULL && options.num_permitted_cnames != 0 &&
934 (option_clear_or_none(options.proxy_command) ||
935 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
936 if ((addrs = resolve_host(host, options.port, 1,
937 cname, sizeof(cname))) == NULL)
938 cleanup_exit(255); /* resolve_host logs the error */
939 check_follow_cname(&host, cname);
940 }
941
942 /*
943 * If the target hostname has changed as a result of canonicalisation
944 * then re-parse the configuration files as new stanzas may match.
945 */
946 if (strcasecmp(host_arg, host) != 0) {
947 debug("Hostname has changed; re-reading configuration");
948 process_config_files(pw);
949 }
950
951 /* Fill configuration defaults. */
952 fill_default_options(&options);
953
954 if (options.port == 0)
955 options.port = default_ssh_port();
956 channel_set_af(options.address_family);
957
958 /* Tidy and check options */
959 if (options.host_key_alias != NULL)
960 lowercase(options.host_key_alias);
961 if (options.proxy_command != NULL &&
962 strcmp(options.proxy_command, "-") == 0 &&
963 options.proxy_use_fdpass)
964 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
965 #ifndef HAVE_CYGWIN
966 if (original_effective_uid != 0)
967 options.use_privileged_port = 0;
968 #endif
969
970 /* reinit */
971 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
972
973 if (options.request_tty == REQUEST_TTY_YES ||
974 options.request_tty == REQUEST_TTY_FORCE)
975 tty_flag = 1;
976
977 /* Allocate a tty by default if no command specified. */
978 if (buffer_len(&command) == 0)
979 tty_flag = options.request_tty != REQUEST_TTY_NO;
980
981 /* Force no tty */
982 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
983 tty_flag = 0;
984 /* Do not allocate a tty if stdin is not a tty. */
985 if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
986 options.request_tty != REQUEST_TTY_FORCE) {
987 if (tty_flag)
988 logit("Pseudo-terminal will not be allocated because "
989 "stdin is not a terminal.");
990 tty_flag = 0;
991 }
992
993 seed_rng();
994
995 if (options.user == NULL)
996 options.user = xstrdup(pw->pw_name);
997
998 if (gethostname(thishost, sizeof(thishost)) == -1)
999 fatal("gethostname: %s", strerror(errno));
1000 strlcpy(shorthost, thishost, sizeof(shorthost));
1001 shorthost[strcspn(thishost, ".")] = '\0';
1002 snprintf(portstr, sizeof(portstr), "%d", options.port);
1003
1004 if (options.local_command != NULL) {
1005 debug3("expanding LocalCommand: %s", options.local_command);
1006 cp = options.local_command;
1007 options.local_command = percent_expand(cp, "d", pw->pw_dir,
1008 "h", host, "l", thishost, "n", host_arg, "r", options.user,
1009 "p", portstr, "u", pw->pw_name, "L", shorthost,
1010 (char *)NULL);
1011 debug3("expanded LocalCommand: %s", options.local_command);
1012 free(cp);
1013 }
1014
1015 if (options.control_path != NULL) {
1016 cp = tilde_expand_filename(options.control_path,
1017 original_real_uid);
1018 free(options.control_path);
1019 options.control_path = percent_expand(cp, "h", host,
1020 "l", thishost, "n", host_arg, "r", options.user,
1021 "p", portstr, "u", pw->pw_name, "L", shorthost,
1022 (char *)NULL);
1023 free(cp);
1024 }
1025 if (muxclient_command != 0 && options.control_path == NULL)
1026 fatal("No ControlPath specified for \"-O\" command");
1027 if (options.control_path != NULL)
1028 muxclient(options.control_path);
1029
1030 /*
1031 * If hostname canonicalisation was not enabled, then we may not
1032 * have yet resolved the hostname. Do so now.
1033 */
1034 if (addrs == NULL && options.proxy_command == NULL) {
1035 if ((addrs = resolve_host(host, options.port, 1,
1036 cname, sizeof(cname))) == NULL)
1037 cleanup_exit(255); /* resolve_host logs the error */
1038 }
1039
1040 timeout_ms = options.connection_timeout * 1000;
1041
1042 /* Open a connection to the remote host. */
1043 if (ssh_connect(host, addrs, &hostaddr, options.port,
1044 options.address_family, options.connection_attempts,
1045 &timeout_ms, options.tcp_keep_alive,
1046 options.use_privileged_port) != 0)
1047 exit(255);
1048
1049 if (addrs != NULL)
1050 freeaddrinfo(addrs);
1051
1052 packet_set_timeout(options.server_alive_interval,
1053 options.server_alive_count_max);
1054
1055 if (timeout_ms > 0)
1056 debug3("timeout: %d ms remain after connect", timeout_ms);
1057
1058 /*
1059 * If we successfully made the connection, load the host private key
1060 * in case we will need it later for combined rsa-rhosts
1061 * authentication. This must be done before releasing extra
1062 * privileges, because the file is only readable by root.
1063 * If we cannot access the private keys, load the public keys
1064 * instead and try to execute the ssh-keysign helper instead.
1065 */
1066 sensitive_data.nkeys = 0;
1067 sensitive_data.keys = NULL;
1068 sensitive_data.external_keysign = 0;
1069 if (options.rhosts_rsa_authentication ||
1070 options.hostbased_authentication) {
1071 sensitive_data.nkeys = 9;
1072 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1073 sizeof(Key));
1074 for (i = 0; i < sensitive_data.nkeys; i++)
1075 sensitive_data.keys[i] = NULL;
1076
1077 PRIV_START;
1078 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1079 _PATH_HOST_KEY_FILE, "", NULL, NULL);
1080 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
1081 _PATH_HOST_DSA_KEY_FILE, "", NULL);
1082 #ifdef OPENSSL_HAS_ECC
1083 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
1084 _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1085 #endif
1086 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1087 _PATH_HOST_RSA_KEY_FILE, "", NULL);
1088 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519,
1089 _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1090 sensitive_data.keys[5] = key_load_private_type(KEY_DSA,
1091 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1092 #ifdef OPENSSL_HAS_ECC
1093 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA,
1094 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1095 #endif
1096 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1097 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1098 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519,
1099 _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1100 PRIV_END;
1101
1102 if (options.hostbased_authentication == 1 &&
1103 sensitive_data.keys[0] == NULL &&
1104 sensitive_data.keys[5] == NULL &&
1105 sensitive_data.keys[6] == NULL &&
1106 sensitive_data.keys[7] == NULL &&
1107 sensitive_data.keys[8] == NULL) {
1108 sensitive_data.keys[1] = key_load_cert(
1109 _PATH_HOST_DSA_KEY_FILE);
1110 #ifdef OPENSSL_HAS_ECC
1111 sensitive_data.keys[2] = key_load_cert(
1112 _PATH_HOST_ECDSA_KEY_FILE);
1113 #endif
1114 sensitive_data.keys[3] = key_load_cert(
1115 _PATH_HOST_RSA_KEY_FILE);
1116 sensitive_data.keys[4] = key_load_cert(
1117 _PATH_HOST_ED25519_KEY_FILE);
1118 sensitive_data.keys[5] = key_load_public(
1119 _PATH_HOST_DSA_KEY_FILE, NULL);
1120 #ifdef OPENSSL_HAS_ECC
1121 sensitive_data.keys[6] = key_load_public(
1122 _PATH_HOST_ECDSA_KEY_FILE, NULL);
1123 #endif
1124 sensitive_data.keys[7] = key_load_public(
1125 _PATH_HOST_RSA_KEY_FILE, NULL);
1126 sensitive_data.keys[8] = key_load_public(
1127 _PATH_HOST_ED25519_KEY_FILE, NULL);
1128 sensitive_data.external_keysign = 1;
1129 }
1130 }
1131 /*
1132 * Get rid of any extra privileges that we may have. We will no
1133 * longer need them. Also, extra privileges could make it very hard
1134 * to read identity files and other non-world-readable files from the
1135 * user's home directory if it happens to be on a NFS volume where
1136 * root is mapped to nobody.
1137 */
1138 if (original_effective_uid == 0) {
1139 PRIV_START;
1140 permanently_set_uid(pw);
1141 }
1142
1143 /*
1144 * Now that we are back to our own permissions, create ~/.ssh
1145 * directory if it doesn't already exist.
1146 */
1147 if (config == NULL) {
1148 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1149 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1150 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1151 #ifdef WITH_SELINUX
1152 ssh_selinux_setfscreatecon(buf);
1153 #endif
1154 if (mkdir(buf, 0700) < 0)
1155 error("Could not create directory '%.200s'.",
1156 buf);
1157 #ifdef WITH_SELINUX
1158 ssh_selinux_setfscreatecon(NULL);
1159 #endif
1160 }
1161 }
1162 /* load options.identity_files */
1163 load_public_identity_files();
1164
1165 /* Expand ~ in known host file names. */
1166 tilde_expand_paths(options.system_hostfiles,
1167 options.num_system_hostfiles);
1168 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1169
1170 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1171 signal(SIGCHLD, main_sigchld_handler);
1172
1173 /* Log into the remote system. Never returns if the login fails. */
1174 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1175 options.port, pw, timeout_ms);
1176
1177 if (packet_connection_is_on_socket()) {
1178 verbose("Authenticated to %s ([%s]:%d).", host,
1179 get_remote_ipaddr(), get_remote_port());
1180 } else {
1181 verbose("Authenticated to %s (via proxy).", host);
1182 }
1183
1184 /* We no longer need the private host keys. Clear them now. */
1185 if (sensitive_data.nkeys != 0) {
1186 for (i = 0; i < sensitive_data.nkeys; i++) {
1187 if (sensitive_data.keys[i] != NULL) {
1188 /* Destroys contents safely */
1189 debug3("clear hostkey %d", i);
1190 key_free(sensitive_data.keys[i]);
1191 sensitive_data.keys[i] = NULL;
1192 }
1193 }
1194 free(sensitive_data.keys);
1195 }
1196 for (i = 0; i < options.num_identity_files; i++) {
1197 free(options.identity_files[i]);
1198 options.identity_files[i] = NULL;
1199 if (options.identity_keys[i]) {
1200 key_free(options.identity_keys[i]);
1201 options.identity_keys[i] = NULL;
1202 }
1203 }
1204
1205 exit_status = compat20 ? ssh_session2() : ssh_session();
1206 packet_close();
1207
1208 if (options.control_path != NULL && muxserver_sock != -1)
1209 unlink(options.control_path);
1210
1211 /* Kill ProxyCommand if it is running. */
1212 ssh_kill_proxy_command();
1213
1214 return exit_status;
1215 }
1216
1217 static void
control_persist_detach(void)1218 control_persist_detach(void)
1219 {
1220 pid_t pid;
1221 int devnull;
1222
1223 debug("%s: backgrounding master process", __func__);
1224
1225 /*
1226 * master (current process) into the background, and make the
1227 * foreground process a client of the backgrounded master.
1228 */
1229 switch ((pid = fork())) {
1230 case -1:
1231 fatal("%s: fork: %s", __func__, strerror(errno));
1232 case 0:
1233 /* Child: master process continues mainloop */
1234 break;
1235 default:
1236 /* Parent: set up mux slave to connect to backgrounded master */
1237 debug2("%s: background process is %ld", __func__, (long)pid);
1238 stdin_null_flag = ostdin_null_flag;
1239 options.request_tty = orequest_tty;
1240 tty_flag = otty_flag;
1241 close(muxserver_sock);
1242 muxserver_sock = -1;
1243 options.control_master = SSHCTL_MASTER_NO;
1244 muxclient(options.control_path);
1245 /* muxclient() doesn't return on success. */
1246 fatal("Failed to connect to new control master");
1247 }
1248 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1249 error("%s: open(\"/dev/null\"): %s", __func__,
1250 strerror(errno));
1251 } else {
1252 if (dup2(devnull, STDIN_FILENO) == -1 ||
1253 dup2(devnull, STDOUT_FILENO) == -1)
1254 error("%s: dup2: %s", __func__, strerror(errno));
1255 if (devnull > STDERR_FILENO)
1256 close(devnull);
1257 }
1258 daemon(1, 1);
1259 setproctitle("%s [mux]", options.control_path);
1260 }
1261
1262 /* Do fork() after authentication. Used by "ssh -f" */
1263 static void
fork_postauth(void)1264 fork_postauth(void)
1265 {
1266 if (need_controlpersist_detach)
1267 control_persist_detach();
1268 debug("forking to background");
1269 fork_after_authentication_flag = 0;
1270 if (daemon(1, 1) < 0)
1271 fatal("daemon() failed: %.200s", strerror(errno));
1272 }
1273
1274 /* Callback for remote forward global requests */
1275 static void
ssh_confirm_remote_forward(int type,u_int32_t seq,void * ctxt)1276 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1277 {
1278 Forward *rfwd = (Forward *)ctxt;
1279
1280 /* XXX verbose() on failure? */
1281 debug("remote forward %s for: listen %d, connect %s:%d",
1282 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1283 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
1284 if (rfwd->listen_port == 0) {
1285 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1286 rfwd->allocated_port = packet_get_int();
1287 logit("Allocated port %u for remote forward to %s:%d",
1288 rfwd->allocated_port,
1289 rfwd->connect_host, rfwd->connect_port);
1290 channel_update_permitted_opens(rfwd->handle,
1291 rfwd->allocated_port);
1292 } else {
1293 channel_update_permitted_opens(rfwd->handle, -1);
1294 }
1295 }
1296
1297 if (type == SSH2_MSG_REQUEST_FAILURE) {
1298 if (options.exit_on_forward_failure)
1299 fatal("Error: remote port forwarding failed for "
1300 "listen port %d", rfwd->listen_port);
1301 else
1302 logit("Warning: remote port forwarding failed for "
1303 "listen port %d", rfwd->listen_port);
1304 }
1305 if (++remote_forward_confirms_received == options.num_remote_forwards) {
1306 debug("All remote forwarding requests processed");
1307 if (fork_after_authentication_flag)
1308 fork_postauth();
1309 }
1310 }
1311
1312 static void
client_cleanup_stdio_fwd(int id,void * arg)1313 client_cleanup_stdio_fwd(int id, void *arg)
1314 {
1315 debug("stdio forwarding: done");
1316 cleanup_exit(0);
1317 }
1318
1319 static void
ssh_init_stdio_forwarding(void)1320 ssh_init_stdio_forwarding(void)
1321 {
1322 Channel *c;
1323 int in, out;
1324
1325 if (stdio_forward_host == NULL)
1326 return;
1327 if (!compat20)
1328 fatal("stdio forwarding require Protocol 2");
1329
1330 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1331
1332 if ((in = dup(STDIN_FILENO)) < 0 ||
1333 (out = dup(STDOUT_FILENO)) < 0)
1334 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1335 if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1336 stdio_forward_port, in, out)) == NULL)
1337 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1338 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1339 }
1340
1341 static void
ssh_init_forwarding(void)1342 ssh_init_forwarding(void)
1343 {
1344 int success = 0;
1345 int i;
1346
1347 /* Initiate local TCP/IP port forwardings. */
1348 for (i = 0; i < options.num_local_forwards; i++) {
1349 debug("Local connections to %.200s:%d forwarded to remote "
1350 "address %.200s:%d",
1351 (options.local_forwards[i].listen_host == NULL) ?
1352 (options.gateway_ports ? "*" : "LOCALHOST") :
1353 options.local_forwards[i].listen_host,
1354 options.local_forwards[i].listen_port,
1355 options.local_forwards[i].connect_host,
1356 options.local_forwards[i].connect_port);
1357 success += channel_setup_local_fwd_listener(
1358 options.local_forwards[i].listen_host,
1359 options.local_forwards[i].listen_port,
1360 options.local_forwards[i].connect_host,
1361 options.local_forwards[i].connect_port,
1362 options.gateway_ports);
1363 }
1364 if (i > 0 && success != i && options.exit_on_forward_failure)
1365 fatal("Could not request local forwarding.");
1366 if (i > 0 && success == 0)
1367 error("Could not request local forwarding.");
1368
1369 /* Initiate remote TCP/IP port forwardings. */
1370 for (i = 0; i < options.num_remote_forwards; i++) {
1371 debug("Remote connections from %.200s:%d forwarded to "
1372 "local address %.200s:%d",
1373 (options.remote_forwards[i].listen_host == NULL) ?
1374 "LOCALHOST" : options.remote_forwards[i].listen_host,
1375 options.remote_forwards[i].listen_port,
1376 options.remote_forwards[i].connect_host,
1377 options.remote_forwards[i].connect_port);
1378 options.remote_forwards[i].handle =
1379 channel_request_remote_forwarding(
1380 options.remote_forwards[i].listen_host,
1381 options.remote_forwards[i].listen_port,
1382 options.remote_forwards[i].connect_host,
1383 options.remote_forwards[i].connect_port);
1384 if (options.remote_forwards[i].handle < 0) {
1385 if (options.exit_on_forward_failure)
1386 fatal("Could not request remote forwarding.");
1387 else
1388 logit("Warning: Could not request remote "
1389 "forwarding.");
1390 } else {
1391 client_register_global_confirm(ssh_confirm_remote_forward,
1392 &options.remote_forwards[i]);
1393 }
1394 }
1395
1396 /* Initiate tunnel forwarding. */
1397 if (options.tun_open != SSH_TUNMODE_NO) {
1398 if (client_request_tun_fwd(options.tun_open,
1399 options.tun_local, options.tun_remote) == -1) {
1400 if (options.exit_on_forward_failure)
1401 fatal("Could not request tunnel forwarding.");
1402 else
1403 error("Could not request tunnel forwarding.");
1404 }
1405 }
1406 }
1407
1408 static void
check_agent_present(void)1409 check_agent_present(void)
1410 {
1411 if (options.forward_agent) {
1412 /* Clear agent forwarding if we don't have an agent. */
1413 if (!ssh_agent_present())
1414 options.forward_agent = 0;
1415 }
1416 }
1417
1418 static int
ssh_session(void)1419 ssh_session(void)
1420 {
1421 int type;
1422 int interactive = 0;
1423 int have_tty = 0;
1424 struct winsize ws;
1425 char *cp;
1426 const char *display;
1427
1428 /* Enable compression if requested. */
1429 if (options.compression) {
1430 debug("Requesting compression at level %d.",
1431 options.compression_level);
1432
1433 if (options.compression_level < 1 ||
1434 options.compression_level > 9)
1435 fatal("Compression level must be from 1 (fast) to "
1436 "9 (slow, best).");
1437
1438 /* Send the request. */
1439 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1440 packet_put_int(options.compression_level);
1441 packet_send();
1442 packet_write_wait();
1443 type = packet_read();
1444 if (type == SSH_SMSG_SUCCESS)
1445 packet_start_compression(options.compression_level);
1446 else if (type == SSH_SMSG_FAILURE)
1447 logit("Warning: Remote host refused compression.");
1448 else
1449 packet_disconnect("Protocol error waiting for "
1450 "compression response.");
1451 }
1452 /* Allocate a pseudo tty if appropriate. */
1453 if (tty_flag) {
1454 debug("Requesting pty.");
1455
1456 /* Start the packet. */
1457 packet_start(SSH_CMSG_REQUEST_PTY);
1458
1459 /* Store TERM in the packet. There is no limit on the
1460 length of the string. */
1461 cp = getenv("TERM");
1462 if (!cp)
1463 cp = "";
1464 packet_put_cstring(cp);
1465
1466 /* Store window size in the packet. */
1467 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1468 memset(&ws, 0, sizeof(ws));
1469 packet_put_int((u_int)ws.ws_row);
1470 packet_put_int((u_int)ws.ws_col);
1471 packet_put_int((u_int)ws.ws_xpixel);
1472 packet_put_int((u_int)ws.ws_ypixel);
1473
1474 /* Store tty modes in the packet. */
1475 tty_make_modes(fileno(stdin), NULL);
1476
1477 /* Send the packet, and wait for it to leave. */
1478 packet_send();
1479 packet_write_wait();
1480
1481 /* Read response from the server. */
1482 type = packet_read();
1483 if (type == SSH_SMSG_SUCCESS) {
1484 interactive = 1;
1485 have_tty = 1;
1486 } else if (type == SSH_SMSG_FAILURE)
1487 logit("Warning: Remote host failed or refused to "
1488 "allocate a pseudo tty.");
1489 else
1490 packet_disconnect("Protocol error waiting for pty "
1491 "request response.");
1492 }
1493 /* Request X11 forwarding if enabled and DISPLAY is set. */
1494 display = getenv("DISPLAY");
1495 if (options.forward_x11 && display != NULL) {
1496 char *proto, *data;
1497 /* Get reasonable local authentication information. */
1498 client_x11_get_proto(display, options.xauth_location,
1499 options.forward_x11_trusted,
1500 options.forward_x11_timeout,
1501 &proto, &data);
1502 /* Request forwarding with authentication spoofing. */
1503 debug("Requesting X11 forwarding with authentication "
1504 "spoofing.");
1505 x11_request_forwarding_with_spoofing(0, display, proto,
1506 data, 0);
1507 /* Read response from the server. */
1508 type = packet_read();
1509 if (type == SSH_SMSG_SUCCESS) {
1510 interactive = 1;
1511 } else if (type == SSH_SMSG_FAILURE) {
1512 logit("Warning: Remote host denied X11 forwarding.");
1513 } else {
1514 packet_disconnect("Protocol error waiting for X11 "
1515 "forwarding");
1516 }
1517 }
1518 /* Tell the packet module whether this is an interactive session. */
1519 packet_set_interactive(interactive,
1520 options.ip_qos_interactive, options.ip_qos_bulk);
1521
1522 /* Request authentication agent forwarding if appropriate. */
1523 check_agent_present();
1524
1525 if (options.forward_agent) {
1526 debug("Requesting authentication agent forwarding.");
1527 auth_request_forwarding();
1528
1529 /* Read response from the server. */
1530 type = packet_read();
1531 packet_check_eom();
1532 if (type != SSH_SMSG_SUCCESS)
1533 logit("Warning: Remote host denied authentication agent forwarding.");
1534 }
1535
1536 /* Initiate port forwardings. */
1537 ssh_init_stdio_forwarding();
1538 ssh_init_forwarding();
1539
1540 /* Execute a local command */
1541 if (options.local_command != NULL &&
1542 options.permit_local_command)
1543 ssh_local_cmd(options.local_command);
1544
1545 /*
1546 * If requested and we are not interested in replies to remote
1547 * forwarding requests, then let ssh continue in the background.
1548 */
1549 if (fork_after_authentication_flag) {
1550 if (options.exit_on_forward_failure &&
1551 options.num_remote_forwards > 0) {
1552 debug("deferring postauth fork until remote forward "
1553 "confirmation received");
1554 } else
1555 fork_postauth();
1556 }
1557
1558 /*
1559 * If a command was specified on the command line, execute the
1560 * command now. Otherwise request the server to start a shell.
1561 */
1562 if (buffer_len(&command) > 0) {
1563 int len = buffer_len(&command);
1564 if (len > 900)
1565 len = 900;
1566 debug("Sending command: %.*s", len,
1567 (u_char *)buffer_ptr(&command));
1568 packet_start(SSH_CMSG_EXEC_CMD);
1569 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1570 packet_send();
1571 packet_write_wait();
1572 } else {
1573 debug("Requesting shell.");
1574 packet_start(SSH_CMSG_EXEC_SHELL);
1575 packet_send();
1576 packet_write_wait();
1577 }
1578
1579 /* Enter the interactive session. */
1580 return client_loop(have_tty, tty_flag ?
1581 options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1582 }
1583
1584 /* request pty/x11/agent/tcpfwd/shell for channel */
1585 static void
ssh_session2_setup(int id,int success,void * arg)1586 ssh_session2_setup(int id, int success, void *arg)
1587 {
1588 extern char **environ;
1589 const char *display;
1590 int interactive = tty_flag;
1591
1592 if (!success)
1593 return; /* No need for error message, channels code sens one */
1594
1595 display = getenv("DISPLAY");
1596 if (options.forward_x11 && display != NULL) {
1597 char *proto, *data;
1598 /* Get reasonable local authentication information. */
1599 client_x11_get_proto(display, options.xauth_location,
1600 options.forward_x11_trusted,
1601 options.forward_x11_timeout, &proto, &data);
1602 /* Request forwarding with authentication spoofing. */
1603 debug("Requesting X11 forwarding with authentication "
1604 "spoofing.");
1605 x11_request_forwarding_with_spoofing(id, display, proto,
1606 data, 1);
1607 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1608 /* XXX exit_on_forward_failure */
1609 interactive = 1;
1610 }
1611
1612 check_agent_present();
1613 if (options.forward_agent) {
1614 debug("Requesting authentication agent forwarding.");
1615 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1616 packet_send();
1617 }
1618
1619 /* Tell the packet module whether this is an interactive session. */
1620 packet_set_interactive(interactive,
1621 options.ip_qos_interactive, options.ip_qos_bulk);
1622
1623 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1624 NULL, fileno(stdin), &command, environ);
1625 }
1626
1627 /* open new channel for a session */
1628 static int
ssh_session2_open(void)1629 ssh_session2_open(void)
1630 {
1631 Channel *c;
1632 int window, packetmax, in, out, err;
1633
1634 if (stdin_null_flag) {
1635 in = open(_PATH_DEVNULL, O_RDONLY);
1636 } else {
1637 in = dup(STDIN_FILENO);
1638 }
1639 out = dup(STDOUT_FILENO);
1640 err = dup(STDERR_FILENO);
1641
1642 if (in < 0 || out < 0 || err < 0)
1643 fatal("dup() in/out/err failed");
1644
1645 /* enable nonblocking unless tty */
1646 if (!isatty(in))
1647 set_nonblock(in);
1648 if (!isatty(out))
1649 set_nonblock(out);
1650 if (!isatty(err))
1651 set_nonblock(err);
1652
1653 /*
1654 * We need to check to see what to do about buffer sizes here.
1655 * - In an HPN to non-HPN connection we want to limit the window size to
1656 * something reasonable in case the far side has the large window bug.
1657 * - In an HPN to HPN connection we want to use the max window size but
1658 * allow the user to override it.
1659 * - Lastly if HPN is disabled then use the ssh standard window size.
1660 *
1661 * We cannot just do a getsockopt() here and set the ssh window to that
1662 * as in case of autotuning of socket buffers the window would get stuck
1663 * at the initial buffer size, generally less than 96k. Therefore we
1664 * need to set the maximum ssh window size to the maximum HPN buffer
1665 * size unless the user has set TcpRcvBufPoll to no. In that case we
1666 * can just set the window to the minimum of HPN buffer size and TCP
1667 * receive buffer size.
1668 */
1669 if (tty_flag)
1670 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1671 else
1672 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT;
1673
1674 if (datafellows & SSH_BUG_LARGEWINDOW) {
1675 debug("HPN to Non-HPN Connection");
1676 } else if (options.tcp_rcv_buf_poll <= 0) {
1677 sock_get_rcvbuf(&options.hpn_buffer_size, 0);
1678 debug("HPNBufferSize set to TCP RWIN: %d",
1679 options.hpn_buffer_size);
1680 } else if (options.tcp_rcv_buf > 0) {
1681 sock_get_rcvbuf(&options.hpn_buffer_size,
1682 options.tcp_rcv_buf);
1683 debug("HPNBufferSize set to user TCPRcvBuf: %d",
1684 options.hpn_buffer_size);
1685 }
1686 debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1687 channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1688 window = options.hpn_buffer_size;
1689
1690 packetmax = CHAN_SES_PACKET_DEFAULT;
1691 if (tty_flag) {
1692 window = CHAN_SES_WINDOW_DEFAULT;
1693 window >>= 1;
1694 packetmax >>= 1;
1695 }
1696 c = channel_new(
1697 "session", SSH_CHANNEL_OPENING, in, out, err,
1698 window, packetmax, CHAN_EXTENDED_WRITE,
1699 "client-session", /*nonblock*/0);
1700 if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) {
1701 c->dynamic_window = 1;
1702 debug("Enabled Dynamic Window Scaling\n");
1703 }
1704
1705 debug3("ssh_session2_open: channel_new: %d", c->self);
1706
1707 channel_send_open(c->self);
1708 if (!no_shell_flag)
1709 channel_register_open_confirm(c->self,
1710 ssh_session2_setup, NULL);
1711
1712 return c->self;
1713 }
1714
1715 static int
ssh_session2(void)1716 ssh_session2(void)
1717 {
1718 int id = -1;
1719
1720 /* XXX should be pre-session */
1721 if (!options.control_persist)
1722 ssh_init_stdio_forwarding();
1723 ssh_init_forwarding();
1724
1725 /* Start listening for multiplex clients */
1726 muxserver_listen();
1727
1728 /*
1729 * If we are in control persist mode and have a working mux listen
1730 * socket, then prepare to background ourselves and have a foreground
1731 * client attach as a control slave.
1732 * NB. we must save copies of the flags that we override for
1733 * the backgrounding, since we defer attachment of the slave until
1734 * after the connection is fully established (in particular,
1735 * async rfwd replies have been received for ExitOnForwardFailure).
1736 */
1737 if (options.control_persist && muxserver_sock != -1) {
1738 ostdin_null_flag = stdin_null_flag;
1739 ono_shell_flag = no_shell_flag;
1740 orequest_tty = options.request_tty;
1741 otty_flag = tty_flag;
1742 stdin_null_flag = 1;
1743 no_shell_flag = 1;
1744 tty_flag = 0;
1745 if (!fork_after_authentication_flag)
1746 need_controlpersist_detach = 1;
1747 fork_after_authentication_flag = 1;
1748 }
1749 /*
1750 * ControlPersist mux listen socket setup failed, attempt the
1751 * stdio forward setup that we skipped earlier.
1752 */
1753 if (options.control_persist && muxserver_sock == -1)
1754 ssh_init_stdio_forwarding();
1755
1756 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1757 id = ssh_session2_open();
1758 else {
1759 packet_set_interactive(
1760 options.control_master == SSHCTL_MASTER_NO,
1761 options.ip_qos_interactive, options.ip_qos_bulk);
1762 }
1763
1764 /* If we don't expect to open a new session, then disallow it */
1765 if (options.control_master == SSHCTL_MASTER_NO &&
1766 (datafellows & SSH_NEW_OPENSSH)) {
1767 debug("Requesting no-more-sessions@openssh.com");
1768 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1769 packet_put_cstring("no-more-sessions@openssh.com");
1770 packet_put_char(0);
1771 packet_send();
1772 }
1773
1774 /* Execute a local command */
1775 if (options.local_command != NULL &&
1776 options.permit_local_command)
1777 ssh_local_cmd(options.local_command);
1778
1779 /*
1780 * If requested and we are not interested in replies to remote
1781 * forwarding requests, then let ssh continue in the background.
1782 */
1783 if (fork_after_authentication_flag) {
1784 if (options.exit_on_forward_failure &&
1785 options.num_remote_forwards > 0) {
1786 debug("deferring postauth fork until remote forward "
1787 "confirmation received");
1788 } else
1789 fork_postauth();
1790 }
1791
1792 if (options.use_roaming)
1793 request_roaming();
1794
1795 return client_loop(tty_flag, tty_flag ?
1796 options.escape_char : SSH_ESCAPECHAR_NONE, id);
1797 }
1798
1799 static void
load_public_identity_files(void)1800 load_public_identity_files(void)
1801 {
1802 char *filename, *cp, thishost[NI_MAXHOST];
1803 char *pwdir = NULL, *pwname = NULL;
1804 int i = 0;
1805 Key *public;
1806 struct passwd *pw;
1807 u_int n_ids;
1808 char *identity_files[SSH_MAX_IDENTITY_FILES];
1809 Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1810 #ifdef ENABLE_PKCS11
1811 Key **keys;
1812 int nkeys;
1813 #endif /* PKCS11 */
1814
1815 n_ids = 0;
1816 memset(identity_files, 0, sizeof(identity_files));
1817 memset(identity_keys, 0, sizeof(identity_keys));
1818
1819 #ifdef ENABLE_PKCS11
1820 if (options.pkcs11_provider != NULL &&
1821 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1822 (pkcs11_init(!options.batch_mode) == 0) &&
1823 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1824 &keys)) > 0) {
1825 for (i = 0; i < nkeys; i++) {
1826 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1827 key_free(keys[i]);
1828 continue;
1829 }
1830 identity_keys[n_ids] = keys[i];
1831 identity_files[n_ids] =
1832 xstrdup(options.pkcs11_provider); /* XXX */
1833 n_ids++;
1834 }
1835 free(keys);
1836 }
1837 #endif /* ENABLE_PKCS11 */
1838 if ((pw = getpwuid(original_real_uid)) == NULL)
1839 fatal("load_public_identity_files: getpwuid failed");
1840 pwname = xstrdup(pw->pw_name);
1841 pwdir = xstrdup(pw->pw_dir);
1842 if (gethostname(thishost, sizeof(thishost)) == -1)
1843 fatal("load_public_identity_files: gethostname: %s",
1844 strerror(errno));
1845 for (i = 0; i < options.num_identity_files; i++) {
1846 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
1847 strcasecmp(options.identity_files[i], "none") == 0) {
1848 free(options.identity_files[i]);
1849 continue;
1850 }
1851 cp = tilde_expand_filename(options.identity_files[i],
1852 original_real_uid);
1853 filename = percent_expand(cp, "d", pwdir,
1854 "u", pwname, "l", thishost, "h", host,
1855 "r", options.user, (char *)NULL);
1856 free(cp);
1857 public = key_load_public(filename, NULL);
1858 debug("identity file %s type %d", filename,
1859 public ? public->type : -1);
1860 free(options.identity_files[i]);
1861 identity_files[n_ids] = filename;
1862 identity_keys[n_ids] = public;
1863
1864 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1865 continue;
1866
1867 /* Try to add the certificate variant too */
1868 xasprintf(&cp, "%s-cert", filename);
1869 public = key_load_public(cp, NULL);
1870 debug("identity file %s type %d", cp,
1871 public ? public->type : -1);
1872 if (public == NULL) {
1873 free(cp);
1874 continue;
1875 }
1876 if (!key_is_cert(public)) {
1877 debug("%s: key %s type %s is not a certificate",
1878 __func__, cp, key_type(public));
1879 key_free(public);
1880 free(cp);
1881 continue;
1882 }
1883 identity_keys[n_ids] = public;
1884 /* point to the original path, most likely the private key */
1885 identity_files[n_ids] = xstrdup(filename);
1886 n_ids++;
1887 }
1888 options.num_identity_files = n_ids;
1889 memcpy(options.identity_files, identity_files, sizeof(identity_files));
1890 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1891
1892 explicit_bzero(pwname, strlen(pwname));
1893 free(pwname);
1894 explicit_bzero(pwdir, strlen(pwdir));
1895 free(pwdir);
1896 }
1897
1898 static void
main_sigchld_handler(int sig)1899 main_sigchld_handler(int sig)
1900 {
1901 int save_errno = errno;
1902 pid_t pid;
1903 int status;
1904
1905 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1906 (pid < 0 && errno == EINTR))
1907 ;
1908
1909 signal(sig, main_sigchld_handler);
1910 errno = save_errno;
1911 }
1912