Move openssh-5/ to openssh/. We don't need a versioned directory.
[dragonfly.git] / crypto / openssh / ssh.c
blobe2dd67d688bdad9a74c94180a03bf5b50da3314f
1 /* $OpenBSD: ssh.c,v 1.318 2008/07/02 13:47:39 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.
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".
16 * Copyright (c) 1999 Niels Provos. All rights reserved.
17 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved.
19 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
20 * in Canada (German citizen).
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.
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.
43 #include "includes.h"
45 #include <sys/types.h>
46 #ifdef HAVE_SYS_STAT_H
47 # include <sys/stat.h>
48 #endif
49 #include <sys/resource.h>
50 #include <sys/ioctl.h>
51 #include <sys/socket.h>
53 #include <ctype.h>
54 #include <errno.h>
55 #include <fcntl.h>
56 #include <netdb.h>
57 #ifdef HAVE_PATHS_H
58 #include <paths.h>
59 #endif
60 #include <pwd.h>
61 #include <signal.h>
62 #include <stdarg.h>
63 #include <stddef.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <unistd.h>
69 #include <netinet/in.h>
70 #include <arpa/inet.h>
72 #include <openssl/evp.h>
73 #include <openssl/err.h>
74 #include "openbsd-compat/openssl-compat.h"
75 #include "openbsd-compat/sys-queue.h"
77 #include "xmalloc.h"
78 #include "ssh.h"
79 #include "ssh1.h"
80 #include "ssh2.h"
81 #include "compat.h"
82 #include "cipher.h"
83 #include "packet.h"
84 #include "buffer.h"
85 #include "channels.h"
86 #include "key.h"
87 #include "authfd.h"
88 #include "authfile.h"
89 #include "pathnames.h"
90 #include "dispatch.h"
91 #include "clientloop.h"
92 #include "log.h"
93 #include "readconf.h"
94 #include "sshconnect.h"
95 #include "misc.h"
96 #include "kex.h"
97 #include "mac.h"
98 #include "sshpty.h"
99 #include "match.h"
100 #include "msg.h"
101 #include "uidswap.h"
102 #include "version.h"
104 #ifdef SMARTCARD
105 #include "scard.h"
106 #endif
108 extern char *__progname;
110 /* Flag indicating whether debug mode is on. May be set on the command line. */
111 int debug_flag = 0;
113 /* Flag indicating whether a tty should be allocated */
114 int tty_flag = 0;
115 int no_tty_flag = 0;
116 int force_tty_flag = 0;
118 /* don't exec a shell */
119 int no_shell_flag = 0;
122 * Flag indicating that nothing should be read from stdin. This can be set
123 * on the command line.
125 int stdin_null_flag = 0;
128 * Flag indicating that ssh should fork after authentication. This is useful
129 * so that the passphrase can be entered manually, and then ssh goes to the
130 * background.
132 int fork_after_authentication_flag = 0;
135 * General data structure for command line options and options configurable
136 * in configuration files. See readconf.h.
138 Options options;
140 /* optional user configfile */
141 char *config = NULL;
144 * Name of the host we are connecting to. This is the name given on the
145 * command line, or the HostName specified for the user-supplied name in a
146 * configuration file.
148 char *host;
150 /* socket address the host resolves to */
151 struct sockaddr_storage hostaddr;
153 /* Private host keys. */
154 Sensitive sensitive_data;
156 /* Original real UID. */
157 uid_t original_real_uid;
158 uid_t original_effective_uid;
160 /* command to be executed */
161 Buffer command;
163 /* Should we execute a command or invoke a subsystem? */
164 int subsystem_flag = 0;
166 /* # of replies received for global requests */
167 static int remote_forward_confirms_received = 0;
169 /* pid of proxycommand child process */
170 pid_t proxy_command_pid = 0;
172 /* mux.c */
173 extern int muxserver_sock;
174 extern u_int muxclient_command;
176 /* Prints a help message to the user. This function never returns. */
178 static void
179 usage(void)
181 fprintf(stderr,
182 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
183 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
184 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
185 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
186 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
187 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
189 exit(255);
192 static int ssh_session(void);
193 static int ssh_session2(void);
194 static void load_public_identity_files(void);
196 /* from muxclient.c */
197 void muxclient(const char *);
198 void muxserver_listen(void);
201 * Main program for the ssh client.
204 main(int ac, char **av)
206 int i, opt, exit_status;
207 char *p, *cp, *line, buf[256];
208 struct stat st;
209 struct passwd *pw;
210 int dummy, timeout_ms;
211 extern int optind, optreset;
212 extern char *optarg;
213 struct servent *sp;
214 Forward fwd;
216 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
217 sanitise_stdfd();
219 __progname = ssh_get_progname(av[0]);
220 init_rng();
223 * Save the original real uid. It will be needed later (uid-swapping
224 * may clobber the real uid).
226 original_real_uid = getuid();
227 original_effective_uid = geteuid();
230 * Use uid-swapping to give up root privileges for the duration of
231 * option processing. We will re-instantiate the rights when we are
232 * ready to create the privileged port, and will permanently drop
233 * them when the port has been created (actually, when the connection
234 * has been made, as we may need to create the port several times).
236 PRIV_END;
238 #ifdef HAVE_SETRLIMIT
239 /* If we are installed setuid root be careful to not drop core. */
240 if (original_real_uid != original_effective_uid) {
241 struct rlimit rlim;
242 rlim.rlim_cur = rlim.rlim_max = 0;
243 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
244 fatal("setrlimit failed: %.100s", strerror(errno));
246 #endif
247 /* Get user data. */
248 pw = getpwuid(original_real_uid);
249 if (!pw) {
250 logit("You don't exist, go away!");
251 exit(255);
253 /* Take a copy of the returned structure. */
254 pw = pwcopy(pw);
257 * Set our umask to something reasonable, as some files are created
258 * with the default umask. This will make them world-readable but
259 * writable only by the owner, which is ok for all files for which we
260 * don't set the modes explicitly.
262 umask(022);
265 * Initialize option structure to indicate that no values have been
266 * set.
268 initialize_options(&options);
270 /* Parse command-line arguments. */
271 host = NULL;
273 again:
274 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
275 "ACD:F:I:KL:MNO:PR:S:TVw:XY")) != -1) {
276 switch (opt) {
277 case '1':
278 options.protocol = SSH_PROTO_1;
279 break;
280 case '2':
281 options.protocol = SSH_PROTO_2;
282 break;
283 case '4':
284 options.address_family = AF_INET;
285 break;
286 case '6':
287 options.address_family = AF_INET6;
288 break;
289 case 'n':
290 stdin_null_flag = 1;
291 break;
292 case 'f':
293 fork_after_authentication_flag = 1;
294 stdin_null_flag = 1;
295 break;
296 case 'x':
297 options.forward_x11 = 0;
298 break;
299 case 'X':
300 options.forward_x11 = 1;
301 break;
302 case 'Y':
303 options.forward_x11 = 1;
304 options.forward_x11_trusted = 1;
305 break;
306 case 'g':
307 options.gateway_ports = 1;
308 break;
309 case 'O':
310 if (strcmp(optarg, "check") == 0)
311 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
312 else if (strcmp(optarg, "exit") == 0)
313 muxclient_command = SSHMUX_COMMAND_TERMINATE;
314 else
315 fatal("Invalid multiplex command.");
316 break;
317 case 'P': /* deprecated */
318 options.use_privileged_port = 0;
319 break;
320 case 'a':
321 options.forward_agent = 0;
322 break;
323 case 'A':
324 options.forward_agent = 1;
325 break;
326 case 'k':
327 options.gss_deleg_creds = 0;
328 break;
329 case 'K':
330 options.gss_authentication = 1;
331 options.gss_deleg_creds = 1;
332 break;
333 case 'i':
334 if (stat(optarg, &st) < 0) {
335 fprintf(stderr, "Warning: Identity file %s "
336 "not accessible: %s.\n", optarg,
337 strerror(errno));
338 break;
340 if (options.num_identity_files >=
341 SSH_MAX_IDENTITY_FILES)
342 fatal("Too many identity files specified "
343 "(max %d)", SSH_MAX_IDENTITY_FILES);
344 options.identity_files[options.num_identity_files++] =
345 xstrdup(optarg);
346 break;
347 case 'I':
348 #ifdef SMARTCARD
349 options.smartcard_device = xstrdup(optarg);
350 #else
351 fprintf(stderr, "no support for smartcards.\n");
352 #endif
353 break;
354 case 't':
355 if (tty_flag)
356 force_tty_flag = 1;
357 tty_flag = 1;
358 break;
359 case 'v':
360 if (debug_flag == 0) {
361 debug_flag = 1;
362 options.log_level = SYSLOG_LEVEL_DEBUG1;
363 } else {
364 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
365 options.log_level++;
366 break;
368 /* FALLTHROUGH */
369 case 'V':
370 fprintf(stderr, "%s, %s\n",
371 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
372 if (opt == 'V')
373 exit(0);
374 break;
375 case 'w':
376 if (options.tun_open == -1)
377 options.tun_open = SSH_TUNMODE_DEFAULT;
378 options.tun_local = a2tun(optarg, &options.tun_remote);
379 if (options.tun_local == SSH_TUNID_ERR) {
380 fprintf(stderr,
381 "Bad tun device '%s'\n", optarg);
382 exit(255);
384 break;
385 case 'q':
386 options.log_level = SYSLOG_LEVEL_QUIET;
387 break;
388 case 'e':
389 if (optarg[0] == '^' && optarg[2] == 0 &&
390 (u_char) optarg[1] >= 64 &&
391 (u_char) optarg[1] < 128)
392 options.escape_char = (u_char) optarg[1] & 31;
393 else if (strlen(optarg) == 1)
394 options.escape_char = (u_char) optarg[0];
395 else if (strcmp(optarg, "none") == 0)
396 options.escape_char = SSH_ESCAPECHAR_NONE;
397 else {
398 fprintf(stderr, "Bad escape character '%s'.\n",
399 optarg);
400 exit(255);
402 break;
403 case 'c':
404 if (ciphers_valid(optarg)) {
405 /* SSH2 only */
406 options.ciphers = xstrdup(optarg);
407 options.cipher = SSH_CIPHER_INVALID;
408 } else {
409 /* SSH1 only */
410 options.cipher = cipher_number(optarg);
411 if (options.cipher == -1) {
412 fprintf(stderr,
413 "Unknown cipher type '%s'\n",
414 optarg);
415 exit(255);
417 if (options.cipher == SSH_CIPHER_3DES)
418 options.ciphers = "3des-cbc";
419 else if (options.cipher == SSH_CIPHER_BLOWFISH)
420 options.ciphers = "blowfish-cbc";
421 else
422 options.ciphers = (char *)-1;
424 break;
425 case 'm':
426 if (mac_valid(optarg))
427 options.macs = xstrdup(optarg);
428 else {
429 fprintf(stderr, "Unknown mac type '%s'\n",
430 optarg);
431 exit(255);
433 break;
434 case 'M':
435 if (options.control_master == SSHCTL_MASTER_YES)
436 options.control_master = SSHCTL_MASTER_ASK;
437 else
438 options.control_master = SSHCTL_MASTER_YES;
439 break;
440 case 'p':
441 options.port = a2port(optarg);
442 if (options.port == 0) {
443 fprintf(stderr, "Bad port '%s'\n", optarg);
444 exit(255);
446 break;
447 case 'l':
448 options.user = optarg;
449 break;
451 case 'L':
452 if (parse_forward(&fwd, optarg))
453 add_local_forward(&options, &fwd);
454 else {
455 fprintf(stderr,
456 "Bad local forwarding specification '%s'\n",
457 optarg);
458 exit(255);
460 break;
462 case 'R':
463 if (parse_forward(&fwd, optarg)) {
464 add_remote_forward(&options, &fwd);
465 } else {
466 fprintf(stderr,
467 "Bad remote forwarding specification "
468 "'%s'\n", optarg);
469 exit(255);
471 break;
473 case 'D':
474 cp = p = xstrdup(optarg);
475 memset(&fwd, '\0', sizeof(fwd));
476 fwd.connect_host = "socks";
477 if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
478 fprintf(stderr, "Bad dynamic forwarding "
479 "specification '%.100s'\n", optarg);
480 exit(255);
482 if (cp != NULL) {
483 fwd.listen_port = a2port(cp);
484 fwd.listen_host =
485 cleanhostname(fwd.listen_host);
486 } else {
487 fwd.listen_port = a2port(fwd.listen_host);
488 fwd.listen_host = NULL;
491 if (fwd.listen_port == 0) {
492 fprintf(stderr, "Bad dynamic port '%s'\n",
493 optarg);
494 exit(255);
496 add_local_forward(&options, &fwd);
497 xfree(p);
498 break;
500 case 'C':
501 options.compression = 1;
502 break;
503 case 'N':
504 no_shell_flag = 1;
505 no_tty_flag = 1;
506 break;
507 case 'T':
508 no_tty_flag = 1;
509 break;
510 case 'o':
511 dummy = 1;
512 line = xstrdup(optarg);
513 if (process_config_line(&options, host ? host : "",
514 line, "command-line", 0, &dummy) != 0)
515 exit(255);
516 xfree(line);
517 break;
518 case 's':
519 subsystem_flag = 1;
520 break;
521 case 'S':
522 if (options.control_path != NULL)
523 free(options.control_path);
524 options.control_path = xstrdup(optarg);
525 break;
526 case 'b':
527 options.bind_address = optarg;
528 break;
529 case 'F':
530 config = optarg;
531 break;
532 default:
533 usage();
537 ac -= optind;
538 av += optind;
540 if (ac > 0 && !host && **av != '-') {
541 if (strrchr(*av, '@')) {
542 p = xstrdup(*av);
543 cp = strrchr(p, '@');
544 if (cp == NULL || cp == p)
545 usage();
546 options.user = p;
547 *cp = '\0';
548 host = ++cp;
549 } else
550 host = *av;
551 if (ac > 1) {
552 optind = optreset = 1;
553 goto again;
555 ac--, av++;
558 /* Check that we got a host name. */
559 if (!host)
560 usage();
562 SSLeay_add_all_algorithms();
563 ERR_load_crypto_strings();
565 /* Initialize the command to execute on remote host. */
566 buffer_init(&command);
569 * Save the command to execute on the remote host in a buffer. There
570 * is no limit on the length of the command, except by the maximum
571 * packet size. Also sets the tty flag if there is no command.
573 if (!ac) {
574 /* No command specified - execute shell on a tty. */
575 tty_flag = 1;
576 if (subsystem_flag) {
577 fprintf(stderr,
578 "You must specify a subsystem to invoke.\n");
579 usage();
581 } else {
582 /* A command has been specified. Store it into the buffer. */
583 for (i = 0; i < ac; i++) {
584 if (i)
585 buffer_append(&command, " ", 1);
586 buffer_append(&command, av[i], strlen(av[i]));
590 /* Cannot fork to background if no command. */
591 if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
592 !no_shell_flag)
593 fatal("Cannot fork into background without a command "
594 "to execute.");
596 /* Allocate a tty by default if no command specified. */
597 if (buffer_len(&command) == 0)
598 tty_flag = 1;
600 /* Force no tty */
601 if (no_tty_flag)
602 tty_flag = 0;
603 /* Do not allocate a tty if stdin is not a tty. */
604 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
605 if (tty_flag)
606 logit("Pseudo-terminal will not be allocated because "
607 "stdin is not a terminal.");
608 tty_flag = 0;
612 * Initialize "log" output. Since we are the client all output
613 * actually goes to stderr.
615 log_init(av[0],
616 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
617 SYSLOG_FACILITY_USER, 1);
620 * Read per-user configuration file. Ignore the system wide config
621 * file if the user specifies a config file on the command line.
623 if (config != NULL) {
624 if (!read_config_file(config, host, &options, 0))
625 fatal("Can't open user config file %.100s: "
626 "%.100s", config, strerror(errno));
627 } else {
628 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
629 _PATH_SSH_USER_CONFFILE);
630 (void)read_config_file(buf, host, &options, 1);
632 /* Read systemwide configuration file after use config. */
633 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
634 &options, 0);
637 /* Fill configuration defaults. */
638 fill_default_options(&options);
640 channel_set_af(options.address_family);
642 /* reinit */
643 log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
645 seed_rng();
647 if (options.user == NULL)
648 options.user = xstrdup(pw->pw_name);
650 /* Get default port if port has not been set. */
651 if (options.port == 0) {
652 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
653 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
656 if (options.local_command != NULL) {
657 char thishost[NI_MAXHOST];
659 if (gethostname(thishost, sizeof(thishost)) == -1)
660 fatal("gethostname: %s", strerror(errno));
661 snprintf(buf, sizeof(buf), "%d", options.port);
662 debug3("expanding LocalCommand: %s", options.local_command);
663 cp = options.local_command;
664 options.local_command = percent_expand(cp, "d", pw->pw_dir,
665 "h", options.hostname? options.hostname : host,
666 "l", thishost, "n", host, "r", options.user, "p", buf,
667 "u", pw->pw_name, (char *)NULL);
668 debug3("expanded LocalCommand: %s", options.local_command);
669 xfree(cp);
672 if (options.hostname != NULL)
673 host = options.hostname;
675 /* force lowercase for hostkey matching */
676 if (options.host_key_alias != NULL) {
677 for (p = options.host_key_alias; *p; p++)
678 if (isupper(*p))
679 *p = (char)tolower(*p);
682 if (options.proxy_command != NULL &&
683 strcmp(options.proxy_command, "none") == 0) {
684 xfree(options.proxy_command);
685 options.proxy_command = NULL;
687 if (options.control_path != NULL &&
688 strcmp(options.control_path, "none") == 0) {
689 xfree(options.control_path);
690 options.control_path = NULL;
693 if (options.control_path != NULL) {
694 char thishost[NI_MAXHOST];
696 if (gethostname(thishost, sizeof(thishost)) == -1)
697 fatal("gethostname: %s", strerror(errno));
698 snprintf(buf, sizeof(buf), "%d", options.port);
699 cp = tilde_expand_filename(options.control_path,
700 original_real_uid);
701 xfree(options.control_path);
702 options.control_path = percent_expand(cp, "p", buf, "h", host,
703 "r", options.user, "l", thishost, (char *)NULL);
704 xfree(cp);
706 if (muxclient_command != 0 && options.control_path == NULL)
707 fatal("No ControlPath specified for \"-O\" command");
708 if (options.control_path != NULL)
709 muxclient(options.control_path);
711 timeout_ms = options.connection_timeout * 1000;
713 /* Open a connection to the remote host. */
714 if (ssh_connect(host, &hostaddr, options.port,
715 options.address_family, options.connection_attempts, &timeout_ms,
716 options.tcp_keep_alive,
717 #ifdef HAVE_CYGWIN
718 options.use_privileged_port,
719 #else
720 original_effective_uid == 0 && options.use_privileged_port,
721 #endif
722 options.proxy_command) != 0)
723 exit(255);
725 if (timeout_ms > 0)
726 debug3("timeout: %d ms remain after connect", timeout_ms);
729 * If we successfully made the connection, load the host private key
730 * in case we will need it later for combined rsa-rhosts
731 * authentication. This must be done before releasing extra
732 * privileges, because the file is only readable by root.
733 * If we cannot access the private keys, load the public keys
734 * instead and try to execute the ssh-keysign helper instead.
736 sensitive_data.nkeys = 0;
737 sensitive_data.keys = NULL;
738 sensitive_data.external_keysign = 0;
739 if (options.rhosts_rsa_authentication ||
740 options.hostbased_authentication) {
741 sensitive_data.nkeys = 3;
742 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
743 sizeof(Key));
745 PRIV_START;
746 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
747 _PATH_HOST_KEY_FILE, "", NULL, NULL);
748 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
749 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
750 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
751 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
752 PRIV_END;
754 if (options.hostbased_authentication == 1 &&
755 sensitive_data.keys[0] == NULL &&
756 sensitive_data.keys[1] == NULL &&
757 sensitive_data.keys[2] == NULL) {
758 sensitive_data.keys[1] = key_load_public(
759 _PATH_HOST_DSA_KEY_FILE, NULL);
760 sensitive_data.keys[2] = key_load_public(
761 _PATH_HOST_RSA_KEY_FILE, NULL);
762 sensitive_data.external_keysign = 1;
766 * Get rid of any extra privileges that we may have. We will no
767 * longer need them. Also, extra privileges could make it very hard
768 * to read identity files and other non-world-readable files from the
769 * user's home directory if it happens to be on a NFS volume where
770 * root is mapped to nobody.
772 if (original_effective_uid == 0) {
773 PRIV_START;
774 permanently_set_uid(pw);
778 * Now that we are back to our own permissions, create ~/.ssh
779 * directory if it doesn't already exist.
781 snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir,
782 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
783 if (stat(buf, &st) < 0)
784 if (mkdir(buf, 0700) < 0)
785 error("Could not create directory '%.200s'.", buf);
787 /* load options.identity_files */
788 load_public_identity_files();
790 /* Expand ~ in known host file names. */
791 /* XXX mem-leaks: */
792 options.system_hostfile =
793 tilde_expand_filename(options.system_hostfile, original_real_uid);
794 options.user_hostfile =
795 tilde_expand_filename(options.user_hostfile, original_real_uid);
796 options.system_hostfile2 =
797 tilde_expand_filename(options.system_hostfile2, original_real_uid);
798 options.user_hostfile2 =
799 tilde_expand_filename(options.user_hostfile2, original_real_uid);
801 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
803 /* Log into the remote system. Never returns if the login fails. */
804 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
805 pw, timeout_ms);
807 /* We no longer need the private host keys. Clear them now. */
808 if (sensitive_data.nkeys != 0) {
809 for (i = 0; i < sensitive_data.nkeys; i++) {
810 if (sensitive_data.keys[i] != NULL) {
811 /* Destroys contents safely */
812 debug3("clear hostkey %d", i);
813 key_free(sensitive_data.keys[i]);
814 sensitive_data.keys[i] = NULL;
817 xfree(sensitive_data.keys);
819 for (i = 0; i < options.num_identity_files; i++) {
820 if (options.identity_files[i]) {
821 xfree(options.identity_files[i]);
822 options.identity_files[i] = NULL;
824 if (options.identity_keys[i]) {
825 key_free(options.identity_keys[i]);
826 options.identity_keys[i] = NULL;
830 exit_status = compat20 ? ssh_session2() : ssh_session();
831 packet_close();
833 if (options.control_path != NULL && muxserver_sock != -1)
834 unlink(options.control_path);
837 * Send SIGHUP to proxy command if used. We don't wait() in
838 * case it hangs and instead rely on init to reap the child
840 if (proxy_command_pid > 1)
841 kill(proxy_command_pid, SIGHUP);
843 return exit_status;
846 /* Callback for remote forward global requests */
847 static void
848 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
850 Forward *rfwd = (Forward *)ctxt;
852 debug("remote forward %s for: listen %d, connect %s:%d",
853 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
854 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
855 if (type == SSH2_MSG_REQUEST_FAILURE) {
856 if (options.exit_on_forward_failure)
857 fatal("Error: remote port forwarding failed for "
858 "listen port %d", rfwd->listen_port);
859 else
860 logit("Warning: remote port forwarding failed for "
861 "listen port %d", rfwd->listen_port);
863 if (++remote_forward_confirms_received == options.num_remote_forwards) {
864 debug("All remote forwarding requests processed");
865 if (fork_after_authentication_flag) {
866 fork_after_authentication_flag = 0;
867 if (daemon(1, 1) < 0)
868 fatal("daemon() failed: %.200s",
869 strerror(errno));
874 static void
875 ssh_init_forwarding(void)
877 int success = 0;
878 int i;
880 /* Initiate local TCP/IP port forwardings. */
881 for (i = 0; i < options.num_local_forwards; i++) {
882 debug("Local connections to %.200s:%d forwarded to remote "
883 "address %.200s:%d",
884 (options.local_forwards[i].listen_host == NULL) ?
885 (options.gateway_ports ? "*" : "LOCALHOST") :
886 options.local_forwards[i].listen_host,
887 options.local_forwards[i].listen_port,
888 options.local_forwards[i].connect_host,
889 options.local_forwards[i].connect_port);
890 success += channel_setup_local_fwd_listener(
891 options.local_forwards[i].listen_host,
892 options.local_forwards[i].listen_port,
893 options.local_forwards[i].connect_host,
894 options.local_forwards[i].connect_port,
895 options.gateway_ports);
897 if (i > 0 && success != i && options.exit_on_forward_failure)
898 fatal("Could not request local forwarding.");
899 if (i > 0 && success == 0)
900 error("Could not request local forwarding.");
902 /* Initiate remote TCP/IP port forwardings. */
903 for (i = 0; i < options.num_remote_forwards; i++) {
904 debug("Remote connections from %.200s:%d forwarded to "
905 "local address %.200s:%d",
906 (options.remote_forwards[i].listen_host == NULL) ?
907 "LOCALHOST" : options.remote_forwards[i].listen_host,
908 options.remote_forwards[i].listen_port,
909 options.remote_forwards[i].connect_host,
910 options.remote_forwards[i].connect_port);
911 if (channel_request_remote_forwarding(
912 options.remote_forwards[i].listen_host,
913 options.remote_forwards[i].listen_port,
914 options.remote_forwards[i].connect_host,
915 options.remote_forwards[i].connect_port) < 0) {
916 if (options.exit_on_forward_failure)
917 fatal("Could not request remote forwarding.");
918 else
919 logit("Warning: Could not request remote "
920 "forwarding.");
922 client_register_global_confirm(ssh_confirm_remote_forward,
923 &options.remote_forwards[i]);
926 /* Initiate tunnel forwarding. */
927 if (options.tun_open != SSH_TUNMODE_NO) {
928 if (client_request_tun_fwd(options.tun_open,
929 options.tun_local, options.tun_remote) == -1) {
930 if (options.exit_on_forward_failure)
931 fatal("Could not request tunnel forwarding.");
932 else
933 error("Could not request tunnel forwarding.");
938 static void
939 check_agent_present(void)
941 if (options.forward_agent) {
942 /* Clear agent forwarding if we don't have an agent. */
943 if (!ssh_agent_present())
944 options.forward_agent = 0;
948 static int
949 ssh_session(void)
951 int type;
952 int interactive = 0;
953 int have_tty = 0;
954 struct winsize ws;
955 char *cp;
956 const char *display;
958 /* Enable compression if requested. */
959 if (options.compression) {
960 debug("Requesting compression at level %d.",
961 options.compression_level);
963 if (options.compression_level < 1 ||
964 options.compression_level > 9)
965 fatal("Compression level must be from 1 (fast) to "
966 "9 (slow, best).");
968 /* Send the request. */
969 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
970 packet_put_int(options.compression_level);
971 packet_send();
972 packet_write_wait();
973 type = packet_read();
974 if (type == SSH_SMSG_SUCCESS)
975 packet_start_compression(options.compression_level);
976 else if (type == SSH_SMSG_FAILURE)
977 logit("Warning: Remote host refused compression.");
978 else
979 packet_disconnect("Protocol error waiting for "
980 "compression response.");
982 /* Allocate a pseudo tty if appropriate. */
983 if (tty_flag) {
984 debug("Requesting pty.");
986 /* Start the packet. */
987 packet_start(SSH_CMSG_REQUEST_PTY);
989 /* Store TERM in the packet. There is no limit on the
990 length of the string. */
991 cp = getenv("TERM");
992 if (!cp)
993 cp = "";
994 packet_put_cstring(cp);
996 /* Store window size in the packet. */
997 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
998 memset(&ws, 0, sizeof(ws));
999 packet_put_int((u_int)ws.ws_row);
1000 packet_put_int((u_int)ws.ws_col);
1001 packet_put_int((u_int)ws.ws_xpixel);
1002 packet_put_int((u_int)ws.ws_ypixel);
1004 /* Store tty modes in the packet. */
1005 tty_make_modes(fileno(stdin), NULL);
1007 /* Send the packet, and wait for it to leave. */
1008 packet_send();
1009 packet_write_wait();
1011 /* Read response from the server. */
1012 type = packet_read();
1013 if (type == SSH_SMSG_SUCCESS) {
1014 interactive = 1;
1015 have_tty = 1;
1016 } else if (type == SSH_SMSG_FAILURE)
1017 logit("Warning: Remote host failed or refused to "
1018 "allocate a pseudo tty.");
1019 else
1020 packet_disconnect("Protocol error waiting for pty "
1021 "request response.");
1023 /* Request X11 forwarding if enabled and DISPLAY is set. */
1024 display = getenv("DISPLAY");
1025 if (options.forward_x11 && display != NULL) {
1026 char *proto, *data;
1027 /* Get reasonable local authentication information. */
1028 client_x11_get_proto(display, options.xauth_location,
1029 options.forward_x11_trusted, &proto, &data);
1030 /* Request forwarding with authentication spoofing. */
1031 debug("Requesting X11 forwarding with authentication "
1032 "spoofing.");
1033 x11_request_forwarding_with_spoofing(0, display, proto, data);
1035 /* Read response from the server. */
1036 type = packet_read();
1037 if (type == SSH_SMSG_SUCCESS) {
1038 interactive = 1;
1039 } else if (type == SSH_SMSG_FAILURE) {
1040 logit("Warning: Remote host denied X11 forwarding.");
1041 } else {
1042 packet_disconnect("Protocol error waiting for X11 "
1043 "forwarding");
1046 /* Tell the packet module whether this is an interactive session. */
1047 packet_set_interactive(interactive);
1049 /* Request authentication agent forwarding if appropriate. */
1050 check_agent_present();
1052 if (options.forward_agent) {
1053 debug("Requesting authentication agent forwarding.");
1054 auth_request_forwarding();
1056 /* Read response from the server. */
1057 type = packet_read();
1058 packet_check_eom();
1059 if (type != SSH_SMSG_SUCCESS)
1060 logit("Warning: Remote host denied authentication agent forwarding.");
1063 /* Initiate port forwardings. */
1064 ssh_init_forwarding();
1066 /* Execute a local command */
1067 if (options.local_command != NULL &&
1068 options.permit_local_command)
1069 ssh_local_cmd(options.local_command);
1072 * If requested and we are not interested in replies to remote
1073 * forwarding requests, then let ssh continue in the background.
1075 if (fork_after_authentication_flag &&
1076 (!options.exit_on_forward_failure ||
1077 options.num_remote_forwards == 0)) {
1078 fork_after_authentication_flag = 0;
1079 if (daemon(1, 1) < 0)
1080 fatal("daemon() failed: %.200s", strerror(errno));
1084 * If a command was specified on the command line, execute the
1085 * command now. Otherwise request the server to start a shell.
1087 if (buffer_len(&command) > 0) {
1088 int len = buffer_len(&command);
1089 if (len > 900)
1090 len = 900;
1091 debug("Sending command: %.*s", len,
1092 (u_char *)buffer_ptr(&command));
1093 packet_start(SSH_CMSG_EXEC_CMD);
1094 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1095 packet_send();
1096 packet_write_wait();
1097 } else {
1098 debug("Requesting shell.");
1099 packet_start(SSH_CMSG_EXEC_SHELL);
1100 packet_send();
1101 packet_write_wait();
1104 /* Enter the interactive session. */
1105 return client_loop(have_tty, tty_flag ?
1106 options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1109 /* request pty/x11/agent/tcpfwd/shell for channel */
1110 static void
1111 ssh_session2_setup(int id, void *arg)
1113 extern char **environ;
1114 const char *display;
1115 int interactive = tty_flag;
1117 display = getenv("DISPLAY");
1118 if (options.forward_x11 && display != NULL) {
1119 char *proto, *data;
1120 /* Get reasonable local authentication information. */
1121 client_x11_get_proto(display, options.xauth_location,
1122 options.forward_x11_trusted, &proto, &data);
1123 /* Request forwarding with authentication spoofing. */
1124 debug("Requesting X11 forwarding with authentication "
1125 "spoofing.");
1126 x11_request_forwarding_with_spoofing(id, display, proto, data);
1127 interactive = 1;
1128 /* XXX wait for reply */
1131 check_agent_present();
1132 if (options.forward_agent) {
1133 debug("Requesting authentication agent forwarding.");
1134 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1135 packet_send();
1138 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1139 NULL, fileno(stdin), &command, environ);
1141 packet_set_interactive(interactive);
1144 /* open new channel for a session */
1145 static int
1146 ssh_session2_open(void)
1148 Channel *c;
1149 int window, packetmax, in, out, err;
1151 if (stdin_null_flag) {
1152 in = open(_PATH_DEVNULL, O_RDONLY);
1153 } else {
1154 in = dup(STDIN_FILENO);
1156 out = dup(STDOUT_FILENO);
1157 err = dup(STDERR_FILENO);
1159 if (in < 0 || out < 0 || err < 0)
1160 fatal("dup() in/out/err failed");
1162 /* enable nonblocking unless tty */
1163 if (!isatty(in))
1164 set_nonblock(in);
1165 if (!isatty(out))
1166 set_nonblock(out);
1167 if (!isatty(err))
1168 set_nonblock(err);
1170 window = CHAN_SES_WINDOW_DEFAULT;
1171 packetmax = CHAN_SES_PACKET_DEFAULT;
1172 if (tty_flag) {
1173 window >>= 1;
1174 packetmax >>= 1;
1176 c = channel_new(
1177 "session", SSH_CHANNEL_OPENING, in, out, err,
1178 window, packetmax, CHAN_EXTENDED_WRITE,
1179 "client-session", /*nonblock*/0);
1181 debug3("ssh_session2_open: channel_new: %d", c->self);
1183 channel_send_open(c->self);
1184 if (!no_shell_flag)
1185 channel_register_open_confirm(c->self,
1186 ssh_session2_setup, NULL);
1188 return c->self;
1191 static int
1192 ssh_session2(void)
1194 int id = -1;
1196 /* XXX should be pre-session */
1197 ssh_init_forwarding();
1199 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1200 id = ssh_session2_open();
1202 /* If we don't expect to open a new session, then disallow it */
1203 if (options.control_master == SSHCTL_MASTER_NO) {
1204 debug("Requesting no-more-sessions@openssh.com");
1205 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1206 packet_put_cstring("no-more-sessions@openssh.com");
1207 packet_put_char(0);
1208 packet_send();
1211 /* Execute a local command */
1212 if (options.local_command != NULL &&
1213 options.permit_local_command)
1214 ssh_local_cmd(options.local_command);
1216 /* Start listening for multiplex clients */
1217 muxserver_listen();
1219 /* If requested, let ssh continue in the background. */
1220 if (fork_after_authentication_flag) {
1221 fork_after_authentication_flag = 0;
1222 if (daemon(1, 1) < 0)
1223 fatal("daemon() failed: %.200s", strerror(errno));
1226 return client_loop(tty_flag, tty_flag ?
1227 options.escape_char : SSH_ESCAPECHAR_NONE, id);
1230 static void
1231 load_public_identity_files(void)
1233 char *filename, *cp, thishost[NI_MAXHOST];
1234 char *pwdir = NULL, *pwname = NULL;
1235 int i = 0;
1236 Key *public;
1237 struct passwd *pw;
1238 #ifdef SMARTCARD
1239 Key **keys;
1241 if (options.smartcard_device != NULL &&
1242 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1243 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
1244 int count = 0;
1245 for (i = 0; keys[i] != NULL; i++) {
1246 count++;
1247 memmove(&options.identity_files[1],
1248 &options.identity_files[0],
1249 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1250 memmove(&options.identity_keys[1],
1251 &options.identity_keys[0],
1252 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1253 options.num_identity_files++;
1254 options.identity_keys[0] = keys[i];
1255 options.identity_files[0] = sc_get_key_label(keys[i]);
1257 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1258 options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1259 i = count;
1260 xfree(keys);
1262 #endif /* SMARTCARD */
1263 if ((pw = getpwuid(original_real_uid)) == NULL)
1264 fatal("load_public_identity_files: getpwuid failed");
1265 pwname = xstrdup(pw->pw_name);
1266 pwdir = xstrdup(pw->pw_dir);
1267 if (gethostname(thishost, sizeof(thishost)) == -1)
1268 fatal("load_public_identity_files: gethostname: %s",
1269 strerror(errno));
1270 for (; i < options.num_identity_files; i++) {
1271 cp = tilde_expand_filename(options.identity_files[i],
1272 original_real_uid);
1273 filename = percent_expand(cp, "d", pwdir,
1274 "u", pwname, "l", thishost, "h", host,
1275 "r", options.user, (char *)NULL);
1276 xfree(cp);
1277 public = key_load_public(filename, NULL);
1278 debug("identity file %s type %d", filename,
1279 public ? public->type : -1);
1280 xfree(options.identity_files[i]);
1281 options.identity_files[i] = filename;
1282 options.identity_keys[i] = public;
1284 bzero(pwname, strlen(pwname));
1285 xfree(pwname);
1286 bzero(pwdir, strlen(pwdir));
1287 xfree(pwdir);