1 /* $OpenBSD: ssh.c,v 1.326 2009/07/02 02:11:47 dtucker Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright © 2013
5 * Thorsten “mirabilos” Glaser <tg@mirbsd.org>
6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7 * All rights reserved
8 * Ssh client program. This program can be used to log into a remote machine.
9 * The software supports strong authentication, encryption, and forwarding
10 * of X11, TCP/IP, and authentication connections.
11 *
12 * As far as I am concerned, the code I have written for this software
13 * can be used freely for any purpose. Any derived versions of this
14 * software must be clearly marked as such, and if the derived work is
15 * incompatible with the protocol description in the RFC file, it must be
16 * called by a name other than "ssh" or "Secure Shell".
17 *
18 * Copyright (c) 1999 Niels Provos. All rights reserved.
19 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved.
20 *
21 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
22 * in Canada (German citizen).
23 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 *
33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 */
44
45 #include <sys/types.h>
46 #include <sys/time.h>
47 #include <sys/ioctl.h>
48 #include <sys/param.h>
49 #include <sys/queue.h>
50 #include <sys/resource.h>
51 #include <sys/socket.h>
52 #include <sys/stat.h>
53
54 #include <ctype.h>
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <netdb.h>
58 #include <paths.h>
59 #include <pwd.h>
60 #include <signal.h>
61 #include <stddef.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <string.h>
65 #include <unistd.h>
66
67 #include <openssl/evp.h>
68 #include <openssl/err.h>
69
70 #include "xmalloc.h"
71 #include "ssh.h"
72 #include "ssh1.h"
73 #include "ssh2.h"
74 #include "compat.h"
75 #include "cipher.h"
76 #include "packet.h"
77 #include "buffer.h"
78 #include "channels.h"
79 #include "key.h"
80 #include "authfd.h"
81 #include "authfile.h"
82 #include "pathnames.h"
83 #include "dispatch.h"
84 #include "clientloop.h"
85 #include "log.h"
86 #include "readconf.h"
87 #include "sshconnect.h"
88 #include "misc.h"
89 #include "kex.h"
90 #include "mac.h"
91 #include "sshpty.h"
92 #include "match.h"
93 #include "msg.h"
94 #include "uidswap.h"
95 #include "version.h"
96
97 #ifdef SMARTCARD
98 #include "scard.h"
99 #endif
100
101 __RCSID("$MirOS: src/usr.bin/ssh/ssh.c,v 1.30 2013/10/31 20:07:14 tg Exp $");
102
103 extern char *__progname;
104
105 /* Flag indicating whether debug mode is on. May be set on the command line. */
106 int debug_flag = 0;
107
108 /* Flag indicating whether a tty should be allocated */
109 int tty_flag = 0;
110 int no_tty_flag = 0;
111 int force_tty_flag = 0;
112
113 /* don't exec a shell */
114 int no_shell_flag = 0;
115
116 /*
117 * Flag indicating that nothing should be read from stdin. This can be set
118 * on the command line.
119 */
120 int stdin_null_flag = 0;
121
122 /*
123 * Flag indicating that ssh should fork after authentication. This is useful
124 * so that the passphrase can be entered manually, and then ssh goes to the
125 * background.
126 */
127 int fork_after_authentication_flag = 0;
128
129 /*
130 * General data structure for command line options and options configurable
131 * in configuration files. See readconf.h.
132 */
133 Options options;
134
135 /* optional user configfile */
136 char *config = NULL;
137
138 /*
139 * Name of the host we are connecting to. This is the name given on the
140 * command line, or the Hostname specified for the user-supplied name in a
141 * configuration file.
142 */
143 char *host;
144
145 /* socket address the host resolves to */
146 struct sockaddr_storage hostaddr;
147
148 /* Private host keys. */
149 Sensitive sensitive_data;
150
151 /* Original real UID. */
152 uid_t original_real_uid;
153 uid_t original_effective_uid;
154
155 /* command to be executed */
156 Buffer command;
157
158 /* Should we execute a command or invoke a subsystem? */
159 int subsystem_flag = 0;
160
161 /* # of replies received for global requests */
162 static int remote_forward_confirms_received = 0;
163
164 /* pid of proxycommand child process */
165 pid_t proxy_command_pid = 0;
166
167 /* mux.c */
168 extern int muxserver_sock;
169 extern u_int muxclient_command;
170
171
172 /* Prints a help message to the user. This function never returns. */
173
174 static __dead void
usage(void)175 usage(void)
176 {
177 fprintf(stderr,
178 "usage: ssh [-1246AaCfgMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
179 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
180 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
181 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
182 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
183 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
184 );
185 exit(255);
186 }
187
188 static int ssh_session(void);
189 static int ssh_session2(void);
190 static void load_public_identity_files(void);
191
192 /*
193 * Main program for the ssh client.
194 */
195 int
main(int ac,char ** av)196 main(int ac, char **av)
197 {
198 int i, r, opt, exit_status, use_syslog;
199 char *p, *cp, *line, *argv0, buf[MAXPATHLEN];
200 struct stat st;
201 struct passwd *pw;
202 int dummy, timeout_ms;
203 struct servent *sp;
204 Forward fwd;
205
206 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
207 sanitise_stdfd();
208
209 /*
210 * Save the original real uid. It will be needed later (uid-swapping
211 * may clobber the real uid).
212 */
213 original_real_uid = getuid();
214 original_effective_uid = geteuid();
215
216 /*
217 * Use uid-swapping to give up root privileges for the duration of
218 * option processing. We will re-instantiate the rights when we are
219 * ready to create the privileged port, and will permanently drop
220 * them when the port has been created (actually, when the connection
221 * has been made, as we may need to create the port several times).
222 */
223 PRIV_END;
224
225 /* If we are installed setuid root be careful to not drop core. */
226 if (original_real_uid != original_effective_uid) {
227 struct rlimit rlim;
228 rlim.rlim_cur = rlim.rlim_max = 0;
229 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
230 fatal("setrlimit failed: %.100s", strerror(errno));
231 }
232 /* Get user data. */
233 pw = getpwuid(original_real_uid);
234 if (!pw) {
235 logit("You don't exist, go away!");
236 exit(255);
237 }
238 /* Take a copy of the returned structure. */
239 pw = pwcopy(pw);
240
241 /*
242 * Set our umask to something reasonable, as some files are created
243 * with the default umask. This will make them world-readable but
244 * writable only by the owner, which is ok for all files for which we
245 * don't set the modes explicitly.
246 */
247 umask(022);
248
249 /*
250 * Initialize option structure to indicate that no values have been
251 * set.
252 */
253 initialize_options(&options);
254
255 /* Parse command-line arguments. */
256 host = NULL;
257 use_syslog = 0;
258 argv0 = av[0];
259
260 again:
261 while ((opt = getopt(ac, av, "1246ab:c:e:fghi:kl:m:no:p:qstvx"
262 "ACD:F:I:KL:MNO:PR:S:TVw:XYy")) != -1) {
263 switch (opt) {
264 case '1':
265 options.protocol = SSH_PROTO_1;
266 break;
267 case '2':
268 options.protocol = SSH_PROTO_2;
269 break;
270 case '4':
271 options.address_family = AF_INET;
272 break;
273 case '6':
274 options.address_family = AF_INET6;
275 break;
276 case 'n':
277 stdin_null_flag = 1;
278 break;
279 case 'f':
280 fork_after_authentication_flag = 1;
281 stdin_null_flag = 1;
282 break;
283 case 'x':
284 options.forward_x11 = 0;
285 break;
286 case 'X':
287 options.forward_x11 = 1;
288 break;
289 case 'y':
290 use_syslog = 1;
291 break;
292 case 'Y':
293 options.forward_x11 = 1;
294 options.forward_x11_trusted = 1;
295 break;
296 case 'g':
297 options.gateway_ports = 1;
298 break;
299 case 'O':
300 if (strcmp(optarg, "check") == 0)
301 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
302 else if (strcmp(optarg, "exit") == 0)
303 muxclient_command = SSHMUX_COMMAND_TERMINATE;
304 else
305 fatal("Invalid multiplex command.");
306 break;
307 case 'P': /* deprecated */
308 options.use_privileged_port = 0;
309 break;
310 case 'a':
311 options.forward_agent = 0;
312 break;
313 case 'A':
314 options.forward_agent = 1;
315 break;
316 case 'k':
317 case 'K':
318 break;
319 case 'i':
320 if (stat(optarg, &st) < 0) {
321 fprintf(stderr, "Warning: Identity file %s "
322 "not accessible: %s.\n", optarg,
323 strerror(errno));
324 break;
325 }
326 if (options.num_identity_files >=
327 SSH_MAX_IDENTITY_FILES)
328 fatal("Too many identity files specified "
329 "(max %d)", SSH_MAX_IDENTITY_FILES);
330 options.identity_files[options.num_identity_files++] =
331 xstrdup(optarg);
332 break;
333 case 'I':
334 #ifdef SMARTCARD
335 options.smartcard_device = xstrdup(optarg);
336 #else
337 fprintf(stderr, "no support for smartcards.\n");
338 #endif
339 break;
340 case 't':
341 if (tty_flag)
342 force_tty_flag = 1;
343 tty_flag = 1;
344 break;
345 case 'v':
346 if (debug_flag == 0) {
347 debug_flag = 1;
348 options.log_level = SYSLOG_LEVEL_DEBUG1;
349 } else {
350 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
351 options.log_level++;
352 break;
353 }
354 /* FALLTHROUGH */
355 case 'V':
356 fprintf(stderr, "%s, %s\n",
357 SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
358 if (opt == 'V')
359 exit(0);
360 break;
361 case 'w':
362 if (options.tun_open == -1)
363 options.tun_open = SSH_TUNMODE_DEFAULT;
364 options.tun_local = a2tun(optarg, &options.tun_remote);
365 if (options.tun_local == SSH_TUNID_ERR) {
366 fprintf(stderr,
367 "Bad tun device '%s'\n", optarg);
368 exit(255);
369 }
370 break;
371 case 'q':
372 options.log_level = SYSLOG_LEVEL_QUIET;
373 break;
374 case 'e':
375 if (optarg[0] == '^' && optarg[2] == 0 &&
376 (u_char) optarg[1] >= 64 &&
377 (u_char) optarg[1] < 128)
378 options.escape_char = (u_char) optarg[1] & 31;
379 else if (strlen(optarg) == 1)
380 options.escape_char = (u_char) optarg[0];
381 else if (strcmp(optarg, "none") == 0)
382 options.escape_char = SSH_ESCAPECHAR_NONE;
383 else {
384 fprintf(stderr, "Bad escape character '%s'.\n",
385 optarg);
386 exit(255);
387 }
388 break;
389 case 'c':
390 if (ciphers_valid(optarg)) {
391 /* SSH2 only */
392 options.ciphers = xstrdup(optarg);
393 options.cipher = SSH_CIPHER_INVALID;
394 } else {
395 /* SSH1 only */
396 options.cipher = cipher_number(optarg);
397 if (options.cipher == -1) {
398 fprintf(stderr,
399 "Unknown cipher type '%s'\n",
400 optarg);
401 exit(255);
402 }
403 if (options.cipher == SSH_CIPHER_3DES)
404 options.ciphers = "3des-cbc";
405 else if (options.cipher == SSH_CIPHER_BLOWFISH)
406 options.ciphers = "blowfish-cbc";
407 else
408 options.ciphers = (const char *)-1;
409 }
410 break;
411 case 'm':
412 if (mac_valid(optarg))
413 options.macs = xstrdup(optarg);
414 else {
415 fprintf(stderr, "Unknown mac type '%s'\n",
416 optarg);
417 exit(255);
418 }
419 break;
420 case 'M':
421 if (options.control_master == SSHCTL_MASTER_YES)
422 options.control_master = SSHCTL_MASTER_ASK;
423 else
424 options.control_master = SSHCTL_MASTER_YES;
425 break;
426 case 'p':
427 options.port = a2port(optarg);
428 if (options.port <= 0) {
429 fprintf(stderr, "Bad port '%s'\n", optarg);
430 exit(255);
431 }
432 break;
433 case 'l':
434 options.user = optarg;
435 break;
436
437 case 'L':
438 if (parse_forward(&fwd, optarg, 0, 0))
439 add_local_forward(&options, &fwd);
440 else {
441 fprintf(stderr,
442 "Bad local forwarding specification '%s'\n",
443 optarg);
444 exit(255);
445 }
446 break;
447
448 case 'R':
449 if (parse_forward(&fwd, optarg, 0, 1)) {
450 add_remote_forward(&options, &fwd);
451 } else {
452 fprintf(stderr,
453 "Bad remote forwarding specification "
454 "'%s'\n", optarg);
455 exit(255);
456 }
457 break;
458
459 case 'D':
460 if (parse_forward(&fwd, optarg, 1, 0)) {
461 add_local_forward(&options, &fwd);
462 } else {
463 fprintf(stderr,
464 "Bad dynamic forwarding specification "
465 "'%s'\n", optarg);
466 exit(255);
467 }
468 break;
469
470 case 'C':
471 options.compression = 1;
472 break;
473 case 'N':
474 no_shell_flag = 1;
475 no_tty_flag = 1;
476 break;
477 case 'T':
478 no_tty_flag = 1;
479 break;
480 case 'o':
481 dummy = 1;
482 line = xstrdup(optarg);
483 if (process_config_line(&options, host ? host : "",
484 line, "command-line", 0, &dummy) != 0)
485 exit(255);
486 xfree(line);
487 break;
488 case 's':
489 subsystem_flag = 1;
490 break;
491 case 'S':
492 if (options.control_path != NULL)
493 free(options.control_path);
494 options.control_path = xstrdup(optarg);
495 break;
496 case 'b':
497 options.bind_address = optarg;
498 break;
499 case 'F':
500 config = optarg;
501 break;
502 case 'h':
503 break; /* compatibility to MirOS #8 */
504 default:
505 usage();
506 }
507 }
508
509 ac -= optind;
510 av += optind;
511
512 if (ac > 0 && !host && **av != '-') {
513 if (strrchr(*av, '@')) {
514 p = xstrdup(*av);
515 cp = strrchr(p, '@');
516 if (cp == NULL || cp == p)
517 usage();
518 options.user = p;
519 *cp = '\0';
520 host = ++cp;
521 } else
522 host = *av;
523 if (ac > 1) {
524 optind = optreset = 1;
525 goto again;
526 }
527 ac--, av++;
528 }
529
530 /* Check that we got a host name. */
531 if (!host)
532 usage();
533
534 SSLeay_add_all_algorithms();
535 ERR_load_crypto_strings();
536
537 /* Initialize the command to execute on remote host. */
538 buffer_init(&command);
539
540 /*
541 * Save the command to execute on the remote host in a buffer. There
542 * is no limit on the length of the command, except by the maximum
543 * packet size. Also sets the tty flag if there is no command.
544 */
545 if (!ac) {
546 /* No command specified - execute shell on a tty. */
547 tty_flag = 1;
548 if (subsystem_flag) {
549 fprintf(stderr,
550 "You must specify a subsystem to invoke.\n");
551 usage();
552 }
553 } else {
554 /* A command has been specified. Store it into the buffer. */
555 for (i = 0; i < ac; i++) {
556 if (i)
557 buffer_append(&command, " ", 1);
558 buffer_append(&command, av[i], strlen(av[i]));
559 }
560 }
561
562 /* Cannot fork to background if no command. */
563 if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
564 !no_shell_flag)
565 fatal("Cannot fork into background without a command "
566 "to execute.");
567
568 /* Allocate a tty by default if no command specified. */
569 if (buffer_len(&command) == 0)
570 tty_flag = 1;
571
572 /* Force no tty */
573 if (no_tty_flag)
574 tty_flag = 0;
575 /* Do not allocate a tty if stdin is not a tty. */
576 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
577 if (tty_flag)
578 logit("Pseudo-terminal will not be allocated because "
579 "stdin is not a terminal.");
580 tty_flag = 0;
581 }
582
583 /*
584 * Initialize "log" output. Since we are the client all output
585 * actually goes to stderr.
586 */
587 log_init(argv0,
588 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
589 SYSLOG_FACILITY_USER, !use_syslog);
590
591 /*
592 * Read per-user configuration file. Ignore the system wide config
593 * file if the user specifies a config file on the command line.
594 */
595 if (config != NULL) {
596 if (!read_config_file(config, host, &options, 0))
597 fatal("Can't open user config file %.100s: "
598 "%.100s", config, strerror(errno));
599 } else {
600 if (!pw->pw_dir || !pw->pw_dir[0] || (pw->pw_dir[0] == '/' &&
601 !pw->pw_dir[1]))
602 r = snprintf(buf, sizeof(buf), "%s",
603 _PATH_SSH_ROOT_CONFFILE);
604 else
605 r = snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
606 _PATH_SSH_USER_CONFFILE);
607 if (r > 0 && (size_t)r < sizeof(buf))
608 (void)read_config_file(buf, host, &options, 1);
609
610 /* Read systemwide configuration file after use config. */
611 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
612 &options, 0);
613 }
614
615 /* Fill configuration defaults. */
616 fill_default_options(&options, pw);
617
618 channel_set_af(options.address_family);
619
620 /* reinit */
621 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
622
623 if (options.user == NULL)
624 options.user = xstrdup(pw->pw_name);
625
626 /* Get default port if port has not been set. */
627 if (options.port == 0) {
628 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
629 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
630 }
631
632 if (options.local_command != NULL) {
633 char thishost[NI_MAXHOST];
634
635 if (gethostname(thishost, sizeof(thishost)) == -1)
636 fatal("gethostname: %s", strerror(errno));
637 snprintf(buf, sizeof(buf), "%d", options.port);
638 debug3("expanding LocalCommand: %s", options.local_command);
639 cp = options.local_command;
640 options.local_command = percent_expand(cp, "d", pw->pw_dir,
641 "h", options.hostname? options.hostname : host,
642 "l", thishost, "n", host, "r", options.user, "p", buf,
643 "u", pw->pw_name, (char *)NULL);
644 debug3("expanded LocalCommand: %s", options.local_command);
645 xfree(cp);
646 }
647
648 if (options.hostname != NULL)
649 host = options.hostname;
650
651 /* force lowercase for hostkey matching */
652 if (options.host_key_alias != NULL) {
653 for (p = options.host_key_alias; *p; p++)
654 if (isupper(*p))
655 *p = (char)tolower(*p);
656 }
657
658 if (options.proxy_command != NULL &&
659 strcmp(options.proxy_command, "none") == 0) {
660 xfree(options.proxy_command);
661 options.proxy_command = NULL;
662 }
663 if (options.control_path != NULL &&
664 strcmp(options.control_path, "none") == 0) {
665 xfree(options.control_path);
666 options.control_path = NULL;
667 }
668
669 if (options.control_path != NULL) {
670 char thishost[NI_MAXHOST];
671
672 if (gethostname(thishost, sizeof(thishost)) == -1)
673 fatal("gethostname: %s", strerror(errno));
674 snprintf(buf, sizeof(buf), "%d", options.port);
675 cp = tilde_expand_filename(options.control_path,
676 original_real_uid);
677 xfree(options.control_path);
678 options.control_path = percent_expand(cp, "p", buf, "h", host,
679 "r", options.user, "l", thishost, (char *)NULL);
680 xfree(cp);
681 }
682 if (muxclient_command != 0 && options.control_path == NULL)
683 fatal("No ControlPath specified for \"-O\" command");
684 if (options.control_path != NULL)
685 muxclient(options.control_path);
686
687 timeout_ms = options.connection_timeout * 1000;
688
689 /* Open a connection to the remote host. */
690 if (ssh_connect(host, &hostaddr, options.port,
691 options.address_family, options.connection_attempts, &timeout_ms,
692 options.tcp_keep_alive,
693 original_effective_uid == 0 && options.use_privileged_port,
694 options.proxy_command) != 0)
695 exit(255);
696
697 if (timeout_ms > 0)
698 debug3("timeout: %d ms remain after connect", timeout_ms);
699
700 /*
701 * If we successfully made the connection, load the host private key
702 * in case we will need it later for combined rsa-rhosts
703 * authentication. This must be done before releasing extra
704 * privileges, because the file is only readable by root.
705 * If we cannot access the private keys, load the public keys
706 * instead and try to execute the ssh-keysign helper instead.
707 */
708 sensitive_data.nkeys = 0;
709 sensitive_data.keys = NULL;
710 sensitive_data.external_keysign = 0;
711 if (options.rhosts_rsa_authentication ||
712 options.hostbased_authentication) {
713 sensitive_data.nkeys = 3;
714 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
715 sizeof(Key));
716
717 PRIV_START;
718 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
719 _PATH_HOST_KEY_FILE, "", NULL, NULL);
720 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
721 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
722 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
723 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
724 PRIV_END;
725
726 if (options.hostbased_authentication == 1 &&
727 sensitive_data.keys[0] == NULL &&
728 sensitive_data.keys[1] == NULL &&
729 sensitive_data.keys[2] == NULL) {
730 sensitive_data.keys[1] = key_load_public(
731 _PATH_HOST_DSA_KEY_FILE, NULL);
732 sensitive_data.keys[2] = key_load_public(
733 _PATH_HOST_RSA_KEY_FILE, NULL);
734 sensitive_data.external_keysign = 1;
735 }
736 }
737 /*
738 * Get rid of any extra privileges that we may have. We will no
739 * longer need them. Also, extra privileges could make it very hard
740 * to read identity files and other non-world-readable files from the
741 * user's home directory if it happens to be on a NFS volume where
742 * root is mapped to nobody.
743 */
744 if (original_effective_uid == 0) {
745 PRIV_START;
746 permanently_set_uid(pw);
747 }
748
749 /*
750 * Now that we are back to our own permissions, create ~/.etc/ssh
751 * directory if it doesn't already exist.
752 * XXX create ~/.etc first?
753 */
754 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
755 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
756 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0)
757 if (mkdir(buf, 0700) < 0)
758 error("Could not create directory '%.200s'.", buf);
759
760 /* load options.identity_files */
761 load_public_identity_files();
762
763 /* Expand ~ in known host file names. */
764 /* XXX mem-leaks: */
765 options.system_hostfile =
766 tilde_expand_filename(options.system_hostfile, original_real_uid);
767 options.user_hostfile =
768 tilde_expand_filename(options.user_hostfile, original_real_uid);
769 options.system_hostfile2 =
770 tilde_expand_filename(options.system_hostfile2, original_real_uid);
771 options.user_hostfile2 =
772 tilde_expand_filename(options.user_hostfile2, original_real_uid);
773
774 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
775
776 /* Log into the remote system. Never returns if the login fails. */
777 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
778 pw, timeout_ms);
779
780 /* We no longer need the private host keys. Clear them now. */
781 if (sensitive_data.nkeys != 0) {
782 for (i = 0; i < sensitive_data.nkeys; i++) {
783 if (sensitive_data.keys[i] != NULL) {
784 /* Destroys contents safely */
785 debug3("clear hostkey %d", i);
786 key_free(sensitive_data.keys[i]);
787 sensitive_data.keys[i] = NULL;
788 }
789 }
790 xfree(sensitive_data.keys);
791 }
792 for (i = 0; i < options.num_identity_files; i++) {
793 if (options.identity_files[i]) {
794 xfree(options.identity_files[i]);
795 options.identity_files[i] = NULL;
796 }
797 if (options.identity_keys[i]) {
798 key_free(options.identity_keys[i]);
799 options.identity_keys[i] = NULL;
800 }
801 }
802
803 exit_status = compat20 ? ssh_session2() : ssh_session();
804 packet_close();
805
806 if (options.control_path != NULL && muxserver_sock != -1)
807 unlink(options.control_path);
808
809 /*
810 * Send SIGHUP to proxy command if used. We don't wait() in
811 * case it hangs and instead rely on init to reap the child
812 */
813 if (proxy_command_pid > 1)
814 kill(proxy_command_pid, SIGHUP);
815
816 return exit_status;
817 }
818
819 /* Callback for remote forward global requests */
820 static void
ssh_confirm_remote_forward(int type,u_int32_t seq,void * ctxt)821 ssh_confirm_remote_forward(int type, u_int32_t seq __attribute__((__unused__)),
822 void *ctxt)
823 {
824 Forward *rfwd = (Forward *)ctxt;
825
826 /* XXX verbose() on failure? */
827 debug("remote forward %s for: listen %d, connect %s:%d",
828 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
829 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
830 if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) {
831 logit("Allocated port %u for remote forward to %s:%d",
832 packet_get_int(),
833 rfwd->connect_host, rfwd->connect_port);
834 }
835
836 if (type == SSH2_MSG_REQUEST_FAILURE) {
837 if (options.exit_on_forward_failure)
838 fatal("Error: remote port forwarding failed for "
839 "listen port %d", rfwd->listen_port);
840 else
841 logit("Warning: remote port forwarding failed for "
842 "listen port %d", rfwd->listen_port);
843 }
844 if (++remote_forward_confirms_received == options.num_remote_forwards) {
845 debug("All remote forwarding requests processed");
846 if (fork_after_authentication_flag) {
847 fork_after_authentication_flag = 0;
848 if (daemon(1, 1) < 0)
849 fatal("daemon() failed: %.200s",
850 strerror(errno));
851 }
852 }
853 }
854
855 static void
ssh_init_forwarding(void)856 ssh_init_forwarding(void)
857 {
858 int success = 0;
859 int i;
860
861 /* Initiate local TCP/IP port forwardings. */
862 for (i = 0; i < options.num_local_forwards; i++) {
863 debug("Local connections to %.200s:%d forwarded to remote "
864 "address %.200s:%d",
865 (options.local_forwards[i].listen_host == NULL) ?
866 (options.gateway_ports ? "*" : "LOCALHOST") :
867 options.local_forwards[i].listen_host,
868 options.local_forwards[i].listen_port,
869 options.local_forwards[i].connect_host,
870 options.local_forwards[i].connect_port);
871 success += channel_setup_local_fwd_listener(
872 options.local_forwards[i].listen_host,
873 options.local_forwards[i].listen_port,
874 options.local_forwards[i].connect_host,
875 options.local_forwards[i].connect_port,
876 options.gateway_ports);
877 }
878 if (i > 0 && success != i && options.exit_on_forward_failure)
879 fatal("Could not request local forwarding.");
880 if (i > 0 && success == 0)
881 error("Could not request local forwarding.");
882
883 /* Initiate remote TCP/IP port forwardings. */
884 for (i = 0; i < options.num_remote_forwards; i++) {
885 debug("Remote connections from %.200s:%d forwarded to "
886 "local address %.200s:%d",
887 (options.remote_forwards[i].listen_host == NULL) ?
888 "LOCALHOST" : options.remote_forwards[i].listen_host,
889 options.remote_forwards[i].listen_port,
890 options.remote_forwards[i].connect_host,
891 options.remote_forwards[i].connect_port);
892 if (channel_request_remote_forwarding(
893 options.remote_forwards[i].listen_host,
894 options.remote_forwards[i].listen_port,
895 options.remote_forwards[i].connect_host,
896 options.remote_forwards[i].connect_port) < 0) {
897 if (options.exit_on_forward_failure)
898 fatal("Could not request remote forwarding.");
899 else
900 logit("Warning: Could not request remote "
901 "forwarding.");
902 }
903 client_register_global_confirm(ssh_confirm_remote_forward,
904 &options.remote_forwards[i]);
905 }
906
907 /* Initiate tunnel forwarding. */
908 if (options.tun_open != SSH_TUNMODE_NO) {
909 if (client_request_tun_fwd(options.tun_open,
910 options.tun_local, options.tun_remote) == -1) {
911 if (options.exit_on_forward_failure)
912 fatal("Could not request tunnel forwarding.");
913 else
914 error("Could not request tunnel forwarding.");
915 }
916 }
917 }
918
919 static void
check_agent_present(void)920 check_agent_present(void)
921 {
922 if (options.forward_agent) {
923 /* Clear agent forwarding if we don't have an agent. */
924 if (!ssh_agent_present())
925 options.forward_agent = 0;
926 }
927 }
928
929 static int
ssh_session(void)930 ssh_session(void)
931 {
932 int type;
933 int interactive = 0;
934 int have_tty = 0;
935 struct winsize ws;
936 const char *cp;
937 const char *display;
938
939 /* Enable compression if requested. */
940 if (options.compression) {
941 debug("Requesting compression at level %d.",
942 options.compression_level);
943
944 if (options.compression_level < 1 ||
945 options.compression_level > 9)
946 fatal("Compression level must be from 1 (fast) to "
947 "9 (slow, best).");
948
949 /* Send the request. */
950 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
951 packet_put_int(options.compression_level);
952 packet_send();
953 packet_write_wait();
954 type = packet_read();
955 if (type == SSH_SMSG_SUCCESS)
956 packet_start_compression(options.compression_level);
957 else if (type == SSH_SMSG_FAILURE)
958 logit("Warning: Remote host refused compression.");
959 else
960 packet_disconnect("Protocol error waiting for "
961 "compression response.");
962 }
963 /* Allocate a pseudo tty if appropriate. */
964 if (tty_flag) {
965 debug("Requesting pty.");
966
967 /* Start the packet. */
968 packet_start(SSH_CMSG_REQUEST_PTY);
969
970 /* Store TERM in the packet. There is no limit on the
971 length of the string. */
972 cp = getenv("TERM");
973 if (!cp)
974 cp = "";
975 packet_put_cstring(cp);
976
977 /* Store window size in the packet. */
978 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
979 memset(&ws, 0, sizeof(ws));
980 packet_put_int((u_int)ws.ws_row);
981 packet_put_int((u_int)ws.ws_col);
982 packet_put_int((u_int)ws.ws_xpixel);
983 packet_put_int((u_int)ws.ws_ypixel);
984
985 /* Store tty modes in the packet. */
986 tty_make_modes(fileno(stdin), NULL);
987
988 /* Send the packet, and wait for it to leave. */
989 packet_send();
990 packet_write_wait();
991
992 /* Read response from the server. */
993 type = packet_read();
994 if (type == SSH_SMSG_SUCCESS) {
995 interactive = 1;
996 have_tty = 1;
997 } else if (type == SSH_SMSG_FAILURE)
998 logit("Warning: Remote host failed or refused to "
999 "allocate a pseudo tty.");
1000 else
1001 packet_disconnect("Protocol error waiting for pty "
1002 "request response.");
1003 }
1004 /* Request X11 forwarding if enabled and DISPLAY is set. */
1005 display = getenv("DISPLAY");
1006 if (options.forward_x11 && display != NULL) {
1007 char *proto, *data;
1008 /* Get reasonable local authentication information. */
1009 client_x11_get_proto(display, options.xauth_location,
1010 options.forward_x11_trusted, &proto, &data);
1011 /* Request forwarding with authentication spoofing. */
1012 debug("Requesting X11 forwarding with authentication "
1013 "spoofing.");
1014 x11_request_forwarding_with_spoofing(0, display, proto, data);
1015
1016 /* Read response from the server. */
1017 type = packet_read();
1018 if (type == SSH_SMSG_SUCCESS) {
1019 interactive = 1;
1020 } else if (type == SSH_SMSG_FAILURE) {
1021 logit("Warning: Remote host denied X11 forwarding.");
1022 } else {
1023 packet_disconnect("Protocol error waiting for X11 "
1024 "forwarding");
1025 }
1026 }
1027 /* Tell the packet module whether this is an interactive session. */
1028 packet_set_interactive(interactive);
1029
1030 /* Request authentication agent forwarding if appropriate. */
1031 check_agent_present();
1032
1033 if (options.forward_agent) {
1034 debug("Requesting authentication agent forwarding.");
1035 auth_request_forwarding();
1036
1037 /* Read response from the server. */
1038 type = packet_read();
1039 packet_check_eom();
1040 if (type != SSH_SMSG_SUCCESS)
1041 logit("Warning: Remote host denied authentication agent forwarding.");
1042 }
1043
1044 /* Initiate port forwardings. */
1045 ssh_init_forwarding();
1046
1047 /* Execute a local command */
1048 if (options.local_command != NULL &&
1049 options.permit_local_command)
1050 ssh_local_cmd(options.local_command);
1051
1052 /*
1053 * If requested and we are not interested in replies to remote
1054 * forwarding requests, then let ssh continue in the background.
1055 */
1056 if (fork_after_authentication_flag &&
1057 (!options.exit_on_forward_failure ||
1058 options.num_remote_forwards == 0)) {
1059 fork_after_authentication_flag = 0;
1060 if (daemon(1, 1) < 0)
1061 fatal("daemon() failed: %.200s", strerror(errno));
1062 }
1063
1064 /*
1065 * If a command was specified on the command line, execute the
1066 * command now. Otherwise request the server to start a shell.
1067 */
1068 if (buffer_len(&command) > 0) {
1069 int len = buffer_len(&command);
1070 if (len > 900)
1071 len = 900;
1072 debug("Sending command: %.*s", len,
1073 (u_char *)buffer_ptr(&command));
1074 packet_start(SSH_CMSG_EXEC_CMD);
1075 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1076 packet_send();
1077 packet_write_wait();
1078 } else {
1079 debug("Requesting shell.");
1080 packet_start(SSH_CMSG_EXEC_SHELL);
1081 packet_send();
1082 packet_write_wait();
1083 }
1084
1085 /* Enter the interactive session. */
1086 return client_loop(have_tty, tty_flag ?
1087 options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1088 }
1089
1090 /* request pty/x11/agent/tcpfwd/shell for channel */
1091 static void
ssh_session2_setup(int id,void * arg)1092 ssh_session2_setup(int id, void *arg __attribute__((__unused__)))
1093 {
1094 extern char **environ;
1095 const char *display;
1096 int interactive = tty_flag;
1097
1098 display = getenv("DISPLAY");
1099 if (options.forward_x11 && display != NULL) {
1100 char *proto, *data;
1101 /* Get reasonable local authentication information. */
1102 client_x11_get_proto(display, options.xauth_location,
1103 options.forward_x11_trusted, &proto, &data);
1104 /* Request forwarding with authentication spoofing. */
1105 debug("Requesting X11 forwarding with authentication "
1106 "spoofing.");
1107 x11_request_forwarding_with_spoofing(id, display, proto, data);
1108 interactive = 1;
1109 /* XXX wait for reply */
1110 }
1111
1112 check_agent_present();
1113 if (options.forward_agent) {
1114 debug("Requesting authentication agent forwarding.");
1115 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1116 packet_send();
1117 }
1118
1119 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1120 NULL, fileno(stdin), &command, environ);
1121
1122 packet_set_interactive(interactive);
1123 }
1124
1125 /* open new channel for a session */
1126 static int
ssh_session2_open(void)1127 ssh_session2_open(void)
1128 {
1129 Channel *c;
1130 int window, packetmax, in, out, err;
1131
1132 if (stdin_null_flag) {
1133 in = open(_PATH_DEVNULL, O_RDONLY);
1134 } else {
1135 in = dup(STDIN_FILENO);
1136 }
1137 out = dup(STDOUT_FILENO);
1138 err = dup(STDERR_FILENO);
1139
1140 if (in < 0 || out < 0 || err < 0)
1141 fatal("dup() in/out/err failed");
1142
1143 /* enable nonblocking unless tty */
1144 if (!isatty(in))
1145 set_nonblock(in);
1146 if (!isatty(out))
1147 set_nonblock(out);
1148 if (!isatty(err))
1149 set_nonblock(err);
1150
1151 window = CHAN_SES_WINDOW_DEFAULT;
1152 packetmax = CHAN_SES_PACKET_DEFAULT;
1153 if (tty_flag) {
1154 window >>= 1;
1155 packetmax >>= 1;
1156 }
1157 c = channel_new(
1158 "session", SSH_CHANNEL_OPENING, in, out, err,
1159 window, packetmax, CHAN_EXTENDED_WRITE,
1160 "client-session", /*nonblock*/0);
1161
1162 debug3("ssh_session2_open: channel_new: %d", c->self);
1163
1164 channel_send_open(c->self);
1165 if (!no_shell_flag)
1166 channel_register_open_confirm(c->self,
1167 ssh_session2_setup, NULL);
1168
1169 return c->self;
1170 }
1171
1172 static int
ssh_session2(void)1173 ssh_session2(void)
1174 {
1175 int id = -1;
1176
1177 /* XXX should be pre-session */
1178 ssh_init_forwarding();
1179
1180 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1181 id = ssh_session2_open();
1182
1183 /* If we don't expect to open a new session, then disallow it */
1184 if (options.control_master == SSHCTL_MASTER_NO &&
1185 (datafellows & SSH_NEW_OPENSSH)) {
1186 debug("Requesting no-more-sessions@openssh.com");
1187 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1188 packet_put_cstring("no-more-sessions@openssh.com");
1189 packet_put_char(0);
1190 packet_send();
1191 }
1192
1193 /* Execute a local command */
1194 if (options.local_command != NULL &&
1195 options.permit_local_command)
1196 ssh_local_cmd(options.local_command);
1197
1198 /* Start listening for multiplex clients */
1199 muxserver_listen();
1200
1201 /* If requested, let ssh continue in the background. */
1202 if (fork_after_authentication_flag) {
1203 fork_after_authentication_flag = 0;
1204 if (daemon(1, 1) < 0)
1205 fatal("daemon() failed: %.200s", strerror(errno));
1206 }
1207
1208 return client_loop(tty_flag, tty_flag ?
1209 options.escape_char : SSH_ESCAPECHAR_NONE, id);
1210 }
1211
1212 static void
load_public_identity_files(void)1213 load_public_identity_files(void)
1214 {
1215 char *filename, *cp, thishost[NI_MAXHOST];
1216 char *pwdir = NULL, *pwname = NULL;
1217 int i = 0;
1218 Key *public;
1219 struct passwd *pw;
1220 #ifdef SMARTCARD
1221 Key **keys;
1222
1223 if (options.smartcard_device != NULL &&
1224 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1225 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
1226 int count = 0;
1227 for (i = 0; keys[i] != NULL; i++) {
1228 count++;
1229 memmove(&options.identity_files[1],
1230 &options.identity_files[0],
1231 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1232 memmove(&options.identity_keys[1],
1233 &options.identity_keys[0],
1234 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1235 options.num_identity_files++;
1236 options.identity_keys[0] = keys[i];
1237 options.identity_files[0] = sc_get_key_label(keys[i]);
1238 }
1239 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1240 options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1241 i = count;
1242 xfree(keys);
1243 }
1244 #endif /* SMARTCARD */
1245 if ((pw = getpwuid(original_real_uid)) == NULL)
1246 fatal("load_public_identity_files: getpwuid failed");
1247 pwname = xstrdup(pw->pw_name);
1248 pwdir = xstrdup(pw->pw_dir);
1249 if (gethostname(thishost, sizeof(thishost)) == -1)
1250 fatal("load_public_identity_files: gethostname: %s",
1251 strerror(errno));
1252 for (; i < options.num_identity_files; i++) {
1253 cp = tilde_expand_filename(options.identity_files[i],
1254 original_real_uid);
1255 filename = percent_expand(cp, "d", pwdir,
1256 "u", pwname, "l", thishost, "h", host,
1257 "r", options.user, (char *)NULL);
1258 xfree(cp);
1259 public = key_load_public(filename, NULL);
1260 debug("identity file %s type %d", filename,
1261 public ? public->type : -1);
1262 xfree(options.identity_files[i]);
1263 options.identity_files[i] = filename;
1264 options.identity_keys[i] = public;
1265 }
1266 bzero(pwname, strlen(pwname));
1267 xfree(pwname);
1268 bzero(pwdir, strlen(pwdir));
1269 xfree(pwdir);
1270 }
1271