1 /* $OpenBSD: ssh.c,v 1.370 2012/07/06 01:47:38 djm Exp $ */
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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.
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".
17 * Copyright (c) 1999 Niels Provos. All rights reserved.
18 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved.
20 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
21 * in Canada (German citizen).
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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.
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.
47 #include <sys/types.h>
48 #ifdef HAVE_SYS_STAT_H
49 # include <sys/stat.h>
51 #include <sys/resource.h>
52 #include <sys/ioctl.h>
53 #include <sys/param.h>
54 #include <sys/socket.h>
73 #include <netinet/in.h>
74 #include <arpa/inet.h>
76 #include <openssl/evp.h>
77 #include <openssl/err.h>
78 #include "openbsd-compat/openssl-compat.h"
79 #include "openbsd-compat/sys-queue.h"
94 #include "pathnames.h"
96 #include "clientloop.h"
99 #include "sshconnect.h"
111 #include "ssh-pkcs11.h"
114 extern char *__progname;
116 /* Saves a copy of argv for setproctitle emulation */
117 #ifndef HAVE_SETPROCTITLE
118 static char **saved_av;
121 /* Flag indicating whether debug mode is on. May be set on the command line. */
124 /* Flag indicating whether a tty should be requested */
127 /* don't exec a shell */
128 int no_shell_flag = 0;
131 * Flag indicating that nothing should be read from stdin. This can be set
132 * on the command line.
134 int stdin_null_flag = 0;
137 * Flag indicating that the current process should be backgrounded and
138 * a new slave launched in the foreground for ControlPersist.
140 int need_controlpersist_detach = 0;
142 /* Copies of flags for ControlPersist foreground slave */
143 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
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
150 int fork_after_authentication_flag = 0;
152 /* forward stdio to remote host and port */
153 char *stdio_forward_host = NULL;
154 int stdio_forward_port = 0;
157 * General data structure for command line options and options configurable
158 * in configuration files. See readconf.h.
162 /* optional user configfile */
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.
172 /* socket address the host resolves to */
173 struct sockaddr_storage hostaddr;
175 /* Private host keys. */
176 Sensitive sensitive_data;
178 /* Original real UID. */
179 uid_t original_real_uid;
180 uid_t original_effective_uid;
182 /* command to be executed */
185 /* Should we execute a command or invoke a subsystem? */
186 int subsystem_flag = 0;
188 /* # of replies received for global requests */
189 static int remote_forward_confirms_received = 0;
192 extern int muxserver_sock;
193 extern u_int muxclient_command;
195 /* Prints a help message to the user. This function never returns. */
201 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
202 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
203 " [-I pkcs11] [-i identity_file]\n"
204 " [-L [bind_address:]port:host:hostport]\n"
205 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
206 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
207 " [-W host:port] [-w local_tun[:remote_tun]]\n"
208 " [user@]hostname [command]\n"
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);
218 /* from muxclient.c */
219 void muxclient(const char *);
220 void muxserver_listen(void);
222 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
224 tilde_expand_paths(char **paths, u_int num_paths)
229 for (i = 0; i < num_paths; i++) {
230 cp = tilde_expand_filename(paths[i], original_real_uid);
237 * Main program for the ssh client.
240 main(int ac, char **av)
242 int i, r, opt, exit_status, use_syslog;
243 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg;
244 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
247 int dummy, timeout_ms;
248 extern int optind, optreset;
254 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
257 __progname = ssh_get_progname(av[0]);
259 #ifndef HAVE_SETPROCTITLE
260 /* Prepare for later setproctitle emulation */
261 /* Save argv so it isn't clobbered by setproctitle() emulation */
262 saved_av = xcalloc(ac + 1, sizeof(*saved_av));
263 for (i = 0; i < ac; i++)
264 saved_av[i] = xstrdup(av[i]);
266 compat_init_setproctitle(ac, av);
271 * Discard other fds that are hanging around. These can cause problem
272 * with backgrounded ssh processes started by ControlPersist.
274 closefrom(STDERR_FILENO + 1);
277 * Save the original real uid. It will be needed later (uid-swapping
278 * may clobber the real uid).
280 original_real_uid = getuid();
281 original_effective_uid = geteuid();
284 * Use uid-swapping to give up root privileges for the duration of
285 * option processing. We will re-instantiate the rights when we are
286 * ready to create the privileged port, and will permanently drop
287 * them when the port has been created (actually, when the connection
288 * has been made, as we may need to create the port several times).
292 #ifdef HAVE_SETRLIMIT
293 /* If we are installed setuid root be careful to not drop core. */
294 if (original_real_uid != original_effective_uid) {
296 rlim.rlim_cur = rlim.rlim_max = 0;
297 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
298 fatal("setrlimit failed: %.100s", strerror(errno));
302 pw = getpwuid(original_real_uid);
304 logit("You don't exist, go away!");
307 /* Take a copy of the returned structure. */
311 * Set our umask to something reasonable, as some files are created
312 * with the default umask. This will make them world-readable but
313 * writable only by the owner, which is ok for all files for which we
314 * don't set the modes explicitly.
319 * Initialize option structure to indicate that no values have been
322 initialize_options(&options);
324 /* Parse command-line arguments. */
330 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
331 "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
334 options.protocol = SSH_PROTO_1;
337 options.protocol = SSH_PROTO_2;
340 options.address_family = AF_INET;
343 options.address_family = AF_INET6;
349 fork_after_authentication_flag = 1;
353 options.forward_x11 = 0;
356 options.forward_x11 = 1;
362 options.forward_x11 = 1;
363 options.forward_x11_trusted = 1;
366 options.gateway_ports = 1;
369 if (stdio_forward_host != NULL)
370 fatal("Cannot specify multiplexing "
372 else if (muxclient_command != 0)
373 fatal("Multiplexing command already specified");
374 if (strcmp(optarg, "check") == 0)
375 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
376 else if (strcmp(optarg, "forward") == 0)
377 muxclient_command = SSHMUX_COMMAND_FORWARD;
378 else if (strcmp(optarg, "exit") == 0)
379 muxclient_command = SSHMUX_COMMAND_TERMINATE;
380 else if (strcmp(optarg, "stop") == 0)
381 muxclient_command = SSHMUX_COMMAND_STOP;
382 else if (strcmp(optarg, "cancel") == 0)
383 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
385 fatal("Invalid multiplex command.");
387 case 'P': /* deprecated */
388 options.use_privileged_port = 0;
391 options.forward_agent = 0;
394 options.forward_agent = 1;
397 options.gss_deleg_creds = 0;
400 options.gss_authentication = 1;
401 options.gss_deleg_creds = 1;
404 if (stat(optarg, &st) < 0) {
405 fprintf(stderr, "Warning: Identity file %s "
406 "not accessible: %s.\n", optarg,
410 if (options.num_identity_files >=
411 SSH_MAX_IDENTITY_FILES)
412 fatal("Too many identity files specified "
413 "(max %d)", SSH_MAX_IDENTITY_FILES);
414 options.identity_files[options.num_identity_files++] =
419 options.pkcs11_provider = xstrdup(optarg);
421 fprintf(stderr, "no support for PKCS#11.\n");
425 if (options.request_tty == REQUEST_TTY_YES)
426 options.request_tty = REQUEST_TTY_FORCE;
428 options.request_tty = REQUEST_TTY_YES;
431 if (debug_flag == 0) {
433 options.log_level = SYSLOG_LEVEL_DEBUG1;
435 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
441 if (options.version_addendum &&
442 *options.version_addendum != '\0')
443 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
444 options.hpn_disabled ? "" : SSH_VERSION_HPN,
445 options.version_addendum,
446 SSLeay_version(SSLEAY_VERSION));
448 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE,
449 options.hpn_disabled ? "" : SSH_VERSION_HPN,
450 SSLeay_version(SSLEAY_VERSION));
455 if (options.tun_open == -1)
456 options.tun_open = SSH_TUNMODE_DEFAULT;
457 options.tun_local = a2tun(optarg, &options.tun_remote);
458 if (options.tun_local == SSH_TUNID_ERR) {
460 "Bad tun device '%s'\n", optarg);
465 if (stdio_forward_host != NULL)
466 fatal("stdio forward already specified");
467 if (muxclient_command != 0)
468 fatal("Cannot specify stdio forward with -O");
469 if (parse_forward(&fwd, optarg, 1, 0)) {
470 stdio_forward_host = fwd.listen_host;
471 stdio_forward_port = fwd.listen_port;
472 xfree(fwd.connect_host);
475 "Bad stdio forwarding specification '%s'\n",
479 options.request_tty = REQUEST_TTY_NO;
481 options.clear_forwardings = 1;
482 options.exit_on_forward_failure = 1;
485 options.log_level = SYSLOG_LEVEL_QUIET;
488 if (optarg[0] == '^' && optarg[2] == 0 &&
489 (u_char) optarg[1] >= 64 &&
490 (u_char) optarg[1] < 128)
491 options.escape_char = (u_char) optarg[1] & 31;
492 else if (strlen(optarg) == 1)
493 options.escape_char = (u_char) optarg[0];
494 else if (strcmp(optarg, "none") == 0)
495 options.escape_char = SSH_ESCAPECHAR_NONE;
497 fprintf(stderr, "Bad escape character '%s'.\n",
503 if (ciphers_valid(optarg)) {
505 options.ciphers = xstrdup(optarg);
506 options.cipher = SSH_CIPHER_INVALID;
509 options.cipher = cipher_number(optarg);
510 if (options.cipher == -1) {
512 "Unknown cipher type '%s'\n",
516 if (options.cipher == SSH_CIPHER_3DES)
517 options.ciphers = "3des-cbc";
518 else if (options.cipher == SSH_CIPHER_BLOWFISH)
519 options.ciphers = "blowfish-cbc";
521 options.ciphers = (char *)-1;
525 if (mac_valid(optarg))
526 options.macs = xstrdup(optarg);
528 fprintf(stderr, "Unknown mac type '%s'\n",
534 if (options.control_master == SSHCTL_MASTER_YES)
535 options.control_master = SSHCTL_MASTER_ASK;
537 options.control_master = SSHCTL_MASTER_YES;
540 options.port = a2port(optarg);
541 if (options.port <= 0) {
542 fprintf(stderr, "Bad port '%s'\n", optarg);
547 options.user = optarg;
551 if (parse_forward(&fwd, optarg, 0, 0))
552 add_local_forward(&options, &fwd);
555 "Bad local forwarding specification '%s'\n",
562 if (parse_forward(&fwd, optarg, 0, 1)) {
563 add_remote_forward(&options, &fwd);
566 "Bad remote forwarding specification "
573 if (parse_forward(&fwd, optarg, 1, 0)) {
574 add_local_forward(&options, &fwd);
577 "Bad dynamic forwarding specification "
584 options.compression = 1;
588 options.request_tty = REQUEST_TTY_NO;
591 options.request_tty = REQUEST_TTY_NO;
592 #ifdef NONE_CIPHER_ENABLED
594 * Ensure that the user does not try to backdoor a
595 * NONE cipher switch on an interactive session by
596 * explicitly disabling it if the user asks for a
597 * session without a tty.
599 options.none_switch = 0;
604 line = xstrdup(optarg);
605 if (process_config_line(&options, host ? host : "",
606 line, "command-line", 0, &dummy) != 0)
614 if (options.control_path != NULL)
615 free(options.control_path);
616 options.control_path = xstrdup(optarg);
619 options.bind_address = optarg;
632 if (ac > 0 && !host) {
633 if (strrchr(*av, '@')) {
635 cp = strrchr(p, '@');
636 if (cp == NULL || cp == p)
644 optind = optreset = 1;
650 /* Check that we got a host name. */
654 OpenSSL_add_all_algorithms();
655 ERR_load_crypto_strings();
657 /* Initialize the command to execute on remote host. */
658 buffer_init(&command);
661 * Save the command to execute on the remote host in a buffer. There
662 * is no limit on the length of the command, except by the maximum
663 * packet size. Also sets the tty flag if there is no command.
666 /* No command specified - execute shell on a tty. */
667 if (subsystem_flag) {
669 "You must specify a subsystem to invoke.\n");
673 /* A command has been specified. Store it into the buffer. */
674 for (i = 0; i < ac; i++) {
676 buffer_append(&command, " ", 1);
677 buffer_append(&command, av[i], strlen(av[i]));
681 /* Cannot fork to background if no command. */
682 if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
684 fatal("Cannot fork into background without a command "
688 * Initialize "log" output. Since we are the client all output
689 * actually goes to stderr.
692 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
693 SYSLOG_FACILITY_USER, !use_syslog);
696 * Read per-user configuration file. Ignore the system wide config
697 * file if the user specifies a config file on the command line.
699 if (config != NULL) {
700 if (!read_config_file(config, host, &options, 0))
701 fatal("Can't open user config file %.100s: "
702 "%.100s", config, strerror(errno));
704 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
705 _PATH_SSH_USER_CONFFILE);
706 if (r > 0 && (size_t)r < sizeof(buf))
707 (void)read_config_file(buf, host, &options, 1);
709 /* Read systemwide configuration file after user config. */
710 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
714 /* Fill configuration defaults. */
715 fill_default_options(&options);
717 channel_set_af(options.address_family);
720 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
722 if (options.request_tty == REQUEST_TTY_YES ||
723 options.request_tty == REQUEST_TTY_FORCE)
726 /* Allocate a tty by default if no command specified. */
727 if (buffer_len(&command) == 0)
728 tty_flag = options.request_tty != REQUEST_TTY_NO;
731 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
733 /* Do not allocate a tty if stdin is not a tty. */
734 if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
735 options.request_tty != REQUEST_TTY_FORCE) {
737 logit("Pseudo-terminal will not be allocated because "
738 "stdin is not a terminal.");
744 if (options.user == NULL)
745 options.user = xstrdup(pw->pw_name);
747 /* Get default port if port has not been set. */
748 if (options.port == 0) {
749 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
750 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
753 /* preserve host name given on command line for %n expansion */
755 if (options.hostname != NULL) {
756 host = percent_expand(options.hostname,
757 "h", host, (char *)NULL);
760 if (gethostname(thishost, sizeof(thishost)) == -1)
761 fatal("gethostname: %s", strerror(errno));
762 strlcpy(shorthost, thishost, sizeof(shorthost));
763 shorthost[strcspn(thishost, ".")] = '\0';
764 snprintf(portstr, sizeof(portstr), "%d", options.port);
766 if (options.local_command != NULL) {
767 debug3("expanding LocalCommand: %s", options.local_command);
768 cp = options.local_command;
769 options.local_command = percent_expand(cp, "d", pw->pw_dir,
770 "h", host, "l", thishost, "n", host_arg, "r", options.user,
771 "p", portstr, "u", pw->pw_name, "L", shorthost,
773 debug3("expanded LocalCommand: %s", options.local_command);
777 /* Find canonic host name. */
778 if (strchr(host, '.') == 0) {
779 struct addrinfo hints;
780 struct addrinfo *ai = NULL;
782 memset(&hints, 0, sizeof(hints));
783 hints.ai_family = options.address_family;
784 hints.ai_flags = AI_CANONNAME;
785 hints.ai_socktype = SOCK_STREAM;
786 errgai = getaddrinfo(host, NULL, &hints, &ai);
788 if (ai->ai_canonname != NULL)
789 host = xstrdup(ai->ai_canonname);
794 /* force lowercase for hostkey matching */
795 if (options.host_key_alias != NULL) {
796 for (p = options.host_key_alias; *p; p++)
798 *p = (char)tolower(*p);
801 if (options.proxy_command != NULL &&
802 strcmp(options.proxy_command, "none") == 0) {
803 xfree(options.proxy_command);
804 options.proxy_command = NULL;
806 if (options.control_path != NULL &&
807 strcmp(options.control_path, "none") == 0) {
808 xfree(options.control_path);
809 options.control_path = NULL;
812 if (options.control_path != NULL) {
813 cp = tilde_expand_filename(options.control_path,
815 xfree(options.control_path);
816 options.control_path = percent_expand(cp, "h", host,
817 "l", thishost, "n", host_arg, "r", options.user,
818 "p", portstr, "u", pw->pw_name, "L", shorthost,
822 if (muxclient_command != 0 && options.control_path == NULL)
823 fatal("No ControlPath specified for \"-O\" command");
824 if (options.control_path != NULL)
825 muxclient(options.control_path);
827 timeout_ms = options.connection_timeout * 1000;
829 /* Open a connection to the remote host. */
830 if (ssh_connect(host, &hostaddr, options.port,
831 options.address_family, options.connection_attempts, &timeout_ms,
832 options.tcp_keep_alive,
834 options.use_privileged_port,
836 original_effective_uid == 0 && options.use_privileged_port,
838 options.proxy_command) != 0)
842 debug3("timeout: %d ms remain after connect", timeout_ms);
845 * If we successfully made the connection, load the host private key
846 * in case we will need it later for combined rsa-rhosts
847 * authentication. This must be done before releasing extra
848 * privileges, because the file is only readable by root.
849 * If we cannot access the private keys, load the public keys
850 * instead and try to execute the ssh-keysign helper instead.
852 sensitive_data.nkeys = 0;
853 sensitive_data.keys = NULL;
854 sensitive_data.external_keysign = 0;
855 if (options.rhosts_rsa_authentication ||
856 options.hostbased_authentication) {
857 sensitive_data.nkeys = 7;
858 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
860 for (i = 0; i < sensitive_data.nkeys; i++)
861 sensitive_data.keys[i] = NULL;
864 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
865 _PATH_HOST_KEY_FILE, "", NULL, NULL);
866 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
867 _PATH_HOST_DSA_KEY_FILE, "", NULL);
868 #ifdef OPENSSL_HAS_ECC
869 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
870 _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
872 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
873 _PATH_HOST_RSA_KEY_FILE, "", NULL);
874 sensitive_data.keys[4] = key_load_private_type(KEY_DSA,
875 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
876 #ifdef OPENSSL_HAS_ECC
877 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
878 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
880 sensitive_data.keys[6] = key_load_private_type(KEY_RSA,
881 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
884 if (options.hostbased_authentication == 1 &&
885 sensitive_data.keys[0] == NULL &&
886 sensitive_data.keys[4] == NULL &&
887 sensitive_data.keys[5] == NULL &&
888 sensitive_data.keys[6] == NULL) {
889 sensitive_data.keys[1] = key_load_cert(
890 _PATH_HOST_DSA_KEY_FILE);
891 #ifdef OPENSSL_HAS_ECC
892 sensitive_data.keys[2] = key_load_cert(
893 _PATH_HOST_ECDSA_KEY_FILE);
895 sensitive_data.keys[3] = key_load_cert(
896 _PATH_HOST_RSA_KEY_FILE);
897 sensitive_data.keys[4] = key_load_public(
898 _PATH_HOST_DSA_KEY_FILE, NULL);
899 #ifdef OPENSSL_HAS_ECC
900 sensitive_data.keys[5] = key_load_public(
901 _PATH_HOST_ECDSA_KEY_FILE, NULL);
903 sensitive_data.keys[6] = key_load_public(
904 _PATH_HOST_RSA_KEY_FILE, NULL);
905 sensitive_data.external_keysign = 1;
909 * Get rid of any extra privileges that we may have. We will no
910 * longer need them. Also, extra privileges could make it very hard
911 * to read identity files and other non-world-readable files from the
912 * user's home directory if it happens to be on a NFS volume where
913 * root is mapped to nobody.
915 if (original_effective_uid == 0) {
917 permanently_set_uid(pw);
921 * Now that we are back to our own permissions, create ~/.ssh
922 * directory if it doesn't already exist.
924 if (config == NULL) {
925 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
926 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
927 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
929 ssh_selinux_setfscreatecon(buf);
931 if (mkdir(buf, 0700) < 0)
932 error("Could not create directory '%.200s'.",
935 ssh_selinux_setfscreatecon(NULL);
939 /* load options.identity_files */
940 load_public_identity_files();
942 /* Expand ~ in known host file names. */
943 tilde_expand_paths(options.system_hostfiles,
944 options.num_system_hostfiles);
945 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
947 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
948 signal(SIGCHLD, main_sigchld_handler);
950 /* Log into the remote system. Never returns if the login fails. */
951 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
952 options.port, pw, timeout_ms);
954 if (packet_connection_is_on_socket()) {
955 verbose("Authenticated to %s ([%s]:%d).", host,
956 get_remote_ipaddr(), get_remote_port());
958 verbose("Authenticated to %s (via proxy).", host);
961 /* We no longer need the private host keys. Clear them now. */
962 if (sensitive_data.nkeys != 0) {
963 for (i = 0; i < sensitive_data.nkeys; i++) {
964 if (sensitive_data.keys[i] != NULL) {
965 /* Destroys contents safely */
966 debug3("clear hostkey %d", i);
967 key_free(sensitive_data.keys[i]);
968 sensitive_data.keys[i] = NULL;
971 xfree(sensitive_data.keys);
973 for (i = 0; i < options.num_identity_files; i++) {
974 if (options.identity_files[i]) {
975 xfree(options.identity_files[i]);
976 options.identity_files[i] = NULL;
978 if (options.identity_keys[i]) {
979 key_free(options.identity_keys[i]);
980 options.identity_keys[i] = NULL;
984 exit_status = compat20 ? ssh_session2() : ssh_session();
987 if (options.control_path != NULL && muxserver_sock != -1)
988 unlink(options.control_path);
990 /* Kill ProxyCommand if it is running. */
991 ssh_kill_proxy_command();
997 control_persist_detach(void)
1002 debug("%s: backgrounding master process", __func__);
1005 * master (current process) into the background, and make the
1006 * foreground process a client of the backgrounded master.
1008 switch ((pid = fork())) {
1010 fatal("%s: fork: %s", __func__, strerror(errno));
1012 /* Child: master process continues mainloop */
1015 /* Parent: set up mux slave to connect to backgrounded master */
1016 debug2("%s: background process is %ld", __func__, (long)pid);
1017 stdin_null_flag = ostdin_null_flag;
1018 options.request_tty = orequest_tty;
1019 tty_flag = otty_flag;
1020 close(muxserver_sock);
1021 muxserver_sock = -1;
1022 options.control_master = SSHCTL_MASTER_NO;
1023 muxclient(options.control_path);
1024 /* muxclient() doesn't return on success. */
1025 fatal("Failed to connect to new control master");
1027 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1028 error("%s: open(\"/dev/null\"): %s", __func__,
1031 if (dup2(devnull, STDIN_FILENO) == -1 ||
1032 dup2(devnull, STDOUT_FILENO) == -1)
1033 error("%s: dup2: %s", __func__, strerror(errno));
1034 if (devnull > STDERR_FILENO)
1037 setproctitle("%s [mux]", options.control_path);
1040 /* Do fork() after authentication. Used by "ssh -f" */
1044 if (need_controlpersist_detach)
1045 control_persist_detach();
1046 debug("forking to background");
1047 fork_after_authentication_flag = 0;
1048 if (daemon(1, 1) < 0)
1049 fatal("daemon() failed: %.200s", strerror(errno));
1052 /* Callback for remote forward global requests */
1054 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1056 Forward *rfwd = (Forward *)ctxt;
1058 /* XXX verbose() on failure? */
1059 debug("remote forward %s for: listen %d, connect %s:%d",
1060 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1061 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
1062 if (rfwd->listen_port == 0) {
1063 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1064 rfwd->allocated_port = packet_get_int();
1065 logit("Allocated port %u for remote forward to %s:%d",
1066 rfwd->allocated_port,
1067 rfwd->connect_host, rfwd->connect_port);
1068 channel_update_permitted_opens(rfwd->handle,
1069 rfwd->allocated_port);
1071 channel_update_permitted_opens(rfwd->handle, -1);
1075 if (type == SSH2_MSG_REQUEST_FAILURE) {
1076 if (options.exit_on_forward_failure)
1077 fatal("Error: remote port forwarding failed for "
1078 "listen port %d", rfwd->listen_port);
1080 logit("Warning: remote port forwarding failed for "
1081 "listen port %d", rfwd->listen_port);
1083 if (++remote_forward_confirms_received == options.num_remote_forwards) {
1084 debug("All remote forwarding requests processed");
1085 if (fork_after_authentication_flag)
1091 client_cleanup_stdio_fwd(int id, void *arg)
1093 debug("stdio forwarding: done");
1098 ssh_init_stdio_forwarding(void)
1103 if (stdio_forward_host == NULL)
1106 fatal("stdio forwarding require Protocol 2");
1108 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1110 if ((in = dup(STDIN_FILENO)) < 0 ||
1111 (out = dup(STDOUT_FILENO)) < 0)
1112 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1113 if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1114 stdio_forward_port, in, out)) == NULL)
1115 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1116 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1120 ssh_init_forwarding(void)
1125 /* Initiate local TCP/IP port forwardings. */
1126 for (i = 0; i < options.num_local_forwards; i++) {
1127 debug("Local connections to %.200s:%d forwarded to remote "
1128 "address %.200s:%d",
1129 (options.local_forwards[i].listen_host == NULL) ?
1130 (options.gateway_ports ? "*" : "LOCALHOST") :
1131 options.local_forwards[i].listen_host,
1132 options.local_forwards[i].listen_port,
1133 options.local_forwards[i].connect_host,
1134 options.local_forwards[i].connect_port);
1135 success += channel_setup_local_fwd_listener(
1136 options.local_forwards[i].listen_host,
1137 options.local_forwards[i].listen_port,
1138 options.local_forwards[i].connect_host,
1139 options.local_forwards[i].connect_port,
1140 options.gateway_ports);
1142 if (i > 0 && success != i && options.exit_on_forward_failure)
1143 fatal("Could not request local forwarding.");
1144 if (i > 0 && success == 0)
1145 error("Could not request local forwarding.");
1147 /* Initiate remote TCP/IP port forwardings. */
1148 for (i = 0; i < options.num_remote_forwards; i++) {
1149 debug("Remote connections from %.200s:%d forwarded to "
1150 "local address %.200s:%d",
1151 (options.remote_forwards[i].listen_host == NULL) ?
1152 "LOCALHOST" : options.remote_forwards[i].listen_host,
1153 options.remote_forwards[i].listen_port,
1154 options.remote_forwards[i].connect_host,
1155 options.remote_forwards[i].connect_port);
1156 options.remote_forwards[i].handle =
1157 channel_request_remote_forwarding(
1158 options.remote_forwards[i].listen_host,
1159 options.remote_forwards[i].listen_port,
1160 options.remote_forwards[i].connect_host,
1161 options.remote_forwards[i].connect_port);
1162 if (options.remote_forwards[i].handle < 0) {
1163 if (options.exit_on_forward_failure)
1164 fatal("Could not request remote forwarding.");
1166 logit("Warning: Could not request remote "
1169 client_register_global_confirm(ssh_confirm_remote_forward,
1170 &options.remote_forwards[i]);
1174 /* Initiate tunnel forwarding. */
1175 if (options.tun_open != SSH_TUNMODE_NO) {
1176 if (client_request_tun_fwd(options.tun_open,
1177 options.tun_local, options.tun_remote) == -1) {
1178 if (options.exit_on_forward_failure)
1179 fatal("Could not request tunnel forwarding.");
1181 error("Could not request tunnel forwarding.");
1187 check_agent_present(void)
1189 if (options.forward_agent) {
1190 /* Clear agent forwarding if we don't have an agent. */
1191 if (!ssh_agent_present())
1192 options.forward_agent = 0;
1200 int interactive = 0;
1204 const char *display;
1206 /* Enable compression if requested. */
1207 if (options.compression) {
1208 debug("Requesting compression at level %d.",
1209 options.compression_level);
1211 if (options.compression_level < 1 ||
1212 options.compression_level > 9)
1213 fatal("Compression level must be from 1 (fast) to "
1216 /* Send the request. */
1217 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1218 packet_put_int(options.compression_level);
1220 packet_write_wait();
1221 type = packet_read();
1222 if (type == SSH_SMSG_SUCCESS)
1223 packet_start_compression(options.compression_level);
1224 else if (type == SSH_SMSG_FAILURE)
1225 logit("Warning: Remote host refused compression.");
1227 packet_disconnect("Protocol error waiting for "
1228 "compression response.");
1230 /* Allocate a pseudo tty if appropriate. */
1232 debug("Requesting pty.");
1234 /* Start the packet. */
1235 packet_start(SSH_CMSG_REQUEST_PTY);
1237 /* Store TERM in the packet. There is no limit on the
1238 length of the string. */
1239 cp = getenv("TERM");
1242 packet_put_cstring(cp);
1244 /* Store window size in the packet. */
1245 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1246 memset(&ws, 0, sizeof(ws));
1247 packet_put_int((u_int)ws.ws_row);
1248 packet_put_int((u_int)ws.ws_col);
1249 packet_put_int((u_int)ws.ws_xpixel);
1250 packet_put_int((u_int)ws.ws_ypixel);
1252 /* Store tty modes in the packet. */
1253 tty_make_modes(fileno(stdin), NULL);
1255 /* Send the packet, and wait for it to leave. */
1257 packet_write_wait();
1259 /* Read response from the server. */
1260 type = packet_read();
1261 if (type == SSH_SMSG_SUCCESS) {
1264 } else if (type == SSH_SMSG_FAILURE)
1265 logit("Warning: Remote host failed or refused to "
1266 "allocate a pseudo tty.");
1268 packet_disconnect("Protocol error waiting for pty "
1269 "request response.");
1271 /* Request X11 forwarding if enabled and DISPLAY is set. */
1272 display = getenv("DISPLAY");
1273 if (options.forward_x11 && display != NULL) {
1275 /* Get reasonable local authentication information. */
1276 client_x11_get_proto(display, options.xauth_location,
1277 options.forward_x11_trusted,
1278 options.forward_x11_timeout,
1280 /* Request forwarding with authentication spoofing. */
1281 debug("Requesting X11 forwarding with authentication "
1283 x11_request_forwarding_with_spoofing(0, display, proto,
1285 /* Read response from the server. */
1286 type = packet_read();
1287 if (type == SSH_SMSG_SUCCESS) {
1289 } else if (type == SSH_SMSG_FAILURE) {
1290 logit("Warning: Remote host denied X11 forwarding.");
1292 packet_disconnect("Protocol error waiting for X11 "
1296 /* Tell the packet module whether this is an interactive session. */
1297 packet_set_interactive(interactive,
1298 options.ip_qos_interactive, options.ip_qos_bulk);
1300 /* Request authentication agent forwarding if appropriate. */
1301 check_agent_present();
1303 if (options.forward_agent) {
1304 debug("Requesting authentication agent forwarding.");
1305 auth_request_forwarding();
1307 /* Read response from the server. */
1308 type = packet_read();
1310 if (type != SSH_SMSG_SUCCESS)
1311 logit("Warning: Remote host denied authentication agent forwarding.");
1314 /* Initiate port forwardings. */
1315 ssh_init_stdio_forwarding();
1316 ssh_init_forwarding();
1318 /* Execute a local command */
1319 if (options.local_command != NULL &&
1320 options.permit_local_command)
1321 ssh_local_cmd(options.local_command);
1324 * If requested and we are not interested in replies to remote
1325 * forwarding requests, then let ssh continue in the background.
1327 if (fork_after_authentication_flag) {
1328 if (options.exit_on_forward_failure &&
1329 options.num_remote_forwards > 0) {
1330 debug("deferring postauth fork until remote forward "
1331 "confirmation received");
1337 * If a command was specified on the command line, execute the
1338 * command now. Otherwise request the server to start a shell.
1340 if (buffer_len(&command) > 0) {
1341 int len = buffer_len(&command);
1344 debug("Sending command: %.*s", len,
1345 (u_char *)buffer_ptr(&command));
1346 packet_start(SSH_CMSG_EXEC_CMD);
1347 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1349 packet_write_wait();
1351 debug("Requesting shell.");
1352 packet_start(SSH_CMSG_EXEC_SHELL);
1354 packet_write_wait();
1357 /* Enter the interactive session. */
1358 return client_loop(have_tty, tty_flag ?
1359 options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1362 /* request pty/x11/agent/tcpfwd/shell for channel */
1364 ssh_session2_setup(int id, int success, void *arg)
1366 extern char **environ;
1367 const char *display;
1368 int interactive = tty_flag;
1371 return; /* No need for error message, channels code sens one */
1373 display = getenv("DISPLAY");
1374 if (options.forward_x11 && display != NULL) {
1376 /* Get reasonable local authentication information. */
1377 client_x11_get_proto(display, options.xauth_location,
1378 options.forward_x11_trusted,
1379 options.forward_x11_timeout, &proto, &data);
1380 /* Request forwarding with authentication spoofing. */
1381 debug("Requesting X11 forwarding with authentication "
1383 x11_request_forwarding_with_spoofing(id, display, proto,
1385 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1386 /* XXX exit_on_forward_failure */
1390 check_agent_present();
1391 if (options.forward_agent) {
1392 debug("Requesting authentication agent forwarding.");
1393 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1397 /* Tell the packet module whether this is an interactive session. */
1398 packet_set_interactive(interactive,
1399 options.ip_qos_interactive, options.ip_qos_bulk);
1401 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1402 NULL, fileno(stdin), &command, environ);
1405 /* open new channel for a session */
1407 ssh_session2_open(void)
1410 int window, packetmax, in, out, err;
1412 if (stdin_null_flag) {
1413 in = open(_PATH_DEVNULL, O_RDONLY);
1415 in = dup(STDIN_FILENO);
1417 out = dup(STDOUT_FILENO);
1418 err = dup(STDERR_FILENO);
1420 if (in < 0 || out < 0 || err < 0)
1421 fatal("dup() in/out/err failed");
1423 /* enable nonblocking unless tty */
1432 * We need to check to see what to do about buffer sizes here.
1433 * - In an HPN to non-HPN connection we want to limit the window size to
1434 * something reasonable in case the far side has the large window bug.
1435 * - In an HPN to HPN connection we want to use the max window size but
1436 * allow the user to override it.
1437 * - Lastly if HPN is disabled then use the ssh standard window size.
1439 * We cannot just do a getsockopt() here and set the ssh window to that
1440 * as in case of autotuning of socket buffers the window would get stuck
1441 * at the initial buffer size, generally less than 96k. Therefore we
1442 * need to set the maximum ssh window size to the maximum HPN buffer
1443 * size unless the user has set TcpRcvBufPoll to no. In that case we
1444 * can just set the window to the minimum of HPN buffer size and TCP
1445 * receive buffer size.
1448 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1450 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT;
1452 if (datafellows & SSH_BUG_LARGEWINDOW) {
1453 debug("HPN to Non-HPN Connection");
1454 } else if (options.tcp_rcv_buf_poll <= 0) {
1455 sock_get_rcvbuf(&options.hpn_buffer_size, 0);
1456 debug("HPNBufferSize set to TCP RWIN: %d",
1457 options.hpn_buffer_size);
1458 } else if (options.tcp_rcv_buf > 0) {
1459 sock_get_rcvbuf(&options.hpn_buffer_size,
1460 options.tcp_rcv_buf);
1461 debug("HPNBufferSize set to user TCPRcvBuf: %d",
1462 options.hpn_buffer_size);
1464 debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1465 channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1466 window = options.hpn_buffer_size;
1468 packetmax = CHAN_SES_PACKET_DEFAULT;
1470 window = CHAN_SES_WINDOW_DEFAULT;
1475 "session", SSH_CHANNEL_OPENING, in, out, err,
1476 window, packetmax, CHAN_EXTENDED_WRITE,
1477 "client-session", /*nonblock*/0);
1478 if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) {
1479 c->dynamic_window = 1;
1480 debug("Enabled Dynamic Window Scaling\n");
1483 debug3("ssh_session2_open: channel_new: %d", c->self);
1485 channel_send_open(c->self);
1487 channel_register_open_confirm(c->self,
1488 ssh_session2_setup, NULL);
1498 /* XXX should be pre-session */
1499 if (!options.control_persist)
1500 ssh_init_stdio_forwarding();
1501 ssh_init_forwarding();
1503 /* Start listening for multiplex clients */
1507 * If we are in control persist mode and have a working mux listen
1508 * socket, then prepare to background ourselves and have a foreground
1509 * client attach as a control slave.
1510 * NB. we must save copies of the flags that we override for
1511 * the backgrounding, since we defer attachment of the slave until
1512 * after the connection is fully established (in particular,
1513 * async rfwd replies have been received for ExitOnForwardFailure).
1515 if (options.control_persist && muxserver_sock != -1) {
1516 ostdin_null_flag = stdin_null_flag;
1517 ono_shell_flag = no_shell_flag;
1518 orequest_tty = options.request_tty;
1519 otty_flag = tty_flag;
1520 stdin_null_flag = 1;
1523 if (!fork_after_authentication_flag)
1524 need_controlpersist_detach = 1;
1525 fork_after_authentication_flag = 1;
1528 * ControlPersist mux listen socket setup failed, attempt the
1529 * stdio forward setup that we skipped earlier.
1531 if (options.control_persist && muxserver_sock == -1)
1532 ssh_init_stdio_forwarding();
1534 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1535 id = ssh_session2_open();
1537 /* If we don't expect to open a new session, then disallow it */
1538 if (options.control_master == SSHCTL_MASTER_NO &&
1539 (datafellows & SSH_NEW_OPENSSH)) {
1540 debug("Requesting no-more-sessions@openssh.com");
1541 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1542 packet_put_cstring("no-more-sessions@openssh.com");
1547 /* Execute a local command */
1548 if (options.local_command != NULL &&
1549 options.permit_local_command)
1550 ssh_local_cmd(options.local_command);
1553 * If requested and we are not interested in replies to remote
1554 * forwarding requests, then let ssh continue in the background.
1556 if (fork_after_authentication_flag) {
1557 if (options.exit_on_forward_failure &&
1558 options.num_remote_forwards > 0) {
1559 debug("deferring postauth fork until remote forward "
1560 "confirmation received");
1565 if (options.use_roaming)
1568 return client_loop(tty_flag, tty_flag ?
1569 options.escape_char : SSH_ESCAPECHAR_NONE, id);
1573 load_public_identity_files(void)
1575 char *filename, *cp, thishost[NI_MAXHOST];
1576 char *pwdir = NULL, *pwname = NULL;
1581 char *identity_files[SSH_MAX_IDENTITY_FILES];
1582 Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1583 #ifdef ENABLE_PKCS11
1589 bzero(identity_files, sizeof(identity_files));
1590 bzero(identity_keys, sizeof(identity_keys));
1592 #ifdef ENABLE_PKCS11
1593 if (options.pkcs11_provider != NULL &&
1594 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1595 (pkcs11_init(!options.batch_mode) == 0) &&
1596 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1598 for (i = 0; i < nkeys; i++) {
1599 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1603 identity_keys[n_ids] = keys[i];
1604 identity_files[n_ids] =
1605 xstrdup(options.pkcs11_provider); /* XXX */
1610 #endif /* ENABLE_PKCS11 */
1611 if ((pw = getpwuid(original_real_uid)) == NULL)
1612 fatal("load_public_identity_files: getpwuid failed");
1613 pwname = xstrdup(pw->pw_name);
1614 pwdir = xstrdup(pw->pw_dir);
1615 if (gethostname(thishost, sizeof(thishost)) == -1)
1616 fatal("load_public_identity_files: gethostname: %s",
1618 for (i = 0; i < options.num_identity_files; i++) {
1619 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1620 xfree(options.identity_files[i]);
1623 cp = tilde_expand_filename(options.identity_files[i],
1625 filename = percent_expand(cp, "d", pwdir,
1626 "u", pwname, "l", thishost, "h", host,
1627 "r", options.user, (char *)NULL);
1629 public = key_load_public(filename, NULL);
1630 debug("identity file %s type %d", filename,
1631 public ? public->type : -1);
1632 xfree(options.identity_files[i]);
1633 identity_files[n_ids] = filename;
1634 identity_keys[n_ids] = public;
1636 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1639 /* Try to add the certificate variant too */
1640 xasprintf(&cp, "%s-cert", filename);
1641 public = key_load_public(cp, NULL);
1642 debug("identity file %s type %d", cp,
1643 public ? public->type : -1);
1644 if (public == NULL) {
1648 if (!key_is_cert(public)) {
1649 debug("%s: key %s type %s is not a certificate",
1650 __func__, cp, key_type(public));
1655 identity_keys[n_ids] = public;
1656 /* point to the original path, most likely the private key */
1657 identity_files[n_ids] = xstrdup(filename);
1660 options.num_identity_files = n_ids;
1661 memcpy(options.identity_files, identity_files, sizeof(identity_files));
1662 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1664 bzero(pwname, strlen(pwname));
1666 bzero(pwdir, strlen(pwdir));
1671 main_sigchld_handler(int sig)
1673 int save_errno = errno;
1677 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1678 (pid < 0 && errno == EINTR))
1681 signal(sig, main_sigchld_handler);