1 /* $OpenBSD: ssh.c,v 1.373 2013/02/22 22:09:01 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 add_identity_file(&options, NULL, optarg, 1);
414 options.pkcs11_provider = xstrdup(optarg);
416 fprintf(stderr, "no support for PKCS#11.\n");
420 if (options.request_tty == REQUEST_TTY_YES)
421 options.request_tty = REQUEST_TTY_FORCE;
423 options.request_tty = REQUEST_TTY_YES;
426 if (debug_flag == 0) {
428 options.log_level = SYSLOG_LEVEL_DEBUG1;
430 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
436 if (options.version_addendum &&
437 *options.version_addendum != '\0')
438 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
439 options.hpn_disabled ? "" : SSH_VERSION_HPN,
440 options.version_addendum,
441 SSLeay_version(SSLEAY_VERSION));
443 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE,
444 options.hpn_disabled ? "" : SSH_VERSION_HPN,
445 SSLeay_version(SSLEAY_VERSION));
450 if (options.tun_open == -1)
451 options.tun_open = SSH_TUNMODE_DEFAULT;
452 options.tun_local = a2tun(optarg, &options.tun_remote);
453 if (options.tun_local == SSH_TUNID_ERR) {
455 "Bad tun device '%s'\n", optarg);
460 if (stdio_forward_host != NULL)
461 fatal("stdio forward already specified");
462 if (muxclient_command != 0)
463 fatal("Cannot specify stdio forward with -O");
464 if (parse_forward(&fwd, optarg, 1, 0)) {
465 stdio_forward_host = fwd.listen_host;
466 stdio_forward_port = fwd.listen_port;
467 xfree(fwd.connect_host);
470 "Bad stdio forwarding specification '%s'\n",
474 options.request_tty = REQUEST_TTY_NO;
476 options.clear_forwardings = 1;
477 options.exit_on_forward_failure = 1;
480 options.log_level = SYSLOG_LEVEL_QUIET;
483 if (optarg[0] == '^' && optarg[2] == 0 &&
484 (u_char) optarg[1] >= 64 &&
485 (u_char) optarg[1] < 128)
486 options.escape_char = (u_char) optarg[1] & 31;
487 else if (strlen(optarg) == 1)
488 options.escape_char = (u_char) optarg[0];
489 else if (strcmp(optarg, "none") == 0)
490 options.escape_char = SSH_ESCAPECHAR_NONE;
492 fprintf(stderr, "Bad escape character '%s'.\n",
498 if (ciphers_valid(optarg)) {
500 options.ciphers = xstrdup(optarg);
501 options.cipher = SSH_CIPHER_INVALID;
504 options.cipher = cipher_number(optarg);
505 if (options.cipher == -1) {
507 "Unknown cipher type '%s'\n",
511 if (options.cipher == SSH_CIPHER_3DES)
512 options.ciphers = "3des-cbc";
513 else if (options.cipher == SSH_CIPHER_BLOWFISH)
514 options.ciphers = "blowfish-cbc";
516 options.ciphers = (char *)-1;
520 if (mac_valid(optarg))
521 options.macs = xstrdup(optarg);
523 fprintf(stderr, "Unknown mac type '%s'\n",
529 if (options.control_master == SSHCTL_MASTER_YES)
530 options.control_master = SSHCTL_MASTER_ASK;
532 options.control_master = SSHCTL_MASTER_YES;
535 options.port = a2port(optarg);
536 if (options.port <= 0) {
537 fprintf(stderr, "Bad port '%s'\n", optarg);
542 options.user = optarg;
546 if (parse_forward(&fwd, optarg, 0, 0))
547 add_local_forward(&options, &fwd);
550 "Bad local forwarding specification '%s'\n",
557 if (parse_forward(&fwd, optarg, 0, 1)) {
558 add_remote_forward(&options, &fwd);
561 "Bad remote forwarding specification "
568 if (parse_forward(&fwd, optarg, 1, 0)) {
569 add_local_forward(&options, &fwd);
572 "Bad dynamic forwarding specification "
579 options.compression = 1;
583 options.request_tty = REQUEST_TTY_NO;
586 options.request_tty = REQUEST_TTY_NO;
587 #ifdef NONE_CIPHER_ENABLED
589 * Ensure that the user does not try to backdoor a
590 * NONE cipher switch on an interactive session by
591 * explicitly disabling it if the user asks for a
592 * session without a tty.
594 options.none_switch = 0;
599 line = xstrdup(optarg);
600 if (process_config_line(&options, host ? host : "",
601 line, "command-line", 0, &dummy, SSHCONF_USERCONF)
610 if (options.control_path != NULL)
611 free(options.control_path);
612 options.control_path = xstrdup(optarg);
615 options.bind_address = optarg;
628 if (ac > 0 && !host) {
629 if (strrchr(*av, '@')) {
631 cp = strrchr(p, '@');
632 if (cp == NULL || cp == p)
640 optind = optreset = 1;
646 /* Check that we got a host name. */
650 OpenSSL_add_all_algorithms();
651 ERR_load_crypto_strings();
653 /* Initialize the command to execute on remote host. */
654 buffer_init(&command);
657 * Save the command to execute on the remote host in a buffer. There
658 * is no limit on the length of the command, except by the maximum
659 * packet size. Also sets the tty flag if there is no command.
662 /* No command specified - execute shell on a tty. */
663 if (subsystem_flag) {
665 "You must specify a subsystem to invoke.\n");
669 /* A command has been specified. Store it into the buffer. */
670 for (i = 0; i < ac; i++) {
672 buffer_append(&command, " ", 1);
673 buffer_append(&command, av[i], strlen(av[i]));
677 /* Cannot fork to background if no command. */
678 if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
680 fatal("Cannot fork into background without a command "
684 * Initialize "log" output. Since we are the client all output
685 * actually goes to stderr.
688 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
689 SYSLOG_FACILITY_USER, !use_syslog);
692 * Read per-user configuration file. Ignore the system wide config
693 * file if the user specifies a config file on the command line.
695 if (config != NULL) {
696 if (!read_config_file(config, host, &options, SSHCONF_USERCONF))
697 fatal("Can't open user config file %.100s: "
698 "%.100s", config, strerror(errno));
700 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
701 _PATH_SSH_USER_CONFFILE);
702 if (r > 0 && (size_t)r < sizeof(buf))
703 (void)read_config_file(buf, host, &options,
704 SSHCONF_CHECKPERM|SSHCONF_USERCONF);
706 /* Read systemwide configuration file after user config. */
707 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
711 /* Fill configuration defaults. */
712 fill_default_options(&options);
714 channel_set_af(options.address_family);
717 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
719 if (options.request_tty == REQUEST_TTY_YES ||
720 options.request_tty == REQUEST_TTY_FORCE)
723 /* Allocate a tty by default if no command specified. */
724 if (buffer_len(&command) == 0)
725 tty_flag = options.request_tty != REQUEST_TTY_NO;
728 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
730 /* Do not allocate a tty if stdin is not a tty. */
731 if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
732 options.request_tty != REQUEST_TTY_FORCE) {
734 logit("Pseudo-terminal will not be allocated because "
735 "stdin is not a terminal.");
741 if (options.user == NULL)
742 options.user = xstrdup(pw->pw_name);
744 /* Get default port if port has not been set. */
745 if (options.port == 0) {
746 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
747 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
750 /* preserve host name given on command line for %n expansion */
752 if (options.hostname != NULL) {
753 host = percent_expand(options.hostname,
754 "h", host, (char *)NULL);
757 if (gethostname(thishost, sizeof(thishost)) == -1)
758 fatal("gethostname: %s", strerror(errno));
759 strlcpy(shorthost, thishost, sizeof(shorthost));
760 shorthost[strcspn(thishost, ".")] = '\0';
761 snprintf(portstr, sizeof(portstr), "%d", options.port);
763 if (options.local_command != NULL) {
764 debug3("expanding LocalCommand: %s", options.local_command);
765 cp = options.local_command;
766 options.local_command = percent_expand(cp, "d", pw->pw_dir,
767 "h", host, "l", thishost, "n", host_arg, "r", options.user,
768 "p", portstr, "u", pw->pw_name, "L", shorthost,
770 debug3("expanded LocalCommand: %s", options.local_command);
774 /* Find canonic host name. */
775 if (strchr(host, '.') == 0) {
776 struct addrinfo hints;
777 struct addrinfo *ai = NULL;
779 memset(&hints, 0, sizeof(hints));
780 hints.ai_family = options.address_family;
781 hints.ai_flags = AI_CANONNAME;
782 hints.ai_socktype = SOCK_STREAM;
783 errgai = getaddrinfo(host, NULL, &hints, &ai);
785 if (ai->ai_canonname != NULL)
786 host = xstrdup(ai->ai_canonname);
791 /* force lowercase for hostkey matching */
792 if (options.host_key_alias != NULL) {
793 for (p = options.host_key_alias; *p; p++)
795 *p = (char)tolower(*p);
798 if (options.proxy_command != NULL &&
799 strcmp(options.proxy_command, "none") == 0) {
800 xfree(options.proxy_command);
801 options.proxy_command = NULL;
803 if (options.control_path != NULL &&
804 strcmp(options.control_path, "none") == 0) {
805 xfree(options.control_path);
806 options.control_path = NULL;
809 if (options.control_path != NULL) {
810 cp = tilde_expand_filename(options.control_path,
812 xfree(options.control_path);
813 options.control_path = percent_expand(cp, "h", host,
814 "l", thishost, "n", host_arg, "r", options.user,
815 "p", portstr, "u", pw->pw_name, "L", shorthost,
819 if (muxclient_command != 0 && options.control_path == NULL)
820 fatal("No ControlPath specified for \"-O\" command");
821 if (options.control_path != NULL)
822 muxclient(options.control_path);
824 timeout_ms = options.connection_timeout * 1000;
826 /* Open a connection to the remote host. */
827 if (ssh_connect(host, &hostaddr, options.port,
828 options.address_family, options.connection_attempts, &timeout_ms,
829 options.tcp_keep_alive,
831 options.use_privileged_port,
833 original_effective_uid == 0 && options.use_privileged_port,
835 options.proxy_command) != 0)
839 debug3("timeout: %d ms remain after connect", timeout_ms);
842 * If we successfully made the connection, load the host private key
843 * in case we will need it later for combined rsa-rhosts
844 * authentication. This must be done before releasing extra
845 * privileges, because the file is only readable by root.
846 * If we cannot access the private keys, load the public keys
847 * instead and try to execute the ssh-keysign helper instead.
849 sensitive_data.nkeys = 0;
850 sensitive_data.keys = NULL;
851 sensitive_data.external_keysign = 0;
852 if (options.rhosts_rsa_authentication ||
853 options.hostbased_authentication) {
854 sensitive_data.nkeys = 7;
855 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
857 for (i = 0; i < sensitive_data.nkeys; i++)
858 sensitive_data.keys[i] = NULL;
861 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
862 _PATH_HOST_KEY_FILE, "", NULL, NULL);
863 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
864 _PATH_HOST_DSA_KEY_FILE, "", NULL);
865 #ifdef OPENSSL_HAS_ECC
866 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
867 _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
869 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
870 _PATH_HOST_RSA_KEY_FILE, "", NULL);
871 sensitive_data.keys[4] = key_load_private_type(KEY_DSA,
872 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
873 #ifdef OPENSSL_HAS_ECC
874 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
875 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
877 sensitive_data.keys[6] = key_load_private_type(KEY_RSA,
878 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
881 if (options.hostbased_authentication == 1 &&
882 sensitive_data.keys[0] == NULL &&
883 sensitive_data.keys[4] == NULL &&
884 sensitive_data.keys[5] == NULL &&
885 sensitive_data.keys[6] == NULL) {
886 sensitive_data.keys[1] = key_load_cert(
887 _PATH_HOST_DSA_KEY_FILE);
888 #ifdef OPENSSL_HAS_ECC
889 sensitive_data.keys[2] = key_load_cert(
890 _PATH_HOST_ECDSA_KEY_FILE);
892 sensitive_data.keys[3] = key_load_cert(
893 _PATH_HOST_RSA_KEY_FILE);
894 sensitive_data.keys[4] = key_load_public(
895 _PATH_HOST_DSA_KEY_FILE, NULL);
896 #ifdef OPENSSL_HAS_ECC
897 sensitive_data.keys[5] = key_load_public(
898 _PATH_HOST_ECDSA_KEY_FILE, NULL);
900 sensitive_data.keys[6] = key_load_public(
901 _PATH_HOST_RSA_KEY_FILE, NULL);
902 sensitive_data.external_keysign = 1;
906 * Get rid of any extra privileges that we may have. We will no
907 * longer need them. Also, extra privileges could make it very hard
908 * to read identity files and other non-world-readable files from the
909 * user's home directory if it happens to be on a NFS volume where
910 * root is mapped to nobody.
912 if (original_effective_uid == 0) {
914 permanently_set_uid(pw);
918 * Now that we are back to our own permissions, create ~/.ssh
919 * directory if it doesn't already exist.
921 if (config == NULL) {
922 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
923 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
924 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
926 ssh_selinux_setfscreatecon(buf);
928 if (mkdir(buf, 0700) < 0)
929 error("Could not create directory '%.200s'.",
932 ssh_selinux_setfscreatecon(NULL);
936 /* load options.identity_files */
937 load_public_identity_files();
939 /* Expand ~ in known host file names. */
940 tilde_expand_paths(options.system_hostfiles,
941 options.num_system_hostfiles);
942 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
944 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
945 signal(SIGCHLD, main_sigchld_handler);
947 /* Log into the remote system. Never returns if the login fails. */
948 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
949 options.port, pw, timeout_ms);
951 if (packet_connection_is_on_socket()) {
952 verbose("Authenticated to %s ([%s]:%d).", host,
953 get_remote_ipaddr(), get_remote_port());
955 verbose("Authenticated to %s (via proxy).", host);
958 /* We no longer need the private host keys. Clear them now. */
959 if (sensitive_data.nkeys != 0) {
960 for (i = 0; i < sensitive_data.nkeys; i++) {
961 if (sensitive_data.keys[i] != NULL) {
962 /* Destroys contents safely */
963 debug3("clear hostkey %d", i);
964 key_free(sensitive_data.keys[i]);
965 sensitive_data.keys[i] = NULL;
968 xfree(sensitive_data.keys);
970 for (i = 0; i < options.num_identity_files; i++) {
971 if (options.identity_files[i]) {
972 xfree(options.identity_files[i]);
973 options.identity_files[i] = NULL;
975 if (options.identity_keys[i]) {
976 key_free(options.identity_keys[i]);
977 options.identity_keys[i] = NULL;
981 exit_status = compat20 ? ssh_session2() : ssh_session();
984 if (options.control_path != NULL && muxserver_sock != -1)
985 unlink(options.control_path);
987 /* Kill ProxyCommand if it is running. */
988 ssh_kill_proxy_command();
994 control_persist_detach(void)
999 debug("%s: backgrounding master process", __func__);
1002 * master (current process) into the background, and make the
1003 * foreground process a client of the backgrounded master.
1005 switch ((pid = fork())) {
1007 fatal("%s: fork: %s", __func__, strerror(errno));
1009 /* Child: master process continues mainloop */
1012 /* Parent: set up mux slave to connect to backgrounded master */
1013 debug2("%s: background process is %ld", __func__, (long)pid);
1014 stdin_null_flag = ostdin_null_flag;
1015 options.request_tty = orequest_tty;
1016 tty_flag = otty_flag;
1017 close(muxserver_sock);
1018 muxserver_sock = -1;
1019 options.control_master = SSHCTL_MASTER_NO;
1020 muxclient(options.control_path);
1021 /* muxclient() doesn't return on success. */
1022 fatal("Failed to connect to new control master");
1024 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1025 error("%s: open(\"/dev/null\"): %s", __func__,
1028 if (dup2(devnull, STDIN_FILENO) == -1 ||
1029 dup2(devnull, STDOUT_FILENO) == -1)
1030 error("%s: dup2: %s", __func__, strerror(errno));
1031 if (devnull > STDERR_FILENO)
1034 setproctitle("%s [mux]", options.control_path);
1037 /* Do fork() after authentication. Used by "ssh -f" */
1041 if (need_controlpersist_detach)
1042 control_persist_detach();
1043 debug("forking to background");
1044 fork_after_authentication_flag = 0;
1045 if (daemon(1, 1) < 0)
1046 fatal("daemon() failed: %.200s", strerror(errno));
1049 /* Callback for remote forward global requests */
1051 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1053 Forward *rfwd = (Forward *)ctxt;
1055 /* XXX verbose() on failure? */
1056 debug("remote forward %s for: listen %d, connect %s:%d",
1057 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1058 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
1059 if (rfwd->listen_port == 0) {
1060 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1061 rfwd->allocated_port = packet_get_int();
1062 logit("Allocated port %u for remote forward to %s:%d",
1063 rfwd->allocated_port,
1064 rfwd->connect_host, rfwd->connect_port);
1065 channel_update_permitted_opens(rfwd->handle,
1066 rfwd->allocated_port);
1068 channel_update_permitted_opens(rfwd->handle, -1);
1072 if (type == SSH2_MSG_REQUEST_FAILURE) {
1073 if (options.exit_on_forward_failure)
1074 fatal("Error: remote port forwarding failed for "
1075 "listen port %d", rfwd->listen_port);
1077 logit("Warning: remote port forwarding failed for "
1078 "listen port %d", rfwd->listen_port);
1080 if (++remote_forward_confirms_received == options.num_remote_forwards) {
1081 debug("All remote forwarding requests processed");
1082 if (fork_after_authentication_flag)
1088 client_cleanup_stdio_fwd(int id, void *arg)
1090 debug("stdio forwarding: done");
1095 ssh_init_stdio_forwarding(void)
1100 if (stdio_forward_host == NULL)
1103 fatal("stdio forwarding require Protocol 2");
1105 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1107 if ((in = dup(STDIN_FILENO)) < 0 ||
1108 (out = dup(STDOUT_FILENO)) < 0)
1109 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1110 if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1111 stdio_forward_port, in, out)) == NULL)
1112 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1113 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1117 ssh_init_forwarding(void)
1122 /* Initiate local TCP/IP port forwardings. */
1123 for (i = 0; i < options.num_local_forwards; i++) {
1124 debug("Local connections to %.200s:%d forwarded to remote "
1125 "address %.200s:%d",
1126 (options.local_forwards[i].listen_host == NULL) ?
1127 (options.gateway_ports ? "*" : "LOCALHOST") :
1128 options.local_forwards[i].listen_host,
1129 options.local_forwards[i].listen_port,
1130 options.local_forwards[i].connect_host,
1131 options.local_forwards[i].connect_port);
1132 success += channel_setup_local_fwd_listener(
1133 options.local_forwards[i].listen_host,
1134 options.local_forwards[i].listen_port,
1135 options.local_forwards[i].connect_host,
1136 options.local_forwards[i].connect_port,
1137 options.gateway_ports);
1139 if (i > 0 && success != i && options.exit_on_forward_failure)
1140 fatal("Could not request local forwarding.");
1141 if (i > 0 && success == 0)
1142 error("Could not request local forwarding.");
1144 /* Initiate remote TCP/IP port forwardings. */
1145 for (i = 0; i < options.num_remote_forwards; i++) {
1146 debug("Remote connections from %.200s:%d forwarded to "
1147 "local address %.200s:%d",
1148 (options.remote_forwards[i].listen_host == NULL) ?
1149 "LOCALHOST" : options.remote_forwards[i].listen_host,
1150 options.remote_forwards[i].listen_port,
1151 options.remote_forwards[i].connect_host,
1152 options.remote_forwards[i].connect_port);
1153 options.remote_forwards[i].handle =
1154 channel_request_remote_forwarding(
1155 options.remote_forwards[i].listen_host,
1156 options.remote_forwards[i].listen_port,
1157 options.remote_forwards[i].connect_host,
1158 options.remote_forwards[i].connect_port);
1159 if (options.remote_forwards[i].handle < 0) {
1160 if (options.exit_on_forward_failure)
1161 fatal("Could not request remote forwarding.");
1163 logit("Warning: Could not request remote "
1166 client_register_global_confirm(ssh_confirm_remote_forward,
1167 &options.remote_forwards[i]);
1171 /* Initiate tunnel forwarding. */
1172 if (options.tun_open != SSH_TUNMODE_NO) {
1173 if (client_request_tun_fwd(options.tun_open,
1174 options.tun_local, options.tun_remote) == -1) {
1175 if (options.exit_on_forward_failure)
1176 fatal("Could not request tunnel forwarding.");
1178 error("Could not request tunnel forwarding.");
1184 check_agent_present(void)
1186 if (options.forward_agent) {
1187 /* Clear agent forwarding if we don't have an agent. */
1188 if (!ssh_agent_present())
1189 options.forward_agent = 0;
1197 int interactive = 0;
1201 const char *display;
1203 /* Enable compression if requested. */
1204 if (options.compression) {
1205 debug("Requesting compression at level %d.",
1206 options.compression_level);
1208 if (options.compression_level < 1 ||
1209 options.compression_level > 9)
1210 fatal("Compression level must be from 1 (fast) to "
1213 /* Send the request. */
1214 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1215 packet_put_int(options.compression_level);
1217 packet_write_wait();
1218 type = packet_read();
1219 if (type == SSH_SMSG_SUCCESS)
1220 packet_start_compression(options.compression_level);
1221 else if (type == SSH_SMSG_FAILURE)
1222 logit("Warning: Remote host refused compression.");
1224 packet_disconnect("Protocol error waiting for "
1225 "compression response.");
1227 /* Allocate a pseudo tty if appropriate. */
1229 debug("Requesting pty.");
1231 /* Start the packet. */
1232 packet_start(SSH_CMSG_REQUEST_PTY);
1234 /* Store TERM in the packet. There is no limit on the
1235 length of the string. */
1236 cp = getenv("TERM");
1239 packet_put_cstring(cp);
1241 /* Store window size in the packet. */
1242 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1243 memset(&ws, 0, sizeof(ws));
1244 packet_put_int((u_int)ws.ws_row);
1245 packet_put_int((u_int)ws.ws_col);
1246 packet_put_int((u_int)ws.ws_xpixel);
1247 packet_put_int((u_int)ws.ws_ypixel);
1249 /* Store tty modes in the packet. */
1250 tty_make_modes(fileno(stdin), NULL);
1252 /* Send the packet, and wait for it to leave. */
1254 packet_write_wait();
1256 /* Read response from the server. */
1257 type = packet_read();
1258 if (type == SSH_SMSG_SUCCESS) {
1261 } else if (type == SSH_SMSG_FAILURE)
1262 logit("Warning: Remote host failed or refused to "
1263 "allocate a pseudo tty.");
1265 packet_disconnect("Protocol error waiting for pty "
1266 "request response.");
1268 /* Request X11 forwarding if enabled and DISPLAY is set. */
1269 display = getenv("DISPLAY");
1270 if (options.forward_x11 && display != NULL) {
1272 /* Get reasonable local authentication information. */
1273 client_x11_get_proto(display, options.xauth_location,
1274 options.forward_x11_trusted,
1275 options.forward_x11_timeout,
1277 /* Request forwarding with authentication spoofing. */
1278 debug("Requesting X11 forwarding with authentication "
1280 x11_request_forwarding_with_spoofing(0, display, proto,
1282 /* Read response from the server. */
1283 type = packet_read();
1284 if (type == SSH_SMSG_SUCCESS) {
1286 } else if (type == SSH_SMSG_FAILURE) {
1287 logit("Warning: Remote host denied X11 forwarding.");
1289 packet_disconnect("Protocol error waiting for X11 "
1293 /* Tell the packet module whether this is an interactive session. */
1294 packet_set_interactive(interactive,
1295 options.ip_qos_interactive, options.ip_qos_bulk);
1297 /* Request authentication agent forwarding if appropriate. */
1298 check_agent_present();
1300 if (options.forward_agent) {
1301 debug("Requesting authentication agent forwarding.");
1302 auth_request_forwarding();
1304 /* Read response from the server. */
1305 type = packet_read();
1307 if (type != SSH_SMSG_SUCCESS)
1308 logit("Warning: Remote host denied authentication agent forwarding.");
1311 /* Initiate port forwardings. */
1312 ssh_init_stdio_forwarding();
1313 ssh_init_forwarding();
1315 /* Execute a local command */
1316 if (options.local_command != NULL &&
1317 options.permit_local_command)
1318 ssh_local_cmd(options.local_command);
1321 * If requested and we are not interested in replies to remote
1322 * forwarding requests, then let ssh continue in the background.
1324 if (fork_after_authentication_flag) {
1325 if (options.exit_on_forward_failure &&
1326 options.num_remote_forwards > 0) {
1327 debug("deferring postauth fork until remote forward "
1328 "confirmation received");
1334 * If a command was specified on the command line, execute the
1335 * command now. Otherwise request the server to start a shell.
1337 if (buffer_len(&command) > 0) {
1338 int len = buffer_len(&command);
1341 debug("Sending command: %.*s", len,
1342 (u_char *)buffer_ptr(&command));
1343 packet_start(SSH_CMSG_EXEC_CMD);
1344 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1346 packet_write_wait();
1348 debug("Requesting shell.");
1349 packet_start(SSH_CMSG_EXEC_SHELL);
1351 packet_write_wait();
1354 /* Enter the interactive session. */
1355 return client_loop(have_tty, tty_flag ?
1356 options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1359 /* request pty/x11/agent/tcpfwd/shell for channel */
1361 ssh_session2_setup(int id, int success, void *arg)
1363 extern char **environ;
1364 const char *display;
1365 int interactive = tty_flag;
1368 return; /* No need for error message, channels code sens one */
1370 display = getenv("DISPLAY");
1371 if (options.forward_x11 && display != NULL) {
1373 /* Get reasonable local authentication information. */
1374 client_x11_get_proto(display, options.xauth_location,
1375 options.forward_x11_trusted,
1376 options.forward_x11_timeout, &proto, &data);
1377 /* Request forwarding with authentication spoofing. */
1378 debug("Requesting X11 forwarding with authentication "
1380 x11_request_forwarding_with_spoofing(id, display, proto,
1382 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1383 /* XXX exit_on_forward_failure */
1387 check_agent_present();
1388 if (options.forward_agent) {
1389 debug("Requesting authentication agent forwarding.");
1390 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1394 /* Tell the packet module whether this is an interactive session. */
1395 packet_set_interactive(interactive,
1396 options.ip_qos_interactive, options.ip_qos_bulk);
1398 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1399 NULL, fileno(stdin), &command, environ);
1402 /* open new channel for a session */
1404 ssh_session2_open(void)
1407 int window, packetmax, in, out, err;
1409 if (stdin_null_flag) {
1410 in = open(_PATH_DEVNULL, O_RDONLY);
1412 in = dup(STDIN_FILENO);
1414 out = dup(STDOUT_FILENO);
1415 err = dup(STDERR_FILENO);
1417 if (in < 0 || out < 0 || err < 0)
1418 fatal("dup() in/out/err failed");
1420 /* enable nonblocking unless tty */
1429 * We need to check to see what to do about buffer sizes here.
1430 * - In an HPN to non-HPN connection we want to limit the window size to
1431 * something reasonable in case the far side has the large window bug.
1432 * - In an HPN to HPN connection we want to use the max window size but
1433 * allow the user to override it.
1434 * - Lastly if HPN is disabled then use the ssh standard window size.
1436 * We cannot just do a getsockopt() here and set the ssh window to that
1437 * as in case of autotuning of socket buffers the window would get stuck
1438 * at the initial buffer size, generally less than 96k. Therefore we
1439 * need to set the maximum ssh window size to the maximum HPN buffer
1440 * size unless the user has set TcpRcvBufPoll to no. In that case we
1441 * can just set the window to the minimum of HPN buffer size and TCP
1442 * receive buffer size.
1445 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1447 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT;
1449 if (datafellows & SSH_BUG_LARGEWINDOW) {
1450 debug("HPN to Non-HPN Connection");
1451 } else if (options.tcp_rcv_buf_poll <= 0) {
1452 sock_get_rcvbuf(&options.hpn_buffer_size, 0);
1453 debug("HPNBufferSize set to TCP RWIN: %d",
1454 options.hpn_buffer_size);
1455 } else if (options.tcp_rcv_buf > 0) {
1456 sock_get_rcvbuf(&options.hpn_buffer_size,
1457 options.tcp_rcv_buf);
1458 debug("HPNBufferSize set to user TCPRcvBuf: %d",
1459 options.hpn_buffer_size);
1461 debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1462 channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1463 window = options.hpn_buffer_size;
1465 packetmax = CHAN_SES_PACKET_DEFAULT;
1467 window = CHAN_SES_WINDOW_DEFAULT;
1472 "session", SSH_CHANNEL_OPENING, in, out, err,
1473 window, packetmax, CHAN_EXTENDED_WRITE,
1474 "client-session", /*nonblock*/0);
1475 if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) {
1476 c->dynamic_window = 1;
1477 debug("Enabled Dynamic Window Scaling\n");
1480 debug3("ssh_session2_open: channel_new: %d", c->self);
1482 channel_send_open(c->self);
1484 channel_register_open_confirm(c->self,
1485 ssh_session2_setup, NULL);
1495 /* XXX should be pre-session */
1496 if (!options.control_persist)
1497 ssh_init_stdio_forwarding();
1498 ssh_init_forwarding();
1500 /* Start listening for multiplex clients */
1504 * If we are in control persist mode and have a working mux listen
1505 * socket, then prepare to background ourselves and have a foreground
1506 * client attach as a control slave.
1507 * NB. we must save copies of the flags that we override for
1508 * the backgrounding, since we defer attachment of the slave until
1509 * after the connection is fully established (in particular,
1510 * async rfwd replies have been received for ExitOnForwardFailure).
1512 if (options.control_persist && muxserver_sock != -1) {
1513 ostdin_null_flag = stdin_null_flag;
1514 ono_shell_flag = no_shell_flag;
1515 orequest_tty = options.request_tty;
1516 otty_flag = tty_flag;
1517 stdin_null_flag = 1;
1520 if (!fork_after_authentication_flag)
1521 need_controlpersist_detach = 1;
1522 fork_after_authentication_flag = 1;
1525 * ControlPersist mux listen socket setup failed, attempt the
1526 * stdio forward setup that we skipped earlier.
1528 if (options.control_persist && muxserver_sock == -1)
1529 ssh_init_stdio_forwarding();
1531 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1532 id = ssh_session2_open();
1534 /* If we don't expect to open a new session, then disallow it */
1535 if (options.control_master == SSHCTL_MASTER_NO &&
1536 (datafellows & SSH_NEW_OPENSSH)) {
1537 debug("Requesting no-more-sessions@openssh.com");
1538 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1539 packet_put_cstring("no-more-sessions@openssh.com");
1544 /* Execute a local command */
1545 if (options.local_command != NULL &&
1546 options.permit_local_command)
1547 ssh_local_cmd(options.local_command);
1550 * If requested and we are not interested in replies to remote
1551 * forwarding requests, then let ssh continue in the background.
1553 if (fork_after_authentication_flag) {
1554 if (options.exit_on_forward_failure &&
1555 options.num_remote_forwards > 0) {
1556 debug("deferring postauth fork until remote forward "
1557 "confirmation received");
1562 if (options.use_roaming)
1565 return client_loop(tty_flag, tty_flag ?
1566 options.escape_char : SSH_ESCAPECHAR_NONE, id);
1570 load_public_identity_files(void)
1572 char *filename, *cp, thishost[NI_MAXHOST];
1573 char *pwdir = NULL, *pwname = NULL;
1578 char *identity_files[SSH_MAX_IDENTITY_FILES];
1579 Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1580 #ifdef ENABLE_PKCS11
1586 bzero(identity_files, sizeof(identity_files));
1587 bzero(identity_keys, sizeof(identity_keys));
1589 #ifdef ENABLE_PKCS11
1590 if (options.pkcs11_provider != NULL &&
1591 options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1592 (pkcs11_init(!options.batch_mode) == 0) &&
1593 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1595 for (i = 0; i < nkeys; i++) {
1596 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1600 identity_keys[n_ids] = keys[i];
1601 identity_files[n_ids] =
1602 xstrdup(options.pkcs11_provider); /* XXX */
1607 #endif /* ENABLE_PKCS11 */
1608 if ((pw = getpwuid(original_real_uid)) == NULL)
1609 fatal("load_public_identity_files: getpwuid failed");
1610 pwname = xstrdup(pw->pw_name);
1611 pwdir = xstrdup(pw->pw_dir);
1612 if (gethostname(thishost, sizeof(thishost)) == -1)
1613 fatal("load_public_identity_files: gethostname: %s",
1615 for (i = 0; i < options.num_identity_files; i++) {
1616 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
1617 strcasecmp(options.identity_files[i], "none") == 0) {
1618 xfree(options.identity_files[i]);
1621 cp = tilde_expand_filename(options.identity_files[i],
1623 filename = percent_expand(cp, "d", pwdir,
1624 "u", pwname, "l", thishost, "h", host,
1625 "r", options.user, (char *)NULL);
1627 public = key_load_public(filename, NULL);
1628 debug("identity file %s type %d", filename,
1629 public ? public->type : -1);
1630 xfree(options.identity_files[i]);
1631 identity_files[n_ids] = filename;
1632 identity_keys[n_ids] = public;
1634 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1637 /* Try to add the certificate variant too */
1638 xasprintf(&cp, "%s-cert", filename);
1639 public = key_load_public(cp, NULL);
1640 debug("identity file %s type %d", cp,
1641 public ? public->type : -1);
1642 if (public == NULL) {
1646 if (!key_is_cert(public)) {
1647 debug("%s: key %s type %s is not a certificate",
1648 __func__, cp, key_type(public));
1653 identity_keys[n_ids] = public;
1654 /* point to the original path, most likely the private key */
1655 identity_files[n_ids] = xstrdup(filename);
1658 options.num_identity_files = n_ids;
1659 memcpy(options.identity_files, identity_files, sizeof(identity_files));
1660 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1662 bzero(pwname, strlen(pwname));
1664 bzero(pwdir, strlen(pwdir));
1669 main_sigchld_handler(int sig)
1671 int save_errno = errno;
1675 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1676 (pid < 0 && errno == EINTR))
1679 signal(sig, main_sigchld_handler);