/* $OpenBSD: ssh.c,v 1.292 2006/08/01 23:36:12 stevesk Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * Ssh client program. This program can be used to log into a remote machine. * The software supports strong authentication, encryption, and forwarding * of X11, TCP/IP, and authentication connections. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * Copyright (c) 1999 Niels Provos. All rights reserved. * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. * * Modified to work with SSL by Niels Provos * in Canada (German citizen). * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" #include #ifdef HAVE_SYS_STAT_H # include #endif #include #include #include #include #include #include #include #include #ifdef HAVE_PATHS_H #include #endif #include #include #include #include #include #include #include #include #include #include "ssh.h" #include "ssh1.h" #include "ssh2.h" #include "compat.h" #include "cipher.h" #include "xmalloc.h" #include "packet.h" #include "buffer.h" #include "bufaux.h" #include "channels.h" #include "key.h" #include "authfd.h" #include "authfile.h" #include "pathnames.h" #include "dispatch.h" #include "clientloop.h" #include "log.h" #include "readconf.h" #include "sshconnect.h" #include "misc.h" #include "kex.h" #include "mac.h" #include "sshpty.h" #include "match.h" #include "msg.h" #include "monitor_fdpass.h" #include "uidswap.h" #include "version.h" #ifdef SMARTCARD #include "scard.h" #endif extern char *__progname; /* Flag indicating whether debug mode is on. This can be set on the command line. */ int debug_flag = 0; /* Flag indicating whether a tty should be allocated */ int tty_flag = 0; int no_tty_flag = 0; int force_tty_flag = 0; /* don't exec a shell */ int no_shell_flag = 0; /* * Flag indicating that nothing should be read from stdin. This can be set * on the command line. */ int stdin_null_flag = 0; /* * Flag indicating that ssh should fork after authentication. This is useful * so that the passphrase can be entered manually, and then ssh goes to the * background. */ int fork_after_authentication_flag = 0; /* * General data structure for command line options and options configurable * in configuration files. See readconf.h. */ Options options; /* optional user configfile */ char *config = NULL; /* * Name of the host we are connecting to. This is the name given on the * command line, or the HostName specified for the user-supplied name in a * configuration file. */ char *host; /* socket address the host resolves to */ struct sockaddr_storage hostaddr; /* Private host keys. */ Sensitive sensitive_data; /* Original real UID. */ uid_t original_real_uid; uid_t original_effective_uid; /* command to be executed */ Buffer command; /* Should we execute a command or invoke a subsystem? */ int subsystem_flag = 0; /* # of replies received for global requests */ static int client_global_request_id = 0; /* pid of proxycommand child process */ pid_t proxy_command_pid = 0; /* fd to control socket */ int control_fd = -1; /* Multiplexing control command */ static u_int mux_command = 0; /* Only used in control client mode */ volatile sig_atomic_t control_client_terminate = 0; u_int control_server_pid = 0; /* Prints a help message to the user. This function never returns. */ static void usage(void) { fprintf(stderr, "usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n" " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" " [-i identity_file] [-L [bind_address:]port:host:hostport]\n" " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" ); exit(255); } static int ssh_session(void); static int ssh_session2(void); static void load_public_identity_files(void); static void control_client(const char *path); /* * Main program for the ssh client. */ int main(int ac, char **av) { int i, opt, exit_status; char *p, *cp, *line, buf[256]; struct stat st; struct passwd *pw; int dummy; extern int optind, optreset; extern char *optarg; struct servent *sp; Forward fwd; /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ sanitise_stdfd(); __progname = ssh_get_progname(av[0]); init_rng(); /* * Save the original real uid. It will be needed later (uid-swapping * may clobber the real uid). */ original_real_uid = getuid(); original_effective_uid = geteuid(); /* * Use uid-swapping to give up root privileges for the duration of * option processing. We will re-instantiate the rights when we are * ready to create the privileged port, and will permanently drop * them when the port has been created (actually, when the connection * has been made, as we may need to create the port several times). */ PRIV_END; #ifdef HAVE_SETRLIMIT /* If we are installed setuid root be careful to not drop core. */ if (original_real_uid != original_effective_uid) { struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = 0; if (setrlimit(RLIMIT_CORE, &rlim) < 0) fatal("setrlimit failed: %.100s", strerror(errno)); } #endif /* Get user data. */ pw = getpwuid(original_real_uid); if (!pw) { logit("You don't exist, go away!"); exit(255); } /* Take a copy of the returned structure. */ pw = pwcopy(pw); /* * Set our umask to something reasonable, as some files are created * with the default umask. This will make them world-readable but * writable only by the owner, which is ok for all files for which we * don't set the modes explicitly. */ umask(022); /* Initialize option structure to indicate that no values have been set. */ initialize_options(&options); /* Parse command-line arguments. */ host = NULL; again: while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVw:XY")) != -1) { switch (opt) { case '1': options.protocol = SSH_PROTO_1; break; case '2': options.protocol = SSH_PROTO_2; break; case '4': options.address_family = AF_INET; break; case '6': options.address_family = AF_INET6; break; case 'n': stdin_null_flag = 1; break; case 'f': fork_after_authentication_flag = 1; stdin_null_flag = 1; break; case 'x': options.forward_x11 = 0; break; case 'X': options.forward_x11 = 1; break; case 'Y': options.forward_x11 = 1; options.forward_x11_trusted = 1; break; case 'g': options.gateway_ports = 1; break; case 'O': if (strcmp(optarg, "check") == 0) mux_command = SSHMUX_COMMAND_ALIVE_CHECK; else if (strcmp(optarg, "exit") == 0) mux_command = SSHMUX_COMMAND_TERMINATE; else fatal("Invalid multiplex command."); break; case 'P': /* deprecated */ options.use_privileged_port = 0; break; case 'a': options.forward_agent = 0; break; case 'A': options.forward_agent = 1; break; case 'k': options.gss_deleg_creds = 0; break; case 'i': if (stat(optarg, &st) < 0) { fprintf(stderr, "Warning: Identity file %s " "not accessible: %s.\n", optarg, strerror(errno)); break; } if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES) fatal("Too many identity files specified " "(max %d)", SSH_MAX_IDENTITY_FILES); options.identity_files[options.num_identity_files++] = xstrdup(optarg); break; case 'I': #ifdef SMARTCARD options.smartcard_device = xstrdup(optarg); #else fprintf(stderr, "no support for smartcards.\n"); #endif break; case 't': if (tty_flag) force_tty_flag = 1; tty_flag = 1; break; case 'v': if (debug_flag == 0) { debug_flag = 1; options.log_level = SYSLOG_LEVEL_DEBUG1; } else { if (options.log_level < SYSLOG_LEVEL_DEBUG3) options.log_level++; break; } /* FALLTHROUGH */ case 'V': fprintf(stderr, "%s, %s\n", SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); if (opt == 'V') exit(0); break; case 'w': if (options.tun_open == -1) options.tun_open = SSH_TUNMODE_DEFAULT; options.tun_local = a2tun(optarg, &options.tun_remote); if (options.tun_local == SSH_TUNID_ERR) { fprintf(stderr, "Bad tun device '%s'\n", optarg); exit(255); } break; case 'q': options.log_level = SYSLOG_LEVEL_QUIET; break; case 'e': if (optarg[0] == '^' && optarg[2] == 0 && (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128) options.escape_char = (u_char) optarg[1] & 31; else if (strlen(optarg) == 1) options.escape_char = (u_char) optarg[0]; else if (strcmp(optarg, "none") == 0) options.escape_char = SSH_ESCAPECHAR_NONE; else { fprintf(stderr, "Bad escape character '%s'.\n", optarg); exit(255); } break; case 'c': if (ciphers_valid(optarg)) { /* SSH2 only */ options.ciphers = xstrdup(optarg); options.cipher = SSH_CIPHER_INVALID; } else { /* SSH1 only */ options.cipher = cipher_number(optarg); if (options.cipher == -1) { fprintf(stderr, "Unknown cipher type '%s'\n", optarg); exit(255); } if (options.cipher == SSH_CIPHER_3DES) options.ciphers = "3des-cbc"; else if (options.cipher == SSH_CIPHER_BLOWFISH) options.ciphers = "blowfish-cbc"; else options.ciphers = (char *)-1; } break; case 'm': if (mac_valid(optarg)) options.macs = xstrdup(optarg); else { fprintf(stderr, "Unknown mac type '%s'\n", optarg); exit(255); } break; case 'M': if (options.control_master == SSHCTL_MASTER_YES) options.control_master = SSHCTL_MASTER_ASK; else options.control_master = SSHCTL_MASTER_YES; break; case 'p': options.port = a2port(optarg); if (options.port == 0) { fprintf(stderr, "Bad port '%s'\n", optarg); exit(255); } break; case 'l': options.user = optarg; break; case 'L': if (parse_forward(&fwd, optarg)) add_local_forward(&options, &fwd); else { fprintf(stderr, "Bad local forwarding specification '%s'\n", optarg); exit(255); } break; case 'R': if (parse_forward(&fwd, optarg)) { add_remote_forward(&options, &fwd); } else { fprintf(stderr, "Bad remote forwarding specification " "'%s'\n", optarg); exit(255); } break; case 'D': cp = p = xstrdup(optarg); memset(&fwd, '\0', sizeof(fwd)); fwd.connect_host = "socks"; if ((fwd.listen_host = hpdelim(&cp)) == NULL) { fprintf(stderr, "Bad dynamic forwarding " "specification '%.100s'\n", optarg); exit(255); } if (cp != NULL) { fwd.listen_port = a2port(cp); fwd.listen_host = cleanhostname(fwd.listen_host); } else { fwd.listen_port = a2port(fwd.listen_host); fwd.listen_host = NULL; } if (fwd.listen_port == 0) { fprintf(stderr, "Bad dynamic port '%s'\n", optarg); exit(255); } add_local_forward(&options, &fwd); xfree(p); break; case 'C': options.compression = 1; break; case 'N': no_shell_flag = 1; no_tty_flag = 1; break; case 'T': no_tty_flag = 1; break; case 'o': dummy = 1; line = xstrdup(optarg); if (process_config_line(&options, host ? host : "", line, "command-line", 0, &dummy) != 0) exit(255); xfree(line); break; case 's': subsystem_flag = 1; break; case 'S': if (options.control_path != NULL) free(options.control_path); options.control_path = xstrdup(optarg); break; case 'b': options.bind_address = optarg; break; case 'F': config = optarg; break; default: usage(); } } ac -= optind; av += optind; if (ac > 0 && !host && **av != '-') { if (strrchr(*av, '@')) { p = xstrdup(*av); cp = strrchr(p, '@'); if (cp == NULL || cp == p) usage(); options.user = p; *cp = '\0'; host = ++cp; } else host = *av; if (ac > 1) { optind = optreset = 1; goto again; } ac--, av++; } /* Check that we got a host name. */ if (!host) usage(); SSLeay_add_all_algorithms(); ERR_load_crypto_strings(); /* Initialize the command to execute on remote host. */ buffer_init(&command); /* * Save the command to execute on the remote host in a buffer. There * is no limit on the length of the command, except by the maximum * packet size. Also sets the tty flag if there is no command. */ if (!ac) { /* No command specified - execute shell on a tty. */ tty_flag = 1; if (subsystem_flag) { fprintf(stderr, "You must specify a subsystem to invoke.\n"); usage(); } } else { /* A command has been specified. Store it into the buffer. */ for (i = 0; i < ac; i++) { if (i) buffer_append(&command, " ", 1); buffer_append(&command, av[i], strlen(av[i])); } } /* Cannot fork to background if no command. */ if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag) fatal("Cannot fork into background without a command to execute."); /* Allocate a tty by default if no command specified. */ if (buffer_len(&command) == 0) tty_flag = 1; /* Force no tty */ if (no_tty_flag) tty_flag = 0; /* Do not allocate a tty if stdin is not a tty. */ if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { if (tty_flag) logit("Pseudo-terminal will not be allocated because stdin is not a terminal."); tty_flag = 0; } /* * Initialize "log" output. Since we are the client all output * actually goes to stderr. */ log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, SYSLOG_FACILITY_USER, 1); /* * Read per-user configuration file. Ignore the system wide config * file if the user specifies a config file on the command line. */ if (config != NULL) { if (!read_config_file(config, host, &options, 0)) fatal("Can't open user config file %.100s: " "%.100s", config, strerror(errno)); } else { snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE); (void)read_config_file(buf, host, &options, 1); /* Read systemwide configuration file after use config. */ (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, &options, 0); } /* Fill configuration defaults. */ fill_default_options(&options); channel_set_af(options.address_family); /* reinit */ log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1); seed_rng(); if (options.user == NULL) options.user = xstrdup(pw->pw_name); if (options.hostname != NULL) host = options.hostname; /* force lowercase for hostkey matching */ if (options.host_key_alias != NULL) { for (p = options.host_key_alias; *p; p++) if (isupper(*p)) *p = (char)tolower(*p); } /* Get default port if port has not been set. */ if (options.port == 0) { sp = getservbyname(SSH_SERVICE_NAME, "tcp"); options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; } if (options.proxy_command != NULL && strcmp(options.proxy_command, "none") == 0) options.proxy_command = NULL; if (options.control_path != NULL && strcmp(options.control_path, "none") == 0) options.control_path = NULL; if (options.control_path != NULL) { char thishost[NI_MAXHOST]; if (gethostname(thishost, sizeof(thishost)) == -1) fatal("gethostname: %s", strerror(errno)); snprintf(buf, sizeof(buf), "%d", options.port); cp = tilde_expand_filename(options.control_path, original_real_uid); options.control_path = percent_expand(cp, "p", buf, "h", host, "r", options.user, "l", thishost, (char *)NULL); xfree(cp); } if (mux_command != 0 && options.control_path == NULL) fatal("No ControlPath specified for \"-O\" command"); if (options.control_path != NULL) control_client(options.control_path); /* Open a connection to the remote host. */ if (ssh_connect(host, &hostaddr, options.port, options.address_family, options.connection_attempts, #ifdef HAVE_CYGWIN options.use_privileged_port, #else original_effective_uid == 0 && options.use_privileged_port, #endif options.proxy_command) != 0) exit(255); /* * If we successfully made the connection, load the host private key * in case we will need it later for combined rsa-rhosts * authentication. This must be done before releasing extra * privileges, because the file is only readable by root. * If we cannot access the private keys, load the public keys * instead and try to execute the ssh-keysign helper instead. */ sensitive_data.nkeys = 0; sensitive_data.keys = NULL; sensitive_data.external_keysign = 0; if (options.rhosts_rsa_authentication || options.hostbased_authentication) { sensitive_data.nkeys = 3; sensitive_data.keys = xcalloc(sensitive_data.nkeys, sizeof(Key)); PRIV_START; sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, _PATH_HOST_KEY_FILE, "", NULL, NULL); sensitive_data.keys[1] = key_load_private_type(KEY_DSA, _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); sensitive_data.keys[2] = key_load_private_type(KEY_RSA, _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); PRIV_END; if (options.hostbased_authentication == 1 && sensitive_data.keys[0] == NULL && sensitive_data.keys[1] == NULL && sensitive_data.keys[2] == NULL) { sensitive_data.keys[1] = key_load_public( _PATH_HOST_DSA_KEY_FILE, NULL); sensitive_data.keys[2] = key_load_public( _PATH_HOST_RSA_KEY_FILE, NULL); sensitive_data.external_keysign = 1; } } /* * Get rid of any extra privileges that we may have. We will no * longer need them. Also, extra privileges could make it very hard * to read identity files and other non-world-readable files from the * user's home directory if it happens to be on a NFS volume where * root is mapped to nobody. */ if (original_effective_uid == 0) { PRIV_START; permanently_set_uid(pw); } /* * Now that we are back to our own permissions, create ~/.ssh * directory if it doesn't already exist. */ snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); if (stat(buf, &st) < 0) if (mkdir(buf, 0700) < 0) error("Could not create directory '%.200s'.", buf); /* load options.identity_files */ load_public_identity_files(); /* Expand ~ in known host file names. */ /* XXX mem-leaks: */ options.system_hostfile = tilde_expand_filename(options.system_hostfile, original_real_uid); options.user_hostfile = tilde_expand_filename(options.user_hostfile, original_real_uid); options.system_hostfile2 = tilde_expand_filename(options.system_hostfile2, original_real_uid); options.user_hostfile2 = tilde_expand_filename(options.user_hostfile2, original_real_uid); signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ /* Log into the remote system. This never returns if the login fails. */ ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw); /* We no longer need the private host keys. Clear them now. */ if (sensitive_data.nkeys != 0) { for (i = 0; i < sensitive_data.nkeys; i++) { if (sensitive_data.keys[i] != NULL) { /* Destroys contents safely */ debug3("clear hostkey %d", i); key_free(sensitive_data.keys[i]); sensitive_data.keys[i] = NULL; } } xfree(sensitive_data.keys); } for (i = 0; i < options.num_identity_files; i++) { if (options.identity_files[i]) { xfree(options.identity_files[i]); options.identity_files[i] = NULL; } if (options.identity_keys[i]) { key_free(options.identity_keys[i]); options.identity_keys[i] = NULL; } } exit_status = compat20 ? ssh_session2() : ssh_session(); packet_close(); if (options.control_path != NULL && control_fd != -1) unlink(options.control_path); /* * Send SIGHUP to proxy command if used. We don't wait() in * case it hangs and instead rely on init to reap the child */ if (proxy_command_pid > 1) kill(proxy_command_pid, SIGHUP); return exit_status; } static void ssh_init_forwarding(void) { int success = 0; int i; /* Initiate local TCP/IP port forwardings. */ for (i = 0; i < options.num_local_forwards; i++) { debug("Local connections to %.200s:%d forwarded to remote " "address %.200s:%d", (options.local_forwards[i].listen_host == NULL) ? (options.gateway_ports ? "*" : "LOCALHOST") : options.local_forwards[i].listen_host, options.local_forwards[i].listen_port, options.local_forwards[i].connect_host, options.local_forwards[i].connect_port); success += channel_setup_local_fwd_listener( options.local_forwards[i].listen_host, options.local_forwards[i].listen_port, options.local_forwards[i].connect_host, options.local_forwards[i].connect_port, options.gateway_ports); } if (i > 0 && success != i && options.exit_on_forward_failure) fatal("Could not request local forwarding."); if (i > 0 && success == 0) error("Could not request local forwarding."); /* Initiate remote TCP/IP port forwardings. */ for (i = 0; i < options.num_remote_forwards; i++) { debug("Remote connections from %.200s:%d forwarded to " "local address %.200s:%d", (options.remote_forwards[i].listen_host == NULL) ? "LOCALHOST" : options.remote_forwards[i].listen_host, options.remote_forwards[i].listen_port, options.remote_forwards[i].connect_host, options.remote_forwards[i].connect_port); if (channel_request_remote_forwarding( options.remote_forwards[i].listen_host, options.remote_forwards[i].listen_port, options.remote_forwards[i].connect_host, options.remote_forwards[i].connect_port) < 0) { if (options.exit_on_forward_failure) fatal("Could not request remote forwarding."); else logit("Warning: Could not request remote " "forwarding."); } } } static void check_agent_present(void) { if (options.forward_agent) { /* Clear agent forwarding if we don't have an agent. */ if (!ssh_agent_present()) options.forward_agent = 0; } } static int ssh_session(void) { int type; int interactive = 0; int have_tty = 0; struct winsize ws; char *cp; const char *display; /* Enable compression if requested. */ if (options.compression) { debug("Requesting compression at level %d.", options.compression_level); if (options.compression_level < 1 || options.compression_level > 9) fatal("Compression level must be from 1 (fast) to 9 (slow, best)."); /* Send the request. */ packet_start(SSH_CMSG_REQUEST_COMPRESSION); packet_put_int(options.compression_level); packet_send(); packet_write_wait(); type = packet_read(); if (type == SSH_SMSG_SUCCESS) packet_start_compression(options.compression_level); else if (type == SSH_SMSG_FAILURE) logit("Warning: Remote host refused compression."); else packet_disconnect("Protocol error waiting for compression response."); } /* Allocate a pseudo tty if appropriate. */ if (tty_flag) { debug("Requesting pty."); /* Start the packet. */ packet_start(SSH_CMSG_REQUEST_PTY); /* Store TERM in the packet. There is no limit on the length of the string. */ cp = getenv("TERM"); if (!cp) cp = ""; packet_put_cstring(cp); /* Store window size in the packet. */ if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) memset(&ws, 0, sizeof(ws)); packet_put_int((u_int)ws.ws_row); packet_put_int((u_int)ws.ws_col); packet_put_int((u_int)ws.ws_xpixel); packet_put_int((u_int)ws.ws_ypixel); /* Store tty modes in the packet. */ tty_make_modes(fileno(stdin), NULL); /* Send the packet, and wait for it to leave. */ packet_send(); packet_write_wait(); /* Read response from the server. */ type = packet_read(); if (type == SSH_SMSG_SUCCESS) { interactive = 1; have_tty = 1; } else if (type == SSH_SMSG_FAILURE) logit("Warning: Remote host failed or refused to allocate a pseudo tty."); else packet_disconnect("Protocol error waiting for pty request response."); } /* Request X11 forwarding if enabled and DISPLAY is set. */ display = getenv("DISPLAY"); if (options.forward_x11 && display != NULL) { char *proto, *data; /* Get reasonable local authentication information. */ client_x11_get_proto(display, options.xauth_location, options.forward_x11_trusted, &proto, &data); /* Request forwarding with authentication spoofing. */ debug("Requesting X11 forwarding with authentication spoofing."); x11_request_forwarding_with_spoofing(0, display, proto, data); /* Read response from the server. */ type = packet_read(); if (type == SSH_SMSG_SUCCESS) { interactive = 1; } else if (type == SSH_SMSG_FAILURE) { logit("Warning: Remote host denied X11 forwarding."); } else { packet_disconnect("Protocol error waiting for X11 forwarding"); } } /* Tell the packet module whether this is an interactive session. */ packet_set_interactive(interactive); /* Request authentication agent forwarding if appropriate. */ check_agent_present(); if (options.forward_agent) { debug("Requesting authentication agent forwarding."); auth_request_forwarding(); /* Read response from the server. */ type = packet_read(); packet_check_eom(); if (type != SSH_SMSG_SUCCESS) logit("Warning: Remote host denied authentication agent forwarding."); } /* Initiate port forwardings. */ ssh_init_forwarding(); /* If requested, let ssh continue in the background. */ if (fork_after_authentication_flag) if (daemon(1, 1) < 0) fatal("daemon() failed: %.200s", strerror(errno)); /* * If a command was specified on the command line, execute the * command now. Otherwise request the server to start a shell. */ if (buffer_len(&command) > 0) { int len = buffer_len(&command); if (len > 900) len = 900; debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); packet_start(SSH_CMSG_EXEC_CMD); packet_put_string(buffer_ptr(&command), buffer_len(&command)); packet_send(); packet_write_wait(); } else { debug("Requesting shell."); packet_start(SSH_CMSG_EXEC_SHELL); packet_send(); packet_write_wait(); } /* Enter the interactive session. */ return client_loop(have_tty, tty_flag ? options.escape_char : SSH_ESCAPECHAR_NONE, 0); } static void ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt) { int id, len; id = packet_get_int(); len = buffer_len(&command); if (len > 900) len = 900; packet_check_eom(); if (type == SSH2_MSG_CHANNEL_FAILURE) fatal("Request for subsystem '%.*s' failed on channel %d", len, (u_char *)buffer_ptr(&command), id); } void client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt) { int i; i = client_global_request_id++; if (i >= options.num_remote_forwards) return; debug("remote forward %s for: listen %d, connect %s:%d", type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", options.remote_forwards[i].listen_port, options.remote_forwards[i].connect_host, options.remote_forwards[i].connect_port); if (type == SSH2_MSG_REQUEST_FAILURE) { if (options.exit_on_forward_failure) fatal("Error: remote port forwarding failed for " "listen port %d", options.remote_forwards[i].listen_port); else logit("Warning: remote port forwarding failed for " "listen port %d", options.remote_forwards[i].listen_port); } } static void ssh_control_listener(void) { struct sockaddr_un addr; mode_t old_umask; int addr_len; if (options.control_path == NULL || options.control_master == SSHCTL_MASTER_NO) return; debug("setting up multiplex master socket"); memset(&addr, '\0', sizeof(addr)); addr.sun_family = AF_UNIX; addr_len = offsetof(struct sockaddr_un, sun_path) + strlen(options.control_path) + 1; if (strlcpy(addr.sun_path, options.control_path, sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) fatal("ControlPath too long"); if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) fatal("%s socket(): %s", __func__, strerror(errno)); old_umask = umask(0177); if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) { control_fd = -1; if (errno == EINVAL || errno == EADDRINUSE) fatal("ControlSocket %s already exists", options.control_path); else fatal("%s bind(): %s", __func__, strerror(errno)); } umask(old_umask); if (listen(control_fd, 64) == -1) fatal("%s listen(): %s", __func__, strerror(errno)); set_nonblock(control_fd); } /* request pty/x11/agent/tcpfwd/shell for channel */ static void ssh_session2_setup(int id, void *arg) { extern char **environ; const char *display; int interactive = tty_flag; display = getenv("DISPLAY"); if (options.forward_x11 && display != NULL) { char *proto, *data; /* Get reasonable local authentication information. */ client_x11_get_proto(display, options.xauth_location, options.forward_x11_trusted, &proto, &data); /* Request forwarding with authentication spoofing. */ debug("Requesting X11 forwarding with authentication spoofing."); x11_request_forwarding_with_spoofing(id, display, proto, data); interactive = 1; /* XXX wait for reply */ } check_agent_present(); if (options.forward_agent) { debug("Requesting authentication agent forwarding."); channel_request_start(id, "auth-agent-req@openssh.com", 0); packet_send(); } if (options.tun_open != SSH_TUNMODE_NO) { Channel *c; int fd; debug("Requesting tun."); if ((fd = tun_open(options.tun_local, options.tun_open)) >= 0) { c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); c->datagram = 1; #if defined(SSH_TUN_FILTER) if (options.tun_open == SSH_TUNMODE_POINTOPOINT) channel_register_filter(c->self, sys_tun_infilter, sys_tun_outfilter); #endif packet_start(SSH2_MSG_CHANNEL_OPEN); packet_put_cstring("tun@openssh.com"); packet_put_int(c->self); packet_put_int(c->local_window_max); packet_put_int(c->local_maxpacket); packet_put_int(options.tun_open); packet_put_int(options.tun_remote); packet_send(); } } client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply); packet_set_interactive(interactive); } /* open new channel for a session */ static int ssh_session2_open(void) { Channel *c; int window, packetmax, in, out, err; if (stdin_null_flag) { in = open(_PATH_DEVNULL, O_RDONLY); } else { in = dup(STDIN_FILENO); } out = dup(STDOUT_FILENO); err = dup(STDERR_FILENO); if (in < 0 || out < 0 || err < 0) fatal("dup() in/out/err failed"); /* enable nonblocking unless tty */ if (!isatty(in)) set_nonblock(in); if (!isatty(out)) set_nonblock(out); if (!isatty(err)) set_nonblock(err); window = CHAN_SES_WINDOW_DEFAULT; packetmax = CHAN_SES_PACKET_DEFAULT; if (tty_flag) { window >>= 1; packetmax >>= 1; } c = channel_new( "session", SSH_CHANNEL_OPENING, in, out, err, window, packetmax, CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); debug3("ssh_session2_open: channel_new: %d", c->self); channel_send_open(c->self); if (!no_shell_flag) channel_register_confirm(c->self, ssh_session2_setup, NULL); return c->self; } static int ssh_session2(void) { int id = -1; /* XXX should be pre-session */ ssh_init_forwarding(); ssh_control_listener(); if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) id = ssh_session2_open(); /* Execute a local command */ if (options.local_command != NULL && options.permit_local_command) ssh_local_cmd(options.local_command); /* If requested, let ssh continue in the background. */ if (fork_after_authentication_flag) if (daemon(1, 1) < 0) fatal("daemon() failed: %.200s", strerror(errno)); return client_loop(tty_flag, tty_flag ? options.escape_char : SSH_ESCAPECHAR_NONE, id); } static void load_public_identity_files(void) { char *filename, *cp, thishost[NI_MAXHOST]; int i = 0; Key *public; struct passwd *pw; #ifdef SMARTCARD Key **keys; if (options.smartcard_device != NULL && options.num_identity_files < SSH_MAX_IDENTITY_FILES && (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) { int count = 0; for (i = 0; keys[i] != NULL; i++) { count++; memmove(&options.identity_files[1], &options.identity_files[0], sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); memmove(&options.identity_keys[1], &options.identity_keys[0], sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); options.num_identity_files++; options.identity_keys[0] = keys[i]; options.identity_files[0] = sc_get_key_label(keys[i]); } if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) options.num_identity_files = SSH_MAX_IDENTITY_FILES; i = count; xfree(keys); } #endif /* SMARTCARD */ if ((pw = getpwuid(original_real_uid)) == NULL) fatal("load_public_identity_files: getpwuid failed"); if (gethostname(thishost, sizeof(thishost)) == -1) fatal("load_public_identity_files: gethostname: %s", strerror(errno)); for (; i < options.num_identity_files; i++) { cp = tilde_expand_filename(options.identity_files[i], original_real_uid); filename = percent_expand(cp, "d", pw->pw_dir, "u", pw->pw_name, "l", thishost, "h", host, "r", options.user, (char *)NULL); xfree(cp); public = key_load_public(filename, NULL); debug("identity file %s type %d", filename, public ? public->type : -1); xfree(options.identity_files[i]); options.identity_files[i] = filename; options.identity_keys[i] = public; } } static void control_client_sighandler(int signo) { control_client_terminate = signo; } static void control_client_sigrelay(int signo) { if (control_server_pid > 1) kill(control_server_pid, signo); } static int env_permitted(char *env) { int i, ret; char name[1024], *cp; if ((cp = strchr(env, '=')) == NULL || cp == env) return (0); ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env); if (ret <= 0 || (size_t)ret >= sizeof(name)) fatal("env_permitted: name '%.100s...' too long", env); for (i = 0; i < options.num_send_env; i++) if (match_pattern(name, options.send_env[i])) return (1); return (0); } static void control_client(const char *path) { struct sockaddr_un addr; int i, r, fd, sock, exitval, num_env, addr_len; Buffer m; char *term; extern char **environ; u_int flags; if (mux_command == 0) mux_command = SSHMUX_COMMAND_OPEN; switch (options.control_master) { case SSHCTL_MASTER_AUTO: case SSHCTL_MASTER_AUTO_ASK: debug("auto-mux: Trying existing master"); /* FALLTHROUGH */ case SSHCTL_MASTER_NO: break; default: return; } memset(&addr, '\0', sizeof(addr)); addr.sun_family = AF_UNIX; addr_len = offsetof(struct sockaddr_un, sun_path) + strlen(path) + 1; if (strlcpy(addr.sun_path, path, sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) fatal("ControlPath too long"); if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) fatal("%s socket(): %s", __func__, strerror(errno)); if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) { if (mux_command != SSHMUX_COMMAND_OPEN) { fatal("Control socket connect(%.100s): %s", path, strerror(errno)); } if (errno == ENOENT) debug("Control socket \"%.100s\" does not exist", path); else { error("Control socket connect(%.100s): %s", path, strerror(errno)); } close(sock); return; } if (stdin_null_flag) { if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1) fatal("open(/dev/null): %s", strerror(errno)); if (dup2(fd, STDIN_FILENO) == -1) fatal("dup2: %s", strerror(errno)); if (fd > STDERR_FILENO) close(fd); } term = getenv("TERM"); flags = 0; if (tty_flag) flags |= SSHMUX_FLAG_TTY; if (subsystem_flag) flags |= SSHMUX_FLAG_SUBSYS; if (options.forward_x11) flags |= SSHMUX_FLAG_X11_FWD; if (options.forward_agent) flags |= SSHMUX_FLAG_AGENT_FWD; buffer_init(&m); /* Send our command to server */ buffer_put_int(&m, mux_command); buffer_put_int(&m, flags); if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) fatal("%s: msg_send", __func__); buffer_clear(&m); /* Get authorisation status and PID of controlee */ if (ssh_msg_recv(sock, &m) == -1) fatal("%s: msg_recv", __func__); if (buffer_get_char(&m) != SSHMUX_VER) fatal("%s: wrong version", __func__); if (buffer_get_int(&m) != 1) fatal("Connection to master denied"); control_server_pid = buffer_get_int(&m); buffer_clear(&m); switch (mux_command) { case SSHMUX_COMMAND_ALIVE_CHECK: fprintf(stderr, "Master running (pid=%d)\r\n", control_server_pid); exit(0); case SSHMUX_COMMAND_TERMINATE: fprintf(stderr, "Exit request sent.\r\n"); exit(0); case SSHMUX_COMMAND_OPEN: /* continue below */ break; default: fatal("silly mux_command %d", mux_command); } /* SSHMUX_COMMAND_OPEN */ buffer_put_cstring(&m, term ? term : ""); buffer_append(&command, "\0", 1); buffer_put_cstring(&m, buffer_ptr(&command)); if (options.num_send_env == 0 || environ == NULL) { buffer_put_int(&m, 0); } else { /* Pass environment */ num_env = 0; for (i = 0; environ[i] != NULL; i++) if (env_permitted(environ[i])) num_env++; /* Count */ buffer_put_int(&m, num_env); for (i = 0; environ[i] != NULL && num_env >= 0; i++) if (env_permitted(environ[i])) { num_env--; buffer_put_cstring(&m, environ[i]); } } if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) fatal("%s: msg_send", __func__); mm_send_fd(sock, STDIN_FILENO); mm_send_fd(sock, STDOUT_FILENO); mm_send_fd(sock, STDERR_FILENO); /* Wait for reply, so master has a chance to gather ttymodes */ buffer_clear(&m); if (ssh_msg_recv(sock, &m) == -1) fatal("%s: msg_recv", __func__); if (buffer_get_char(&m) != SSHMUX_VER) fatal("%s: wrong version", __func__); buffer_free(&m); signal(SIGHUP, control_client_sighandler); signal(SIGINT, control_client_sighandler); signal(SIGTERM, control_client_sighandler); signal(SIGWINCH, control_client_sigrelay); if (tty_flag) enter_raw_mode(); /* Stick around until the controlee closes the client_fd */ exitval = 0; for (;!control_client_terminate;) { r = read(sock, &exitval, sizeof(exitval)); if (r == 0) { debug2("Received EOF from master"); break; } if (r > 0) debug2("Received exit status from master %d", exitval); if (r == -1 && errno != EINTR) fatal("%s: read %s", __func__, strerror(errno)); } if (control_client_terminate) debug2("Exiting on signal %d", control_client_terminate); close(sock); leave_raw_mode(); if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) fprintf(stderr, "Connection to master closed.\r\n"); exit(exitval); }