/* * 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" RCSID("$OpenBSD: ssh.c,v 1.223 2004/07/11 17:48:47 deraadt Exp $"); #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" #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; /* 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 [-1246AaCfghkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n" " [-D port] [-e escape_char] [-F configfile] [-i identity_file]\n" " [-L port:host:hostport] [-l login_name] [-m mac_spec] [-o option]\n" " [-p port] [-R port:host:hostport] [-S ctl] [user@]hostname [command]\n" ); exit(1); } 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; u_short fwd_port, fwd_host_port; char sfwd_port[6], sfwd_host_port[6]; char *p, *cp, *line, buf[256]; struct stat st; struct passwd *pw; int dummy; extern int optind, optreset; extern char *optarg; /* * 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; /* 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)); } /* Get user data. */ pw = getpwuid(original_real_uid); if (!pw) { logit("You don't exist, go away!"); exit(1); } /* 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:MNPR:S:TVXY")) != -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 '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 " "does not exist.\n", optarg); 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_VERSION, SSLeay_version(SSLEAY_VERSION)); if (opt == 'V') exit(0); 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(1); } break; case 'c': if (ciphers_valid(optarg)) { /* SSH2 only */ options.ciphers = xstrdup(optarg); options.cipher = SSH_CIPHER_ILLEGAL; } else { /* SSH1 only */ options.cipher = cipher_number(optarg); if (options.cipher == -1) { fprintf(stderr, "Unknown cipher type '%s'\n", optarg); exit(1); } 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(1); } break; case 'M': options.control_master = (options.control_master >= 1) ? 2 : 1; break; case 'p': options.port = a2port(optarg); if (options.port == 0) { fprintf(stderr, "Bad port '%s'\n", optarg); exit(1); } break; case 'l': options.user = optarg; break; case 'L': case 'R': if (sscanf(optarg, "%5[0-9]:%255[^:]:%5[0-9]", sfwd_port, buf, sfwd_host_port) != 3 && sscanf(optarg, "%5[0-9]/%255[^/]/%5[0-9]", sfwd_port, buf, sfwd_host_port) != 3) { fprintf(stderr, "Bad forwarding specification '%s'\n", optarg); usage(); /* NOTREACHED */ } if ((fwd_port = a2port(sfwd_port)) == 0 || (fwd_host_port = a2port(sfwd_host_port)) == 0) { fprintf(stderr, "Bad forwarding port(s) '%s'\n", optarg); exit(1); } if (opt == 'L') add_local_forward(&options, fwd_port, buf, fwd_host_port); else if (opt == 'R') add_remote_forward(&options, fwd_port, buf, fwd_host_port); break; case 'D': fwd_port = a2port(optarg); if (fwd_port == 0) { fprintf(stderr, "Bad dynamic port '%s'\n", optarg); exit(1); } add_local_forward(&options, fwd_port, "socks", 0); 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(1); 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)) && !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); 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 = tolower(*p); } if (options.proxy_command != NULL && strcmp(options.proxy_command, "none") == 0) options.proxy_command = NULL; if (options.control_path != NULL) { options.control_path = tilde_expand_filename( options.control_path, original_real_uid); } if (options.control_path != NULL && options.control_master == 0) control_client(options.control_path); /* This doesn't return */ /* Open a connection to the remote host. */ if (ssh_connect(host, &hostaddr, options.port, options.address_family, options.connection_attempts, original_effective_uid == 0 && options.use_privileged_port, options.proxy_command) != 0) exit(1); /* * 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 = xmalloc(sensitive_data.nkeys * sizeof(Key)); PRIV_START; sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, _PATH_HOST_KEY_FILE, "", NULL); sensitive_data.keys[1] = key_load_private_type(KEY_DSA, _PATH_HOST_DSA_KEY_FILE, "", NULL); sensitive_data.keys[2] = key_load_private_type(KEY_RSA, _PATH_HOST_RSA_KEY_FILE, "", 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. */ seteuid(original_real_uid); setuid(original_real_uid); /* * 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; } #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" static void x11_get_proto(char **_proto, char **_data) { char cmd[1024]; char line[512]; char xdisplay[512]; static char proto[512], data[512]; FILE *f; int got_data = 0, generated = 0, do_unlink = 0, i; char *display, *xauthdir, *xauthfile; struct stat st; xauthdir = xauthfile = NULL; *_proto = proto; *_data = data; proto[0] = data[0] = '\0'; if (!options.xauth_location || (stat(options.xauth_location, &st) == -1)) { debug("No xauth program."); } else { if ((display = getenv("DISPLAY")) == NULL) { debug("x11_get_proto: DISPLAY not set"); return; } /* * Handle FamilyLocal case where $DISPLAY does * not match an authorization entry. For this we * just try "xauth list unix:displaynum.screennum". * XXX: "localhost" match to determine FamilyLocal * is not perfect. */ if (strncmp(display, "localhost:", 10) == 0) { snprintf(xdisplay, sizeof(xdisplay), "unix:%s", display + 10); display = xdisplay; } if (options.forward_x11_trusted == 0) { xauthdir = xmalloc(MAXPATHLEN); xauthfile = xmalloc(MAXPATHLEN); strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); if (mkdtemp(xauthdir) != NULL) { do_unlink = 1; snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", xauthdir); snprintf(cmd, sizeof(cmd), "%s -f %s generate %s " SSH_X11_PROTO " untrusted timeout 1200 2>" _PATH_DEVNULL, options.xauth_location, xauthfile, display); debug2("x11_get_proto: %s", cmd); if (system(cmd) == 0) generated = 1; } } snprintf(cmd, sizeof(cmd), "%s %s%s list %s . 2>" _PATH_DEVNULL, options.xauth_location, generated ? "-f " : "" , generated ? xauthfile : "", display); debug2("x11_get_proto: %s", cmd); f = popen(cmd, "r"); if (f && fgets(line, sizeof(line), f) && sscanf(line, "%*s %511s %511s", proto, data) == 2) got_data = 1; if (f) pclose(f); } if (do_unlink) { unlink(xauthfile); rmdir(xauthdir); } if (xauthdir) xfree(xauthdir); if (xauthfile) xfree(xauthfile); /* * If we didn't get authentication data, just make up some * data. The forwarding code will check the validity of the * response anyway, and substitute this data. The X11 * server, however, will ignore this fake data and use * whatever authentication mechanisms it was using otherwise * for the local connection. */ if (!got_data) { u_int32_t rnd = 0; logit("Warning: No xauth data; " "using fake authentication data for X11 forwarding."); strlcpy(proto, SSH_X11_PROTO, sizeof proto); for (i = 0; i < 16; i++) { if (i % 4 == 0) rnd = arc4random(); snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rnd & 0xff); rnd >>= 8; } } } 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("Connections to local port %d forwarded to remote address %.200s:%d", options.local_forwards[i].port, options.local_forwards[i].host, options.local_forwards[i].host_port); success += channel_setup_local_fwd_listener( options.local_forwards[i].port, options.local_forwards[i].host, options.local_forwards[i].host_port, options.gateway_ports); } 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("Connections to remote port %d forwarded to local address %.200s:%d", options.remote_forwards[i].port, options.remote_forwards[i].host, options.remote_forwards[i].host_port); channel_request_remote_forwarding( options.remote_forwards[i].port, options.remote_forwards[i].host, options.remote_forwards[i].host_port); } } 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; /* 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(ws.ws_row); packet_put_int(ws.ws_col); packet_put_int(ws.ws_xpixel); packet_put_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. */ if (options.forward_x11 && getenv("DISPLAY") != NULL) { char *proto, *data; /* Get reasonable local authentication information. */ x11_get_proto(&proto, &data); /* Request forwarding with authentication spoofing. */ debug("Requesting X11 forwarding with authentication spoofing."); x11_request_forwarding_with_spoofing(0, 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].port, options.remote_forwards[i].host, options.remote_forwards[i].host_port); if (type == SSH2_MSG_REQUEST_FAILURE) logit("Warning: remote port forwarding failed for listen port %d", options.remote_forwards[i].port); } static void ssh_control_listener(void) { struct sockaddr_un addr; mode_t old_umask; if (options.control_path == NULL || options.control_master <= 0) return; memset(&addr, '\0', sizeof(addr)); addr.sun_family = AF_UNIX; addr.sun_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\n", __func__, strerror(errno)); old_umask = umask(0177); if (bind(control_fd, (struct sockaddr*)&addr, addr.sun_len) == -1) { control_fd = -1; if (errno == EINVAL) fatal("ControlSocket %s already exists", options.control_path); else fatal("%s bind(): %s\n", __func__, strerror(errno)); } umask(old_umask); if (listen(control_fd, 64) == -1) fatal("%s listen(): %s\n", __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; int interactive = tty_flag; if (options.forward_x11 && getenv("DISPLAY") != NULL) { char *proto, *data; /* Get reasonable local authentication information. */ x11_get_proto(&proto, &data); /* Request forwarding with authentication spoofing. */ debug("Requesting X11 forwarding with authentication spoofing."); x11_request_forwarding_with_spoofing(id, 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(); } 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(); /* 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; int i = 0; Key *public; #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 */ for (; i < options.num_identity_files; i++) { filename = tilde_expand_filename(options.identity_files[i], original_real_uid); 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; char name[1024], *cp; strlcpy(name, env, sizeof(name)); if ((cp = strchr(name, '=')) == NULL) return (0); *cp = '\0'; 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, sock, exitval, num_env; Buffer m; char *cp; extern char **environ; memset(&addr, '\0', sizeof(addr)); addr.sun_family = AF_UNIX; addr.sun_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.sun_len) == -1) fatal("Couldn't connect to %s: %s", path, strerror(errno)); if ((cp = getenv("TERM")) == NULL) cp = ""; buffer_init(&m); /* Get PID of controlee */ if (ssh_msg_recv(sock, &m) == -1) fatal("%s: msg_recv", __func__); if (buffer_get_char(&m) != 0) fatal("%s: wrong version", __func__); /* Connection allowed? */ if (buffer_get_int(&m) != 1) fatal("Connection to master denied"); control_server_pid = buffer_get_int(&m); buffer_clear(&m); buffer_put_int(&m, tty_flag); buffer_put_int(&m, subsystem_flag); buffer_put_cstring(&m, cp); 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, /* version */0, &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) != 0) fatal("%s: master returned error", __func__); buffer_free(&m); 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); }