/* * 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. * * 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 1.100 2001/03/01 22:46:37 markus 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 "uidswap.h" #include "channels.h" #include "key.h" #include "authfd.h" #include "authfile.h" #include "pathnames.h" #include "clientloop.h" #include "log.h" #include "readconf.h" #include "sshconnect.h" #include "tildexpand.h" #include "dispatch.h" #include "misc.h" #include "kex.h" #include "mac.h" extern char *__progname; /* Flag indicating whether IPv4 or IPv6. This can be set on the command line. Default value is AF_UNSPEC means both IPv4 and IPv6. */ int IPv4or6 = AF_UNSPEC; /* 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 pasphrase 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; /* * 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; /* * Flag to indicate that we have received a window change signal which has * not yet been processed. This will cause a message indicating the new * window size to be sent to the server a little later. This is volatile * because this is updated in a signal handler. */ volatile int received_window_change_signal = 0; /* Flag indicating whether we have a valid host private key loaded. */ int host_private_key_loaded = 0; /* Host private key. */ RSA *host_private_key = NULL; /* Original real UID. */ uid_t original_real_uid; /* command to be executed */ Buffer command; /* Should we execute a command or invoke a subsystem? */ int subsystem_flag = 0; /* Prints a help message to the user. This function never returns. */ void usage(void) { fprintf(stderr, "Usage: %s [options] host [command]\n", __progname); fprintf(stderr, "Options:\n"); fprintf(stderr, " -l user Log in using this user name.\n"); fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n"); fprintf(stderr, " -A Enable authentication agent forwarding.\n"); fprintf(stderr, " -a Disable authentication agent forwarding.\n"); #ifdef AFS fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n"); #endif /* AFS */ fprintf(stderr, " -X Enable X11 connection forwarding.\n"); fprintf(stderr, " -x Disable X11 connection forwarding.\n"); fprintf(stderr, " -i file Identity for public key authentication " "(default: ~/.ssh/identity)\n"); fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n"); fprintf(stderr, " -T Do not allocate a tty.\n"); fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); fprintf(stderr, " Multiple -v increases verbosity.\n"); fprintf(stderr, " -V Display version number only.\n"); fprintf(stderr, " -P Don't allocate a privileged port.\n"); fprintf(stderr, " -q Quiet; don't display any warning messages.\n"); fprintf(stderr, " -f Fork into background after authentication.\n"); fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n"); fprintf(stderr, " -c cipher Select encryption algorithm: " "``3des'', ``blowfish''\n"); fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n"); fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n"); fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n"); fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname); fprintf(stderr, " forward them to the other side by connecting to host:port.\n"); fprintf(stderr, " -C Enable compression.\n"); fprintf(stderr, " -N Do not execute a shell or command.\n"); fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n"); fprintf(stderr, " -1 Force protocol version 1.\n"); fprintf(stderr, " -2 Force protocol version 2.\n"); fprintf(stderr, " -4 Use IPv4 only.\n"); fprintf(stderr, " -6 Use IPv6 only.\n"); fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n"); fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n"); exit(1); } /* * Connects to the given host using rsh (or prints an error message and exits * if rsh is not available). This function never returns. */ void rsh_connect(char *host, char *user, Buffer * command) { char *args[10]; int i; log("Using rsh. WARNING: Connection will not be encrypted."); /* Build argument list for rsh. */ i = 0; args[i++] = _PATH_RSH; /* host may have to come after user on some systems */ args[i++] = host; if (user) { args[i++] = "-l"; args[i++] = user; } if (buffer_len(command) > 0) { buffer_append(command, "\0", 1); args[i++] = buffer_ptr(command); } args[i++] = NULL; if (debug_flag) { for (i = 0; args[i]; i++) { if (i != 0) fprintf(stderr, " "); fprintf(stderr, "%s", args[i]); } fprintf(stderr, "\n"); } execv(_PATH_RSH, args); perror(_PATH_RSH); exit(1); } int ssh_session(void); int ssh_session2(void); int guess_identity_file_type(const char *filename); /* * Main program for the ssh client. */ int main(int ac, char **av) { int i, opt, optind, exit_status, ok; u_short fwd_port, fwd_host_port; char *optarg, *cp, buf[256]; struct stat st; struct passwd *pw; int dummy; uid_t original_effective_uid; /* * 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(); /* 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)); } /* * 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). */ temporarily_use_uid(original_real_uid); /* * 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; for (optind = 1; optind < ac; optind++) { if (av[optind][0] != '-') { if (host) break; if ((cp = strchr(av[optind], '@'))) { if(cp == av[optind]) usage(); options.user = av[optind]; *cp = '\0'; host = ++cp; } else host = av[optind]; continue; } opt = av[optind][1]; if (!opt) usage(); if (strchr("eilcmpLRo", opt)) { /* options with arguments */ optarg = av[optind] + 2; if (strcmp(optarg, "") == 0) { if (optind >= ac - 1) usage(); optarg = av[++optind]; } } else { if (av[optind][2]) usage(); optarg = NULL; } switch (opt) { case '1': options.protocol = SSH_PROTO_1; break; case '2': options.protocol = SSH_PROTO_2; break; case '4': IPv4or6 = AF_INET; break; case '6': IPv4or6 = 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 'g': options.gateway_ports = 1; break; case 'P': options.use_privileged_port = 0; break; case 'a': options.forward_agent = 0; break; case 'A': options.forward_agent = 1; break; #ifdef AFS case 'k': options.kerberos_tgt_passing = 0; options.afs_token_passing = 0; break; #endif 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 't': if (tty_flag) force_tty_flag = 1; tty_flag = 1; break; case 'v': if (0 == debug_flag) { debug_flag = 1; options.log_level = SYSLOG_LEVEL_DEBUG1; } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) { options.log_level++; break; } else { fatal("Too high debugging level.\n"); } /* fallthrough */ case 'V': fprintf(stderr, "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n", SSH_VERSION, PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSLeay()); 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 = -2; 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 'p': options.port = atoi(optarg); break; case 'l': options.user = optarg; break; case 'R': if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, &fwd_host_port) != 3 && sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf, &fwd_host_port) != 3) { fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg); usage(); /* NOTREACHED */ } add_remote_forward(&options, fwd_port, buf, fwd_host_port); break; case 'L': if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, &fwd_host_port) != 3 && sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf, &fwd_host_port) != 3) { fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg); usage(); /* NOTREACHED */ } add_local_forward(&options, fwd_port, buf, fwd_host_port); 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; if (process_config_line(&options, host ? host : "", optarg, "command-line", 0, &dummy) != 0) exit(1); break; case 's': subsystem_flag = 1; break; default: usage(); } } /* 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 (optind == ac) { /* No command specified - execute shell on a tty. */ tty_flag = 1; if (subsystem_flag) { fprintf(stderr, "You must specify a subsystem to invoke."); usage(); } } else { /* A command has been specified. Store it into the buffer. */ for (i = optind; i < ac; i++) { if (i > optind) 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) log("Pseudo-terminal will not be allocated because stdin is not a terminal.\n"); tty_flag = 0; } /* Get user data. */ pw = getpwuid(original_real_uid); if (!pw) { log("You don't exist, go away!\n"); exit(1); } /* Take a copy of the returned structure. */ pw = pwcopy(pw); /* Initialize "log" output. Since we are the client all output actually goes to the terminal. */ log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0); /* Read per-user configuration file. */ snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE); read_config_file(buf, host, &options); /* Read systemwide configuration file. */ read_config_file(_PATH_HOST_CONFIG_FILE, host, &options); /* Fill configuration defaults. */ fill_default_options(&options); /* reinit */ log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0); if (options.user == NULL) options.user = xstrdup(pw->pw_name); if (options.hostname != NULL) host = options.hostname; /* Disable rhosts authentication if not running as root. */ if (original_effective_uid != 0 || !options.use_privileged_port) { debug("Rhosts Authentication disabled, " "originating port will not be trusted."); options.rhosts_authentication = 0; } /* * If using rsh has been selected, exec it now (without trying * anything else). Note that we must release privileges first. */ if (options.use_rsh) { /* * Restore our superuser privileges. This must be done * before permanently setting the uid. */ restore_uid(); /* Switch to the original uid permanently. */ permanently_set_uid(original_real_uid); /* Execute rsh. */ rsh_connect(host, options.user, &command); fatal("rsh_connect returned"); } /* Restore our superuser privileges. */ restore_uid(); /* Open a connection to the remote host. */ ok = ssh_connect(host, &hostaddr, options.port, options.connection_attempts, original_effective_uid != 0 || !options.use_privileged_port, original_real_uid, options.proxy_command); /* * 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 (ok && (options.protocol & SSH_PROTO_1)) { Key k; host_private_key = RSA_new(); k.type = KEY_RSA1; k.rsa = host_private_key; if (load_private_key(_PATH_HOST_KEY_FILE, "", &k, NULL)) host_private_key_loaded = 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. */ /* * Note that some legacy systems need to postpone the following call * to permanently_set_uid() until the private hostkey is destroyed * with RSA_free(). Otherwise the calling user could ptrace() the * process, read the private hostkey and impersonate the host. * OpenBSD does not allow ptracing of setuid processes. */ permanently_set_uid(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/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR); if (stat(buf, &st) < 0) if (mkdir(buf, 0700) < 0) error("Could not create directory '%.200s'.", buf); /* Check if the connection failed, and try "rsh" if appropriate. */ if (!ok) { if (options.port != 0) log("Secure connection to %.100s on port %hu refused%.100s.", host, options.port, options.fallback_to_rsh ? "; reverting to insecure method" : ""); else log("Secure connection to %.100s refused%.100s.", host, options.fallback_to_rsh ? "; reverting to insecure method" : ""); if (options.fallback_to_rsh) { rsh_connect(host, options.user, &command); fatal("rsh_connect returned"); } exit(1); } /* Expand ~ in options.identity_files, known host file names. */ /* XXX mem-leaks */ for (i = 0; i < options.num_identity_files; i++) { options.identity_files[i] = tilde_expand_filename(options.identity_files[i], original_real_uid); options.identity_files_type[i] = guess_identity_file_type(options.identity_files[i]); debug("identity file %s type %d", options.identity_files[i], options.identity_files_type[i]); } 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); /* Log into the remote system. This never returns if the login fails. */ ssh_login(host_private_key_loaded, host_private_key, host, (struct sockaddr *)&hostaddr, original_real_uid); /* We no longer need the host private key. Clear it now. */ if (host_private_key_loaded) RSA_free(host_private_key); /* Destroys contents safely */ exit_status = compat20 ? ssh_session2() : ssh_session(); packet_close(); return exit_status; } void x11_get_proto(char *proto, int proto_len, char *data, int data_len) { char line[512]; FILE *f; int got_data = 0, i; if (options.xauth_location) { /* Try to get Xauthority information for the display. */ snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL, options.xauth_location, getenv("DISPLAY")); f = popen(line, "r"); if (f && fgets(line, sizeof(line), f) && sscanf(line, "%*s %s %s", proto, data) == 2) got_data = 1; if (f) pclose(f); } /* * 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 rand = 0; strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len); for (i = 0; i < 16; i++) { if (i % 4 == 0) rand = arc4random(); snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff); rand >>= 8; } } } 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_request_local_forwarding( 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); } } void check_agent_present(void) { if (options.forward_agent) { /* Clear agent forwarding if we don\'t have an agent. */ int authfd = ssh_get_authentication_socket(); if (authfd < 0) options.forward_agent = 0; else ssh_close_authentication_socket(authfd); } } int ssh_session(void) { int type; int plen; 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(&plen); if (type == SSH_SMSG_SUCCESS) packet_start_compression(options.compression_level); else if (type == SSH_SMSG_FAILURE) log("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_string(cp, strlen(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)); /* Send the packet, and wait for it to leave. */ packet_send(); packet_write_wait(); /* Read response from the server. */ type = packet_read(&plen); if (type == SSH_SMSG_SUCCESS) { interactive = 1; have_tty = 1; } else if (type == SSH_SMSG_FAILURE) log("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[512], data[512]; /* Get reasonable local authentication information. */ x11_get_proto(proto, sizeof proto, data, sizeof 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(&plen); if (type == SSH_SMSG_SUCCESS) { interactive = 1; } else if (type == SSH_SMSG_FAILURE) { log("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(&plen); packet_integrity_check(plen, 0, type); if (type != SSH_SMSG_SUCCESS) log("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, 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 : -1, 0); } void client_subsystem_reply(int type, int plen, void *ctxt) { int id, len; id = packet_get_int(); len = buffer_len(&command); if (len > 900) len = 900; packet_done(); if (type == SSH2_MSG_CHANNEL_FAILURE) fatal("Request for subsystem '%.*s' failed on channel %d", len, buffer_ptr(&command), id); } void ssh_session2_callback(int id, void *arg) { int len; int interactive = 0; debug("client_init id %d arg %ld", id, (long)arg); if (no_shell_flag) goto done; if (tty_flag) { struct winsize ws; char *cp; cp = getenv("TERM"); if (!cp) cp = ""; /* Store window size in the packet. */ if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) memset(&ws, 0, sizeof(ws)); channel_request_start(id, "pty-req", 0); packet_put_cstring(cp); packet_put_int(ws.ws_col); packet_put_int(ws.ws_row); packet_put_int(ws.ws_xpixel); packet_put_int(ws.ws_ypixel); packet_put_cstring(""); /* XXX: encode terminal modes */ packet_send(); interactive = 1; /* XXX wait for reply */ } if (options.forward_x11 && getenv("DISPLAY") != NULL) { char proto[512], data[512]; /* Get reasonable local authentication information. */ x11_get_proto(proto, sizeof proto, data, sizeof 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(); } len = buffer_len(&command); if (len > 0) { if (len > 900) len = 900; if (subsystem_flag) { debug("Sending subsystem: %.*s", len, buffer_ptr(&command)); channel_request_start(id, "subsystem", /*want reply*/ 1); /* register callback for reply */ /* XXX we asume that client_loop has already been called */ dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply); dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply); } else { debug("Sending command: %.*s", len, buffer_ptr(&command)); channel_request_start(id, "exec", 0); } packet_put_string(buffer_ptr(&command), buffer_len(&command)); packet_send(); } else { channel_request(id, "shell", 0); } /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */ done: /* register different callback, etc. XXX */ packet_set_interactive(interactive); } int ssh_session2(void) { int window, packetmax, id; int 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); /* XXX should be pre-session */ 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)); window = CHAN_SES_WINDOW_DEFAULT; packetmax = CHAN_SES_PACKET_DEFAULT; if (!tty_flag) { window *= 2; packetmax *=2; } id = channel_new( "session", SSH_CHANNEL_OPENING, in, out, err, window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session"), /*nonblock*/0); channel_open(id); channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, ssh_session2_callback, (void *)0); return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id); } int guess_identity_file_type(const char *filename) { struct stat st; Key *public; int type = KEY_RSA1; /* default */ if (stat(filename, &st) < 0) { /* ignore this key */ return KEY_UNSPEC; } public = key_new(type); if (!load_public_key(filename, public, NULL)) { /* ok, so we will assume this is 'some' key */ type = KEY_UNSPEC; } key_free(public); return type; }