domotz-remote-pawn/src/network_tools/ssh.js

Domotz Agent

/** This file is part of Domotz Agent.
 * Copyright (C) 2016  Domotz Ltd
 *
 * Domotz Agent is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Domotz Agent is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Domotz Agent.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Created by Tommaso Latini <tommaso@domotz.com> on 06/09/16.
 *
 */

const MODULE = 'SSH_COMMAND_EXECUTOR';
const USER = 'domotz';
const PASSWORD = null;
const HOST = 'localhost';
const TTL = 3600000; // 1 hour
const SSH_BINARY = 'ssh';
const SSHPASS_BINARY = 'domotz_sshpass';
const USER_KNOWN_HOST_FILE = '/dev/null';
const HOST_KEY_CHECKING = 'no';

// To add options check ssh manual. We assume to use standard openssh client.
const OPTIONS_MAP = {
    bind_address: '-b',
    cipher_spec: '-c',
    escape_char: '-e',
    config_file: '-F',
    dynamic_port_forwarding: '-D',
    identity_file: '-i',
    pkcs11: '-I',
    login_name: '-l',
    local_port_forwarding: '-L',
    mac_spec: '-m',
    disable_remote_command: '-N',
    host_key_checking: '-oStrictHostKeyChecking=',
    user_known_host_file: '-oUserKnownHostsFile=',
    server_alive_interval: '-oServerAliveInterval=',
    server_alive_count_max: '-oServerAliveCountMax=',
    kex_algorithm: '-oKexAlgorithms=',
    ctl_cmd: '-O',
    port: '-p',
    remote_port_forwarding: '-R',
    ctl_path: '-S',
    disable_pseudo_tty_alloc: '-T'
};

module.exports.factory = function (procUtils) {

    /**
     * SSH is an external tool. It must be linked with system libraries!
     */
    function getCleanEnv() {
        var cleanedEnv = Object.create(process.env);
        cleanedEnv.LD_LIBRARY_PATH = "";
        return cleanedEnv;
    }

    function getOpt(options, names, dflt) {
        for (var i = 0; i < names.length; i++) {
            var name = names[i];
            var o = options[name];
            if (typeof o !== 'undefined') {
                delete options[name];
                return o;
            }
        }
        return dflt;
    }

    function setDefault(options, name, dflt) {
        if (typeof options[name] === 'undefined') {
            options[name] = dflt;
        }
    }

    /**
     * @param command: Command to run in ssh <OPTIONAL>
     * @param options:
     *      --> log_prefix: prefix for log [default SSH_COMMAND_EXECUTOR]
     *      --> user: user login for remote shell [default domotz]
     *      --> password: password to forward to ssh using domotz_sshpass
     *      --> host: target device [default localhost]
     *      --> ttl: lifetime of channel [default 1 hour]
     *      --> ... see OPTIONS_MAP
     * }
     */
    function exec(command, options) {
        var ssh, args = [];

        var logId = getOpt(options, ['log_prefix'], MODULE);
        var user = getOpt(options, ['user', 'username'], USER);
        var password = getOpt(options, ['password', 'pwd'], PASSWORD);
        var host = getOpt(options, ['host', 'hostname'], HOST);

        if (password) {
            console.verbose(logId + ' - Use sshpass to forward login password');
            ssh = SSHPASS_BINARY;
            args.push('-p');
            args.push(password);
            args.push(SSH_BINARY);
        } else {
            ssh = SSH_BINARY;
        }

        setDefault(options, 'user_known_host_file', USER_KNOWN_HOST_FILE);
        setDefault(options, 'host_key_checking', HOST_KEY_CHECKING);

        Object.keys(options).forEach(function (opt) {
            if (OPTIONS_MAP.hasOwnProperty(opt)) {
                var arg1 = OPTIONS_MAP[opt],
                    arg2 = options[opt];
                if (arg1.indexOf('-o') === 0) {
                    args.push(arg1 + arg2);
                } else if (typeof arg2 !== 'boolean') {
                    args.push(arg1);
                    args.push(arg2);
                } else {
                    args.push(arg1);
                }
                delete options[opt];
            }
        });

        args.push(user + '@' + host);

        if (command) {
            args.push(command);
        }

        options.env = getCleanEnv();

        return procUtils.spawn(ssh, args, options);

    }

    return {
        exec: exec
    };
};