org.eclipse.jgit.transport.OpenSshConfig.java Source code

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/*
 * Copyright (C) 2008, 2018, Google Inc.
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "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 COPYRIGHT OWNER OR
 * CONTRIBUTORS 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.
 */

package org.eclipse.jgit.transport;

import static org.eclipse.jgit.internal.transport.ssh.OpenSshConfigFile.positive;

import java.io.File;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

import org.eclipse.jgit.internal.transport.ssh.OpenSshConfigFile;
import org.eclipse.jgit.internal.transport.ssh.OpenSshConfigFile.HostEntry;
import org.eclipse.jgit.util.FS;

import com.jcraft.jsch.ConfigRepository;

/**
 * Fairly complete configuration parser for the OpenSSH ~/.ssh/config file.
 * <p>
 * JSch does have its own config file parser
 * {@link com.jcraft.jsch.OpenSSHConfig} since version 0.1.50, but it has a
 * number of problems:
 * <ul>
 * <li>it splits lines of the format "keyword = value" wrongly: you'd end up
 * with the value "= value".
 * <li>its "Host" keyword is not case insensitive.
 * <li>it doesn't handle quoted values.
 * <li>JSch's OpenSSHConfig doesn't monitor for config file changes.
 * </ul>
 * <p>
 * This parser makes the critical options available to
 * {@link org.eclipse.jgit.transport.SshSessionFactory} via
 * {@link org.eclipse.jgit.transport.OpenSshConfig.Host} objects returned by
 * {@link #lookup(String)}, and implements a fully conforming
 * {@link com.jcraft.jsch.ConfigRepository} providing
 * {@link com.jcraft.jsch.ConfigRepository.Config}s via
 * {@link #getConfig(String)}.
 * </p>
 *
 * @see OpenSshConfigFile
 */
public class OpenSshConfig implements ConfigRepository {

    /**
     * Obtain the user's configuration data.
     * <p>
     * The configuration file is always returned to the caller, even if no file
     * exists in the user's home directory at the time the call was made. Lookup
     * requests are cached and are automatically updated if the user modifies
     * the configuration file since the last time it was cached.
     *
     * @param fs
     *            the file system abstraction which will be necessary to
     *            perform certain file system operations.
     * @return a caching reader of the user's configuration file.
     */
    public static OpenSshConfig get(FS fs) {
        File home = fs.userHome();
        if (home == null)
            home = new File(".").getAbsoluteFile(); //$NON-NLS-1$

        final File config = new File(new File(home, SshConstants.SSH_DIR), SshConstants.CONFIG);
        return new OpenSshConfig(home, config);
    }

    /** The base file. */
    private OpenSshConfigFile configFile;

    OpenSshConfig(File h, File cfg) {
        configFile = new OpenSshConfigFile(h, cfg, SshSessionFactory.getLocalUserName());
    }

    /**
     * Locate the configuration for a specific host request.
     *
     * @param hostName
     *            the name the user has supplied to the SSH tool. This may be a
     *            real host name, or it may just be a "Host" block in the
     *            configuration file.
     * @return r configuration for the requested name. Never null.
     */
    public Host lookup(String hostName) {
        HostEntry entry = configFile.lookup(hostName, -1, null);
        return new Host(entry, hostName, configFile.getLocalUserName());
    }

    /**
     * Configuration of one "Host" block in the configuration file.
     * <p>
     * If returned from {@link OpenSshConfig#lookup(String)} some or all of the
     * properties may not be populated. The properties which are not populated
     * should be defaulted by the caller.
     * <p>
     * When returned from {@link OpenSshConfig#lookup(String)} any wildcard
     * entries which appear later in the configuration file will have been
     * already merged into this block.
     */
    public static class Host {
        String hostName;

        int port;

        File identityFile;

        String user;

        String preferredAuthentications;

        Boolean batchMode;

        String strictHostKeyChecking;

        int connectionAttempts;

        private HostEntry entry;

        private Config config;

        // See com.jcraft.jsch.OpenSSHConfig. Translates some command-line keys
        // to ssh-config keys.
        private static final Map<String, String> KEY_MAP = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);

        static {
            KEY_MAP.put("kex", SshConstants.KEX_ALGORITHMS); //$NON-NLS-1$
            KEY_MAP.put("server_host_key", SshConstants.HOST_KEY_ALGORITHMS); //$NON-NLS-1$
            KEY_MAP.put("cipher.c2s", SshConstants.CIPHERS); //$NON-NLS-1$
            KEY_MAP.put("cipher.s2c", SshConstants.CIPHERS); //$NON-NLS-1$
            KEY_MAP.put("mac.c2s", SshConstants.MACS); //$NON-NLS-1$
            KEY_MAP.put("mac.s2c", SshConstants.MACS); //$NON-NLS-1$
            KEY_MAP.put("compression.s2c", SshConstants.COMPRESSION); //$NON-NLS-1$
            KEY_MAP.put("compression.c2s", SshConstants.COMPRESSION); //$NON-NLS-1$
            KEY_MAP.put("compression_level", "CompressionLevel"); //$NON-NLS-1$ //$NON-NLS-2$
            KEY_MAP.put("MaxAuthTries", //$NON-NLS-1$
                    SshConstants.NUMBER_OF_PASSWORD_PROMPTS);
        }

        private static String mapKey(String key) {
            String k = KEY_MAP.get(key);
            return k != null ? k : key;
        }

        /**
         * Creates a new uninitialized {@link Host}.
         */
        public Host() {
            // For API backwards compatibility with pre-4.9 JGit
        }

        Host(HostEntry entry, String hostName, String localUserName) {
            this.entry = entry;
            complete(hostName, localUserName);
        }

        /**
         * @return the value StrictHostKeyChecking property, the valid values
         *         are "yes" (unknown hosts are not accepted), "no" (unknown
         *         hosts are always accepted), and "ask" (user should be asked
         *         before accepting the host)
         */
        public String getStrictHostKeyChecking() {
            return strictHostKeyChecking;
        }

        /**
         * @return the real IP address or host name to connect to; never null.
         */
        public String getHostName() {
            return hostName;
        }

        /**
         * @return the real port number to connect to; never 0.
         */
        public int getPort() {
            return port;
        }

        /**
         * @return path of the private key file to use for authentication; null
         *         if the caller should use default authentication strategies.
         */
        public File getIdentityFile() {
            return identityFile;
        }

        /**
         * @return the real user name to connect as; never null.
         */
        public String getUser() {
            return user;
        }

        /**
         * @return the preferred authentication methods, separated by commas if
         *         more than one authentication method is preferred.
         */
        public String getPreferredAuthentications() {
            return preferredAuthentications;
        }

        /**
         * @return true if batch (non-interactive) mode is preferred for this
         *         host connection.
         */
        public boolean isBatchMode() {
            return batchMode != null && batchMode.booleanValue();
        }

        /**
         * @return the number of tries (one per second) to connect before
         *         exiting. The argument must be an integer. This may be useful
         *         in scripts if the connection sometimes fails. The default is
         *         1.
         * @since 3.4
         */
        public int getConnectionAttempts() {
            return connectionAttempts;
        }

        private void complete(String initialHostName, String localUserName) {
            // Try to set values from the options.
            hostName = entry.getValue(SshConstants.HOST_NAME);
            user = entry.getValue(SshConstants.USER);
            port = positive(entry.getValue(SshConstants.PORT));
            connectionAttempts = positive(entry.getValue(SshConstants.CONNECTION_ATTEMPTS));
            strictHostKeyChecking = entry.getValue(SshConstants.STRICT_HOST_KEY_CHECKING);
            batchMode = Boolean.valueOf(OpenSshConfigFile.flag(entry.getValue(SshConstants.BATCH_MODE)));
            preferredAuthentications = entry.getValue(SshConstants.PREFERRED_AUTHENTICATIONS);
            // Fill in defaults if still not set
            if (hostName == null || hostName.isEmpty()) {
                hostName = initialHostName;
            }
            if (user == null || user.isEmpty()) {
                user = localUserName;
            }
            if (port <= 0) {
                port = SshConstants.SSH_DEFAULT_PORT;
            }
            if (connectionAttempts <= 0) {
                connectionAttempts = 1;
            }
            List<String> identityFiles = entry.getValues(SshConstants.IDENTITY_FILE);
            if (identityFiles != null && !identityFiles.isEmpty()) {
                identityFile = new File(identityFiles.get(0));
            }
        }

        Config getConfig() {
            if (config == null) {
                config = new Config() {

                    @Override
                    public String getHostname() {
                        return Host.this.getHostName();
                    }

                    @Override
                    public String getUser() {
                        return Host.this.getUser();
                    }

                    @Override
                    public int getPort() {
                        return Host.this.getPort();
                    }

                    @Override
                    public String getValue(String key) {
                        // See com.jcraft.jsch.OpenSSHConfig.MyConfig.getValue()
                        // for this special case.
                        if (key.equals("compression.s2c") //$NON-NLS-1$
                                || key.equals("compression.c2s")) { //$NON-NLS-1$
                            if (!OpenSshConfigFile.flag(Host.this.entry.getValue(mapKey(key)))) {
                                return "none,zlib@openssh.com,zlib"; //$NON-NLS-1$
                            }
                            return "zlib@openssh.com,zlib,none"; //$NON-NLS-1$
                        }
                        return Host.this.entry.getValue(mapKey(key));
                    }

                    @Override
                    public String[] getValues(String key) {
                        List<String> values = Host.this.entry.getValues(mapKey(key));
                        if (values == null) {
                            return new String[0];
                        }
                        return values.toArray(new String[0]);
                    }
                };
            }
            return config;
        }

        @Override
        @SuppressWarnings("nls")
        public String toString() {
            return "Host [hostName=" + hostName + ", port=" + port + ", identityFile=" + identityFile + ", user="
                    + user + ", preferredAuthentications=" + preferredAuthentications + ", batchMode=" + batchMode
                    + ", strictHostKeyChecking=" + strictHostKeyChecking + ", connectionAttempts="
                    + connectionAttempts + ", entry=" + entry + "]";
        }
    }

    /**
     * {@inheritDoc}
     * <p>
     * Retrieves the full {@link com.jcraft.jsch.ConfigRepository.Config Config}
     * for the given host name. Should be called only by Jsch and tests.
     *
     * @since 4.9
     */
    @Override
    public Config getConfig(String hostName) {
        Host host = lookup(hostName);
        return host.getConfig();
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        return "OpenSshConfig [configFile=" + configFile + ']'; //$NON-NLS-1$
    }
}