JGitPasswordAuthentication.java

/*
 * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package org.eclipse.jgit.internal.transport.sshd;

import static org.apache.sshd.core.CoreModuleProperties.PASSWORD_PROMPTS;

import org.apache.sshd.client.auth.keyboard.UserInteraction;
import org.apache.sshd.client.auth.password.UserAuthPassword;
import org.apache.sshd.client.session.ClientSession;

/**
 * A password authentication handler that uses the {@link JGitUserInteraction}
 * to ask the user for the password. It also respects the
 * {@code NumberOfPasswordPrompts} ssh config.
 */
public class JGitPasswordAuthentication extends UserAuthPassword {

    private int maxAttempts;

    private int attempts;

    @Override
    public void init(ClientSession session, String service) throws Exception {
        super.init(session, service);
        maxAttempts = Math.max(1,
                PASSWORD_PROMPTS.getRequired(session).intValue());
        attempts = 0;
    }

    @Override
    protected boolean sendAuthDataRequest(ClientSession session, String service)
            throws Exception {
        if (++attempts > maxAttempts) {
            return false;
        }
        UserInteraction interaction = session.getUserInteraction();
        if (!interaction.isInteractionAllowed(session)) {
            return false;
        }
        String password = getPassword(session, interaction);
        if (password == null) {
            throw new AuthenticationCanceledException();
        }
        // sendPassword takes a buffer as first argument, but actually doesn't
        // use it and creates its own buffer...
        sendPassword(null, session, password, password);
        return true;
    }

    private String getPassword(ClientSession session,
            UserInteraction interaction) {
        String[] results = interaction.interactive(session, null, null, "", //$NON-NLS-1$
                new String[] { SshdText.get().passwordPrompt },
                new boolean[] { false });
        return (results == null || results.length == 0) ? null : results[0];
    }
}