KeyPasswordProvider.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.transport.sshd;

import java.io.IOException;
import java.security.GeneralSecurityException;

import org.eclipse.jgit.transport.URIish;

/**
 * A {@code KeyPasswordProvider} provides passwords for encrypted private keys.
 *
 * @since 5.2
 */
public interface KeyPasswordProvider {

    /**
     * Obtains a passphrase to use to decrypt an ecrypted private key. Returning
     * {@code null} or an empty array will skip this key. To cancel completely,
     * the operation should raise
     * {@link java.util.concurrent.CancellationException}.
     *
     * @param uri
     *            identifying the key resource that is being attempted to be
     *            loaded
     * @param attempt
     *            the number of previous attempts to get a passphrase; &gt;= 0
     * @return the passphrase
     * @throws IOException
     *             if no password can be obtained
     */
    char[] getPassphrase(URIish uri, int attempt) throws IOException;

    /**
     * Define the maximum number of attempts to get a passphrase that should be
     * attempted for one identity resource through this provider.
     *
     * @param maxNumberOfAttempts
     *            number of times to ask for a passphrase;
     *            {@link IllegalArgumentException} may be thrown if &lt;= 0
     */
    void setAttempts(int maxNumberOfAttempts);

    /**
     * Gets the maximum number of attempts to get a passphrase that should be
     * attempted for one identity resource through this provider. The default
     * return 1.
     *
     * @return the number of times to ask for a passphrase; should be &gt;= 1.
     */
    default int getAttempts() {
        return 1;
    }

    /**
     * Invoked after a key has been loaded. If this raises an exception, the
     * original {@code error} is lost unless it is attached to that exception.
     *
     * @param uri
     *            identifying the key resource the key was attempted to be
     *            loaded from
     * @param attempt
     *            the number of times {@link #getPassphrase(URIish, int)} had
     *            been called; zero indicates that {@code uri} refers to a
     *            non-encrypted key
     * @param error
     *            {@code null} if the key was loaded successfully; otherwise an
     *            exception indicating why the key could not be loaded
     * @return {@code true} to re-try again; {@code false} to re-raise the
     *         {@code error} exception; Ignored if the key was loaded
     *         successfully, i.e., if {@code error == null}.
     * @throws IOException
     * @throws GeneralSecurityException
     */
    boolean keyLoaded(URIish uri, int attempt, Exception error)
            throws IOException, GeneralSecurityException;
}