de.schlichtherle.truezip.key.pbe.console.ConsoleSafePbeParametersView Maven / Gradle / Ivy

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/*
 * Copyright (C) 2005-2015 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package de.schlichtherle.truezip.key.pbe.console;

import de.schlichtherle.truezip.crypto.param.KeyStrength;
import de.schlichtherle.truezip.key.KeyPromptingDisabledException;
import de.schlichtherle.truezip.key.PromptingKeyProvider.Controller;
import de.schlichtherle.truezip.key.pbe.SafePbeParameters;
import de.schlichtherle.truezip.key.pbe.SafePbeParametersView;
import java.io.Console;
import java.io.PrintWriter;
import java.net.URI;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.ResourceBundle;
import javax.annotation.concurrent.ThreadSafe;

/**
 * A console based user interface to prompt for passwords.
 * 
 * @author  Christian Schlichtherle
 */
@ThreadSafe
public abstract class ConsoleSafePbeParametersView<
        S extends KeyStrength,
        P extends SafePbeParameters>
extends SafePbeParametersView {

    private static final ResourceBundle
            resources = ResourceBundle.getBundle(
                ConsoleSafePbeParametersView.class.getName());

    /**
     * Used to lock out prompting by multiple threads.
     */
    private static final PromptingLock lock = new PromptingLock();

    /** The minimum acceptable length of a password. */
    private static final int MIN_PASSWD_LEN = 8;

    /**
     * The last resource ID used when prompting.
     * Initialized to the empty string.
     */
    @edu.umd.cs.findbugs.annotations.SuppressWarnings("ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD")
    private static URI lastResource = URI.create(""); // NOI18N
    
    private static final String YES = resources.getString("yes");
    private static final String NO = resources.getString("no");

    @Override
    public final void promptWriteKey(final Controller
 controller)
    throws KeyPromptingDisabledException {
        final Console con = System.console();
        if (null == con)
            throw new KeyPromptingDisabledException();

        synchronized (lock) {
            final URI resource = controller.getResource();
            assert null != resource;
            if (!lastResource.equals(resource))
                con.printf(resources.getString("writeKey.banner"), resource);
            lastResource = resource;

            P param = controller.getKey();
            if (null == param)
                param = newPbeParameters();

            while (true) {
                char[] input1 = con.readPassword(
                        resources.getString("writeKey.newPasswd1"));
                if (null == input1 || 0 >= input1.length)
                    return;
                if (MIN_PASSWD_LEN > input1.length) {
                    con.printf(resources.getString("writeKey.passwd.tooShort"), MIN_PASSWD_LEN);
                    continue;
                }
                try {
                    char[] input2 = con.readPassword(
                            resources.getString("writeKey.newPasswd2"));
                    if (input2 == null)
                        return;
                    try {
                        if (!Arrays.equals(input1, input2)) {
                            con.printf(resources.getString("writeKey.passwd.noMatch"));
                            continue;
                        }
                        param.setPassword(input1);
                        break;
                    } finally {
                        Arrays.fill(input2, (char) 0);
                    }
                }  finally {
                    Arrays.fill(input1, (char) 0);
                }
            }

            con.printf(resources.getString("keyStrength.banner"));
            final String selection;
            final Map map;
            {
                final StringBuilder builder = new StringBuilder();
                final S[] array = param.getKeyStrengthValues();
                map = new HashMap(array.length / 3 * 4 + 1);
                final PrintWriter writer = con.writer();
                for (final S strength : array) {
                    if (0 < builder.length())
                        builder.append('/');
                    builder.append(strength.getBits());
                    map.put(strength.getBits(), strength);
                    writer.println(strength);
                }
                selection = builder.toString();
            }

            while (true) {
                String input = con.readLine(
                        resources.getString("keyStrength.prompt"),
                        selection,
                        param.getKeyStrength().getBits());
                if (null == input || input.length() <= 0)
                    break;
                try {
                    final int bits = Integer.parseInt(input);
                    final S strength = map.get(bits);
                    if (null != strength) {
                        assert strength.getBits() == bits;
                        param.setKeyStrength(strength);
                        break;
                    }
                } catch (NumberFormatException ex) {
                }
            }

            controller.setKey(param);
        }
    }

    @Override
    public void promptReadKey(
            final Controller controller,
            final boolean invalid)
    throws KeyPromptingDisabledException {
        final Console con = System.console();
        if (null == con)
            throw new KeyPromptingDisabledException();

        synchronized (lock) {
            if (invalid)
                con.printf(resources.getString("readKey.invalid"));

            final URI resource = controller.getResource();
            assert null != resource;
            if (!lastResource.equals(resource))
                con.printf(resources.getString("readKey.banner"), resource);
            lastResource = resource;

            final char[] passwd = con.readPassword(resources.getString("readKey.passwd"));
            if (null == passwd || passwd.length <= 0) {
                controller.setKey(null);
                return;
            }

            final P param = newPbeParameters();
            param.setPassword(passwd);
            Arrays.fill(passwd, (char) 0);
            controller.setKey(param);

            while (true) {
                String changeKey = con.readLine(resources.getString("readKey.change"));
                controller.setChangeRequested(YES.equalsIgnoreCase(changeKey));
                if (       null == changeKey
                        || changeKey.length() <= 0
                        || YES.equalsIgnoreCase(changeKey)
                        || NO.equalsIgnoreCase(changeKey))
                    return;
            }
        }
    }

    /** Used to lock out concurrent prompting. */
    private static class PromptingLock {
    }
}