104 lines
2.7 KiB
Java
104 lines
2.7 KiB
Java
/*
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* Copyright 2018 Paul Schaub.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.pgpainless.util;
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import javax.annotation.Nullable;
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import java.util.Arrays;
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public class Passphrase {
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private final Object lock = new Object();
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private final char[] chars;
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private boolean valid = true;
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/**
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* Passphrase for keys etc.
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*
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* @param chars may be null for empty passwords.
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*/
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public Passphrase(@Nullable char[] chars) {
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this.chars = chars;
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}
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/**
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* Overwrite the char array with spaces and mark the {@link Passphrase} as invalidated.
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*/
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public void clear() {
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synchronized (lock) {
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if (chars != null) {
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Arrays.fill(chars, ' ');
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}
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valid = false;
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}
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}
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/**
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* Call {@link #clear()} to make sure the memory is overwritten.
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*
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* @throws Throwable bad things might happen in {@link Object#finalize()}.
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*/
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@Override
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protected void finalize() throws Throwable {
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clear();
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super.finalize();
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}
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/**
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* Return a copy of the underlying char array.
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* A return value of {@code null} represents no password.
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*
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* @return passphrase chars.
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*
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* @throws IllegalStateException in case the password has been cleared at this point.
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*/
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public @Nullable char[] getChars() {
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synchronized (lock) {
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if (!valid) {
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throw new IllegalStateException("Passphrase has been cleared.");
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}
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if (chars == null) {
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return null;
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}
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char[] copy = new char[chars.length];
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System.arraycopy(chars, 0, copy, 0, chars.length);
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return copy;
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}
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}
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/**
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* Return true if the passphrase has not yet been cleared.
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*
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* @return valid
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*/
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public boolean isValid() {
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synchronized (lock) {
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return valid;
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}
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}
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/**
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* Represents a {@link Passphrase} instance that represents no password.
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*
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* @return empty passphrase
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*/
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public static Passphrase emptyPassphrase() {
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return new Passphrase(null);
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}
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}
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