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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.commons.io.serialization;

import java.io.IOException;
import java.io.InputStream;
import java.io.InvalidClassException;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

An ObjectInputStream that's restricted to deserialize
a limited set of classes.

Various accept/reject methods allow for specifying which classes
can be deserialized.


Design inspired by IBM
DeveloperWorks Article.

/**
 * An <code>ObjectInputStream</code> that's restricted to deserialize
 * a limited set of classes.
 *
 * <p>
 * Various accept/reject methods allow for specifying which classes
 * can be deserialized.
 * </p>
 *
 * <p>
 * Design inspired by <a
 * href="http://www.ibm.com/developerworks/library/se-lookahead/">IBM
 * DeveloperWorks Article</a>.
 * </p>
 */
public class ValidatingObjectInputStream extends ObjectInputStream {
    private final List<ClassNameMatcher> acceptMatchers = new ArrayList<>();
    private final List<ClassNameMatcher> rejectMatchers = new ArrayList<>();

    
Constructs an object to deserialize the specified input stream.
At least one accept method needs to be called to specify which
classes can be deserialized, as by default no classes are
accepted.
Params:
input – an input stream
Throws:
IOException – if an I/O error occurs while reading stream header/**
     * Constructs an object to deserialize the specified input stream.
     * At least one accept method needs to be called to specify which
     * classes can be deserialized, as by default no classes are
     * accepted.
     *
     * @param input an input stream
     * @throws IOException if an I/O error occurs while reading stream header
     */
    public ValidatingObjectInputStream(final InputStream input) throws IOException {
        super(input);
    }

    
Check that the classname conforms to requirements.
Params:
name – The class name
Throws:
InvalidClassException – when a non-accepted class is encountered/** Check that the classname conforms to requirements.
     * @param name The class name
     * @throws InvalidClassException when a non-accepted class is encountered
     */
    private void validateClassName(final String name) throws InvalidClassException {
        // Reject has precedence over accept
        for (final ClassNameMatcher m : rejectMatchers) {
            if (m.matches(name)) {
                invalidClassNameFound(name);
            }
        }

        boolean ok = false;
        for (final ClassNameMatcher m : acceptMatchers) {
            if (m.matches(name)) {
                ok = true;
                break;
            }
        }
        if (!ok) {
            invalidClassNameFound(name);
        }
    }

    
Called to throw InvalidClassException if an invalid
class name is found during deserialization. Can be overridden, for example
to log those class names.
Params:
className – name of the invalid class
Throws:
InvalidClassException – if the specified class is not allowed/**
     * Called to throw <code>InvalidClassException</code> if an invalid
     * class name is found during deserialization. Can be overridden, for example
     * to log those class names.
     *
     * @param className name of the invalid class
     * @throws InvalidClassException if the specified class is not allowed
     */
    protected void invalidClassNameFound(final String className) throws InvalidClassException {
        throw new InvalidClassException("Class name not accepted: " + className);
    }

    @Override
    protected Class<?> resolveClass(final ObjectStreamClass osc) throws IOException, ClassNotFoundException {
        validateClassName(osc.getName());
        return super.resolveClass(osc);
    }

    
Accept the specified classes for deserialization, unless they
are otherwise rejected.
Params:
classes – Classes to accept
Returns:
this object/**
     * Accept the specified classes for deserialization, unless they
     * are otherwise rejected.
     *
     * @param classes Classes to accept
     * @return this object
     */
    public ValidatingObjectInputStream accept(final Class<?>... classes) {
        for (final Class<?> c : classes) {
            acceptMatchers.add(new FullClassNameMatcher(c.getName()));
        }
        return this;
    }

    
Reject the specified classes for deserialization, even if they
are otherwise accepted.
Params:
classes – Classes to reject
Returns:
this object/**
     * Reject the specified classes for deserialization, even if they
     * are otherwise accepted.
     *
     * @param classes Classes to reject
     * @return this object
     */
    public ValidatingObjectInputStream reject(final Class<?>... classes) {
        for (final Class<?> c : classes) {
            rejectMatchers.add(new FullClassNameMatcher(c.getName()));
        }
        return this;
    }

    
Accept the wildcard specified classes for deserialization,
unless they are otherwise rejected.
Params:
patterns – Wildcard filename patterns as defined by FilenameUtils.wildcardMatch
Returns:
this object/**
     * Accept the wildcard specified classes for deserialization,
     * unless they are otherwise rejected.
     *
     * @param patterns Wildcard filename patterns as defined by
     *                  {@link org.apache.commons.io.FilenameUtils#wildcardMatch(String, String) FilenameUtils.wildcardMatch}
     * @return this object
     */
    public ValidatingObjectInputStream accept(final String... patterns) {
        for (final String pattern : patterns) {
            acceptMatchers.add(new WildcardClassNameMatcher(pattern));
        }
        return this;
    }

    
Reject the wildcard specified classes for deserialization,
even if they are otherwise accepted.
Params:
patterns – Wildcard filename patterns as defined by FilenameUtils.wildcardMatch
Returns:
this object/**
     * Reject the wildcard specified classes for deserialization,
     * even if they are otherwise accepted.
     *
     * @param patterns Wildcard filename patterns as defined by
     *                  {@link org.apache.commons.io.FilenameUtils#wildcardMatch(String, String) FilenameUtils.wildcardMatch}
     * @return this object
     */
    public ValidatingObjectInputStream reject(final String... patterns) {
        for (final String pattern : patterns) {
            rejectMatchers.add(new WildcardClassNameMatcher(pattern));
        }
        return this;
    }

    
Accept class names that match the supplied pattern for
deserialization, unless they are otherwise rejected.
Params:
pattern – standard Java regexp
Returns:
this object/**
     * Accept class names that match the supplied pattern for
     * deserialization, unless they are otherwise rejected.
     *
     * @param pattern standard Java regexp
     * @return this object
     */
    public ValidatingObjectInputStream accept(final Pattern pattern) {
        acceptMatchers.add(new RegexpClassNameMatcher(pattern));
        return this;
    }

    
Reject class names that match the supplied pattern for
deserialization, even if they are otherwise accepted.
Params:
pattern – standard Java regexp
Returns:
this object/**
     * Reject class names that match the supplied pattern for
     * deserialization, even if they are otherwise accepted.
     *
     * @param pattern standard Java regexp
     * @return this object
     */
    public ValidatingObjectInputStream reject(final Pattern pattern) {
        rejectMatchers.add(new RegexpClassNameMatcher(pattern));
        return this;
    }

    
Accept class names where the supplied ClassNameMatcher matches for
deserialization, unless they are otherwise rejected.
Params:
m – the matcher to use
Returns:
this object/**
     * Accept class names where the supplied ClassNameMatcher matches for
     * deserialization, unless they are otherwise rejected.
     *
     * @param m the matcher to use
     * @return this object
     */
    public ValidatingObjectInputStream accept(final ClassNameMatcher m) {
        acceptMatchers.add(m);
        return this;
    }

    
Reject class names where the supplied ClassNameMatcher matches for
deserialization, even if they are otherwise accepted.
Params:
m – the matcher to use
Returns:
this object/**
     * Reject class names where the supplied ClassNameMatcher matches for
     * deserialization, even if they are otherwise accepted.
     *
     * @param m the matcher to use
     * @return this object
     */
    public ValidatingObjectInputStream reject(final ClassNameMatcher m) {
        rejectMatchers.add(m);
        return this;
    }
}