org.wildfly.common.xml.XMLReaderFactoryUtil Maven / Gradle / Ivy

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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2022 Red Hat, Inc.
 *
 * Licensed 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.wildfly.common.xml;

import static org.wildfly.common.xml.FactoryConstants.APACHE_DISALLOW_DOCTYPE_DECL;
import static org.wildfly.common.xml.FactoryConstants.APACHE_LOAD_EXTERNAL_DTD;
import static org.wildfly.common.xml.FactoryConstants.XML_EXTERNAL_GENERAL_ENTITIES;
import static org.wildfly.common.xml.FactoryConstants.XML_EXTERNAL_PARAMETER_ENTITIES;
import static org.wildfly.common.xml.Log.XML_FACTORY_LOGGER;

import org.wildfly.common.annotation.NotNull;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Factory provides {@link XMLReaderFactory} with secure defaults set. Properties not supported generate a warning, but the
 * factory process creation will continue and return a result.
 * Settings based on recommendations of
 * Sonarcloud RSPEC-2755 and
 * OWASP XML
 * External Entity Prevention Cheatsheet.
 * 
 *
 * 

 * {@link org.wildfly.common.xml.FactoryConstants#APACHE_DISALLOW_DOCTYPE_DECL} is set to true.
 * {@link org.wildfly.common.xml.FactoryConstants#APACHE_LOAD_EXTERNAL_DTD} is set to false.
 * {@link org.wildfly.common.xml.FactoryConstants#XML_EXTERNAL_GENERAL_ENTITIES} is set to false.
 * {@link org.wildfly.common.xml.FactoryConstants#XML_EXTERNAL_PARAMETER_ENTITIES} is set to false.
 * 
 *
 * @author Boris Unckel
 * @since 1.6.0.Final
 */
public final class XMLReaderFactoryUtil {

    /*
     * Prevent recurring log messages (per classloader).
     */
    private static final AtomicBoolean TO_BE_LOGGED = new AtomicBoolean(true);

    /**
     * Factory generated with secure defaults.
     * @return an instance of the XMLInputFactory.
     */
    @NotNull
    public static XMLReader create() throws SAXException {
        final XMLReader instance = XMLReaderFactory.createXMLReader();
        final boolean toBeLogged = TO_BE_LOGGED.compareAndSet(true, false);

        try {
            instance.setFeature(APACHE_DISALLOW_DOCTYPE_DECL, true);
        } catch (SAXNotRecognizedException | SAXNotSupportedException e) {
            if (toBeLogged) {
                XML_FACTORY_LOGGER.xmlFactoryPropertyNotSupported(e, APACHE_DISALLOW_DOCTYPE_DECL,
                        instance.getClass().getCanonicalName());
            }
        }

        try {
            instance.setFeature(APACHE_LOAD_EXTERNAL_DTD, false);
        } catch (SAXNotRecognizedException | SAXNotSupportedException e) {
            if (toBeLogged) {
                XML_FACTORY_LOGGER.xmlFactoryPropertyNotSupported(e, APACHE_LOAD_EXTERNAL_DTD,
                        instance.getClass().getCanonicalName());
            }
        }

        try {
            instance.setFeature(XML_EXTERNAL_GENERAL_ENTITIES, false);
        } catch (SAXNotRecognizedException | SAXNotSupportedException e) {
            if (toBeLogged) {
                XML_FACTORY_LOGGER.xmlFactoryPropertyNotSupported(e, XML_EXTERNAL_GENERAL_ENTITIES,
                        instance.getClass().getCanonicalName());
            }
        }

        try {
            instance.setFeature(XML_EXTERNAL_PARAMETER_ENTITIES, false);
        } catch (SAXNotRecognizedException | SAXNotSupportedException e) {
            if (toBeLogged) {
                XML_FACTORY_LOGGER.xmlFactoryPropertyNotSupported(e, XML_EXTERNAL_PARAMETER_ENTITIES,
                        instance.getClass().getCanonicalName());
            }
        }

        return instance;
    }

    /**
     * No instance.
     */
    private XMLReaderFactoryUtil() {
        throw new IllegalStateException("No instance");
    }

}