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disable dtd processing 

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1837850 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
PJ Fanning 2018-08-11 09:22:05 +00:00
parent 8576537693
commit d896bb9e30
5 changed files with 96 additions and 12 deletions
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9
src/ooxml/java/org/apache/poi/ooxml/util/DocumentHelper.java
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@ -95,11 +95,14 @@ public final class DocumentHelper {
}
}
private static final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
static final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
static {
documentBuilderFactory.setNamespaceAware(true);
documentBuilderFactory.setValidating(false);
trySetSAXFeature(documentBuilderFactory, XMLConstants.FEATURE_SECURE_PROCESSING, true);
trySetSAXFeature(documentBuilderFactory, POIXMLConstants.FEATURE_LOAD_DTD_GRAMMAR, false);
trySetSAXFeature(documentBuilderFactory, POIXMLConstants.FEATURE_LOAD_EXTERNAL_DTD, false);
trySetXercesSecurityManager(documentBuilderFactory);
}
@ -123,7 +126,7 @@ public final class DocumentHelper {
Object mgr = Class.forName(securityManagerClassName).newInstance();
Method setLimit = mgr.getClass().getMethod("setEntityExpansionLimit", Integer.TYPE);
setLimit.invoke(mgr, 4096);
dbf.setAttribute("http://apache.org/xml/properties/security-manager", mgr);
dbf.setAttribute(POIXMLConstants.PROPERTY_SECURITY_MANAGER, mgr);
// Stop once one can be setup without error
return;
} catch (ClassNotFoundException e) {
@ -134,7 +137,7 @@ public final class DocumentHelper {
}
// separate old version of Xerces not found => use the builtin way of setting the property
dbf.setAttribute("http://www.oracle.com/xml/jaxp/properties/entityExpansionLimit", 4096);
dbf.setAttribute(POIXMLConstants.PROPERTY_ENTITY_EXPANSION_LIMIT, 4096);
}
/**

25
src/ooxml/java/org/apache/poi/ooxml/util/POIXMLConstants.java Normal file
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@ -0,0 +1,25 @@
/* ====================================================================
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.poi.ooxml.util;
public class POIXMLConstants {
public static final String FEATURE_LOAD_DTD_GRAMMAR = "http://apache.org/xml/features/nonvalidating/load-dtd-grammar";
public static final String FEATURE_LOAD_EXTERNAL_DTD = "http://apache.org/xml/features/nonvalidating/load-external-dtd";
public static final String PROPERTY_ENTITY_EXPANSION_LIMIT = "http://www.oracle.com/xml/jaxp/properties/entityExpansionLimit";
public static final String PROPERTY_SECURITY_MANAGER = "http://apache.org/xml/properties/security-manager";
}

17
src/ooxml/java/org/apache/poi/ooxml/util/SAXHelper.java
View File

@ -68,6 +68,9 @@ public final class SAXHelper {
saxFactory = SAXParserFactory.newInstance();
saxFactory.setValidating(false);
saxFactory.setNamespaceAware(true);
trySetSAXFeature(saxFactory, XMLConstants.FEATURE_SECURE_PROCESSING, true);
trySetSAXFeature(saxFactory, POIXMLConstants.FEATURE_LOAD_DTD_GRAMMAR, false);
trySetSAXFeature(saxFactory, POIXMLConstants.FEATURE_LOAD_EXTERNAL_DTD, false);
} catch (RuntimeException | Error re) { // NOSONAR
// this also catches NoClassDefFoundError, which may be due to a local class path issue
// This may occur if the code is run inside a web container
@ -81,6 +84,16 @@ public final class SAXHelper {
}
}
private static void trySetSAXFeature(SAXParserFactory spf, String feature, boolean flag) {
try {
spf.setFeature(feature, flag);
} catch (Exception e) {
logger.log(POILogger.WARN, "SAX Feature unsupported", feature, e);
} catch (AbstractMethodError ame) {
logger.log(POILogger.WARN, "Cannot set SAX feature because outdated XML parser in classpath", feature, ame);
}
}
private static void trySetSAXFeature(XMLReader xmlReader, String feature) {
try {
xmlReader.setFeature(feature, true);
@ -101,7 +114,7 @@ public final class SAXHelper {
Object mgr = Class.forName(securityManagerClassName).newInstance();
Method setLimit = mgr.getClass().getMethod("setEntityExpansionLimit", Integer.TYPE);
setLimit.invoke(mgr, 4096);
xmlReader.setProperty("http://apache.org/xml/properties/security-manager", mgr);
xmlReader.setProperty(POIXMLConstants.PROPERTY_SECURITY_MANAGER, mgr);
// Stop once one can be setup without error
return;
} catch (ClassNotFoundException e) {
@ -117,7 +130,7 @@ public final class SAXHelper {
// separate old version of Xerces not found => use the builtin way of setting the property
try {
xmlReader.setProperty("http://www.oracle.com/xml/jaxp/properties/entityExpansionLimit", 4096);
xmlReader.setProperty(POIXMLConstants.PROPERTY_ENTITY_EXPANSION_LIMIT, 4096);
} catch (SAXException e) { // NOSONAR - also catch things like NoClassDefError here
// throttle the log somewhat as it can spam the log otherwise
if(System.currentTimeMillis() > lastLog + TimeUnit.MINUTES.toMillis(5)) {

44
src/ooxml/testcases/org/apache/poi/ooxml/util/TestDocumentHelper.java Normal file
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@ -0,0 +1,44 @@
/* ====================================================================
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.poi.ooxml.util;
import org.junit.Test;
import org.xml.sax.InputSource;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import java.io.ByteArrayInputStream;
import static org.junit.Assert.*;
public class TestDocumentHelper {
@Test
public void testDocumentBuilder() throws Exception {
DocumentBuilder documentBuilder = DocumentHelper.newDocumentBuilder();
assertNotSame(documentBuilder, DocumentHelper.newDocumentBuilder());
assertTrue(documentBuilder.isNamespaceAware());
assertFalse(documentBuilder.isValidating());
documentBuilder.parse(new InputSource(new ByteArrayInputStream("<xml></xml>".getBytes("UTF-8"))));
}
@Test
public void testDocumentBuilderFactory() throws Exception {
assertTrue(DocumentHelper.documentBuilderFactory.getFeature(XMLConstants.FEATURE_SECURE_PROCESSING));
assertFalse(DocumentHelper.documentBuilderFactory.getFeature(POIXMLConstants.FEATURE_LOAD_DTD_GRAMMAR));
assertFalse(DocumentHelper.documentBuilderFactory.getFeature(POIXMLConstants.FEATURE_LOAD_EXTERNAL_DTD));
}
}

13
src/ooxml/testcases/org/apache/poi/ooxml/util/TestSAXHelper.java
View File

@ -16,10 +16,7 @@
==================================================================== */
package org.apache.poi.ooxml.util;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.*;
import java.io.ByteArrayInputStream;
@ -35,10 +32,12 @@ public class TestSAXHelper {
XMLReader reader = SAXHelper.newXMLReader();
assertNotSame(reader, SAXHelper.newXMLReader());
assertTrue(reader.getFeature(XMLConstants.FEATURE_SECURE_PROCESSING));
assertFalse(reader.getFeature(POIXMLConstants.FEATURE_LOAD_DTD_GRAMMAR));
assertFalse(reader.getFeature(POIXMLConstants.FEATURE_LOAD_EXTERNAL_DTD));
assertEquals(SAXHelper.IGNORING_ENTITY_RESOLVER, reader.getEntityResolver());
assertNotNull(reader.getProperty("http://www.oracle.com/xml/jaxp/properties/entityExpansionLimit"));
assertEquals("4096", reader.getProperty("http://www.oracle.com/xml/jaxp/properties/entityExpansionLimit"));
assertNotNull(reader.getProperty("http://apache.org/xml/properties/security-manager"));
assertNotNull(reader.getProperty(POIXMLConstants.PROPERTY_ENTITY_EXPANSION_LIMIT));
assertEquals("4096", reader.getProperty(POIXMLConstants.PROPERTY_ENTITY_EXPANSION_LIMIT));
assertNotNull(reader.getProperty(POIXMLConstants.PROPERTY_SECURITY_MANAGER));
reader.parse(new InputSource(new ByteArrayInputStream("<xml></xml>".getBytes("UTF-8"))));
}