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Code Issues Releases Wiki Activity

VCardProvider should use a safe parser

Browse source 
Where e.g. entity reference expansion is disbled. Note that this affects
only the VCard provider, as it's the only provider in Smack that uses
SAX's DocumentBuilder.

Fixes SMACK-620
This commit is contained in:
Florian Schmaus 2014-12-14 13:27:59 +01:00
parent b5c9bb2611
commit ff2c71e042
1 changed files with 48 additions and 2 deletions
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50
smack-extensions/src/main/java/org/jivesoftware/smackx/vcardtemp/provider/VCardProvider.java
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@ -29,6 +29,7 @@ import org.xml.sax.SAXException;
import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException; import org.xmlpull.v1.XmlPullParserException;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException; import javax.xml.parsers.ParserConfigurationException;
@ -52,6 +53,52 @@ public class VCardProvider extends IQProvider<VCard> {
private static final String PREFERRED_ENCODING = "UTF-8"; private static final String PREFERRED_ENCODING = "UTF-8";
private static final DocumentBuilderFactory DOCUMENT_BUILDER_FACTORY;
static {
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
try {
documentBuilderFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
} catch (ParserConfigurationException e) {
LOGGER.log(Level.FINER, "Could not disallow doctype decl", e);
// If we can't disable DTDs, then at least try the following
// Xerces 1 - http://xerces.apache.org/xerces-j/features.html#external-general-entities
// Xerces 2 - http://xerces.apache.org/xerces2-j/features.html#external-general-entities
try {
documentBuilderFactory.setFeature( "http://xml.org/sax/features/external-general-entities", false);
documentBuilderFactory.setFeature( "http://xml.org/sax/features/external-parameter-entities", false);
} catch (ParserConfigurationException e1) {
LOGGER.log(Level.FINER, "Could not disallow external entities for xerces parser", e1);
}
}
// Android throws an UnsupportedOperationException when calling setXIncludeAware() and for some dumb reason also
// when calling isXIncludeWare(), while it defaults according to the docs to 'false'.
boolean isXIncludeAware;
try {
isXIncludeAware = documentBuilderFactory.isXIncludeAware();
} catch (UnsupportedOperationException e) {
// Assume we are on Android where isXIncludeAware defaults to 'false'
isXIncludeAware = false;
}
if (isXIncludeAware) {
documentBuilderFactory.setXIncludeAware(false);
}
documentBuilderFactory.setExpandEntityReferences(false);
// Harden the parser even further
documentBuilderFactory.setIgnoringComments(true);
documentBuilderFactory.setCoalescing(false);
documentBuilderFactory.setValidating(false);
try {
documentBuilderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
} catch (ParserConfigurationException e) {
LOGGER.log(Level.INFO, "Could not enable secure processing parsing feature", e);
}
DOCUMENT_BUILDER_FACTORY = documentBuilderFactory;
}
@Override @Override
public VCard parse(XmlPullParser parser, int initialDepth) throws XmlPullParserException, IOException, SmackException { public VCard parse(XmlPullParser parser, int initialDepth) throws XmlPullParserException, IOException, SmackException {
final StringBuilder sb = new StringBuilder(); final StringBuilder sb = new StringBuilder();
@ -106,8 +153,7 @@ public class VCardProvider extends IQProvider<VCard> {
public static VCard createVCardFromXML(String xml) throws UnsupportedEncodingException, SAXException, IOException, ParserConfigurationException { public static VCard createVCardFromXML(String xml) throws UnsupportedEncodingException, SAXException, IOException, ParserConfigurationException {
VCard vCard = new VCard(); VCard vCard = new VCard();
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder documentBuilder = DOCUMENT_BUILDER_FACTORY.newDocumentBuilder();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse( Document document = documentBuilder.parse(
new ByteArrayInputStream(xml.getBytes(PREFERRED_ENCODING))); new ByteArrayInputStream(xml.getBytes(PREFERRED_ENCODING)));