/**
* 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.xml.security.utils.resolver.implementations;
import org.apache.xml.security.signature.XMLSignatureInput;
import org.apache.xml.security.utils.XMLUtils;
import org.apache.xml.security.utils.resolver.ResourceResolverException;
import org.apache.xml.security.utils.resolver.ResourceResolverSpi;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
/**
* This resolver is used for resolving same-document URIs like URI="" of URI="#id".
*
* @author $Author: coheigea $
* @see <A HREF="http://www.w3.org/TR/xmldsig-core/#sec-ReferenceProcessingModel">The Reference processing model in the XML Signature spec</A>
* @see <A HREF="http://www.w3.org/TR/xmldsig-core/#sec-Same-Document">Same-Document URI-References in the XML Signature spec</A>
* @see <A HREF="http://www.ietf.org/rfc/rfc2396.txt">Section 4.2 of RFC 2396</A>
*/
public class ResolverFragment extends ResourceResolverSpi {
/** {@link de.kp.logging} logging facility */
private static de.kp.logging.Log log =
de.kp.logging.LogFactory.getLog(ResolverFragment.class);
@Override
public boolean engineIsThreadSafe() {
return true;
}
/**
* Method engineResolve
*
* @inheritDoc
* @param uri
* @param baseURI
*/
public XMLSignatureInput engineResolve(Attr uri, String baseURI)
throws ResourceResolverException {
String uriNodeValue = uri.getNodeValue();
Document doc = uri.getOwnerElement().getOwnerDocument();
Node selectedElem = null;
if (uriNodeValue.equals("")) {
/*
* Identifies the node-set (minus any comment nodes) of the XML
* resource containing the signature
*/
if (log.isDebugEnabled()) {
log.debug("ResolverFragment with empty URI (means complete document)");
}
selectedElem = doc;
} else {
/*
* URI="#chapter1"
* Identifies a node-set containing the element with ID attribute
* value 'chapter1' of the XML resource containing the signature.
* XML Signature (and its applications) modify this node-set to
* include the element plus all descendants including namespaces and
* attributes -- but not comments.
*/
String id = uriNodeValue.substring(1);
selectedElem = doc.getElementById(id);
if (selectedElem == null) {
Object exArgs[] = { id };
throw new ResourceResolverException(
"signature.Verification.MissingID", exArgs, uri, baseURI
);
}
if (secureValidation) {
Element start = uri.getOwnerDocument().getDocumentElement();
if (!XMLUtils.protectAgainstWrappingAttack(start, id)) {
Object exArgs[] = { id };
throw new ResourceResolverException(
"signature.Verification.MultipleIDs", exArgs, uri, baseURI
);
}
}
if (log.isDebugEnabled()) {
log.debug(
"Try to catch an Element with ID " + id + " and Element was " + selectedElem
);
}
}
XMLSignatureInput result = new XMLSignatureInput(selectedElem);
result.setExcludeComments(true);
result.setMIMEType("text/xml");
if (baseURI != null && baseURI.length() > 0) {
result.setSourceURI(baseURI.concat(uri.getNodeValue()));
} else {
result.setSourceURI(uri.getNodeValue());
}
return result;
}
/**
* Method engineCanResolve
* @inheritDoc
* @param uri
* @param baseURI
*/
public boolean engineCanResolve(Attr uri, String baseURI) {
if (uri == null) {
if (log.isDebugEnabled()) {
log.debug("Quick fail for null uri");
}
return false;
}
String uriNodeValue = uri.getNodeValue();
if (uriNodeValue.equals("") ||
((uriNodeValue.charAt(0) == '#') && !uriNodeValue.startsWith("#xpointer("))
) {
if (log.isDebugEnabled()) {
log.debug("State I can resolve reference: \"" + uriNodeValue + "\"");
}
return true;
}
if (log.isDebugEnabled()) {
log.debug("Do not seem to be able to resolve reference: \"" + uriNodeValue + "\"");
}
return false;
}
}