/**
* 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;
/**
* Handles barename XPointer Reference URIs.
* <BR />
* To retain comments while selecting an element by an identifier ID,
* use the following full XPointer: URI='#xpointer(id('ID'))'.
* <BR />
* To retain comments while selecting the entire document,
* use the following full XPointer: URI='#xpointer(/)'.
* This XPointer contains a simple XPath expression that includes
* the root node, which the second to last step above replaces with all
* nodes of the parse tree (all descendants, plus all attributes,
* plus all namespaces nodes).
*
* @author $Author: coheigea $
*/
public class ResolverXPointer extends ResourceResolverSpi {
/** {@link de.kp.logging} logging facility */
private static de.kp.logging.Log log =
de.kp.logging.LogFactory.getLog(ResolverXPointer.class);
private static final String XP = "#xpointer(id(";
private static final int XP_LENGTH = XP.length();
@Override
public boolean engineIsThreadSafe() {
return true;
}
/**
* @inheritDoc
*/
public XMLSignatureInput engineResolve(Attr uri, String baseURI)
throws ResourceResolverException {
Node resultNode = null;
Document doc = uri.getOwnerElement().getOwnerDocument();
String uriStr = uri.getNodeValue();
if (isXPointerSlash(uriStr)) {
resultNode = doc;
} else if (isXPointerId(uriStr)) {
String id = getXPointerId(uriStr);
resultNode = doc.getElementById(id);
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 (resultNode == null) {
Object exArgs[] = { id };
throw new ResourceResolverException(
"signature.Verification.MissingID", exArgs, uri, baseURI
);
}
}
XMLSignatureInput result = new XMLSignatureInput(resultNode);
result.setMIMEType("text/xml");
if (baseURI != null && baseURI.length() > 0) {
result.setSourceURI(baseURI.concat(uri.getNodeValue()));
} else {
result.setSourceURI(uri.getNodeValue());
}
return result;
}
/**
* @inheritDoc
*/
public boolean engineCanResolve(Attr uri, String baseURI) {
if (uri == null) {
return false;
}
String uriStr = uri.getNodeValue();
if (isXPointerSlash(uriStr) || isXPointerId(uriStr)) {
return true;
}
return false;
}
/**
* Method isXPointerSlash
*
* @param uri
* @return true if begins with xpointer
*/
private static boolean isXPointerSlash(String uri) {
if (uri.equals("#xpointer(/)")) {
return true;
}
return false;
}
/**
* Method isXPointerId
*
* @param uri
* @return whether it has an xpointer id
*/
private static boolean isXPointerId(String uri) {
if (uri.startsWith(XP) && uri.endsWith("))")) {
String idPlusDelim = uri.substring(XP_LENGTH, uri.length() - 2);
int idLen = idPlusDelim.length() -1;
if (((idPlusDelim.charAt(0) == '"') && (idPlusDelim.charAt(idLen) == '"'))
|| ((idPlusDelim.charAt(0) == '\'') && (idPlusDelim.charAt(idLen) == '\''))) {
if (log.isDebugEnabled()) {
log.debug("Id = " + idPlusDelim.substring(1, idLen));
}
return true;
}
}
return false;
}
/**
* Method getXPointerId
*
* @param uri
* @return xpointerId to search.
*/
private static String getXPointerId(String uri) {
if (uri.startsWith(XP) && uri.endsWith("))")) {
String idPlusDelim = uri.substring(XP_LENGTH,uri.length() - 2);
int idLen = idPlusDelim.length() -1;
if (((idPlusDelim.charAt(0) == '"') && (idPlusDelim.charAt(idLen) == '"'))
|| ((idPlusDelim.charAt(0) == '\'') && (idPlusDelim.charAt(idLen) == '\''))) {
return idPlusDelim.substring(1, idLen);
}
}
return null;
}
}