/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* 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 com.sun.org.apache.xml.internal.security.utils;
import java.io.IOException;
import java.io.OutputStream;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.sun.org.apache.xml.internal.security.c14n.CanonicalizationException;
import com.sun.org.apache.xml.internal.security.c14n.Canonicalizer;
import com.sun.org.apache.xml.internal.security.c14n.InvalidCanonicalizerException;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
DOM and XML accessibility and comfort functions.
Author: Christian Geuer-Pollmann
/**
* DOM and XML accessibility and comfort functions.
*
* @author Christian Geuer-Pollmann
*/
public class XMLUtils {
private static boolean ignoreLineBreaks =
AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
public Boolean run() {
return Boolean.getBoolean
("com.sun.org.apache.xml.internal.security.ignoreLineBreaks");
}
});
private static volatile String dsPrefix = "ds";
private static volatile String xencPrefix = "xenc";
private static final java.util.logging.Logger log =
java.util.logging.Logger.getLogger(XMLUtils.class.getName());
Constructor XMLUtils
/**
* Constructor XMLUtils
*
*/
private XMLUtils() {
// we don't allow instantiation
}
Set the prefix for the digital signature namespace
Params: - prefix – the new prefix for the digital signature namespace
Throws: - SecurityException – if a security manager is installed and the
caller does not have permission to set the prefix
/**
* Set the prefix for the digital signature namespace
* @param prefix the new prefix for the digital signature namespace
* @throws SecurityException if a security manager is installed and the
* caller does not have permission to set the prefix
*/
public static void setDsPrefix(String prefix) {
JavaUtils.checkRegisterPermission();
dsPrefix = prefix;
}
Set the prefix for the encryption namespace
Params: - prefix – the new prefix for the encryption namespace
Throws: - SecurityException – if a security manager is installed and the
caller does not have permission to set the prefix
/**
* Set the prefix for the encryption namespace
* @param prefix the new prefix for the encryption namespace
* @throws SecurityException if a security manager is installed and the
* caller does not have permission to set the prefix
*/
public static void setXencPrefix(String prefix) {
JavaUtils.checkRegisterPermission();
xencPrefix = prefix;
}
public static Element getNextElement(Node el) {
while ((el!=null) && (el.getNodeType()!=Node.ELEMENT_NODE)) {
el=el.getNextSibling();
}
return (Element)el;
}
Params: - rootNode –
- result –
- exclude –
- com – wheather comments or not
/**
* @param rootNode
* @param result
* @param exclude
* @param com wheather comments or not
*/
public static void getSet(Node rootNode,Set<Node> result,Node exclude ,boolean com) {
if ((exclude!=null) && isDescendantOrSelf(exclude,rootNode)){
return;
}
getSetRec(rootNode,result,exclude,com);
}
@SuppressWarnings("fallthrough")
static final void getSetRec(final Node rootNode,final Set<Node> result,
final Node exclude ,final boolean com) {
//Set result = new HashSet();
if (rootNode==exclude) {
return;
}
switch (rootNode.getNodeType()) {
case Node.ELEMENT_NODE:
result.add(rootNode);
Element el=(Element)rootNode;
if (el.hasAttributes()) {
NamedNodeMap nl = ((Element)rootNode).getAttributes();
for (int i=0;i<nl.getLength();i++) {
result.add(nl.item(i));
}
}
//no return keep working - ignore fallthrough warning
case Node.DOCUMENT_NODE:
for (Node r=rootNode.getFirstChild();r!=null;r=r.getNextSibling()){
if (r.getNodeType()==Node.TEXT_NODE) {
result.add(r);
while ((r!=null) && (r.getNodeType()==Node.TEXT_NODE)) {
r=r.getNextSibling();
}
if (r==null)
return;
}
getSetRec(r,result,exclude,com);
}
return;
case Node.COMMENT_NODE:
if (com) {
result.add(rootNode);
}
return;
case Node.DOCUMENT_TYPE_NODE:
return;
default:
result.add(rootNode);
}
return;
}
Outputs a DOM tree to an OutputStream. Params: - contextNode – root node of the DOM tree
- os – the
OutputStream
/**
* Outputs a DOM tree to an {@link OutputStream}.
*
* @param contextNode root node of the DOM tree
* @param os the {@link OutputStream}
*/
public static void outputDOM(Node contextNode, OutputStream os) {
XMLUtils.outputDOM(contextNode, os, false);
}
Outputs a DOM tree to an OutputStream. If an Exception is
thrown during execution, it's StackTrace is output to System.out, but the
Exception is not re-thrown.
Params: - contextNode – root node of the DOM tree
- os – the
OutputStream - addPreamble –
/**
* Outputs a DOM tree to an {@link OutputStream}. <I>If an Exception is
* thrown during execution, it's StackTrace is output to System.out, but the
* Exception is not re-thrown.</I>
*
* @param contextNode root node of the DOM tree
* @param os the {@link OutputStream}
* @param addPreamble
*/
public static void outputDOM(Node contextNode, OutputStream os,
boolean addPreamble) {
try {
if (addPreamble) {
os.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n".getBytes());
}
os.write(
Canonicalizer.getInstance(
Canonicalizer.ALGO_ID_C14N_WITH_COMMENTS).canonicalizeSubtree(
contextNode));
} catch (IOException ex) {}
catch (InvalidCanonicalizerException ex) {
ex.printStackTrace();
} catch (CanonicalizationException ex) {
ex.printStackTrace();
}
}
Serializes the contextNode into the OutputStream, but
supresses all Exceptions.
NOTE: This should only be used for debugging purposes,
NOT in a production environment; this method ignores all exceptions,
so you won't notice if something goes wrong. If you're asking what is to
be used in a production environment, simply use the code inside the
try{} statement, but handle the Exceptions appropriately.
Params: - contextNode –
- os –
/**
* Serializes the <CODE>contextNode</CODE> into the OutputStream, <I>but
* supresses all Exceptions</I>.
* <BR />
* NOTE: <I>This should only be used for debugging purposes,
* NOT in a production environment; this method ignores all exceptions,
* so you won't notice if something goes wrong. If you're asking what is to
* be used in a production environment, simply use the code inside the
* <code>try{}</code> statement, but handle the Exceptions appropriately.</I>
*
* @param contextNode
* @param os
*/
public static void outputDOMc14nWithComments(Node contextNode,
OutputStream os) {
try {
os.write(
Canonicalizer.getInstance(
Canonicalizer.ALGO_ID_C14N_WITH_COMMENTS).canonicalizeSubtree(
contextNode));
} catch (IOException ex) {
// throw new RuntimeException(ex.getMessage());
} catch (InvalidCanonicalizerException ex) {
// throw new RuntimeException(ex.getMessage());
} catch (CanonicalizationException ex) {
// throw new RuntimeException(ex.getMessage());
}
}
Method getFullTextChildrenFromElement
Params: - element –
Returns: the string of chi;ds
/**
* Method getFullTextChildrenFromElement
*
* @param element
* @return the string of chi;ds
*/
public static String getFullTextChildrenFromElement(Element element) {
StringBuffer sb = new StringBuffer();
NodeList children = element.getChildNodes();
int iMax = children.getLength();
for (int i = 0; i < iMax; i++) {
Node curr = children.item(i);
if (curr.getNodeType() == Node.TEXT_NODE) {
sb.append(((Text) curr).getData());
}
}
return sb.toString();
}
static Map<String, String> namePrefixes=new HashMap<String, String>();
Creates an Element in the XML Signature specification namespace.
Params: - doc – the factory Document
- elementName – the local name of the Element
Returns: the Element
/**
* Creates an Element in the XML Signature specification namespace.
*
* @param doc the factory Document
* @param elementName the local name of the Element
* @return the Element
*/
public static Element createElementInSignatureSpace(Document doc,
String elementName) {
if (doc == null) {
throw new RuntimeException("Document is null");
}
if ((dsPrefix == null) || (dsPrefix.length() == 0)) {
return doc.createElementNS(Constants.SignatureSpecNS, elementName);
}
String namePrefix= namePrefixes.get(elementName);
if (namePrefix==null) {
StringBuffer tag=new StringBuffer(dsPrefix);
tag.append(':');
tag.append(elementName);
namePrefix=tag.toString();
namePrefixes.put(elementName,namePrefix);
}
return doc.createElementNS(Constants.SignatureSpecNS, namePrefix);
}
Returns true if the element is in XML Signature namespace and the local
name equals the supplied one.
Params: - element –
- localName –
Returns: true if the element is in XML Signature namespace and the local name equals the supplied one
/**
* Returns true if the element is in XML Signature namespace and the local
* name equals the supplied one.
*
* @param element
* @param localName
* @return true if the element is in XML Signature namespace and the local name equals the supplied one
*/
public static boolean elementIsInSignatureSpace(Element element, String localName) {
if (element == null) {
return false;
}
return Constants.SignatureSpecNS.equals(element.getNamespaceURI())
&& element.getLocalName().equals(localName);
}
Returns true if the element is in XML Encryption namespace and the local
name equals the supplied one.
Params: - element –
- localName –
Returns: true if the element is in XML Encryption namespace and the local name equals the supplied one
/**
* Returns true if the element is in XML Encryption namespace and the local
* name equals the supplied one.
*
* @param element
* @param localName
* @return true if the element is in XML Encryption namespace and the local name equals the supplied one
*/
public static boolean elementIsInEncryptionSpace(Element element, String localName) {
if (element == null) {
return false;
}
return EncryptionConstants.EncryptionSpecNS.equals(element.getNamespaceURI())
&& element.getLocalName().equals(localName);
}
This method returns the owner document of a particular node.
This method is necessary because it always returns a Document. getOwnerDocument.getOwnerDocument returns null if the Node is a Document. Params: - node –
Returns: the owner document of the node
/**
* This method returns the owner document of a particular node.
* This method is necessary because it <I>always</I> returns a
* {@link Document}. {@link Node#getOwnerDocument} returns <CODE>null</CODE>
* if the {@link Node} is a {@link Document}.
*
* @param node
* @return the owner document of the node
*/
public static Document getOwnerDocument(Node node) {
if (node.getNodeType() == Node.DOCUMENT_NODE) {
return (Document) node;
}
try {
return node.getOwnerDocument();
} catch (NullPointerException npe) {
throw new NullPointerException(I18n.translate("endorsed.jdk1.4.0")
+ " Original message was \""
+ npe.getMessage() + "\"");
}
}
This method returns the first non-null owner document of the Node's in this Set.
This method is necessary because it always returns a Document. getOwnerDocument.getOwnerDocument returns null if the Node is a Document. Params: - xpathNodeSet –
Returns: the owner document
/**
* This method returns the first non-null owner document of the Node's in this Set.
* This method is necessary because it <I>always</I> returns a
* {@link Document}. {@link Node#getOwnerDocument} returns <CODE>null</CODE>
* if the {@link Node} is a {@link Document}.
*
* @param xpathNodeSet
* @return the owner document
*/
public static Document getOwnerDocument(Set<Node> xpathNodeSet) {
NullPointerException npe = null;
for (Node node : xpathNodeSet) {
int nodeType =node.getNodeType();
if (nodeType == Node.DOCUMENT_NODE) {
return (Document) node;
}
try {
if (nodeType==Node.ATTRIBUTE_NODE) {
return ((Attr)node).getOwnerElement().getOwnerDocument();
}
return node.getOwnerDocument();
} catch (NullPointerException e) {
npe = e;
}
}
throw new NullPointerException(I18n.translate("endorsed.jdk1.4.0")
+ " Original message was \""
+ (npe == null ? "" : npe.getMessage()) + "\"");
}
Method createDSctx
Params: - doc –
- prefix –
- namespace –
Returns: the element.
/**
* Method createDSctx
*
* @param doc
* @param prefix
* @param namespace
* @return the element.
*/
public static Element createDSctx(Document doc, String prefix,
String namespace) {
if ((prefix == null) || (prefix.trim().length() == 0)) {
throw new IllegalArgumentException("You must supply a prefix");
}
Element ctx = doc.createElementNS(null, "namespaceContext");
ctx.setAttributeNS(Constants.NamespaceSpecNS, "xmlns:" + prefix.trim(),
namespace);
return ctx;
}
Method addReturnToElement
Params: - e –
/**
* Method addReturnToElement
*
* @param e
*/
public static void addReturnToElement(Element e) {
if (!ignoreLineBreaks) {
Document doc = e.getOwnerDocument();
e.appendChild(doc.createTextNode("\n"));
}
}
public static void addReturnToElement(Document doc, HelperNodeList nl) {
if (!ignoreLineBreaks) {
nl.appendChild(doc.createTextNode("\n"));
}
}
public static void addReturnBeforeChild(Element e, Node child) {
if (!ignoreLineBreaks) {
Document doc = e.getOwnerDocument();
e.insertBefore(doc.createTextNode("\n"), child);
}
}
Method convertNodelistToSet
Params: - xpathNodeSet –
Returns: the set with the nodelist
/**
* Method convertNodelistToSet
*
* @param xpathNodeSet
* @return the set with the nodelist
*/
public static Set<Node> convertNodelistToSet(NodeList xpathNodeSet) {
if (xpathNodeSet == null) {
return new HashSet<Node>();
}
int length = xpathNodeSet.getLength();
Set<Node> set = new HashSet<Node>(length);
for (int i = 0; i < length; i++) {
set.add(xpathNodeSet.item(i));
}
return set;
}
This method spreads all namespace attributes in a DOM document to their
children. This is needed because the XML Signature XPath transform
must evaluate the XPath against all nodes in the input, even against
XPath namespace nodes. Through a bug in XalanJ2, the namespace nodes are
not fully visible in the Xalan XPath model, so we have to do this by
hand in DOM spaces so that the nodes become visible in XPath space.
Params: - doc –
See Also:
/**
* This method spreads all namespace attributes in a DOM document to their
* children. This is needed because the XML Signature XPath transform
* must evaluate the XPath against all nodes in the input, even against
* XPath namespace nodes. Through a bug in XalanJ2, the namespace nodes are
* not fully visible in the Xalan XPath model, so we have to do this by
* hand in DOM spaces so that the nodes become visible in XPath space.
*
* @param doc
* @see <A HREF="http://nagoya.apache.org/bugzilla/show_bug.cgi?id=2650">Namespace axis resolution is not XPath compliant </A>
*/
public static void circumventBug2650(Document doc) {
Element documentElement = doc.getDocumentElement();
// if the document element has no xmlns definition, we add xmlns=""
Attr xmlnsAttr =
documentElement.getAttributeNodeNS(Constants.NamespaceSpecNS, "xmlns");
if (xmlnsAttr == null) {
documentElement.setAttributeNS(Constants.NamespaceSpecNS, "xmlns", "");
}
XMLUtils.circumventBug2650internal(doc);
}
This is the work horse for circumventBug2650. Params: - node –
See Also:
/**
* This is the work horse for {@link #circumventBug2650}.
*
* @param node
* @see <A HREF="http://nagoya.apache.org/bugzilla/show_bug.cgi?id=2650">Namespace axis resolution is not XPath compliant </A>
*/
@SuppressWarnings("fallthrough")
private static void circumventBug2650internal(Node node) {
Node parent=null;
Node sibling=null;
final String namespaceNs=Constants.NamespaceSpecNS;
do {
switch (node.getNodeType()) {
case Node.ELEMENT_NODE :
Element element = (Element) node;
if (!element.hasChildNodes())
break;
if (element.hasAttributes()) {
NamedNodeMap attributes = element.getAttributes();
int attributesLength = attributes.getLength();
for (Node child = element.getFirstChild(); child!=null;
child=child.getNextSibling()) {
if (child.getNodeType() != Node.ELEMENT_NODE) {
continue;
}
Element childElement = (Element) child;
for (int i = 0; i < attributesLength; i++) {
Attr currentAttr = (Attr) attributes.item(i);
if (namespaceNs!=currentAttr.getNamespaceURI())
continue;
if (childElement.hasAttributeNS(namespaceNs,
currentAttr.getLocalName())) {
continue;
}
childElement.setAttributeNS(namespaceNs,
currentAttr.getName(),
currentAttr.getNodeValue());
}
}
}
case Node.ENTITY_REFERENCE_NODE :
case Node.DOCUMENT_NODE :
parent=node;
sibling=node.getFirstChild();
break;
}
while ((sibling==null) && (parent!=null)) {
sibling=parent.getNextSibling();
parent=parent.getParentNode();
};
if (sibling==null) {
return;
}
node=sibling;
sibling=node.getNextSibling();
} while (true);
}
Params: - sibling –
- nodeName –
- number –
Returns: nodes with the constrain
/**
* @param sibling
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Element selectDsNode(Node sibling, String nodeName, int number) {
while (sibling != null) {
if (Constants.SignatureSpecNS.equals(sibling.getNamespaceURI())
&& sibling.getLocalName().equals(nodeName)) {
if (number == 0){
return (Element)sibling;
}
number--;
}
sibling = sibling.getNextSibling();
}
return null;
}
Params: - sibling –
- nodeName –
- number –
Returns: nodes with the constrain
/**
* @param sibling
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Element selectXencNode(Node sibling, String nodeName, int number) {
while (sibling != null) {
if (EncryptionConstants.EncryptionSpecNS.equals(sibling.getNamespaceURI())
&& sibling.getLocalName().equals(nodeName)) {
if (number == 0){
return (Element)sibling;
}
number--;
}
sibling = sibling.getNextSibling();
}
return null;
}
Params: - sibling –
- nodeName –
- number –
Returns: nodes with the constrain
/**
* @param sibling
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Text selectDsNodeText(Node sibling, String nodeName, int number) {
Node n=selectDsNode(sibling,nodeName,number);
if (n==null) {
return null;
}
n=n.getFirstChild();
while (n!=null && n.getNodeType()!=Node.TEXT_NODE) {
n=n.getNextSibling();
}
return (Text)n;
}
Params: - sibling –
- uri –
- nodeName –
- number –
Returns: nodes with the constrain
/**
* @param sibling
* @param uri
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Text selectNodeText(Node sibling, String uri, String nodeName, int number) {
Node n=selectNode(sibling,uri,nodeName,number);
if (n==null) {
return null;
}
n=n.getFirstChild();
while (n!=null && n.getNodeType()!=Node.TEXT_NODE) {
n=n.getNextSibling();
}
return (Text)n;
}
Params: - sibling –
- uri –
- nodeName –
- number –
Returns: nodes with the constrain
/**
* @param sibling
* @param uri
* @param nodeName
* @param number
* @return nodes with the constrain
*/
public static Element selectNode(Node sibling, String uri, String nodeName, int number) {
while (sibling != null) {
if (sibling.getNamespaceURI() != null && sibling.getNamespaceURI().equals(uri)
&& sibling.getLocalName().equals(nodeName)) {
if (number == 0){
return (Element)sibling;
}
number--;
}
sibling = sibling.getNextSibling();
}
return null;
}
Params: - sibling –
- nodeName –
Returns: nodes with the constrain
/**
* @param sibling
* @param nodeName
* @return nodes with the constrain
*/
public static Element[] selectDsNodes(Node sibling, String nodeName) {
return selectNodes(sibling,Constants.SignatureSpecNS, nodeName);
}
Params: - sibling –
- uri –
- nodeName –
Returns: nodes with the constrain
/**
* @param sibling
* @param uri
* @param nodeName
* @return nodes with the constrain
*/
public static Element[] selectNodes(Node sibling, String uri, String nodeName) {
List<Element> list = new ArrayList<Element>();
while (sibling != null) {
if (sibling.getNamespaceURI() != null && sibling.getNamespaceURI().equals(uri)
&& sibling.getLocalName().equals(nodeName)) {
list.add((Element)sibling);
}
sibling = sibling.getNextSibling();
}
return list.toArray(new Element[list.size()]);
}
Params: - signatureElement –
- inputSet –
Returns: nodes with the constrain
/**
* @param signatureElement
* @param inputSet
* @return nodes with the constrain
*/
public static Set<Node> excludeNodeFromSet(Node signatureElement, Set<Node> inputSet) {
Set<Node> resultSet = new HashSet<Node>();
Iterator<Node> iterator = inputSet.iterator();
while (iterator.hasNext()) {
Node inputNode = iterator.next();
if (!XMLUtils
.isDescendantOrSelf(signatureElement, inputNode)) {
resultSet.add(inputNode);
}
}
return resultSet;
}
Returns true if the descendantOrSelf is on the descendant-or-self axis
of the context node.
Params: - ctx –
- descendantOrSelf –
Returns: true if the node is descendant
/**
* Returns true if the descendantOrSelf is on the descendant-or-self axis
* of the context node.
*
* @param ctx
* @param descendantOrSelf
* @return true if the node is descendant
*/
static public boolean isDescendantOrSelf(Node ctx, Node descendantOrSelf) {
if (ctx == descendantOrSelf) {
return true;
}
Node parent = descendantOrSelf;
while (true) {
if (parent == null) {
return false;
}
if (parent == ctx) {
return true;
}
if (parent.getNodeType() == Node.ATTRIBUTE_NODE) {
parent = ((Attr) parent).getOwnerElement();
} else {
parent = parent.getParentNode();
}
}
}
public static boolean ignoreLineBreaks() {
return ignoreLineBreaks;
}
This method is a tree-search to help prevent against wrapping attacks.
It checks that no two Elements have ID Attributes that match the "value"
argument, if this is the case then "false" is returned. Note that a
return value of "true" does not necessarily mean that a matching Element
has been found, just that no wrapping attack has been detected.
/**
* This method is a tree-search to help prevent against wrapping attacks.
* It checks that no two Elements have ID Attributes that match the "value"
* argument, if this is the case then "false" is returned. Note that a
* return value of "true" does not necessarily mean that a matching Element
* has been found, just that no wrapping attack has been detected.
*/
public static boolean protectAgainstWrappingAttack(Node startNode,
String value)
{
Node startParent = startNode.getParentNode();
Node processedNode = null;
Element foundElement = null;
String id = value.trim();
if (id.charAt(0) == '#') {
id = id.substring(1);
}
while (startNode != null) {
if (startNode.getNodeType() == Node.ELEMENT_NODE) {
Element se = (Element) startNode;
NamedNodeMap attributes = se.getAttributes();
if (attributes != null) {
for (int i = 0; i < attributes.getLength(); i++) {
Attr attr = (Attr)attributes.item(i);
if (attr.isId() && id.equals(attr.getValue())) {
if (foundElement == null) {
// Continue searching to find duplicates
foundElement = attr.getOwnerElement();
} else {
log.log(java.util.logging.Level.FINE, "Multiple elements with the same 'Id' attribute value!");
return false;
}
}
}
}
}
processedNode = startNode;
startNode = startNode.getFirstChild();
// no child, this node is done.
if (startNode == null) {
// close node processing, get sibling
startNode = processedNode.getNextSibling();
}
// no more siblings, get parent, all children
// of parent are processed.
while (startNode == null) {
processedNode = processedNode.getParentNode();
if (processedNode == startParent) {
return true;
}
// close parent node processing (processed node now)
startNode = processedNode.getNextSibling();
}
}
return true;
}
This method is a tree-search to help prevent against wrapping attacks.
It checks that no other Element than the given "knownElement" argument
has an ID attribute that matches the "value" argument, which is the ID
value of "knownElement". If this is the case then "false" is returned.
/**
* This method is a tree-search to help prevent against wrapping attacks.
* It checks that no other Element than the given "knownElement" argument
* has an ID attribute that matches the "value" argument, which is the ID
* value of "knownElement". If this is the case then "false" is returned.
*/
public static boolean protectAgainstWrappingAttack(Node startNode,
Element knownElement,
String value)
{
Node startParent = startNode.getParentNode();
Node processedNode = null;
String id = value.trim();
if (id.charAt(0) == '#') {
id = id.substring(1);
}
while (startNode != null) {
if (startNode.getNodeType() == Node.ELEMENT_NODE) {
Element se = (Element) startNode;
NamedNodeMap attributes = se.getAttributes();
if (attributes != null) {
for (int i = 0; i < attributes.getLength(); i++) {
Attr attr = (Attr)attributes.item(i);
if (attr.isId() && id.equals(attr.getValue())
&& se != knownElement)
{
log.log(java.util.logging.Level.FINE, "Multiple elements with the same 'Id' attribute value!");
return false;
}
}
}
}
processedNode = startNode;
startNode = startNode.getFirstChild();
// no child, this node is done.
if (startNode == null) {
// close node processing, get sibling
startNode = processedNode.getNextSibling();
}
// no more siblings, get parent, all children
// of parent are processed.
while (startNode == null) {
processedNode = processedNode.getParentNode();
if (processedNode == startParent) {
return true;
}
// close parent node processing (processed node now)
startNode = processedNode.getNextSibling();
}
}
return true;
}
}