| /** |
| * 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.staxutils; |
| |
| import java.util.Stack; |
| |
| import javax.xml.stream.XMLStreamException; |
| import javax.xml.stream.XMLStreamReader; |
| |
| /** |
| * XMLStreamReader implementation which can be used to enforce a number of |
| * depth-restricting policies. The following properties are currently supported: |
| * - total number of elements in the document |
| * - the maximum depth of the given element; the root element will be checked by default |
| * - the maximum number of immediate child nodes for individual elements |
| * |
| * More sophisticated policies can be supported in the future. |
| */ |
| public class DepthRestrictingStreamReader extends DepthXMLStreamReader { |
| |
| private DocumentDepthProperties props; |
| private int totalElementCount; |
| private Stack<Integer> stack = new Stack<>(); |
| |
| public DepthRestrictingStreamReader(XMLStreamReader reader, |
| int elementCountThreshold, |
| int innerElementLevelThreshold, |
| int innerElementCountThreshold) { |
| this(reader, new DocumentDepthProperties(elementCountThreshold, |
| innerElementLevelThreshold, |
| innerElementCountThreshold)); |
| } |
| |
| public DepthRestrictingStreamReader(XMLStreamReader reader, |
| DocumentDepthProperties props) { |
| super(reader); |
| this.props = props; |
| } |
| |
| @Override |
| public int next() throws XMLStreamException { |
| int next = super.next(); |
| if (next == START_ELEMENT) { |
| if (props.getInnerElementLevelThreshold() != -1 |
| && getDepth() >= props.getInnerElementLevelThreshold()) { |
| throw new DepthExceededStaxException(); |
| } |
| if (props.getElementCountThreshold() != -1 |
| && ++totalElementCount >= props.getElementCountThreshold()) { |
| throw new DepthExceededStaxException(); |
| } |
| if (props.getInnerElementCountThreshold() != -1) { |
| if (!stack.empty()) { |
| int currentCount = stack.pop(); |
| if (++currentCount >= props.getInnerElementCountThreshold()) { |
| throw new DepthExceededStaxException(); |
| } |
| stack.push(currentCount); |
| } |
| stack.push(0); |
| } |
| |
| } else if (next == END_ELEMENT && props.getInnerElementCountThreshold() != -1) { |
| stack.pop(); |
| } |
| return next; |
| } |
| } |