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atorralbaatorralba
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WIP: XPath Injection promotion
1 parent 8b2009c commit ed56194

8 files changed

Lines changed: 202 additions & 24 deletions

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‎java/ql/src/experimental/Security/CWE/CWE-643/XPathInjection.ql‎

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*/
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import java
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import semmle.code.java.dataflow.FlowSources
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import semmle.code.java.dataflow.TaintTracking
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import semmle.code.java.security.XmlParsers
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import DataFlow::PathGraph
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class XPathInjectionConfiguration extends TaintTracking::Configuration {
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XPathInjectionConfiguration() { this = "XPathInjection" }
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override predicate isSource(DataFlow::Node source) { source instanceof RemoteFlowSource }
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override predicate isSink(DataFlow::Node sink) { sink instanceof XPathInjectionSink }
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}
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class XPathInjectionSink extends DataFlow::ExprNode {
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XPathInjectionSink() {
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exists(Method m, MethodAccess ma | ma.getMethod() = m |
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m.getDeclaringType().hasQualifiedName("javax.xml.xpath", "XPath") and
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(m.hasName("evaluate") or m.hasName("compile")) and
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ma.getArgument(0) = this.getExpr()
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or
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m.getDeclaringType().hasQualifiedName("org.dom4j", "Node") and
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(m.hasName("selectNodes") or m.hasName("selectSingleNode")) and
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ma.getArgument(0) = this.getExpr()
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)
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}
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}
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import semmle.code.java.security.XPath
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from DataFlow::PathNode source, DataFlow::PathNode sink, XPathInjectionConfiguration c
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where c.hasFlowPath(source, sink)

‎java/ql/src/semmle/code/java/security/XPath.qll‎

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import semmle.code.java.dataflow.FlowSources
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import semmle.code.java.dataflow.TaintTracking
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import semmle.code.java.security.XmlParsers
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/**
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* An abstract type representing a call to interpret XPath expressions.
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*/
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class XPathSink extends MethodAccess {
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abstract Expr getSink();
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}
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/** The class `javax.xml.xpath.XPath` */
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class XPath extends RefType {
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XPath() { this.hasQualifiedName("javax.xml.xpath", "XPath") }
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}
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/** A call to `XPath.Evaluate` or `XPath.compile` */
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class XPathEvaluateOrCompile extends XPathSink {
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XPathEvaluateOrCompile() {
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exists(Method m | this.getMethod() = m and m.getDeclaringType() instanceof XPath |
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m.hasName("evaluate")
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or
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m.hasName("compile")
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)
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}
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override Expr getSink() { result = this.getArgument(0) }
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}
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/** The class `org.dom4j.Node` */
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class Dom4JNode extends RefType {
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Dom4JNode() { this.hasQualifiedName("org.dom4j", "Node") }
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}
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/** A call to `Node.selectNodes` or `Node.selectSingleNode` */
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class NodeSelectNodes extends XPathSink {
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NodeSelectNodes() {
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exists(Method m | this.getMethod() = m and m.getDeclaringType() instanceof Dom4JNode |
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m.hasName("selectNodes") or m.hasName("selectSingleNode")
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)
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}
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override Expr getSink() { result = this.getArgument(0) }
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}
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class XPathInjectionSink extends DataFlow::ExprNode {
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XPathInjectionSink() { exists(XPathSink sink | this.getExpr() = sink.getSink()) }
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}
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class XPathInjectionConfiguration extends TaintTracking::Configuration {
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XPathInjectionConfiguration() { this = "XPathInjection" }
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override predicate isSource(DataFlow::Node source) { source instanceof RemoteFlowSource }
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override predicate isSink(DataFlow::Node sink) { sink instanceof XPathInjectionSink }
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}

‎java/ql/test/experimental/query-tests/security/CWE-643/A.java‎

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import javax.xml.*;
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import org.w3c.dom.Document;
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import org.xml.sax.InputSource;
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import org.xml.sax.SAXException;
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import javax.xml.parsers.DocumentBuilder;
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import javax.xml.parsers.DocumentBuilderFactory;
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import javax.xml.parsers.ParserConfigurationException;
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import javax.xml.xpath.XPath;
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import javax.xml.xpath.XPathConstants;
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import javax.xml.xpath.XPathExpression;
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import javax.xml.xpath.XPathExpressionException;
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import javax.xml.xpath.XPathFactory;
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import java.io.BufferedInputStream;
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import java.io.ByteArrayInputStream;
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import java.io.InputStream;
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import java.io.StringReader;
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import javax.servlet.http.HttpServletRequest;
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public class A {
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public void handle(HttpServletRequest request) throws Exception {
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final String xmlStr = "<users>" + " <user name=\"aaa\" pass=\"pass1\"></user>"
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+ " <user name=\"bbb\" pass=\"pass2\"></user>" + "</users>";
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DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
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domFactory.setNamespaceAware(true);
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DocumentBuilder builder = domFactory.newDocumentBuilder();
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Document doc = builder.parse(new InputSource(new StringReader(xmlStr)));
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XPathFactory factory = XPathFactory.newInstance();
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XPath xpath = factory.newXPath();
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// Injectable data
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String user = request.getParameter("user");
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String pass = request.getParameter("pass");
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if (user != null && pass != null) {
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boolean isExist = false;
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// Bad expression
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String expression1 = "/users/user[@name='" + user + "' and @pass='" + pass + "']";
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isExist = (boolean) xpath.evaluate(expression1, doc, XPathConstants.BOOLEAN); // $hasXPathInjection
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System.out.println(isExist);
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// Bad expression
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XPathExpression expression2 = xpath.compile("/users/user[@name='" + user + "' and @pass='" + pass + "']"); // $hasXPathInjection
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isExist = (boolean) expression2.evaluate(doc, XPathConstants.BOOLEAN);
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System.out.println(isExist);
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// Bad expression
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StringBuffer sb = new StringBuffer("/users/user[@name=");
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sb.append(user);
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sb.append("' and @pass='");
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sb.append(pass);
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sb.append("']");
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String query = sb.toString();
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XPathExpression expression3 = xpath.compile(query); // $hasXPathInjection
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isExist = (boolean) expression3.evaluate(doc, XPathConstants.BOOLEAN);
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System.out.println(isExist);
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// Good expression
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String expression4 = "/users/user[@name=$user and @pass=$pass]";
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xpath.setXPathVariableResolver(v -> {
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switch (v.getLocalPart()) {
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case "user":
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return user;
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case "pass":
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return pass;
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default:
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throw new IllegalArgumentException();
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}
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});
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isExist = (boolean) xpath.evaluate(expression4, doc, XPathConstants.BOOLEAN);
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System.out.println(isExist);
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// Bad Dom4j
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org.dom4j.io.SAXReader reader = new org.dom4j.io.SAXReader();
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org.dom4j.Document document = reader.read(new ByteArrayInputStream(xmlStr.getBytes()));
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isExist = document.selectSingleNode("/users/user[@name='" + user + "' and @pass='" + pass + "']") // $hasXPathInjection
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.hasContent();
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document.selectNodes("/users/user[@name='" + user + "' and @pass='" + pass + "']"); // $hasXPathInjection
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}
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}
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}

‎java/ql/test/experimental/query-tests/security/CWE-643/XPathInjectionTest.expected‎

Whitespace-only changes.

‎java/ql/test/experimental/query-tests/security/CWE-643/XPathInjectionTest.ql‎

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import java
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import semmle.code.java.dataflow.TaintTracking
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import semmle.code.java.dataflow.FlowSources
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import semmle.code.java.security.XPath
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import TestUtilities.InlineExpectationsTest
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class HasXPathInjectionTest extends InlineExpectationsTest {
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HasXPathInjectionTest() { this = "HasXPathInjectionTest" }
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override string getARelevantTag() { result = "hasXPathInjection" }
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override predicate hasActualResult(Location location, string element, string tag, string value) {
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tag = "hasXPathInjection" and
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exists(DataFlow::Node src, DataFlow::Node sink, XPathInjectionConfiguration conf |
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conf.hasFlow(src, sink)
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|
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sink.getLocation() = location and
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element = sink.toString() and
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value = ""
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)
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}
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}

‎java/ql/test/experimental/query-tests/security/CWE-643/options‎

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//semmle-extractor-options: --javac-args -cp ${testdir}/../../../../stubs/dom4j-2.1.1:${testdir}/../../../../stubs/servlet-api-2.4

‎java/ql/test/stubs/dom4j-2.1.1/org/dom4j/Document.java‎

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package org.dom4j;
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import java.util.List;
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public interface Document {
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public Node selectSingleNode(String xpathExpression);
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public List selectNodes(String xpathExpression);
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}
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/*

‎java/ql/test/stubs/dom4j-2.1.1/org/dom4j/Node.java‎

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/*
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* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
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*
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* This software is open source.
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* See the bottom of this file for the licence.
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*/
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/*
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* Adapted from DOM4J version 2.1.1 as available at
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* https://search.maven.org/remotecontent?filepath=org/dom4j/dom4j/2.1.1/dom4j-2.1.1-sources.jar
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* Only relevant stubs of this file have been retained for test purposes.
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*/
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package org.dom4j;
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public interface Node {
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public boolean hasContent();
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}
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/*
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* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
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*
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* This software is open source. See the bottom of this file for the licence.
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*/
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/*
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* Adapted from DOM4J version 2.1.1 as available at
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* https://search.maven.org/remotecontent?filepath=org/dom4j/dom4j/2.1.1/dom4j-2
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* .1.1-sources.jar Only relevant stubs of this file have been retained for test
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* purposes.
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*/

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