上篇文章用一个简单的规则举例，帮助大家快速了解如何自定义规则。接下来我们开始使用更为复杂的例子进行实践。
我还是以自定义规则的思路逐步讲解，但是不会和上篇一样解释的非常详细，很多细节希望大家能够进行思考后获得恍然大悟的感觉：
需要自定义的规则大多来自开发的需求。这次举例的规则是：
Log 日志文件中不要输出敏感信息。根据过往的代码样本总结出可定义为敏感信息的字段包括：
- pid
- uid
- imei
- classname
- getLocalClassName
- getPackageCodePath
- getPackagePath
- android.os.Process.myPid
- android.os.Process.myUid
- android.os.Process.getUidForName
其中有些是字符串，有些是获取特定字段的方法，所涉及的主要是手机相关信息、类名、代码路径等。
错误样例的代码：
public class TestLog{
static Logger Log = Logger.getLogger("log");
static boolean DEBUG = true;
static boolean DEBUG1 = false;
public static void main(String []args){
Context cont = activity.getApplicationContext();
String classname = activity.getLocalClassName();
String pcodeName = cont.getPackageCodePath();
int id= android.os.Process.myPid();
String pid =String.valueOf(id);
int uicd= android.os.Process.myUid();
String uid = String.valueOf(uicd);
int idname= android.os.Process.getUidForName("pay");
String imei = ((TelephonyManager)getSystemService(TELEPHONY_SERVICE)).getDeviceId();
int bbq=activity.getLocalClassName();
Log.i("classname", classname);//触发规则
Log.i("pcodeName", pcodeName);//触发规则
Log.i("pid", pid);//触发规则
Log.i("uid", uid);//触发规则
Log.i("imei", imei); //触发规则
Log.i("imei", imei.length);
Log.i("imei", imei.size());
Log.i("imei:", activity.getLocalClassName());//触发规则
Log.i("imei:", MYUUID);
Log.i("imei:", imei.toString());//触发规则
Log.i("imei:", ab.imei.toString());//触发规则
Log.i("imei:", bbq);//触发规则
Log.i("imei:", idname);//触发规则
Log.i("imei:", id);//触发规则
Log.i("imei:", uicd);//触发规则
Log.i("imei:", pcodeName);//触发规则
Log.i("imei:", 101);
if (DEBUG) {
Log.i("imei", imei);//触发规则
}
if (DEBUG1) {
Log.i("imei", imei);
}
}
}
我在代码中标记出了触发规则的代码，大家可以根据代码前后文理解这些代码语句输出了什么敏感信息。
在语法树分析阶段，就得把这些触发错误的各种代码进行归类。
a. 在日志中直接输出敏感信息字符串。
b. 日志中直接输出敏感信息字符串做了处理。
c. 日志中输出的变量在前文中被赋值敏感信息。
d. 日志被日志开关包裹，开关为 true 时，才会输出敏感信息。
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.jaxen.JaxenException;
import net.sourceforge.pmd.lang.ast.Node;
import net.sourceforge.pmd.lang.java.ast.ASTBlock;
import net.sourceforge.pmd.lang.java.ast.ASTBlockStatement;
import net.sourceforge.pmd.lang.java.ast.ASTBooleanLiteral;
import net.sourceforge.pmd.lang.java.ast.ASTCompilationUnit;
import net.sourceforge.pmd.lang.java.ast.ASTExpression;
import net.sourceforge.pmd.lang.java.ast.ASTIfStatement;
import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
import net.sourceforge.pmd.lang.java.ast.ASTName;
import net.sourceforge.pmd.lang.java.ast.ASTPrimaryPrefix;
import net.sourceforge.pmd.lang.java.ast.ASTStatementExpression;
import net.sourceforge.pmd.lang.java.ast.ASTUnaryExpressionNotPlusMinus;
import net.sourceforge.pmd.lang.java.ast.ASTVariableDeclarator;
import net.sourceforge.pmd.lang.java.ast.ASTVariableDeclaratorId;
import net.sourceforge.pmd.lang.java.ast.ASTVariableInitializer;
import net.sourceforge.pmd.lang.java.rule.AbstractJavaRule;
/**
* @author yuanwei
* @date 2017年07月06日
* @category log中敏感信息泄露检测
*/
public class LogBlockRule extends AbstractJavaRule {
private static Set<String> SensitiveStrings = new HashSet<String>();
private List<ASTName> astNamewithLog =(List<ASTName>)new ArrayList<ASTName>();
private List<ASTName> SASTNames =(List<ASTName>)new ArrayList<ASTName>();
private List<ASTVariableDeclaratorId> SensitiveFieldVariables =(List<ASTVariableDeclaratorId>)new ArrayList<ASTVariableDeclaratorId>();
private List<String> BooleanTrueStrings=new ArrayList<String>();
private List<String> BooleanFalseStrings=new ArrayList<String>();
static {
SensitiveStrings.add("classname");
SensitiveStrings.add("pid");
SensitiveStrings.add("uid");
SensitiveStrings.add("imei");
SensitiveStrings.add("getLocalClassName");
SensitiveStrings.add("getPackagePath");
SensitiveStrings.add("android.os.Process.myPid");
SensitiveStrings.add("android.os.Process.myUid");
SensitiveStrings.add("android.os.Process.getUidForName");
}
@Override
public Object visit(ASTCompilationUnit node, Object data) {
startInitData(node);//初始化数据
checkLogRule(node,data);
return super.visit(node, data);
}
@SuppressWarnings("unchecked")
private void checkLogRule(Node node,Object data) {
if(!this.astNamewithLog.isEmpty()){
try {
List<ASTName> xpathLogNames = this.astNamewithLog; //将过滤以后的ASTname节点赋值给它，不再使用xpath
if(xpathLogNames.size()>0){
for(ASTName name:xpathLogNames){
ASTIfStatement ifStatement=name.getFirstParentOfType(ASTIfStatement.class);
ASTBlockStatement blockStatement=name.getFirstParentOfType(ASTBlockStatement.class);
List<ASTName> names2=(List<ASTName>) blockStatement.findDescendantsOfType(ASTName.class);
if(names2.size()>0){
for(ASTName name2:names2){
String imageString2=name2.getImage();
boolean sflag=checkIsSensitiveString(imageString2);
//当前没发现包含敏感信息，把该ASTName节点存储后续解析
if (!sflag) {
this.SASTNames.add(name2);
}
//当前发现包含敏感信息，确认是否被if包围
if (sflag) {
//被if判断包围，确认判断条件是否为true
if(ifStatement!=null){
if (checkConditionTrue(ifStatement)) {
addViolation(data, name2);
}
}
//没有被if判断包围，判断是否在执行到敏感信息语句前return
if (ifStatement==null) {
Boolean returnFlag=checkIfReturnStatement(name2);
//没有在之前return，触发规则
if (!returnFlag) {
addViolation(data, name2);
}
}
}
}
}
}
//新增第二层敏感信息监测
secendCheckLog(node,data);
}
}finally{
this.astNamewithLog.clear();
this.SASTNames.clear();
this.BooleanTrueStrings.clear();
this.BooleanFalseStrings.clear();
this.SensitiveFieldVariables.clear();
}
}
}
//新增第二层敏感信息监测
private void secendCheckLog(Node node, Object data) {
//先找出带有敏感信息的全局变量
try {
List<ASTVariableDeclaratorId> variableDeclaratorIds=(List<ASTVariableDeclaratorId>)node.findChildNodesWithXPath("//FieldDeclaration//VariableDeclarator/VariableDeclaratorId");
//检查ASTVariableDeclaratorId节点是否包含敏感信息
checkIsSensitiveFieldVariable(variableDeclaratorIds);
} catch (JaxenException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
//依次找出各个日志输出语句方法体内的变量
if (this.SASTNames.size()>0) {
for(ASTName SecondastName:this.SASTNames){
ASTMethodDeclaration astMethodDeclaration=SecondastName.getFirstParentOfType(ASTMethodDeclaration.class);
if (astMethodDeclaration==null) {
continue;
}
List<ASTVariableDeclaratorId> methodVariableDeclaratorIds=astMethodDeclaration.findDescendantsOfType(ASTVariableDeclaratorId.class);
List<ASTVariableDeclaratorId> SensitiveLocalVariables =
checkIsSensitiveLocalVariable(methodVariableDeclaratorIds);
if(this.SensitiveFieldVariables.size()>0){
checkSecondViolation(this.SensitiveFieldVariables,SecondastName,data);
}
if (SensitiveLocalVariables.size()>0) {
checkSecondViolation(SensitiveLocalVariables,SecondastName,data);
}
}
}
}
//检查带有敏感信息的变量有没有在日志中输出
private void checkSecondViolation(
List<ASTVariableDeclaratorId> sensitiveFieldVariables2,
ASTName secondastName, Object data) {
String astNameimage=secondastName.getImage();
for(ASTVariableDeclaratorId SensitiveVariable:sensitiveFieldVariables2){
if(!(hasNullInitializer(SensitiveVariable)) && astNameimage!=null&&SensitiveVariable.getImage().equalsIgnoreCase(astNameimage)){
//被if判断包围
ASTIfStatement ifStatement=secondastName.getFirstParentOfType(ASTIfStatement.class);
if(ifStatement!=null){
if (checkConditionTrue(ifStatement)) {
addViolation(data, secondastName);
}
}
//没有被if判断包围，判断是否在执行到敏感信息语句前return
if (ifStatement==null) {
Boolean returnFlag=checkIfReturnStatement(secondastName);
//没有在之前return，触发规则
if (!returnFlag) {
addViolation(data, secondastName);
}
}
}
}
}
//检查全局变量ASTVariableDeclaratorId节点是否包含敏感信息
private List<ASTVariableDeclaratorId> checkIsSensitiveLocalVariable(
List<ASTVariableDeclaratorId> methodVariableDeclaratorIds) {
List<ASTVariableDeclaratorId> SensitiveLocalVariables = (List<ASTVariableDeclaratorId>)new ArrayList<ASTVariableDeclaratorId>();
if (methodVariableDeclaratorIds.size()>0) {
for(ASTVariableDeclaratorId variableDeclaratorId:methodVariableDeclaratorIds){
if(variableDeclaratorId.jjtGetParent() instanceof ASTVariableDeclarator){
ASTName astName=variableDeclaratorId.getFirstParentOfType(ASTVariableDeclarator.class).getFirstDescendantOfType(ASTName.class);
if(astName!=null){
if (checkIsSensitiveString(astName.getImage())) {
SensitiveLocalVariables.add(variableDeclaratorId);
}
}
}
}
}
return SensitiveLocalVariables;
}
//检查本地变量ASTVariableDeclaratorId节点是否包含敏感信息
private void checkIsSensitiveFieldVariable(
List<ASTVariableDeclaratorId> variableDeclaratorIds) {
if (variableDeclaratorIds.size()>0) {
for(ASTVariableDeclaratorId variableDeclaratorId:variableDeclaratorIds){
if(variableDeclaratorId.jjtGetParent() instanceof ASTVariableDeclarator){
ASTName astName=variableDeclaratorId.getFirstParentOfType(ASTVariableDeclarator.class).getFirstDescendantOfType(ASTName.class);
if(astName!=null){
if (checkIsSensitiveString(astName.getImage())) {
this.SensitiveFieldVariables.add(variableDeclaratorId);
}
}
}
}
}
}
//判断if条件是否为true
private boolean checkConditionTrue(ASTIfStatement ifStatement) {
// TODO 自动生成的方法存根
ASTExpression astExpression=ifStatement.getFirstDescendantOfType(ASTExpression.class);
ASTName astName =astExpression.getFirstDescendantOfType(ASTName.class);
ASTUnaryExpressionNotPlusMinus astUENotPlusMinus=ifStatement.getFirstDescendantOfType(ASTUnaryExpressionNotPlusMinus.class);
if(astName!=null){
String astNameString=astName.getImage();
//存在非！符号时
if (astUENotPlusMinus!=null&&"!".equals(astUENotPlusMinus.getImage())) {
if(this.BooleanFalseStrings.size()>0 && this.BooleanFalseStrings.contains(astNameString)){
return true;
}
}else {
if(this.BooleanTrueStrings.size()>0 && this.BooleanTrueStrings.contains(astNameString)){
return true;
}
}
}
return false;
}
//初始化数据
private void startInitData(Node node) {
pickUpLogMethods(node); //遍历找出源代码中的Log.*代码
pickUpBooleanNames(node);//获取所有布尔型的值的名称
}
//获取所有布尔型的值的名称
private void pickUpBooleanNames(Node node) {
// TODO 自动生成的方法存根
String xpathBooleanTrue = ".//FieldDeclaration/VariableDeclarator/VariableInitializer/Expression/PrimaryExpression"
+"/PrimaryPrefix/Literal/BooleanLiteral[@True='true']";
String xpathBooleanFalse = ".//FieldDeclaration/VariableDeclarator/VariableInitializer/Expression/PrimaryExpression"
+"/PrimaryPrefix/Literal/BooleanLiteral[@True='false']";
List<ASTBooleanLiteral> xpathBooleanTrueNames;
List<ASTBooleanLiteral> xpathBooleanFalseNames;
try {
xpathBooleanTrueNames = (List<ASTBooleanLiteral>) node.findChildNodesWithXPath(xpathBooleanTrue);
if(xpathBooleanTrueNames.size()>0){
for(ASTBooleanLiteral booleanLiteral:xpathBooleanTrueNames){
ASTVariableDeclarator variableDeclarator = booleanLiteral.getFirstParentOfType(ASTVariableDeclarator.class);
ASTVariableDeclaratorId variableDeclaratorId = variableDeclarator.getFirstChildOfType(ASTVariableDeclaratorId.class);
this.BooleanTrueStrings.add(variableDeclaratorId.getImage());
}
}
xpathBooleanFalseNames = (List<ASTBooleanLiteral>) node.findChildNodesWithXPath(xpathBooleanFalse);
if(xpathBooleanFalseNames.size()>0){
for(ASTBooleanLiteral booleanLiteral:xpathBooleanFalseNames){
ASTVariableDeclarator variableDeclarator = booleanLiteral.getFirstParentOfType(ASTVariableDeclarator.class);
ASTVariableDeclaratorId variableDeclaratorId = variableDeclarator.getFirstChildOfType(ASTVariableDeclaratorId.class);
this.BooleanFalseStrings.add(variableDeclaratorId.getImage());
}
}
} catch (JaxenException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
}
// 检查是否在执行敏感信息输出语句前return
// 返回true说明使用了return语句在之前返回
private Boolean checkIfReturnStatement(ASTName name) {
int a = name.getEndLine();
//System.out.println("a="+a);
ASTMethodDeclaration astMethodDeclaration=name.getFirstParentOfType(ASTMethodDeclaration.class);
ASTBlock astBlock=astMethodDeclaration.getFirstChildOfType(ASTBlock.class);
List<Node> returnList;
try {
returnList = astBlock.findChildNodesWithXPath("//IfStatement//ReturnStatement");
if (returnList.size()>0) {
//System.out.println("returnList.size="+returnList.size());
for (Node node : returnList) {
int b=node.getEndLine();
//System.out.println("b="+b);
if (b<a) {
ASTIfStatement ifStatement=node.getFirstParentOfType(ASTIfStatement.class);
if (ifStatement!=null) {
if (checkConditionTrue(ifStatement)) {
return true;
}
}
}
}
}
} catch (JaxenException e) {
// TODO 自动生成的 catch 块
e.printStackTrace();
}
return false;
}
//判断是否包含敏感信息
private boolean checkIsSensitiveString(String imageString2) {
// TODO 自动生成的方法存根
for(String SensitiveString:SensitiveStrings){
if(imageString2.equalsIgnoreCase(SensitiveString)){
return true;
}
if (imageString2!=null&&imageString2.contains(".")) {
String[] partStrings=imageString2.split("\\.");
int LastIndex=partStrings.length-1;
if (partStrings[LastIndex].equals("length")||partStrings[LastIndex].equals("size")) {
return false;
}else {
for (int i = 0; i < partStrings.length; i++) {
String partString = partStrings[i];
if (partString.equalsIgnoreCase(SensitiveString)) {
return true;
}
}
}
}
}
return false;
}
//判断变量是否为null，如果初始化为null则剔除
private boolean hasNullInitializer(ASTVariableDeclaratorId var) {
ASTVariableInitializer init = var.getFirstDescendantOfType(ASTVariableInitializer.class);
if (init != null) {
try {
List<?> nulls = init.findChildNodesWithXPath("Expression/PrimaryExpression/PrimaryPrefix/Literal/NullLiteral");
return !nulls.isEmpty();
} catch (JaxenException e) {
return false;
}
}
return false;
}
//遍历找出源代码中的log.*代码
private void pickUpLogMethods(Node node){
List<ASTStatementExpression> pexs = node.findDescendantsOfType(ASTStatementExpression.class);
for(ASTStatementExpression ast : pexs){
ASTPrimaryPrefix primaryPrefix = ast.jjtGetChild(0).getFirstDescendantOfType(ASTPrimaryPrefix.class);
if (primaryPrefix != null) {
ASTName name = primaryPrefix.getFirstChildOfType(ASTName.class);
if (name != null) {
String imageString = name.getImage();
if(imageString.startsWith("Log.")){
astNamewithLog.add(name);
}
}
}
}
}
}
为了方便大家的理解，代码加了注释，但还是要结合第三点提出的四条特点进行理解。
同时我想说明一下，最深刻的理解在于动手实践，我上文提供的代码无需调试，可直接复制使用，希望大家在动手实践后能有自己的收获。
在上一篇文章中已经详细的介绍过，不再赘述。
特别需要注意的一点，规则完成后，使用样例代码验证只是确认自己撰写的逻辑是否正确。后续一定要经过大量实际代码扫描的验证，逐渐的提高规则的准确性，降低误报率。
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