/*
* fb-contrib - Auxiliary detectors for Java programs
* Copyright (C) 2005-2017 Dave Brosius
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.mebigfatguy.fbcontrib.detect;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import com.mebigfatguy.fbcontrib.utils.BugType;
import com.mebigfatguy.fbcontrib.utils.RegisterUtils;
import com.mebigfatguy.fbcontrib.utils.SignatureBuilder;
import com.mebigfatguy.fbcontrib.utils.SignatureUtils;
import com.mebigfatguy.fbcontrib.utils.TernaryPatcher;
import com.mebigfatguy.fbcontrib.utils.UnmodifiableSet;
import com.mebigfatguy.fbcontrib.utils.Values;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.OpcodeStack;
import edu.umd.cs.findbugs.OpcodeStack.CustomUserValue;
import edu.umd.cs.findbugs.ba.ClassContext;
/**
* looks for method calls through reflection on methods found in java.lang.Object. As these methods are always available, there's no reason to do this.
*/
@CustomUserValue
public class ReflectionOnObjectMethods extends BytecodeScanningDetector {
public static final String SIG_STRING_AND_CLASS_ARRAY_TO_METHOD = new SignatureBuilder().withParamTypes(Values.SLASHED_JAVA_LANG_STRING, SignatureUtils.toArraySignature(Values.SLASHED_JAVA_LANG_CLASS))
.withReturnType(Method.class).toString();
private static final Set<String> objectSigs = UnmodifiableSet.create(
// "clone()", // clone is declared protected
"equals(Ljava/lang/Object;)", "finalize()", "getClass()", "hashCode()", "notify()", "notifyAll()", "toString()", "wait", "wait(J)", "wait(JI)");
private final BugReporter bugReporter;
private OpcodeStack stack;
private Map<Integer, String[]> localClassTypes;
private Map<String, String[]> fieldClassTypes;
/** This object is not thread-safe, but can be reused, provided that all necessary fields are overwritten. */
private final SignatureBuilder sigWithoutReturn = new SignatureBuilder().withoutReturnType();
/**
* constructs a ROOM detector given the reporter to report bugs on
*
* @param bugReporter
* the sync of bug reports
*/
public ReflectionOnObjectMethods(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
/**
* implements the visitor to create the stack and local and field maps for Class arrays to be used for getting the reflection method
*
* @param classContext
* the context object of the currently parse class
*/
@Override
public void visitClassContext(ClassContext classContext) {
try {
stack = new OpcodeStack();
localClassTypes = new HashMap<Integer, String[]>();
fieldClassTypes = new HashMap<String, String[]>();
JavaClass cls = classContext.getJavaClass();
Method staticInit = findStaticInitializer(cls);
if (staticInit != null) {
setupVisitorForClass(cls);
doVisitMethod(staticInit);
}
super.visitClassContext(classContext);
} finally {
stack = null;
localClassTypes = null;
fieldClassTypes = null;
}
}
/**
* implements the visitor to reset the opcode stack and clear the local variable map@
*
* @param obj
* the context object of the currently parsed code block
*/
@Override
public void visitCode(Code obj) {
stack.resetForMethodEntry(this);
localClassTypes.clear();
super.visitCode(obj);
}
/**
* implements the visitor to look for calls that invoke a method through reflection where the method is defined in java.lang.Object
*
* @param seen
* the currently parsed opcode
*/
@Override
public void sawOpcode(int seen) {
Integer arraySize = null;
String[] loadedTypes = null;
try {
stack.precomputation(this);
switch (seen) {
case ANEWARRAY: {
if (Values.SLASHED_JAVA_LANG_CLASS.equals(getClassConstantOperand()) && (stack.getStackDepth() >= 1)) {
OpcodeStack.Item item = stack.getStackItem(0);
arraySize = (Integer) item.getConstant();
}
}
break;
case AASTORE: {
if (stack.getStackDepth() >= 3) {
OpcodeStack.Item arrayItem = stack.getStackItem(2);
String[] arrayTypes = (String[]) arrayItem.getUserValue();
if (arrayTypes != null) {
OpcodeStack.Item valueItem = stack.getStackItem(0);
String type = (String) valueItem.getConstant();
if (type != null) {
OpcodeStack.Item indexItem = stack.getStackItem(1);
Integer index = (Integer) indexItem.getConstant();
if (index != null) {
arrayTypes[index.intValue()] = type;
}
}
}
}
}
break;
case PUTFIELD:
case PUTSTATIC: {
String name = getNameConstantOperand();
if (stack.getStackDepth() >= 1) {
OpcodeStack.Item item = stack.getStackItem(0);
String[] arrayTypes = (String[]) item.getUserValue();
if (arrayTypes != null) {
fieldClassTypes.put(name, arrayTypes);
return;
}
}
fieldClassTypes.remove(name);
}
break;
case GETFIELD:
case GETSTATIC: {
String name = getNameConstantOperand();
loadedTypes = fieldClassTypes.get(name);
}
break;
case ASTORE_0:
case ASTORE_1:
case ASTORE_2:
case ASTORE_3:
case ASTORE: {
Integer reg = Integer.valueOf(RegisterUtils.getAStoreReg(this, seen));
if (stack.getStackDepth() >= 1) {
OpcodeStack.Item item = stack.getStackItem(0);
String[] arrayTypes = (String[]) item.getUserValue();
if (arrayTypes != null) {
localClassTypes.put(reg, arrayTypes);
return;
}
}
localClassTypes.remove(reg);
}
break;
case ALOAD_0:
case ALOAD_1:
case ALOAD_2:
case ALOAD_3:
case ALOAD: {
int reg = RegisterUtils.getAStoreReg(this, seen);
loadedTypes = localClassTypes.get(Integer.valueOf(reg));
}
break;
case INVOKEVIRTUAL: {
String cls = getClassConstantOperand();
if (Values.SLASHED_JAVA_LANG_CLASS.equals(cls)) {
String method = getNameConstantOperand();
if ("getMethod".equals(method)) {
String sig = getSigConstantOperand();
if (SIG_STRING_AND_CLASS_ARRAY_TO_METHOD.equals(sig) && (stack.getStackDepth() >= 2)) {
OpcodeStack.Item clsArgs = stack.getStackItem(0);
String[] arrayTypes = (String[]) clsArgs.getUserValue();
if ((arrayTypes != null) || clsArgs.isNull()) {
OpcodeStack.Item methodItem = stack.getStackItem(1);
String methodName = (String) methodItem.getConstant();
if (methodName != null) {
String reflectionSig = sigWithoutReturn.withMethodName(methodName).withParamTypes(arrayTypes).build();
if (objectSigs.contains(reflectionSig)) {
loadedTypes = (arrayTypes == null) ? new String[0] : arrayTypes;
}
}
}
}
}
} else if ("java/lang/reflect/Method".equals(cls)) {
String method = getNameConstantOperand();
if ("invoke".equals(method) && (stack.getStackDepth() >= 3)) {
OpcodeStack.Item methodItem = stack.getStackItem(2);
String[] arrayTypes = (String[]) methodItem.getUserValue();
if (arrayTypes != null) {
bugReporter.reportBug(new BugInstance(this, BugType.ROOM_REFLECTION_ON_OBJECT_METHODS.name(), NORMAL_PRIORITY).addClass(this)
.addMethod(this).addSourceLine(this));
}
}
}
}
break;
default:
break;
}
} finally {
TernaryPatcher.pre(stack, seen);
stack.sawOpcode(this, seen);
TernaryPatcher.post(stack, seen);
if (stack.getStackDepth() >= 1) {
if (arraySize != null) {
OpcodeStack.Item item = stack.getStackItem(0);
item.setUserValue(new String[arraySize.intValue()]);
} else if (loadedTypes != null) {
OpcodeStack.Item item = stack.getStackItem(0);
item.setUserValue(loadedTypes);
}
}
}
}
/**
* finds the method that is the static initializer for the class
*
* @param cls
* the class to find the initializer for
*
* @return the Method of the static initializer or null if this class has none
*/
private static Method findStaticInitializer(JavaClass cls) {
Method[] methods = cls.getMethods();
for (Method m : methods) {
if (Values.STATIC_INITIALIZER.equals(m.getName())) {
return m;
}
}
return null;
}
}