Pass3aVerifier.java
/*
* 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.bcel.verifier.statics;
import java.util.Arrays;
import org.apache.bcel.Const;
import org.apache.bcel.Repository;
import org.apache.bcel.classfile.Attribute;
import org.apache.bcel.classfile.ClassFormatException;
import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.CodeException;
import org.apache.bcel.classfile.Constant;
import org.apache.bcel.classfile.ConstantCP;
import org.apache.bcel.classfile.ConstantClass;
import org.apache.bcel.classfile.ConstantDouble;
import org.apache.bcel.classfile.ConstantDynamic;
import org.apache.bcel.classfile.ConstantFieldref;
import org.apache.bcel.classfile.ConstantFloat;
import org.apache.bcel.classfile.ConstantInteger;
import org.apache.bcel.classfile.ConstantInterfaceMethodref;
import org.apache.bcel.classfile.ConstantInvokeDynamic;
import org.apache.bcel.classfile.ConstantLong;
import org.apache.bcel.classfile.ConstantMethodref;
import org.apache.bcel.classfile.ConstantNameAndType;
import org.apache.bcel.classfile.ConstantString;
import org.apache.bcel.classfile.ConstantUtf8;
import org.apache.bcel.classfile.Field;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.LineNumber;
import org.apache.bcel.classfile.LineNumberTable;
import org.apache.bcel.classfile.LocalVariableTable;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ANEWARRAY;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.ATHROW;
import org.apache.bcel.generic.ArrayType;
import org.apache.bcel.generic.BREAKPOINT;
import org.apache.bcel.generic.CHECKCAST;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.DLOAD;
import org.apache.bcel.generic.DSTORE;
import org.apache.bcel.generic.FLOAD;
import org.apache.bcel.generic.FSTORE;
import org.apache.bcel.generic.FieldInstruction;
import org.apache.bcel.generic.GETSTATIC;
import org.apache.bcel.generic.GotoInstruction;
import org.apache.bcel.generic.IINC;
import org.apache.bcel.generic.ILOAD;
import org.apache.bcel.generic.IMPDEP1;
import org.apache.bcel.generic.IMPDEP2;
import org.apache.bcel.generic.INSTANCEOF;
import org.apache.bcel.generic.INVOKEDYNAMIC;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKESPECIAL;
import org.apache.bcel.generic.INVOKESTATIC;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.ISTORE;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.InvokeInstruction;
import org.apache.bcel.generic.JsrInstruction;
import org.apache.bcel.generic.LDC;
import org.apache.bcel.generic.LDC2_W;
import org.apache.bcel.generic.LLOAD;
import org.apache.bcel.generic.LOOKUPSWITCH;
import org.apache.bcel.generic.LSTORE;
import org.apache.bcel.generic.LoadClass;
import org.apache.bcel.generic.MULTIANEWARRAY;
import org.apache.bcel.generic.NEW;
import org.apache.bcel.generic.NEWARRAY;
import org.apache.bcel.generic.ObjectType;
import org.apache.bcel.generic.PUTSTATIC;
import org.apache.bcel.generic.RET;
import org.apache.bcel.generic.ReferenceType;
import org.apache.bcel.generic.ReturnInstruction;
import org.apache.bcel.generic.TABLESWITCH;
import org.apache.bcel.generic.Type;
import org.apache.bcel.verifier.PassVerifier;
import org.apache.bcel.verifier.VerificationResult;
import org.apache.bcel.verifier.Verifier;
import org.apache.bcel.verifier.VerifierFactory;
import org.apache.bcel.verifier.exc.AssertionViolatedException;
import org.apache.bcel.verifier.exc.ClassConstraintException;
import org.apache.bcel.verifier.exc.InvalidMethodException;
import org.apache.bcel.verifier.exc.StaticCodeConstraintException;
import org.apache.bcel.verifier.exc.StaticCodeInstructionConstraintException;
import org.apache.bcel.verifier.exc.StaticCodeInstructionOperandConstraintException;
/**
* This PassVerifier verifies a class file according to pass 3, static part as described in The Java Virtual Machine
* Specification, 2nd edition. More detailed information is to be found at the do_verify() method's documentation.
*
* @see #do_verify()
*/
public final class Pass3aVerifier extends PassVerifier {
/**
* This visitor class does the actual checking for the instruction operand's constraints.
*/
private final class InstOperandConstraintVisitor extends org.apache.bcel.generic.EmptyVisitor {
/** The ConstantPoolGen instance this Visitor operates on. */
private final ConstantPoolGen constantPoolGen;
/** The only Constructor. */
InstOperandConstraintVisitor(final ConstantPoolGen constantPoolGen) {
this.constantPoolGen = constantPoolGen;
}
/**
* A utility method to always raise an exception.
*/
private void constraintViolated(final Instruction i, final String message) {
throw new StaticCodeInstructionOperandConstraintException("Instruction " + tostring(i) + " constraint violated: " + message);
}
/**
* Looks for the method referenced by the given invoke instruction in the given class.
*
* @param jc the class that defines the referenced method
* @param invoke the instruction that references the method
* @return the referenced method or null if not found.
*/
private Method getMethod(final JavaClass jc, final InvokeInstruction invoke) {
final Method[] ms = jc.getMethods();
for (final Method element : ms) {
if (element.getName().equals(invoke.getMethodName(constantPoolGen))
&& Type.getReturnType(element.getSignature()).equals(invoke.getReturnType(constantPoolGen))
&& Arrays.equals(Type.getArgumentTypes(element.getSignature()), invoke.getArgumentTypes(constantPoolGen))) {
return element;
}
}
return null;
}
/**
* Looks for the method referenced by the given invoke instruction in the given class or its super classes and super
* interfaces.
*
* @param jc the class that defines the referenced method
* @param invoke the instruction that references the method
* @return the referenced method or null if not found.
*/
private Method getMethodRecursive(final JavaClass jc, final InvokeInstruction invoke) throws ClassNotFoundException {
Method m;
// look in the given class
m = getMethod(jc, invoke);
if (m != null) {
// method found in given class
return m;
}
// method not found, look in super classes
for (final JavaClass superclass : jc.getSuperClasses()) {
m = getMethod(superclass, invoke);
if (m != null) {
// method found in super class
return m;
}
}
// method not found, look in super interfaces
for (final JavaClass superclass : jc.getInterfaces()) {
m = getMethod(superclass, invoke);
if (m != null) {
// method found in super interface
return m;
}
}
// method not found in the hierarchy
return null;
}
private ObjectType getObjectType(final FieldInstruction o) {
final ReferenceType rt = o.getReferenceType(constantPoolGen);
if (rt instanceof ObjectType) {
return (ObjectType) rt;
}
constraintViolated(o, "expecting ObjectType but got " + rt);
return null;
}
// The target of each jump and branch instruction [...] must be the opcode [...]
// BCEL _DOES_ handle this.
// tableswitch: BCEL will do it, supposedly.
// lookupswitch: BCEL will do it, supposedly.
/**
* A utility method to raise an exception if the index is not a valid constant pool index.
*/
private void indexValid(final Instruction i, final int idx) {
if (idx < 0 || idx >= constantPoolGen.getSize()) {
constraintViolated(i, "Illegal constant pool index '" + idx + "'.");
}
}
/**
* Utility method to return the max_locals value of the method verified by the surrounding Pass3aVerifier instance.
*/
private int maxLocals() {
try {
return Repository.lookupClass(verifier.getClassName()).getMethods()[methodNo].getCode().getMaxLocals();
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitALOAD(final ALOAD o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitANEWARRAY(final ANEWARRAY o) {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantClass)) {
constraintViolated(o, "Expecting a CONSTANT_Class operand, but found a '" + tostring(c) + "'.");
}
final Type t = o.getType(constantPoolGen);
if (t instanceof ArrayType) {
final int dimensions = ((ArrayType) t).getDimensions();
if (dimensions > Const.MAX_ARRAY_DIMENSIONS) {
constraintViolated(o,
"Not allowed to create an array with more than " + Const.MAX_ARRAY_DIMENSIONS + " dimensions;" + " actual: " + dimensions);
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitASTORE(final ASTORE o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitCHECKCAST(final CHECKCAST o) {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantClass)) {
constraintViolated(o, "Expecting a CONSTANT_Class operand, but found a '" + tostring(c) + "'.");
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitDLOAD(final DLOAD o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative."
+ " [Constraint by JustIce as an analogon to the single-slot xLOAD/xSTORE instructions; may not happen anyway.]");
} else {
final int maxminus2 = maxLocals() - 2;
if (idx > maxminus2) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-2 '" + maxminus2 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitDSTORE(final DSTORE o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative."
+ " [Constraint by JustIce as an analogon to the single-slot xLOAD/xSTORE instructions; may not happen anyway.]");
} else {
final int maxminus2 = maxLocals() - 2;
if (idx > maxminus2) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-2 '" + maxminus2 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
// getfield, putfield, getstatic, putstatic
@Override
public void visitFieldInstruction(final FieldInstruction o) {
try {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantFieldref)) {
constraintViolated(o, "Indexing a constant that's not a CONSTANT_Fieldref but a '" + tostring(c) + "'.");
}
final String fieldName = o.getFieldName(constantPoolGen);
final JavaClass jc = Repository.lookupClass(getObjectType(o).getClassName());
final Field f = jc.findField(fieldName, o.getType(constantPoolGen));
if (f == null) {
constraintViolated(o, "Referenced field '" + fieldName + "' does not exist in class '" + jc.getClassName() + "'.");
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitFLOAD(final FLOAD o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitFSTORE(final FSTORE o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitGETSTATIC(final GETSTATIC o) {
try {
final String fieldName = o.getFieldName(constantPoolGen);
final JavaClass jc = Repository.lookupClass(getObjectType(o).getClassName());
final Field f = jc.findField(fieldName, o.getType(constantPoolGen));
if (f == null) {
throw new AssertionViolatedException("Field '" + fieldName + "' not found in " + jc.getClassName());
}
if (!f.isStatic()) {
constraintViolated(o, "Referenced field '" + f + "' is not static which it should be.");
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitIINC(final IINC o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitILOAD(final ILOAD o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINSTANCEOF(final INSTANCEOF o) {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantClass)) {
constraintViolated(o, "Expecting a CONSTANT_Class operand, but found a '" + tostring(c) + "'.");
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINVOKEDYNAMIC(final INVOKEDYNAMIC o) {
throw new UnsupportedOperationException("INVOKEDYNAMIC instruction is not supported at this time");
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitInvokeInstruction(final InvokeInstruction o) {
indexValid(o, o.getIndex());
if (o instanceof INVOKEVIRTUAL || o instanceof INVOKESPECIAL || o instanceof INVOKESTATIC) {
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantMethodref)) {
constraintViolated(o, "Indexing a constant that's not a CONSTANT_Methodref but a '" + tostring(c) + "'.");
} else {
// Constants are okay due to pass2.
final ConstantNameAndType cnat = (ConstantNameAndType) constantPoolGen.getConstant(((ConstantMethodref) c).getNameAndTypeIndex());
final ConstantUtf8 cutf8 = (ConstantUtf8) constantPoolGen.getConstant(cnat.getNameIndex());
if (cutf8.getBytes().equals(Const.CONSTRUCTOR_NAME) && !(o instanceof INVOKESPECIAL)) {
constraintViolated(o, "Only INVOKESPECIAL is allowed to invoke instance initialization methods.");
}
if (!cutf8.getBytes().equals(Const.CONSTRUCTOR_NAME) && cutf8.getBytes().startsWith("<")) {
constraintViolated(o, "No method with a name beginning with '<' other than the instance initialization methods"
+ " may be called by the method invocation instructions.");
}
}
} else {
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantInterfaceMethodref) && !(c instanceof ConstantInvokeDynamic)) {
constraintViolated(o, "Indexing a constant that's not a CONSTANT_InterfaceMethodref/InvokeDynamic but a '" + tostring(c) + "'.");
}
// TODO: From time to time check if BCEL allows to detect if the
// 'count' operand is consistent with the information in the
// CONSTANT_InterfaceMethodref and if the last operand is zero.
// By now, BCEL hides those two operands because they're superfluous.
// Invoked method must not be <init> or <clinit>
final ConstantNameAndType cnat = (ConstantNameAndType) constantPoolGen.getConstant(((ConstantCP) c).getNameAndTypeIndex());
final String name = ((ConstantUtf8) constantPoolGen.getConstant(cnat.getNameIndex())).getBytes();
if (name.equals(Const.CONSTRUCTOR_NAME)) {
constraintViolated(o, "Method to invoke must not be '" + Const.CONSTRUCTOR_NAME + "'.");
}
if (name.equals(Const.STATIC_INITIALIZER_NAME)) {
constraintViolated(o, "Method to invoke must not be '" + Const.STATIC_INITIALIZER_NAME + "'.");
}
}
// The LoadClassType is the method-declaring class, so we have to check the other types.
Type t = o.getReturnType(constantPoolGen);
if (t instanceof ArrayType) {
t = ((ArrayType) t).getBasicType();
}
if (t instanceof ObjectType) {
final Verifier v = VerifierFactory.getVerifier(((ObjectType) t).getClassName());
final VerificationResult vr = v.doPass2();
if (vr.getStatus() != VerificationResult.VERIFIED_OK) {
constraintViolated(o, "Return type class/interface could not be verified successfully: '" + vr.getMessage() + "'.");
}
}
final Type[] ts = o.getArgumentTypes(constantPoolGen);
for (final Type element : ts) {
t = element;
if (t instanceof ArrayType) {
t = ((ArrayType) t).getBasicType();
}
if (t instanceof ObjectType) {
final Verifier v = VerifierFactory.getVerifier(((ObjectType) t).getClassName());
final VerificationResult vr = v.doPass2();
if (vr.getStatus() != VerificationResult.VERIFIED_OK) {
constraintViolated(o, "Argument type class/interface could not be verified successfully: '" + vr.getMessage() + "'.");
}
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINVOKEINTERFACE(final INVOKEINTERFACE o) {
try {
// INVOKEINTERFACE is a LoadClass; the Class where the referenced method is declared in,
// is therefore resolved/verified.
// INVOKEINTERFACE is an InvokeInstruction, the argument and return types are resolved/verified,
// too. So are the allowed method names.
final String className = o.getClassName(constantPoolGen);
final JavaClass jc = Repository.lookupClass(className);
final Method m = getMethodRecursive(jc, o);
if (m == null) {
constraintViolated(o, "Referenced method '" + o.getMethodName(constantPoolGen) + "' with expected signature '"
+ o.getSignature(constantPoolGen) + "' not found in class '" + jc.getClassName() + "'.");
}
if (jc.isClass()) {
constraintViolated(o, "Referenced class '" + jc.getClassName() + "' is a class, but not an interface as expected.");
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINVOKESPECIAL(final INVOKESPECIAL o) {
try {
// INVOKESPECIAL is a LoadClass; the Class where the referenced method is declared in,
// is therefore resolved/verified.
// INVOKESPECIAL is an InvokeInstruction, the argument and return types are resolved/verified,
// too. So are the allowed method names.
final String className = o.getClassName(constantPoolGen);
final JavaClass jc = Repository.lookupClass(className);
final Method m = getMethodRecursive(jc, o);
if (m == null) {
constraintViolated(o, "Referenced method '" + o.getMethodName(constantPoolGen) + "' with expected signature '"
+ o.getSignature(constantPoolGen) + "' not found in class '" + jc.getClassName() + "'.");
}
JavaClass current = Repository.lookupClass(verifier.getClassName());
if (current.isSuper() && Repository.instanceOf(current, jc) && !current.equals(jc)
&& !o.getMethodName(constantPoolGen).equals(Const.CONSTRUCTOR_NAME)) {
// Special lookup procedure for ACC_SUPER classes.
int supidx = -1;
Method meth = null;
while (supidx != 0) {
supidx = current.getSuperclassNameIndex();
current = Repository.lookupClass(current.getSuperclassName());
final Method[] meths = current.getMethods();
for (final Method meth2 : meths) {
if (meth2.getName().equals(o.getMethodName(constantPoolGen))
&& Type.getReturnType(meth2.getSignature()).equals(o.getReturnType(constantPoolGen))
&& Arrays.equals(Type.getArgumentTypes(meth2.getSignature()), o.getArgumentTypes(constantPoolGen))) {
meth = meth2;
break;
}
}
if (meth != null) {
break;
}
}
if (meth == null) {
constraintViolated(o, "ACC_SUPER special lookup procedure not successful: method '" + o.getMethodName(constantPoolGen)
+ "' with proper signature not declared in superclass hierarchy.");
}
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINVOKESTATIC(final INVOKESTATIC o) {
try {
// INVOKESTATIC is a LoadClass; the Class where the referenced method is declared in,
// is therefore resolved/verified.
// INVOKESTATIC is an InvokeInstruction, the argument and return types are resolved/verified,
// too. So are the allowed method names.
final String className = o.getClassName(constantPoolGen);
final JavaClass jc = Repository.lookupClass(className);
final Method m = getMethodRecursive(jc, o);
if (m == null) {
constraintViolated(o, "Referenced method '" + o.getMethodName(constantPoolGen) + "' with expected signature '"
+ o.getSignature(constantPoolGen) + "' not found in class '" + jc.getClassName() + "'.");
} else if (!m.isStatic()) { // implies it's not abstract, verified in pass 2.
constraintViolated(o, "Referenced method '" + o.getMethodName(constantPoolGen) + "' has ACC_STATIC unset.");
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitINVOKEVIRTUAL(final INVOKEVIRTUAL o) {
try {
// INVOKEVIRTUAL is a LoadClass; the Class where the referenced method is declared in,
// is therefore resolved/verified.
// INVOKEVIRTUAL is an InvokeInstruction, the argument and return types are resolved/verified,
// too. So are the allowed method names.
final String className = o.getClassName(constantPoolGen);
JavaClass jc;
if (className.charAt(0) == '[') { // array type, e.g. invoke can be someArray.clone()
jc = Repository.lookupClass("java.lang.Object");
} else {
jc = Repository.lookupClass(className);
}
final Method m = getMethodRecursive(jc, o);
if (m == null) {
constraintViolated(o, "Referenced method '" + o.getMethodName(constantPoolGen) + "' with expected signature '"
+ o.getSignature(constantPoolGen) + "' not found in class '" + jc.getClassName() + "'.");
}
if (!jc.isClass()) {
constraintViolated(o, "Referenced class '" + jc.getClassName() + "' is an interface, but not a class as expected.");
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
// throw new AssertionViolatedException("Missing class: " + e, e);
addMessage("Unable to verify INVOKEVITUAL as cannot load target class: " + e.getCause());
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitISTORE(final ISTORE o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
// LDC and LDC_W (LDC_W is a subclass of LDC in BCEL's model)
@Override
public void visitLDC(final LDC ldc) {
indexValid(ldc, ldc.getIndex());
final Constant c = constantPoolGen.getConstant(ldc.getIndex());
if (c instanceof ConstantClass) {
addMessage("Operand of LDC or LDC_W is CONSTANT_Class '" + tostring(c) + "' - this is only supported in JDK 1.5 and higher.");
} else if (!(c instanceof ConstantInteger || c instanceof ConstantFloat || c instanceof ConstantString || c instanceof ConstantDynamic)) {
constraintViolated(ldc,
"Operand of LDC or LDC_W must be one of CONSTANT_Integer, CONSTANT_Float, CONSTANT_String or CONSTANT_Dynamic but is '"
+ tostring(c) + "'.");
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
// LDC2_W
@Override
public void visitLDC2_W(final LDC2_W o) {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantLong || c instanceof ConstantDouble)) {
constraintViolated(o, "Operand of LDC2_W must be CONSTANT_Long or CONSTANT_Double, but is '" + tostring(c) + "'.");
}
try {
indexValid(o, o.getIndex() + 1);
} catch (final StaticCodeInstructionOperandConstraintException e) {
throw new AssertionViolatedException("Does not BCEL handle that? LDC2_W operand has a problem.", e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitLLOAD(final LLOAD o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative."
+ " [Constraint by JustIce as an analogon to the single-slot xLOAD/xSTORE instructions; may not happen anyway.]");
} else {
final int maxminus2 = maxLocals() - 2;
if (idx > maxminus2) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-2 '" + maxminus2 + "'.");
}
}
}
///////////////////////////////////////////////////////////
// The Java Virtual Machine Specification, pages 134-137 //
///////////////////////////////////////////////////////////
/**
* Assures the generic preconditions of a LoadClass instance. The referenced class is loaded and pass2-verified.
*/
@Override
public void visitLoadClass(final LoadClass loadClass) {
final ObjectType t = loadClass.getLoadClassType(constantPoolGen);
if (t != null) { // null means "no class is loaded"
final Verifier v = VerifierFactory.getVerifier(t.getClassName());
final VerificationResult vr = v.doPass1();
if (vr.getStatus() != VerificationResult.VERIFIED_OK) {
constraintViolated((Instruction) loadClass,
"Class '" + loadClass.getLoadClassType(constantPoolGen).getClassName() + "' is referenced, but cannot be loaded: '" + vr + "'.");
}
}
}
/* Checks if the constraints of operands of the said instruction(s) are satisfied. */
// public void visitPUTFIELD(PUTFIELD o) {
// for performance reasons done in Pass 3b
// }
/* Checks if the constraints of operands of the said instruction(s) are satisfied. */
// public void visitGETFIELD(GETFIELD o) {
// for performance reasons done in Pass 3b
// }
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitLOOKUPSWITCH(final LOOKUPSWITCH o) {
final int[] matchs = o.getMatchs();
int max = Integer.MIN_VALUE;
for (int i = 0; i < matchs.length; i++) {
if (matchs[i] == max && i != 0) {
constraintViolated(o, "Match '" + matchs[i] + "' occurs more than once.");
}
if (matchs[i] < max) {
constraintViolated(o, "Lookup table must be sorted but isn't.");
} else {
max = matchs[i];
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitLSTORE(final LSTORE o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative."
+ " [Constraint by JustIce as an analogon to the single-slot xLOAD/xSTORE instructions; may not happen anyway.]");
} else {
final int maxminus2 = maxLocals() - 2;
if (idx > maxminus2) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-2 '" + maxminus2 + "'.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitMULTIANEWARRAY(final MULTIANEWARRAY o) {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantClass)) {
constraintViolated(o, "Expecting a CONSTANT_Class operand, but found a '" + tostring(c) + "'.");
}
final int dimensions2create = o.getDimensions();
if (dimensions2create < 1) {
constraintViolated(o, "Number of dimensions to create must be greater than zero.");
}
final Type t = o.getType(constantPoolGen);
if (t instanceof ArrayType) {
final int dimensions = ((ArrayType) t).getDimensions();
if (dimensions < dimensions2create) {
constraintViolated(o, "Not allowed to create array with more dimensions ('" + dimensions2create
+ "') than the one referenced by the CONSTANT_Class '" + t + "'.");
}
} else {
constraintViolated(o, "Expecting a CONSTANT_Class referencing an array type."
+ " [Constraint not found in The Java Virtual Machine Specification, Second Edition, 4.8.1]");
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitNEW(final NEW o) {
indexValid(o, o.getIndex());
final Constant c = constantPoolGen.getConstant(o.getIndex());
if (!(c instanceof ConstantClass)) {
constraintViolated(o, "Expecting a CONSTANT_Class operand, but found a '" + tostring(c) + "'.");
} else {
final ConstantUtf8 cutf8 = (ConstantUtf8) constantPoolGen.getConstant(((ConstantClass) c).getNameIndex());
final Type t = Type.getType("L" + cutf8.getBytes() + ";");
if (t instanceof ArrayType) {
constraintViolated(o, "NEW must not be used to create an array.");
}
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitNEWARRAY(final NEWARRAY o) {
final byte t = o.getTypecode();
if (!(t == Const.T_BOOLEAN || t == Const.T_CHAR || t == Const.T_FLOAT || t == Const.T_DOUBLE || t == Const.T_BYTE || t == Const.T_SHORT
|| t == Const.T_INT || t == Const.T_LONG)) {
constraintViolated(o, "Illegal type code '" + tostring(t) + "' for 'atype' operand.");
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitPUTSTATIC(final PUTSTATIC o) {
try {
final String fieldName = o.getFieldName(constantPoolGen);
final JavaClass jc = Repository.lookupClass(getObjectType(o).getClassName());
final Field f = jc.findField(fieldName, o.getType(constantPoolGen));
if (f == null) {
throw new AssertionViolatedException("Field '" + fieldName + "' not found in " + jc.getClassName());
}
if (f.isFinal() && !verifier.getClassName().equals(getObjectType(o).getClassName())) {
constraintViolated(o, "Referenced field '" + f + "' is final and must therefore be declared in the current class '"
+ verifier.getClassName() + "' which is not the case: it is declared in '" + o.getReferenceType(constantPoolGen) + "'.");
}
if (!f.isStatic()) {
constraintViolated(o, "Referenced field '" + f + "' is not static which it should be.");
}
final String methName = Repository.lookupClass(verifier.getClassName()).getMethods()[methodNo].getName();
// If it's an interface, it can be set only in <clinit>.
if (!jc.isClass() && !methName.equals(Const.STATIC_INITIALIZER_NAME)) {
constraintViolated(o, "Interface field '" + f + "' must be set in a '" + Const.STATIC_INITIALIZER_NAME + "' method.");
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitRET(final RET o) {
final int idx = o.getIndex();
if (idx < 0) {
constraintViolated(o, "Index '" + idx + "' must be non-negative.");
} else {
final int maxminus1 = maxLocals() - 1;
if (idx > maxminus1) {
constraintViolated(o, "Index '" + idx + "' must not be greater than max_locals-1 '" + maxminus1 + "'.");
}
}
}
// WIDE stuff is BCEL-internal and cannot be checked here.
/** Checks if the constraints of operands of the said instruction(s) are satisfied. */
@Override
public void visitTABLESWITCH(final TABLESWITCH o) {
// "high" must be >= "low". We cannot check this, as BCEL hides
// it from us.
}
}
/** A small utility method returning if a given int i is in the given int[] ints. */
private static boolean contains(final int[] ints, final int i) {
for (final int k : ints) {
if (k == i) {
return true;
}
}
return false;
}
/** The Verifier that created this. */
private final Verifier verifier;
/**
* The method number to verify. This is the index in the array returned by JavaClass.getMethods().
*/
private final int methodNo;
/**
* The one and only InstructionList object used by an instance of this class. It's here for performance reasons by
* do_verify() and its callees.
*/
private InstructionList instructionList;
/**
* The one and only Code object used by an instance of this class. It's here for performance reasons by do_verify() and
* its callees.
*/
private Code code;
/** Should only be instantiated by a Verifier. */
public Pass3aVerifier(final Verifier verifier, final int methodNo) {
this.verifier = verifier;
this.methodNo = methodNo;
}
/**
* These are the checks that could be done in pass 2 but are delayed to pass 3 for performance reasons. Also, these
* checks need access to the code array of the Code attribute of a Method so it's okay to perform them here. Also see
* the description of the do_verify() method.
*
* @throws ClassConstraintException if the verification fails.
* @see #do_verify()
*/
private void delayedPass2Checks() {
final int[] instructionPositions = instructionList.getInstructionPositions();
final int codeLength = code.getCode().length;
/////////////////////
// LineNumberTable //
/////////////////////
final LineNumberTable lnt = code.getLineNumberTable();
if (lnt != null) {
final LineNumber[] lineNumbers = lnt.getLineNumberTable();
final IntList offsets = new IntList();
lineNumberLoop: for (final LineNumber lineNumber : lineNumbers) { // may appear in any order.
for (final int instructionPosition : instructionPositions) {
// TODO: Make this a binary search! The instructionPositions array is naturally ordered!
final int offset = lineNumber.getStartPC();
if (instructionPosition == offset) {
if (offsets.contains(offset)) {
addMessage("LineNumberTable attribute '" + code.getLineNumberTable() + "' refers to the same code offset ('" + offset
+ "') more than once" + " which is violating the semantics [but is sometimes produced by IBM's 'jikes' compiler].");
} else {
offsets.add(offset);
}
continue lineNumberLoop;
}
}
throw new ClassConstraintException("Code attribute '" + tostring(code) + "' has a LineNumberTable attribute '" + code.getLineNumberTable()
+ "' referring to a code offset ('" + lineNumber.getStartPC() + "') that does not exist.");
}
}
///////////////////////////
// LocalVariableTable(s) //
///////////////////////////
/*
* We cannot use code.getLocalVariableTable() because there could be more than only one. This is a bug in BCEL.
*/
final Attribute[] atts = code.getAttributes();
for (final Attribute att : atts) {
if (att instanceof LocalVariableTable) {
((LocalVariableTable) att).forEach(localVariable -> {
final int startpc = localVariable.getStartPC();
final int length = localVariable.getLength();
if (!contains(instructionPositions, startpc)) {
throw new ClassConstraintException("Code attribute '" + tostring(code) + "' has a LocalVariableTable attribute '"
+ code.getLocalVariableTable() + "' referring to a code offset ('" + startpc + "') that does not exist.");
}
if (!contains(instructionPositions, startpc + length) && startpc + length != codeLength) {
throw new ClassConstraintException(
"Code attribute '" + tostring(code) + "' has a LocalVariableTable attribute '" + code.getLocalVariableTable()
+ "' referring to a code offset start_pc+length ('" + (startpc + length) + "') that does not exist.");
}
});
}
}
////////////////////
// ExceptionTable //
////////////////////
// In BCEL's "classfile" API, the startPC/endPC-notation is
// inclusive/exclusive as in the Java Virtual Machine Specification.
// WARNING: This is not true for BCEL's "generic" API.
final CodeException[] exceptionTable = code.getExceptionTable();
for (final CodeException element : exceptionTable) {
final int startpc = element.getStartPC();
final int endpc = element.getEndPC();
final int handlerpc = element.getHandlerPC();
if (startpc >= endpc) {
throw new ClassConstraintException("Code attribute '" + tostring(code) + "' has an exception_table entry '" + element
+ "' that has its start_pc ('" + startpc + "') not smaller than its end_pc ('" + endpc + "').");
}
if (!contains(instructionPositions, startpc)) {
throw new ClassConstraintException("Code attribute '" + tostring(code) + "' has an exception_table entry '" + element
+ "' that has a non-existant bytecode offset as its start_pc ('" + startpc + "').");
}
if (!contains(instructionPositions, endpc) && endpc != codeLength) {
throw new ClassConstraintException("Code attribute '" + tostring(code) + "' has an exception_table entry '" + element
+ "' that has a non-existant bytecode offset as its end_pc ('" + startpc + "') [that is also not equal to code_length ('" + codeLength
+ "')].");
}
if (!contains(instructionPositions, handlerpc)) {
throw new ClassConstraintException("Code attribute '" + tostring(code) + "' has an exception_table entry '" + element
+ "' that has a non-existant bytecode offset as its handler_pc ('" + handlerpc + "').");
}
}
}
/**
* Pass 3a is the verification of static constraints of JVM code (such as legal targets of branch instructions). This is
* the part of pass 3 where you do not need data flow analysis. JustIce also delays the checks for a correct exception
* table of a Code attribute and correct line number entries in a LineNumberTable attribute of a Code attribute (which
* conceptually belong to pass 2) to this pass. Also, most of the check for valid local variable entries in a
* LocalVariableTable attribute of a Code attribute is delayed until this pass. All these checks need access to the code
* array of the Code attribute.
*
* @throws InvalidMethodException if the method to verify does not exist.
*/
@Override
public VerificationResult do_verify() {
try {
if (verifier.doPass2().equals(VerificationResult.VR_OK)) {
// Okay, class file was loaded correctly by Pass 1
// and satisfies static constraints of Pass 2.
final JavaClass jc = Repository.lookupClass(verifier.getClassName());
final Method[] methods = jc.getMethods();
if (methodNo >= methods.length) {
throw new InvalidMethodException("METHOD DOES NOT EXIST!");
}
final Method method = methods[methodNo];
code = method.getCode();
// No Code? Nothing to verify!
if (method.isAbstract() || method.isNative()) { // IF mg HAS NO CODE (static constraint of Pass 2)
return VerificationResult.VR_OK;
}
// TODO:
// We want a very sophisticated code examination here with good explanations
// on where to look for an illegal instruction or such.
// Only after that we should try to build an InstructionList and throw an
// AssertionViolatedException if after our examination InstructionList building
// still fails.
// That examination should be implemented in a byte-oriented way, i.e. look for
// an instruction, make sure its validity, count its length, find the next
// instruction and so on.
try {
instructionList = new InstructionList(method.getCode().getCode());
} catch (final RuntimeException re) {
return new VerificationResult(VerificationResult.VERIFIED_REJECTED,
"Bad bytecode in the code array of the Code attribute of method '" + tostring(method) + "'.");
}
instructionList.setPositions(true);
// Start verification.
VerificationResult vr = VerificationResult.VR_OK; // default
try {
delayedPass2Checks();
} catch (final ClassConstraintException | ClassFormatException cce) {
return new VerificationResult(VerificationResult.VERIFIED_REJECTED, cce.getMessage());
}
try {
pass3StaticInstructionChecks();
pass3StaticInstructionOperandsChecks();
} catch (final StaticCodeConstraintException | ClassFormatException scce) {
vr = new VerificationResult(VerificationResult.VERIFIED_REJECTED, scce.getMessage());
} catch (final ClassCastException cce) {
vr = new VerificationResult(VerificationResult.VERIFIED_REJECTED, "Class Cast Exception: " + cce.getMessage());
}
return vr;
}
// did not pass Pass 2.
return VerificationResult.VR_NOTYET;
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/** Returns the method number as supplied when instantiating. */
public int getMethodNo() {
return methodNo;
}
/**
* These are the checks if constraints are satisfied which are described in the Java Virtual Machine Specification,
* Second Edition as Static Constraints on the instructions of Java Virtual Machine Code (chapter 4.8.1).
*
* @throws StaticCodeConstraintException if the verification fails.
*/
private void pass3StaticInstructionChecks() {
// Code array must not be empty:
// Enforced in pass 2 (also stated in the static constraints of the Code
// array in vmspec2), together with pass 1 (reading code_length bytes and
// interpreting them as code[]). So this must not be checked again here.
if (code.getCode().length >= Const.MAX_CODE_SIZE) { // length must be LESS than the max
throw new StaticCodeInstructionConstraintException(
"Code array in code attribute '" + tostring(code) + "' too big: must be smaller than " + Const.MAX_CODE_SIZE + "65536 bytes.");
}
// First opcode at offset 0: okay, that's clear. Nothing to do.
// Only instances of the instructions documented in Section 6.4 may appear in
// the code array.
// For BCEL's sake, we cannot handle WIDE stuff, but hopefully BCEL does its job right :)
// The last byte of the last instruction in the code array must be the byte at index
// code_length-1 : See the do_verify() comments. We actually don't iterate through the
// byte array, but use an InstructionList so we cannot check for this. But BCEL does
// things right, so it's implicitly okay.
// TODO: Check how BCEL handles (and will handle) instructions like IMPDEP1, IMPDEP2,
// BREAKPOINT... that BCEL knows about but which are illegal anyway.
// We currently go the safe way here.
InstructionHandle ih = instructionList.getStart();
while (ih != null) {
final Instruction i = ih.getInstruction();
if (i instanceof IMPDEP1) {
throw new StaticCodeInstructionConstraintException("IMPDEP1 must not be in the code, it is an illegal instruction for _internal_ JVM use!");
}
if (i instanceof IMPDEP2) {
throw new StaticCodeInstructionConstraintException("IMPDEP2 must not be in the code, it is an illegal instruction for _internal_ JVM use!");
}
if (i instanceof BREAKPOINT) {
throw new StaticCodeInstructionConstraintException("BREAKPOINT must not be in the code, it is an illegal instruction for _internal_ JVM use!");
}
ih = ih.getNext();
}
// The original verifier seems to do this check here, too.
// An unreachable last instruction may also not fall through the
// end of the code, which is stupid -- but with the original
// verifier's subroutine semantics one cannot predict reachability.
final Instruction last = instructionList.getEnd().getInstruction();
if (!(last instanceof ReturnInstruction || last instanceof RET || last instanceof GotoInstruction || last instanceof ATHROW)) {
throw new StaticCodeInstructionConstraintException(
"Execution must not fall off the bottom of the code array." + " This constraint is enforced statically as some existing verifiers do"
+ " - so it may be a false alarm if the last instruction is not reachable.");
}
}
/**
* These are the checks for the satisfaction of constraints which are described in the Java Virtual Machine
* Specification, Second Edition as Static Constraints on the operands of instructions of Java Virtual Machine Code
* (chapter 4.8.1). BCEL parses the code array to create an InstructionList and therefore has to check some of these
* constraints. Additional checks are also implemented here.
*
* @throws StaticCodeConstraintException if the verification fails.
*/
private void pass3StaticInstructionOperandsChecks() {
try {
// When building up the InstructionList, BCEL has already done all those checks
// mentioned in The Java Virtual Machine Specification, Second Edition, as
// "static constraints on the operands of instructions in the code array".
// TODO: see the do_verify() comments. Maybe we should really work on the
// byte array first to give more comprehensive messages.
// TODO: Review Exception API, possibly build in some "offending instruction" thing
// when we're ready to insulate the offending instruction by doing the
// above thing.
// TODO: Implement as much as possible here. BCEL does _not_ check everything.
final ConstantPoolGen cpg = new ConstantPoolGen(Repository.lookupClass(verifier.getClassName()).getConstantPool());
final InstOperandConstraintVisitor v = new InstOperandConstraintVisitor(cpg);
// Checks for the things BCEL does _not_ handle itself.
InstructionHandle ih = instructionList.getStart();
while (ih != null) {
final Instruction i = ih.getInstruction();
// An "own" constraint, due to JustIce's new definition of what "subroutine" means.
if (i instanceof JsrInstruction) {
final InstructionHandle target = ((JsrInstruction) i).getTarget();
if (target == instructionList.getStart()) {
throw new StaticCodeInstructionOperandConstraintException(
"Due to JustIce's clear definition of subroutines, no JSR or JSR_W may have a top-level instruction"
+ " (such as the very first instruction, which is targeted by instruction '" + tostring(ih) + "' as its target.");
}
if (!(target.getInstruction() instanceof ASTORE)) {
throw new StaticCodeInstructionOperandConstraintException(
"Due to JustIce's clear definition of subroutines, no JSR or JSR_W may target anything else"
+ " than an ASTORE instruction. Instruction '" + tostring(ih) + "' targets '" + tostring(target) + "'.");
}
}
// vmspec2, page 134-137
ih.accept(v);
ih = ih.getNext();
}
} catch (final ClassNotFoundException e) {
// FIXME: maybe not the best way to handle this
throw new AssertionViolatedException("Missing class: " + e, e);
}
}
/**
* This method is a slightly modified version of verifier.statics.StringRepresentation.toString(final Node obj) that
* accepts any Object, not just a Node.
*
* Returns the String representation of the Object obj; this is obj.toString() if it does not throw any
* RuntimeException, or else it is a string derived only from obj's class name.
*/
protected String tostring(final Object obj) {
String ret;
try {
ret = obj.toString();
}
catch (final RuntimeException e) {
// including ClassFormatException, trying to convert the "signature" of a ReturnaddressType LocalVariable
// (shouldn't occur, but people do crazy things)
String s = obj.getClass().getName();
s = s.substring(s.lastIndexOf(".") + 1);
ret = "<<" + s + ">>";
}
return ret;
}
}