BCEL-341: Oak class file patch

src/main/java/org/apache/bcel/classfile/Attribute.java

@@ -133,6 +133,13 @@ protected static void println(final String msg) {
      * @since 6.0
      */
     public static Attribute readAttribute(final DataInput dataInput, final ConstantPool constantPool) throws IOException {
+        return readAttribute(dataInput, constantPool, false);
+    }
+
+    /**
+     * Reads an attribute using the Code encoding selected by the enclosing class file's version.
+     */
+    static Attribute readAttribute(final DataInput dataInput, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
         // Track the nesting depth to guard against malicious class files that nest attributes (for example, a Code attribute inside a Code attribute, or
         // mutually recursive Record component attributes) deeply enough to overflow the parser's stack (CWE-674).
         final int depth = NESTING_DEPTH.get().intValue() + 1;
@@ -143,7 +150,7 @@ public static Attribute readAttribute(final DataInput dataInput, final ConstantP
         }
         NESTING_DEPTH.set(Integer.valueOf(depth));
         try {
-            return readAttribute0(dataInput, constantPool);
+            return readAttribute0(dataInput, constantPool, legacyCodeFormat);
         } finally {
             if (depth == 1) {
                 NESTING_DEPTH.remove();
@@ -169,9 +176,9 @@ public static Attribute readAttribute(final DataInputStream dataInputStream, fin
     }
 
     /**
-     * Reads one attribute without tracking the nesting depth; only to be called by {@link #readAttribute(DataInput, ConstantPool)}.
+     * Reads one attribute without tracking the nesting depth; only to be called by {@link #readAttribute(DataInput, ConstantPool, boolean)}.
      */
-    private static Attribute readAttribute0(final DataInput dataInput, final ConstantPool constantPool) throws IOException {
+    private static Attribute readAttribute0(final DataInput dataInput, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
         byte tag = Const.ATTR_UNKNOWN; // Unknown attribute
         // Get class name from constant pool via 'name_index' indirection
         final int nameIndex = dataInput.readUnsignedShort();
@@ -201,7 +208,7 @@ private static Attribute readAttribute0(final DataInput dataInput, final Constan
         case Const.ATTR_SOURCE_FILE:
             return new SourceFile(nameIndex, length, dataInput, constantPool);
         case Const.ATTR_CODE:
-            return new Code(nameIndex, length, dataInput, constantPool);
+            return new Code(nameIndex, length, dataInput, constantPool, legacyCodeFormat);
         case Const.ATTR_EXCEPTIONS:
             return new ExceptionTable(nameIndex, length, dataInput, constantPool);
         case Const.ATTR_LINE_NUMBER_TABLE:
@@ -256,7 +263,7 @@ private static Attribute readAttribute0(final DataInput dataInput, final Constan
         case Const.ATTR_NEST_MEMBERS:
             return new NestMembers(nameIndex, length, dataInput, constantPool);
         case Const.ATTR_RECORD:
-            return new Record(nameIndex, length, dataInput, constantPool);
+            return new Record(nameIndex, length, dataInput, constantPool, legacyCodeFormat);
         case Const.ATTR_PERMITTED_SUBCLASSES:
             return new PermittedSubclasses(nameIndex, length, dataInput, constantPool);
         case Const.ATTR_RUNTIME_VISIBLE_TYPE_ANNOTATIONS:

src/main/java/org/apache/bcel/classfile/ClassParser.java

@@ -60,6 +60,7 @@ static int[] readU2U2Table(final DataInput dataInput) throws IOException {
     private int superclassNameIndex;
     private int major; // Compiler version
     private int minor; // Compiler version
+    private boolean legacyCodeFormat; // True if class file version is <=45.2
     private int accessFlags; // Access rights of parsed class
     private int[] interfaces; // Names of implemented interfaces
     private ConstantPool constantPool; // collection of constants
@@ -192,7 +193,7 @@ private void readAttributes() throws IOException, ClassFormatException {
         final int attributesCount = dataInputStream.readUnsignedShort();
         attributes = new Attribute[attributesCount];
         for (int i = 0; i < attributesCount; i++) {
-            attributes[i] = Attribute.readAttribute(dataInputStream, constantPool);
+            attributes[i] = Attribute.readAttribute(dataInputStream, constantPool, legacyCodeFormat);
         }
     }
 
@@ -237,7 +238,7 @@ private void readFields() throws IOException, ClassFormatException {
         final int fieldsCount = dataInputStream.readUnsignedShort();
         fields = new Field[fieldsCount];
         for (int i = 0; i < fieldsCount; i++) {
-            fields[i] = new Field(dataInputStream, constantPool);
+            fields[i] = new Field(dataInputStream, constantPool, legacyCodeFormat);
         }
     }
 
@@ -273,7 +274,7 @@ private void readMethods() throws IOException {
         final int methodsCount = dataInputStream.readUnsignedShort();
         methods = new Method[methodsCount];
         for (int i = 0; i < methodsCount; i++) {
-            methods[i] = new Method(dataInputStream, constantPool);
+            methods[i] = new Method(dataInputStream, constantPool, legacyCodeFormat);
         }
     }
 
@@ -286,5 +287,6 @@ private void readMethods() throws IOException {
     private void readVersion() throws IOException, ClassFormatException {
         minor = dataInputStream.readUnsignedShort();
         major = dataInputStream.readUnsignedShort();
+        legacyCodeFormat = major < Const.MAJOR_1_1 || major == Const.MAJOR_1_1 && minor < Const.MINOR_1_1;
     }
 }

src/main/java/org/apache/bcel/classfile/Code.java

@@ -63,6 +63,10 @@
  */
 public final class Code extends Attribute {
 
+    /**
+     * Whether the Code header uses the smaller fields of class file versions up to 45.2.
+     */
+    private final boolean legacyCodeFormat;
     private int maxStack; // Maximum size of stack used by this method // TODO this could be made final (setter is not used)
     private int maxLocals; // Number of local variables // TODO this could be made final (setter is not used)
     private byte[] code; // Actual byte code
@@ -77,7 +81,7 @@ public final class Code extends Attribute {
      */
     public Code(final Code code) {
         this(code.getNameIndex(), code.getLength(), code.getMaxStack(), code.getMaxLocals(), code.getCode(), code.getExceptionTable(), code.getAttributes(),
-                code.getConstantPool());
+                code.getConstantPool(), code.legacyCodeFormat);
     }
 
     /**
@@ -90,10 +94,18 @@ public Code(final Code code) {
      * @throws ClassFormatException Thrown if the code array read from {@code file} is greater than {@link Const#MAX_CODE_SIZE}.
      */
     Code(final int nameIndex, final int length, final DataInput dataInput, final ConstantPool constantPool) throws IOException {
+        this(nameIndex, length, dataInput, constantPool, false);
+    }
+
+    /**
+     * Reads a Code attribute using the header widths selected by the enclosing class file's version.
+     */
+    Code(final int nameIndex, final int length, final DataInput dataInput, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
         // Initialize with some default values which will be overwritten later
-        this(nameIndex, length, dataInput.readUnsignedShort(), dataInput.readUnsignedShort(), (byte[]) null, (CodeException[]) null, (Attribute[]) null,
-                constantPool);
-        final int codeLength = Args.requireU4(dataInput.readInt(), 0, Const.MAX_CODE_SIZE, "Code length attribute");
+        this(nameIndex, length, legacyCodeFormat ? dataInput.readUnsignedByte() : dataInput.readUnsignedShort(),
+                legacyCodeFormat ? dataInput.readUnsignedByte() : dataInput.readUnsignedShort(), null, null, null, constantPool, legacyCodeFormat);
+        final int codeLength = Args.requireU4(legacyCodeFormat ? dataInput.readUnsignedShort() : dataInput.readInt(), 0, Const.MAX_CODE_SIZE,
+                "Code length attribute");
         code = new byte[codeLength]; // Read byte code
         dataInput.readFully(code);
         /*
@@ -110,7 +122,7 @@ public Code(final Code code) {
         final int attributesCount = dataInput.readUnsignedShort();
         attributes = new Attribute[attributesCount];
         for (int i = 0; i < attributesCount; i++) {
-            attributes[i] = readAttribute(dataInput, constantPool);
+            attributes[i] = readAttribute(dataInput, constantPool, legacyCodeFormat);
         }
         /*
          * Adjust length, because of setAttributes in this(), s.b. length is incorrect, because it didn't take the internal attributes into account yet! Very
@@ -134,7 +146,13 @@ public Code(final Code code) {
      */
     public Code(final int nameIndex, final int length, final int maxStack, final int maxLocals, final byte[] code, final CodeException[] exceptionTable,
         final Attribute[] attributes, final ConstantPool constantPool) {
+        this(nameIndex, length, maxStack, maxLocals, code, exceptionTable, attributes, constantPool, false);
+    }
+
+    private Code(final int nameIndex, final int length, final int maxStack, final int maxLocals, final byte[] code, final CodeException[] exceptionTable,
+        final Attribute[] attributes, final ConstantPool constantPool, final boolean legacyCodeFormat) {
         super(Const.ATTR_CODE, nameIndex, length, constantPool);
+        this.legacyCodeFormat = legacyCodeFormat;
         this.maxStack = Args.requireU2(maxStack, "maxStack");
         this.maxLocals = Args.requireU2(maxLocals, "maxLocals");
         this.code = ArrayUtils.nullToEmpty(code);
@@ -197,10 +215,21 @@ public Attribute copy(final ConstantPool constantPool) {
      */
     @Override
     public void dump(final DataOutputStream file) throws IOException {
+        if (legacyCodeFormat) {
+            Args.requireU1(maxStack, "maxStack");
+            Args.requireU1(maxLocals, "maxLocals");
+            Args.requireU2(code.length, "Code length attribute");
+        }
         super.dump(file);
-        file.writeShort(maxStack);
-        file.writeShort(maxLocals);
-        file.writeInt(code.length);
+        if (legacyCodeFormat) {
+            file.writeByte(maxStack);
+            file.writeByte(maxLocals);
+            file.writeShort(code.length);
+        } else {
+            file.writeShort(maxStack);
+            file.writeShort(maxLocals);
+            file.writeInt(code.length);
+        }
         file.write(code, 0, code.length);
         file.writeShort(Args.requireU2(exceptionTable.length, "exceptionTable.length"));
         for (final CodeException exception : exceptionTable) {
@@ -247,7 +276,7 @@ public CodeException[] getExceptionTable() {
      * @return The internal length of this code attribute (minus the first 6 bytes) and excluding all its attributes.
      */
     private int getInternalLength() {
-        return 2 /* maxStack */ + 2 /* maxLocals */ + 4 /* code length */
+        return (legacyCodeFormat ? 4 : 8) /* maxStack, maxLocals, code length */
             + code.length /* byte-code */
             + 2 /* exception-table length */
             + 8 * (exceptionTable == null ? 0 : exceptionTable.length) /* exception table */

src/main/java/org/apache/bcel/classfile/Field.java

@@ -77,7 +77,11 @@ public static void setComparator(final BCELComparator<Field> comparator) {
      * @param constantPool The constant pool.
      */
     Field(final DataInput file, final ConstantPool constantPool) throws IOException, ClassFormatException {
-        super(file, constantPool);
+        this(file, constantPool, false);
+    }
+
+    Field(final DataInput file, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
+        super(file, constantPool, legacyCodeFormat);
     }
 
     /**

src/main/java/org/apache/bcel/classfile/FieldOrMethod.java

@@ -78,11 +78,15 @@ public abstract class FieldOrMethod extends AccessFlags implements Cloneable, No
      * @throws IOException Thrown if an I/O error occurs.
      */
     protected FieldOrMethod(final DataInput file, final ConstantPool constantPool) throws IOException {
+        this(file, constantPool, false);
+    }
+
+    FieldOrMethod(final DataInput file, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
         this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), null, constantPool);
         final int attributesCount = file.readUnsignedShort();
         attributes = new Attribute[attributesCount];
         for (int i = 0; i < attributesCount; i++) {
-            attributes[i] = Attribute.readAttribute(file, constantPool);
+            attributes[i] = Attribute.readAttribute(file, constantPool, legacyCodeFormat);
         }
         this.attributes_count = attributesCount; // init deprecated field
     }

src/main/java/org/apache/bcel/classfile/Method.java

@@ -86,7 +86,11 @@ public Method() {
      * @throws ClassFormatException Thrown if a class is malformed or cannot be interpreted as a class file.
      */
     Method(final DataInput file, final ConstantPool constantPool) throws IOException, ClassFormatException {
-        super(file, constantPool);
+        this(file, constantPool, false);
+    }
+
+    Method(final DataInput file, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
+        super(file, constantPool, legacyCodeFormat);
     }
 
     /**

src/main/java/org/apache/bcel/classfile/Record.java

@@ -39,12 +39,12 @@ public final class Record extends Attribute {
 
     private static final RecordComponentInfo[] EMPTY_RCI_ARRAY = {};
 
-    private static RecordComponentInfo[] readComponents(final DataInput input, final ConstantPool constantPool)
+    private static RecordComponentInfo[] readComponents(final DataInput input, final ConstantPool constantPool, final boolean legacyCodeFormat)
             throws IOException {
         final int classCount = input.readUnsignedShort();
         final RecordComponentInfo[] components = new RecordComponentInfo[classCount];
         for (int i = 0; i < classCount; i++) {
-            components[i] = new RecordComponentInfo(input, constantPool);
+            components[i] = new RecordComponentInfo(input, constantPool, legacyCodeFormat);
         }
         return components;
     }
@@ -62,7 +62,12 @@ private static RecordComponentInfo[] readComponents(final DataInput input, final
      */
     Record(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool)
             throws IOException {
-        this(nameIndex, length, readComponents(input, constantPool), constantPool);
+        this(nameIndex, length, input, constantPool, false);
+    }
+
+    Record(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool, final boolean legacyCodeFormat)
+            throws IOException {
+        this(nameIndex, length, readComponents(input, constantPool, legacyCodeFormat), constantPool);
     }
 
     /**

src/main/java/org/apache/bcel/classfile/RecordComponentInfo.java

@@ -48,12 +48,16 @@ public class RecordComponentInfo implements Node {
      * @throws IOException Thrown if an I/O error occurs.
      */
     public RecordComponentInfo(final DataInput input, final ConstantPool constantPool) throws IOException {
+        this(input, constantPool, false);
+    }
+
+    RecordComponentInfo(final DataInput input, final ConstantPool constantPool, final boolean legacyCodeFormat) throws IOException {
         this.index = input.readUnsignedShort();
         this.descriptorIndex = input.readUnsignedShort();
         final int attributesCount = input.readUnsignedShort();
         this.attributes = new Attribute[attributesCount];
         for (int j = 0; j < attributesCount; j++) {
-            attributes[j] = Attribute.readAttribute(input, constantPool);
+            attributes[j] = Attribute.readAttribute(input, constantPool, legacyCodeFormat);
         }
         this.constantPool = constantPool;
     }

src/test/java/org/apache/bcel/classfile/ClassParserTest.java

@@ -19,8 +19,11 @@
 
 package org.apache.bcel.classfile;
 
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.io.IOException;
+
 import org.junit.jupiter.api.Test;
 
 /**
@@ -32,4 +35,9 @@ class ClassParserTest {
     void testParseInvalidClass() {
         assertThrows(ClassFormatException.class, () -> new ClassParser("src/test/resources/org/apache/commons/bcel/classfile/CodeCtor.class").parse());
     }
+
+    @Test
+    void testParseOakClassFile() throws IOException {
+        assertNotNull(new ClassParser("src/test/resources/Java1OakExample.class").parse());
+    }
 }

src/test/resources/Java1OakExample.java

@@ -0,0 +1,5 @@
+public class Java1OakExample {
+    public static void main(String args[]) {
+        System.out.println("Hello Oak!");
+    }
+}