8336032: Enforce immutability of Lists used by ClassFile API

Reviewed-by: asotona

src/java.base/share/classes/java/lang/classfile/AttributedElement.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,7 @@
 package java.lang.classfile;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
@@ -83,6 +84,6 @@ public sealed interface AttributedElement extends ClassFileElement
                 list.add(t);
             }
         }
-        return list;
+        return Collections.unmodifiableList(list);
     }
 }

src/java.base/share/classes/java/lang/classfile/ClassSignature.java

@@ -76,7 +76,7 @@ public sealed interface ClassSignature
                                     Signature.ClassTypeSig superclassSignature,
                                     Signature.ClassTypeSig... superinterfaceSignatures) {
         return new SignaturesImpl.ClassSignatureImpl(
-                requireNonNull(typeParameters),
+                List.copyOf(requireNonNull(typeParameters)),
                 requireNonNull(superclassSignature),
                 List.of(superinterfaceSignatures));
     }

src/java.base/share/classes/java/lang/classfile/CompoundElement.java

@@ -25,6 +25,7 @@
 package java.lang.classfile;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Spliterator;
@@ -90,7 +91,7 @@ public sealed interface CompoundElement<E extends ClassFileElement>
                 list.add(e);
             }
         });
-        return list;
+        return Collections.unmodifiableList(list);
     }
 
 }

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractUnboundModel.java

@@ -24,6 +24,7 @@
  */
 package jdk.internal.classfile.impl;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
@@ -37,11 +38,11 @@ public abstract sealed class AbstractUnboundModel<E extends ClassFileElement>
         extends AbstractElement
         implements CompoundElement<E>, AttributedElement
         permits BufferedCodeBuilder.Model, BufferedFieldBuilder.Model, BufferedMethodBuilder.Model {
-    private final List<E> elements;
+    final List<E> elements;
     private List<Attribute<?>> attributes;
 
     public AbstractUnboundModel(List<E> elements) {
-        this.elements = elements;
+        this.elements = Collections.unmodifiableList(elements);
     }
 
     @Override

src/java.base/share/classes/jdk/internal/classfile/impl/BoundAttribute.java

@@ -39,6 +39,7 @@ import java.lang.classfile.constantpool.Utf8Entry;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
 
@@ -134,7 +135,6 @@ public abstract sealed class BoundAttribute<T extends Attribute<T>>
         var filled = new ArrayList<Attribute<?>>(size);
         int p = pos + 2;
         int cfLen = reader.classfileLength();
-        var apo = ((ClassReaderImpl)reader).context().attributesProcessingOption();
         for (int i = 0; i < size; ++i) {
             Utf8Entry name = reader.readEntry(p, Utf8Entry.class);
             int len = reader.readInt(p + 2);
@@ -148,7 +148,7 @@ public abstract sealed class BoundAttribute<T extends Attribute<T>>
                 mapper = customAttributes.apply(name);
             }
             if (mapper != null) {
-                filled.add((Attribute)mapper.readAttribute(enclosing, reader, p));
+                filled.add((Attribute<?>) Objects.requireNonNull(mapper.readAttribute(enclosing, reader, p)));
             } else {
                 AttributeMapper<UnknownAttribute> fakeMapper = new AttributeMapper<>() {
                     @Override

src/java.base/share/classes/jdk/internal/classfile/impl/BufferedCodeBuilder.java

@@ -148,7 +148,7 @@ public final class BufferedCodeBuilder
             implements CodeModel {
 
         private Model() {
-            super(elements);
+            super(BufferedCodeBuilder.this.elements);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/classfile/impl/BufferedFieldBuilder.java

@@ -78,7 +78,7 @@ public final class BufferedFieldBuilder
             extends AbstractUnboundModel<FieldElement>
             implements FieldModel {
         public Model() {
-            super(elements);
+            super(BufferedFieldBuilder.this.elements);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/classfile/impl/BufferedMethodBuilder.java

@@ -156,7 +156,7 @@ public final class BufferedMethodBuilder
             extends AbstractUnboundModel<MethodElement>
             implements MethodModel, MethodInfo {
         public Model() {
-            super(elements);
+            super(BufferedMethodBuilder.this.elements);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/classfile/impl/StackMapDecoder.java

@@ -285,5 +285,9 @@ public class StackMapDecoder {
                                            List<VerificationTypeInfo> locals,
                                            List<VerificationTypeInfo> stack)
             implements StackMapFrameInfo {
+        public StackMapFrameImpl {
+            locals = List.copyOf(locals);
+            stack = List.copyOf(stack);
+        }
     }
 }

src/java.base/share/classes/jdk/internal/classfile/impl/UnboundAttribute.java

@@ -92,6 +92,8 @@ import java.lang.classfile.constantpool.NameAndTypeEntry;
 import java.lang.classfile.constantpool.PackageEntry;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import jdk.internal.access.SharedSecrets;
+
 public abstract sealed class UnboundAttribute<T extends Attribute<T>>
         extends AbstractElement
         implements Attribute<T>, Util.Writable {
@@ -627,7 +629,13 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundRuntimeInvisibleParameterAnnotationsAttribute(List<List<Annotation>> elements) {
             super(Attributes.runtimeInvisibleParameterAnnotations());
-            this.elements = List.copyOf(elements);
+            // deep copy
+            var array = elements.toArray().clone();
+            for (int i = 0; i < array.length; i++) {
+                array[i] = List.copyOf((List<?>) array[i]);
+            }
+
+            this.elements = SharedSecrets.getJavaUtilCollectionAccess().listFromTrustedArray(array);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/classfile/impl/verifier/VerifierImpl.java

@@ -26,6 +26,7 @@ package jdk.internal.classfile.impl.verifier;
 
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.function.Consumer;
 import java.lang.classfile.ClassHierarchyResolver;
@@ -133,7 +134,7 @@ public final class VerifierImpl {
                     errors.addAll(inference_verify(klass));
                 }
             }
-            return errors;
+            return Collections.unmodifiableList(errors);
         } finally {
             log_info(logger, "End class verification for: %s", clsName);
         }