java-topology/test/jdk/java/lang/ClassLoader/defineClass/DefineClassDirectByteBuffer.java
russell@unturf.com 0a580b313d undefect. CWE-407 — 63 sites patched across 27 ecosystems
Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.
2026-03-26 17:11:57 -04:00

297 lines
13 KiB
Java

/*
* Copyright (c) 2025, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @summary Test various cases of passing java.nio.ByteBuffers to defineClass().
* @bug 8365588
*
* @build DefineClassDirectByteBuffer
* @run junit/othervm --add-opens java.base/java.lang=ALL-UNNAMED -Dmode=Direct DefineClassDirectByteBuffer
* @run junit/othervm --add-opens java.base/java.lang=ALL-UNNAMED -Dmode=Heap DefineClassDirectByteBuffer
*/
import java.lang.foreign.Arena;
import java.lang.reflect.Method;
import java.nio.*;
import java.nio.channels.*;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.security.ProtectionDomain;
import java.util.HexFormat;
import java.util.stream.Stream;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import static org.junit.Assert.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
public class DefineClassDirectByteBuffer {
// this is for the trusted/biltin classloader
private static final String mode = System.getProperty("mode", "Direct");
private static final int CLASSBYTES_OFFSET = 16;
// -------- untrusted path (custom loader) --------
static Stream<ByteBuffer> bytebuffers() throws Exception {
byte[] classBytes = getTestClassBytes();
byte[] classBytesAtOffset = new byte[classBytes.length + CLASSBYTES_OFFSET];
System.arraycopy(classBytes, 0, classBytesAtOffset, CLASSBYTES_OFFSET, classBytes.length);
return Stream.of(
// WRAPPED_BUFFER
ByteBuffer.wrap(classBytes),
ByteBuffer.wrap(classBytes)
.asReadOnlyBuffer(),
ByteBuffer.wrap(classBytesAtOffset)
.position(CLASSBYTES_OFFSET),
ByteBuffer.wrap(classBytesAtOffset)
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// ARRAY_BUFFER
ByteBuffer.allocate(classBytes.length)
.put(classBytes)
.flip(),
ByteBuffer.allocate(classBytes.length)
.put(classBytes)
.flip()
.asReadOnlyBuffer(),
ByteBuffer.allocate(classBytesAtOffset.length)
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET),
ByteBuffer.allocate(classBytesAtOffset.length)
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// DIRECT_BUFFER
ByteBuffer.allocateDirect(classBytes.length)
.put(classBytes)
.flip(),
ByteBuffer.allocateDirect(classBytes.length)
.put(classBytes)
.flip()
.asReadOnlyBuffer(),
ByteBuffer.allocateDirect(classBytesAtOffset.length)
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET),
ByteBuffer.allocateDirect(classBytesAtOffset.length)
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// FOREIGN_AUTO_BUFFER
Arena.ofAuto()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip(),
Arena.ofAuto()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip()
.asReadOnlyBuffer(),
Arena.ofAuto()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET),
Arena.ofAuto()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// FOREIGN_CONFINED_BUFFER
Arena.ofConfined()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip(),
Arena.ofConfined()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip()
.asReadOnlyBuffer(),
Arena.ofConfined()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET),
Arena.ofConfined()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// FOREIGN_GLOBAL_BUFFER
Arena.global()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip(),
Arena.global()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip()
.asReadOnlyBuffer(),
Arena.global()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET),
Arena.global()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// FOREIGN_SHARED_BUFFER
Arena.ofShared()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip(),
Arena.ofShared()
.allocate(classBytes.length)
.asByteBuffer()
.put(classBytes)
.flip()
.asReadOnlyBuffer(),
Arena.ofShared()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET),
Arena.ofShared()
.allocate(classBytesAtOffset.length)
.asByteBuffer()
.put(classBytesAtOffset)
.flip()
.position(CLASSBYTES_OFFSET)
.asReadOnlyBuffer(),
// MAPPED_BUFFER: MapMode.READ_ONLY from READ fc, the bb is readonly
getMappedByteBuffer(classBytes, 0),
getMappedByteBuffer(classBytesAtOffset, CLASSBYTES_OFFSET)
);
}
static ByteBuffer getMappedByteBuffer(byte[] classBytes, int offset) throws Exception {
Path tempDir = Paths.get(System.getProperty("test.classes", "."));
Files.createDirectories(tempDir);
Path tempClassFile = tempDir.resolve(
String.format("DefineClassDirectByteBuffer_Greeting_%d.class", offset));
Files.write(tempClassFile, classBytes);
try (FileChannel fc = FileChannel.open(tempClassFile, StandardOpenOption.READ)) {
return fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size()).position(offset);
}
}
@ParameterizedTest()
@MethodSource("bytebuffers")
void testDefineClassWithCustomLoaderByteBuffer(ByteBuffer bb) throws Exception {
int originalPos = bb.position();
int originalLimit = bb.limit();
CustomClassLoader loader = new CustomClassLoader();
Class<?> clazz = loader.defineClassFromByteBuffer(bb);
assertInvocating(clazz);
// long-standing (and undocumented) behavior, see JDK-8352583
if (bb.isDirect() || bb.hasArray()) {
assertEquals(originalPos, bb.position());
} else {
assertEquals(originalLimit, bb.position());
}
}
// -------- trusted path (BuiltinClassLoader) --------
@Test
void testDefineClassWithBuiltinLoaderByteBuffer() throws Exception {
var classBytes = getTestClassBytes();
var builtin = ClassLoader.getPlatformClassLoader();
var bb = mode.equals("Direct")
? ByteBuffer.allocateDirect(classBytes.length).put(classBytes).flip()
: ByteBuffer.allocate(classBytes.length).put(classBytes).flip();
var originalPos = bb.position();
// reflectively call protected defineClass(String, ByteBuffer, ProtectionDomain)
Method m = ClassLoader.class.getDeclaredMethod(
"defineClass", String.class, ByteBuffer.class, ProtectionDomain.class
);
m.setAccessible(true);
Class<?> clazz = (Class<?>) m.invoke(builtin, null, bb, null);
assertInvocating(clazz);
assertEquals(originalPos, bb.position());
}
// -------- shared helpers --------
private static void assertInvocating(Class<?> clazz) throws Exception {
var instance = clazz.getDeclaredConstructor().newInstance();
var m = clazz.getMethod("hello");
assertEquals("Hello", m.invoke(instance));
}
private static class CustomClassLoader extends ClassLoader {
Class<?> defineClassFromByteBuffer(ByteBuffer bb) throws Exception {
return defineClass(null, bb, null);
}
}
private static byte[] getTestClassBytes() throws Exception {
final String source = """
public class Greeting {
public String hello() {
return "Hello";
}
}
""";
// (externally) compiled content of the above source, represented as hex
final String classBytesHex = """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""";
return HexFormat.of().parseHex(classBytesHex.replaceAll("\n", ""));
}
}