Merge pull request #4876 from gacholio/ann

Use a class annotation to prevent instrumentation

debugtools/DDR_VM/src/com/ibm/j9ddr/vm29/tools/ddrinteractive/commands/J9BCUtil.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2001, 2018 IBM Corp. and others
+ * Copyright (c) 2001, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -556,7 +556,7 @@ public static void j9bcutil_dumpRomClass(PrintStream out, J9ROMClassPointer romC
 
 		out.append(String.format("Sun Access Flags (0x%s): ", Long.toHexString(romClass.modifiers().longValue())));
 		dumpModifiers(out, romClass.modifiers().longValue(), MODIFIERSOURCE_CLASS, ONLY_SPEC_MODIFIERS);
-
+		out.append(nl);
 		out.append(String.format("J9  Access Flags (0x%s): ", Long.toHexString(romClass.extraModifiers().longValue())));
 		dumpClassJ9ExtraModifiers(out, romClass.extraModifiers().longValue());
 		out.append(nl);
@@ -708,6 +708,8 @@ private static void dumpClassJ9ExtraModifiers(PrintStream out, long accessFlags)
 			out.append("(preverified) ");
 		if ((accessFlags & J9JavaAccessFlags.J9AccClassAnonClass) != 0)
 			out.append("(anonClass) ");
+		if ((accessFlags & J9JavaAccessFlags.J9AccClassIsUnmodifiable) != 0)
+			out.append("(unmodifiable) ");
 	}
 
 	private static void dumpEnclosingMethod(PrintStream out, J9ROMClassPointer romClass, long flags) throws CorruptDataException {

jcl/src/java.base/share/classes/com/ibm/jit/JITHelpers.java

@@ -3,7 +3,7 @@
 package com.ibm.jit;
 
 /*******************************************************************************
- * Copyright (c) 1998, 2018 IBM Corp. and others
+ * Copyright (c) 1998, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -24,6 +24,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
  *******************************************************************************/
 
+import com.ibm.oti.vm.J9UnmodifiableClass;
 import java.lang.reflect.Field;
 import java.lang.reflect.Array;
 import com.ibm.oti.vm.VM;
@@ -41,6 +42,7 @@
  * The <code>JITHelpers</code> class contains methods used by the JIT to optimize certain primitive operations.
  */
 @SuppressWarnings("javadoc")
+@J9UnmodifiableClass
 public final class JITHelpers {
 
 	private static final JITHelpers helpers;

jcl/src/java.base/share/classes/com/ibm/oti/vm/J9UnmodifiableClass.java

@@ -0,0 +1,41 @@
+/*[INCLUDE-IF Sidecar17]*/
+/*******************************************************************************
+ * Copyright (c) 2019, 2019 IBM Corp. and others
+ *
+ * This program and the accompanying materials are made available under
+ * the terms of the Eclipse Public License 2.0 which accompanies this
+ * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
+ * or the Apache License, Version 2.0 which accompanies this distribution and
+ * is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * This Source Code may also be made available under the following
+ * Secondary Licenses when the conditions for such availability set
+ * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
+ * General Public License, version 2 with the GNU Classpath
+ * Exception [1] and GNU General Public License, version 2 with the
+ * OpenJDK Assembly Exception [2].
+ *
+ * [1] https://www.gnu.org/software/classpath/license.html
+ * [2] http://openjdk.java.net/legal/assembly-exception.html
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
+ *******************************************************************************/
+
+package com.ibm.oti.vm;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.TYPE})
+
+// WARNING: Do not rename or repackage this class without changing
+// J9_UNMODIFIABLE_CLASS_ANNOTATION in j9.h to match. Under no
+// circumstances include any character whose ASCII value is
+// less than that of '/' (see canClassBeInstrumented in jvmtiHook.c).
+
+public @interface J9UnmodifiableClass {
+}
+

jcl/src/java.base/share/classes/java/lang/J9VMInternals.java

@@ -2,6 +2,7 @@
 
 package java.lang;
 
+import com.ibm.oti.vm.J9UnmodifiableClass;
 import java.lang.ref.SoftReference;
 import java.lang.reflect.*;
 import java.security.AccessController;
@@ -30,7 +31,7 @@
 
 
 /*******************************************************************************
- * Copyright (c) 1998, 2018 IBM Corp. and others
+ * Copyright (c) 1998, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -51,6 +52,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
  *******************************************************************************/
 
+@J9UnmodifiableClass
 final class J9VMInternals {
 	/*[PR VMDESIGN 1891] Move j9Version and j9Config from Class to J9VMInternals */
 	/*[IF]*/

jcl/src/java.base/share/classes/java/lang/invoke/VarHandleInternal.java

@@ -1,6 +1,6 @@
 /*[INCLUDE-IF Sidecar19-SE]*/
 /*******************************************************************************
- * Copyright (c) 2017, 2017 IBM Corp. and others
+ * Copyright (c) 2017, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -22,6 +22,9 @@
  *******************************************************************************/
 package java.lang.invoke;
 
+import com.ibm.oti.vm.J9UnmodifiableClass;
+
+@J9UnmodifiableClass
 class VarHandleInternal {
 	/*[IF ]*/
 	/* Methods with VarHandle send target 

runtime/bcutil/ClassFileOracle.cpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2001, 2018 IBM Corp. and others
+ * Copyright (c) 2001, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -56,6 +56,7 @@ ClassFileOracle::KnownAnnotation ClassFileOracle::_knownAnnotations[] = {
 #define CONTENDED_SIGNATURE "Ljdk/internal/vm/annotation/Contended;"
 		{CONTENDED_SIGNATURE, sizeof(CONTENDED_SIGNATURE)},
 #undef CONTENDED_SIGNATURE
+		{J9_UNMODIFIABLE_CLASS_ANNOTATION, sizeof(J9_UNMODIFIABLE_CLASS_ANNOTATION)},
 		{0, 0}
 };
 
@@ -180,6 +181,7 @@ ClassFileOracle::ClassFileOracle(BufferManager *bufferManager, J9CfrClassFile *c
 	_nestMembers(NULL),
 #endif /* J9VM_OPT_VALHALLA_NESTMATES */
 	_isClassContended(false),
+	_isClassUnmodifiable(context->isClassUnmodifiable()),
 	_isInnerClass(false)
 {
 	Trc_BCU_Assert_NotEquals( classFile, NULL );
@@ -447,12 +449,16 @@ ClassFileOracle::walkAttributes()
 				knownAnnotations = addAnnotationBit(knownAnnotations, CONTENDED_ANNOTATION);
 				knownAnnotations = addAnnotationBit(knownAnnotations, JAVA8_CONTENDED_ANNOTATION);
 			}
+			knownAnnotations = addAnnotationBit(knownAnnotations, UNMODIFIABLE_ANNOTATION);
 			_annotationsAttribute = (J9CfrAttributeRuntimeVisibleAnnotations *)attrib;
 			if (0 == _annotationsAttribute->rawDataLength) {
 				UDATA foundAnnotations = walkAnnotations(_annotationsAttribute->numberOfAnnotations, _annotationsAttribute->annotations, knownAnnotations);
 				if (containsKnownAnnotation(foundAnnotations, CONTENDED_ANNOTATION) || containsKnownAnnotation(foundAnnotations, JAVA8_CONTENDED_ANNOTATION)) {
 					_isClassContended = true;
 				}
+				if (containsKnownAnnotation(foundAnnotations, UNMODIFIABLE_ANNOTATION)) {
+					_isClassUnmodifiable = true;
+				}
 			}
 			break;
 		}

runtime/bcutil/ClassFileOracle.hpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2001, 2018 IBM Corp. and others
+ * Copyright (c) 2001, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -907,6 +907,7 @@ class NameAndTypeIterator
 	bool hasEmptyFinalizeMethod() const { return _hasEmptyFinalizeMethod; }
 	bool hasFinalFields() const { return _hasFinalFields; }
 	bool isClassContended() const { return _isClassContended; }
+	bool isClassUnmodifiable() const { return _isClassUnmodifiable; }
 	bool hasNonStaticNonAbstractMethods() const { return _hasNonStaticNonAbstractMethods; }
 	bool hasFinalizeMethod() const { return _hasFinalizeMethod; }
 	bool isCloneable() const { return _isCloneable; }
@@ -949,6 +950,7 @@ class NameAndTypeIterator
 		JDK_INTERNAL_REFLECT_CALLERSENSITIVE_ANNOTATION,
 		JAVA8_CONTENDED_ANNOTATION,
 		CONTENDED_ANNOTATION,
+		UNMODIFIABLE_ANNOTATION,
 		KNOWN_ANNOTATION_COUNT
 	};
 
@@ -988,6 +990,7 @@ class NameAndTypeIterator
 	bool _isSerializable;
 	bool _isSynthetic;
 	bool _isClassContended;
+	bool _isClassUnmodifiable;
 	bool _hasVerifyExcludeAttribute;
 	bool _hasFrameIteratorSkipAnnotation;
 	bool _hasClinit;

runtime/bcutil/ROMClassBuilder.cpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2001, 2018 IBM Corp. and others
+ * Copyright (c) 2001, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -1064,7 +1064,7 @@ ROMClassBuilder::finishPrepareAndLaydown(
  *                             + UNUSED
  *                            + UNUSED
  *                           + UNUSED
- *                          + AccClassAnonClass;
+ *                          + AccClassAnonClass
  *
  *                        + AccSynthetic (matches Oracle modifier position)
  *                       + AccClassUseBisectionSearch
@@ -1078,10 +1078,10 @@ ROMClassBuilder::finishPrepareAndLaydown(
  *
  *              + AccClassBytecodesModified
  *             + AccClassHasEmptyFinalize
- *            + UNUSED
+ *            + AccClassIsUnmodifiable
  *           + AccClassHasVerifyData
  *
- *         + J9AccClassIsContended
+ *         + AccClassIsContended
  *        + AccClassHasFinalFields
  *       + AccClassHasClinit
  *      + AccClassHasNonStaticNonAbstractMethods
@@ -1127,6 +1127,10 @@ ROMClassBuilder::computeExtraModifiers(ClassFileOracle *classFileOracle, ROMClas
 		modifiers |= J9AccClassIsContended;
 	}
 
+	if ( classFileOracle->isClassUnmodifiable() ) {
+		modifiers |= J9AccClassIsUnmodifiable;
+	}
+
 	U_32 classNameindex = classFileOracle->getClassNameIndex();
 
 #define WEAK_NAME "java/lang/ref/WeakReference"

runtime/bcutil/ROMClassCreationContext.hpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2001, 2018 IBM Corp. and others
+ * Copyright (c) 2001, 2019 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -223,6 +223,21 @@ class ROMClassCreationContext
 	bool isClassAnon() const { return J9_FINDCLASS_FLAG_ANON == (_findClassFlags & J9_FINDCLASS_FLAG_ANON); }
 	bool alwaysSplitBytecodes() const { return J9_ARE_ANY_BITS_SET(_bctFlags, BCT_AlwaysSplitBytecodes); }
 
+	bool isClassUnmodifiable() const {
+		bool unmodifiable = false;
+		if (NULL != _javaVM) {
+			if ((J2SE_VERSION(_javaVM) >= J2SE_V11) && isClassAnon()) {
+				unmodifiable = true;
+			} else if (NULL == J9VMJAVALANGOBJECT_OR_NULL(_javaVM)) {
+				/* Object is currently only allowed to be redefined in fast HCR */
+				if (areExtensionsEnabled(_javaVM)) {
+					unmodifiable = true;
+				}
+			}
+		}
+		return unmodifiable;
+	}
+
 	bool isIntermediateClassDataShareable() const {
 		bool shareable = false;
 		U_8 *intermediateData = getIntermediateClassDataFromPreviousROMClass();

runtime/jvmti/jvmtiHook.c

@@ -2231,26 +2231,59 @@ jvmtiHookGCCycleEnd(J9HookInterface** hook, UDATA eventNum, void* eventData, voi
 }
 
 /**
- * Determines if the class described by <tt>classLoadData</tt> can 
+ * Determines if the class described by <tt>data</tt> can 
  * be instrumented.
- * @param classLoadData 
+ * @param data The class file load hook event data
  * @return TRUE if the class can be instrumented. 
  */
 static BOOLEAN
-canClassBeInstrumented(J9VMClassLoadHookEvent* classLoadData)
-{
-	BOOLEAN result = TRUE;
-
-	/* Skip any class that does not have a name specified */
-	if (classLoadData->className == NULL) {
-		result = FALSE;
-	} else if (strcmp(classLoadData->className, "java/lang/J9VMInternals") == 0) {
-		result = FALSE;
-	} else if (strcmp(classLoadData->className, "java/lang/invoke/VarHandleInternal") == 0) {
-		result = FALSE;
+canClassBeInstrumented(J9VMClassLoadHookEvent* data)
+{
+	BOOLEAN modifiable = TRUE;
+	/* Only clasess on the bootpath may be marked unmodifiable */
+	if (data->classLoader == data->currentThread->javaVM->systemClassLoader) {
+		U_8 *classData = data->classData;
+		UDATA const classDataLength = data->classDataLength;
+		UDATA const annotationLength = sizeof(J9_UNMODIFIABLE_CLASS_ANNOTATION_DATA);
+		/* Before the constant pool in the class file, there's at least:
+		 *
+		 *	u4 magic
+		 *	u2 minor_version
+		 *	u2 major_version
+		 *	u2 constant_pool_count
+		 *
+ 		 * Totalling 10 bytes.
+		 */
+		UDATA const minimumSize = 10;
+		if (classDataLength > (annotationLength + minimumSize)) {
+			/* Make sure this at least looks like a class file */
+			if ((0xCA == classData[0]) && (0xFE == classData[1]) && (0xBA == classData[2]) && (0xBE == classData[3])) {
+				U_8 *dataEnd = classData + classDataLength - annotationLength;
+				classData += minimumSize;
+				/* Search for the bytes representing the UTF8 annotation name */
+				while (classData < dataEnd) {
+					static J9_UNMODIFIABLE_CLASS_ANNOTATION_DATA annotBytes = {
+						(char)1, /* tag byte for UTF8 in the constant pool */
+						(char)(LITERAL_STRLEN(J9_UNMODIFIABLE_CLASS_ANNOTATION) >> 8), /* high byte of size (big endian) */
+						(char)(LITERAL_STRLEN(J9_UNMODIFIABLE_CLASS_ANNOTATION) & 0xFF), /* low byte of size (big endian) */
+						J9_UNMODIFIABLE_CLASS_ANNOTATION /* UTF8 data */
+					};
+					UDATA scanSize = annotationLength;
+					U_8 *scanBytes = (U_8*)&annotBytes;
+					do {
+						if (*scanBytes++ != *classData++) {
+							goto notFound;
+						}
+						scanSize -= 1;
+					} while (0 != scanSize);
+					modifiable = FALSE;
+					break;
+notFound: ;
+				}
+			}
+		}
 	}
-
-	return result;
+	return modifiable;
 }
 
 

runtime/oti/j9.h

@@ -341,4 +341,26 @@ static const struct { \
 #define J9_SHARED_CACHE_DEFAULT_BOOT_SHARING(vm) FALSE
 #endif /* defined(OPENJ9_BUILD) */
 
+/* Annotation name which indicates that a class is not allowed to be modified by
+ * JVMTI ClassFileLoadHook or RedefineClasses.
+ */
+#define J9_UNMODIFIABLE_CLASS_ANNOTATION "Lcom/ibm/oti/vm/J9UnmodifiableClass;"
+
+typedef struct {
+	char tag;
+	char zero;
+	char size;
+	char data[LITERAL_STRLEN(J9_UNMODIFIABLE_CLASS_ANNOTATION)];
+} J9_UNMODIFIABLE_CLASS_ANNOTATION_DATA;
+
+#if defined(__cplusplus)
+static_assert((sizeof(J9_UNMODIFIABLE_CLASS_ANNOTATION_DATA) == (3 + LITERAL_STRLEN(J9_UNMODIFIABLE_CLASS_ANNOTATION))), "Annotation structure is not packed correctly");
+/* '/' is the lowest numbered character which appears in the annotation name (assume
+ * that no '$' exists in there). The name length must be smaller than '/' in order
+ * to ensure that there are no overlapping substrings which would mandate a more
+ * complex matching algorithm.
+ */
+static_assert((LITERAL_STRLEN(J9_UNMODIFIABLE_CLASS_ANNOTATION) < (size_t)'/'), "Annotation contains invalid characters");
+#endif /* __cplusplus */
+
 #endif /* J9_H */

runtime/oti/j9javaaccessflags.h

@@ -47,6 +47,7 @@
 #define J9AccClassHasBeenOverridden 0x100000
 #define J9AccClassHasClinit 0x4000000
 #define J9AccClassHasEmptyFinalize 0x200000
+#define J9AccClassIsUnmodifiable 0x400000
 #define J9AccClassHasFinalFields 0x2000000
 #define J9AccClassHasJDBCNatives 0x400000
 #define J9AccClassHasNonStaticNonAbstractMethods 0x8000000

runtime/oti/j9modifiers_api.h

@@ -64,6 +64,7 @@
 #define J9ROMCLASS_FINALIZE_NEEDED(romClass)	_J9ROMCLASS_J9MODIFIER_IS_SET((romClass), J9AccClassFinalizeNeeded)
 #define J9ROMCLASS_IS_CLONEABLE(romClass)		_J9ROMCLASS_J9MODIFIER_IS_SET((romClass), J9AccClassCloneable)
 #define J9ROMCLASS_ANNOTATION_REFERS_DOUBLE_SLOT_ENTRY(romClass)	_J9ROMCLASS_J9MODIFIER_IS_SET((romClass), J9AccClassAnnnotionRefersDoubleSlotEntry)
+#define J9ROMCLASS_IS_UNMODIFIABLE(romClass)	_J9ROMCLASS_J9MODIFIER_IS_SET((romClass), J9AccClassIsUnmodifiable)
 
 /* 
  * Note that resolvefield ignores this flag if the cache line size cannot be determined.