8338888: SystemDictionary::class_name_symbol has incorrect length check

Reviewed-by: stuefe, kbarrett, coleenp

Author: David Holmes

src/hotspot/share/classfile/systemDictionary.cpp

@@ -261,17 +261,32 @@ Symbol* SystemDictionary::class_name_symbol(const char* name, Symbol* exception,
   if (name == nullptr) {
     THROW_MSG_NULL(exception, "No class name given");
   }
-  if ((int)strlen(name) > Symbol::max_length()) {
+  size_t name_len = strlen(name);
+  if (name_len > static_cast<size_t>(Symbol::max_length())) {
     // It's impossible to create this class;  the name cannot fit
-    // into the constant pool.
-    Exceptions::fthrow(THREAD_AND_LOCATION, exception,
-                       "Class name exceeds maximum length of %d: %s",
-                       Symbol::max_length(),
-                       name);
+    // into the constant pool. If necessary report an abridged name
+    // in the exception message.
+    if (name_len > static_cast<size_t>(MaxStringPrintSize)) {
+      Exceptions::fthrow(THREAD_AND_LOCATION, exception,
+                         "Class name exceeds maximum length of %d: %.*s ... (%zu characters omitted) ... %.*s",
+                         Symbol::max_length(),
+                         MaxStringPrintSize / 2,
+                         name,
+                         name_len - 2 * (MaxStringPrintSize / 2), // allows for odd value
+                         MaxStringPrintSize / 2,
+                         name + name_len - MaxStringPrintSize / 2);
+    }
+    else {
+      Exceptions::fthrow(THREAD_AND_LOCATION, exception,
+                         "Class name exceeds maximum length of %d: %s",
+                         Symbol::max_length(),
+                         name);
+    }
     return nullptr;
   }
   // Callers should ensure that the name is never an illegal UTF8 string.
-  assert(UTF8::is_legal_utf8((const unsigned char*)name, (int)strlen(name), false),
+  assert(UTF8::is_legal_utf8((const unsigned char*)name,
+                             static_cast<int>(name_len), false),
          "Class name is not a valid utf8 string.");
 
   // Make a new symbol for the class name.

test/hotspot/jtreg/runtime/exceptionMsgs/NoClassDefFoundError/NoClassDefFoundErrorTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 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
@@ -23,21 +23,27 @@
 
 /*
  * @test
- * @bug 8056900
+ * @bug 8056900 8338888
  * @summary Verifies message returned with NoClassDefFoundError exception.
  * @library /test/lib
  * @modules java.base/jdk.internal.misc
  *          java.compiler
- * @run main/native NoClassDefFoundErrorTest
+ * @run main/native/othervm -Xlog:exceptions=info NoClassDefFoundErrorTest
  */
 
 import jdk.test.lib.compiler.InMemoryJavaCompiler;
 import jdk.internal.misc.Unsafe;
 
 public class NoClassDefFoundErrorTest {
 
+    // Use the specified name
     static native void callDefineClass(String className);
     static native void callFindClass(String className);
+    // Use a name longer than a Java string - returns false
+    // if native allocation failed.
+    static native boolean tryCallDefineClass();
+    static native boolean tryCallFindClass();
+
     static {
         System.loadLibrary("NoClassDefFoundErrorTest");
     }
@@ -54,7 +60,7 @@ public static void main(String args[]) throws Exception {
             tooBigClassName = tooBigClassName.append(tooBigClassName);
         }
 
-        // Test JVM_DefineClass() with long name.
+        System.out.println("Test JVM_DefineClass() with long name");
         try {
             unsafe.defineClass(tooBigClassName.toString(), klassbuf, 4, klassbuf.length - 4, null, null);
             throw new RuntimeException("defineClass did not throw expected NoClassDefFoundError");
@@ -64,7 +70,7 @@ public static void main(String args[]) throws Exception {
             }
         }
 
-        // Test JNI_DefineClass() with long name.
+        System.out.println("Test JNI_DefineClass() with long name");
         try {
             callDefineClass(tooBigClassName.toString());
             throw new RuntimeException("DefineClass did not throw expected NoClassDefFoundError");
@@ -74,17 +80,17 @@ public static void main(String args[]) throws Exception {
             }
         }
 
-        // Test JNI_FindClass() with long name.
+        System.out.println("Test JNI_FindClass() with long name");
         try {
             callFindClass(tooBigClassName.toString());
-            throw new RuntimeException("DefineClass did not throw expected NoClassDefFoundError");
+            throw new RuntimeException("FindClass did not throw expected NoClassDefFoundError");
         } catch (NoClassDefFoundError e) {
             if (!e.getMessage().contains("Class name exceeds maximum length of ")) {
                 throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
             }
         }
 
-        // Test JNI_FindClass() with null name.
+        System.out.println("Test JNI_FindClass() with null name");
         try {
             callFindClass(null);
             throw new RuntimeException("FindClass did not throw expected NoClassDefFoundError");
@@ -93,5 +99,31 @@ public static void main(String args[]) throws Exception {
                 throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
             }
         }
+
+        System.out.println("Test JNI_DefineClass() with giant name");
+        try {
+            if (tryCallDefineClass()) {
+                throw new RuntimeException("DefineClass did not throw expected NoClassDefFoundError");
+            } else {
+                System.out.println("Test skipped due to native allocation failure");
+            }
+        } catch (NoClassDefFoundError e) {
+            if (!e.getMessage().contains("Class name exceeds maximum length of ")) {
+                throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
+            }
+        }
+
+        System.out.println("Test JNI_FindClass() with giant name");
+        try {
+            if (tryCallFindClass()) {
+                throw new RuntimeException("FindClass did not throw expected NoClassDefFoundError");
+            } else {
+                System.out.println("Test skipped due to native allocation failure");
+            }
+        } catch (NoClassDefFoundError e) {
+            if (!e.getMessage().contains("Class name exceeds maximum length of ")) {
+                throw new RuntimeException("Wrong NoClassDefFoundError: " + e.getMessage());
+            }
+        }
     }
 }

test/hotspot/jtreg/runtime/exceptionMsgs/NoClassDefFoundError/libNoClassDefFoundErrorTest.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 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
@@ -22,6 +22,10 @@
  */
 
 #include <jni.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+
 
 JNIEXPORT void JNICALL
 Java_NoClassDefFoundErrorTest_callDefineClass(JNIEnv *env, jclass klass, jstring className) {
@@ -42,3 +46,34 @@ Java_NoClassDefFoundErrorTest_callFindClass(JNIEnv *env, jclass klass, jstring c
 }
 
 
+static char* giant_string() {
+    size_t len = ((size_t)INT_MAX) + 3;
+    char* c_name = malloc(len * sizeof(char));
+    if (c_name != NULL) {
+        memset(c_name, 'Y', len - 1);
+        c_name[len - 1] = '\0';
+    }
+    return c_name;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_NoClassDefFoundErrorTest_tryCallDefineClass(JNIEnv *env, jclass klass) {
+    char* c_name = giant_string();
+    if (c_name != NULL) {
+        (*env)->DefineClass(env, c_name, NULL, NULL, 0);
+        free(c_name);
+        return JNI_TRUE;
+    }
+    return JNI_FALSE;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_NoClassDefFoundErrorTest_tryCallFindClass(JNIEnv *env, jclass klass) {
+    char* c_name = giant_string();
+    if (c_name != NULL) {
+        jclass cls = (*env)->FindClass(env, c_name);
+        free(c_name);
+        return JNI_TRUE;
+    }
+    return JNI_FALSE;
+}