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.

test/jdk/java/lang/String/nativeEncoding/StringPlatformChars.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2017, 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
+ * @requires !jdk.static
+ * @run main/othervm/native -Xcheck:jni StringPlatformChars
+ */
+import java.util.Arrays;
+
+public class StringPlatformChars {
+
+    private static final String JNU_ENCODING = System.getProperty("sun.jnu.encoding");
+
+    public static void main(String... args) throws Exception {
+        System.out.println("sun.jnu.encoding: " + JNU_ENCODING);
+        System.loadLibrary("stringPlatformChars");
+
+        // Test varying lengths, provoking different allocation paths
+        StringBuilder unicodeSb = new StringBuilder();
+        StringBuilder asciiSb = new StringBuilder();
+        StringBuilder latinSb = new StringBuilder();
+
+        for (int i = 0; i < 2000; i++) {
+            unicodeSb.append('\uFEFE');
+            testString(unicodeSb.toString());
+
+            asciiSb.append('x');
+            testString(asciiSb.toString());
+
+            latinSb.append('\u00FE');
+            testString(latinSb.toString());
+
+            testString(latinSb.toString() + asciiSb.toString() + unicodeSb.toString());
+        }
+
+        // Exhaustively test simple Strings made up of all possible chars:
+        for (char c = '\u0001'; c < Character.MAX_VALUE; c++) {
+            testString(String.valueOf(c));
+        }
+        // Special case: \u0000 is treated as end-of-string in the native code,
+        // so strings with it should be truncated:
+        if (getBytes("\u0000abcdef").length != 0 ||
+            getBytes("a\u0000bcdef").length != 1) {
+            System.out.println("Mismatching values for strings including \\u0000");
+            throw new AssertionError();
+        }
+    }
+
+    private static void testString(String s) throws Exception {
+        byte[] nativeBytes = getBytes(s);
+        byte[] stringBytes = s.getBytes(JNU_ENCODING);
+
+        if (!Arrays.equals(nativeBytes, stringBytes)) {
+            System.out.println("Mismatching values for: '" + s + "' " + Arrays.toString(s.chars().toArray()));
+            System.out.println("Native: " + Arrays.toString(nativeBytes));
+            System.out.println("String: " + Arrays.toString(stringBytes));
+            throw new AssertionError(s);
+        }
+
+        String javaNewS = new String(nativeBytes, JNU_ENCODING);
+        String nativeNewS = newString(nativeBytes);
+        if (!javaNewS.equals(nativeNewS)) {
+            System.out.println("New string via native doesn't match via java: '" + javaNewS + "' and '" + nativeNewS + "'");
+            throw new AssertionError(s);
+        }
+    }
+
+    static native byte[] getBytes(String string);
+
+    static native String newString(byte[] bytes);
+}