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/StringBuilder/HugeCapacity.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2016, 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.
+ */
+
+import jdk.internal.util.ArraysSupport;
+
+import java.util.Arrays;
+
+/**
+ * @test
+ * @bug 8149330 8218227 8351443
+ * @summary Capacity should not get close to Integer.MAX_VALUE unless
+ *          necessary
+ * @modules java.base/jdk.internal.util
+ * @requires (sun.arch.data.model == "64" & os.maxMemory >= 8G)
+ * @run main/othervm -Xms8G -Xmx8G -XX:-CompactStrings -Xlog:gc HugeCapacity false
+ * @run main/othervm -Xms8G -Xmx8G -XX:+CompactStrings -Xlog:gc HugeCapacity true
+ */
+
+public class HugeCapacity {
+    private static int failures = 0;
+
+    public static void main(String[] args) {
+        if (args.length == 0) {
+           throw new IllegalArgumentException("Need the argument");
+        }
+        boolean isCompact = Boolean.parseBoolean(args[0]);
+
+        testLatin1(isCompact);
+        testUtf16();
+        testHugeInitialString();
+        testHugeInitialCharSequence();
+        testHugePlus(isCompact);
+        if (failures > 0) {
+            throw new RuntimeException(failures + " tests failed");
+        }
+    }
+
+    private static void testLatin1(boolean isCompact) {
+        try {
+            int divisor = isCompact ? 2 : 4;
+            StringBuilder sb = new StringBuilder();
+            sb.ensureCapacity(Integer.MAX_VALUE / divisor);
+            sb.ensureCapacity(Integer.MAX_VALUE / divisor + 1);
+        } catch (OutOfMemoryError oom) {
+            oom.printStackTrace();
+            failures++;
+        }
+    }
+
+    private static void testUtf16() {
+        try {
+            StringBuilder sb = new StringBuilder();
+            sb.append('\u042b');
+            sb.ensureCapacity(Integer.MAX_VALUE / 4);
+            sb.ensureCapacity(Integer.MAX_VALUE / 4 + 1);
+        } catch (OutOfMemoryError oom) {
+            oom.printStackTrace();
+            failures++;
+        }
+    }
+
+    private static void testHugeInitialString() {
+        try {
+            String str = "Z".repeat(ArraysSupport.SOFT_MAX_ARRAY_LENGTH);
+            StringBuilder sb = new StringBuilder(str);
+        } catch (OutOfMemoryError ignore) {
+        } catch (Throwable unexpected) {
+            unexpected.printStackTrace();
+            failures++;
+        }
+    }
+
+    private static void testHugeInitialCharSequence() {
+        try {
+            CharSequence seq = new MyHugeCharSeq();
+            StringBuilder sb = new StringBuilder(seq);
+        } catch (OutOfMemoryError ignore) {
+        } catch (Throwable unexpected) {
+            unexpected.printStackTrace();
+            failures++;
+        }
+    }
+
+    private static class MyHugeCharSeq implements CharSequence {
+        public char charAt(int i) {
+            throw new UnsupportedOperationException();
+        }
+        public int length() { return Integer.MAX_VALUE; }
+        public CharSequence subSequence(int st, int e) {
+            throw new UnsupportedOperationException();
+        }
+        public String toString() { return ""; }
+    }
+
+    // Test creating and appending the max size string for -XX:+CompactStrings and -XX:-CompactStrings
+    private static void testHugePlus(boolean isCompact) {
+        int repeatCount = (isCompact) ? Integer.MAX_VALUE / 2 - 1 : Integer.MAX_VALUE / 4 - 1;
+        char[] chars = new char[repeatCount];
+        char[] aChar = {'A', '\uff21'};
+        for (char ch : aChar) {
+            try {
+                int size = (ch > 0xff) ? repeatCount / 2 : repeatCount;
+                Arrays.fill(chars, 0, size, ch);
+                StringBuilder b = new StringBuilder(0);
+                b.append(chars, 0, size);
+                b.append(chars, 0, size);
+            } catch (Throwable unexpected) {
+                unexpected.printStackTrace();
+                failures++;
+            }
+        }
+    }
+}