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/util/ArrayList/ArrayManagement.java

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+/*
+ * Copyright 2016 Google, Inc.  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
+ * @bug 8146568
+ * @summary brittle white box test of internal array management
+ * @modules java.base/java.util:open
+ * @run testng ArrayManagement
+ */
+
+import java.lang.reflect.Field;
+import java.util.AbstractList;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.SplittableRandom;
+
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+public class ArrayManagement {
+    static final int DEFAULT_CAPACITY = 10;
+    static final Field ELEMENT_DATA;
+    static final Field MODCOUNT;
+    static final SplittableRandom rnd = new SplittableRandom();
+
+    static {
+        try {
+            ELEMENT_DATA = ArrayList.class.getDeclaredField("elementData");
+            ELEMENT_DATA.setAccessible(true);
+            MODCOUNT = AbstractList.class.getDeclaredField("modCount");
+            MODCOUNT.setAccessible(true);
+        } catch (ReflectiveOperationException huh) {
+            throw new AssertionError(huh);
+        }
+    }
+
+    static Object[] elementData(ArrayList<?> list) {
+        try {
+            return (Object[]) ELEMENT_DATA.get(list);
+        } catch (ReflectiveOperationException huh) {
+            throw new AssertionError(huh);
+        }
+    }
+
+    static int modCount(ArrayList<?> list) {
+        try {
+            return MODCOUNT.getInt(list);
+        } catch (ReflectiveOperationException huh) {
+            throw new AssertionError(huh);
+        }
+    }
+
+    static int capacity(ArrayList<?> list) {
+        return elementData(list).length;
+    }
+
+    static int newCapacity(int oldCapacity) {
+        return oldCapacity + (oldCapacity >> 1);
+    }
+
+    static void ensureCapacity(ArrayList<Object> list, int capacity) {
+        int oldCapacity = capacity(list);
+        int oldModCount = modCount(list);
+        list.ensureCapacity(capacity);
+        assertTrue(capacity(list) >= capacity || capacity(list) == 0);
+        assertEquals(modCount(list),
+                     (capacity(list) == oldCapacity)
+                     ? oldModCount
+                     : oldModCount + 1);
+    }
+
+    static List<Object> singletonList() {
+        return Collections.singletonList(Boolean.TRUE);
+    }
+
+    /** Opportunistically randomly test various add operations. */
+    static void addOneElement(ArrayList<Object> list) {
+        int size = list.size();
+        int modCount = modCount(list);
+        switch (rnd.nextInt(4)) {
+        case 0: assertTrue(list.add(Boolean.TRUE)); break;
+        case 1: list.add(size, Boolean.TRUE); break;
+        case 2: assertTrue(list.addAll(singletonList())); break;
+        case 3: assertTrue(list.addAll(size, singletonList())); break;
+        default: throw new AssertionError();
+        }
+        assertEquals(modCount(list), modCount + 1);
+        assertEquals(list.size(), size + 1);
+    }
+
+    @Test public void defaultCapacity() {
+        ArrayList<Object> list = new ArrayList<>();
+        assertEquals(capacity(new ArrayList<Object>()), 0);
+        for (int i = 0; i < DEFAULT_CAPACITY; i++) {
+            addOneElement(list);
+            assertEquals(capacity(list), DEFAULT_CAPACITY);
+        }
+        addOneElement(list);
+        assertEquals(capacity(list), newCapacity(DEFAULT_CAPACITY));
+    }
+
+    @Test public void defaultCapacityEnsureCapacity() {
+        ArrayList<Object> list = new ArrayList<>();
+        for (int i = 0; i <= DEFAULT_CAPACITY; i++) {
+            ensureCapacity(list, i);     // no-op!
+            assertEquals(capacity(list), 0);
+        }
+        for (int i = 0; i < DEFAULT_CAPACITY; i++) {
+            addOneElement(list);
+            assertEquals(capacity(list), DEFAULT_CAPACITY);
+        }
+        addOneElement(list);
+        assertEquals(capacity(list), newCapacity(DEFAULT_CAPACITY));
+        {
+            int capacity = capacity(list);
+            ensureCapacity(list, capacity + 1);
+            assertEquals(capacity(list), newCapacity(capacity));
+        }
+        {
+            int capacity = capacity(list);
+            ensureCapacity(list, 3 * capacity);
+            assertEquals(capacity(list), 3 * capacity);
+        }
+    }
+
+    @Test public void ensureCapacityBeyondDefaultCapacity() {
+        ArrayList<Object> list = new ArrayList<>();
+        list.ensureCapacity(DEFAULT_CAPACITY + 1);
+        assertEquals(capacity(list), DEFAULT_CAPACITY + 1);
+        for (int i = 0; i < DEFAULT_CAPACITY + 1; i++) {
+            addOneElement(list);
+            assertEquals(capacity(list), DEFAULT_CAPACITY + 1);
+        }
+        addOneElement(list);
+        assertEquals(capacity(list), newCapacity(DEFAULT_CAPACITY + 1));
+    }
+
+    @Test public void explicitZeroCapacity() {
+        ArrayList<Object> list = new ArrayList<>(0);
+        assertEquals(capacity(list), 0);
+        addOneElement(list);
+        assertEquals(capacity(list), 1);
+        addOneElement(list);
+        assertEquals(capacity(list), 2);
+        addOneElement(list);
+        assertEquals(capacity(list), 3);
+        addOneElement(list);
+        assertEquals(capacity(list), 4);
+        addOneElement(list);
+        assertEquals(capacity(list), 6);
+        addOneElement(list);
+        assertEquals(capacity(list), 6);
+        addOneElement(list);
+        assertEquals(capacity(list), 9);
+        list.clear();
+        assertEquals(capacity(list), 9);
+    }
+
+    @Test public void explicitLargeCapacity() {
+        int n = DEFAULT_CAPACITY * 3;
+        ArrayList<Object> list = new ArrayList<>(n);
+        assertEquals(capacity(list), n);
+        ensureCapacity(list, 0);
+        ensureCapacity(list, n);
+        for (int i = 0; i < n; i++) addOneElement(list);
+        assertEquals(capacity(list), n);
+
+        addOneElement(list);
+        assertEquals(capacity(list), newCapacity(n));
+    }
+
+    @Test public void emptyArraysAreShared() {
+        assertSame(elementData(new ArrayList<Object>()),
+                   elementData(new ArrayList<Object>()));
+        assertSame(elementData(new ArrayList<Object>(0)),
+                   elementData(new ArrayList<Object>(0)));
+    }
+
+    @Test public void emptyArraysDifferBetweenDefaultAndExplicit() {
+        assertNotSame(elementData(new ArrayList<Object>()),
+                      elementData(new ArrayList<Object>(0)));
+    }
+
+    @Test public void negativeCapacity() {
+        for (int capacity : new int[] { -1, Integer.MIN_VALUE }) {
+            try {
+                new ArrayList<Object>(capacity);
+                fail("should throw");
+            } catch (IllegalArgumentException success) {}
+        }
+    }
+}