# HG changeset patch
# User bpb
# Date 1511465606 0
# Node ID 72f71c6b2bbc077bc160cdd0243e6cf612a6a018
# Parent  4fcf12d3efe19d2c9134c79a7251a7f655db0b1a
8016252: More defensive HashSet.readObject
Summary: Add data validation checks in readObject().
Reviewed-by: alanb, mduigou, chegar
Contributed-by: Brian Burkhalter <brian.burkhalter@oracle.com>

diff -r 4fcf12d3efe1 -r 72f71c6b2bbc src/share/classes/java/util/HashSet.java
--- a/src/share/classes/java/util/HashSet.java	Thu Nov 23 03:37:33 2017 +0000
+++ b/src/share/classes/java/util/HashSet.java	Thu Nov 23 19:33:26 2017 +0000
@@ -25,6 +25,8 @@
 
 package java.util;
 
+import java.io.InvalidObjectException;
+
 /**
  * This class implements the <tt>Set</tt> interface, backed by a hash table
  * (actually a <tt>HashMap</tt> instance).  It makes no guarantees as to the
@@ -293,16 +295,37 @@
         // Read in any hidden serialization magic
         s.defaultReadObject();
 
-        // Read in HashMap capacity and load factor and create backing HashMap
+        // Read capacity and verify non-negative.
         int capacity = s.readInt();
+        if (capacity < 0) {
+            throw new InvalidObjectException("Illegal capacity: " +
+                                             capacity);
+        }
+
+        // Read load factor and verify positive and non NaN.
         float loadFactor = s.readFloat();
+        if (loadFactor <= 0 || Float.isNaN(loadFactor)) {
+            throw new InvalidObjectException("Illegal load factor: " +
+                                             loadFactor);
+        }
+
+        // Read size and verify non-negative.
+        int size = s.readInt();
+        if (size < 0) {
+            throw new InvalidObjectException("Illegal size: " +
+                                             size);
+        }
+
+        // Set the capacity according to the size and load factor ensuring that
+        // the HashMap is at least 25% full but clamping to maximum capacity.
+        capacity = (int) Math.min(size * Math.min(1 / loadFactor, 4.0f),
+                HashMap.MAXIMUM_CAPACITY);
+
+        // Create backing HashMap
         map = (((HashSet)this) instanceof LinkedHashSet ?
                new LinkedHashMap<E,Object>(capacity, loadFactor) :
                new HashMap<E,Object>(capacity, loadFactor));
 
-        // Read in size
-        int size = s.readInt();
-
         // Read in all elements in the proper order.
         for (int i=0; i<size; i++) {
             E e = (E) s.readObject();
diff -r 4fcf12d3efe1 -r 72f71c6b2bbc test/java/util/HashSet/Serialization.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/java/util/HashSet/Serialization.java	Thu Nov 23 19:33:26 2017 +0000
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2013, 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 java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+/*
+ * @test
+ * @bug 8016252
+ * @summary Verify that a serialized HashSet may successfully be deserialized.
+ */
+public class Serialization {
+
+    private static final int NUM_SETS = 43;
+    private static final int MAX_CAPACITY = 257;
+    private static final float MAX_LOAD_FACTOR = 100.0F;
+
+    private static final Random rnd = ThreadLocalRandom.current();
+
+    private static HashSet<Integer> createHashSet() {
+        int capacity = rnd.nextInt(MAX_CAPACITY);
+        float loadFactor = Float.MIN_VALUE + rnd.nextFloat()*MAX_LOAD_FACTOR;
+        HashSet<Integer> hashSet = new HashSet<Integer>(capacity, loadFactor);
+        float multiplier = 2*rnd.nextFloat(); // range [0,2]
+        int size = (int)(capacity*loadFactor*multiplier);
+        for (int i = 0; i < size; i++) {
+            hashSet.add(rnd.nextInt());
+        }
+        return hashSet;
+    }
+
+    private static HashSet<Integer> serDeser(HashSet<Integer> hashSet) throws IOException, ClassNotFoundException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ObjectOutputStream oos = new ObjectOutputStream(baos);
+        oos.writeObject(hashSet);
+        oos.flush();
+
+        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        ObjectInputStream ois = new ObjectInputStream(bais);
+        HashSet<Integer> result = (HashSet<Integer>)ois.readObject();
+
+        oos.close();
+        ois.close();
+
+        return result;
+    }
+
+    private static void printHashSet(HashSet<Integer> hashSet) {
+        System.err.println("Size: "+hashSet.size());
+        for (Object o : hashSet) {
+            System.err.println(o);
+        }
+    }
+
+    public static void main(String[] args) {
+        int failures = 0;
+
+        for (int i = 0; i < NUM_SETS; i++) {
+            HashSet<Integer> hashSet = createHashSet();
+
+            HashSet<Integer> result = null;
+            try {
+                result = serDeser(hashSet);
+            } catch (IOException ioe) {
+                System.err.println(ioe);
+                failures++;
+            } catch (ClassNotFoundException cnfe) {
+                System.err.println(cnfe);
+                failures++;
+            }
+
+            if (!hashSet.equals(result)) {
+                System.err.println("Unequal HashSets!");
+                printHashSet(hashSet);
+                System.err.println();
+                failures++;
+            }
+        }
+
+        if (failures != 0) {
+            throw new RuntimeException("HashSet/Serialzation failed with "+
+                    failures+" failures!");
+        }
+    }
+}