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8186654: Poor quality of sun.security.util.Cache.EqualByteArray.hashCode()

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Reviewed-by: coffeys
This commit is contained in:
Ivan Gerasimov 2017-10-04 01:08:36 -07:00
parent 4560687884
commit 9c1b0103b3
2 changed files with 47 additions and 7 deletions
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10
src/java.base/share/classes/sun/security/util/Cache.java
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@ -164,7 +164,7 @@ public abstract class Cache<K,V> {
public static class EqualByteArray { public static class EqualByteArray {
private final byte[] b; private final byte[] b;
private volatile int hash; private int hash;
public EqualByteArray(byte[] b) { public EqualByteArray(byte[] b) {
this.b = b; this.b = b;
@ -172,12 +172,8 @@ public abstract class Cache<K,V> {
public int hashCode() { public int hashCode() {
int h = hash; int h = hash;
if (h == 0) { if (h == 0 && b.length > 0) {
h = b.length + 1; hash = h = Arrays.hashCode(b);
for (int i = 0; i < b.length; i++) {
h += (b[i] & 0xff) * 37;
}
hash = h;
} }
return h; return h;
} }

44
test/jdk/sun/security/util/Cache/EbaHash.java Normal file
View file

@ -0,0 +1,44 @@
/*
* Copyright (c) 2017, 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
* @bug 8186654
* @summary Transpositions of an array result in the same
* EqualByteArray.hashCode()
* @modules java.base/sun.security.util
*/
import sun.security.util.Cache;
public class EbaHash {
public static void main(String[] args) throws Throwable {
int h1 = new Cache.EqualByteArray(new byte[] {1,2,3}).hashCode();
int h2 = new Cache.EqualByteArray(new byte[] {2,3,1}).hashCode();
int h3 = new Cache.EqualByteArray(new byte[] {3,1,2}).hashCode();
if (h1 == h2 && h2 == h3) {
throw new RuntimeException("Transpositions of an array" +
" resulted in the same hashCode()");
}
}
}