jdk/src/share/classes/sun/security/ssl/HandshakeHash.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/security/ssl/HandshakeHash.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,248 @@
+/*
+ * Copyright 2002-2007 Sun Microsystems, 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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+
+package sun.security.ssl;
+
+import java.security.*;
+
+/**
+ * Abstraction for the SSL/TLS hash of all handshake messages that is
+ * maintained to verify the integrity of the negotiation. Internally,
+ * it consists of an MD5 and an SHA1 digest. They are used in the client
+ * and server finished messages and in certificate verify messages (if sent).
+ *
+ * This class transparently deals with cloneable and non-cloneable digests.
+ *
+ */
+final class HandshakeHash {
+
+    private final MessageDigest md5, sha;
+
+    /**
+     * Create a new HandshakeHash. needCertificateVerify indicates whether
+     * a hash for the certificate verify message is required.
+     */
+    HandshakeHash(boolean needCertificateVerify) {
+        int n = needCertificateVerify ? 3 : 2;
+        try {
+            md5 = CloneableDigest.getDigest("MD5", n);
+            sha = CloneableDigest.getDigest("SHA", n);
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException
+                        ("Algorithm MD5 or SHA not available", e);
+
+        }
+    }
+
+    void update(byte b) {
+        md5.update(b);
+        sha.update(b);
+    }
+
+    void update(byte[] b, int offset, int len) {
+        md5.update(b, offset, len);
+        sha.update(b, offset, len);
+    }
+
+    /**
+     * Reset the remaining digests. Note this does *not* reset the numbe of
+     * digest clones that can be obtained. Digests that have already been
+     * cloned and are gone remain gone.
+     */
+    void reset() {
+        md5.reset();
+        sha.reset();
+    }
+
+    /**
+     * Return a new MD5 digest updated with all data hashed so far.
+     */
+    MessageDigest getMD5Clone() {
+        return cloneDigest(md5);
+    }
+
+    /**
+     * Return a new SHA digest updated with all data hashed so far.
+     */
+    MessageDigest getSHAClone() {
+        return cloneDigest(sha);
+    }
+
+    private static MessageDigest cloneDigest(MessageDigest digest) {
+        try {
+            return (MessageDigest)digest.clone();
+        } catch (CloneNotSupportedException e) {
+            // cannot occur for digests generated via CloneableDigest
+            throw new RuntimeException("Could not clone digest", e);
+        }
+    }
+
+}
+
+/**
+ * A wrapper for MessageDigests that simulates cloning of non-cloneable
+ * digests. It uses the standard MessageDigest API and therefore can be used
+ * transparently in place of a regular digest.
+ *
+ * Note that we extend the MessageDigest class directly rather than
+ * MessageDigestSpi. This works because MessageDigest was originally designed
+ * this way in the JDK 1.1 days which allows us to avoid creating an internal
+ * provider.
+ *
+ * It can be "cloned" a limited number of times, which is specified at
+ * construction time. This is achieved by internally maintaining n digests
+ * in parallel. Consequently, it is only 1/n-th times as fast as the original
+ * digest.
+ *
+ * Example:
+ *   MessageDigest md = CloneableDigest.getDigest("SHA", 2);
+ *   md.update(data1);
+ *   MessageDigest md2 = (MessageDigest)md.clone();
+ *   md2.update(data2);
+ *   byte[] d1 = md2.digest(); // digest of data1 || data2
+ *   md.update(data3);
+ *   byte[] d2 = md.digest();  // digest of data1 || data3
+ *
+ * This class is not thread safe.
+ *
+ */
+final class CloneableDigest extends MessageDigest implements Cloneable {
+
+    /**
+     * The individual MessageDigests. Initially, all elements are non-null.
+     * When clone() is called, the non-null element with the maximum index is
+     * returned and the array element set to null.
+     *
+     * All non-null element are always in the same state.
+     */
+    private final MessageDigest[] digests;
+
+    private CloneableDigest(MessageDigest digest, int n, String algorithm)
+            throws NoSuchAlgorithmException {
+        super(algorithm);
+        digests = new MessageDigest[n];
+        digests[0] = digest;
+        for (int i = 1; i < n; i++) {
+            digests[i] = JsseJce.getMessageDigest(algorithm);
+        }
+    }
+
+    /**
+     * Return a MessageDigest for the given algorithm that can be cloned the
+     * specified number of times. If the default implementation supports
+     * cloning, it is returned. Otherwise, an instance of this class is
+     * returned.
+     */
+    static MessageDigest getDigest(String algorithm, int n)
+            throws NoSuchAlgorithmException {
+        MessageDigest digest = JsseJce.getMessageDigest(algorithm);
+        try {
+            digest.clone();
+            // already cloneable, use it
+            return digest;
+        } catch (CloneNotSupportedException e) {
+            return new CloneableDigest(digest, n, algorithm);
+        }
+    }
+
+    /**
+     * Check if this object is still usable. If it has already been cloned the
+     * maximum number of times, there are no digests left and this object can no
+     * longer be used.
+     */
+    private void checkState() {
+        // XXX handshaking currently doesn't stop updating hashes...
+        // if (digests[0] == null) {
+        //     throw new IllegalStateException("no digests left");
+        // }
+    }
+
+    protected int engineGetDigestLength() {
+        checkState();
+        return digests[0].getDigestLength();
+    }
+
+    protected void engineUpdate(byte b) {
+        checkState();
+        for (int i = 0; (i < digests.length) && (digests[i] != null); i++) {
+            digests[i].update(b);
+        }
+    }
+
+    protected void engineUpdate(byte[] b, int offset, int len) {
+        checkState();
+        for (int i = 0; (i < digests.length) && (digests[i] != null); i++) {
+            digests[i].update(b, offset, len);
+        }
+    }
+
+    protected byte[] engineDigest() {
+        checkState();
+        byte[] digest = digests[0].digest();
+        digestReset();
+        return digest;
+    }
+
+    protected int engineDigest(byte[] buf, int offset, int len)
+            throws DigestException {
+        checkState();
+        int n = digests[0].digest(buf, offset, len);
+        digestReset();
+        return n;
+    }
+
+    /**
+     * Reset all digests after a digest() call. digests[0] has already been
+     * implicitly reset by the digest() call and does not need to be reset
+     * again.
+     */
+    private void digestReset() {
+        for (int i = 1; (i < digests.length) && (digests[i] != null); i++) {
+            digests[i].reset();
+        }
+    }
+
+    protected void engineReset() {
+        checkState();
+        for (int i = 0; (i < digests.length) && (digests[i] != null); i++) {
+            digests[i].reset();
+        }
+    }
+
+    public Object clone() {
+        checkState();
+        for (int i = digests.length - 1; i >= 0; i--) {
+            if (digests[i] != null) {
+                MessageDigest digest = digests[i];
+                digests[i] = null;
+                return digest;
+            }
+        }
+        // cannot occur
+        throw new InternalError();
+    }
+
+}