--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/security/ssl/ClientHandshakeContext.java	Mon Jun 25 13:41:39 2018 -0700
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2018, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.security.ssl;
+
+import java.io.IOException;
+import java.security.cert.X509Certificate;
+
+import sun.security.ssl.ClientHello.ClientHelloMessage;
+
+class ClientHandshakeContext extends HandshakeContext {
+    /*
+     * Allow unsafe server certificate change?
+     *
+     * Server certificate change during SSL/TLS renegotiation may be considered
+     * unsafe, as described in the Triple Handshake attacks:
+     *
+     *     https://secure-resumption.com/tlsauth.pdf
+     *
+     * Endpoint identification (See
+     * SSLParameters.getEndpointIdentificationAlgorithm()) is a pretty nice
+     * guarantee that the server certificate change in renegotiation is legal.
+     * However, endpoint identification is only enabled for HTTPS and LDAP
+     * over SSL/TLS by default.  It is not enough to protect SSL/TLS
+     * connections other than HTTPS and LDAP.
+     *
+     * The renegotiation indication extension (See RFC 5746) is a pretty
+     * strong guarantee that the endpoints on both client and server sides
+     * are identical on the same connection.  However, the Triple Handshake
+     * attacks can bypass this guarantee if there is a session-resumption
+     * handshake between the initial full handshake and the renegotiation
+     * full handshake.
+     *
+     * Server certificate change may be unsafe and should be restricted if
+     * endpoint identification is not enabled and the previous handshake is
+     * a session-resumption abbreviated initial handshake, unless the
+     * identities represented by both certificates can be regraded as the
+     * same (See isIdentityEquivalent()).
+     *
+     * Considering the compatibility impact and the actual requirements to
+     * support server certificate change in practice, the system property,
+     * jdk.tls.allowUnsafeServerCertChange, is used to define whether unsafe
+     * server certificate change in renegotiation is allowed or not.  The
+     * default value of the system property is "false".  To mitigate the
+     * compatibility impact, applications may want to set the system
+     * property to "true" at their own risk.
+     *
+     * If the value of the system property is "false", server certificate
+     * change in renegotiation after a session-resumption abbreviated initial
+     * handshake is restricted (See isIdentityEquivalent()).
+     *
+     * If the system property is set to "true" explicitly, the restriction on
+     * server certificate change in renegotiation is disabled.
+     */
+    static final boolean allowUnsafeServerCertChange =
+            Utilities.getBooleanProperty(
+                    "jdk.tls.allowUnsafeServerCertChange", false);
+
+    /*
+     * the reserved server certificate chain in previous handshaking
+     *
+     * The server certificate chain is only reserved if the previous
+     * handshake is a session-resumption abbreviated initial handshake.
+     */
+    X509Certificate[] reservedServerCerts = null;
+
+    X509Certificate[] deferredCerts;
+
+    ClientHelloMessage initialClientHelloMsg = null;
+
+    ClientHandshakeContext(SSLContextImpl sslContext,
+            TransportContext conContext) throws IOException {
+        super(sslContext, conContext);
+    }
+
+    @Override
+    void kickstart() throws IOException {
+        if (kickstartMessageDelivered) {
+            return;
+        }
+
+        SSLHandshake.kickstart(this);
+        kickstartMessageDelivered = true;
+    }
+}