--- a/src/share/classes/sun/security/jgss/krb5/InitialToken.java	Thu Jun 18 10:38:21 2009 -0400
+++ b/src/share/classes/sun/security/jgss/krb5/InitialToken.java	Fri Jun 19 18:03:27 2009 +0800
@@ -33,6 +33,7 @@
 import java.net.Inet6Address;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
 import sun.security.krb5.*;
 import sun.security.jgss.HttpCaller;
 import sun.security.krb5.internal.Krb5;
@@ -219,43 +220,35 @@
                         "Incorrect checksum");
             }
 
-            byte[] remoteBindingBytes = new byte[CHECKSUM_BINDINGS_SIZE];
-            System.arraycopy(checksumBytes, 4, remoteBindingBytes, 0,
-                             CHECKSUM_BINDINGS_SIZE);
-
-            byte[] noBindings = new byte[CHECKSUM_BINDINGS_SIZE];
-            boolean tokenContainsBindings =
-                (!java.util.Arrays.equals(noBindings, remoteBindingBytes));
-
             ChannelBinding localBindings = context.getChannelBinding();
 
-            if (tokenContainsBindings ||
-                localBindings != null) {
+            // Ignore remote channel binding info when not requested at
+            // local side (RFC 4121 4.1.1.2: the acceptor MAY ignore...).
+            //
+            // All major krb5 implementors implement this "MAY",
+            // and some applications depend on it as a workaround
+            // for not having a way to negotiate the use of channel
+            // binding -- the initiator application always uses CB
+            // and hopes the acceptor will ignore the CB if the
+            // acceptor doesn't support CB.
+            if (localBindings != null) {
+                byte[] remoteBindingBytes = new byte[CHECKSUM_BINDINGS_SIZE];
+                System.arraycopy(checksumBytes, 4, remoteBindingBytes, 0,
+                                 CHECKSUM_BINDINGS_SIZE);
 
-                boolean badBindings = false;
-                String errorMessage = null;
-
-                if (tokenContainsBindings &&
-                    localBindings != null) {
+                byte[] noBindings = new byte[CHECKSUM_BINDINGS_SIZE];
+                if (!Arrays.equals(noBindings, remoteBindingBytes)) {
                     byte[] localBindingsBytes =
                         computeChannelBinding(localBindings);
-                    //              System.out.println("ChannelBinding hash: "
-                    //         + getHexBytes(localBindingsBytes));
-                    badBindings =
-                        (!java.util.Arrays.equals(localBindingsBytes,
-                                                remoteBindingBytes));
-                    errorMessage = "Bytes mismatch!";
-                } else if (localBindings == null) {
-                    errorMessage = "ChannelBinding not provided!";
-                    badBindings = true;
+                    if (!Arrays.equals(localBindingsBytes,
+                                                remoteBindingBytes)) {
+                        throw new GSSException(GSSException.BAD_BINDINGS, -1,
+                                               "Bytes mismatch!");
+                    }
                 } else {
-                    errorMessage = "Token missing ChannelBinding!";
-                    badBindings = true;
+                    throw new GSSException(GSSException.BAD_BINDINGS, -1,
+                                           "Token missing ChannelBinding!");
                 }
-
-                if (badBindings)
-                    throw new GSSException(GSSException.BAD_BINDINGS, -1,
-                                           errorMessage);
             }
 
             flags = readLittleEndian(checksumBytes, 20, 4);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/sun/security/krb5/auto/IgnoreChannelBinding.java	Fri Jun 19 18:03:27 2009 +0800
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2009 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 6851973
+ * @summary ignore incoming channel binding if acceptor does not set one
+ */
+
+import java.net.InetAddress;
+import org.ietf.jgss.ChannelBinding;
+import org.ietf.jgss.GSSException;
+import sun.security.jgss.GSSUtil;
+
+public class IgnoreChannelBinding {
+
+    public static void main(String[] args)
+            throws Exception {
+
+        new OneKDC(null).writeJAASConf();
+
+        Context c = Context.fromJAAS("client");
+        Context s = Context.fromJAAS("server");
+
+        // All silent
+        c.startAsClient(OneKDC.SERVER, GSSUtil.GSS_KRB5_MECH_OID);
+        s.startAsServer(GSSUtil.GSS_KRB5_MECH_OID);
+        Context.handshake(c, s);
+
+        // Initiator req, acceptor ignore
+        c.startAsClient(OneKDC.SERVER, GSSUtil.GSS_KRB5_MECH_OID);
+        c.x().setChannelBinding(new ChannelBinding(
+                InetAddress.getByName("client.rabbit.hole"),
+                InetAddress.getByName("host.rabbit.hole"),
+                new byte[0]
+                ));
+        s.startAsServer(GSSUtil.GSS_KRB5_MECH_OID);
+        Context.handshake(c, s);
+
+        // Both req, and match
+        c.startAsClient(OneKDC.SERVER, GSSUtil.GSS_KRB5_MECH_OID);
+        c.x().setChannelBinding(new ChannelBinding(
+                InetAddress.getByName("client.rabbit.hole"),
+                InetAddress.getByName("host.rabbit.hole"),
+                new byte[0]
+                ));
+        s.startAsServer(GSSUtil.GSS_KRB5_MECH_OID);
+        s.x().setChannelBinding(new ChannelBinding(
+                InetAddress.getByName("client.rabbit.hole"),
+                InetAddress.getByName("host.rabbit.hole"),
+                new byte[0]
+                ));
+        Context.handshake(c, s);
+
+        // Both req, NOT match
+        c.startAsClient(OneKDC.SERVER, GSSUtil.GSS_KRB5_MECH_OID);
+        c.x().setChannelBinding(new ChannelBinding(
+                InetAddress.getByName("client.rabbit.hole"),
+                InetAddress.getByName("host.rabbit.hole"),
+                new byte[0]
+                ));
+        s.startAsServer(GSSUtil.GSS_KRB5_MECH_OID);
+        s.x().setChannelBinding(new ChannelBinding(
+                InetAddress.getByName("client.rabbit.hole"),
+                InetAddress.getByName("host.rabbit.hole"),
+                new byte[1]     // 0 -> 1
+                ));
+        try {
+            Context.handshake(c, s);
+            throw new Exception("Acceptor should reject initiator");
+        } catch (GSSException ge) {
+            // Expected bahavior
+        }
+
+        // Acceptor req, reject
+        c.startAsClient(OneKDC.SERVER, GSSUtil.GSS_KRB5_MECH_OID);
+        s.startAsServer(GSSUtil.GSS_KRB5_MECH_OID);
+        s.x().setChannelBinding(new ChannelBinding(
+                InetAddress.getByName("client.rabbit.hole"),
+                InetAddress.getByName("host.rabbit.hole"),
+                new byte[0]
+                ));
+        try {
+            Context.handshake(c, s);
+            throw new Exception("Acceptor should reject initiator");
+        } catch (GSSException ge) {
+            // Expected bahavior
+            if (ge.getMajor() != GSSException.BAD_BINDINGS) {
+                throw ge;
+            }
+        }
+    }
+}