[GitHub] [activemq-artemis] gtully commented on a change in pull request #3470: ARTEMIS-3106 - Support for SASL-SCRAM

[GitBox <gi...@apache.org>]

gtully commented on a change in pull request #3470:
URL: https://github.com/apache/activemq-artemis/pull/3470#discussion_r596931243



##########
File path: artemis-protocols/artemis-amqp-protocol/src/main/java/org/apache/activemq/artemis/protocol/amqp/sasl/scram/SCRAMServerSASLFactory.java
##########
@@ -0,0 +1,241 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.activemq.artemis.protocol.amqp.sasl.scram;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.security.GeneralSecurityException;
+import java.security.NoSuchAlgorithmException;
+import java.security.Principal;
+import java.util.Iterator;
+import java.util.UUID;
+
+import javax.security.auth.Subject;
+import javax.security.auth.callback.Callback;
+import javax.security.auth.callback.CallbackHandler;
+import javax.security.auth.callback.NameCallback;
+import javax.security.auth.callback.UnsupportedCallbackException;
+import javax.security.auth.login.LoginContext;
+
+import org.apache.activemq.artemis.core.server.ActiveMQServer;
+import org.apache.activemq.artemis.protocol.amqp.broker.AmqpInterceptor;
+import org.apache.activemq.artemis.protocol.amqp.broker.ProtonProtocolManager;
+import org.apache.activemq.artemis.protocol.amqp.sasl.SASLResult;
+import org.apache.activemq.artemis.protocol.amqp.sasl.ServerSASL;
+import org.apache.activemq.artemis.protocol.amqp.sasl.ServerSASLFactory;
+import org.apache.activemq.artemis.spi.core.protocol.ProtocolManager;
+import org.apache.activemq.artemis.spi.core.protocol.RemotingConnection;
+import org.apache.activemq.artemis.spi.core.remoting.Connection;
+import org.apache.activemq.artemis.spi.core.security.jaas.DigestCallback;
+import org.apache.activemq.artemis.spi.core.security.jaas.HmacCallback;
+import org.apache.activemq.artemis.spi.core.security.jaas.SCRAMMechanismCallback;
+import org.apache.activemq.artemis.spi.core.security.scram.SCRAM;
+import org.apache.activemq.artemis.spi.core.security.scram.ScramException;
+import org.apache.activemq.artemis.spi.core.security.scram.UserData;
+import org.jboss.logging.Logger;
+
+/**
+ * abstract class that implements the SASL-SCRAM authentication scheme, concrete implementations
+ * must supply the {@link SCRAM} type to use and be register via SPI
+ */
+public abstract class SCRAMServerSASLFactory implements ServerSASLFactory {
+
+   private final Logger logger = Logger.getLogger(getClass());
+   private final SCRAM scramType;
+
+   public SCRAMServerSASLFactory(SCRAM scram) {
+      this.scramType = scram;
+   }
+
+   @Override
+   public String getMechanism() {
+      return scramType.getName();
+   }
+
+   @Override
+   public boolean isDefaultPermitted() {
+      return false;
+   }
+
+   @Override
+   public ServerSASL create(ActiveMQServer server, ProtocolManager<AmqpInterceptor> manager, Connection connection,
+                            RemotingConnection remotingConnection) {
+      try {
+         if (manager instanceof ProtonProtocolManager) {
+            ScramServerFunctionalityImpl scram =
+                     new ScramServerFunctionalityImpl(scramType.getDigest(), scramType.getHmac(),
+                                                      UUID.randomUUID().toString());
+            String loginConfigScope = ((ProtonProtocolManager) manager).getSaslLoginConfigScope();
+            return new SCRAMServerSASL(scramType.getName(), scram, loginConfigScope, logger);
+         }
+      } catch (NoSuchAlgorithmException e) {
+         // can't be used then...
+      }
+      return null;
+   }
+
+   private static final class SCRAMServerSASL implements ServerSASL {
+
+      private final String name;
+      private final ScramServerFunctionality scram;
+      private SASLResult result;
+      private final String loginConfigScope;
+      private final Logger logger;
+
+      SCRAMServerSASL(String name, ScramServerFunctionality scram, String loginConfigScope, Logger logger) {
+         this.name = name;
+         this.scram = scram;
+         this.loginConfigScope = loginConfigScope;
+         this.logger = logger;
+      }
+
+      @Override
+      public String getName() {
+         return name;
+      }
+
+      @Override
+      public byte[] processSASL(byte[] bytes) {
+         String message = new String(bytes, StandardCharsets.US_ASCII);
+         try {
+            switch (scram.getState()) {
+               case INITIAL: {
+                  String userName = scram.handleClientFirstMessage(message);
+                  if (userName != null) {
+
+                     LoginContext loginContext = new LoginContext(loginConfigScope, new CallbackHandler() {
+
+                        @Override
+                        public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException {
+                           for (Callback callback : callbacks) {
+                              if (callback instanceof NameCallback) {
+                                 ((NameCallback) callback).setName(userName);
+                              } else if (callback instanceof SCRAMMechanismCallback) {
+                                 ((SCRAMMechanismCallback) callback).setMechanism(name);
+                              } else if (callback instanceof DigestCallback) {
+                                 ((DigestCallback) callback).setDigest(scram.getDigest());
+                              } else if (callback instanceof HmacCallback) {
+                                 ((HmacCallback) callback).setHmac(scram.getHmac());
+                              } else {
+                                 throw new UnsupportedCallbackException(callback, "Unrecognized Callback " +
+                                          callback.getClass().getSimpleName());
+                              }
+                           }
+                        }
+                     });
+                     loginContext.login();

Review comment:
       Christoph, this login call has me wondering.... here we have a successfully authenticated subject from a JAAS perspective but have not yet completed the SASL exchange. Could this be a problem? If there are any other login modules in that realm the semantics may be broken a little.
   When I thought of doing something similar, I imagined the callback handlers would provide the mechanism to perform challenge/response - ie: it would all happen as part of the login call. Either through a fancy handler that would expose the state machine or some series/chain of handlers that represent the state transitions.
   I would need to do a little proof of concept to verify that would work... but is that something you considered?
   I am not certain that the current use of login it is a problem, but it does seem odd.




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