content: /*
   * 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.kafka.common.security.scram.internals;
  
  
  import org.apache.kafka.common.errors.SaslAuthenticationException;
  import org.apache.kafka.common.security.authenticator.CredentialCache;
  import org.apache.kafka.common.security.scram.ScramCredential;
  import org.apache.kafka.common.security.scram.internals.ScramMessages.ClientFirstMessage;
  import org.apache.kafka.common.security.scram.internals.ScramMessages.ServerFinalMessage;
  import org.apache.kafka.common.security.scram.internals.ScramMessages.ServerFirstMessage;
  import org.apache.kafka.common.security.token.delegation.internals.DelegationTokenCache;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  import org.mockito.Mockito;
  
  import java.nio.charset.StandardCharsets;
  import java.util.Base64;
  import java.util.HashMap;
  
  import javax.security.sasl.SaslException;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  public class ScramSaslServerTest {
  
      private static final String USER_A = "userA";
      private static final String USER_B = "userB";
  
      private ScramFormatter formatter;
      private ScramSaslServer saslServer;
  
      @BeforeEach
      public void setUp() throws Exception {
          ScramMechanism mechanism = ScramMechanism.SCRAM_SHA_256;
          formatter  = new ScramFormatter(mechanism);
          CredentialCache.Cache<ScramCredential> credentialCache = new CredentialCache().createCache(mechanism.mechanismName(), ScramCredential.class);
          credentialCache.put(USER_A, formatter.generateCredential("passwordA", 4096));
          credentialCache.put(USER_B, formatter.generateCredential("passwordB", 4096));
          ScramServerCallbackHandler callbackHandler = new ScramServerCallbackHandler(credentialCache, new DelegationTokenCache(ScramMechanism.mechanismNames()));
          saslServer = new ScramSaslServer(mechanism, new HashMap<>(), callbackHandler);
      }
  
      @Test
      public void noAuthorizationIdSpecified() throws Exception {
          byte[] nextChallenge = saslServer.evaluateResponse(clientFirstMessage(USER_A, null));
          assertTrue(nextChallenge.length > 0, "Next challenge is empty");
      }
  
      @Test
      public void authorizationIdEqualsAuthenticationId() throws Exception {
          byte[] nextChallenge = saslServer.evaluateResponse(clientFirstMessage(USER_A, USER_A));
          assertTrue(nextChallenge.length > 0, "Next challenge is empty");
      }
  
      @Test
      public void authorizationIdNotEqualsAuthenticationId() {
          assertThrows(SaslAuthenticationException.class, () -> saslServer.evaluateResponse(clientFirstMessage(USER_A, USER_B)));
      }
  
      /**
       * Validate that server responds with client's nonce as prefix of its nonce in the
       * server first message.
       * <br>
       * In addition, it checks that the client final message has nonce that it sent in its
       * first message.
       */
      @Test
      public void validateNonceExchange() throws SaslException {
          ScramSaslServer spySaslServer = Mockito.spy(saslServer);
          byte[] clientFirstMsgBytes = clientFirstMessage(USER_A, USER_A);
          ClientFirstMessage clientFirstMessage = new ClientFirstMessage(clientFirstMsgBytes);
  
          byte[] serverFirstMsgBytes = spySaslServer.evaluateResponse(clientFirstMsgBytes);
          ServerFirstMessage serverFirstMessage = new ServerFirstMessage(serverFirstMsgBytes);
          assertTrue(serverFirstMessage.nonce().startsWith(clientFirstMessage.nonce()),
              "Nonce in server message should start with client first message's nonce");
  
          byte[] clientFinalMessage = clientFinalMessage(serverFirstMessage.nonce());
          Mockito.doNothing()
              .when(spySaslServer).verifyClientProof(Mockito.any(ScramMessages.ClientFinalMessage.class));
          byte[] serverFinalMsgBytes = spySaslServer.evaluateResponse(clientFinalMessage);
          ServerFinalMessage serverFinalMessage = new ServerFinalMessage(serverFinalMsgBytes);
          assertNull(serverFinalMessage.error(), "Server final message should not contain error");
      }
  
      @Test
      public void validateFailedNonceExchange() throws SaslException {
          ScramSaslServer spySaslServer = Mockito.spy(saslServer);
          byte[] clientFirstMsgBytes = clientFirstMessage(USER_A, USER_A);
          ClientFirstMessage clientFirstMessage = new ClientFirstMessage(clientFirstMsgBytes);
  
          byte[] serverFirstMsgBytes = spySaslServer.evaluateResponse(clientFirstMsgBytes);
          ServerFirstMessage serverFirstMessage = new ServerFirstMessage(serverFirstMsgBytes);
          assertTrue(serverFirstMessage.nonce().startsWith(clientFirstMessage.nonce()),
              "Nonce in server message should start with client first message's nonce");
  
          byte[] clientFinalMessage = clientFinalMessage(formatter.secureRandomString());
          Mockito.doNothing()
              .when(spySaslServer).verifyClientProof(Mockito.any(ScramMessages.ClientFinalMessage.class));
          SaslException saslException = assertThrows(SaslException.class,
              () -> spySaslServer.evaluateResponse(clientFinalMessage));
          assertEquals("Invalid client nonce in the final client message.",
              saslException.getMessage(),
              "Failure message: " + saslException.getMessage());
      }
  
      @Test
      public void validateFailedNonceExchangeWithPrependingClientNonce() throws SaslException {
          ScramSaslServer spySaslServer = Mockito.spy(saslServer);
          byte[] clientFirstMsgBytes = clientFirstMessage(USER_A, USER_A);
          ClientFirstMessage clientFirstMessage = new ClientFirstMessage(clientFirstMsgBytes);
  
          byte[] serverFirstMsgBytes = spySaslServer.evaluateResponse(clientFirstMsgBytes);
          ServerFirstMessage serverFirstMessage = new ServerFirstMessage(serverFirstMsgBytes);
          assertTrue(serverFirstMessage.nonce().startsWith(clientFirstMessage.nonce()),
                  "Nonce in server message should start with client first message's nonce");
  
          //send client final message with nonce prepended with clientFirstMessage's nonce
          byte[] clientFinalMessage = clientFinalMessage(clientFirstMessage.nonce() + serverFirstMessage.nonce());
          Mockito.doNothing()
                  .when(spySaslServer).verifyClientProof(Mockito.any(ScramMessages.ClientFinalMessage.class));
          SaslException saslException = assertThrows(SaslException.class,
                  () -> spySaslServer.evaluateResponse(clientFinalMessage));
          assertEquals("Invalid client nonce in the final client message.",
                  saslException.getMessage(),
                  "Failure message: " + saslException.getMessage());
      }
  
      private byte[] clientFirstMessage(String userName, String authorizationId) {
          String nonce = formatter.secureRandomString();
          String authorizationField = authorizationId != null ? "a=" + authorizationId : "";
          String firstMessage = String.format("n,%s,n=%s,r=%s", authorizationField, userName, nonce);
          return firstMessage.getBytes(StandardCharsets.UTF_8);
      }
  
      private byte[] clientFinalMessage(String nonce) {
          String channelBinding = randomBytesAsString();
          String proof = randomBytesAsString();
  
          String message = String.format("c=%s,r=%s,p=%s", channelBinding, nonce, proof);
          return message.getBytes(StandardCharsets.UTF_8);
      }
  
      private String randomBytesAsString() {
          return Base64.getEncoder().encodeToString(formatter.secureRandomBytes());
      }
  }
  