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.cassandra.auth;
  
  import java.security.cert.Certificate;
  
  import org.apache.cassandra.exceptions.AuthenticationException;
  
  /**
   * Interface for certificate validation and authorization for mTLS authenticators.
   * <p>
   * This interface can be implemented to provide logic for extracting custom identities from client certificates
   * to uniquely identify the certificates. It can also be used to provide custom authorization logic to authenticate
   * clients using client certificates during mTLS connections.
   */
  public interface MutualTlsCertificateValidator
  {
      /**
       * Perform any checks that are to be performed on the certificate before making authorization check to grant the
       * access to the client during mTLS connection.
       *
       * <p>For example:
       * <ul>
       *  <li>Verifying CA information
       *  <li>Checking CN information
       *  <li>Validating Issuer information
       *  <li>Checking organization information etc
       * </ul>
       *
       * @param clientCertificateChain client certificate chain
       * @return {@code true} if the certificate is valid, {@code false} otherwise
       */
      boolean isValidCertificate(Certificate[] clientCertificateChain);
  
      /**
       * This method should provide logic to extract identity out of a certificate to perform mTLS authentication.
       *
       * <p>An example of identity could be the following:
       * <ul>
       *  <li>an identifier in SAN of the certificate like SPIFFE
       *  <li>CN of the certificate
       *  <li>any other fields in the certificate can be combined and be used as identifier of the certificate
       * </ul>
       *
       * @param clientCertificateChain client certificate chain
       * @return identifier extracted from certificate
       * @throws AuthenticationException when identity cannot be extracted
       */
      String identity(Certificate[] clientCertificateChain) throws AuthenticationException;
  }
  