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.ambari.server.security.encryption;
  
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.util.Random;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.ambari.server.AmbariException;
  import org.apache.ambari.server.configuration.Configuration;
  import org.apache.ambari.server.security.credential.Credential;
  import org.apache.ambari.server.security.credential.GenericKeyCredential;
  import org.apache.ambari.server.utils.Closeables;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class CredentialProvider {
    public static final Pattern PASSWORD_ALIAS_PATTERN = Pattern.compile("\\$\\{alias=[\\w\\.]+\\}");
  
    protected char[] chars = {'a', 'b', 'c', 'd', 'e', 'f', 'g',
        'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
        'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K',
        'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
        '2', '3', '4', '5', '6', '7', '8', '9'};
  
    private CredentialStore keystoreService;
    private static final Logger LOG = LoggerFactory.getLogger(CredentialProvider.class);
  
    public CredentialProvider(String masterKey, Configuration configuration) throws AmbariException {
      MasterKeyService masterKeyService;
      if (masterKey != null) {
        masterKeyService = new MasterKeyServiceImpl(masterKey);
      } else {
        masterKeyService = new MasterKeyServiceImpl(configuration);
      }
      if (!masterKeyService.isMasterKeyInitialized()) {
        throw new AmbariException("Master key initialization failed.");
      }
      this.keystoreService = new FileBasedCredentialStore(configuration.getMasterKeyStoreLocation());
      this.keystoreService.setMasterKeyService(masterKeyService);
    }
  
    public char[] getPasswordForAlias(String alias) throws AmbariException {
      Credential credential = (isAliasString(alias))
          ? keystoreService.getCredential(getAliasFromString(alias))
          : keystoreService.getCredential(alias);
  
      return (credential instanceof GenericKeyCredential)
          ? ((GenericKeyCredential) credential).getKey()
          : null;
    }
  
    public void generateAliasWithPassword(String alias) throws AmbariException {
      String passwordString = generatePassword(16);
      addAliasToCredentialStore(alias, passwordString);
    }
  
    public void addAliasToCredentialStore(String alias, String passwordString)
        throws AmbariException {
      if (alias == null || alias.isEmpty()) {
        throw new IllegalArgumentException("Alias cannot be null or empty.");
      }
      if (passwordString == null || passwordString.isEmpty()) {
        throw new IllegalArgumentException("Empty or null password not allowed.");
      }
      keystoreService.addCredential(alias, new GenericKeyCredential(passwordString.toCharArray()));
    }
  
    private String generatePassword(int length) {
      StringBuilder sb = new StringBuilder();
      Random r = new Random();
      for (int i = 0; i < length; i++) {
        sb.append(chars[r.nextInt(chars.length)]);
      }
      return sb.toString();
    }
  
    public static boolean isAliasString(String aliasStr) {
      if (aliasStr == null || aliasStr.isEmpty()) {
        return false;
      }
      Matcher matcher = PASSWORD_ALIAS_PATTERN.matcher(aliasStr);
      return matcher.matches();
    }
  
    private String getAliasFromString(String strPasswd) {
      return strPasswd.substring(strPasswd.indexOf("=") + 1, strPasswd.length() - 1);
    }
  
    protected CredentialStore getKeystoreService() {
      return keystoreService;
    }
  
    /**
     * Credential Store entry point
     * args[0] => Action (GET/PUT)
     * args[1] => Alias
     * args[2] => Payload (FilePath for GET/Password for PUT)
     * args[3] => Master Key (Empty)
     *
     * @param args
     */
    public static void main(String args[]) {
      if (args != null && args.length > 0) {
        String action = args[0];
        String alias = null;
        String masterKey = null;
        CredentialProvider credentialProvider = null;
        Configuration configuration = new Configuration();
        if (args.length > 1 && !args[1].isEmpty()) {
          alias = args[1];
        } else {
          LOG.error("No valid arguments provided.");
          System.exit(1);
        }
        // None - To avoid incorrectly assuming redirection as argument
        if (args.length > 3 && !args[3].isEmpty() && !args[3].equalsIgnoreCase("None")) {
          masterKey = args[3];
          LOG.debug("Master key provided as an argument.");
        }
        try {
          credentialProvider = new CredentialProvider(masterKey, configuration);
        } catch (Exception ex) {
          ex.printStackTrace();
          System.exit(1);
        }
        LOG.info("action => " + action + ", alias => " + alias);
        if (action.equalsIgnoreCase("PUT")) {
          String password = null;
          if (args.length > 2 && !args[2].isEmpty()) {
            password = args[2];
          }
          if (password != null && !password.isEmpty()) {
            try {
              credentialProvider.addAliasToCredentialStore(alias, password);
            } catch (AmbariException e) {
              e.printStackTrace();
            }
          } else {
            LOG.error("Alias and password are required arguments.");
            System.exit(1);
          }
        } else if (action.equalsIgnoreCase("GET")) {
          String writeFilePath = null;
          if (args.length > 2 && !args[2].isEmpty()) {
            writeFilePath = args[2];
          }
          if (writeFilePath != null && !writeFilePath.isEmpty()) {
            String passwd = "";
            try {
              char[] retPasswd = credentialProvider.getPasswordForAlias(alias);
              if (retPasswd != null) {
                passwd = new String(retPasswd);
              }
            } catch (AmbariException e) {
              LOG.error("Error retrieving password for alias.");
              e.printStackTrace();
            }
            FileOutputStream fo = null;
            try {
              fo = new FileOutputStream(writeFilePath);
              fo.write(passwd.getBytes());
            } catch (IOException e) {
              e.printStackTrace();
            } finally {
              Closeables.closeSilently(fo);
            }
          } else {
            LOG.error("Alias and file path are required arguments.");
          }
        }
      } else {
        LOG.error("No arguments provided to " + "CredentialProvider");
        System.exit(1);
      }
      System.exit(0);
    }
  }
  