Mercurial > hg > LightPIT / file revision

 /*

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

  * 

  * Copyright 2017 Mike Becker. All rights reserved.

  * 

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   1. Redistributions of source code must retain the above copyright

  *      notice, this list of conditions and the following disclaimer.

  *

  *   2. Redistributions in binary form must reproduce the above copyright

  *      notice, this list of conditions and the following disclaimer in the

  *      documentation and/or other materials provided with the distribution.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  * 

  */

 package de.uapcore.lightpit;

 import java.sql.Connection;

 import java.sql.DatabaseMetaData;

 import java.sql.SQLException;

 import java.util.Optional;

 import javax.naming.Context;

 import javax.naming.InitialContext;

 import javax.naming.NamingException;

 import javax.servlet.ServletContext;

 import javax.servlet.ServletContextEvent;

 import javax.servlet.ServletContextListener;

 import javax.servlet.annotation.WebListener;

 import javax.sql.DataSource;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * Provides access to different privilege layers within the database.

  */

 @WebListener

 public final class DatabaseFacade implements ServletContextListener {

     private static final Logger LOG = LoggerFactory.getLogger(DatabaseFacade.class);

     /**

      * Timeout in seconds for the validation test.

      */

     private static final int DB_TEST_TIMEOUT = 10;

     /**

      * The default schema to test against when validating the connection.

      * 

      * May be overridden by context parameter.

      */

     private static final String DB_DEFAULT_SCHEMA = "lightpit";

     /**

      * The attribute name in the servlet context under which an instance of this class can be found.

      */

     public static final String SC_ATTR_NAME = DatabaseFacade.class.getName();

     private ServletContext sc;

     private static final String PRIVILEGED_DS_JNDI_NAME = "jdbc/lightpit/dbo";

     private Optional<DataSource> privilegedDataSource;

     private static final String UNPRIVILEGED_DS_JNDI_NAME = "jdbc/lightpit/app";

     private Optional<DataSource> unprivilegedDataSource;

     /**

      * Returns an optional privileged data source.

      * 

      * Privileged data sources should be able to execute any kind of DDL

      * statements to perform installation or configuration steps.

      * 

      * This optional should always be empty in live operation. Modules which

      * provide installation or configuration steps MUST check the presence of

      * a privileged data source and SHOULD display an informative message if

      * it is currently disabled.

      * 

      * @return an optional privileged data source

      */

     public Optional<DataSource> getPrivilegedDataSource() {

         return privilegedDataSource;

     }

     /**

      * Returns an optional unprivileged data source.

      * 

      * The Optional returned should never be empty. However, if something goes

      * wrong during initialization, the data source might be absent.

      * Hence, users of this data source are forced to check the existence.

      * 

      * @return an optional unprivileged data source

      */

     public Optional<DataSource> getUnprivilegedDataSource() {

         return unprivilegedDataSource;

     }

     /**

      * Returns the JNDI resource name of the privileged data source.

      * 

      * Modules may use this information to provide useful information to the user.

      * 

      * @return the JNDI resource name of the privileged data source

      */

     public String getPrivilegedDataSourceJNDIName() {

         return PRIVILEGED_DS_JNDI_NAME;

     }

     /**

      * Returns the JNDI resource name of the unprivileged data source.

      * 

      * Modules may use this information to provide useful information to the user.

      * 

      * @return the JNDI resource name of the unprivileged data source

      */

     public String getUnprivilegedDataSourceJNDIName() {

         return UNPRIVILEGED_DS_JNDI_NAME;

     }

     private static void checkConnection(DataSource ds, String testSchema, String errMsg) {

         try (Connection conn = ds.getConnection()) {

             if (!conn.isValid(DB_TEST_TIMEOUT)) {

                 throw new SQLException("Validation check failed.");

             }

             if (conn.isReadOnly()) {

                 throw new SQLException("Connection is read-only and thus unusable.");

             }

             if (!conn.getSchema().equals(testSchema)) {

                 throw new SQLException(String.format("Connection is not configured to use the schema %s.", testSchema));

             }

             DatabaseMetaData metaData = conn.getMetaData();

             LOG.info("Connections as {} to {}/{} ready to go.", metaData.getUserName(), metaData.getURL(), conn.getSchema());

         } catch (SQLException ex) {

             LOG.error(errMsg, ex);

         }

     }

     private static Optional<DataSource> retrievePrivilegedDataSource(Context ctx) {

         DataSource ret = null;

         try {

             ret = (DataSource)ctx.lookup(PRIVILEGED_DS_JNDI_NAME);

             LOG.info("Privileged data source {} retrieved from context.", PRIVILEGED_DS_JNDI_NAME);

             LOG.warn("Your application may be vulnerable due to privileged database access. Make sure that privileged data sources are only available during installation or configuration.");

         } catch (NamingException ex) {

             LOG.info("Privileged data source not available. This is perfectly OK. Activate only, if you need to do installation or configuration.");

             /* in case the absence of the DataSource is not intended, log something more useful on debug level */

             LOG.debug("Reason for the missing data source: ", ex);

         }

         return Optional.ofNullable(ret);

     }

     private static Optional<DataSource> retrieveUnprivilegedDataSource(Context ctx) {

         DataSource ret = null;

         try {

             ret = (DataSource)ctx.lookup(UNPRIVILEGED_DS_JNDI_NAME);

             LOG.info("Unprivileged data source retrieved.");

         } catch (NamingException ex) {

             LOG.error("Unprivileged data source {} not available.", UNPRIVILEGED_DS_JNDI_NAME);

             /* for the unprivileged DataSource log the exception on error level (ordinary admins could find this useful) */

             LOG.error("Reason for the missing data source: ", ex);

         }

         return Optional.ofNullable(ret);

     }

     @Override

     public void contextInitialized(ServletContextEvent sce) {

         sc = sce.getServletContext();

         privilegedDataSource = unprivilegedDataSource = null;

         final String contextName = Optional

                 .ofNullable(sc.getInitParameter(Constants.CTX_ATTR_JNDI_CONTEXT))

                 .orElse("java:comp/env");

         final String dbSchema = Optional

                 .ofNullable(sc.getInitParameter(Constants.CTX_ATTR_DB_SCHEMA))

                 .orElse(DB_DEFAULT_SCHEMA);

         try {

             LOG.debug("Trying to access JNDI context {}...", contextName);

             Context initialCtx = new InitialContext();

             Context ctx = (Context) initialCtx.lookup(contextName);

             privilegedDataSource = retrievePrivilegedDataSource(ctx);

             unprivilegedDataSource = retrieveUnprivilegedDataSource(ctx);

             privilegedDataSource.ifPresent((ds) -> checkConnection(ds, dbSchema, "Checking privileged connection failed"));

             unprivilegedDataSource.ifPresent((ds) -> checkConnection(ds, dbSchema, "Checking unprivileged connection failed"));

         } catch (NamingException | ClassCastException ex) {

             LOG.error("Cannot access JNDI resources.", ex);

         }

         sc.setAttribute(SC_ATTR_NAME, this);

         LOG.info("Database facade injected into ServletContext.");

     }

     @Override

     public void contextDestroyed(ServletContextEvent sce) {

         privilegedDataSource = unprivilegedDataSource = null;

     }    

 }