001/*
002 * Copyright 2025 The Apache Software Foundation.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.apache.wiki.http.filter;
017
018import jakarta.servlet.Filter;
019import jakarta.servlet.FilterChain;
020import jakarta.servlet.FilterConfig;
021import jakarta.servlet.ServletException;
022import jakarta.servlet.ServletRequest;
023import jakarta.servlet.ServletResponse;
024import org.apache.wiki.util.HttpUtil;
025
026import java.io.IOException;
027
028
029/**
030 * Content-Security-Policy (CSP): Mitigates XSS and other injection attacks by
031 * defining approved sources of content that the browser can load.
032 */
033public class CSPFilter implements Filter {
034
035    private String mode = "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self'; img-src 'self';";
036
037    /** {@inheritDoc} */
038    @Override
039    public void init( final FilterConfig filterConfig ) {
040        final String configMode = FilterOperations.initValue( filterConfig, "CSPValue", "csp.value" );
041        if( configMode != null ) {
042            mode = configMode;
043        }
044    }
045
046    /** {@inheritDoc} */
047    @Override
048    public void doFilter( final ServletRequest request, final ServletResponse response, final FilterChain chain ) throws IOException, ServletException {
049        HttpUtil.addHeader( response,"Content-Security-Policy", mode );
050        chain.doFilter( request, response );
051    }
052
053}