| /* |
| * 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.jackrabbit.webdav.util; |
| |
| import org.apache.jackrabbit.webdav.DavMethods; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import javax.servlet.http.HttpServletRequest; |
| import java.net.MalformedURLException; |
| import java.net.URL; |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Set; |
| |
| /** |
| * <code>CSRFUtil</code>... |
| */ |
| public class CSRFUtil { |
| |
| /** |
| * Constant used to |
| */ |
| public static final String DISABLED = "disabled"; |
| |
| /** |
| * Request content types for CSRF checking, see JCR-3909 |
| */ |
| public static final Set<String> CONTENT_TYPES = Collections.unmodifiableSet(new HashSet<String>( |
| Arrays.asList( |
| new String[] { |
| "application/x-www-form-urlencoded", |
| "multipart/form-data", |
| "text/plain", |
| null // no content type included in request |
| } |
| ) |
| )); |
| |
| /** |
| * logger instance |
| */ |
| private static final Logger log = LoggerFactory.getLogger(CSRFUtil.class); |
| |
| /** |
| * Disable referrer based CSRF protection |
| */ |
| private final boolean disabled; |
| |
| /** |
| * Additional allowed referrer hosts for CSRF protection |
| */ |
| private final Set<String> allowedReferrerHosts; |
| |
| /** |
| * Creates a new instance from the specified configuration, which defines |
| * the behaviour of the referrer based CSRF protection as follows: |
| * <ol> |
| * <li>If config is <code>null</code> or empty string the default |
| * behaviour is to allow only requests with an empty referrer header or a |
| * referrer host equal to the server host</li> |
| * <li>A comma separated list of additional allowed referrer hosts which are |
| * valid in addition to default behaviour (see above).</li> |
| * <li>The value {@link #DISABLED} may be used to disable the referrer checking altogether</li> |
| * </ol> |
| * |
| * @param config The configuration value which may be any of the following: |
| * <ul> |
| * <li><code>null</code> or empty string for the default behaviour, which |
| * only allows requests with an empty referrer header or a |
| * referrer host equal to the server host</li> |
| * <li>A comma separated list of additional allowed referrer hosts which are |
| * valid in addition to default behaviour (see above).</li> |
| * <li>{@link #DISABLED} in order to disable the referrer checking altogether</li> |
| * </ul> |
| */ |
| public CSRFUtil(String config) { |
| if (config == null || config.length() == 0) { |
| disabled = false; |
| allowedReferrerHosts = Collections.emptySet(); |
| } else { |
| if (DISABLED.equalsIgnoreCase(config.trim())) { |
| disabled = true; |
| allowedReferrerHosts = Collections.emptySet(); |
| } else { |
| disabled = false; |
| String[] allowed = config.split(","); |
| allowedReferrerHosts = new HashSet<String>(allowed.length); |
| for (String entry : allowed) { |
| allowedReferrerHosts.add(entry.trim()); |
| } |
| } |
| } |
| } |
| |
| public boolean isValidRequest(HttpServletRequest request) throws MalformedURLException { |
| int methodCode = DavMethods.getMethodCode(request.getMethod()); |
| if (disabled || DavMethods.DAV_POST != methodCode || !CONTENT_TYPES.contains(request.getContentType())) { |
| return true; |
| } else { |
| |
| String refHeader = request.getHeader("Referer"); |
| // empty referrer headers are not allowed for POST + relevant content types (see JCR-3909) |
| if (refHeader == null) { |
| return false; |
| } |
| |
| String host = new URL(refHeader).getHost(); |
| // test referrer-host equals server or |
| // if it is contained in the set of explicitly allowed host names |
| return host.equals(request.getServerName()) || allowedReferrerHosts.contains(host); |
| } |
| } |
| } |