| /* |
| * 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.hadoop.chukwa.util; |
| |
| import javax.servlet.http.HttpServletRequest; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import org.jsoup.Jsoup; |
| import org.jsoup.safety.Whitelist; |
| import org.owasp.esapi.ESAPI; |
| |
| public class XssFilter { |
| private HttpServletRequest request = null; |
| private static Log LOG = LogFactory.getLog(XssFilter.class); |
| |
| public XssFilter() { |
| } |
| |
| public XssFilter(HttpServletRequest request) { |
| // Return the cleansed request |
| this.request = request; |
| } |
| |
| public String getParameter(String key) { |
| String value=null; |
| try { |
| value=filter(this.request.getParameter(key)); |
| } catch (Exception e) { |
| LOG.info("XssFilter.getParameter: Cannot get parameter for: "+key); |
| } |
| return value; |
| } |
| |
| public String[] getParameterValues(String key) { |
| String[] values=null; |
| try { |
| values = this.request.getParameterValues(key); |
| int i = 0; |
| for(String value : values) { |
| values[i] = filter(value); |
| i++; |
| } |
| } catch (Exception e) { |
| LOG.info("XssFilter.getParameterValues: cannot get parameter for: "+key); |
| } |
| return values; |
| } |
| |
| /** |
| * Strips any potential XSS threats out of the value |
| * @param value is a string |
| * @return filtered string |
| */ |
| public String filter( String value ) { |
| if( value == null ) |
| return null; |
| |
| // Use the ESAPI library to avoid encoded attacks. |
| value = ESAPI.encoder().canonicalize( value ); |
| |
| // Avoid null characters |
| value = value.replaceAll("\0", ""); |
| |
| // Clean out HTML |
| value = Jsoup.clean( value, Whitelist.none() ); |
| |
| return value; |
| } |
| } |