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package com.key.common.plugs.xss;

import com.blogspot.radialmind.html.HTMLParser;
import com.blogspot.radialmind.xss.XSSFilter;

import java.io.StringReader;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.regex.Pattern;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/**
 * XSS保护
 *
 * @author storezhang
 */
public class XssHttpWrapper extends HttpServletRequestWrapper {

    private HttpServletRequest orgRequest;

    public XssHttpWrapper(HttpServletRequest request) {
        super(request);
        orgRequest = request;
    }

    /**
     * 覆盖getParameter方法，将参数名和参数值都做xss过滤。<br/>
     * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/>
     * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖
     */
    @Override
    public String getParameter(String name) {
        String value = super.getParameter(xssEncode(name));
        if (value != null) {
            value = xssEncode(value);
        }
        return value;
    }
    
    /**
     * 覆盖getHeader方法，将参数名和参数值都做xss过滤。<br/>
     * 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/> getHeaderNames 也可能需要覆盖
     */
    @Override
    public String getHeader(String name) {
        String value = super.getHeader(xssEncode(name));
        if (value != null) {
            value = xssEncode(value);
        }
        return value;
    }

    
    
    /**
    *
    * @param name
    * @return
    */
   public String[] getParameterValues(String name) {
       String[] values = super.getParameterValues(name);
       if (values != null) {
           for (int i = 0; i < values.length; i++) {
               values[i] = xssEncode(values[i]);
           }
       }
       return values;
   }

   /**
    * @return
    */
   public Map getParameterMap() {

       HashMap paramMap = (HashMap) super.getParameterMap();
       paramMap = (HashMap) paramMap.clone();

       for (Iterator iterator = paramMap.entrySet().iterator(); iterator.hasNext(); ) {
           Map.Entry entry = (Map.Entry) iterator.next();
           String[] values = (String[]) entry.getValue();
           for (int i = 0; i < values.length; i++) {
               if(values[i] instanceof String){
                   values[i] = xssEncode((String)values[i]);
               }
           }
           entry.setValue(values);
       }
       return paramMap;
   }
    


    /**
     * 获取最原始的request
     *
     * @return
     */
    public HttpServletRequest getOrgRequest() {
        return orgRequest;
    }

    /**
     * 获取最原始的request的静态方法
     *
     * @return
     */
    public static HttpServletRequest getOrgRequest(HttpServletRequest req) {
        if (req instanceof XssHttpWrapper) {
            return ((XssHttpWrapper) req).getOrgRequest();
        }
        return req;
    }



    public String escape(String s)
    {
        StringBuilder sb = new StringBuilder(s.length() + 16);
        for (int i = 0; i < s.length(); i++)
        {
            char c = s.charAt(i);
            switch (c)
            {
                case '>':
                    sb.append('＞');// 全角大于号
                    break;
                case '<':
                    sb.append('＜');// 全角小于号
                    break;
                case '\'':
                    sb.append('‘');// 全角单引号
                    break;
                case '\"':
                    sb.append('“');// 全角双引号
                    break;
                case '\\':
                    sb.append('＼');// 全角斜线
                    break;
                case '%':
                    sb.append('％'); // 全角冒号
                    break;
                default:
                    sb.append(c);
                    break;
            }

        }
        return sb.toString();
    }


    /**
     * 将容易引起xss漏洞的半角字符直接替换成全角字符
     *
     * @param s
     * @return
     */
   /* private static String xssEncode(String s) {
        if (s == null || s.isEmpty()) {
            return s;
        }

        StringReader reader = new StringReader(s);
        StringWriter writer = new StringWriter();
        try {
            HTMLParser.process(reader, writer, new XSSFilter(), true);
            return writer.toString();
        } catch (NullPointerException e) {
            return s;
        } catch (Exception ex) {
            ex.printStackTrace(System.out);
        }
        return null;
    }
    */

    /**
     * 将容易引起xss漏洞的半角字符直接替换成全角字符
     *
     * @param s
     * @return
     */
    public String xssEncode(String s)
    {
        if (s == null || s.isEmpty())
        {
            return s;
        }

        String result = stripXSS(s);
        if (null != result)
        {
            result = escape(result);
        }

        return result;
    }

    /**
     * 处理插件之所以报 mismatched tree node: EOF expecting错误是因为其对注入的脚本格式有校验
     * 比如注入<scirpt>而没有匹配的结束标签</scirpt>时会报该错误，注入代码中开始标签和结束标签不匹配时会出该问题
     * @param value
     * @return
     */
    private String stripXSS(String value)
    {
        if (value != null)
        {
            // NOTE: It's highly recommended to use the ESAPI library and uncomment the following line to
            // avoid encoded attacks.
            // value = ESAPI.encoder().canonicalize(value);
            // Avoid null characters
            value = value.replaceAll("", "");
            // Avoid anything between script tags
            Pattern scriptPattern = Pattern.compile("<script>(.*?)</script>", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");
            // Avoid anything in a src='...' type of expression
            scriptPattern = Pattern.compile("src[\r\n]*=[\r\n]*\\\'(.*?)\\\'", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
            scriptPattern = Pattern.compile("src[\r\n]*=[\r\n]*\\\"(.*?)\\\"", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
            // Remove any lonesome </script> tag
            scriptPattern = Pattern.compile("</script>", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");
            // Remove any lonesome <script ...> tag
            scriptPattern = Pattern.compile("<script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
            // Avoid eval(...) expressions
            scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
            // Avoid expression(...) expressions
            scriptPattern = Pattern.compile("expression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
            // Avoid javascript:... expressions
            scriptPattern = Pattern.compile("javascript:", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");
            // Avoid vbscript:... expressions
            scriptPattern = Pattern.compile("vbscript:", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");
            // Avoid onload= expressions
            scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");

            scriptPattern = Pattern.compile("<iframe>(.*?)</iframe>", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");

            scriptPattern = Pattern.compile("</iframe>", Pattern.CASE_INSENSITIVE);
            value = scriptPattern.matcher(value).replaceAll("");
            // Remove any lonesome <script ...> tag
            scriptPattern = Pattern.compile("<iframe(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);
            value = scriptPattern.matcher(value).replaceAll("");
        }
        return value;
    }
}