一次诡异的关于filter的问题

摘要：接收前台请求封装的时，莫名传到后台就变成了。找了半天，一直以后是前台的问题，一直在翻阅各种代码。后来，请教大佬，大佬一听到刚好少了后，灵光乍现，感觉是拦截器的原因，后来查阅，果不其然。全称跨站脚本攻击，是程序中最常见的漏洞。

接收前台post请求封装的"versionDescription":"eeeeee",时，莫名传到后台就变成"versionDeion":"eeeeee",了。

找了半天，一直以后是前台的问题，一直在翻阅各种js代码。 后来，请教大佬，大佬一听到刚好少了script后，灵光乍现，感觉是拦截器的原因，后来查阅，果不其然。

XSS 全称(Cross Site Scripting) 跨站脚本攻击， 是Web程序中最常见的漏洞。指攻击者在网页中嵌入客户端脚本(例如JavaScript), 当用户浏览此网页时，脚本就会在用户的浏览器上执行，从而达到攻击者的目的. 比如获取用户的Cookie，导航到恶意网站,携带木马等

参考https://www.cnblogs.com/xuxiu...

参考 http://www.cnblogs.com/jiangs...

参考 https://blog.csdn.net/qq_3292...

参考 https://blog.csdn.net/u012114...

这是一个预防XSS注入的拦截器，web.xml配置如下：

    
        xssFilter
        com.cashew.utils.XssFilter
    
    
        xssFilter
        /*
    

拦截器：

package com.sgcc.utils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;

import org.apache.log4j.Logger;

public class XssFilter implements Filter {

    Logger log = Logger.getLogger(this.getClass());
    private static Pattern SCRIPT_PATTERN = Pattern
            .compile(".*");
    private static Pattern HTML_PATTERN = Pattern.compile("<[^>]+>");

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest servletRequest,
            ServletResponse servletResponse, FilterChain chain)
            throws IOException, ServletException {
        // 获得在下面代码中要用的request,response,session对象
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        // 设置cookie heetOnly
        Cookie[] cookies = request.getCookies();
        if (cookies != null && cookies.length > 0) {
            Cookie cookie = cookies[0];
            if (cookie != null) {
                // Servlet 2.5不支持在Cookie上直接设置HttpOnly属性
                String value = cookie.getValue();
                StringBuilder builder = new StringBuilder();
                builder.append("JSESSIONID=" + value + "; ");
                builder.append("Secure; ");
                builder.append("HttpOnly; ");
                Calendar cal = Calendar.getInstance();
                cal.add(Calendar.MINUTE, 30);
                Date date = cal.getTime();
                Locale locale = Locale.CHINA;
                SimpleDateFormat sdf = new SimpleDateFormat(
                        "dd-MM-yyyy HH:mm:ss", locale);
                builder.append("Expires=" + sdf.format(date));
                response.setHeader("Set-Cookie", builder.toString());
            }
        }
                
        String method = request.getMethod();  
        if("POST".equalsIgnoreCase(method)){ 
            if (getParameterMap(request)) {
                log.info("-----检测到危险字符,终止请求");
                response.setCharacterEncoding("UTF-8");
                response.getWriter().write(JSONObject.fromObject(getFailedMap("检测到疑似注入操作,终止请求")).toString());
                return;
            }
        }else{
            boolean isScri = this.filterHtmlStr(request);
            boolean isSql = this.filterSql(request);
            if (!isScri || !isSql) {
                log.info("检测到危险字符,终止请求");
                response.setCharacterEncoding("UTF-8");
                response.getWriter().write(JSONObject.fromObject(getFailedMap("检测到疑似注入操作,终止请求")).toString());
                return;
            }
        }
        
        //chain.doFilter(servletRequest, servletResponse);  
        chain.doFilter(new XSSRequestWrapper((HttpServletRequest) servletRequest), servletResponse);
    }

    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }
    /**  
     * 方法说明 :通过获取map的方法
     */   
    @SuppressWarnings("rawtypes")  
    private boolean getParameterMap(HttpServletRequest request) {  
        Map map = request.getParameterMap();  
        boolean illegalStr = false;  
        if (map != null) {  
            Set set = map.entrySet();  
            Iterator iterator = set.iterator();  
            while (iterator.hasNext()) {  
                Map.Entry entry = (Entry) iterator.next();  
                if (entry.getValue() instanceof String[]) {  
                    //System.out.println("==A==entry的key�? " + entry.getKey());  
                    String[] values = (String[]) entry.getValue();  
                   for (int i = 0; i < values.length; i++) {  
                       if(!entry.getKey().toString().equals("buildJsonSettings")){
                           if(!filterSqlFromSream(values[i]) || !filterHtmlStr(values[i])){
                               System.out.println("1====非法字符 key=" +entry.getKey().toString() + ";value=" + values[i]);  
                               illegalStr = true;
                               break;
                           } 
                       }
                    }
                } else if (entry.getValue() instanceof String) {  
                    if(!filterSqlFromSream(entry.getValue().toString()) || !filterHtmlStr(entry.getValue().toString())){
                         System.out.println("2====非法字符 key=" +entry.getKey().toString() + ";value=" + entry.getValue().toString());  
                         illegalStr = true;
                         break;
                     } 
                }  
            }  
        }  
        return illegalStr;  
} 
    public boolean filterHtmlStr(String inputStr) {

        Matcher mHtml = HTML_PATTERN.matcher(inputStr);
        if (mHtml.find()) {
            log.info("1------------------------Html str:" + inputStr);
            return false;
        }
        Matcher m = SCRIPT_PATTERN.matcher(inputStr);
        if (m.find()) {
            log.info("1------------------------js str:" + inputStr);
            return false;
        }
        return true;

    }

    public boolean filterHtmlStr(HttpServletRequest request) {

        Map paramMap = request.getParameterMap();
        String lowStr = null;
        Set> keSet = paramMap.entrySet();
        for (Iterator> itr = keSet.iterator(); itr
                .hasNext();) {
            @SuppressWarnings("rawtypes")
            Map.Entry me = (Map.Entry) itr.next();
            Object ov = me.getValue();
            String[] value = new String[1];
            if (ov instanceof String[]) {
                value = (String[]) ov;
            } else {
                value[0] = ov.toString();
            }
            for (int k = 0; k < value.length; k++) {
                lowStr = value[k];
                Matcher mHtml = HTML_PATTERN.matcher(lowStr);
                if (mHtml.find()) {
                    log.info("2------------------------Html str:" + lowStr);
                    return false;
                }
                Matcher m = SCRIPT_PATTERN.matcher(lowStr);
                if (m.find()) {
                    log.info("2------------------------js str:" + lowStr);
                    return false;
                }
            }
        }
        return true;

    }

    public boolean filterSql(HttpServletRequest request) {
        Enumeration params = request.getParameterNames();
        String sql = "";
        String name = "";
        while (params.hasMoreElements()) {
            name = params.nextElement().toString();
            log.info(String.format("name is [%s]", name));
            String[] value = request.getParameterValues(name);
            for (int i = 0; i < value.length; i++) {
                sql += value[i] + " ";
            }
        }
        sql = sql.toLowerCase();

        String badStr = ""|and|exec|execute|insert|select|delete|update|count|drop|*|chr|mid|truncate|"
                + "char|declare|sitename|net user|xp_cmdshell|or|like"|and|exec|execute|insert|create|drop|"
                + "table|from|grant|use|group_concat|column_name|"
                + "information_schema.columns|table_schema|union|where|order|by|count|*|"
                + "chr|mid|truncate|char|declare|or|like";
        String[] badStrs = badStr.split("|");
        String[] param = sql.split(" ");
        for (int j = 0; j < param.length; j++)
            for (int i = 0; i < badStrs.length; i++) {
                if (param[j].equalsIgnoreCase(badStrs[i])) {
                    log.info(String.format("1------------查询到SQL注入,输入参数:[%s]", sql));
                    return false;
                }
            }
        return true;
    }

    public boolean filterSqlFromSream(String inputJson) {
        String sql = "";
        try {
            sql = URLDecoder.decode(inputJson,"UTF-8");
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        String badStr = ""|and|exec|execute|insert|select|delete|update|count|drop|*|chr|mid|truncate|"
                + "char|declare|sitename|net user|xp_cmdshell|or|like"|and|exec|execute|insert|create|drop|"
                + "table|from|grant|use|group_concat|column_name|"
                + "information_schema.columns|table_schema|union|where|order|by|count|*|"
                + "chr|mid|truncate|char|declare|or|like";
        String[] badStrs = badStr.split("|");
        String[] param = sql.split(" ");
        for (int j = 0; j < param.length; j++)
            for (int i = 0; i < badStrs.length; i++) {
                if (param[j].equalsIgnoreCase(badStrs[i])) {
                    log.info(String.format("2------------查询到SQL注入,输入参数:[%s]", sql));
                    return false;
                }
            }
        return true;
    }

    
    public String checkSpecialWord(String str) {
        return Pattern
                .compile(
                        "[`~!@#$%^&*()+=|{}":;",[].<>/?~！@#�?%…�??&*（）—�??+|{}【�?��?�；：�?��?��?��?�，、？]")
                .matcher(str).replaceAll("").trim();
    }

    private Map getFailedMap(String message) {
        Map ret = new HashMap();
        ret.put("status", "failed");
        ret.put("message", message);
        return ret;
    }

    class XSSRequestWrapper extends HttpServletRequestWrapper {

        public XSSRequestWrapper(HttpServletRequest request) {
            super(request);
        }

        public String getParameter(String name) {
            String value = super.getParameter(name);
            if (value != null) {
                value = cleanXSS(value);
            }

            return value;
        }

        public String[] getParameterValues(String name) {
            String[] values = super.getParameterValues(name);
            if (values != null) {
                for (int i = 0; i < values.length; i++) {
                    values[i] = cleanXSS(values[i]);
                }
            }

            return values;
        }

        private String cleanXSS(String value) {
            value = value.replaceAll("<", "<").replaceAll(">", ">");
            if(value.toLowerCase().contains("") ){
                value = value.substring(0,value.toLowerCase().indexOf("script"))+value.substring(value.toLowerCase().indexOf("script")+6);
            }
            return value;
        }
    }

    
}