從零搭建本身的SpringBoot後臺框架(十三)

時間 2019-11-17

原文原文鏈接

Hello你們好，本章咱們添加防止XSS攻擊功能。有問題能夠聯繫我mr_beany@163.com。另求各路大神指點，感謝

一：什麼是XSS

XSS攻擊全稱跨站腳本攻擊，是一種在web應用中的計算機安全漏洞，它容許惡意web用戶將代碼植入到提供給其它用戶使用的頁面中。
css

你能夠本身作個簡單嘗試：
1. 在任何一個表單內，你輸入一段簡單的js代碼：<script>for(var i=0;i<1000;i++){alert("彈死你"+i);}</script>，將其存入數據庫；
2. 在頁面上一個div元素內直接展現第一步內存入的值，你會發現彈出框出現了；java

以上兩個示例僅僅算是惡做劇，惡意用戶能作的更多，如獲取用戶信息，進行「網絡釣魚」攻擊等。node

應對XSS攻擊的其中一個方式就是後端對輸入內容進行過濾，輸入內容裏面的敏感信息直接過濾，如<script>標籤等。git

二：添加Jsoup依賴

Jsoup使用標籤白名單的機制用來進行防止XSS攻擊, 假設白名單中只容許p標籤存在, 此時在一段HTML代碼中, 只能存在p標籤 , 其餘標籤將會被清除只保留被標籤所包裹的內容，固然，Jsoup不單單能夠用來過濾，還能夠用來爬蟲，這裏先不作說明，後期會單寫一篇文章進行講解。
github

<dependency>
   <groupId>org.jsoup</groupId>
   <artifactId>jsoup</artifactId>
   <version>1.10.2</version>
</dependency>複製代碼

三：建立過濾器

在core下建立filter文件夾web

一、建立過濾規則spring

package com.example.demo.core.filter;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.safety.Whitelist;

/**
 * @author 張瑤
 * @Description: xss非法標籤過濾
 * @date 2018/5/16 20:03
 */
public class XssFilterUtil {

    /**
     * 使用自帶的basicWithImages 白名單
     * 容許的便籤有a,b,blockquote,br,cite,code,dd,dl,dt,em,i,li,ol,p,pre,q,small,span,
     * strike,strong,sub,sup,u,ul,img
     * 以及a標籤的href,img標籤的src,align,alt,height,width,title屬性
     */
    private static final Whitelist whitelist = Whitelist.basicWithImages();

    /** 配置過濾化參數,不對代碼進行格式化 */
    private static final Document.OutputSettings outputSettings = new Document.OutputSettings().prettyPrint(false);
    static {
        // 富文本編輯時一些樣式是使用style來進行實現的
        // 好比紅色字體 style="color:red;"
        // 因此須要給全部標籤添加style屬性
        whitelist.addAttributes(":all", "style");
    }

    public static String clean(String content) {
        return Jsoup.clean(content, "", whitelist, outputSettings);
    }
}
複製代碼

二、重寫請求參數處理函數，這是實現XSS過濾的關鍵，在其內重寫了getParameter，getParameterValues，getHeader等方法，對http請求內的參數進行了過濾。數據庫

package com.example.demo.core.filter;

import org.apache.commons.lang3.StringUtils;

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

/**
 * 重寫請求參數處理函數
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
    HttpServletRequest orgRequest = null;

    private boolean isIncludeRichText = false;

    public XssHttpServletRequestWrapper(HttpServletRequest request, boolean isIncludeRichText) {
        super(request);
        orgRequest = request;
        this.isIncludeRichText = isIncludeRichText;
    }

    /**
     * 覆蓋getParameter方法，將參數名和參數值都作xss過濾.
     * 若是須要得到原始的值，則經過super.getParameterValues(name)來獲取
     * getParameterNames,getParameterValues和getParameterMap也可能須要覆蓋
     */
    @Override
    public String getParameter(String name) {
        if (("content".equals(name) || name.endsWith("WithHtml")) && !isIncludeRichText) {
            return super.getParameter(name);
        }
        name = XssFilterUtil.clean(name);
        String value = super.getParameter(name);
        if (StringUtils.isNotBlank(value)) {
            value = XssFilterUtil.clean(value);
        }
        return value;
    }

    @Override
    public String[] getParameterValues(String name) {
        String[] arr = super.getParameterValues(name);
        if (arr != null) {
            for (int i = 0; i < arr.length; i++) {
                arr[i] = XssFilterUtil.clean(arr[i]);
            }
        }
        return arr;
    }


    /**
     * 覆蓋getHeader方法，將參數名和參數值都作xss過濾。<br/>
     * 若是須要得到原始的值，則經過super.getHeaders(name)來獲取<br/>
     * getHeaderNames 也可能須要覆蓋
     */
    @Override
    public String getHeader(String name) {
        name = XssFilterUtil.clean(name);
        String value = super.getHeader(name);
        if (StringUtils.isNotBlank(value)) {
            value = XssFilterUtil.clean(value);
        }
        return value;
    }

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

    /**
     * 獲取最原始的request的靜態方法
     *
     * @return
     */
    public static HttpServletRequest getOrgRequest(HttpServletRequest req) {
        if (req instanceof XssHttpServletRequestWrapper) {
            return ((XssHttpServletRequestWrapper) req).getOrgRequest();
        }
        return req;
    }

}複製代碼

三、添加過濾XSS請求的入口，在這裏經過XssHttpServletRequestWrapper將HttpServletRequest進行了封裝，filterChain.doFilter(xssRequest, response);保證了後續代碼執行request.getParameter，request.getParameterValues，request.getHeader時調用的都是XssHttpServletRequestWrapper內重寫的方法，獲取到的參數是已經進行過標籤過濾的內容，從而消除了敏感信息。apache

package com.example.demo.core.filter;


import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.StringUtils;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author 張瑤
 * @Description: 攔截防止xss注入 經過Jsoup過濾請求參數內的特定字符
 * @date 2018/5/16 20:04
 */
public class XssFilter implements Filter {

    //是否過濾富文本內容
    private static boolean IS_INCLUDE_RICH_TEXT = true;

    public List<String> excludes = new ArrayList<>();

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;
        if (handleExcludeURL(req, resp)) {
            filterChain.doFilter(request, response);
            return;
        }
        XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper((HttpServletRequest) request, IS_INCLUDE_RICH_TEXT);
        filterChain.doFilter(xssRequest, response);
    }

    private boolean handleExcludeURL(HttpServletRequest request, HttpServletResponse response) {
        if (excludes == null || excludes.isEmpty()) {
            return false;
        }
        String url = request.getServletPath();
        for (String pattern : excludes) {
            Pattern p = Pattern.compile("^" + pattern);
            Matcher m = p.matcher(url);
            if (m.find()) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        String isIncludeRichText = filterConfig.getInitParameter("isIncludeRichText");
        if (StringUtils.isNotBlank(isIncludeRichText)) {
            IS_INCLUDE_RICH_TEXT = BooleanUtils.toBoolean(isIncludeRichText);
        }
        String temp = filterConfig.getInitParameter("excludes");
        if (temp != null) {
            String[] url = temp.split(",");
            for (int i = 0; url != null && i < url.length; i++) {
                excludes.add(url[i]);
            }
        }
    }

    @Override
    public void destroy() {
    }

}
複製代碼

四：註冊過濾器

建立core→configurer→XssFilterConfigurer後端

package com.example.demo.core.configurer;

import com.example.demo.core.filter.XssFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.HashMap;
import java.util.Map;

/**
 * @author 張瑤
 * @Description:xss過濾攔截器配置文件
 * @time 2018/5/16 20:47
 */
@Configuration
public class XssFilterConfigurer {

    /**
     * xss過濾攔截器
     */
    @Bean
    public FilterRegistrationBean xssFilterRegistrationBean() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new XssFilter());
        filterRegistrationBean.setOrder(Integer.MAX_VALUE-1);
        filterRegistrationBean.setEnabled(true);
        filterRegistrationBean.addUrlPatterns("/*");
        Map<String, String> initParameters = new HashMap();
        //excludes用於配置不須要參數過濾的請求url
        initParameters.put("excludes", "/favicon.ico,/img/*,/js/*,/css/*");
        //isIncludeRichText主要用於設置富文本內容是否須要過濾
        initParameters.put("isIncludeRichText", "true");
        filterRegistrationBean.setInitParameters(initParameters);
        return filterRegistrationBean;
    }
}複製代碼