跨站点脚本编制 - SpringBoot配置XSS过滤器（基于Jsoup）

1. 跨站点脚本编制

  风险：可能会窃取或操纵客户会话和 cookie，它们可能用于模仿合法用户，从而使黑客能够以该用户身份查看或变更用户记录以及执行事务。

  原因：未对用户输入正确执行危险字符清理。

  固定值：查看危险字符注入的可能解决方案。

2. pom.xml添加依赖

<dependency>
	<groupId>org.jsoup</groupId>
	<artifactId>jsoup</artifactId>
	<version>1.11.3</version>
</dependency>
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-configuration-processor</artifactId>
	<optional>true</optional>
</dependency>

3. 添加Xss包装类

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

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

import lombok.extern.slf4j.Slf4j;

/**
 * Xss包装类
 *
 * @author CL
 *
 */
@Slf4j
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {

	/**
	 * 构造请求对象
	 *
	 * @param request
	 */
	public XssHttpServletRequestWrapper(HttpServletRequest request) {
		super(request);
	}

	/**
	 * 获取头部参数
	 *
	 * @param v 参数值
	 */
	@Override
	public String getHeader(String v) {
		String header = super.getHeader(v);
		if (header == null || "".equals(header)) {
			return header;
		}
		return Jsoup.clean(super.getHeader(v), Whitelist.relaxed());
	}

	/**
	 * 获取参数
	 *
	 * @param v 参数值
	 */
	@Override
	public String getParameter(String v) {
		String param = super.getParameter(v);
		if (param == null || "".equals(param)) {
			return param;
		}
		return Jsoup.clean(super.getParameter(v), Whitelist.relaxed());
	}

	/**
	 * 获取参数值
	 *
	 * @param v 参数值
	 */
	@Override
	public String[] getParameterValues(String v) {
		String[] values = super.getParameterValues(v);
		if (values == null) {
			return values;
		}
		int length = values.length;
		String[] resultValues = new String[length];
		for (int i = 0; i < length; i++) {
			// 过滤特殊字符
			resultValues[i] = Jsoup.clean(values[i], Whitelist.relaxed()).trim();
			if (!(resultValues[i]).equals(values[i])) {
				log.debug("XSS过滤器 => 过滤前：{} => 过滤后：{}", values[i], resultValues[i]);
			}
		}
		return resultValues;
	}
}

4. 配置文件添加配置

# 信息安全
security:
  xss:
    enable: true
    excludes:
      - /login
      - /logout
      - /images/*
      - /jquery/*
      - /layui/*

5. 添加Xss过滤器

import java.io.IOException;
import java.util.List;
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.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * Xss过滤器
 *
 * @author CL
 *
 */
@Component
@ConfigurationProperties(prefix = "security.xss")
@WebFilter(filterName = "XssFilter", urlPatterns = "/*")
public class XssFilter implements Filter {

	/**
	 * 过滤器配置对象
	 */
	FilterConfig filterConfig = null;

	/**
	 * 是否启用
	 */
	private boolean enable;

	public void setEnable(boolean enable) {
		this.enable = enable;
	}

	/**
	 * 忽略的URL
	 */
	private List<String> excludes;

	public void setExcludes(List<String> excludes) {
		this.excludes = excludes;
	}

	/**
	 * 初始化
	 */
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		this.filterConfig = filterConfig;
	}

	/**
	 * 拦截
	 */
	@Override
	public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
			throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) servletRequest;

		// 不启用或者已忽略的URL不拦截
		if (!enable || isExcludeUrl(request.getServletPath())) {
			filterChain.doFilter(servletRequest, servletResponse);
			return;
		}
		XssHttpServletRequestWrapper xssHttpServletRequestWrapper = new XssHttpServletRequestWrapper(request);
		filterChain.doFilter(xssHttpServletRequestWrapper, servletResponse);
	}

	/**
	 * 销毁
	 */
	@Override
	public void destroy() {
		this.filterConfig = null;
	}

	/**
	 * 判断是否为忽略的URL
	 *
	 * @param urlPath URL路径
	 * @return true-忽略，false-过滤
	 */
	private boolean isExcludeUrl(String url) {
		if (excludes == null || excludes.isEmpty()) {
			return false;
		}
		return excludes.stream().map(pattern -> Pattern.compile("^" + pattern)).map(p -> p.matcher(url))
				.anyMatch(Matcher::find);
	}
}