Xss解决方案

本文介绍解决Xss跨站脚本漏洞的方法，本方法解决思路为对request请求进行包装，重写request相关方法，对参数进行转义及过滤。注意此方案只适用于通过request获取普通参数，对于传输的json方式的参数无效，如需解决json方式参数，需要在json序列化或者反序列化时对内容进行转义，解决思路一致。
需要的类主要包括：

1. XssFiter.java

import java.io.IOException;
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.HttpServletRequest;
public class XssFiter implements Filter {
     

    public void init(FilterConfig filterConfig) throws ServletException {
     

    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
     
        HttpServletRequest req = (HttpServletRequest) request;
        XssAndHttpServletRequestWrapper xssRequestWrapper = new XssAndHttpServletRequestWrapper(req);
        chain.doFilter(xssRequestWrapper, response);
    }

    public void destroy() {
     

    }

}

2. XssAndHttpServletRequestWrapper

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

public class XssAndHttpServletRequestWrapper extends HttpServletRequestWrapper {
     
	HttpServletRequest request;

	public XssAndSqlHttpServletRequestWrapper(HttpServletRequest request) {
     
		super(request);
		this.request = request;
	}

	@Override
	public String getParameter(String name) {
     
		String value = super.getParameter(name);
		// System.out.println("name:" + name + "," + value);
		if (value != null) {
     
			// 转换Html
			value = XssUtil.cleanXss(value);
		}
		return value;
	}

	@Override
	public String getHeader(String name) {
     
		return XssUtil.cleanXss(super.getHeader(name));
	}

	@Override
	public String getQueryString() {
     
		return XssUtil.cleanXss(super.getQueryString());
	}

	@Override
	public String[] getParameterValues(String parameter) {
     
		String[] values = super.getParameterValues(parameter);
		if (values == null) {
     
			return null;
		}
		int count = values.length;
		String[] encodedValues = new String[count];
		for (int i = 0; i < count; i++) {
     
			encodedValues[i] = XssUtil.cleanXss(values[i]);
		}
		return encodedValues;
	}

}

3. XssUtil.java

 import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class XssUtil {
     

	private static final String REGEX_SCRIPT = "]*?>[\\s\\S]*?<\\/script>"; // 定义script的正则表达式
	private static final String REGEX_STYLE = "]*?>[\\s\\S]*?<\\/style>"; // 定义style的正则表达式
	private static final String REGEX_HTML = "<[^>]+>"; // 定义HTML标签的正则表达式
	// private static final String REGEX_SPACE = "\\s*|\t|\r|\n";// 定义空格回车换行符

	/**
	 * 过滤掉script标签
	 * 
	 * @param htmlStr
	 * @return
	 */
	public static String delScriptTag(String htmlStr) {
     
		if (htmlStr == null)
			return null;
		Pattern p_script = Pattern.compile(REGEX_SCRIPT, Pattern.CASE_INSENSITIVE);
		Matcher m_script = p_script.matcher(htmlStr);
		htmlStr = m_script.replaceAll(""); // 过滤script标签
		return htmlStr;
	}

	/**
	 * 过滤掉style标签
	 * 
	 * @param htmlStr
	 * @return
	 */
	public static String delStyleTag(String htmlStr) {
     
		if (htmlStr == null)
			return null;
		Pattern p_style = Pattern.compile(REGEX_STYLE, Pattern.CASE_INSENSITIVE);
		Matcher m_style = p_style.matcher(htmlStr);
		htmlStr = m_style.replaceAll(""); // 过滤style标签*/
		return htmlStr;
	}

	/**
	 * @param htmlStr
	 * @return 删除Html标签
	 */
	public static String delHTMLTag(String htmlStr) {
     
		if (htmlStr == null)
			return null;
		Pattern p_html = Pattern.compile(REGEX_HTML, Pattern.CASE_INSENSITIVE);
		Matcher m_html = p_html.matcher(htmlStr);
		htmlStr = m_html.replaceAll(""); // 过滤html标签
		return htmlStr; // 返回文本字符串
	}

	/**
	 * 将html标签中的<>进行转义，如只有"<"或者">"则不进行转义
	 */
	public static String escapeHtml(String htmlStr) {
     
		if (htmlStr == null)
			return null;
		Pattern p_script = Pattern.compile(REGEX_HTML, Pattern.CASE_INSENSITIVE);
		Matcher m_script = p_script.matcher(htmlStr);
		while (m_script.find()) {
     
			String str = m_script.group();
			String str_target = str.replaceAll("<", "<").replaceAll(">", ">");
			htmlStr = htmlStr.replaceAll(str, str_target);
		}
		return htmlStr;
	}

	/**
	 * 转义html标签
	 * 
	 * @param input
	 * @return
	 */
	public static String cleanXss(String input) {
     
		if (input == null)
			return null;
		return escapeHtml(delStyleTag(delScriptTag(input)));
	}

	
	public static void main(String[] args) {
     

		System.out.println(cleanXss("<'script>"));
		// escapeStr("<是打发第三方>1212《dd》
	}
}

4. web.xml配置示例

 <filter>
	<filter-name>xssFilterChain</filter-name>
	<filter-class>xxxxxxx.xxxxxx.XssFiter</filter-class>
</filter>
<filter-mapping>
	<filter-name>xssFilterChain</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>

5. XssUtil类中主要给出了过滤掉script标签、style标签的内容，以及将html标签中的<>转义为<>，在使用中可根据实际情况，重写cleanXss方法