SQL盲注的解决方案

引起SQL盲注的原因：[url]http://www-01.ibm.com/support/docview.wss?uid=swg21674465[/url]
WEB安全实战（一）SQL盲注 :[url]http://blog.csdn.net/happylee6688/article/details/40615575[/url]
上面这篇文章用的是Mybaits的防注入策略，下面我们看一下，如何在进入mybatis之前，就提前处理，
如何处理呢？
HttpServletRequest在获取参数时会调用两个方法，getParameter(String name) 和
getParameterValues(String name)，我是不是可以继承HttpServletRequest，重写这两个方法，来解决SQL盲注呢？答案是可以的。具体请看下文：

HttpServletRequest包装类：

public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
	private String[]filterChars;
	private String[]replaceChars;
	public XssHttpServletRequestWrapper(HttpServletRequest request,String filterChar,String replaceChar,String splitChar) {
		super(request);
		if(filterChar!=null&&filterChar.length()>0){
			filterChars=filterChar.split(splitChar);
		}
		if(replaceChar!=null&&replaceChar.length()>0){
			replaceChars=replaceChar.split(splitChar);
		}
	}
	public String getQueryString() {
		String value = super.getQueryString();
		if (value != null) {
			value = xssEncode(value);
			value = value.replaceAll("＆", "&").replaceAll("＝", "=");
		}
		return value;
	}

	/**
	 * 覆盖getParameter方法，将参数名和参数值都做xss过滤。

	 * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取

	 * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖
	 */
	public String getParameter(String name) {
		String value = super.getParameter(xssEncode(name));
		if (value != null) {
		         //关键处理
			value = xssEncode(value);
		}
		return value;
	}

	public String[] getParameterValues(String name) {
		String[]parameters=super.getParameterValues(name);
		if (parameters==null||parameters.length == 0) {
			return null;
		}
		for (int i = 0; i < parameters.length; i++) {
		         //关键处理
			parameters[i] = xssEncode(parameters[i]);
		}
		return parameters;
	}

	/**
	 * 覆盖getHeader方法，将参数名和参数值都做xss过滤。

	 * 如果需要获得原始的值，则通过super.getHeaders(name)来获取
 getHeaderNames 也可能需要覆盖
	 */
	public String getHeader(String name) {

		String value = super.getHeader(xssEncode(name));
		if (value != null) {
		        //关键处理
			value = xssEncode(value);
		}
		return value;
	}

	/**
	 * 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  String xssEncode(String s) {
		if (s == null || s.equals("")) {
			return s;
		}
		try {
			// 前端如果提交的内容中包含%会出异常，先将非URL编码的%替换成全角
			s = s.replaceAll("%(?![0-9a-fA-F][0-9a-fA-F])", "％");
			s = URLDecoder.decode(s, UTF8);
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		for (int i = 0; i < filterChars.length; i++) {
			if(s.contains(filterChars[i])){
				s=s.replace(filterChars[i], replaceChars[i]);
			}
		}
		return s;
	}

	public static void main(String[] args){
		String s = "%预期%AG收益20%年%20化%E利%EA率%";
		s = s.replaceAll("%(?![0-9a-fA-F][0-9a-fA-F])", "％");
		System.out.println(s);
	}
}

//SQL过滤器

public class XssFilter implements Filter {
	private String filterChar;//需要过滤的字符串
	private String replaceChar;//替代需要过滤的字符串对应的字符串
	private String splitChar;//分隔符
	private String excludeUrls;//不需要过滤的连接
	FilterConfig filterConfig = null;
	public void init(FilterConfig filterConfig) throws ServletException {
		this.filterChar=filterConfig.getInitParameter("FilterChar");
		this.replaceChar=filterConfig.getInitParameter("ReplaceChar");
		this.splitChar=filterConfig.getInitParameter("SplitChar");
		this.excludeUrls=filterConfig.getInitParameter("excludeUrls");
		this.filterConfig = filterConfig;
	}
	public void destroy() {
		this.filterConfig = null;
	}

	public void doFilter(ServletRequest request, ServletResponse response,
	        FilterChain chain) throws IOException, ServletException {
		//如果是不需要的过滤的url，直接到下一个filter
		if(isExcludeUrl(request)){
			chain.doFilter(request, response);
		}else{
		//否则包装HttpServletRequest，替换参数
			chain.doFilter(new XssHttpServletRequestWrapper((HttpServletRequest) request,filterChar,replaceChar,splitChar), response);
		}
	}
	private boolean isExcludeUrl(ServletRequest request){
		boolean exclude=false;
		if(StringUtils.isNotBlank(excludeUrls)){
			 String[]excludeUrl=excludeUrls.split(splitChar);
			 if(excludeUrl!=null&&excludeUrl.length>0){
				 for(String url:excludeUrl){
					 if(URLHelper.getURI((HttpServletRequest)request).startsWith(url)){
						 exclude=true;
					 }
				 }
			 }
		}
		return exclude;
	}

}

配置filter

    XssFilter
    com.web.XssFilter
    
      
      excludeUrls
      /test@/group/add@/find
    
    
      
      SplitChar
      @
    
    
     
      FilterChar
      ;@&@<@'@"@\@#@%@select @delete @update @insert @or @and @>
    
    
      
      ReplaceChar
      ；@＆@＜@‘@“@＼@＃@％@ｓｅｌｅｃｔ @ｄｅｌｅｔｅ @ｕｐｄａｔｅ @ｉｎｓｅｒｔ @ｏｒ@ａｎｄ@＞
    

总结：
解决的办法，重写Requets的获取参数方法，并在过滤器中，根据是否需要过滤URL，来确定是否需要包装Request。