系统日志
系统日志的实现实际上比较简单，是通过 Spring 的 AOP ，在需要记录日志的地方声明 @SysLog，然后在 AOP 处理类中判断方法是否声明了 @SysLog，如果声明了就保存日志。
SysLogAspect.java
/**
* 系统日志，切面处理类
*
* @author chenshun
* @email sunlightcs@gmail.com
* @date 2017年3月8日 上午11:07:35
*/
@Aspect
@Component
public class SysLogAspect {
@Autowired
private SysLogService sysLogService;
@Pointcut("@annotation(io.renren.common.annotation.SysLog)")
public void logPointCut() {
}
@Around("logPointCut()")
public Object around(ProceedingJoinPoint point) throws Throwable {
long beginTime = System.currentTimeMillis();
//执行方法
Object result = point.proceed();
//执行时长(毫秒)
long time = System.currentTimeMillis() - beginTime;
//保存日志
saveSysLog(point, time);
return result;
}
private void saveSysLog(ProceedingJoinPoint joinPoint, long time) {
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
Method method = signature.getMethod();
SysLogEntity sysLog = new SysLogEntity();
SysLog syslog = method.getAnnotation(SysLog.class);
if(syslog != null){
//注解上的描述
sysLog.setOperation(syslog.value());
}
//请求的方法名
String className = joinPoint.getTarget().getClass().getName();
String methodName = signature.getName();
sysLog.setMethod(className + "." + methodName + "()");
//请求的参数
Object[] args = joinPoint.getArgs();
try{
String params = new Gson().toJson(args[0]);
sysLog.setParams(params);
}catch (Exception e){
}
//获取request
HttpServletRequest request = HttpContextUtils.getHttpServletRequest();
//设置IP地址
sysLog.setIp(IPUtils.getIpAddr(request));
//用户名
String username = ((SysUserEntity) SecurityUtils.getSubject().getPrincipal()).getUsername();
sysLog.setUsername(username);
sysLog.setTime(time);
sysLog.setCreateDate(new Date());
//保存系统日志
sysLogService.insert(sysLog);
}
}
从切面处理类可以看出，系统日志的切入点是方法执行之后。通过反射获取调用方法的注解，判断是否具有@SysLog注解，如果有就往数据库插入调用日志。值得一提的是日志中插入的访问的 ip，这个 ip 是根据 spring web 的RequestContextHolder类获取一个 thread local 的 request 对象，然后根据 request 对象的header 来获取的。使用 header 来获取 ip 而不是 getRemoteAddr()的原因是如果使用了反向代理，该方法获取不到真实的 ip。
/**
* IP地址
*
* @author chenshun
* @email sunlightcs@gmail.com
* @date 2017年3月8日 下午12:57:02
*/
public class IPUtils {
private static Logger logger = LoggerFactory.getLogger(IPUtils.class);
/**
* 获取IP地址
*
* 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址
* 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
*/
public static String getIpAddr(HttpServletRequest request) {
String ip = null;
try {
ip = request.getHeader("x-forwarded-for");
if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("Proxy-Client-IP");
}
if (StringUtils.isEmpty(ip) || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("WL-Proxy-Client-IP");
}
if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("HTTP_CLIENT_IP");
}
if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("HTTP_X_FORWARDED_FOR");
}
if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
ip = request.getRemoteAddr();
}
} catch (Exception e) {
logger.error("IPUtils ERROR ", e);
}
// //使用代理，则获取第一个IP地址
// if(StringUtils.isEmpty(ip) && ip.length() > 15) {
// if(ip.indexOf(",") > 0) {
// ip = ip.substring(0, ip.indexOf(","));
// }
// }
return ip;
}
}
本系统好像没有对具体的请求 url 进行拦截日志。其实也很简单，在 Controller 层进行拦截，然后获取方法的 Mapping 注解，拿到里面的值就行了。
XSS脚本过滤
这个项目的 XSS过滤是真的“过滤” ，而不是直接拒绝请求。
从 Springboot 的配置，FilterConfig可以看到有个叫做XSSFilter的自定义过滤器。
/**
* XSS过滤
* @author chenshun
* @email sunlightcs@gmail.com
* @date 2017-04-01 10:20
*/
public class XssFilter implements Filter {
@Override
public void init(FilterConfig config) throws ServletException {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper(
(HttpServletRequest) request);
chain.doFilter(xssRequest, response);
}
@Override
public void destroy() {
}
}
最重要的一行代码就是，这个 filter 将原始 request 包装成一个自定义的XssHttpServletRequestWrapper类。
XssHttpServletRequestWrapper.java
/**
* XSS过滤处理
* @author chenshun
* @email sunlightcs@gmail.com
* @date 2017-04-01 11:29
*/
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
//没被包装过的HttpServletRequest（特殊场景，需要自己过滤）
HttpServletRequest orgRequest;
//html过滤
private final static HTMLFilter htmlFilter = new HTMLFilter();
public XssHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
orgRequest = request;
}
@Override
public ServletInputStream getInputStream() throws IOException {
//非json类型，直接返回
if(!MediaType.APPLICATION_JSON_VALUE.equalsIgnoreCase(super.getHeader(HttpHeaders.CONTENT_TYPE))){
return super.getInputStream();
}
//为空，直接返回
String json = IOUtils.toString(super.getInputStream(), "utf-8");
if (StringUtils.isBlank(json)) {
return super.getInputStream();
}
//xss过滤
json = xssEncode(json);
final ByteArrayInputStream bis = new ByteArrayInputStream(json.getBytes("utf-8"));
return new ServletInputStream() {
@Override
public boolean isFinished() {
return true;
}
@Override
public boolean isReady() {
return true;
}
@Override
public void setReadListener(ReadListener readListener) {
}
@Override
public int read() throws IOException {
return bis.read();
}
};
}
@Override
public String getParameter(String name) {
String value = super.getParameter(xssEncode(name));
if (StringUtils.isNotBlank(value)) {
value = xssEncode(value);
}
return value;
}
@Override
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++) {
parameters[i] = xssEncode(parameters[i]);
}
return parameters;
}
@Override
public Map<String,String[]> getParameterMap() {
Map<String,String[]> map = new LinkedHashMap<>();
Map<String,String[]> parameters = super.getParameterMap();
for (String key : parameters.keySet()) {
String[] values = parameters.get(key);
for (int i = 0; i < values.length; i++) {
values[i] = xssEncode(values[i]);
}
map.put(key, values);
}
return map;
}
@Override
public String getHeader(String name) {
String value = super.getHeader(xssEncode(name));
if (StringUtils.isNotBlank(value)) {
value = xssEncode(value);
}
return value;
}
private String xssEncode(String input) {
return htmlFilter.filter(input);
}
/**
* 获取最原始的request
*/
public HttpServletRequest getOrgRequest() {
return orgRequest;
}
/**
* 获取最原始的request
*/
public static HttpServletRequest getOrgRequest(HttpServletRequest request) {
if (request instanceof XssHttpServletRequestWrapper) {
return ((XssHttpServletRequestWrapper) request).getOrgRequest();
}
return request;
}
}
我们可以看到，不论是 header, params, 还是 inputStream，都调用了xssEncode()方法，尤其是 inputStream是先读取了一遍然后转成 string 调用了xssEncode()再读成一个输入流。至于xssEncode()，就是自定义的一个 htmlFilter的方法了。
HTMLFilter这个类的代码太多，就不全部贴上了，简单的说就是将一些可能出现的 XSS 攻击脚本字符串都写到正则表达式中。一共有二十多个正则表达式
/** regex flag union representing /si modifiers in php **/
private static final int REGEX_FLAGS_SI = Pattern.CASE_INSENSITIVE | Pattern.DOTALL;
private static final Pattern P_COMMENTS = Pattern.compile("<!--(.*?)-->", Pattern.DOTALL);
private static final Pattern P_COMMENT = Pattern.compile("^!--(.*)--$", REGEX_FLAGS_SI);
private static final Pattern P_TAGS = Pattern.compile("<(.*?)>", Pattern.DOTALL);
private static final Pattern P_END_TAG = Pattern.compile("^/([a-z0-9]+)", REGEX_FLAGS_SI);
private static final Pattern P_START_TAG = Pattern.compile("^([a-z0-9]+)(.*?)(/?)$", REGEX_FLAGS_SI);
private static final Pattern P_QUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)=([\"'])(.*?)\\2", REGEX_FLAGS_SI);
private static final Pattern P_UNQUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)(=)([^\"\\s']+)", REGEX_FLAGS_SI);
private static final Pattern P_PROTOCOL = Pattern.compile("^([^:]+):", REGEX_FLAGS_SI);
private static final Pattern P_ENTITY = Pattern.compile("&#(\\d+);?");
private static final Pattern P_ENTITY_UNICODE = Pattern.compile("&#x([0-9a-f]+);?");
private static final Pattern P_ENCODE = Pattern.compile("%([0-9a-f]{2});?");
private static final Pattern P_VALID_ENTITIES = Pattern.compile("&([^&;]*)(?=(;|&|$))");
private static final Pattern P_VALID_QUOTES = Pattern.compile("(>|^)([^<]+?)(<|$)", Pattern.DOTALL);
private static final Pattern P_END_ARROW = Pattern.compile("^>");
private static final Pattern P_BODY_TO_END = Pattern.compile("<([^>]*?)(?=<|$)");
private static final Pattern P_XML_CONTENT = Pattern.compile("(^|>)([^<]*?)(?=>)");
private static final Pattern P_STRAY_LEFT_ARROW = Pattern.compile("<([^>]*?)(?=<|$)");
private static final Pattern P_STRAY_RIGHT_ARROW = Pattern.compile("(^|>)([^<]*?)(?=>)");
private static final Pattern P_AMP = Pattern.compile("&");
private static final Pattern P_QUOTE = Pattern.compile("<");
private static final Pattern P_LEFT_ARROW = Pattern.compile("<");
private static final Pattern P_RIGHT_ARROW = Pattern.compile(">");
private static final Pattern P_BOTH_ARROWS = Pattern.compile("<>");
然后将字符串用这些正则表达式匹配，并且替换字符串。下面是其中一个例子
private String balanceHTML(String s) {
if (alwaysMakeTags) {
//
// try and form html
//
s = regexReplace(P_END_ARROW, "", s);
s = regexReplace(P_BODY_TO_END, "<$1>", s);
s = regexReplace(P_XML_CONTENT, "$1<$2", s);
} else {
//
// escape stray brackets
//
s = regexReplace(P_STRAY_LEFT_ARROW, "<$1", s);
s = regexReplace(P_STRAY_RIGHT_ARROW, "$1$2><", s);
//
// the last regexp causes '<>' entities to appear
// (we need to do a lookahead assertion so that the last bracket can
// be used in the next pass of the regexp)
//
s = regexReplace(P_BOTH_ARROWS, "", s);
}
return s;
}
所以说这个系统的 XSS 脚本过滤是将一些可能的 XSS 攻击脚本都替换了。
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