SessionManagementFilter过滤器对应的类路径为
org.springframework.security.web.session.SessionManagementFilter
这个过滤器看名字就知道是管理session的了,http标签是自动配置时,默认是添加SessionManagementFilter过滤器到filterChainProxy中的,如果不想使用这个过滤器,需要做如下配置
- <security:http auto-config=“true”>
- <security:session-management session-fixation-protection=“none”/>
- </security:http>
其实在之前的过滤器中有使用到session策略了,但是没有细说。
SessionManagementFilter提供两大类功能:
1.session固化保护-通过session-fixation-protection配置
2.session并发控制-通过concurrency-control配置
下面看SessionManagementFilter的bean是如何创建的
- void createSessionManagementFilters() {
- Element sessionMgmtElt = DomUtils.getChildElementByTagName(httpElt, Elements.SESSION_MANAGEMENT);
- Element sessionCtrlElt = null;
- String sessionFixationAttribute = null;
- String invalidSessionUrl = null;
- String sessionAuthStratRef = null;
- String errorUrl = null;
- //如果配置了标签,解析标签的属性、子标签
- if (sessionMgmtElt != null) {
- sessionFixationAttribute = sessionMgmtElt.getAttribute(ATT_SESSION_FIXATION_PROTECTION);
- invalidSessionUrl = sessionMgmtElt.getAttribute(ATT_INVALID_SESSION_URL);
- sessionAuthStratRef = sessionMgmtElt.getAttribute(ATT_SESSION_AUTH_STRATEGY_REF);
- errorUrl = sessionMgmtElt.getAttribute(ATT_SESSION_AUTH_ERROR_URL);
- sessionCtrlElt = DomUtils.getChildElementByTagName(sessionMgmtElt, Elements.CONCURRENT_SESSIONS);
- //判断是否配置了concurrency-control子标签
- if (sessionCtrlElt != null) {
- //配置了并发控制标签则创建并发控制过滤器和session注册的bean定义
- createConcurrencyControlFilterAndSessionRegistry(sessionCtrlElt);
- }
- }
- if (!StringUtils.hasText(sessionFixationAttribute)) {
- sessionFixationAttribute = OPT_SESSION_FIXATION_MIGRATE_SESSION;
- } else if (StringUtils.hasText(sessionAuthStratRef)) {
- pc.getReaderContext().error(ATT_SESSION_FIXATION_PROTECTION + ” attribute cannot be used” +
- ” in combination with “ + ATT_SESSION_AUTH_STRATEGY_REF, pc.extractSource(sessionCtrlElt));
- }
- boolean sessionFixationProtectionRequired = !sessionFixationAttribute.equals(OPT_SESSION_FIXATION_NO_PROTECTION);
- BeanDefinitionBuilder sessionStrategy;
- //如果配置了concurrency-control子标签
- if (sessionCtrlElt != null) {
- assert sessionRegistryRef != null;
- //session控制策略为ConcurrentSessionControlStrategy
- sessionStrategy = BeanDefinitionBuilder.rootBeanDefinition(ConcurrentSessionControlStrategy.class);
- sessionStrategy.addConstructorArgValue(sessionRegistryRef);
- String maxSessions = sessionCtrlElt.getAttribute(“max-sessions”);
- //添加最大session数
- if (StringUtils.hasText(maxSessions)) {
- sessionStrategy.addPropertyValue(“maximumSessions”, maxSessions);
- }
- String exceptionIfMaximumExceeded = sessionCtrlElt.getAttribute(“error-if-maximum-exceeded”);
- if (StringUtils.hasText(exceptionIfMaximumExceeded)) {
- sessionStrategy.addPropertyValue(“exceptionIfMaximumExceeded”, exceptionIfMaximumExceeded);
- }
- } else if (sessionFixationProtectionRequired || StringUtils.hasText(invalidSessionUrl)
- || StringUtils.hasText(sessionAuthStratRef)) {
- //如果没有配置concurrency-control子标签
- //session控制策略是SessionFixationProtectionStrategy
- sessionStrategy = BeanDefinitionBuilder.rootBeanDefinition(SessionFixationProtectionStrategy.class);
- } else {
- //<session-management session-fixation-protection=”none”/>
- sfpf = null;
- return;
- }
- //创建SessionManagementFilter,并设置依赖的bean、property
- BeanDefinitionBuilder sessionMgmtFilter = BeanDefinitionBuilder.rootBeanDefinition(SessionManagementFilter.class);
- RootBeanDefinition failureHandler = new RootBeanDefinition(SimpleUrlAuthenticationFailureHandler.class);
- if (StringUtils.hasText(errorUrl)) {
- failureHandler.getPropertyValues().addPropertyValue(“defaultFailureUrl”, errorUrl);
- }
- sessionMgmtFilter.addPropertyValue(“authenticationFailureHandler”, failureHandler);
- sessionMgmtFilter.addConstructorArgValue(contextRepoRef);
- if (!StringUtils.hasText(sessionAuthStratRef)) {
- BeanDefinition strategyBean = sessionStrategy.getBeanDefinition();
- if (sessionFixationProtectionRequired) {
- sessionStrategy.addPropertyValue(“migrateSessionAttributes”,
- Boolean.valueOf(sessionFixationAttribute.equals(OPT_SESSION_FIXATION_MIGRATE_SESSION)));
- }
- sessionAuthStratRef = pc.getReaderContext().generateBeanName(strategyBean);
- pc.registerBeanComponent(new BeanComponentDefinition(strategyBean, sessionAuthStratRef));
- }
- if (StringUtils.hasText(invalidSessionUrl)) {
- sessionMgmtFilter.addPropertyValue(“invalidSessionUrl”, invalidSessionUrl);
- }
- sessionMgmtFilter.addPropertyReference(“sessionAuthenticationStrategy”, sessionAuthStratRef);
- sfpf = (RootBeanDefinition) sessionMgmtFilter.getBeanDefinition();
- sessionStrategyRef = new RuntimeBeanReference(sessionAuthStratRef);
- }
- //创建并发控制Filter和session注册的bean
- private void createConcurrencyControlFilterAndSessionRegistry(Element element) {
- final String ATT_EXPIRY_URL = “expired-url”;
- final String ATT_SESSION_REGISTRY_ALIAS = “session-registry-alias”;
- final String ATT_SESSION_REGISTRY_REF = “session-registry-ref”;
- CompositeComponentDefinition compositeDef =
- new CompositeComponentDefinition(element.getTagName(), pc.extractSource(element));
- pc.pushContainingComponent(compositeDef);
- BeanDefinitionRegistry beanRegistry = pc.getRegistry();
- String sessionRegistryId = element.getAttribute(ATT_SESSION_REGISTRY_REF);
- //判断是否配置了session-registry-ref属性,用于扩展
- //默认情况下使用SessionRegistryImpl类管理session的注册
- if (!StringUtils.hasText(sessionRegistryId)) {
- // Register an internal SessionRegistryImpl if no external reference supplied.
- RootBeanDefinition sessionRegistry = new RootBeanDefinition(SessionRegistryImpl.class);
- sessionRegistryId = pc.getReaderContext().registerWithGeneratedName(sessionRegistry);
- pc.registerComponent(new BeanComponentDefinition(sessionRegistry, sessionRegistryId));
- }
- String registryAlias = element.getAttribute(ATT_SESSION_REGISTRY_ALIAS);
- if (StringUtils.hasText(registryAlias)) {
- beanRegistry.registerAlias(sessionRegistryId, registryAlias);
- }
- //创建并发session控制的Filter
- BeanDefinitionBuilder filterBuilder =
- BeanDefinitionBuilder.rootBeanDefinition(ConcurrentSessionFilter.class);
- //注入session的注册实现类
- filterBuilder.addPropertyReference(“sessionRegistry”, sessionRegistryId);
- Object source = pc.extractSource(element);
- filterBuilder.getRawBeanDefinition().setSource(source);
- filterBuilder.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
- String expiryUrl = element.getAttribute(ATT_EXPIRY_URL);
- if (StringUtils.hasText(expiryUrl)) {
- WebConfigUtils.validateHttpRedirect(expiryUrl, pc, source);
- filterBuilder.addPropertyValue(“expiredUrl”, expiryUrl);
- }
- pc.popAndRegisterContainingComponent();
- concurrentSessionFilter = filterBuilder.getBeanDefinition();
- sessionRegistryRef = new RuntimeBeanReference(sessionRegistryId);
- }
接着看SessionManagementFilter过滤器执行过程
- public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
- throws IOException, ServletException {
- HttpServletRequest request = (HttpServletRequest) req;
- HttpServletResponse response = (HttpServletResponse) res;
- //省略……
- //判断当前session中是否有SPRING_SECURITY_CONTEXT属性
- if (!securityContextRepository.containsContext(request)) {
- Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
- if (authentication != null && !authenticationTrustResolver.isAnonymous(authentication)) {
- try {
- //再通过sessionStrategy执行session固化、并发处理
- //与UsernamePasswordAuthenticationFilter时处理一样,后面会仔细分析。
- sessionStrategy.onAuthentication(authentication, request, response);
- } catch (SessionAuthenticationException e) {
- SecurityContextHolder.clearContext();
- failureHandler.onAuthenticationFailure(request, response, e);
- return;
- }
- //把SecurityContext设置到当前session中
- securityContextRepository.saveContext(SecurityContextHolder.getContext(), request, response);
- } else {
- if (request.getRequestedSessionId() != null && !request.isRequestedSessionIdValid()) {
- if (invalidSessionUrl != null) {
- request.getSession();
- redirectStrategy.sendRedirect(request, response, invalidSessionUrl);
- return;
- }
- }
- }
- }
- chain.doFilter(request, response);
- }
如果项目需要使用session的并发控制,需要做如下的配置
- <session-management invalid-session-url=“/login.jsp”>
- <concurrency-control max-sessions=“1” error-if-maximum-exceeded=“true” expired-url=“/login.jsp”/>
- </session-management>
session-fixation-protection属性支持三种不同的选项允许你使用
none:使得session固化攻击失效(未配置其他属性)
migrateSession:当用户经过认证后分配一个新的session,它保证原session的所有属性移到新session中
newSession:当用户认证后,建立一个新的session,原(未认证时)session的属性不会进行移到新session中来
如果使用了标签concurrency-control,那么filterchainProxy中会添加新的过滤器
ConcurrentSessionFilter。这个过滤器的顺序在SecurityContextPersistenceFilter之前。说明未创建空的认证实体时就需要对session进行并发控制了
看ConcurrentSessionFilter执行过程
- public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
- throws IOException, ServletException {
- HttpServletRequest request = (HttpServletRequest) req;
- HttpServletResponse response = (HttpServletResponse) res;
- HttpSession session = request.getSession(false);
- if (session != null) {
- //这个SessionInformation是在执行SessionManagementFilter时通过sessionRegistry构造的并且放置在map集合中的
- SessionInformation info = sessionRegistry.getSessionInformation(session.getId());
- //如果当前session已经注册了
- if (info != null) {
- //如果当前session失效了
- if (info.isExpired()) {
- // Expired – abort processing
- //强制退出
- doLogout(request, response);
- //目标url为expired-url标签配置的属性值
- String targetUrl = determineExpiredUrl(request, info);
- //跳转到指定url
- if (targetUrl != null) {
- redirectStrategy.sendRedirect(request, response, targetUrl);
- return;
- } else {
- response.getWriter().print(“This session has been expired (possibly due to multiple concurrent “ +
- “logins being attempted as the same user).”);
- response.flushBuffer();
- }
- return;
- } else {
- // Non-expired – update last request date/time
- //session未失效,刷新时间
- info.refreshLastRequest();
- }
- }
- }
- chain.doFilter(request, response);
- }
那么分析完ConcurrentSessionFilter过滤器的执行过程,具体有什么作用呢?
简单点概括就是:从session缓存中获取当前session信息,如果发现过期了,就跳转到expired-url配置的url或者响应session失效提示信息。当前session有哪些情况会导致session失效呢?这里的失效并不是指在web容器中session的失效,而是spring security把登录成功的session封装为SessionInformation并放到注册类缓存中,如果SessionInformation的expired变量为true,则表示session已失效。
所以,ConcurrentSessionFilter过滤器主要检查SessionInformation的expired变量的值
为了能清楚解释session 并发控制的过程,现在引入UsernamePasswordAuthenticationFilter过滤器,因为该过滤器就是对登录账号进行认证的,并且在分析UsernamePasswordAuthenticationFilter过滤器时,也没有详细讲解session的处理。
UsernamePasswordAuthenticationFilter的doFilter是由父类AbstractAuthenticationProcessingFilter完成的,截取部分重要代码
- try {
- //由子类UsernamePasswordAuthenticationFilter认证
- //之前已经详细分析
- authResult = attemptAuthentication(request, response);
- if (authResult == null) {
- // return immediately as subclass has indicated that it hasn’t completed authentication
- return;
- }
- //由session策略类完成session固化处理、并发控制处理
- //如果当前认证实体的已注册session数超出最大并发的session数
- //这里会抛出AuthenticationException
- sessionStrategy.onAuthentication(authResult, request, response);
- }
- catch (AuthenticationException failed) {
- // Authentication failed
- //捕获到异常,直接跳转到失败页面或做其他处理
- unsuccessfulAuthentication(request, response, failed);
- return;
- }
session处理的方法就是这一语句
- sessionStrategy.onAuthentication(authResult, request, response);
如果是采用了并发控制session,则sessionStrategy为ConcurrentSessionControlStrategy类,具体源码:
- public void onAuthentication(Authentication authentication, HttpServletRequest request,
- HttpServletResponse response) {
- //检查是否允许认证
- checkAuthenticationAllowed(authentication, request);
- // Allow the parent to create a new session if necessary
- //执行父类SessionFixationProtectionStrategy的onAuthentication,完成session固化工作。其实就是重新建立一个session,并且把之前的session失效掉。
- super.onAuthentication(authentication, request, response);
- //向session注册类SessionRegistryImpl注册当前session、认证实体
- //实际上SessionRegistryImpl维护两个缓存列表,分别是
- //1.sessionIds(Map):key=sessionid,value=SessionInformation
- //2.principals(Map):key=principal,value=HashSet
- sessionRegistry.registerNewSession(request.getSession().getId(), authentication.getPrincipal());
- }
- //检查是否允许认证通过,如果通过直接返回,不通过,抛出AuthenticationException
- private void checkAuthenticationAllowed(Authentication authentication, HttpServletRequest request)
- throws AuthenticationException {
- //获取当前认证实体的session集合
- final List<SessionInformation> sessions = sessionRegistry.getAllSessions(authentication.getPrincipal(), false);
- int sessionCount = sessions.size();
- //获取的并发session数(由max-sessions属性配置)
- int allowedSessions = getMaximumSessionsForThisUser(authentication);
- //如果当前认证实体的已注册session数小于max-sessions,允许通过
- if (sessionCount < allowedSessions) {
- // They haven’t got too many login sessions running at present
- return;
- }
- //如果allowedSessions配置为-1,说明未限制并发session数,允许通过
- if (allowedSessions == –1) {
- // We permit unlimited logins
- return;
- }
- //如果当前认证实体的已注册session数等于max-sessions
- //判断当前的session是否已经注册过了,如果注册过了,允许通过
- if (sessionCount == allowedSessions) {
- HttpSession session = request.getSession(false);
- if (session != null) {
- // Only permit it though if this request is associated with one of the already registered sessions
- for (SessionInformation si : sessions) {
- if (si.getSessionId().equals(session.getId())) {
- return;
- }
- }
- }
- // If the session is null, a new one will be created by the parent class, exceeding the allowed number
- }
- //以上条件都不满足时,进一步处理
- allowableSessionsExceeded(sessions, allowedSessions, sessionRegistry);
- }
- protected void allowableSessionsExceeded(List<SessionInformation> sessions, int allowableSessions,
- SessionRegistry registry) throws SessionAuthenticationException {
- //判断配置的error-if-maximum-exceeded属性,如果为true,抛出异常
- if (exceptionIfMaximumExceeded || (sessions == null)) {
- throw new SessionAuthenticationException(messages.getMessage(“ConcurrentSessionControllerImpl.exceededAllowed”,
- new Object[] {new Integer(allowableSessions)},
- “Maximum sessions of {0} for this principal exceeded”));
- }
- //如果配置的error-if-maximum-exceeded为false,接下来就是取出最先注册的session信息(这里是封装到SessionInformation),然后让最先认证成功的session过期。当ConcurrentSessionFilter过滤器检查到这个过期的session,就执行session失效的处理。
- // Determine least recently used session, and mark it for invalidation
- SessionInformation leastRecentlyUsed = null;
- for (int i = 0; i < sessions.size(); i++) {
- if ((leastRecentlyUsed == null)
- || sessions.get(i).getLastRequest().before(leastRecentlyUsed.getLastRequest())) {
- leastRecentlyUsed = sessions.get(i);
- }
- }
- leastRecentlyUsed.expireNow();
- }
经过以上分析,可以这么理解
如果concurrency-control标签配置了error-if-maximum-exceeded=”true”,max-sessions=”1″,那么第二次登录时,是登录不了的。如果error-if-maximum-exceeded=”false”,那么第二次是能够登录到系统的,但是第一个登录的账号再次发起请求时,会跳转到expired-url配置的url中(如果没有配置,则显示This session has been expired (possibly due to multiple concurrent logins being attempted as the same user).提示信息)
由于篇幅过长,SessionManagementFilter、org.springframework.security.web.session.HttpSessionEventPublisher就放到下部分再分析了