Spring Security认证过程

时间 2019-11-08 标签 spring security 认证过程

Spring Security是一个可以为基于Spring的企业应用系统提供声明式的安全访问控制解决方案的安全框架。它提供了一组能够在Spring应用上下文中配置的Bean，充分利用了Spring IoC，DI（控制反转Inversion of Control ,DI:Dependency Injection 依赖注入）和AOP（面向切面编程）功能，为应用系统提供声明式的安全访问控制功能，减小了为企业系统安全控制编写大量重复代码的工做。java

类图

为了方便理解Spring Security认证流程，特地画了以下的类图，包含相关的核心认证类 git

概述

核心验证器github

AuthenticationManager

该对象提供了认证方法的入口，接收一个Authentiaton对象做为参数;算法

public interface AuthenticationManager {
	Authentication authenticate(Authentication authentication)
			throws AuthenticationException;
}

ProviderManager

它是 AuthenticationManager 的一个实现类，提供了基本的认证逻辑和方法；它包含了一个 List<AuthenticationProvider> 对象，经过 AuthenticationProvider 接口来扩展出不一样的认证提供者(当Spring Security默认提供的实现类不能知足需求的时候能够扩展AuthenticationProvider 覆盖supports(Class<?> authentication) 方法)；spring

验证逻辑

AuthenticationManager 接收 Authentication 对象做为参数，并经过 authenticate(Authentication) 方法对其进行验证；AuthenticationProvider实现类用来支撑对 Authentication 对象的验证动做；UsernamePasswordAuthenticationToken实现了 Authentication主要是将用户输入的用户名和密码进行封装，并供给 AuthenticationManager 进行验证；验证完成之后将返回一个认证成功的 Authentication 对象；数据库

Authentication

Authentication对象中的主要方法编程

public interface Authentication extends Principal, Serializable {
	//#1.权限结合，可以使用AuthorityUtils.commaSeparatedStringToAuthorityList("admin,ROLE_ADMIN")返回字符串权限集合
	Collection<? extends GrantedAuthority> getAuthorities();
	//#2.用户名密码认证时能够理解为密码
	Object getCredentials();
	//#3.认证时包含的一些信息。
	Object getDetails();
	//#4.用户名密码认证时可理解时用户名
	Object getPrincipal();
	#5.是否被认证，认证为true	
	boolean isAuthenticated();
	#6.设置是否能被认证
	void setAuthenticated(boolean isAuthenticated) throws IllegalArgumentException;

ProviderManager

ProviderManager是AuthenticationManager的实现类，提供了基本认证明现逻辑和流程；安全

public Authentication authenticate(Authentication authentication)
			throws AuthenticationException {
		//#1.获取当前的Authentication的认证类型
		Class<? extends Authentication> toTest = authentication.getClass();
		AuthenticationException lastException = null;
		Authentication result = null;
		boolean debug = logger.isDebugEnabled();
		//#2.遍历全部的providers使用supports方法判断该provider是否支持当前的认证类型，不支持的话继续遍历
		for (AuthenticationProvider provider : getProviders()) {
			if (!provider.supports(toTest)) {
				continue;
			}

			if (debug) {
				logger.debug("Authentication attempt using "
						+ provider.getClass().getName());
			}

			try {
				#3.支持的话调用provider的authenticat方法认证
				result = provider.authenticate(authentication);

				if (result != null) {
					#4.认证经过的话从新生成Authentication对应的Token
					copyDetails(authentication, result);
					break;
				}
			}
			catch (AccountStatusException e) {
				prepareException(e, authentication);
				// SEC-546: Avoid polling additional providers if auth failure is due to
				// invalid account status
				throw e;
			}
			catch (InternalAuthenticationServiceException e) {
				prepareException(e, authentication);
				throw e;
			}
			catch (AuthenticationException e) {
				lastException = e;
			}
		}

		if (result == null && parent != null) {
			// Allow the parent to try.
			try {
				#5.若是#1 没有验证经过，则使用父类型AuthenticationManager进行验证
				result = parent.authenticate(authentication);
			}
			catch (ProviderNotFoundException e) {
				// ignore as we will throw below if no other exception occurred prior to
				// calling parent and the parent
				// may throw ProviderNotFound even though a provider in the child already
				// handled the request
			}
			catch (AuthenticationException e) {
				lastException = e;
			}
		}
		#6. 是否擦出敏感信息
		if (result != null) {
			if (eraseCredentialsAfterAuthentication
					&& (result instanceof CredentialsContainer)) {
				// Authentication is complete. Remove credentials and other secret data
				// from authentication
				((CredentialsContainer) result).eraseCredentials();
			}

			eventPublisher.publishAuthenticationSuccess(result);
			return result;
		}

		// Parent was null, or didn't authenticate (or throw an exception).

		if (lastException == null) {
			lastException = new ProviderNotFoundException(messages.getMessage(
					"ProviderManager.providerNotFound",
					new Object[] { toTest.getName() },
					"No AuthenticationProvider found for {0}"));
		}

		prepareException(lastException, authentication);

		throw lastException;
	}

遍历全部的 Providers，而后依次执行该 Provider 的验证方法
- 若是某一个 Provider 验证成功，则跳出循环再也不执行后续的验证；
- 若是验证成功，会将返回的 result 既 Authentication 对象进一步封装为 Authentication Token；好比 UsernamePasswordAuthenticationToken、RememberMeAuthenticationToken 等；这些 Authentication Token 也都继承自 Authentication 对象；
若是 #1 没有任何一个 Provider 验证成功，则试图使用其 parent Authentication Manager 进行验证；
是否须要擦除密码等敏感信息；

AuthenticationProvider

ProviderManager 经过 AuthenticationProvider 扩展出更多的验证提供的方式；而 AuthenticationProvider 自己也就是一个接口，从类图中咱们能够看出它的实现类AbstractUserDetailsAuthenticationProvider 和AbstractUserDetailsAuthenticationProvider的子类DaoAuthenticationProvider 。DaoAuthenticationProvider 是Spring Security中一个核心的Provider,对全部的数据库提供了基本方法和入口。app

DaoAuthenticationProvider

DaoAuthenticationProvider主要作了如下事情框架

对用户身份尽心加密操做；

#1.可直接返回BCryptPasswordEncoder，也能够本身实现该接口使用本身的加密算法核心方法String encode(CharSequence rawPassword);和boolean matches(CharSequence rawPassword, String encodedPassword);

private PasswordEncoder passwordEncoder;

2. 实现了 `AbstractUserDetailsAuthenticationProvider` 两个抽象方法，
	1. 获取用户信息的扩展点
	```java
protected final UserDetails retrieveUser(String username,
			UsernamePasswordAuthenticationToken authentication)
			throws AuthenticationException {
		UserDetails loadedUser;

		try {
			loadedUser = this.getUserDetailsService().loadUserByUsername(username);
		}

主要是经过注入`UserDetailsService`接口对象，并调用其接口方法 `loadUserByUsername(String username)` 获取获得相关的用户信息。`UserDetailsService`接口很是重要。
2. 实现 additionalAuthenticationChecks 的验证方法(主要验证密码)；

AbstractUserDetailsAuthenticationProvider

AbstractUserDetailsAuthenticationProvider为DaoAuthenticationProvider提供了基本的认证方法；

public Authentication authenticate(Authentication authentication)
			throws AuthenticationException {
		Assert.isInstanceOf(UsernamePasswordAuthenticationToken.class, authentication,
				messages.getMessage(
						"AbstractUserDetailsAuthenticationProvider.onlySupports",
						"Only UsernamePasswordAuthenticationToken is supported"));

		// Determine username
		String username = (authentication.getPrincipal() == null) ? "NONE_PROVIDED"
				: authentication.getName();

		boolean cacheWasUsed = true;
		UserDetails user = this.userCache.getUserFromCache(username);

		if (user == null) {
			cacheWasUsed = false;

			try {
				#1.获取用户信息由子类实现即DaoAuthenticationProvider
				user = retrieveUser(username,
						(UsernamePasswordAuthenticationToken) authentication);
			}
			catch (UsernameNotFoundException notFound) {
				logger.debug("User '" + username + "' not found");

				if (hideUserNotFoundExceptions) {
					throw new BadCredentialsException(messages.getMessage(
							"AbstractUserDetailsAuthenticationProvider.badCredentials",
							"Bad credentials"));
				}
				else {
					throw notFound;
				}
			}

			Assert.notNull(user,
					"retrieveUser returned null - a violation of the interface contract");
		}

		try {
			#2.前检查由DefaultPreAuthenticationChecks类实现（主要判断当前用户是否锁定，过时，冻结User接口）
			preAuthenticationChecks.check(user);
			#3.子类实现
			additionalAuthenticationChecks(user,
					(UsernamePasswordAuthenticationToken) authentication);
		}
		catch (AuthenticationException exception) {
			if (cacheWasUsed) {
				// There was a problem, so try again after checking
				// we're using latest data (i.e. not from the cache)
				cacheWasUsed = false;
				user = retrieveUser(username,
						(UsernamePasswordAuthenticationToken) authentication);
				preAuthenticationChecks.check(user);
				additionalAuthenticationChecks(user,
						(UsernamePasswordAuthenticationToken) authentication);
			}
			else {
				throw exception;
			}
		}
		#4.检测用户密码是否过时对应#2 的User接口
		postAuthenticationChecks.check(user);

		if (!cacheWasUsed) {
			this.userCache.putUserInCache(user);
		}

		Object principalToReturn = user;

		if (forcePrincipalAsString) {
			principalToReturn = user.getUsername();
		}

		return createSuccessAuthentication(principalToReturn, authentication, user);
	}

AbstractUserDetailsAuthenticationProvider主要实现了AuthenticationProvider的接口方法 authenticate 并提供了相关的验证逻辑；

获取用户返回UserDetails AbstractUserDetailsAuthenticationProvider定义了一个抽象的方法

protected abstract UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException;

2. 三步验证工做
	1. preAuthenticationChecks
	2. additionalAuthenticationChecks（抽象方法，子类实现）
	3. postAuthenticationChecks
3. 将已经过验证的用户信息封装成 UsernamePasswordAuthenticationToken 对象并返回；该对象封装了用户的身份信息，以及相应的权限信息，相关源码以下，
	```java
protected Authentication createSuccessAuthentication(Object principal,
		UsernamePasswordAuthenticationToken result = new UsernamePasswordAuthenticationToken(
				principal, authentication.getCredentials(),
				authoritiesMapper.mapAuthorities(user.getAuthorities()));
		result.setDetails(authentication.getDetails());

		return result;
	}

UserDetailsService

UserDetailsService是一个接口，提供了一个方法

public interface UserDetailsService {
	UserDetails loadUserByUsername(String username) throws UsernameNotFoundException;
}

经过用户名 username 调用方法 loadUserByUsername 返回了一个UserDetails接口对象（对应AbstractUserDetailsAuthenticationProvider的三步验证方法）；

public interface UserDetails extends Serializable {
	#1.权限集合
	Collection<? extends GrantedAuthority> getAuthorities();
	#2.密码	
	String getPassword();
	#3.用户民
	String getUsername();
	#4.用户是否过时
	boolean isAccountNonExpired();
	#5.是否锁定	
	boolean isAccountNonLocked();
	#6.用户密码是否过时	
	boolean isCredentialsNonExpired();
	#7.帐号是否可用（可理解为是否删除）
	boolean isEnabled();
}

Spring 为UserDetailsService默认提供了一个实现类 org.springframework.security.core.userdetails.jdbc.JdbcDaoImpl

JdbcUserDetailsManager

该实现类主要是提供基于JDBC对 User 进行增、删、查、改的方法

public class JdbcUserDetailsManager extends JdbcDaoImpl implements UserDetailsManager,
		GroupManager {
	// ~ Static fields/initializers
	// =====================================================================================

	// UserDetailsManager SQL
	#1.定义了一些列对数据库操做的语句
	public static final String DEF_CREATE_USER_SQL = "insert into users (username, password, enabled) values (?,?,?)";
	public static final String DEF_DELETE_USER_SQL = "delete from users where username = ?";
	public static final String DEF_UPDATE_USER_SQL = "update users set password = ?, enabled = ? where username = ?";
	public static final String DEF_INSERT_AUTHORITY_SQL = "insert into authorities (username, authority) values (?,?)";
	public static final String DEF_DELETE_USER_AUTHORITIES_SQL = "delete from authorities where username = ?";
	public static final String DEF_USER_EXISTS_SQL = "select username from users where username = ?";
	public static final String DEF_CHANGE_PASSWORD_SQL = "update users set password = ? where username = ?";

InMemoryUserDetailsManager

该实现类主要是提供基于内存对 User 进行增、删、查、改的方法 `public class InMemoryUserDetailsManager implements UserDetailsManager { protected final Log logger = LogFactory.getLog(getClass()); #1.用MAP 存储 private final Map<String, MutableUserDetails> users = new HashMap<String, MutableUserDetails>();

private AuthenticationManager authenticationManager;

public InMemoryUserDetailsManager() {
}

public InMemoryUserDetailsManager(Collection<UserDetails> users) {
	for (UserDetails user : users) {
		createUser(user);
	}
}`

总结

UserDetailsService接口做为桥梁，是DaoAuthenticationProvier与特定用户信息来源进行解耦的地方，UserDetailsService由UserDetails和UserDetailsManager所构成；UserDetails和UserDetailsManager各司其责，一个是对基本用户信息进行封装，一个是对基本用户信息进行管理；

特别注意，UserDetailsService、UserDetails以及UserDetailsManager都是可被用户自定义的扩展点，咱们能够继承这些接口提供本身的读取用户来源和管理用户的方法，好比咱们能够本身实现一个与特定 ORM 框架，好比 Mybatis 或者 Hibernate，相关的UserDetailsService和UserDetailsManager；

Spring Security认证过程

类图

概述

AuthenticationManager

ProviderManager

验证逻辑

Authentication

ProviderManager

AuthenticationProvider

DaoAuthenticationProvider

AbstractUserDetailsAuthenticationProvider

UserDetailsService

JdbcUserDetailsManager

InMemoryUserDetailsManager

总结

时序图