Spring securty＜四＞认证的源码解析

末蓝、 2021-09-25 14:58 446阅读 0赞

# Spring securty<四> 认证的源码解析 #

### 文章目录 ###

*  Spring securty<四> 认证的源码解析
 *   *  1、简介
     *  2、认证（登录）
     *  3、认证的源码解析
     *   *  1、是否是指定的url的请求
         *  2、验证帐号密码信息
         *   *  2.1、帐号密码构建一个 UsernamePasswordAuthenticationToken 对象
             *  2.2、获取权限管理器，认证权限（重点，要掌握、通透理解）
             *   *  2.2.1、先看第二个步骤：认证的类型是不是匹配的，例如：帐号密码登录、手机号+验证码登录、扫码登录等
                 *  2.2.2、第三个步骤：拿到需要认证的信息\`Authentication authentication\`后，进行认证操作；
         *  3、验证成功后，存储会话信息
         *  4、失败之后，走失败的异常处理
         *  5、是否继续链路
         *  6、登录成功后，成功处理器
     *  4、总结-最终认证流程

本地项目的基础环境

<table> 
 <thead> 
  <tr> 
   <th align="center">环境</th> 
   <th align="center">版本</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="center">jdk</td> 
   <td align="center">1.8.0_201</td> 
  </tr> 
  <tr> 
   <td align="center">maven</td> 
   <td align="center">3.6.0</td> 
  </tr> 
  <tr> 
   <td align="center">Spring-boot</td> 
   <td align="center">2.3.3.RELEASE</td> 
  </tr> 
 </tbody> 
</table>

## 1、简介 ##

spring security是一个提供身份验证、授权和防止常见攻击的框架，它对命令式和反应式应用程序都有一流的支持，是保护基于Spring的应用程序的事实上的标准。

详细可以参看[《spring security官网》][spring security]

## 2、认证（登录） ##

通过之前的两篇文章的介绍，应该也比较清楚了基本的概念了安全框架里的核心的概念了，从这篇开始，主要开始细化讲代码层面上的开发了；在权限框架中，认证这个部分，也算是最难的了，之后的几篇，也是主要讲述认证相关的。

[《Spring securty＜一＞ 简介入门案例》][Spring securty_]

[《Spring securty＜二＞ 配置项详解》][Spring securty_ 1]

[《Spring securty＜三＞ 认证案例代码》][Spring securty_ 2]

## 3、认证的源码解析 ##

这篇文章使用的案例，为[《Spring securty＜三＞ 认证案例代码》][Spring securty_ 2]

整个认证的流程，都是**基于拦截器链的**，这句话也是反复说明的，请求的过程，大概是如下过程：

![1.png][]

可以看到，http请求，其实在图中第二步，就已经被拦截器处理了，没有进入`SpringMvc`的前置派发器中；

`spring Security`安全框架，最主要的认证部分，就是`org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter`这个拦截器了，一般拦截器执行方法`doFilter`方法；这个拦截器，是继承AbstractAuthenticationProcessingFilter\`的doFilter方法：

`org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter()`

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
    			throws IOException, ServletException { 
    		HttpServletRequest request = (HttpServletRequest) req;
    		HttpServletResponse response = (HttpServletResponse) res;
            // 1、是否是指定的url的请求
    		if (!requiresAuthentication(request, response)) { 
    			chain.doFilter(request, response);
    			return;
    		}
    		if (logger.isDebugEnabled()) { 
    			logger.debug("Request is to process authentication");
    		}
    		Authentication authResult;
    		try { 
                //2、验证帐号密码信息
    			authResult = attemptAuthentication(request, response);
    			if (authResult == null) { 
    				// return immediately as subclass has indicated that it hasn't completed
    				// authentication
    				return;
    			}
                //3、验证成功后，存储会话信息
    			sessionStrategy.onAuthentication(authResult, request, response);
    		}
    		catch (InternalAuthenticationServiceException failed) { 
    			logger.error(
    					"An internal error occurred while trying to authenticate the user.",
    					failed);
                //4、失败之后，走失败的异常处理
    			unsuccessfulAuthentication(request, response, failed);
    			return;
    		}
    		catch (AuthenticationException failed) { 
    			// Authentication failed 4.1、失败之后，走失败的异常处理
    			unsuccessfulAuthentication(request, response, failed);
    			return;
    		}
    		// Authentication success 5、是否继续链路
    		if (continueChainBeforeSuccessfulAuthentication) { 
    			chain.doFilter(request, response);
    		}
            // 6、登录成功后，成功处理器
    		successfulAuthentication(request, response, chain, authResult);
    	}

上述的代码中，我分别按照整个认证的步骤，写了注释，大概是6个步骤；下面，我们每个步骤，进行拆解，详解：

### 1、是否是指定的url的请求 ###

// 1、是否是指定的url的请求
    		if (!requiresAuthentication(request, response)) { 
    			chain.doFilter(request, response);
    			return;
    		}

注释也在下面看到了，拿到当前 request 对象的中的请求路径，跟构造方法（初始化）里的url做对比，如果是，就继续执行第二步；

protected boolean requiresAuthentication(HttpServletRequest request,
    			HttpServletResponse response) { 
    		return requiresAuthenticationRequestMatcher.matches(request);
    	}
    
    	/** 构造方法 * @param defaultFilterProcessesUrl the default value for <tt>filterProcessesUrl</tt>. */
    	protected AbstractAuthenticationProcessingFilter(String defaultFilterProcessesUrl) { 
    		setFilterProcessesUrl(defaultFilterProcessesUrl);
    	}
    
    	/** 构造方法 * Creates a new instance * * @param requiresAuthenticationRequestMatcher the {@link RequestMatcher} used to * determine if authentication is required. Cannot be null. */
    	protected AbstractAuthenticationProcessingFilter(
    			RequestMatcher requiresAuthenticationRequestMatcher) { 
    		Assert.notNull(requiresAuthenticationRequestMatcher,
    				"requiresAuthenticationRequestMatcher cannot be null");
    		this.requiresAuthenticationRequestMatcher = requiresAuthenticationRequestMatcher;
    	}

不知道，大家注意了没有，我在上述的案例代码中，表单提交的url设置的`/auth/login`，我请求的地址，也是同一个；

![f4bc567cc6d917b7a771f4aa086aaede.png][]

### 2、验证帐号密码信息 ###

authResult = attemptAuthentication(request, response);

方法进去之后，可以看到，调用`org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter`实现的方法

public Authentication attemptAuthentication(HttpServletRequest request,
    			HttpServletResponse response) throws AuthenticationException { 
    		if (postOnly && !request.getMethod().equals("POST")) { 
    			throw new AuthenticationServiceException(
    					"Authentication method not supported: " + request.getMethod());
    		}
        	//1、从请求参数中，获取username、password
    		String username = obtainUsername(request);
    		String password = obtainPassword(request);
    		if (username == null) { 
    			username = "";
    		}
    		if (password == null) { 
    			password = "";
    		}
    		username = username.trim();
        	//2、 帐号密码构建一个 UsernamePasswordAuthenticationToken 对象
    		UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(
    				username, password);
    		// Allow subclasses to set the "details" property
    		setDetails(request, authRequest); //3、 设置一些属性
        	//4、获取权限管理器，认证权限
    		return this.getAuthenticationManager().authenticate(authRequest);
    	}

步骤1和步骤3，代码比较简单，也就不在解释了；**重点说下步骤2和步骤4**，认证的过程

#### 2.1、帐号密码构建一个 UsernamePasswordAuthenticationToken 对象 ####

`UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken( username, password);`

/** * This constructor can be safely used by any code that wishes to create a * <code>UsernamePasswordAuthenticationToken</code>, as the {@link #isAuthenticated()} * will return <code>false</code>. * */
    	public UsernamePasswordAuthenticationToken(Object principal, Object credentials) { 
    		super(null);
    		this.principal = principal;
    		this.credentials = credentials;
    		setAuthenticated(false);
    	}
    
    	/** * This constructor should only be used by <code>AuthenticationManager</code> or * <code>AuthenticationProvider</code> implementations that are satisfied with * producing a trusted (i.e. {@link #isAuthenticated()} = <code>true</code>) * authentication token. * * @param principal * @param credentials * @param authorities */
    	public UsernamePasswordAuthenticationToken(Object principal, Object credentials,
    			Collection<? extends GrantedAuthority> authorities) { 
    		super(authorities);
    		this.principal = principal;
    		this.credentials = credentials;
    		super.setAuthenticated(true); // must use super, as we override
    	}

从代码中，可以看到，创建对象的时候，使用了第一个构造方法，主要注意`setAuthenticated(false);`这个验证信息，设置成了false，表示没有认证，只是构建了对象；

#### 2.2、获取权限管理器，认证权限（重点，要掌握、通透理解） ####

**这节是重点，一定要通透，关系到后面，能不能自定义开发，整合其他的各种登录**

`this.getAuthenticationManager().authenticate(authRequest)`

找到认证管理器`AuthenticationManager`的实现类`org.springframework.security.authentication.ProviderManager`，查看认证方法`authenticate`

public Authentication authenticate(Authentication authentication)
    			throws AuthenticationException { 
    		Class<? extends Authentication> toTest = authentication.getClass();
    		AuthenticationException lastException = null;
    		AuthenticationException parentException = null;
    		Authentication result = null;
    		Authentication parentResult = null;
    		boolean debug = logger.isDebugEnabled();
        	// 1、主要业务，获取所有的认证提供者，遍历去认证权限
    		for (AuthenticationProvider provider : getProviders()) { 
                // 2、判断是否是指定的Authentication类型，不是就跳过
    			if (!provider.supports(toTest)) { 
    				continue;
    			}
    			if (debug) { 
    				logger.debug("Authentication attempt using "
    						+ provider.getClass().getName());
    			}
    			try { 
                    // 3、认证操作
    				result = provider.authenticate(authentication);
    
    				if (result != null) { 
    					copyDetails(authentication, result);
    					break;
    				}
    			}
    			catch (AccountStatusException | InternalAuthenticationServiceException e) { 
    				prepareException(e, authentication);
    				// SEC-546: Avoid polling additional providers if auth failure is due to
    				// invalid account status
    				throw e;
    			} catch (AuthenticationException e) { 
    				lastException = e;
    			}
    		}
    		if (result == null && parent != null) { 
    			// Allow the parent to try.
    			try { 
                    //4、上述认证失败后，用父级的认证器做认证
    				result = parentResult = 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 = parentException = e;
    			}
    		}
        	//5、认证成功后返回
    		if (result != null) { 
    			if (eraseCredentialsAfterAuthentication
    					&& (result instanceof CredentialsContainer)) { 
    				// Authentication is complete. Remove credentials and other secret data
    				// from authentication
    				((CredentialsContainer) result).eraseCredentials();
    			}
    			// If the parent AuthenticationManager was attempted and successful then it will publish an AuthenticationSuccessEvent
    			// This check prevents a duplicate AuthenticationSuccessEvent if the parent AuthenticationManager already published it
    			if (parentResult == null) { 
    				eventPublisher.publishAuthenticationSuccess(result);
    			}
    			return result;
    		}
        	//6、认证失败后，返回异常信息
    		// 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}"));
    		}
    		// If the parent AuthenticationManager was attempted and failed then it will publish an AbstractAuthenticationFailureEvent
    		// This check prevents a duplicate AbstractAuthenticationFailureEvent if the parent AuthenticationManager already published it
    		if (parentException == null) { 
    			prepareException(lastException, authentication);
    		}
    		throw lastException;
    	}

这里主要说下1、2、3个步骤，认证成功后，认证就通过了，认证失败了，后面的父级验证，基本上也会成功；

首先是认证管理器，负责管理多个认证的提供者，认证的提供者，主要认证两个地方

public interface AuthenticationProvider { 
    	//3、拿到需要认证的信息`Authentication authentication`后，进行认证操作；
    	Authentication authenticate(Authentication authentication)
    			throws AuthenticationException;
    	//2、认证的类型是不是匹配的，例如：帐号密码登录、手机号+验证码登录、扫码登录等
    	boolean supports(Class<?> authentication);
    }

如图所示：

![87fbb39f8dd493262ec93d51aeef1470.png][]

我们使用的是默认的认证提供者是`org.springframework.security.authentication.dao.DaoAuthenticationProvider`,我就主要看这个默认的提供者；两个步骤的实现 方法，其实都是在抽象类中实现`org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider`,下面，我们就直接看这个抽象类的两个接口实现：

##### 2.2.1、先看第二个步骤：认证的类型是不是匹配的，例如：帐号密码登录、手机号+验证码登录、扫码登录等 #####

public boolean supports(Class<?> authentication) {
    		return (UsernamePasswordAuthenticationToken.class
    				.isAssignableFrom(authentication));
    	}

可以看到，判断的类型是`UsernamePasswordAuthenticationToken.class`,在上一个小节，**2.1节中**

`UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken( username, password);`确实是同一个类型；

##### 2.2.2、第三个步骤：拿到需要认证的信息`Authentication authentication`后，进行认证操作； #####

public Authentication authenticate(Authentication authentication)
    			throws AuthenticationException { 
    		Assert.isInstanceOf(UsernamePasswordAuthenticationToken.class, authentication,
    				() -> messages.getMessage(
    						"AbstractUserDetailsAuthenticationProvider.onlySupports",
    						"Only UsernamePasswordAuthenticationToken is supported"));
    
    		// Determine username 1、拿到当前登录的用户名
    		String username = (authentication.getPrincipal() == null) ? "NONE_PROVIDED"
    				: authentication.getName();
    
    		boolean cacheWasUsed = true;
        	// 2、从缓存中，拿到用户明细信息，很明显，拿不到，略过
    		UserDetails user = this.userCache.getUserFromCache(username);
    
    		if (user == null) { 
    			cacheWasUsed = false;
    
    			try { 
                    // 3、拿到用户的信息
    				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 { 
    			preAuthenticationChecks.check(user);
    			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;
    			}
    		}
    
    		postAuthenticationChecks.check(user);
    
    		if (!cacheWasUsed) { 
    			this.userCache.putUserInCache(user);
    		}
    
    		Object principalToReturn = user;
    
    		if (forcePrincipalAsString) { 
    			principalToReturn = user.getUsername();
    		}
    		//4、中间步骤略过，最后一步，认证成功后，返回认证成功对象
    		return createSuccessAuthentication(principalToReturn, authentication, user);
    	}

源代码，确实是篇幅过大，过多，1、2步骤，就不说了~就挑重点讲

**步骤三**，调用子类的`org.springframework.security.authentication.dao.DaoAuthenticationProvider`的`retrieveUser`方法

protected final UserDetails retrieveUser(String username,
    			UsernamePasswordAuthenticationToken authentication)
    			throws AuthenticationException { 
    		prepareTimingAttackProtection();
    		try { 
    			UserDetails loadedUser = this.getUserDetailsService().loadUserByUsername(username);
    			if (loadedUser == null) { 
    				throw new InternalAuthenticationServiceException(
    						"UserDetailsService returned null, which is an interface contract violation");
    			}
    			return loadedUser;
    		}
    		catch (UsernameNotFoundException ex) { 
    			mitigateAgainstTimingAttack(authentication);
    			throw ex;
    		}
    		catch (InternalAuthenticationServiceException ex) { 
    			throw ex;
    		}
    		catch (Exception ex) { 
    			throw new InternalAuthenticationServiceException(ex.getMessage(), ex);
    		}
    	}

只看关键的一步

UserDetails loadedUser = this.getUserDetailsService().loadUserByUsername(username);

在刚刚的验证流程中，有个接口，查询用户的明细信息

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

我们用的默认接口是`org.springframework.security.provisioning.InMemoryUserDetailsManager`;为什么是这个？

上述案例代码中，有这个的配置，不知道各位有没有映像

@Override
        protected void configure(AuthenticationManagerBuilder auth) throws Exception { 
            auth.inMemoryAuthentication().withUser("test").password(passwordEncoder().encode("123456"))
                    .authorities("admin");
        }

这个地方，拿到用户存储的帐号、密码，跟当前登录用户的帐号密码，做认证，就可以认证成功了；整个步骤，又多了一环

![8c9f479092036f4f77aff6d62d3a42fa.png][]

**步骤四**：认证成功后，返回认证成功对象

protected Authentication createSuccessAuthentication(Object principal,
    			Authentication authentication, UserDetails user) { 
    		UsernamePasswordAuthenticationToken result = new UsernamePasswordAuthenticationToken(
    				principal, authentication.getCredentials(),
    				authoritiesMapper.mapAuthorities(user.getAuthorities()));
    		result.setDetails(authentication.getDetails());
    
    		return result;
    	}

帐号密码，验证成功之后，又再次创建了`UsernamePasswordAuthenticationToken`对象，这次调用的是另外的一个构造方法（在上面2.1节中，有说明），这次是把验证信息，设置成了`true`

public UsernamePasswordAuthenticationToken(Object principal, Object credentials,
    			Collection<? extends GrantedAuthority> authorities) { 
    		super(authorities);
    		this.principal = principal;
    		this.credentials = credentials;
    		super.setAuthenticated(true); //把验证信息，设置成了`true`
    	}

至此，登录认证的源码，就已经看完了，后续还有几个步骤，虽然重要，但是也没有什么难度了；

### 3、验证成功后，存储会话信息 ###

sessionStrategy.onAuthentication(authResult, request, response);

存储会话这个，就不详细解释了，现在一般都是分布式系统，会话需要进行统一处理，在这里处理，也可以，在最终登录回调的处理器中处理，也是可以的，比较简单；

### 4、失败之后，走失败的异常处理 ###

unsuccessfulAuthentication(request, response, failed);

失败处理，也就不解释，最终会调用失败的处理器；在案例的代码中，也实际指定了处理器

### 5、是否继续链路 ###

// Authentication success
    		if (continueChainBeforeSuccessfulAuthentication) { 
    			chain.doFilter(request, response);
    		}

一般默认是不在继续链路下去的，也就是后续的拦截器，不在执行，直接返回（都登录成功了，还链路个啥？）；

### 6、登录成功后，成功处理器 ###

successfulAuthentication(request, response, chain, authResult);

登录成功后，执行的登录成功处理器，暂时不详细解释了；

## 4、总结-最终认证流程 ##

最终认证流程如图：

![5262eb3b7b21960bc7c1b613950e2583.png][]

详细的代码，可以查看[《码云》][Link 1]

[spring security]: https://docs.spring.io/spring-security/site/docs/5.4.6/reference/html5/#exploits
[Spring securty_]: https://blog.csdn.net/qq_28410283/article/details/120160356
[Spring securty_ 1]: https://blog.csdn.net/qq_28410283/article/details/120160426
[Spring securty_ 2]: https://blog.csdn.net/qq_28410283/article/details/120160473
[1.png]: /images/20210923/f331e99b9b9746cf97c138cfb2d81434.png
[f4bc567cc6d917b7a771f4aa086aaede.png]: /images/20210923/a9f39178083242e4aca8a7a584eb9218.png
[87fbb39f8dd493262ec93d51aeef1470.png]: /images/20210923/e8e1916e71ab47a8a607180065f45b80.png
[8c9f479092036f4f77aff6d62d3a42fa.png]: /images/20210923/cef17c3202f540059b24056d1ac6ee14.png
[5262eb3b7b21960bc7c1b613950e2583.png]: /images/20210923/69212bd96bd541d6996a883511155190.png
[Link 1]: https://gitee.com/liqi01/badger-spring-security