shiro身份认证流程

Shiro身份认证流程

身份认证：身份认证主要验证用户的身份，即验证用户操作时是其本人操作的，一般通过验证用户唯一principals和credentials，其中principals代表用户的身份，可以用用户名，邮箱，手机号等标识，唯一即可。credentials代表用户的证明/凭证，我们一般称之为密码。

认证流程源码执行过程

详细代码参考，本示例代码为shiro官网的示例代码

log.info("My First Apache Shiro Application");

Factory<SecurityManager> factory = new IniSecurityManagerFactory("classpath:shiro.ini");
SecurityManager securityManager = factory.getInstance();
SecurityUtils.setSecurityManager(securityManager);

// get the currently executing user:
Subject currentUser = SecurityUtils.getSubject();

// Do some stuff with a Session (no need for a web or EJB container!!!)
Session session = currentUser.getSession();
session.setAttribute("someKey", "aValue");
String value = (String) session.getAttribute("someKey");
if (value.equals("aValue")) {
    log.info("Retrieved the correct value! [" + value + "]");
}

// let's login the current user so we can check against roles and permissions:
if (!currentUser.isAuthenticated()) {
    UsernamePasswordToken token = new UsernamePasswordToken("lonestarr", "vespa");
    token.setRememberMe(true);
    try {
        currentUser.login(token);
    } catch (UnknownAccountException uae) {
        log.info("There is no user with username of " + token.getPrincipal());
    } catch (IncorrectCredentialsException ice) {
        log.info("Password for account " + token.getPrincipal() + " was incorrect!");
    } catch (LockedAccountException lae) {
        log.info("The account for username " + token.getPrincipal() + " is locked.  " +
                "Please contact your administrator to unlock it.");
    }
    // ... catch more exceptions here (maybe custom ones specific to your application?
    catch (AuthenticationException ae) {
        //unexpected condition?  error?
    }
}

首先通过SecurityUtils获取当前的主体，然后通过UsernamePasswordToken封装当前用户的账号和密码，然后通过Subject进行登录认证。

Subject.login会调用Subject的唯一实现类DelegatingSubject去进行登录，其会自动委托给Security Manager，调用之前必须通过SecurityUtils. setSecurityManager()设置,详情查看下面代码

public void login(AuthenticationToken token) throws AuthenticationException {
    //主要为清除session
    clearRunAsIdentitiesInternal();
    //委托给securityManager进行登录
    Subject subject = securityManager.login(this, token);

    PrincipalCollection principals;

    String host = null;

    if (subject instanceof DelegatingSubject) {
        DelegatingSubject delegating = (DelegatingSubject) subject;
        //we have to do this in case there are assumed identities - we don't want to lose the 'real' principals:
        principals = delegating.principals;
        host = delegating.host;
    } else {
        principals = subject.getPrincipals();
    }

    if (principals == null || principals.isEmpty()) {
        String msg = "Principals returned from securityManager.login( token ) returned a null or " +
                "empty value.  This value must be non null and populated with one or more elements.";
        throw new IllegalStateException(msg);
    }
    this.principals = principals;
    this.authenticated = true;
    if (token instanceof HostAuthenticationToken) {
        host = ((HostAuthenticationToken) token).getHost();
    }
    if (host != null) {
        this.host = host;
    }
    Session session = subject.getSession(false);
    if (session != null) {
        this.session = decorate(session);
    } else {
        this.session = null;
    }
}

securityManager会交给DefaultSeurityManager去进行登录，登录成功之后返回相应的Subject

public Subject login(Subject subject, AuthenticationToken token) throws AuthenticationException {
    AuthenticationInfo info;
    try {
        //验证token
        info = authenticate(token);
    } catch (AuthenticationException ae) {
        try {
            onFailedLogin(token, ae, subject);
        } catch (Exception e) {
            if (log.isInfoEnabled()) {
                log.info("onFailedLogin method threw an " +
                        "exception.  Logging and propagating original AuthenticationException.", e);
            }
        }
        throw ae; //propagate
    }

    Subject loggedIn = createSubject(token, info, subject);

    onSuccessfulLogin(token, info, loggedIn);

    return loggedIn;
}

上面流程中authenticate最终调用Authenticator去验证用户的身份信息，默认调用的是AbstractAuthenticator的authenticate方法

public final AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {

    if (token == null) {
        throw new IllegalArgumentException("Method argument (authentication token) cannot be null.");
    }

    log.trace("Authentication attempt received for token [{}]", token);

    AuthenticationInfo info;
    try {
        info = doAuthenticate(token);
        if (info == null) {
            String msg = "No account information found for authentication token [" + token + "] by this " +
                    "Authenticator instance.  Please check that it is configured correctly.";
            throw new AuthenticationException(msg);
        }
    } catch (Throwable t) {
        AuthenticationException ae = null;
        if (t instanceof AuthenticationException) {
            ae = (AuthenticationException) t;
        }
        if (ae == null) {
            //Exception thrown was not an expected AuthenticationException.  Therefore it is probably a little more
            //severe or unexpected.  So, wrap in an AuthenticationException, log to warn, and propagate:
            String msg = "Authentication failed for token submission [" + token + "].  Possible unexpected " +
                    "error? (Typical or expected login exceptions should extend from AuthenticationException).";
            ae = new AuthenticationException(msg, t);
            if (log.isWarnEnabled())
                log.warn(msg, t);
        }
        try {
            notifyFailure(token, ae);
        } catch (Throwable t2) {
            if (log.isWarnEnabled()) {
                String msg = "Unable to send notification for failed authentication attempt - listener error?.  " +
                        "Please check your AuthenticationListener implementation(s).  Logging sending exception " +
                        "and propagating original AuthenticationException instead...";
                log.warn(msg, t2);
            }
        }


        throw ae;
    }

    log.debug("Authentication successful for token [{}].  Returned account [{}]", token, info);

    notifySuccess(token, info);

    return info;
}

身份验证的方法最终调用的是ModularRealmAuthenticator的doAuthenticate方法，根据获取到的realms进行真正的身份认证

protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken) throws AuthenticationException {
    //判断是否进行Realms配置，如果没有直接会抛出异常
    assertRealmsConfigured();
    //获取相关realms集合
    Collection<Realm> realms = getRealms();
    //根据realms的数量进行响应的操作
    if (realms.size() == 1) {
        //进行身份认证
        return doSingleRealmAuthentication(realms.iterator().next(), authenticationToken);
    } else {
        return doMultiRealmAuthentication(realms, authenticationToken);
    }
}
	//Authenticator会把相应的token传入Realm，从Realm获取身份验证信息，如果没有返回/抛出异常表示身份验证失败了。此处可以配置多个Realm，将按照相应的顺序及策略进行访问。
    protected AuthenticationInfo doSingleRealmAuthentication(Realm realm, AuthenticationToken token) {
          //判断该realm是否支持该token的验证
        if (!realm.supports(token)) {
            String msg = "Realm [" + realm + "] does not support authentication token [" +
                    token + "].  Please ensure that the appropriate Realm implementation is " +
                    "configured correctly or that the realm accepts AuthenticationTokens of this type.";
            throw new UnsupportedTokenException(msg);
        }
        //根据主体的唯一查询出该用户
        AuthenticationInfo info = realm.getAuthenticationInfo(token);
        if (info == null) {
            String msg = "Realm [" + realm + "] was unable to find account data for the " +
                    "submitted AuthenticationToken [" + token + "].";
            throw new UnknownAccountException(msg);
        }
        return info;
    }

realm进行身份认证，默认调用的是AuthenticatingRealm的getAuthenticationInfo进行身份与凭证的验证

public final AuthenticationInfo getAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
    //如果配置了缓存，则从缓存中获取AuthenticationInfo，即AuthenticationInfo中封装了用户的身份和凭证信息
    AuthenticationInfo info = getCachedAuthenticationInfo(token);
    if (info == null) {
        //otherwise not cached, perform the lookup:
        //缓存中没有，则调用该方法获取AuthenticationInfo
        info = doGetAuthenticationInfo(token);
        log.debug("Looked up AuthenticationInfo [{}] from doGetAuthenticationInfo", info);
        if (token != null && info != null) {
            cacheAuthenticationInfoIfPossible(token, info);
        }
    } else {
        log.debug("Using cached authentication info [{}] to perform credentials matching.", info);
    }

    if (info != null) {
        //对用户的凭证进行校验，即密码
        assertCredentialsMatch(token, info);
    } else {
        log.debug("No AuthenticationInfo found for submitted AuthenticationToken [{}].  Returning null.", token);
    }

    return info;
}

身份认证流程总结

1、首先调用Subject.login(token)进行登录，其会自动委托给Security Manager，调用之前必须通过SecurityUtils. setSecurityManager()设置；

2、SecurityManager负责真正的身份验证逻辑；它会委托给Authenticator进行身份验证；

3、Authenticator才是真正的身份验证者，Shiro API中核心的身份认证入口点，此处可以自定义插入自己的实现；

4、Authenticator可能会委托给相应的AuthenticationStrategy进行多Realm身份验证，默认ModularRealmAuthenticator会调用AuthenticationStrategy进行多Realm身份验证；

5、Authenticator会把相应的token传入Realm，从Realm获取身份验证信息，如果没有返回/抛出异常表示身份验证失败了。此处可以配置多个Realm，将按照相应的顺序及策略进行访问

示例代码：

参考：

官网参考

跟我学shiro### Shiro身份认证流程