Shiro DefaultSecurityManager默认的安全管理器及认证原理

DefaultSecurityManager

DefaultSecurityManager主要实现了SecurityManager的行为login()、logout()、createSubject()

UsernamePasswordToken token = new UsernamePasswordToken("username", "password");
Subject currentUser = SecurityUtils.getSubject();
currentUser.login(token);

DelegatingSubject的login()

Subject执行认证操作（成功为Subject设置会员信息） --> SecurityManager执行认证操作（成功创建Subject） --> Realm执行认证操作（认证及匹配逻辑、将认证信息加入缓存）

public void login(AuthenticationToken token) throws AuthenticationException {
        clearRunAsIdentitiesInternal();
        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;
        }
    }

DefaultSecurityManager的login()方法

public Subject login(Subject subject, AuthenticationToken token) throws AuthenticationException {
        AuthenticationInfo info;
        try {
　　　　　　  // DefaultSecurityManager继承了AuthenticatingSecurityManager
            // AuthenticatingSecurityManager使用自己的Authenticator认证器进行会员信息认证，后文详解#1
　　　　　　　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
        }
　　　　　// 创建Subject，后文详解#2
        Subject loggedIn = createSubject(token, info, subject);
　　　　　// 启用了记住我功能时起作用
        onSuccessfulLogin(token, info, loggedIn);

        return loggedIn;
    }

书接前文#1

AuthenticatingSecurityManager使用自己的Authenticator认证器进行会员信息认证

public AuthenticatingSecurityManager() {
    super();
    this.authenticator = new ModularRealmAuthenticator();
}

public AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {
    return this.authenticator.authenticate(token);
}

AbstractAuthenticator的公共认证逻辑，相同的行为抽取到父类了

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 {
　　　　　　　 // 具体的行为抽象出来了，ModularRealmAuthenticator负责具体实现
            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);
　　　　　// 如果有AuthenticationListener的实现类起作用
        notifySuccess(token, info);

        return info;
    }

ModularRealmAuthenticator具体实现认证行为

protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken) throws AuthenticationException {
    assertRealmsConfigured();
    Collection<Realm> realms = getRealms();
    if (realms.size() == 1) {
　　　　　// 单领域认证
        return doSingleRealmAuthentication(realms.iterator().next(), authenticationToken);
    } else {
        return doMultiRealmAuthentication(realms, authenticationToken);
    }
}

单领域认证

protected AuthenticationInfo doSingleRealmAuthentication(Realm realm, AuthenticationToken token) {
    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);
    }
    // 获得认证信息的公共行为抽取出来到父类
    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;
}

AuthenticatingRealm获得认证信息的公共行为抽取出来到父类

public final AuthenticationInfo getAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
    // 开启缓存功能起作用
    AuthenticationInfo info = getCachedAuthenticationInfo(token);
    if (info == null) {
        // 具体的认证行为抽象出来让程序员去继承AuthenticatingRealm具体实现
        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) {
        // token的登录信息和数据库查询出的会员信息进行比较，后文详解#3
        assertCredentialsMatch(token, info);
    } else {
        log.debug("No AuthenticationInfo found for submitted AuthenticationToken [{}].  Returning null.", token);
    }

    return info;
}

程序员根据业务自定义的认证领域

package com.wjz.demo;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.realm.AuthenticatingRealm;

public class CustomRealm extends AuthenticatingRealm {

    @Override
    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
        return new SimpleAuthenticationInfo("wjz", "123", getName());
    }

}

书接前文#2

SecurityManager的createSubject()

protected Subject createSubject(AuthenticationToken token, AuthenticationInfo info, Subject existing) {
    SubjectContext context = createSubjectContext();
    context.setAuthenticated(true);
　　 // 设置会员的登录信息UsernamePasswordToken(username, password)类
    context.setAuthenticationToken(token);
　　 // 设置认证成功的会员信息SimpleAuthenticationInfo(principal, password, username)类
    context.setAuthenticationInfo(info);
    if (existing != null) {
        context.setSubject(existing);
    }
    return createSubject(context);
}

公共逻辑抽取出来

public Subject createSubject(SubjectContext subjectContext) {
    // 创建一个备份对象
    SubjectContext context = copy(subjectContext);

    // 确保有安全管理器
    context = ensureSecurityManager(context);

    //Resolve an associated Session (usually based on a referenced session ID), and place it in the context before
    //sending to the SubjectFactory.  The SubjectFactory should not need to know how to acquire sessions as the
    //process is often environment specific - better to shield the SF from these details:
    context = resolveSession(context);

    // 如果有必要的话从remeberme中获得会员信息
    context = resolvePrincipals(context);

    // 使用SubjectFactory创建Subject
    Subject subject = doCreateSubject(context);

    //save this subject for future reference if necessary:
    //(this is needed here in case rememberMe principals were resolved and they need to be stored in the
    //session, so we don't constantly rehydrate the rememberMe PrincipalCollection on every operation).
    //Added in 1.2:
    save(subject);

    return subject;
}

使用SubjectFactory（DefaultWebSubjectFactory）创建Subject（WebDelegatingSubject）

protected Subject doCreateSubject(SubjectContext context) {
    return getSubjectFactory().createSubject(context);
}

public Subject createSubject(SubjectContext context) {
    if (!(context instanceof WebSubjectContext)) {
        return super.createSubject(context);
    }
    WebSubjectContext wsc = (WebSubjectContext) context;
    SecurityManager securityManager = wsc.resolveSecurityManager();
    Session session = wsc.resolveSession();
    boolean sessionEnabled = wsc.isSessionCreationEnabled();
    PrincipalCollection principals = wsc.resolvePrincipals();
    boolean authenticated = wsc.resolveAuthenticated();
    String host = wsc.resolveHost();
    ServletRequest request = wsc.resolveServletRequest();
    ServletResponse response = wsc.resolveServletResponse();

    return new WebDelegatingSubject(principals, authenticated, host, session, sessionEnabled,
            request, response, securityManager);
}

DelegatingSubject执行login的逻辑

public void login(AuthenticationToken token) throws AuthenticationException {
    clearRunAsIdentitiesInternal();
　　 // 调用了上面的一整套逻辑，以下是为Subject设置信息
    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;
    }
}

书接前文#3

 获得凭证匹配器（SimpleCredentialsMatcher）进行匹配

protected void assertCredentialsMatch(AuthenticationToken token, AuthenticationInfo info) throws AuthenticationException {
    CredentialsMatcher cm = getCredentialsMatcher();
    if (cm != null) {
　　　　  // 执行匹配动作
        if (!cm.doCredentialsMatch(token, info)) {
            //not successful - throw an exception to indicate this:
            String msg = "Submitted credentials for token [" + token + "] did not match the expected credentials.";
            throw new IncorrectCredentialsException(msg);
        }
    } else {
        throw new AuthenticationException("A CredentialsMatcher must be configured in order to verify " +
                "credentials during authentication.  If you do not wish for credentials to be examined, you " +
                "can configure an " + AllowAllCredentialsMatcher.class.getName() + " instance.");
    }
}

public boolean doCredentialsMatch(AuthenticationToken token, AuthenticationInfo info) {
    Object tokenCredentials = getCredentials(token);
    Object accountCredentials = getCredentials(info);
    return equals(tokenCredentials, accountCredentials);
}

SecurityManager的logout() 

Subject执行退出操作（清空会员信息） --> SecurityManager执行退出操作（记住我退出、清空session） --> Realm执行退出操作（清空缓存如认证信息、授权信息）

Subject currentUser = SecurityUtils.getSubject();
currentUser.logout();

DelegatingSubject的logout行为，此为公共行为

public void logout() {
    try {
        clearRunAsIdentitiesInternal();
        // 核心退出功能
        this.securityManager.logout(this);
    } finally {
　　　　 // 将以下Subject的信息置为null
        this.session = null;
        this.principals = null;
        this.authenticated = false;
        //Don't set securityManager to null here - the Subject can still be
        //used, it is just considered anonymous at this point.  The SecurityManager instance is
        //necessary if the subject would log in again or acquire a new session.  This is in response to
        //https://issues.apache.org/jira/browse/JSEC-22
        //this.securityManager = null;
    }
}

安全管理器的公共退出逻辑

public void logout(Subject subject) {

    if (subject == null) {
        throw new IllegalArgumentException("Subject method argument cannot be null.");
    }
    // 记住我退出，也就是清浏览器cookie
    beforeLogout(subject);

    PrincipalCollection principals = subject.getPrincipals();
    if (principals != null && !principals.isEmpty()) {
        if (log.isDebugEnabled()) {
            log.debug("Logging out subject with primary principal {}", principals.getPrimaryPrincipal());
        }
        Authenticator authc = getAuthenticator();
        if (authc instanceof LogoutAware) {
　　　　　　　 // 认证器执行退出操作，后文详解#4
            ((LogoutAware) authc).onLogout(principals);
        }
    }

    try {
　　　　  // 清空shiro的session
        delete(subject);
    } catch (Exception e) {
        if (log.isDebugEnabled()) {
            String msg = "Unable to cleanly unbind Subject.  Ignoring (logging out).";
            log.debug(msg, e);
        }
    } finally {
        try {
            stopSession(subject);
        } catch (Exception e) {
            if (log.isDebugEnabled()) {
                String msg = "Unable to cleanly stop Session for Subject [" + subject.getPrincipal() + "] " +
                        "Ignoring (logging out).";
                log.debug(msg, e);
            }
        }
    }
}

书接前文#4

public void onLogout(PrincipalCollection principals) {
    // 如果有AuthenticationListener执行监听行为
    super.onLogout(principals);
    Collection<Realm> realms = getRealms();
    if (!CollectionUtils.isEmpty(realms)) {
        for (Realm realm : realms) {
            if (realm instanceof LogoutAware) {
                 // 领域执行退出行为
                ((LogoutAware) realm).onLogout(principals);
            }
        }
    }
}