shiro认证过程分析
作者：互联网
0前言
shiro身份认证过程可以从subject.login(token)开始梳理。
本节只分析基础的认证流程，认证过程的各种策略（authenticationStrategy）、以及realm的credentialsMatcher等扩展内容不是本节重点，感兴趣的童鞋可以自行分析。
首先准备了测试demo：
@Test
public void testCustomRealm() {
//创建SecurityManager实例，配置realm
org.apache.shiro.mgt.SecurityManager securityManager = new DefaultSecurityManager();
Realm realm = new MyRealm1();
((DefaultSecurityManager) securityManager).setRealm(realm);
//绑定SecurityManager给SecurityUtils
SecurityUtils.setSecurityManager(securityManager);
//得到Subject
Subject subject = SecurityUtils.getSubject();
//创建用户名/密码身份验证Token（即用户身份/凭证）
UsernamePasswordToken token = new UsernamePasswordToken("test", "123");
try {
//登录，即身份验证（分析入口）
subject.login(token);
} catch (AuthenticationException e) {
//身份验证失败处理
e.printStackTrace();
}
//断言用户已经登录
Assert.assertEquals(true, subject.isAuthenticated());
//退出
subject.logout();
}
测试程序创建一个SecurityManager，为其配置了realm，并将SecurityManager绑定到SecurityUtils，SecurityUtils是全局唯一的，可以用来获取当前访问的的subject。然后创建了一个token，用subject模拟了一次登录，也就是调用login方法。Myrealm1定义如下：
public class MyRealm1 implements AuthenticatingRealm {
@Override
public String getName() {
return "myrealm1";
}
@Override
public boolean supports(AuthenticationToken token) {
return token instanceof UsernamePasswordToken; //仅支持UsernamePasswordToken类型的Token
}
@Override
public AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
String username = (String)token.getPrincipal(); //得到用户名
String password = new String((char[])token.getCredentials()); //得到密码
if(!"test".equals(username)) {
throw new UnknownAccountException(); //如果用户名错误
}
if(!"123".equals(password)) {
throw new IncorrectCredentialsException(); //如果密码错误
}
//如果身份认证验证成功，返回一个AuthenticationInfo实现；
return new SimpleAuthenticationInfo(username, password, getName());
}
}
这里Myrealm1实现了用于认证的AuthenticatingRealm 接口，实际使用一般实现Realm的子接口AuthorizingRealm（包含认证和授权的相关方法）
1认证分析
subject实现类DelegatingSubject的login方法（DelegatingSubject源码254行）
public void login(AuthenticationToken token) throws AuthenticationException {
clearRunAsIdentitiesInternal();
Subject subject = securityManager.login(this, token);
//省略其他内容...
}
DelegatingSubject调用securityManager（DefaultSecurityManager）的login来认证。
//DefaultSecurityManager源码267行
public Subject login(Subject subject, AuthenticationToken token) throws AuthenticationException {
AuthenticationInfo info;
try {
//调用父类AuthenticatingSecurityManager的authenticate
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;
}
//AuthenticatingSecurityManager源码105行
public AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {
//通过认证器Authenticator认证
return this.authenticator.authenticate(token); }
//AbstractAuthenticator第188行
public final AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {
if (token == null) {
throw new IllegalArgumentException("Method argumet (authentication token) cannot be null.");
}
log.trace("Authentication attempt received for token [{}]", token);
AuthenticationInfo info;
try {
//子类ModularRealmAuthenticator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);
}
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;
}
//ModularRealmAuthenticator 第263行
protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken) throws AuthenticationException {
assertRealmsConfigured();
Collection<Realm> realms = getRealms();
//按照单个realm和多个realm分别执行不同的处理逻辑
if (realms.size() == 1) {
return doSingleRealmAuthentication(realms.iterator().next(), authenticationToken);
} else {
return doMultiRealmAuthentication(realms, authenticationToken);
}
}
接下来处理单个realm的认证情况
//ModularRealmAuthenticator 第173行
protected AuthenticationInfo doSingleRealmAuthentication(Realm realm, AuthenticationToken token) {
//调用realm的实现方法supports判断是否支持的token类型
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);
}
//AuthenticatingRealm的getAuthenticationInfo方法
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第563行
public final AuthenticationInfo getAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
//先看看cache里面有没有
AuthenticationInfo info = getCachedAuthenticationInfo(token);
if (info == null) {
//otherwise not cached, perform the lookup:
//这里调用自定义realm实现的方法（本文开头的MyRealm1）
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) {
//这个用到了CredentialsMatch功能
assertCredentialsMatch(token, info);
} else {
log.debug("No AuthenticationInfo found for submitted AuthenticationToken [{}]. Returning null.", token);
}
return info;
}
MyRealm1的doGetAuthenticationInfo方法会通过用户名返回提前保存的用户信息info（一般可以从数据库里读取，包括用户名、加密过的密码和salt等）。
CredentialsMatch用于将输入的token密码通过配置的加密算法和用户info中的salt进行加密后于用户的加密密码匹配。（本文的MyRealm1示例没有体现这个加密功能，直接拿密码对比，失败抛异常）
如果匹配成功会返回info信息，否则会抛出认证失败相关异常。单个realm认真流程大致已经完成，下面的多realm认证流程
//ModularRealmAuthenticator 第198行
protected AuthenticationInfo doMultiRealmAuthentication(Collection<Realm> realms, AuthenticationToken token) {
AuthenticationStrategy strategy = getAuthenticationStrategy();
AuthenticationInfo aggregate = strategy.beforeAllAttempts(realms, token);
if (log.isTraceEnabled()) {
log.trace("Iterating through {} realms for PAM authentication", realms.size());
}
for (Realm realm : realms) {
aggregate = strategy.beforeAttempt(realm, token, aggregate);
if (realm.supports(token)) {
log.trace("Attempting to authenticate token [{}] using realm [{}]", token, realm);
AuthenticationInfo info = null;
Throwable t = null;
try {
info = realm.getAuthenticationInfo(token);
} catch (Throwable throwable) {
t = throwable;
if (log.isDebugEnabled()) {
String msg = "Realm [" + realm + "] threw an exception during a multi-realm authentication attempt:";
log.debug(msg, t);
}
}
aggregate = strategy.afterAttempt(realm, token, info, aggregate, t);
} else {
log.debug("Realm [{}] does not support token {}. Skipping realm.", realm, token);
}
}
aggregate = strategy.afterAllAttempts(token, aggregate);
return aggregate;
}
多realm认证流程会在循环调用每个realm的前后加入AuthenticationStrategy 策略，shiro提供了三种策略
AtLeastOneSuccessfulStrategy：有一个realm认证成功就成功
AllSuccessfulStrategy：所有的realm认证成功才成功
FirstSuccessfulStrategy：只有第一个realm认证成功才会成功
以上三种策略不满足的话，用户可以定义实现AuthenticationStrategy 进行扩展。
总结一下认证流程
（1）subject.login(token) 开始认证
（2）subject会调用SecuretyManager的login(token)方法
（3）SecurityManager调用认证器Authenticator的authenticate（token）
（4）Authenticator分单realm和多realm，多realm根据不同的AuthenticationStrategy 进行认证流程
（5）最终是调用Realm的doGetAuthenticationInfo获取info信息，然后通过CredentialsMatch进行密码比较，认证失败会抛出异常
标签：分析,info,realm,认证,token,AuthenticationException,AuthenticationInfo,shiro 来源： https://www.cnblogs.com/ouym/p/15617188.html