OAuth 2.0 Resource Server Multi-tenancy

Supporting both JWT and Opaque Token

在某些情况下，您可能需要访问两种令牌。例如，您可能支持不止一个租户，其中一个租户发布 JWT，另一个发布不透明令牌。

如果必须在请求时做出此决定，那么可以通过使用 AuthenticationManagerResolver 来实现，如下所示：

Java
Kotlin

@Bean
AuthenticationManagerResolver<HttpServletRequest> tokenAuthenticationManagerResolver
        (JwtDecoder jwtDecoder, OpaqueTokenIntrospector opaqueTokenIntrospector) {
    AuthenticationManager jwt = new ProviderManager(new JwtAuthenticationProvider(jwtDecoder));
    AuthenticationManager opaqueToken = new ProviderManager(
            new OpaqueTokenAuthenticationProvider(opaqueTokenIntrospector));
    return (request) -> useJwt(request) ? jwt : opaqueToken;
}

@Bean
fun tokenAuthenticationManagerResolver
        (jwtDecoder: JwtDecoder, opaqueTokenIntrospector: OpaqueTokenIntrospector):
        AuthenticationManagerResolver<HttpServletRequest> {
    val jwt = ProviderManager(JwtAuthenticationProvider(jwtDecoder))
    val opaqueToken = ProviderManager(OpaqueTokenAuthenticationProvider(opaqueTokenIntrospector));

    return AuthenticationManagerResolver { request ->
        if (useJwt(request)) {
            jwt
        } else {
            opaqueToken
        }
    }
}

useJwt(HttpServletRequest) 的实现可能会依赖于自定义请求资料，例如路径。

然后在 DSL 中指定此 AuthenticationManagerResolver：

Authentication Manager Resolver

Java
Kotlin
Xml

http
    .authorizeHttpRequests(authorize -> authorize
        .anyRequest().authenticated()
    )
    .oauth2ResourceServer(oauth2 -> oauth2
        .authenticationManagerResolver(this.tokenAuthenticationManagerResolver)
    );

http {
    authorizeRequests {
        authorize(anyRequest, authenticated)
    }
    oauth2ResourceServer {
        authenticationManagerResolver = tokenAuthenticationManagerResolver()
    }
}

<http>
    <oauth2-resource-server authentication-manager-resolver-ref="tokenAuthenticationManagerResolver"/>
</http>

Multi-tenancy

当验证 bearer token 有多种策略（以某种租户标识符为键）时，资源服务器被认为是多租户。

例如，您的资源服务器可能接受来自两个不同授权服务器的 bearer token。或者，您的授权服务器可能表示多个颁发者。

在每种情况下，都需要做两件事，并权衡执行方式。

Resolve the tenant
Propagate the tenant

Resolving the Tenant By Claim

区分租户的一种方法是通过 issuers 声明。由于 issuers 声明附带签名 JWT，因此可以使用 JwtIssuerAuthenticationManagerResolver 完成此操作，如下所示：

Multi-tenancy Tenant by JWT Claim

Java
Kotlin
Xml

JwtIssuerAuthenticationManagerResolver authenticationManagerResolver = JwtIssuerAuthenticationManagerResolver
    .fromTrustedIssuers("https://idp.example.org/issuerOne", "https://idp.example.org/issuerTwo");

http
    .authorizeHttpRequests(authorize -> authorize
        .anyRequest().authenticated()
    )
    .oauth2ResourceServer(oauth2 -> oauth2
        .authenticationManagerResolver(authenticationManagerResolver)
    );

val customAuthenticationManagerResolver = JwtIssuerAuthenticationManagerResolver
    .fromTrustedIssuers("https://idp.example.org/issuerOne", "https://idp.example.org/issuerTwo")
http {
    authorizeRequests {
        authorize(anyRequest, authenticated)
    }
    oauth2ResourceServer {
        authenticationManagerResolver = customAuthenticationManagerResolver
    }
}

<http>
    <oauth2-resource-server authentication-manager-resolver-ref="authenticationManagerResolver"/>
</http>

<bean id="authenticationManagerResolver"
        class="org.springframework.security.oauth2.server.resource.authentication.JwtIssuerAuthenticationManagerResolver">
    <constructor-arg>
        <list>
            <value>https://idp.example.org/issuerOne</value>
            <value>https://idp.example.org/issuerTwo</value>
        </list>
    </constructor-arg>
</bean>

这很好，因为 issuers 端点是延迟加载的。实际上，仅在发送具有对应 issuers 的第一个请求时才会实例化相应的 JwtAuthenticationProvider。这允许应用程序启动独立于授权服务器的启动和可用性。

Dynamic Tenants

当然，您可能不希望每次添加新租户时都重新启动应用程序。在这种情况下，您可以使用 AuthenticationManager 实例的存储库配置 JwtIssuerAuthenticationManagerResolver，您可以在运行时编辑它，如下所示：

Java
Kotlin

private void addManager(Map<String, AuthenticationManager> authenticationManagers, String issuer) {
	JwtAuthenticationProvider authenticationProvider = new JwtAuthenticationProvider
	        (JwtDecoders.fromIssuerLocation(issuer));
	authenticationManagers.put(issuer, authenticationProvider::authenticate);
}

// ...

JwtIssuerAuthenticationManagerResolver authenticationManagerResolver =
        new JwtIssuerAuthenticationManagerResolver(authenticationManagers::get);

http
    .authorizeHttpRequests(authorize -> authorize
        .anyRequest().authenticated()
    )
    .oauth2ResourceServer(oauth2 -> oauth2
        .authenticationManagerResolver(authenticationManagerResolver)
    );

private fun addManager(authenticationManagers: MutableMap<String, AuthenticationManager>, issuer: String) {
    val authenticationProvider = JwtAuthenticationProvider(JwtDecoders.fromIssuerLocation(issuer))
    authenticationManagers[issuer] = AuthenticationManager {
        authentication: Authentication? -> authenticationProvider.authenticate(authentication)
    }
}

// ...

val customAuthenticationManagerResolver: JwtIssuerAuthenticationManagerResolver =
    JwtIssuerAuthenticationManagerResolver(authenticationManagers::get)
http {
    authorizeRequests {
        authorize(anyRequest, authenticated)
    }
    oauth2ResourceServer {
        authenticationManagerResolver = customAuthenticationManagerResolver
    }
}

在这种情况下，你要使用一种策略构建 JwtIssuerAuthenticationManagerResolver，以便给定发行人获取 AuthenticationManager。这种方法允许我们添加和从存储库中移除元素（在代码片段中显示为 Map），而且是在运行时。

简单获取任何颁发者并从中构造 AuthenticationManager 并不安全。颁发者应该是代码可以从受信任来源（例如允许的颁发者列表）验证的一个。

Parsing the Claim Only Once

您可能已经观察到，尽管此策略很简单，但其权衡是 JWT 由 AuthenticationManagerResolver 解析一次，然后在请求中随后由 JwtDecoder 再次解析。

可以通过直接使用 Nimbus 中的 JWTClaimsSetAwareJWSKeySelector 配置 JwtDecoder 来缓解这种额外的解析：

Java
Kotlin

@Component
public class TenantJWSKeySelector
    implements JWTClaimsSetAwareJWSKeySelector<SecurityContext> {

	private final TenantRepository tenants; 1
	private final Map<String, JWSKeySelector<SecurityContext>> selectors = new ConcurrentHashMap<>(); 2

	public TenantJWSKeySelector(TenantRepository tenants) {
		this.tenants = tenants;
	}

	@Override
	public List<? extends Key> selectKeys(JWSHeader jwsHeader, JWTClaimsSet jwtClaimsSet, SecurityContext securityContext)
			throws KeySourceException {
		return this.selectors.computeIfAbsent(toTenant(jwtClaimsSet), this::fromTenant)
				.selectJWSKeys(jwsHeader, securityContext);
	}

	private String toTenant(JWTClaimsSet claimSet) {
		return (String) claimSet.getClaim("iss");
	}

	private JWSKeySelector<SecurityContext> fromTenant(String tenant) {
		return Optional.ofNullable(this.tenants.findById(tenant)) 3
		        .map(t -> t.getAttrbute("jwks_uri"))
				.map(this::fromUri)
				.orElseThrow(() -> new IllegalArgumentException("unknown tenant"));
	}

	private JWSKeySelector<SecurityContext> fromUri(String uri) {
		try {
			return JWSAlgorithmFamilyJWSKeySelector.fromJWKSetURL(new URL(uri)); 4
		} catch (Exception ex) {
			throw new IllegalArgumentException(ex);
		}
	}
}

@Component
class TenantJWSKeySelector(tenants: TenantRepository) : JWTClaimsSetAwareJWSKeySelector<SecurityContext> {
    private val tenants: TenantRepository 1
    private val selectors: MutableMap<String, JWSKeySelector<SecurityContext>> = ConcurrentHashMap() 2

    init {
        this.tenants = tenants
    }

    fun selectKeys(jwsHeader: JWSHeader?, jwtClaimsSet: JWTClaimsSet, securityContext: SecurityContext): List<Key?> {
        return selectors.computeIfAbsent(toTenant(jwtClaimsSet)) { tenant: String -> fromTenant(tenant) }
                .selectJWSKeys(jwsHeader, securityContext)
    }

    private fun toTenant(claimSet: JWTClaimsSet): String {
        return claimSet.getClaim("iss") as String
    }

    private fun fromTenant(tenant: String): JWSKeySelector<SecurityContext> {
        return Optional.ofNullable(this.tenants.findById(tenant)) 3
                .map { t -> t.getAttrbute("jwks_uri") }
                .map { uri: String -> fromUri(uri) }
                .orElseThrow { IllegalArgumentException("unknown tenant") }
    }

    private fun fromUri(uri: String): JWSKeySelector<SecurityContext?> {
        return try {
            JWSAlgorithmFamilyJWSKeySelector.fromJWKSetURL(URL(uri)) 4
        } catch (ex: Exception) {
            throw IllegalArgumentException(ex)
        }
    }
}

1	可能的租户信息源
2	`JWKKeySelector` 的一个缓存，按租户标识符归
3	查找租户比实时计算 JWK 集合端点更加安全 - 查找充当已允许租户的列表
4	通过从 JWK 集终结点返回的密钥类型来创建 `JWSKeySelector`- 这里的惰性查找意味着无需在启动时配置所有租户

以上键选择器是由多个键选择器组成的。它根据 JWT 中的 iss 声明选择要使用的键选择器。

要使用此方法，请确保授权服务器配置为将声明集包含在令牌签名中。如果没有这一点，你就无法保证颁发者没有被恶意行为者更改。

接下来，我们可以构建一个 JWTProcessor：

Java
Kotlin

@Bean
JWTProcessor jwtProcessor(JWTClaimSetJWSKeySelector keySelector) {
	ConfigurableJWTProcessor<SecurityContext> jwtProcessor =
            new DefaultJWTProcessor();
	jwtProcessor.setJWTClaimSetJWSKeySelector(keySelector);
	return jwtProcessor;
}

@Bean
fun jwtProcessor(keySelector: JWTClaimsSetAwareJWSKeySelector<SecurityContext>): JWTProcessor<SecurityContext> {
    val jwtProcessor = DefaultJWTProcessor<SecurityContext>()
    jwtProcessor.jwtClaimsSetAwareJWSKeySelector = keySelector
    return jwtProcessor
}

正如您已看到的，将租户感知下沉到这一层级的权衡在于更多配置。我们只需再进行一些配置。

接下来，我们仍希望确保您在验证发件人。但是，由于每个 JWT 的发件人可能不同，因此您还需要一个基于租户的验证器：

Java
Kotlin

@Component
public class TenantJwtIssuerValidator implements OAuth2TokenValidator<Jwt> {
    private final TenantRepository tenants;

    private final OAuth2Error error = new OAuth2Error(OAuth2ErrorCodes.INVALID_TOKEN, "The iss claim is not valid",
            "https://tools.ietf.org/html/rfc6750#section-3.1");

    public TenantJwtIssuerValidator(TenantRepository tenants) {
        this.tenants = tenants;
    }

    @Override
    public OAuth2TokenValidatorResult validate(Jwt token) {
        if(this.tenants.findById(token.getIssuer()) != null) {
            return OAuth2TokenValidatorResult.success();
        }
        return OAuth2TokenValidatorResult.failure(this.error);
    }
}

@Component
class TenantJwtIssuerValidator(private val tenants: TenantRepository) : OAuth2TokenValidator<Jwt> {
    private val error: OAuth2Error = OAuth2Error(OAuth2ErrorCodes.INVALID_TOKEN, "The iss claim is not valid",
            "https://tools.ietf.org/html/rfc6750#section-3.1")

    override fun validate(token: Jwt): OAuth2TokenValidatorResult {
        return if (tenants.findById(token.issuer) != null)
            OAuth2TokenValidatorResult.success() else OAuth2TokenValidatorResult.failure(error)
    }
}

现在我们有了 tenant-aware 处理器和 tenant-aware 验证器，我们可以继续创建我们的 JwtDecoder：

Java
Kotlin

@Bean
JwtDecoder jwtDecoder(JWTProcessor jwtProcessor, OAuth2TokenValidator<Jwt> jwtValidator) {
	NimbusJwtDecoder decoder = new NimbusJwtDecoder(processor);
	OAuth2TokenValidator<Jwt> validator = new DelegatingOAuth2TokenValidator<>
			(JwtValidators.createDefault(), jwtValidator);
	decoder.setJwtValidator(validator);
	return decoder;
}

@Bean
fun jwtDecoder(jwtProcessor: JWTProcessor<SecurityContext>?, jwtValidator: OAuth2TokenValidator<Jwt>?): JwtDecoder {
    val decoder = NimbusJwtDecoder(jwtProcessor)
    val validator: OAuth2TokenValidator<Jwt> = DelegatingOAuth2TokenValidator(JwtValidators.createDefault(), jwtValidator)
    decoder.setJwtValidator(validator)
    return decoder
}

我们已完成对租户解析的讨论。

如果您选择按 JWT 声明之外的内容解析租户，则需要确保在相同的方式中解决下游资源服务器。例如，如果您按子域解析，则您可能需要使用相同子域解决下游资源服务器。

但是，如果您通过持有者令牌中声明的内容解决它，请继续阅读以了解 Spring Security’s support for bearer token propagation。