Authenticating `<saml2:Response>`s

为了验证 SAML 2.0 响应，Spring Security 使用 Saml2AuthenticationTokenConverter 填充 Authentication 请求，并使用 OpenSaml4AuthenticationProvider 进行身份验证。可以通过多种方式对其进行配置，包括：

改变 `RelyingPartyRegistration`被查找的方式
对时间戳验证设置时钟偏移
将响应映射到 `GrantedAuthority`实例列表
自定义用于验证声明的策略
自定义用于解密响应和声明元素的策略

要配置这些，您需要在 DSL 中使用 saml2Login#authenticationManager 方法。

Changing the SAML Response Processing Endpoint

默认端点是 /login/saml2/sso/{registrationId}。可以在 DSL 和关联元数据中对其进行更改，如下所示：

Java
Kotlin

@Bean
SecurityFilterChain securityFilters(HttpSecurity http) throws Exception {
	http
        // ...
        .saml2Login((saml2) -> saml2.loginProcessingUrl("/saml2/login/sso"))
        // ...

    return http.build();
}

@Bean
fun securityFilters(val http: HttpSecurity): SecurityFilterChain {
	http {
        // ...
        .saml2Login {
            loginProcessingUrl = "/saml2/login/sso"
        }
        // ...
    }

    return http.build()
}

及：

Java
Kotlin

relyingPartyRegistrationBuilder.assertionConsumerServiceLocation("/saml/SSO")

relyingPartyRegistrationBuilder.assertionConsumerServiceLocation("/saml/SSO")

Changing `RelyingPartyRegistration` lookup

默认情况下，此转换器将与任何关联的 <saml2:AuthnRequest> 或在 URL 中找到的任何 registrationId 进行匹配。或者，如果在这些情况下找不到，则尝试通过 <saml2:Response#Issuer> 元素查找它。

在很多情况下，您可能需要更复杂的内容，例如在支持 ARTIFACT 绑定时。在这些情况下，可以通过自定义 AuthenticationConverter 来自定义查找，可以对其进行如下自定义：

Java
Kotlin

@Bean
SecurityFilterChain securityFilters(HttpSecurity http, AuthenticationConverter authenticationConverter) throws Exception {
	http
        // ...
        .saml2Login((saml2) -> saml2.authenticationConverter(authenticationConverter))
        // ...

    return http.build();
}

@Bean
fun securityFilters(val http: HttpSecurity, val converter: AuthenticationConverter): SecurityFilterChain {
	http {
        // ...
        .saml2Login {
            authenticationConverter = converter
        }
        // ...
    }

    return http.build()
}

Setting a Clock Skew

声明方和依赖方的时间钟不完全同步并不少见。因此，您可以使用一定的容差来配置“OpenSaml4AuthenticationProvider”的默认断言验证器：

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        OpenSaml4AuthenticationProvider authenticationProvider = new OpenSaml4AuthenticationProvider();
        authenticationProvider.setAssertionValidator(OpenSaml4AuthenticationProvider
                .createDefaultAssertionValidator(assertionToken -> {
                    Map<String, Object> params = new HashMap<>();
                    params.put(CLOCK_SKEW, Duration.ofMinutes(10).toMillis());
                    // ... other validation parameters
                    return new ValidationContext(params);
                })
        );

        http
            .authorizeHttpRequests(authz -> authz
                .anyRequest().authenticated()
            )
            .saml2Login(saml2 -> saml2
                .authenticationManager(new ProviderManager(authenticationProvider))
            );
        return http.build();
    }
}

@Configuration
@EnableWebSecurity
open class SecurityConfig {
    @Bean
    open fun filterChain(http: HttpSecurity): SecurityFilterChain {
        val authenticationProvider = OpenSaml4AuthenticationProvider()
        authenticationProvider.setAssertionValidator(
            OpenSaml4AuthenticationProvider
                .createDefaultAssertionValidator(Converter<OpenSaml4AuthenticationProvider.AssertionToken, ValidationContext> {
                    val params: MutableMap<String, Any> = HashMap()
                    params[CLOCK_SKEW] =
                        Duration.ofMinutes(10).toMillis()
                    ValidationContext(params)
                })
        )
        http {
            authorizeRequests {
                authorize(anyRequest, authenticated)
            }
            saml2Login {
                authenticationManager = ProviderManager(authenticationProvider)
            }
        }
        return http.build()
    }
}

Coordinating with a `UserDetailsService`

或者，您可能希望包含来自旧版的 UserDetailsService 的用户信息。在这种情况下，响应身份验证转换器会派上用场，如下所示：

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {
    @Autowired
    UserDetailsService userDetailsService;

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        OpenSaml4AuthenticationProvider authenticationProvider = new OpenSaml4AuthenticationProvider();
        authenticationProvider.setResponseAuthenticationConverter(responseToken -> {
            Saml2Authentication authentication = OpenSaml4AuthenticationProvider
                    .createDefaultResponseAuthenticationConverter() 1
                    .convert(responseToken);
            Assertion assertion = responseToken.getResponse().getAssertions().get(0);
            String username = assertion.getSubject().getNameID().getValue();
            UserDetails userDetails = this.userDetailsService.loadUserByUsername(username); 2
            return MySaml2Authentication(userDetails, authentication); 3
        });

        http
            .authorizeHttpRequests(authz -> authz
                .anyRequest().authenticated()
            )
            .saml2Login(saml2 -> saml2
                .authenticationManager(new ProviderManager(authenticationProvider))
            );
        return http.build();
    }
}

@Configuration
@EnableWebSecurity
open class SecurityConfig {
    @Autowired
    var userDetailsService: UserDetailsService? = null

    @Bean
    open fun filterChain(http: HttpSecurity): SecurityFilterChain {
        val authenticationProvider = OpenSaml4AuthenticationProvider()
        authenticationProvider.setResponseAuthenticationConverter { responseToken: OpenSaml4AuthenticationProvider.ResponseToken ->
            val authentication = OpenSaml4AuthenticationProvider
                .createDefaultResponseAuthenticationConverter() 1
                .convert(responseToken)
            val assertion: Assertion = responseToken.response.assertions[0]
            val username: String = assertion.subject.nameID.value
            val userDetails = userDetailsService!!.loadUserByUsername(username) 2
            MySaml2Authentication(userDetails, authentication) 3
        }
        http {
            authorizeRequests {
                authorize(anyRequest, authenticated)
            }
            saml2Login {
                authenticationManager = ProviderManager(authenticationProvider)
            }
        }
        return http.build()
    }
}

1	首先，调用默认转换器，它从响应中提取属性和授权
2	其次，使用相关信息调用 `UserDetailsService`
3	第三，返回包含用户详细信息的自定义身份验证

从 AttributeStatement`s as well as the single `ROLE_USER 主体中提取属性的 OpenSaml4AuthenticationProvider’s default authentication converter. It returns a `Saml2AuthenticatedPrincipal 不必调用。

Performing Additional Response Validation

OpenSaml4AuthenticationProvider 在解密 Response 后立即验证 Issuer 和 Destination 值。可以通过将默认验证器与您自己的响应验证器串联起来来自定义验证，或者您可以将其完全替换为您自己的。

例如，您可以使用 Response 对象中可用的任何附加信息抛出自定义异常，如下所示：

OpenSaml4AuthenticationProvider provider = new OpenSaml4AuthenticationProvider();
provider.setResponseValidator((responseToken) -> {
	Saml2ResponseValidatorResult result = OpenSamlAuthenticationProvider
		.createDefaultResponseValidator()
		.convert(responseToken)
		.concat(myCustomValidator.convert(responseToken));
	if (!result.getErrors().isEmpty()) {
		String inResponseTo = responseToken.getInResponseTo();
		throw new CustomSaml2AuthenticationException(result, inResponseTo);
	}
	return result;
});

Performing Additional Assertion Validation

OpenSaml4AuthenticationProvider 对 SAML 2.0 断言执行最小验证。在验证签名后，它将：

验证 `<AudienceRestriction>`和 `<DelegationRestriction>`条件
验证 <SubjectConfirmation>，期望为 IP 地址信息

为了执行附加验证，您可以配置自己的断言验证器，该断言验证器委托给“OpenSaml4AuthenticationProvider”的默认验证器，然后执行自己的验证器。

例如，您可以使用 OpenSAML 的 OneTimeUseConditionValidator 来验证 <OneTimeUse> 条件，如下所示：

Java
Kotlin

OpenSaml4AuthenticationProvider provider = new OpenSaml4AuthenticationProvider();
OneTimeUseConditionValidator validator = ...;
provider.setAssertionValidator(assertionToken -> {
    Saml2ResponseValidatorResult result = OpenSaml4AuthenticationProvider
            .createDefaultAssertionValidator()
            .convert(assertionToken);
    Assertion assertion = assertionToken.getAssertion();
    OneTimeUse oneTimeUse = assertion.getConditions().getOneTimeUse();
    ValidationContext context = new ValidationContext();
    try {
        if (validator.validate(oneTimeUse, assertion, context) = ValidationResult.VALID) {
            return result;
        }
    } catch (Exception e) {
        return result.concat(new Saml2Error(INVALID_ASSERTION, e.getMessage()));
    }
    return result.concat(new Saml2Error(INVALID_ASSERTION, context.getValidationFailureMessage()));
});

var provider = OpenSaml4AuthenticationProvider()
var validator: OneTimeUseConditionValidator = ...
provider.setAssertionValidator { assertionToken ->
    val result = OpenSaml4AuthenticationProvider
        .createDefaultAssertionValidator()
        .convert(assertionToken)
    val assertion: Assertion = assertionToken.assertion
    val oneTimeUse: OneTimeUse = assertion.conditions.oneTimeUse
    val context = ValidationContext()
    try {
        if (validator.validate(oneTimeUse, assertion, context) = ValidationResult.VALID) {
            return@setAssertionValidator result
        }
    } catch (e: Exception) {
        return@setAssertionValidator result.concat(Saml2Error(INVALID_ASSERTION, e.message))
    }
    result.concat(Saml2Error(INVALID_ASSERTION, context.validationFailureMessage))
}

尽管建议调用 OpenSaml4AuthenticationProvider’s default assertion validator. A circumstance where you would skip it would be if you don’t need it to check the `<AudienceRestriction> 或 <SubjectConfirmation>，但由于您对其进行自行处理，因此不必调用。

Customizing Decryption

Spring Security 使用在 RelyingPartyRegistration 中注册的解密 Saml2X509Credential instances 自动解密 <saml2:EncryptedAssertion>、<saml2:EncryptedAttribute> 和 <saml2:EncryptedID> 元素。

OpenSaml4AuthenticationProvider`公开 two decryption strategies。响应解密器用于解密 `<saml2:Response>`的加密元素，如 `<saml2:EncryptedAssertion>。断言解密器用于解密 <saml2:Assertion>`的加密元素，如 `<saml2:EncryptedAttribute>`和 `<saml2:EncryptedID>。

可替换 OpenSaml4AuthenticationProvider’s default decryption strategy with your own. For example, if you have a separate service that decrypts the assertions in a `<saml2:Response>，可像如下所示使用它：

Java
Kotlin

MyDecryptionService decryptionService = ...;
OpenSaml4AuthenticationProvider provider = new OpenSaml4AuthenticationProvider();
provider.setResponseElementsDecrypter((responseToken) -> decryptionService.decrypt(responseToken.getResponse()));

val decryptionService: MyDecryptionService = ...
val provider = OpenSaml4AuthenticationProvider()
provider.setResponseElementsDecrypter { responseToken -> decryptionService.decrypt(responseToken.response) }

如果你还在 RFC 1901 中解密各个元素，也可以自定义断言解密器：

Java
Kotlin

provider.setAssertionElementsDecrypter((assertionToken) -> decryptionService.decrypt(assertionToken.getAssertion()));

provider.setAssertionElementsDecrypter { assertionToken -> decryptionService.decrypt(assertionToken.assertion) }

之所以有两个单独的解密器，是因为断言可以从响应中分别进行签名。在验证签名之前尝试解密已签名断言的元素可能会使签名无效。如果断言方只签署响应，则仅使用响应解密器解密所有元素是安全的。

Using a Custom Authentication Manager

当然，authenticationManager DSL 方法也可用于执行完全自定义的 SAML 2.0 身份验证。此身份验证管理器应期望一个包含 SAML 2.0 响应 XML 数据的 Saml2AuthenticationToken 对象。

Java
Kotlin

@Configuration
@EnableWebSecurity
public class SecurityConfig {

    @Bean
	public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        AuthenticationManager authenticationManager = new MySaml2AuthenticationManager(...);
        http
            .authorizeHttpRequests(authorize -> authorize
                .anyRequest().authenticated()
            )
            .saml2Login(saml2 -> saml2
                .authenticationManager(authenticationManager)
            )
        ;
        return http.build();
    }
}

@Configuration
@EnableWebSecurity
open class SecurityConfig {
    @Bean
    open fun filterChain(http: HttpSecurity): SecurityFilterChain {
        val customAuthenticationManager: AuthenticationManager = MySaml2AuthenticationManager(...)
        http {
            authorizeRequests {
                authorize(anyRequest, authenticated)
            }
            saml2Login {
                authenticationManager = customAuthenticationManager
            }
        }
        return http.build()
    }
}

Using `Saml2AuthenticatedPrincipal`

依靠方为给定的断言方正确配置后，即可接受断言。一旦依靠方验证断言，结果就是具有 RFC 1901 的 Saml2Authentication。

这意味着你可以像如下所示在控制器中访问主体：

Java
Kotlin

@Controller
public class MainController {
	@GetMapping("/")
	public String index(@AuthenticationPrincipal Saml2AuthenticatedPrincipal principal, Model model) {
		String email = principal.getFirstAttribute("email");
		model.setAttribute("email", email);
		return "index";
	}
}

@Controller
class MainController {
    @GetMapping("/")
    fun index(@AuthenticationPrincipal principal: Saml2AuthenticatedPrincipal, model: Model): String {
        val email = principal.getFirstAttribute<String>("email")
        model.setAttribute("email", email)
        return "index"
    }
}

由于 SAML 2.0 规范允许每个属性拥有多个值，您既可以调用 getAttribute 来获取属性列表，也可以调用 getFirstAttribute 来获取列表中的第一个值。当您知道只有一个值时，getFirstAttribute 非常方便。

Authenticating `<saml2:Response>`s

Changing the SAML Response Processing Endpoint

Changing RelyingPartyRegistration lookup

Setting a Clock Skew

Coordinating with a UserDetailsService

Performing Additional Response Validation

Performing Additional Assertion Validation

Customizing Decryption

Using a Custom Authentication Manager

Using Saml2AuthenticatedPrincipal

Changing `RelyingPartyRegistration` lookup

Coordinating with a `UserDetailsService`

Using `Saml2AuthenticatedPrincipal`