Use OpenSAML API for metadata

Issue gh-11658

config/src/main/java/org/springframework/security/config/annotation/web/configurers/saml2/Saml2MetadataConfigurer.java

@@ -22,7 +22,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.security.config.annotation.web.HttpSecurityBuilder;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configurers.AbstractHttpConfigurer;
-import org.springframework.security.saml2.provider.service.metadata.OpenSamlMetadataResolver;
+import org.springframework.security.saml2.provider.service.metadata.OpenSaml4MetadataResolver;
 import org.springframework.security.saml2.provider.service.metadata.Saml2MetadataResponseResolver;
 import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
 import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistrationRepository;
@@ -104,7 +104,7 @@ public class Saml2MetadataConfigurer<H extends HttpSecurityBuilder<H>>
 		Assert.hasText(metadataUrl, "metadataUrl cannot be empty");
 		this.metadataResponseResolver = (registrations) -> {
 			RequestMatcherMetadataResponseResolver metadata = new RequestMatcherMetadataResponseResolver(registrations,
-					new OpenSamlMetadataResolver());
+					new OpenSaml4MetadataResolver());
 			metadata.setRequestMatcher(new AntPathRequestMatcher(metadataUrl));
 			return metadata;
 		};
@@ -143,7 +143,7 @@ public class Saml2MetadataConfigurer<H extends HttpSecurityBuilder<H>>
 			return metadataResponseResolver;
 		}
 		RelyingPartyRegistrationRepository registrations = getRelyingPartyRegistrationRepository(http);
-		return new RequestMatcherMetadataResponseResolver(registrations, new OpenSamlMetadataResolver());
+		return new RequestMatcherMetadataResponseResolver(registrations, new OpenSaml4MetadataResolver());
 	}
 
 	private RelyingPartyRegistrationRepository getRelyingPartyRegistrationRepository(H http) {

config/src/test/java/org/springframework/security/config/annotation/web/configurers/saml2/Saml2MetadataConfigurerTests.java

@@ -30,7 +30,7 @@ import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
 import org.springframework.security.config.test.SpringTestContext;
 import org.springframework.security.config.test.SpringTestContextExtension;
-import org.springframework.security.saml2.provider.service.metadata.OpenSamlMetadataResolver;
+import org.springframework.security.saml2.provider.service.metadata.OpenSaml4MetadataResolver;
 import org.springframework.security.saml2.provider.service.metadata.RequestMatcherMetadataResponseResolver;
 import org.springframework.security.saml2.provider.service.metadata.Saml2MetadataResponse;
 import org.springframework.security.saml2.provider.service.metadata.Saml2MetadataResponseResolver;
@@ -159,7 +159,7 @@ public class Saml2MetadataConfigurerTests {
 		// should ignore
 		@Bean
 		Saml2MetadataResponseResolver metadataResponseResolver(RelyingPartyRegistrationRepository registrations) {
-			return new RequestMatcherMetadataResponseResolver(registrations, new OpenSamlMetadataResolver());
+			return new RequestMatcherMetadataResponseResolver(registrations, new OpenSaml4MetadataResolver());
 		}
 
 	}

saml2/saml2-service-provider/spring-security-saml2-service-provider.gradle

@@ -19,6 +19,12 @@ sourceSets.configureEach { set ->
 		filter { line -> line.replaceAll(".saml2.internal", ".saml2.provider.service.authentication") }
 		with from
 	}
+
+	copy {
+		into "$projectDir/src/$set.name/java/org/springframework/security/saml2/provider/service/metadata"
+		filter { line -> line.replaceAll(".saml2.internal", ".saml2.provider.service.metadata") }
+		with from
+	}
 }
 
 dependencies {

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/BaseOpenSamlMetadataResolver.java

@@ -0,0 +1,250 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.metadata;
+
+import java.security.cert.CertificateEncodingException;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Consumer;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.opensaml.saml.common.xml.SAMLConstants;
+import org.opensaml.saml.saml2.metadata.AssertionConsumerService;
+import org.opensaml.saml.saml2.metadata.EntitiesDescriptor;
+import org.opensaml.saml.saml2.metadata.EntityDescriptor;
+import org.opensaml.saml.saml2.metadata.KeyDescriptor;
+import org.opensaml.saml.saml2.metadata.NameIDFormat;
+import org.opensaml.saml.saml2.metadata.SPSSODescriptor;
+import org.opensaml.saml.saml2.metadata.SingleLogoutService;
+import org.opensaml.security.credential.UsageType;
+import org.opensaml.xmlsec.signature.KeyInfo;
+import org.opensaml.xmlsec.signature.X509Certificate;
+import org.opensaml.xmlsec.signature.X509Data;
+
+import org.springframework.security.saml2.Saml2Exception;
+import org.springframework.security.saml2.core.OpenSamlInitializationService;
+import org.springframework.security.saml2.core.Saml2X509Credential;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
+import org.springframework.security.saml2.provider.service.registration.Saml2MessageBinding;
+import org.springframework.util.Assert;
+
+/**
+ * Resolves the SAML 2.0 Relying Party Metadata for a given
+ * {@link RelyingPartyRegistration} using the OpenSAML API.
+ *
+ * @author Jakub Kubrynski
+ * @author Josh Cummings
+ * @since 5.4
+ */
+final class BaseOpenSamlMetadataResolver implements Saml2MetadataResolver {
+
+	static {
+		OpenSamlInitializationService.initialize();
+	}
+
+	private final Log logger = LogFactory.getLog(this.getClass());
+
+	private OpenSamlOperations saml;
+
+	private Consumer<EntityDescriptorParameters> entityDescriptorCustomizer = (parameters) -> {
+	};
+
+	private boolean usePrettyPrint = true;
+
+	private boolean signMetadata = false;
+
+	BaseOpenSamlMetadataResolver(OpenSamlOperations saml) {
+		this.saml = saml;
+	}
+
+	@Override
+	public String resolve(RelyingPartyRegistration relyingPartyRegistration) {
+		EntityDescriptor entityDescriptor = entityDescriptor(relyingPartyRegistration);
+		return serialize(entityDescriptor);
+	}
+
+	@Override
+	public String resolve(Iterable<RelyingPartyRegistration> relyingPartyRegistrations) {
+		Collection<EntityDescriptor> entityDescriptors = new ArrayList<>();
+		for (RelyingPartyRegistration registration : relyingPartyRegistrations) {
+			EntityDescriptor entityDescriptor = entityDescriptor(registration);
+			entityDescriptors.add(entityDescriptor);
+		}
+		if (entityDescriptors.size() == 1) {
+			return serialize(entityDescriptors.iterator().next());
+		}
+		EntitiesDescriptor entities = this.saml.build(EntitiesDescriptor.DEFAULT_ELEMENT_NAME);
+		entities.getEntityDescriptors().addAll(entityDescriptors);
+		return serialize(entities);
+	}
+
+	private EntityDescriptor entityDescriptor(RelyingPartyRegistration registration) {
+		EntityDescriptor entityDescriptor = this.saml.build(EntityDescriptor.DEFAULT_ELEMENT_NAME);
+		entityDescriptor.setEntityID(registration.getEntityId());
+		SPSSODescriptor spSsoDescriptor = buildSpSsoDescriptor(registration);
+		entityDescriptor.getRoleDescriptors(SPSSODescriptor.DEFAULT_ELEMENT_NAME).add(spSsoDescriptor);
+		this.entityDescriptorCustomizer.accept(new EntityDescriptorParameters(entityDescriptor, registration));
+		if (this.signMetadata) {
+			return this.saml.withSigningKeys(registration.getSigningX509Credentials())
+				.algorithms(registration.getAssertingPartyMetadata().getSigningAlgorithms())
+				.sign(entityDescriptor);
+		}
+		else {
+			this.logger.trace("Did not sign metadata since `signMetadata` is `false`");
+		}
+		return entityDescriptor;
+	}
+
+	/**
+	 * Set a {@link Consumer} for modifying the OpenSAML {@link EntityDescriptor}
+	 * @param entityDescriptorCustomizer a consumer that accepts an
+	 * {@link EntityDescriptorParameters}
+	 * @since 5.7
+	 */
+	void setEntityDescriptorCustomizer(Consumer<EntityDescriptorParameters> entityDescriptorCustomizer) {
+		Assert.notNull(entityDescriptorCustomizer, "entityDescriptorCustomizer cannot be null");
+		this.entityDescriptorCustomizer = entityDescriptorCustomizer;
+	}
+
+	/**
+	 * Configure whether to pretty-print the metadata XML. This can be helpful when
+	 * signing the metadata payload.
+	 *
+	 * @since 6.2
+	 **/
+	void setUsePrettyPrint(boolean usePrettyPrint) {
+		this.usePrettyPrint = usePrettyPrint;
+	}
+
+	private SPSSODescriptor buildSpSsoDescriptor(RelyingPartyRegistration registration) {
+		SPSSODescriptor spSsoDescriptor = this.saml.build(SPSSODescriptor.DEFAULT_ELEMENT_NAME);
+		spSsoDescriptor.addSupportedProtocol(SAMLConstants.SAML20P_NS);
+		spSsoDescriptor.getKeyDescriptors()
+			.addAll(buildKeys(registration.getSigningX509Credentials(), UsageType.SIGNING));
+		spSsoDescriptor.getKeyDescriptors()
+			.addAll(buildKeys(registration.getDecryptionX509Credentials(), UsageType.ENCRYPTION));
+		spSsoDescriptor.getAssertionConsumerServices().add(buildAssertionConsumerService(registration));
+		if (registration.getSingleLogoutServiceLocation() != null) {
+			for (Saml2MessageBinding binding : registration.getSingleLogoutServiceBindings()) {
+				spSsoDescriptor.getSingleLogoutServices().add(buildSingleLogoutService(registration, binding));
+			}
+		}
+		if (registration.getNameIdFormat() != null) {
+			spSsoDescriptor.getNameIDFormats().add(buildNameIDFormat(registration));
+		}
+		return spSsoDescriptor;
+	}
+
+	private List<KeyDescriptor> buildKeys(Collection<Saml2X509Credential> credentials, UsageType usageType) {
+		List<KeyDescriptor> list = new ArrayList<>();
+		for (Saml2X509Credential credential : credentials) {
+			KeyDescriptor keyDescriptor = buildKeyDescriptor(usageType, credential.getCertificate());
+			list.add(keyDescriptor);
+		}
+		return list;
+	}
+
+	private KeyDescriptor buildKeyDescriptor(UsageType usageType, java.security.cert.X509Certificate certificate) {
+		KeyDescriptor keyDescriptor = this.saml.build(KeyDescriptor.DEFAULT_ELEMENT_NAME);
+		KeyInfo keyInfo = this.saml.build(KeyInfo.DEFAULT_ELEMENT_NAME);
+		X509Certificate x509Certificate = this.saml.build(X509Certificate.DEFAULT_ELEMENT_NAME);
+		X509Data x509Data = this.saml.build(X509Data.DEFAULT_ELEMENT_NAME);
+		try {
+			x509Certificate.setValue(new String(Base64.getEncoder().encode(certificate.getEncoded())));
+		}
+		catch (CertificateEncodingException ex) {
+			throw new Saml2Exception("Cannot encode certificate " + certificate.toString());
+		}
+		x509Data.getX509Certificates().add(x509Certificate);
+		keyInfo.getX509Datas().add(x509Data);
+		keyDescriptor.setUse(usageType);
+		keyDescriptor.setKeyInfo(keyInfo);
+		return keyDescriptor;
+	}
+
+	private AssertionConsumerService buildAssertionConsumerService(RelyingPartyRegistration registration) {
+		AssertionConsumerService assertionConsumerService = this.saml
+			.build(AssertionConsumerService.DEFAULT_ELEMENT_NAME);
+		assertionConsumerService.setLocation(registration.getAssertionConsumerServiceLocation());
+		assertionConsumerService.setBinding(registration.getAssertionConsumerServiceBinding().getUrn());
+		assertionConsumerService.setIndex(1);
+		return assertionConsumerService;
+	}
+
+	private SingleLogoutService buildSingleLogoutService(RelyingPartyRegistration registration,
+			Saml2MessageBinding binding) {
+		SingleLogoutService singleLogoutService = this.saml.build(SingleLogoutService.DEFAULT_ELEMENT_NAME);
+		singleLogoutService.setLocation(registration.getSingleLogoutServiceLocation());
+		singleLogoutService.setResponseLocation(registration.getSingleLogoutServiceResponseLocation());
+		singleLogoutService.setBinding(binding.getUrn());
+		return singleLogoutService;
+	}
+
+	private NameIDFormat buildNameIDFormat(RelyingPartyRegistration registration) {
+		NameIDFormat nameIdFormat = this.saml.build(NameIDFormat.DEFAULT_ELEMENT_NAME);
+		nameIdFormat.setURI(registration.getNameIdFormat());
+		return nameIdFormat;
+	}
+
+	private String serialize(EntityDescriptor entityDescriptor) {
+		return this.saml.serialize(entityDescriptor).prettyPrint(this.usePrettyPrint).serialize();
+	}
+
+	private String serialize(EntitiesDescriptor entities) {
+		return this.saml.serialize(entities).prettyPrint(this.usePrettyPrint).serialize();
+	}
+
+	/**
+	 * Configure whether to sign the metadata, defaults to {@code false}.
+	 *
+	 * @since 6.4
+	 */
+	void setSignMetadata(boolean signMetadata) {
+		this.signMetadata = signMetadata;
+	}
+
+	/**
+	 * A tuple containing an OpenSAML {@link EntityDescriptor} and its associated
+	 * {@link RelyingPartyRegistration}
+	 *
+	 * @since 5.7
+	 */
+	static final class EntityDescriptorParameters {
+
+		private final EntityDescriptor entityDescriptor;
+
+		private final RelyingPartyRegistration registration;
+
+		EntityDescriptorParameters(EntityDescriptor entityDescriptor, RelyingPartyRegistration registration) {
+			this.entityDescriptor = entityDescriptor;
+			this.registration = registration;
+		}
+
+		EntityDescriptor getEntityDescriptor() {
+			return this.entityDescriptor;
+		}
+
+		RelyingPartyRegistration getRelyingPartyRegistration() {
+			return this.registration;
+		}
+
+	}
+
+}

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/OpenSaml4MetadataResolver.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.metadata;
+
+import java.util.function.Consumer;
+
+import org.opensaml.saml.saml2.metadata.EntityDescriptor;
+
+import org.springframework.security.saml2.core.OpenSamlInitializationService;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
+
+/**
+ * Resolves the SAML 2.0 Relying Party Metadata for a given
+ * {@link RelyingPartyRegistration} using the OpenSAML API.
+ *
+ * @author Jakub Kubrynski
+ * @author Josh Cummings
+ * @since 5.4
+ */
+public final class OpenSaml4MetadataResolver implements Saml2MetadataResolver {
+
+	static {
+		OpenSamlInitializationService.initialize();
+	}
+
+	private final BaseOpenSamlMetadataResolver delegate;
+
+	public OpenSaml4MetadataResolver() {
+		this.delegate = new BaseOpenSamlMetadataResolver(new OpenSaml4Template());
+	}
+
+	@Override
+	public String resolve(RelyingPartyRegistration relyingPartyRegistration) {
+		return this.delegate.resolve(relyingPartyRegistration);
+	}
+
+	public String resolve(Iterable<RelyingPartyRegistration> relyingPartyRegistrations) {
+		return this.delegate.resolve(relyingPartyRegistrations);
+	}
+
+	/**
+	 * Set a {@link Consumer} for modifying the OpenSAML {@link EntityDescriptor}
+	 * @param entityDescriptorCustomizer a consumer that accepts an
+	 * {@link EntityDescriptorParameters}
+	 * @since 5.7
+	 */
+	public void setEntityDescriptorCustomizer(Consumer<EntityDescriptorParameters> entityDescriptorCustomizer) {
+		this.delegate.setEntityDescriptorCustomizer(
+				(parameters) -> entityDescriptorCustomizer.accept(new EntityDescriptorParameters(parameters)));
+	}
+
+	/**
+	 * Configure whether to pretty-print the metadata XML. This can be helpful when
+	 * signing the metadata payload.
+	 *
+	 * @since 6.2
+	 **/
+	public void setUsePrettyPrint(boolean usePrettyPrint) {
+		this.delegate.setUsePrettyPrint(usePrettyPrint);
+	}
+
+	/**
+	 * Configure whether to sign the metadata, defaults to {@code false}.
+	 *
+	 * @since 6.4
+	 */
+	public void setSignMetadata(boolean signMetadata) {
+		this.delegate.setSignMetadata(signMetadata);
+	}
+
+	/**
+	 * A tuple containing an OpenSAML {@link EntityDescriptor} and its associated
+	 * {@link RelyingPartyRegistration}
+	 *
+	 * @since 5.7
+	 */
+	public static final class EntityDescriptorParameters {
+
+		private final EntityDescriptor entityDescriptor;
+
+		private final RelyingPartyRegistration registration;
+
+		public EntityDescriptorParameters(EntityDescriptor entityDescriptor, RelyingPartyRegistration registration) {
+			this.entityDescriptor = entityDescriptor;
+			this.registration = registration;
+		}
+
+		EntityDescriptorParameters(BaseOpenSamlMetadataResolver.EntityDescriptorParameters parameters) {
+			this.entityDescriptor = parameters.getEntityDescriptor();
+			this.registration = parameters.getRelyingPartyRegistration();
+		}
+
+		public EntityDescriptor getEntityDescriptor() {
+			return this.entityDescriptor;
+		}
+
+		public RelyingPartyRegistration getRelyingPartyRegistration() {
+			return this.registration;
+		}
+
+	}
+
+}

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/OpenSaml4Template.java

@@ -0,0 +1,617 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.metadata;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.security.PrivateKey;
+import java.security.cert.X509Certificate;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import javax.xml.namespace.QName;
+
+import net.shibboleth.utilities.java.support.resolver.CriteriaSet;
+import net.shibboleth.utilities.java.support.xml.SerializeSupport;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.opensaml.core.criterion.EntityIdCriterion;
+import org.opensaml.core.xml.XMLObject;
+import org.opensaml.core.xml.XMLObjectBuilder;
+import org.opensaml.core.xml.config.XMLObjectProviderRegistrySupport;
+import org.opensaml.core.xml.io.Marshaller;
+import org.opensaml.core.xml.io.MarshallingException;
+import org.opensaml.core.xml.io.Unmarshaller;
+import org.opensaml.core.xml.io.UnmarshallerFactory;
+import org.opensaml.core.xml.util.XMLObjectSupport;
+import org.opensaml.saml.common.xml.SAMLConstants;
+import org.opensaml.saml.criterion.ProtocolCriterion;
+import org.opensaml.saml.ext.saml2delrestrict.Delegate;
+import org.opensaml.saml.ext.saml2delrestrict.DelegationRestrictionType;
+import org.opensaml.saml.metadata.criteria.role.impl.EvaluableProtocolRoleDescriptorCriterion;
+import org.opensaml.saml.saml2.core.Assertion;
+import org.opensaml.saml.saml2.core.Attribute;
+import org.opensaml.saml.saml2.core.AttributeStatement;
+import org.opensaml.saml.saml2.core.Condition;
+import org.opensaml.saml.saml2.core.EncryptedAssertion;
+import org.opensaml.saml.saml2.core.EncryptedAttribute;
+import org.opensaml.saml.saml2.core.Issuer;
+import org.opensaml.saml.saml2.core.LogoutRequest;
+import org.opensaml.saml.saml2.core.NameID;
+import org.opensaml.saml.saml2.core.RequestAbstractType;
+import org.opensaml.saml.saml2.core.Response;
+import org.opensaml.saml.saml2.core.StatusResponseType;
+import org.opensaml.saml.saml2.core.Subject;
+import org.opensaml.saml.saml2.core.SubjectConfirmation;
+import org.opensaml.saml.saml2.encryption.Decrypter;
+import org.opensaml.saml.saml2.encryption.EncryptedElementTypeEncryptedKeyResolver;
+import org.opensaml.saml.security.impl.SAMLMetadataSignatureSigningParametersResolver;
+import org.opensaml.saml.security.impl.SAMLSignatureProfileValidator;
+import org.opensaml.security.SecurityException;
+import org.opensaml.security.credential.BasicCredential;
+import org.opensaml.security.credential.Credential;
+import org.opensaml.security.credential.CredentialResolver;
+import org.opensaml.security.credential.CredentialSupport;
+import org.opensaml.security.credential.UsageType;
+import org.opensaml.security.credential.criteria.impl.EvaluableEntityIDCredentialCriterion;
+import org.opensaml.security.credential.criteria.impl.EvaluableUsageCredentialCriterion;
+import org.opensaml.security.credential.impl.CollectionCredentialResolver;
+import org.opensaml.security.criteria.UsageCriterion;
+import org.opensaml.security.x509.BasicX509Credential;
+import org.opensaml.xmlsec.SignatureSigningParameters;
+import org.opensaml.xmlsec.SignatureSigningParametersResolver;
+import org.opensaml.xmlsec.config.impl.DefaultSecurityConfigurationBootstrap;
+import org.opensaml.xmlsec.criterion.SignatureSigningConfigurationCriterion;
+import org.opensaml.xmlsec.crypto.XMLSigningUtil;
+import org.opensaml.xmlsec.encryption.support.ChainingEncryptedKeyResolver;
+import org.opensaml.xmlsec.encryption.support.DecryptionException;
+import org.opensaml.xmlsec.encryption.support.EncryptedKeyResolver;
+import org.opensaml.xmlsec.encryption.support.InlineEncryptedKeyResolver;
+import org.opensaml.xmlsec.encryption.support.SimpleRetrievalMethodEncryptedKeyResolver;
+import org.opensaml.xmlsec.impl.BasicSignatureSigningConfiguration;
+import org.opensaml.xmlsec.keyinfo.KeyInfoCredentialResolver;
+import org.opensaml.xmlsec.keyinfo.KeyInfoGeneratorManager;
+import org.opensaml.xmlsec.keyinfo.NamedKeyInfoGeneratorManager;
+import org.opensaml.xmlsec.keyinfo.impl.CollectionKeyInfoCredentialResolver;
+import org.opensaml.xmlsec.keyinfo.impl.X509KeyInfoGeneratorFactory;
+import org.opensaml.xmlsec.signature.SignableXMLObject;
+import org.opensaml.xmlsec.signature.Signature;
+import org.opensaml.xmlsec.signature.support.SignatureConstants;
+import org.opensaml.xmlsec.signature.support.SignatureSupport;
+import org.opensaml.xmlsec.signature.support.SignatureTrustEngine;
+import org.opensaml.xmlsec.signature.support.impl.ExplicitKeySignatureTrustEngine;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+import org.springframework.security.saml2.Saml2Exception;
+import org.springframework.security.saml2.core.Saml2Error;
+import org.springframework.security.saml2.core.Saml2ErrorCodes;
+import org.springframework.security.saml2.core.Saml2ParameterNames;
+import org.springframework.security.saml2.core.Saml2X509Credential;
+import org.springframework.util.Assert;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.web.util.UriUtils;
+
+/**
+ * For internal use only. Subject to breaking changes at any time.
+ */
+final class OpenSaml4Template implements OpenSamlOperations {
+
+	private static final Log logger = LogFactory.getLog(OpenSaml4Template.class);
+
+	@Override
+	public <T extends XMLObject> T build(QName elementName) {
+		XMLObjectBuilder<?> builder = XMLObjectProviderRegistrySupport.getBuilderFactory().getBuilder(elementName);
+		if (builder == null) {
+			throw new Saml2Exception("Unable to resolve Builder for " + elementName);
+		}
+		return (T) builder.buildObject(elementName);
+	}
+
+	@Override
+	public <T extends XMLObject> T deserialize(String serialized) {
+		return deserialize(new ByteArrayInputStream(serialized.getBytes(StandardCharsets.UTF_8)));
+	}
+
+	@Override
+	public <T extends XMLObject> T deserialize(InputStream serialized) {
+		try {
+			Document document = XMLObjectProviderRegistrySupport.getParserPool().parse(serialized);
+			Element element = document.getDocumentElement();
+			UnmarshallerFactory factory = XMLObjectProviderRegistrySupport.getUnmarshallerFactory();
+			Unmarshaller unmarshaller = factory.getUnmarshaller(element);
+			if (unmarshaller == null) {
+				throw new Saml2Exception("Unsupported element of type " + element.getTagName());
+			}
+			return (T) unmarshaller.unmarshall(element);
+		}
+		catch (Saml2Exception ex) {
+			throw ex;
+		}
+		catch (Exception ex) {
+			throw new Saml2Exception("Failed to deserialize payload", ex);
+		}
+	}
+
+	@Override
+	public OpenSaml4SerializationConfigurer serialize(XMLObject object) {
+		Marshaller marshaller = XMLObjectProviderRegistrySupport.getMarshallerFactory().getMarshaller(object);
+		try {
+			return serialize(marshaller.marshall(object));
+		}
+		catch (MarshallingException ex) {
+			throw new Saml2Exception(ex);
+		}
+	}
+
+	@Override
+	public OpenSaml4SerializationConfigurer serialize(Element element) {
+		return new OpenSaml4SerializationConfigurer(element);
+	}
+
+	@Override
+	public OpenSaml4SignatureConfigurer withSigningKeys(Collection<Saml2X509Credential> credentials) {
+		return new OpenSaml4SignatureConfigurer(credentials);
+	}
+
+	@Override
+	public OpenSaml4VerificationConfigurer withVerificationKeys(Collection<Saml2X509Credential> credentials) {
+		return new OpenSaml4VerificationConfigurer(credentials);
+	}
+
+	@Override
+	public OpenSaml4DecryptionConfigurer withDecryptionKeys(Collection<Saml2X509Credential> credentials) {
+		return new OpenSaml4DecryptionConfigurer(credentials);
+	}
+
+	OpenSaml4Template() {
+
+	}
+
+	static final class OpenSaml4SerializationConfigurer
+			implements SerializationConfigurer<OpenSaml4SerializationConfigurer> {
+
+		private final Element element;
+
+		boolean pretty;
+
+		OpenSaml4SerializationConfigurer(Element element) {
+			this.element = element;
+		}
+
+		@Override
+		public OpenSaml4SerializationConfigurer prettyPrint(boolean pretty) {
+			this.pretty = pretty;
+			return this;
+		}
+
+		@Override
+		public String serialize() {
+			if (this.pretty) {
+				return SerializeSupport.prettyPrintXML(this.element);
+			}
+			return SerializeSupport.nodeToString(this.element);
+		}
+
+	}
+
+	static final class OpenSaml4SignatureConfigurer implements SignatureConfigurer<OpenSaml4SignatureConfigurer> {
+
+		private final Collection<Saml2X509Credential> credentials;
+
+		private final Map<String, String> components = new LinkedHashMap<>();
+
+		private List<String> algs = List.of(SignatureConstants.ALGO_ID_SIGNATURE_RSA_SHA256);
+
+		OpenSaml4SignatureConfigurer(Collection<Saml2X509Credential> credentials) {
+			this.credentials = credentials;
+		}
+
+		@Override
+		public OpenSaml4SignatureConfigurer algorithms(List<String> algs) {
+			this.algs = algs;
+			return this;
+		}
+
+		@Override
+		public <O extends SignableXMLObject> O sign(O object) {
+			SignatureSigningParameters parameters = resolveSigningParameters();
+			try {
+				SignatureSupport.signObject(object, parameters);
+			}
+			catch (Exception ex) {
+				throw new Saml2Exception(ex);
+			}
+			return object;
+		}
+
+		@Override
+		public Map<String, String> sign(Map<String, String> params) {
+			SignatureSigningParameters parameters = resolveSigningParameters();
+			this.components.putAll(params);
+			Credential credential = parameters.getSigningCredential();
+			String algorithmUri = parameters.getSignatureAlgorithm();
+			this.components.put(Saml2ParameterNames.SIG_ALG, algorithmUri);
+			UriComponentsBuilder builder = UriComponentsBuilder.newInstance();
+			for (Map.Entry<String, String> component : this.components.entrySet()) {
+				builder.queryParam(component.getKey(),
+						UriUtils.encode(component.getValue(), StandardCharsets.ISO_8859_1));
+			}
+			String queryString = builder.build(true).toString().substring(1);
+			try {
+				byte[] rawSignature = XMLSigningUtil.signWithURI(credential, algorithmUri,
+						queryString.getBytes(StandardCharsets.UTF_8));
+				String b64Signature = Saml2Utils.samlEncode(rawSignature);
+				this.components.put(Saml2ParameterNames.SIGNATURE, b64Signature);
+			}
+			catch (SecurityException ex) {
+				throw new Saml2Exception(ex);
+			}
+			return this.components;
+		}
+
+		private SignatureSigningParameters resolveSigningParameters() {
+			List<Credential> credentials = resolveSigningCredentials();
+			List<String> digests = Collections.singletonList(SignatureConstants.ALGO_ID_DIGEST_SHA256);
+			String canonicalization = SignatureConstants.ALGO_ID_C14N_EXCL_OMIT_COMMENTS;
+			SignatureSigningParametersResolver resolver = new SAMLMetadataSignatureSigningParametersResolver();
+			BasicSignatureSigningConfiguration signingConfiguration = new BasicSignatureSigningConfiguration();
+			signingConfiguration.setSigningCredentials(credentials);
+			signingConfiguration.setSignatureAlgorithms(this.algs);
+			signingConfiguration.setSignatureReferenceDigestMethods(digests);
+			signingConfiguration.setSignatureCanonicalizationAlgorithm(canonicalization);
+			signingConfiguration.setKeyInfoGeneratorManager(buildSignatureKeyInfoGeneratorManager());
+			CriteriaSet criteria = new CriteriaSet(new SignatureSigningConfigurationCriterion(signingConfiguration));
+			try {
+				SignatureSigningParameters parameters = resolver.resolveSingle(criteria);
+				Assert.notNull(parameters, "Failed to resolve any signing credential");
+				return parameters;
+			}
+			catch (Exception ex) {
+				throw new Saml2Exception(ex);
+			}
+		}
+
+		private NamedKeyInfoGeneratorManager buildSignatureKeyInfoGeneratorManager() {
+			final NamedKeyInfoGeneratorManager namedManager = new NamedKeyInfoGeneratorManager();
+
+			namedManager.setUseDefaultManager(true);
+			final KeyInfoGeneratorManager defaultManager = namedManager.getDefaultManager();
+
+			// Generator for X509Credentials
+			final X509KeyInfoGeneratorFactory x509Factory = new X509KeyInfoGeneratorFactory();
+			x509Factory.setEmitEntityCertificate(true);
+			x509Factory.setEmitEntityCertificateChain(true);
+
+			defaultManager.registerFactory(x509Factory);
+
+			return namedManager;
+		}
+
+		private List<Credential> resolveSigningCredentials() {
+			List<Credential> credentials = new ArrayList<>();
+			for (Saml2X509Credential x509Credential : this.credentials) {
+				X509Certificate certificate = x509Credential.getCertificate();
+				PrivateKey privateKey = x509Credential.getPrivateKey();
+				BasicCredential credential = CredentialSupport.getSimpleCredential(certificate, privateKey);
+				credential.setUsageType(UsageType.SIGNING);
+				credentials.add(credential);
+			}
+			return credentials;
+		}
+
+	}
+
+	static final class OpenSaml4VerificationConfigurer implements VerificationConfigurer {
+
+		private final Collection<Saml2X509Credential> credentials;
+
+		private String entityId;
+
+		OpenSaml4VerificationConfigurer(Collection<Saml2X509Credential> credentials) {
+			this.credentials = credentials;
+		}
+
+		@Override
+		public VerificationConfigurer entityId(String entityId) {
+			this.entityId = entityId;
+			return this;
+		}
+
+		private SignatureTrustEngine trustEngine(Collection<Saml2X509Credential> keys) {
+			Set<Credential> credentials = new HashSet<>();
+			for (Saml2X509Credential key : keys) {
+				BasicX509Credential cred = new BasicX509Credential(key.getCertificate());
+				cred.setUsageType(UsageType.SIGNING);
+				cred.setEntityId(this.entityId);
+				credentials.add(cred);
+			}
+			CredentialResolver credentialsResolver = new CollectionCredentialResolver(credentials);
+			return new ExplicitKeySignatureTrustEngine(credentialsResolver,
+					DefaultSecurityConfigurationBootstrap.buildBasicInlineKeyInfoCredentialResolver());
+		}
+
+		private CriteriaSet verificationCriteria(Issuer issuer) {
+			return new CriteriaSet(new EvaluableEntityIDCredentialCriterion(new EntityIdCriterion(issuer.getValue())),
+					new EvaluableProtocolRoleDescriptorCriterion(new ProtocolCriterion(SAMLConstants.SAML20P_NS)),
+					new EvaluableUsageCredentialCriterion(new UsageCriterion(UsageType.SIGNING)));
+		}
+
+		@Override
+		public Collection<Saml2Error> verify(SignableXMLObject signable) {
+			if (signable instanceof StatusResponseType response) {
+				return verifySignature(response.getID(), response.getIssuer(), response.getSignature());
+			}
+			if (signable instanceof RequestAbstractType request) {
+				return verifySignature(request.getID(), request.getIssuer(), request.getSignature());
+			}
+			if (signable instanceof Assertion assertion) {
+				return verifySignature(assertion.getID(), assertion.getIssuer(), assertion.getSignature());
+			}
+			throw new Saml2Exception("Unsupported object of type: " + signable.getClass().getName());
+		}
+
+		private Collection<Saml2Error> verifySignature(String id, Issuer issuer, Signature signature) {
+			SignatureTrustEngine trustEngine = trustEngine(this.credentials);
+			CriteriaSet criteria = verificationCriteria(issuer);
+			Collection<Saml2Error> errors = new ArrayList<>();
+			SAMLSignatureProfileValidator profileValidator = new SAMLSignatureProfileValidator();
+			try {
+				profileValidator.validate(signature);
+			}
+			catch (Exception ex) {
+				errors.add(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+						"Invalid signature for object [" + id + "]: "));
+			}
+
+			try {
+				if (!trustEngine.validate(signature, criteria)) {
+					errors.add(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+							"Invalid signature for object [" + id + "]"));
+				}
+			}
+			catch (Exception ex) {
+				errors.add(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+						"Invalid signature for object [" + id + "]: "));
+			}
+
+			return errors;
+		}
+
+		@Override
+		public Collection<Saml2Error> verify(RedirectParameters parameters) {
+			SignatureTrustEngine trustEngine = trustEngine(this.credentials);
+			CriteriaSet criteria = verificationCriteria(parameters.getIssuer());
+			if (parameters.getAlgorithm() == null) {
+				return Collections.singletonList(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+						"Missing signature algorithm for object [" + parameters.getId() + "]"));
+			}
+			if (!parameters.hasSignature()) {
+				return Collections.singletonList(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+						"Missing signature for object [" + parameters.getId() + "]"));
+			}
+			Collection<Saml2Error> errors = new ArrayList<>();
+			String algorithmUri = parameters.getAlgorithm();
+			try {
+				if (!trustEngine.validate(parameters.getSignature(), parameters.getContent(), algorithmUri, criteria,
+						null)) {
+					errors.add(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+							"Invalid signature for object [" + parameters.getId() + "]"));
+				}
+			}
+			catch (Exception ex) {
+				errors.add(new Saml2Error(Saml2ErrorCodes.INVALID_SIGNATURE,
+						"Invalid signature for object [" + parameters.getId() + "]: "));
+			}
+			return errors;
+		}
+
+	}
+
+	static final class OpenSaml4DecryptionConfigurer implements DecryptionConfigurer {
+
+		private static final EncryptedKeyResolver encryptedKeyResolver = new ChainingEncryptedKeyResolver(
+				Arrays.asList(new InlineEncryptedKeyResolver(), new EncryptedElementTypeEncryptedKeyResolver(),
+						new SimpleRetrievalMethodEncryptedKeyResolver()));
+
+		private final Decrypter decrypter;
+
+		OpenSaml4DecryptionConfigurer(Collection<Saml2X509Credential> decryptionCredentials) {
+			this.decrypter = decrypter(decryptionCredentials);
+		}
+
+		private static Decrypter decrypter(Collection<Saml2X509Credential> decryptionCredentials) {
+			Collection<Credential> credentials = new ArrayList<>();
+			for (Saml2X509Credential key : decryptionCredentials) {
+				Credential cred = CredentialSupport.getSimpleCredential(key.getCertificate(), key.getPrivateKey());
+				credentials.add(cred);
+			}
+			KeyInfoCredentialResolver resolver = new CollectionKeyInfoCredentialResolver(credentials);
+			Decrypter decrypter = new Decrypter(null, resolver, encryptedKeyResolver);
+			decrypter.setRootInNewDocument(true);
+			return decrypter;
+		}
+
+		@Override
+		public void decrypt(XMLObject object) {
+			if (object instanceof Response response) {
+				decryptResponse(response);
+				return;
+			}
+			if (object instanceof Assertion assertion) {
+				decryptAssertion(assertion);
+			}
+			if (object instanceof LogoutRequest request) {
+				decryptLogoutRequest(request);
+			}
+		}
+
+		/*
+		 * The methods that follow are adapted from OpenSAML's {@link DecryptAssertions},
+		 * {@link DecryptNameIDs}, and {@link DecryptAttributes}.
+		 *
+		 * <p>The reason that these OpenSAML classes are not used directly is because they
+		 * reference {@link javax.servlet.http.HttpServletRequest} which is a lower
+		 * Servlet API version than what Spring Security SAML uses.
+		 *
+		 * If OpenSAML 5 updates to {@link jakarta.servlet.http.HttpServletRequest}, then
+		 * this arrangement can be revisited.
+		 */
+
+		private void decryptResponse(Response response) {
+			Collection<Assertion> decrypteds = new ArrayList<>();
+			Collection<EncryptedAssertion> encrypteds = new ArrayList<>();
+
+			int count = 0;
+			int size = response.getEncryptedAssertions().size();
+			for (EncryptedAssertion encrypted : response.getEncryptedAssertions()) {
+				logger.trace(String.format("Decrypting EncryptedAssertion (%d/%d) in Response [%s]", count, size,
+						response.getID()));
+				try {
+					Assertion decrypted = this.decrypter.decrypt(encrypted);
+					if (decrypted != null) {
+						encrypteds.add(encrypted);
+						decrypteds.add(decrypted);
+					}
+					count++;
+				}
+				catch (DecryptionException ex) {
+					throw new Saml2Exception(ex);
+				}
+			}
+
+			response.getEncryptedAssertions().removeAll(encrypteds);
+			response.getAssertions().addAll(decrypteds);
+
+			// Re-marshall the response so that any ID attributes within the decrypted
+			// Assertions
+			// will have their ID-ness re-established at the DOM level.
+			if (!decrypteds.isEmpty()) {
+				try {
+					XMLObjectSupport.marshall(response);
+				}
+				catch (final MarshallingException ex) {
+					throw new Saml2Exception(ex);
+				}
+			}
+		}
+
+		private void decryptAssertion(Assertion assertion) {
+			for (AttributeStatement statement : assertion.getAttributeStatements()) {
+				decryptAttributes(statement);
+			}
+			decryptSubject(assertion.getSubject());
+			if (assertion.getConditions() != null) {
+				for (Condition c : assertion.getConditions().getConditions()) {
+					if (!(c instanceof DelegationRestrictionType delegation)) {
+						continue;
+					}
+					for (Delegate d : delegation.getDelegates()) {
+						if (d.getEncryptedID() != null) {
+							try {
+								NameID decrypted = (NameID) this.decrypter.decrypt(d.getEncryptedID());
+								if (decrypted != null) {
+									d.setNameID(decrypted);
+									d.setEncryptedID(null);
+								}
+							}
+							catch (DecryptionException ex) {
+								throw new Saml2Exception(ex);
+							}
+						}
+					}
+				}
+			}
+		}
+
+		private void decryptAttributes(AttributeStatement statement) {
+			Collection<Attribute> decrypteds = new ArrayList<>();
+			Collection<EncryptedAttribute> encrypteds = new ArrayList<>();
+			for (EncryptedAttribute encrypted : statement.getEncryptedAttributes()) {
+				try {
+					Attribute decrypted = this.decrypter.decrypt(encrypted);
+					if (decrypted != null) {
+						encrypteds.add(encrypted);
+						decrypteds.add(decrypted);
+					}
+				}
+				catch (Exception ex) {
+					throw new Saml2Exception(ex);
+				}
+			}
+			statement.getEncryptedAttributes().removeAll(encrypteds);
+			statement.getAttributes().addAll(decrypteds);
+		}
+
+		private void decryptSubject(Subject subject) {
+			if (subject != null) {
+				if (subject.getEncryptedID() != null) {
+					try {
+						NameID decrypted = (NameID) this.decrypter.decrypt(subject.getEncryptedID());
+						if (decrypted != null) {
+							subject.setNameID(decrypted);
+							subject.setEncryptedID(null);
+						}
+					}
+					catch (final DecryptionException ex) {
+						throw new Saml2Exception(ex);
+					}
+				}
+
+				for (final SubjectConfirmation sc : subject.getSubjectConfirmations()) {
+					if (sc.getEncryptedID() != null) {
+						try {
+							NameID decrypted = (NameID) this.decrypter.decrypt(sc.getEncryptedID());
+							if (decrypted != null) {
+								sc.setNameID(decrypted);
+								sc.setEncryptedID(null);
+							}
+						}
+						catch (final DecryptionException ex) {
+							throw new Saml2Exception(ex);
+						}
+					}
+				}
+			}
+		}
+
+		private void decryptLogoutRequest(LogoutRequest request) {
+			if (request.getEncryptedID() != null) {
+				try {
+					NameID decrypted = (NameID) this.decrypter.decrypt(request.getEncryptedID());
+					if (decrypted != null) {
+						request.setNameID(decrypted);
+						request.setEncryptedID(null);
+					}
+				}
+				catch (DecryptionException ex) {
+					throw new Saml2Exception(ex);
+				}
+			}
+		}
+
+	}
+
+}

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/OpenSamlMetadataResolver.java

@@ -23,13 +23,8 @@ import java.util.Collection;
 import java.util.List;
 import java.util.function.Consumer;
 
-import javax.xml.namespace.QName;
-
-import net.shibboleth.utilities.java.support.xml.SerializeSupport;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.opensaml.core.xml.XMLObjectBuilder;
-import org.opensaml.core.xml.config.XMLObjectProviderRegistrySupport;
 import org.opensaml.saml.common.xml.SAMLConstants;
 import org.opensaml.saml.saml2.metadata.AssertionConsumerService;
 import org.opensaml.saml.saml2.metadata.EntitiesDescriptor;
@@ -38,13 +33,10 @@ import org.opensaml.saml.saml2.metadata.KeyDescriptor;
 import org.opensaml.saml.saml2.metadata.NameIDFormat;
 import org.opensaml.saml.saml2.metadata.SPSSODescriptor;
 import org.opensaml.saml.saml2.metadata.SingleLogoutService;
-import org.opensaml.saml.saml2.metadata.impl.EntitiesDescriptorMarshaller;
-import org.opensaml.saml.saml2.metadata.impl.EntityDescriptorMarshaller;
 import org.opensaml.security.credential.UsageType;
 import org.opensaml.xmlsec.signature.KeyInfo;
 import org.opensaml.xmlsec.signature.X509Certificate;
 import org.opensaml.xmlsec.signature.X509Data;
-import org.w3c.dom.Element;
 
 import org.springframework.security.saml2.Saml2Exception;
 import org.springframework.security.saml2.core.OpenSamlInitializationService;
@@ -60,7 +52,10 @@ import org.springframework.util.Assert;
  * @author Jakub Kubrynski
  * @author Josh Cummings
  * @since 5.4
+ * @deprecated Please use version-specific {@link Saml2MetadataResolver} instead, for
+ * example {@code OpenSaml4MetadataResolver}
  */
+@Deprecated
 public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 
 	static {
@@ -69,9 +64,7 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 
 	private final Log logger = LogFactory.getLog(this.getClass());
 
-	private final EntityDescriptorMarshaller entityDescriptorMarshaller;
-
-	private final EntitiesDescriptorMarshaller entitiesDescriptorMarshaller;
+	private OpenSamlOperations saml = new OpenSaml4Template();
 
 	private Consumer<EntityDescriptorParameters> entityDescriptorCustomizer = (parameters) -> {
 	};
@@ -81,14 +74,10 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	private boolean signMetadata = false;
 
 	public OpenSamlMetadataResolver() {
-		this.entityDescriptorMarshaller = (EntityDescriptorMarshaller) XMLObjectProviderRegistrySupport
-			.getMarshallerFactory()
-			.getMarshaller(EntityDescriptor.DEFAULT_ELEMENT_NAME);
-		Assert.notNull(this.entityDescriptorMarshaller, "entityDescriptorMarshaller cannot be null");
-		this.entitiesDescriptorMarshaller = (EntitiesDescriptorMarshaller) XMLObjectProviderRegistrySupport
-			.getMarshallerFactory()
-			.getMarshaller(EntitiesDescriptor.DEFAULT_ELEMENT_NAME);
-		Assert.notNull(this.entitiesDescriptorMarshaller, "entitiesDescriptorMarshaller cannot be null");
+	}
+
+	OpenSamlMetadataResolver(OpenSamlOperations saml) {
+		this.saml = saml;
 	}
 
 	@Override
@@ -106,19 +95,21 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 		if (entityDescriptors.size() == 1) {
 			return serialize(entityDescriptors.iterator().next());
 		}
-		EntitiesDescriptor entities = build(EntitiesDescriptor.DEFAULT_ELEMENT_NAME);
+		EntitiesDescriptor entities = this.saml.build(EntitiesDescriptor.DEFAULT_ELEMENT_NAME);
 		entities.getEntityDescriptors().addAll(entityDescriptors);
 		return serialize(entities);
 	}
 
 	private EntityDescriptor entityDescriptor(RelyingPartyRegistration registration) {
-		EntityDescriptor entityDescriptor = build(EntityDescriptor.DEFAULT_ELEMENT_NAME);
+		EntityDescriptor entityDescriptor = this.saml.build(EntityDescriptor.DEFAULT_ELEMENT_NAME);
 		entityDescriptor.setEntityID(registration.getEntityId());
 		SPSSODescriptor spSsoDescriptor = buildSpSsoDescriptor(registration);
 		entityDescriptor.getRoleDescriptors(SPSSODescriptor.DEFAULT_ELEMENT_NAME).add(spSsoDescriptor);
 		this.entityDescriptorCustomizer.accept(new EntityDescriptorParameters(entityDescriptor, registration));
 		if (this.signMetadata) {
-			return OpenSamlSigningUtils.sign(entityDescriptor, registration);
+			return this.saml.withSigningKeys(registration.getSigningX509Credentials())
+				.algorithms(registration.getAssertingPartyMetadata().getSigningAlgorithms())
+				.sign(entityDescriptor);
 		}
 		else {
 			this.logger.trace("Did not sign metadata since `signMetadata` is `false`");
@@ -148,7 +139,7 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	}
 
 	private SPSSODescriptor buildSpSsoDescriptor(RelyingPartyRegistration registration) {
-		SPSSODescriptor spSsoDescriptor = build(SPSSODescriptor.DEFAULT_ELEMENT_NAME);
+		SPSSODescriptor spSsoDescriptor = this.saml.build(SPSSODescriptor.DEFAULT_ELEMENT_NAME);
 		spSsoDescriptor.addSupportedProtocol(SAMLConstants.SAML20P_NS);
 		spSsoDescriptor.getKeyDescriptors()
 			.addAll(buildKeys(registration.getSigningX509Credentials(), UsageType.SIGNING));
@@ -176,10 +167,10 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	}
 
 	private KeyDescriptor buildKeyDescriptor(UsageType usageType, java.security.cert.X509Certificate certificate) {
-		KeyDescriptor keyDescriptor = build(KeyDescriptor.DEFAULT_ELEMENT_NAME);
-		KeyInfo keyInfo = build(KeyInfo.DEFAULT_ELEMENT_NAME);
-		X509Certificate x509Certificate = build(X509Certificate.DEFAULT_ELEMENT_NAME);
-		X509Data x509Data = build(X509Data.DEFAULT_ELEMENT_NAME);
+		KeyDescriptor keyDescriptor = this.saml.build(KeyDescriptor.DEFAULT_ELEMENT_NAME);
+		KeyInfo keyInfo = this.saml.build(KeyInfo.DEFAULT_ELEMENT_NAME);
+		X509Certificate x509Certificate = this.saml.build(X509Certificate.DEFAULT_ELEMENT_NAME);
+		X509Data x509Data = this.saml.build(X509Data.DEFAULT_ELEMENT_NAME);
 		try {
 			x509Certificate.setValue(new String(Base64.getEncoder().encode(certificate.getEncoded())));
 		}
@@ -194,7 +185,8 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	}
 
 	private AssertionConsumerService buildAssertionConsumerService(RelyingPartyRegistration registration) {
-		AssertionConsumerService assertionConsumerService = build(AssertionConsumerService.DEFAULT_ELEMENT_NAME);
+		AssertionConsumerService assertionConsumerService = this.saml
+			.build(AssertionConsumerService.DEFAULT_ELEMENT_NAME);
 		assertionConsumerService.setLocation(registration.getAssertionConsumerServiceLocation());
 		assertionConsumerService.setBinding(registration.getAssertionConsumerServiceBinding().getUrn());
 		assertionConsumerService.setIndex(1);
@@ -203,7 +195,7 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 
 	private SingleLogoutService buildSingleLogoutService(RelyingPartyRegistration registration,
 			Saml2MessageBinding binding) {
-		SingleLogoutService singleLogoutService = build(SingleLogoutService.DEFAULT_ELEMENT_NAME);
+		SingleLogoutService singleLogoutService = this.saml.build(SingleLogoutService.DEFAULT_ELEMENT_NAME);
 		singleLogoutService.setLocation(registration.getSingleLogoutServiceLocation());
 		singleLogoutService.setResponseLocation(registration.getSingleLogoutServiceResponseLocation());
 		singleLogoutService.setBinding(binding.getUrn());
@@ -211,44 +203,17 @@ public final class OpenSamlMetadataResolver implements Saml2MetadataResolver {
 	}
 
 	private NameIDFormat buildNameIDFormat(RelyingPartyRegistration registration) {
-		NameIDFormat nameIdFormat = build(NameIDFormat.DEFAULT_ELEMENT_NAME);
+		NameIDFormat nameIdFormat = this.saml.build(NameIDFormat.DEFAULT_ELEMENT_NAME);
 		nameIdFormat.setURI(registration.getNameIdFormat());
 		return nameIdFormat;
 	}
 
-	@SuppressWarnings("unchecked")
-	private <T> T build(QName elementName) {
-		XMLObjectBuilder<?> builder = XMLObjectProviderRegistrySupport.getBuilderFactory().getBuilder(elementName);
-		if (builder == null) {
-			throw new Saml2Exception("Unable to resolve Builder for " + elementName);
-		}
-		return (T) builder.buildObject(elementName);
-	}
-
 	private String serialize(EntityDescriptor entityDescriptor) {
-		try {
-			Element element = this.entityDescriptorMarshaller.marshall(entityDescriptor);
-			if (this.usePrettyPrint) {
-				return SerializeSupport.prettyPrintXML(element);
-			}
-			return SerializeSupport.nodeToString(element);
-		}
-		catch (Exception ex) {
-			throw new Saml2Exception(ex);
-		}
+		return this.saml.serialize(entityDescriptor).prettyPrint(this.usePrettyPrint).serialize();
 	}
 
 	private String serialize(EntitiesDescriptor entities) {
-		try {
-			Element element = this.entitiesDescriptorMarshaller.marshall(entities);
-			if (this.usePrettyPrint) {
-				return SerializeSupport.prettyPrintXML(element);
-			}
-			return SerializeSupport.nodeToString(element);
-		}
-		catch (Exception ex) {
-			throw new Saml2Exception(ex);
-		}
+		return this.saml.serialize(entities).prettyPrint(this.usePrettyPrint).serialize();
 	}
 
 	/**

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/OpenSamlOperations.java

@@ -0,0 +1,184 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.metadata;
+
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+import javax.xml.namespace.QName;
+
+import org.opensaml.core.xml.XMLObject;
+import org.opensaml.saml.saml2.core.Issuer;
+import org.opensaml.saml.saml2.core.RequestAbstractType;
+import org.opensaml.saml.saml2.core.StatusResponseType;
+import org.opensaml.xmlsec.signature.SignableXMLObject;
+import org.w3c.dom.Element;
+
+import org.springframework.security.saml2.core.Saml2Error;
+import org.springframework.security.saml2.core.Saml2ParameterNames;
+import org.springframework.security.saml2.core.Saml2X509Credential;
+import org.springframework.web.util.UriComponentsBuilder;
+
+interface OpenSamlOperations {
+
+	<T extends XMLObject> T build(QName elementName);
+
+	<T extends XMLObject> T deserialize(String serialized);
+
+	<T extends XMLObject> T deserialize(InputStream serialized);
+
+	SerializationConfigurer<?> serialize(XMLObject object);
+
+	SerializationConfigurer<?> serialize(Element element);
+
+	SignatureConfigurer<?> withSigningKeys(Collection<Saml2X509Credential> credentials);
+
+	VerificationConfigurer withVerificationKeys(Collection<Saml2X509Credential> credentials);
+
+	DecryptionConfigurer withDecryptionKeys(Collection<Saml2X509Credential> credentials);
+
+	interface SerializationConfigurer<B extends SerializationConfigurer<B>> {
+
+		B prettyPrint(boolean pretty);
+
+		String serialize();
+
+	}
+
+	interface SignatureConfigurer<B extends SignatureConfigurer<B>> {
+
+		B algorithms(List<String> algs);
+
+		<O extends SignableXMLObject> O sign(O object);
+
+		Map<String, String> sign(Map<String, String> params);
+
+	}
+
+	interface VerificationConfigurer {
+
+		VerificationConfigurer entityId(String entityId);
+
+		Collection<Saml2Error> verify(SignableXMLObject signable);
+
+		Collection<Saml2Error> verify(VerificationConfigurer.RedirectParameters parameters);
+
+		final class RedirectParameters {
+
+			private final String id;
+
+			private final Issuer issuer;
+
+			private final String algorithm;
+
+			private final byte[] signature;
+
+			private final byte[] content;
+
+			RedirectParameters(Map<String, String> parameters, String parametersQuery, RequestAbstractType request) {
+				this.id = request.getID();
+				this.issuer = request.getIssuer();
+				this.algorithm = parameters.get(Saml2ParameterNames.SIG_ALG);
+				if (parameters.get(Saml2ParameterNames.SIGNATURE) != null) {
+					this.signature = Saml2Utils.samlDecode(parameters.get(Saml2ParameterNames.SIGNATURE));
+				}
+				else {
+					this.signature = null;
+				}
+				Map<String, String> queryParams = UriComponentsBuilder.newInstance()
+					.query(parametersQuery)
+					.build(true)
+					.getQueryParams()
+					.toSingleValueMap();
+				String relayState = parameters.get(Saml2ParameterNames.RELAY_STATE);
+				this.content = getContent(Saml2ParameterNames.SAML_REQUEST, relayState, queryParams);
+			}
+
+			RedirectParameters(Map<String, String> parameters, String parametersQuery, StatusResponseType response) {
+				this.id = response.getID();
+				this.issuer = response.getIssuer();
+				this.algorithm = parameters.get(Saml2ParameterNames.SIG_ALG);
+				if (parameters.get(Saml2ParameterNames.SIGNATURE) != null) {
+					this.signature = Saml2Utils.samlDecode(parameters.get(Saml2ParameterNames.SIGNATURE));
+				}
+				else {
+					this.signature = null;
+				}
+				Map<String, String> queryParams = UriComponentsBuilder.newInstance()
+					.query(parametersQuery)
+					.build(true)
+					.getQueryParams()
+					.toSingleValueMap();
+				String relayState = parameters.get(Saml2ParameterNames.RELAY_STATE);
+				this.content = getContent(Saml2ParameterNames.SAML_RESPONSE, relayState, queryParams);
+			}
+
+			static byte[] getContent(String samlObject, String relayState, final Map<String, String> queryParams) {
+				if (Objects.nonNull(relayState)) {
+					return String
+						.format("%s=%s&%s=%s&%s=%s", samlObject, queryParams.get(samlObject),
+								Saml2ParameterNames.RELAY_STATE, queryParams.get(Saml2ParameterNames.RELAY_STATE),
+								Saml2ParameterNames.SIG_ALG, queryParams.get(Saml2ParameterNames.SIG_ALG))
+						.getBytes(StandardCharsets.UTF_8);
+				}
+				else {
+					return String
+						.format("%s=%s&%s=%s", samlObject, queryParams.get(samlObject), Saml2ParameterNames.SIG_ALG,
+								queryParams.get(Saml2ParameterNames.SIG_ALG))
+						.getBytes(StandardCharsets.UTF_8);
+				}
+			}
+
+			String getId() {
+				return this.id;
+			}
+
+			Issuer getIssuer() {
+				return this.issuer;
+			}
+
+			byte[] getContent() {
+				return this.content;
+			}
+
+			String getAlgorithm() {
+				return this.algorithm;
+			}
+
+			byte[] getSignature() {
+				return this.signature;
+			}
+
+			boolean hasSignature() {
+				return this.signature != null;
+			}
+
+		}
+
+	}
+
+	interface DecryptionConfigurer {
+
+		void decrypt(XMLObject object);
+
+	}
+
+}

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/OpenSamlSigningUtils.java

@@ -1,206 +0,0 @@
-/*
- * Copyright 2002-2024 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.security.saml2.provider.service.metadata;
-
-import java.nio.charset.StandardCharsets;
-import java.security.PrivateKey;
-import java.security.cert.X509Certificate;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-
-import net.shibboleth.utilities.java.support.resolver.CriteriaSet;
-import net.shibboleth.utilities.java.support.xml.SerializeSupport;
-import org.opensaml.core.xml.XMLObject;
-import org.opensaml.core.xml.config.XMLObjectProviderRegistrySupport;
-import org.opensaml.core.xml.io.Marshaller;
-import org.opensaml.core.xml.io.MarshallingException;
-import org.opensaml.saml.security.impl.SAMLMetadataSignatureSigningParametersResolver;
-import org.opensaml.security.SecurityException;
-import org.opensaml.security.credential.BasicCredential;
-import org.opensaml.security.credential.Credential;
-import org.opensaml.security.credential.CredentialSupport;
-import org.opensaml.security.credential.UsageType;
-import org.opensaml.xmlsec.SignatureSigningParameters;
-import org.opensaml.xmlsec.SignatureSigningParametersResolver;
-import org.opensaml.xmlsec.criterion.SignatureSigningConfigurationCriterion;
-import org.opensaml.xmlsec.crypto.XMLSigningUtil;
-import org.opensaml.xmlsec.impl.BasicSignatureSigningConfiguration;
-import org.opensaml.xmlsec.keyinfo.KeyInfoGeneratorManager;
-import org.opensaml.xmlsec.keyinfo.NamedKeyInfoGeneratorManager;
-import org.opensaml.xmlsec.keyinfo.impl.X509KeyInfoGeneratorFactory;
-import org.opensaml.xmlsec.signature.SignableXMLObject;
-import org.opensaml.xmlsec.signature.support.SignatureConstants;
-import org.opensaml.xmlsec.signature.support.SignatureSupport;
-import org.w3c.dom.Element;
-
-import org.springframework.security.saml2.Saml2Exception;
-import org.springframework.security.saml2.core.Saml2ParameterNames;
-import org.springframework.security.saml2.core.Saml2X509Credential;
-import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
-import org.springframework.util.Assert;
-import org.springframework.web.util.UriComponentsBuilder;
-import org.springframework.web.util.UriUtils;
-
-/**
- * Utility methods for signing SAML components with OpenSAML
- *
- * For internal use only.
- *
- * @author Josh Cummings
- * @since 6.3
- */
-final class OpenSamlSigningUtils {
-
-	static String serialize(XMLObject object) {
-		try {
-			Marshaller marshaller = XMLObjectProviderRegistrySupport.getMarshallerFactory().getMarshaller(object);
-			Element element = marshaller.marshall(object);
-			return SerializeSupport.nodeToString(element);
-		}
-		catch (MarshallingException ex) {
-			throw new Saml2Exception(ex);
-		}
-	}
-
-	static <O extends SignableXMLObject> O sign(O object, RelyingPartyRegistration relyingPartyRegistration) {
-		List<String> algorithms = relyingPartyRegistration.getAssertingPartyMetadata().getSigningAlgorithms();
-		List<Credential> credentials = resolveSigningCredentials(relyingPartyRegistration);
-		return sign(object, algorithms, credentials);
-	}
-
-	static <O extends SignableXMLObject> O sign(O object, List<String> algorithms, List<Credential> credentials) {
-		SignatureSigningParameters parameters = resolveSigningParameters(algorithms, credentials);
-		try {
-			SignatureSupport.signObject(object, parameters);
-			return object;
-		}
-		catch (Exception ex) {
-			throw new Saml2Exception(ex);
-		}
-	}
-
-	static QueryParametersPartial sign(RelyingPartyRegistration registration) {
-		return new QueryParametersPartial(registration);
-	}
-
-	private static SignatureSigningParameters resolveSigningParameters(
-			RelyingPartyRegistration relyingPartyRegistration) {
-		List<Credential> credentials = resolveSigningCredentials(relyingPartyRegistration);
-		List<String> algorithms = relyingPartyRegistration.getAssertingPartyMetadata().getSigningAlgorithms();
-		return resolveSigningParameters(algorithms, credentials);
-	}
-
-	private static SignatureSigningParameters resolveSigningParameters(List<String> algorithms,
-			List<Credential> credentials) {
-		List<String> digests = Collections.singletonList(SignatureConstants.ALGO_ID_DIGEST_SHA256);
-		String canonicalization = SignatureConstants.ALGO_ID_C14N_EXCL_OMIT_COMMENTS;
-		SignatureSigningParametersResolver resolver = new SAMLMetadataSignatureSigningParametersResolver();
-		CriteriaSet criteria = new CriteriaSet();
-		BasicSignatureSigningConfiguration signingConfiguration = new BasicSignatureSigningConfiguration();
-		signingConfiguration.setSigningCredentials(credentials);
-		signingConfiguration.setSignatureAlgorithms(algorithms);
-		signingConfiguration.setSignatureReferenceDigestMethods(digests);
-		signingConfiguration.setSignatureCanonicalizationAlgorithm(canonicalization);
-		signingConfiguration.setKeyInfoGeneratorManager(buildSignatureKeyInfoGeneratorManager());
-		criteria.add(new SignatureSigningConfigurationCriterion(signingConfiguration));
-		try {
-			SignatureSigningParameters parameters = resolver.resolveSingle(criteria);
-			Assert.notNull(parameters, "Failed to resolve any signing credential");
-			return parameters;
-		}
-		catch (Exception ex) {
-			throw new Saml2Exception(ex);
-		}
-	}
-
-	private static NamedKeyInfoGeneratorManager buildSignatureKeyInfoGeneratorManager() {
-		final NamedKeyInfoGeneratorManager namedManager = new NamedKeyInfoGeneratorManager();
-
-		namedManager.setUseDefaultManager(true);
-		final KeyInfoGeneratorManager defaultManager = namedManager.getDefaultManager();
-
-		// Generator for X509Credentials
-		final X509KeyInfoGeneratorFactory x509Factory = new X509KeyInfoGeneratorFactory();
-		x509Factory.setEmitEntityCertificate(true);
-		x509Factory.setEmitEntityCertificateChain(true);
-
-		defaultManager.registerFactory(x509Factory);
-
-		return namedManager;
-	}
-
-	private static List<Credential> resolveSigningCredentials(RelyingPartyRegistration relyingPartyRegistration) {
-		List<Credential> credentials = new ArrayList<>();
-		for (Saml2X509Credential x509Credential : relyingPartyRegistration.getSigningX509Credentials()) {
-			X509Certificate certificate = x509Credential.getCertificate();
-			PrivateKey privateKey = x509Credential.getPrivateKey();
-			BasicCredential credential = CredentialSupport.getSimpleCredential(certificate, privateKey);
-			credential.setEntityId(relyingPartyRegistration.getEntityId());
-			credential.setUsageType(UsageType.SIGNING);
-			credentials.add(credential);
-		}
-		return credentials;
-	}
-
-	private OpenSamlSigningUtils() {
-
-	}
-
-	static class QueryParametersPartial {
-
-		final RelyingPartyRegistration registration;
-
-		final Map<String, String> components = new LinkedHashMap<>();
-
-		QueryParametersPartial(RelyingPartyRegistration registration) {
-			this.registration = registration;
-		}
-
-		QueryParametersPartial param(String key, String value) {
-			this.components.put(key, value);
-			return this;
-		}
-
-		Map<String, String> parameters() {
-			SignatureSigningParameters parameters = resolveSigningParameters(this.registration);
-			Credential credential = parameters.getSigningCredential();
-			String algorithmUri = parameters.getSignatureAlgorithm();
-			this.components.put(Saml2ParameterNames.SIG_ALG, algorithmUri);
-			UriComponentsBuilder builder = UriComponentsBuilder.newInstance();
-			for (Map.Entry<String, String> component : this.components.entrySet()) {
-				builder.queryParam(component.getKey(),
-						UriUtils.encode(component.getValue(), StandardCharsets.ISO_8859_1));
-			}
-			String queryString = builder.build(true).toString().substring(1);
-			try {
-				byte[] rawSignature = XMLSigningUtil.signWithURI(credential, algorithmUri,
-						queryString.getBytes(StandardCharsets.UTF_8));
-				String b64Signature = Saml2Utils.samlEncode(rawSignature);
-				this.components.put(Saml2ParameterNames.SIGNATURE, b64Signature);
-			}
-			catch (SecurityException ex) {
-				throw new Saml2Exception(ex);
-			}
-			return this.components;
-		}
-
-	}
-
-}

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/metadata/Saml2Utils.java

@@ -19,6 +19,7 @@ package org.springframework.security.saml2.provider.service.metadata;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 import java.util.Base64;
 import java.util.zip.Deflater;
 import java.util.zip.DeflaterOutputStream;
@@ -28,7 +29,11 @@ import java.util.zip.InflaterOutputStream;
 import org.springframework.security.saml2.Saml2Exception;
 
 /**
- * @since 6.3
+ * Utility methods for working with serialized SAML messages.
+ *
+ * For internal use only.
+ *
+ * @author Josh Cummings
  */
 final class Saml2Utils {
 
@@ -69,4 +74,123 @@ final class Saml2Utils {
 		}
 	}
 
+	static EncodingConfigurer withDecoded(String decoded) {
+		return new EncodingConfigurer(decoded);
+	}
+
+	static DecodingConfigurer withEncoded(String encoded) {
+		return new DecodingConfigurer(encoded);
+	}
+
+	static final class EncodingConfigurer {
+
+		private final String decoded;
+
+		private boolean deflate;
+
+		private EncodingConfigurer(String decoded) {
+			this.decoded = decoded;
+		}
+
+		EncodingConfigurer deflate(boolean deflate) {
+			this.deflate = deflate;
+			return this;
+		}
+
+		String encode() {
+			byte[] bytes = (this.deflate) ? Saml2Utils.samlDeflate(this.decoded)
+					: this.decoded.getBytes(StandardCharsets.UTF_8);
+			return Saml2Utils.samlEncode(bytes);
+		}
+
+	}
+
+	static final class DecodingConfigurer {
+
+		private static final Base64Checker BASE_64_CHECKER = new Base64Checker();
+
+		private final String encoded;
+
+		private boolean inflate;
+
+		private boolean requireBase64;
+
+		private DecodingConfigurer(String encoded) {
+			this.encoded = encoded;
+		}
+
+		DecodingConfigurer inflate(boolean inflate) {
+			this.inflate = inflate;
+			return this;
+		}
+
+		DecodingConfigurer requireBase64(boolean requireBase64) {
+			this.requireBase64 = requireBase64;
+			return this;
+		}
+
+		String decode() {
+			if (this.requireBase64) {
+				BASE_64_CHECKER.checkAcceptable(this.encoded);
+			}
+			byte[] bytes = Saml2Utils.samlDecode(this.encoded);
+			return (this.inflate) ? Saml2Utils.samlInflate(bytes) : new String(bytes, StandardCharsets.UTF_8);
+		}
+
+		static class Base64Checker {
+
+			private static final int[] values = genValueMapping();
+
+			Base64Checker() {
+
+			}
+
+			private static int[] genValueMapping() {
+				byte[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+					.getBytes(StandardCharsets.ISO_8859_1);
+
+				int[] values = new int[256];
+				Arrays.fill(values, -1);
+				for (int i = 0; i < alphabet.length; i++) {
+					values[alphabet[i] & 0xff] = i;
+				}
+				return values;
+			}
+
+			boolean isAcceptable(String s) {
+				int goodChars = 0;
+				int lastGoodCharVal = -1;
+
+				// count number of characters from Base64 alphabet
+				for (int i = 0; i < s.length(); i++) {
+					int val = values[0xff & s.charAt(i)];
+					if (val != -1) {
+						lastGoodCharVal = val;
+						goodChars++;
+					}
+				}
+
+				// in cases of an incomplete final chunk, ensure the unused bits are zero
+				switch (goodChars % 4) {
+					case 0:
+						return true;
+					case 2:
+						return (lastGoodCharVal & 0b1111) == 0;
+					case 3:
+						return (lastGoodCharVal & 0b11) == 0;
+					default:
+						return false;
+				}
+			}
+
+			void checkAcceptable(String ins) {
+				if (!isAcceptable(ins)) {
+					throw new IllegalArgumentException("Failed to decode SAMLResponse");
+				}
+			}
+
+		}
+
+	}
+
 }

saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/metadata/OpenSaml4MetadataResolverTests.java

@@ -0,0 +1,185 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.metadata;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.security.saml2.core.TestSaml2X509Credentials;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
+import org.springframework.security.saml2.provider.service.registration.Saml2MessageBinding;
+import org.springframework.security.saml2.provider.service.registration.TestRelyingPartyRegistrations;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link OpenSaml4MetadataResolver}
+ */
+public class OpenSaml4MetadataResolverTests {
+
+	@Test
+	public void resolveWhenRelyingPartyThenMetadataMatches() {
+		RelyingPartyRegistration relyingPartyRegistration = TestRelyingPartyRegistrations.full()
+			.assertionConsumerServiceBinding(Saml2MessageBinding.REDIRECT)
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		String metadata = OpenSaml4MetadataResolver.resolve(relyingPartyRegistration);
+		assertThat(metadata).contains("<md:EntityDescriptor")
+			.contains("entityID=\"rp-entity-id\"")
+			.contains("<md:KeyDescriptor use=\"signing\">")
+			.contains("<md:KeyDescriptor use=\"encryption\">")
+			.contains("<ds:X509Certificate>MIICgTCCAeoCCQCuVzyqFgMSyDANBgkqhkiG9w0BAQsFADCBhDELMAkGA1UEBh")
+			.contains("Binding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect\"")
+			.contains("Location=\"https://rp.example.org/acs\" index=\"1\"")
+			.contains("ResponseLocation=\"https://rp.example.org/logout/saml2/response\"");
+	}
+
+	@Test
+	public void resolveWhenRelyingPartyAndSignMetadataSetThenMetadataMatches() {
+		RelyingPartyRegistration relyingPartyRegistration = TestRelyingPartyRegistrations.full()
+			.assertionConsumerServiceBinding(Saml2MessageBinding.REDIRECT)
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		OpenSaml4MetadataResolver.setSignMetadata(true);
+		String metadata = OpenSaml4MetadataResolver.resolve(relyingPartyRegistration);
+		assertThat(metadata).contains("<md:EntityDescriptor")
+			.contains("entityID=\"rp-entity-id\"")
+			.contains("<md:KeyDescriptor use=\"signing\">")
+			.contains("<md:KeyDescriptor use=\"encryption\">")
+			.contains("<ds:X509Certificate>MIICgTCCAeoCCQCuVzyqFgMSyDANBgkqhkiG9w0BAQsFADCBhDELMAkGA1UEBh")
+			.contains("Binding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect\"")
+			.contains("Location=\"https://rp.example.org/acs\" index=\"1\"")
+			.contains("ResponseLocation=\"https://rp.example.org/logout/saml2/response\"")
+			.contains("Signature xmlns:ds=\"http://www.w3.org/2000/09/xmldsig#\"")
+			.contains("CanonicalizationMethod Algorithm=\"http://www.w3.org/2001/10/xml-exc-c14n#")
+			.contains("SignatureMethod Algorithm=\"http://www.w3.org/2001/04/xmldsig-more#rsa-sha256")
+			.contains("Reference URI=\"\"")
+			.contains("Transform Algorithm=\"http://www.w3.org/2000/09/xmldsig#enveloped-signature")
+			.contains("Transform Algorithm=\"http://www.w3.org/2001/10/xml-exc-c14n#\"")
+			.contains("DigestMethod Algorithm=\"http://www.w3.org/2001/04/xmlenc#sha256\"")
+			.contains("DigestValue")
+			.contains("SignatureValue");
+	}
+
+	@Test
+	public void resolveWhenRelyingPartyNoCredentialsThenMetadataMatches() {
+		RelyingPartyRegistration relyingPartyRegistration = TestRelyingPartyRegistrations.noCredentials()
+			.assertingPartyDetails((party) -> party
+				.verificationX509Credentials((c) -> c.add(TestSaml2X509Credentials.relyingPartyVerifyingCredential())))
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		String metadata = OpenSaml4MetadataResolver.resolve(relyingPartyRegistration);
+		assertThat(metadata).contains("<md:EntityDescriptor")
+			.contains("entityID=\"rp-entity-id\"")
+			.doesNotContain("<md:KeyDescriptor use=\"signing\">")
+			.doesNotContain("<md:KeyDescriptor use=\"encryption\">")
+			.contains("Binding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST\"")
+			.contains("Location=\"https://rp.example.org/acs\" index=\"1\"")
+			.contains("ResponseLocation=\"https://rp.example.org/logout/saml2/response\"");
+	}
+
+	@Test
+	public void resolveWhenRelyingPartyNameIDFormatThenMetadataMatches() {
+		RelyingPartyRegistration relyingPartyRegistration = TestRelyingPartyRegistrations.full()
+			.nameIdFormat("format")
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		String metadata = OpenSaml4MetadataResolver.resolve(relyingPartyRegistration);
+		assertThat(metadata).contains("<md:NameIDFormat>format</md:NameIDFormat>");
+	}
+
+	@Test
+	public void resolveWhenRelyingPartyNoLogoutThenMetadataMatches() {
+		RelyingPartyRegistration relyingPartyRegistration = TestRelyingPartyRegistrations.full()
+			.singleLogoutServiceLocation(null)
+			.nameIdFormat("format")
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		String metadata = OpenSaml4MetadataResolver.resolve(relyingPartyRegistration);
+		assertThat(metadata).doesNotContain("ResponseLocation");
+	}
+
+	@Test
+	public void resolveWhenEntityDescriptorCustomizerThenUses() {
+		RelyingPartyRegistration relyingPartyRegistration = TestRelyingPartyRegistrations.full()
+			.entityId("originalEntityId")
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		OpenSaml4MetadataResolver.setEntityDescriptorCustomizer(
+				(parameters) -> parameters.getEntityDescriptor().setEntityID("overriddenEntityId"));
+		String metadata = OpenSaml4MetadataResolver.resolve(relyingPartyRegistration);
+		assertThat(metadata).contains("<md:EntityDescriptor").contains("entityID=\"overriddenEntityId\"");
+	}
+
+	@Test
+	public void resolveIterableWhenRelyingPartiesThenMetadataMatches() {
+		RelyingPartyRegistration one = TestRelyingPartyRegistrations.full()
+			.assertionConsumerServiceBinding(Saml2MessageBinding.REDIRECT)
+			.build();
+		RelyingPartyRegistration two = TestRelyingPartyRegistrations.full()
+			.entityId("two")
+			.assertionConsumerServiceBinding(Saml2MessageBinding.REDIRECT)
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		String metadata = OpenSaml4MetadataResolver.resolve(List.of(one, two));
+		assertThat(metadata).contains("<md:EntitiesDescriptor")
+			.contains("<md:EntityDescriptor")
+			.contains("entityID=\"rp-entity-id\"")
+			.contains("entityID=\"two\"")
+			.contains("<md:KeyDescriptor use=\"signing\">")
+			.contains("<md:KeyDescriptor use=\"encryption\">")
+			.contains("<ds:X509Certificate>MIICgTCCAeoCCQCuVzyqFgMSyDANBgkqhkiG9w0BAQsFADCBhDELMAkGA1UEBh")
+			.contains("Binding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect\"")
+			.contains("Location=\"https://rp.example.org/acs\" index=\"1\"")
+			.contains("ResponseLocation=\"https://rp.example.org/logout/saml2/response\"");
+	}
+
+	@Test
+	public void resolveIterableWhenRelyingPartiesAndSignMetadataSetThenMetadataMatches() {
+		RelyingPartyRegistration one = TestRelyingPartyRegistrations.full()
+			.assertionConsumerServiceBinding(Saml2MessageBinding.REDIRECT)
+			.build();
+		RelyingPartyRegistration two = TestRelyingPartyRegistrations.full()
+			.entityId("two")
+			.assertionConsumerServiceBinding(Saml2MessageBinding.REDIRECT)
+			.build();
+		OpenSaml4MetadataResolver OpenSaml4MetadataResolver = new OpenSaml4MetadataResolver();
+		OpenSaml4MetadataResolver.setSignMetadata(true);
+		String metadata = OpenSaml4MetadataResolver.resolve(List.of(one, two));
+		assertThat(metadata).contains("<md:EntitiesDescriptor")
+			.contains("<md:EntityDescriptor")
+			.contains("entityID=\"rp-entity-id\"")
+			.contains("entityID=\"two\"")
+			.contains("<md:KeyDescriptor use=\"signing\">")
+			.contains("<md:KeyDescriptor use=\"encryption\">")
+			.contains("<ds:X509Certificate>MIICgTCCAeoCCQCuVzyqFgMSyDANBgkqhkiG9w0BAQsFADCBhDELMAkGA1UEBh")
+			.contains("Binding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect\"")
+			.contains("Location=\"https://rp.example.org/acs\" index=\"1\"")
+			.contains("ResponseLocation=\"https://rp.example.org/logout/saml2/response\"")
+			.contains("Signature xmlns:ds=\"http://www.w3.org/2000/09/xmldsig#\"")
+			.contains("CanonicalizationMethod Algorithm=\"http://www.w3.org/2001/10/xml-exc-c14n#")
+			.contains("SignatureMethod Algorithm=\"http://www.w3.org/2001/04/xmldsig-more#rsa-sha256")
+			.contains("Reference URI=\"\"")
+			.contains("Transform Algorithm=\"http://www.w3.org/2000/09/xmldsig#enveloped-signature")
+			.contains("Transform Algorithm=\"http://www.w3.org/2001/10/xml-exc-c14n#\"")
+			.contains("DigestMethod Algorithm=\"http://www.w3.org/2001/04/xmlenc#sha256\"")
+			.contains("DigestValue")
+			.contains("SignatureValue");
+	}
+
+}