Add EncryptedAttribute support

Closes gh-9131

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationProvider.java

@@ -69,6 +69,7 @@ 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.NameID;
 import org.opensaml.saml.saml2.core.OneTimeUse;
 import org.opensaml.saml.saml2.core.Response;
@@ -647,6 +648,17 @@ public final class OpenSamlAuthenticationProvider implements AuthenticationProvi
 		return (assertionToken) -> {
 			Decrypter decrypter = this.decrypterConverter.convert(assertionToken.getToken());
 			Assertion assertion = assertionToken.getAssertion();
+			for (AttributeStatement statement : assertion.getAttributeStatements()) {
+				for (EncryptedAttribute encryptedAttribute : statement.getEncryptedAttributes()) {
+					try {
+						Attribute attribute = decrypter.decrypt(encryptedAttribute);
+						statement.getAttributes().add(attribute);
+					}
+					catch (Exception ex) {
+						throw createAuthenticationException(Saml2ErrorCodes.DECRYPTION_ERROR, ex.getMessage(), ex);
+					}
+				}
+			}
 			if (assertion.getSubject() == null) {
 				return;
 			}

saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationProviderTests.java

@@ -43,6 +43,7 @@ import org.opensaml.saml.saml2.assertion.SAML2AssertionValidationParameters;
 import org.opensaml.saml.saml2.core.Assertion;
 import org.opensaml.saml.saml2.core.AttributeStatement;
 import org.opensaml.saml.saml2.core.EncryptedAssertion;
+import org.opensaml.saml.saml2.core.EncryptedAttribute;
 import org.opensaml.saml.saml2.core.EncryptedID;
 import org.opensaml.saml.saml2.core.NameID;
 import org.opensaml.saml.saml2.core.OneTimeUse;
@@ -298,6 +299,25 @@ public class OpenSamlAuthenticationProviderTests {
 		this.provider.authenticate(token);
 	}
 
+	@Test
+	public void authenticateWhenEncryptedAttributeThenDecrypts() {
+		Response response = TestOpenSamlObjects.response();
+		Assertion assertion = TestOpenSamlObjects.assertion();
+		EncryptedAttribute attribute = TestOpenSamlObjects.encrypted("name", "value",
+				TestSaml2X509Credentials.assertingPartyEncryptingCredential());
+		AttributeStatement statement = build(AttributeStatement.DEFAULT_ELEMENT_NAME);
+		statement.getEncryptedAttributes().add(attribute);
+		assertion.getAttributeStatements().add(statement);
+		response.getAssertions().add(assertion);
+		TestOpenSamlObjects.signed(response, TestSaml2X509Credentials.assertingPartySigningCredential(),
+				RELYING_PARTY_ENTITY_ID);
+		Saml2AuthenticationToken token = token(response, TestSaml2X509Credentials.relyingPartyVerifyingCredential(),
+				TestSaml2X509Credentials.relyingPartyDecryptingCredential());
+		Saml2Authentication authentication = (Saml2Authentication) this.provider.authenticate(token);
+		Saml2AuthenticatedPrincipal principal = (Saml2AuthenticatedPrincipal) authentication.getPrincipal();
+		assertThat(principal.getAttribute("name")).containsExactly("value");
+	}
+
 	@Test
 	public void authenticateWhenDecryptionKeysAreMissingThenThrowAuthenticationException() throws Exception {
 		Response response = TestOpenSamlObjects.response();

saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/authentication/TestOpenSamlObjects.java

@@ -59,6 +59,7 @@ import org.opensaml.saml.saml2.core.AttributeValue;
 import org.opensaml.saml.saml2.core.AuthnRequest;
 import org.opensaml.saml.saml2.core.Conditions;
 import org.opensaml.saml.saml2.core.EncryptedAssertion;
+import org.opensaml.saml.saml2.core.EncryptedAttribute;
 import org.opensaml.saml.saml2.core.EncryptedID;
 import org.opensaml.saml.saml2.core.Issuer;
 import org.opensaml.saml.saml2.core.NameID;
@@ -301,6 +302,18 @@ public final class TestOpenSamlObjects {
 		}
 	}
 
+	static EncryptedAttribute encrypted(String name, String value, Saml2X509Credential credential) {
+		Attribute attribute = attribute(name, value);
+		X509Certificate certificate = credential.getCertificate();
+		Encrypter encrypter = getEncrypter(certificate);
+		try {
+			return encrypter.encrypt(attribute);
+		}
+		catch (EncryptionException ex) {
+			throw new Saml2Exception("Unable to encrypt nameID.", ex);
+		}
+	}
+
 	private static Encrypter getEncrypter(X509Certificate certificate) {
 		String dataAlgorithm = XMLCipherParameters.AES_256;
 		String keyAlgorithm = XMLCipherParameters.RSA_1_5;
@@ -318,6 +331,15 @@ public final class TestOpenSamlObjects {
 		return encrypter;
 	}
 
+	static Attribute attribute(String name, String value) {
+		Attribute attribute = build(Attribute.DEFAULT_ELEMENT_NAME);
+		attribute.setName(name);
+		XSString xsValue = new XSStringBuilder().buildObject(AttributeValue.DEFAULT_ELEMENT_NAME, XSString.TYPE_NAME);
+		xsValue.setValue(value);
+		attribute.getAttributeValues().add(xsValue);
+		return attribute;
+	}
+
 	static List<AttributeStatement> attributeStatements() {
 		List<AttributeStatement> attributeStatements = new ArrayList<>();
 		AttributeStatementBuilder attributeStatementBuilder = new AttributeStatementBuilder();