Add Federation Example

Closes gh-122

servlet/spring-boot/java/saml2/saml-extension-federation/README.adoc

@@ -0,0 +1,78 @@
+= SAML 2.0 Login & Logout Federation Sample using SAML Extension URLs
+
+This guide provides instructions on setting up the new Spring Security SAML 2.0 support using the endpoint URLs from the EOLd Spring Security SAML Extension.
+
+It differs from the `custom-urls` sample in that it is configured to have the registration id be the entity id for each asserting party, an important consideration when federating against hundreds of endpoints.
+This code uses `RelyingPartyRegistrations#collectionFromMetadata` to demonstrate how to copy this relying party's configuration across several arbitrary asserting party configurations returns from a single endpoint.
+
+See the https://github.com/spring-projects/spring-security/wiki/SAML-2.0-Migration-Guide[SAML 2.0 Migration Guide] for more details about the migration.
+
+== Key Changes
+
+=== URL Forwarding Filter
+
+Instead of customizing the default Spring Security configuration, a new `Filter` has been created named `SamlExtensionUrlForwardingFilter`.
+This new filter is responsible to forward from the SAML Extension URLs to the new https://docs.spring.io/spring-security/reference/servlet/saml2/login/overview.html[Spring Security SAML 2.0 support URLs].
+Below is a table with the URLs that the Filter listen to (column 1) and forwards to (column 2).
+
+
+|===
+|SAML Extension URLs |Spring Security SAML 2.0 Support URLs |Description
+
+|`/saml/SSO`
+|`/login/saml2/sso/one`
+|The URL that processes a `<saml2:Response>` from the IdP
+
+|`/saml/login`
+|`/saml2/authenticate/one`
+|The URL that triggers a SAML 2.0 Login
+
+|`/saml/logout`
+|`/logout/saml2/slo`
+|The URL that trigger an SP's initiated SAML 2.0 Logout
+
+|`/saml/SingleLogout`
+|`/logout/saml2/slo`
+|The URL that processes a `<saml2:LogoutRequest>` from the IdP
+
+|`/saml/metadata`
+|`/saml2/service-provider-metadata/one`
+|The URL that generates the SP metadata
+|===
+
+Note that the `SamlExtensionUrlForwardingFilter` has an order of `-102`, this makes it be invoked before the `FilterChainProxy`.
+
+[source,java]
+----
+@Component
+@Order(-102) // To run before FilterChainProxy
+public class SamlExtensionUrlForwardingFilter extends OncePerRequestFilter {
+	// ...
+}
+----
+
+=== application.yml
+
+[source%linenums,yml]
+----
+spring:
+  security:
+    filter:
+      dispatcher-types: async, error, request, forward <1>
+    saml2:
+      relyingparty:
+        registration:
+          one:
+            singlelogout:
+              binding: POST
+              url: "{baseUrl}/saml/logout" <2>
+              responseUrl: "{baseUrl}/saml/SingleLogout" <3>
+            acs:
+              location: "{baseUrl}/saml/SSO" <4>
+            assertingparty.metadata-uri: https://dev-05937739.okta.com/app/exk598vc9bHhwoTXM5d7/sso/saml/metadata
+----
+
+==== `RelyingPartyRegistration` properties
+
+The `RelyingPartyRegistration` properties should also be customized to match the values that were used by the SAML Extension (see <2>, <3> and <4> above).
+

servlet/spring-boot/java/saml2/saml-extension-federation/build.gradle

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+plugins {
+	id 'org.springframework.boot' version '3.0.0-SNAPSHOT'
+	id 'io.spring.dependency-management' version '1.0.11.RELEASE'
+	id "nebula.integtest" version "8.2.0"
+	id 'java'
+}
+
+repositories {
+	mavenCentral()
+	maven { url "https://repo.spring.io/milestone" }
+	maven { url "https://repo.spring.io/snapshot" }
+	maven { url "https://build.shibboleth.net/nexus/content/repositories/releases/" }
+}
+
+dependencies {
+	constraints {
+		implementation "org.opensaml:opensaml-core:4.1.1"
+		implementation "org.opensaml:opensaml-saml-api:4.1.1"
+		implementation "org.opensaml:opensaml-saml-impl:4.1.1"
+	}
+	implementation 'org.springframework.boot:spring-boot-starter-security'
+	implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation 'org.springframework.security:spring-security-saml2-service-provider'
+	implementation 'org.thymeleaf.extras:thymeleaf-extras-springsecurity6'
+
+	testImplementation 'net.sourceforge.htmlunit:htmlunit'
+	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+	testImplementation 'org.springframework.security:spring-security-test'
+}
+
+tasks.withType(Test).configureEach {
+	useJUnitPlatform()
+	outputs.upToDateWhen { false }
+}

servlet/spring-boot/java/saml2/saml-extension-federation/gradle.properties

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+version=6.0.0-SNAPSHOT
+spring-security.version=6.0.0-SNAPSHOT

servlet/spring-boot/java/saml2/saml-extension-federation/gradle/wrapper/gradle-wrapper.properties

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+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

servlet/spring-boot/java/saml2/saml-extension-federation/gradlew

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+#!/usr/bin/env sh
+
+#
+# Copyright 2015 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.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

servlet/spring-boot/java/saml2/saml-extension-federation/gradlew.bat

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+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

servlet/spring-boot/java/saml2/saml-extension-federation/src/integTest/java/example/SamlExtensionFederationApplicationITests.java

@@ -0,0 +1,114 @@
+/*
+ * Copyright 2002-2021 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 example;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.gargoylesoftware.htmlunit.ElementNotFoundException;
+import com.gargoylesoftware.htmlunit.WebClient;
+import com.gargoylesoftware.htmlunit.html.HtmlElement;
+import com.gargoylesoftware.htmlunit.html.HtmlForm;
+import com.gargoylesoftware.htmlunit.html.HtmlInput;
+import com.gargoylesoftware.htmlunit.html.HtmlPage;
+import com.gargoylesoftware.htmlunit.html.HtmlPasswordInput;
+import com.gargoylesoftware.htmlunit.html.HtmlSubmitInput;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.forwardedUrl;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@Disabled
+@SpringBootTest
+@AutoConfigureMockMvc
+public class SamlExtensionFederationApplicationITests {
+
+	@Autowired
+	MockMvc mvc;
+
+	@Autowired
+	WebClient webClient;
+
+	@BeforeEach
+	void setup() {
+		this.webClient.getCookieManager().clearCookies();
+	}
+
+	@Test
+	void authenticationAttemptWhenValidThenShowsUserEmailAddress() throws Exception {
+		performLogin();
+		HtmlPage home = (HtmlPage) this.webClient.getCurrentWindow().getEnclosedPage();
+		assertThat(home.asNormalizedText()).contains("You're email address is testuser2@spring.security.saml");
+	}
+
+	@Test
+	void logoutWhenRelyingPartyInitiatedLogoutThenLoginPageWithLogoutParam() throws Exception {
+		performLogin();
+		HtmlPage home = (HtmlPage) this.webClient.getCurrentWindow().getEnclosedPage();
+		HtmlElement rpLogoutButton = home.getHtmlElementById("rp_logout_button");
+		HtmlPage loginPage = rpLogoutButton.click();
+		this.webClient.waitForBackgroundJavaScript(10000);
+		List<String> urls = new ArrayList<>();
+		urls.add(loginPage.getUrl().getFile());
+		urls.add(((HtmlPage) this.webClient.getCurrentWindow().getEnclosedPage()).getUrl().getFile());
+		assertThat(urls).contains("/login?logout");
+	}
+
+	@Test
+	void metadataWhenGetThenForwardToUrl() throws Exception {
+		this.mvc.perform(get("/saml/metadata")).andExpect(status().isOk())
+				.andExpect(forwardedUrl("/saml2/service-provider-metadata/one"));
+	}
+
+	private void performLogin() throws Exception {
+		HtmlPage login = this.webClient.getPage("/");
+		login.getAnchors().get(0).click();
+		this.webClient.waitForBackgroundJavaScript(10000);
+		HtmlForm form = findForm(login);
+		HtmlInput username = form.getInputByName("username");
+		HtmlPasswordInput password = form.getInputByName("password");
+		HtmlSubmitInput submit = login.getHtmlElementById("okta-signin-submit");
+		username.type("testuser2@spring.security.saml");
+		password.type("12345678");
+		submit.click();
+		this.webClient.waitForBackgroundJavaScript(10000);
+	}
+
+	private HtmlForm findForm(HtmlPage login) {
+		for (HtmlForm form : login.getForms()) {
+			try {
+				if (form.getId().equals("form19")) {
+					return form;
+				}
+			}
+			catch (ElementNotFoundException ex) {
+				// Continue
+			}
+		}
+		throw new IllegalStateException("Could not resolve login form");
+	}
+
+}

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/java/example/EntityIdRelyingPartyRegistrationResolver.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2023 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 example;
+
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+import jakarta.servlet.http.HttpServletRequest;
+import net.shibboleth.utilities.java.support.xml.ParserPool;
+import org.opensaml.core.config.ConfigurationService;
+import org.opensaml.core.xml.config.XMLObjectProviderRegistry;
+import org.opensaml.saml.saml2.core.Response;
+import org.opensaml.saml.saml2.core.impl.ResponseUnmarshaller;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+import org.springframework.security.saml2.core.OpenSamlInitializationService;
+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.provider.service.authentication.Saml2AuthenticationException;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistrationRepository;
+import org.springframework.security.saml2.provider.service.web.DefaultRelyingPartyRegistrationResolver;
+import org.springframework.security.saml2.provider.service.web.RelyingPartyRegistrationResolver;
+
+public class EntityIdRelyingPartyRegistrationResolver implements RelyingPartyRegistrationResolver {
+	static {
+		OpenSamlInitializationService.initialize();
+	}
+
+	private final ResponseUnmarshaller responseUnmarshaller;
+	private final ParserPool parserPool;
+
+	private final RelyingPartyRegistrationResolver delegate;
+
+	public EntityIdRelyingPartyRegistrationResolver(RelyingPartyRegistrationRepository registrations) {
+		XMLObjectProviderRegistry registry = ConfigurationService.get(XMLObjectProviderRegistry.class);
+		this.responseUnmarshaller = (ResponseUnmarshaller) registry.getUnmarshallerFactory()
+				.getUnmarshaller(Response.DEFAULT_ELEMENT_NAME);
+		this.parserPool = registry.getParserPool();
+		this.delegate = new DefaultRelyingPartyRegistrationResolver(registrations);
+	}
+
+	@Override
+	public RelyingPartyRegistration resolve(HttpServletRequest request, String relyingPartyRegistrationId) {
+		if (relyingPartyRegistrationId != null) {
+			return this.delegate.resolve(request, relyingPartyRegistrationId);
+		}
+		return this.delegate.resolve(request, resolveRegistrationId(request));
+	}
+
+	private String resolveRegistrationId(HttpServletRequest request) {
+		String saml2Response = request.getParameter(Saml2ParameterNames.SAML_RESPONSE);
+		if (saml2Response == null) {
+			return null;
+		}
+		byte[] decoded = Base64.getMimeDecoder().decode(saml2Response);
+		String serialized = new String(decoded, StandardCharsets.UTF_8);
+		return parseResponse(serialized).getIssuer().getValue();
+	}
+
+	private Response parseResponse(String serialized) {
+		try {
+			Document document = this.parserPool
+					.parse(new ByteArrayInputStream(serialized.getBytes(StandardCharsets.UTF_8)));
+			Element element = document.getDocumentElement();
+			return (Response) this.responseUnmarshaller.unmarshall(element);
+		}
+		catch (Exception ex) {
+			Saml2Error error = new Saml2Error(Saml2ErrorCodes.MALFORMED_RESPONSE_DATA, ex.getMessage());
+			throw new Saml2AuthenticationException(error, ex.getMessage());
+		}
+	}
+}

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/java/example/IndexController.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2020 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 example;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
+import org.springframework.security.saml2.provider.service.authentication.Saml2AuthenticatedPrincipal;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+
+@Controller
+public class IndexController {
+
+	private final Iterable<RelyingPartyRegistration> registrations;
+
+	@Autowired
+	public IndexController(Iterable<RelyingPartyRegistration> registrations) {
+		this.registrations = registrations;
+	}
+
+	@GetMapping("/")
+	public String index(Model model, @AuthenticationPrincipal Saml2AuthenticatedPrincipal principal) {
+		String emailAddress = principal.getFirstAttribute("email");
+		model.addAttribute("emailAddress", emailAddress);
+		model.addAttribute("userAttributes", principal.getAttributes());
+		return "index";
+	}
+
+	@GetMapping("/login")
+	public String login(Model model) {
+		Collection<String> urls = new ArrayList<>();
+		for (RelyingPartyRegistration registration : this.registrations) {
+			urls.add("/saml/login?id=" + registration.getRegistrationId());
+		}
+		model.addAttribute("urls", urls);
+		return "login";
+	}
+
+}

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/java/example/SamlExtensionFederationApplication.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2002-2022 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 example;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SamlExtensionFederationApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SamlExtensionFederationApplication.class, args);
+	}
+
+}

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/java/example/SamlExtensionUrlForwardingFilter.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2002-2022 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 example;
+
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import jakarta.servlet.FilterChain;
+import jakarta.servlet.RequestDispatcher;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import org.springframework.core.annotation.Order;
+import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
+import org.springframework.security.web.util.matcher.OrRequestMatcher;
+import org.springframework.security.web.util.matcher.RequestMatcher;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+
+@Component
+@Order(-102) // To run before FilterChainProxy
+public class SamlExtensionUrlForwardingFilter extends OncePerRequestFilter {
+
+	// @formatter:off
+	private static final Map<String, String> urlMapping = Map.of("/saml/SSO", "/login/saml2/sso/one",
+			"/saml/login", "/saml2/authenticate/one",
+			"/saml/logout", "/logout/saml2/slo",
+			"/saml/SingleLogout", "/logout/saml2/slo",
+			"/saml/metadata", "/saml2/service-provider-metadata/one");
+	// @formatter:on
+
+	private final RequestMatcher matcher = createRequestMatcher();
+
+	private RequestMatcher createRequestMatcher() {
+		Set<String> urls = urlMapping.keySet();
+		List<RequestMatcher> matchers = new LinkedList<>();
+		urls.forEach((url) -> matchers.add(new AntPathRequestMatcher(url)));
+		return new OrRequestMatcher(matchers);
+	}
+
+	@Override
+	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
+			throws ServletException, IOException {
+		boolean match = this.matcher.matches(request);
+		if (!match) {
+			filterChain.doFilter(request, response);
+			return;
+		}
+		String forwardUrl = urlMapping.get(request.getRequestURI());
+		RequestDispatcher dispatcher = request.getRequestDispatcher(forwardUrl);
+		dispatcher.forward(request, response);
+	}
+
+}

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/java/example/SecurityConfiguration.java

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2002-2022 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 example;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.KeyStore;
+import java.security.cert.CertificateException;
+import java.security.cert.CertificateFactory;
+import java.security.cert.X509Certificate;
+import java.security.interfaces.RSAPrivateKey;
+import java.util.stream.Collectors;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyProperties;
+import org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyProperties.Registration;
+import org.springframework.boot.web.servlet.FilterRegistrationBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.Order;
+import org.springframework.security.config.Customizer;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.saml2.core.Saml2X509Credential;
+import org.springframework.security.saml2.provider.service.metadata.OpenSamlMetadataResolver;
+import org.springframework.security.saml2.provider.service.registration.InMemoryRelyingPartyRegistrationRepository;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistration;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistrationRepository;
+import org.springframework.security.saml2.provider.service.registration.RelyingPartyRegistrations;
+import org.springframework.security.saml2.provider.service.web.DefaultRelyingPartyRegistrationResolver;
+import org.springframework.security.saml2.provider.service.web.Saml2AuthenticationTokenConverter;
+import org.springframework.security.saml2.provider.service.web.Saml2MetadataFilter;
+import org.springframework.security.saml2.provider.service.web.authentication.OpenSaml4AuthenticationRequestResolver;
+import org.springframework.security.saml2.provider.service.web.authentication.Saml2AuthenticationRequestResolver;
+import org.springframework.security.web.SecurityFilterChain;
+
+@Configuration
+@EnableWebSecurity
+public class SecurityConfiguration {
+
+	@Bean
+	SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
+		// @formatter:off
+		http
+			.authorizeHttpRequests((authorize) -> authorize
+				.requestMatchers("/login", "/error").permitAll()
+				.anyRequest().authenticated()
+			)
+			.saml2Login((saml2) -> saml2.loginPage("/login"))
+			.saml2Logout(Customizer.withDefaults());
+		// @formatter:on
+		return http.build();
+	}
+
+
+	@Bean
+	Saml2AuthenticationTokenConverter usingEntityId(RelyingPartyRegistrationRepository repository) {
+		var registrations = new EntityIdRelyingPartyRegistrationResolver(repository);
+		return new Saml2AuthenticationTokenConverter(registrations);
+	}
+
+	@Bean
+	Saml2AuthenticationRequestResolver usingQueryParameter(RelyingPartyRegistrationRepository repository) {
+		var registrations = new DefaultRelyingPartyRegistrationResolver(repository);
+		return new OpenSaml4AuthenticationRequestResolver((request, id) ->
+			registrations.resolve(request, request.getParameter("id")));
+	}
+
+	@Bean
+	@Order(-101)
+	FilterRegistrationBean<Saml2MetadataFilter> metadata(Iterable<RelyingPartyRegistration> repository) {
+		var registrations = new DefaultRelyingPartyRegistrationResolver((id) -> repository.iterator().next());
+		var filter = new Saml2MetadataFilter(registrations, new OpenSamlMetadataResolver());
+		return new FilterRegistrationBean<>(filter);
+	}
+
+	@Bean
+	InMemoryRelyingPartyRegistrationRepository repository(Saml2RelyingPartyProperties properties,
+			 @Value("classpath:credentials/rp-private.key") RSAPrivateKey key,
+			 @Value("classpath:credentials/rp-certificate.crt") File cert) {
+		Saml2X509Credential signing = Saml2X509Credential.signing(key, x509Certificate(cert));
+		Registration registration = properties.getRegistration().get("one");
+		return new InMemoryRelyingPartyRegistrationRepository(RelyingPartyRegistrations
+				.collectionFromMetadataLocation(registration.getAssertingparty().getMetadataUri())
+				.stream().map((builder) -> builder
+						.entityId(registration.getEntityId())
+						.assertionConsumerServiceLocation(registration.getAcs().getLocation())
+						.singleLogoutServiceLocation(registration.getSinglelogout().getUrl())
+						.singleLogoutServiceResponseLocation(registration.getSinglelogout().getResponseUrl())
+						.signingX509Credentials(credentials -> credentials.add(signing))
+						.build()
+				).collect(Collectors.toList()));
+	}
+
+	X509Certificate x509Certificate(File location) {
+		try (InputStream source = new FileInputStream(location)) {
+			return (X509Certificate) CertificateFactory.getInstance("X.509").generateCertificate(source);
+		} catch (CertificateException | IOException ex) {
+			throw new IllegalArgumentException(ex);
+		}
+	}
+}

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/resources/application.yml

@@ -0,0 +1,19 @@
+logging.level:
+  org.springframework.security: TRACE
+
+spring:
+  security:
+    filter:
+      dispatcher-types: async, error, request, forward
+    saml2:
+      relyingparty:
+        registration:
+          one:
+            entity-id: "{baseUrl}/saml2/service-provider-metadata/one"
+            singlelogout:
+              binding: POST
+              url: "{baseUrl}/saml/logout"
+              responseUrl: "{baseUrl}/saml/SingleLogout"
+            acs:
+              location: "{baseUrl}/saml/SSO"
+            assertingparty.metadata-uri: https://dev-05937739.okta.com/app/exk598vc9bHhwoTXM5d7/sso/saml/metadata

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/resources/credentials/idp-certificate.crt

@@ -0,0 +1,24 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/resources/credentials/rp-certificate.crt

@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/resources/credentials/rp-private.key

@@ -0,0 +1,16 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/resources/templates/index.html

@@ -0,0 +1,55 @@
+<!--
+  ~ Copyright 2002-2021 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.
+  -->
+
+<!doctype html>
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="https://www.thymeleaf.org" xmlns:sec="https://www.thymeleaf.org/thymeleaf-extras-springsecurity5">
+<head>
+    <title>Spring Security - SAML 2.0 Login & Logout</title>
+    <meta charset="utf-8" />
+    <style>
+        span, dt {
+            font-weight: bold;
+        }
+    </style>
+    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
+</head>
+<body>
+<div class="container">
+    <ul class="nav">
+        <li class="nav-item">
+            <form th:action="@{/logout}" method="post">
+                <button class="btn btn-primary" id="rp_logout_button" type="submit">
+                    RP-initiated Logout
+                </button>
+            </form>
+        </li>
+    </ul>
+    </div>
+    <main role="main" class="container">
+        <h1 class="mt-5">SAML 2.0 Login & Single Logout with Spring Security</h1>
+        <p class="lead">You are successfully logged in as <span sec:authentication="name"></span></p>
+        <p class="lead">You're email address is <span th:text="${emailAddress}"></span></p>
+        <h2 class="mt-2">All Your Attributes</h2>
+        <dl th:each="userAttribute : ${userAttributes}">
+            <dt th:text="${userAttribute.key}"></dt>
+            <dd th:text="${userAttribute.value}"></dd>
+        </dl>
+
+        <h6>Visit the <a href="https://docs.spring.io/spring-security/site/docs/current/reference/html5/#servlet-saml2" target="_blank">SAML 2.0 Login & Logout</a> documentation for more details.</h6>
+    </main>
+</div>
+</body>
+</html>

servlet/spring-boot/java/saml2/saml-extension-federation/src/main/resources/templates/login.html

@@ -0,0 +1,38 @@
+<!--
+  ~ Copyright 2002-2021 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.
+  -->
+
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <title>Please sign in</title>
+    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" rel="stylesheet"
+          integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
+    <link href="https://getbootstrap.com/docs/4.0/examples/signin/signin.css" rel="stylesheet" crossorigin="anonymous">
+</head>
+<body data-new-gr-c-s-check-loaded="8.904.0" data-gr-ext-installed="">
+<div class="container">
+    <h2 class="form-signin-heading">Login with SAML 2.0</h2>
+    <table class="table table-striped">
+        <tbody>
+        <tr th:each="url : ${urls}">
+            <td><a th:href="${url}"><span th:text="${url}"></span></a></td>
+        </tr>
+        </tbody>
+    </table>
+</div>
+</body>
+</html>

settings.gradle

@@ -65,6 +65,7 @@ include ":servlet:spring-boot:java:saml2:login"
 include ":servlet:spring-boot:java:saml2:login-single-tenant"
 include ":servlet:spring-boot:java:saml2:refreshable-metadata"
 include ":servlet:spring-boot:java:saml2:custom-urls"
+include ":servlet:spring-boot:java:saml2:saml-extension-federation"
 include ":servlet:spring-boot:kotlin:hello-security"
 include ":servlet:xml:java:helloworld"
 include ":servlet:xml:java:preauth"