Deprecate Saml2AuthenticationRequestFilter Constructor

Removing the default usage of OpenSamlAuthenticationRequestFactory.
Otherwise, the Open SAML dependency is required, even when
Saml2AuthenticationRequestFactory is implemented without it.

Fixes gh-8359

config/src/main/java/org/springframework/security/config/annotation/web/configurers/saml2/Saml2LoginConfigurer.java

@@ -16,6 +16,10 @@
 
 package org.springframework.security.config.annotation.web.configurers.saml2;
 
+import java.util.LinkedHashMap;
+import java.util.Map;
+import javax.servlet.Filter;
+
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.security.authentication.AuthenticationManager;
@@ -37,10 +41,6 @@ import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
 import org.springframework.security.web.util.matcher.RequestMatcher;
 import org.springframework.util.Assert;
 
-import java.util.LinkedHashMap;
-import java.util.Map;
-import javax.servlet.Filter;
-
 import static org.springframework.util.StringUtils.hasText;
 
 /**
@@ -323,10 +323,9 @@ public final class Saml2LoginConfigurer<B extends HttpSecurityBuilder<B>> extend
 		private Filter build(B http) {
 			Saml2AuthenticationRequestFactory authenticationRequestResolver = getResolver(http);
 
-			Saml2WebSsoAuthenticationRequestFilter authenticationRequestFilter =
-					new Saml2WebSsoAuthenticationRequestFilter(Saml2LoginConfigurer.this.relyingPartyRegistrationRepository);
-			authenticationRequestFilter.setAuthenticationRequestFactory(authenticationRequestResolver);
-			return authenticationRequestFilter;
+			return new Saml2WebSsoAuthenticationRequestFilter(
+							Saml2LoginConfigurer.this.relyingPartyRegistrationRepository,
+							authenticationRequestResolver);
 		}
 
 		private Saml2AuthenticationRequestFactory getResolver(B http) {

saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/servlet/filter/Saml2WebSsoAuthenticationRequestFilter.java

@@ -24,7 +24,6 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.springframework.http.MediaType;
-import org.springframework.security.saml2.provider.service.authentication.OpenSamlAuthenticationRequestFactory;
 import org.springframework.security.saml2.provider.service.authentication.Saml2AuthenticationRequestContext;
 import org.springframework.security.saml2.provider.service.authentication.Saml2AuthenticationRequestFactory;
 import org.springframework.security.saml2.provider.service.authentication.Saml2PostAuthenticationRequest;
@@ -71,24 +70,43 @@ import static org.springframework.util.StringUtils.hasText;
 public class Saml2WebSsoAuthenticationRequestFilter extends OncePerRequestFilter {
 
 	private final RelyingPartyRegistrationRepository relyingPartyRegistrationRepository;
+	private Saml2AuthenticationRequestFactory authenticationRequestFactory;
+
 	private RequestMatcher redirectMatcher = new AntPathRequestMatcher("/saml2/authenticate/{registrationId}");
-	private Saml2AuthenticationRequestFactory authenticationRequestFactory = new OpenSamlAuthenticationRequestFactory();
 
 	/**
 	 * Construct a {@link Saml2WebSsoAuthenticationRequestFilter} with the provided parameters
 	 *
 	 * @param relyingPartyRegistrationRepository a repository for relying party configurations
+	 * @deprecated use the constructor that takes a {@link Saml2AuthenticationRequestFactory}
 	 */
+	@Deprecated
 	public Saml2WebSsoAuthenticationRequestFilter(RelyingPartyRegistrationRepository relyingPartyRegistrationRepository) {
+		this(relyingPartyRegistrationRepository,
+				new org.springframework.security.saml2.provider.service.authentication.OpenSamlAuthenticationRequestFactory());
+	}
+
+	/**
+	 * Construct a {@link Saml2WebSsoAuthenticationRequestFilter} with the provided parameters
+	 *
+	 * @param relyingPartyRegistrationRepository a repository for relying party configurations
+	 * @since 5.4
+	 */
+	public Saml2WebSsoAuthenticationRequestFilter(RelyingPartyRegistrationRepository relyingPartyRegistrationRepository,
+			Saml2AuthenticationRequestFactory authenticationRequestFactory) {
 		Assert.notNull(relyingPartyRegistrationRepository, "relyingPartyRegistrationRepository cannot be null");
+		Assert.notNull(authenticationRequestFactory, "authenticationRequestFactory cannot be null");
 		this.relyingPartyRegistrationRepository = relyingPartyRegistrationRepository;
+		this.authenticationRequestFactory = authenticationRequestFactory;
 	}
 
 	/**
 	 * Use the given {@link Saml2AuthenticationRequestFactory} for formulating the SAML 2.0 AuthnRequest
 	 *
 	 * @param authenticationRequestFactory the {@link Saml2AuthenticationRequestFactory} to use
+	 * @deprecated use the constructor instead
 	 */
+	@Deprecated
 	public void setAuthenticationRequestFactory(Saml2AuthenticationRequestFactory authenticationRequestFactory) {
 		Assert.notNull(authenticationRequestFactory, "authenticationRequestFactory cannot be null");
 		this.authenticationRequestFactory = authenticationRequestFactory;

saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/servlet/filter/Saml2WebSsoAuthenticationRequestFilterTests.java

@@ -179,6 +179,29 @@ public class Saml2WebSsoAuthenticationRequestFilterTests {
 		verify(this.factory).createPostAuthenticationRequest(any());
 	}
 
+	@Test
+	public void doFilterWhenCustomAuthenticationRequestFactoryThenUses() throws Exception {
+		RelyingPartyRegistration relyingParty = this.rpBuilder
+				.providerDetails(c -> c.binding(POST))
+				.build();
+		Saml2PostAuthenticationRequest authenticationRequest = mock(Saml2PostAuthenticationRequest.class);
+		when(authenticationRequest.getAuthenticationRequestUri()).thenReturn("uri");
+		when(authenticationRequest.getRelayState()).thenReturn("relay");
+		when(authenticationRequest.getSamlRequest()).thenReturn("saml");
+		when(this.repository.findByRegistrationId("registration-id")).thenReturn(relyingParty);
+		when(this.factory.createPostAuthenticationRequest(any()))
+				.thenReturn(authenticationRequest);
+
+		Saml2WebSsoAuthenticationRequestFilter filter = new Saml2WebSsoAuthenticationRequestFilter
+				(this.repository, this.factory);
+		filter.doFilterInternal(this.request, this.response, this.filterChain);
+		assertThat(this.response.getContentAsString())
+				.contains("<form action=\"uri\" method=\"post\">")
+				.contains("<input type=\"hidden\" name=\"SAMLRequest\" value=\"saml\"")
+				.contains("<input type=\"hidden\" name=\"RelayState\" value=\"relay\"");
+		verify(this.factory).createPostAuthenticationRequest(any());
+	}
+
 	@Test
 	public void setRequestMatcherWhenNullThenException() {
 		Saml2WebSsoAuthenticationRequestFilter filter = new Saml2WebSsoAuthenticationRequestFilter