Detect UserDetailsService bean in remember me

Closes gh-11170

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * 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.
@@ -18,6 +18,8 @@
 
 import java.util.UUID;
 
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.context.ApplicationContext;
 import org.springframework.security.authentication.AuthenticationManager;
 import org.springframework.security.authentication.RememberMeAuthenticationProvider;
 import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
@@ -403,7 +405,7 @@ private AbstractRememberMeServices createPersistentRememberMeServices(H http, St
 	 */
 	private UserDetailsService getUserDetailsService(H http) {
 		if (this.userDetailsService == null) {
-			this.userDetailsService = http.getSharedObject(UserDetailsService.class);
+			this.userDetailsService = getSharedOrBean(http, UserDetailsService.class);
 		}
 		Assert.state(this.userDetailsService != null,
 				() -> "userDetailsService cannot be null. Invoke " + RememberMeConfigurer.class.getSimpleName()
@@ -431,4 +433,25 @@ private String getKey() {
 		return this.key;
 	}
 
+	private <C> C getSharedOrBean(H http, Class<C> type) {
+		C shared = http.getSharedObject(type);
+		if (shared != null) {
+			return shared;
+		}
+		return getBeanOrNull(type);
+	}
+
+	private <T> T getBeanOrNull(Class<T> type) {
+		ApplicationContext context = getBuilder().getSharedObject(ApplicationContext.class);
+		if (context == null) {
+			return null;
+		}
+		try {
+			return context.getBean(type);
+		}
+		catch (NoSuchBeanDefinitionException ex) {
+			return null;
+		}
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * 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.
@@ -42,6 +42,7 @@
 import org.springframework.security.core.userdetails.UserDetailsService;
 import org.springframework.security.provisioning.InMemoryUserDetailsManager;
 import org.springframework.security.test.web.servlet.response.SecurityMockMvcResultMatchers;
+import org.springframework.security.web.SecurityFilterChain;
 import org.springframework.security.web.authentication.RememberMeServices;
 import org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter;
 import org.springframework.security.web.authentication.rememberme.TokenBasedRememberMeServices;
@@ -117,6 +118,20 @@ public void rememberMeWhenInvokedTwiceThenUsesOriginalUserDetailsService() throw
 		verify(DuplicateDoesNotOverrideConfig.userDetailsService).loadUserByUsername("user");
 	}
 
+	@Test
+	public void rememberMeWhenUserDetailsServiceNotConfiguredThenUsesBean() throws Exception {
+		this.spring.register(UserDetailsServiceBeanConfig.class).autowire();
+		MvcResult mvcResult = this.mvc.perform(post("/login").with(csrf()).param("username", "user")
+				.param("password", "password").param("remember-me", "true")).andReturn();
+		Cookie rememberMeCookie = mvcResult.getResponse().getCookie("remember-me");
+		// @formatter:off
+		MockHttpServletRequestBuilder request = get("/abc").cookie(rememberMeCookie);
+		SecurityMockMvcResultMatchers.AuthenticatedMatcher remembermeAuthentication = authenticated()
+				.withAuthentication((auth) -> assertThat(auth).isInstanceOf(RememberMeAuthenticationToken.class));
+		// @formatter:on
+		this.mvc.perform(request).andExpect(remembermeAuthentication);
+	}
+
 	@Test
 	public void loginWhenRememberMeTrueThenRespondsWithRememberMeCookie() throws Exception {
 		this.spring.register(RememberMeConfig.class).autowire();
@@ -370,6 +385,26 @@ public UserDetailsService userDetailsService() {
 
 	}
 
+	@EnableWebSecurity
+	static class UserDetailsServiceBeanConfig {
+
+		@Bean
+		SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
+			// @formatter:off
+			http
+				.formLogin(withDefaults())
+				.rememberMe(withDefaults());
+			// @formatter:on
+			return http.build();
+		}
+
+		@Bean
+		UserDetailsService customUserDetailsService() {
+			return new InMemoryUserDetailsManager(PasswordEncodedUser.user());
+		}
+
+	}
+
 	@EnableWebSecurity
 	static class RememberMeConfig extends WebSecurityConfigurerAdapter {