Add CsrfFilter.csrfRequestAttributeName

Previously the CsrfToken was set on the request attribute with the name
equal to CsrfToken.getParameterName(). This didn't really make a lot of
sense because the CsrfToken.getParameterName() is intended to be used as
the HTTP parameter that the CSRF token was provided. What's more is it
meant that the CsrfToken needed to be read for every request to place it
as an HttpServletRequestAttribute. This causes unnecessary HttpSession
access which can decrease performance for applications.

This commit allows setting CsrfFilter.csrfReqeustAttributeName to
remove the dual purposing of CsrfToken.parameterName and to allow deferal
of reading the CsrfToken to prevent unnecessary HttpSession access.

Issue gh-11699

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

@@ -89,6 +89,8 @@ public final class CsrfConfigurer<H extends HttpSecurityBuilder<H>>
 
 	private SessionAuthenticationStrategy sessionAuthenticationStrategy;
 
+	private String csrfRequestAttributeName;
+
 	private final ApplicationContext context;
 
 	/**
@@ -124,6 +126,16 @@ public final class CsrfConfigurer<H extends HttpSecurityBuilder<H>>
 		return this;
 	}
 
+	/**
+	 * Sets the {@link CsrfFilter#setCsrfRequestAttributeName(String)}
+	 * @param csrfRequestAttributeName the attribute name to set the CsrfToken on.
+	 * @return the {@link CsrfConfigurer} for further customizations.
+	 */
+	public CsrfConfigurer<H> csrfRequestAttributeName(String csrfRequestAttributeName) {
+		this.csrfRequestAttributeName = csrfRequestAttributeName;
+		return this;
+	}
+
 	/**
 	 * <p>
 	 * Allows specifying {@link HttpServletRequest} that should not use CSRF Protection
@@ -202,6 +214,9 @@ public final class CsrfConfigurer<H extends HttpSecurityBuilder<H>>
 	@Override
 	public void configure(H http) {
 		CsrfFilter filter = new CsrfFilter(this.csrfTokenRepository);
+		if (this.csrfRequestAttributeName != null) {
+			filter.setCsrfRequestAttributeName(this.csrfRequestAttributeName);
+		}
 		RequestMatcher requireCsrfProtectionMatcher = getRequireCsrfProtectionMatcher();
 		if (requireCsrfProtectionMatcher != null) {
 			filter.setRequireCsrfProtectionMatcher(requireCsrfProtectionMatcher);

config/src/main/java/org/springframework/security/config/http/CsrfBeanDefinitionParser.java

@@ -67,10 +67,14 @@ public class CsrfBeanDefinitionParser implements BeanDefinitionParser {
 
 	private static final String DISPATCHER_SERVLET_CLASS_NAME = "org.springframework.web.servlet.DispatcherServlet";
 
+	private static final String ATT_REQUEST_ATTRIBUTE_NAME = "request-attribute-name";
+
 	private static final String ATT_MATCHER = "request-matcher-ref";
 
 	private static final String ATT_REPOSITORY = "token-repository-ref";
 
+	private String requestAttributeName;
+
 	private String csrfRepositoryRef;
 
 	private BeanDefinition csrfFilter;
@@ -94,6 +98,7 @@ public class CsrfBeanDefinitionParser implements BeanDefinitionParser {
 		}
 		if (element != null) {
 			this.csrfRepositoryRef = element.getAttribute(ATT_REPOSITORY);
+			this.requestAttributeName = element.getAttribute(ATT_REQUEST_ATTRIBUTE_NAME);
 			this.requestMatcherRef = element.getAttribute(ATT_MATCHER);
 		}
 		if (!StringUtils.hasText(this.csrfRepositoryRef)) {
@@ -110,6 +115,9 @@ public class CsrfBeanDefinitionParser implements BeanDefinitionParser {
 		if (StringUtils.hasText(this.requestMatcherRef)) {
 			builder.addPropertyReference("requireCsrfProtectionMatcher", this.requestMatcherRef);
 		}
+		if (StringUtils.hasText(this.requestAttributeName)) {
+			builder.addPropertyValue("csrfRequestAttributeName", this.requestAttributeName);
+		}
 		this.csrfFilter = builder.getBeanDefinition();
 		return this.csrfFilter;
 	}

config/src/main/resources/org/springframework/security/config/spring-security-5.8.rnc

@@ -1136,6 +1136,9 @@ csrf =
 csrf-options.attlist &=
 	## Specifies if csrf protection should be disabled. Default false (i.e. CSRF protection is enabled).
 	attribute disabled {xsd:boolean}?
+csrf-options.attlist &=
+	## The request attribute name the CsrfToken is set on. Default is to set to CsrfToken.parameterName
+	attribute request-attribute-name { xsd:token }?
 csrf-options.attlist &=
 	## The RequestMatcher instance to be used to determine if CSRF should be applied. Default is any HTTP method except "GET", "TRACE", "HEAD", "OPTIONS"
 	attribute request-matcher-ref { xsd:token }?

config/src/main/resources/org/springframework/security/config/spring-security-5.8.xsd

@@ -3217,6 +3217,13 @@
                 </xs:documentation>
          </xs:annotation>
       </xs:attribute>
+      <xs:attribute name="request-attribute-name" type="xs:token">
+         <xs:annotation>
+            <xs:documentation>The request attribute name the CsrfToken is set on. Default is to set to
+                CsrfToken.parameterName
+                </xs:documentation>
+         </xs:annotation>
+      </xs:attribute>
       <xs:attribute name="request-matcher-ref" type="xs:token">
          <xs:annotation>
             <xs:documentation>The RequestMatcher instance to be used to determine if CSRF should be applied. Default is

config/src/test/java/org/springframework/security/config/http/CsrfConfigTests.java

@@ -291,6 +291,15 @@ public class CsrfConfigTests {
 		// @formatter:on
 	}
 
+	@Test
+	public void getWhenUsingCsrfAndCustomRequestAttributeThenSetUsingCsrfAttrName() throws Exception {
+		this.spring.configLocations(this.xml("WithRequestAttrName")).autowire();
+		// @formatter:off
+		MvcResult result = this.mvc.perform(get("/ok")).andReturn();
+		assertThat(result.getRequest().getAttribute("csrf-attribute-name")).isInstanceOf(CsrfToken.class);
+		// @formatter:on
+	}
+
 	@Test
 	public void postWhenHasCsrfTokenButSessionExpiresThenRequestIsCancelledAfterSuccessfulAuthentication()
 			throws Exception {

config/src/test/resources/org/springframework/security/config/http/CsrfConfigTests-WithRequestAttrName.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2002-2018 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.
+  -->
+
+<b:beans xmlns:b="http://www.springframework.org/schema/beans"
+		 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xmlns="http://www.springframework.org/schema/security"
+		 xsi:schemaLocation="http://www.springframework.org/schema/security https://www.springframework.org/schema/security/spring-security.xsd
+		http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd">
+
+	<http auto-config="true">
+		<csrf request-attribute-name="csrf-attribute-name"/>
+	</http>
+
+	<b:import resource="CsrfConfigTests-shared-userservice.xml"/>
+</b:beans>

docs/modules/ROOT/pages/servlet/appendix/namespace/http.adoc

@@ -775,6 +775,10 @@ It is highly recommended to leave CSRF protection enabled.
 The CsrfTokenRepository to use.
 The default is `HttpSessionCsrfTokenRepository`.
 
+[[nsa-csrf-request-attribute-name]]
+* **request-attribute-name**
+Optional attribute that specifies the request attribute name to set the `CsrfToken` on.
+The default is `CsrfToken.parameterName`.
 
 [[nsa-csrf-request-matcher-ref]]
 * **request-matcher-ref**

web/src/main/java/org/springframework/security/web/csrf/CsrfFilter.java

@@ -87,6 +87,8 @@ public final class CsrfFilter extends OncePerRequestFilter {
 
 	private AccessDeniedHandler accessDeniedHandler = new AccessDeniedHandlerImpl();
 
+	private String csrfRequestAttributeName;
+
 	public CsrfFilter(CsrfTokenRepository csrfTokenRepository) {
 		Assert.notNull(csrfTokenRepository, "csrfTokenRepository cannot be null");
 		this.tokenRepository = csrfTokenRepository;
@@ -108,7 +110,9 @@ public final class CsrfFilter extends OncePerRequestFilter {
 			this.tokenRepository.saveToken(csrfToken, request, response);
 		}
 		request.setAttribute(CsrfToken.class.getName(), csrfToken);
-		request.setAttribute(csrfToken.getParameterName(), csrfToken);
+		String csrfAttrName = (this.csrfRequestAttributeName != null) ? this.csrfRequestAttributeName
+				: csrfToken.getParameterName();
+		request.setAttribute(csrfAttrName, csrfToken);
 		if (!this.requireCsrfProtectionMatcher.matches(request)) {
 			if (this.logger.isTraceEnabled()) {
 				this.logger.trace("Did not protect against CSRF since request did not match "
@@ -167,6 +171,18 @@ public final class CsrfFilter extends OncePerRequestFilter {
 		this.accessDeniedHandler = accessDeniedHandler;
 	}
 
+	/**
+	 * The {@link CsrfToken} is available as a request attribute named
+	 * {@code CsrfToken.class.getName()}. By default, an additional request attribute that
+	 * is the same as {@link CsrfToken#getParameterName()} is set. This attribute allows
+	 * overriding the additional attribute.
+	 * @param csrfRequestAttributeName the name of an additional request attribute with
+	 * the value of the CsrfToken. Default is {@link CsrfToken#getParameterName()}
+	 */
+	public void setCsrfRequestAttributeName(String csrfRequestAttributeName) {
+		this.csrfRequestAttributeName = csrfRequestAttributeName;
+	}
+
 	/**
 	 * Constant time comparison to prevent against timing attacks.
 	 * @param expected

web/src/test/java/org/springframework/security/web/csrf/CsrfFilterTests.java

@@ -48,6 +48,7 @@ import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.verifyZeroInteractions;
 
 /**
@@ -344,6 +345,23 @@ public class CsrfFilterTests {
 		assertThatIllegalArgumentException().isThrownBy(() -> this.filter.setAccessDeniedHandler(null));
 	}
 
+	// This ensures that the HttpSession on get requests unless the CsrfToken is used
+	@Test
+	public void doFilterWhenCsrfRequestAttributeNameThenNoCsrfTokenMethodInvokedOnGet()
+			throws ServletException, IOException {
+		CsrfFilter filter = createCsrfFilter(this.tokenRepository);
+		String csrfAttrName = "_csrf";
+		filter.setCsrfRequestAttributeName(csrfAttrName);
+		CsrfToken expectedCsrfToken = mock(CsrfToken.class);
+		given(this.tokenRepository.loadToken(this.request)).willReturn(expectedCsrfToken);
+
+		filter.doFilter(this.request, this.response, this.filterChain);
+
+		verifyNoInteractions(expectedCsrfToken);
+		CsrfToken tokenFromRequest = (CsrfToken) this.request.getAttribute(csrfAttrName);
+		assertThat(tokenFromRequest).isEqualTo(expectedCsrfToken);
+	}
+
 	private static CsrfTokenAssert assertToken(Object token) {
 		return new CsrfTokenAssert((CsrfToken) token);
 	}