Write and delete operations no longer work in the Cloud Foundry actuator support with Spring Security due to CSRF protection

[philwebb]

With #32622 we changed the security config from ignoring() to permitAll(). Unfortunately, the change also makes CSRF protection kick in which results in HTTP 401 responses.

Adding http.csrf((csrf) -> csrf.ignoringRequestMatchers(cloudFoundryRequest)); appears to fix the issue.

Updated code

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 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
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package org.springframework.boot.actuate.autoconfigure.cloudfoundry.servlet;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.actuate.autoconfigure.cloudfoundry.CloudFoundryWebEndpointDiscoverer;
import org.springframework.boot.actuate.autoconfigure.endpoint.condition.ConditionalOnAvailableEndpoint;
import org.springframework.boot.actuate.autoconfigure.health.HealthEndpointAutoConfiguration;
import org.springframework.boot.actuate.autoconfigure.info.InfoEndpointAutoConfiguration;
import org.springframework.boot.actuate.autoconfigure.web.servlet.ServletManagementContextAutoConfiguration;
import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
import org.springframework.boot.actuate.endpoint.invoke.ParameterValueMapper;
import org.springframework.boot.actuate.endpoint.web.EndpointMapping;
import org.springframework.boot.actuate.endpoint.web.EndpointMediaTypes;
import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
import org.springframework.boot.actuate.endpoint.web.PathMappedEndpoints;
import org.springframework.boot.actuate.health.HealthEndpoint;
import org.springframework.boot.actuate.health.HealthEndpointWebExtension;
import org.springframework.boot.actuate.info.GitInfoContributor;
import org.springframework.boot.actuate.info.InfoContributor;
import org.springframework.boot.actuate.info.InfoEndpoint;
import org.springframework.boot.actuate.info.InfoPropertiesInfoContributor;
import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBooleanProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnCloudPlatform;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.cloud.CloudPlatform;
import org.springframework.boot.info.GitProperties;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import org.springframework.core.env.Environment;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.security.config.annotation.web.WebSecurityConfigurer;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.builders.WebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityCustomizer;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.servlet.util.matcher.PathPatternRequestMatcher;
import org.springframework.security.web.util.matcher.OrRequestMatcher;
import org.springframework.security.web.util.matcher.RequestMatcher;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * {@link EnableAutoConfiguration Auto-configuration} to expose actuator endpoints for
 * Cloud Foundry to use.
 *
 * @author Madhura Bhave
 * @since 2.0.0
 */
@AutoConfiguration(after = { ServletManagementContextAutoConfiguration.class, HealthEndpointAutoConfiguration.class,
        InfoEndpointAutoConfiguration.class })
@ConditionalOnBooleanProperty(name = "management.cloudfoundry.enabled", matchIfMissing = true)
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)
@ConditionalOnClass(DispatcherServlet.class)
@ConditionalOnBean(DispatcherServlet.class)
@ConditionalOnCloudPlatform(CloudPlatform.CLOUD_FOUNDRY)
public class CloudFoundryActuatorAutoConfiguration {

    private static final String BASE_PATH = "/cloudfoundryapplication";

    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnAvailableEndpoint
    @ConditionalOnBean({ HealthEndpoint.class, HealthEndpointWebExtension.class })
    public CloudFoundryHealthEndpointWebExtension cloudFoundryHealthEndpointWebExtension(
            HealthEndpointWebExtension healthEndpointWebExtension) {
        return new CloudFoundryHealthEndpointWebExtension(healthEndpointWebExtension);
    }

    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnAvailableEndpoint
    @ConditionalOnBean({ InfoEndpoint.class, GitProperties.class })
    public CloudFoundryInfoEndpointWebExtension cloudFoundryInfoEndpointWebExtension(GitProperties properties,
            ObjectProvider<InfoContributor> infoContributors) {
        List<InfoContributor> contributors = infoContributors.orderedStream()
            .map((infoContributor) -> (infoContributor instanceof GitInfoContributor)
                    ? new GitInfoContributor(properties, InfoPropertiesInfoContributor.Mode.FULL) : infoContributor)
            .toList();
        return new CloudFoundryInfoEndpointWebExtension(new InfoEndpoint(contributors));
    }

    @Bean
    @SuppressWarnings("removal")
    public CloudFoundryWebEndpointServletHandlerMapping cloudFoundryWebEndpointServletHandlerMapping(
            ParameterValueMapper parameterMapper, EndpointMediaTypes endpointMediaTypes,
            RestTemplateBuilder restTemplateBuilder,
            org.springframework.boot.actuate.endpoint.web.annotation.ServletEndpointsSupplier servletEndpointsSupplier,
            org.springframework.boot.actuate.endpoint.web.annotation.ControllerEndpointsSupplier controllerEndpointsSupplier,
            ApplicationContext applicationContext) {
        CloudFoundryWebEndpointDiscoverer discoverer = new CloudFoundryWebEndpointDiscoverer(applicationContext,
                parameterMapper, endpointMediaTypes, null, Collections.emptyList(), Collections.emptyList(),
                Collections.emptyList());
        CloudFoundrySecurityInterceptor securityInterceptor = getSecurityInterceptor(restTemplateBuilder,
                applicationContext.getEnvironment());
        Collection<ExposableWebEndpoint> webEndpoints = discoverer.getEndpoints();
        List<ExposableEndpoint<?>> allEndpoints = new ArrayList<>();
        allEndpoints.addAll(webEndpoints);
        allEndpoints.addAll(servletEndpointsSupplier.getEndpoints());
        allEndpoints.addAll(controllerEndpointsSupplier.getEndpoints());
        return new CloudFoundryWebEndpointServletHandlerMapping(new EndpointMapping(BASE_PATH), webEndpoints,
                endpointMediaTypes, getCorsConfiguration(), securityInterceptor, allEndpoints);
    }

    private CloudFoundrySecurityInterceptor getSecurityInterceptor(RestTemplateBuilder restTemplateBuilder,
            Environment environment) {
        CloudFoundrySecurityService cloudfoundrySecurityService = getCloudFoundrySecurityService(restTemplateBuilder,
                environment);
        TokenValidator tokenValidator = new TokenValidator(cloudfoundrySecurityService);
        return new CloudFoundrySecurityInterceptor(tokenValidator, cloudfoundrySecurityService,
                environment.getProperty("vcap.application.application_id"));
    }

    private CloudFoundrySecurityService getCloudFoundrySecurityService(RestTemplateBuilder restTemplateBuilder,
            Environment environment) {
        String cloudControllerUrl = environment.getProperty("vcap.application.cf_api");
        boolean skipSslValidation = environment.getProperty("management.cloudfoundry.skip-ssl-validation",
                Boolean.class, false);
        return (cloudControllerUrl != null)
                ? new CloudFoundrySecurityService(restTemplateBuilder, cloudControllerUrl, skipSslValidation) : null;
    }

    private CorsConfiguration getCorsConfiguration() {
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin(CorsConfiguration.ALL);
        corsConfiguration.setAllowedMethods(Arrays.asList(HttpMethod.GET.name(), HttpMethod.POST.name()));
        corsConfiguration
            .setAllowedHeaders(Arrays.asList(HttpHeaders.AUTHORIZATION, "X-Cf-App-Instance", HttpHeaders.CONTENT_TYPE));
        return corsConfiguration;
    }

    /**
     * {@link WebSecurityConfigurer} to tell Spring Security to permit cloudfoundry
     * specific paths. The Cloud foundry endpoints are protected by their own security
     * interceptor.
     */
    @ConditionalOnClass({ WebSecurityCustomizer.class, WebSecurity.class })
    @Configuration(proxyBeanMethods = false)
    public static class IgnoredCloudFoundryPathsWebSecurityConfiguration {

        private static final int FILTER_CHAIN_ORDER = -1;

        @Bean
        @Order(FILTER_CHAIN_ORDER)
        SecurityFilterChain cloudFoundrySecurityFilterChain(HttpSecurity http,
                CloudFoundryWebEndpointServletHandlerMapping handlerMapping) throws Exception {
            RequestMatcher cloudFoundryRequest = getRequestMatcher(handlerMapping);
            http.csrf((csrf) -> csrf.ignoringRequestMatchers(cloudFoundryRequest));
            http.securityMatchers((matches) -> matches.requestMatchers(cloudFoundryRequest))
                .authorizeHttpRequests((authorize) -> authorize.anyRequest().permitAll());
            return http.build();
        }

        private RequestMatcher getRequestMatcher(CloudFoundryWebEndpointServletHandlerMapping handlerMapping) {
            PathMappedEndpoints endpoints = new PathMappedEndpoints(BASE_PATH, handlerMapping::getAllEndpoints);
            List<RequestMatcher> matchers = new ArrayList<>();
            endpoints.getAllPaths().forEach((path) -> matchers.add(pathMatcher(path + "/**")));
            matchers.add(pathMatcher(BASE_PATH));
            matchers.add(pathMatcher(BASE_PATH + "/"));
            return new OrRequestMatcher(matchers);
        }

        private PathPatternRequestMatcher pathMatcher(String path) {
            return PathPatternRequestMatcher.withDefaults().matcher(path);
        }

    }

}