org.springframework.security.config.annotation.web.configurers.CsrfConfigurer.java Source code

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/*
 * Copyright 2002-2019 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 org.springframework.security.config.annotation.web.configurers;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.springframework.context.ApplicationContext;
import org.springframework.http.HttpMethod;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.config.annotation.web.AbstractRequestMatcherRegistry;
import org.springframework.security.config.annotation.web.HttpSecurityBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.access.AccessDeniedHandler;
import org.springframework.security.web.access.AccessDeniedHandlerImpl;
import org.springframework.security.web.access.DelegatingAccessDeniedHandler;
import org.springframework.security.web.authentication.session.SessionAuthenticationStrategy;
import org.springframework.security.web.csrf.CsrfAuthenticationStrategy;
import org.springframework.security.web.csrf.CsrfFilter;
import org.springframework.security.web.csrf.CsrfLogoutHandler;
import org.springframework.security.web.csrf.CsrfTokenRepository;
import org.springframework.security.web.csrf.HttpSessionCsrfTokenRepository;
import org.springframework.security.web.csrf.LazyCsrfTokenRepository;
import org.springframework.security.web.csrf.MissingCsrfTokenException;
import org.springframework.security.web.servlet.util.matcher.MvcRequestMatcher;
import org.springframework.security.web.session.InvalidSessionAccessDeniedHandler;
import org.springframework.security.web.session.InvalidSessionStrategy;
import org.springframework.security.web.util.matcher.AndRequestMatcher;
import org.springframework.security.web.util.matcher.NegatedRequestMatcher;
import org.springframework.security.web.util.matcher.OrRequestMatcher;
import org.springframework.security.web.util.matcher.RequestMatcher;
import org.springframework.util.Assert;

/**
 * Adds
 * <a href="https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)" >CSRF</a>
 * protection for the methods as specified by
 * {@link #requireCsrfProtectionMatcher(RequestMatcher)}.
 *
 * <h2>Security Filters</h2>
 *
 * The following Filters are populated
 *
 * <ul>
 * <li>{@link CsrfFilter}</li>
 * </ul>
 *
 * <h2>Shared Objects Created</h2>
 *
 * No shared objects are created.
 *
 * <h2>Shared Objects Used</h2>
 *
 * <ul>
 * <li>{@link ExceptionHandlingConfigurer#accessDeniedHandler(AccessDeniedHandler)} is
 * used to determine how to handle CSRF attempts</li>
 * <li>{@link InvalidSessionStrategy}</li>
 * </ul>
 *
 * @author Rob Winch
 * @since 3.2
 */
public final class CsrfConfigurer<H extends HttpSecurityBuilder<H>>
        extends AbstractHttpConfigurer<CsrfConfigurer<H>, H> {
    private CsrfTokenRepository csrfTokenRepository = new LazyCsrfTokenRepository(
            new HttpSessionCsrfTokenRepository());
    private RequestMatcher requireCsrfProtectionMatcher = CsrfFilter.DEFAULT_CSRF_MATCHER;
    private List<RequestMatcher> ignoredCsrfProtectionMatchers = new ArrayList<>();
    private SessionAuthenticationStrategy sessionAuthenticationStrategy;
    private final ApplicationContext context;

    /**
     * Creates a new instance
     * @see HttpSecurity#csrf()
     */
    public CsrfConfigurer(ApplicationContext context) {
        this.context = context;
    }

    /**
     * Specify the {@link CsrfTokenRepository} to use. The default is an
     * {@link HttpSessionCsrfTokenRepository} wrapped by {@link LazyCsrfTokenRepository}.
     *
     * @param csrfTokenRepository the {@link CsrfTokenRepository} to use
     * @return the {@link CsrfConfigurer} for further customizations
     */
    public CsrfConfigurer<H> csrfTokenRepository(CsrfTokenRepository csrfTokenRepository) {
        Assert.notNull(csrfTokenRepository, "csrfTokenRepository cannot be null");
        this.csrfTokenRepository = csrfTokenRepository;
        return this;
    }

    /**
     * Specify the {@link RequestMatcher} to use for determining when CSRF should be
     * applied. The default is to ignore GET, HEAD, TRACE, OPTIONS and process all other
     * requests.
     *
     * @param requireCsrfProtectionMatcher the {@link RequestMatcher} to use
     * @return the {@link CsrfConfigurer} for further customizations
     */
    public CsrfConfigurer<H> requireCsrfProtectionMatcher(RequestMatcher requireCsrfProtectionMatcher) {
        Assert.notNull(requireCsrfProtectionMatcher, "requireCsrfProtectionMatcher cannot be null");
        this.requireCsrfProtectionMatcher = requireCsrfProtectionMatcher;
        return this;
    }

    /**
     * <p>
     * Allows specifying {@link HttpServletRequest} that should not use CSRF Protection
     * even if they match the {@link #requireCsrfProtectionMatcher(RequestMatcher)}.
     * </p>
     *
     * <p>
     * For example, the following configuration will ensure CSRF protection ignores:
     * </p>
     * <ul>
     * <li>Any GET, HEAD, TRACE, OPTIONS (this is the default)</li>
     * <li>We also explicitly state to ignore any request that starts with "/sockjs/"</li>
     * </ul>
     *
     * <pre>
     * http
     *     .csrf()
     *         .ignoringAntMatchers("/sockjs/**")
     *         .and()
     *     ...
     * </pre>
     *
     * @since 4.0
     */
    public CsrfConfigurer<H> ignoringAntMatchers(String... antPatterns) {
        return new IgnoreCsrfProtectionRegistry(this.context).antMatchers(antPatterns).and();
    }

    /**
     * <p>
     * Allows specifying {@link HttpServletRequest}s that should not use CSRF Protection
     * even if they match the {@link #requireCsrfProtectionMatcher(RequestMatcher)}.
     * </p>
     *
     * <p>
     * For example, the following configuration will ensure CSRF protection ignores:
     * </p>
     * <ul>
     * <li>Any GET, HEAD, TRACE, OPTIONS (this is the default)</li>
     * <li>We also explicitly state to ignore any request that has a "X-Requested-With: XMLHttpRequest" header</li>
     * </ul>
     *
     * <pre>
     * http
     *     .csrf()
     *         .ignoringRequestMatchers(request -> "XMLHttpRequest".equals(request.getHeader("X-Requested-With")))
     *         .and()
     *     ...
     * </pre>
     *
     * @since 5.1
     */
    public CsrfConfigurer<H> ignoringRequestMatchers(RequestMatcher... requestMatchers) {
        return new IgnoreCsrfProtectionRegistry(this.context).requestMatchers(requestMatchers).and();
    }

    /**
     * <p>
     * Specify the {@link SessionAuthenticationStrategy} to use. The default is a
     * {@link CsrfAuthenticationStrategy}.
     * </p>
     *
     * @author Michael Vitz
     * @since 5.2
     *
     * @param sessionAuthenticationStrategy the {@link SessionAuthenticationStrategy} to use
     * @return the {@link CsrfConfigurer} for further customizations
     */
    public CsrfConfigurer<H> sessionAuthenticationStrategy(
            SessionAuthenticationStrategy sessionAuthenticationStrategy) {
        Assert.notNull(sessionAuthenticationStrategy, "sessionAuthenticationStrategy cannot be null");
        this.sessionAuthenticationStrategy = sessionAuthenticationStrategy;
        return this;
    }

    @SuppressWarnings("unchecked")
    @Override
    public void configure(H http) throws Exception {
        CsrfFilter filter = new CsrfFilter(this.csrfTokenRepository);
        RequestMatcher requireCsrfProtectionMatcher = getRequireCsrfProtectionMatcher();
        if (requireCsrfProtectionMatcher != null) {
            filter.setRequireCsrfProtectionMatcher(requireCsrfProtectionMatcher);
        }
        AccessDeniedHandler accessDeniedHandler = createAccessDeniedHandler(http);
        if (accessDeniedHandler != null) {
            filter.setAccessDeniedHandler(accessDeniedHandler);
        }
        LogoutConfigurer<H> logoutConfigurer = http.getConfigurer(LogoutConfigurer.class);
        if (logoutConfigurer != null) {
            logoutConfigurer.addLogoutHandler(new CsrfLogoutHandler(this.csrfTokenRepository));
        }
        SessionManagementConfigurer<H> sessionConfigurer = http.getConfigurer(SessionManagementConfigurer.class);
        if (sessionConfigurer != null) {
            sessionConfigurer.addSessionAuthenticationStrategy(getSessionAuthenticationStrategy());
        }
        filter = postProcess(filter);
        http.addFilter(filter);
    }

    /**
     * Gets the final {@link RequestMatcher} to use by combining the
     * {@link #requireCsrfProtectionMatcher(RequestMatcher)} and any {@link #ignore()}.
     *
     * @return the {@link RequestMatcher} to use
     */
    private RequestMatcher getRequireCsrfProtectionMatcher() {
        if (this.ignoredCsrfProtectionMatchers.isEmpty()) {
            return this.requireCsrfProtectionMatcher;
        }
        return new AndRequestMatcher(this.requireCsrfProtectionMatcher,
                new NegatedRequestMatcher(new OrRequestMatcher(this.ignoredCsrfProtectionMatchers)));
    }

    /**
     * Gets the default {@link AccessDeniedHandler} from the
     * {@link ExceptionHandlingConfigurer#getAccessDeniedHandler()} or create a
     * {@link AccessDeniedHandlerImpl} if not available.
     *
     * @param http the {@link HttpSecurityBuilder}
     * @return the {@link AccessDeniedHandler}
     */
    @SuppressWarnings("unchecked")
    private AccessDeniedHandler getDefaultAccessDeniedHandler(H http) {
        ExceptionHandlingConfigurer<H> exceptionConfig = http.getConfigurer(ExceptionHandlingConfigurer.class);
        AccessDeniedHandler handler = null;
        if (exceptionConfig != null) {
            handler = exceptionConfig.getAccessDeniedHandler();
        }
        if (handler == null) {
            handler = new AccessDeniedHandlerImpl();
        }
        return handler;
    }

    /**
     * Gets the default {@link InvalidSessionStrategy} from the
     * {@link SessionManagementConfigurer#getInvalidSessionStrategy()} or null if not
     * available.
     *
     * @param http the {@link HttpSecurityBuilder}
     * @return the {@link InvalidSessionStrategy}
     */
    @SuppressWarnings("unchecked")
    private InvalidSessionStrategy getInvalidSessionStrategy(H http) {
        SessionManagementConfigurer<H> sessionManagement = http.getConfigurer(SessionManagementConfigurer.class);
        if (sessionManagement == null) {
            return null;
        }
        return sessionManagement.getInvalidSessionStrategy();
    }

    /**
     * Creates the {@link AccessDeniedHandler} from the result of
     * {@link #getDefaultAccessDeniedHandler(HttpSecurityBuilder)} and
     * {@link #getInvalidSessionStrategy(HttpSecurityBuilder)}. If
     * {@link #getInvalidSessionStrategy(HttpSecurityBuilder)} is non-null, then a
     * {@link DelegatingAccessDeniedHandler} is used in combination with
     * {@link InvalidSessionAccessDeniedHandler} and the
     * {@link #getDefaultAccessDeniedHandler(HttpSecurityBuilder)}. Otherwise, only
     * {@link #getDefaultAccessDeniedHandler(HttpSecurityBuilder)} is used.
     *
     * @param http the {@link HttpSecurityBuilder}
     * @return the {@link AccessDeniedHandler}
     */
    private AccessDeniedHandler createAccessDeniedHandler(H http) {
        InvalidSessionStrategy invalidSessionStrategy = getInvalidSessionStrategy(http);
        AccessDeniedHandler defaultAccessDeniedHandler = getDefaultAccessDeniedHandler(http);
        if (invalidSessionStrategy == null) {
            return defaultAccessDeniedHandler;
        }

        InvalidSessionAccessDeniedHandler invalidSessionDeniedHandler = new InvalidSessionAccessDeniedHandler(
                invalidSessionStrategy);
        LinkedHashMap<Class<? extends AccessDeniedException>, AccessDeniedHandler> handlers = new LinkedHashMap<>();
        handlers.put(MissingCsrfTokenException.class, invalidSessionDeniedHandler);
        return new DelegatingAccessDeniedHandler(handlers, defaultAccessDeniedHandler);
    }

    /**
     * Gets the {@link SessionAuthenticationStrategy} to use. If none was set by the user a
     * {@link CsrfAuthenticationStrategy} is created.
     *
     * @author Michael Vitz
     * @since 5.2
     *
     * @return the {@link SessionAuthenticationStrategy}
     */
    private SessionAuthenticationStrategy getSessionAuthenticationStrategy() {
        if (sessionAuthenticationStrategy != null) {
            return sessionAuthenticationStrategy;
        } else {
            return new CsrfAuthenticationStrategy(this.csrfTokenRepository);
        }
    }

    /**
     * Allows registering {@link RequestMatcher} instances that should be ignored (even if
     * the {@link HttpServletRequest} matches the
     * {@link CsrfConfigurer#requireCsrfProtectionMatcher(RequestMatcher)}.
     *
     * @author Rob Winch
     * @since 4.0
     */
    private class IgnoreCsrfProtectionRegistry
            extends AbstractRequestMatcherRegistry<IgnoreCsrfProtectionRegistry> {

        /**
         * @param context
         */
        private IgnoreCsrfProtectionRegistry(ApplicationContext context) {
            setApplicationContext(context);
        }

        @Override
        public MvcMatchersIgnoreCsrfProtectionRegistry mvcMatchers(HttpMethod method, String... mvcPatterns) {
            List<MvcRequestMatcher> mvcMatchers = createMvcMatchers(method, mvcPatterns);
            CsrfConfigurer.this.ignoredCsrfProtectionMatchers.addAll(mvcMatchers);
            return new MvcMatchersIgnoreCsrfProtectionRegistry(getApplicationContext(), mvcMatchers);
        }

        @Override
        public MvcMatchersIgnoreCsrfProtectionRegistry mvcMatchers(String... mvcPatterns) {
            return mvcMatchers(null, mvcPatterns);
        }

        public CsrfConfigurer<H> and() {
            return CsrfConfigurer.this;
        }

        @Override
        protected IgnoreCsrfProtectionRegistry chainRequestMatchers(List<RequestMatcher> requestMatchers) {
            CsrfConfigurer.this.ignoredCsrfProtectionMatchers.addAll(requestMatchers);
            return this;
        }
    }

    /**
     * An {@link IgnoreCsrfProtectionRegistry} that allows optionally configuring the
     * {@link MvcRequestMatcher#setMethod(HttpMethod)}
     *
     * @author Rob Winch
     */
    private final class MvcMatchersIgnoreCsrfProtectionRegistry extends IgnoreCsrfProtectionRegistry {
        private final List<MvcRequestMatcher> mvcMatchers;

        private MvcMatchersIgnoreCsrfProtectionRegistry(ApplicationContext context,
                List<MvcRequestMatcher> mvcMatchers) {
            super(context);
            this.mvcMatchers = mvcMatchers;
        }

        public IgnoreCsrfProtectionRegistry servletPath(String servletPath) {
            for (MvcRequestMatcher matcher : this.mvcMatchers) {
                matcher.setServletPath(servletPath);
            }
            return this;
        }
    }
}