SecurityContextUtil.java

/*
 * Copyright 2020 Global Crop Diversity Trust
 *
 * 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
 *
 *   http://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.genesys.blocks.security;

import java.util.Arrays;
import java.util.List;

import org.genesys.blocks.security.model.AclSid;
import org.genesys.blocks.security.model.BasicUser;
import org.genesys.blocks.util.CurrentApplicationContext;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.security.access.PermissionEvaluator;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.oauth2.jwt.Jwt;
import org.springframework.security.oauth2.server.resource.authentication.AbstractOAuth2TokenAuthenticationToken;
import org.springframework.security.web.authentication.preauth.PreAuthenticatedAuthenticationToken;

import lombok.extern.slf4j.Slf4j;

/**
 * The Class SecurityContextUtil.
 */
@Slf4j
public class SecurityContextUtil {

	/** The permission evaluator. */
	private static PermissionEvaluator permissionEvaluator;

	private final static Authentication ANONYMOUS_AUTH = new PreAuthenticatedAuthenticationToken("Anyone", null, Arrays.asList(new SimpleGrantedAuthority("ROLE_EVERYONE")));

	// Context initialization
	static {
		updatePermissionEvaluator();
	}

	/**
	 * Try to obtain permissionEvaluator bean from context
	 * 
	 * @return true if obtained, false if not obtained.
	 */
	private static synchronized boolean updatePermissionEvaluator() {
		return (permissionEvaluator = updateBean(PermissionEvaluator.class)) != null;
	}

	/**
	 * Update bean.
	 *
	 * @param <T> the generic type
	 * @param clazz the clazz
	 * @return the t
	 */
	static final <T> T updateBean(Class<T> clazz) {
		ApplicationContext context = CurrentApplicationContext.getContext();
		if (context != null) {
			try {
				return context.getBean(clazz);
			} catch (BeansException e) {
				log.warn("Could not find {} instance in your context: {}", clazz, e.getMessage());
			}
		} else {
			log.warn("You should initialize a bean instance of org.genesys.blocks.util.CurrentApplicationContext in your context");
		}
		return null;
	}

	/**
	 * Gets the username.
	 *
	 * @return the username
	 */
	public static String getUsername() {
		final Authentication auth = SecurityContextHolder.getContext().getAuthentication();

		if (auth != null && auth.getPrincipal() instanceof UserDetails) {
			return ((UserDetails) auth.getPrincipal()).getUsername();
		} else {
			return null;
		}
	}

	/**
	 * Gets the me.
	 *
	 * @param <T> the generic type
	 * @return current user
	 */
	@SuppressWarnings("unchecked")
	public static <T extends BasicUser<?>> T getMe() {
		final Authentication auth = SecurityContextHolder.getContext().getAuthentication();

		if (auth != null) {
			Object principal = auth.getPrincipal();
			if (principal instanceof BasicUser) {
				return (T) principal;
			} else {
				log.warn("Principal {} is not BasicUser, but type {}", principal, principal.getClass());
			}
		}

		return null;
	}

	/**
	 * Gets the current principal (User or OAuthClient).
	 *
	 * @param <T> the generic type
	 * @return the current security principal
	 */
	@SuppressWarnings("unchecked")
	public static <T extends AclSid> T getCurrentUser() {
		final Authentication authentication = SecurityContextHolder.getContext().getAuthentication();

		if (authentication != null) {
			Object principal = authentication.getPrincipal();
			if (principal instanceof AclSid) {
				return (T) principal;
			} else {
				log.warn("Principal {} is not AclSid, but type {}. Auth of type {}", principal, principal.getClass(), authentication.getClass());
			}
		}

		return null;
	}

	/**
	 * Checks for role.
	 *
	 * @param role the role
	 * @return true, if successful
	 */
	public static boolean hasRole(String role) {
		final Authentication auth = SecurityContextHolder.getContext().getAuthentication();
		if (auth != null) {
			for (GrantedAuthority authority : auth.getAuthorities()) {
				if (authority.getAuthority().equals("ROLE_" + role)) {
					return true;
				}
			}
		}
		return false;
	}

	/**
	 * Checks if any role is granted.
	 *
	 * @param roles the roles
	 * @return true, if successful
	 */
	public static boolean hasAnyRole(String... roles) {
		final Authentication auth = SecurityContextHolder.getContext().getAuthentication();
		if (auth != null) {
			for (GrantedAuthority authority : auth.getAuthorities()) {
				for (String role : roles) {
					if (authority.getAuthority().equals("ROLE_" + role)) {
						return true;
					}
				}
			}
		}
		return false;
	}

	/**
	 * Check if authority is granted.
	 *
	 * @param authorityName the authority name
	 * @return true, if successful
	 */
	public static boolean hasAuthority(String authorityName) {
		final Authentication auth = SecurityContextHolder.getContext().getAuthentication();
		if (auth != null) {
			for (GrantedAuthority authority : auth.getAuthorities()) {
				if (authority.getAuthority().equals(authorityName)) {
					return true;
				}
			}
		}
		return false;
	}

	/**
	 * Checks for permission.
	 *
	 * @param targetDomainObject the target domain object
	 * @param permission the permission
	 * @return true, if successful
	 */
	public static boolean hasPermission(Object targetDomainObject, Object permission) {
		final Authentication auth = SecurityContextHolder.getContext().getAuthentication();
		return hasPermission(auth, targetDomainObject, permission);
	}

	/**
	 * Checks for permission.
	 *
	 * @param auth authentication object
	 * @param targetDomainObject the target domain object
	 * @param permission the permission
	 * @return true, if successful
	 */
	public static boolean hasPermission(final Authentication auth, Object targetDomainObject, Object permission) {
		if (permissionEvaluator == null) {
			log.info("permissionEvaluator not available. Checking context again");
			if (!updatePermissionEvaluator()) {
				log.warn("permissionEvaluator not available. No permissions.");
				return false;
			}
		}

		if (auth != null) {
			return permissionEvaluator.hasPermission(auth, targetDomainObject, permission);
		} else {
			return false;
		}
	}

	/**
	 * Check if ROLE_EVERYONE has permission on target object.
	 *
	 * @param targetDomainObject the target domain object
	 * @param permission the permission
	 * @return true, if successful
	 */
	public static boolean anyoneHasPermission(Object targetDomainObject, Object permission) {
		if (permissionEvaluator == null) {
			log.info("permissionEvaluator not available. Checking context again");
			if (!updatePermissionEvaluator()) {
				log.warn("permissionEvaluator not available. No permissions.");
				return false;
			}
		}

		if (ANONYMOUS_AUTH != null) {
			return permissionEvaluator.hasPermission(ANONYMOUS_AUTH, targetDomainObject, permission);
		} else {
			return false;
		}
	}

	/**
	 * Gets the OAuth Client ID of the current authentication object.
	 *
	 * @return the OAuth client ID
	 */
	public static String getOAuthClientId() {
		final Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
		if (authentication instanceof AbstractOAuth2TokenAuthenticationToken<?>) {
			var oauthAuth = (AbstractOAuth2TokenAuthenticationToken<?>) authentication;
			log.debug("OAuth authentication: {}", oauthAuth);
			var token = (Jwt) oauthAuth.getToken();
			var aud = token.getClaim("aud");
			if (aud instanceof List<?> && !((List<?>)aud).isEmpty()) {
				return String.valueOf(((List<?>) aud).get(0));
			}
			return String.valueOf(aud);
		} else if (authentication == null) {
			// No authentication
			return null;
		} else {
			// Not OAuth authentication
			log.warn("TODO {} {}", authentication.getClass(), authentication);
			return null;
		}
	}
}