Java tutorial
/* * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.security.auth.spi; import javax.security.auth.Subject; import javax.security.auth.AuthPermission; import javax.security.auth.callback.*; import javax.security.auth.login.*; import java.util.Map; /** * <p> Service-provider interface for authentication technology providers. * LoginModules are plugged in under applications to provide a particular * type of authentication. * * <p> While applications write to the {@code LoginContext} API, * authentication technology providers implement the * {@code LoginModule} interface. * A {@code Configuration} specifies the LoginModule(s) * to be used with a particular login application. Therefore different * LoginModules can be plugged in under the application without * requiring any modifications to the application itself. * * <p> The {@code LoginContext} is responsible for reading the * {@code Configuration} and instantiating the appropriate * LoginModules. Each {@code LoginModule} is initialized with * a {@code Subject}, a {@code CallbackHandler}, shared * {@code LoginModule} state, and LoginModule-specific options. * * The {@code Subject} represents the * {@code Subject} currently being authenticated and is updated * with relevant Credentials if authentication succeeds. * LoginModules use the {@code CallbackHandler} to * communicate with users. The {@code CallbackHandler} may be * used to prompt for usernames and passwords, for example. * Note that the {@code CallbackHandler} may be null. LoginModules * which absolutely require a {@code CallbackHandler} to authenticate * the {@code Subject} may throw a {@code LoginException}. * LoginModules optionally use the shared state to share information * or data among themselves. * * <p> The LoginModule-specific options represent the options * configured for this {@code LoginModule} by an administrator or user * in the login {@code Configuration}. * The options are defined by the {@code LoginModule} itself * and control the behavior within it. For example, a * {@code LoginModule} may define options to support debugging/testing * capabilities. Options are defined using a key-value syntax, * such as <i>debug=true</i>. The {@code LoginModule} * stores the options as a {@code Map} so that the values may * be retrieved using the key. Note that there is no limit to the number * of options a {@code LoginModule} chooses to define. * * <p> The calling application sees the authentication process as a single * operation. However, the authentication process within the * {@code LoginModule} proceeds in two distinct phases. * In the first phase, the LoginModule's * {@code login} method gets invoked by the LoginContext's * {@code login} method. The {@code login} * method for the {@code LoginModule} then performs * the actual authentication (prompt for and verify a password for example) * and saves its authentication status as private state * information. Once finished, the LoginModule's {@code login} * method either returns {@code true} (if it succeeded) or * {@code false} (if it should be ignored), or throws a * {@code LoginException} to specify a failure. * In the failure case, the {@code LoginModule} must not retry the * authentication or introduce delays. The responsibility of such tasks * belongs to the application. If the application attempts to retry * the authentication, the LoginModule's {@code login} method will be * called again. * * <p> In the second phase, if the LoginContext's overall authentication * succeeded (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL * LoginModules succeeded), then the {@code commit} * method for the {@code LoginModule} gets invoked. * The {@code commit} method for a {@code LoginModule} checks its * privately saved state to see if its own authentication succeeded. * If the overall {@code LoginContext} authentication succeeded * and the LoginModule's own authentication succeeded, then the * {@code commit} method associates the relevant * Principals (authenticated identities) and Credentials (authentication data * such as cryptographic keys) with the {@code Subject} * located within the {@code LoginModule}. * * <p> If the LoginContext's overall authentication failed (the relevant * REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules did not succeed), * then the {@code abort} method for each {@code LoginModule} * gets invoked. In this case, the {@code LoginModule} removes/destroys * any authentication state originally saved. * * <p> Logging out a {@code Subject} involves only one phase. * The {@code LoginContext} invokes the LoginModule's {@code logout} * method. The {@code logout} method for the {@code LoginModule} * then performs the logout procedures, such as removing Principals or * Credentials from the {@code Subject} or logging session information. * * <p> A {@code LoginModule} implementation must have a constructor with * no arguments. This allows classes which load the {@code LoginModule} * to instantiate it. * * @since 1.4 * @see javax.security.auth.login.LoginContext * @see javax.security.auth.login.Configuration */ public interface LoginModule { /** * Initialize this LoginModule. * * <p> This method is called by the {@code LoginContext} * after this {@code LoginModule} has been instantiated. * The purpose of this method is to initialize this * {@code LoginModule} with the relevant information. * If this {@code LoginModule} does not understand * any of the data stored in {@code sharedState} or * {@code options} parameters, they can be ignored. * * @param subject the {@code Subject} to be authenticated. * * @param callbackHandler a {@code CallbackHandler} for communicating * with the end user (prompting for usernames and * passwords, for example). * * @param sharedState state shared with other configured LoginModules. * * @param options options specified in the login * {@code Configuration} for this particular * {@code LoginModule}. */ void initialize(Subject subject, CallbackHandler callbackHandler, Map<String, ?> sharedState, Map<String, ?> options); /** * Method to authenticate a {@code Subject} (phase 1). * * <p> The implementation of this method authenticates * a {@code Subject}. For example, it may prompt for * {@code Subject} information such * as a username and password and then attempt to verify the password. * This method saves the result of the authentication attempt * as private state within the LoginModule. * * @exception LoginException if the authentication fails * * @return true if the authentication succeeded, or false if this * {@code LoginModule} should be ignored. */ boolean login() throws LoginException; /** * Method to commit the authentication process (phase 2). * * <p> This method is called if the LoginContext's * overall authentication succeeded * (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules * succeeded). * * <p> If this LoginModule's own authentication attempt * succeeded (checked by retrieving the private state saved by the * {@code login} method), then this method associates relevant * Principals and Credentials with the {@code Subject} located in the * {@code LoginModule}. If this LoginModule's own * authentication attempted failed, then this method removes/destroys * any state that was originally saved. * * @exception LoginException if the commit fails * * @return true if this method succeeded, or false if this * {@code LoginModule} should be ignored. */ boolean commit() throws LoginException; /** * Method to abort the authentication process (phase 2). * * <p> This method is called if the LoginContext's * overall authentication failed. * (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules * did not succeed). * * <p> If this LoginModule's own authentication attempt * succeeded (checked by retrieving the private state saved by the * {@code login} method), then this method cleans up any state * that was originally saved. * * @exception LoginException if the abort fails * * @return true if this method succeeded, or false if this * {@code LoginModule} should be ignored. */ boolean abort() throws LoginException; /** * Method which logs out a {@code Subject}. * * <p>An implementation of this method might remove/destroy a Subject's * Principals and Credentials. * * @exception LoginException if the logout fails * * @return true if this method succeeded, or false if this * {@code LoginModule} should be ignored. */ boolean logout() throws LoginException; }