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1   /*
2    * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch>
3    * and other copyright owners as documented in the project's IP log.
4    *
5    * This program and the accompanying materials are made available
6    * under the terms of the Eclipse Distribution License v1.0 which
7    * accompanies this distribution, is reproduced below, and is
8    * available at http://www.eclipse.org/org/documents/edl-v10.php
9    *
10   * All rights reserved.
11   *
12   * Redistribution and use in source and binary forms, with or
13   * without modification, are permitted provided that the following
14   * conditions are met:
15   *
16   * - Redistributions of source code must retain the above copyright
17   *   notice, this list of conditions and the following disclaimer.
18   *
19   * - Redistributions in binary form must reproduce the above
20   *   copyright notice, this list of conditions and the following
21   *   disclaimer in the documentation and/or other materials provided
22   *   with the distribution.
23   *
24   * - Neither the name of the Eclipse Foundation, Inc. nor the
25   *   names of its contributors may be used to endorse or promote
26   *   products derived from this software without specific prior
27   *   written permission.
28   *
29   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42   */
43  package org.eclipse.jgit.transport.sshd;
44  
45  import java.io.IOException;
46  import java.security.GeneralSecurityException;
47  
48  import org.eclipse.jgit.transport.URIish;
49  
50  /**
51   * A {@code KeyPasswordProvider} provides passwords for encrypted private keys.
52   *
53   * @since 5.2
54   */
55  public interface KeyPasswordProvider {
56  
57  	/**
58  	 * Obtains a passphrase to use to decrypt an ecrypted private key. Returning
59  	 * {@code null} or an empty array will skip this key. To cancel completely,
60  	 * the operation should raise
61  	 * {@link java.util.concurrent.CancellationException}.
62  	 *
63  	 * @param uri
64  	 *            identifying the key resource that is being attempted to be
65  	 *            loaded
66  	 * @param attempt
67  	 *            the number of previous attempts to get a passphrase; >= 0
68  	 * @return the passphrase
69  	 * @throws IOException
70  	 *             if no password can be obtained
71  	 */
72  	char[] getPassphrase(URIish uri, int attempt) throws IOException;
73  
74  	/**
75  	 * Define the maximum number of attempts to get a passphrase that should be
76  	 * attempted for one identity resource through this provider.
77  	 *
78  	 * @param maxNumberOfAttempts
79  	 *            number of times to ask for a passphrase;
80  	 *            {@link IllegalArgumentException} may be thrown if <= 0
81  	 */
82  	void setAttempts(int maxNumberOfAttempts);
83  
84  	/**
85  	 * Gets the maximum number of attempts to get a passphrase that should be
86  	 * attempted for one identity resource through this provider. The default
87  	 * return 1.
88  	 *
89  	 * @return the number of times to ask for a passphrase; should be >= 1.
90  	 */
91  	default int getAttempts() {
92  		return 1;
93  	}
94  
95  	/**
96  	 * Invoked after a key has been loaded. If this raises an exception, the
97  	 * original {@code error} is lost unless it is attached to that exception.
98  	 *
99  	 * @param uri
100 	 *            identifying the key resource the key was attempted to be
101 	 *            loaded from
102 	 * @param attempt
103 	 *            the number of times {@link #getPassphrase(URIish, int)} had
104 	 *            been called; zero indicates that {@code uri} refers to a
105 	 *            non-encrypted key
106 	 * @param error
107 	 *            {@code null} if the key was loaded successfully; otherwise an
108 	 *            exception indicating why the key could not be loaded
109 	 * @return {@code true} to re-try again; {@code false} to re-raise the
110 	 *         {@code error} exception; Ignored if the key was loaded
111 	 *         successfully, i.e., if {@code error == null}.
112 	 * @throws IOException
113 	 * @throws GeneralSecurityException
114 	 */
115 	boolean keyLoaded(URIish uri, int attempt, Exception error)
116 			throws IOException, GeneralSecurityException;
117 }