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1 /*
2  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 
26 package sun.security.util;
27 
28 import java.util.HashSet;
29 import java.util.Set;
30 import java.util.Arrays;
31 import java.util.Collection;
32 import java.util.regex.Pattern;
33 
34 /**
35  * The class decomposes standard algorithms into sub-elements.
36  */
37 public class AlgorithmDecomposer {
38 
39     // '(?<!padd)in': match 'in' but not preceded with 'padd'.
40     private static final Pattern PATTERN =
41             Pattern.compile("with|and|(?<!padd)in", Pattern.CASE_INSENSITIVE);
42 
decomposeImpl(String algorithm)43     private static Set<String> decomposeImpl(String algorithm) {
44         Set<String> elements = new HashSet<>();
45 
46         // algorithm/mode/padding
47         String[] transTokens = algorithm.split("/");
48 
49         for (String transToken : transTokens) {
50             if (transToken == null || transToken.isEmpty()) {
51                 continue;
52             }
53 
54             // PBEWith<digest>And<encryption>
55             // PBEWith<prf>And<encryption>
56             // OAEPWith<digest>And<mgf>Padding
57             // <digest>with<encryption>
58             // <digest>with<encryption>and<mgf>
59             // <digest>with<encryption>in<format>
60             String[] tokens = PATTERN.split(transToken);
61 
62             for (String token : tokens) {
63                 if (token == null || token.isEmpty()) {
64                     continue;
65                 }
66 
67                 elements.add(token);
68             }
69         }
70         return elements;
71     }
72 
73     /**
74      * Decompose the standard algorithm name into sub-elements.
75      * <p>
76      * For example, we need to decompose "SHA1WithRSA" into "SHA1" and "RSA"
77      * so that we can check the "SHA1" and "RSA" algorithm constraints
78      * separately.
79      * <p>
80      * Please override the method if need to support more name pattern.
81      */
decompose(String algorithm)82     public Set<String> decompose(String algorithm) {
83         if (algorithm == null || algorithm.isEmpty()) {
84             return new HashSet<>();
85         }
86 
87         Set<String> elements = decomposeImpl(algorithm);
88 
89         // In Java standard algorithm name specification, for different
90         // purpose, the SHA-1 and SHA-2 algorithm names are different. For
91         // example, for MessageDigest, the standard name is "SHA-256", while
92         // for Signature, the digest algorithm component is "SHA256" for
93         // signature algorithm "SHA256withRSA". So we need to check both
94         // "SHA-256" and "SHA256" to make the right constraint checking.
95 
96         // handle special name: SHA-1 and SHA1
97         if (elements.contains("SHA1") && !elements.contains("SHA-1")) {
98             elements.add("SHA-1");
99         }
100         if (elements.contains("SHA-1") && !elements.contains("SHA1")) {
101             elements.add("SHA1");
102         }
103 
104         // handle special name: SHA-224 and SHA224
105         if (elements.contains("SHA224") && !elements.contains("SHA-224")) {
106             elements.add("SHA-224");
107         }
108         if (elements.contains("SHA-224") && !elements.contains("SHA224")) {
109             elements.add("SHA224");
110         }
111 
112         // handle special name: SHA-256 and SHA256
113         if (elements.contains("SHA256") && !elements.contains("SHA-256")) {
114             elements.add("SHA-256");
115         }
116         if (elements.contains("SHA-256") && !elements.contains("SHA256")) {
117             elements.add("SHA256");
118         }
119 
120         // handle special name: SHA-384 and SHA384
121         if (elements.contains("SHA384") && !elements.contains("SHA-384")) {
122             elements.add("SHA-384");
123         }
124         if (elements.contains("SHA-384") && !elements.contains("SHA384")) {
125             elements.add("SHA384");
126         }
127 
128         // handle special name: SHA-512 and SHA512
129         if (elements.contains("SHA512") && !elements.contains("SHA-512")) {
130             elements.add("SHA-512");
131         }
132         if (elements.contains("SHA-512") && !elements.contains("SHA512")) {
133             elements.add("SHA512");
134         }
135 
136         return elements;
137     }
138 
139     /**
140      * Get aliases of the specified algorithm.
141      *
142      * May support more algorithms in the future.
143      */
getAliases(String algorithm)144     public static Collection<String> getAliases(String algorithm) {
145         String[] aliases;
146         if (algorithm.equalsIgnoreCase("DH") ||
147                 algorithm.equalsIgnoreCase("DiffieHellman")) {
148             aliases = new String[] {"DH", "DiffieHellman"};
149         } else {
150             aliases = new String[] {algorithm};
151         }
152 
153         return Arrays.asList(aliases);
154     }
155 
hasLoop(Set<String> elements, String find, String replace)156     private static void hasLoop(Set<String> elements, String find, String replace) {
157         if (elements.contains(find)) {
158             if (!elements.contains(replace)) {
159                 elements.add(replace);
160             }
161             elements.remove(find);
162         }
163     }
164 
165     /*
166      * This decomposes a standard name into sub-elements with a consistent
167      * message digest algorithm name to avoid overly complicated checking.
168      */
decomposeOneHash(String algorithm)169     public static Set<String> decomposeOneHash(String algorithm) {
170         if (algorithm == null || algorithm.isEmpty()) {
171             return new HashSet<>();
172         }
173 
174         Set<String> elements = decomposeImpl(algorithm);
175 
176         hasLoop(elements, "SHA-1", "SHA1");
177         hasLoop(elements, "SHA-224", "SHA224");
178         hasLoop(elements, "SHA-256", "SHA256");
179         hasLoop(elements, "SHA-384", "SHA384");
180         hasLoop(elements, "SHA-512", "SHA512");
181 
182         return elements;
183     }
184 
185     /*
186      * The provided message digest algorithm name will return a consistent
187      * naming scheme.
188      */
hashName(String algorithm)189     public static String hashName(String algorithm) {
190         return algorithm.replace("-", "");
191     }
192 }
193