1/*
2 * Copyright (c) 2015, 2016, 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
26package sun.security.util;
27
28import java.util.HashSet;
29import java.util.Set;
30import java.util.regex.Pattern;
31
32/**
33 * The class decomposes standard algorithms into sub-elements.
34 */
35public class AlgorithmDecomposer {
36
37    private static final Pattern transPattern = Pattern.compile("/");
38    private static final Pattern pattern =
39                    Pattern.compile("with|and", Pattern.CASE_INSENSITIVE);
40
41    private static Set<String> decomposeImpl(String algorithm) {
42
43        // algorithm/mode/padding
44        String[] transTockens = transPattern.split(algorithm);
45
46        Set<String> elements = new HashSet<>();
47        for (String transTocken : transTockens) {
48            if (transTocken == null || transTocken.length() == 0) {
49                continue;
50            }
51
52            // PBEWith<digest>And<encryption>
53            // PBEWith<prf>And<encryption>
54            // OAEPWith<digest>And<mgf>Padding
55            // <digest>with<encryption>
56            // <digest>with<encryption>and<mgf>
57            String[] tokens = pattern.split(transTocken);
58
59            for (String token : tokens) {
60                if (token == null || token.length() == 0) {
61                    continue;
62                }
63
64                elements.add(token);
65            }
66        }
67        return elements;
68    }
69
70    /**
71     * Decompose the standard algorithm name into sub-elements.
72     * <p>
73     * For example, we need to decompose "SHA1WithRSA" into "SHA1" and "RSA"
74     * so that we can check the "SHA1" and "RSA" algorithm constraints
75     * separately.
76     * <p>
77     * Please override the method if need to support more name pattern.
78     */
79    public Set<String> decompose(String algorithm) {
80        if (algorithm == null || algorithm.length() == 0) {
81            return new HashSet<>();
82        }
83
84        Set<String> elements = decomposeImpl(algorithm);
85
86        // In Java standard algorithm name specification, for different
87        // purpose, the SHA-1 and SHA-2 algorithm names are different. For
88        // example, for MessageDigest, the standard name is "SHA-256", while
89        // for Signature, the digest algorithm component is "SHA256" for
90        // signature algorithm "SHA256withRSA". So we need to check both
91        // "SHA-256" and "SHA256" to make the right constraint checking.
92
93        // handle special name: SHA-1 and SHA1
94        if (elements.contains("SHA1") && !elements.contains("SHA-1")) {
95            elements.add("SHA-1");
96        }
97        if (elements.contains("SHA-1") && !elements.contains("SHA1")) {
98            elements.add("SHA1");
99        }
100
101        // handle special name: SHA-224 and SHA224
102        if (elements.contains("SHA224") && !elements.contains("SHA-224")) {
103            elements.add("SHA-224");
104        }
105        if (elements.contains("SHA-224") && !elements.contains("SHA224")) {
106            elements.add("SHA224");
107        }
108
109        // handle special name: SHA-256 and SHA256
110        if (elements.contains("SHA256") && !elements.contains("SHA-256")) {
111            elements.add("SHA-256");
112        }
113        if (elements.contains("SHA-256") && !elements.contains("SHA256")) {
114            elements.add("SHA256");
115        }
116
117        // handle special name: SHA-384 and SHA384
118        if (elements.contains("SHA384") && !elements.contains("SHA-384")) {
119            elements.add("SHA-384");
120        }
121        if (elements.contains("SHA-384") && !elements.contains("SHA384")) {
122            elements.add("SHA384");
123        }
124
125        // handle special name: SHA-512 and SHA512
126        if (elements.contains("SHA512") && !elements.contains("SHA-512")) {
127            elements.add("SHA-512");
128        }
129        if (elements.contains("SHA-512") && !elements.contains("SHA512")) {
130            elements.add("SHA512");
131        }
132
133        return elements;
134    }
135
136    private static void hasLoop(Set<String> elements, String find, String replace) {
137        if (elements.contains(find)) {
138            if (!elements.contains(replace)) {
139                elements.add(replace);
140}
141            elements.remove(find);
142        }
143    }
144
145    /*
146     * This decomposes a standard name into sub-elements with a consistent
147     * message digest algorithm name to avoid overly complicated checking.
148     */
149    public static Set<String> decomposeOneHash(String algorithm) {
150        if (algorithm == null || algorithm.length() == 0) {
151            return new HashSet<>();
152        }
153
154        Set<String> elements = decomposeImpl(algorithm);
155
156        hasLoop(elements, "SHA-1", "SHA1");
157        hasLoop(elements, "SHA-224", "SHA224");
158        hasLoop(elements, "SHA-256", "SHA256");
159        hasLoop(elements, "SHA-384", "SHA384");
160        hasLoop(elements, "SHA-512", "SHA512");
161
162        return elements;
163    }
164
165    /*
166     * The provided message digest algorithm name will return a consistent
167     * naming scheme.
168     */
169    public static String hashName(String algorithm) {
170        return algorithm.replace("-", "");
171    }
172}
173