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.security.AccessController;
29import java.security.AlgorithmConstraints;
30import java.security.PrivilegedAction;
31import java.security.Security;
32import java.util.Set;
33
34/**
35 * The class contains common functionality for algorithm constraints classes.
36 */
37public abstract class AbstractAlgorithmConstraints
38        implements AlgorithmConstraints {
39
40    protected final AlgorithmDecomposer decomposer;
41
42    protected AbstractAlgorithmConstraints(AlgorithmDecomposer decomposer) {
43        this.decomposer = decomposer;
44    }
45
46    // Get algorithm constraints from the specified security property.
47    static String[] getAlgorithms(String propertyName) {
48        String property = AccessController.doPrivileged(
49                new PrivilegedAction<String>() {
50                    @Override
51                    public String run() {
52                        return Security.getProperty(propertyName);
53                    }
54                });
55
56        String[] algorithmsInProperty = null;
57        if (property != null && !property.isEmpty()) {
58            // remove double quote marks from beginning/end of the property
59            if (property.length() >= 2 && property.charAt(0) == '"' &&
60                    property.charAt(property.length() - 1) == '"') {
61                property = property.substring(1, property.length() - 1);
62            }
63            algorithmsInProperty = property.split(",");
64            for (int i = 0; i < algorithmsInProperty.length; i++) {
65                algorithmsInProperty[i] = algorithmsInProperty[i].trim();
66            }
67        }
68
69        // map the disabled algorithms
70        if (algorithmsInProperty == null) {
71            algorithmsInProperty = new String[0];
72        }
73        return algorithmsInProperty;
74    }
75
76    static boolean checkAlgorithm(String[] algorithms, String algorithm,
77            AlgorithmDecomposer decomposer) {
78        if (algorithm == null || algorithm.length() == 0) {
79            throw new IllegalArgumentException("No algorithm name specified");
80        }
81
82        Set<String> elements = null;
83        for (String item : algorithms) {
84            if (item == null || item.isEmpty()) {
85                continue;
86            }
87
88            // check the full name
89            if (item.equalsIgnoreCase(algorithm)) {
90                return false;
91            }
92
93            // decompose the algorithm into sub-elements
94            if (elements == null) {
95                elements = decomposer.decompose(algorithm);
96            }
97
98            // check the items of the algorithm
99            for (String element : elements) {
100                if (item.equalsIgnoreCase(element)) {
101                    return false;
102                }
103            }
104        }
105
106        return true;
107    }
108
109}
110