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      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 
     26 package sun.security.util;
     27 
     28 import java.util.HashSet;
     29 import java.util.Set;
     30 import java.util.regex.Pattern;
     31 
     32 /**
     33  * The class decomposes standard algorithms into sub-elements.
     34  */
     35 public 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