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1   /*
2    * Copyright (c) 1997, 2011, 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
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23   * questions.
24   */
25  
26  package sun.security.x509;
27  
28  import java.io.IOException;
29  import java.util.Locale;
30  
31  import sun.security.util.*;
32  
33  /**
34   * This class implements the DNSName as required by the GeneralNames
35   * ASN.1 object.
36   * <p>
37   * [RFC2459] When the subjectAltName extension contains a domain name service
38   * label, the domain name MUST be stored in the dNSName (an IA5String).
39   * The name MUST be in the "preferred name syntax," as specified by RFC
40   * 1034 [RFC 1034]. Note that while upper and lower case letters are
41   * allowed in domain names, no signifigance is attached to the case.  In
42   * addition, while the string " " is a legal domain name, subjectAltName
43   * extensions with a dNSName " " are not permitted.  Finally, the use of
44   * the DNS representation for Internet mail addresses (wpolk.nist.gov
45   * instead of wpolk@nist.gov) is not permitted; such identities are to
46   * be encoded as rfc822Name.
47   * <p>
48   * @author Amit Kapoor
49   * @author Hemma Prafullchandra
50   */
51  public class DNSName implements GeneralNameInterface {
52      private String name;
53  
54      private static final String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
55      private static final String digitsAndHyphen = "0123456789-";
56      private static final String alphaDigitsAndHyphen = alpha + digitsAndHyphen;
57  
58      /**
59       * Create the DNSName object from the passed encoded Der value.
60       *
61       * @param derValue the encoded DER DNSName.
62       * @exception IOException on error.
63       */
64      public DNSName(DerValue derValue) throws IOException {
65          name = derValue.getIA5String();
66      }
67  
68      /**
69       * Create the DNSName object with the specified name.
70       *
71       * @param name the DNSName.
72       * @throws IOException if the name is not a valid DNSName subjectAltName
73       */
74      public DNSName(String name) throws IOException {
75          if (name == null || name.length() == 0)
76              throw new IOException("DNS name must not be null");
77          if (name.indexOf(' ') != -1)
78              throw new IOException("DNS names or NameConstraints with blank components are not permitted");
79          if (name.charAt(0) == '.' || name.charAt(name.length() -1) == '.')
80              throw new IOException("DNS names or NameConstraints may not begin or end with a .");
81          //Name will consist of label components separated by "."
82          //startIndex is the index of the first character of a component
83          //endIndex is the index of the last character of a component plus 1
84          for (int endIndex,startIndex=0; startIndex < name.length(); startIndex = endIndex+1) {
85              endIndex = name.indexOf('.', startIndex);
86              if (endIndex < 0) {
87                  endIndex = name.length();
88              }
89              if ((endIndex-startIndex) < 1)
90                  throw new IOException("DNSName SubjectAltNames with empty components are not permitted");
91  
92              //DNSName components must begin with a letter A-Z or a-z
93              if (alpha.indexOf(name.charAt(startIndex)) < 0)
94                  throw new IOException("DNSName components must begin with a letter");
95              //nonStartIndex: index for characters in the component beyond the first one
96              for (int nonStartIndex=startIndex+1; nonStartIndex < endIndex; nonStartIndex++) {
97                  char x = name.charAt(nonStartIndex);
98                  if ((alphaDigitsAndHyphen).indexOf(x) < 0)
99                      throw new IOException("DNSName components must consist of letters, digits, and hyphens");
100             }
101         }
102         this.name = name;
103     }
104 
105     /**
106      * Return the type of the GeneralName.
107      */
108     public int getType() {
109         return (GeneralNameInterface.NAME_DNS);
110     }
111 
112     /**
113      * Return the actual name value of the GeneralName.
114      */
115     public String getName() {
116         return name;
117     }
118 
119     /**
120      * Encode the DNS name into the DerOutputStream.
121      *
122      * @param out the DER stream to encode the DNSName to.
123      * @exception IOException on encoding errors.
124      */
125     public void encode(DerOutputStream out) throws IOException {
126         out.putIA5String(name);
127     }
128 
129     /**
130      * Convert the name into user readable string.
131      */
132     public String toString() {
133         return ("DNSName: " + name);
134     }
135 
136     /**
137      * Compares this name with another, for equality.
138      *
139      * @return true iff the names are equivalent
140      * according to RFC2459.
141      */
142     public boolean equals(Object obj) {
143         if (this == obj)
144             return true;
145 
146         if (!(obj instanceof DNSName))
147             return false;
148 
149         DNSName other = (DNSName)obj;
150 
151         // RFC2459 mandates that these names are
152         // not case-sensitive
153         return name.equalsIgnoreCase(other.name);
154     }
155 
156     /**
157      * Returns the hash code value for this object.
158      *
159      * @return a hash code value for this object.
160      */
161     public int hashCode() {
162         return name.toUpperCase(Locale.ENGLISH).hashCode();
163     }
164 
165     /**
166      * Return type of constraint inputName places on this name:<ul>
167      *   <li>NAME_DIFF_TYPE = -1: input name is different type from name (i.e. does not constrain).
168      *   <li>NAME_MATCH = 0: input name matches name.
169      *   <li>NAME_NARROWS = 1: input name narrows name (is lower in the naming subtree)
170      *   <li>NAME_WIDENS = 2: input name widens name (is higher in the naming subtree)
171      *   <li>NAME_SAME_TYPE = 3: input name does not match or narrow name, but is same type.
172      * </ul>.  These results are used in checking NameConstraints during
173      * certification path verification.
174      * <p>
175      * RFC2459: DNS name restrictions are expressed as foo.bar.com. Any subdomain
176      * satisfies the name constraint. For example, www.foo.bar.com would
177      * satisfy the constraint but bigfoo.bar.com would not.
178      * <p>
179      * draft-ietf-pkix-new-part1-00.txt:  DNS name restrictions are expressed as foo.bar.com.
180      * Any DNS name that
181      * can be constructed by simply adding to the left hand side of the name
182      * satisfies the name constraint. For example, www.foo.bar.com would
183      * satisfy the constraint but foo1.bar.com would not.
184      * <p>
185      * RFC1034: By convention, domain names can be stored with arbitrary case, but
186      * domain name comparisons for all present domain functions are done in a
187      * case-insensitive manner, assuming an ASCII character set, and a high
188      * order zero bit.
189      * <p>
190      * @param inputName to be checked for being constrained
191      * @returns constraint type above
192      * @throws UnsupportedOperationException if name is not exact match, but narrowing and widening are
193      *          not supported for this name type.
194      */
195     public int constrains(GeneralNameInterface inputName) throws UnsupportedOperationException {
196         int constraintType;
197         if (inputName == null)
198             constraintType = NAME_DIFF_TYPE;
199         else if (inputName.getType() != NAME_DNS)
200             constraintType = NAME_DIFF_TYPE;
201         else {
202             String inName =
203                 (((DNSName)inputName).getName()).toLowerCase(Locale.ENGLISH);
204             String thisName = name.toLowerCase(Locale.ENGLISH);
205             if (inName.equals(thisName))
206                 constraintType = NAME_MATCH;
207             else if (thisName.endsWith(inName)) {
208                 int inNdx = thisName.lastIndexOf(inName);
209                 if (thisName.charAt(inNdx-1) == '.' )
210                     constraintType = NAME_WIDENS;
211                 else
212                     constraintType = NAME_SAME_TYPE;
213             } else if (inName.endsWith(thisName)) {
214                 int ndx = inName.lastIndexOf(thisName);
215                 if (inName.charAt(ndx-1) == '.' )
216                     constraintType = NAME_NARROWS;
217                 else
218                     constraintType = NAME_SAME_TYPE;
219             } else {
220                 constraintType = NAME_SAME_TYPE;
221             }
222         }
223         return constraintType;
224     }
225 
226     /**
227      * Return subtree depth of this name for purposes of determining
228      * NameConstraints minimum and maximum bounds and for calculating
229      * path lengths in name subtrees.
230      *
231      * @returns distance of name from root
232      * @throws UnsupportedOperationException if not supported for this name type
233      */
234     public int subtreeDepth() throws UnsupportedOperationException {
235         String subtree=name;
236         int i=1;
237 
238         /* count dots */
239         for (; subtree.lastIndexOf('.') >= 0; i++) {
240             subtree=subtree.substring(0,subtree.lastIndexOf('.'));
241         }
242 
243         return i;
244     }
245 
246 }