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25 
26 package sun.security.x509;
27 
28 import java.io.IOException;
29 import java.io.OutputStream;
30 import java.util.Enumeration;
31 
32 import sun.security.util.*;
33 
34 /**
35  * This class represents the Authority Key Identifier Extension.
36  *
37  * <p>The authority key identifier extension provides a means of
38  * identifying the particular public key used to sign a certificate.
39  * This extension would be used where an issuer has multiple signing
40  * keys (either due to multiple concurrent key pairs or due to
41  * changeover).
42  * <p>
43  * The ASN.1 syntax for this is:
44  * <pre>
45  * AuthorityKeyIdentifier ::= SEQUENCE {
46  *    keyIdentifier             [0] KeyIdentifier           OPTIONAL,
47  *    authorityCertIssuer       [1] GeneralNames            OPTIONAL,
48  *    authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL
49  * }
50  * KeyIdentifier ::= OCTET STRING
51  * </pre>
52  * @author Amit Kapoor
53  * @author Hemma Prafullchandra
54  * @see Extension
55  * @see CertAttrSet
56  */
57 public class AuthorityKeyIdentifierExtension extends Extension
58 implements CertAttrSet<String> {
59     /**
60      * Identifier for this attribute, to be used with the
61      * get, set, delete methods of Certificate, x509 type.
62      */
63     public static final String IDENT =
64                          "x509.info.extensions.AuthorityKeyIdentifier";
65     /**
66      * Attribute names.
67      */
68     public static final String NAME = "AuthorityKeyIdentifier";
69     public static final String KEY_ID = "key_id";
70     public static final String AUTH_NAME = "auth_name";
71     public static final String SERIAL_NUMBER = "serial_number";
72 
73     // Private data members
74     private static final byte TAG_ID = 0;
75     private static final byte TAG_NAMES = 1;
76     private static final byte TAG_SERIAL_NUM = 2;
77 
78     private KeyIdentifier       id = null;
79     private GeneralNames        names = null;
80     private SerialNumber        serialNum = null;
81 
82     // Encode only the extension value
encodeThis()83     private void encodeThis() throws IOException {
84         if (id == null && names == null && serialNum == null) {
85             this.extensionValue = null;
86             return;
87         }
88         DerOutputStream seq = new DerOutputStream();
89         DerOutputStream tmp = new DerOutputStream();
90         if (id != null) {
91             DerOutputStream tmp1 = new DerOutputStream();
92             id.encode(tmp1);
93             tmp.writeImplicit(DerValue.createTag(DerValue.TAG_CONTEXT,
94                               false, TAG_ID), tmp1);
95         }
96         try {
97             if (names != null) {
98                 DerOutputStream tmp1 = new DerOutputStream();
99                 names.encode(tmp1);
100                 tmp.writeImplicit(DerValue.createTag(DerValue.TAG_CONTEXT,
101                                   true, TAG_NAMES), tmp1);
102             }
103         } catch (Exception e) {
104             throw new IOException(e.toString());
105         }
106         if (serialNum != null) {
107             DerOutputStream tmp1 = new DerOutputStream();
108             serialNum.encode(tmp1);
109             tmp.writeImplicit(DerValue.createTag(DerValue.TAG_CONTEXT,
110                               false, TAG_SERIAL_NUM), tmp1);
111         }
112         seq.write(DerValue.tag_Sequence, tmp);
113         this.extensionValue = seq.toByteArray();
114     }
115 
116     /**
117      * The default constructor for this extension.  Null parameters make
118      * the element optional (not present).
119      *
120      * @param id the KeyIdentifier associated with this extension.
121      * @param names the GeneralNames associated with this extension
122      * @param serialNum the CertificateSerialNumber associated with
123      *         this extension.
124      * @exception IOException on error.
125      */
AuthorityKeyIdentifierExtension(KeyIdentifier kid, GeneralNames name, SerialNumber sn)126     public AuthorityKeyIdentifierExtension(KeyIdentifier kid, GeneralNames name,
127                                            SerialNumber sn)
128     throws IOException {
129         this.id = kid;
130         this.names = name;
131         this.serialNum = sn;
132 
133         this.extensionId = PKIXExtensions.AuthorityKey_Id;
134         this.critical = false;
135         encodeThis();
136     }
137 
138     /**
139      * Create the extension from the passed DER encoded value of the same.
140      *
141      * @param critical true if the extension is to be treated as critical.
142      * @param value an array of DER encoded bytes of the actual value.
143      * @exception ClassCastException if value is not an array of bytes
144      * @exception IOException on error.
145      */
AuthorityKeyIdentifierExtension(Boolean critical, Object value)146     public AuthorityKeyIdentifierExtension(Boolean critical, Object value)
147     throws IOException {
148         this.extensionId = PKIXExtensions.AuthorityKey_Id;
149         this.critical = critical.booleanValue();
150 
151         this.extensionValue = (byte[]) value;
152         DerValue val = new DerValue(this.extensionValue);
153         if (val.tag != DerValue.tag_Sequence) {
154             throw new IOException("Invalid encoding for " +
155                                   "AuthorityKeyIdentifierExtension.");
156         }
157 
158         // Note that all the fields in AuthorityKeyIdentifier are defined as
159         // being OPTIONAL, i.e., there could be an empty SEQUENCE, resulting
160         // in val.data being null.
161         while ((val.data != null) && (val.data.available() != 0)) {
162             DerValue opt = val.data.getDerValue();
163 
164             // NB. this is always encoded with the IMPLICIT tag
165             // The checks only make sense if we assume implicit tagging,
166             // with explicit tagging the form is always constructed.
167             if (opt.isContextSpecific(TAG_ID) && !opt.isConstructed()) {
168                 if (id != null)
169                     throw new IOException("Duplicate KeyIdentifier in " +
170                                           "AuthorityKeyIdentifier.");
171                 opt.resetTag(DerValue.tag_OctetString);
172                 id = new KeyIdentifier(opt);
173 
174             } else if (opt.isContextSpecific(TAG_NAMES) &&
175                        opt.isConstructed()) {
176                 if (names != null)
177                     throw new IOException("Duplicate GeneralNames in " +
178                                           "AuthorityKeyIdentifier.");
179                 opt.resetTag(DerValue.tag_Sequence);
180                 names = new GeneralNames(opt);
181 
182             } else if (opt.isContextSpecific(TAG_SERIAL_NUM) &&
183                        !opt.isConstructed()) {
184                 if (serialNum != null)
185                     throw new IOException("Duplicate SerialNumber in " +
186                                           "AuthorityKeyIdentifier.");
187                 opt.resetTag(DerValue.tag_Integer);
188                 serialNum = new SerialNumber(opt);
189             } else
190                 throw new IOException("Invalid encoding of " +
191                                       "AuthorityKeyIdentifierExtension.");
192         }
193     }
194 
195     /**
196      * Return the object as a string.
197      */
toString()198     public String toString() {
199         String s = super.toString() + "AuthorityKeyIdentifier [\n";
200         if (id != null) {
201             s += id.toString();     // id already has a newline
202         }
203         if (names != null) {
204             s += names.toString() + "\n";
205         }
206         if (serialNum != null) {
207             s += serialNum.toString() + "\n";
208         }
209         return (s + "]\n");
210     }
211 
212     /**
213      * Write the extension to the OutputStream.
214      *
215      * @param out the OutputStream to write the extension to.
216      * @exception IOException on error.
217      */
encode(OutputStream out)218     public void encode(OutputStream out) throws IOException {
219         DerOutputStream tmp = new DerOutputStream();
220         if (this.extensionValue == null) {
221             extensionId = PKIXExtensions.AuthorityKey_Id;
222             critical = false;
223             encodeThis();
224         }
225         super.encode(tmp);
226         out.write(tmp.toByteArray());
227     }
228 
229     /**
230      * Set the attribute value.
231      */
set(String name, Object obj)232     public void set(String name, Object obj) throws IOException {
233         if (name.equalsIgnoreCase(KEY_ID)) {
234             if (!(obj instanceof KeyIdentifier)) {
235               throw new IOException("Attribute value should be of " +
236                                     "type KeyIdentifier.");
237             }
238             id = (KeyIdentifier)obj;
239         } else if (name.equalsIgnoreCase(AUTH_NAME)) {
240             if (!(obj instanceof GeneralNames)) {
241               throw new IOException("Attribute value should be of " +
242                                     "type GeneralNames.");
243             }
244             names = (GeneralNames)obj;
245         } else if (name.equalsIgnoreCase(SERIAL_NUMBER)) {
246             if (!(obj instanceof SerialNumber)) {
247               throw new IOException("Attribute value should be of " +
248                                     "type SerialNumber.");
249             }
250             serialNum = (SerialNumber)obj;
251         } else {
252           throw new IOException("Attribute name not recognized by " +
253                         "CertAttrSet:AuthorityKeyIdentifier.");
254         }
255         encodeThis();
256     }
257 
258     /**
259      * Get the attribute value.
260      */
get(String name)261     public Object get(String name) throws IOException {
262         if (name.equalsIgnoreCase(KEY_ID)) {
263             return (id);
264         } else if (name.equalsIgnoreCase(AUTH_NAME)) {
265             return (names);
266         } else if (name.equalsIgnoreCase(SERIAL_NUMBER)) {
267             return (serialNum);
268         } else {
269           throw new IOException("Attribute name not recognized by " +
270                         "CertAttrSet:AuthorityKeyIdentifier.");
271         }
272     }
273 
274     /**
275      * Delete the attribute value.
276      */
delete(String name)277     public void delete(String name) throws IOException {
278         if (name.equalsIgnoreCase(KEY_ID)) {
279             id = null;
280         } else if (name.equalsIgnoreCase(AUTH_NAME)) {
281             names = null;
282         } else if (name.equalsIgnoreCase(SERIAL_NUMBER)) {
283             serialNum = null;
284         } else {
285           throw new IOException("Attribute name not recognized by " +
286                         "CertAttrSet:AuthorityKeyIdentifier.");
287         }
288         encodeThis();
289     }
290 
291     /**
292      * Return an enumeration of names of attributes existing within this
293      * attribute.
294      */
getElements()295     public Enumeration<String> getElements() {
296         AttributeNameEnumeration elements = new AttributeNameEnumeration();
297         elements.addElement(KEY_ID);
298         elements.addElement(AUTH_NAME);
299         elements.addElement(SERIAL_NUMBER);
300 
301         return (elements.elements());
302     }
303 
304     /**
305      * Return the name of this attribute.
306      */
getName()307     public String getName() {
308         return (NAME);
309     }
310 
311     /**
312      * Return the encoded key identifier, or null if not specified.
313      */
getEncodedKeyIdentifier()314     public byte[] getEncodedKeyIdentifier() throws IOException {
315         if (id != null) {
316             DerOutputStream derOut = new DerOutputStream();
317             id.encode(derOut);
318             return derOut.toByteArray();
319         }
320         return null;
321     }
322 }
323