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25 
26 package java.security.cert;
27 
28 import java.security.AccessController;
29 import java.security.InvalidAlgorithmParameterException;
30 import java.security.NoSuchAlgorithmException;
31 import java.security.NoSuchProviderException;
32 import java.security.PrivilegedAction;
33 import java.security.Provider;
34 import java.security.Security;
35 import sun.security.util.Debug;
36 
37 import sun.security.jca.*;
38 import sun.security.jca.GetInstance.Instance;
39 
40 /**
41  * A class for validating certification paths (also known as certificate
42  * chains).
43  * <p>
44  * This class uses a provider-based architecture.
45  * To create a {@code CertPathValidator},
46  * call one of the static {@code getInstance} methods, passing in the
47  * algorithm name of the {@code CertPathValidator} desired and
48  * optionally the name of the provider desired.
49  *
50  * <p>Once a {@code CertPathValidator} object has been created, it can
51  * be used to validate certification paths by calling the {@link #validate
52  * validate} method and passing it the {@code CertPath} to be validated
53  * and an algorithm-specific set of parameters. If successful, the result is
54  * returned in an object that implements the
55  * {@code CertPathValidatorResult} interface.
56  *
57  * <p>The {@link #getRevocationChecker} method allows an application to specify
58  * additional algorithm-specific parameters and options used by the
59  * {@code CertPathValidator} when checking the revocation status of
60  * certificates. Here is an example demonstrating how it is used with the PKIX
61  * algorithm:
62  *
63  * <pre>
64  * CertPathValidator cpv = CertPathValidator.getInstance("PKIX");
65  * PKIXRevocationChecker rc = (PKIXRevocationChecker)cpv.getRevocationChecker();
66  * rc.setOptions(EnumSet.of(Option.SOFT_FAIL));
67  * params.addCertPathChecker(rc);
68  * CertPathValidatorResult cpvr = cpv.validate(path, params);
69  * </pre>
70  *
71  * <p> Android provides the following {@code CertPathValidator} algorithms:
72  * <table>
73  *   <thead>
74  *     <tr>
75  *       <th>Algorithm</th>
76  *       <th>Supported API Levels</th>
77  *     </tr>
78  *   </thead>
79  *   <tbody>
80  *     <tr>
81  *       <td>PKIX</td>
82  *       <td>1+</td>
83  *     </tr>
84  *   </tbody>
85  * </table>
86  *
87  * This algorithm is described in the <a href=
88  * "{@docRoot}/../technotes/guides/security/StandardNames.html#CertPathValidator">
89  * CertPathValidator section</a> of the
90  * Java Cryptography Architecture Standard Algorithm Name Documentation.
91  *
92  * <p>
93  * <b>Concurrent Access</b>
94  * <p>
95  * The static methods of this class are guaranteed to be thread-safe.
96  * Multiple threads may concurrently invoke the static methods defined in
97  * this class with no ill effects.
98  * <p>
99  * However, this is not true for the non-static methods defined by this class.
100  * Unless otherwise documented by a specific provider, threads that need to
101  * access a single {@code CertPathValidator} instance concurrently should
102  * synchronize amongst themselves and provide the necessary locking. Multiple
103  * threads each manipulating a different {@code CertPathValidator}
104  * instance need not synchronize.
105  *
106  * @see CertPath
107  *
108  * @since       1.4
109  * @author      Yassir Elley
110  */
111 public class CertPathValidator {
112 
113     /*
114      * Constant to lookup in the Security properties file to determine
115      * the default certpathvalidator type. In the Security properties file,
116      * the default certpathvalidator type is given as:
117      * <pre>
118      * certpathvalidator.type=PKIX
119      * </pre>
120      */
121     private static final String CPV_TYPE = "certpathvalidator.type";
122     private final CertPathValidatorSpi validatorSpi;
123     private final Provider provider;
124     private final String algorithm;
125 
126     /**
127      * Creates a {@code CertPathValidator} object of the given algorithm,
128      * and encapsulates the given provider implementation (SPI object) in it.
129      *
130      * @param validatorSpi the provider implementation
131      * @param provider the provider
132      * @param algorithm the algorithm name
133      */
CertPathValidator(CertPathValidatorSpi validatorSpi, Provider provider, String algorithm)134     protected CertPathValidator(CertPathValidatorSpi validatorSpi,
135         Provider provider, String algorithm)
136     {
137         this.validatorSpi = validatorSpi;
138         this.provider = provider;
139         this.algorithm = algorithm;
140     }
141 
142     /**
143      * Returns a {@code CertPathValidator} object that implements the
144      * specified algorithm.
145      *
146      * <p> This method traverses the list of registered security Providers,
147      * starting with the most preferred Provider.
148      * A new CertPathValidator object encapsulating the
149      * CertPathValidatorSpi implementation from the first
150      * Provider that supports the specified algorithm is returned.
151      *
152      * <p> Note that the list of registered providers may be retrieved via
153      * the {@link Security#getProviders() Security.getProviders()} method.
154      *
155      * @param algorithm the name of the requested {@code CertPathValidator}
156      *  algorithm. See the CertPathValidator section in the <a href=
157      *  "{@docRoot}/../technotes/guides/security/StandardNames.html#CertPathValidator">
158      * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
159      * for information about standard algorithm names.
160      *
161      * @return a {@code CertPathValidator} object that implements the
162      *          specified algorithm.
163      *
164      * @exception NoSuchAlgorithmException if no Provider supports a
165      *          CertPathValidatorSpi implementation for the
166      *          specified algorithm.
167      *
168      * @see java.security.Provider
169      */
getInstance(String algorithm)170     public static CertPathValidator getInstance(String algorithm)
171             throws NoSuchAlgorithmException {
172         Instance instance = GetInstance.getInstance("CertPathValidator",
173             CertPathValidatorSpi.class, algorithm);
174         return new CertPathValidator((CertPathValidatorSpi)instance.impl,
175             instance.provider, algorithm);
176     }
177 
178     /**
179      * Returns a {@code CertPathValidator} object that implements the
180      * specified algorithm.
181      *
182      * <p> A new CertPathValidator object encapsulating the
183      * CertPathValidatorSpi implementation from the specified provider
184      * is returned.  The specified provider must be registered
185      * in the security provider list.
186      *
187      * <p> Note that the list of registered providers may be retrieved via
188      * the {@link Security#getProviders() Security.getProviders()} method.
189      *
190      * @param algorithm the name of the requested {@code CertPathValidator}
191      *  algorithm. See the CertPathValidator section in the <a href=
192      *  "{@docRoot}/../technotes/guides/security/StandardNames.html#CertPathValidator">
193      * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
194      * for information about standard algorithm names.
195      *
196      * @param provider the name of the provider.
197      *
198      * @return a {@code CertPathValidator} object that implements the
199      *          specified algorithm.
200      *
201      * @exception NoSuchAlgorithmException if a CertPathValidatorSpi
202      *          implementation for the specified algorithm is not
203      *          available from the specified provider.
204      *
205      * @exception NoSuchProviderException if the specified provider is not
206      *          registered in the security provider list.
207      *
208      * @exception IllegalArgumentException if the {@code provider} is
209      *          null or empty.
210      *
211      * @see java.security.Provider
212      */
getInstance(String algorithm, String provider)213     public static CertPathValidator getInstance(String algorithm,
214             String provider) throws NoSuchAlgorithmException,
215             NoSuchProviderException {
216         Instance instance = GetInstance.getInstance("CertPathValidator",
217             CertPathValidatorSpi.class, algorithm, provider);
218         return new CertPathValidator((CertPathValidatorSpi)instance.impl,
219             instance.provider, algorithm);
220     }
221 
222     /**
223      * Returns a {@code CertPathValidator} object that implements the
224      * specified algorithm.
225      *
226      * <p> A new CertPathValidator object encapsulating the
227      * CertPathValidatorSpi implementation from the specified Provider
228      * object is returned.  Note that the specified Provider object
229      * does not have to be registered in the provider list.
230      *
231      * @param algorithm the name of the requested {@code CertPathValidator}
232      * algorithm. See the CertPathValidator section in the <a href=
233      * "{@docRoot}/../technotes/guides/security/StandardNames.html#CertPathValidator">
234      * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
235      * for information about standard algorithm names.
236      *
237      * @param provider the provider.
238      *
239      * @return a {@code CertPathValidator} object that implements the
240      *          specified algorithm.
241      *
242      * @exception NoSuchAlgorithmException if a CertPathValidatorSpi
243      *          implementation for the specified algorithm is not available
244      *          from the specified Provider object.
245      *
246      * @exception IllegalArgumentException if the {@code provider} is
247      *          null.
248      *
249      * @see java.security.Provider
250      */
getInstance(String algorithm, Provider provider)251     public static CertPathValidator getInstance(String algorithm,
252             Provider provider) throws NoSuchAlgorithmException {
253         Instance instance = GetInstance.getInstance("CertPathValidator",
254             CertPathValidatorSpi.class, algorithm, provider);
255         return new CertPathValidator((CertPathValidatorSpi)instance.impl,
256             instance.provider, algorithm);
257     }
258 
259     /**
260      * Returns the {@code Provider} of this
261      * {@code CertPathValidator}.
262      *
263      * @return the {@code Provider} of this {@code CertPathValidator}
264      */
getProvider()265     public final Provider getProvider() {
266         return this.provider;
267     }
268 
269     /**
270      * Returns the algorithm name of this {@code CertPathValidator}.
271      *
272      * @return the algorithm name of this {@code CertPathValidator}
273      */
getAlgorithm()274     public final String getAlgorithm() {
275         return this.algorithm;
276     }
277 
278     /**
279      * Validates the specified certification path using the specified
280      * algorithm parameter set.
281      * <p>
282      * The {@code CertPath} specified must be of a type that is
283      * supported by the validation algorithm, otherwise an
284      * {@code InvalidAlgorithmParameterException} will be thrown. For
285      * example, a {@code CertPathValidator} that implements the PKIX
286      * algorithm validates {@code CertPath} objects of type X.509.
287      *
288      * @param certPath the {@code CertPath} to be validated
289      * @param params the algorithm parameters
290      * @return the result of the validation algorithm
291      * @exception CertPathValidatorException if the {@code CertPath}
292      * does not validate
293      * @exception InvalidAlgorithmParameterException if the specified
294      * parameters or the type of the specified {@code CertPath} are
295      * inappropriate for this {@code CertPathValidator}
296      */
validate(CertPath certPath, CertPathParameters params)297     public final CertPathValidatorResult validate(CertPath certPath,
298         CertPathParameters params)
299         throws CertPathValidatorException, InvalidAlgorithmParameterException
300     {
301         return validatorSpi.engineValidate(certPath, params);
302     }
303 
304     /**
305      * Returns the default {@code CertPathValidator} type as specified by
306      * the {@code certpathvalidator.type} security property, or the string
307      * {@literal "PKIX"} if no such property exists.
308      *
309      * <p>The default {@code CertPathValidator} type can be used by
310      * applications that do not want to use a hard-coded type when calling one
311      * of the {@code getInstance} methods, and want to provide a default
312      * type in case a user does not specify its own.
313      *
314      * <p>The default {@code CertPathValidator} type can be changed by
315      * setting the value of the {@code certpathvalidator.type} security
316      * property to the desired type.
317      *
318      * @see java.security.Security security properties
319      * @return the default {@code CertPathValidator} type as specified
320      * by the {@code certpathvalidator.type} security property, or the string
321      * {@literal "PKIX"} if no such property exists.
322      */
getDefaultType()323     public final static String getDefaultType() {
324         String cpvtype =
325             AccessController.doPrivileged(new PrivilegedAction<String>() {
326                 public String run() {
327                     return Security.getProperty(CPV_TYPE);
328                 }
329             });
330         return (cpvtype == null) ? "PKIX" : cpvtype;
331     }
332 
333     /**
334      * Returns a {@code CertPathChecker} that the encapsulated
335      * {@code CertPathValidatorSpi} implementation uses to check the revocation
336      * status of certificates. A PKIX implementation returns objects of
337      * type {@code PKIXRevocationChecker}. Each invocation of this method
338      * returns a new instance of {@code CertPathChecker}.
339      *
340      * <p>The primary purpose of this method is to allow callers to specify
341      * additional input parameters and options specific to revocation checking.
342      * See the class description for an example.
343      *
344      * @return a {@code CertPathChecker}
345      * @throws UnsupportedOperationException if the service provider does not
346      *         support this method
347      * @since 1.8
348      */
getRevocationChecker()349     public final CertPathChecker getRevocationChecker() {
350         return validatorSpi.engineGetRevocationChecker();
351     }
352 }
353