1 /*
2 * Copyright (c) 1997, 2015, 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
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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
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20 *
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23 * questions.
24 */
25
26
27 package java.security;
28
29 import java.util.Enumeration;
30 import java.util.WeakHashMap;
31 import java.util.concurrent.atomic.AtomicReference;
32 import sun.security.jca.GetInstance;
33 import sun.security.util.Debug;
34 import sun.security.util.SecurityConstants;
35
36
37 /**
38 * A Policy object is responsible for determining whether code executing
39 * in the Java runtime environment has permission to perform a
40 * security-sensitive operation.
41 *
42 * <p> There is only one Policy object installed in the runtime at any
43 * given time. A Policy object can be installed by calling the
44 * {@code setPolicy} method. The installed Policy object can be
45 * obtained by calling the {@code getPolicy} method.
46 *
47 * <p> If no Policy object has been installed in the runtime, a call to
48 * {@code getPolicy} installs an instance of the default Policy
49 * implementation (a default subclass implementation of this abstract class).
50 * The default Policy implementation can be changed by setting the value
51 * of the {@code policy.provider} security property to the fully qualified
52 * name of the desired Policy subclass implementation. The system class loader
53 * is used to load this class.
54 *
55 * <p> Application code can directly subclass Policy to provide a custom
56 * implementation. In addition, an instance of a Policy object can be
57 * constructed by invoking one of the {@code getInstance} factory methods
58 * with a standard type. The default policy type is "JavaPolicy".
59 *
60 * <p> Once a Policy instance has been installed (either by default, or by
61 * calling {@code setPolicy}), the Java runtime invokes its
62 * {@code implies} method when it needs to
63 * determine whether executing code (encapsulated in a ProtectionDomain)
64 * can perform SecurityManager-protected operations. How a Policy object
65 * retrieves its policy data is up to the Policy implementation itself.
66 * The policy data may be stored, for example, in a flat ASCII file,
67 * in a serialized binary file of the Policy class, or in a database.
68 *
69 * <p> The {@code refresh} method causes the policy object to
70 * refresh/reload its data. This operation is implementation-dependent.
71 * For example, if the policy object stores its data in configuration files,
72 * calling {@code refresh} will cause it to re-read the configuration
73 * policy files. If a refresh operation is not supported, this method does
74 * nothing. Note that refreshed policy may not have an effect on classes
75 * in a particular ProtectionDomain. This is dependent on the Policy
76 * provider's implementation of the {@code implies}
77 * method and its PermissionCollection caching strategy.
78 *
79 * @author Roland Schemers
80 * @author Gary Ellison
81 * @see java.security.Provider
82 * @see java.security.ProtectionDomain
83 * @see java.security.Permission
84 * @see java.security.Security security properties
85 */
86
87 public abstract class Policy {
88
89 /**
90 * A read-only empty PermissionCollection instance.
91 * @since 1.6
92 */
93 public static final PermissionCollection UNSUPPORTED_EMPTY_COLLECTION =
94 new UnsupportedEmptyCollection();
95
96 // Information about the system-wide policy.
97 private static class PolicyInfo {
98 // the system-wide policy
99 final Policy policy;
100 // a flag indicating if the system-wide policy has been initialized
101 final boolean initialized;
102
103 PolicyInfo(Policy policy, boolean initialized) {
104 this.policy = policy;
105 this.initialized = initialized;
106 }
107 }
108
109 // PolicyInfo is stored in an AtomicReference
110 private static AtomicReference<PolicyInfo> policy =
111 new AtomicReference<>(new PolicyInfo(null, false));
112
113 private static final Debug debug = Debug.getInstance("policy");
114
115 // Default policy provider
116 private static final String DEFAULT_POLICY =
117 "sun.security.provider.PolicyFile";
118
119 // Cache mapping ProtectionDomain.Key to PermissionCollection
120 private WeakHashMap<ProtectionDomain.Key, PermissionCollection> pdMapping;
121
122 /** package private for AccessControlContext and ProtectionDomain */
123 static boolean isSet()
124 {
125 PolicyInfo pi = policy.get();
126 return pi.policy != null && pi.initialized == true;
127 }
128
129 private static void checkPermission(String type) {
130 SecurityManager sm = System.getSecurityManager();
131 if (sm != null) {
132 sm.checkPermission(new SecurityPermission("createPolicy." + type));
133 }
134 }
135
136 /**
137 * Returns the installed Policy object. This value should not be cached,
138 * as it may be changed by a call to {@code setPolicy}.
139 * This method first calls
140 * {@code SecurityManager.checkPermission} with a
141 * {@code SecurityPermission("getPolicy")} permission
142 * to ensure it's ok to get the Policy object.
143 *
144 * @return the installed Policy.
145 *
146 * @throws SecurityException
147 * if a security manager exists and its
148 * {@code checkPermission} method doesn't allow
149 * getting the Policy object.
150 *
151 * @see SecurityManager#checkPermission(Permission)
152 * @see #setPolicy(java.security.Policy)
153 */
154 public static Policy getPolicy()
155 {
156 SecurityManager sm = System.getSecurityManager();
157 if (sm != null)
158 sm.checkPermission(SecurityConstants.GET_POLICY_PERMISSION);
159 return getPolicyNoCheck();
160 }
161
162 /**
163 * Returns the installed Policy object, skipping the security check.
164 * Used by ProtectionDomain and getPolicy.
165 *
166 * @return the installed Policy.
167 */
168 static Policy getPolicyNoCheck()
169 {
170 PolicyInfo pi = policy.get();
171 // Use double-check idiom to avoid locking if system-wide policy is
172 // already initialized
173 if (pi.initialized == false || pi.policy == null) {
174 synchronized (Policy.class) {
175 PolicyInfo pinfo = policy.get();
176 if (pinfo.policy == null) {
177 return loadPolicyProvider();
178 }
179 return pinfo.policy;
180 }
181 }
182 return pi.policy;
183 }
184
185 /**
186 * Loads and instantiates a Policy implementation specified by the
187 * policy.provider security property. Note that this method should only
188 * be called by getPolicyNoCheck and from within a synchronized block with
189 * an intrinsic lock on the Policy.class.
190 */
191 private static Policy loadPolicyProvider() {
192 String policyProvider =
193 AccessController.doPrivileged(new PrivilegedAction<>() {
194 @Override
195 public String run() {
196 return Security.getProperty("policy.provider");
197 }
198 });
199
200 /*
201 * If policy.provider is not set or is set to the default provider,
202 * simply instantiate it and return.
203 */
204 if (policyProvider == null || policyProvider.isEmpty() ||
205 policyProvider.equals(DEFAULT_POLICY))
206 {
207 Policy polFile = new sun.security.provider.PolicyFile();
208 policy.set(new PolicyInfo(polFile, true));
209 return polFile;
210 }
211
212 /*
213 * Locate, load, and instantiate the policy.provider impl using
214 * the system class loader. While doing so, install the bootstrap
215 * provider to avoid potential recursion.
216 */
217 Policy polFile = new sun.security.provider.PolicyFile();
218 policy.set(new PolicyInfo(polFile, false));
219
220 Policy pol = AccessController.doPrivileged(new PrivilegedAction<>() {
221 @Override
222 public Policy run() {
223 try {
224 ClassLoader scl = ClassLoader.getSystemClassLoader();
225 Class<?> c = Class.forName(policyProvider, true, scl);
226 return (Policy)c.newInstance();
227 } catch (Exception e) {
228 if (debug != null) {
229 debug.println("policy provider " + policyProvider +
230 " not available");
231 e.printStackTrace();
232 }
233 return null;
234 }
235 }
236 });
237
238 if (pol == null) {
239 // Fallback and use the system default implementation
240 if (debug != null) {
241 debug.println("using " + DEFAULT_POLICY);
242 }
243 pol = polFile;
244 }
245 policy.set(new PolicyInfo(pol, true));
246 return pol;
247 }
248
249 /**
250 * Sets the system-wide Policy object. This method first calls
251 * {@code SecurityManager.checkPermission} with a
252 * {@code SecurityPermission("setPolicy")}
253 * permission to ensure it's ok to set the Policy.
254 *
255 * @param p the new system Policy object.
256 *
257 * @throws SecurityException
258 * if a security manager exists and its
259 * {@code checkPermission} method doesn't allow
260 * setting the Policy.
261 *
262 * @see SecurityManager#checkPermission(Permission)
263 * @see #getPolicy()
264 *
265 */
266 public static void setPolicy(Policy p)
267 {
268 SecurityManager sm = System.getSecurityManager();
269 if (sm != null) sm.checkPermission(
270 new SecurityPermission("setPolicy"));
271 if (p != null) {
272 initPolicy(p);
273 }
274 synchronized (Policy.class) {
275 policy.set(new PolicyInfo(p, p != null));
276 }
277 }
278
279 /**
280 * Initialize superclass state such that a legacy provider can
281 * handle queries for itself.
282 *
283 * @since 1.4
284 */
285 private static void initPolicy (final Policy p) {
286 /*
287 * A policy provider not on the bootclasspath could trigger
288 * security checks fulfilling a call to either Policy.implies
289 * or Policy.getPermissions. If this does occur the provider
290 * must be able to answer for it's own ProtectionDomain
291 * without triggering additional security checks, otherwise
292 * the policy implementation will end up in an infinite
293 * recursion.
294 *
295 * To mitigate this, the provider can collect it's own
296 * ProtectionDomain and associate a PermissionCollection while
297 * it is being installed. The currently installed policy
298 * provider (if there is one) will handle calls to
299 * Policy.implies or Policy.getPermissions during this
300 * process.
301 *
302 * This Policy superclass caches away the ProtectionDomain and
303 * statically binds permissions so that legacy Policy
304 * implementations will continue to function.
305 */
306
307 ProtectionDomain policyDomain =
308 AccessController.doPrivileged(new PrivilegedAction<>() {
309 public ProtectionDomain run() {
310 return p.getClass().getProtectionDomain();
311 }
312 });
313
314 /*
315 * Collect the permissions granted to this protection domain
316 * so that the provider can be security checked while processing
317 * calls to Policy.implies or Policy.getPermissions.
318 */
319 PermissionCollection policyPerms = null;
320 synchronized (p) {
321 if (p.pdMapping == null) {
322 p.pdMapping = new WeakHashMap<>();
323 }
324 }
325
326 if (policyDomain.getCodeSource() != null) {
327 Policy pol = policy.get().policy;
328 if (pol != null) {
329 policyPerms = pol.getPermissions(policyDomain);
330 }
331
332 if (policyPerms == null) { // assume it has all
333 policyPerms = new Permissions();
334 policyPerms.add(SecurityConstants.ALL_PERMISSION);
335 }
336
337 synchronized (p.pdMapping) {
338 // cache of pd to permissions
339 p.pdMapping.put(policyDomain.key, policyPerms);
340 }
341 }
342 return;
343 }
344
345
346 /**
347 * Returns a Policy object of the specified type.
348 *
349 * <p> This method traverses the list of registered security providers,
350 * starting with the most preferred Provider.
351 * A new Policy object encapsulating the
352 * PolicySpi implementation from the first
353 * Provider that supports the specified type is returned.
354 *
355 * <p> Note that the list of registered providers may be retrieved via
356 * the {@link Security#getProviders() Security.getProviders()} method.
357 *
358 * @implNote
359 * The JDK Reference Implementation additionally uses the
360 * {@code jdk.security.provider.preferred} property to determine
361 * the preferred provider order for the specified algorithm. This
362 * may be different than the order of providers returned by
363 * {@link Security#getProviders() Security.getProviders()}.
364 *
365 * @param type the specified Policy type. See the Policy section in the
366 * <a href=
367 * "{@docRoot}/../technotes/guides/security/StandardNames.html#Policy">
368 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
369 * for a list of standard Policy types.
370 *
371 * @param params parameters for the Policy, which may be null.
372 *
373 * @return the new Policy object.
374 *
375 * @exception SecurityException if the caller does not have permission
376 * to get a Policy instance for the specified type.
377 *
378 * @exception NullPointerException if the specified type is null.
379 *
380 * @exception IllegalArgumentException if the specified parameters
381 * are not understood by the PolicySpi implementation
382 * from the selected Provider.
383 *
384 * @exception NoSuchAlgorithmException if no Provider supports a PolicySpi
385 * implementation for the specified type.
386 *
387 * @see Provider
388 * @since 1.6
389 */
390 public static Policy getInstance(String type, Policy.Parameters params)
391 throws NoSuchAlgorithmException {
392
393 checkPermission(type);
394 try {
395 GetInstance.Instance instance = GetInstance.getInstance("Policy",
396 PolicySpi.class,
397 type,
398 params);
399 return new PolicyDelegate((PolicySpi)instance.impl,
400 instance.provider,
401 type,
402 params);
403 } catch (NoSuchAlgorithmException nsae) {
404 return handleException(nsae);
405 }
406 }
407
408 /**
409 * Returns a Policy object of the specified type.
410 *
411 * <p> A new Policy object encapsulating the
412 * PolicySpi implementation from the specified provider
413 * is returned. The specified provider must be registered
414 * in the provider list.
415 *
416 * <p> Note that the list of registered providers may be retrieved via
417 * the {@link Security#getProviders() Security.getProviders()} method.
418 *
419 * @param type the specified Policy type. See the Policy section in the
420 * <a href=
421 * "{@docRoot}/../technotes/guides/security/StandardNames.html#Policy">
422 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
423 * for a list of standard Policy types.
424 *
425 * @param params parameters for the Policy, which may be null.
426 *
427 * @param provider the provider.
428 *
429 * @return the new Policy object.
430 *
431 * @exception SecurityException if the caller does not have permission
432 * to get a Policy instance for the specified type.
433 *
434 * @exception NullPointerException if the specified type is null.
435 *
436 * @exception IllegalArgumentException if the specified provider
437 * is null or empty,
438 * or if the specified parameters are not understood by
439 * the PolicySpi implementation from the specified provider.
440 *
441 * @exception NoSuchProviderException if the specified provider is not
442 * registered in the security provider list.
443 *
444 * @exception NoSuchAlgorithmException if the specified provider does not
445 * support a PolicySpi implementation for the specified type.
446 *
447 * @see Provider
448 * @since 1.6
449 */
450 public static Policy getInstance(String type,
451 Policy.Parameters params,
452 String provider)
453 throws NoSuchProviderException, NoSuchAlgorithmException {
454
455 if (provider == null || provider.length() == 0) {
456 throw new IllegalArgumentException("missing provider");
457 }
458
459 checkPermission(type);
460 try {
461 GetInstance.Instance instance = GetInstance.getInstance("Policy",
462 PolicySpi.class,
463 type,
464 params,
465 provider);
466 return new PolicyDelegate((PolicySpi)instance.impl,
467 instance.provider,
468 type,
469 params);
470 } catch (NoSuchAlgorithmException nsae) {
471 return handleException(nsae);
472 }
473 }
474
475 /**
476 * Returns a Policy object of the specified type.
477 *
478 * <p> A new Policy object encapsulating the
479 * PolicySpi implementation from the specified Provider
480 * object is returned. Note that the specified Provider object
481 * does not have to be registered in the provider list.
482 *
483 * @param type the specified Policy type. See the Policy section in the
484 * <a href=
485 * "{@docRoot}/../technotes/guides/security/StandardNames.html#Policy">
486 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
487 * for a list of standard Policy types.
488 *
489 * @param params parameters for the Policy, which may be null.
490 *
491 * @param provider the Provider.
492 *
493 * @return the new Policy object.
494 *
495 * @exception SecurityException if the caller does not have permission
496 * to get a Policy instance for the specified type.
497 *
498 * @exception NullPointerException if the specified type is null.
499 *
500 * @exception IllegalArgumentException if the specified Provider is null,
501 * or if the specified parameters are not understood by
502 * the PolicySpi implementation from the specified Provider.
503 *
504 * @exception NoSuchAlgorithmException if the specified Provider does not
505 * support a PolicySpi implementation for the specified type.
506 *
507 * @see Provider
508 * @since 1.6
509 */
510 public static Policy getInstance(String type,
511 Policy.Parameters params,
512 Provider provider)
513 throws NoSuchAlgorithmException {
514
515 if (provider == null) {
516 throw new IllegalArgumentException("missing provider");
517 }
518
519 checkPermission(type);
520 try {
521 GetInstance.Instance instance = GetInstance.getInstance("Policy",
522 PolicySpi.class,
523 type,
524 params,
525 provider);
526 return new PolicyDelegate((PolicySpi)instance.impl,
527 instance.provider,
528 type,
529 params);
530 } catch (NoSuchAlgorithmException nsae) {
531 return handleException(nsae);
532 }
533 }
534
535 private static Policy handleException(NoSuchAlgorithmException nsae)
536 throws NoSuchAlgorithmException {
537 Throwable cause = nsae.getCause();
538 if (cause instanceof IllegalArgumentException) {
539 throw (IllegalArgumentException)cause;
540 }
541 throw nsae;
542 }
543
544 /**
545 * Return the Provider of this Policy.
546 *
547 * <p> This Policy instance will only have a Provider if it
548 * was obtained via a call to {@code Policy.getInstance}.
549 * Otherwise this method returns null.
550 *
551 * @return the Provider of this Policy, or null.
552 *
553 * @since 1.6
554 */
555 public Provider getProvider() {
556 return null;
557 }
558
559 /**
560 * Return the type of this Policy.
561 *
562 * <p> This Policy instance will only have a type if it
563 * was obtained via a call to {@code Policy.getInstance}.
564 * Otherwise this method returns null.
565 *
566 * @return the type of this Policy, or null.
567 *
568 * @since 1.6
569 */
570 public String getType() {
571 return null;
572 }
573
574 /**
575 * Return Policy parameters.
576 *
577 * <p> This Policy instance will only have parameters if it
578 * was obtained via a call to {@code Policy.getInstance}.
579 * Otherwise this method returns null.
580 *
581 * @return Policy parameters, or null.
582 *
583 * @since 1.6
584 */
585 public Policy.Parameters getParameters() {
586 return null;
587 }
588
589 /**
590 * Return a PermissionCollection object containing the set of
591 * permissions granted to the specified CodeSource.
592 *
593 * <p> Applications are discouraged from calling this method
594 * since this operation may not be supported by all policy implementations.
595 * Applications should solely rely on the {@code implies} method
596 * to perform policy checks. If an application absolutely must call
597 * a getPermissions method, it should call
598 * {@code getPermissions(ProtectionDomain)}.
599 *
600 * <p> The default implementation of this method returns
601 * Policy.UNSUPPORTED_EMPTY_COLLECTION. This method can be
602 * overridden if the policy implementation can return a set of
603 * permissions granted to a CodeSource.
604 *
605 * @param codesource the CodeSource to which the returned
606 * PermissionCollection has been granted.
607 *
608 * @return a set of permissions granted to the specified CodeSource.
609 * If this operation is supported, the returned
610 * set of permissions must be a new mutable instance
611 * and it must support heterogeneous Permission types.
612 * If this operation is not supported,
613 * Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
614 */
615 public PermissionCollection getPermissions(CodeSource codesource) {
616 return Policy.UNSUPPORTED_EMPTY_COLLECTION;
617 }
618
619 /**
620 * Return a PermissionCollection object containing the set of
621 * permissions granted to the specified ProtectionDomain.
622 *
623 * <p> Applications are discouraged from calling this method
624 * since this operation may not be supported by all policy implementations.
625 * Applications should rely on the {@code implies} method
626 * to perform policy checks.
627 *
628 * <p> The default implementation of this method first retrieves
629 * the permissions returned via {@code getPermissions(CodeSource)}
630 * (the CodeSource is taken from the specified ProtectionDomain),
631 * as well as the permissions located inside the specified ProtectionDomain.
632 * All of these permissions are then combined and returned in a new
633 * PermissionCollection object. If {@code getPermissions(CodeSource)}
634 * returns Policy.UNSUPPORTED_EMPTY_COLLECTION, then this method
635 * returns the permissions contained inside the specified ProtectionDomain
636 * in a new PermissionCollection object.
637 *
638 * <p> This method can be overridden if the policy implementation
639 * supports returning a set of permissions granted to a ProtectionDomain.
640 *
641 * @param domain the ProtectionDomain to which the returned
642 * PermissionCollection has been granted.
643 *
644 * @return a set of permissions granted to the specified ProtectionDomain.
645 * If this operation is supported, the returned
646 * set of permissions must be a new mutable instance
647 * and it must support heterogeneous Permission types.
648 * If this operation is not supported,
649 * Policy.UNSUPPORTED_EMPTY_COLLECTION is returned.
650 *
651 * @since 1.4
652 */
653 public PermissionCollection getPermissions(ProtectionDomain domain) {
654 PermissionCollection pc = null;
655
656 if (domain == null)
657 return new Permissions();
658
659 if (pdMapping == null) {
660 initPolicy(this);
661 }
662
663 synchronized (pdMapping) {
664 pc = pdMapping.get(domain.key);
665 }
666
667 if (pc != null) {
668 Permissions perms = new Permissions();
669 synchronized (pc) {
670 for (Enumeration<Permission> e = pc.elements() ; e.hasMoreElements() ;) {
671 perms.add(e.nextElement());
672 }
673 }
674 return perms;
675 }
676
677 pc = getPermissions(domain.getCodeSource());
678 if (pc == null || pc == UNSUPPORTED_EMPTY_COLLECTION) {
679 pc = new Permissions();
680 }
681
682 addStaticPerms(pc, domain.getPermissions());
683 return pc;
684 }
685
686 /**
687 * add static permissions to provided permission collection
688 */
689 private void addStaticPerms(PermissionCollection perms,
690 PermissionCollection statics) {
691 if (statics != null) {
692 synchronized (statics) {
693 Enumeration<Permission> e = statics.elements();
694 while (e.hasMoreElements()) {
695 perms.add(e.nextElement());
696 }
697 }
698 }
699 }
700
701 /**
702 * Evaluates the global policy for the permissions granted to
703 * the ProtectionDomain and tests whether the permission is
704 * granted.
705 *
706 * @param domain the ProtectionDomain to test
707 * @param permission the Permission object to be tested for implication.
708 *
709 * @return true if "permission" is a proper subset of a permission
710 * granted to this ProtectionDomain.
711 *
712 * @see java.security.ProtectionDomain
713 * @since 1.4
714 */
715 public boolean implies(ProtectionDomain domain, Permission permission) {
716 PermissionCollection pc;
717
718 if (pdMapping == null) {
719 initPolicy(this);
720 }
721
722 synchronized (pdMapping) {
723 pc = pdMapping.get(domain.key);
724 }
725
726 if (pc != null) {
727 return pc.implies(permission);
728 }
729
730 pc = getPermissions(domain);
731 if (pc == null) {
732 return false;
733 }
734
735 synchronized (pdMapping) {
736 // cache it
737 pdMapping.put(domain.key, pc);
738 }
739
740 return pc.implies(permission);
741 }
742
743 /**
744 * Refreshes/reloads the policy configuration. The behavior of this method
745 * depends on the implementation. For example, calling {@code refresh}
746 * on a file-based policy will cause the file to be re-read.
747 *
748 * <p> The default implementation of this method does nothing.
749 * This method should be overridden if a refresh operation is supported
750 * by the policy implementation.
751 */
752 public void refresh() { }
753
754 /**
755 * This subclass is returned by the getInstance calls. All Policy calls
756 * are delegated to the underlying PolicySpi.
757 */
758 private static class PolicyDelegate extends Policy {
759
760 private PolicySpi spi;
761 private Provider p;
762 private String type;
763 private Policy.Parameters params;
764
765 private PolicyDelegate(PolicySpi spi, Provider p,
766 String type, Policy.Parameters params) {
767 this.spi = spi;
768 this.p = p;
769 this.type = type;
770 this.params = params;
771 }
772
773 @Override public String getType() { return type; }
774
775 @Override public Policy.Parameters getParameters() { return params; }
776
777 @Override public Provider getProvider() { return p; }
778
779 @Override
780 public PermissionCollection getPermissions(CodeSource codesource) {
781 return spi.engineGetPermissions(codesource);
782 }
783 @Override
784 public PermissionCollection getPermissions(ProtectionDomain domain) {
785 return spi.engineGetPermissions(domain);
786 }
787 @Override
788 public boolean implies(ProtectionDomain domain, Permission perm) {
789 return spi.engineImplies(domain, perm);
790 }
791 @Override
792 public void refresh() {
793 spi.engineRefresh();
794 }
795 }
796
797 /**
798 * This represents a marker interface for Policy parameters.
799 *
800 * @since 1.6
801 */
802 public static interface Parameters { }
803
804 /**
805 * This class represents a read-only empty PermissionCollection object that
806 * is returned from the {@code getPermissions(CodeSource)} and
807 * {@code getPermissions(ProtectionDomain)}
808 * methods in the Policy class when those operations are not
809 * supported by the Policy implementation.
810 */
811 private static class UnsupportedEmptyCollection
812 extends PermissionCollection {
813
814 private static final long serialVersionUID = -8492269157353014774L;
815
816 private Permissions perms;
817
818 /**
819 * Create a read-only empty PermissionCollection object.
820 */
821 public UnsupportedEmptyCollection() {
822 this.perms = new Permissions();
823 perms.setReadOnly();
824 }
825
826 /**
827 * Adds a permission object to the current collection of permission
828 * objects.
829 *
830 * @param permission the Permission object to add.
831 *
832 * @exception SecurityException - if this PermissionCollection object
833 * has been marked readonly
834 */
835 @Override public void add(Permission permission) {
836 perms.add(permission);
837 }
838
839 /**
840 * Checks to see if the specified permission is implied by the
841 * collection of Permission objects held in this PermissionCollection.
842 *
843 * @param permission the Permission object to compare.
844 *
845 * @return true if "permission" is implied by the permissions in
846 * the collection, false if not.
847 */
848 @Override public boolean implies(Permission permission) {
849 return perms.implies(permission);
850 }
851
852 /**
853 * Returns an enumeration of all the Permission objects in the
854 * collection.
855 *
856 * @return an enumeration of all the Permissions.
857 */
858 @Override public Enumeration<Permission> elements() {
859 return perms.elements();
860 }
861 }
862 }