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
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 java.security;
27
28 import java.util.ArrayList;
29 import java.util.List;
30
31 import sun.security.util.Debug;
32 import sun.security.util.FilePermCompat;
33 import sun.security.util.SecurityConstants;
34
35
36 /**
37 * An AccessControlContext is used to make system resource access decisions
38 * based on the context it encapsulates.
39 *
40 * <p>More specifically, it encapsulates a context and
41 * has a single method, {@code checkPermission},
42 * that is equivalent to the {@code checkPermission} method
43 * in the AccessController class, with one difference: The AccessControlContext
44 * {@code checkPermission} method makes access decisions based on the
45 * context it encapsulates,
46 * rather than that of the current execution thread.
47 *
48 * <p>Thus, the purpose of AccessControlContext is for those situations where
49 * a security check that should be made within a given context
50 * actually needs to be done from within a
51 * <i>different</i> context (for example, from within a worker thread).
52 *
53 * <p> An AccessControlContext is created by calling the
54 * {@code AccessController.getContext} method.
55 * The {@code getContext} method takes a "snapshot"
56 * of the current calling context, and places
57 * it in an AccessControlContext object, which it returns. A sample call is
58 * the following:
59 *
60 * <pre>
61 * AccessControlContext acc = AccessController.getContext()
62 * </pre>
63 *
64 * <p>
65 * Code within a different context can subsequently call the
66 * {@code checkPermission} method on the
67 * previously-saved AccessControlContext object. A sample call is the
68 * following:
69 *
70 * <pre>
71 * acc.checkPermission(permission)
72 * </pre>
73 *
74 * @see AccessController
75 *
76 * @author Roland Schemers
77 * @since 1.2
78 */
79
80 public final class AccessControlContext {
81
82 private ProtectionDomain[] context;
83 // isPrivileged and isAuthorized are referenced by the VM - do not remove
84 // or change their names
85 private boolean isPrivileged;
86 private boolean isAuthorized = false;
87
88 // Note: This field is directly used by the virtual machine
89 // native codes. Don't touch it.
90 private AccessControlContext privilegedContext;
91
92 private DomainCombiner combiner = null;
93
94 // limited privilege scope
95 private Permission[] permissions;
96 private AccessControlContext parent;
97 private boolean isWrapped;
98
99 // is constrained by limited privilege scope?
100 private boolean isLimited;
101 private ProtectionDomain[] limitedContext;
102
103 private static boolean debugInit = false;
104 private static Debug debug = null;
105
106 static Debug getDebug()
107 {
108 if (debugInit)
109 return debug;
110 else {
111 if (Policy.isSet()) {
112 debug = Debug.getInstance("access");
113 debugInit = true;
114 }
115 return debug;
116 }
117 }
118
119 /**
120 * Create an AccessControlContext with the given array of ProtectionDomains.
121 * Context must not be null. Duplicate domains will be removed from the
122 * context.
123 *
124 * @param context the ProtectionDomains associated with this context.
125 * The non-duplicate domains are copied from the array. Subsequent
126 * changes to the array will not affect this AccessControlContext.
127 * @throws NullPointerException if {@code context} is {@code null}
128 */
129 public AccessControlContext(ProtectionDomain[] context)
130 {
131 if (context.length == 0) {
132 this.context = null;
133 } else if (context.length == 1) {
134 if (context[0] != null) {
135 this.context = context.clone();
136 } else {
137 this.context = null;
138 }
139 } else {
140 List<ProtectionDomain> v = new ArrayList<>(context.length);
141 for (int i =0; i< context.length; i++) {
142 if ((context[i] != null) && (!v.contains(context[i])))
143 v.add(context[i]);
144 }
145 if (!v.isEmpty()) {
146 this.context = new ProtectionDomain[v.size()];
147 this.context = v.toArray(this.context);
148 }
149 }
150 }
151
152 /**
153 * Create a new {@code AccessControlContext} with the given
154 * {@code AccessControlContext} and {@code DomainCombiner}.
155 * This constructor associates the provided
156 * {@code DomainCombiner} with the provided
157 * {@code AccessControlContext}.
158 *
159 * @param acc the {@code AccessControlContext} associated
160 * with the provided {@code DomainCombiner}.
161 *
162 * @param combiner the {@code DomainCombiner} to be associated
163 * with the provided {@code AccessControlContext}.
164 *
165 * @exception NullPointerException if the provided
166 * {@code context} is {@code null}.
167 *
168 * @exception SecurityException if a security manager is installed and the
169 * caller does not have the "createAccessControlContext"
170 * {@link SecurityPermission}
171 * @since 1.3
172 */
173 public AccessControlContext(AccessControlContext acc,
174 DomainCombiner combiner) {
175
176 this(acc, combiner, false);
177 }
178
179 /**
180 * package private to allow calls from ProtectionDomain without performing
181 * the security check for {@linkplain SecurityConstants#CREATE_ACC_PERMISSION}
182 * permission
183 */
184 AccessControlContext(AccessControlContext acc,
185 DomainCombiner combiner,
186 boolean preauthorized) {
187 if (!preauthorized) {
188 SecurityManager sm = System.getSecurityManager();
189 if (sm != null) {
190 sm.checkPermission(SecurityConstants.CREATE_ACC_PERMISSION);
191 this.isAuthorized = true;
192 }
193 } else {
194 this.isAuthorized = true;
195 }
196
197 this.context = acc.context;
198
199 // we do not need to run the combine method on the
200 // provided ACC. it was already "combined" when the
201 // context was originally retrieved.
202 //
203 // at this point in time, we simply throw away the old
204 // combiner and use the newly provided one.
205 this.combiner = combiner;
206 }
207
208 /**
209 * package private for AccessController
210 *
211 * This "argument wrapper" context will be passed as the actual context
212 * parameter on an internal doPrivileged() call used in the implementation.
213 */
214 AccessControlContext(ProtectionDomain caller, DomainCombiner combiner,
215 AccessControlContext parent, AccessControlContext context,
216 Permission[] perms)
217 {
218 /*
219 * Combine the domains from the doPrivileged() context into our
220 * wrapper context, if necessary.
221 */
222 ProtectionDomain[] callerPDs = null;
223 if (caller != null) {
224 callerPDs = new ProtectionDomain[] { caller };
225 }
226 if (context != null) {
227 if (combiner != null) {
228 this.context = combiner.combine(callerPDs, context.context);
229 } else {
230 this.context = combine(callerPDs, context.context);
231 }
232 } else {
233 /*
234 * Call combiner even if there is seemingly nothing to combine.
235 */
236 if (combiner != null) {
237 this.context = combiner.combine(callerPDs, null);
238 } else {
239 this.context = combine(callerPDs, null);
240 }
241 }
242 this.combiner = combiner;
243
244 Permission[] tmp = null;
245 if (perms != null) {
246 tmp = new Permission[perms.length];
247 for (int i=0; i < perms.length; i++) {
248 if (perms[i] == null) {
249 throw new NullPointerException("permission can't be null");
250 }
251
252 /*
253 * An AllPermission argument is equivalent to calling
254 * doPrivileged() without any limit permissions.
255 */
256 if (perms[i].getClass() == AllPermission.class) {
257 parent = null;
258 }
259 // Add altPath into permission for compatibility.
260 tmp[i] = FilePermCompat.newPermPlusAltPath(perms[i]);
261 }
262 }
263
264 /*
265 * For a doPrivileged() with limited privilege scope, initialize
266 * the relevant fields.
267 *
268 * The limitedContext field contains the union of all domains which
269 * are enclosed by this limited privilege scope. In other words,
270 * it contains all of the domains which could potentially be checked
271 * if none of the limiting permissions implied a requested permission.
272 */
273 if (parent != null) {
274 this.limitedContext = combine(parent.context, parent.limitedContext);
275 this.isLimited = true;
276 this.isWrapped = true;
277 this.permissions = tmp;
278 this.parent = parent;
279 this.privilegedContext = context; // used in checkPermission2()
280 }
281 this.isAuthorized = true;
282 }
283
284
285 /**
286 * package private constructor for AccessController.getContext()
287 */
288
289 AccessControlContext(ProtectionDomain[] context,
290 boolean isPrivileged)
291 {
292 this.context = context;
293 this.isPrivileged = isPrivileged;
294 this.isAuthorized = true;
295 }
296
297 /**
298 * Constructor for JavaSecurityAccess.doIntersectionPrivilege()
299 */
300 AccessControlContext(ProtectionDomain[] context,
301 AccessControlContext privilegedContext)
302 {
303 this.context = context;
304 this.privilegedContext = privilegedContext;
305 this.isPrivileged = true;
306 }
307
308 /**
309 * Returns this context's context.
310 */
311 ProtectionDomain[] getContext() {
312 return context;
313 }
314
315 /**
316 * Returns true if this context is privileged.
317 */
318 boolean isPrivileged()
319 {
320 return isPrivileged;
321 }
322
323 /**
324 * get the assigned combiner from the privileged or inherited context
325 */
326 DomainCombiner getAssignedCombiner() {
327 AccessControlContext acc;
328 if (isPrivileged) {
329 acc = privilegedContext;
330 } else {
331 acc = AccessController.getInheritedAccessControlContext();
332 }
333 if (acc != null) {
334 return acc.combiner;
335 }
336 return null;
337 }
338
339 /**
340 * Get the {@code DomainCombiner} associated with this
341 * {@code AccessControlContext}.
342 *
343 * @return the {@code DomainCombiner} associated with this
344 * {@code AccessControlContext}, or {@code null}
345 * if there is none.
346 *
347 * @exception SecurityException if a security manager is installed and
348 * the caller does not have the "getDomainCombiner"
349 * {@link SecurityPermission}
350 * @since 1.3
351 */
352 public DomainCombiner getDomainCombiner() {
353
354 SecurityManager sm = System.getSecurityManager();
355 if (sm != null) {
356 sm.checkPermission(SecurityConstants.GET_COMBINER_PERMISSION);
357 }
358 return getCombiner();
359 }
360
361 /**
362 * package private for AccessController
363 */
364 DomainCombiner getCombiner() {
365 return combiner;
366 }
367
368 boolean isAuthorized() {
369 return isAuthorized;
370 }
371
372 /**
373 * Determines whether the access request indicated by the
374 * specified permission should be allowed or denied, based on
375 * the security policy currently in effect, and the context in
376 * this object. The request is allowed only if every ProtectionDomain
377 * in the context implies the permission. Otherwise the request is
378 * denied.
379 *
380 * <p>
381 * This method quietly returns if the access request
382 * is permitted, or throws a suitable AccessControlException otherwise.
383 *
384 * @param perm the requested permission.
385 *
386 * @exception AccessControlException if the specified permission
387 * is not permitted, based on the current security policy and the
388 * context encapsulated by this object.
389 * @exception NullPointerException if the permission to check for is null.
390 */
391 public void checkPermission(Permission perm)
392 throws AccessControlException
393 {
394 boolean dumpDebug = false;
395
396 if (perm == null) {
397 throw new NullPointerException("permission can't be null");
398 }
399 if (getDebug() != null) {
400 // If "codebase" is not specified, we dump the info by default.
401 dumpDebug = !Debug.isOn("codebase=");
402 if (!dumpDebug) {
403 // If "codebase" is specified, only dump if the specified code
404 // value is in the stack.
405 for (int i = 0; context != null && i < context.length; i++) {
406 if (context[i].getCodeSource() != null &&
407 context[i].getCodeSource().getLocation() != null &&
408 Debug.isOn("codebase=" + context[i].getCodeSource().getLocation().toString())) {
409 dumpDebug = true;
410 break;
411 }
412 }
413 }
414
415 dumpDebug &= !Debug.isOn("permission=") ||
416 Debug.isOn("permission=" + perm.getClass().getCanonicalName());
417
418 if (dumpDebug && Debug.isOn("stack")) {
419 Thread.dumpStack();
420 }
421
422 if (dumpDebug && Debug.isOn("domain")) {
423 if (context == null) {
424 debug.println("domain (context is null)");
425 } else {
426 for (int i=0; i< context.length; i++) {
427 debug.println("domain "+i+" "+context[i]);
428 }
429 }
430 }
431 }
432
433 /*
434 * iterate through the ProtectionDomains in the context.
435 * Stop at the first one that doesn't allow the
436 * requested permission (throwing an exception).
437 *
438 */
439
440 /* if ctxt is null, all we had on the stack were system domains,
441 or the first domain was a Privileged system domain. This
442 is to make the common case for system code very fast */
443
444 if (context == null) {
445 checkPermission2(perm);
446 return;
447 }
448
449 for (int i=0; i< context.length; i++) {
450 if (context[i] != null && !context[i].impliesWithAltFilePerm(perm)) {
451 if (dumpDebug) {
452 debug.println("access denied " + perm);
453 }
454
455 if (Debug.isOn("failure") && debug != null) {
456 // Want to make sure this is always displayed for failure,
457 // but do not want to display again if already displayed
458 // above.
459 if (!dumpDebug) {
460 debug.println("access denied " + perm);
461 }
462 Thread.dumpStack();
463 final ProtectionDomain pd = context[i];
464 final Debug db = debug;
465 AccessController.doPrivileged (new PrivilegedAction<>() {
466 public Void run() {
467 db.println("domain that failed "+pd);
468 return null;
469 }
470 });
471 }
472 throw new AccessControlException("access denied "+perm, perm);
473 }
474 }
475
476 // allow if all of them allowed access
477 if (dumpDebug) {
478 debug.println("access allowed "+perm);
479 }
480
481 checkPermission2(perm);
482 }
483
484 /*
485 * Check the domains associated with the limited privilege scope.
486 */
487 private void checkPermission2(Permission perm) {
488 if (!isLimited) {
489 return;
490 }
491
492 /*
493 * Check the doPrivileged() context parameter, if present.
494 */
495 if (privilegedContext != null) {
496 privilegedContext.checkPermission2(perm);
497 }
498
499 /*
500 * Ignore the limited permissions and parent fields of a wrapper
501 * context since they were already carried down into the unwrapped
502 * context.
503 */
504 if (isWrapped) {
505 return;
506 }
507
508 /*
509 * Try to match any limited privilege scope.
510 */
511 if (permissions != null) {
512 Class<?> permClass = perm.getClass();
513 for (int i=0; i < permissions.length; i++) {
514 Permission limit = permissions[i];
515 if (limit.getClass().equals(permClass) && limit.implies(perm)) {
516 return;
517 }
518 }
519 }
520
521 /*
522 * Check the limited privilege scope up the call stack or the inherited
523 * parent thread call stack of this ACC.
524 */
525 if (parent != null) {
526 /*
527 * As an optimization, if the parent context is the inherited call
528 * stack context from a parent thread then checking the protection
529 * domains of the parent context is redundant since they have
530 * already been merged into the child thread's context by
531 * optimize(). When parent is set to an inherited context this
532 * context was not directly created by a limited scope
533 * doPrivileged() and it does not have its own limited permissions.
534 */
535 if (permissions == null) {
536 parent.checkPermission2(perm);
537 } else {
538 parent.checkPermission(perm);
539 }
540 }
541 }
542
543 /**
544 * Take the stack-based context (this) and combine it with the
545 * privileged or inherited context, if need be. Any limited
546 * privilege scope is flagged regardless of whether the assigned
547 * context comes from an immediately enclosing limited doPrivileged().
548 * The limited privilege scope can indirectly flow from the inherited
549 * parent thread or an assigned context previously captured by getContext().
550 */
551 AccessControlContext optimize() {
552 // the assigned (privileged or inherited) context
553 AccessControlContext acc;
554 DomainCombiner combiner = null;
555 AccessControlContext parent = null;
556 Permission[] permissions = null;
557
558 if (isPrivileged) {
559 acc = privilegedContext;
560 if (acc != null) {
561 /*
562 * If the context is from a limited scope doPrivileged() then
563 * copy the permissions and parent fields out of the wrapper
564 * context that was created to hold them.
565 */
566 if (acc.isWrapped) {
567 permissions = acc.permissions;
568 parent = acc.parent;
569 }
570 }
571 } else {
572 acc = AccessController.getInheritedAccessControlContext();
573 if (acc != null) {
574 /*
575 * If the inherited context is constrained by a limited scope
576 * doPrivileged() then set it as our parent so we will process
577 * the non-domain-related state.
578 */
579 if (acc.isLimited) {
580 parent = acc;
581 }
582 }
583 }
584
585 // this.context could be null if only system code is on the stack;
586 // in that case, ignore the stack context
587 boolean skipStack = (context == null);
588
589 // acc.context could be null if only system code was involved;
590 // in that case, ignore the assigned context
591 boolean skipAssigned = (acc == null || acc.context == null);
592 ProtectionDomain[] assigned = (skipAssigned) ? null : acc.context;
593 ProtectionDomain[] pd;
594
595 // if there is no enclosing limited privilege scope on the stack or
596 // inherited from a parent thread
597 boolean skipLimited = ((acc == null || !acc.isWrapped) && parent == null);
598
599 if (acc != null && acc.combiner != null) {
600 // let the assigned acc's combiner do its thing
601 if (getDebug() != null) {
602 debug.println("AccessControlContext invoking the Combiner");
603 }
604
605 // No need to clone current and assigned.context
606 // combine() will not update them
607 combiner = acc.combiner;
608 pd = combiner.combine(context, assigned);
609 } else {
610 if (skipStack) {
611 if (skipAssigned) {
612 calculateFields(acc, parent, permissions);
613 return this;
614 } else if (skipLimited) {
615 return acc;
616 }
617 } else if (assigned != null) {
618 if (skipLimited) {
619 // optimization: if there is a single stack domain and
620 // that domain is already in the assigned context; no
621 // need to combine
622 if (context.length == 1 && context[0] == assigned[0]) {
623 return acc;
624 }
625 }
626 }
627
628 pd = combine(context, assigned);
629 if (skipLimited && !skipAssigned && pd == assigned) {
630 return acc;
631 } else if (skipAssigned && pd == context) {
632 calculateFields(acc, parent, permissions);
633 return this;
634 }
635 }
636
637 // Reuse existing ACC
638 this.context = pd;
639 this.combiner = combiner;
640 this.isPrivileged = false;
641
642 calculateFields(acc, parent, permissions);
643 return this;
644 }
645
646
647 /*
648 * Combine the current (stack) and assigned domains.
649 */
650 private static ProtectionDomain[] combine(ProtectionDomain[] current,
651 ProtectionDomain[] assigned) {
652
653 // current could be null if only system code is on the stack;
654 // in that case, ignore the stack context
655 boolean skipStack = (current == null);
656
657 // assigned could be null if only system code was involved;
658 // in that case, ignore the assigned context
659 boolean skipAssigned = (assigned == null);
660
661 int slen = (skipStack) ? 0 : current.length;
662
663 // optimization: if there is no assigned context and the stack length
664 // is less then or equal to two; there is no reason to compress the
665 // stack context, it already is
666 if (skipAssigned && slen <= 2) {
667 return current;
668 }
669
670 int n = (skipAssigned) ? 0 : assigned.length;
671
672 // now we combine both of them, and create a new context
673 ProtectionDomain[] pd = new ProtectionDomain[slen + n];
674
675 // first copy in the assigned context domains, no need to compress
676 if (!skipAssigned) {
677 System.arraycopy(assigned, 0, pd, 0, n);
678 }
679
680 // now add the stack context domains, discarding nulls and duplicates
681 outer:
682 for (int i = 0; i < slen; i++) {
683 ProtectionDomain sd = current[i];
684 if (sd != null) {
685 for (int j = 0; j < n; j++) {
686 if (sd == pd[j]) {
687 continue outer;
688 }
689 }
690 pd[n++] = sd;
691 }
692 }
693
694 // if length isn't equal, we need to shorten the array
695 if (n != pd.length) {
696 // optimization: if we didn't really combine anything
697 if (!skipAssigned && n == assigned.length) {
698 return assigned;
699 } else if (skipAssigned && n == slen) {
700 return current;
701 }
702 ProtectionDomain[] tmp = new ProtectionDomain[n];
703 System.arraycopy(pd, 0, tmp, 0, n);
704 pd = tmp;
705 }
706
707 return pd;
708 }
709
710
711 /*
712 * Calculate the additional domains that could potentially be reached via
713 * limited privilege scope. Mark the context as being subject to limited
714 * privilege scope unless the reachable domains (if any) are already
715 * contained in this domain context (in which case any limited
716 * privilege scope checking would be redundant).
717 */
718 private void calculateFields(AccessControlContext assigned,
719 AccessControlContext parent, Permission[] permissions)
720 {
721 ProtectionDomain[] parentLimit = null;
722 ProtectionDomain[] assignedLimit = null;
723 ProtectionDomain[] newLimit;
724
725 parentLimit = (parent != null)? parent.limitedContext: null;
726 assignedLimit = (assigned != null)? assigned.limitedContext: null;
727 newLimit = combine(parentLimit, assignedLimit);
728 if (newLimit != null) {
729 if (context == null || !containsAllPDs(newLimit, context)) {
730 this.limitedContext = newLimit;
731 this.permissions = permissions;
732 this.parent = parent;
733 this.isLimited = true;
734 }
735 }
736 }
737
738
739 /**
740 * Checks two AccessControlContext objects for equality.
741 * Checks that {@code obj} is
742 * an AccessControlContext and has the same set of ProtectionDomains
743 * as this context.
744 *
745 * @param obj the object we are testing for equality with this object.
746 * @return true if {@code obj} is an AccessControlContext, and has the
747 * same set of ProtectionDomains as this context, false otherwise.
748 */
749 public boolean equals(Object obj) {
750 if (obj == this)
751 return true;
752
753 if (! (obj instanceof AccessControlContext))
754 return false;
755
756 AccessControlContext that = (AccessControlContext) obj;
757
758 if (!equalContext(that))
759 return false;
760
761 if (!equalLimitedContext(that))
762 return false;
763
764 return true;
765 }
766
767 /*
768 * Compare for equality based on state that is free of limited
769 * privilege complications.
770 */
771 private boolean equalContext(AccessControlContext that) {
772 if (!equalPDs(this.context, that.context))
773 return false;
774
775 if (this.combiner == null && that.combiner != null)
776 return false;
777
778 if (this.combiner != null && !this.combiner.equals(that.combiner))
779 return false;
780
781 return true;
782 }
783
784 private boolean equalPDs(ProtectionDomain[] a, ProtectionDomain[] b) {
785 if (a == null) {
786 return (b == null);
787 }
788
789 if (b == null)
790 return false;
791
792 if (!(containsAllPDs(a, b) && containsAllPDs(b, a)))
793 return false;
794
795 return true;
796 }
797
798 /*
799 * Compare for equality based on state that is captured during a
800 * call to AccessController.getContext() when a limited privilege
801 * scope is in effect.
802 */
803 private boolean equalLimitedContext(AccessControlContext that) {
804 if (that == null)
805 return false;
806
807 /*
808 * If neither instance has limited privilege scope then we're done.
809 */
810 if (!this.isLimited && !that.isLimited)
811 return true;
812
813 /*
814 * If only one instance has limited privilege scope then we're done.
815 */
816 if (!(this.isLimited && that.isLimited))
817 return false;
818
819 /*
820 * Wrapped instances should never escape outside the implementation
821 * this class and AccessController so this will probably never happen
822 * but it only makes any sense to compare if they both have the same
823 * isWrapped state.
824 */
825 if ((this.isWrapped && !that.isWrapped) ||
826 (!this.isWrapped && that.isWrapped)) {
827 return false;
828 }
829
830 if (this.permissions == null && that.permissions != null)
831 return false;
832
833 if (this.permissions != null && that.permissions == null)
834 return false;
835
836 if (!(this.containsAllLimits(that) && that.containsAllLimits(this)))
837 return false;
838
839 /*
840 * Skip through any wrapped contexts.
841 */
842 AccessControlContext thisNextPC = getNextPC(this);
843 AccessControlContext thatNextPC = getNextPC(that);
844
845 /*
846 * The protection domains and combiner of a privilegedContext are
847 * not relevant because they have already been included in the context
848 * of this instance by optimize() so we only care about any limited
849 * privilege state they may have.
850 */
851 if (thisNextPC == null && thatNextPC != null && thatNextPC.isLimited)
852 return false;
853
854 if (thisNextPC != null && !thisNextPC.equalLimitedContext(thatNextPC))
855 return false;
856
857 if (this.parent == null && that.parent != null)
858 return false;
859
860 if (this.parent != null && !this.parent.equals(that.parent))
861 return false;
862
863 return true;
864 }
865
866 /*
867 * Follow the privilegedContext link making our best effort to skip
868 * through any wrapper contexts.
869 */
870 private static AccessControlContext getNextPC(AccessControlContext acc) {
871 while (acc != null && acc.privilegedContext != null) {
872 acc = acc.privilegedContext;
873 if (!acc.isWrapped)
874 return acc;
875 }
876 return null;
877 }
878
879 private static boolean containsAllPDs(ProtectionDomain[] thisContext,
880 ProtectionDomain[] thatContext) {
881 boolean match = false;
882
883 //
884 // ProtectionDomains within an ACC currently cannot be null
885 // and this is enforced by the constructor and the various
886 // optimize methods. However, historically this logic made attempts
887 // to support the notion of a null PD and therefore this logic continues
888 // to support that notion.
889 ProtectionDomain thisPd;
890 for (int i = 0; i < thisContext.length; i++) {
891 match = false;
892 if ((thisPd = thisContext[i]) == null) {
893 for (int j = 0; (j < thatContext.length) && !match; j++) {
894 match = (thatContext[j] == null);
895 }
896 } else {
897 Class<?> thisPdClass = thisPd.getClass();
898 ProtectionDomain thatPd;
899 for (int j = 0; (j < thatContext.length) && !match; j++) {
900 thatPd = thatContext[j];
901
902 // Class check required to avoid PD exposure (4285406)
903 match = (thatPd != null &&
904 thisPdClass == thatPd.getClass() && thisPd.equals(thatPd));
905 }
906 }
907 if (!match) return false;
908 }
909 return match;
910 }
911
912 private boolean containsAllLimits(AccessControlContext that) {
913 boolean match = false;
914 Permission thisPerm;
915
916 if (this.permissions == null && that.permissions == null)
917 return true;
918
919 for (int i = 0; i < this.permissions.length; i++) {
920 Permission limit = this.permissions[i];
921 Class <?> limitClass = limit.getClass();
922 match = false;
923 for (int j = 0; (j < that.permissions.length) && !match; j++) {
924 Permission perm = that.permissions[j];
925 match = (limitClass.equals(perm.getClass()) &&
926 limit.equals(perm));
927 }
928 if (!match) return false;
929 }
930 return match;
931 }
932
933
934 /**
935 * Returns the hash code value for this context. The hash code
936 * is computed by exclusive or-ing the hash code of all the protection
937 * domains in the context together.
938 *
939 * @return a hash code value for this context.
940 */
941
942 public int hashCode() {
943 int hashCode = 0;
944
945 if (context == null)
946 return hashCode;
947
948 for (int i =0; i < context.length; i++) {
949 if (context[i] != null)
950 hashCode ^= context[i].hashCode();
951 }
952
953 return hashCode;
954 }
955 }