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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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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
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+import sun.security.util.Debug;
31+import sun.security.util.SecurityConstants;
32+import sun.misc.JavaSecurityAccess;
33+import sun.misc.SharedSecrets;
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</code>,
42+ * that is equivalent to the <code>checkPermission</code> method
43+ * in the AccessController class, with one difference: The AccessControlContext
44+ * <code>checkPermission</code> 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</code> method.
55+ * The <code>getContext</code> 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</code> 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+ */
78+
79+public final class AccessControlContext {
80+
81+ private ProtectionDomain context[];
82+ private boolean isPrivileged;
83+
84+ // Note: This field is directly used by the virtual machine
85+ // native codes. Don't touch it.
86+ private AccessControlContext privilegedContext;
87+
88+ private DomainCombiner combiner = null;
89+
90+ private static boolean debugInit = false;
91+ private static Debug debug = null;
92+
93+ static Debug getDebug()
94+ {
95+ if (debugInit)
96+ return debug;
97+ else {
98+ if (Policy.isSet()) {
99+ debug = Debug.getInstance("access");
100+ debugInit = true;
101+ }
102+ return debug;
103+ }
104+ }
105+
106+ /**
107+ * Create an AccessControlContext with the given array of ProtectionDomains.
108+ * Context must not be null. Duplicate domains will be removed from the
109+ * context.
110+ *
111+ * @param context the ProtectionDomains associated with this context.
112+ * The non-duplicate domains are copied from the array. Subsequent
113+ * changes to the array will not affect this AccessControlContext.
114+ * @throws NullPointerException if <code>context</code> is <code>null</code>
115+ */
116+ public AccessControlContext(ProtectionDomain context[])
117+ {
118+ if (context.length == 0) {
119+ this.context = null;
120+ } else if (context.length == 1) {
121+ if (context[0] != null) {
122+ this.context = context.clone();
123+ } else {
124+ this.context = null;
125+ }
126+ } else {
127+ List<ProtectionDomain> v = new ArrayList<>(context.length);
128+ for (int i =0; i< context.length; i++) {
129+ if ((context[i] != null) && (!v.contains(context[i])))
130+ v.add(context[i]);
131+ }
132+ if (!v.isEmpty()) {
133+ this.context = new ProtectionDomain[v.size()];
134+ this.context = v.toArray(this.context);
135+ }
136+ }
137+ }
138+
139+ /**
140+ * Create a new <code>AccessControlContext</code> with the given
141+ * <code>AccessControlContext</code> and <code>DomainCombiner</code>.
142+ * This constructor associates the provided
143+ * <code>DomainCombiner</code> with the provided
144+ * <code>AccessControlContext</code>.
145+ *
146+ * <p>
147+ *
148+ * @param acc the <code>AccessControlContext</code> associated
149+ * with the provided <code>DomainCombiner</code>.
150+ *
151+ * @param combiner the <code>DomainCombiner</code> to be associated
152+ * with the provided <code>AccessControlContext</code>.
153+ *
154+ * @exception NullPointerException if the provided
155+ * <code>context</code> is <code>null</code>.
156+ *
157+ * @exception SecurityException if a security manager is installed and the
158+ * caller does not have the "createAccessControlContext"
159+ * {@link SecurityPermission}
160+ * @since 1.3
161+ */
162+ public AccessControlContext(AccessControlContext acc,
163+ DomainCombiner combiner) {
164+
165+ SecurityManager sm = System.getSecurityManager();
166+ if (sm != null) {
167+ sm.checkPermission(SecurityConstants.CREATE_ACC_PERMISSION);
168+ }
169+
170+ this.context = acc.context;
171+
172+ // we do not need to run the combine method on the
173+ // provided ACC. it was already "combined" when the
174+ // context was originally retrieved.
175+ //
176+ // at this point in time, we simply throw away the old
177+ // combiner and use the newly provided one.
178+ this.combiner = combiner;
179+ }
180+
181+ /**
182+ * package private for AccessController
183+ */
184+ AccessControlContext(ProtectionDomain context[], DomainCombiner combiner) {
185+ if (context != null) {
186+ this.context = context.clone();
187+ }
188+ this.combiner = combiner;
189+ }
190+
191+ /**
192+ * package private constructor for AccessController.getContext()
193+ */
194+
195+ AccessControlContext(ProtectionDomain context[],
196+ boolean isPrivileged)
197+ {
198+ this.context = context;
199+ this.isPrivileged = isPrivileged;
200+ }
201+
202+ /**
203+ * Constructor for JavaSecurityAccess.doIntersectionPrivilege()
204+ */
205+ AccessControlContext(ProtectionDomain[] context,
206+ AccessControlContext privilegedContext)
207+ {
208+ this.context = context;
209+ this.privilegedContext = privilegedContext;
210+ this.isPrivileged = true;
211+ }
212+
213+ /**
214+ * Returns this context's context.
215+ */
216+ ProtectionDomain[] getContext() {
217+ return context;
218+ }
219+
220+ /**
221+ * Returns true if this context is privileged.
222+ */
223+ boolean isPrivileged()
224+ {
225+ return isPrivileged;
226+ }
227+
228+ /**
229+ * get the assigned combiner from the privileged or inherited context
230+ */
231+ DomainCombiner getAssignedCombiner() {
232+ AccessControlContext acc;
233+ if (isPrivileged) {
234+ acc = privilegedContext;
235+ } else {
236+ acc = AccessController.getInheritedAccessControlContext();
237+ }
238+ if (acc != null) {
239+ return acc.combiner;
240+ }
241+ return null;
242+ }
243+
244+ /**
245+ * Get the <code>DomainCombiner</code> associated with this
246+ * <code>AccessControlContext</code>.
247+ *
248+ * <p>
249+ *
250+ * @return the <code>DomainCombiner</code> associated with this
251+ * <code>AccessControlContext</code>, or <code>null</code>
252+ * if there is none.
253+ *
254+ * @exception SecurityException if a security manager is installed and
255+ * the caller does not have the "getDomainCombiner"
256+ * {@link SecurityPermission}
257+ * @since 1.3
258+ */
259+ public DomainCombiner getDomainCombiner() {
260+
261+ SecurityManager sm = System.getSecurityManager();
262+ if (sm != null) {
263+ sm.checkPermission(SecurityConstants.GET_COMBINER_PERMISSION);
264+ }
265+ return combiner;
266+ }
267+
268+ /**
269+ * Determines whether the access request indicated by the
270+ * specified permission should be allowed or denied, based on
271+ * the security policy currently in effect, and the context in
272+ * this object. The request is allowed only if every ProtectionDomain
273+ * in the context implies the permission. Otherwise the request is
274+ * denied.
275+ *
276+ * <p>
277+ * This method quietly returns if the access request
278+ * is permitted, or throws a suitable AccessControlException otherwise.
279+ *
280+ * @param perm the requested permission.
281+ *
282+ * @exception AccessControlException if the specified permission
283+ * is not permitted, based on the current security policy and the
284+ * context encapsulated by this object.
285+ * @exception NullPointerException if the permission to check for is null.
286+ */
287+ public void checkPermission(Permission perm)
288+ throws AccessControlException
289+ {
290+ boolean dumpDebug = false;
291+
292+ if (perm == null) {
293+ throw new NullPointerException("permission can't be null");
294+ }
295+ if (getDebug() != null) {
296+ // If "codebase" is not specified, we dump the info by default.
297+ dumpDebug = !Debug.isOn("codebase=");
298+ if (!dumpDebug) {
299+ // If "codebase" is specified, only dump if the specified code
300+ // value is in the stack.
301+ for (int i = 0; context != null && i < context.length; i++) {
302+ if (context[i].getCodeSource() != null &&
303+ context[i].getCodeSource().getLocation() != null &&
304+ Debug.isOn("codebase=" + context[i].getCodeSource().getLocation().toString())) {
305+ dumpDebug = true;
306+ break;
307+ }
308+ }
309+ }
310+
311+ dumpDebug &= !Debug.isOn("permission=") ||
312+ Debug.isOn("permission=" + perm.getClass().getCanonicalName());
313+
314+ if (dumpDebug && Debug.isOn("stack")) {
315+ Thread.currentThread().dumpStack();
316+ }
317+
318+ if (dumpDebug && Debug.isOn("domain")) {
319+ if (context == null) {
320+ debug.println("domain (context is null)");
321+ } else {
322+ for (int i=0; i< context.length; i++) {
323+ debug.println("domain "+i+" "+context[i]);
324+ }
325+ }
326+ }
327+ }
328+
329+ /*
330+ * iterate through the ProtectionDomains in the context.
331+ * Stop at the first one that doesn't allow the
332+ * requested permission (throwing an exception).
333+ *
334+ */
335+
336+ /* if ctxt is null, all we had on the stack were system domains,
337+ or the first domain was a Privileged system domain. This
338+ is to make the common case for system code very fast */
339+
340+ if (context == null)
341+ return;
342+
343+ for (int i=0; i< context.length; i++) {
344+ if (context[i] != null && !context[i].implies(perm)) {
345+ if (dumpDebug) {
346+ debug.println("access denied " + perm);
347+ }
348+
349+ if (Debug.isOn("failure") && debug != null) {
350+ // Want to make sure this is always displayed for failure,
351+ // but do not want to display again if already displayed
352+ // above.
353+ if (!dumpDebug) {
354+ debug.println("access denied " + perm);
355+ }
356+ Thread.currentThread().dumpStack();
357+ final ProtectionDomain pd = context[i];
358+ final Debug db = debug;
359+ AccessController.doPrivileged (new PrivilegedAction<Void>() {
360+ public Void run() {
361+ db.println("domain that failed "+pd);
362+ return null;
363+ }
364+ });
365+ }
366+ throw new AccessControlException("access denied "+perm, perm);
367+ }
368+ }
369+
370+ // allow if all of them allowed access
371+ if (dumpDebug) {
372+ debug.println("access allowed "+perm);
373+ }
374+
375+ return;
376+ }
377+
378+ /**
379+ * Take the stack-based context (this) and combine it with the
380+ * privileged or inherited context, if need be.
381+ */
382+ AccessControlContext optimize() {
383+ // the assigned (privileged or inherited) context
384+ AccessControlContext acc;
385+ if (isPrivileged) {
386+ acc = privilegedContext;
387+ } else {
388+ acc = AccessController.getInheritedAccessControlContext();
389+ }
390+
391+ // this.context could be null if only system code is on the stack;
392+ // in that case, ignore the stack context
393+ boolean skipStack = (context == null);
394+
395+ // acc.context could be null if only system code was involved;
396+ // in that case, ignore the assigned context
397+ boolean skipAssigned = (acc == null || acc.context == null);
398+
399+ if (acc != null && acc.combiner != null) {
400+ // let the assigned acc's combiner do its thing
401+ return goCombiner(context, acc);
402+ }
403+
404+ // optimization: if neither have contexts; return acc if possible
405+ // rather than this, because acc might have a combiner
406+ if (skipAssigned && skipStack) {
407+ return this;
408+ }
409+
410+ // optimization: if there is no stack context; there is no reason
411+ // to compress the assigned context, it already is compressed
412+ if (skipStack) {
413+ return acc;
414+ }
415+
416+ int slen = context.length;
417+
418+ // optimization: if there is no assigned context and the stack length
419+ // is less then or equal to two; there is no reason to compress the
420+ // stack context, it already is
421+ if (skipAssigned && slen <= 2) {
422+ return this;
423+ }
424+
425+ // optimization: if there is a single stack domain and that domain
426+ // is already in the assigned context; no need to combine
427+ if ((slen == 1) && (context[0] == acc.context[0])) {
428+ return acc;
429+ }
430+
431+ int n = (skipAssigned) ? 0 : acc.context.length;
432+
433+ // now we combine both of them, and create a new context
434+ ProtectionDomain pd[] = new ProtectionDomain[slen + n];
435+
436+ // first copy in the assigned context domains, no need to compress
437+ if (!skipAssigned) {
438+ System.arraycopy(acc.context, 0, pd, 0, n);
439+ }
440+
441+ // now add the stack context domains, discarding nulls and duplicates
442+ outer:
443+ for (int i = 0; i < context.length; i++) {
444+ ProtectionDomain sd = context[i];
445+ if (sd != null) {
446+ for (int j = 0; j < n; j++) {
447+ if (sd == pd[j]) {
448+ continue outer;
449+ }
450+ }
451+ pd[n++] = sd;
452+ }
453+ }
454+
455+ // if length isn't equal, we need to shorten the array
456+ if (n != pd.length) {
457+ // optimization: if we didn't really combine anything
458+ if (!skipAssigned && n == acc.context.length) {
459+ return acc;
460+ } else if (skipAssigned && n == slen) {
461+ return this;
462+ }
463+ ProtectionDomain tmp[] = new ProtectionDomain[n];
464+ System.arraycopy(pd, 0, tmp, 0, n);
465+ pd = tmp;
466+ }
467+
468+ // return new AccessControlContext(pd, false);
469+
470+ // Reuse existing ACC
471+
472+ this.context = pd;
473+ this.combiner = null;
474+ this.isPrivileged = false;
475+
476+ return this;
477+ }
478+
479+ private AccessControlContext goCombiner(ProtectionDomain[] current,
480+ AccessControlContext assigned) {
481+
482+ // the assigned ACC's combiner is not null --
483+ // let the combiner do its thing
484+
485+ // XXX we could add optimizations to 'current' here ...
486+
487+ if (getDebug() != null) {
488+ debug.println("AccessControlContext invoking the Combiner");
489+ }
490+
491+ // No need to clone current and assigned.context
492+ // combine() will not update them
493+ ProtectionDomain[] combinedPds = assigned.combiner.combine(
494+ current, assigned.context);
495+
496+ // return new AccessControlContext(combinedPds, assigned.combiner);
497+
498+ // Reuse existing ACC
499+ this.context = combinedPds;
500+ this.combiner = assigned.combiner;
501+ this.isPrivileged = false;
502+
503+ return this;
504+ }
505+
506+ /**
507+ * Checks two AccessControlContext objects for equality.
508+ * Checks that <i>obj</i> is
509+ * an AccessControlContext and has the same set of ProtectionDomains
510+ * as this context.
511+ * <P>
512+ * @param obj the object we are testing for equality with this object.
513+ * @return true if <i>obj</i> is an AccessControlContext, and has the
514+ * same set of ProtectionDomains as this context, false otherwise.
515+ */
516+ public boolean equals(Object obj) {
517+ if (obj == this)
518+ return true;
519+
520+ if (! (obj instanceof AccessControlContext))
521+ return false;
522+
523+ AccessControlContext that = (AccessControlContext) obj;
524+
525+
526+ if (context == null) {
527+ return (that.context == null);
528+ }
529+
530+ if (that.context == null)
531+ return false;
532+
533+ if (!(this.containsAllPDs(that) && that.containsAllPDs(this)))
534+ return false;
535+
536+ if (this.combiner == null)
537+ return (that.combiner == null);
538+
539+ if (that.combiner == null)
540+ return false;
541+
542+ if (!this.combiner.equals(that.combiner))
543+ return false;
544+
545+ return true;
546+ }
547+
548+ private boolean containsAllPDs(AccessControlContext that) {
549+ boolean match = false;
550+ //
551+ // ProtectionDomains within an ACC currently cannot be null
552+ // and this is enforced by the constructor and the various
553+ // optimize methods. However, historically this logic made attempts
554+ // to support the notion of a null PD and therefore this logic continues
555+ // to support that notion.
556+ ProtectionDomain thisPd;
557+ for (int i = 0; i < context.length; i++) {
558+ match = false;
559+ if ((thisPd = context[i]) == null) {
560+ for (int j = 0; (j < that.context.length) && !match; j++) {
561+ match = (that.context[j] == null);
562+ }
563+ } else {
564+ Class thisPdClass = thisPd.getClass();
565+ ProtectionDomain thatPd;
566+ for (int j = 0; (j < that.context.length) && !match; j++) {
567+ thatPd = that.context[j];
568+
569+ // Class check required to avoid PD exposure (4285406)
570+ match = (thatPd != null &&
571+ thisPdClass == thatPd.getClass() && thisPd.equals(thatPd));
572+ }
573+ }
574+ if (!match) return false;
575+ }
576+ return match;
577+ }
578+ /**
579+ * Returns the hash code value for this context. The hash code
580+ * is computed by exclusive or-ing the hash code of all the protection
581+ * domains in the context together.
582+ *
583+ * @return a hash code value for this context.
584+ */
585+
586+ public int hashCode() {
587+ int hashCode = 0;
588+
589+ if (context == null)
590+ return hashCode;
591+
592+ for (int i =0; i < context.length; i++) {
593+ if (context[i] != null)
594+ hashCode ^= context[i].hashCode();
595+ }
596+ return hashCode;
597+ }
598+}