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25 
26 package javax.security.auth;
27 
28 import java.util.*;
29 import java.io.*;
30 import java.lang.reflect.*;
31 import java.text.MessageFormat;
32 import java.security.AccessController;
33 import java.security.AccessControlContext;
34 import java.security.DomainCombiner;
35 import java.security.Permission;
36 import java.security.PermissionCollection;
37 import java.security.Principal;
38 import java.security.PrivilegedAction;
39 import java.security.PrivilegedExceptionAction;
40 import java.security.PrivilegedActionException;
41 import java.security.ProtectionDomain;
42 import sun.security.util.ResourcesMgr;
43 
44 /**
45  * <p> A {@code Subject} represents a grouping of related information
46  * for a single entity, such as a person.
47  * Such information includes the Subject's identities as well as
48  * its security-related attributes
49  * (passwords and cryptographic keys, for example).
50  *
51  * <p> Subjects may potentially have multiple identities.
52  * Each identity is represented as a {@code Principal}
53  * within the {@code Subject}.  Principals simply bind names to a
54  * {@code Subject}.  For example, a {@code Subject} that happens
55  * to be a person, Alice, might have two Principals:
56  * one which binds "Alice Bar", the name on her driver license,
57  * to the {@code Subject}, and another which binds,
58  * "999-99-9999", the number on her student identification card,
59  * to the {@code Subject}.  Both Principals refer to the same
60  * {@code Subject} even though each has a different name.
61  *
62  * <p> A {@code Subject} may also own security-related attributes,
63  * which are referred to as credentials.
64  * Sensitive credentials that require special protection, such as
65  * private cryptographic keys, are stored within a private credential
66  * {@code Set}.  Credentials intended to be shared, such as
67  * public key certificates or Kerberos server tickets are stored
68  * within a public credential {@code Set}.  Different permissions
69  * are required to access and modify the different credential Sets.
70  *
71  * <p> To retrieve all the Principals associated with a {@code Subject},
72  * invoke the {@code getPrincipals} method.  To retrieve
73  * all the public or private credentials belonging to a {@code Subject},
74  * invoke the {@code getPublicCredentials} method or
75  * {@code getPrivateCredentials} method, respectively.
76  * To modify the returned {@code Set} of Principals and credentials,
77  * use the methods defined in the {@code Set} class.
78  * For example:
79  * <pre>
80  *      Subject subject;
81  *      Principal principal;
82  *      Object credential;
83  *
84  *      // add a Principal and credential to the Subject
85  *      subject.getPrincipals().add(principal);
86  *      subject.getPublicCredentials().add(credential);
87  * </pre>
88  *
89  * <p> This {@code Subject} class implements {@code Serializable}.
90  * While the Principals associated with the {@code Subject} are serialized,
91  * the credentials associated with the {@code Subject} are not.
92  * Note that the {@code java.security.Principal} class
93  * does not implement {@code Serializable}.  Therefore all concrete
94  * {@code Principal} implementations associated with Subjects
95  * must implement {@code Serializable}.
96  *
97  * @see java.security.Principal
98  * @see java.security.DomainCombiner
99  */
100 public final class Subject implements java.io.Serializable {
101 
102     private static final long serialVersionUID = -8308522755600156056L;
103 
104     /**
105      * A {@code Set} that provides a view of all of this
106      * Subject's Principals
107      *
108      * <p>
109      *
110      * @serial Each element in this set is a
111      *          {@code java.security.Principal}.
112      *          The set is a {@code Subject.SecureSet}.
113      */
114     Set<Principal> principals;
115 
116     /**
117      * Sets that provide a view of all of this
118      * Subject's Credentials
119      */
120     transient Set<Object> pubCredentials;
121     transient Set<Object> privCredentials;
122 
123     /**
124      * Whether this Subject is read-only
125      *
126      * @serial
127      */
128     private volatile boolean readOnly = false;
129 
130     private static final int PRINCIPAL_SET = 1;
131     private static final int PUB_CREDENTIAL_SET = 2;
132     private static final int PRIV_CREDENTIAL_SET = 3;
133 
134     private static final ProtectionDomain[] NULL_PD_ARRAY
135         = new ProtectionDomain[0];
136 
137     /**
138      * Create an instance of a {@code Subject}
139      * with an empty {@code Set} of Principals and empty
140      * Sets of public and private credentials.
141      *
142      * <p> The newly constructed Sets check whether this {@code Subject}
143      * has been set read-only before permitting subsequent modifications.
144      * The newly created Sets also prevent illegal modifications
145      * by ensuring that callers have sufficient permissions.
146      *
147      * <p> To modify the Principals Set, the caller must have
148      * {@code AuthPermission("modifyPrincipals")}.
149      * To modify the public credential Set, the caller must have
150      * {@code AuthPermission("modifyPublicCredentials")}.
151      * To modify the private credential Set, the caller must have
152      * {@code AuthPermission("modifyPrivateCredentials")}.
153      */
Subject()154     public Subject() {
155 
156         this.principals = Collections.synchronizedSet
157                         (new SecureSet<Principal>(this, PRINCIPAL_SET));
158         this.pubCredentials = Collections.synchronizedSet
159                         (new SecureSet<Object>(this, PUB_CREDENTIAL_SET));
160         this.privCredentials = Collections.synchronizedSet
161                         (new SecureSet<Object>(this, PRIV_CREDENTIAL_SET));
162     }
163 
164     /**
165      * Create an instance of a {@code Subject} with
166      * Principals and credentials.
167      *
168      * <p> The Principals and credentials from the specified Sets
169      * are copied into newly constructed Sets.
170      * These newly created Sets check whether this {@code Subject}
171      * has been set read-only before permitting subsequent modifications.
172      * The newly created Sets also prevent illegal modifications
173      * by ensuring that callers have sufficient permissions.
174      *
175      * <p> To modify the Principals Set, the caller must have
176      * {@code AuthPermission("modifyPrincipals")}.
177      * To modify the public credential Set, the caller must have
178      * {@code AuthPermission("modifyPublicCredentials")}.
179      * To modify the private credential Set, the caller must have
180      * {@code AuthPermission("modifyPrivateCredentials")}.
181      * <p>
182      *
183      * @param readOnly true if the {@code Subject} is to be read-only,
184      *          and false otherwise. <p>
185      *
186      * @param principals the {@code Set} of Principals
187      *          to be associated with this {@code Subject}. <p>
188      *
189      * @param pubCredentials the {@code Set} of public credentials
190      *          to be associated with this {@code Subject}. <p>
191      *
192      * @param privCredentials the {@code Set} of private credentials
193      *          to be associated with this {@code Subject}.
194      *
195      * @exception NullPointerException if the specified
196      *          {@code principals}, {@code pubCredentials},
197      *          or {@code privCredentials} are {@code null}.
198      */
Subject(boolean readOnly, Set<? extends Principal> principals, Set<?> pubCredentials, Set<?> privCredentials)199     public Subject(boolean readOnly, Set<? extends Principal> principals,
200                    Set<?> pubCredentials, Set<?> privCredentials)
201     {
202 
203         if (principals == null ||
204             pubCredentials == null ||
205             privCredentials == null)
206             throw new NullPointerException
207                 (ResourcesMgr.getString("invalid.null.input.s."));
208 
209         this.principals = Collections.synchronizedSet(new SecureSet<Principal>
210                                 (this, PRINCIPAL_SET, principals));
211         this.pubCredentials = Collections.synchronizedSet(new SecureSet<Object>
212                                 (this, PUB_CREDENTIAL_SET, pubCredentials));
213         this.privCredentials = Collections.synchronizedSet(new SecureSet<Object>
214                                 (this, PRIV_CREDENTIAL_SET, privCredentials));
215         this.readOnly = readOnly;
216     }
217 
218     /**
219      * Set this {@code Subject} to be read-only.
220      *
221      * <p> Modifications (additions and removals) to this Subject's
222      * {@code Principal} {@code Set} and
223      * credential Sets will be disallowed.
224      * The {@code destroy} operation on this Subject's credentials will
225      * still be permitted.
226      *
227      * <p> Subsequent attempts to modify the Subject's {@code Principal}
228      * and credential Sets will result in an
229      * {@code IllegalStateException} being thrown.
230      * Also, once a {@code Subject} is read-only,
231      * it can not be reset to being writable again.
232      *
233      * <p>
234      *
235      * @exception SecurityException if the caller does not have permission
236      *          to set this {@code Subject} to be read-only.
237      */
setReadOnly()238     public void setReadOnly() {
239         java.lang.SecurityManager sm = System.getSecurityManager();
240         if (sm != null) {
241             sm.checkPermission(AuthPermissionHolder.SET_READ_ONLY_PERMISSION);
242         }
243 
244         this.readOnly = true;
245     }
246 
247     /**
248      * Query whether this {@code Subject} is read-only.
249      *
250      * <p>
251      *
252      * @return true if this {@code Subject} is read-only, false otherwise.
253      */
isReadOnly()254     public boolean isReadOnly() {
255         return this.readOnly;
256     }
257 
258     /**
259      * Get the {@code Subject} associated with the provided
260      * {@code AccessControlContext}.
261      *
262      * <p> The {@code AccessControlContext} may contain many
263      * Subjects (from nested {@code doAs} calls).
264      * In this situation, the most recent {@code Subject} associated
265      * with the {@code AccessControlContext} is returned.
266      *
267      * <p>
268      *
269      * @param  acc the {@code AccessControlContext} from which to retrieve
270      *          the {@code Subject}.
271      *
272      * @return  the {@code Subject} associated with the provided
273      *          {@code AccessControlContext}, or {@code null}
274      *          if no {@code Subject} is associated
275      *          with the provided {@code AccessControlContext}.
276      *
277      * @exception SecurityException if the caller does not have permission
278      *          to get the {@code Subject}. <p>
279      *
280      * @exception NullPointerException if the provided
281      *          {@code AccessControlContext} is {@code null}.
282      */
getSubject(final AccessControlContext acc)283     public static Subject getSubject(final AccessControlContext acc) {
284 
285         java.lang.SecurityManager sm = System.getSecurityManager();
286         if (sm != null) {
287             sm.checkPermission(AuthPermissionHolder.GET_SUBJECT_PERMISSION);
288         }
289 
290         if (acc == null) {
291             throw new NullPointerException(ResourcesMgr.getString
292                 ("invalid.null.AccessControlContext.provided"));
293         }
294 
295         // return the Subject from the DomainCombiner of the provided context
296         return AccessController.doPrivileged
297             (new java.security.PrivilegedAction<Subject>() {
298             public Subject run() {
299                 DomainCombiner dc = acc.getDomainCombiner();
300                 if (!(dc instanceof SubjectDomainCombiner))
301                     return null;
302                 SubjectDomainCombiner sdc = (SubjectDomainCombiner)dc;
303                 return sdc.getSubject();
304             }
305         });
306     }
307 
308     /**
309      * Perform work as a particular {@code Subject}.
310      *
311      * <p> This method first retrieves the current Thread's
312      * {@code AccessControlContext} via
313      * {@code AccessController.getContext},
314      * and then instantiates a new {@code AccessControlContext}
315      * using the retrieved context along with a new
316      * {@code SubjectDomainCombiner} (constructed using
317      * the provided {@code Subject}).
318      * Finally, this method invokes {@code AccessController.doPrivileged},
319      * passing it the provided {@code PrivilegedAction},
320      * as well as the newly constructed {@code AccessControlContext}.
321      *
322      * <p>
323      *
324      * @param subject the {@code Subject} that the specified
325      *                  {@code action} will run as.  This parameter
326      *                  may be {@code null}. <p>
327      *
328      * @param <T> the type of the value returned by the PrivilegedAction's
329      *                  {@code run} method.
330      *
331      * @param action the code to be run as the specified
332      *                  {@code Subject}. <p>
333      *
334      * @return the value returned by the PrivilegedAction's
335      *                  {@code run} method.
336      *
337      * @exception NullPointerException if the {@code PrivilegedAction}
338      *                  is {@code null}. <p>
339      *
340      * @exception SecurityException if the caller does not have permission
341      *                  to invoke this method.
342      */
343     public static <T> T doAs(final Subject subject,
344                         final java.security.PrivilegedAction<T> action) {
345 
346         java.lang.SecurityManager sm = System.getSecurityManager();
347         if (sm != null) {
348             sm.checkPermission(AuthPermissionHolder.DO_AS_PERMISSION);
349         }
350         if (action == null)
351             throw new NullPointerException
352                 (ResourcesMgr.getString("invalid.null.action.provided"));
353 
354         // set up the new Subject-based AccessControlContext
355         // for doPrivileged
356         final AccessControlContext currentAcc = AccessController.getContext();
357 
358         // call doPrivileged and push this new context on the stack
359         return java.security.AccessController.doPrivileged
360                                         (action,
361                                         createContext(subject, currentAcc));
362     }
363 
364     /**
365      * Perform work as a particular {@code Subject}.
366      *
367      * <p> This method first retrieves the current Thread's
368      * {@code AccessControlContext} via
369      * {@code AccessController.getContext},
370      * and then instantiates a new {@code AccessControlContext}
371      * using the retrieved context along with a new
372      * {@code SubjectDomainCombiner} (constructed using
373      * the provided {@code Subject}).
374      * Finally, this method invokes {@code AccessController.doPrivileged},
375      * passing it the provided {@code PrivilegedExceptionAction},
376      * as well as the newly constructed {@code AccessControlContext}.
377      *
378      * <p>
379      *
380      * @param subject the {@code Subject} that the specified
381      *                  {@code action} will run as.  This parameter
382      *                  may be {@code null}. <p>
383      *
384      * @param <T> the type of the value returned by the
385      *                  PrivilegedExceptionAction's {@code run} method.
386      *
387      * @param action the code to be run as the specified
388      *                  {@code Subject}. <p>
389      *
390      * @return the value returned by the
391      *                  PrivilegedExceptionAction's {@code run} method.
392      *
393      * @exception PrivilegedActionException if the
394      *                  {@code PrivilegedExceptionAction.run}
395      *                  method throws a checked exception. <p>
396      *
397      * @exception NullPointerException if the specified
398      *                  {@code PrivilegedExceptionAction} is
399      *                  {@code null}. <p>
400      *
401      * @exception SecurityException if the caller does not have permission
402      *                  to invoke this method.
403      */
404     public static <T> T doAs(final Subject subject,
405                         final java.security.PrivilegedExceptionAction<T> action)
406                         throws java.security.PrivilegedActionException {
407 
408         java.lang.SecurityManager sm = System.getSecurityManager();
409         if (sm != null) {
410             sm.checkPermission(AuthPermissionHolder.DO_AS_PERMISSION);
411         }
412 
413         if (action == null)
414             throw new NullPointerException
415                 (ResourcesMgr.getString("invalid.null.action.provided"));
416 
417         // set up the new Subject-based AccessControlContext for doPrivileged
418         final AccessControlContext currentAcc = AccessController.getContext();
419 
420         // call doPrivileged and push this new context on the stack
421         return java.security.AccessController.doPrivileged
422                                         (action,
423                                         createContext(subject, currentAcc));
424     }
425 
426     /**
427      * Perform privileged work as a particular {@code Subject}.
428      *
429      * <p> This method behaves exactly as {@code Subject.doAs},
430      * except that instead of retrieving the current Thread's
431      * {@code AccessControlContext}, it uses the provided
432      * {@code AccessControlContext}.  If the provided
433      * {@code AccessControlContext} is {@code null},
434      * this method instantiates a new {@code AccessControlContext}
435      * with an empty collection of ProtectionDomains.
436      *
437      * <p>
438      *
439      * @param subject the {@code Subject} that the specified
440      *                  {@code action} will run as.  This parameter
441      *                  may be {@code null}. <p>
442      *
443      * @param <T> the type of the value returned by the PrivilegedAction's
444      *                  {@code run} method.
445      *
446      * @param action the code to be run as the specified
447      *                  {@code Subject}. <p>
448      *
449      * @param acc the {@code AccessControlContext} to be tied to the
450      *                  specified <i>subject</i> and <i>action</i>. <p>
451      *
452      * @return the value returned by the PrivilegedAction's
453      *                  {@code run} method.
454      *
455      * @exception NullPointerException if the {@code PrivilegedAction}
456      *                  is {@code null}. <p>
457      *
458      * @exception SecurityException if the caller does not have permission
459      *                  to invoke this method.
460      */
461     public static <T> T doAsPrivileged(final Subject subject,
462                         final java.security.PrivilegedAction<T> action,
463                         final java.security.AccessControlContext acc) {
464 
465         java.lang.SecurityManager sm = System.getSecurityManager();
466         if (sm != null) {
467             sm.checkPermission(AuthPermissionHolder.DO_AS_PRIVILEGED_PERMISSION);
468         }
469 
470         if (action == null)
471             throw new NullPointerException
472                 (ResourcesMgr.getString("invalid.null.action.provided"));
473 
474         // set up the new Subject-based AccessControlContext
475         // for doPrivileged
476         final AccessControlContext callerAcc =
477                 (acc == null ?
478                 new AccessControlContext(NULL_PD_ARRAY) :
479                 acc);
480 
481         // call doPrivileged and push this new context on the stack
482         return java.security.AccessController.doPrivileged
483                                         (action,
484                                         createContext(subject, callerAcc));
485     }
486 
487     /**
488      * Perform privileged work as a particular {@code Subject}.
489      *
490      * <p> This method behaves exactly as {@code Subject.doAs},
491      * except that instead of retrieving the current Thread's
492      * {@code AccessControlContext}, it uses the provided
493      * {@code AccessControlContext}.  If the provided
494      * {@code AccessControlContext} is {@code null},
495      * this method instantiates a new {@code AccessControlContext}
496      * with an empty collection of ProtectionDomains.
497      *
498      * <p>
499      *
500      * @param subject the {@code Subject} that the specified
501      *                  {@code action} will run as.  This parameter
502      *                  may be {@code null}. <p>
503      *
504      * @param <T> the type of the value returned by the
505      *                  PrivilegedExceptionAction's {@code run} method.
506      *
507      * @param action the code to be run as the specified
508      *                  {@code Subject}. <p>
509      *
510      * @param acc the {@code AccessControlContext} to be tied to the
511      *                  specified <i>subject</i> and <i>action</i>. <p>
512      *
513      * @return the value returned by the
514      *                  PrivilegedExceptionAction's {@code run} method.
515      *
516      * @exception PrivilegedActionException if the
517      *                  {@code PrivilegedExceptionAction.run}
518      *                  method throws a checked exception. <p>
519      *
520      * @exception NullPointerException if the specified
521      *                  {@code PrivilegedExceptionAction} is
522      *                  {@code null}. <p>
523      *
524      * @exception SecurityException if the caller does not have permission
525      *                  to invoke this method.
526      */
527     public static <T> T doAsPrivileged(final Subject subject,
528                         final java.security.PrivilegedExceptionAction<T> action,
529                         final java.security.AccessControlContext acc)
530                         throws java.security.PrivilegedActionException {
531 
532         java.lang.SecurityManager sm = System.getSecurityManager();
533         if (sm != null) {
534             sm.checkPermission(AuthPermissionHolder.DO_AS_PRIVILEGED_PERMISSION);
535         }
536 
537         if (action == null)
538             throw new NullPointerException
539                 (ResourcesMgr.getString("invalid.null.action.provided"));
540 
541         // set up the new Subject-based AccessControlContext for doPrivileged
542         final AccessControlContext callerAcc =
543                 (acc == null ?
544                 new AccessControlContext(NULL_PD_ARRAY) :
545                 acc);
546 
547         // call doPrivileged and push this new context on the stack
548         return java.security.AccessController.doPrivileged
549                                         (action,
550                                         createContext(subject, callerAcc));
551     }
552 
553     private static AccessControlContext createContext(final Subject subject,
554                                         final AccessControlContext acc) {
555 
556 
557         return java.security.AccessController.doPrivileged
558             (new java.security.PrivilegedAction<AccessControlContext>() {
559             public AccessControlContext run() {
560                 if (subject == null)
561                     return new AccessControlContext(acc, null);
562                 else
563                     return new AccessControlContext
564                                         (acc,
565                                         new SubjectDomainCombiner(subject));
566             }
567         });
568     }
569 
570     /**
571      * Return the {@code Set} of Principals associated with this
572      * {@code Subject}.  Each {@code Principal} represents
573      * an identity for this {@code Subject}.
574      *
575      * <p> The returned {@code Set} is backed by this Subject's
576      * internal {@code Principal} {@code Set}.  Any modification
577      * to the returned {@code Set} affects the internal
578      * {@code Principal} {@code Set} as well.
579      *
580      * <p>
581      *
582      * @return  The {@code Set} of Principals associated with this
583      *          {@code Subject}.
584      */
585     public Set<Principal> getPrincipals() {
586 
587         // always return an empty Set instead of null
588         // so LoginModules can add to the Set if necessary
589         return principals;
590     }
591 
592     /**
593      * Return a {@code Set} of Principals associated with this
594      * {@code Subject} that are instances or subclasses of the specified
595      * {@code Class}.
596      *
597      * <p> The returned {@code Set} is not backed by this Subject's
598      * internal {@code Principal} {@code Set}.  A new
599      * {@code Set} is created and returned for each method invocation.
600      * Modifications to the returned {@code Set}
601      * will not affect the internal {@code Principal} {@code Set}.
602      *
603      * <p>
604      *
605      * @param <T> the type of the class modeled by {@code c}
606      *
607      * @param c the returned {@code Set} of Principals will all be
608      *          instances of this class.
609      *
610      * @return a {@code Set} of Principals that are instances of the
611      *          specified {@code Class}.
612      *
613      * @exception NullPointerException if the specified {@code Class}
614      *                  is {@code null}.
615      */
616     public <T extends Principal> Set<T> getPrincipals(Class<T> c) {
617 
618         if (c == null)
619             throw new NullPointerException
620                 (ResourcesMgr.getString("invalid.null.Class.provided"));
621 
622         // always return an empty Set instead of null
623         // so LoginModules can add to the Set if necessary
624         return new ClassSet<T>(PRINCIPAL_SET, c);
625     }
626 
627     /**
628      * Return the {@code Set} of public credentials held by this
629      * {@code Subject}.
630      *
631      * <p> The returned {@code Set} is backed by this Subject's
632      * internal public Credential {@code Set}.  Any modification
633      * to the returned {@code Set} affects the internal public
634      * Credential {@code Set} as well.
635      *
636      * <p>
637      *
638      * @return  A {@code Set} of public credentials held by this
639      *          {@code Subject}.
640      */
641     public Set<Object> getPublicCredentials() {
642 
643         // always return an empty Set instead of null
644         // so LoginModules can add to the Set if necessary
645         return pubCredentials;
646     }
647 
648     /**
649      * Return the {@code Set} of private credentials held by this
650      * {@code Subject}.
651      *
652      * <p> The returned {@code Set} is backed by this Subject's
653      * internal private Credential {@code Set}.  Any modification
654      * to the returned {@code Set} affects the internal private
655      * Credential {@code Set} as well.
656      *
657      * <p> A caller requires permissions to access the Credentials
658      * in the returned {@code Set}, or to modify the
659      * {@code Set} itself.  A {@code SecurityException}
660      * is thrown if the caller does not have the proper permissions.
661      *
662      * <p> While iterating through the {@code Set},
663      * a {@code SecurityException} is thrown
664      * if the caller does not have permission to access a
665      * particular Credential.  The {@code Iterator}
666      * is nevertheless advanced to next element in the {@code Set}.
667      *
668      * <p>
669      *
670      * @return  A {@code Set} of private credentials held by this
671      *          {@code Subject}.
672      */
673     public Set<Object> getPrivateCredentials() {
674 
675         // XXX
676         // we do not need a security check for
677         // AuthPermission(getPrivateCredentials)
678         // because we already restrict access to private credentials
679         // via the PrivateCredentialPermission.  all the extra AuthPermission
680         // would do is protect the set operations themselves
681         // (like size()), which don't seem security-sensitive.
682 
683         // always return an empty Set instead of null
684         // so LoginModules can add to the Set if necessary
685         return privCredentials;
686     }
687 
688     /**
689      * Return a {@code Set} of public credentials associated with this
690      * {@code Subject} that are instances or subclasses of the specified
691      * {@code Class}.
692      *
693      * <p> The returned {@code Set} is not backed by this Subject's
694      * internal public Credential {@code Set}.  A new
695      * {@code Set} is created and returned for each method invocation.
696      * Modifications to the returned {@code Set}
697      * will not affect the internal public Credential {@code Set}.
698      *
699      * <p>
700      *
701      * @param <T> the type of the class modeled by {@code c}
702      *
703      * @param c the returned {@code Set} of public credentials will all be
704      *          instances of this class.
705      *
706      * @return a {@code Set} of public credentials that are instances
707      *          of the  specified {@code Class}.
708      *
709      * @exception NullPointerException if the specified {@code Class}
710      *          is {@code null}.
711      */
712     public <T> Set<T> getPublicCredentials(Class<T> c) {
713 
714         if (c == null)
715             throw new NullPointerException
716                 (ResourcesMgr.getString("invalid.null.Class.provided"));
717 
718         // always return an empty Set instead of null
719         // so LoginModules can add to the Set if necessary
720         return new ClassSet<T>(PUB_CREDENTIAL_SET, c);
721     }
722 
723     /**
724      * Return a {@code Set} of private credentials associated with this
725      * {@code Subject} that are instances or subclasses of the specified
726      * {@code Class}.
727      *
728      * <p> The caller must have permission to access all of the
729      * requested Credentials, or a {@code SecurityException}
730      * will be thrown.
731      *
732      * <p> The returned {@code Set} is not backed by this Subject's
733      * internal private Credential {@code Set}.  A new
734      * {@code Set} is created and returned for each method invocation.
735      * Modifications to the returned {@code Set}
736      * will not affect the internal private Credential {@code Set}.
737      *
738      * <p>
739      *
740      * @param <T> the type of the class modeled by {@code c}
741      *
742      * @param c the returned {@code Set} of private credentials will all be
743      *          instances of this class.
744      *
745      * @return a {@code Set} of private credentials that are instances
746      *          of the  specified {@code Class}.
747      *
748      * @exception NullPointerException if the specified {@code Class}
749      *          is {@code null}.
750      */
751     public <T> Set<T> getPrivateCredentials(Class<T> c) {
752 
753         // XXX
754         // we do not need a security check for
755         // AuthPermission(getPrivateCredentials)
756         // because we already restrict access to private credentials
757         // via the PrivateCredentialPermission.  all the extra AuthPermission
758         // would do is protect the set operations themselves
759         // (like size()), which don't seem security-sensitive.
760 
761         if (c == null)
762             throw new NullPointerException
763                 (ResourcesMgr.getString("invalid.null.Class.provided"));
764 
765         // always return an empty Set instead of null
766         // so LoginModules can add to the Set if necessary
767         return new ClassSet<T>(PRIV_CREDENTIAL_SET, c);
768     }
769 
770     /**
771      * Compares the specified Object with this {@code Subject}
772      * for equality.  Returns true if the given object is also a Subject
773      * and the two {@code Subject} instances are equivalent.
774      * More formally, two {@code Subject} instances are
775      * equal if their {@code Principal} and {@code Credential}
776      * Sets are equal.
777      *
778      * <p>
779      *
780      * @param o Object to be compared for equality with this
781      *          {@code Subject}.
782      *
783      * @return true if the specified Object is equal to this
784      *          {@code Subject}.
785      *
786      * @exception SecurityException if the caller does not have permission
787      *          to access the private credentials for this {@code Subject},
788      *          or if the caller does not have permission to access the
789      *          private credentials for the provided {@code Subject}.
790      */
791     public boolean equals(Object o) {
792 
793         if (o == null)
794             return false;
795 
796         if (this == o)
797             return true;
798 
799         if (o instanceof Subject) {
800 
801             final Subject that = (Subject)o;
802 
803             // check the principal and credential sets
804             Set<Principal> thatPrincipals;
805             synchronized(that.principals) {
806                 // avoid deadlock from dual locks
807                 thatPrincipals = new HashSet<Principal>(that.principals);
808             }
809             if (!principals.equals(thatPrincipals)) {
810                 return false;
811             }
812 
813             Set<Object> thatPubCredentials;
814             synchronized(that.pubCredentials) {
815                 // avoid deadlock from dual locks
816                 thatPubCredentials = new HashSet<Object>(that.pubCredentials);
817             }
818             if (!pubCredentials.equals(thatPubCredentials)) {
819                 return false;
820             }
821 
822             Set<Object> thatPrivCredentials;
823             synchronized(that.privCredentials) {
824                 // avoid deadlock from dual locks
825                 thatPrivCredentials = new HashSet<Object>(that.privCredentials);
826             }
827             if (!privCredentials.equals(thatPrivCredentials)) {
828                 return false;
829             }
830             return true;
831         }
832         return false;
833     }
834 
835     /**
836      * Return the String representation of this {@code Subject}.
837      *
838      * <p>
839      *
840      * @return the String representation of this {@code Subject}.
841      */
842     public String toString() {
843         return toString(true);
844     }
845 
846     /**
847      * package private convenience method to print out the Subject
848      * without firing off a security check when trying to access
849      * the Private Credentials
850      */
851     String toString(boolean includePrivateCredentials) {
852 
853         String s = ResourcesMgr.getString("Subject.");
854         String suffix = "";
855 
856         synchronized(principals) {
857             Iterator<Principal> pI = principals.iterator();
858             while (pI.hasNext()) {
859                 Principal p = pI.next();
860                 suffix = suffix + ResourcesMgr.getString(".Principal.") +
861                         p.toString() + ResourcesMgr.getString("NEWLINE");
862             }
863         }
864 
865         synchronized(pubCredentials) {
866             Iterator<Object> pI = pubCredentials.iterator();
867             while (pI.hasNext()) {
868                 Object o = pI.next();
869                 suffix = suffix +
870                         ResourcesMgr.getString(".Public.Credential.") +
871                         o.toString() + ResourcesMgr.getString("NEWLINE");
872             }
873         }
874 
875         if (includePrivateCredentials) {
876             synchronized(privCredentials) {
877                 Iterator<Object> pI = privCredentials.iterator();
878                 while (pI.hasNext()) {
879                     try {
880                         Object o = pI.next();
881                         suffix += ResourcesMgr.getString
882                                         (".Private.Credential.") +
883                                         o.toString() +
884                                         ResourcesMgr.getString("NEWLINE");
885                     } catch (SecurityException se) {
886                         suffix += ResourcesMgr.getString
887                                 (".Private.Credential.inaccessible.");
888                         break;
889                     }
890                 }
891             }
892         }
893         return s + suffix;
894     }
895 
896     /**
897      * Returns a hashcode for this {@code Subject}.
898      *
899      * <p>
900      *
901      * @return a hashcode for this {@code Subject}.
902      *
903      * @exception SecurityException if the caller does not have permission
904      *          to access this Subject's private credentials.
905      */
906     public int hashCode() {
907 
908         /**
909          * The hashcode is derived exclusive or-ing the
910          * hashcodes of this Subject's Principals and credentials.
911          *
912          * If a particular credential was destroyed
913          * ({@code credential.hashCode()} throws an
914          * {@code IllegalStateException}),
915          * the hashcode for that credential is derived via:
916          * {@code credential.getClass().toString().hashCode()}.
917          */
918 
919         int hashCode = 0;
920 
921         synchronized(principals) {
922             Iterator<Principal> pIterator = principals.iterator();
923             while (pIterator.hasNext()) {
924                 Principal p = pIterator.next();
925                 hashCode ^= p.hashCode();
926             }
927         }
928 
929         synchronized(pubCredentials) {
930             Iterator<Object> pubCIterator = pubCredentials.iterator();
931             while (pubCIterator.hasNext()) {
932                 hashCode ^= getCredHashCode(pubCIterator.next());
933             }
934         }
935         return hashCode;
936     }
937 
938     /**
939      * get a credential's hashcode
940      */
941     private int getCredHashCode(Object o) {
942         try {
943             return o.hashCode();
944         } catch (IllegalStateException ise) {
945             return o.getClass().toString().hashCode();
946         }
947     }
948 
949     /**
950      * Writes this object out to a stream (i.e., serializes it).
951      */
952     private void writeObject(java.io.ObjectOutputStream oos)
953                 throws java.io.IOException {
954         synchronized(principals) {
955             oos.defaultWriteObject();
956         }
957     }
958 
959     /**
960      * Reads this object from a stream (i.e., deserializes it)
961      */
962     @SuppressWarnings("unchecked")
963     private void readObject(java.io.ObjectInputStream s)
964                 throws java.io.IOException, ClassNotFoundException {
965 
966         ObjectInputStream.GetField gf = s.readFields();
967 
968         readOnly = gf.get("readOnly", false);
969 
970         Set<Principal> inputPrincs = (Set<Principal>)gf.get("principals", null);
971 
972         // Rewrap the principals into a SecureSet
973         if (inputPrincs == null) {
974             throw new NullPointerException
975                 (ResourcesMgr.getString("invalid.null.input.s."));
976         }
977         try {
978             principals = Collections.synchronizedSet(new SecureSet<Principal>
979                                 (this, PRINCIPAL_SET, inputPrincs));
980         } catch (NullPointerException npe) {
981             // Sometimes people deserialize the principals set only.
982             // Subject is not accessible, so just don't fail.
983             principals = Collections.synchronizedSet
984                         (new SecureSet<Principal>(this, PRINCIPAL_SET));
985         }
986 
987         // The Credential {@code Set} is not serialized, but we do not
988         // want the default deserialization routine to set it to null.
989         this.pubCredentials = Collections.synchronizedSet
990                         (new SecureSet<Object>(this, PUB_CREDENTIAL_SET));
991         this.privCredentials = Collections.synchronizedSet
992                         (new SecureSet<Object>(this, PRIV_CREDENTIAL_SET));
993     }
994 
995     /**
996      * Prevent modifications unless caller has permission.
997      *
998      * @serial include
999      */
1000     private static class SecureSet<E>
1001         extends AbstractSet<E>
1002         implements java.io.Serializable {
1003 
1004         private static final long serialVersionUID = 7911754171111800359L;
1005 
1006         /**
1007          * @serialField this$0 Subject The outer Subject instance.
1008          * @serialField elements LinkedList The elements in this set.
1009          */
1010         private static final ObjectStreamField[] serialPersistentFields = {
1011             new ObjectStreamField("this$0", Subject.class),
1012             new ObjectStreamField("elements", LinkedList.class),
1013             new ObjectStreamField("which", int.class)
1014         };
1015 
1016         Subject subject;
1017         LinkedList<E> elements;
1018 
1019         /**
1020          * @serial An integer identifying the type of objects contained
1021          *      in this set.  If {@code which == 1},
1022          *      this is a Principal set and all the elements are
1023          *      of type {@code java.security.Principal}.
1024          *      If {@code which == 2}, this is a public credential
1025          *      set and all the elements are of type {@code Object}.
1026          *      If {@code which == 3}, this is a private credential
1027          *      set and all the elements are of type {@code Object}.
1028          */
1029         private int which;
1030 
1031         SecureSet(Subject subject, int which) {
1032             this.subject = subject;
1033             this.which = which;
1034             this.elements = new LinkedList<E>();
1035         }
1036 
1037         SecureSet(Subject subject, int which, Set<? extends E> set) {
1038             this.subject = subject;
1039             this.which = which;
1040             this.elements = new LinkedList<E>(set);
1041         }
1042 
1043         public int size() {
1044             return elements.size();
1045         }
1046 
1047         public Iterator<E> iterator() {
1048             final LinkedList<E> list = elements;
1049             return new Iterator<E>() {
1050                 ListIterator<E> i = list.listIterator(0);
1051 
1052                 public boolean hasNext() {return i.hasNext();}
1053 
1054                 public E next() {
1055                     if (which != Subject.PRIV_CREDENTIAL_SET) {
1056                         return i.next();
1057                     }
1058 
1059                     SecurityManager sm = System.getSecurityManager();
1060                     if (sm != null) {
1061                         try {
1062                             sm.checkPermission(new PrivateCredentialPermission
1063                                 (list.get(i.nextIndex()).getClass().getName(),
1064                                 subject.getPrincipals()));
1065                         } catch (SecurityException se) {
1066                             i.next();
1067                             throw (se);
1068                         }
1069                     }
1070                     return i.next();
1071                 }
1072 
1073                 public void remove() {
1074 
1075                     if (subject.isReadOnly()) {
1076                         throw new IllegalStateException(ResourcesMgr.getString
1077                                 ("Subject.is.read.only"));
1078                     }
1079 
1080                     java.lang.SecurityManager sm = System.getSecurityManager();
1081                     if (sm != null) {
1082                         switch (which) {
1083                         case Subject.PRINCIPAL_SET:
1084                             sm.checkPermission(AuthPermissionHolder.MODIFY_PRINCIPALS_PERMISSION);
1085                             break;
1086                         case Subject.PUB_CREDENTIAL_SET:
1087                             sm.checkPermission(AuthPermissionHolder.MODIFY_PUBLIC_CREDENTIALS_PERMISSION);
1088                             break;
1089                         default:
1090                             sm.checkPermission(AuthPermissionHolder.MODIFY_PRIVATE_CREDENTIALS_PERMISSION);
1091                             break;
1092                         }
1093                     }
1094                     i.remove();
1095                 }
1096             };
1097         }
1098 
1099         public boolean add(E o) {
1100 
1101             if (subject.isReadOnly()) {
1102                 throw new IllegalStateException
1103                         (ResourcesMgr.getString("Subject.is.read.only"));
1104             }
1105 
1106             java.lang.SecurityManager sm = System.getSecurityManager();
1107             if (sm != null) {
1108                 switch (which) {
1109                 case Subject.PRINCIPAL_SET:
1110                     sm.checkPermission(AuthPermissionHolder.MODIFY_PRINCIPALS_PERMISSION);
1111                     break;
1112                 case Subject.PUB_CREDENTIAL_SET:
1113                     sm.checkPermission(AuthPermissionHolder.MODIFY_PUBLIC_CREDENTIALS_PERMISSION);
1114                     break;
1115                 default:
1116                     sm.checkPermission(AuthPermissionHolder.MODIFY_PRIVATE_CREDENTIALS_PERMISSION);
1117                     break;
1118                 }
1119             }
1120 
1121             switch (which) {
1122             case Subject.PRINCIPAL_SET:
1123                 if (!(o instanceof Principal)) {
1124                     throw new SecurityException(ResourcesMgr.getString
1125                         ("attempting.to.add.an.object.which.is.not.an.instance.of.java.security.Principal.to.a.Subject.s.Principal.Set"));
1126                 }
1127                 break;
1128             default:
1129                 // ok to add Objects of any kind to credential sets
1130                 break;
1131             }
1132 
1133             // check for duplicates
1134             if (!elements.contains(o))
1135                 return elements.add(o);
1136             else
1137                 return false;
1138         }
1139 
1140         public boolean remove(Object o) {
1141 
1142             final Iterator<E> e = iterator();
1143             while (e.hasNext()) {
1144                 E next;
1145                 if (which != Subject.PRIV_CREDENTIAL_SET) {
1146                     next = e.next();
1147                 } else {
1148                     next = java.security.AccessController.doPrivileged
1149                         (new java.security.PrivilegedAction<E>() {
1150                         public E run() {
1151                             return e.next();
1152                         }
1153                     });
1154                 }
1155 
1156                 if (next == null) {
1157                     if (o == null) {
1158                         e.remove();
1159                         return true;
1160                     }
1161                 } else if (next.equals(o)) {
1162                     e.remove();
1163                     return true;
1164                 }
1165             }
1166             return false;
1167         }
1168 
1169         public boolean contains(Object o) {
1170             final Iterator<E> e = iterator();
1171             while (e.hasNext()) {
1172                 E next;
1173                 if (which != Subject.PRIV_CREDENTIAL_SET) {
1174                     next = e.next();
1175                 } else {
1176 
1177                     // For private credentials:
1178                     // If the caller does not have read permission for
1179                     // for o.getClass(), we throw a SecurityException.
1180                     // Otherwise we check the private cred set to see whether
1181                     // it contains the Object
1182 
1183                     SecurityManager sm = System.getSecurityManager();
1184                     if (sm != null) {
1185                         sm.checkPermission(new PrivateCredentialPermission
1186                                                 (o.getClass().getName(),
1187                                                 subject.getPrincipals()));
1188                     }
1189                     next = java.security.AccessController.doPrivileged
1190                         (new java.security.PrivilegedAction<E>() {
1191                         public E run() {
1192                             return e.next();
1193                         }
1194                     });
1195                 }
1196 
1197                 if (next == null) {
1198                     if (o == null) {
1199                         return true;
1200                     }
1201                 } else if (next.equals(o)) {
1202                     return true;
1203                 }
1204             }
1205             return false;
1206         }
1207 
1208         public boolean removeAll(Collection<?> c) {
1209             Objects.requireNonNull(c);
1210             boolean modified = false;
1211             final Iterator<E> e = iterator();
1212             while (e.hasNext()) {
1213                 E next;
1214                 if (which != Subject.PRIV_CREDENTIAL_SET) {
1215                     next = e.next();
1216                 } else {
1217                     next = java.security.AccessController.doPrivileged
1218                         (new java.security.PrivilegedAction<E>() {
1219                         public E run() {
1220                             return e.next();
1221                         }
1222                     });
1223                 }
1224 
1225                 Iterator<?> ce = c.iterator();
1226                 while (ce.hasNext()) {
1227                     Object o = ce.next();
1228                     if (next == null) {
1229                         if (o == null) {
1230                             e.remove();
1231                             modified = true;
1232                             break;
1233                         }
1234                     } else if (next.equals(o)) {
1235                         e.remove();
1236                         modified = true;
1237                         break;
1238                     }
1239                 }
1240             }
1241             return modified;
1242         }
1243 
1244         public boolean retainAll(Collection<?> c) {
1245             Objects.requireNonNull(c);
1246             boolean modified = false;
1247             boolean retain = false;
1248             final Iterator<E> e = iterator();
1249             while (e.hasNext()) {
1250                 retain = false;
1251                 E next;
1252                 if (which != Subject.PRIV_CREDENTIAL_SET) {
1253                     next = e.next();
1254                 } else {
1255                     next = java.security.AccessController.doPrivileged
1256                         (new java.security.PrivilegedAction<E>() {
1257                         public E run() {
1258                             return e.next();
1259                         }
1260                     });
1261                 }
1262 
1263                 Iterator<?> ce = c.iterator();
1264                 while (ce.hasNext()) {
1265                     Object o = ce.next();
1266                     if (next == null) {
1267                         if (o == null) {
1268                             retain = true;
1269                             break;
1270                         }
1271                     } else if (next.equals(o)) {
1272                         retain = true;
1273                         break;
1274                     }
1275                 }
1276 
1277                 if (!retain) {
1278                     e.remove();
1279                     retain = false;
1280                     modified = true;
1281                 }
1282             }
1283             return modified;
1284         }
1285 
1286         public void clear() {
1287             final Iterator<E> e = iterator();
1288             while (e.hasNext()) {
1289                 E next;
1290                 if (which != Subject.PRIV_CREDENTIAL_SET) {
1291                     next = e.next();
1292                 } else {
1293                     next = java.security.AccessController.doPrivileged
1294                         (new java.security.PrivilegedAction<E>() {
1295                         public E run() {
1296                             return e.next();
1297                         }
1298                     });
1299                 }
1300                 e.remove();
1301             }
1302         }
1303 
1304         /**
1305          * Writes this object out to a stream (i.e., serializes it).
1306          *
1307          * <p>
1308          *
1309          * @serialData If this is a private credential set,
1310          *      a security check is performed to ensure that
1311          *      the caller has permission to access each credential
1312          *      in the set.  If the security check passes,
1313          *      the set is serialized.
1314          */
1315         private void writeObject(java.io.ObjectOutputStream oos)
1316                 throws java.io.IOException {
1317 
1318             if (which == Subject.PRIV_CREDENTIAL_SET) {
1319                 // check permissions before serializing
1320                 Iterator<E> i = iterator();
1321                 while (i.hasNext()) {
1322                     i.next();
1323                 }
1324             }
1325             ObjectOutputStream.PutField fields = oos.putFields();
1326             fields.put("this$0", subject);
1327             fields.put("elements", elements);
1328             fields.put("which", which);
1329             oos.writeFields();
1330         }
1331 
1332         @SuppressWarnings("unchecked")
1333         private void readObject(ObjectInputStream ois)
1334             throws IOException, ClassNotFoundException
1335         {
1336             ObjectInputStream.GetField fields = ois.readFields();
1337             subject = (Subject) fields.get("this$0", null);
1338             which = fields.get("which", 0);
1339 
1340             LinkedList<E> tmp = (LinkedList<E>) fields.get("elements", null);
1341             if (tmp.getClass() != LinkedList.class) {
1342                 elements = new LinkedList<E>(tmp);
1343             } else {
1344                 elements = tmp;
1345             }
1346         }
1347     }
1348 
1349     /**
1350      * This class implements a {@code Set} which returns only
1351      * members that are an instance of a specified Class.
1352      */
1353     private class ClassSet<T> extends AbstractSet<T> {
1354 
1355         private int which;
1356         private Class<T> c;
1357         private Set<T> set;
1358 
1359         ClassSet(int which, Class<T> c) {
1360             this.which = which;
1361             this.c = c;
1362             set = new HashSet<T>();
1363 
1364             switch (which) {
1365             case Subject.PRINCIPAL_SET:
1366                 synchronized(principals) { populateSet(); }
1367                 break;
1368             case Subject.PUB_CREDENTIAL_SET:
1369                 synchronized(pubCredentials) { populateSet(); }
1370                 break;
1371             default:
1372                 synchronized(privCredentials) { populateSet(); }
1373                 break;
1374             }
1375         }
1376 
1377         @SuppressWarnings("unchecked")     /*To suppress warning from line 1374*/
1378         private void populateSet() {
1379             final Iterator<?> iterator;
1380             switch(which) {
1381             case Subject.PRINCIPAL_SET:
1382                 iterator = Subject.this.principals.iterator();
1383                 break;
1384             case Subject.PUB_CREDENTIAL_SET:
1385                 iterator = Subject.this.pubCredentials.iterator();
1386                 break;
1387             default:
1388                 iterator = Subject.this.privCredentials.iterator();
1389                 break;
1390             }
1391 
1392             // Check whether the caller has permisson to get
1393             // credentials of Class c
1394 
1395             while (iterator.hasNext()) {
1396                 Object next;
1397                 if (which == Subject.PRIV_CREDENTIAL_SET) {
1398                     next = java.security.AccessController.doPrivileged
1399                         (new java.security.PrivilegedAction<Object>() {
1400                         public Object run() {
1401                             return iterator.next();
1402                         }
1403                     });
1404                 } else {
1405                     next = iterator.next();
1406                 }
1407                 if (c.isAssignableFrom(next.getClass())) {
1408                     if (which != Subject.PRIV_CREDENTIAL_SET) {
1409                         set.add((T)next);
1410                     } else {
1411                         // Check permission for private creds
1412                         SecurityManager sm = System.getSecurityManager();
1413                         if (sm != null) {
1414                             sm.checkPermission(new PrivateCredentialPermission
1415                                                 (next.getClass().getName(),
1416                                                 Subject.this.getPrincipals()));
1417                         }
1418                         set.add((T)next);
1419                     }
1420                 }
1421             }
1422         }
1423 
1424         public int size() {
1425             return set.size();
1426         }
1427 
1428         public Iterator<T> iterator() {
1429             return set.iterator();
1430         }
1431 
1432         public boolean add(T o) {
1433 
1434             if (!o.getClass().isAssignableFrom(c)) {
1435                 MessageFormat form = new MessageFormat(ResourcesMgr.getString
1436                         ("attempting.to.add.an.object.which.is.not.an.instance.of.class"));
1437                 Object[] source = {c.toString()};
1438                 throw new SecurityException(form.format(source));
1439             }
1440 
1441             return set.add(o);
1442         }
1443     }
1444 
1445     static class AuthPermissionHolder {
1446         static final AuthPermission DO_AS_PERMISSION =
1447             new AuthPermission("doAs");
1448 
1449         static final AuthPermission DO_AS_PRIVILEGED_PERMISSION =
1450             new AuthPermission("doAsPrivileged");
1451 
1452         static final AuthPermission SET_READ_ONLY_PERMISSION =
1453             new AuthPermission("setReadOnly");
1454 
1455         static final AuthPermission GET_SUBJECT_PERMISSION =
1456             new AuthPermission("getSubject");
1457 
1458         static final AuthPermission MODIFY_PRINCIPALS_PERMISSION =
1459             new AuthPermission("modifyPrincipals");
1460 
1461         static final AuthPermission MODIFY_PUBLIC_CREDENTIALS_PERMISSION =
1462             new AuthPermission("modifyPublicCredentials");
1463 
1464         static final AuthPermission MODIFY_PRIVATE_CREDENTIALS_PERMISSION =
1465             new AuthPermission("modifyPrivateCredentials");
1466     }
1467 }
1468