mcs/class/corlib/System.Security/PermissionSet.cs

   1 //
   2 // System.Security.PermissionSet.cs
   3 //
   4 // Authors:
   5 //      Nick Drochak(ndrochak@gol.com)
   6 //      Sebastien Pouliot  <sebastien@ximian.com>
   7 //
   8 // (C) Nick Drochak
   9 // Portions (C) 2003, 2004 Motus Technologies Inc. (http://www.motus.com)
  10 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Collections;
  33 using System.Diagnostics;
  34 using System.IO;
  35 using System.Reflection;
  36 using System.Runtime.InteropServices;
  37 using System.Runtime.Serialization;
  38 using System.Runtime.Serialization.Formatters.Binary;
  39 using System.Security.Permissions;
  40 using System.Security.Policy;
  41 using System.Text;
  42 using System.Threading;
  43
  44 namespace System.Security {
  45
  46         [Serializable]
  47         // Microsoft public key - i.e. only MS signed assembly can inherit from PermissionSet (1.x) or (2.0) FullTrust assemblies
  48         [StrongNameIdentityPermission (SecurityAction.InheritanceDemand, PublicKey="002400000480000094000000060200000024000052534131000400000100010007D1FA57C4AED9F0A32E84AA0FAEFD0DE9E8FD6AEC8F87FB03766C834C99921EB23BE79AD9D5DCC1DD9AD236132102900B723CF980957FC4E177108FC607774F29E8320E92EA05ECE4E821C0A5EFE8F1645C4C0C93C1AB99285D622CAA652C1DFAD63D745D6F2DE5F17E5EAF0FC4963D261C8A12436518206DC093344D5AD293")]
  49 #if NET_2_0
  50         [ComVisible (true)]
  51 #endif
  52         public class PermissionSet: ISecurityEncodable, ICollection, IEnumerable, IStackWalk, IDeserializationCallback {
  53
  54                 private const string tagName = "PermissionSet";
  55                 private const int version = 1;
  56                 private static object[] psUnrestricted = new object [1] { PermissionState.Unrestricted };
  57
  58                 private PermissionState state;
  59                 private ArrayList list;
  60                 private int _hashcode;
  61                 private PolicyLevel _policyLevel;
  62                 private bool _declsec;
  63                 private bool _readOnly;
  64                 private bool[] _ignored; // for asserts and non-CAS permissions
  65
  66                 // constructors
  67
  68                 // for PolicyLevel (to avoid validation duplication)
  69                 internal PermissionSet ()
  70                 {
  71                         list = new ArrayList ();
  72                 }
  73
  74                 public PermissionSet (PermissionState state) : this ()
  75                 {
  76                         this.state = CodeAccessPermission.CheckPermissionState (state, true);
  77                 }
  78
  79                 public PermissionSet (PermissionSet permSet) : this ()
  80                 {
  81                         // LAMESPEC: This would be handled by the compiler.  No way permSet is not a PermissionSet.
  82                         //if (!(permSet is PermissionSet))
  83                         //      throw new System.ArgumentException(); // permSet is not an instance of System.Security.PermissionSet.
  84                         if (permSet != null) {
  85                                 state = permSet.state;
  86                                 foreach (IPermission p in permSet.list)
  87                                         list.Add (p);
  88                         }
  89 #if !NET_2_0
  90                         else {
  91                                 state = PermissionState.Unrestricted;
  92                         }
  93 #endif
  94                 }
  95
  96                 internal PermissionSet (string xml)
  97                         : this ()
  98                 {
  99                         state = PermissionState.None;
 100                         if (xml != null) {
 101                                 SecurityElement se = SecurityElement.FromString (xml);
 102                                 FromXml (se);
 103                         }
 104                 }
 105
 106                 // Light version for creating a (non unrestricted) PermissionSet with
 107                 // a single permission. This allows to relax most validations.
 108                 internal PermissionSet (IPermission perm)
 109                         : this ()
 110                 {
 111                         if (perm != null) {
 112                                 // note: we do not copy IPermission like AddPermission
 113                                 list.Add (perm);
 114                         }
 115                 }
 116
 117                 // methods
 118
 119 #if NET_2_0
 120                 public IPermission AddPermission (IPermission perm)
 121 #else
 122                 public virtual IPermission AddPermission (IPermission perm)
 123 #endif
 124                 {
 125                         if ((perm == null) || _readOnly)
 126                                 return perm;
 127
 128                         // we don't add to an unrestricted permission set unless...
 129                         if (state == PermissionState.Unrestricted) {
 130 #if NET_2_0
 131                                 // identity permissions can be unrestricted under 2.x
 132                                 {
 133 #else
 134                                 // we're adding identity permission as they don't support unrestricted
 135                                 if (perm is IUnrestrictedPermission) {
 136 #endif
 137                                         // we return the union of the permission with unrestricted
 138                                         // which results in a permission of the same type initialized
 139                                         // with PermissionState.Unrestricted
 140                                         return (IPermission) Activator.CreateInstance (perm.GetType (), psUnrestricted);
 141                                 }
 142                         }
 143
 144                         // we can't add two permissions of the same type in a set
 145                         // so we remove an existing one, union with it and add it back
 146                         IPermission existing = RemovePermission (perm.GetType ());
 147                         if (existing != null) {
 148                                 perm = perm.Union (existing);
 149                         }
 150
 151                         // note: Add doesn't copy
 152                         list.Add (perm);
 153                         return perm;
 154                 }
 155
 156                 [MonoTODO ("Imperative mode isn't supported")]
 157                 [SecurityPermission (SecurityAction.Demand, Assertion = true)]
 158 #if NET_2_0
 159                 public void Assert ()
 160 #else
 161                 public virtual void Assert ()
 162 #endif
 163                 {
 164                         int count = this.Count;
 165
 166                         // we (current frame) must have the permission to assert it to others
 167                         // otherwise we don't assert (but we don't throw an exception)
 168                         foreach (IPermission p in list) {
 169                                 // note: we ignore non-CAS permissions
 170                                 if (p is IStackWalk) {
 171                                         if (!SecurityManager.IsGranted (p)) {
 172                                                 return;
 173                                         }
 174                                 } else
 175                                         count--;
 176                         }
 177
 178                         // note: we must ignore the stack modifiers for the non-CAS permissions
 179                         if (SecurityManager.SecurityEnabled && (count > 0))
 180                                 throw new NotSupportedException ("Currently only declarative Assert are supported.");
 181                 }
 182
 183                 internal void Clear ()
 184                 {
 185                         list.Clear ();
 186                 }
 187
 188                 public virtual PermissionSet Copy ()
 189                 {
 190                         return new PermissionSet (this);
 191                 }
 192
 193                 public virtual void CopyTo (Array array, int index)
 194                 {
 195                         if (null == array)
 196                                 throw new ArgumentNullException ("array");
 197
 198                         if (list.Count > 0) {
 199                                 if (array.Rank > 1) {
 200                                         throw new ArgumentException (Locale.GetText (
 201                                                 "Array has more than one dimension"));
 202                                 }
 203                                 if (index < 0 || index >= array.Length) {
 204                                         throw new IndexOutOfRangeException ("index");
 205                                 }
 206
 207                                 list.CopyTo (array, index);
 208                         }
 209                 }
 210
 211 #if NET_2_0
 212                 public void Demand ()
 213 #else
 214                 public virtual void Demand ()
 215 #endif
 216                 {
 217                         // Note: SecurityEnabled only applies to CAS permissions
 218                         // so we're not checking for it (yet)
 219                         if (IsEmpty ())
 220                                 return;
 221
 222                         int n = list.Count;
 223                         if ((_ignored == null) || (_ignored.Length != n)) {
 224                                 _ignored = new bool [n];
 225                         }
 226
 227                         bool call_cas_only = this.IsUnrestricted ();
 228                         // non CAS permissions (e.g. PrincipalPermission) do not requires a stack walk
 229                         for (int i = 0; i < n; i++) {
 230                                 CodeAccessPermission p = (CodeAccessPermission) list [i];
 231                                 Type t = p.GetType ();
 232                                 if (t.IsSubclassOf (typeof (CodeAccessPermission))) {
 233                                         _ignored [i] = false;
 234                                         call_cas_only = true;
 235                                 } else {
 236                                         _ignored [i] = true;
 237                                         p.Demand ();
 238                                 }
 239                         }
 240
 241                         // don't start the stack walk if
 242                         // - the permission set only contains non CAS permissions; or
 243                         // - security isn't enabled (applis only to CAS!)
 244                         if (call_cas_only && SecurityManager.SecurityEnabled)
 245                                 CasOnlyDemand (_declsec ? 5 : 3);
 246                 }
 247
 248                 // The number of frames to skip depends on who's calling
 249                 // - CodeAccessPermission.Demand (imperative)
 250                 // - PermissionSet.Demand (imperative)
 251                 // - SecurityManager.InternalDemand (declarative)
 252                 internal void CasOnlyDemand (int skip)
 253                 {
 254                         Assembly current = null;
 255                         AppDomain domain = null;
 256
 257                         if (_ignored == null) {
 258                                 // special case when directly called from CodeAccessPermission.Demand
 259                                 _ignored = new bool [list.Count];
 260                         }
 261
 262                         ArrayList frames = SecurityFrame.GetStack (skip);
 263                         if ((frames != null) && (frames.Count > 0)) {
 264                                 SecurityFrame first = ((SecurityFrame) frames [0]);
 265                                 current = first.Assembly;
 266                                 domain = first.Domain;
 267                                 // skip ourself, Demand and other security runtime methods
 268                                 foreach (SecurityFrame sf in frames) {
 269                                         if (ProcessFrame (sf, ref current, ref domain)) {
 270                                                 if (AllIgnored ())
 271                                                         return; // reached Assert
 272                                         }
 273                                 }
 274                                 SecurityFrame last = ((SecurityFrame) frames [frames.Count - 1]);
 275                                 CheckAssembly (current, last);
 276                                 CheckAppDomain (domain, last);
 277                         }
 278
 279                         // Is there a CompressedStack to handle ?
 280                         CompressedStack stack = Thread.CurrentThread.GetCompressedStack ();
 281                         if ((stack != null) && !stack.IsEmpty ()) {
 282                                 foreach (SecurityFrame frame in stack.List) {
 283                                         if (ProcessFrame (frame, ref current, ref domain)) {
 284                                                 if (AllIgnored ())
 285                                                         return; // reached Assert
 286                                         }
 287                                 }
 288                         }
 289                 }
 290
 291                 [MonoTODO ("Imperative mode isn't supported")]
 292 #if NET_2_0
 293                 public void Deny ()
 294 #else
 295                 public virtual void Deny ()
 296 #endif
 297                 {
 298                         if (!SecurityManager.SecurityEnabled)
 299                                 return;
 300
 301                         foreach (IPermission p in list) {
 302                                 // note: we ignore non-CAS permissions
 303                                 if (p is IStackWalk) {
 304                                         throw new NotSupportedException ("Currently only declarative Deny are supported.");
 305                                 }
 306                         }
 307                 }
 308
 309                 public virtual void FromXml (SecurityElement et)
 310                 {
 311                         if (et == null)
 312                                 throw new ArgumentNullException ("et");
 313                         if (et.Tag != tagName) {
 314                                 string msg = String.Format ("Invalid tag {0} expected {1}", et.Tag, tagName);
 315                                 throw new ArgumentException (msg, "et");
 316                         }
 317
 318                         list.Clear ();
 319
 320                         if (CodeAccessPermission.IsUnrestricted (et)) {
 321                                 state = PermissionState.Unrestricted;
 322 #if NET_2_0
 323                                 // no need to continue for an unrestricted permission
 324                                 // because identity permissions now "supports" unrestricted
 325                                 return;
 326 #endif
 327                         } else {
 328                                 state = PermissionState.None;
 329                         }
 330
 331                         if (et.Children != null) {
 332                                 foreach (SecurityElement se in et.Children) {
 333                                         string className = se.Attribute ("class");
 334                                         if (className == null) {
 335                                                 throw new ArgumentException (Locale.GetText (
 336                                                         "No permission class is specified."));
 337                                         }
 338                                         if (Resolver != null) {
 339                                                 // policy class names do not have to be fully qualified
 340                                                 className = Resolver.ResolveClassName (className);
 341                                         }
 342
 343                                         list.Add (PermissionBuilder.Create (className, se));
 344                                 }
 345                         }
 346                 }
 347
 348 #if NET_2_0
 349                 public IEnumerator GetEnumerator ()
 350 #else
 351                 public virtual IEnumerator GetEnumerator ()
 352 #endif
 353                 {
 354                         return list.GetEnumerator ();
 355                 }
 356
 357 #if NET_2_0
 358                 public bool IsSubsetOf (PermissionSet target)
 359                 {
 360                         // if target is empty we must be empty too
 361                         if ((target == null) || (target.IsEmpty ()))
 362                                 return this.IsEmpty ();
 363
 364                         // all permissions support unrestricted in 2.0
 365                         if (target.IsUnrestricted ())
 366                                 return true;
 367                         if (this.IsUnrestricted ())
 368                                 return false;
 369 #else
 370                 public virtual bool IsSubsetOf (PermissionSet target)
 371                 {
 372 #endif
 373                         if (this.IsUnrestricted () && ((target == null) || !target.IsUnrestricted ()))
 374                                 return false;
 375
 376                         // if each of our permission is (a) present and (b) a subset of target
 377                         foreach (IPermission p in list) {
 378 #if !NET_2_0
 379                                 if (target == null) {
 380                                         if (!p.IsSubsetOf (null))
 381                                                 return false;
 382                                 } else
 383 #endif
 384                                 {
 385                                         // non CAS permissions must be evaluated for unrestricted
 386                                         Type t = p.GetType ();
 387                                         IPermission i = null;
 388                                         if (target.IsUnrestricted () && (p is CodeAccessPermission) && (p is IUnrestrictedPermission)) {
 389                                                 i = (IPermission) Activator.CreateInstance (t, psUnrestricted);
 390                                         } else {
 391                                                 i = target.GetPermission (t);
 392                                         }
 393
 394                                         if (!p.IsSubsetOf (i))
 395                                                 return false; // not a subset (condition b)
 396                                 }
 397                         }
 398                         return true;
 399                 }
 400
 401                 [MonoTODO ("Imperative mode isn't supported")]
 402 #if NET_2_0
 403                 public void PermitOnly ()
 404 #else
 405                 public virtual void PermitOnly ()
 406 #endif
 407                 {
 408                         if (!SecurityManager.SecurityEnabled)
 409                                 return;
 410
 411                         foreach (IPermission p in list) {
 412                                 // note: we ignore non-CAS permissions
 413                                 if (p is IStackWalk) {
 414                                         throw new NotSupportedException ("Currently only declarative Deny are supported.");
 415                                 }
 416                         }
 417                 }
 418
 419                 public bool ContainsNonCodeAccessPermissions ()
 420                 {
 421                         if (list.Count > 0) {
 422                                 foreach (IPermission p in list) {
 423                                         if (! p.GetType ().IsSubclassOf (typeof (CodeAccessPermission)))
 424                                                 return true;
 425                                 }
 426                         }
 427                         return false;
 428                 }
 429
 430                 [MonoTODO ("little documentation in Fx 2.0 beta 1")]
 431                 public static byte[] ConvertPermissionSet (string inFormat, byte[] inData, string outFormat)
 432                 {
 433                         if (inFormat == null)
 434                                 throw new ArgumentNullException ("inFormat");
 435                         if (outFormat == null)
 436                                 throw new ArgumentNullException ("outFormat");
 437                         if (inData == null)
 438                                 return null;
 439
 440                         if (inFormat == outFormat)
 441                                 return inData;
 442
 443                         PermissionSet ps = null;
 444
 445                         if (inFormat == "BINARY") {
 446                                 if (outFormat.StartsWith ("XML")) {
 447                                         using (MemoryStream ms = new MemoryStream (inData)) {
 448                                                 BinaryFormatter formatter = new BinaryFormatter ();
 449                                                 ps = (PermissionSet) formatter.Deserialize (ms);
 450                                                 ms.Close ();
 451                                         }
 452                                         string xml = ps.ToString ();
 453                                         switch (outFormat) {
 454                                                 case "XML":
 455                                                 case "XMLASCII":
 456                                                         return Encoding.ASCII.GetBytes (xml);
 457                                                 case "XMLUNICODE":
 458                                                         return Encoding.Unicode.GetBytes (xml);
 459                                         }
 460                                 }
 461                         }
 462                         else if (inFormat.StartsWith ("XML")) {
 463                                 if (outFormat == "BINARY") {
 464                                         string xml = null;
 465                                         switch (inFormat) {
 466                                                 case "XML":
 467                                                 case "XMLASCII":
 468                                                         xml = Encoding.ASCII.GetString (inData);
 469                                                         break;
 470                                                 case "XMLUNICODE":
 471                                                         xml = Encoding.Unicode.GetString (inData);
 472                                                         break;
 473                                         }
 474                                         if (xml != null) {
 475                                                 ps = new PermissionSet (PermissionState.None);
 476                                                 ps.FromXml (SecurityElement.FromString (xml));
 477
 478                                                 MemoryStream ms = new MemoryStream ();
 479                                                 BinaryFormatter formatter = new BinaryFormatter ();
 480                                                 formatter.Serialize (ms, ps);
 481                                                 ms.Close ();
 482                                                 return ms.ToArray ();
 483                                         }
 484                                 }
 485                                 else if (outFormat.StartsWith ("XML")) {
 486                                         string msg = String.Format (Locale.GetText ("Can't convert from {0} to {1}"), inFormat, outFormat);
 487 #if NET_2_0
 488                                         throw new XmlSyntaxException (msg);
 489 #else
 490                                         throw new ArgumentException (msg);
 491 #endif
 492                                 }
 493                         }
 494                         else {
 495                                 // unknown inFormat, returns null
 496                                 return null;
 497                         }
 498                         // unknown outFormat, throw
 499                         throw new SerializationException (String.Format (Locale.GetText ("Unknown output format {0}."), outFormat));
 500                 }
 501
 502 #if NET_2_0
 503                 public IPermission GetPermission (Type permClass)
 504 #else
 505                 public virtual IPermission GetPermission (Type permClass)
 506 #endif
 507                 {
 508                         if ((permClass == null) || (list.Count == 0))
 509                                 return null;
 510
 511                         foreach (object o in list) {
 512                                 if ((o != null) && o.GetType ().Equals (permClass))
 513                                         return (IPermission) o;
 514                         }
 515                         // it's normal to return null for unrestricted sets
 516                         return null;
 517                 }
 518
 519 #if NET_2_0
 520                 public PermissionSet Intersect (PermissionSet other)
 521 #else
 522                 public virtual PermissionSet Intersect (PermissionSet other)
 523 #endif
 524                 {
 525                         // no intersection possible
 526                         if ((other == null) || (other.IsEmpty ()) || (this.IsEmpty ()))
 527                                 return null;
 528
 529                         PermissionState state = PermissionState.None;
 530                         if (this.IsUnrestricted () && other.IsUnrestricted ())
 531                                 state = PermissionState.Unrestricted;
 532
 533                         PermissionSet interSet = null;
 534 #if NET_2_0
 535                         // much simpler with 2.0
 536                         if (state == PermissionState.Unrestricted) {
 537                                 interSet = new PermissionSet (state);
 538                         } else if (this.IsUnrestricted ()) {
 539                                 interSet = other.Copy ();
 540                         } else if (other.IsUnrestricted ()) {
 541                                 interSet = this.Copy ();
 542                         } else {
 543                                 interSet = new PermissionSet (state);
 544                                 InternalIntersect (interSet, this, other, false);
 545                         }
 546 #else
 547                         interSet = new PermissionSet (state);
 548                         if (state == PermissionState.Unrestricted) {
 549                                 InternalIntersect (interSet, this, other, true);
 550                                 InternalIntersect (interSet, other, this, true);
 551                         } else if (this.IsUnrestricted ()) {
 552                                 InternalIntersect (interSet, this, other, true);
 553                         } else if (other.IsUnrestricted ()) {
 554                                 InternalIntersect (interSet, other, this, true);
 555                         } else {
 556                                 InternalIntersect (interSet, this, other, false);
 557                         }
 558 #endif
 559                         return interSet;
 560                 }
 561
 562                 internal void InternalIntersect (PermissionSet intersect, PermissionSet a, PermissionSet b, bool unrestricted)
 563                 {
 564                         foreach (IPermission p in b.list) {
 565                                 // for every type in both list
 566                                 IPermission i = a.GetPermission (p.GetType ());
 567                                 if (i != null) {
 568                                         // add intersection for this type
 569                                         intersect.AddPermission (p.Intersect (i));
 570                                 }
 571 #if NET_2_0
 572                                 // unrestricted is possible for indentity permissions
 573                                 else if (unrestricted) {
 574 #else
 575                                 else if (unrestricted && (p is IUnrestrictedPermission)) {
 576 #endif
 577                                         intersect.AddPermission (p);
 578                                 }
 579                                 // or reject!
 580                         }
 581                 }
 582
 583 #if NET_2_0
 584                 public bool IsEmpty ()
 585 #else
 586                 public virtual bool IsEmpty ()
 587 #endif
 588                 {
 589                         // note: Unrestricted isn't empty
 590                         if (state == PermissionState.Unrestricted)
 591                                 return false;
 592                         if ((list == null) || (list.Count == 0))
 593                                 return true;
 594                         // the set may include some empty permissions
 595                         foreach (IPermission p in list) {
 596                                 // empty == fully restricted == IsSubsetOf(null) == true
 597                                 if (!p.IsSubsetOf (null))
 598                                         return false;
 599                         }
 600                         return true;
 601                 }
 602
 603 #if NET_2_0
 604                 public bool IsUnrestricted ()
 605 #else
 606                 public virtual bool IsUnrestricted ()
 607 #endif
 608                 {
 609                         return (state == PermissionState.Unrestricted);
 610                 }
 611
 612 #if NET_2_0
 613                 public IPermission RemovePermission (Type permClass)
 614 #else
 615                 public virtual IPermission RemovePermission (Type permClass)
 616 #endif
 617                 {
 618                         if ((permClass == null) || _readOnly)
 619                                 return null;
 620
 621                         foreach (object o in list) {
 622                                 if (o.GetType ().Equals (permClass)) {
 623                                         list.Remove (o);
 624                                         return (IPermission) o;
 625                                 }
 626                         }
 627                         return null;
 628                 }
 629
 630 #if NET_2_0
 631                 public IPermission SetPermission (IPermission perm)
 632 #else
 633                 public virtual IPermission SetPermission (IPermission perm)
 634 #endif
 635                 {
 636                         if ((perm == null) || _readOnly)
 637                                 return perm;
 638 #if NET_2_0
 639                         IUnrestrictedPermission u = (perm as IUnrestrictedPermission);
 640                         if (u == null) {
 641                                 state = PermissionState.None;
 642                         } else {
 643                                 state = u.IsUnrestricted () ? state : PermissionState.None;
 644                         }
 645 #else
 646                         if (perm is IUnrestrictedPermission)
 647                                 state = PermissionState.None;
 648 #endif
 649                         RemovePermission (perm.GetType ());
 650                         list.Add (perm);
 651                         return perm;
 652                 }
 653
 654                 public override string ToString ()
 655                 {
 656                         return ToXml ().ToString ();
 657                 }
 658
 659                 public virtual SecurityElement ToXml ()
 660                 {
 661                         SecurityElement se = new SecurityElement (tagName);
 662                         se.AddAttribute ("class", GetType ().FullName);
 663                         se.AddAttribute ("version", version.ToString ());
 664                         if (state == PermissionState.Unrestricted)
 665                                 se.AddAttribute ("Unrestricted", "true");
 666
 667                         // required for permissions that do not implement IUnrestrictedPermission
 668                         foreach (IPermission p in list) {
 669                                 se.AddChild (p.ToXml ());
 670                         }
 671                         return se;
 672                 }
 673
 674 #if NET_2_0
 675                 public PermissionSet Union (PermissionSet other)
 676 #else
 677                 public virtual PermissionSet Union (PermissionSet other)
 678 #endif
 679                 {
 680                         if (other == null)
 681                                 return this.Copy ();
 682
 683                         PermissionSet copy = null;
 684                         if (this.IsUnrestricted () || other.IsUnrestricted ()) {
 685 #if NET_2_0
 686                                 // there are no child elements in unrestricted permission sets
 687                                 return new PermissionSet (PermissionState.Unrestricted);
 688 #else
 689                                 copy = this.Copy ();
 690                                 // so we keep the "right" type (e.g. NamedPermissionSet)
 691                                 copy.Clear ();
 692                                 copy.state = PermissionState.Unrestricted;
 693                                 // copy all permissions that do not implement IUnrestrictedPermission
 694                                 foreach (IPermission p in this.list) {
 695                                         if (!(p is IUnrestrictedPermission))
 696                                                 copy.AddPermission (p);
 697                                 }
 698                                 foreach (IPermission p in other.list) {
 699                                         if (!(p is IUnrestrictedPermission))
 700                                                 copy.AddPermission (p);
 701                                 }
 702 #endif
 703                         } else {
 704                                 copy = this.Copy ();
 705                                 // PermissionState.None -> copy all permissions
 706                                 foreach (IPermission p in other.list) {
 707                                         copy.AddPermission (p);
 708                                 }
 709                         }
 710                         return copy;
 711                 }
 712
 713                 public virtual int Count {
 714                         get { return list.Count; }
 715                 }
 716
 717                 public virtual bool IsSynchronized {
 718                         get { return list.IsSynchronized; }
 719                 }
 720
 721                 public virtual bool IsReadOnly {
 722                         // always false (as documented) but the PermissionSet can be read-only
 723                         // e.g. in a PolicyStatement
 724                         get { return false; }
 725                 }
 726
 727                 public virtual object SyncRoot {
 728                         get { return this; }
 729                 }
 730
 731                 internal bool DeclarativeSecurity {
 732                         get { return _declsec; }
 733                         set { _declsec = value; }
 734                 }
 735
 736                 [MonoTODO ("may not be required")]
 737                 void IDeserializationCallback.OnDeserialization (object sender)
 738                 {
 739                 }
 740
 741 #if NET_2_0
 742                 [ComVisible (false)]
 743                 public override bool Equals (object obj)
 744                 {
 745                         if (obj == null)
 746                                 return false;
 747                         PermissionSet ps = (obj as PermissionSet);
 748                         if (ps == null)
 749                                 return false;
 750                         if (state != ps.state)
 751                                 return false;
 752                         if (list.Count != ps.Count)
 753                                 return false;
 754
 755                         for (int i=0; i < list.Count; i++) {
 756                                 bool found = false;
 757                                 for (int j=0; i < ps.list.Count; j++) {
 758                                         if (list [i].Equals (ps.list [j])) {
 759                                                 found = true;
 760                                                 break;
 761                                         }
 762                                 }
 763                                 if (!found)
 764                                         return false;
 765                         }
 766                         return true;
 767                 }
 768
 769                 [ComVisible (false)]
 770                 public override int GetHashCode ()
 771                 {
 772                         return (list.Count == 0) ? (int) state : base.GetHashCode ();
 773                 }
 774
 775                 [MonoTODO ("(2.0) what's it doing here? There's probably a reason this was added here.")]
 776                 static public void RevertAssert ()
 777                 {
 778                         CodeAccessPermission.RevertAssert ();
 779                 }
 780 #endif
 781
 782                 // internal
 783
 784                 internal PolicyLevel Resolver {
 785                         get { return _policyLevel; }
 786                         set { _policyLevel = value; }
 787                 }
 788
 789                 internal void SetReadOnly (bool value)
 790                 {
 791                         _readOnly = value;
 792                 }
 793
 794                 private bool AllIgnored ()
 795                 {
 796                         if (_ignored == null)
 797                                 throw new NotSupportedException ("bad bad bad");
 798
 799                         for (int i=0; i < _ignored.Length; i++) {
 800                                 if (!_ignored [i])
 801                                         return false;
 802                         }
 803                         // everything is ignored (i.e. non-CAS permission or asserted permission).
 804                         return true;
 805                 }
 806
 807                 internal bool ProcessFrame (SecurityFrame frame, ref Assembly current, ref AppDomain domain)
 808                 {
 809                         if (IsUnrestricted ()) {
 810                                 // we request unrestricted
 811                                 if (frame.Deny != null) {
 812                                         // but have restrictions (some denied permissions)
 813                                         CodeAccessPermission.ThrowSecurityException (this, "Deny", frame, SecurityAction.Demand, null);
 814                                 } else if ((frame.PermitOnly != null) && !frame.PermitOnly.IsUnrestricted ()) {
 815                                         // but have restrictions (only some permitted permissions)
 816                                         CodeAccessPermission.ThrowSecurityException (this, "PermitOnly", frame, SecurityAction.Demand, null);
 817                                 }
 818                         }
 819
 820                         // skip next steps if no Assert, Deny or PermitOnly are present
 821                         if (frame.HasStackModifiers) {
 822                                 for (int i = 0; i < list.Count; i++) {
 823                                         CodeAccessPermission cap = (CodeAccessPermission) list [i];
 824                                         if (cap.ProcessFrame (frame)) {
 825                                                 _ignored [i] = true; // asserted
 826                                                 if (AllIgnored ())
 827                                                         return true; // no more, abort stack walk!
 828                                         }
 829                                 }
 830                         }
 831
 832                         // however the "final" grant set is resolved by assembly, so
 833                         // there's no need to check it every time (just when we're
 834                         // changing assemblies between frames).
 835                         if (frame.Assembly != current) {
 836                                 CheckAssembly (current, frame);
 837                                 current = frame.Assembly;
 838                         }
 839
 840                         if (frame.Domain != domain) {
 841                                 CheckAppDomain (domain, frame);
 842                                 domain = frame.Domain;
 843                         }
 844
 845                         return false;
 846                 }
 847
 848                 internal void CheckAssembly (Assembly a, SecurityFrame frame)
 849                 {
 850                         IPermission p = SecurityManager.CheckPermissionSet (a, this, false);
 851                         if (p != null) {
 852                                 CodeAccessPermission.ThrowSecurityException (this, "Demand failed assembly permissions checks.",
 853                                         frame, SecurityAction.Demand, p);
 854                         }
 855                 }
 856
 857                 internal void CheckAppDomain (AppDomain domain, SecurityFrame frame)
 858                 {
 859                         IPermission p = SecurityManager.CheckPermissionSet (domain, this);
 860                         if (p != null) {
 861                                 CodeAccessPermission.ThrowSecurityException (this, "Demand failed appdomain permissions checks.",
 862                                         frame, SecurityAction.Demand, p);
 863                         }
 864                 }
 865
 866                 // 2.0 metadata format
 867
 868                 internal static PermissionSet CreateFromBinaryFormat (byte[] data)
 869                 {
 870                         if ((data == null) || (data [0] != 0x2E) || (data.Length < 2)) {
 871                                 string msg = Locale.GetText ("Invalid data in 2.0 metadata format.");
 872                                 throw new SecurityException (msg);
 873                         }
 874
 875                         int pos = 1;
 876                         int numattr = ReadEncodedInt (data, ref pos);
 877                         PermissionSet ps = new PermissionSet (PermissionState.None);
 878                         for (int i = 0; i < numattr; i++) {
 879                                 IPermission p = ProcessAttribute (data, ref pos);
 880                                 if (p == null) {
 881                                         string msg = Locale.GetText ("Unsupported data found in 2.0 metadata format.");
 882                                         throw new SecurityException (msg);
 883                                 }
 884                                 ps.AddPermission (p);
 885                         }
 886                         return ps;
 887                 }
 888
 889                 internal static int ReadEncodedInt (byte[] data, ref int position)
 890                 {
 891                         int len = 0;
 892                         if ((data [position] & 0x80) == 0) {
 893                                 len = data [position];
 894                                 position ++;
 895                         } else if ((data [position] & 0x40) == 0) {
 896                                 len = ((data [position] & 0x3f) << 8 | data [position + 1]);
 897                                 position += 2;
 898                         } else {
 899                                 len = (((data [position] & 0x1f) << 24) | (data [position + 1] << 16) |
 900                                         (data [position + 2] << 8) | (data [position + 3]));
 901                                 position += 4;
 902                         }
 903                         return len;
 904                 }
 905
 906                 static object[] action = new object [1] { (SecurityAction) 0 };
 907
 908                 // TODO: add support for arrays and enums (2.0)
 909                 internal static IPermission ProcessAttribute (byte[] data, ref int position)
 910                 {
 911                         int clen = ReadEncodedInt (data, ref position);
 912                         string cnam = Encoding.UTF8.GetString (data, position, clen);
 913                         position += clen;
 914
 915                         Type secattr = Type.GetType (cnam);
 916                         SecurityAttribute sa = (Activator.CreateInstance (secattr, action) as SecurityAttribute);
 917                         if (sa == null)
 918                                 return null;
 919
 920                         /*int optionalParametersLength =*/ ReadEncodedInt (data, ref position);
 921                         int numberOfParameters = ReadEncodedInt (data, ref position);
 922                         for (int j=0; j < numberOfParameters; j++) {
 923                                 bool property = false;
 924                                 switch (data [position++]) {
 925                                 case 0x53: // field (technically possible and working)
 926                                         property = false;
 927                                         break;
 928                                 case 0x54: // property (common case)
 929                                         property = true;
 930                                         break;
 931                                 default:
 932                                         return null;
 933                                 }
 934
 935                                 bool array = false;
 936                                 byte type = data [position++];
 937                                 if (type == 0x1D) {
 938                                         array = true;
 939                                         type = data [position++];
 940                                 }
 941
 942                                 int plen = ReadEncodedInt (data, ref position);
 943                                 string pnam = Encoding.UTF8.GetString (data, position, plen);
 944                                 position += plen;
 945
 946                                 int arrayLength = 1;
 947                                 if (array) {
 948                                         arrayLength = BitConverter.ToInt32 (data, position);
 949                                         position += 4;
 950                                 }
 951
 952                                 object obj = null;
 953                                 object[] arrayIndex = null;
 954                                 for (int i = 0; i < arrayLength; i++) {
 955                                         if (array) {
 956                                                 // TODO - setup index (2.0)
 957                                         }
 958
 959                                         // sadly type values doesn't match ther TypeCode enum :(
 960                                         switch (type) {
 961                                         case 0x02: // MONO_TYPE_BOOLEAN
 962                                                 obj = (object) Convert.ToBoolean (data [position++]);
 963                                                 break;
 964                                         case 0x03: // MONO_TYPE_CHAR
 965                                                 obj = (object) Convert.ToChar (data [position]);
 966                                                 position += 2;
 967                                                 break;
 968                                         case 0x04: // MONO_TYPE_I1
 969                                                 obj = (object) Convert.ToSByte (data [position++]);
 970                                                 break;
 971                                         case 0x05: // MONO_TYPE_U1
 972                                                 obj = (object) Convert.ToByte (data [position++]);
 973                                                 break;
 974                                         case 0x06: // MONO_TYPE_I2
 975                                                 obj = (object) Convert.ToInt16 (data [position]);
 976                                                 position += 2;
 977                                                 break;
 978                                         case 0x07: // MONO_TYPE_U2
 979                                                 obj = (object) Convert.ToUInt16 (data [position]);
 980                                                 position += 2;
 981                                                 break;
 982                                         case 0x08: // MONO_TYPE_I4
 983                                                 obj = (object) Convert.ToInt32 (data [position]);
 984                                                 position += 4;
 985                                                 break;
 986                                         case 0x09: // MONO_TYPE_U4
 987                                                 obj = (object) Convert.ToUInt32 (data [position]);
 988                                                 position += 4;
 989                                                 break;
 990                                         case 0x0A: // MONO_TYPE_I8
 991                                                 obj = (object) Convert.ToInt64 (data [position]);
 992                                                 position += 8;
 993                                                 break;
 994                                         case 0x0B: // MONO_TYPE_U8
 995                                                 obj = (object) Convert.ToUInt64 (data [position]);
 996                                                 position += 8;
 997                                                 break;
 998                                         case 0x0C: // MONO_TYPE_R4
 999                                                 obj = (object) Convert.ToSingle (data [position]);
1000                                                 position += 4;
1001                                                 break;
1002                                         case 0x0D: // MONO_TYPE_R8
1003                                                 obj = (object) Convert.ToDouble (data [position]);
1004                                                 position += 8;
1005                                                 break;
1006                                         case 0x0E: // MONO_TYPE_STRING
1007                                                 string s = null;
1008                                                 if (data [position] != 0xFF) {
1009                                                         int slen = ReadEncodedInt (data, ref position);
1010                                                         s = Encoding.UTF8.GetString (data, position, slen);
1011                                                         position += slen;
1012                                                 } else {
1013                                                         position++;
1014                                                 }
1015                                                 obj = (object) s;
1016                                                 break;
1017                                         case 0x50: // special for TYPE
1018                                                 int tlen = ReadEncodedInt (data, ref position);
1019                                                 obj = (object) Type.GetType (Encoding.UTF8.GetString (data, position, tlen));
1020                                                 position += tlen;
1021                                                 break;
1022                                         default:
1023                                                 return null; // unsupported
1024                                         }
1025
1026                                         if (property) {
1027                                                 PropertyInfo pi = secattr.GetProperty (pnam);
1028                                                 pi.SetValue (sa, obj, arrayIndex);
1029                                         } else {
1030                                                 FieldInfo fi = secattr.GetField (pnam);
1031                                                 fi.SetValue (sa, obj);
1032                                         }
1033                                 }
1034                         }
1035                         return sa.CreatePermission ();
1036                 }
1037         }
1038 }