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

   1 //
   2 // System.Security.CodeAccessPermission.cs
   3 //
   4 // Authors:
   5 //      Miguel de Icaza (miguel@ximian.com)
   6 //      Nick Drochak, ndrochak@gol.com
   7 //      Sebastien Pouliot  <sebastien@ximian.com>
   8 //
   9 // (C) Ximian, Inc. http://www.ximian.com
  10 // Copyright (C) 2001 Nick Drochak, All Rights Reserved
  11 // Portions (C) 2004 Motus Technologies Inc. (http://www.motus.com)
  12 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Diagnostics;
  35 using System.Globalization;
  36 using System.Reflection;
  37 using System.Runtime.CompilerServices;
  38 using System.Runtime.InteropServices;
  39 using System.Security.Permissions;
  40 using System.Threading;
  41
  42 namespace System.Security {
  43
  44         [Serializable]
  45         [SecurityPermission (SecurityAction.InheritanceDemand, ControlEvidence = true, ControlPolicy = true)]
  46 #if NET_2_0
  47         [ComVisible (true)]
  48 #endif
  49         [MonoTODO ("CAS support is experimental (and unsupported).")]
  50         public abstract class CodeAccessPermission : IPermission, ISecurityEncodable, IStackWalk {
  51
  52
  53                 protected CodeAccessPermission ()
  54                 {
  55                 }
  56
  57                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
  58                 public void Assert ()
  59                 {
  60                         new PermissionSet (this).Assert ();
  61                 }
  62
  63                 internal bool CheckAssert (CodeAccessPermission asserted)
  64                 {
  65                         if (asserted == null)
  66                                 return false;
  67                         if (asserted.GetType () != this.GetType ())
  68                                 return false;
  69                         return IsSubsetOf (asserted);
  70                 }
  71
  72                 internal bool CheckDemand (CodeAccessPermission target)
  73                 {
  74                         if (target == null)
  75                                 return false;
  76                         if (target.GetType () != this.GetType ())
  77                                 return false;
  78                         return IsSubsetOf (target);
  79                 }
  80
  81                 internal bool CheckDeny (CodeAccessPermission denied)
  82                 {
  83                         if (denied == null)
  84                                 return true;
  85                         Type t = denied.GetType ();
  86                         if (t != this.GetType ())
  87                                 return true;
  88                         IPermission inter = Intersect (denied);
  89                         if (inter == null)
  90                                 return true;
  91                         // sadly that's not enough :( at this stage we must also check
  92                         // if an empty (PermissionState.None) is a subset of the denied
  93                         // (which is like a empty intersection looks like for flag based
  94                         // permissions, e.g. AspNetHostingPermission).
  95                         return denied.IsSubsetOf (PermissionBuilder.Create (t));
  96                 }
  97
  98                 internal bool CheckPermitOnly (CodeAccessPermission target)
  99                 {
 100                         if (target == null)
 101                                 return false;
 102                         if (target.GetType () != this.GetType ())
 103                                 return false;
 104                         return IsSubsetOf (target);
 105                 }
 106
 107                 public abstract IPermission Copy ();
 108
 109                 public void Demand ()
 110                 {
 111                         // note: here we're sure it's a CAS demand
 112                         if (!SecurityManager.SecurityEnabled)
 113                                 return;
 114
 115                         // skip frames until we get the caller (of our caller)
 116                         new PermissionSet (this).CasOnlyDemand (3);
 117                 }
 118
 119                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
 120                 public void Deny ()
 121                 {
 122                         new PermissionSet (this).Deny ();
 123                 }
 124
 125 #if NET_2_0
 126                 [ComVisible (false)]
 127                 public override bool Equals (object obj)
 128                 {
 129                         if (obj == null)
 130                                 return false;
 131                         if (obj.GetType () != this.GetType ())
 132                                 return false;
 133                         CodeAccessPermission cap = (obj as CodeAccessPermission);
 134                         return (IsSubsetOf (cap) && cap.IsSubsetOf (this));
 135                 }
 136 #endif
 137
 138                 public abstract void FromXml (SecurityElement elem);
 139
 140 #if NET_2_0
 141                 [ComVisible (false)]
 142                 public override int GetHashCode ()
 143                 {
 144                         return base.GetHashCode ();
 145                 }
 146 #endif
 147
 148                 public abstract IPermission Intersect (IPermission target);
 149
 150                 public abstract bool IsSubsetOf (IPermission target);
 151
 152                 public override string ToString ()
 153                 {
 154                         SecurityElement elem = ToXml ();
 155                         return elem.ToString ();
 156                 }
 157
 158                 public abstract SecurityElement ToXml ();
 159
 160                 public virtual IPermission Union (IPermission other)
 161                 {
 162                         if (null != other)
 163                                 throw new System.NotSupportedException (); // other is not null.
 164                         return null;
 165                 }
 166
 167                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
 168                 public void PermitOnly ()
 169                 {
 170                         new PermissionSet (this).PermitOnly ();
 171                 }
 172
 173                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
 174                 public static void RevertAll ()
 175                 {
 176                         if (!SecurityManager.SecurityEnabled)
 177                                 return;
 178
 179                         SecurityFrame sf = new SecurityFrame (1);
 180                         bool revert = false;
 181                         if ((sf.Assert != null) && !sf.Assert.DeclarativeSecurity) {
 182                                 revert = true;
 183                                 throw new NotSupportedException ("Currently only declarative Assert are supported.");
 184                         }
 185                         if ((sf.Deny != null) && !sf.Deny.DeclarativeSecurity) {
 186                                 revert = true;
 187                                 throw new NotSupportedException ("Currently only declarative Deny are supported.");
 188                         }
 189                         if ((sf.PermitOnly != null) && !sf.PermitOnly.DeclarativeSecurity) {
 190                                 revert = true;
 191                                 throw new NotSupportedException ("Currently only declarative PermitOnly are supported.");
 192                         }
 193
 194                         if (!revert) {
 195                                 string msg = Locale.GetText ("No stack modifiers are present on the current stack frame.");
 196                                 // FIXME: we don't (yet) support imperative stack modifiers
 197                                 msg += Environment.NewLine + "Currently only declarative stack modifiers are supported.";
 198                                 throw new ExecutionEngineException (msg);
 199                         }
 200                 }
 201
 202                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
 203                 public static void RevertAssert ()
 204                 {
 205                         if (!SecurityManager.SecurityEnabled)
 206                                 return;
 207
 208                         SecurityFrame sf = new SecurityFrame (1);
 209                         if ((sf.Assert != null) && !sf.Assert.DeclarativeSecurity) {
 210                                 throw new NotSupportedException ("Currently only declarative Assert are supported.");
 211                         } else {
 212                                 // we can't revert declarative security (or an empty frame) imperatively
 213                                 ThrowExecutionEngineException (SecurityAction.Assert);
 214                         }
 215                 }
 216
 217                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
 218                 public static void RevertDeny ()
 219                 {
 220                         if (!SecurityManager.SecurityEnabled)
 221                                 return;
 222
 223                         SecurityFrame sf = new SecurityFrame (1);
 224                         if ((sf.Deny != null) && !sf.Deny.DeclarativeSecurity) {
 225                                 throw new NotSupportedException ("Currently only declarative Deny are supported.");
 226                         } else {
 227                                 // we can't revert declarative security (or an empty frame) imperatively
 228                                 ThrowExecutionEngineException (SecurityAction.Deny);
 229                         }
 230                 }
 231
 232                 [MonoTODO ("CAS support is experimental (and unsupported). Imperative mode is not implemented.")]
 233                 public static void RevertPermitOnly ()
 234                 {
 235                         if (!SecurityManager.SecurityEnabled)
 236                                 return;
 237
 238                         SecurityFrame sf = new SecurityFrame (1);
 239                         if ((sf.PermitOnly != null) && sf.PermitOnly.DeclarativeSecurity) {
 240                                 throw new NotSupportedException ("Currently only declarative PermitOnly are supported.");
 241                         } else {
 242                                 // we can't revert declarative security (or an empty frame) imperatively
 243                                 ThrowExecutionEngineException (SecurityAction.PermitOnly);
 244                         }
 245                 }
 246
 247                 // Internal helpers methods
 248
 249                 // snippet moved from FileIOPermission (nickd) to be reused in all derived classes
 250                 internal SecurityElement Element (int version)
 251                 {
 252                         SecurityElement se = new SecurityElement ("IPermission");
 253                         Type type = this.GetType ();
 254                         se.AddAttribute ("class", type.FullName + ", " + type.Assembly.ToString ().Replace ('\"', '\''));
 255                         se.AddAttribute ("version", version.ToString ());
 256                         return se;
 257                 }
 258
 259                 internal static PermissionState CheckPermissionState (PermissionState state, bool allowUnrestricted)
 260                 {
 261                         string msg;
 262                         switch (state) {
 263                         case PermissionState.None:
 264                                 break;
 265                         case PermissionState.Unrestricted:
 266 #if NET_2_0
 267                                 // unrestricted permissions are possible for identiy permissions
 268 #else
 269                                 if (!allowUnrestricted) {
 270                                         msg = Locale.GetText ("Unrestricted isn't not allowed for identity permissions.");
 271                                         throw new ArgumentException (msg, "state");
 272                                 }
 273 #endif
 274                                 break;
 275                         default:
 276                                 msg = String.Format (Locale.GetText ("Invalid enum {0}"), state);
 277                                 throw new ArgumentException (msg, "state");
 278                         }
 279                         return state;
 280                 }
 281
 282                 internal static int CheckSecurityElement (SecurityElement se, string parameterName, int minimumVersion, int maximumVersion)
 283                 {
 284                         if (se == null)
 285                                 throw new ArgumentNullException (parameterName);
 286
 287                         // Tag is case-sensitive
 288                         if (se.Tag != "IPermission") {
 289                                 string msg = String.Format (Locale.GetText ("Invalid tag {0}"), se.Tag);
 290                                 throw new ArgumentException (msg, parameterName);
 291                         }
 292
 293                         // Note: we do not care about the class attribute at
 294                         // this stage (in fact we don't even if the class
 295                         // attribute is present or not). Anyway the object has
 296                         // already be created, with success, if we're loading it
 297
 298                         // we assume minimum version if no version number is supplied
 299                         int version = minimumVersion;
 300                         string v = se.Attribute ("version");
 301                         if (v != null) {
 302                                 try {
 303                                         version = Int32.Parse (v);
 304                                 }
 305                                 catch (Exception e) {
 306                                         string msg = Locale.GetText ("Couldn't parse version from '{0}'.");
 307                                         msg = String.Format (msg, v);
 308                                         throw new ArgumentException (msg, parameterName, e);
 309                                 }
 310                         }
 311
 312                         if ((version < minimumVersion) || (version > maximumVersion)) {
 313                                 string msg = Locale.GetText ("Unknown version '{0}', expected versions between ['{1}','{2}'].");
 314                                 msg = String.Format (msg, version, minimumVersion, maximumVersion);
 315                                 throw new ArgumentException (msg, parameterName);
 316                         }
 317                         return version;
 318                 }
 319
 320                 // must be called after CheckSecurityElement (i.e. se != null)
 321                 internal static bool IsUnrestricted (SecurityElement se)
 322                 {
 323                         string value = se.Attribute ("Unrestricted");
 324                         if (value == null)
 325                                 return false;
 326                         return (String.Compare (value, Boolean.TrueString, true, CultureInfo.InvariantCulture) == 0);
 327                 }
 328
 329                 internal bool ProcessFrame (SecurityFrame frame)
 330                 {
 331                         // 1. CheckPermitOnly
 332                         if (frame.PermitOnly != null) {
 333                                 // the demanded permission must be in one of the permitted...
 334                                 bool permit = frame.PermitOnly.IsUnrestricted ();
 335                                 if (!permit) {
 336                                         // check individual permissions
 337                                         foreach (IPermission p in frame.PermitOnly) {
 338                                                 if (CheckPermitOnly (p as CodeAccessPermission)) {
 339                                                         permit = true;
 340                                                         break;
 341                                                 }
 342                                         }
 343                                 }
 344                                 if (!permit) {
 345                                         // ...or else we throw
 346                                         ThrowSecurityException (this, "PermitOnly", frame, SecurityAction.Demand, null);
 347                                 }
 348                         }
 349
 350                         // 2. CheckDeny
 351                         if (frame.Deny != null) {
 352                                 // special case where everything is denied (i.e. no child to be processed)
 353                                 if (frame.Deny.IsUnrestricted ())
 354                                         ThrowSecurityException (this, "Deny", frame, SecurityAction.Demand, null);
 355                                 foreach (IPermission p in frame.Deny) {
 356                                         if (!CheckDeny (p as CodeAccessPermission))
 357                                                 ThrowSecurityException (this, "Deny", frame, SecurityAction.Demand, p);
 358                                 }
 359                         }
 360
 361                         // 3. CheckAssert
 362                         if (frame.Assert != null) {
 363                                 if (frame.Assert.IsUnrestricted ())
 364                                         return true; // remove permission and continue stack walk
 365                                 foreach (IPermission p in frame.Assert) {
 366                                         if (CheckAssert (p as CodeAccessPermission)) {
 367                                                 return true; // remove permission and continue stack walk
 368                                         }
 369                                 }
 370                         }
 371
 372                         // continue the stack walk
 373                         return false;
 374                 }
 375
 376                 internal static void ThrowInvalidPermission (IPermission target, Type expected)
 377                 {
 378                         string msg = Locale.GetText ("Invalid permission type '{0}', expected type '{1}'.");
 379                         msg = String.Format (msg, target.GetType (), expected);
 380                         throw new ArgumentException (msg, "target");
 381                 }
 382
 383                 internal static void ThrowExecutionEngineException (SecurityAction stackmod)
 384                 {
 385                         string msg = Locale.GetText ("No {0} modifier is present on the current stack frame.");
 386                         // FIXME: we don't (yet) support imperative stack modifiers
 387                         msg += Environment.NewLine + "Currently only declarative stack modifiers are supported.";
 388                         throw new ExecutionEngineException (String.Format (msg, stackmod));
 389                 }
 390
 391                 internal static void ThrowSecurityException (object demanded, string message, SecurityFrame frame,
 392                         SecurityAction action, IPermission failed)
 393                 {
 394 #if NET_2_1
 395                         throw new SecurityException (message);
 396 #else
 397                         Assembly a = frame.Assembly;
 398                         throw new SecurityException (Locale.GetText (message),
 399                                 a.UnprotectedGetName (), a.GrantedPermissionSet,
 400                                 a.DeniedPermissionSet, frame.Method, action, demanded,
 401                                 failed, a.UnprotectedGetEvidence ());
 402 #endif
 403                 }
 404         }
 405 }