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         public abstract class CodeAccessPermission : IPermission, ISecurityEncodable, IStackWalk {
  50
  51
  52                 protected CodeAccessPermission ()
  53                 {
  54                 }
  55
  56                 [MonoTODO ("Imperative mode isn't supported")]
  57                 public void Assert ()
  58                 {
  59                         new PermissionSet (this).Assert ();
  60                 }
  61
  62                 internal bool CheckAssert (CodeAccessPermission asserted)
  63                 {
  64                         if (asserted == null)
  65                                 return false;
  66                         if (asserted.GetType () != this.GetType ())
  67                                 return false;
  68                         return IsSubsetOf (asserted);
  69                 }
  70
  71                 internal bool CheckDemand (CodeAccessPermission target)
  72                 {
  73                         if (target == null)
  74                                 return false;
  75                         if (target.GetType () != this.GetType ())
  76                                 return false;
  77                         return IsSubsetOf (target);
  78                 }
  79
  80                 internal bool CheckDeny (CodeAccessPermission denied)
  81                 {
  82                         if (denied == null)
  83                                 return true;
  84                         Type t = denied.GetType ();
  85                         if (t != this.GetType ())
  86                                 return true;
  87                         IPermission inter = Intersect (denied);
  88                         if (inter == null)
  89                                 return true;
  90                         // sadly that's not enough :( at this stage we must also check
  91                         // if an empty (PermissionState.None) is a subset of the denied
  92                         // (which is like a empty intersection looks like for flag based
  93                         // permissions, e.g. AspNetHostingPermission).
  94                         return denied.IsSubsetOf (PermissionBuilder.Create (t));
  95                 }
  96
  97                 internal bool CheckPermitOnly (CodeAccessPermission target)
  98                 {
  99                         if (target == null)
 100                                 return false;
 101                         if (target.GetType () != this.GetType ())
 102                                 return false;
 103                         return IsSubsetOf (target);
 104                 }
 105
 106                 public abstract IPermission Copy ();
 107
 108                 public void Demand ()
 109                 {
 110                         // note: here we're sure it's a CAS demand
 111                         if (!SecurityManager.SecurityEnabled)
 112                                 return;
 113
 114                         // skip frames until we get the caller (of our caller)
 115                         new PermissionSet (this).CasOnlyDemand (3);
 116                 }
 117
 118                 [MonoTODO ("Imperative mode isn't supported")]
 119                 public void Deny ()
 120                 {
 121                         new PermissionSet (this).Deny ();
 122                 }
 123
 124 #if NET_2_0
 125                 [ComVisible (false)]
 126                 public override bool Equals (object obj)
 127                 {
 128                         if (obj == null)
 129                                 return false;
 130                         if (obj.GetType () != this.GetType ())
 131                                 return false;
 132                         CodeAccessPermission cap = (obj as CodeAccessPermission);
 133                         return (IsSubsetOf (cap) && cap.IsSubsetOf (this));
 134                 }
 135 #endif
 136
 137                 public abstract void FromXml (SecurityElement elem);
 138
 139 #if NET_2_0
 140                 [ComVisible (false)]
 141                 public override int GetHashCode ()
 142                 {
 143                         return base.GetHashCode ();
 144                 }
 145 #endif
 146
 147                 public abstract IPermission Intersect (IPermission target);
 148
 149                 public abstract bool IsSubsetOf (IPermission target);
 150
 151                 public override string ToString ()
 152                 {
 153                         SecurityElement elem = ToXml ();
 154                         return elem.ToString ();
 155                 }
 156
 157                 public abstract SecurityElement ToXml ();
 158
 159                 public virtual IPermission Union (IPermission other)
 160                 {
 161                         if (null != other)
 162                                 throw new System.NotSupportedException (); // other is not null.
 163                         return null;
 164                 }
 165
 166                 [MonoTODO ("Imperative mode isn't supported")]
 167                 public void PermitOnly ()
 168                 {
 169                         new PermissionSet (this).PermitOnly ();
 170                 }
 171
 172                 [MonoTODO ("Imperative mode isn't supported")]
 173                 public static void RevertAll ()
 174                 {
 175                         if (!SecurityManager.SecurityEnabled)
 176                                 return;
 177
 178                         SecurityFrame sf = new SecurityFrame (1);
 179                         bool revert = false;
 180                         if ((sf.Assert != null) && !sf.Assert.DeclarativeSecurity) {
 181                                 revert = true;
 182                                 throw new NotSupportedException ("Currently only declarative Assert are supported.");
 183                         }
 184                         if ((sf.Deny != null) && !sf.Deny.DeclarativeSecurity) {
 185                                 revert = true;
 186                                 throw new NotSupportedException ("Currently only declarative Deny are supported.");
 187                         }
 188                         if ((sf.PermitOnly != null) && !sf.PermitOnly.DeclarativeSecurity) {
 189                                 revert = true;
 190                                 throw new NotSupportedException ("Currently only declarative PermitOnly are supported.");
 191                         }
 192
 193                         if (!revert) {
 194                                 string msg = Locale.GetText ("No stack modifiers are present on the current stack frame.");
 195                                 // FIXME: we don't (yet) support imperative stack modifiers
 196                                 msg += Environment.NewLine + "Currently only declarative stack modifiers are supported.";
 197                                 throw new ExecutionEngineException (msg);
 198                         }
 199                 }
 200
 201                 [MonoTODO ("Imperative mode isn't supported")]
 202                 public static void RevertAssert ()
 203                 {
 204                         if (!SecurityManager.SecurityEnabled)
 205                                 return;
 206
 207                         SecurityFrame sf = new SecurityFrame (1);
 208                         if ((sf.Assert != null) && !sf.Assert.DeclarativeSecurity) {
 209                                 throw new NotSupportedException ("Currently only declarative Assert are supported.");
 210                         } else {
 211                                 // we can't revert declarative security (or an empty frame) imperatively
 212                                 ThrowExecutionEngineException (SecurityAction.Assert);
 213                         }
 214                 }
 215
 216                 [MonoTODO ("Imperative mode isn't supported")]
 217                 public static void RevertDeny ()
 218                 {
 219                         if (!SecurityManager.SecurityEnabled)
 220                                 return;
 221
 222                         SecurityFrame sf = new SecurityFrame (1);
 223                         if ((sf.Deny != null) && !sf.Deny.DeclarativeSecurity) {
 224                                 throw new NotSupportedException ("Currently only declarative Deny are supported.");
 225                         } else {
 226                                 // we can't revert declarative security (or an empty frame) imperatively
 227                                 ThrowExecutionEngineException (SecurityAction.Deny);
 228                         }
 229                 }
 230
 231                 [MonoTODO ("Imperative mode isn't supported")]
 232                 public static void RevertPermitOnly ()
 233                 {
 234                         if (!SecurityManager.SecurityEnabled)
 235                                 return;
 236
 237                         SecurityFrame sf = new SecurityFrame (1);
 238                         if ((sf.PermitOnly != null) && sf.PermitOnly.DeclarativeSecurity) {
 239                                 throw new NotSupportedException ("Currently only declarative PermitOnly are supported.");
 240                         } else {
 241                                 // we can't revert declarative security (or an empty frame) imperatively
 242                                 ThrowExecutionEngineException (SecurityAction.PermitOnly);
 243                         }
 244                 }
 245
 246                 // Internal helpers methods
 247
 248                 // snippet moved from FileIOPermission (nickd) to be reused in all derived classes
 249                 internal SecurityElement Element (int version)
 250                 {
 251                         SecurityElement se = new SecurityElement ("IPermission");
 252                         Type type = this.GetType ();
 253                         se.AddAttribute ("class", type.FullName + ", " + type.Assembly.ToString ().Replace ('\"', '\''));
 254                         se.AddAttribute ("version", version.ToString ());
 255                         return se;
 256                 }
 257
 258                 internal static PermissionState CheckPermissionState (PermissionState state, bool allowUnrestricted)
 259                 {
 260                         string msg;
 261                         switch (state) {
 262                         case PermissionState.None:
 263                                 break;
 264                         case PermissionState.Unrestricted:
 265 #if NET_2_0
 266                                 // unrestricted permissions are possible for identiy permissions
 267 #else
 268                                 if (!allowUnrestricted) {
 269                                         msg = Locale.GetText ("Unrestricted isn't not allowed for identity permissions.");
 270                                         throw new ArgumentException (msg, "state");
 271                                 }
 272 #endif
 273                                 break;
 274                         default:
 275                                 msg = String.Format (Locale.GetText ("Invalid enum {0}"), state);
 276                                 throw new ArgumentException (msg, "state");
 277                         }
 278                         return state;
 279                 }
 280
 281                 internal static int CheckSecurityElement (SecurityElement se, string parameterName, int minimumVersion, int maximumVersion)
 282                 {
 283                         if (se == null)
 284                                 throw new ArgumentNullException (parameterName);
 285
 286                         // Tag is case-sensitive
 287                         if (se.Tag != "IPermission") {
 288                                 string msg = String.Format (Locale.GetText ("Invalid tag {0}"), se.Tag);
 289                                 throw new ArgumentException (msg, parameterName);
 290                         }
 291
 292                         // Note: we do not care about the class attribute at
 293                         // this stage (in fact we don't even if the class
 294                         // attribute is present or not). Anyway the object has
 295                         // already be created, with success, if we're loading it
 296
 297                         // we assume minimum version if no version number is supplied
 298                         int version = minimumVersion;
 299                         string v = se.Attribute ("version");
 300                         if (v != null) {
 301                                 try {
 302                                         version = Int32.Parse (v);
 303                                 }
 304                                 catch (Exception e) {
 305                                         string msg = Locale.GetText ("Couldn't parse version from '{0}'.");
 306                                         msg = String.Format (msg, v);
 307                                         throw new ArgumentException (msg, parameterName, e);
 308                                 }
 309                         }
 310
 311                         if ((version < minimumVersion) || (version > maximumVersion)) {
 312                                 string msg = Locale.GetText ("Unknown version '{0}', expected versions between ['{1}','{2}'].");
 313                                 msg = String.Format (msg, version, minimumVersion, maximumVersion);
 314                                 throw new ArgumentException (msg, parameterName);
 315                         }
 316                         return version;
 317                 }
 318
 319                 // must be called after CheckSecurityElement (i.e. se != null)
 320                 internal static bool IsUnrestricted (SecurityElement se)
 321                 {
 322                         string value = se.Attribute ("Unrestricted");
 323                         if (value == null)
 324                                 return false;
 325                         return (String.Compare (value, Boolean.TrueString, true, CultureInfo.InvariantCulture) == 0);
 326                 }
 327
 328                 internal bool ProcessFrame (SecurityFrame frame)
 329                 {
 330                         // 1. CheckPermitOnly
 331                         if (frame.PermitOnly != null) {
 332                                 // the demanded permission must be in one of the permitted...
 333                                 bool permit = frame.PermitOnly.IsUnrestricted ();
 334                                 if (!permit) {
 335                                         // check individual permissions
 336                                         foreach (IPermission p in frame.PermitOnly) {
 337                                                 if (CheckPermitOnly (p as CodeAccessPermission)) {
 338                                                         permit = true;
 339                                                         break;
 340                                                 }
 341                                         }
 342                                 }
 343                                 if (!permit) {
 344                                         // ...or else we throw
 345                                         ThrowSecurityException (this, "PermitOnly", frame, SecurityAction.Demand, null);
 346                                 }
 347                         }
 348
 349                         // 2. CheckDeny
 350                         if (frame.Deny != null) {
 351                                 // special case where everything is denied (i.e. no child to be processed)
 352                                 if (frame.Deny.IsUnrestricted ())
 353                                         ThrowSecurityException (this, "Deny", frame, SecurityAction.Demand, null);
 354                                 foreach (IPermission p in frame.Deny) {
 355                                         if (!CheckDeny (p as CodeAccessPermission))
 356                                                 ThrowSecurityException (this, "Deny", frame, SecurityAction.Demand, p);
 357                                 }
 358                         }
 359
 360                         // 3. CheckAssert
 361                         if (frame.Assert != null) {
 362                                 if (frame.Assert.IsUnrestricted ())
 363                                         return true; // remove permission and continue stack walk
 364                                 foreach (IPermission p in frame.Assert) {
 365                                         if (CheckAssert (p as CodeAccessPermission)) {
 366                                                 return true; // remove permission and continue stack walk
 367                                         }
 368                                 }
 369                         }
 370
 371                         // continue the stack walk
 372                         return false;
 373                 }
 374
 375                 internal static void ThrowInvalidPermission (IPermission target, Type expected)
 376                 {
 377                         string msg = Locale.GetText ("Invalid permission type '{0}', expected type '{1}'.");
 378                         msg = String.Format (msg, target.GetType (), expected);
 379                         throw new ArgumentException (msg, "target");
 380                 }
 381
 382                 internal static void ThrowExecutionEngineException (SecurityAction stackmod)
 383                 {
 384                         string msg = Locale.GetText ("No {0} modifier is present on the current stack frame.");
 385                         // FIXME: we don't (yet) support imperative stack modifiers
 386                         msg += Environment.NewLine + "Currently only declarative stack modifiers are supported.";
 387                         throw new ExecutionEngineException (String.Format (msg, stackmod));
 388                 }
 389
 390                 internal static void ThrowSecurityException (object demanded, string message, SecurityFrame frame,
 391                         SecurityAction action, IPermission failed)
 392                 {
 393                         Assembly a = frame.Assembly;
 394                         throw new SecurityException (Locale.GetText (message),
 395                                 a.UnprotectedGetName (), a.GrantedPermissionSet,
 396                                 a.DeniedPermissionSet, frame.Method, action, demanded,
 397                                 failed, a.UnprotectedGetEvidence ());
 398                 }
 399         }
 400 }