mcs/tools/tuner/Mono.Tuner/InjectSecurityAttributes.cs

   1 //
   2 // InjectSecurityAttributes.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@novell.com)
   6 //
   7 // (C) 2009 Novell, Inc.
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Collections;
  31 using System.IO;
  32 using System.Linq;
  33 using System.Text;
  34
  35 using Mono.Linker;
  36 using Mono.Linker.Steps;
  37
  38 using Mono.Cecil;
  39 using Mono.Cecil.Cil;
  40
  41 namespace Mono.Tuner {
  42
  43         public class InjectSecurityAttributes : BaseStep {
  44
  45                 enum TargetKind {
  46                         Type,
  47                         Method,
  48                 }
  49
  50                 protected enum AttributeType {
  51                         Critical,
  52                         SafeCritical,
  53                 }
  54
  55                 const string _safe_critical = "System.Security.SecuritySafeCriticalAttribute";
  56                 const string _critical = "System.Security.SecurityCriticalAttribute";
  57                 const string _system_void = "System.Void";
  58
  59                 const string sec_attr_folder = "secattrs";
  60
  61                 protected AssemblyDefinition _assembly;
  62
  63                 MethodDefinition _safe_critical_ctor;
  64                 MethodDefinition _critical_ctor;
  65                 TypeDefinition _void_type;
  66
  67                 string data_folder;
  68
  69                 protected override bool ConditionToProcess ()
  70                 {
  71                         if (!Context.HasParameter (sec_attr_folder)) {
  72                                 Console.Error.WriteLine ("Warning: no secattrs folder specified.");
  73                                 return false;
  74                         }
  75
  76                         data_folder = Context.GetParameter (sec_attr_folder);
  77                         return true;
  78                 }
  79
  80                 protected override void ProcessAssembly (AssemblyDefinition assembly)
  81                 {
  82                         if (Annotations.GetAction (assembly) != AssemblyAction.Link)
  83                                 return;
  84
  85                         string secattr_file = Path.Combine (
  86                                 data_folder,
  87                                 assembly.Name.Name + ".secattr");
  88
  89                         if (!File.Exists (secattr_file)) {
  90                                 Console.Error.WriteLine ("Warning: file '{0}' not found, skipping.", secattr_file);
  91                                 return;
  92                         }
  93
  94                         _assembly = assembly;
  95
  96                         // remove existing [SecurityCritical] and [SecuritySafeCritical]
  97                         RemoveSecurityAttributes ();
  98
  99                         // add [SecurityCritical] and [SecuritySafeCritical] from the data file
 100                         ProcessSecurityAttributeFile (secattr_file);
 101                 }
 102
 103                 protected void RemoveSecurityAttributes ()
 104                 {
 105                         foreach (TypeDefinition type in _assembly.MainModule.Types) {
 106                                 if (RemoveSecurityAttributes (type))
 107                                         type.HasSecurity = false;
 108
 109                                 if (type.HasMethods) {
 110                                         foreach (MethodDefinition method in type.Methods) {
 111                                                 if (RemoveSecurityAttributes (method))
 112                                                         method.HasSecurity = false;
 113                                         }
 114                                 }
 115                         }
 116                 }
 117
 118                 static bool RemoveSecurityDeclarations (ISecurityDeclarationProvider provider)
 119                 {
 120                         // also remove already existing CAS security declarations
 121
 122                         if (provider == null)
 123                                 return false;
 124
 125                         if (!provider.HasSecurityDeclarations)
 126                                 return false;
 127
 128                         provider.SecurityDeclarations.Clear ();
 129                         return true;
 130                 }
 131
 132                 static bool RemoveSecurityAttributes (ICustomAttributeProvider provider)
 133                 {
 134                         bool result = RemoveSecurityDeclarations (provider as ISecurityDeclarationProvider);
 135
 136                         if (!provider.HasCustomAttributes)
 137                                 return result;
 138
 139                         var attributes = provider.CustomAttributes;
 140                         for (int i = 0; i < attributes.Count; i++) {
 141                                 CustomAttribute attribute = attributes [i];
 142                                 switch (attribute.Constructor.DeclaringType.FullName) {
 143                                 case _safe_critical:
 144                                 case _critical:
 145                                         attributes.RemoveAt (i--);
 146                                         break;
 147                                 }
 148                         }
 149                         return result;
 150                 }
 151
 152                 void ProcessSecurityAttributeFile (string file)
 153                 {
 154                         using (StreamReader reader = File.OpenText (file)) {
 155                                 string line;
 156                                 while ((line = reader.ReadLine ()) != null)
 157                                         ProcessLine (line);
 158                         }
 159                 }
 160
 161                 void ProcessLine (string line)
 162                 {
 163                         if (line == null || line.Length < 6 || line [0] == '#')
 164                                 return;
 165
 166                         int sep = line.IndexOf (": ");
 167                         if (sep == -1)
 168                                 return;
 169
 170                         string marker = line.Substring (0, sep);
 171                         string target = line.Substring (sep + 2);
 172
 173                         ProcessSecurityAttributeEntry (
 174                                 DecomposeAttributeType (marker),
 175                                 DecomposeTargetKind (marker),
 176                                 target);
 177                 }
 178
 179                 static AttributeType DecomposeAttributeType (string marker)
 180                 {
 181                         if (marker.StartsWith ("SC"))
 182                                 return AttributeType.Critical;
 183                         else if (marker.StartsWith ("SSC"))
 184                                 return AttributeType.SafeCritical;
 185                         else
 186                                 throw new ArgumentException ();
 187                 }
 188
 189                 static TargetKind DecomposeTargetKind (string marker)
 190                 {
 191                         switch (marker [marker.Length - 1]) {
 192                         case 'T':
 193                                 return TargetKind.Type;
 194                         case 'M':
 195                                 return TargetKind.Method;
 196                         default:
 197                                 throw new ArgumentException ();
 198                         }
 199                 }
 200
 201                 public static bool NeedsDefaultConstructor (TypeDefinition type)
 202                 {
 203                         if (type.IsInterface)
 204                                 return false;
 205
 206                         TypeReference base_type = type.BaseType;
 207                         if ((base_type == null) || (base_type.Namespace != "System"))
 208                                 return true;
 209
 210                         return ((base_type.Name != "Delegate") && (base_type.Name != "MulticastDelegate"));
 211                 }
 212
 213                 void ProcessSecurityAttributeEntry (AttributeType type, TargetKind kind, string target)
 214                 {
 215                         ICustomAttributeProvider provider = GetTarget (kind, target);
 216                         if (provider == null) {
 217                                 Console.Error.WriteLine ("Warning: entry '{0}' could not be found", target);
 218                                 return;
 219                         }
 220
 221                         // we need to be smarter when applying the attributes (mostly SC) to types
 222                         if (kind == TargetKind.Type) {
 223                                 TypeDefinition td = (provider as TypeDefinition);
 224                                 // ensure [SecurityCritical] types (well most) have a default constructor
 225                                 if ((type == AttributeType.Critical) && NeedsDefaultConstructor (td)) {
 226                                         if (GetDefaultConstructor (td) == null) {
 227                                                 // Console.Error.WriteLine ("Info: adding default ctor for '{0}'", td);
 228                                                 td.Methods.Add (CreateDefaultConstructor ());
 229                                         }
 230                                 }
 231
 232                                 // it's easier for some tools (e.g. less false positives in fxcop)
 233                                 // and also quicker for the runtime (one less lookup) if all methods gets decorated
 234                                 foreach (MethodDefinition method in td.Methods) {
 235                                         bool skip = false;
 236
 237                                         AttributeType mtype = type;
 238                                         // there are cases where an SC cannot be applied to some methods
 239                                         switch (method.Name) {
 240                                         // e.g. everything we override from System.Object (which is transparent)
 241                                         case "Equals":
 242                                                 skip = method.Parameters.Count == 1 && method.Parameters [0].ParameterType.FullName == "System.Object";
 243                                                 break;
 244                                         case "Finalize":
 245                                         case "GetHashCode":
 246                                         case "ToString":
 247                                                 skip = !method.HasParameters;
 248                                                 break;
 249                                         // e.g. some transparent interfaces, like IDisposable (implicit or explicit)
 250                                         // downgrade some SC into SSC to respect the override/inheritance rules
 251                                         case "System.IDisposable.Dispose":
 252                                         case "Dispose":
 253                                                 skip = !method.HasParameters;
 254                                                 break;
 255                                         }
 256
 257                                         if (skip)
 258                                                 continue;
 259
 260                                         switch (mtype) {
 261                                         case AttributeType.Critical:
 262                                                 AddCriticalAttribute (method);
 263                                                 break;
 264                                         case AttributeType.SafeCritical:
 265                                                 AddSafeCriticalAttribute (method);
 266                                                 break;
 267                                         }
 268                                 }
 269                         }
 270
 271                         switch (type) {
 272                         case AttributeType.Critical:
 273                                 AddCriticalAttribute (provider);
 274                                 break;
 275                         case AttributeType.SafeCritical:
 276                                 AddSafeCriticalAttribute (provider);
 277                                 break;
 278                         }
 279                 }
 280
 281                 protected void AddCriticalAttribute (ICustomAttributeProvider provider)
 282                 {
 283                         // a [SecurityCritical] replaces a [SecuritySafeCritical]
 284                         if (HasSecurityAttribute (provider, AttributeType.SafeCritical))
 285                                 RemoveSecurityAttributes (provider);
 286
 287                         AddSecurityAttribute (provider, AttributeType.Critical);
 288                 }
 289
 290                 void AddSafeCriticalAttribute (ICustomAttributeProvider provider)
 291                 {
 292                         // a [SecuritySafeCritical] is ignored if a [SecurityCritical] is present
 293                         if (HasSecurityAttribute (provider, AttributeType.Critical))
 294                                 return;
 295
 296                         AddSecurityAttribute (provider, AttributeType.SafeCritical);
 297                 }
 298
 299                 void AddSecurityAttribute (ICustomAttributeProvider provider, AttributeType type)
 300                 {
 301                         if (HasSecurityAttribute (provider, type))
 302                                 return;
 303
 304                         var attributes = provider.CustomAttributes;
 305                         switch (type) {
 306                         case AttributeType.Critical:
 307                                 attributes.Add (CreateCriticalAttribute ());
 308                                 break;
 309                         case AttributeType.SafeCritical:
 310                                 attributes.Add (CreateSafeCriticalAttribute ());
 311                                 break;
 312                         }
 313                 }
 314
 315                 protected static bool HasSecurityAttribute (ICustomAttributeProvider provider, AttributeType type)
 316                 {
 317                         if (!provider.HasCustomAttributes)
 318                                 return false;
 319
 320                         foreach (CustomAttribute attribute in provider.CustomAttributes) {
 321                                 switch (attribute.Constructor.DeclaringType.Name) {
 322                                 case _critical:
 323                                         if (type == AttributeType.Critical)
 324                                                 return true;
 325
 326                                         break;
 327                                 case _safe_critical:
 328                                         if (type == AttributeType.SafeCritical)
 329                                                 return true;
 330
 331                                         break;
 332                                 }
 333                         }
 334
 335                         return false;
 336                 }
 337
 338                 ICustomAttributeProvider GetTarget (TargetKind kind, string target)
 339                 {
 340                         switch (kind) {
 341                         case TargetKind.Type:
 342                                 return GetType (target);
 343                         case TargetKind.Method:
 344                                 return GetMethod (target);
 345                         default:
 346                                 throw new ArgumentException ();
 347                         }
 348                 }
 349
 350                 TypeDefinition GetType (string fullname)
 351                 {
 352                         return _assembly.MainModule.GetType (fullname);
 353                 }
 354
 355                 MethodDefinition GetMethod (string signature)
 356                 {
 357                         int pos = signature.IndexOf (" ");
 358                         if (pos == -1)
 359                                 throw new ArgumentException ();
 360
 361                         string tmp = signature.Substring (pos + 1);
 362
 363                         pos = tmp.IndexOf ("::");
 364                         if (pos == -1)
 365                                 throw new ArgumentException ();
 366
 367                         string type_name = tmp.Substring (0, pos);
 368
 369                         int parpos = tmp.IndexOf ("(");
 370                         if (parpos == -1)
 371                                 throw new ArgumentException ();
 372
 373                         string method_name = tmp.Substring (pos + 2, parpos - pos - 2);
 374
 375                         TypeDefinition type = GetType (type_name);
 376                         if (type == null)
 377                                 return null;
 378
 379                         return GetMethod (type.Methods, signature);
 380                 }
 381
 382                 static MethodDefinition GetMethod (IEnumerable methods, string signature)
 383                 {
 384                         foreach (MethodDefinition method in methods)
 385                                 if (GetFullName (method) == signature)
 386                                         return method;
 387
 388                         return null;
 389                 }
 390
 391                 static string GetFullName (MethodReference method)
 392                 {
 393                         var sentinel = method.Parameters.FirstOrDefault (p => p.ParameterType.IsSentinel);
 394                         var sentinel_pos = -1;
 395                         if (sentinel != null)
 396                                 sentinel_pos = method.Parameters.IndexOf (sentinel);
 397
 398                         StringBuilder sb = new StringBuilder ();
 399                         sb.Append (method.ReturnType.FullName);
 400                         sb.Append (" ");
 401                         sb.Append (method.DeclaringType.FullName);
 402                         sb.Append ("::");
 403                         sb.Append (method.Name);
 404                         if (method.HasGenericParameters) {
 405                                 sb.Append ("<");
 406                                 for (int i = 0; i < method.GenericParameters.Count; i++ ) {
 407                                         if (i > 0)
 408                                                 sb.Append (",");
 409                                         sb.Append (method.GenericParameters [i].Name);
 410                                 }
 411                                 sb.Append (">");
 412                         }
 413                         sb.Append ("(");
 414                         if (method.HasParameters) {
 415                                 for (int i = 0; i < method.Parameters.Count; i++) {
 416                                         if (i > 0)
 417                                                 sb.Append (",");
 418
 419                                         if (i == sentinel_pos)
 420                                                 sb.Append ("...,");
 421
 422                                         sb.Append (method.Parameters [i].ParameterType.FullName);
 423                                 }
 424                         }
 425                         sb.Append (")");
 426                         return sb.ToString ();
 427                 }
 428
 429                 static MethodDefinition GetDefaultConstructor (TypeDefinition type)
 430                 {
 431                         foreach (MethodDefinition ctor in type.Methods.Where (m => m.IsConstructor))
 432                                 if (!ctor.IsStatic && !ctor.HasParameters)
 433                                         return ctor;
 434
 435                         return null;
 436                 }
 437
 438                 MethodDefinition GetSafeCriticalCtor ()
 439                 {
 440                         if (_safe_critical_ctor != null)
 441                                 return _safe_critical_ctor;
 442
 443                         TypeDefinition safe_critical_type = Context.GetType (_safe_critical);
 444                         if (safe_critical_type == null)
 445                                 throw new InvalidOperationException (String.Format ("{0} type not found", _safe_critical));
 446
 447                         _safe_critical_ctor = GetDefaultConstructor (safe_critical_type);
 448                         return _safe_critical_ctor;
 449                 }
 450
 451                 MethodDefinition GetCriticalCtor ()
 452                 {
 453                         if (_critical_ctor != null)
 454                                 return _critical_ctor;
 455
 456                         TypeDefinition critical_type = Context.GetType (_critical);
 457                         if (critical_type == null)
 458                                 throw new InvalidOperationException (String.Format ("{0} type not found", _critical));
 459
 460                         _critical_ctor = GetDefaultConstructor (critical_type);
 461                         return _critical_ctor;
 462                 }
 463
 464                 TypeDefinition GetSystemVoid ()
 465                 {
 466                         if (_void_type != null)
 467                                 return _void_type;
 468
 469                         _void_type = Context.GetType (_system_void);
 470                         if (_void_type == null)
 471                                 throw new InvalidOperationException (String.Format ("{0} type not found", _system_void));
 472
 473                         return _void_type;
 474                 }
 475
 476                 MethodReference Import (MethodDefinition method)
 477                 {
 478                         return _assembly.MainModule.Import (method);
 479                 }
 480
 481                 CustomAttribute CreateSafeCriticalAttribute ()
 482                 {
 483                         return new CustomAttribute (Import (GetSafeCriticalCtor ()));
 484                 }
 485
 486                 CustomAttribute CreateCriticalAttribute ()
 487                 {
 488                         return new CustomAttribute (Import (GetCriticalCtor ()));
 489                 }
 490
 491                 MethodDefinition CreateDefaultConstructor ()
 492                 {
 493                         MethodDefinition method = new MethodDefinition (".ctor",
 494                                 MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName,
 495                                 GetSystemVoid ());
 496                         method.Body.Instructions.Add (Instruction.Create (OpCodes.Ret));
 497                         return method;
 498                 }
 499         }
 500 }