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Add code to restore ldtoken instructions

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This commit is contained in:
de4dot 2011-11-01 15:17:26 +01:00
parent 4d5c625c78
commit c354ded987
3 changed files with 107 additions and 1 deletions
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1
de4dot.code/de4dot.code.csproj
View File

@ -75,6 +75,7 @@
<Compile Include="deobfuscators\dotNET_Reactor\Deobfuscator.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\EncryptedResource.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\LocalTypes.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\MetadataTokenObfuscator.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\MethodsDecrypter.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\StringDecrypter.cs" />
<Compile Include="deobfuscators\Eazfuscator\Deobfuscator.cs" />

8
de4dot.code/deobfuscators/dotNET_Reactor/Deobfuscator.cs
View File

@ -81,6 +81,7 @@ namespace de4dot.deobfuscators.dotNET_Reactor {
StringDecrypter stringDecrypter;
BooleanDecrypter booleanDecrypter;
BoolValueInliner boolValueInliner;
MetadataTokenObfuscator metadataTokenObfuscator;
bool canRemoveDecrypterType = true;
bool startedDeobfuscating = false;
@ -313,6 +314,8 @@ namespace de4dot.deobfuscators.dotNET_Reactor {
}
DeobfuscatedFile.stringDecryptersAdded();
metadataTokenObfuscator = new MetadataTokenObfuscator(module);
if (Operations.DecryptStrings != OpDecryptString.None)
addResourceToBeRemoved(stringDecrypter.StringsResource, "Encrypted strings");
if (options.DecryptMethods) {
@ -341,6 +344,7 @@ namespace de4dot.deobfuscators.dotNET_Reactor {
}
public override void deobfuscateMethodEnd(Blocks blocks) {
metadataTokenObfuscator.deobfuscate(blocks);
base.deobfuscateMethodEnd(blocks);
}
@ -348,8 +352,10 @@ namespace de4dot.deobfuscators.dotNET_Reactor {
removeInlinedMethods();
if (options.RestoreTypes)
new TypesRestorer(module).deobfuscate();
if (canRemoveDecrypterType && methodsDecrypter.MethodsDecrypterMethod != null)
if (canRemoveDecrypterType && methodsDecrypter.MethodsDecrypterMethod != null) {
addTypeToBeRemoved(methodsDecrypter.MethodsDecrypterMethod.DeclaringType, "Decrypter type");
addTypeToBeRemoved(metadataTokenObfuscator.Type, "Metadata token obfuscator");
}
base.deobfuscateEnd();
}

99
de4dot.code/deobfuscators/dotNET_Reactor/MetadataTokenObfuscator.cs Normal file
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@ -0,0 +1,99 @@
/*
Copyright (C) 2011 de4dot@gmail.com
This file is part of de4dot.
de4dot is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
de4dot is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with de4dot. If not, see <http://www.gnu.org/licenses/>.
*/
using Mono.Cecil;
using Mono.Cecil.Cil;
using de4dot.blocks;
namespace de4dot.deobfuscators.dotNET_Reactor {
// Find the class that returns a RuntimeTypeHandle/RuntimeFieldHandle. The value passed to
// its methods is the original metadata token, which will be different when we save the file.
class MetadataTokenObfuscator {
ModuleDefinition module;
TypeDefinition type;
MethodDefinition typeMethod;
MethodDefinition fieldMethod;
public TypeDefinition Type {
get { return type; }
}
public MetadataTokenObfuscator(ModuleDefinition module) {
this.module = module;
find();
}
void find() {
foreach (var type in module.Types) {
var fields = type.Fields;
if (fields.Count != 1)
continue;
if (fields[0].FieldType.FullName != "System.ModuleHandle")
continue;
if (type.HasProperties || type.HasEvents)
continue;
MethodDefinition fieldMethod = null, typeMethod = null;
foreach (var method in type.Methods) {
if (DotNetUtils.isMethod(method, "System.RuntimeTypeHandle", "(System.Int32)"))
typeMethod = method;
else if (DotNetUtils.isMethod(method, "System.RuntimeFieldHandle", "(System.Int32)"))
fieldMethod = method;
}
if (typeMethod == null || fieldMethod == null)
continue;
this.type = type;
this.typeMethod = typeMethod;
this.fieldMethod = fieldMethod;
return;
}
}
public void deobfuscate(Blocks blocks) {
if (type == null)
return;
foreach (var block in blocks.MethodBlocks.getAllBlocks()) {
var instrs = block.Instructions;
for (int i = 0; i < instrs.Count - 1; i++) {
var instr = instrs[i];
if (instr.OpCode.Code != Code.Ldc_I4)
continue;
var call = instrs[i + 1];
if (call.OpCode.Code != Code.Call)
continue;
var method = call.Operand as MethodReference;
if (!MemberReferenceHelper.compareTypes(type, method.DeclaringType))
continue;
var methodDef = DotNetUtils.getMethod(module, method);
if (methodDef == null)
continue;
if (methodDef != typeMethod && methodDef != fieldMethod)
continue;
int token = (int)instrs[i].Operand;
instrs[i] = new Instr(Instruction.Create(OpCodes.Nop));
instrs[i + 1] = new Instr(new Instruction(OpCodes.Ldtoken, module.LookupToken(token) as MemberReference));
}
}
}
}
}