de4dot-cex/de4dot.code/deobfuscators/Agile_NET/ProxyCallFixer.cs
2014-03-11 22:15:43 +01:00

86 lines
2.8 KiB
C#

/*
Copyright (C) 2011-2014 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 System;
using System.Collections.Generic;
using dnlib.DotNet;
using dnlib.DotNet.Emit;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.Agile_NET {
class ProxyCallFixer : ProxyCallFixer1 {
public ProxyCallFixer(ModuleDefMD module)
: base(module) {
}
public ProxyCallFixer(ModuleDefMD module, ProxyCallFixer oldOne)
: base(module) {
foreach (var method in oldOne.delegateCreatorMethods)
SetDelegateCreatorMethod(Lookup(method, "Could not find delegate creator method"));
}
public void FindDelegateCreator() {
foreach (var type in module.Types) {
var methodName = "System.Void " + type.FullName + "::icgd(System.Int32)";
foreach (var method in type.Methods) {
if (method.FullName == methodName) {
SetDelegateCreatorMethod(method);
return;
}
}
}
}
protected override object CheckCctor(ref TypeDef type, MethodDef cctor) {
var instrs = cctor.Body.Instructions;
if (instrs.Count != 3)
return null;
if (!instrs[0].IsLdcI4())
return null;
if (instrs[1].OpCode != OpCodes.Call || !IsDelegateCreatorMethod(instrs[1].Operand as MethodDef))
return null;
if (instrs[2].OpCode != OpCodes.Ret)
return null;
int delegateToken = 0x02000001 + instrs[0].GetLdcI4Value();
if (type.MDToken.ToInt32() != delegateToken) {
Logger.w("Delegate token is not current type");
return null;
}
return new object();
}
protected override void GetCallInfo(object context, FieldDef field, out IMethod calledMethod, out OpCode callOpcode) {
var name = field.Name.String;
callOpcode = OpCodes.Call;
if (name.EndsWith("%", StringComparison.Ordinal)) {
callOpcode = OpCodes.Callvirt;
name = name.TrimEnd(new char[] { '%' });
}
byte[] value = Convert.FromBase64String(name);
int methodIndex = BitConverter.ToInt32(value, 0); // 0-based memberRef index
var mr = module.ResolveMemberRef((uint)methodIndex + 1);
if (mr == null || !mr.IsMethodRef)
throw new ApplicationException(string.Format("Invalid MemberRef index: {0}", methodIndex));
calledMethod = mr;
}
}
}