Add code to restore methods' arg types
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651072e2d4
commit
2e2eafdb57
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@ -28,12 +28,25 @@ namespace de4dot.deobfuscators {
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// so it will be a basic implementation only.
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class TypesRestorer {
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ModuleDefinition module;
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List<MethodDefinition> allMethods;
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Dictionary<ParameterDefinition, ArgAccessInfo> argInfos = new Dictionary<ParameterDefinition, ArgAccessInfo>();
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List<ArgAccessInfo> changedArgInfos = new List<ArgAccessInfo>();
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Dictionary<FieldReferenceAndDeclaringTypeKey, FieldWriteInfo> fieldWrites = new Dictionary<FieldReferenceAndDeclaringTypeKey, FieldWriteInfo>();
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class ArgAccessInfo {
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public Dictionary<TypeReferenceKey, bool> types = new Dictionary<TypeReferenceKey, bool>();
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public TypeReference newType = null;
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public ParameterDefinition arg;
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public ArgAccessInfo(ParameterDefinition arg) {
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this.arg = arg;
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}
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}
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class FieldWriteInfo {
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public Dictionary<TypeReferenceKey, bool> types = new Dictionary<TypeReferenceKey, bool>();
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public TypeReference newType = null;
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public FieldDefinition field;
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public TypeReference newFieldType = null;
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public FieldWriteInfo(FieldDefinition field) {
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this.field = field;
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@ -45,6 +58,10 @@ namespace de4dot.deobfuscators {
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}
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public void deobfuscate() {
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allMethods = new List<MethodDefinition>();
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foreach (var type in module.GetTypes())
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allMethods.AddRange(type.Methods);
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foreach (var type in module.GetTypes()) {
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foreach (var field in type.Fields) {
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if (!MemberReferenceHelper.isSystemObject(field.FieldType))
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@ -55,14 +72,322 @@ namespace de4dot.deobfuscators {
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}
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}
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var allMethods = new List<MethodDefinition>();
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foreach (var type in module.GetTypes())
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allMethods.AddRange(type.Methods);
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for (int i = 0; i < 10; i++) {
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if (!updateFields(allMethods))
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bool changed = false;
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changed |= deobfuscateFields();
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changed |= deobfuscateMethods();
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if (!changed)
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break;
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}
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}
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bool deobfuscateMethods() {
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changedArgInfos.Clear();
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foreach (var method in allMethods) {
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deobfuscateMethod(method);
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foreach (var info in argInfos.Values) {
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if (info.types.Count == 0)
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continue;
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TypeReference newType = null;
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foreach (var key in info.types.Keys) {
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if (newType == null) {
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newType = key.TypeReference;
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continue;
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}
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newType = getCommonBaseClass(newType, key.TypeReference);
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if (newType == null)
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break;
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}
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if (newType == null)
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continue;
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if (MemberReferenceHelper.compareTypes(newType, info.newType))
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continue;
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info.newType = newType;
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changedArgInfos.Add(info);
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}
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}
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if (changedArgInfos.Count == 0)
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return false;
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changedArgInfos.Sort((a, b) => {
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if (a.arg.Method.MetadataToken.ToInt32() < b.arg.Method.MetadataToken.ToInt32()) return -1;
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if (a.arg.Method.MetadataToken.ToInt32() > b.arg.Method.MetadataToken.ToInt32()) return 1;
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if (a.arg.Index < b.arg.Index) return -1;
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if (a.arg.Index < b.arg.Index) return 1;
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return 0;
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});
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bool changed = false;
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Log.v("Changing method arg types from object -> real type");
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Log.indent();
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IMethodSignature updatedMethod = null;
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Log.indent();
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foreach (var info in changedArgInfos) {
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if (info.newType == null || MemberReferenceHelper.isSystemObject(info.newType))
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continue;
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if (updatedMethod == null || updatedMethod != info.arg.Method) {
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updatedMethod = info.arg.Method;
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Log.deIndent();
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Log.v("Method {0:X8}", updatedMethod.MetadataToken.ToInt32());
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Log.indent();
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}
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Log.v("{0}: new type: {1} ({2:X8})", info.arg.Index, info.newType, info.newType.MetadataToken.ToInt32());
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info.arg.ParameterType = info.newType;
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changed = true;
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}
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Log.deIndent();
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Log.deIndent();
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return changed;
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}
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void deobfuscateMethod(MethodDefinition method) {
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if (!method.IsStatic || method.Body == null)
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return;
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argInfos.Clear();
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foreach (var arg in method.Parameters) {
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if (arg.ParameterType == null || arg.ParameterType.IsValueType)
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continue;
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if (!MemberReferenceHelper.isSystemObject(arg.ParameterType))
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continue;
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argInfos[arg] = new ArgAccessInfo(arg);
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}
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if (argInfos.Count == 0)
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return;
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var methodParams = DotNetUtils.getParameters(method);
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var reversedMethodParams = new List<ParameterDefinition>(methodParams);
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reversedMethodParams.Reverse();
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List<Instruction> args;
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var instructions = method.Body.Instructions;
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for (int i = 0; i < instructions.Count; i++) {
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var instr = instructions[i];
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switch (instr.OpCode.Code) {
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case Code.Call:
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case Code.Calli:
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case Code.Callvirt:
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args = getPushedArgInstructions(instructions, i);
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var calledMethod = instr.Operand as MethodReference;
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if (calledMethod == null)
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break;
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var calledMethodParams = DotNetUtils.getParameters(calledMethod);
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for (int j = 0; j < args.Count; j++) {
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int calledMethodParamIndex = calledMethodParams.Count - j - 1;
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var ldInstr = args[j];
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switch (ldInstr.OpCode.Code) {
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case Code.Ldarg:
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case Code.Ldarg_S:
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case Code.Ldarg_0:
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case Code.Ldarg_1:
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case Code.Ldarg_2:
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case Code.Ldarg_3:
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addMethodArgType(getParameter(methodParams, method, ldInstr), DotNetUtils.getParameter(calledMethodParams, calledMethodParamIndex));
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break;
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default:
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break;
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}
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}
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break;
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case Code.Castclass:
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args = getPushedArgInstructions(instructions, i);
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if (args.Count < 1)
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break;
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addMethodArgType(getParameter(methodParams, method, args[0]), instr.Operand as TypeReference);
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break;
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case Code.Stloc:
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case Code.Stloc_S:
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case Code.Stloc_0:
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case Code.Stloc_1:
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case Code.Stloc_2:
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case Code.Stloc_3:
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args = getPushedArgInstructions(instructions, i);
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if (args.Count < 1)
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break;
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addMethodArgType(getParameter(methodParams, method, args[0]), DotNetUtils.getLocalVar(method.Body.Variables, instr));
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break;
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case Code.Stsfld:
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args = getPushedArgInstructions(instructions, i);
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if (args.Count < 1)
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break;
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addMethodArgType(getParameter(methodParams, method, args[0]), instr.Operand as FieldReference);
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break;
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case Code.Stfld:
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args = getPushedArgInstructions(instructions, i);
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if (args.Count >= 1) {
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var field = instr.Operand as FieldReference;
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addMethodArgType(getParameter(methodParams, method, args[0]), field);
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if (args.Count >= 2 && field != null)
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addMethodArgType(getParameter(methodParams, method, args[1]), field.DeclaringType);
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}
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break;
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//TODO: For better results, these should be checked:
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case Code.Starg:
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case Code.Starg_S:
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case Code.Ldelema:
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case Code.Ldelem_Any:
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case Code.Ldelem_I:
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case Code.Ldelem_I1:
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case Code.Ldelem_I2:
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case Code.Ldelem_I4:
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case Code.Ldelem_I8:
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case Code.Ldelem_R4:
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case Code.Ldelem_R8:
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case Code.Ldelem_Ref:
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case Code.Ldelem_U1:
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case Code.Ldelem_U2:
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case Code.Ldelem_U4:
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case Code.Ldind_I:
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case Code.Ldind_I1:
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case Code.Ldind_I2:
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case Code.Ldind_I4:
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case Code.Ldind_I8:
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case Code.Ldind_R4:
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case Code.Ldind_R8:
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case Code.Ldind_Ref:
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case Code.Ldind_U1:
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case Code.Ldind_U2:
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case Code.Ldind_U4:
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case Code.Ldobj:
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case Code.Stelem_Any:
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case Code.Stelem_I:
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case Code.Stelem_I1:
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case Code.Stelem_I2:
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case Code.Stelem_I4:
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case Code.Stelem_I8:
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case Code.Stelem_R4:
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case Code.Stelem_R8:
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case Code.Stelem_Ref:
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case Code.Stind_I:
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case Code.Stind_I1:
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case Code.Stind_I2:
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case Code.Stind_I4:
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case Code.Stind_I8:
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case Code.Stind_R4:
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case Code.Stind_R8:
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case Code.Stind_Ref:
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case Code.Stobj:
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default:
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break;
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}
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}
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}
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static ParameterDefinition getParameter(IList<ParameterDefinition> parameters, MethodReference method, Instruction instr) {
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switch (instr.OpCode.Code) {
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case Code.Ldarg:
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case Code.Ldarg_S:
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case Code.Ldarg_0:
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case Code.Ldarg_1:
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case Code.Ldarg_2:
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case Code.Ldarg_3:
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return DotNetUtils.getParameter(parameters, method, instr);
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default:
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return null;
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}
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}
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bool addMethodArgType(ParameterDefinition methodParam, FieldReference field) {
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if (field == null)
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return false;
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return addMethodArgType(methodParam, field.FieldType);
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}
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bool addMethodArgType(ParameterDefinition methodParam, VariableDefinition otherLocal) {
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if (otherLocal == null)
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return false;
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return addMethodArgType(methodParam, otherLocal.VariableType);
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}
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bool addMethodArgType(ParameterDefinition methodParam, ParameterDefinition otherParam) {
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if (otherParam == null)
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return false;
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return addMethodArgType(methodParam, otherParam.ParameterType);
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}
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bool addMethodArgType(ParameterDefinition methodParam, TypeReference type) {
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if (methodParam == null || type == null)
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return false;
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if (type.IsValueType)
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return false;
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if (MemberReferenceHelper.isSystemObject(type))
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return false;
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ArgAccessInfo info;
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if (!argInfos.TryGetValue(methodParam, out info))
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return false;
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var key = new TypeReferenceKey(type);
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if (info.types.ContainsKey(key))
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return false;
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info.types[key] = true;
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return true;
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}
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// May not return all args. The args are returned in reverse order.
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List<Instruction> getPushedArgInstructions(IList<Instruction> instructions, int index) {
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int pushes, pops;
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DotNetUtils.calculateStackUsage(instructions[index], false, out pushes, out pops);
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if (pops == -1)
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return new List<Instruction>();
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return getPushedArgInstructions(instructions, index, pops);
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}
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// May not return all args. The args are returned in reverse order.
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List<Instruction> getPushedArgInstructions(IList<Instruction> instructions, int index, int numArgs) {
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List<Instruction> args = new List<Instruction>(numArgs);
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int skipPushes = 0;
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while (index >= 0 && args.Count < numArgs) {
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var instr = getPreviousInstruction(instructions, ref index);
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if (instr == null)
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break;
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int pushes, pops;
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DotNetUtils.calculateStackUsage(instr, false, out pushes, out pops);
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if (pops == -1)
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break;
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if (pushes > 1)
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break; // dup
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if (skipPushes > 0) {
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skipPushes -= pushes;
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if (skipPushes < 0)
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break;
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skipPushes += pops;
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}
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else {
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if (pushes == 1)
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args.Add(instr);
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skipPushes += pops;
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}
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}
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return args;
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}
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bool deobfuscateFields() {
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if (!updateFields())
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return false;
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var infos = new List<FieldWriteInfo>(fieldWrites.Values);
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infos.Sort((a, b) => {
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@ -74,19 +399,26 @@ namespace de4dot.deobfuscators {
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return 0;
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});
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if (infos.Count == 0)
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return false;
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Log.v("Changing field types from object -> real type");
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Log.indent();
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bool changed = false;
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foreach (var info in infos) {
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if (info.newFieldType == null || MemberReferenceHelper.isSystemObject(info.newFieldType))
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if (info.newType == null || MemberReferenceHelper.isSystemObject(info.newType))
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continue;
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Log.v("{0:X8}: new type: {1} ({2:X8})", info.field.MetadataToken.ToInt32(), info.newFieldType, info.newFieldType.MetadataToken.ToInt32());
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info.field.FieldType = info.newFieldType;
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fieldWrites.Remove(new FieldReferenceAndDeclaringTypeKey(info.field));
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Log.v("{0:X8}: new type: {1} ({2:X8})", info.field.MetadataToken.ToInt32(), info.newType, info.newType.MetadataToken.ToInt32());
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info.field.FieldType = info.newType;
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changed = true;
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}
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Log.deIndent();
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return changed;
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}
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bool updateFields(IEnumerable<MethodDefinition> allMethods) {
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bool updateFields() {
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foreach (var info in fieldWrites.Values)
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info.types.Clear();
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@ -208,10 +540,10 @@ namespace de4dot.deobfuscators {
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}
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if (newType == null)
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continue;
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if (MemberReferenceHelper.compareTypes(newType, info.newFieldType))
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if (MemberReferenceHelper.compareTypes(newType, info.newType))
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continue;
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info.newFieldType = newType;
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info.newType = newType;
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changed = true;
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}
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@ -230,6 +562,8 @@ namespace de4dot.deobfuscators {
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var instr = instructions[instrIndex];
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if (instr.OpCode.Code == Code.Nop)
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continue;
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if (instr.OpCode.OpCodeType == OpCodeType.Prefix)
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continue;
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switch (instr.OpCode.FlowControl) {
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case FlowControl.Next:
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case FlowControl.Call:
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