327 lines
9.2 KiB
C#
327 lines
9.2 KiB
C#
/*
|
|
Copyright (C) 2011-2012 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.Collections.Generic;
|
|
using Mono.Cecil;
|
|
using Mono.Cecil.Cil;
|
|
using Mono.Cecil.Metadata;
|
|
using de4dot.blocks;
|
|
using de4dot.blocks.cflow;
|
|
|
|
namespace de4dot.code.deobfuscators.DeepSea {
|
|
class ArrayBlockDeobfuscator : BlockDeobfuscator {
|
|
ModuleDefinition module;
|
|
FieldDefinitionAndDeclaringTypeDict<FieldInfo> fieldToInfo = new FieldDefinitionAndDeclaringTypeDict<FieldInfo>();
|
|
Dictionary<VariableDefinition, FieldInfo> localToInfo = new Dictionary<VariableDefinition, FieldInfo>();
|
|
DsConstantsReader constantsReader;
|
|
|
|
class FieldInfo {
|
|
public readonly FieldDefinition field;
|
|
public readonly FieldDefinition arrayInitField;
|
|
public readonly byte[] array;
|
|
|
|
public FieldInfo(FieldDefinition field, FieldDefinition arrayInitField) {
|
|
this.field = field;
|
|
this.arrayInitField = arrayInitField;
|
|
this.array = (byte[])arrayInitField.InitialValue.Clone();
|
|
}
|
|
}
|
|
|
|
public bool Detected {
|
|
get { return fieldToInfo.Count != 0; }
|
|
}
|
|
|
|
public ArrayBlockDeobfuscator(ModuleDefinition module) {
|
|
this.module = module;
|
|
}
|
|
|
|
public void init() {
|
|
initializeArrays(DotNetUtils.getModuleTypeCctor(module));
|
|
}
|
|
|
|
void initializeArrays(MethodDefinition method) {
|
|
if (method == null || method.Body == null)
|
|
return;
|
|
|
|
var instructions = method.Body.Instructions;
|
|
for (int i = 0; i < instructions.Count; i++) {
|
|
var ldci4 = instructions[i];
|
|
if (!DotNetUtils.isLdcI4(ldci4))
|
|
continue;
|
|
i++;
|
|
var instrs = DotNetUtils.getInstructions(instructions, i, OpCodes.Newarr, OpCodes.Dup, OpCodes.Ldtoken, OpCodes.Call, OpCodes.Stsfld);
|
|
if (instrs == null)
|
|
continue;
|
|
|
|
var arrayType = instrs[0].Operand as TypeReference;
|
|
if (arrayType == null || arrayType.EType != ElementType.U1)
|
|
continue;
|
|
|
|
var arrayInitField = instrs[2].Operand as FieldDefinition;
|
|
if (arrayInitField == null || arrayInitField.InitialValue == null || arrayInitField.InitialValue.Length == 0)
|
|
continue;
|
|
|
|
var calledMethod = instrs[3].Operand as MethodReference;
|
|
if (calledMethod == null || calledMethod.FullName != "System.Void System.Runtime.CompilerServices.RuntimeHelpers::InitializeArray(System.Array,System.RuntimeFieldHandle)")
|
|
continue;
|
|
|
|
var targetField = instrs[4].Operand as FieldDefinition;
|
|
if (targetField == null)
|
|
continue;
|
|
|
|
fieldToInfo.add(targetField, new FieldInfo(targetField, arrayInitField));
|
|
}
|
|
}
|
|
|
|
public override void deobfuscateBegin(Blocks blocks) {
|
|
base.deobfuscateBegin(blocks);
|
|
initLocalToInfo();
|
|
}
|
|
|
|
void initLocalToInfo() {
|
|
localToInfo.Clear();
|
|
|
|
foreach (var block in blocks.MethodBlocks.getAllBlocks()) {
|
|
var instrs = block.Instructions;
|
|
for (int i = 0; i < instrs.Count - 1; i++) {
|
|
var ldsfld = instrs[i];
|
|
if (ldsfld.OpCode.Code != Code.Ldsfld)
|
|
continue;
|
|
var stloc = instrs[i + 1];
|
|
if (!stloc.isStloc())
|
|
continue;
|
|
|
|
var info = fieldToInfo.find((FieldReference)ldsfld.Operand);
|
|
if (info == null)
|
|
continue;
|
|
var local = DotNetUtils.getLocalVar(blocks.Locals, stloc.Instruction);
|
|
if (local == null)
|
|
continue;
|
|
|
|
localToInfo[local] = info;
|
|
}
|
|
}
|
|
}
|
|
|
|
protected override bool deobfuscate(Block block) {
|
|
bool changed = false;
|
|
|
|
constantsReader = null;
|
|
var instrs = block.Instructions;
|
|
for (int i = 0; i < instrs.Count; i++) {
|
|
bool ch = deobfuscate1(block, i);
|
|
if (ch) {
|
|
changed = true;
|
|
continue;
|
|
}
|
|
|
|
ch = deobfuscate2(block, i);
|
|
if (ch) {
|
|
changed = true;
|
|
continue;
|
|
}
|
|
|
|
ch = deobfuscate3(block, i);
|
|
if (ch) {
|
|
changed = true;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
return changed;
|
|
}
|
|
|
|
bool deobfuscate1(Block block, int i) {
|
|
var instrs = block.Instructions;
|
|
if (i >= instrs.Count - 2)
|
|
return false;
|
|
|
|
var ldloc = instrs[i];
|
|
if (!ldloc.isLdloc())
|
|
return false;
|
|
var local = DotNetUtils.getLocalVar(blocks.Locals, ldloc.Instruction);
|
|
if (local == null)
|
|
return false;
|
|
FieldInfo info;
|
|
if (!localToInfo.TryGetValue(local, out info))
|
|
return false;
|
|
|
|
var ldci4 = instrs[i + 1];
|
|
if (!ldci4.isLdcI4())
|
|
return false;
|
|
|
|
var ldelem = instrs[i + 2];
|
|
if (ldelem.OpCode.Code != Code.Ldelem_U1)
|
|
return false;
|
|
|
|
block.remove(i, 3 - 1);
|
|
instrs[i] = new Instr(DotNetUtils.createLdci4(info.array[ldci4.getLdcI4Value()]));
|
|
return true;
|
|
}
|
|
|
|
bool deobfuscate2(Block block, int i) {
|
|
var instrs = block.Instructions;
|
|
if (i >= instrs.Count - 2)
|
|
return false;
|
|
|
|
var ldsfld = instrs[i];
|
|
if (ldsfld.OpCode.Code != Code.Ldsfld)
|
|
return false;
|
|
var info = fieldToInfo.find(ldsfld.Operand as FieldReference);
|
|
if (info == null)
|
|
return false;
|
|
|
|
var ldci4 = instrs[i + 1];
|
|
if (!ldci4.isLdcI4())
|
|
return false;
|
|
|
|
var ldelem = instrs[i + 2];
|
|
if (ldelem.OpCode.Code != Code.Ldelem_U1)
|
|
return false;
|
|
|
|
block.remove(i, 3 - 1);
|
|
instrs[i] = new Instr(DotNetUtils.createLdci4(info.array[ldci4.getLdcI4Value()]));
|
|
return true;
|
|
}
|
|
|
|
bool deobfuscate3(Block block, int i) {
|
|
var instrs = block.Instructions;
|
|
if (i + 1 >= instrs.Count)
|
|
return false;
|
|
|
|
int start = i;
|
|
var ldsfld = instrs[i];
|
|
if (ldsfld.OpCode.Code != Code.Ldsfld)
|
|
return false;
|
|
var info = fieldToInfo.find(ldsfld.Operand as FieldReference);
|
|
if (info == null)
|
|
return false;
|
|
|
|
if (!instrs[i + 1].isLdcI4())
|
|
return false;
|
|
|
|
var constants = getConstantsReader(block);
|
|
int value;
|
|
i += 2;
|
|
if (!constants.getInt32(ref i, out value))
|
|
return false;
|
|
|
|
if (i >= instrs.Count)
|
|
return false;
|
|
var stelem = instrs[i];
|
|
if (stelem.OpCode.Code != Code.Stelem_I1)
|
|
return false;
|
|
|
|
block.remove(start, i - start + 1);
|
|
return true;
|
|
}
|
|
|
|
DsConstantsReader getConstantsReader(Block block) {
|
|
if (constantsReader != null)
|
|
return constantsReader;
|
|
return constantsReader = new DsConstantsReader(block.Instructions);
|
|
}
|
|
|
|
public IEnumerable<FieldDefinition> cleanUp() {
|
|
var removedFields = new List<FieldDefinition>();
|
|
var moduleCctor = DotNetUtils.getModuleTypeCctor(module);
|
|
if (moduleCctor == null)
|
|
return removedFields;
|
|
var moduleCctorBlocks = new Blocks(moduleCctor);
|
|
|
|
var keep = findFieldsToKeep();
|
|
foreach (var fieldInfo in fieldToInfo.getValues()) {
|
|
if (keep.ContainsKey(fieldInfo))
|
|
continue;
|
|
if (removeInitCode(moduleCctorBlocks, fieldInfo)) {
|
|
removedFields.Add(fieldInfo.field);
|
|
removedFields.Add(fieldInfo.arrayInitField);
|
|
}
|
|
fieldInfo.arrayInitField.InitialValue = new byte[1];
|
|
fieldInfo.arrayInitField.FieldType = module.TypeSystem.Byte;
|
|
}
|
|
|
|
IList<Instruction> allInstructions;
|
|
IList<ExceptionHandler> allExceptionHandlers;
|
|
moduleCctorBlocks.getCode(out allInstructions, out allExceptionHandlers);
|
|
DotNetUtils.restoreBody(moduleCctorBlocks.Method, allInstructions, allExceptionHandlers);
|
|
return removedFields;
|
|
}
|
|
|
|
bool removeInitCode(Blocks blocks, FieldInfo info) {
|
|
bool removedSomething = false;
|
|
foreach (var block in blocks.MethodBlocks.getAllBlocks()) {
|
|
var instrs = block.Instructions;
|
|
for (int i = 0; i < instrs.Count - 5; i++) {
|
|
var ldci4 = instrs[i];
|
|
if (!ldci4.isLdcI4())
|
|
continue;
|
|
if (instrs[i + 1].OpCode.Code != Code.Newarr)
|
|
continue;
|
|
if (instrs[i + 2].OpCode.Code != Code.Dup)
|
|
continue;
|
|
var ldtoken = instrs[i + 3];
|
|
if (ldtoken.OpCode.Code != Code.Ldtoken)
|
|
continue;
|
|
if (ldtoken.Operand != info.arrayInitField)
|
|
continue;
|
|
var call = instrs[i + 4];
|
|
if (call.OpCode.Code != Code.Call)
|
|
continue;
|
|
var calledMethod = call.Operand as MethodReference;
|
|
if (calledMethod == null || calledMethod.FullName != "System.Void System.Runtime.CompilerServices.RuntimeHelpers::InitializeArray(System.Array,System.RuntimeFieldHandle)")
|
|
continue;
|
|
var stsfld = instrs[i + 5];
|
|
if (stsfld.OpCode.Code != Code.Stsfld)
|
|
continue;
|
|
if (stsfld.Operand != info.field)
|
|
continue;
|
|
block.remove(i, 6);
|
|
i--;
|
|
removedSomething = true;
|
|
}
|
|
}
|
|
return removedSomething;
|
|
}
|
|
|
|
Dictionary<FieldInfo, bool> findFieldsToKeep() {
|
|
var keep = new Dictionary<FieldInfo, bool>();
|
|
foreach (var type in module.GetTypes()) {
|
|
foreach (var method in type.Methods) {
|
|
if (type == DotNetUtils.getModuleType(module) && method.Name == ".cctor")
|
|
continue;
|
|
if (method.Body == null)
|
|
continue;
|
|
|
|
foreach (var instr in method.Body.Instructions) {
|
|
var field = instr.Operand as FieldReference;
|
|
if (field == null)
|
|
continue;
|
|
var fieldInfo = fieldToInfo.find(field);
|
|
if (fieldInfo == null)
|
|
continue;
|
|
keep[fieldInfo] = true;
|
|
}
|
|
}
|
|
}
|
|
return keep;
|
|
}
|
|
}
|
|
}
|