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Move array finder code to a new ArrayFinder class

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This commit is contained in:
de4dot 2011-10-29 03:38:09 +02:00
parent 0a8d772c22
commit def4072bc5
3 changed files with 149 additions and 65 deletions
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1
de4dot.code/de4dot.code.csproj
View File

@ -69,6 +69,7 @@
<Compile Include="deobfuscators\DeobfuscatorInfoBase.cs" />
<Compile Include="deobfuscators\DeobUtils.cs" />
<Compile Include="deobfuscators\Dotfuscator\Deobfuscator.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\ArrayFinder.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\BooleanDecrypter.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\BoolValueInliner.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\Deobfuscator.cs" />

146
de4dot.code/deobfuscators/dotNET_Reactor/ArrayFinder.cs Normal file
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@ -0,0 +1,146 @@
/*
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 System.Collections.Generic;
using Mono.Cecil;
using Mono.Cecil.Cil;
using de4dot.blocks;
using de4dot.blocks.cflow;
namespace de4dot.deobfuscators.dotNET_Reactor {
class ArrayFinder {
List<byte[]> arrays = new List<byte[]>();
public ArrayFinder(MethodDefinition method) {
init(method);
}
void init(MethodDefinition method) {
if (method.Body == null)
return;
foreach (var instr in method.Body.Instructions) {
if (instr.OpCode.Code != Code.Ldtoken)
continue;
var field = instr.Operand as FieldDefinition;
if (field == null)
continue;
arrays.Add(field.InitialValue);
}
var instructions = method.Body.Instructions;
for (int i = 1; i < instructions.Count; i++) {
var instr = instructions[i];
if (instr.OpCode.Code != Code.Newarr)
continue;
var ldci4 = instructions[i - 1];
if (!DotNetUtils.isLdcI4(ldci4))
continue;
int arraySize = DotNetUtils.getLdcI4Value(ldci4);
var ary = getInitializedArray(arraySize, method, ref i);
if (ary != null)
arrays.Add(ary);
}
}
public bool exists(byte[] array) {
foreach (var ary in arrays) {
if (isEqual(ary, array))
return true;
}
return false;
}
static bool isEqual(byte[] ary1, byte[] ary2) {
if (ary1.Length != ary2.Length)
return false;
for (int i = 0; i < ary1.Length; i++) {
if (ary1[i] != ary2[i])
return false;
}
return true;
}
public static byte[] getInitializedArray(MethodDefinition method, int arraySize) {
int newarrIndex = findNewarr(method, arraySize);
if (newarrIndex < 0)
return null;
return getInitializedArray(arraySize, method, ref newarrIndex);
}
public static byte[] getInitializedArray(int arraySize, MethodDefinition method, ref int newarrIndex) {
var resultValueArray = new Value[arraySize];
var emulator = new InstructionEmulator(method.HasThis, false, method.Parameters, method.Body.Variables);
var theArray = new UnknownValue();
emulator.push(theArray);
var instructions = method.Body.Instructions;
int i;
for (i = newarrIndex + 1; i < instructions.Count; i++) {
var instr = instructions[i];
if (instr.OpCode.FlowControl != FlowControl.Next)
break;
if (instr.OpCode.Code == Code.Newarr)
break;
if (instr.OpCode.Code == Code.Stelem_I1) {
var value = emulator.pop();
var index = emulator.pop() as Int32Value;
var array = emulator.pop();
if (ReferenceEquals(array, theArray) && index != null && index.allBitsValid()) {
if (0 <= index.value && index.value < resultValueArray.Length)
resultValueArray[index.value] = value;
}
}
else
emulator.emulate(instr);
}
newarrIndex = i;
byte[] resultArray = new byte[resultValueArray.Length];
for (i = 0; i < resultArray.Length; i++) {
var intValue = resultValueArray[i] as Int32Value;
if (intValue == null || !intValue.allBitsValid())
return null;
resultArray[i] = (byte)intValue.value;
}
return resultArray;
}
static int findNewarr(MethodDefinition method, int arraySize) {
var instructions = method.Body.Instructions;
for (int i = 0; i < instructions.Count; i++) {
var instr = instructions[i];
if (instr.OpCode.Code != Code.Newarr || i < 1)
continue;
var ldci4 = instructions[i - 1];
if (!DotNetUtils.isLdcI4(ldci4))
continue;
if (DotNetUtils.getLdcI4Value(ldci4) != arraySize)
continue;
return i;
}
return -1;
}
}
}

67
de4dot.code/deobfuscators/dotNET_Reactor/EncryptedResource.cs
View File

@ -22,9 +22,7 @@ using System.IO;
using System.Collections.Generic;
using System.Security.Cryptography;
using Mono.Cecil;
using Mono.Cecil.Cil;
using de4dot.blocks;
using de4dot.blocks.cflow;
namespace de4dot.deobfuscators.dotNET_Reactor {
class EncryptedResource {
@ -98,10 +96,10 @@ namespace de4dot.deobfuscators.dotNET_Reactor {
if (encryptedDataResource == null)
throw new ApplicationException("Could not find encrypted resource");
key = initArray(resourceDecrypterMethod, 32);
key = ArrayFinder.getInitializedArray(resourceDecrypterMethod, 32);
if (key == null)
throw new ApplicationException("Could not find resource decrypter key");
iv = initArray(resourceDecrypterMethod, 16);
iv = ArrayFinder.getInitializedArray(resourceDecrypterMethod, 16);
if (iv == null)
throw new ApplicationException("Could not find resource decrypter IV");
var publicKeyToken = module.Assembly.Name.PublicKeyToken;
@ -120,67 +118,6 @@ namespace de4dot.deobfuscators.dotNET_Reactor {
return null;
}
static byte[] initArray(MethodDefinition method, int arraySize) {
int newarrIndex = findNewarr(method, arraySize);
if (newarrIndex < 0)
return null;
var resultValueArray = new Value[arraySize];
var emulator = new InstructionEmulator(method.HasThis, false, method.Parameters, method.Body.Variables);
var theArray = new UnknownValue();
emulator.push(theArray);
var instructions = method.Body.Instructions;
for (int i = newarrIndex + 1; i < instructions.Count; i++) {
var instr = instructions[i];
if (instr.OpCode.FlowControl != FlowControl.Next)
break;
if (instr.OpCode.Code == Code.Newarr)
break;
if (instr.OpCode.Code == Code.Stelem_I1) {
var value = emulator.pop();
var index = emulator.pop() as Int32Value;
var array = emulator.pop();
if (ReferenceEquals(array, theArray) && index != null && index.allBitsValid()) {
if (0 <= index.value && index.value < resultValueArray.Length)
resultValueArray[index.value] = value;
}
}
else
emulator.emulate(instr);
}
byte[] resultArray = new byte[resultValueArray.Length];
for (int i = 0; i < resultArray.Length; i++) {
var intValue = resultValueArray[i] as Int32Value;
if (intValue == null || !intValue.allBitsValid())
return null;
resultArray[i] = (byte)intValue.value;
}
return resultArray;
}
static int findNewarr(MethodDefinition method, int arraySize) {
var instructions = method.Body.Instructions;
for (int i = 0; i < instructions.Count; i++) {
var instr = instructions[i];
if (instr.OpCode.Code != Code.Newarr || i < 1)
continue;
var ldci4 = instructions[i - 1];
if (!DotNetUtils.isLdcI4(ldci4))
continue;
if (DotNetUtils.getLdcI4Value(ldci4) != arraySize)
continue;
return i;
}
return -1;
}
public byte[] decrypt() {
if (encryptedDataResource == null || key == null || iv == null)
throw new ApplicationException("Can't decrypt resource");