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Inline short methods (for DNR)

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This commit is contained in:
de4dot 2011-10-24 12:45:20 +02:00
parent 46309f2f78
commit 4d5d1b9089
5 changed files with 248 additions and 45 deletions
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61
blocks/DotNetUtils.cs
View File

@ -357,6 +357,15 @@ namespace de4dot.blocks {
return null;
}
public static Instruction clone(Instruction instr) {
return new Instruction {
Offset = instr.Offset,
OpCode = instr.OpCode,
Operand = instr.Operand,
SequencePoint = instr.SequencePoint,
};
}
public static void copyBody(MethodDefinition method, out IList<Instruction> instructions, out IList<ExceptionHandler> exceptionHandlers) {
if (method == null || !method.HasBody) {
instructions = new List<Instruction>();
@ -370,15 +379,8 @@ namespace de4dot.blocks {
exceptionHandlers = new List<ExceptionHandler>(oldExHandlers.Count);
var oldToIndex = Utils.createObjectToIndexDictionary(oldInstrs);
foreach (var oldInstr in oldInstrs) {
var newInstr = new Instruction {
Offset = oldInstr.Offset,
OpCode = oldInstr.OpCode,
Operand = oldInstr.Operand,
SequencePoint = oldInstr.SequencePoint,
};
instructions.Add(newInstr);
}
foreach (var oldInstr in oldInstrs)
instructions.Add(clone(oldInstr));
foreach (var newInstr in instructions) {
var operand = newInstr.Operand;
@ -614,5 +616,46 @@ namespace de4dot.blocks {
return scope.Name == assemblySimpleName ||
scope.Name.StartsWith(assemblySimpleName + ",", StringComparison.Ordinal);
}
public static int getArgIndex(MethodReference method, Instruction instr) {
switch (instr.OpCode.Code) {
case Code.Ldarg_0: return 0;
case Code.Ldarg_1: return 1;
case Code.Ldarg_2: return 2;
case Code.Ldarg_3: return 3;
case Code.Ldarga:
case Code.Ldarga_S:
case Code.Ldarg:
case Code.Ldarg_S:
return getArgIndex(method, instr.Operand as ParameterDefinition);
}
return -1;
}
public static int getArgIndex(MethodReference method, ParameterDefinition arg) {
if (arg == null)
return -1;
if (method.HasThis)
return arg.Index + 1;
return arg.Index;
}
public static List<TypeReference> getArgs(MethodReference method) {
var args = new List<TypeReference>(method.Parameters.Count + 1);
if (method.HasThis)
args.Add(method.DeclaringType);
foreach (var arg in method.Parameters)
args.Add(arg.ParameterType);
return args;
}
public static int getArgsCount(MethodReference method) {
int count = method.Parameters.Count;
if (method.HasThis)
count++;
return count;
}
}
}

1
blocks/blocks.csproj
View File

@ -42,6 +42,7 @@
<Compile Include="cflow\InstructionEmulator.cs" />
<Compile Include="cflow\Int32Value.cs" />
<Compile Include="cflow\Int64Value.cs" />
<Compile Include="cflow\MethodCallInliner.cs" />
<Compile Include="cflow\Real8Value.cs" />
<Compile Include="cflow\StLdlocFixer.cs" />
<Compile Include="cflow\SwitchCflowDeobfuscator.cs" />

36
blocks/cflow/BlockCflowDeobfuscator.cs
View File

@ -40,8 +40,6 @@ namespace de4dot.blocks.cflow {
return false;
for (int i = 0; i < instructions.Count - 1; i++) {
var instr = instructions[i].Instruction;
if (patchBoolCallMethod(instr, i))
instr = instructions[i].Instruction;
instructionEmulator.emulate(instr);
}
@ -77,40 +75,6 @@ namespace de4dot.blocks.cflow {
}
}
// This is a hack for .NET Reactor
bool patchBoolCallMethod(Instruction instr, int instrIndex) {
if (instr.OpCode.Code != Code.Call)
return false;
var method = instr.Operand as MethodDefinition;
if (method == null)
return false;
if (method.Parameters.Count > 0)
return false;
if (!method.IsStatic)
return false;
if (!MemberReferenceHelper.verifyType(method.MethodReturnType.ReturnType, "mscorlib", "System.Boolean"))
return false;
var body = method.Body;
if (body == null)
return false;
var instrs = body.Instructions;
if (instrs.Count > 10)
return false;
var ldci4 = instrs[0];
if (ldci4.OpCode.Code == Code.Br || ldci4.OpCode.Code == Code.Br_S)
ldci4 = (Instruction)ldci4.Operand;
if (ldci4 == null || !DotNetUtils.isLdcI4(ldci4) || ldci4.Next == null || ldci4.Next.OpCode.Code != Code.Ret)
return false;
if (!MemberReferenceHelper.compareTypes(method.DeclaringType, blocks.Method.DeclaringType))
return false;
int val = DotNetUtils.getLdcI4Value(ldci4);
block.Instructions[instrIndex] = new Instr(Instruction.Create(OpCodes.Ldc_I4, val));
return true;
}
bool emulateBranch(int stackArgs, Bool3 cond) {
if (cond == Bool3.Unknown)
return false;

6
blocks/cflow/BlocksCflowDeobfuscator.cs
View File

@ -29,6 +29,7 @@ namespace de4dot.blocks.cflow {
DeadCodeRemover deadCodeRemover = new DeadCodeRemover();
DeadStoreRemover deadStoreRemover = new DeadStoreRemover();
StLdlocFixer stLdlocFixer = new StLdlocFixer();
MethodCallInliner methodCallInliner = new MethodCallInliner();
public void init(Blocks blocks) {
this.blocks = blocks;
@ -48,6 +49,11 @@ namespace de4dot.blocks.cflow {
if (iterations == 0)
changed |= fixDotfuscatorLoop();
foreach (var block in allBlocks) {
methodCallInliner.init(blocks, block);
changed |= methodCallInliner.deobfuscate();
}
foreach (var block in allBlocks) {
var lastInstr = block.LastInstr;
if (!DotNetUtils.isConditionalBranch(lastInstr.OpCode.Code) && lastInstr.OpCode.Code != Code.Switch)

189
blocks/cflow/MethodCallInliner.cs Normal file
View File

@ -0,0 +1,189 @@
/*
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;
namespace de4dot.blocks.cflow {
class MethodCallInliner {
Blocks blocks;
Block block;
public void init(Blocks blocks, Block block) {
this.blocks = blocks;
this.block = block;
}
public bool deobfuscate() {
bool changed = false;
var instructions = block.Instructions;
for (int i = 0; i < instructions.Count; i++) {
var instr = instructions[i].Instruction;
if (instr.OpCode.Code == Code.Call)
changed |= inlineMethod(instr, i);
}
return changed;
}
bool inlineMethod(Instruction callInstr, int instrIndex) {
var method = callInstr.Operand as MethodDefinition;
if (method == null)
return false;
if (!method.IsStatic)
return false;
var body = method.Body;
if (body == null)
return false;
if (!MemberReferenceHelper.compareTypes(method.DeclaringType, blocks.Method.DeclaringType))
return false;
int index = 0;
var instr = getInstruction(body.Instructions, ref index);
if (instr == null)
return false;
switch (instr.OpCode.Code) {
case Code.Ldarg:
case Code.Ldarg_S:
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
case Code.Call:
return inlineOtherMethod(instrIndex, method, instr, index);
case Code.Ldc_I4:
case Code.Ldc_I4_0:
case Code.Ldc_I4_1:
case Code.Ldc_I4_2:
case Code.Ldc_I4_3:
case Code.Ldc_I4_4:
case Code.Ldc_I4_5:
case Code.Ldc_I4_6:
case Code.Ldc_I4_7:
case Code.Ldc_I4_8:
case Code.Ldc_I4_M1:
case Code.Ldc_I4_S:
case Code.Ldc_I8:
case Code.Ldc_R4:
case Code.Ldc_R8:
case Code.Ldftn:
case Code.Ldnull:
case Code.Ldstr:
case Code.Ldtoken:
case Code.Ldsfld:
case Code.Ldsflda:
return inlineLoadMethod(instrIndex, method, instr, index);
default:
return false;
}
}
bool inlineLoadMethod(int patchIndex, MethodDefinition method, Instruction loadInstr, int instrIndex) {
var instr = getInstruction(method.Body.Instructions, ref instrIndex);
if (instr == null || instr.OpCode.Code != Code.Ret)
return false;
int methodArgsCount = DotNetUtils.getArgsCount(method);
for (int i = 0; i < methodArgsCount; i++)
block.insert(patchIndex++, Instruction.Create(OpCodes.Pop));
block.Instructions[patchIndex] = new Instr(DotNetUtils.clone(loadInstr));
return true;
}
bool inlineOtherMethod(int patchIndex, MethodDefinition method, Instruction instr, int instrIndex) {
int loadIndex = 0;
int methodArgsCount = (method.HasThis ? 1 : 0) + method.Parameters.Count;
while (instr != null && loadIndex < methodArgsCount) {
switch (instr.OpCode.Code) {
case Code.Ldarg:
case Code.Ldarg_S:
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
if (DotNetUtils.getArgIndex(method, instr) != loadIndex)
return false;
loadIndex++;
instr = getInstruction(method.Body.Instructions, ref instrIndex);
continue;
}
break;
}
if (instr == null || loadIndex != methodArgsCount)
return false;
if (instr.OpCode.Code != Code.Call && instr.OpCode.Code != Code.Callvirt)
return false;
var callInstr = instr;
var calledMethod = callInstr.Operand as MethodReference;
if (calledMethod == null)
return false;
if (!isCompatibleType(calledMethod.MethodReturnType.ReturnType, method.MethodReturnType.ReturnType))
return false;
var methodArgs = DotNetUtils.getArgs(method);
var calledMethodArgs = DotNetUtils.getArgs(calledMethod);
if (methodArgs.Count != calledMethodArgs.Count)
return false;
for (int i = 0; i < methodArgs.Count; i++) {
if (!isCompatibleType(calledMethodArgs[i], methodArgs[i]))
return false;
}
instr = getInstruction(method.Body.Instructions, ref instrIndex);
if (instr == null || instr.OpCode.Code != Code.Ret)
return false;
block.Instructions[patchIndex] = new Instr(DotNetUtils.clone(callInstr));
return true;
}
static bool isCompatibleType(TypeReference origType, TypeReference newType) {
if (MemberReferenceHelper.compareTypes(origType, newType))
return true;
if (newType.IsValueType || origType.IsValueType)
return false;
return newType.FullName == "System.Object";
}
static Instruction getInstruction(IList<Instruction> instructions, ref int index) {
for (int i = 0; i < 10; i++) {
if (index < 0 || index >= instructions.Count)
return null;
var instr = instructions[index++];
if (instr.OpCode.Code == Code.Nop)
continue;
if (instr == null || (instr.OpCode.Code != Code.Br && instr.OpCode.Code != Code.Br_S))
return instr;
instr = instr.Operand as Instruction;
if (instr == null)
return null;
index = instructions.IndexOf(instr);
if (index < 0)
return null;
}
return null;
}
}
}