/*
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 .
*/
using System.Collections.Generic;
using Mono.Cecil;
using Mono.Cecil.Cil;
using Mono.Cecil.Metadata;
using de4dot.blocks;
namespace de4dot.code.deobfuscators {
class ConstantsReader {
protected IInstructions instructions;
protected IList locals;
protected Dictionary localsValuesInt32 = new Dictionary();
protected Dictionary localsValuesInt64 = new Dictionary();
protected Dictionary localsValuesDouble = new Dictionary();
bool emulateConvInstrs;
public interface IInstructions {
int Count { get; }
Instruction this[int index] { get; }
}
class ListInstructions : IInstructions {
IList instrs;
public int Count {
get { return instrs.Count; }
}
public Instruction this[int index] {
get { return instrs[index]; }
}
public ListInstructions(IList instrs) {
this.instrs = instrs;
}
}
class ListInstrs : IInstructions {
IList instrs;
public int Count {
get { return instrs.Count; }
}
public Instruction this[int index] {
get { return instrs[index].Instruction; }
}
public ListInstrs(IList instrs) {
this.instrs = instrs;
}
}
public bool EmulateConvInstructions {
get { return emulateConvInstrs; }
set { emulateConvInstrs = value; }
}
ConstantsReader(IInstructions instructions)
: this(instructions, true) {
}
ConstantsReader(IInstructions instructions, bool emulateConvInstrs) {
this.instructions = instructions;
this.emulateConvInstrs = emulateConvInstrs;
}
public ConstantsReader(IList instrs)
: this(new ListInstructions(instrs)) {
}
public ConstantsReader(IList instrs, bool emulateConvInstrs)
: this(new ListInstructions(instrs), emulateConvInstrs) {
}
public ConstantsReader(IList instrs)
: this(new ListInstrs(instrs)) {
}
public ConstantsReader(IList instrs, bool emulateConvInstrs)
: this(new ListInstrs(instrs), emulateConvInstrs) {
}
public ConstantsReader(MethodDefinition method)
: this(method.Body.Instructions) {
this.locals = method.Body.Variables;
}
public ConstantsReader(IList instrs, IList locals)
: this(instrs) {
this.locals = locals;
}
public void setConstantInt32(VariableDefinition local, int value) {
localsValuesInt32[local] = value;
}
public void setConstantInt32(VariableDefinition local, uint value) {
setConstantInt32(local, (int)value);
}
public void setConstantInt64(VariableDefinition local, long value) {
localsValuesInt64[local] = value;
}
public void setConstantInt64(VariableDefinition local, ulong value) {
setConstantInt64(local, (long)value);
}
public void setConstantDouble(VariableDefinition local, double value) {
localsValuesDouble[local] = value;
}
public bool getNextInt32(ref int index, out int val) {
for (; index < instructions.Count; index++) {
var instr = instructions[index];
if (!isLoadConstantInt32(instr))
continue;
return getInt32(ref index, out val);
}
val = 0;
return false;
}
public bool isLoadConstantInt32(Instruction instr) {
if (DotNetUtils.isLdcI4(instr))
return true;
if (DotNetUtils.isLdloc(instr)) {
int tmp;
return getLocalConstantInt32(instr, out tmp);
}
if (DotNetUtils.isLdarg(instr)) {
int tmp;
return getArgConstantInt32(instr, out tmp);
}
return false;
}
public bool isLoadConstantInt64(Instruction instr) {
if (instr.OpCode.Code == Code.Ldc_I8)
return true;
if (DotNetUtils.isLdloc(instr)) {
long tmp;
return getLocalConstantInt64(instr, out tmp);
}
if (DotNetUtils.isLdarg(instr)) {
long tmp;
return getArgConstantInt64(instr, out tmp);
}
return false;
}
public bool isLoadConstantDouble(Instruction instr) {
if (instr.OpCode.Code == Code.Ldc_R8)
return true;
if (DotNetUtils.isLdloc(instr)) {
double tmp;
return getLocalConstantDouble(instr, out tmp);
}
if (DotNetUtils.isLdarg(instr)) {
double tmp;
return getArgConstantDouble(instr, out tmp);
}
return false;
}
public bool getInt16(ref int index, out short val) {
int tmp;
if (!getInt32(ref index, out tmp)) {
val = 0;
return false;
}
val = (short)tmp;
return true;
}
protected struct ConstantInfo {
public int index;
public T constant;
public ConstantInfo(int index, T constant) {
this.index = index;
this.constant = constant;
}
}
protected virtual bool processInstructionInt32(ref int index, Stack> stack) {
return false;
}
protected virtual bool processInstructionInt64(ref int index, Stack> stack) {
return false;
}
protected virtual bool processInstructionDouble(ref int index, Stack> stack) {
return false;
}
public bool getInt32(ref int index, out int val) {
val = 0;
if (index >= instructions.Count)
return false;
var stack = new Stack>();
int op1;
ConstantInfo info1, info2;
for (; index < instructions.Count; index++) {
if (processInstructionInt32(ref index, stack)) {
index--;
continue;
}
var instr = instructions[index];
switch (instr.OpCode.Code) {
case Code.Conv_I1:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (sbyte)stack.Pop().constant));
break;
case Code.Conv_U1:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (byte)stack.Pop().constant));
break;
case Code.Conv_I2:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (short)stack.Pop().constant));
break;
case Code.Conv_U2:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (ushort)stack.Pop().constant));
break;
case Code.Conv_I4:
case Code.Conv_U4:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, stack.Pop().constant));
break;
case Code.Not:
if (stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, ~stack.Pop().constant));
break;
case Code.Neg:
if (stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, -stack.Pop().constant));
break;
case Code.Ldloc:
case Code.Ldloc_S:
case Code.Ldloc_0:
case Code.Ldloc_1:
case Code.Ldloc_2:
case Code.Ldloc_3:
if (!getLocalConstantInt32(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldarg:
case Code.Ldarg_S:
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
if (!getArgConstantInt32(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldc_I4:
case Code.Ldc_I4_S:
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:
stack.Push(new ConstantInfo(index, DotNetUtils.getLdcI4Value(instr)));
break;
case Code.Add:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant + info2.constant));
break;
case Code.Sub:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant - info2.constant));
break;
case Code.Xor:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant ^ info2.constant));
break;
case Code.Or:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant | info2.constant));
break;
case Code.And:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant & info2.constant));
break;
case Code.Mul:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant * info2.constant));
break;
case Code.Div:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant / info2.constant));
break;
case Code.Div_Un:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, (int)((uint)info1.constant / (uint)info2.constant)));
break;
default:
goto done;
}
}
done:
if (stack.Count == 0)
return false;
while (stack.Count > 1)
stack.Pop();
info1 = stack.Pop();
index = info1.index + 1;
val = info1.constant;
return true;
}
public bool getInt64(ref int index, out long val) {
val = 0;
if (index >= instructions.Count)
return false;
var stack = new Stack>();
long op1;
ConstantInfo info1, info2;
for (; index < instructions.Count; index++) {
if (processInstructionInt64(ref index, stack)) {
index--;
continue;
}
var instr = instructions[index];
switch (instr.OpCode.Code) {
case Code.Conv_I1:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (sbyte)stack.Pop().constant));
break;
case Code.Conv_U1:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (byte)stack.Pop().constant));
break;
case Code.Conv_I2:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (short)stack.Pop().constant));
break;
case Code.Conv_U2:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (ushort)stack.Pop().constant));
break;
case Code.Conv_I4:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (int)stack.Pop().constant));
break;
case Code.Conv_U4:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (uint)stack.Pop().constant));
break;
case Code.Conv_I8:
case Code.Conv_U8:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, stack.Pop().constant));
break;
case Code.Not:
if (stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, ~stack.Pop().constant));
break;
case Code.Neg:
if (stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, -stack.Pop().constant));
break;
case Code.Ldloc:
case Code.Ldloc_S:
case Code.Ldloc_0:
case Code.Ldloc_1:
case Code.Ldloc_2:
case Code.Ldloc_3:
if (!getLocalConstantInt64(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldarg:
case Code.Ldarg_S:
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
if (!getArgConstantInt64(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldc_I8:
stack.Push(new ConstantInfo(index, (long)instr.Operand));
break;
case Code.Add:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant + info2.constant));
break;
case Code.Sub:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant - info2.constant));
break;
case Code.Xor:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant ^ info2.constant));
break;
case Code.Or:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant | info2.constant));
break;
case Code.And:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant & info2.constant));
break;
case Code.Mul:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant * info2.constant));
break;
case Code.Div:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant / info2.constant));
break;
case Code.Div_Un:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, (int)((uint)info1.constant / (uint)info2.constant)));
break;
default:
goto done;
}
}
done:
if (stack.Count == 0)
return false;
while (stack.Count > 1)
stack.Pop();
info1 = stack.Pop();
index = info1.index + 1;
val = info1.constant;
return true;
}
public bool getDouble(ref int index, out double val) {
val = 0;
if (index >= instructions.Count)
return false;
var stack = new Stack>();
double op1;
ConstantInfo info1, info2;
for (; index < instructions.Count; index++) {
if (processInstructionDouble(ref index, stack)) {
index--;
continue;
}
var instr = instructions[index];
switch (instr.OpCode.Code) {
case Code.Conv_R4:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, (float)stack.Pop().constant));
break;
case Code.Conv_R8:
if (!emulateConvInstrs || stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, stack.Pop().constant));
break;
case Code.Neg:
if (stack.Count < 1)
goto done;
stack.Push(new ConstantInfo(index, -stack.Pop().constant));
break;
case Code.Ldloc:
case Code.Ldloc_S:
case Code.Ldloc_0:
case Code.Ldloc_1:
case Code.Ldloc_2:
case Code.Ldloc_3:
if (!getLocalConstantDouble(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldarg:
case Code.Ldarg_S:
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
if (!getArgConstantDouble(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldc_R4:
stack.Push(new ConstantInfo(index, (float)instr.Operand));
break;
case Code.Ldc_R8:
stack.Push(new ConstantInfo(index, (double)instr.Operand));
break;
case Code.Add:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant + info2.constant));
break;
case Code.Sub:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant - info2.constant));
break;
case Code.Mul:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant * info2.constant));
break;
case Code.Div:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, info1.constant / info2.constant));
break;
case Code.Div_Un:
if (stack.Count < 2)
goto done;
info2 = stack.Pop();
info1 = stack.Pop();
stack.Push(new ConstantInfo(index, (int)((uint)info1.constant / (uint)info2.constant)));
break;
default:
goto done;
}
}
done:
if (stack.Count == 0)
return false;
while (stack.Count > 1)
stack.Pop();
info1 = stack.Pop();
index = info1.index + 1;
val = info1.constant;
return true;
}
protected virtual bool getLocalConstantInt32(Instruction instr, out int value) {
value = 0;
if (locals == null)
return false;
var local = DotNetUtils.getLocalVar(locals, instr);
if (local == null)
return false;
if (local.VariableType.EType != ElementType.I4 && local.VariableType.EType != ElementType.U4)
return false;
return localsValuesInt32.TryGetValue(local, out value);
}
protected virtual bool getArgConstantInt32(Instruction instr, out int value) {
value = 0;
return false;
}
protected virtual bool getLocalConstantInt64(Instruction instr, out long value) {
value = 0;
if (locals == null)
return false;
var local = DotNetUtils.getLocalVar(locals, instr);
if (local == null)
return false;
if (local.VariableType.EType != ElementType.I8 && local.VariableType.EType != ElementType.U8)
return false;
return localsValuesInt64.TryGetValue(local, out value);
}
protected virtual bool getArgConstantInt64(Instruction instr, out long value) {
value = 0;
return false;
}
protected virtual bool getLocalConstantDouble(Instruction instr, out double value) {
value = 0;
if (locals == null)
return false;
var local = DotNetUtils.getLocalVar(locals, instr);
if (local == null)
return false;
if (local.VariableType.EType != ElementType.R8)
return false;
return localsValuesDouble.TryGetValue(local, out value);
}
protected virtual bool getArgConstantDouble(Instruction instr, out double value) {
value = 0;
return false;
}
}
}