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Make sure index is correct, and add method to read arg constants

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This commit is contained in:
de4dot 2012-05-02 10:47:21 +02:00
parent 6f807f2484
commit db14e73369
1 changed files with 103 additions and 25 deletions
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128
de4dot.code/deobfuscators/ConstantsReader.cs
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@ -66,16 +66,24 @@ namespace de4dot.code.deobfuscators {
}
}
public ConstantsReader(MethodDefinition method) {
this.locals = method.Body.Variables;
this.instructions = new ListInstructions(method.Body.Instructions);
public ConstantsReader(IList<Instruction> instrs) {
this.instructions = new ListInstructions(instrs);
}
public ConstantsReader(IList<VariableDefinition> locals, IList<Instr> instrs) {
this.locals = locals;
public ConstantsReader(IList<Instr> instrs) {
this.instructions = new ListInstrs(instrs);
}
public ConstantsReader(MethodDefinition method)
: this(method.Body.Instructions) {
this.locals = method.Body.Variables;
}
public ConstantsReader(IList<Instr> instrs, IList<VariableDefinition> locals)
: this(instrs) {
this.locals = locals;
}
public bool getNextInt32(ref int index, out int val) {
for (; index < instructions.Count; index++) {
var instr = instructions[index];
@ -92,10 +100,15 @@ namespace de4dot.code.deobfuscators {
public bool isLoadConstant(Instruction instr) {
if (DotNetUtils.isLdcI4(instr))
return true;
if (!DotNetUtils.isLdloc(instr))
return false;
int tmp;
return getLocalConstant(instr, out tmp);
if (DotNetUtils.isLdloc(instr)) {
int tmp;
return getLocalConstant(instr, out tmp);
}
if (DotNetUtils.isLdarg(instr)) {
int tmp;
return getArgConstant(instr, out tmp);
}
return false;
}
public bool getInt16(ref int index, out short val) {
@ -109,51 +122,62 @@ namespace de4dot.code.deobfuscators {
return true;
}
struct ConstantInfo {
public int index;
public int constant;
public ConstantInfo(int index, int constant) {
this.index = index;
this.constant = constant;
}
}
public bool getInt32(ref int index, out int val) {
val = 0;
if (index >= instructions.Count)
return false;
var stack = new Stack<int>();
var stack = new Stack<ConstantInfo>();
int op1;
ConstantInfo info1, info2;
for (; index < instructions.Count; index++) {
var instr = instructions[index];
switch (instr.OpCode.Code) {
case Code.Conv_I1:
if (stack.Count < 1)
goto done;
stack.Push((sbyte)stack.Pop());
stack.Push(new ConstantInfo(index, (sbyte)stack.Pop().constant));
break;
case Code.Conv_U1:
if (stack.Count < 1)
goto done;
stack.Push((byte)stack.Pop());
stack.Push(new ConstantInfo(index, (byte)stack.Pop().constant));
break;
case Code.Conv_I2:
if (stack.Count < 1)
goto done;
stack.Push((short)stack.Pop());
stack.Push(new ConstantInfo(index, (short)stack.Pop().constant));
break;
case Code.Conv_U2:
if (stack.Count < 1)
goto done;
stack.Push((ushort)stack.Pop());
stack.Push(new ConstantInfo(index, (ushort)stack.Pop().constant));
break;
case Code.Conv_I4:
case Code.Conv_U4:
stack.Push(new ConstantInfo(index, stack.Pop().constant));
break;
case Code.Not:
stack.Push(~stack.Pop());
stack.Push(new ConstantInfo(index, ~stack.Pop().constant));
break;
case Code.Neg:
stack.Push(-stack.Pop());
stack.Push(new ConstantInfo(index, -stack.Pop().constant));
break;
case Code.Ldloc:
@ -164,7 +188,18 @@ namespace de4dot.code.deobfuscators {
case Code.Ldloc_3:
if (!getLocalConstant(instr, out op1))
goto done;
stack.Push(op1);
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 (!getArgConstant(instr, out op1))
goto done;
stack.Push(new ConstantInfo(index, op1));
break;
case Code.Ldc_I4:
@ -179,37 +214,71 @@ namespace de4dot.code.deobfuscators {
case Code.Ldc_I4_7:
case Code.Ldc_I4_8:
case Code.Ldc_I4_M1:
stack.Push(DotNetUtils.getLdcI4Value(instr));
stack.Push(new ConstantInfo(index, DotNetUtils.getLdcI4Value(instr)));
break;
case Code.Add:
if (stack.Count < 2)
goto done;
stack.Push(stack.Pop() + stack.Pop());
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;
stack.Push(-(stack.Pop() - stack.Pop()));
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;
stack.Push(stack.Pop() ^ stack.Pop());
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;
stack.Push(stack.Pop() | stack.Pop());
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;
stack.Push(stack.Pop() & stack.Pop());
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:
@ -221,12 +290,16 @@ done:
return false;
while (stack.Count > 1)
stack.Pop();
val = stack.Pop();
info1 = stack.Pop();
index = info1.index + 1;
val = info1.constant;
return true;
}
bool getLocalConstant(Instruction instr, out int value) {
protected virtual bool getLocalConstant(Instruction instr, out int value) {
value = 0;
if (locals == null)
return false;
var local = DotNetUtils.getLocalVar(locals, instr);
if (local == null)
return false;
@ -234,5 +307,10 @@ done:
return false;
return localsValues.TryGetValue(local, out value);
}
protected virtual bool getArgConstant(Instruction instr, out int value) {
value = 0;
return false;
}
}
}