Hallo Evain,
thanks for writing Cecil its a really great project.
Here is my method to to replace all ldstr with my encryption method
private void InjectCode(MethodBody body, CryptingMethodType
eCryptingMethod, MethodReference refDecryptionMethod)
{
InstructionCollection instructions =
(InstructionCollection)body.Instructions;
ILProcessor ilProcessor = body.GetILProcessor( );
List<int> listOffsets = new List<int>( );
int instructionSize = 0;
//Search for all ldstr Instructions
List<Instruction> listInstructionsToChange = new
List<Instruction>( );
foreach (Instruction instruction in instructions)
{
if (instruction.OpCode.Name == "ldstr")
{
if (instruction.Operand is string)
listInstructionsToChange.Add(instruction);
}
}
// Insert my Encryption Methode
if (instructions.Count > 0)
body.SimplifyMacros( );
foreach (Instruction instruction in
listInstructionsToChange)
{
listOffsets.Add(instruction.Offset);
string sOriginalValue =
instruction.Operand.ToString( );
KeyValuePair<string, object> pairStringAndKey =
GetEncryptedStringAndKey(sOriginalValue, eCryptingMethod);
string value = pairStringAndKey.Key;
object key = pairStringAndKey.Value;
Instruction loadKey = null;
if (key is int)
loadKey = ilProcessor.Create(OpCodes.Ldc_I4,
(int)key);
if (key is string)
loadKey = ilProcessor.Create(OpCodes.Ldstr,
(string)key);
Instruction loadString =
ilProcessor.Create(OpCodes.Ldstr, value);
ilProcessor.Replace(instruction, loadString);
ilProcessor.InsertAfter(loadString, loadKey);
Instruction callMethod =
ilProcessor.Create(OpCodes.Call, refDecryptionMethod);
ilProcessor.InsertAfter(loadKey, callMethod);
instructionSize = loadKey.GetSize( ) +
loadString.GetSize( );
}
if (instructions.Count > 0)
body.OptimizeMacros( );
}
Now i use it on a simple Programm.
////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
I dont use the { } symbols in the "else" and "default:" statements.
Without them the programm will crash.
static void Main(string[] args)
{
if (someString == "Text")
Console.WriteLine("Some string is Text");
else //I dont use the symbols { }
Console.WriteLine("Some string is somehing else");
//Crash becouse of wrong offsets
switch (someString)
{
case "Text":
Console.WriteLine("Some string is Text");
break;
case "None":
Console.WriteLine("Some string is None");
break;
default: //I dont use the symbols { }
Console.WriteLine("Some string is something
else");
break;
//Crash becouse the wrong offsets
}
}
IL CODE //Look at brtrue.s L_0024
.method private hidebysig static void Main(string[] args) cil managed
{
.maxstack 3
.locals init (
[0] bool flag,
[1] string str)
L_0000: nop
L_0001: ldsfld string
Log4Me.Logic.Cloaking.Cloaking_StringsEncryption::someString
L_0006: ldstr "\ubcf1\ubcc0\ubcdd\ubcd1"
L_000b: ldc.i4 0x7098bca5
L_0010: call string <Module>::StringDecryption(string, int32)
L_0015: call bool [mscorlib]System.String::op_Equality(string,
string)
L_001a: ldc.i4.0
L_001b: ceq
L_001d: stloc.0
L_001e: ldloc.0
L_001f: brtrue.s L_0024 <<<<<<<<<<<shows on
nothing ?????????????????????????
L_0021: ldstr "\u123b\u1207\u1205\u120d\u1248\u121b\u121c\u121a
\u1201\u1206\u120f\u1248\u1201\u121b\u1248\u123c\u120d\u1210\u121c"
L_0026: ldc.i4 0x58561268
L_002b: call string <Module>::StringDecryption(string, int32)
L_0030: call void [mscorlib]System.Console::WriteLine(string)
L_0035: nop
L_0036: br.s L_004d
L_0038: ldstr "\u162e\u1612\u1610\u1618\u165d\u160e\u1609\u160f
\u1614\u1613\u161a\u165d\u1614\u160e\u165d\u160e
\u1612\u1610\u1618\u1615\u1614\u1613\u161a\u165d\u1618\u1611\u160e
\u1618"
L_003d: ldc.i4 0x4292167d
L_0042: call string <Module>::StringDecryption(string, int32)
L_0047: call void [mscorlib]System.Console::WriteLine(string)
L_004c: nop
L_004d: ldsfld string MyProgramm.Form::someString
L_0052: stloc.1
L_0053: ldloc.1
L_0054: brfalse.s L_006e
L_0056: ldloc.1
L_0057: ldstr "\u3d46\u3d77\u3d6a\u3d66"
L_005c: ldc.i4 0x28083d12
L_0061: call string <Module>::StringDecryption(string, int32)
L_0066: call bool [mscorlib]System.String::op_Equality(string,
string)
L_006b: brtrue.s L_0054
L_006d: ldloc.1
L_006e: ldstr "\u6f68\u6f49\u6f48\u6f43"
L_0073: ldc.i4 0x2ab66f26
L_0078: call string <Module>::StringDecryption(string, int32)
L_007d: call bool [mscorlib]System.String::op_Equality(string,
string)
L_0082: brtrue.s L_0061
L_0084: br.s L_006e
L_0086: ldstr "\u010a\u0136\u0134\u013c\u0179\u012a\u012d\u012b
\u0130\u0137\u013e\u0179\u0130\u012a\u0179\u010d\u013c\u0121\u012d"
L_008b: ldc.i4 0x6cef0159
L_0090: call string <Module>::StringDecryption(string, int32)
L_0095: call void [mscorlib]System.Console::WriteLine(string)
L_009a: nop
L_009b: br.s L_00cb
L_009d: ldstr "\u51d3\u51ef\u51ed
\u51e5\u51a0\u51f3\u51f4\u51f2\u51e9\u51ee
\u51e7\u51a0\u51e9\u51f3\u51a0\u51ce\u51ef\u51ee\u51e5"
L_00a2: ldc.i4 0x6d315180
L_00a7: call string <Module>::StringDecryption(string, int32)
L_00ac: call void [mscorlib]System.Console::WriteLine(string)
L_00b1: nop
L_00b2: br.s L_00cb
L_00b4: ldstr "\u6d9b\u6da7\u6da5\u6dad\u6de8\u6dbb\u6dbc\u6dba
\u6da1\u6da6\u6daf\u6de8\u6da1\u6dbb\u6de8\u6dbb\u6da7\u6da5\u6dad
\u6dbc\u6da0\u6da1\u6da6\u6daf\u6de8\u6dad\u6da4\u6dbb\u6dad"
L_00b9: ldc.i4 0x8b6dc8
L_00be: call string <Module>::StringDecryption(string, int32)
L_00c3: call void [mscorlib]System.Console::WriteLine(string)
L_00c8: nop
L_00c9: br.s L_00cb
L_00cb: ret
}
////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
I used the { } symbols in the "else" and "default:" statements.
The programm works well.
static void Main(string[] args)
{
if (someString == "Text")
Console.WriteLine("Some string is Text");
else //I use the symbols { }
{
Console.WriteLine("Some string is somehing else");
//works fine
}
switch (someString)
{
case "Text":
Console.WriteLine("Some string is Text");
break;
case "None":
Console.WriteLine("Some string is None");
break;
default: //I use the symbols { }
{
Console.WriteLine("Some string is something
else");
break;
//works fine
}
}
}
IL CODE
.method private hidebysig static void Main(string[] args) cil managed
{
.maxstack 3
.locals init (
[0] bool flag,
[1] string str)
L_0000: nop
L_0001: ldsfld string MyProgram.Form1::someString
L_0006: ldstr "\u9220\u9211\u920c\u9200"
L_000b: ldc.i4 0x74099274
L_0010: call string <Module>::StringDecryption(string, int32)
L_0015: call bool [mscorlib]System.String::op_Equality(string,
string)
L_001a: ldc.i4.0
L_001b: ceq
L_001d: stloc.0
L_001e: ldloc.0
L_001f: brtrue.s L_0038
L_0021: ldstr "\ufb35\ufb09\ufb0b
\ufb03\ufb46\ufb15\ufb12\ufb14\ufb0f\ufb08\ufb01\ufb46\ufb0f
\ufb15\ufb46\ufb32\ufb03\ufb1e\ufb12"
L_0026: ldc.i4 0x1452fb66
L_002b: call string <Module>::StringDecryption(string, int32)
L_0030: call void [mscorlib]System.Console::WriteLine(string)
L_0035: nop
L_0036: br.s L_004f
L_0038: nop
L_0039: ldstr "\u0bd5\u0be9\u0beb
\u0be3\u0ba6\u0bf5\u0bf2\u0bf4\u0bef\u0be8\u0be1\u0ba6\u0bef
\u0bf5\u0ba6\u0bf5\u0be9\u0beb\u0be3\u0bee\u0bef
\u0be8\u0be1\u0ba6\u0be3\u0bea\u0bf5\u0be3"
L_003e: ldc.i4 0x5aa0b86
L_0043: call string <Module>::StringDecryption(string, int32)
L_0048: call void [mscorlib]System.Console::WriteLine(string)
L_004d: nop
L_004e: nop
L_004f: ldsfld string
Log4Me.Logic.Cloaking.Cloaking_StringsEncryption::someString
L_0054: stloc.1
L_0055: ldloc.1
L_0056: brfalse.s L_00b6
L_0058: ldloc.1
L_0059: ldstr "\u81d9\u81e8\u81f5\u81f9"
L_005e: ldc.i4 0x7f9a818d
L_0063: call string <Module>::StringDecryption(string, int32)
L_0068: call bool [mscorlib]System.String::op_Equality(string,
string)
L_006d: brtrue.s L_0056
L_006f: ldloc.1
L_0070: ldstr "\u98ca\u98eb\u98ea\u98e1"
L_0075: ldc.i4 0x496d9884
L_007a: call string <Module>::StringDecryption(string, int32)
L_007f: call bool [mscorlib]System.String::op_Equality(string,
string)
L_0084: brtrue.s L_0063
L_0086: br.s L_00b6
L_0088: ldstr "\u9d46\u9d7a
\u9d78\u9d70\u9d35\u9d66\u9d61\u9d67\u9d7c\u9d7b\u9d72\u9d35\u9d7c
\u9d66\u9d35\u9d41\u9d70\u9d6d\u9d61"
L_008d: ldc.i4 0x2b349d15
L_0092: call string <Module>::StringDecryption(string, int32)
L_0097: call void [mscorlib]System.Console::WriteLine(string)
L_009c: nop
L_009d: br.s L_00ce
L_009f: ldstr "\u0373\u034f\u034d
\u0345\u0300\u0353\u0354\u0352\u0349\u034e
\u0347\u0300\u0349\u0353\u0300\u036e\u034f\u034e\u0345"
L_00a4: ldc.i4 0x6ae50320
L_00a9: call string <Module>::StringDecryption(string, int32)
L_00ae: call void [mscorlib]System.Console::WriteLine(string)
L_00b3: nop
L_00b4: br.s L_00ce
L_00b6: nop
L_00b7: ldstr "\ubd1b\ubd27\ubd25\ubd2d\ubd68\ubd3b\ubd3c\ubd3a
\ubd21\ubd26\ubd2f\ubd68\ubd21\ubd3b\ubd68\ubd3b\ubd27\ubd25\ubd2d
\ubd3c\ubd20\ubd21\ubd26\ubd2f\ubd68\ubd2d\ubd24\ubd3b\ubd2d"
L_00bc: ldc.i4 0x4d4dbd48
L_00c1: call string <Module>::StringDecryption(string, int32)
L_00c6: call void [mscorlib]System.Console::WriteLine(string)
L_00cb: nop
L_00cc: br.s L_00ce
L_00ce: ret
}
--
--
mono-cecil
