57 lines
1.8 KiB
C#
57 lines
1.8 KiB
C#
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using dnlib.DotNet;
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using dnlib.DotNet.Emit;
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namespace Obfuscator.Obfuscator.Mutation2;
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public class MulToShift : iMutation
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{
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public void Prepare(TypeDef type)
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{
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}
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public void Process(MethodDef method, ref int index)
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{
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if (!method.Body.Instructions[index - 1].IsLdcI4() || !method.Body.Instructions[index - 2].IsLdcI4())
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{
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return;
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}
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int ldcI4Value = method.Body.Instructions[index - 2].GetLdcI4Value();
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int ldcI4Value2 = method.Body.Instructions[index - 1].GetLdcI4Value();
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if (ldcI4Value2 < 3)
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{
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return;
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}
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Local local = new Local(method.Module.CorLibTypes.Int32);
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method.Body.Variables.Add(local);
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method.Body.Instructions.Insert(0, new Instruction(OpCodes.Stloc, local));
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method.Body.Instructions.Insert(0, new Instruction(OpCodes.Ldc_I4, ldcI4Value));
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index += 2;
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method.Body.Instructions[index - 2].OpCode = OpCodes.Ldloc;
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method.Body.Instructions[index - 2].Operand = local;
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method.Body.Instructions[index - 1].OpCode = OpCodes.Nop;
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method.Body.Instructions[index].OpCode = OpCodes.Nop;
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int num = 0;
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for (int num2 = ldcI4Value2; num2 > 0; num2 >>= 1)
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{
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if ((num2 & 1) == 1 && num != 0)
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{
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method.Body.Instructions.Insert(++index, new Instruction(OpCodes.Ldloc, local));
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method.Body.Instructions.Insert(++index, new Instruction(OpCodes.Ldc_I4, num));
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method.Body.Instructions.Insert(++index, new Instruction(OpCodes.Shl));
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method.Body.Instructions.Insert(++index, new Instruction(OpCodes.Add));
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}
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num++;
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}
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if ((ldcI4Value2 & 1) == 0)
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{
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method.Body.Instructions.Insert(++index, new Instruction(OpCodes.Ldloc, local));
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method.Body.Instructions.Insert(++index, new Instruction(OpCodes.Sub));
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}
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}
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public bool Supported(Instruction instr)
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{
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return instr.OpCode == OpCodes.Mul;
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}
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}
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