Esempio n. 1
0
        // Switch deobfuscation when block uses ldloc N to load switch constant
        //	blk1:
        //		ldc.i4 X
        //		stloc N
        //		br swblk / bcc swblk
        //	swblk:
        //		ldloc N
        //		switch (......)
        bool DeobfuscateLdloc(IList <Block> switchTargets, Block switchFallThrough, Block block, Local switchVariable)
        {
            bool modified = false;

            foreach (var source in new List <Block>(block.Sources))
            {
                if (isBranchBlock(source))
                {
                    instructionEmulator.Initialize(blocks, allBlocks[0] == source);
                    instructionEmulator.Emulate(source.Instructions);

                    var target = GetSwitchTarget(switchTargets, switchFallThrough, instructionEmulator.GetLocal(switchVariable));
                    if (target == null)
                    {
                        continue;
                    }
                    source.ReplaceLastNonBranchWithBranch(0, target);
                    modified = true;
                }
                else if (IsBccBlock(source))
                {
                    instructionEmulator.Initialize(blocks, allBlocks[0] == source);
                    instructionEmulator.Emulate(source.Instructions);

                    var target = GetSwitchTarget(switchTargets, switchFallThrough, instructionEmulator.GetLocal(switchVariable));
                    if (target == null)
                    {
                        continue;
                    }
                    if (source.Targets[0] == block)
                    {
                        source.SetNewTarget(0, target);
                        modified = true;
                    }
                    if (source.FallThrough == block)
                    {
                        source.SetNewFallThrough(target);
                        modified = true;
                    }
                }
            }
            return(modified);
        }
        protected override bool Deobfuscate(Block block)
        {
            bool modified = false;

            instructionEmulator.Initialize(blocks, allBlocks[0] == block);
            var instrs = block.Instructions;

            for (int i = 0; i < instrs.Count; i++)
            {
                var instr = instrs[i];

                switch (instr.OpCode.Code)
                {
                case Code.Ldarg:
                case Code.Ldarg_0:
                case Code.Ldarg_1:
                case Code.Ldarg_2:
                case Code.Ldarg_3:
                case Code.Ldarg_S:
                    modified |= FixLoadInstruction(block, i, instructionEmulator.GetArg(instr.Instruction.GetParameter(args)));
                    break;

                case Code.Ldloc:
                case Code.Ldloc_0:
                case Code.Ldloc_1:
                case Code.Ldloc_2:
                case Code.Ldloc_3:
                case Code.Ldloc_S:
                    modified |= FixLoadInstruction(block, i, instructionEmulator.GetLocal(instr.Instruction.GetLocal(blocks.Locals)));
                    break;

                case Code.Ldarga:
                case Code.Ldarga_S:
                    instructionEmulator.MakeArgUnknown((Parameter)instr.Operand);
                    break;

                case Code.Ldloca:
                case Code.Ldloca_S:
                    instructionEmulator.MakeLocalUnknown((Local)instr.Operand);
                    break;
                }

                try {
                    instructionEmulator.Emulate(instr.Instruction);
                }
                catch (NullReferenceException) {
                    // Here if eg. invalid metadata token in a call instruction (operand is null)
                    break;
                }
            }

            return(modified);
        }
Esempio n. 3
0
        protected override bool Deobfuscate(Block block)
        {
            bool modified = false;

            instructionEmulator.Initialize(Blocks, AllBlocks[0] == block);
            var instrs = block.Instructions;

            for (int i = 0; i < instrs.Count; i++)
            {
                var instr = instrs[i];

                switch (instr.OpCode.Code)
                {
                case Code.Ldarg:
                case Code.Ldarg_0:
                case Code.Ldarg_1:
                case Code.Ldarg_2:
                case Code.Ldarg_3:
                case Code.Ldarg_S:
                    modified |= FixLoadInstruction(block, i, instructionEmulator.GetArg(instr.Instruction.GetParameter(args)));
                    break;

                case Code.Ldloc:
                case Code.Ldloc_0:
                case Code.Ldloc_1:
                case Code.Ldloc_2:
                case Code.Ldloc_3:
                case Code.Ldloc_S:
                    modified |= FixLoadInstruction(block, i, instructionEmulator.GetLocal(instr.Instruction.GetLocal(Blocks.Locals)));
                    break;

                case Code.Ldarga:
                case Code.Ldarga_S:
                    instructionEmulator.MakeArgUnknown((Parameter)instr.Operand);
                    break;

                case Code.Ldloca:
                case Code.Ldloca_S:
                    instructionEmulator.MakeLocalUnknown((Local)instr.Operand);
                    break;

                case Code.Add:
                case Code.Add_Ovf:
                case Code.Add_Ovf_Un:
                case Code.And:
                case Code.Ceq:
                case Code.Cgt:
                case Code.Cgt_Un:
                case Code.Clt:
                case Code.Clt_Un:
                case Code.Conv_I:
                case Code.Conv_I1:
                case Code.Conv_I2:
                case Code.Conv_I4:
                case Code.Conv_I8:
                case Code.Conv_Ovf_I:
                case Code.Conv_Ovf_I_Un:
                case Code.Conv_Ovf_I1:
                case Code.Conv_Ovf_I1_Un:
                case Code.Conv_Ovf_I2:
                case Code.Conv_Ovf_I2_Un:
                case Code.Conv_Ovf_I4:
                case Code.Conv_Ovf_I4_Un:
                case Code.Conv_Ovf_I8:
                case Code.Conv_Ovf_I8_Un:
                case Code.Conv_Ovf_U:
                case Code.Conv_Ovf_U_Un:
                case Code.Conv_Ovf_U1:
                case Code.Conv_Ovf_U1_Un:
                case Code.Conv_Ovf_U2:
                case Code.Conv_Ovf_U2_Un:
                case Code.Conv_Ovf_U4:
                case Code.Conv_Ovf_U4_Un:
                case Code.Conv_Ovf_U8:
                case Code.Conv_Ovf_U8_Un:
                case Code.Conv_R_Un:
                case Code.Conv_R4:
                case Code.Conv_R8:
                case Code.Conv_U:
                case Code.Conv_U1:
                case Code.Conv_U2:
                case Code.Conv_U4:
                case Code.Conv_U8:
                case Code.Div:
                case Code.Div_Un:
                case Code.Dup:
                case Code.Mul:
                case Code.Mul_Ovf:
                case Code.Mul_Ovf_Un:
                case Code.Neg:
                case Code.Not:
                case Code.Or:
                case Code.Rem:
                case Code.Rem_Un:
                case Code.Shl:
                case Code.Shr:
                case Code.Shr_Un:
                case Code.Sub:
                case Code.Sub_Ovf:
                case Code.Sub_Ovf_Un:
                case Code.Xor:
                    if (DisableNewCode)
                    {
                        break;
                    }
                    if (i + 1 < instrs.Count && instrs[i + 1].OpCode.Code == Code.Pop)
                    {
                        break;
                    }
                    if (!VerifyValidArgs(instr.Instruction))
                    {
                        break;
                    }
                    instructionEmulator.Emulate(instr.Instruction);
                    var         tos      = instructionEmulator.Peek();
                    Instruction newInstr = null;
                    if (tos.IsInt32())
                    {
                        var val = (Int32Value)tos;
                        if (val.AllBitsValid())
                        {
                            newInstr = Instruction.CreateLdcI4(val.Value);
                        }
                    }
                    else if (tos.IsInt64())
                    {
                        var val = (Int64Value)tos;
                        if (val.AllBitsValid())
                        {
                            newInstr = OpCodes.Ldc_I8.ToInstruction(val.Value);
                        }
                    }
                    else if (tos.IsReal8())
                    {
                        var val = (Real8Value)tos;
                        if (val.IsValid)
                        {
                            newInstr = GetLoadRealInstruction(val.Value);
                        }
                    }
                    if (newInstr != null)
                    {
                        block.Insert(i + 1, Instruction.Create(OpCodes.Pop));
                        block.Insert(i + 2, newInstr);
                        i       += 2;
                        modified = true;
                    }
                    continue;
                }

                try {
                    instructionEmulator.Emulate(instr.Instruction);
                }
                catch (NullReferenceException) {
                    // Here if eg. invalid metadata token in a call instruction (operand is null)
                    break;
                }
            }

            return(modified);
        }
Esempio n. 4
0
		// 5.1+
		// the only changes are the indexes of ldloc and stfld
		bool EmulateDynocodeNew(InstructionEmulator emu, ref int index) {
			var instrs = stringMethod.Body.Instructions;
			var instr = instrs[index];

			var ctor = instr.Operand as MethodDef;
			if (ctor == null || ctor.MethodSig.GetParamCount() != 1 || ctor.MethodSig.Params[0].ElementType != ElementType.I4)
				return false;

			if (index + 4 >= instrs.Count)
				return false;
			var ldloc = instrs[index + 2];
			var stfld = instrs[index + 3];
			if (!ldloc.IsLdloc() || stfld.OpCode.Code != Code.Stfld)
				return false;
			var enumerableField = stfld.Operand as FieldDef;
			if (enumerableField == null)
				return false;

			var initValue = emu.GetLocal(ldloc.GetLocal(stringMethod.Body.Variables)) as Int32Value;
			if (initValue == null || !initValue.AllBitsValid())
				return false;

			int leaveIndex = FindLeave(instrs, index);
			if (leaveIndex < 0)
				return false;
			var afterLoop = instrs[leaveIndex].Operand as Instruction;
			if (afterLoop == null)
				return false;
			int newIndex = instrs.IndexOf(afterLoop);
			var loopLocal = GetDCLoopLocal(index, newIndex);
			if (loopLocal == null)
				return false;
			var initValue2 = emu.GetLocal(loopLocal) as Int32Value;
			if (initValue2 == null || !initValue2.AllBitsValid())
				return false;

			int loopStart = GetIndexOfCall(instrs, index, leaveIndex, "System.Int32", "()");
			int loopEnd = GetIndexOfCall(instrs, loopStart, leaveIndex, "System.Boolean", "()");
			if (loopStart < 0 || loopEnd < 0)
				return false;
			loopStart++;
			loopEnd--;

			dynocode.Initialize(module);
			var ctorArg = emu.Pop() as Int32Value;
			if (ctorArg == null || !ctorArg.AllBitsValid())
				return false;
			dynocode.CreateEnumerable(ctor, new object[] { ctorArg.Value });
			dynocode.WriteEnumerableField(enumerableField.MDToken.ToUInt32(), initValue.Value);
			dynocode.CreateEnumerator();
			foreach (var val in dynocode) {
				emu.Push(new Int32Value(val));
				for (int i = loopStart; i < loopEnd; i++)
					emu.Emulate(instrs[i]);
			}

			index = newIndex - 1;
			return true;
		}