120 lines
4.6 KiB
C#
120 lines
4.6 KiB
C#
/*
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Copyright (C) 2011-2015 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System.Collections.Generic;
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using dnlib.DotNet.Emit;
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using de4dot.blocks;
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using de4dot.blocks.cflow;
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namespace de4dot.code.deobfuscators.Confuser {
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class ConstantsFolder : BlockDeobfuscator {
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protected override bool Deobfuscate(Block block) {
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bool modified = false;
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var instrs = block.Instructions;
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var constantsReader = CreateConstantsReader(instrs);
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for (int i = 0; i < instrs.Count; i++) {
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int index = 0;
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Instruction newInstr = null;
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var instr = instrs[i];
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if (constantsReader.IsLoadConstantInt32(instr.Instruction)) {
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index = i;
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int val;
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if (!constantsReader.GetInt32(ref index, out val))
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continue;
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newInstr = Instruction.CreateLdcI4(val);
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}
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else if (constantsReader.IsLoadConstantInt64(instr.Instruction)) {
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index = i;
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long val;
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if (!constantsReader.GetInt64(ref index, out val))
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continue;
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newInstr = Instruction.Create(OpCodes.Ldc_I8, val);
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}
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else if (constantsReader.IsLoadConstantDouble(instr.Instruction)) {
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index = i;
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double val;
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if (!constantsReader.GetDouble(ref index, out val))
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continue;
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newInstr = Instruction.Create(OpCodes.Ldc_R8, val);
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}
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if (newInstr != null && index - i > 1) {
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block.Insert(index++, Instruction.Create(OpCodes.Pop));
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block.Insert(index++, newInstr);
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i = index - 1;
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constantsReader = CreateConstantsReader(instrs);
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modified = true;
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continue;
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}
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// Convert ldc.r4/r8 followed by conv to the appropriate ldc.i4/i8 instr
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if (i + 1 < instrs.Count && (instr.OpCode.Code == Code.Ldc_R4 || instr.OpCode.Code == Code.Ldc_R8)) {
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var conv = instrs[i + 1];
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/*int vali32 = instr.OpCode.Code == Code.Ldc_R4 ? (int)(float)instr.Operand : (int)(double)instr.Operand;
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long vali64 = instr.OpCode.Code == Code.Ldc_R4 ? (long)(float)instr.Operand : (long)(double)instr.Operand;
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uint valu32 = instr.OpCode.Code == Code.Ldc_R4 ? (uint)(float)instr.Operand : (uint)(double)instr.Operand;
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ulong valu64 = instr.OpCode.Code == Code.Ldc_R4 ? (ulong)(float)instr.Operand : (ulong)(double)instr.Operand;*/
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switch (conv.OpCode.Code) {
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case Code.Conv_I1:
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newInstr = Instruction.CreateLdcI4(instr.OpCode.Code == Code.Ldc_R4 ? (sbyte)(float)instr.Operand : (sbyte)(double)instr.Operand);
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break;
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case Code.Conv_U1:
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newInstr = Instruction.CreateLdcI4(instr.OpCode.Code == Code.Ldc_R4 ? (byte)(float)instr.Operand : (byte)(double)instr.Operand);
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break;
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case Code.Conv_I2:
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newInstr = Instruction.CreateLdcI4(instr.OpCode.Code == Code.Ldc_R4 ? (short)(float)instr.Operand : (short)(double)instr.Operand);
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break;
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case Code.Conv_U2:
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newInstr = Instruction.CreateLdcI4(instr.OpCode.Code == Code.Ldc_R4 ? (ushort)(float)instr.Operand : (ushort)(double)instr.Operand);
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break;
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case Code.Conv_I4:
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newInstr = Instruction.CreateLdcI4(instr.OpCode.Code == Code.Ldc_R4 ? (int)(float)instr.Operand : (int)(double)instr.Operand);
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break;
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case Code.Conv_U4:
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newInstr = Instruction.CreateLdcI4(instr.OpCode.Code == Code.Ldc_R4 ? (int)(uint)(float)instr.Operand : (int)(uint)(double)instr.Operand);
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break;
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case Code.Conv_I8:
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newInstr = Instruction.Create(OpCodes.Ldc_I8, instr.OpCode.Code == Code.Ldc_R4 ? (long)(float)instr.Operand : (long)(double)instr.Operand);
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break;
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case Code.Conv_U8:
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newInstr = Instruction.Create(OpCodes.Ldc_I8, instr.OpCode.Code == Code.Ldc_R4 ? (ulong)(float)instr.Operand : (ulong)(double)instr.Operand);
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break;
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default:
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newInstr = null;
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break;
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}
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if (newInstr != null) {
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block.Replace(i, 2, newInstr);
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constantsReader = CreateConstantsReader(instrs);
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modified = true;
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continue;
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}
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}
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}
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return modified;
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}
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static ConstantsReader CreateConstantsReader(IList<Instr> instrs) {
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return new ConstantsReader(instrs, false);
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}
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}
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}
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