71 lines
2.0 KiB
C#
71 lines
2.0 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;
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using dnlib.DotNet.Emit;
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namespace de4dot.blocks.cflow {
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// Replace stloc + ldloc with dup + stloc
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class StLdlocFixer : BlockDeobfuscator {
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IList<Local> locals;
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protected override void Initialize(List<Block> allBlocks) {
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base.Initialize(allBlocks);
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locals = blocks.Locals;
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}
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protected override bool Deobfuscate(Block block) {
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bool modified = false;
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var instructions = block.Instructions;
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for (int i = 0; i < instructions.Count; i++) {
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var instr = instructions[i];
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switch (instr.OpCode.Code) {
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// Xenocode generates stloc + ldloc (bool). Replace it with dup + stloc. It will eventually
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// become dup + pop and be removed.
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case Code.Stloc:
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case Code.Stloc_S:
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case Code.Stloc_0:
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case Code.Stloc_1:
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case Code.Stloc_2:
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case Code.Stloc_3:
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if (i + 1 >= instructions.Count)
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break;
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if (!instructions[i + 1].IsLdloc())
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break;
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var local = Instr.GetLocalVar(locals, instr);
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if (local.Type.ElementType != ElementType.Boolean)
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continue;
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if (local != Instr.GetLocalVar(locals, instructions[i + 1]))
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break;
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instructions[i] = new Instr(OpCodes.Dup.ToInstruction());
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instructions[i + 1] = instr;
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modified = true;
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break;
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default:
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break;
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}
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}
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return modified;
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}
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}
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}
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