101 lines
2.8 KiB
C#
101 lines
2.8 KiB
C#
/*
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Copyright (C) 2011-2012 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;
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using System.IO;
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namespace de4dot.code.deobfuscators {
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static class MethodBodyParser {
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public static void parseMethodBody(BinaryReader reader, out byte[] code, out byte[] extraSections) {
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long methodBodyOffset = reader.BaseStream.Position;
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uint codeOffset;
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int codeSize;
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ushort flags;
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switch (peek(reader) & 3) {
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case 2:
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flags = 2;
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codeOffset = 1;
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codeSize = reader.ReadByte() >> 2;
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break;
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case 3:
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flags = reader.ReadUInt16();
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codeOffset = (uint)(4 * (flags >> 12));
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reader.ReadUInt16(); // maxStack
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codeSize = reader.ReadInt32();
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reader.ReadUInt32(); // LocalVarSigTok
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break;
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default:
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throw new ApplicationException("Invalid method body header");
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}
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code = reader.ReadBytes(codeSize);
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if ((flags & 8) != 0)
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extraSections = readExtraSections(reader);
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else
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extraSections = null;
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}
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static void align(BinaryReader reader, int alignment) {
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reader.BaseStream.Position = (reader.BaseStream.Position + alignment - 1) & ~(alignment - 1);
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}
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public static byte[] readExtraSections(BinaryReader reader) {
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align(reader, 4);
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int startPos = (int)reader.BaseStream.Position;
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parseSection(reader);
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int size = (int)reader.BaseStream.Position - startPos;
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reader.BaseStream.Position = startPos;
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return reader.ReadBytes(size);
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}
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static void parseSection(BinaryReader reader) {
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byte flags;
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do {
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align(reader, 4);
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flags = reader.ReadByte();
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if ((flags & 1) == 0)
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throw new ApplicationException("Not an exception section");
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if ((flags & 0x3E) != 0)
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throw new ApplicationException("Invalid bits set");
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if ((flags & 0x40) != 0) {
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reader.BaseStream.Position--;
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int num = (int)(reader.ReadUInt32() >> 8) / 24;
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reader.BaseStream.Position += num * 24;
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}
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else {
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int num = reader.ReadByte() / 12;
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reader.BaseStream.Position += 2 + num * 12;
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}
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} while ((flags & 0x80) != 0);
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}
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static byte peek(BinaryReader reader) {
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byte b = reader.ReadByte();
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reader.BaseStream.Position--;
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return b;
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}
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}
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}
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