mirror of
https://github.com/DosX-dev/Astral-PE
synced 2026-06-06 15:34:31 +00:00
DosX
102 lines
4.7 KiB
C#
102 lines
4.7 KiB
C#
/*
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* This file is part of the Astral-PE project.
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* Copyright (c) 2025 DosX. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* Astral-PE is a low-level post-compilation PE header mutator (obfuscator) for native
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* Windows x86/x64 binaries. It modifies structural metadata while preserving execution integrity.
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*
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* For source code, updates, and documentation, visit:
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* https://github.com/DosX-dev/Astral-PE
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*/
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using PeNet;
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using PeNet.Header.Pe;
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namespace AstralPE.Obfuscator.Modules {
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public class RelocRemover : IAstralPeModule {
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/// <summary>
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/// Removes the relocation directory and section from the PE file if they are not needed.
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/// This operation is skipped for DLL and driver files.
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/// </summary>
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/// <param name="raw">The raw byte array of the PE file.</param>
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/// <param name="pe">The parsed PE file structure.</param>
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/// <param name="e_lfanew">The offset to the IMAGE_NT_HEADERS.</param>
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/// <param name="optStart">The offset to the Optional Header.</param>
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/// <param name="sectionTableOffset">The offset to the section table.</param>
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/// <param name="rnd">Random generator, unused in this module.</param>
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public void Apply(ref byte[] raw, PeFile pe, int e_lfanew, int optStart, int sectionTableOffset, Random rnd) {
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if (pe.IsDll || pe.IsDriver)
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return;
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if (pe.ImageSectionHeaders == null)
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throw new InvalidPeImageException();
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// Locate relocation directory entry in the DataDirectory
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int relocDirOffset = optStart + 0x60 + 5 * 8;
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if (relocDirOffset + 8 > raw.Length)
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throw new ArgumentOutOfRangeException(nameof(relocDirOffset), "Relocation directory offset is outside file bounds.");
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uint relocRva = BitConverter.ToUInt32(raw, relocDirOffset),
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relocSize = BitConverter.ToUInt32(raw, relocDirOffset + 4);
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// Skip if relocation directory is already empty
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if (relocRva == 0 || relocSize == 0)
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return;
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// Find the .reloc section
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ImageSectionHeader? relocSection = pe.ImageSectionHeaders.FirstOrDefault(s =>
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s.Name?.Trim('\0').Equals(".reloc", StringComparison.OrdinalIgnoreCase) == true);
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if (relocSection == null)
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return;
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int offset = (int)relocSection.PointerToRawData,
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size = (int)relocSection.SizeOfRawData;
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if (offset <= 0 || offset + size > raw.Length)
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throw new ArgumentOutOfRangeException(nameof(offset), "Relocation section is outside file bounds.");
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// Ensure that the RVA in the directory entry lies within the .reloc section
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if (relocRva < relocSection.VirtualAddress || relocRva >= relocSection.VirtualAddress + relocSection.VirtualSize)
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return;
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// Clear the raw relocation data and the directory entry
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Array.Clear(raw, offset, size);
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Array.Clear(raw, relocDirOffset, 8);
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// Set IMAGE_FILE_RELOCS_STRIPPED flag in FileHeader.Characteristics
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const ushort IMAGE_FILE_RELOCS_STRIPPED = 0x0001;
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int fileHeaderOffset = e_lfanew + 4, // Skip PE signature
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characteristicsOffset = fileHeaderOffset + 18; // Offset to Characteristics field
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if (characteristicsOffset + 2 <= raw.Length) {
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ushort current = BitConverter.ToUInt16(raw, characteristicsOffset);
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current |= IMAGE_FILE_RELOCS_STRIPPED;
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byte[] updated = BitConverter.GetBytes(current);
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raw[characteristicsOffset] = updated[0];
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raw[characteristicsOffset + 1] = updated[1];
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}
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}
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}
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} |