113 lines
4.2 KiB
C#
113 lines
4.2 KiB
C#
/*
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Copyright 2017-2019 Katy Coe - http://www.djkaty.com - https://github.com/djkaty
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All rights reserved.
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*/
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using System;
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using System.Linq;
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namespace Il2CppInspector
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{
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internal class Il2CppBinaryX86 : Il2CppBinary
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{
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public Il2CppBinaryX86(IFileFormatStream stream, EventHandler<string> statusCallback = null) : base(stream, statusCallback) { }
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public Il2CppBinaryX86(IFileFormatStream stream, uint codeRegistration, uint metadataRegistration, EventHandler<string> statusCallback = null)
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: base(stream, codeRegistration, metadataRegistration, statusCallback) { }
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protected override (ulong, ulong) ConsiderCode(IFileFormatStream image, uint loc) {
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ulong metadata, code;
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long pCgr;
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// x86
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// Assembly bytes to search for at start of each function
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var bytes = new byte[] {0x6A, 0x00, 0x6A, 0x00, 0x68};
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image.Position = loc;
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var buff = image.ReadBytes(5);
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if (bytes.SequenceEqual(buff)) {
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// Next 4 bytes are the function pointer being pushed onto the stack
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pCgr = image.ReadUInt32();
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// Start of next instruction
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if (image.ReadByte() != 0xB9)
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return (0, 0);
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// Jump to Il2CppCodegenRegistration
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if(image.Version < 21) {
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image.Position = image.MapVATR((ulong)pCgr + 1);
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metadata = image.ReadUInt32();
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image.Position = image.MapVATR((ulong)pCgr + 6);
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code = image.ReadUInt32();
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} else {
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image.Position = image.MapVATR((ulong)pCgr + 6);
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metadata = image.ReadUInt32();
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image.Position = image.MapVATR((ulong)pCgr + 11);
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code = image.ReadUInt32();
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}
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return (code, metadata);
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}
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// x86 based on ELF PLT
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if (image is IElfReader elf) {
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var plt = elf.GetPLTAddress();
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// push ebp; mov ebp, esp; push ebx; and esp, 0FFFFFFF0h; sub esp, 20h; call $+5; pop ebx
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bytes = new byte[]
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{0x55, 0x89, 0xE5, 0x53, 0x83, 0xE4, 0xF0, 0x83, 0xEC, 0x20, 0xE8, 0x00, 0x00, 0x00, 0x00, 0x5B};
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image.Position = loc;
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buff = image.ReadBytes(16);
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if (!bytes.SequenceEqual(buff))
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return (0, 0);
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// lea eax, (pCgr - offset)[ebx] (Position + 6 is the opcode lea eax; Position + 8 is the operand)
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image.Position += 6;
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// Ensure it's lea eax, #address
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if (image.ReadUInt16() != 0x838D)
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return (0, 0);
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try {
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pCgr = image.MapVATR(image.ReadUInt32() + plt);
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}
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// Could not find a mapping in the section table
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catch (InvalidOperationException) {
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return (0, 0);
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}
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// Extract Metadata pointer
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// An 0x838D opcode indicates LEA (no indirection)
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image.Position = pCgr + 0x20;
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var opcode = image.ReadUInt16();
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metadata = image.ReadUInt32() + plt;
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// An 8x838B opcode indicates MOV (pointer indirection)
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if (opcode == 0x838B) {
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image.Position = image.MapVATR(metadata);
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metadata = image.ReadUInt32();
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}
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if (opcode != 0x838B && opcode != 0x838D)
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return (0, 0);
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// Repeat the same logic for extracting the Code pointer
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image.Position = pCgr + 0x2A;
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opcode = image.ReadUInt16();
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code = image.ReadUInt32() + plt;
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if (opcode == 0x838B) {
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image.Position = image.MapVATR(code);
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code = image.ReadUInt32();
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}
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if (opcode != 0x838B && opcode != 0x838D)
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return (0, 0);
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return (code, metadata);
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}
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return (0, 0);
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}
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}
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}
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