711 lines
39 KiB
C#
711 lines
39 KiB
C#
/*
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Copyright 2020 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.Collections.Generic;
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using System.Linq;
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namespace Il2CppInspector
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{
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// Some IL2CPP applications obfuscate the order of fields in Il2CppCodeRegistration and Il2CppMetadataRegistration
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// specifically to defeat IL2CPP reverse engineering tools. We make an imperfect attempt to defeat this below
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// by re-arranging the fields back into their original order. This can be greatly improved and much more deeply analyzed.
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// Devs: Please don't burn development resources on obfuscation. It's a waste of your time and mine. Spend it making good games instead.
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partial class Il2CppBinary
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{
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// Loads all the pointers and counts for the specified IL2CPP metadata type regardless of version or word size into two arrays
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// Sorts the pointers and calculates the maximum number of bytes between each,
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// optinally constrained by the highest count in the IL2CPP metadata type and by the end of the nearest section in the image.
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// Returns an array of the pointers in sorted order and an array of maximum byte/word counts with corresponding indexes
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private (List<ulong> ptrs, List<int> limits, List<int> originalCounts)
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preparePointerList(Type type, ulong typePtr, IEnumerable<Section> sections, bool itemsAreWords = false) {
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// Get number of pointer/count pairs in each structure
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var itemsCount = Metadata.Sizeof(type, Image.Version, Image.Bits / 8) / (Image.Bits / 8) / 2;
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// Read pointers and counts as two lists
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var itemArray = Image.ReadMappedArray<ulong>(typePtr, itemsCount * 2);
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var itemPtrs = Enumerable.Range(0, itemArray.Length / 2).Select(i => itemArray[i*2 + 1]).ToList();
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var itemCounts = Enumerable.Range(0, itemArray.Length / 2).Select(i => (int) itemArray[i*2]).ToList();
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// Get maximum number of bytes/count between each pair of pointers
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// None of the maximums should be higher than the maximum count specified in the struct
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// Rule out zero pointers for no longer used fields (eg. customAttributeGenerators >=27)
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var itemMaxBytes = itemsAreWords? itemCounts.Max() * (Image.Bits / 8) : int.MaxValue;
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var itemPtrsOrdered = itemPtrs.Where(p => p != 0).OrderBy(p => p).ToList();
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var itemCountLimits = itemPtrsOrdered
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.Zip(itemPtrsOrdered.Skip(1), (a, b) => Math.Min((int) (b - a), itemMaxBytes))
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.Append(itemMaxBytes)
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.ToList();
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// Prevent a pointer list from overrunning the end of a section
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for (var i = 0; i < itemPtrsOrdered.Count; i++) {
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var section = sections.FirstOrDefault(s => s.VirtualStart <= itemPtrsOrdered[i] && s.VirtualEnd >= itemPtrsOrdered[i]);
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if (section != null) {
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var maxSize = (int) (section.VirtualEnd + 1 - itemPtrsOrdered[i]);
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itemCountLimits[i] = Math.Min(itemCountLimits[i], maxSize);
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}
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}
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// Convert byte sizes to words if applicable
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if (itemsAreWords)
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itemCountLimits = itemCountLimits.Select(i => i / (Image.Bits / 8)).ToList();
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return (itemPtrsOrdered, itemCountLimits, itemCounts);
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}
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// Reconstruct Il2CppCodeRegistration and Il2CppMetadataRegistration into their original, unobfuscated field order
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// Supports metadata >=19, <27
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private void ReconstructMetadata(Metadata metadata) {
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// If the section table is not available, give up and do nothing
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if (!Image.TryGetSections(out var sections))
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return;
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// Get relevant image sections
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var codeSections = sections.Where(s => s.IsExec).ToList();
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var dataSections = sections.Where(s => s.IsData && !s.IsBSS).ToList();
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var bssSections = sections.Where(s => s.IsBSS).ToList();
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// For PE files, data sections in memory can be larger than in the image
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// The unmapped portion is BSS data so create fake sections for this and shrink the existing ones
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foreach (var section in dataSections) {
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var virtualSize = section.VirtualEnd - section.VirtualStart;
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var imageSize = section.ImageEnd - section.ImageStart;
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if (imageSize < virtualSize) {
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var bssEnd = section.VirtualEnd;
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section.VirtualEnd = section.VirtualStart + imageSize;
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bssSections.Add(new Section {
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VirtualStart = section.VirtualStart + imageSize + 1,
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VirtualEnd = bssEnd,
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ImageStart = 0,
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ImageEnd = 0,
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IsExec = false,
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IsData = false,
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IsBSS = true,
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Name = ".bss"
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});
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}
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}
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// Fetch and sanitize our pointer and count lists
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var (codePtrsOrdered, codeCountLimits, codeCounts) = preparePointerList(typeof(Il2CppCodeRegistration), CodeRegistrationPointer, dataSections, true);
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var (metaPtrsOrdered, metaCountLimits, metaCounts) = preparePointerList(typeof(Il2CppMetadataRegistration), MetadataRegistrationPointer, dataSections);
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// Progress updater
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var maxProgress = codeCounts.Sum() + metaCounts.Sum();
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var currentProgress = 0;
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void UpdateProgress(int workDone) {
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currentProgress += workDone;
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StatusUpdate($"Reconstructing obfuscated registration metadata ({currentProgress * 100 / maxProgress:F0}%)");
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}
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Console.WriteLine("Reconstructing obfuscated registration metadata...");
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UpdateProgress(0);
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// Some heuristic constants
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// Counts from minimal compiles
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// v21 test project:
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// genericMethodPointers - 0x07B5, customAttributeGenerators - 0x0747, invokerPointers - 0x04DB, methodPointers - 0x226A
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// v24.1 empty Unity project:
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// genericMethodPointers - 0x0C15, customAttributeGenerators - 0x0A21, invokerPointers - 0x0646, methodPointers - 0x268B
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// v24.2 without Unity:
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// genericMethodPointers - 0x2EC2, customAttributeGenerators - 0x15EC, invokerPointers - 0x0B65
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// v21 test project:
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// genericInsts - 0x0150, genericMethodTable - 0x0805, types - 0x1509, methodSpecs - 0x08D8, fieldOffsets - 0x0569, metadataUsages - 0x1370
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// v24.1 empty Unity project:
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// genericInsts - 0x025E, genericMethodTable - 0x0E3F, types - 0x2632, methodSpecs - 0x0FD4, fieldOffsets - 0x0839, metadataUsages - 0x1850
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// v24.2 without Unity:
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// genericInsts - 0x06D4, genericMethodTable - 0x31E8, types - 0x318A, methodSpecs - 0x3AD8, fieldOffsets - 0x0B3D, metadataUsages - 0x3BA8
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// The maximum address gap in a sequential list of pointers before the sequence is considered to be 'broken'
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const int MAX_SEQUENCE_GAP = 0x10000;
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// The minimum number of Il2CppTypes we expect
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const int MIN_TYPES = 0x1400;
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// The maximum number of generic type parameters we expect for any class or method
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const int MAX_GENERIC_TYPE_PARAMETERS = 32;
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// The minimum number of Il2CppGenericInsts we expect
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const int MIN_GENERIC_INSTANCES = 0x140;
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// The maximum number of generic methods in generic classes we expect to find in a single sequence of Il2CppMethodSpec
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// The highest we have seen in a production app is 3414; the next highest 2013, the next highest 1380
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// 300-600 is typical
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const int MAX_SEQUENTIAL_GENERIC_CLASS_METHODS = 5000;
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// The minimum number of Il2CppMethodSpecs we expect
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const int MIN_METHOD_SPECS = 0x0800;
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// The minimum number of Il2CppGenericMethodFunctionsDefinitions we expect
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const int MIN_GENERIC_METHOD_TABLE = 0x600;
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// The minimum spread of values in an instance of Il2CppGenericMethodFunctionsDefinitions under which the threshold counter is incremented
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const int MIN_GENERIC_METHOD_TABLE_SPREAD = 100;
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// The maximum number of instances in a row with a spread under the minimum we expect to find in a single sequence
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const int MAX_SEQUENTIAL_GENERIC_METHOD_TABLE_LOW_SPREAD_INSTANCES = 100;
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// The minimum number of field offsets we expect
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const int MIN_FIELD_OFFSETS = 0x400;
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// The maximum value for a field offset
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const int MAX_FIELD_OFFSET = 0x100000;
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// The minimum and maximum proportions of inversions we expect in a non-pointer field offset list
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// Example values: 0.385, 0.415, 0.468
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const double MIN_FIELD_OFFSET_INVERSION = 0.3;
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const double MAX_FIELD_OFFSET_INVERSION = 0.6;
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// The minimum and maximum proportions of zeroes we expect in a non-pointer field offset list
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// Example values: 0.303, 0.321, 0.385
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const double MIN_FIELD_OFFSET_ZEROES = 0.2;
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const double MAX_FIELD_OFFSET_ZEROES = 0.5;
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// Things we need from Il2CppCodeRegistration
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// methodPointers (<=24.1) -> list of function pointers (1st count) (non-sequential)
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// genericMethodPointers -> list of function pointers (first IS zero) (2nd count) (not sequential)
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// customAttributeGenerators (<27) -> list of function pointers (first MAY be zero) (2nd count) (sequential)
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// invokerPointers -> list of function pointers (3rd count) (sequential)
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// codeGenModules (>=24.2) -> list of Il2CppCodeGenModule* // TODO: We only support <=24.1 currently
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// (interopData will probably have 6 sequential pointers since Il2CppInteropData starts with 5 function pointers and a GUID)
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// Let's see how many valid pointers and sequential valid pointers we actually find at each address
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// Scan each pointer address for valid list of function pointers and sort into size order
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// Consider the sequence to be broken if there is a gap over a certain threshold
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var fnPtrs = new SortedDictionary<ulong, int>();
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var seqFnPtrs = new SortedDictionary<ulong, int>();
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for (var i = 0; i < codePtrsOrdered.Count; i++) {
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// Non-sequential valid pointers
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var ptrs = Image.ReadMappedArray<ulong>(codePtrsOrdered[i], codeCountLimits[i]);
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var foundCount = ptrs.TakeWhile(p => codeSections.Any(s => p >= s.VirtualStart && p <= s.VirtualEnd || p == 0)).Count();
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// Prune count of trailing zero pointers
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while (foundCount > 0 && ptrs[foundCount - 1] == 0ul)
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foundCount--;
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fnPtrs.Add(codePtrsOrdered[i], foundCount);
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// Binaries compiled with MSVC (generally PE files) use /OPT:ICF by default (enable ICF) so this won't work.
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// For these binaries, we'll use a different selection strategy below
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if (Image is PEReader)
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continue;
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// Sequential valid pointers (a subset of non-sequential valid pointers)
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if (foundCount > 0) {
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foundCount = ptrs.Take(foundCount)
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.Zip(ptrs.Take(foundCount).Skip(1), (a, b) => (a, b))
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.TakeWhile(t => ((long) t.b - (long) t.a >= 0 || t.b == 0)
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&& ((long) t.b - (long) t.a < MAX_SEQUENCE_GAP || t.a == 0)
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// Disallow two zero pointers in a row
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&& (t.a != 0 || t.b != 0))
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.Count() + 1;
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// Prune count of trailing zero pointers
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while (foundCount > 0 && ptrs[foundCount - 1] == 0ul)
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foundCount--;
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}
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seqFnPtrs.Add(codePtrsOrdered[i], foundCount);
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UpdateProgress(foundCount);
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}
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KeyValuePair<ulong, int> methodPointers, genericMethodPointers, customAttributeGenerators, invokerPointers;
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// Solution without ICF
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if (!(Image is PEReader)) {
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// The two largest sequential groups are customAttributeGenerators and invokerPointers
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var seqLongest = seqFnPtrs.OrderByDescending(kv => kv.Value).Take(2).ToList();
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(customAttributeGenerators, invokerPointers) = (seqLongest[0], seqLongest[1]);
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// For >=27, customAttributeGenerators is zero and so the largest group is invokerPointers
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if (Image.Version >= 27) {
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invokerPointers = customAttributeGenerators;
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customAttributeGenerators = new KeyValuePair<ulong, int>(0ul, 0);
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}
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// After removing these from the non-sequential list, the largest groups are methodPointers and genericMethodPointers
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var longest = fnPtrs.Except(seqLongest).OrderByDescending(kv => kv.Value).Take(2).ToList();
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(methodPointers, genericMethodPointers) = (longest[0], longest[1]);
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// For >=24.2, methodPointers is zero and so the largest group is genericMethodPointers
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if (Image.Version >= 24.2) {
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genericMethodPointers = methodPointers;
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methodPointers = new KeyValuePair<ulong, int>(0ul, 0);
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}
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// Prune genericMethodPointers at 2nd zero (first pointer is always zero)
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var gmPtr = Image.ReadMappedArray<ulong>(genericMethodPointers.Key, genericMethodPointers.Value);
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var gmZero = Array.IndexOf(gmPtr, 0ul, 1);
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if (gmZero != -1)
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genericMethodPointers = new KeyValuePair<ulong, int>(genericMethodPointers.Key, gmZero);
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}
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// Solution with ICF
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else {
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// Take and remove the first item and assume it's methodPointers for <=24.1, otherwise set to zero
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var orderedPtrs = fnPtrs.OrderByDescending(kv => kv.Value).ToList();
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if (Image.Version <= 24.1) {
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methodPointers = orderedPtrs[0];
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orderedPtrs.RemoveAt(0);
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} else
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methodPointers = new KeyValuePair<ulong, int>(0ul, 0);
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// Assume this order is right most of the time
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// TODO: generic and custom attribute might be the wrong way round (eg. #102)
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(genericMethodPointers, customAttributeGenerators, invokerPointers) = (orderedPtrs[0], orderedPtrs[1], orderedPtrs[2]);
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// customAttributeGenerators is removed in metadata >=27
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if (Image.Version >= 27) {
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invokerPointers = customAttributeGenerators;
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customAttributeGenerators = new KeyValuePair<ulong, int>(0ul, 0);
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}
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}
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#region Debugging validation checks
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#if false
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// Used on non-obfuscated binaries during development to confirm the output is correct
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if (methodPointers.Key != CodeRegistration.pmethodPointers)
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throw new Exception("Method Pointers incorrect");
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if (invokerPointers.Key != CodeRegistration.invokerPointers)
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throw new Exception("Invoker Pointers incorrect");
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if (customAttributeGenerators.Key != CodeRegistration.customAttributeGenerators)
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throw new Exception("Custom attribute generators incorrect");
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if (genericMethodPointers.Key != CodeRegistration.genericMethodPointers)
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throw new Exception("Generic method pointers incorrect");
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if (methodPointers.Value != (int) CodeRegistration.methodPointersCount)
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throw new Exception("Count of Method Pointers incorrect");
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if (invokerPointers.Value != (int) CodeRegistration.invokerPointersCount)
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throw new Exception("Count of Invoker Pointers incorrect");
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if (customAttributeGenerators.Value != (int) CodeRegistration.customAttributeCount)
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throw new Exception("Count of Custom attribute generators incorrect");
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if (genericMethodPointers.Value != (int) CodeRegistration.genericMethodPointersCount)
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throw new Exception("Count of Generic method pointers incorrect");
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#endif
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#endregion
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// Perform substitution
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CodeRegistration.genericMethodPointers = genericMethodPointers.Key;
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CodeRegistration.genericMethodPointersCount = (ulong) genericMethodPointers.Value;
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CodeRegistration.customAttributeGenerators = customAttributeGenerators.Key;
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CodeRegistration.customAttributeCount = customAttributeGenerators.Value;
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CodeRegistration.invokerPointers = invokerPointers.Key;
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CodeRegistration.invokerPointersCount = (ulong) invokerPointers.Value;
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CodeRegistration.pmethodPointers = methodPointers.Key;
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CodeRegistration.methodPointersCount = (ulong) methodPointers.Value;
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// Force CodeRegistration to pass validation in Il2CppBinary.Configure()
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CodeRegistration.reversePInvokeWrapperCount = 0;
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CodeRegistration.unresolvedVirtualCallCount = 0;
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CodeRegistration.interopDataCount = 0;
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// Things we need from Il2CppMetadataRegistration
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// genericInsts -> list of Il2CppGenericInst* (argc is count of Il2CppType* at data pointer argv; datapoint = GenericParameterIndex)
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// genericMethodTable -> list of Il2CppGenericMethodFunctionsDefinitions (genericMethodIndex, methodIndex, invokerIndex)
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// types -> list of Il2CppType*
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// methodSpecs -> list of Il2CppMethodSpec
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// methodReferences (<=16) -> list of uint (ignored, we don't support <=16 here)
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// fieldOffsets (fieldOffsetsArePointers) -> either a list of data pointers (some zero, some VAs not mappable) to list of uints, or a list of uints
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// metadataUsages (>=19, <27) -> list of unmappable data pointers
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// We can only perform this re-ordering if we can refer to a loaded global-metadata.dat
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if (metadata == null)
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return;
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// Read in all the required data once since we'll be using nested loops
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var metaPtrData = new List<(ulong, int, ulong[], int)>();
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for (var i = 0; i < metaPtrsOrdered.Count; i++) {
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// Pointers in this list
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var ptrs = Image.ReadMappedArray<ulong>(metaPtrsOrdered[i], metaCountLimits[i] / (Image.Bits / 8));
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// First set of pointers that point to a data section virtual address
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var foundDataPtrsCount = ptrs.TakeWhile(p => dataSections.Any(s => p >= s.VirtualStart && p <= s.VirtualEnd)).Count();
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// First set of pointers that can be mapped anywhere into the image
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var foundImageMappablePtrsCount = ptrs.TakeWhile(p => Image.TryMapVATR(p, out _)).Count();
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#if DEBUG
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// First set of pointers that can be mapped into a data section in the image
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var mappableDataPtrs = ptrs.Take(foundImageMappablePtrsCount)
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.TakeWhile(p => dataSections.Any(s => Image.MapVATR(p) >= s.ImageStart && Image.MapVATR(p) <= s.ImageEnd))
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.ToArray();
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var foundNonBSSDataPtrsCount = mappableDataPtrs.Length;
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if (foundDataPtrsCount != foundNonBSSDataPtrsCount)
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throw new Exception($"Pointer count mismatch: {foundDataPtrsCount:x8} / {foundNonBSSDataPtrsCount:x8}");
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#endif
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metaPtrData.Add((metaPtrsOrdered[i], metaCountLimits[i], ptrs, foundDataPtrsCount));
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}
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// Items we need to search for
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var types = (ptr: 0ul, count: -1);
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var genericInsts = (ptr: 0ul, count: -1);
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var methodSpecs = (ptr: 0ul, count: -1);
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var genericMethodTable = (ptr: 0ul, count: -1);
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var metadataUsages = (ptr: 0ul, count: -1);
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var fieldOffsets = (ptr: 0ul, count: -1);
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var NOT_FOUND = (ptr: 0xfffffffful, count: -1);
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// Intermediary items
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var typesPtrs = new List<ulong>();
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Il2CppMethodSpec[] methodSpec = null;
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// IL2CPP doesn't calculate metadataUsagesCount correctly so we do it here
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// Adapted from Il2CppInspector.buildMetadataUsages()
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var usages = new HashSet<uint>();
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// Only on supported metadata versions (>=19, <27)
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if (metadata.MetadataUsageLists != null)
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foreach (var metadataUsageList in metadata.MetadataUsageLists)
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for (var i = 0; i < metadataUsageList.count; i++)
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usages.Add(metadata.MetadataUsagePairs[metadataUsageList.start + i].destinationindex);
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// Determine what each pointer is
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// We need to do this in a certain order because validating some items relies on earlier items
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while (metaPtrData.Any()) {
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ref var foundItem = ref NOT_FOUND;
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(ulong ptr, int count) foundData = (0ul, -1);
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// We loop repeatedly through every set of data looking for our next target item,
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// remove the matching set from the list and then repeat the outer while loop
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// until there is nothing left to find
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foreach (var (ptr, limit, ptrs, dataPtrsCount) in metaPtrData) {
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foundData = (ptr, 0);
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// Test for Il2CppType**
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// ---------------------
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if (types.count == -1) {
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// We don't ever expect there to be less than MIN_TYPES types
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if (dataPtrsCount >= MIN_TYPES) {
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var testItems = Image.ReadMappedObjectPointerArray<Il2CppType>(ptr, dataPtrsCount);
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foreach (var item in testItems) {
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// TODO: v27 will fail this because of the bit shifting in Il2CppType.bits
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if (item.num_mods != 0)
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break;
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if (!Enum.IsDefined(typeof(Il2CppTypeEnum), item.type))
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break;
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if (item.type == Il2CppTypeEnum.IL2CPP_TYPE_END)
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break;
|
|
|
|
// Test datapoint
|
|
if (item.type switch {
|
|
var t when (t is Il2CppTypeEnum.IL2CPP_TYPE_VALUETYPE || t is Il2CppTypeEnum.IL2CPP_TYPE_CLASS)
|
|
&& item.datapoint >= (ulong) metadata.Types.Length => false,
|
|
|
|
var t when (t is Il2CppTypeEnum.IL2CPP_TYPE_VAR || t is Il2CppTypeEnum.IL2CPP_TYPE_MVAR)
|
|
&& item.datapoint >= (ulong) metadata.GenericParameters.Length => false,
|
|
|
|
var t when (t is Il2CppTypeEnum.IL2CPP_TYPE_PTR || t is Il2CppTypeEnum.IL2CPP_TYPE_SZARRAY)
|
|
&& !ptrs.Take(dataPtrsCount).Contains(item.datapoint) => false,
|
|
|
|
// Untested cases, we could add more here (IL2CPP_TYPE_ARRAY, IL2CPP_TYPE_GENERICINST)
|
|
_ => true
|
|
})
|
|
foundData.count++;
|
|
else
|
|
break;
|
|
}
|
|
|
|
if (foundData.count >= MIN_TYPES) {
|
|
foundItem = ref types;
|
|
typesPtrs = ptrs.ToList();
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Test for Il2CppGenericInst**
|
|
// ----------------------------
|
|
else if (genericInsts.count == -1) {
|
|
|
|
if (dataPtrsCount >= MIN_GENERIC_INSTANCES) {
|
|
|
|
var testItems = Image.ReadMappedObjectPointerArray<Il2CppGenericInst>(ptr, dataPtrsCount);
|
|
|
|
foreach (var item in testItems) {
|
|
// Let's pray no generic type has more than this many type parameters
|
|
if (item.type_argc > MAX_GENERIC_TYPE_PARAMETERS)
|
|
break;
|
|
|
|
// All the generic type paramters must be in the total list of types,
|
|
// ie. typePtrs must be a subset of typesData.Keys
|
|
try {
|
|
var typePtrs = Image.ReadMappedArray<ulong>(item.type_argv, (int) item.type_argc);
|
|
if (typePtrs.Any(p => !typePtrs.Contains(p)))
|
|
break;
|
|
// Pointers were invalid
|
|
}
|
|
catch (InvalidOperationException) {
|
|
break;
|
|
}
|
|
|
|
foundData.count++;
|
|
}
|
|
|
|
if (foundData.count >= MIN_GENERIC_INSTANCES) {
|
|
foundItem = ref genericInsts;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Test for Il2CppMethodSpec*
|
|
// --------------------------
|
|
else if (methodSpecs.count == -1) {
|
|
var max = limit / metadata.Sizeof(typeof(Il2CppMethodSpec));
|
|
|
|
if (max >= MIN_METHOD_SPECS) {
|
|
|
|
var testItems = Image.ReadMappedArray<Il2CppMethodSpec>(ptr, max);
|
|
var nonNegativePairs = 0;
|
|
|
|
foreach (var item in testItems) {
|
|
if (item.methodDefinitionIndex < 0 || item.methodDefinitionIndex >= metadata.Methods.Length)
|
|
break;
|
|
if (item.classIndexIndex < -1 || item.classIndexIndex >= genericInsts.count)
|
|
break;
|
|
if (item.methodIndexIndex < -1 || item.methodIndexIndex >= genericInsts.count)
|
|
break;
|
|
|
|
// Non-negative pairs shouldn't appear in large groups
|
|
nonNegativePairs = item.classIndexIndex != -1 && item.methodIndexIndex != -1 ? nonNegativePairs + 1 : 0;
|
|
if (nonNegativePairs > MAX_SEQUENTIAL_GENERIC_CLASS_METHODS)
|
|
break;
|
|
|
|
foundData.count++;
|
|
}
|
|
|
|
// Assumes last methods are not generic methods in generic classes
|
|
foundData.count -= nonNegativePairs;
|
|
|
|
if (foundData.count >= MIN_METHOD_SPECS) {
|
|
foundItem = ref methodSpecs;
|
|
methodSpec = testItems;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Test for Il2CppGenericMethodFunctionsDefinitions*
|
|
// -------------------------------------------------
|
|
else if (genericMethodTable.count == -1) {
|
|
var max = limit / metadata.Sizeof(typeof(Il2CppGenericMethodFunctionsDefinitions));
|
|
|
|
if (max >= MIN_GENERIC_METHOD_TABLE) {
|
|
|
|
var testItems = Image.ReadMappedArray<Il2CppGenericMethodFunctionsDefinitions>(ptr, max);
|
|
var lowSpreadCount = 0;
|
|
|
|
foreach (var item in testItems) {
|
|
if (item.genericMethodIndex < 0 || item.genericMethodIndex >= methodSpecs.count)
|
|
break;
|
|
if (item.indices.methodIndex < 0 || item.indices.methodIndex >= genericMethodPointers.Value)
|
|
break;
|
|
if (item.indices.invokerIndex < 0 || item.indices.invokerIndex >= invokerPointers.Value)
|
|
break;
|
|
// methodIndex is an index into the method pointer table
|
|
// For generic type definitions, there is no concrete function so this must be 0xffffffff
|
|
// TODO: For >=24.2, we need to use the method token to look up the value in an Il2CppCodeGenModule, not currently implemented
|
|
if (Image.Version <= 24.1)
|
|
if (metadata.Methods[methodSpec[item.genericMethodIndex].methodDefinitionIndex].methodIndex != -1)
|
|
break;
|
|
foundData.count++;
|
|
|
|
// Instances where all the values are clustered should be rare
|
|
var spread = Math.Max(Math.Max(item.indices.methodIndex, item.indices.invokerIndex), item.genericMethodIndex)
|
|
- Math.Min(Math.Min(item.indices.methodIndex, item.indices.invokerIndex), item.genericMethodIndex);
|
|
|
|
lowSpreadCount = spread < MIN_GENERIC_METHOD_TABLE_SPREAD ? lowSpreadCount + 1 : 0;
|
|
if (lowSpreadCount > MAX_SEQUENTIAL_GENERIC_METHOD_TABLE_LOW_SPREAD_INSTANCES)
|
|
break;
|
|
}
|
|
|
|
// Assumes the last instances don't have clustered values
|
|
foundData.count -= lowSpreadCount;
|
|
|
|
if (foundData.count >= MIN_GENERIC_METHOD_TABLE) {
|
|
foundItem = ref genericMethodTable;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Test for metadata usages
|
|
// ------------------------
|
|
else if (metadataUsages.count == -1) {
|
|
|
|
// No metadata usages for these versions
|
|
if (Image.Version < 19 || Image.Version >= 27) {
|
|
foundData.ptr = 0ul;
|
|
foundItem = ref metadataUsages;
|
|
break;
|
|
}
|
|
|
|
// Metadata usages always map to BSS sections and has only a maximum of a small number of null pointers
|
|
if (dataPtrsCount == 0 && limit / (Image.Bits / 8) >= usages.Count) {
|
|
|
|
// No null pointers allowed
|
|
if (ptrs.Take(usages.Count).All(p => p != 0ul)) {
|
|
|
|
// All the pointers must map to a BSS section
|
|
// For PE files this relies on our section modding above
|
|
var bssMappableCount = ptrs.Take(usages.Count).Count(p => bssSections.Any(s => p >= s.VirtualStart && p <= s.VirtualEnd));
|
|
|
|
foundData.count = bssMappableCount;
|
|
foundItem = ref metadataUsages;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Test for field offsets
|
|
// ----------------------
|
|
else if (fieldOffsets.count == -1) {
|
|
// This could be a list of pointers to locally incrementing sequences of uints,
|
|
// or it could be a sequence of uints
|
|
|
|
// Some uints may be zero, but must otherwise never be less than the minimum heap offset of the first parameter
|
|
// for the binary's function calling convention, and never greater than the maximum heap offset of the last parameter
|
|
|
|
// Try as sequence of uints
|
|
var max = limit / sizeof(uint);
|
|
|
|
if (max >= MIN_FIELD_OFFSETS) {
|
|
|
|
var testItems = Image.ReadMappedArray<uint>(ptr, max);
|
|
var previousItem = 0u;
|
|
var inversions = 0;
|
|
var zeroes = 0;
|
|
|
|
foreach (var item in testItems) {
|
|
if (item > MAX_FIELD_OFFSET && item != 0xffffffff)
|
|
break;
|
|
// Count zeroes and inversions (equality counts as inversion here since two arguments can't share a heap offset)
|
|
if (item <= previousItem)
|
|
inversions++;
|
|
if (item == 0)
|
|
zeroes++;
|
|
previousItem = item;
|
|
|
|
foundData.count++;
|
|
}
|
|
|
|
if (foundData.count >= MIN_FIELD_OFFSETS) {
|
|
var inversionsPc = (double) inversions / foundData.count;
|
|
var zeroesPc = (double) zeroes / foundData.count;
|
|
|
|
if (inversionsPc >= MIN_FIELD_OFFSET_INVERSION && inversionsPc <= MAX_FIELD_OFFSET_INVERSION
|
|
&& zeroesPc >= MIN_FIELD_OFFSET_ZEROES && zeroesPc <= MAX_FIELD_OFFSET_ZEROES) {
|
|
foundItem = ref fieldOffsets;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
foundData = (0ul, -1);
|
|
}
|
|
|
|
// We didn't find anything - break to avoid an infinite loop
|
|
if (foundItem == NOT_FOUND)
|
|
break;
|
|
|
|
// Remove pointer from list of remaining pointers to test
|
|
metaPtrData = metaPtrData.Where(m => foundData.ptr != m.Item1).ToList();
|
|
|
|
// Select the highest count in the original data that is lower or equal to our found count
|
|
// Skip items not implemented by the specific metadata version we are analyzing (ptr == 0, count == 0)
|
|
// Skip metadataUsages because it is calculated incorrectly by IL2CPP and the count is wrong
|
|
if (foundData.count > 0 && foundData.count != usages.Count) {
|
|
// Aggregate uses the first value for 'next' as the seed for 'nearest' unless we specify a starting seed
|
|
foundData.count = metaCounts.Aggregate(0, (nearest, next) => next - foundData.count > nearest - foundData.count && next - foundData.count <= 0? next : nearest);
|
|
metaCounts = metaCounts.Where(c => c != foundData.count).ToList();
|
|
}
|
|
|
|
// Set item via ref
|
|
foundItem = foundData;
|
|
|
|
// If we just found the Il2CppTypes data, prune the pointer list to the correct length
|
|
if (foundItem == types && typesPtrs.Count != foundData.count)
|
|
typesPtrs = typesPtrs.Take(foundData.count).ToList();
|
|
|
|
UpdateProgress(foundData.count);
|
|
}
|
|
|
|
#region Debugging validation checks
|
|
#if false
|
|
// Used on non-obfuscated binaries during development to confirm the output is correct
|
|
if (types.ptr != MetadataRegistration.ptypes)
|
|
throw new Exception("Il2CppType** incorrect");
|
|
if (genericInsts.ptr != MetadataRegistration.genericInsts)
|
|
throw new Exception("Il2CppGenericInst** incorrect");
|
|
if (methodSpecs.ptr != MetadataRegistration.methodSpecs)
|
|
throw new Exception("Il2CppMethodSpec* incorrect");
|
|
if (genericMethodTable.ptr != MetadataRegistration.genericMethodTable)
|
|
throw new Exception("Il2CppGenericMethodFunctionsDefinitions* incorrect");
|
|
if (metadataUsages.ptr != MetadataRegistration.metadataUsages)
|
|
throw new Exception("Metadata usages pointer incorrect");
|
|
if (fieldOffsets.ptr != MetadataRegistration.pfieldOffsets)
|
|
throw new Exception("Field offsets pointer incorrect");
|
|
|
|
if (types.count != MetadataRegistration.typesCount)
|
|
throw new Exception("Count of Il2CppType* incorrect");
|
|
if (genericInsts.count != MetadataRegistration.genericInstsCount)
|
|
throw new Exception("Count of Il2CppGenericInst* incorrect");
|
|
if (methodSpecs.count != MetadataRegistration.methodSpecsCount)
|
|
throw new Exception("Count of Il2CppMethodSpec incorrect");
|
|
if (genericMethodTable.count != MetadataRegistration.genericMethodTableCount)
|
|
throw new Exception("Count of Il2CppGenericMethodFunctionsDefinitions");
|
|
if (metadataUsages.count != usages.Count)
|
|
throw new Exception("Count of metadata usages incorrect");
|
|
if (fieldOffsets.count != MetadataRegistration.fieldOffsetsCount)
|
|
throw new Exception("Count of field offsets incorrect");
|
|
#endif
|
|
#endregion
|
|
|
|
// Perform substitution
|
|
MetadataRegistration.ptypes = types.ptr;
|
|
MetadataRegistration.typesCount = types.count;
|
|
MetadataRegistration.genericInsts = genericInsts.ptr;
|
|
MetadataRegistration.genericInstsCount = genericInsts.count;
|
|
MetadataRegistration.methodSpecs = methodSpecs.ptr;
|
|
MetadataRegistration.methodSpecsCount = methodSpecs.count;
|
|
MetadataRegistration.genericMethodTable = genericMethodTable.ptr;
|
|
MetadataRegistration.genericMethodTableCount = genericMethodTable.count;
|
|
MetadataRegistration.metadataUsages = metadataUsages.ptr;
|
|
MetadataRegistration.metadataUsagesCount = (ulong) metadataUsages.count;
|
|
MetadataRegistration.pfieldOffsets = fieldOffsets.ptr;
|
|
MetadataRegistration.fieldOffsetsCount = fieldOffsets.count;
|
|
|
|
// Force MetadataRegistration to pass validation in Il2CppBinary.Configure()
|
|
MetadataRegistration.typeDefinitionsSizesCount = 0;
|
|
MetadataRegistration.genericClassesCount = MetadataRegistration.genericInstsCount + 1;
|
|
|
|
StatusUpdate("Analyzing IL2CPP image");
|
|
}
|
|
}
|
|
} |