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Plugins: Simplify event data; add GetStrings and GetStringLiterals

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This commit is contained in:
Katy Coe
2020-12-21 22:54:01 +01:00
parent fbc8e0950c
commit 3e27cd25e9
5 changed files with 112 additions and 79 deletions
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98
Il2CppInspector.Common/IL2CPP/Metadata.cs
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@@ -43,7 +43,7 @@ namespace Il2CppInspector
public uint[] VTableMethodIndices { get; set; }
public string[] StringLiterals { get; set; }
public Dictionary<int, string> Strings { get; } = new Dictionary<int, string>();
public Dictionary<int, string> Strings { get; private set; } = new Dictionary<int, string>();
// Set if something in the metadata has been modified / decrypted
public bool IsModified { get; private set; } = false;
@@ -97,7 +97,7 @@ namespace Il2CppInspector
// in the header after the sanity and version fields, and since it will always point directly to the first byte after the end of the header,
// we can use this value to determine the actual header length and therefore narrow down the metadata version to 24.0/24.1 or 24.2.
if (!pluginResult.AdditionalData.SkipValidation) {
if (!pluginResult.SkipValidation) {
var realHeaderLength = Header.stringLiteralOffset;
if (realHeaderLength != Sizeof(typeof(Il2CppGlobalMetadataHeader))) {
@@ -169,15 +169,20 @@ namespace Il2CppInspector
AttributeTypeRanges = ReadArray<Il2CppCustomAttributeTypeRange>(Header.attributesInfoOffset, Header.attributesInfoCount / Sizeof(typeof(Il2CppCustomAttributeTypeRange)));
}
// Get all metadata string literals
Position = Header.stringOffset;
// Get all metadata strings
var pluginGetStringsResult = PluginHooks.GetStrings(this);
if (pluginGetStringsResult.IsHandled)
Strings = pluginGetStringsResult.Strings;
// Naive implementation: this works for normal IL2CPP metadata but isn't good enough when the strings are encrypted
while (Position < Header.stringOffset + Header.stringCount)
Strings.Add((int)Position - Header.stringOffset, ReadNullTerminatedString());
else {
Position = Header.stringOffset;
// To check for encryption, find every single string start position by scanning all of the definitions
var stringOffsets =
// Naive implementation: this works for normal IL2CPP metadata but isn't good enough when the strings are encrypted
while (Position < Header.stringOffset + Header.stringCount)
Strings.Add((int) Position - Header.stringOffset, ReadNullTerminatedString());
// To check for encryption, find every single string start position by scanning all of the definitions
var stringOffsets =
Images.Select(x => x.nameIndex)
.Concat(Assemblies.Select(x => x.aname.nameIndex))
.Concat(Assemblies.Select(x => x.aname.cultureIndex))
@@ -195,50 +200,57 @@ namespace Il2CppInspector
.Distinct()
.ToList();
// Now confirm that all the keys are present
// If they aren't, that means one or more of the null terminators wasn't null, indicating potential encryption
// Only do this if we need to because it's very slow
if (Header.stringCount > 0 && stringOffsets.Except(Strings.Keys).Any()) {
// Now confirm that all the keys are present
// If they aren't, that means one or more of the null terminators wasn't null, indicating potential encryption
// Only do this if we need to because it's very slow
if (Header.stringCount > 0 && stringOffsets.Except(Strings.Keys).Any()) {
Console.WriteLine("Decrypting strings...");
StatusUpdate("Decrypting strings");
Console.WriteLine("Decrypting strings...");
StatusUpdate("Decrypting strings");
// There may be zero-padding at the end of the last string since counts seem to be word-aligned
// Find the true location one byte after the final character of the final string
var endOfStrings = Header.stringCount;
while (ReadByte(Header.stringOffset + endOfStrings - 1) == 0)
endOfStrings--;
// There may be zero-padding at the end of the last string since counts seem to be word-aligned
// Find the true location one byte after the final character of the final string
var endOfStrings = Header.stringCount;
while (ReadByte(Header.stringOffset + endOfStrings - 1) == 0)
endOfStrings--;
// Start again
Strings.Clear();
Position = Header.stringOffset;
// Start again
Strings.Clear();
Position = Header.stringOffset;
// Read in all of the strings as if they are fixed length rather than null-terminated
foreach (var offset in stringOffsets.Zip(stringOffsets.Skip(1).Append(endOfStrings), (a, b) => (current: a, next: b))) {
var encryptedString = ReadBytes(offset.next - offset.current - 1);
// Read in all of the strings as if they are fixed length rather than null-terminated
foreach (var offset in stringOffsets.Zip(stringOffsets.Skip(1).Append(endOfStrings), (a, b) => (current: a, next: b))) {
var encryptedString = ReadBytes(offset.next - offset.current - 1);
// The null terminator is the XOR key
var xorKey = ReadByte();
// The null terminator is the XOR key
var xorKey = ReadByte();
var decryptedString = Encoding.GetString(encryptedString.Select(b => (byte) (b ^ xorKey)).ToArray());
Strings.Add(offset.current, decryptedString);
var decryptedString = Encoding.GetString(encryptedString.Select(b => (byte) (b ^ xorKey)).ToArray());
Strings.Add(offset.current, decryptedString);
}
// Write changes back in case the user wants to save the metadata file
Position = Header.stringOffset;
foreach (var str in Strings.OrderBy(s => s.Key))
WriteNullTerminatedString(str.Value);
Flush();
IsModified = true;
}
// Write changes back in case the user wants to save the metadata file
Position = Header.stringOffset;
foreach (var str in Strings.OrderBy(s => s.Key))
WriteNullTerminatedString(str.Value);
Flush();
IsModified = true;
}
// Get all managed code string literals
var stringLiteralList = ReadArray<Il2CppStringLiteral>(Header.stringLiteralOffset, Header.stringLiteralCount / Sizeof(typeof(Il2CppStringLiteral)));
// Get all string literals
var pluginGetStringLiteralsResult = PluginHooks.GetStringLiterals(this);
if (pluginGetStringLiteralsResult.IsHandled)
StringLiterals = pluginGetStringLiteralsResult.StringLiterals.ToArray();
StringLiterals = new string[stringLiteralList.Length];
for (var i = 0; i < stringLiteralList.Length; i++)
StringLiterals[i] = ReadFixedLengthString(Header.stringLiteralDataOffset + stringLiteralList[i].dataIndex, stringLiteralList[i].length);
else {
var stringLiteralList = ReadArray<Il2CppStringLiteral>(Header.stringLiteralOffset, Header.stringLiteralCount / Sizeof(typeof(Il2CppStringLiteral)));
StringLiterals = new string[stringLiteralList.Length];
for (var i = 0; i < stringLiteralList.Length; i++)
StringLiterals[i] = ReadFixedLengthString(Header.stringLiteralDataOffset + stringLiteralList[i].dataIndex, stringLiteralList[i].length);
}
// Post-processing hook
IsModified |= PluginHooks.PostProcessMetadata(this).IsStreamModified;

16
Il2CppInspector.Common/Plugins/API/V100/Hooks.cs
View File

@@ -28,6 +28,22 @@ namespace Il2CppInspector.PluginAPI.V100
void PostProcessMetadata(Metadata metadata, PluginPostProcessMetadataEventInfo data);
}
/// <summary>
/// Fetch all of the .NET identifier strings
/// </summary>
public interface IGetStrings
{
void GetStrings(Metadata metadata, PluginGetStringsEventInfo data);
}
/// <summary>
/// Fetch all of the (constant) string literals
/// </summary>
public interface IGetStringLiterals
{
void GetStringLiterals(Metadata metadata, PluginGetStringLiteralsEventInfo data);
}
/// <summary>
/// Post-process the .NET type model to make changes after it has been fully created
/// </summary>

62
Il2CppInspector.Common/Plugins/API/V100/PluginEventInfo.cs
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@@ -10,20 +10,11 @@ using System.Text;
namespace Il2CppInspector.PluginAPI.V100
{
public interface IPluginEventInfo
{
public bool IsHandled { get; set; }
public bool IsInvalid { get; set; }
public bool IsDataModified { get; set; }
public bool IsStreamModified { get; set; }
public PluginErrorEventArgs Error { get; set; }
}
/// <summary>
/// Object which allows plugins to report on what has happened during a call
/// Changes made to this object propagate to the next plugin in the call chain until IsHandled is set to true
/// </summary>
public class PluginEventInfo<T> : IPluginEventInfo where T : new()
public class PluginEventInfo
{
/// <summary>
/// A plugin should set this if it has processed the supplied data in such a way that no further processing is required by other plugins
@@ -53,45 +44,52 @@ namespace Il2CppInspector.PluginAPI.V100
/// </summary>
public bool IsStreamModified { get; set; } = false;
/// <summary>
/// Event-specific additional options and controls. See the documentation for each event for more details.
/// </summary>
public T AdditionalData { get; } = new T();
/// <summary>
/// This wiil be set automatically by Il2CppInspector to the last exception thrown by a plugin for the current event
/// </summary>
public PluginErrorEventArgs Error { get; set; } = null;
}
/// <summary>
/// Generic event info with no additional paramters
/// </summary>
public class PluginEventInfo : PluginEventInfo<object> { }
/// <summary>
/// Event info for PreProcessMetadata
/// </summary>
public class PluginPreProcessMetadataEventInfo : PluginEventInfo<PluginPreProcessMetadataEventData> { }
public class PluginPreProcessMetadataEventInfo : PluginEventInfo
{
/// <summary>
/// Set to true to disable some validation checks by Il2CppInspector that the metadata is valid
/// </summary>
public bool SkipValidation { get; set; }
}
/// <summary>
/// Event info for PostProcessMetadata
/// </summary>
public class PluginPostProcessMetadataEventInfo : PluginEventInfo { }
/// <summary>
/// Event info for GetStrings
/// </summary>
public class PluginGetStringsEventInfo : PluginEventInfo
{
/// <summary>
/// All of the fetched strings to be returned
/// </summary>
public Dictionary<int, string> Strings { get; set; } = new Dictionary<int, string>();
}
/// <summary>
/// Event info for GetStringLiterals
/// </summary>
public class PluginGetStringLiteralsEventInfo : PluginEventInfo
{
/// <summary>
/// All of the fetched string literals to be returned
/// </summary>
public List<string> StringLiterals { get; set; } = new List<string>();
}
/// <summary>
/// Event info for PostProcessTypeModel
/// </summary>
public class PluginPostProcessTypeModelEventInfo : PluginEventInfo { }
/// <summary>
/// Additional data for PreProcessMetadata
/// </summary>
public class PluginPreProcessMetadataEventData
{
/// <summary>
/// Set to true to disable some validation checks by Il2CppInspector that the metadata is valid
/// </summary>
public bool SkipValidation { get; set; }
}
}

13
Il2CppInspector.Common/Plugins/PluginHooks.cs
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@@ -15,16 +15,23 @@ namespace Il2CppInspector
// Hooks we provide to plugins which can choose whether or not to provide implementations
internal static class PluginHooks
{
public static PluginPostProcessMetadataEventInfo PostProcessMetadata(Metadata metadata)
=> PluginManager.Try<IPostProcessMetadata, PluginPostProcessMetadataEventInfo>((p, e) => p.PostProcessMetadata(metadata, e));
public static PluginPreProcessMetadataEventInfo PreProcessMetadata(BinaryObjectStream stream)
=> PluginManager.Try<IPreProcessMetadata, PluginPreProcessMetadataEventInfo>((p, e) => {
stream.Position = 0;
p.PreProcessMetadata(stream, e);
});
public static PluginPostProcessMetadataEventInfo PostProcessMetadata(Metadata metadata)
=> PluginManager.Try<IPostProcessMetadata, PluginPostProcessMetadataEventInfo>((p, e) => p.PostProcessMetadata(metadata, e));
public static PluginGetStringsEventInfo GetStrings(Metadata metadata)
=> PluginManager.Try<IGetStrings, PluginGetStringsEventInfo>((p, e) => p.GetStrings(metadata, e));
public static PluginGetStringLiteralsEventInfo GetStringLiterals(Metadata metadata)
=> PluginManager.Try<IGetStringLiterals, PluginGetStringLiteralsEventInfo>((p, e) => p.GetStringLiterals(metadata, e));
public static PluginPostProcessTypeModelEventInfo PostProcessTypeModel(TypeModel typeModel)
=> PluginManager.Try<IPostProcessTypeModel, PluginPostProcessTypeModelEventInfo>((p, e) => p.PostProcessTypeModel(typeModel, e));
}
}

2
Il2CppInspector.Common/Plugins/PluginManager.cs
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@@ -209,7 +209,7 @@ namespace Il2CppInspector
// Try to cast each enabled plugin to a specific interface type, and for those supporting the interface, execute the supplied delegate
// Errors will be forwarded to the error handler
internal static E Try<I, E>(Action<I, E> action) where E : IPluginEventInfo, new()
internal static E Try<I, E>(Action<I, E> action) where E : PluginEventInfo, new()
{
var eventInfo = new E();