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Merged
AriusII merged 1 commit into from
Sep 21, 2026
Merged

Enforce recursive Client API type boundaries #46

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2 changes: 1 addition & 1 deletion ...enerators/CheatEngine.Client.SourceGenerators.Lua/AnalyzerReleases.Unshipped.md
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Original file line number Diff line number Diff line change
Expand Up @@ -13,4 +13,4 @@
CECLUA1103 | CheatEngine.Client.Lua | Error | Generated Lua operation signatures must be bounded.
CECLUA1104 | CheatEngine.Client.Lua | Error | Non-scalar Lua operation results require a mapper.
CECLUA1105 | CheatEngine.Client.Lua | Error | A Lua operation mapper must match the SDK result.
CECLUA1106 | CheatEngine.Client.Lua | Error | A Lua mapper must project a safe Client result.
CECLUA1106 | CheatEngine.Client.Lua | Error | A Lua mapper must project a safe, recursively closed Client result and source graph.
337 changes: 325 additions & 12 deletions source-generators/CheatEngine.Client.SourceGenerators.Lua/CheatEngineLuaGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,38 @@ public sealed class CheatEngineLuaGenerator : IIncrementalGenerator
private const string LuaFunctionAttributeMetadataName = "CheatEngine.SDK.Annotations.Lua.LuaFunctionAttribute";
private const string LuaGlobalAttributeMetadataName = "CheatEngine.SDK.Annotations.Lua.LuaGlobalAttribute";
private const string LuaResultMapperMetadataName = "CheatEngine.Client.Lua.ILuaResultMapper<TSource, TResult>";
private const string LuaClassAttributeMetadataName = "CheatEngine.SDK.Annotations.Lua.LuaClassAttribute";
private const string CheatEngineSdkAssemblyPrefix = "CheatEngine.SDK";
private const string CheatEngineSdkObjectContractMetadataName =
"CheatEngine.SDK.Engine.Objects.ICEObject<TSelf>";
private const int ClientBoundaryMaximumDepth = 32;
private const int ClientBoundaryMaximumNodes = 256;

private static readonly HashSet<string> ApprovedSdkClientResultTypes = new(StringComparer.Ordinal)
{
"CheatEngine.SDK.Engine.AddressList.MemoryRecordId",
"CheatEngine.SDK.Engine.Enums.FastScanMethod",
"CheatEngine.SDK.Engine.Enums.VariableType",
"CheatEngine.SDK.Engine.Inspection.AddressResolutionOptions",
"CheatEngine.SDK.Engine.Inspection.MemoryRegionInfo",
"CheatEngine.SDK.Engine.Inspection.ModuleInfo",
"CheatEngine.SDK.Engine.Inspection.ModuleName",
"CheatEngine.SDK.Engine.Inspection.ModuleSectionInfo",
"CheatEngine.SDK.Engine.Inspection.SymbolExpression",
"CheatEngine.SDK.Engine.Inspection.SymbolInfo",
"CheatEngine.SDK.Engine.Inspection.TargetProcessId",
"CheatEngine.SDK.Engine.Runtime.CheatEngineArchitecture",
"CheatEngine.SDK.Engine.Runtime.CheatEngineVersion",
"CheatEngine.SDK.Engine.Runtime.PointerSize",
"CheatEngine.SDK.Engine.Runtime.RuntimeCapabilityAvailability",
"CheatEngine.SDK.Engine.Runtime.RuntimeCapabilityId",
"CheatEngine.SDK.Engine.Runtime.TargetAbi",
"CheatEngine.SDK.Engine.Scanning.Aob.AobPattern",
"CheatEngine.SDK.Engine.Scanning.Aob.AobScanOptions",
"CheatEngine.SDK.Engine.Scanning.Values.FirstScanRequest",
"CheatEngine.SDK.Engine.Scanning.Values.NextScanRequest",
"CheatEngine.SDK.Engine.Values.Address"
};

/// <inheritdoc />
public void Initialize(IncrementalGeneratorInitializationContext context)
Expand Down Expand Up @@ -428,23 +460,296 @@ SpecialType.System_UInt64 or SpecialType.System_Single or SpecialType.System_Dou
};
}

private static bool IsSafeMapperSource(ITypeSymbol type)
private static bool TryFindClientBoundaryViolation(ITypeSymbol type, ClientBoundaryRole role,
out string violation)
{
HashSet<ISymbol> visited = new(SymbolEqualityComparer.Default);
int visitedCount = 0;
string rootPath = role == ClientBoundaryRole.MapperSource ? "mapper source" : "mapper result";
return TryFindClientBoundaryViolation(type, role, rootPath, visited, ref visitedCount, 0, out violation);
}

private static bool TryFindClientBoundaryViolation(ITypeSymbol type, ClientBoundaryRole role, string path,
HashSet<ISymbol> visited, ref int visitedCount, int depth, out string violation)
{
if (depth > ClientBoundaryMaximumDepth || ++visitedCount > ClientBoundaryMaximumNodes)
{
violation = path + " exceeds the supported Client result type graph budget.";
return true;
}

if (!visited.Add(type))
{
violation = string.Empty;
return false;
}

if (type.TypeKind == TypeKind.Error || type.TypeKind == TypeKind.Dynamic)
{
violation = path + " uses an unresolved or dynamic type.";
return true;
}

if (type is IFunctionPointerTypeSymbol)
{
violation = path + " exposes a function pointer.";
return true;
}

if (type is IPointerTypeSymbol)
{
violation = path + " exposes a pointer.";
return true;
}

if (type.IsRefLikeType)
{
violation = path + " exposes a ref-like type.";
return true;
}

if (type is IArrayTypeSymbol array)
{
return TryFindClientBoundaryViolation(array.ElementType, role, path + "[]", visited, ref visitedCount,
depth + 1, out violation);
}

if (type is ITypeParameterSymbol typeParameter)
{
return TryFindConstraintViolation(typeParameter, role, path, visited, ref visitedCount, depth, out violation);
}

if (type is not INamedTypeSymbol named)
{
violation = path + " uses an unsupported type shape '" + TypeName(type) + "'.";
return true;
}

if (TryFindNamedTypeViolation(named, role, path, out violation))
{
return true;
}

foreach (ITypeParameterSymbol parameter in named.OriginalDefinition.TypeParameters
.OrderBy(static candidate => candidate.Ordinal))
{
if (TryFindConstraintViolation(parameter, role, path + "." + parameter.Name, visited, ref visitedCount,
depth + 1, out violation))
{
return true;
}
}

if (named.IsTupleType)
{
foreach (IFieldSymbol element in named.TupleElements)
{
if (TryFindClientBoundaryViolation(element.Type, role, path + "." + element.Name, visited,
ref visitedCount, depth + 1, out violation))
{
return true;
}
}
}

foreach (ITypeSymbol argument in named.TypeArguments)
{
if (TryFindClientBoundaryViolation(argument, role, path + "<" + TypeName(argument) + ">", visited,
ref visitedCount, depth + 1, out violation))
{
return true;
}
}

if (IsFrameworkOrApprovedSdkValue(named) ||
(role == ClientBoundaryRole.MapperSource && IsCheatEngineSdkType(named)))
{
violation = string.Empty;
return false;
}

return TryFindUserDefinedDtoViolation(named, role, path, visited, ref visitedCount, depth, out violation);
}

private static bool TryFindNamedTypeViolation(INamedTypeSymbol type, ClientBoundaryRole role, string path,
out string violation)
{
string metadataName = type.OriginalDefinition.ToDisplayString();
if (metadataName is "CheatEngine.SDK.Lua.State.LuaState" or "CheatEngine.SDK.Lua.References.LuaRef" or
"CheatEngine.SDK.Engine.Objects.CEObject" or "CheatEngine.SDK.Engine.Objects.Owned<T>" ||
type.ContainingNamespace.ToDisplayString().Contains(".Interop", StringComparison.Ordinal) ||
HasAttribute(type, LuaClassAttributeMetadataName) || ImplementsSdkObjectContract(type))
{
violation = path + " exposes forbidden SDK lifetime or interop type '" + metadataName + "'.";
return true;
}

if (type.TypeKind == TypeKind.Delegate)
{
violation = path + " exposes a delegate or callback.";
return true;
}

if (role == ClientBoundaryRole.ClientResult &&
type.ContainingAssembly?.Name.StartsWith(CheatEngineSdkAssemblyPrefix, StringComparison.Ordinal) == true &&
!ApprovedSdkClientResultTypes.Contains(metadataName))
{
violation = path + " exposes non-approved SDK type '" + metadataName + "'.";
return true;
}

if (type.SpecialType == SpecialType.System_Object || metadataName == "System.Type")
{
violation = path + " exposes an unqualified object or runtime type.";
return true;
}

violation = string.Empty;
return false;
}

private static bool TryFindConstraintViolation(ITypeParameterSymbol typeParameter, ClientBoundaryRole role,
string path, HashSet<ISymbol> visited, ref int visitedCount, int depth, out string violation)
{
return !IsRawLuaOrOwnershipType(type) && type.TypeKind != TypeKind.Pointer && !type.IsRefLikeType;
foreach (ITypeSymbol constraint in typeParameter.ConstraintTypes.OrderBy(TypeName, StringComparer.Ordinal))
{
if (TryFindClientBoundaryViolation(constraint, role, path + " constraint", visited, ref visitedCount,
depth + 1, out violation))
{
return true;
}
}

violation = string.Empty;
return false;
}

private static bool IsSafeClientResult(ITypeSymbol type)
private static bool TryFindUserDefinedDtoViolation(INamedTypeSymbol type, ClientBoundaryRole role, string path,
HashSet<ISymbol> visited, ref int visitedCount, int depth, out string violation)
{
return IsSafeMapperSource(type) && !HasAttribute(type, "CheatEngine.SDK.Annotations.Lua.LuaClassAttribute");
if (type.BaseType is { SpecialType: not SpecialType.System_Object } baseType &&
TryFindClientBoundaryViolation(baseType, role, path + ".base", visited, ref visitedCount, depth + 1,
out violation))
{
return true;
}

foreach (INamedTypeSymbol implementedInterface in type.Interfaces.OrderBy(TypeName, StringComparer.Ordinal))
{
if (TryFindClientBoundaryViolation(implementedInterface, role, path + ".interface", visited,
ref visitedCount, depth + 1, out violation))
{
return true;
}
}

foreach (ISymbol member in type.GetMembers().OrderBy(static candidate => candidate.MetadataName,
StringComparer.Ordinal))
{
switch (member)
{
case IFieldSymbol { IsStatic: false } field:
if (TryFindClientBoundaryViolation(field.Type, role, path + "." + field.Name, visited,
ref visitedCount, depth + 1, out violation))
{
return true;
}

break;
case IPropertySymbol { IsStatic: false } property:
if (TryFindClientBoundaryViolation(property.Type, role, path + "." + property.Name, visited,
ref visitedCount, depth + 1, out violation) ||
TryFindParameterViolation(property.Parameters, role, path + "." + property.Name, visited,
ref visitedCount, depth + 1, out violation))
{
return true;
}

break;
case IEventSymbol { IsStatic: false } @event:
if (TryFindClientBoundaryViolation(@event.Type, role, path + "." + @event.Name, visited,
ref visitedCount, depth + 1, out violation))
{
return true;
}

break;
case IMethodSymbol { IsStatic: false } method when !method.IsImplicitlyDeclared &&
method.DeclaredAccessibility != Accessibility.Private:
violation = string.Empty;
if (method.ReturnsByRef || method.ReturnsByRefReadonly ||
TryFindClientBoundaryViolation(method.ReturnType, role, path + "." + method.Name, visited,
ref visitedCount, depth + 1, out violation) ||
TryFindParameterViolation(method.Parameters, role, path + "." + method.Name, visited,
ref visitedCount, depth + 1, out violation))
{
violation = string.IsNullOrEmpty(violation)
? path + "." + method.Name + " exposes a by-reference return."
: violation;
return true;
}

break;
}
}

violation = string.Empty;
return false;
}

private static bool TryFindParameterViolation(ImmutableArray<IParameterSymbol> parameters, ClientBoundaryRole role,
string path, HashSet<ISymbol> visited, ref int visitedCount, int depth, out string violation)
{
foreach (IParameterSymbol parameter in parameters.OrderBy(static candidate => candidate.Ordinal))
{
if (parameter.RefKind != RefKind.None)
{
violation = path + " parameter '" + parameter.Name + "' is passed by reference.";
return true;
}

if (TryFindClientBoundaryViolation(parameter.Type, role, path + " parameter '" + parameter.Name + "'",
visited, ref visitedCount, depth + 1, out violation))
{
return true;
}
}

violation = string.Empty;
return false;
}

private static bool IsRawLuaOrOwnershipType(ITypeSymbol type)
private static bool IsFrameworkOrApprovedSdkValue(INamedTypeSymbol type)
{
string metadataName = type.OriginalDefinition.ToDisplayString();
return string.Equals(metadataName, "CheatEngine.SDK.Lua.State.LuaState", StringComparison.Ordinal) ||
string.Equals(metadataName, "CheatEngine.SDK.Lua.References.LuaRef", StringComparison.Ordinal) ||
string.Equals(metadataName, "CheatEngine.SDK.Engine.Objects.CEObject", StringComparison.Ordinal) ||
string.Equals(metadataName, "CheatEngine.SDK.Engine.Objects.Owned<T>", StringComparison.Ordinal);
if (ApprovedSdkClientResultTypes.Contains(metadataName))
{
return true;
}

string? assemblyName = type.ContainingAssembly?.Name;
return assemblyName is not null &&
!assemblyName.StartsWith(CheatEngineSdkAssemblyPrefix, StringComparison.Ordinal) &&
(assemblyName.StartsWith("System", StringComparison.Ordinal) ||
assemblyName.StartsWith("Microsoft", StringComparison.Ordinal));
}

private static bool IsCheatEngineSdkType(INamedTypeSymbol type)
{
return type.ContainingAssembly?.Name.StartsWith(CheatEngineSdkAssemblyPrefix, StringComparison.Ordinal) == true;
}

private static bool ImplementsSdkObjectContract(INamedTypeSymbol type)
{
return type.AllInterfaces.Any(@interface =>
string.Equals(@interface.OriginalDefinition.ToDisplayString(), CheatEngineSdkObjectContractMetadataName,
StringComparison.Ordinal));
}

private enum ClientBoundaryRole
{
MapperSource,
ClientResult
}

private static string TypeDeclaration(INamedTypeSymbol type, bool isStatic)
Expand Down Expand Up @@ -793,9 +1098,17 @@ method.PartialImplementationPart is not null || method.ReturnsByRef || method.Re
{
return Invalid(OperationDiagnosticDescriptors.InvalidMapper, location, mapper.Name, method.Name);
}
else if (!IsSafeMapperSource(sourceResult) || !IsSafeClientResult(result))
else if (TryFindClientBoundaryViolation(sourceResult, ClientBoundaryRole.MapperSource,
out string sourceViolation))
{
return Invalid(OperationDiagnosticDescriptors.UnsafeMappedType, location, method.Name,
sourceViolation);
}
else if (TryFindClientBoundaryViolation(result, ClientBoundaryRole.ClientResult,
out string resultViolation))
{
return Invalid(OperationDiagnosticDescriptors.UnsafeMappedType, location, method.Name);
return Invalid(OperationDiagnosticDescriptors.UnsafeMappedType, location, method.Name,
resultViolation);
}

string operationTypeName = method.Name + "LuaOperation";
Expand Down Expand Up @@ -918,7 +1231,7 @@ private static class OperationDiagnosticDescriptors

public static readonly DiagnosticDescriptor UnsafeMappedType = new(
"CECLUA1106", "Lua operation mapper must project a safe Client result",
"Lua operation '{0}' maps a raw Lua, ownership, pointer, ref-like, or borrowed Lua-class value across the Client boundary",
"Lua operation '{0}' maps an unsafe value across the Client boundary: {1}",
"CheatEngine.Client.Lua", DiagnosticSeverity.Error, true);
}

Expand Down
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