[ObjC] Create a shared ObjC processor for Macho and DSC views

Both the Macho and DSC views need to process Objective-C but have separate processor classes. It would appear that the DSC version was largely a copy and paste of the Macho view one, with some modifications. The majority of code overlaps between the 2 so it doesn't make sense to maintain 2 and copy and paste improvements/fixes between them.

This commit fixes that by creating a base Objective-C processor that contains the shared code. View specific code is implemented in the respective subclasses for the views. Although there is very little view specific code for each.

objc/objc.h

@@ -0,0 +1,333 @@
+#pragma once
+
+#include <binaryninjaapi.h>
+
+namespace BinaryNinja {
+	// This set of structs is based on the objc4 source,
+	// 		however pointers have been replaced with view_ptr_t
+
+	// Used for pointers within BinaryView, primarily to make it far more clear in typedefs
+	// 		whether the size of a field can vary between architectures.
+	// These should _not_ be used in sizeof or direct Read() calls.
+	typedef uint64_t view_ptr_t;
+
+	typedef struct {
+		view_ptr_t name;
+		view_ptr_t types;
+		view_ptr_t imp;
+	} method_t;
+	typedef struct {
+		uint32_t name;
+		uint32_t types;
+		uint32_t imp;
+	} method_entry_t;
+	typedef struct {
+		view_ptr_t offset;
+		view_ptr_t name;
+		view_ptr_t type;
+		uint32_t alignmentRaw;
+		uint32_t size;
+	} ivar_t;
+	typedef struct {
+		view_ptr_t name;
+		view_ptr_t attributes;
+	} property_t;
+	typedef struct {
+		uint32_t entsizeAndFlags;
+		uint32_t count;
+	} method_list_t;
+	typedef struct {
+		uint32_t entsizeAndFlags;
+		uint32_t count;
+	} ivar_list_t;
+	typedef struct {
+		uint32_t entsizeAndFlags;
+		uint32_t count;
+	} property_list_t;
+	typedef struct {
+		uint64_t count;
+	} protocol_list_t;
+	struct relative_list_list_entry_t {
+	    uint64_t imageIndex: 16;
+	    int64_t listOffset: 48;
+	};
+	typedef struct {
+		view_ptr_t isa;
+		view_ptr_t mangledName;
+		view_ptr_t protocols;
+		view_ptr_t instanceMethods;
+		view_ptr_t classMethods;
+		view_ptr_t optionalInstanceMethods;
+		view_ptr_t optionalClassMethods;
+		view_ptr_t instanceProperties;
+		uint32_t size;
+		uint32_t flags;
+	} protocol_t;
+	typedef struct {
+		uint32_t flags;
+		uint32_t instanceStart;
+		uint32_t instanceSize;
+		uint32_t reserved;
+		view_ptr_t ivarLayout;
+		view_ptr_t name;
+		view_ptr_t baseMethods;
+		view_ptr_t baseProtocols;
+		view_ptr_t ivars;
+		view_ptr_t weakIvarLayout;
+		view_ptr_t baseProperties;
+	} class_ro_t;
+	typedef struct {
+		view_ptr_t isa;
+		view_ptr_t super;
+		view_ptr_t cache;
+		view_ptr_t vtable;
+		view_ptr_t data;
+	} class_t;
+	typedef struct {
+		view_ptr_t name;
+		view_ptr_t cls;
+		view_ptr_t instanceMethods;
+		view_ptr_t classMethods;
+		view_ptr_t protocols;
+		view_ptr_t instanceProperties;
+	} category_t;
+	typedef struct {
+		view_ptr_t receiver;
+		view_ptr_t current_class;
+	} objc_super2;
+	typedef struct {
+		view_ptr_t imp;
+		view_ptr_t sel;
+	} message_ref_t;
+
+	struct Method {
+		std::string name;
+		std::string types;
+		view_ptr_t imp;
+	};
+
+	struct Ivar {
+		uint32_t offset;
+		std::string name;
+		std::string type;
+		uint32_t alignment;
+		uint32_t size;
+	};
+
+	struct Property {
+		std::string name;
+		std::string attributes;
+	};
+
+	struct ClassBase {
+		std::map<uint64_t, Method> methodList;
+		std::map<uint64_t, Ivar> ivarList;
+	};
+
+	struct Class {
+		std::string name;
+		ClassBase instanceClass;
+		ClassBase metaClass;
+
+		// Loaded by type processing
+		QualifiedName associatedName;
+	};
+
+	class Protocol {
+	public:
+		std::string name;
+		std::vector<QualifiedName> protocols;
+		ClassBase instanceMethods;
+		ClassBase classMethods;
+		ClassBase optionalInstanceMethods;
+		ClassBase optionalClassMethods;
+	};
+
+	struct QualifiedNameOrType {
+		BinaryNinja::Ref<BinaryNinja::Type> type = nullptr;
+		BinaryNinja::QualifiedName name;
+		size_t ptrCount = 0;
+	};
+
+	class ObjCReader {
+	public:
+		/*! Read from the current cursor position into buffer `dest` and advance the cursor that many bytes
+
+		    \throws Exception
+			\param dest Address to write the read bytes to
+			\param len Number of bytes to write
+		*/
+		virtual void Read(void* dest, size_t len) = 0;
+
+		/*! Read a null-terminated string from the current cursor position
+
+		    \throws Exception
+			\return the string
+		*/
+		virtual std::string ReadCString() = 0;
+
+		/*! Read a uint8_t from the current cursor position and advance the cursor by 1 byte
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual uint8_t Read8() = 0;
+
+		/*! Read a uint16_t from the current cursor position and advance the cursor by 2 bytes
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual uint16_t Read16() = 0;
+
+		/*! Read a uint32_t from the current cursor position and advance the cursor by 4 bytes
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual uint32_t Read32() = 0;
+
+		/*! Read a uint64_t from the current cursor position and advance the cursor by 8 bytes
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual uint64_t Read64() = 0;
+
+		/*! Read a int8_t from the current cursor position and advance the cursor by 1 byte
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual int8_t ReadS8() = 0;
+
+		/*! Read a int16_t from the current cursor position and advance the cursor by 2 bytes
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual int16_t ReadS16() = 0;
+
+		/*! Read a int32_t from the current cursor position and advance the cursor by 4 bytes
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual int32_t ReadS32() = 0;
+
+		/*! Read a int64_t from the current cursor position and advance the cursor by 8 bytes
+
+		    \throws Exception
+			\return The read value
+		*/
+		virtual int64_t ReadS64() = 0;
+
+		/*! Read a pointer from the current cursor position and advance it that many bytes
+
+		    \throws Exception
+		    \return The value that was read
+		*/
+		virtual uint64_t ReadPointer() = 0;
+
+		/*! Get the current cursor position
+
+			\return The current cursor position
+		*/
+		virtual uint64_t GetOffset() const = 0;
+
+		/*! Set the cursor position
+
+			\param offset The new cursor position
+		*/
+		virtual void Seek(uint64_t offset) = 0;
+
+		/*! Set the cursor position, relative to the current position
+
+			\param offset Offset to the current cursor position
+		*/
+		virtual void SeekRelative(int64_t offset) = 0;
+	};
+
+	class ObjCProcessor {
+		struct Types {
+			QualifiedName relativePtr;
+			QualifiedName id;
+			QualifiedName sel;
+			QualifiedName BOOL;
+			QualifiedName nsInteger;
+			QualifiedName nsuInteger;
+			QualifiedName cgFloat;
+			QualifiedName cfStringFlag;
+			QualifiedName cfString;
+			QualifiedName cfStringUTF16;
+			QualifiedName imageInfoFlags;
+			QualifiedName imageInfoSwiftVersion;
+			QualifiedName imageInfo;
+			QualifiedName methodEntry;
+			QualifiedName method;
+			QualifiedName methodList;
+			QualifiedName classRO;
+			QualifiedName cls;
+			QualifiedName category;
+			QualifiedName protocol;
+			QualifiedName protocolList;
+			QualifiedName ivar;
+			QualifiedName ivarList;
+		} m_typeNames;
+
+		bool m_isBackedByDatabase;
+		// TODO(WeiN76LQh): this is to avoid a bug with defining a classes protocol list in the DSC plugin. Remove once fixed
+		bool m_skipClassBaseProtocols;
+
+		SymbolQueue* m_symbolQueue = nullptr;
+		std::map<uint64_t, Class> m_classes;
+		std::map<uint64_t, Class> m_categories;
+		std::map<uint64_t, Protocol> m_protocols;
+		std::unordered_map<uint64_t, std::string> m_selectorCache;
+		std::unordered_map<uint64_t, Method> m_localMethods;
+
+		// Required for workflow_objc type heuristics, should be removed when that is no longer a thing.
+		std::map<uint64_t, std::string> m_selRefToName;
+		std::map<uint64_t, std::vector<uint64_t>> m_selRefToImplementations;
+		std::map<uint64_t, std::vector<uint64_t>> m_selToImplementations;
+		// --
+
+		uint64_t ReadPointerAccountingForRelocations(ObjCReader* reader);
+		std::unordered_map<uint64_t, uint64_t> m_relocationPointerRewrites;
+
+		static Ref<Metadata> SerializeMethod(uint64_t loc, const Method& method);
+		static Ref<Metadata> SerializeClass(uint64_t loc, const Class& cls);
+		Ref<Metadata> SerializeMetadata();
+
+		std::vector<QualifiedNameOrType> ParseEncodedType(const std::string& type);
+		void DefineObjCSymbol(BNSymbolType symbolType, QualifiedName typeName, const std::string& name, uint64_t addr, bool deferred);
+		void DefineObjCSymbol(BNSymbolType symbolType, Ref<Type> type, const std::string& name, uint64_t addr, bool deferred);
+		void ReadIvarList(ObjCReader* reader, ClassBase& cls, std::string_view name, view_ptr_t start);
+		void ReadMethodList(ObjCReader* reader, ClassBase& cls, std::string_view name, view_ptr_t start);
+		void ReadListOfMethodLists(ObjCReader* reader, ClassBase& cls, std::string_view name, view_ptr_t start);
+		void LoadClasses(ObjCReader* reader, Ref<Section> listSection);
+		void LoadCategories(ObjCReader* reader, Ref<Section> listSection);
+		void LoadProtocols(ObjCReader* reader, Ref<Section> listSection);
+		void GenerateClassTypes();
+		bool ApplyMethodType(Class& cls, Method& method, bool isInstanceMethod);
+		void ApplyMethodTypes(Class& cls);
+
+		Ref<Section> GetSectionForImage(std::optional<std::string> imageName, const char* sectionName);
+		void PostProcessObjCSections(ObjCReader* reader, std::optional<std::string> imageName);
+
+	protected:
+		Ref<BinaryView> m_data;
+		Ref<Logger> m_logger;
+
+		virtual uint64_t GetObjCRelativeMethodBaseAddress(ObjCReader* reader);
+		virtual void GetRelativeMethod(ObjCReader* reader, method_t& meth);
+		virtual std::shared_ptr<ObjCReader> GetReader() = 0;
+
+	public:
+		ObjCProcessor(BinaryView* data, const char* loggerName, bool isBackedByDatabase, bool skipClassBaseProtocols = false);
+		void ProcessObjCData(std::optional<std::string> imageName);
+		void ProcessCFStrings(std::optional<std::string> imageName);
+		void AddRelocatedPointer(uint64_t location, uint64_t rewrite);
+	};
+}
+

view/macho/CMakeLists.txt

@@ -9,6 +9,7 @@ endif()
 file(GLOB SOURCES
 	*.cpp
 	*.h)
+list(APPEND SOURCES ../../objc/objc.cpp)
 
 if(DEMO)
 	add_library(view_macho STATIC ${SOURCES})

view/macho/machoview.cpp

@@ -1847,13 +1847,13 @@ bool MachoView::InitializeHeader(MachOHeader& header, bool isMainHeader, uint64_
 		parseObjCStructs = settings->Get<bool>("loader.macho.processObjectiveC", this);
 	if (settings && settings->Contains("loader.macho.processCFStrings"))
 		parseCFStrings = settings->Get<bool>("loader.macho.processCFStrings", this);
-	if (!ObjCProcessor::ViewHasObjCMetadata(this))
+	if (!MachoObjCProcessor::ViewHasObjCMetadata(this))
 		parseObjCStructs = false;
 	if (!GetSectionByName("__cfstring"))
 		parseCFStrings = false;
 	if (parseObjCStructs || parseCFStrings)
 	{
-		m_objcProcessor = new ObjCProcessor(this, m_backedByDatabase);
+		m_objcProcessor = new MachoObjCProcessor(this, m_backedByDatabase);
 	}
 	if (parseObjCStructs)
 	{
@@ -2339,7 +2339,7 @@ bool MachoView::InitializeHeader(MachOHeader& header, bool isMainHeader, uint64_
 	if (parseCFStrings)
 	{
 		try {
-			m_objcProcessor->ProcessCFStrings();
+			m_objcProcessor->ProcessCFStrings(std::nullopt);
 		}
 		catch (std::exception& ex)
 		{
@@ -2351,7 +2351,7 @@ bool MachoView::InitializeHeader(MachOHeader& header, bool isMainHeader, uint64_
 	if (parseObjCStructs)
 	{
 		try {
-			m_objcProcessor->ProcessObjCData();
+			m_objcProcessor->ProcessObjCData(std::nullopt);
 		}
 		catch (std::exception& ex)
 		{
@@ -3880,7 +3880,7 @@ Ref<Settings> MachoViewType::GetLoadSettingsForData(BinaryView* data)
 			settings->UpdateProperty(override, "readOnly", false);
 	}
 
-	if (ObjCProcessor::ViewHasObjCMetadata(viewRef))
+	if (MachoObjCProcessor::ViewHasObjCMetadata(viewRef))
 	{
 		settings->RegisterSetting("loader.macho.processObjectiveC",
 			R"({

view/macho/machoview.h

@@ -1330,7 +1330,7 @@ namespace BinaryNinja
 			QualifiedName filesetEntryCommandQualName;
 		} m_typeNames;
 
-		ObjCProcessor* m_objcProcessor = nullptr;
+		MachoObjCProcessor* m_objcProcessor = nullptr;
 
 		uint64_t m_universalImageOffset;
 		bool m_parseOnly, m_backedByDatabase;