Don't create anonymous namespace (b37c4818) · Commits · e / os / android_system_core

libnativeloader/include/nativeloader/dlext_namespaces.h

+12 −14

Original line number	Diff line number	Diff line
		@@ -22,18 +22,6 @@

		__BEGIN_DECLS

		/*
		* Initializes anonymous namespaces. The shared_libs_sonames is the list of sonames
		* to be shared by default namespace separated by colon. Example: "libc.so:libm.so:libdl.so".
		*
		* The library_search_path is the search path for anonymous namespace. The anonymous namespace
		* is used in the case when linker cannot identify the caller of dlopen/dlsym. This happens
		* for the code not loaded by dynamic linker; for example calls from the mono-compiled code.
		*/
		extern bool android_init_anonymous_namespace(const char* shared_libs_sonames,
		const char* library_search_path);


		enum {
		/* A regular namespace is the namespace with a custom search path that does
		* not impose any restrictions on the location of native libraries.
		@@ -62,8 +50,18 @@ enum {
		*/
		ANDROID_NAMESPACE_TYPE_GREYLIST_ENABLED = 0x08000000,

		ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED \|
		ANDROID_NAMESPACE_TYPE_ISOLATED,
		/* This flag instructs linker to use this namespace as the anonymous
		* namespace. The anonymous namespace is used in the case when linker cannot
		* identify the caller of dlopen/dlsym. This happens for the code not loaded
		* by dynamic linker; for example calls from the mono-compiled code. There can
		* be only one anonymous namespace in a process. If there already is an
		* anonymous namespace in the process, using this flag when creating a new
		* namespace causes an error.
		*/
		ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS = 0x10000000,

		ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED =
		ANDROID_NAMESPACE_TYPE_SHARED \| ANDROID_NAMESPACE_TYPE_ISOLATED,
		};

		/*

libnativeloader/library_namespaces.cpp

+16 −37

Original line number	Diff line number	Diff line
		@@ -159,13 +159,6 @@ Result<NativeLoaderNamespace> LibraryNamespaces::Create(JNIEnv env, uint32_t t
		}
		}

		// Initialize the anonymous namespace with the first non-empty library path.
		Result<void> ret;
		if (!library_path.empty() && !initialized_ &&
		!(ret = InitPublicNamespace(library_path.c_str()))) {
		return ret.error();
		}

		LOG_ALWAYS_FATAL_IF(FindNamespaceByClassLoader(env, class_loader) != nullptr,
		"There is already a namespace associated with this classloader");

		@@ -215,13 +208,22 @@ Result<NativeLoaderNamespace> LibraryNamespaces::Create(JNIEnv env, uint32_t t

		// Create the app namespace
		NativeLoaderNamespace* parent_ns = FindParentNamespaceByClassLoader(env, class_loader);
		auto app_ns =
		NativeLoaderNamespace::Create(namespace_name, library_path, permitted_path, parent_ns,
		is_shared, target_sdk_version < 24 /* is_greylist_enabled */);
		// Heuristic: the first classloader with non-empty library_path is assumed to
		// be the main classloader for app
		// TODO(b/139178525) remove this heuristic by determining this in LoadedApk (or its
		// friends) and then passing it down to here.
		bool is_main_classloader = app_main_namespace_ == nullptr && !library_path.empty();
		// Policy: the namespace for the main classloader is also used as the
		// anonymous namespace.
		bool also_used_as_anonymous = is_main_classloader;
		// Note: this function is executed with g_namespaces_mutex held, thus no
		// racing here.
		auto app_ns = NativeLoaderNamespace::Create(
		namespace_name, library_path, permitted_path, parent_ns, is_shared,
		target_sdk_version < 24 /* is_greylist_enabled */, also_used_as_anonymous);
		if (!app_ns) {
		return app_ns.error();
		}

		// ... and link to other namespaces to allow access to some public libraries
		bool is_bridged = app_ns->IsBridged();

		@@ -278,6 +280,9 @@ Result<NativeLoaderNamespace> LibraryNamespaces::Create(JNIEnv env, uint32_t t
		}

		namespaces_.push_back(std::make_pair(env->NewWeakGlobalRef(class_loader), *app_ns));
		if (is_main_classloader) {
		app_main_namespace_ = &(*app_ns);
		}

		return &(namespaces_.back().second);
		}
		@@ -295,32 +300,6 @@ NativeLoaderNamespace* LibraryNamespaces::FindNamespaceByClassLoader(JNIEnv* env
		return nullptr;
		}

		Result<void> LibraryNamespaces::InitPublicNamespace(const char* library_path) {
		// Ask native bride if this apps library path should be handled by it
		bool is_native_bridge = NativeBridgeIsPathSupported(library_path);

		// (http://b/25844435) - Some apps call dlopen from generated code (mono jited
		// code is one example) unknown to linker in which case linker uses anonymous
		// namespace. The second argument specifies the search path for the anonymous
		// namespace which is the library_path of the classloader.
		initialized_ = android_init_anonymous_namespace(default_public_libraries().c_str(),
		is_native_bridge ? nullptr : library_path);
		if (!initialized_) {
		return Error() << dlerror();
		}

		// and now initialize native bridge namespaces if necessary.
		if (NativeBridgeInitialized()) {
		initialized_ = NativeBridgeInitAnonymousNamespace(default_public_libraries().c_str(),
		is_native_bridge ? library_path : nullptr);
		if (!initialized_) {
		return Error() << NativeBridgeGetError();
		}
		}

		return {};
		}

		NativeLoaderNamespace* LibraryNamespaces::FindParentNamespaceByClassLoader(JNIEnv* env,
		jobject class_loader) {
		jobject parent_class_loader = GetParentClassLoader(env, class_loader);

libnativeloader/library_namespaces.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,7 @@ class LibraryNamespaces {
		void Reset() {
		namespaces_.clear();
		initialized_ = false;
		app_main_namespace_ = nullptr;
		}
		Result<NativeLoaderNamespace> Create(JNIEnv env, uint32_t target_sdk_version,
		jobject class_loader, bool is_shared, jstring dex_path,
		@@ -59,6 +60,7 @@ class LibraryNamespaces {
		NativeLoaderNamespace* FindParentNamespaceByClassLoader(JNIEnv* env, jobject class_loader);

		bool initialized_;
		NativeLoaderNamespace* app_main_namespace_;
		std::list<std::pair<jweak, NativeLoaderNamespace>> namespaces_;
		};

libnativeloader/native_loader_namespace.cpp

+12 −1

Original line number	Diff line number	Diff line
		@@ -85,7 +85,8 @@ Result<NativeLoaderNamespace> NativeLoaderNamespace::GetPlatformNamespace(bool i

		Result<NativeLoaderNamespace> NativeLoaderNamespace::Create(
		const std::string& name, const std::string& search_paths, const std::string& permitted_paths,
		const NativeLoaderNamespace* parent, bool is_shared, bool is_greylist_enabled) {
		const NativeLoaderNamespace* parent, bool is_shared, bool is_greylist_enabled,
		bool also_used_as_anonymous) {
		bool is_bridged = false;
		if (parent != nullptr) {
		is_bridged = parent->IsBridged();
		@@ -100,7 +101,17 @@ Result<NativeLoaderNamespace> NativeLoaderNamespace::Create(
		}
		const NativeLoaderNamespace& effective_parent = parent != nullptr ? parent : platform_ns;

		// All namespaces for apps are isolated
		uint64_t type = ANDROID_NAMESPACE_TYPE_ISOLATED;

		// The namespace is also used as the anonymous namespace
		// which is used when the linker fails to determine the caller address
		if (also_used_as_anonymous) {
		type \|= ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS;
		}

		// Bundled apps have access to all system libraries that are currently loaded
		// in the default namespace
		if (is_shared) {
		type \|= ANDROID_NAMESPACE_TYPE_SHARED;
		}

libnativeloader/native_loader_namespace.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -39,7 +39,8 @@ struct NativeLoaderNamespace {
		const std::string& search_paths,
		const std::string& permitted_paths,
		const NativeLoaderNamespace* parent, bool is_shared,
		bool is_greylist_enabled);
		bool is_greylist_enabled,
		bool also_used_as_anonymous);

		NativeLoaderNamespace(NativeLoaderNamespace&&) = default;
		NativeLoaderNamespace(const NativeLoaderNamespace&) = default;