CSOLoader is a traceless and system linker independent SOTA custom linker for Android Linux.
- C99 compliant
- System linker independent (no dlopen)
- Dependency-less (no third-party dependency, except system ones)
- Near complete feature parity to AOSP linker
$ git clone https://github.com/ThePedroo/CSOLoader
$ cd CSOLoaderThis is required to test CSOLoader capabilities. Before proceeding, connect your device and assure you can access adb shell.
$ make$ cd shareds
$ make standalone$ adb shell su -c /data/local/tmp/csoloader /data/local/tmp/shared.soCSOLoader aims to provide a simple API to match the as-simple API that system linkers/libdl provides. Currently, there are only 4 user-facing APIs.
In csoloader.c, in STANDALONE_TEST #ifdef, there is a basic usage of CSOLoader. Usage of CSOLoader's csoloader_abandon follows the same as csoloader_unload.
bool csoloader_load(struct csoloader *lib, const char *lib_path)
Loads and links the library into the process' memory, and load the info to the csoloader structure for future management. Returns false if operations fails, and performs cleanup automatically.
bool csoloader_unload(struct csoloader *lib)
Unloads the library from the process' memory from the csoloader structure. Returns false if operations fails, and will leak memory if that happens.
bool csoloader_abandon(struct csoloader *lib)
Frees all internal management handles while allowing it to still continue operation, however, without TLS available. Returns false if operations fails, and will leak memory if that happens.
void *csoloader_get_symbol(struct csoloader *lib, const char *symbol_name)
Gets the symbol address from the loaded library, won't work if the library has been abandoned. Returns NULL if operation failed.
void csoloader_deinit(void)Deinitializes all internal global resources, such as TLS management. This is required to be called if you won't be using CSOLoader anymore, and want to leave no traces behind.
Important
You may also want to define CSOLOADER_MAKE_LINKER_HOOKS macro to make CSOLoader hook some functions that are commonly used by libraries, such as dl_iterate_phdr, dlopen, dlclose, and dladdr. However, doing so, will make so that CSOLoader must be kept loaded, since if CSOLoader is unloaded, it will call an unmapped address. However, even with it not defined, CSOLoader will still hook __tls_get_addr to provide TLS support, so it is better to not use TLS it if you want to use unload CSOLoader and have them work flawlessly.
- Indirect symbol support
- Load and link library's dependencies
- Full relocation support
- Android-specific relocations support
- Memory protection
- Constructors/Deconstructors calling
-
libdlfunctions support (backtrace, dl_iterate_phdr, dladdr) - TLS support
- (EH) Frame register
- C++ exceptions support (testing)
- MTE (tagged-pointer) support
- Support be system linker
-
preinitsupport (needed to be system linker)
The testing file for Android implements testing for almost all supported functionality.
Any question or issue related to CSOLoader or other PerformanC projects can be made in PerformanC's Discord server.
It is mandatory to follow the PerformanC's contribution guidelines to contribute to CSOLoader. Following its Security Policy, Code of Conduct and syntax standard.
CSOLoader is licensed under GNU AGPLv3 License. You can read more about it on Open Source Initiative.
- This project is considered as: leading standard.