Sargun Dhillon wrote: > > Remove SECURITY_HOOK_COUNT and "struct security_hook_list"->owner and > > the exception in randomize_layout_plugin.c because preventing module > > unloading won't work as expected. > > > > Rather than completely removing the unloading code, might it make > sense to add a BUG_ON or WARN_ON, in security_delete_hooks if > allow_unload_module is false, and owner is not NULL?
Do we need to check ->owner != NULL? Although it will be true that SELinux's ->owner == NULL and LKM-based LSM module's ->owner != NULL, I think we unregister SELinux before setting allow_unload_module to false. Thus, rejecting delete_security_hooks() if allow_unload_module == false will be sufficient. SELinux might want to call panic() if delete_security_hooks() did not unregister due to allow_unload_module == false. Also, allow_unload_module would be renamed to allow_unregister_module. By the way, please don't use BUG_ON() or WARN_ON() because syzbot would hit and call panic() because syzbot runs tests with panic_on_warn == true.