Le 15/05/2025 à 15:30, Danill Klimuk a écrit :
Hello everyone. I have received a request to write a Linux kernel module that will wipe any processes leftovers from userspace RAM during/before Linux kernel shutdown/reboot/halt sequences. The reason I am going to do it inside a module is to do it in a more deterministic way that does not depend on any processes. AFAIK Linux kernel does not have any other functionalities to wipe leftovers from RAM apart from the command line arguments "init_on_free" and "init_on_alloc" that results in memory poisoning only during memory allocation and memory deallocation. These arguments cause the kernel to clean processes memory several times during runtime, that is not deterministic because of processes non-deterministic behavior. Hence, I want to bring the memory wiping mechanism in one place and make it more deterministic. The question is: Maybe the Linux kernel already have such functionalities implemented?
Linux memory management topics should be sent to linux...@kvack.org
Currently I am planning to implement the wiping process to be triggered by "reboot_notifier_callback", so to wipe RAM after PID 1 process finishes and no other processes are executing. I am looking forward to merging the module into Linux kernel upstream too.
What do you mean by 'wiping', do you mean 'clearing' ? Can you explain the reason this is needed ? Christophe
