How to back up private branches in git

I have a local branch for day-to-day dev work in git. My workflow is:

1. Do stuff on local_branch, commit
2. Fetch origin/master
3. Rebase local_branch to catch up with new stuff from origin/master

It all works fine, however most of the recommendations I encountered say that one should not "push" private branches, on which rebase is regularly performed.

The problem here is that in this case local branch is not backed up to a server and the only way to save the work is to merge it back to "pushable" branch (i.e. origin/master)

What would be your recommendations on the workflow in this case?

Thanks!

UPDATE: I realised that one of the original requirements I had (avoiding usage of external utilities) is unnecessary limiting.

My current solution is to store all my repositories in a cloud-synchronised folder - this way I get backup for free.