Re: [PATCH v8 0/4] Introduce mseal

[Theo de Raadt]

> What I'm more concerned about is what happens if you call mseal() on a
> range and it can mseal a portion.  Like, what happens to the first vma
> in your test_seal_unmapped_middle case?  I see it returns an error, but
> is the first VMA mseal()'ed? (no it's not, but test that)

That is correct, Liam.

Unix system calls must be atomic.

They either return an error, and that is a promise they made no changes.

Or they do the work required, and then return success.

In OpenBSD, all mimmutable() aspects were carefully studied to gaurantee
this behaviour.

I am not an expert in the Linux kernel to make the assessment; someone
who is qualified must make that assessment.  Fuzzing with tests is a good
way to judge it simpler.