Re: [PATCH v38 10/24] mm: Add vm_ops->mprotect()

Jarkko Sakkinen
2020-09-24T21:55:36Z

On Thu, Sep 24, 2020 at 02:11:37PM -0500, Haitao Huang wrote:
> > For me this has caused months of confusion and misunderstanding of this
> > feature. I only recently realized that "oh, right, we invented this".
> >
> > They are contrived scenarios enough that they should be considered when
> > the workloads hit.
> >
> > Either we fully support noexec or not at all. Any "partial" thing is a
> > two edged sword: it can bring some robustness with the price of
> > complexity and possible unknown uknown scenarios where they might become
> > API issue.
> >
> > I rather think later on how to extend API in some way to enable such
> > contrivid scenarios rather than worrying about how this could be abused.
> >
> > The whole SGX is complex beast already so lets not add any extra when
> > there is no a hard requirement to do so.
> >
> > I'll categorically deny noexec in the next patch set version.
> >
> > /Jarkko
>
> There are use cases supported currently in which enclave binary is received
> via IPC/RPC and held in buffers before EADD. Denying noexec altogether would
> break those, right?

I do not see why data cannot be provided at run-time. AFAIK, it is not
different from executables how this works when it comes to noexec.

/Jarkko