Re: [PATCH v6 7/7] mseal, system mappings: update mseal.rst

Jeff Xu
2025-02-24T21:07:10Z

On Mon, Feb 24, 2025 at 12:26 PM Liam R. Howlett
<Liam.Howlett@oracle.com> wrote:
>
> * jeffxu@chromium.org <jeffxu@chromium.org> [250224 12:45]:
> > From: Jeff Xu <jeffxu@chromium.org>
> >
> > Update memory sealing documentation to include details about system
> > mappings.
> >
> > Signed-off-by: Jeff Xu <jeffxu@chromium.org>
> > ---
> > Documentation/userspace-api/mseal.rst | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/mseal.rst b/Documentation/userspace-api/mseal.rst
> > index 41102f74c5e2..10147281bf2d 100644
> > --- a/Documentation/userspace-api/mseal.rst
> > +++ b/Documentation/userspace-api/mseal.rst
> > @@ -130,6 +130,13 @@ Use cases
> >
> > - Chrome browser: protect some security sensitive data structures.
>
> Did you mean to drop this line?
>
Ah, thank you for catching that.

-Jeff

> >
> > +- System mappings:
> > + If supported by an architecture (via CONFIG_ARCH_HAS_MSEAL_SYSTEM_MAPPINGS),
> > + the CONFIG_MSEAL_SYSTEM_MAPPINGS seals system mappings, e.g. vdso, vvar,
> > + uprobes, sigpage, vectors, etc. CHECKPOINT_RESTORE, UML, gVisor, rr are
> > + known to relocate or unmap system mapping, therefore this config can't be
> > + enabled universally.
> > +
> > When not to use mseal
> > =====================
> > Applications can apply sealing to any virtual memory region from userspace,
> > --
> > 2.48.1.601.g30ceb7b040-goog
> >