Re: [PATCH v6 1/7] mseal, system mappings: kernel config and header change

Liam R. Howlett
2025-02-24T19:11:44Z

* Kees Cook <kees@kernel.org> [250224 13:55]:
> On Mon, Feb 24, 2025 at 10:52:13AM -0800, Dave Hansen wrote:
> > On 2/24/25 10:44, Jeff Xu wrote:
> > > For example:
> > > Consider the case below in src/third_party/kernel/v6.6/fs/proc/task_mmu.c,
> > >
> > > #ifdef CONFIG_64BIT
> > > [ilog2(VM_SEALED)] = "sl",
> > > #endif
> > >
> > > Redefining VM_SEALED to VM_NONE for 32 bit won't detect the problem
> > > in case that "#ifdef CONFIG_64BIT" line is missing.
> > >
> > > Please note, this has been like this since the first version of
> > > mseal() RFC patch, and I prefer to keep it this way.
> >
> > That logic is reasonable. But it's different from the _vast_ majority of
> > other flags.
> >
> > So what justifies VM_SEALED being so different? It's leading to pretty
> > objectively ugly code in this series.
>
> Note that VM_SEALED is the "is this VMA sealed?" bit itself. The define
> for "should we perform system mapping sealing?" is intentionally separate
> here, so that it can be Kconfig and per-arch toggled, etc.
>

Considering Dave is the second person that did not find the huge commit
message helpful, can we please limit the commit message to be about the
actual code and not the entire series?

I thought we said that it was worth while making this change in v5?

Thanks,
Liam