Re: [v2,0/3] module: Add compile-time check for embedded NUL characters

[Kees Cook <kees@kernel.org>]

On Mon, Oct 20, 2025 at 08:35:53PM +0200, Ricardo Ribalda wrote:
> Hi Kees
> 
> On Mon, 20 Oct 2025 at 20:29, Kees Cook <kees@kernel.org> wrote:
> >
> > On Wed, Oct 15, 2025 at 09:33:40AM +0200, Ricardo Ribalda wrote:
> > > Hi Dan
> > >
> > > On Tue, 14 Oct 2025 at 22:45, Kees Cook <kees@kernel.org> wrote:
> > > >
> > > > On Tue, Oct 14, 2025 at 08:24:00AM +0200, Ricardo Ribalda wrote:
> > > > > Hi Kees
> > > > >
> > > > > Thanks for the report.
> > > > >
> > > > >
> > > > > On Tue, 14 Oct 2025 at 07:41, Kees Cook <kees@kernel.org> wrote:
> > > > > >
> > > > > >
> > > > > >
> > > > > > On October 13, 2025 1:34:20 PM PDT, Patchwork Integration <patchwork@media-ci.org> wrote:
> > > > > > >Dear Kees Cook:
> > > > > > >
> > > > > > >Thanks for your patches! Unfortunately the Media CI robot detected some
> > > > > > >issues:
> > > > > > >
> > > > > > ># Test static:test-smatch
> > > > > > >
> > > > > > >drivers/media/usb/usbtv/usbtv-core.c:157:1: error: bad constant expression
> > > > > >
> > > > > > Where can I find what this test actually does?
> > > > > >
> > > > > > >For more details, check the full report at:
> > > > > > >https://linux-media.pages.freedesktop.org/-/users/patchwork/-/jobs/85913402/artifacts/report.htm .
> > > > > >
> > > > > > This webserver appears to be misconfigured to send compressed output without the right headers? I can't actually view this URL.
> > > > >
> > > > > I will follow-up with fdo maintainers to figure out what happened.
> > > > > there. On the meantime you can use these url that seems to work:
> > > > > https://linux-media.pages.freedesktop.org/-/users/patchwork/-/jobs/85913402/artifacts/report.txt
> > > > > https://gitlab.freedesktop.org/linux-media/users/patchwork/-/jobs/85913398
> > > > >
> > > > > Basically sparse/smatch do not seem to understand the constant.
> > > >
> > > > Yeah, I managed to find the actual scripts that are run for the
> > > > static-sparse/smatch tests. It looks like those tools aren't correctly
> > > > handling string literals for __builtin_strlen(), which is a constant for
> > > > constant arguments.
> > > >
> > > > So, that's a C parsing bug in those tools (GCC and Clang are fine).
> > >
> > > Could you take a look at this patch:
> > > https://patchwork.linuxtv.org/project/linux-media/patch/20251010030610.3032147-3-kees@kernel.org/
> > >
> > > Seems that sparse/smatch are not very happy about __builtin_strlen()
> > >
> > > Could you fix support for __builtin_strlen() in your tool?
> > >
> > > Once Kees lands his patch it will break all the CIs using
> > > sparse/smatch, including media-ci.
> > >
> > > Eg:
> > >
> > > drivers/media/pci/zoran/zr36060.c:33:1: error: bad constant expression
> > > drivers/media/usb/pvrusb2/pvrusb2-dvb.c:19:1: error: bad constant expression
> > > drivers/media/usb/pvrusb2/pvrusb2-dvb.c:19:1: error: bad constant expression
> >
> > We've waited a decade to get the embedded-NUL check into the modinfo
> > macros, so I'm happy to wait until we can get the CI tooling updated.
> 
> For media-ci. It will probably be after 6.19rc1
> 
> Basically, when
> https://lore.kernel.org/linux-sparse/CACePvbVG2KrGQq4cNKV=wbO5h=jp3M0RO1SdfX8kV4OukjPG8A@mail.gmail.com/T/#t
> lands in media-committers.

That's external to Linux, though; it's a patch for sparse and smatch. How
often does the CI rebuild sparse and smatch?

> How did you plan to land this series? via which tree?

I assume it would go either via the modules tree or the hardening tree.
(Again, no rush.)

> if Chris have not landed his fix yet, maybe you can include that patch
> in your series as 1/X.... That will make every ci happy

Since it's a patch for a separate project, I don't think that will work.
(Maybe I'm misunderstanding something?)

-Kees

-- 
Kees Cook