[PATCH] regmap: REGMAP_KUNIT must not select REGMAP

[PATCH] regmap: REGMAP_KUNIT must not select REGMAP

[Geert Uytterhoeven]

Enabling a (modular) test must not silently enable additional kernel
functionality, as that may increase the attack vector of a product.

Fix this by making REGMAP_KUNIT depend on REGMAP instead.

Fixes: 2238959b6ad27040 ("regmap: Add some basic kunit tests")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 drivers/base/regmap/Kconfig | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index 33a8366e22a584a5..20327c15cbce5d8c 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -11,9 +11,8 @@ config REGMAP
 
 config REGMAP_KUNIT
 	tristate "KUnit tests for regmap"
-	depends on KUNIT
+	depends on KUNIT && REGMAP
 	default KUNIT_ALL_TESTS
-	select REGMAP
 	select REGMAP_RAM
 
 config REGMAP_AC97
-- 
2.34.1

Re: [PATCH] regmap: REGMAP_KUNIT must not select REGMAP

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 815 bytes --]

On Wed, Apr 26, 2023 at 01:56:44PM +0200, Geert Uytterhoeven wrote:
> Enabling a (modular) test must not silently enable additional kernel
> functionality, as that may increase the attack vector of a product.
> 
> Fix this by making REGMAP_KUNIT depend on REGMAP instead.

This doesn't work since regmap is a selected library so there's no way
to directly enable regmap other than by enabling something that uses it
and it is very likely that the virtual configurations people often use
with KUnit will not have any physical hardware and therefore will not
need regmap.  It seems a lot more likely that someone would want to run
the tests on a platform that doesn't otherwise use regmap than that
someone would end up building in regmap on a production kernel that
wouldn't otherwise have enabled it.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH] regmap: REGMAP_KUNIT must not select REGMAP

[Geert Uytterhoeven]

Hi Mark,

On Wed, Apr 26, 2023 at 2:42 PM Mark Brown <broonie@kernel.org> wrote:
> On Wed, Apr 26, 2023 at 01:56:44PM +0200, Geert Uytterhoeven wrote:
> > Enabling a (modular) test must not silently enable additional kernel
> > functionality, as that may increase the attack vector of a product.
> >
> > Fix this by making REGMAP_KUNIT depend on REGMAP instead.
>
> This doesn't work since regmap is a selected library so there's no way
> to directly enable regmap other than by enabling something that uses it
> and it is very likely that the virtual configurations people often use
> with KUnit will not have any physical hardware and therefore will not
> need regmap.  It seems a lot more likely that someone would want to run
> the tests on a platform that doesn't otherwise use regmap than that
> someone would end up building in regmap on a production kernel that
> wouldn't otherwise have enabled it.

Thanks, I had missed that.  Will send a v2...

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds