Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct bios_args.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Jorge Lopez <jorge.lopez2@hp.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <markgross@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: platform-driver-x86@vger.kernel.org
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
index dea54f35b8b5..4da99cb7218d 100644
--- a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
+++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
@@ -19,7 +19,7 @@ struct bios_args {
 	u32 command;
 	u32 commandtype;
 	u32 datasize;
-	u8 data[];
+	u8 data[] __counted_by(datasize);
 };
 
 /**
-- 
2.34.1

On Fri, 22 Sep 2023 10:54:21 -0700, Kees Cook wrote:

> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct bios_args.
> 
> [...]


Thank you for your contribution, it has been applied to my local
review-ilpo branch. Note it will show up in the public
platform-drivers-x86/review-ilpo branch only once I've pushed my
local branch there, which might take a while.

Once I've run some tests on the review-ilpo branch the patches
there will be added to the platform-drivers-x86/for-next branch
and eventually will be included in the pdx86 pull-request to
Linus for the next merge-window.

The list of commits applied:
[1/1] platform/x86: hp-bioscfg: Annotate struct bios_args with __counted_by
      commit: 55ec81f7517fad09135f65552cea0a3ee84fff30

--
 i.

On Fri, Sep 22, 2023 at 10:54:21AM -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct bios_args.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Jorge Lopez <jorge.lopez2@hp.com>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Mark Gross <markgross@kernel.org>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Tom Rix <trix@redhat.com>
> Cc: platform-driver-x86@vger.kernel.org
> Cc: llvm@lists.linux.dev
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>  drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> index dea54f35b8b5..4da99cb7218d 100644
> --- a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> @@ -19,7 +19,7 @@ struct bios_args {
>  	u32 command;
>  	u32 commandtype;
>  	u32 datasize;
> -	u8 data[];
> +	u8 data[] __counted_by(datasize);
>  };
>  
>  /**
> -- 
> 2.34.1
> 
>