2023-09-23 00:30:34

by Kees Cook

Subject: [PATCH] video: fbdev: mmp: Annotate struct mmphw_ctrl with __counted_by

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 mmphw_ctrl.

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

Cc: Helge Deller <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
index 167585a889d3..719b99a9bc77 100644
--- a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
+++ b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
@@ -1406,7 +1406,7 @@ struct mmphw_ctrl {

/*pathes*/
int path_num;
- struct mmphw_path_plat path_plats[];
+ struct mmphw_path_plat path_plats[] __counted_by(path_num);
};

static inline int overlay_is_vid(struct mmp_overlay *overlay)
--
2.34.1

2023-09-23 17:42:47

by Gustavo A. R. Silva

Subject: Re: [PATCH] video: fbdev: mmp: Annotate struct mmphw_ctrl with __counted_by

On 9/22/23 11:51, 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 mmphw_ctrl.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Helge Deller <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

> ---
> drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
> index 167585a889d3..719b99a9bc77 100644
> --- a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
> +++ b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
> @@ -1406,7 +1406,7 @@ struct mmphw_ctrl {
>
> /*pathes*/
> int path_num;
> - struct mmphw_path_plat path_plats[];
> + struct mmphw_path_plat path_plats[] __counted_by(path_num);
> };
>
> static inline int overlay_is_vid(struct mmp_overlay *overlay)

2023-09-24 03:41:56

by Helge Deller

Subject: Re: [PATCH] video: fbdev: mmp: Annotate struct mmphw_ctrl with __counted_by

On 9/23/23 18:33, Gustavo A. R. Silva wrote:
> On 9/22/23 11:51, 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 mmphw_ctrl.
>>
>> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>>
>> Cc: Helge Deller <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Signed-off-by: Kees Cook <[email protected]>
>
> Reviewed-by: Gustavo A. R. Silva <[email protected]>

Both fbdev patches applied to fbdev git tree.

Thank you Kees!

Helge