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 mt76_rx_tid.

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

Cc: Felix Fietkau <nbd@nbd.name>
Cc: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: Ryder Lee <ryder.lee@mediatek.com>
Cc: Shayne Chen <shayne.chen@mediatek.com>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: linux-wireless@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mediatek@lists.infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/net/wireless/mediatek/mt76/mt76.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index e8757865a3d0..03ef617b1527 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -376,7 +376,7 @@ struct mt76_rx_tid {
 
 	u8 started:1, stopped:1, timer_pending:1;
 
-	struct sk_buff *reorder_buf[];
+	struct sk_buff *reorder_buf[] __counted_by(size);
 };
 
 #define MT_TX_CB_DMA_DONE		BIT(0)
-- 
2.34.1

On Fri, Sep 15, 2023 at 01:06:12PM -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 mt76_rx_tid.

Friendly ping. Can this get picked up by the wifi tree, or should it go
via something else?

Thanks!

-Kees

> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Felix Fietkau <nbd@nbd.name>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Cc: Ryder Lee <ryder.lee@mediatek.com>
> Cc: Shayne Chen <shayne.chen@mediatek.com>
> Cc: Sean Wang <sean.wang@mediatek.com>
> Cc: Kalle Valo <kvalo@kernel.org>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Cc: linux-wireless@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-mediatek@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/net/wireless/mediatek/mt76/mt76.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
> index e8757865a3d0..03ef617b1527 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76.h
> +++ b/drivers/net/wireless/mediatek/mt76/mt76.h
> @@ -376,7 +376,7 @@ struct mt76_rx_tid {
>  
>  	u8 started:1, stopped:1, timer_pending:1;
>  
> -	struct sk_buff *reorder_buf[];
> +	struct sk_buff *reorder_buf[] __counted_by(size);
>  };
>  
>  #define MT_TX_CB_DMA_DONE		BIT(0)
> -- 
> 2.34.1
> 

-- 
Kees Cook

Kees Cook <keescook@chromium.org> writes:

> On Fri, Sep 15, 2023 at 01:06:12PM -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 mt76_rx_tid.
>
> Friendly ping. Can this get picked up by the wifi tree, or should it go
> via something else?

It's already in mt76 pull request and should be in wireless-next next
week:

https://patchwork.kernel.org/project/linux-wireless/patch/a5a2baaa-0db4-403e-9ebd-a7ff089675b4@nbd.name/

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

On 9/15/23 14:06, 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 mt76_rx_tid.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Felix Fietkau <nbd@nbd.name>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Cc: Ryder Lee <ryder.lee@mediatek.com>
> Cc: Shayne Chen <shayne.chen@mediatek.com>
> Cc: Sean Wang <sean.wang@mediatek.com>
> Cc: Kalle Valo <kvalo@kernel.org>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Cc: linux-wireless@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-mediatek@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   drivers/net/wireless/mediatek/mt76/mt76.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
> index e8757865a3d0..03ef617b1527 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76.h
> +++ b/drivers/net/wireless/mediatek/mt76/mt76.h
> @@ -376,7 +376,7 @@ struct mt76_rx_tid {
>   
>   	u8 started:1, stopped:1, timer_pending:1;
>   
> -	struct sk_buff *reorder_buf[];
> +	struct sk_buff *reorder_buf[] __counted_by(size);
>   };
>   
>   #define MT_TX_CB_DMA_DONE		BIT(0)