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Date:   Fri, 6 Oct 2023 13:21:13 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Felix Fietkau <nbd@nbd.name>, Kalle Valo <kvalo@kernel.org>
Cc:     Lorenzo Bianconi <lorenzo@kernel.org>,
        Ryder Lee <ryder.lee@mediatek.com>,
        Shayne Chen <shayne.chen@mediatek.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        linux-wireless@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] wifi: mt76: Annotate struct mt76_rx_tid with __counted_by
Message-ID: <202310061320.8630F7E51@keescook>
References: <20230915200612.never.786-kees@kernel.org>
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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