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Subject: Re: [PATCH][next] dmaengine: stm32-mdma: Use struct_size() helper in
 devm_kzalloc()
To:     "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Vinod Koul <vkoul@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>
CC:     <dmaengine@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linux-hardening@vger.kernel.org>
References: <20210929222922.GA357509@embeddedor>
From:   Amelie DELAUNAY <amelie.delaunay@foss.st.com>
Message-ID: <2e2fdc65-da02-90f3-e870-d63b43593c10@foss.st.com>
Date:   Fri, 1 Oct 2021 09:14:58 +0200
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On 9/30/21 12:29 AM, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worse scenario, could lead to heap overflows.
> 
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>

> ---
>   drivers/dma/stm32-mdma.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
> index 18cbd1e43c2e..d30a4a28d3bf 100644
> --- a/drivers/dma/stm32-mdma.c
> +++ b/drivers/dma/stm32-mdma.c
> @@ -1566,7 +1566,8 @@ static int stm32_mdma_probe(struct platform_device *pdev)
>   	if (count < 0)
>   		count = 0;
>   
> -	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev) + sizeof(u32) * count,
> +	dmadev = devm_kzalloc(&pdev->dev,
> +			      struct_size(dmadev, ahb_addr_masks, count),
>   			      GFP_KERNEL);
>   	if (!dmadev)
>   		return -ENOMEM;
>