[PATCH] net: ethernet: mediatek: add NULL check on of_match_device() return value

Andrew Lunn
2017-07-07T14:57:17Z

On Fri, Jul 07, 2017 at 02:11:35AM -0500, Gustavo A. R. Silva wrote:
> Check return value from call to of_match_device()
> in order to prevent a NULL pointer dereference.
>
> In case of NULL print error message and return -ENODEV
>
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> ---
> drivers/net/ethernet/mediatek/mtk_eth_soc.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index adaaafc..6a77dea 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -2408,6 +2408,11 @@ static int mtk_probe(struct platform_device *pdev)
> int i;
>
> match = of_match_device(of_mtk_match, &pdev->dev);
> + if (!match) {
> + dev_err(&pdev->dev, "failed to match device\n");
> + return -ENODEV;
> + }
> +
> soc = (struct mtk_soc_data *)match->data;

Hi Gustavo

I think you are fixing the wrong thing. The soc variable is unused. Also,

const struct of_device_id of_mtk_match[] = {
{ .compatible = "mediatek,mt2701-eth" },
{},
};

So match->data is NULL. This code is all pointless and should be
removed, rather than try to avoid a NULL pointer dereference which can
not actually happen.

Andrew