[PATCH] net: ethernet: mtk-star-emac: fix error path in RX handling

[PATCH] net: ethernet: mtk-star-emac: fix error path in RX handling

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

The dma_addr field in desc_data must not be overwritten until after the
new skb is mapped. Currently we do replace it with uninitialized value
in error path. This change fixes it by moving the assignment before the
label to which we jump after mapping or allocation errors.

Fixes: 8c7bd5a454ff ("net: ethernet: mtk-star-emac: new driver")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/net/ethernet/mediatek/mtk_star_emac.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_star_emac.c b/drivers/net/ethernet/mediatek/mtk_star_emac.c
index b74349cede28..72bb624a6a68 100644
--- a/drivers/net/ethernet/mediatek/mtk_star_emac.c
+++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c
@@ -1308,6 +1308,8 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv)
 		goto push_new_skb;
 	}
 
+	desc_data.dma_addr = new_dma_addr;
+
 	/* We can't fail anymore at this point: it's safe to unmap the skb. */
 	mtk_star_dma_unmap_rx(priv, &desc_data);
 
@@ -1318,7 +1320,6 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv)
 	netif_receive_skb(desc_data.skb);
 
 push_new_skb:
-	desc_data.dma_addr = new_dma_addr;
 	desc_data.len = skb_tailroom(new_skb);
 	desc_data.skb = new_skb;
 
-- 
2.25.0


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Re: [PATCH] net: ethernet: mtk-star-emac: fix error path in RX handling

[Nathan Chancellor]

On Wed, May 27, 2020 at 11:24:04AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> The dma_addr field in desc_data must not be overwritten until after the
> new skb is mapped. Currently we do replace it with uninitialized value
> in error path. This change fixes it by moving the assignment before the
> label to which we jump after mapping or allocation errors.
> 
> Fixes: 8c7bd5a454ff ("net: ethernet: mtk-star-emac: new driver")
> Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build

> ---
>  drivers/net/ethernet/mediatek/mtk_star_emac.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mediatek/mtk_star_emac.c b/drivers/net/ethernet/mediatek/mtk_star_emac.c
> index b74349cede28..72bb624a6a68 100644
> --- a/drivers/net/ethernet/mediatek/mtk_star_emac.c
> +++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c
> @@ -1308,6 +1308,8 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv)
>  		goto push_new_skb;
>  	}
>  
> +	desc_data.dma_addr = new_dma_addr;
> +
>  	/* We can't fail anymore at this point: it's safe to unmap the skb. */
>  	mtk_star_dma_unmap_rx(priv, &desc_data);
>  
> @@ -1318,7 +1320,6 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv)
>  	netif_receive_skb(desc_data.skb);
>  
>  push_new_skb:
> -	desc_data.dma_addr = new_dma_addr;
>  	desc_data.len = skb_tailroom(new_skb);
>  	desc_data.skb = new_skb;
>  
> -- 
> 2.25.0
> 

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Re: [PATCH] net: ethernet: mtk-star-emac: fix error path in RX handling

[David Miller]

From: Bartosz Golaszewski <brgl@bgdev.pl>
Date: Wed, 27 May 2020 11:24:04 +0200

> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> The dma_addr field in desc_data must not be overwritten until after the
> new skb is mapped. Currently we do replace it with uninitialized value
> in error path. This change fixes it by moving the assignment before the
> label to which we jump after mapping or allocation errors.
> 
> Fixes: 8c7bd5a454ff ("net: ethernet: mtk-star-emac: new driver")
> Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Applied, please use "[PATCH net-next]" to clearly indicate the target
GIT tree next time.

Thank you.

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