Re: [PATCH net v2] net: stmmac: Fix incorrect dereference in interrupt handlers

[Serge Semin]

On Wed, Feb 14, 2024 at 12:27:17PM +0300, Pavel Sakharov wrote:
> If 'dev' or 'data' is NULL, the 'priv' variable has an incorrect address
> when dereferencing calling netdev_err().
> 
> Since we get as 'dev_id' or 'data' what was passed as the 'dev' argument
> to request_irq() during interrupt initialization (that is, the net_device
> and rx/tx queue pointers initialized at the time of the call) and since
> there are usually no checks for the 'dev_id' argument in such handlers
> in other drivers, remove these checks from the handlers in stmmac driver.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.

LGTM. Thanks!

Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>

-Serge(y)

> 
> Fixes: 8532f613bc78 ("net: stmmac: introduce MSI Interrupt routines for mac, safety, RX & TX")
> Signed-off-by: Pavel Sakharov <p.sakharov@xxxxxxxxx>
> ---
> v2: Drop the second argument checks in the handlers as suggested by Serge Semin <fancer.lancer@xxxxxxxxx>.
> 
>  .../net/ethernet/stmicro/stmmac/stmmac_main.c | 20 -------------------
>  1 file changed, 20 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 75d029704503..e80d77bd9f1f 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -6059,11 +6059,6 @@ static irqreturn_t stmmac_mac_interrupt(int irq, void *dev_id)
>  	struct net_device *dev = (struct net_device *)dev_id;
>  	struct stmmac_priv *priv = netdev_priv(dev);
>  
> -	if (unlikely(!dev)) {
> -		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
> -		return IRQ_NONE;
> -	}
> -
>  	/* Check if adapter is up */
>  	if (test_bit(STMMAC_DOWN, &priv->state))
>  		return IRQ_HANDLED;
> @@ -6079,11 +6074,6 @@ static irqreturn_t stmmac_safety_interrupt(int irq, void *dev_id)
>  	struct net_device *dev = (struct net_device *)dev_id;
>  	struct stmmac_priv *priv = netdev_priv(dev);
>  
> -	if (unlikely(!dev)) {
> -		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
> -		return IRQ_NONE;
> -	}
> -
>  	/* Check if adapter is up */
>  	if (test_bit(STMMAC_DOWN, &priv->state))
>  		return IRQ_HANDLED;
> @@ -6105,11 +6095,6 @@ static irqreturn_t stmmac_msi_intr_tx(int irq, void *data)
>  	dma_conf = container_of(tx_q, struct stmmac_dma_conf, tx_queue[chan]);
>  	priv = container_of(dma_conf, struct stmmac_priv, dma_conf);
>  
> -	if (unlikely(!data)) {
> -		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
> -		return IRQ_NONE;
> -	}
> -
>  	/* Check if adapter is up */
>  	if (test_bit(STMMAC_DOWN, &priv->state))
>  		return IRQ_HANDLED;
> @@ -6136,11 +6121,6 @@ static irqreturn_t stmmac_msi_intr_rx(int irq, void *data)
>  	dma_conf = container_of(rx_q, struct stmmac_dma_conf, rx_queue[chan]);
>  	priv = container_of(dma_conf, struct stmmac_priv, dma_conf);
>  
> -	if (unlikely(!data)) {
> -		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
> -		return IRQ_NONE;
> -	}
> -
>  	/* Check if adapter is up */
>  	if (test_bit(STMMAC_DOWN, &priv->state))
>  		return IRQ_HANDLED;
> -- 
> 2.43.0
>