netdev - Re: [PATCH] net: ti: icssg-prueth: Check return value to avoid a kernel oops

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Message-ID: <89f81b99-b505-48ad-b717-99e5d4d8e87b@kernel.org>
Date: Sun, 23 Mar 2025 09:19:35 +0200
From: Roger Quadros <rogerq@...nel.org>
To: Benedikt Spranger <b.spranger@...utronix.de>, netdev@...r.kernel.org
Cc: MD Danish Anwar <danishanwar@...com>, Andrew Lunn <andrew+netdev@...n.ch>
Subject: Re: [PATCH] net: ti: icssg-prueth: Check return value to avoid a
 kernel oops

Hi,

Did you actually get a kernel oops? If yes, which part of code produces the oops.

On 22/03/2025 16:33, Benedikt Spranger wrote:
> of_get_ethdev_address() may fail, do not set a MAC address and return

Even if it fails we do set a random MAC address and do not return error.
So above statement is false.


> an error. The icssg-prueth driver ignores that failure and try to validate
> the MAC address. This let to a NULL pointer dereference in this case.
> 
> Check the return value of of_get_ethdev_address() before validating the
> MAC address.

If of_get_ethdev_address() fails the netdev address will remain zero (as it was
zero initialized during allocation) so is_valid_ether_addr() will fail as well.

> 
> Signed-off-by: Benedikt Spranger <b.spranger@...utronix.de>
> ---
>  drivers/net/ethernet/ti/icssg/icssg_prueth.c     | 2 +-
>  drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.c b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> index 9a75733e3f8f..273615c8923c 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.c
> @@ -1152,7 +1152,7 @@ static int prueth_netdev_init(struct prueth *prueth,
>  
>  	/* get mac address from DT and set private and netdev addr */
>  	ret = of_get_ethdev_address(eth_node, ndev);
> -	if (!is_valid_ether_addr(ndev->dev_addr)) {
> +	if (ret || !is_valid_ether_addr(ndev->dev_addr)) {
>  		eth_hw_addr_random(ndev);
>  		dev_warn(prueth->dev, "port %d: using random MAC addr: %pM\n",
>  			 port, ndev->dev_addr);
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c b/drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c
> index 64a19ff39562..61c5e10e7077 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth_sr1.c
> @@ -862,7 +862,7 @@ static int prueth_netdev_init(struct prueth *prueth,
>  
>  	/* get mac address from DT and set private and netdev addr */
>  	ret = of_get_ethdev_address(eth_node, ndev);
> -	if (!is_valid_ether_addr(ndev->dev_addr)) {
> +	if (ret || !is_valid_ether_addr(ndev->dev_addr)) {
>  		eth_hw_addr_random(ndev);
>  		dev_warn(prueth->dev, "port %d: using random MAC addr: %pM\n",
>  			 port, ndev->dev_addr);

-- 
cheers,
-roger