Re: [Linux-kernel-mentees][PATCH v2] net: usb: rtl8150: prevent set_ethernet_addr from setting uninit address

[Joe Perches]

On Thu, 2020-10-01 at 13:02 +0530, Anant Thazhemadam wrote:
> When get_registers() fails (which happens when usb_control_msg() fails)
> in set_ethernet_addr(), the uninitialized value of node_id gets copied
> as the address.

unrelated trivia:

> diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
[]
> @@ -274,12 +274,17 @@ static int write_mii_word(rtl8150_t * dev, u8 phy, __u8 
> indx, u16 reg)
>               return 1;
>  }
>  
> -static inline void set_ethernet_addr(rtl8150_t * dev)
> +static bool set_ethernet_addr(rtl8150_t *dev)
>  {
>       u8 node_id[6];

This might be better as:

        u8 node_id[ETH_ALEN];

> +     int ret;
>  
> -     get_registers(dev, IDR, sizeof(node_id), node_id);
> -     memcpy(dev->netdev->dev_addr, node_id, sizeof(node_id));
> +     ret = get_registers(dev, IDR, sizeof(node_id), node_id);
> +     if (ret == sizeof(node_id)) {
> +             memcpy(dev->netdev->dev_addr, node_id, sizeof(node_id));

and
                ether_addr_copy(dev->netdev->dev_addr, node_id);