On Mon, 2020-10-12 at 15:02 -0400, Sasha Levin wrote:
> From: Anant Thazhemadam <anant.thazhema...@gmail.com>
> 
> [ Upstream commit f45a4248ea4cc13ed50618ff066849f9587226b2 ]
> 
> When get_registers() fails in set_ethernet_addr(),the uninitialized
> value of node_id gets copied over as the address.
> So, check the return value of get_registers().
> 
> If get_registers() executed successfully (i.e., it returns
> sizeof(node_id)), copy over the MAC address using ether_addr_copy()
> (instead of using memcpy()).
> 
> Else, if get_registers() failed instead, a randomly generated MAC
> address is set as the MAC address instead.

This autosel is premature.

This patch always sets a random MAC.
See the follow on patch: https://lkml.org/lkml/2020/10/11/131
To my knowledge, this follow-ob has yet to be applied:

> diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
[]
> @@ -274,12 +274,20 @@ 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 void set_ethernet_addr(rtl8150_t *dev)
>  {
> -     u8 node_id[6];
> +     u8 node_id[ETH_ALEN];
> +     int ret;
> +
> +     ret = get_registers(dev, IDR, sizeof(node_id), node_id);
>  
> -     get_registers(dev, IDR, sizeof(node_id), node_id);
> -     memcpy(dev->netdev->dev_addr, node_id, sizeof(node_id));
> +     if (ret == sizeof(node_id)) {

So this needs to use
        if (!ret) {

or 
        if (ret < 0)

and reversed code blocks

> +             ether_addr_copy(dev->netdev->dev_addr, node_id);
> +     } else {
> +             eth_hw_addr_random(dev->netdev);
> +             netdev_notice(dev->netdev, "Assigned a random MAC address: 
> %pM\n",
> +                           dev->netdev->dev_addr);
> +     }
>  }
>  
>  static int rtl8150_set_mac_address(struct net_device *netdev, void *p)

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