Re: [PATCH 2/7] net: core: Switch netif_set_mac_address() to struct sockaddr_storage

On 20/05/25 16:31, Kees Cook wrote:
> In order to avoid passing around struct sockaddr that has a size the
> compiler cannot reason about (nor track at runtime), convert
> netif_set_mac_address() to take struct sockaddr_storage. This is just a
> cast conversion, so there is are no binary changes. Following patches
> will make actual allocation changes.
> 
> Signed-off-by: Kees Cook <[email protected]>

Acked-by: Gustavo A. R. Silva <[email protected]>

Thanks!
-Gustavo

> ---
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: Simon Horman <[email protected]>
> Cc: Andrew Lunn <[email protected]>
> Cc: Stanislav Fomichev <[email protected]>
> Cc: Cosmin Ratiu <[email protected]>
> Cc: Lei Yang <[email protected]>
> Cc: Kuniyuki Iwashima <[email protected]>
> Cc: Ido Schimmel <[email protected]>
> Cc: <[email protected]>
> ---
>   include/linux/netdevice.h |  2 +-
>   net/core/dev.c            | 10 +++++-----
>   net/core/dev_api.c        |  4 ++--
>   net/core/rtnetlink.c      |  2 +-
>   4 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index ea9d335de130..47200a394a02 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -4212,7 +4212,7 @@ int netif_set_mtu(struct net_device *dev, int new_mtu);
>   int dev_set_mtu(struct net_device *, int);
>   int dev_pre_changeaddr_notify(struct net_device *dev, const char *addr,
>   			      struct netlink_ext_ack *extack);
> -int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa,
> +int netif_set_mac_address(struct net_device *dev, struct sockaddr_storage *ss,
>   			  struct netlink_ext_ack *extack);
>   int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa,
>   			struct netlink_ext_ack *extack);
> diff --git a/net/core/dev.c b/net/core/dev.c
> index fccf2167b235..f8c8aad7df2e 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -9655,7 +9655,7 @@ int dev_pre_changeaddr_notify(struct net_device *dev, const char *addr,
>   }
>   EXPORT_SYMBOL(dev_pre_changeaddr_notify);
>   
> -int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa,
> +int netif_set_mac_address(struct net_device *dev, struct sockaddr_storage *ss,
>   			  struct netlink_ext_ack *extack)
>   {
>   	const struct net_device_ops *ops = dev->netdev_ops;
> @@ -9663,15 +9663,15 @@ int netif_set_mac_address(struct net_device *dev, struct sockaddr *sa,
>   
>   	if (!ops->ndo_set_mac_address)
>   		return -EOPNOTSUPP;
> -	if (sa->sa_family != dev->type)
> +	if (ss->ss_family != dev->type)
>   		return -EINVAL;
>   	if (!netif_device_present(dev))
>   		return -ENODEV;
> -	err = dev_pre_changeaddr_notify(dev, sa->sa_data, extack);
> +	err = dev_pre_changeaddr_notify(dev, ss->__data, extack);
>   	if (err)
>   		return err;
> -	if (memcmp(dev->dev_addr, sa->sa_data, dev->addr_len)) {
> -		err = ops->ndo_set_mac_address(dev, sa);
> +	if (memcmp(dev->dev_addr, ss->__data, dev->addr_len)) {
> +		err = ops->ndo_set_mac_address(dev, ss);
>   		if (err)
>   			return err;
>   	}
> diff --git a/net/core/dev_api.c b/net/core/dev_api.c
> index f9a160ab596f..b5f293e637d9 100644
> --- a/net/core/dev_api.c
> +++ b/net/core/dev_api.c
> @@ -91,7 +91,7 @@ int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa,
>   
>   	down_write(&dev_addr_sem);
>   	netdev_lock_ops(dev);
> -	ret = netif_set_mac_address(dev, sa, extack);
> +	ret = netif_set_mac_address(dev, (struct sockaddr_storage *)sa, extack);
>   	netdev_unlock_ops(dev);
>   	up_write(&dev_addr_sem);
>   
> @@ -332,7 +332,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa,
>   	int ret;
>   
>   	netdev_lock_ops(dev);
> -	ret = netif_set_mac_address(dev, sa, extack);
> +	ret = netif_set_mac_address(dev, (struct sockaddr_storage *)sa, extack);
>   	netdev_unlock_ops(dev);
>   
>   	return ret;
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 8a914b37ef6e..9743f1c2ae3c 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -3100,7 +3100,7 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev,
>   
>   		memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]),
>   		       dev->addr_len);
> -		err = netif_set_mac_address(dev, sa, extack);
> +		err = netif_set_mac_address(dev, (struct sockaddr_storage *)sa, extack);
>   		kfree(sa);
>   		if (err) {
>   			up_write(&dev_addr_sem);