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

Gustavo A. R. Silva
2025-05-20T22:48:24Z

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 <kees@kernel.org>

Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks!
-Gustavo

> ---
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Simon Horman <horms@kernel.org>
> Cc: Andrew Lunn <andrew+netdev@lunn.ch>
> Cc: Stanislav Fomichev <sdf@fomichev.me>
> Cc: Cosmin Ratiu <cratiu@nvidia.com>
> Cc: Lei Yang <leiyang@redhat.com>
> Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
> Cc: Ido Schimmel <idosch@nvidia.com>
> Cc: <netdev@vger.kernel.org>
> ---
> 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);