net: core: Switch netif_set_mac_address() to struct sockaddr_storage

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.

Acked-by: Gustavo A. R. Silva <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: kees

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);

net/core/dev.c

@@ -9669,23 +9669,23 @@ 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;
 	int err;
 
 	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;
 	}

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;

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);