macsec: fix secy->n_rx_sc accounting

secy->n_rx_sc is supposed to be the number of _active_ rxsc's within a
secy. This is then used by macsec_send_sci to help decide if we should
add the SCI to the header or not.

This logic is currently broken when we create a new RXSC and turn it
off at creation, as create_rx_sc always sets ->active to true (and
immediately uses that to increment n_rx_sc), and only later
macsec_add_rxsc sets rx_sc->active.

Fixes: c09440f7 ("macsec: introduce IEEE 802.1AE driver")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macsec.c

@@ -1413,7 +1413,8 @@ static struct macsec_rx_sc *del_rx_sc(struct macsec_secy *secy, sci_t sci)
 	return NULL;
 }
 
-static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci)
+static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci,
+					 bool active)
 {
 	struct macsec_rx_sc *rx_sc;
 	struct macsec_dev *macsec;
@@ -1437,7 +1438,7 @@ static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci)
 	}
 
 	rx_sc->sci = sci;
-	rx_sc->active = true;
+	rx_sc->active = active;
 	refcount_set(&rx_sc->refcnt, 1);
 
 	secy = &macsec_priv(dev)->secy;
@@ -1876,6 +1877,7 @@ static int macsec_add_rxsc(struct sk_buff *skb, struct genl_info *info)
 	struct macsec_rx_sc *rx_sc;
 	struct nlattr *tb_rxsc[MACSEC_RXSC_ATTR_MAX + 1];
 	struct macsec_secy *secy;
+	bool active = true;
 	int ret;
 
 	if (!attrs[MACSEC_ATTR_IFINDEX])
@@ -1897,15 +1899,15 @@ static int macsec_add_rxsc(struct sk_buff *skb, struct genl_info *info)
 	secy = &macsec_priv(dev)->secy;
 	sci = nla_get_sci(tb_rxsc[MACSEC_RXSC_ATTR_SCI]);
 
-	rx_sc = create_rx_sc(dev, sci);
+	if (tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE])
+		active = nla_get_u8(tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE]);
+
+	rx_sc = create_rx_sc(dev, sci, active);
 	if (IS_ERR(rx_sc)) {
 		rtnl_unlock();
 		return PTR_ERR(rx_sc);
 	}
 
-	if (tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE])
-		rx_sc->active = !!nla_get_u8(tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE]);
-
 	if (macsec_is_offloaded(netdev_priv(dev))) {
 		const struct macsec_ops *ops;
 		struct macsec_context ctx;