net: Updates to netif_index_is_vrf

As Eric noted netif_index_is_vrf is not called with rcu_read_lock held,
so wrap the dev_get_by_index_rcu in rcu_read_lock and unlock.

If VRF is not enabled or oif is 0 skip the device lookup. In both cases
index cannot be the VRF master.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d131755516cae2453a3fed911f395bcf1514628b..8a530f93075409eb39aaced077a76550a68b081a 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3822,12 +3822,22 @@ static inline bool netif_is_vrf(const struct net_device *dev)
 
 static inline bool netif_index_is_vrf(struct net *net, int ifindex)
 {
-       struct net_device *dev = dev_get_by_index_rcu(net, ifindex);
        bool rc = false;
 
+#if IS_ENABLED(CONFIG_NET_VRF)
+       struct net_device *dev;
+
+       if (ifindex == 0)
+               return false;
+
+       rcu_read_lock();
+
+       dev = dev_get_by_index_rcu(net, ifindex);
        if (dev)
                rc = netif_is_vrf(dev);
 
+       rcu_read_unlock();
+#endif
        return rc;
 }