macvlan: Check return of dev_set_allmulti

allmulti might overflow.
Commit: "netdevice: Fix promiscuity and allmulti overflow" in net-next makes
dev_set_promiscuity/allmulti return error number if overflow happened.

Here, we check the positive increment for allmulti to get error return.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index c02ceaa4a216..980001c2cf96 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -189,12 +189,20 @@ static int macvlan_open(struct net_device *dev)
 
         err = dev_unicast_add(lowerdev, dev->dev_addr, ETH_ALEN);
         if (err < 0)
-                return err;
-        if (dev->flags & IFF_ALLMULTI)
-                dev_set_allmulti(lowerdev, 1);
+                goto out;
+        if (dev->flags & IFF_ALLMULTI) {
+                err = dev_set_allmulti(lowerdev, 1);
+                if (err < 0)
+                        goto del_unicast;
+        }
 
         hlist_add_head_rcu(&vlan->hlist, &port->vlan_hash[dev->dev_addr[5]]);
         return 0;
+
+del_unicast:
+        dev_unicast_delete(lowerdev, dev->dev_addr, ETH_ALEN);
+out:
+        return err;
 }
 
 static int macvlan_stop(struct net_device *dev)