v4 [PATCH 9/9] 8021q: Check return of dev_set_promiscuity/allmulti

[Wang Chen <wangchen@cn.fujitsu.com>]

dev_set_promiscuity/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 all positive increment for promiscuity and allmulti
to get error return.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Acked-by: Patrick McHardy <kaber@trash.net>
---
 net/8021q/vlan_dev.c |   27 +++++++++++++++++++++------
 1 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 5d055c2..083e0c8 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -543,16 +543,31 @@ static int vlan_dev_open(struct net_device *dev)
 	if (compare_ether_addr(dev->dev_addr, real_dev->dev_addr)) {
 		err = dev_unicast_add(real_dev, dev->dev_addr, ETH_ALEN);
 		if (err < 0)
-			return err;
+			goto out;
 	}
-	memcpy(vlan->real_dev_addr, real_dev->dev_addr, ETH_ALEN);
 
-	if (dev->flags & IFF_ALLMULTI)
-		dev_set_allmulti(real_dev, 1);
-	if (dev->flags & IFF_PROMISC)
-		dev_set_promiscuity(real_dev, 1);
+	if (dev->flags & IFF_ALLMULTI) {
+		err = dev_set_allmulti(real_dev, 1);
+		if (err < 0)
+			goto del_unicast;
+	}
+	if (dev->flags & IFF_PROMISC) {
+		err = dev_set_promiscuity(real_dev, 1);
+		if (err < 0)
+			goto clear_allmulti;
+	}
 
+	memcpy(vlan->real_dev_addr, real_dev->dev_addr, ETH_ALEN);
 	return 0;
+
+clear_allmulti:
+	if (dev->flags & IFF_ALLMULTI)
+		dev_set_allmulti(real_dev, -1);
+del_unicast:
+	if (compare_ether_addr(dev->dev_addr, real_dev->dev_addr))
+		dev_unicast_delete(real_dev, dev->dev_addr, ETH_ALEN);
+out:
+	return err;
 }
 
 static int vlan_dev_stop(struct net_device *dev)