8021q: fix a potential memory leak

[ Upstream commit 916c1689a09bc1ca81f2d7a34876f8d35aadd11b ]

skb_cow called in vlan_reorder_header does not free the skb when it failed,
and vlan_reorder_header returns NULL to reset original skb when it is called
in vlan_untag, lead to a memory leak.

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index e860a4f..77d3532 100644 (file)
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -96,8 +96,11 @@ EXPORT_SYMBOL(vlan_dev_vlan_id);
 
 static struct sk_buff *vlan_reorder_header(struct sk_buff *skb)
 {
-       if (skb_cow(skb, skb_headroom(skb)) < 0)
+       if (skb_cow(skb, skb_headroom(skb)) < 0) {
+               kfree_skb(skb);
                return NULL;
+       }
+
        memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
        skb->mac_header += VLAN_HLEN;
        return skb;