skbuff: Fix offset error in skb_reorder_vlan_header

commit f654861569872d10dcb79d9d7ca219b316f94ff0 upstream.

skb_reorder_vlan_header is called after the vlan header has
been pulled.  As a result the offset of the begining of
the mac header has been incrased by 4 bytes (VLAN_HLEN).
When moving the mac addresses, include this incrase in
the offset calcualation so that the mac addresses are
copied correctly.

Fixes: a6e18ff1117 (vlan: Fix untag operations of stacked vlans with REORDER_HEADER off)
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: Vladislav Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d50deee76502a69d925f2153a4ca6e1053560ef4..7e31a99e0ed91655d2d1a7a5004ea5ad0522c139 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3996,7 +3996,7 @@ static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
                return NULL;
        }
 
-       memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len,
+       memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len - VLAN_HLEN,
                2 * ETH_ALEN);
        skb->mac_header += VLAN_HLEN;
        return skb;