netfilter: nft_payload: rebuild vlan header when needed

[ Upstream commit de6843be3082d416eaf2a00b72dad95c784ca980 ]

Skip rebuilding the vlan header when accessing destination and source
mac address.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: 33c563ebf8d3 ("netfilter: nft_payload: skbuff vlan metadata mangle support")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index e5f0d33a27e61afc0d80920d291d002999d08d9f..b1745304dbd22bd33b4c0014e33f5cffe04b74e0 100644 (file)
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -127,7 +127,8 @@ void nft_payload_eval(const struct nft_expr *expr,
                if (!skb_mac_header_was_set(skb) || skb_mac_header_len(skb) == 0)
                        goto err;
 
-               if (skb_vlan_tag_present(skb)) {
+               if (skb_vlan_tag_present(skb) &&
+                   priv->offset >= offsetof(struct ethhdr, h_proto)) {
                        if (!nft_payload_copy_vlan(dest, skb,
                                                   priv->offset, priv->len))
                                goto err;