[PATCH 5.4 126/155] netfilter: nft_fwd_netdev: allow to redirect to ifb via ingress

Greg Kroah-Hartman
2020-03-31T09:17:27Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

commit bcfabee1afd99484b6ba067361b8678e28bbc065 upstream.

Set skb->tc_redirected to 1, otherwise the ifb driver drops the packet.
Set skb->tc_from_ingress to 1 to reinject the packet back to the ingress
path after leaving the ifb egress path.

This patch inconditionally sets on these two skb fields that are
meaningful to the ifb driver. The existing forward action is guaranteed
to run from ingress path.

Fixes: 39e6dea28adc ("netfilter: nf_tables: add forward expression to the netdev family")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/netfilter/nft_fwd_netdev.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -28,6 +28,10 @@ static void nft_fwd_netdev_eval(const st
struct nft_fwd_netdev *priv = nft_expr_priv(expr);
int oif = regs->data[priv->sreg_dev];

+ /* These are used by ifb only. */
+ pkt->skb->tc_redirected = 1;
+ pkt->skb->tc_from_ingress = 1;
+
nf_fwd_netdev_egress(pkt, oif);
regs->verdict.code = NF_STOLEN;
}