From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Mon, 23 Mar 2020 14:27:16 +0100
Subject: netfilter: nft_fwd_netdev: validate family and chain type
Patch-mainline: v5.6
Git-commit: 76a109fac206e158eb3c967af98c178cff738e6a
References: bsc#1176447

Make sure the forward action is only used from ingress.

Fixes: 39e6dea28adc ("netfilter: nf_tables: add forward expression to the netdev family")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/netfilter/nft_fwd_netdev.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -190,6 +190,13 @@ nla_put_failure:
 	return -1;
 }
 
+static int nft_fwd_validate(const struct nft_ctx *ctx,
+			    const struct nft_expr *expr,
+			    const struct nft_data **data)
+{
+	return nft_chain_validate_hooks(ctx->chain, (1 << NF_NETDEV_INGRESS));
+}
+
 static struct nft_expr_type nft_fwd_netdev_type;
 static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = {
 	.type		= &nft_fwd_netdev_type,
@@ -197,6 +204,7 @@ static const struct nft_expr_ops nft_fwd
 	.eval		= nft_fwd_neigh_eval,
 	.init		= nft_fwd_neigh_init,
 	.dump		= nft_fwd_neigh_dump,
+	.validate	= nft_fwd_validate,
 };
 
 static const struct nft_expr_ops nft_fwd_netdev_ops = {
@@ -205,6 +213,7 @@ static const struct nft_expr_ops nft_fwd
 	.eval		= nft_fwd_netdev_eval,
 	.init		= nft_fwd_netdev_init,
 	.dump		= nft_fwd_netdev_dump,
+	.validate	= nft_fwd_validate,
 	.offload	= nft_fwd_netdev_offload,
 };