netfilter: nft_fwd_netdev: validate family and chain type

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>

diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c
index aba11c2..ddd28de 100644 (file)
--- 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_neigh_netdev_ops = {
        .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_netdev_ops = {
        .eval           = nft_fwd_netdev_eval,
        .init           = nft_fwd_netdev_init,
        .dump           = nft_fwd_netdev_dump,
+       .validate       = nft_fwd_validate,
        .offload        = nft_fwd_netdev_offload,
 };