netfilter: nft_fwd_netdev: validate family and chain type

commit 76a109fac206e158eb3c967af98c178cff738e6a upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c
index ce13a50b91893fd67a9c8586f7cca53278b1067d..ee190fa4dc34700db740fc81a070ea1ea309c40c 100644 (file)
--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -62,6 +62,13 @@ 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_netdev_ops = {
        .type           = &nft_fwd_netdev_type,
@@ -69,6 +76,7 @@ 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,
 };
 
 static struct nft_expr_type nft_fwd_netdev_type __read_mostly = {