netfilter: nft_flow_offload: missing netlink attribute policy

The netlink attribute policy for NFTA_FLOW_TABLE_NAME is missing.

Fixes: a3c90f7a ("netfilter: nf_tables: flow offload expression")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_flow_offload.c

@@ -149,6 +149,11 @@ static int nft_flow_offload_validate(const struct nft_ctx *ctx,
 	return nft_chain_validate_hooks(ctx->chain, hook_mask);
 }
 
+static const struct nla_policy nft_flow_offload_policy[NFTA_FLOW_MAX + 1] = {
+	[NFTA_FLOW_TABLE_NAME]	= { .type = NLA_STRING,
+				    .len = NFT_NAME_MAXLEN - 1 },
+};
+
 static int nft_flow_offload_init(const struct nft_ctx *ctx,
 				 const struct nft_expr *expr,
 				 const struct nlattr * const tb[])
@@ -207,6 +212,7 @@ static const struct nft_expr_ops nft_flow_offload_ops = {
 static struct nft_expr_type nft_flow_offload_type __read_mostly = {
 	.name		= "flow_offload",
 	.ops		= &nft_flow_offload_ops,
+	.policy		= nft_flow_offload_policy,
 	.maxattr	= NFTA_FLOW_MAX,
 	.owner		= THIS_MODULE,
 };