diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index e1b7e05..7422989 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -67,6 +67,14 @@ int nf_register_hook(struct nf_hook_ops *reg)
 	struct nf_hook_ops *elem;
 	int err;
 
+	if (reg->pf >= NFPROTO_NUMPROTO || reg->hooknum >= NF_MAX_HOOKS) {
+		WARN(reg->pf >= NFPROTO_NUMPROTO,
+		     "netfilter: Invalid nfproto %d\n", reg->pf);
+		WARN(reg->hooknum >= NF_MAX_HOOKS,
+		     "netfilter: Invalid hooknum %d\n", reg->hooknum);
+		return -EINVAL;
+	}
+
 	err = mutex_lock_interruptible(&nf_hook_mutex);
 	if (err < 0)
 		return err;