[NET_SCHED]: Use nla_policy for attribute validation in actions

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 6cb5e30..1aff005 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -54,6 +54,10 @@
 	return 0;
 }
 
+static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
+	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
+};
+
 static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
 			   struct tc_action *a, int ovr, int bind)
 {
@@ -68,12 +72,11 @@
 	if (nla == NULL)
 		return -EINVAL;
 
-	err = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, NULL);
+	err = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
 	if (err < 0)
 		return err;
 
-	if (tb[TCA_MIRRED_PARMS] == NULL ||
-	    nla_len(tb[TCA_MIRRED_PARMS]) < sizeof(*parm))
+	if (tb[TCA_MIRRED_PARMS] == NULL)
 		return -EINVAL;
 	parm = nla_data(tb[TCA_MIRRED_PARMS]);