net/sched: sch_qfq: refactor parsing of netlink parameters

jira LE-588
cve-prereq CVE-2023-3611
commit 2536989

Two parameters can be transformed into netlink policies and
validated while parsing the netlink message.

    Reviewed-by: Simon Horman <[email protected]>
    Acked-by: Jamal Hadi Salim <[email protected]>
    Signed-off-by: Pedro Tammela <[email protected]>
    Signed-off-by: David S. Miller <[email protected]>
    (cherry picked from commit 2536989)

Signed-off-by: David Gomez <[email protected]>

Author: dvdgomez

net/sched/sch_qfq.c

@@ -116,6 +116,7 @@
 
 #define QFQ_MTU_SHIFT		16	/* to support TSO/GSO */
 #define QFQ_MIN_LMAX		512	/* see qfq_slot_insert */
+#define QFQ_MAX_LMAX		(1UL << QFQ_MTU_SHIFT)
 
 #define QFQ_MAX_AGG_CLASSES	8 /* max num classes per aggregate allowed */
 
@@ -217,9 +218,14 @@ static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid)
 	return container_of(clc, struct qfq_class, common);
 }
 
+static struct netlink_range_validation lmax_range = {
+	.min = QFQ_MIN_LMAX,
+	.max = QFQ_MAX_LMAX,
+};
+
 static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = {
-	[TCA_QFQ_WEIGHT] = { .type = NLA_U32 },
-	[TCA_QFQ_LMAX] = { .type = NLA_U32 },
+	[TCA_QFQ_WEIGHT] = NLA_POLICY_RANGE(NLA_U32, 1, QFQ_MAX_WEIGHT),
+	[TCA_QFQ_LMAX] = NLA_POLICY_FULL_RANGE(NLA_U32, &lmax_range),
 };
 
 /*
@@ -411,29 +417,20 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 	}
 
 	err = nla_parse_nested_deprecated(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS],
-					  qfq_policy, NULL);
+					  qfq_policy, extack);
 	if (err < 0)
 		return err;
 
-	if (tb[TCA_QFQ_WEIGHT]) {
+	if (tb[TCA_QFQ_WEIGHT])
 		weight = nla_get_u32(tb[TCA_QFQ_WEIGHT]);
-		if (!weight || weight > (1UL << QFQ_MAX_WSHIFT)) {
-			pr_notice("qfq: invalid weight %u\n", weight);
-			return -EINVAL;
-		}
-	} else
+	else
 		weight = 1;
 
 	if (tb[TCA_QFQ_LMAX])
 		lmax = nla_get_u32(tb[TCA_QFQ_LMAX]);
 	else
 		lmax = psched_mtu(qdisc_dev(sch));
 
-	if (lmax < QFQ_MIN_LMAX || lmax > (1UL << QFQ_MTU_SHIFT)) {
-		pr_notice("qfq: invalid max length %u\n", lmax);
-		return -EINVAL;
-	}
-
 	inv_w = ONE_FP / weight;
 	weight = ONE_FP / inv_w;