Merge branch 'net-sched-fixes-for-sch_ingress-and-sch_clsact'

Peilin Ye says:

====================
net/sched: Fixes for sch_ingress and sch_clsact

These are v6 fixes for ingress and clsact Qdiscs, including only first 4
patches (already tested and reviewed) from v5.  Patch 5 and 6 from
previous versions are still under discussion and will be sent separately.

[a] https://syzkaller.appspot.com/bug?extid=b53a9c0d1ea4ad62da8b

Link to v5: https://lore.kernel.org/r/cover.1684887977.git.peilin.ye@bytedance.com/
Link to v4: https://lore.kernel.org/r/cover.1684825171.git.peilin.ye@bytedance.com/
Link to v3 (incomplete): https://lore.kernel.org/r/cover.1684821877.git.peilin.ye@bytedance.com/
Link to v2: https://lore.kernel.org/r/cover.1684796705.git.peilin.ye@bytedance.com/
Link to v1: https://lore.kernel.org/r/cover.1683326865.git.peilin.ye@bytedance.com/
====================

Link: https://lore.kernel.org/r/cover.1685388545.git.peilin.ye@bytedance.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/sched/sch_api.c

@@ -1252,7 +1252,12 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
 	sch->parent = parent;
 
 	if (handle == TC_H_INGRESS) {
-		sch->flags |= TCQ_F_INGRESS;
+		if (!(sch->flags & TCQ_F_INGRESS)) {
+			NL_SET_ERR_MSG(extack,
+				       "Specified parent ID is reserved for ingress and clsact Qdiscs");
+			err = -EINVAL;
+			goto err_out3;
+		}
 		handle = TC_H_MAKE(TC_H_INGRESS, 0);
 	} else {
 		if (handle == 0) {
@@ -1591,6 +1596,11 @@ static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
 					NL_SET_ERR_MSG(extack, "Invalid qdisc name");
 					return -EINVAL;
 				}
+				if (q->flags & TCQ_F_INGRESS) {
+					NL_SET_ERR_MSG(extack,
+						       "Cannot regraft ingress or clsact Qdiscs");
+					return -EINVAL;
+				}
 				if (q == p ||
 				    (p && check_loop(q, p, 0))) {
 					NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");

net/sched/sch_ingress.c

@@ -80,6 +80,9 @@ static int ingress_init(struct Qdisc *sch, struct nlattr *opt,
 	struct net_device *dev = qdisc_dev(sch);
 	int err;
 
+	if (sch->parent != TC_H_INGRESS)
+		return -EOPNOTSUPP;
+
 	net_inc_ingress_queue();
 
 	mini_qdisc_pair_init(&q->miniqp, sch, &dev->miniq_ingress);
@@ -101,6 +104,9 @@ static void ingress_destroy(struct Qdisc *sch)
 {
 	struct ingress_sched_data *q = qdisc_priv(sch);
 
+	if (sch->parent != TC_H_INGRESS)
+		return;
+
 	tcf_block_put_ext(q->block, sch, &q->block_info);
 	net_dec_ingress_queue();
 }
@@ -134,7 +140,7 @@ static struct Qdisc_ops ingress_qdisc_ops __read_mostly = {
 	.cl_ops			=	&ingress_class_ops,
 	.id			=	"ingress",
 	.priv_size		=	sizeof(struct ingress_sched_data),
-	.static_flags		=	TCQ_F_CPUSTATS,
+	.static_flags		=	TCQ_F_INGRESS | TCQ_F_CPUSTATS,
 	.init			=	ingress_init,
 	.destroy		=	ingress_destroy,
 	.dump			=	ingress_dump,
@@ -219,6 +225,9 @@ static int clsact_init(struct Qdisc *sch, struct nlattr *opt,
 	struct net_device *dev = qdisc_dev(sch);
 	int err;
 
+	if (sch->parent != TC_H_CLSACT)
+		return -EOPNOTSUPP;
+
 	net_inc_ingress_queue();
 	net_inc_egress_queue();
 
@@ -248,6 +257,9 @@ static void clsact_destroy(struct Qdisc *sch)
 {
 	struct clsact_sched_data *q = qdisc_priv(sch);
 
+	if (sch->parent != TC_H_CLSACT)
+		return;
+
 	tcf_block_put_ext(q->egress_block, sch, &q->egress_block_info);
 	tcf_block_put_ext(q->ingress_block, sch, &q->ingress_block_info);
 
@@ -269,7 +281,7 @@ static struct Qdisc_ops clsact_qdisc_ops __read_mostly = {
 	.cl_ops			=	&clsact_class_ops,
 	.id			=	"clsact",
 	.priv_size		=	sizeof(struct clsact_sched_data),
-	.static_flags		=	TCQ_F_CPUSTATS,
+	.static_flags		=	TCQ_F_INGRESS | TCQ_F_CPUSTATS,
 	.init			=	clsact_init,
 	.destroy		=	clsact_destroy,
 	.dump			=	ingress_dump,