[PATCH v3 net 0/6] net/sched: Fixes for sch_ingress and sch_clsact

[PATCH v3 net 0/6] net/sched: Fixes for sch_ingress and sch_clsact

[Peilin Ye]

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/

Hi all,

These are v3 fixes for ingress and clsact Qdiscs.

Change in v3:
  - add in-body From: tags

Changes in v2:
  - for [1-5/6], include tags from Jamal and Pedro
  - for [6/6], as suggested by Vlad, replay the request if the current
    Qdisc has any ongoing (RTNL-unlocked) filter requests, instead of
    returning -EBUSY to the user
  - use Closes: tag as warned by checkpatch

[1,2/6]: ingress and clsact Qdiscs should only be created under ffff:fff1
  [3/6]: Under ffff:fff1, only create ingress and clsact Qdiscs (for now,
         at least)
  [4/6]: After creating ingress and clsact Qdiscs under ffff:fff1, do not
         graft them again to anywhere else (e.g. as the inner Qdisc of a
         TBF Qdisc)
  [5/6]: Prepare for [6/6], do not reuse that for-loop in qdisc_graft()
         for ingress and clsact Qdiscs
  [6/6]: Fix use-after-free [a] in mini_qdisc_pair_swap()

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

Thanks,
Peilin Ye (6):
  net/sched: sch_ingress: Only create under TC_H_INGRESS
  net/sched: sch_clsact: Only create under TC_H_CLSACT
  net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact)
    Qdiscs
  net/sched: Prohibit regrafting ingress or clsact Qdiscs
  net/sched: Refactor qdisc_graft() for ingress and clsact Qdiscs
  net/sched: qdisc_destroy() old ingress and clsact Qdiscs before
    grafting

 include/net/sch_generic.h |  8 ++++++
 net/sched/sch_api.c       | 60 +++++++++++++++++++++++++++++----------
 net/sched/sch_generic.c   | 14 +++++++--
 net/sched/sch_ingress.c   | 10 +++++--
 4 files changed, 72 insertions(+), 20 deletions(-)

-- 
2.20.1

[PATCH v3 net 1/6] net/sched: sch_ingress: Only create under TC_H_INGRESS

[Peilin Ye]

From: Peilin Ye <yepeilin.cs@gmail.com>

From: Peilin Ye <peilin.ye@bytedance.com>

ingress Qdiscs are only supposed to be created under TC_H_INGRESS.
Similar to mq_init(), return -EOPNOTSUPP if 'parent' is not
TC_H_INGRESS.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+b53a9c0d1ea4ad62da8b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/0000000000006cf87705f79acf1a@google.com/
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
---
change in v3:
  - add in-body From: tag

 net/sched/sch_ingress.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index 84838128b9c5..3d71f7a3b4ad 100644
--- a/net/sched/sch_ingress.c
+++ b/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);
-- 
2.20.1

Re: [PATCH v3 net 1/6] net/sched: sch_ingress: Only create under TC_H_INGRESS

[Peilin Ye]

On Mon, May 22, 2023 at 11:19:44PM -0700, Peilin Ye wrote:
> From: Peilin Ye <yepeilin.cs@gmail.com>

Wonderful.

> From: Peilin Ye <peilin.ye@bytedance.com>

Sorry,
Peilin Ye