2023-05-29 20:07:01

by Peilin Ye

[permalink] [raw]
Subject: [PATCH v6 net 0/4] net/sched: Fixes for sch_ingress and sch_clsact

Link to v5: https://lore.kernel.org/r/[email protected]/
Link to v4: https://lore.kernel.org/r/[email protected]/
Link to v3 (incomplete): https://lore.kernel.org/r/[email protected]/
Link to v2: https://lore.kernel.org/r/[email protected]/
Link to v1: https://lore.kernel.org/r/[email protected]/

Hi all,

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.
Per-patch changelog omitted.

Change in v6:
- only include first 4 patches from previous versions

Changes in v5:
- for [6/6], reinitialize @q, @p (suggested by Vlad) and @tcm after the
"replay:" tag
- for [1,2/6], do nothing in ->destroy() if ->parent isn't ffff:fff1, as
reported by Pedro

Change in v3, v4:
- 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 (4):
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/sch_api.c | 12 +++++++++++-
net/sched/sch_ingress.c | 16 ++++++++++++++--
2 files changed, 25 insertions(+), 3 deletions(-)

--
2.20.1



2023-05-29 20:08:20

by Peilin Ye

[permalink] [raw]
Subject: [PATCH v6 net 4/4] net/sched: Prohibit regrafting ingress or clsact Qdiscs

From: Peilin Ye <[email protected]>

Currently, after creating an ingress (or clsact) Qdisc and grafting it
under TC_H_INGRESS (TC_H_CLSACT), it is possible to graft it again under
e.g. a TBF Qdisc:

$ ip link add ifb0 type ifb
$ tc qdisc add dev ifb0 handle 1: root tbf rate 20kbit buffer 1600 limit 3000
$ tc qdisc add dev ifb0 clsact
$ tc qdisc link dev ifb0 handle ffff: parent 1:1
$ tc qdisc show dev ifb0
qdisc tbf 1: root refcnt 2 rate 20Kbit burst 1600b lat 560.0ms
qdisc clsact ffff: parent ffff:fff1 refcnt 2
^^^^^^^^

clsact's refcount has increased: it is now grafted under both
TC_H_CLSACT and 1:1.

ingress and clsact Qdiscs should only be used under TC_H_INGRESS
(TC_H_CLSACT). Prohibit regrafting them.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 1f211a1b929c ("net, sched: add clsact qdisc")
Tested-by: Pedro Tammela <[email protected]>
Acked-by: Jamal Hadi Salim <[email protected]>
Reviewed-by: Jamal Hadi Salim <[email protected]>
Reviewed-by: Vlad Buslov <[email protected]>
Signed-off-by: Peilin Ye <[email protected]>
---
net/sched/sch_api.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 383195955b7d..49b9c1bbfdd9 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1596,6 +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");
--
2.20.1


2023-05-29 20:22:24

by Peilin Ye

[permalink] [raw]
Subject: [PATCH v6 net 3/4] net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact) Qdiscs

From: Peilin Ye <[email protected]>

Currently it is possible to add e.g. an HTB Qdisc under ffff:fff1
(TC_H_INGRESS, TC_H_CLSACT):

$ ip link add name ifb0 type ifb
$ tc qdisc add dev ifb0 parent ffff:fff1 htb
$ tc qdisc add dev ifb0 clsact
Error: Exclusivity flag on, cannot modify.
$ drgn
...
>>> ifb0 = netdev_get_by_name(prog, "ifb0")
>>> qdisc = ifb0.ingress_queue.qdisc_sleeping
>>> print(qdisc.ops.id.string_().decode())
htb
>>> qdisc.flags.value_() # TCQ_F_INGRESS
2

Only allow ingress and clsact Qdiscs under ffff:fff1. Return -EINVAL
for everything else. Make TCQ_F_INGRESS a static flag of ingress and
clsact Qdiscs.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 1f211a1b929c ("net, sched: add clsact qdisc")
Tested-by: Pedro Tammela <[email protected]>
Acked-by: Jamal Hadi Salim <[email protected]>
Reviewed-by: Jamal Hadi Salim <[email protected]>
Reviewed-by: Vlad Buslov <[email protected]>
Signed-off-by: Peilin Ye <[email protected]>
---
net/sched/sch_api.c | 7 ++++++-
net/sched/sch_ingress.c | 4 ++--
2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index fdb8f429333d..383195955b7d 100644
--- a/net/sched/sch_api.c
+++ b/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) {
diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index 35963929e117..e43a45499372 100644
--- a/net/sched/sch_ingress.c
+++ b/net/sched/sch_ingress.c
@@ -140,7 +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,
@@ -281,7 +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,
--
2.20.1


2023-05-31 07:00:28

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH v6 net 0/4] net/sched: Fixes for sch_ingress and sch_clsact

Hello:

This series was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:

On Mon, 29 May 2023 12:52:31 -0700 you wrote:
> Link to v5: https://lore.kernel.org/r/[email protected]/
> Link to v4: https://lore.kernel.org/r/[email protected]/
> Link to v3 (incomplete): https://lore.kernel.org/r/[email protected]/
> Link to v2: https://lore.kernel.org/r/[email protected]/
> Link to v1: https://lore.kernel.org/r/[email protected]/
>
> Hi all,
>
> [...]

Here is the summary with links:
- [v6,net,1/4] net/sched: sch_ingress: Only create under TC_H_INGRESS
https://git.kernel.org/netdev/net/c/c7cfbd115001
- [v6,net,2/4] net/sched: sch_clsact: Only create under TC_H_CLSACT
https://git.kernel.org/netdev/net/c/5eeebfe6c493
- [v6,net,3/4] net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact) Qdiscs
https://git.kernel.org/netdev/net/c/f85fa45d4a94
- [v6,net,4/4] net/sched: Prohibit regrafting ingress or clsact Qdiscs
https://git.kernel.org/netdev/net/c/9de95df5d15b

You are awesome, thank you!
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