From c7cfbd115001f94de9e4053657946a383147e803 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Mon, 29 May 2023 12:52:55 -0700 Subject: [PATCH 1/4] net/sched: sch_ingress: Only create under TC_H_INGRESS ingress Qdiscs are only supposed to be created under TC_H_INGRESS. Return -EOPNOTSUPP if 'parent' is not TC_H_INGRESS, similar to mq_init(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+b53a9c0d1ea4ad62da8b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/0000000000006cf87705f79acf1a@google.com/ Tested-by: Pedro Tammela Acked-by: Jamal Hadi Salim Reviewed-by: Jamal Hadi Salim Reviewed-by: Vlad Buslov Signed-off-by: Peilin Ye Signed-off-by: Jakub Kicinski --- net/sched/sch_ingress.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c index 84838128b9c5..f9ef6deb2770 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); @@ -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(); } From 5eeebfe6c493192b10d516abfd72742900f2a162 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Mon, 29 May 2023 12:53:21 -0700 Subject: [PATCH 2/4] net/sched: sch_clsact: Only create under TC_H_CLSACT clsact Qdiscs are only supposed to be created under TC_H_CLSACT (which equals TC_H_INGRESS). Return -EOPNOTSUPP if 'parent' is not TC_H_CLSACT. Fixes: 1f211a1b929c ("net, sched: add clsact qdisc") Tested-by: Pedro Tammela Acked-by: Jamal Hadi Salim Reviewed-by: Jamal Hadi Salim Reviewed-by: Vlad Buslov Signed-off-by: Peilin Ye Signed-off-by: Jakub Kicinski --- net/sched/sch_ingress.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c index f9ef6deb2770..35963929e117 100644 --- a/net/sched/sch_ingress.c +++ b/net/sched/sch_ingress.c @@ -225,6 +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(); @@ -254,6 +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); From f85fa45d4a9408d98c46c8fa45ba2e3b2f4bf219 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Mon, 29 May 2023 12:54:03 -0700 Subject: [PATCH 3/4] net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact) Qdiscs 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 Acked-by: Jamal Hadi Salim Reviewed-by: Jamal Hadi Salim Reviewed-by: Vlad Buslov Signed-off-by: Peilin Ye Signed-off-by: Jakub Kicinski --- 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, From 9de95df5d15baa956c2b70b9e794842e790a8a13 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Mon, 29 May 2023 12:54:26 -0700 Subject: [PATCH 4/4] net/sched: Prohibit regrafting ingress or clsact Qdiscs 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 Acked-by: Jamal Hadi Salim Reviewed-by: Jamal Hadi Salim Reviewed-by: Vlad Buslov Signed-off-by: Peilin Ye Signed-off-by: Jakub Kicinski --- 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 @@ replay: 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");