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 <pctammela@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index fdb8f429333d26a1380063445ebfc9afad3aef84..383195955b7d21337ae4db67c817dd6fbe3269d0 100644 (file)
--- 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 35963929e117852b731e61eef697474903a1a04f..e43a4549937230c986d23ba4550573da2d9a53c8 100644 (file)
--- 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,