diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2025-03-06 15:23:54 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-12 12:51:58 -0700 |
| commit | 0c3057a5a04d07120b3d0ec9c79568fceb9c921e (patch) | |
| tree | 182186645ee082560be958b0a097d35855fadde3 | |
| parent | 081b575617e6f9355edf054cb907bdb8af7ed149 (diff) | |
net_sched: Prevent creation of classes with TC_H_ROOT
The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination
condition when traversing up the qdisc tree to update parent backlog
counters. However, if a class is created with classid TC_H_ROOT, the
traversal terminates prematurely at this class instead of reaching the
actual root qdisc, causing parent statistics to be incorrectly maintained.
In case of DRR, this could lead to a crash as reported by Mingi Cho.
Prevent the creation of any Qdisc class with classid TC_H_ROOT
(0xFFFFFFFF) across all qdisc types, as suggested by Jamal.
Reported-by: Mingi Cho <mincho@theori.io>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Fixes: 066a3b5b2346 ("[NET_SCHED] sch_api: fix qdisc_tree_decrease_qlen() loop")
Link: https://patch.msgid.link/20250306232355.93864-2-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/sched/sch_api.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index e3e91cf867eb..6c625dcd0651 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -2254,6 +2254,12 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n, return -EOPNOTSUPP; } + /* Prevent creation of traffic classes with classid TC_H_ROOT */ + if (clid == TC_H_ROOT) { + NL_SET_ERR_MSG(extack, "Cannot create traffic class with classid TC_H_ROOT"); + return -EINVAL; + } + new_cl = cl; err = -EOPNOTSUPP; if (cops->change) |