net: sched: sch_multiq: fix possible OOB write in multiq_tune()

q->bands will be assigned to qopt->bands to execute subsequent code logic
after kmalloc. So the old q->bands should not be used in kmalloc.
Otherwise, an out-of-bounds write will occur.

Fixes: c2999f7fb0 ("net: sched: multiq: don't call qdisc_put() while holding tree lock")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Hangyu Hua 2024-06-03 15:13:03 +08:00 committed by David S. Miller
parent 491aee894a
commit affc18fdc6

View File

@ -185,7 +185,7 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt,
qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
removed = kmalloc(sizeof(*removed) * (q->max_bands - q->bands),
removed = kmalloc(sizeof(*removed) * (q->max_bands - qopt->bands),
GFP_KERNEL);
if (!removed)
return -ENOMEM;