net: sched: sch_multiq: fix possible OOB write in multiq_tune()
[ Upstream commit affc18fdc694190ca7575b9a86632a73b9fe043d ]
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.
BUG=b/349787386
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-36978 in the Linux kernel.
cos-patch: security-high
Fixes: c2999f7fb05b ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Change-Id: Ia3e5545208c7dfd4fa85c0de6691cfbc35a18007
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/75479
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Arnav Kansal <rnv@google.com>
Reviewed-by: Kevin Berry <kpberry@google.com>
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index 75c9c86..0d6649d 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -185,7 +185,7 @@
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;
