From: Zhengchao Shao Date: Thu, 8 Jun 2023 06:27:56 +0000 (+0800) Subject: net/sched: taprio: fix slab-out-of-bounds Read in taprio_dequeue_from_txq X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=be3618d9651002cd5ff190dbfc6cf78f03e34e27;p=linux.git net/sched: taprio: fix slab-out-of-bounds Read in taprio_dequeue_from_txq As shown in [1], out-of-bounds access occurs in two cases: 1)when the qdisc of the taprio type is used to replace the previously configured taprio, count and offset in tc_to_txq can be set to 0. In this case, the value of *txq in taprio_next_tc_txq() will increases continuously. When the number of accessed queues exceeds the number of queues on the device, out-of-bounds access occurs. 2)When packets are dequeued, taprio can be deleted. In this case, the tc rule of dev is cleared. The count and offset values are also set to 0. In this case, out-of-bounds access is also caused. Now the restriction on the queue number is added. [1] https://groups.google.com/g/syzkaller-bugs/c/_lYOKgkBVMg Fixes: 2f530df76c8c ("net/sched: taprio: give higher priority to higher TCs in software dequeue mode") Reported-by: syzbot+04afcb3d2c840447559a@syzkaller.appspotmail.com Signed-off-by: Zhengchao Shao Tested-by: Pedro Tammela Signed-off-by: David S. Miller --- diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index dd7dea2f6e836..cf0e61ed92253 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -797,6 +797,9 @@ static struct sk_buff *taprio_dequeue_tc_priority(struct Qdisc *sch, taprio_next_tc_txq(dev, tc, &q->cur_txq[tc]); + if (q->cur_txq[tc] >= dev->num_tx_queues) + q->cur_txq[tc] = first_txq; + if (skb) return skb; } while (q->cur_txq[tc] != first_txq);