Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_taprio: Replace direct dequeue call with peek and qdisc_dequeue_peeked
When taprio’s software path peeks a non-work-conserving child qdisc, the child stashes the peeked skb in its gso_skb; taprio_dequeue_from_txq() then takes the packet with a direct child ->dequeue() call, which ignores that stash, orphans the peeked skb and desyncs the child’s qlen/backlog. With a qfq child this re-enters the child on an emptied list and dereferences NULL, panicking the kernel from softirq on ordinary egress.
Take the packet through qdisc_dequeue_peeked(), as sch_red and sch_sfb now do. The helper returns the child’s stashed skb first and is a no-op when there is none, so a work-conserving child is unaffected and the gated path now consumes the skb whose length was charged to the budget.
Details
- Affected product:
- Debian 10 ELS , Debian 11 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.4.0 (+3 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 12 | Planned | — |
| Oracle Linux 9 UEK 7 | Planned | — |