In the Linux kernel, the following vulnerability has been resolved:net_sched: prio: fix a race in prio_tune()Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timerfires at the wrong time.The race is as follows:CPU 0 CPU 1[1]: lock root[2]: qdisc_tree_flush_backlog()[3]: unlock root | | [5]: lock root | [6]: rehash | [7]: qdisc_tree_reduce_backlog() |[4]: qdisc_put()This can be abused to underflow a parent's qlen.Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()should fix the race, because all packets will be purged from the qdiscbefore releasing the lock.
No PoCs from references.
- https://github.com/w4zu/Debian_security