CVE-2023-4128: Fixes in Linux Kernel

A flaw in the Linux Kernel found. Use after free in the net/sched classifiers (clsfw, clsu32 and clsroute) can happen because of mainline/net/sched/clsfw.c incorrect handling of the existing filter in .change method that leads to an extra unbindtcf call for the associated class and that allows that class to be removed while it's still used. These bugs can be used for a local privilege escalation.

Upstream patch: https://lore.kernel.org/netdev/193d6cdf-d6c9-f9be-c36a-b2a7551d5fb6@mojatatu.com/

— Red Hat

A use-after-free flaw was found in net/sched/clsfw.c in classifiers (clsfw, clsu32, and clsroute) in the Linux Kernel. This flaw allows a local attacker to perform a local privilege escalation due to incorrect handling of the existing filter, leading to a kernel information leak issue.

Linux Kernel could allow a local authenticated attacker to gain elevated privileges on the system, caused by a use-after-free flaw in net/sched/clsfw.c in classifiers. By sending a specially crafted request, an authenticated attacker could exploit this vulnerability to gain elevated privileges.

— IBM