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/

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/

A use-after-free vulnerability in the Linux kernel's net/sched: clsu32 component can be exploited to achieve local privilege escalation.

When u32change() is called on an existing filter, the whole tcfresult struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcfunbindfilter() is always called on the old instance in the success path, decreasing filtercnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.

We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.