In the Linux kernel, the following vulnerability has been resolved: net/sched: Fix ethx:ingress ...

In the Linux kernel, the following vulnerability has been resolved:

net/sched: Fix ethx:ingress -> ethy:egress -> ethx:ingress mirred loop

When mirred redirects to ingress (from either ingress or egress) the loop state from sched_mirred_dev array dev is lost because of 1) the packet deferral into the backlog and 2) the fact the sched_mirred_dev array is cleared. In such cases, if there was a loop we won't discover it.

Here's a simple test to reproduce: ip a add dev port0 10.10.10.11/24

tc qdisc add dev port0 clsact tc filter add dev port0 egress protocol ip
prio 10 matchall action mirred ingress redirect dev port1

tc qdisc add dev port1 clsact tc filter add dev port1 ingress protocol ip
prio 10 matchall action mirred egress redirect dev port0

ping -c 1 -W0.01 10.10.10.10