CVE-2021-47293

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/sched: act_skbmod: omitir paquetes que no sean Ethernet. Actualmente, tcf_skbmod_act() asume que los paquetes usan Ethernet como protocolo L2, lo cual no siempre es el caso. Como ejemplo, para dispositivos CAN: $ ip link add dev vcan0 type vcan $ ip link set up vcan0 $ tc qdisc add dev vcan0 root handle 1: htb $ tc filter add dev vcan0 parent 1: protocolo ip prio 10 \ matchall action skbmod swap mac Hacer lo anterior corrompe silenciosamente todos los paquetes. No realice acciones de skbmod para paquetes que no sean Ethernet.

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_skbmod: Skip non-Ethernet packets Currently tcf_skbmod_act() assumes that packets use Ethernet as their L2 protocol, which is not always the case. As an example, for CAN devices: $ ip link add dev vcan0 type vcan $ ip link set up vcan0 $ tc qdisc add dev vcan0 root handle 1: htb $ tc filter add dev vcan0 parent 1: protocol ip prio 10 \ matchall action skbmod swap mac Doing the above silently corrupts all the packets. Do not perform skbmod actions for non-Ethernet packets.

An update for kernel is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions, and Red Hat Enterprise Linux 8.6 Telecommunications Update Service. Issues addressed include code execution, null pointer, and use-after-free vulnerabilities.