CVE-2021-47293
Description
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.
How to fix
- linux linux_kernel4.19.199, 5.4.136, 5.10.54, 5.13.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 4.9 ≤ v < 4.19.199, 4.20 ≤ v < 5.4.136, 5.5 ≤ v < 5.10.54, 5.11 ≤ v < 5.13.6, 5.14 | 4.19.199, 5.4.136, 5.10.54, 5.13.6 |
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