In the Linux kernel, the following vulnerability has been resolved:
macvlan: enforce a consistent minimal mtu
macvlan should enforce a minimal mtu of 68, even at link creation.
This patch avoids the current behavior (which could lead to crashes in ipv6 stack if the link is brought up)
$ ip link add macvlan1 link eno1 mtu 8 type macvlan # This should fail ! $ ip link sh dev macvlan1 5: macvlan1@eno1: <BROADCAST,MULTICAST> mtu 8 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 02:47:6c:24:74:82 brd ff:ff:ff:ff:ff:ff $ ip link set macvlan1 mtu 67 Error: mtu less than device minimum. $ ip link set macvlan1 mtu 68 $ ip link set macvlan1 mtu 8 Error: mtu less than device minimum.
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | 4.10 | 4.14.300 |
| linux / linux_kernel | 4.15 | 4.19.267 |
| linux / linux_kernel | 4.20 | 5.4.225 |
| linux / linux_kernel | 5.5 | 5.10.156 |
| linux / linux_kernel | 5.11 | 5.15.80 |
| linux / linux_kernel | 5.16 | 6.0.10 |