[SRU][J][PATCH 0/1] CVE-2022-49234

[Cengiz Can]

https://ubuntu.com/security/CVE-2022-49234

[ Impact ]

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

net: dsa: Avoid cross-chip syncing of VLAN filtering

Changes to VLAN filtering are not applicable to cross-chip notifications.

On a system like this:

.-----.   .-----.   .-----.
| sw1 +---+ sw2 +---+ sw3 |
'-1-2-'   '-1-2-'   '-1-2-'

Before this change, upon sw1p1 leaving a bridge, a call to
dsa_port_vlan_filtering would also be made to sw2p1 and sw3p1.

In this scenario:

.---------.   .-----.   .-----.
|   sw1   +---+ sw2 +---+ sw3 |
'-1-2-3-4-'   '-1-2-'   '-1-2-'

When sw1p4 would leave a bridge, dsa_port_vlan_filtering would be called for
sw2 and sw3 with a non-existing port - leading to array out-of-bounds accesses
and crashes on mv88e6xxx.

[ Fix ]

jammy/linux: backported from 108dc8741c20

[ Test Plan ]

Build and boot tested.

[ Where Problems Could Occur ]

This change only affects the DSA (Distributed Switch Architecture)
subsystem, and in particular multi-chip topologies where two or more
Ethernet switches are daisy-chained, such as boards using mv88e6xxx
switches. A bad fix could regress VLAN filtering behaviour when ports
leave a bridge on those cross-chip setups. Systems without DSA hardware, or
with a single DSA switch, are not affected by this code path.

[ Other Info ]

Kybele flow-v11-21-g0f091652. Reference: 5fdfa656/v1