netdev - Re: [PATCH net-next v1 1/1] net: bridge: ensure that link-local traffic cannot unlock a locked port

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Date:   Fri, 1 Jul 2022 09:47:24 +0200
From:   Hans S <schultz.hans@...il.com>
To:     Ido Schimmel <idosch@...dia.com>
Cc:     Hans Schultz <hans@...io-technology.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>, Jiri Pirko <jiri@...nulli.us>,
        Ivan Vecera <ivecera@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Shuah Khan <shuah@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Hans Schultz <schultz.hans+netdev@...il.com>,
        linux-kernel@...r.kernel.org, bridge@...ts.linux-foundation.org,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH net-next v1 1/1] net: bridge: ensure that link-local
 traffic cannot unlock a locked port

One question though... wouldn't it be an issue that the mentioned
option setting is bridge wide, while the patch applies a per-port
effect?

On Thu, Jun 30, 2022 at 1:38 PM Ido Schimmel <idosch@...dia.com> wrote:
>
> On Thu, Jun 30, 2022 at 01:16:34PM +0200, Hans Schultz wrote:
> > This patch is related to the patch set
> > "Add support for locked bridge ports (for 802.1X)"
> > Link: https://lore.kernel.org/netdev/20220223101650.1212814-1-schultz.hans+netdev@gmail.com/
> >
> > This patch makes the locked port feature work with learning turned on,
> > which is enabled with the command:
> >
> > bridge link set dev DEV learning on
> >
> > Without this patch, link local traffic (01:80:c2) like EAPOL packets will
> > create a fdb entry when ingressing on a locked port with learning turned
> > on, thus unintentionally opening up the port for traffic for the said MAC.
> >
> > Some switchcore features like Mac-Auth and refreshing of FDB entries,
> > require learning enables on some switchcores, f.ex. the mv88e6xxx family.
> > Other features may apply too.
> >
> > Since many switchcores trap or mirror various multicast packets to the
> > CPU, link local traffic will unintentionally unlock the port for the
> > SA mac in question unless prevented by this patch.
>
> Why not just teach hostapd to do:
>
> echo 1 > /sys/class/net/br0/bridge/no_linklocal_learn
>
> ?