netdev - Re: [RFC PATCH net-next 01/16] bridge: Add MAC Authentication Bypass (MAB) support

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Date:   Fri, 28 Oct 2022 09:45:52 +0200
From:   netdev@...io-technology.com
To:     Vladimir Oltean <vladimir.oltean@....com>
Cc:     Ido Schimmel <idosch@...dia.com>, netdev@...r.kernel.org,
        bridge@...ts.linux-foundation.org, davem@...emloft.net,
        kuba@...nel.org, pabeni@...hat.com, edumazet@...gle.com,
        jiri@...dia.com, petrm@...dia.com, ivecera@...hat.com,
        roopa@...dia.com, razor@...ckwall.org, mlxsw@...dia.com
Subject: Re: [RFC PATCH net-next 01/16] bridge: Add MAC Authentication Bypass
 (MAB) support

On 2022-10-28 00:58, Vladimir Oltean wrote:

> I was going to ask if we should bother to add code to prohibit packets
> from being forwarded to an FDB entry that was learned as LOCKED, since
> that FDB entry is more of a "ghost" and not something fully committed?

I think that it is a security flaw if there is any forwarding to 
BR_FDB_LOCKED
entries. I can imagine a host behind a locked port with no credentials,
that gets a BR_FDB_LOCKED entry and has a friend on another non-locked 
port
who can now communicate uni-directional to the host with the 
BR_FDB_LOCKED
entry. It should not be too hard to create a scheme using UDP packets or
other for that.