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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Johannes Berg <johannes@sipsolutions.net>,
        Karthikeyan Periyasamy <periyasa@codeaurora.org>
Cc:     linux-wireless@vger.kernel.org
Subject: Re: [PATCH] mac80211: reject zero MAC address in add station
In-Reply-To: <218afd33eda4410472c2a99624f81908cf535cb4.camel@sipsolutions.net>
References: <1563959770-21570-1-git-send-email-periyasa@codeaurora.org> <0cc7d0c578b60730e77ecd03e2df240dd1b393a0.camel@sipsolutions.net> <fd6e7a7e0746b861bbbd660bf54cc675@codeaurora.org> <218afd33eda4410472c2a99624f81908cf535cb4.camel@sipsolutions.net>
Date:   Fri, 26 Jul 2019 16:23:04 +0200
Message-ID: <87imroyiwn.fsf@toke.dk>
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Johannes Berg <johannes@sipsolutions.net> writes:

> On Fri, 2019-07-26 at 19:36 +0530, Karthikeyan Periyasamy wrote:
>> > > Don't allow using a zero MAC address as the station
>> > > MAC address. so validated the MAC address using
>> > > is_valid_ether_addr.
>> > 
>> > Theoretically, all zeroes might have been a valid address at some 
>> > point.
>> > I see no reason not to reject it, but I'd like to know why you ended up
>> > with this now??
>> > 
>> 
>> Its a Wireless fuzz testing tool (codenomicon) which sends out different 
>> types of frames to the AP. It actually tampers legitimate wireless 
>> frames (Probe, Auth, Assoc, Data etc..) and will send to the AP. I 
>> thought allowing a zero MAC address station is not a valid. so validated 
>> the given MAC address. Just for curious, which case all zero address is 
>> a valid MAC.
>
> Well, it isn't really, but the OUI 00:00:00 *is* in fact assigned (or
> was), and theoretically the vendor could assign it to a device.

Heh, now that we allow routing the 0.0.0.0/8 subnet, this means that the
following could be a perfectly sensible thing to do:

'ip neigh add 0.0.0.1/8 lladdr 00:00:00:00:00:01 dev wlan0'

One bit per address per network layer ought to be enough for everyone,
right? ;)

-Toke