[Battlemesh] Linksys promises not to block free firmware

David Lang david at lang.hm
Sat May 14 12:31:42 UTC 2016


On Fri, 13 May 2016, Mitar wrote:

>> are you looking for a technical solution to a technical problem? or
>> trying to find a technical solution for a fear?
>
> Oh, I completely agree that it is stupid, but this fact will not get us
> anywhere. We have to create a solution ourselves and start pitching it
> as the solution manufacturers should adopt, and this is it.
>
> I am also not claiming that no firmware ever. But let's make firmware
> where it is at least as hard to disable that detection as it is on
> current locked TP-links: so you need JTAG to bypass it.
>
> So, do we have a solution which protects from disabling that detection
> with hardware tampering of the table?

Unless you lock the firmware down and prevent any router from working properly 
in any country other than the one it's sold to operate in, you cannot prevent a 
router from operating on the wrong frequency.

And given the 'success' of game console lockdowns, even locked down firmware 
doesn't always work.

So trying for a perfect technical solution isn't going to do any good, there 
isn't one.

But the FCC has never required a perfect technical solution to the problem of 
radios operating on the wrong frequency before, and while the (at least 
disavowed) proposed rules are out there, they are also taking on the cable 
companies on the set-top box issue.

So rather than saying "how do we make it impossible", we should instead be 
showing how easily we make legitimate operation possible. And if there are any 
OS projects that don't implement radar detection, we need to find them and fix 
them. If we can show that we fix anything we find, and as a community consider 
anything that doesn't do the radar detection broken.

Don't encourage people who find ways to use things on the wrong channels by 
putting in the wrong country codes.

radar detection itself is fundamentally broken because the AP can't really tell 
if it's a radar or not, it just knows that something that it can't understand is 
transmitting. That something could be another AP out of range.



Since the area that is sensitive is so small, I've proposed creating an 
app/database that let's people anonyomously and automatically report stations 
that are detected on 'odd'/'wrong' frequencies. This would be DFS if you are 
anywhere close to one of the 50 sensitive airports, channels 12-14 in the US, 
and have versions for other countries that detect incorrect channel use there.

Self policing is the only thing that has a chance of working. You cannot detect 
malicious intent in code. You can't detect that a system doesn't have working 
radar detection in code. The only thing you can do is to prevent anyone from 
modifying the code, and at that point you also prevent fixes to the code when it 
has bugs in it that don't properly detect the radar.

David Lang


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