[Cerowrt-devel] New FCC requirements and CeroWrt

David Lang david at lang.hm
Tue Dec 9 16:01:05 EST 2014

The top of the page says:

his page will compile all relevant information available on the FCC's new 
regulations on 5Ghz Wifi and the OpenWrt's community recommendations for 
hardware manufacturers.

Then down below it lists suggested workarounds. Even though that section says 
they aren't recommendations, it still reads like it.

In Linux/OpenWRT there are several layers to deal with.

The radio itself has it's own processor, which runs some hard-coded software and 
(potentially) some additional firmware that is loaded from the OS (with 
validation and cooperation of the hard-coded software)

The Device Driver talks to the radio processor and can ask it to change channels 
or change country codes (if the radio processor knows about those codes)

The software in the OS asks the device driver to ask the radio to change 

Manufacturers can put the checking into whatever layer they want. From a 
openwrt point of view, the more that can be changed by openwrt the better.

There is a key word to recognize, the devices need to be "resistant" to 
inappropriate changes. This doesn't mean that they need to be proof against 
them. Based on what happens in other equipment, requiring that the person 
changing this take a clear, unambigous, deliberate action to unlock the radio 
and therefor be clear that they are responsible for anything it does wrong is 
probably good enough. It probably does need to be something other than just a 
software setting though.

What I think would be a good approach is the jumper/0-ohm resister approach 
(google does this with the chrome laptops, open them up, remove a washer that 
acts as a jumper, and it's now unlocked). With the jumper in place, the firmware 
and country code cannot be altered, with it removed, it can be (and a nice big 
warning in the documentation that doing so may be illegal for people to ignore)

It's just not possible to prevent the OS from trying to set the channel 
inappropriately unless you are going to lock down the device to the point that 
you don't allow any software updates at all

David Lang

On Tue, 9 Dec 2014, Eric Schultz wrote:

> Date: Tue, 9 Dec 2014 14:34:14 -0600
> From: Eric Schultz <eschultz at prplfoundation.org>
> To: David Lang <david at lang.hm>
> Cc: Dave Taht <dave.taht at gmail.com>,
>     "cerowrt-devel at lists.bufferbloat.net"
>     <cerowrt-devel at lists.bufferbloat.net>
> Subject: Re: [Cerowrt-devel] New FCC requirements and CeroWrt
> David,
> Thanks for the response. We're getting advice from the EFF right now,
> and hopefully other groups, on what the requirement is. It's
> admittedly vague and hard to separate what the FCC means versus what
> developers might think.
> You bring up a lot of good points that I need to add to the page to
> clarify. I'm not sure in this case you can separate the radio
> frequency parameters from the kernel in the case of OpenWrt. I'm not a
> kernel engineer but I've tried to general understanding of how the
> frequency authorization works in OpenWrt and Linux.
> As I understand it, the system for deciding which frequencies to use
> is included as part of the kernel in OpenWrt. The kernel uses the
> frequency database to decide on what commands to send to the wifi
> driver (which include changing frequency, using DFS, etc). The driver
> is clearly part of the device at this point. But how should the driver
> verify that the commands coming in comply with requirements? It's not
> entirely clear. And how does the manufacturer guarantee that only
> authorized updates are made to the device?
> I want to make clear, the wiki page does not include recommendations.
> These were ideas that one of our members were throwing around
> internally with their development and legal team. They've asked me to
> try to come up with better solutions since they don't really like any
> of the ones they've come up with internally.  I'm contacting folks to
> try to come up with recommendations for companies so they don't go for
> the more extreme routes that unnecessarily lock down devices and hurt
> the community.
> Eric
> On Tue, Dec 9, 2014 at 2:14 PM, David Lang <david at lang.hm> wrote:
>> We really need to find out what the new FCC requirements are.
>> People have been claiming that the FCC requires all sorts of lockdowns that
>> they don't actually require for decades (when I first got into Ham Radio, we
>> were hearing that any radio able to operate on the business bands had to be
>> locked down to prevent the owner from changing it's frequency. It wasn't
>> true)
>> If they are saying that the RF portion can't be modified in a Software
>> Defined Radio, that would be somewhat reasonable, saying that the software
>> implementing the 802.11(whatever) protocol on that RF portion must be locked
>> down is less so, and saying that the main OS on the router must be locked
>> down is completely unreasonable.
>> I would be surprised if they required that the OS can't be changed.
>> As for the implementation of the 802.11(whatever) protocol, I would be
>> surprised if they required this to be locked down, but not dumbfounded
>> now that I've finished the rant, reading the statement quoted on that wiki
>> page:
>>> Applications for certification of U-NII devices in the 5.15-5.35 GHz and
>>> the 5.47-5.85 GHz bands must include a high level operational description of
>>> the security procedures that control the radio frequency operating
>>> parameters and ensure that unauthorized modifications cannot be made.
>> All that it is talking about is the radio frequency parameters.
>> The followup/clarification is again talking about the RF parameters.
>> Remember, when the FCC is talking about a 'device', they are talking about
>> the radio, not the entire computer that has a radio as part of it.
>> According to the background, they are worried about interference with radar,
>> so this could mean that the firmware needs to have a mechansim to detect the
>> radar and not transmit on that frequency, but this is only a few channels.
>> You could still have an opensource, non locked down firmware that just
>> didn't give you the option of using those channels, and a signed firmware
>> that did.
>> This does not require secure boot or any of the other lockdown methods that
>> are being talked about on that page. I hope these are not the "official"
>> openwrt recommendations (and if they are, why are they not on an openwrt
>> page?)
>> David Lang
>> On Tue, 9 Dec 2014, Eric Schultz wrote:
>>> Dave,
>>> Thanks for the quick response and I appreciate your passion.
>>> No one here wants Secure Boot or DRM at all. I personally find the
>>> idea abhorrent and no one at prpl wants it. The difficulty is figuring
>>> out how companies can comply with the regulation in a way that doesn't
>>> require hardware be locked down. I wish I could avoid ever thinking of
>>> this topic but unfortunately, if companies don't find a solution that
>>> fulfills the FCC's requirements, they're going to go with DRM. I want
>>> to see if we can give manufacturers a solution that avoids DRM
>>> entirely.
>>> I'd be happy to learn more about the make-wifi-fast effort and to see
>>> how we can facilitate it's success.
>>> Thanks a ton,
>>> Eric
>>> On Tue, Dec 9, 2014 at 11:49 AM, Dave Taht <dave.taht at gmail.com> wrote:
>>>> On Tue, Dec 9, 2014 at 9:11 AM, Eric Schultz
>>>> <eschultz at prplfoundation.org> wrote:
>>>>> All,
>>>>> I work for the prpl Foundation, an open source foundation organized by
>>>>> a number of companies, most related to MIPS. One project we work with
>>>>> externally is the OpenWrt project. Recently one of our members
>>>>> mentioned a new FCC requirement (described at
>>>>> http://wiki.prplfoundation.org/wiki/Complying_with_FCC_rules_on_5ghz_wifi)
>>>>> which requires wifi hardware devices to restrict modifications in ways
>>>>> that were not previously required. Some of the suggestions the company
>>>>> had internally for complying would be to use features like Secure Boot
>>>>> and other types of DRM-like mechanisms to prevent routers from being
>>>>> modified. This obviously would be quite bad for the OpenWrt ecosystem
>>>> It would be bad for everyone. Worse, since the research contingent
>>>> making progress on keeping wifi working in the first place in the face
>>>> of enormous growth, is centered around the ath9k chipset, additional
>>>> rules and regulations centered around DRM are likely to choke off
>>>> further development of then new ideas and techniques needed to keep it
>>>> working.
>>>>> so we agreed as a group
>>>>> to try to provide hardware companies with a way of complying without
>>>>> harming the community.
>>>> My view is mildly more extreme - the 2.4 and 5.8 ghz spectrum currently
>>>> allocated to wifi is the *public's* spectrum.
>>>> I am deeply concerned about  further intrusions on it by things like
>>>> this:
>>>> https://www.qualcomm.com/products/lte/unlicensed
>>>> and we need more spectrum, not less, in order to keep wifi for
>>>> everyone, working.
>>>>> I'm looking to find individuals (and other companies!) interested in
>>>>> working with myself and the foundation, companies, the OpenWrt
>>>>> community
>>>>> and eventually regulators to provide guidance to hardware
>>>>> companies on how to best comply with these rules.
>>>> I intend to continue ignoring them to what extent I can. Regrettably
>>>> this situation is contributing to community members being unable to
>>>> apply new queue management techniques to new standards like 802.11ac,
>>>> and seems to be the source of all the proprietary ac firmware.
>>>> I think a first step would merely to be for a big maker to publicly
>>>> release their 802.11ac firmware and let the chips fall where they may.
>>>>> If you're interested
>>>>> in getting involved or just would like to know more, please get in
>>>>> touch with me. We want to make sure that routers are hackable
>>>>> and we could use all the help we can get.
>>>> +10. I would like to see prpl participating in the make-wifi-fast effort,
>>>> also.
>>>> http://snapon.lab.bufferbloat.net/~d/ieee802.11-sept-17-2014/11-14-1265-00-0wng-More-on-Bufferbloat.pdf
>>>>> Thanks and I look forward to working with you,
>>>>> Eric
>>>>> --
>>>>> Eric Schultz, Community Manager, prpl Foundation
>>>>> http://www.prplfoundation.org
>>>>> eschultz at prplfoundation.org
>>>>> cell: 920-539-0404
>>>>> skype: ericschultzwi
>>>>> @EricPrpl
>>>>> _______________________________________________
>>>>> Cerowrt-devel mailing list
>>>>> Cerowrt-devel at lists.bufferbloat.net
>>>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel
>>>> --
>>>> Dave Täht
>>>> thttp://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks
>>> --
>>> Eric Schultz, Community Manager, prpl Foundation
>>> http://www.prplfoundation.org
>>> eschultz at prplfoundation.org
>>> cell: 920-539-0404
>>> skype: ericschultzwi
>>> @EricPrpl
>>> _______________________________________________
>>> Cerowrt-devel mailing list
>>> Cerowrt-devel at lists.bufferbloat.net
>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel

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