[p2p-hackers] Re: Penumbra Wifi Network

Alexander Pevzner pzz at pzz.msk.ru
Wed Jan 17 20:02:09 EST 2007


Andy Green wrote:

>> Please note, 802.11 chipsets manufactures are very rigid in disclosing
>> their driver sources, even under NDA.
> 
> There are two possibilities I can imagine:
> 
>  - Someone will figure out a way to do it without driver meddling.  For
> example, if the crypto is done by the 80211 stack as it is in many
> drivers currently, a single patch to the 80211 stack to disable crypto
> for the "Magic MAC" packets, and the technique of simply directing
> "Magic MAC" packets to the AP, and another patch to filter promiscuous
> mode might do it for many wifi cards

What operating system are you speaking about? On Windows encryption is
handled by driver (802.11 driver looks to the system as Ethernet with
million controls). On Linux, the "80211 stack" only used by Intel
driver. Atheros driver brings very similar stack with itself. From
another hand, on Linux this is not so difficult to modify all existent
drivers - there are not so much of them.

Encryption is normally performed by hardware. Software only maintains
encryption keys and policy. At least for Atheros, full per-frame control
is available for driver itself.

>  - The manufacturers might want to add it themselves once it is proven
> and well specified.  It costs almost nothing to them but is quite an
> attractive feature to the customer.

This is EXTREMELY HARD to obtain driver sources, unless your name is
Palm or similar :-)


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