Re: GCMP and other unknown ciphers

[Emil Velikov <emil.l.velikov@gmail.com>]

Hi Denis,

Sorry for the late reply - been busy with some non-computer stuff.

On Thu, 6 Oct 2022 at 15:34, Denis Kenzior <denkenz@gmail.com> wrote:
>
> Hi Emil,
>
> On 10/6/22 08:22, Emil Velikov wrote:
> > Greetings team,
> >
> > Recently we've noticed that IWD fails to connect to WPA2-PSK networks
> > whenever GCMP+CCMP cipher is used. Browsing through the IWD code-base
> > it appears that it lacks support for GCMP, GCMP-256 and CCMP-256
> > amongst others.
>
> We do not support or select GCMP. But I'm not sure why this would prevent a
> connection?  We would always select CCMP instead.  See wiphy_select_cipher().
>
> Hmm... maybe we reject GCMP at a lower layer...?  Try the attached patch?
>

Now that I've got the hardware at hand, it looks like iwd does not
list the network at all. I will try your patch and report shortly.

Details:
 - Nighthawk X10 running dd-wrt
 - WPA2 Personal (without SHA256)
 - CCMP-128(AES) + GCMP

> >
> > Was my analysis correct - is GCMP supported? Are there any plans on doing so?
>
> No real plans, patches are always welcome.
>
Do you have a rough estimate of how much work that might be -  are we
talking about weeks or months? How does one get access to the 802.11
spec these days?

> >
> > Somewhat relatedly - is there a configuration knob that one can switch
> > and let IWD fall-back to the other supported ciphers? In the GCMP+CCMP
> > case, we can opt for CCMP for example.
> >
>
> This should already happen.
>
That was my assumption as well, yet empirically it does not.

Thanks again
Emil