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Subject: Re: [PATCH 04/11] wil6210: fix PTK re-key race
To:     Kalle Valo <kvalo@codeaurora.org>, Maya Erez <merez@codeaurora.org>
Cc:     Ahmad Masri <amasri@codeaurora.org>,
        linux-wireless@vger.kernel.org, wil6210@qti.qualcomm.com
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From:   Arend Van Spriel <arend.vanspriel@broadcom.com>
Message-ID: <ea0e8482-f4ba-3ed7-633d-06265e4f04e0@broadcom.com>
Date:   Wed, 11 Sep 2019 09:50:34 +0200
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On 9/10/2019 3:23 PM, Kalle Valo wrote:
> Maya Erez <merez@codeaurora.org> wrote:
> 
>> Fix a race between cfg80211 add_key call and transmitting of 4/4 EAP
>> packet. In case the transmit is delayed until after the add key takes
>> place, message 4/4 will be encrypted with the new key, and the
>> receiver side (AP) will drop it due to MIC error.
>>
>> Wil6210 will monitor and look for the transmitted packet 4/4 eap key.
>> In case add_key takes place before the transmission completed, then
>> wil6210 will let the FW store the key and wil6210 will notify the FW
>> to use the PTK key only after 4/4 eap packet transmission was
>> completed.
> 
> This is rather ugly but I guess still ok. Or what do people think?

The idea is similar to what we have in brcmfmac although it looks like a 
lot more code. So there seems precedent for the approach.

> But for a proper fix you should look at:
> 
> [PATCH v2] wpa_supplicant: Send EAPoL-Key frames over NL80211 where available
> 
> http://lists.infradead.org/pipermail/hostap/2019-September/040516.html

However, I agree that Denis did a better job with this and we should aim 
to use it. It is on my largish TODO list for brcmfmac.

Regards,
Arend