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Message-ID: <d539e013-7205-4661-9b13-b359e5bd8610@bootlin.com>
Date: Fri, 16 Feb 2024 09:21:54 +0100
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Subject: Re: [PATCH 1/2] wifi: nl80211: force WLAN_AKM_SUITE_SAE in big endian
 in NL80211_CMD_EXTERNAL_AUTH
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To: Kalle Valo <kvalo@kernel.org>
Cc: Johannes Berg <johannes@sipsolutions.net>,
 Ajay Singh <ajay.kathat@microchip.com>,
 Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
 linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
 Igor Mitsyanko <imitsyanko@quantenna.com>,
 Sergey Matyukevich <geomatsi@gmail.com>
References: <20240215-nl80211_fix_akm_suites_endianness-v1-0-57e902632f9d@bootlin.com>
 <20240215-nl80211_fix_akm_suites_endianness-v1-1-57e902632f9d@bootlin.com>
 <87cysxekbc.fsf@kernel.org>
From: =?UTF-8?Q?Alexis_Lothor=C3=A9?= <alexis.lothore@bootlin.com>
In-Reply-To: <87cysxekbc.fsf@kernel.org>
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On 2/15/24 17:58, Kalle Valo wrote:
> Alexis Lothoré <alexis.lothore@bootlin.com> writes:
> 
>> User-space supplicant (observed at least on wpa_supplicant) historically
>> parses the NL80211_ATTR_AKM_SUITES from the NL80211_CMD_EXTERNAL_AUTH
>> message as big endian _only_ when its value is WLAN_AKM_SUITE_SAE, while
>> processing anything else in host endian. This behavior makes any driver
>> relying on SAE external auth to switch AKM suite to big endian if it is
>> WLAN_AKM_SUITE_SAE. A fix bringing compatibility with both endianness
>> has been brought into wpa_supplicant, however we must keep compatibility
>> with older versions, while trying to reduce the occurences of this manual
>> conversion in wireless drivers.
>>
>> Add the be32 conversion specifically on WLAN_AKM_SUITE_SAE in nl80211 layer
>> to keep compatibility with older wpa_supplicant versions.
>>
>> Suggested-by: Johannes Berg <johannes@sipsolutions.net>
>> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
> 
> A pointer to the discussion would be nice to have:
> 
> Link: https://lore.kernel.org/all/09eeb7d4-c922-45ee-a1ac-59942153dbce@bootlin.com/
> 
> I assume Johannes can add that.

Ah yes, indeed. Johannes, please let me know if you prefer me to resend it with
the link in the commit message.

> Alexis, thanks so much for working on this! This has been bugging me for
> long but never found the time to investigate it.

I'm glad to help, especially since I have the corresponding hardware. This
warning was on my radar, and your last complaint about remaining sparse warnings
in the wireless tree eventually triggered the action :)

-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com