Re: [PATCH 1/2] wifi: nl80211: force WLAN_AKM_SUITE_SAE in big endian in NL80211_CMD_EXTERNAL_AUTH

[Alexis Lothoré]

On 2/15/24 17:58, Kalle Valo wrote:
> Alexis Lothoré <alexis.lothore@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Alexis Lothoré <alexis.lothore@xxxxxxxxxxx>
> 
> A pointer to the discussion would be nice to have:
> 
> Link: https://lore.kernel.org/all/09eeb7d4-c922-45ee-a1ac-59942153dbce@xxxxxxxxxxx/
> 
> 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