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From: Johannes Berg <johannes@sipsolutions.net>
To: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>,
	"hostap@lists.infradead.org" <hostap@lists.infradead.org>
Subject: Re: [PATCH V2 0/9] nl80211: add support for PTK/GTK handshake offload
Date: Fri, 09 Jun 2017 11:08:04 +0200	[thread overview]
Message-ID: <1496999284.2424.7.camel@sipsolutions.net> (raw)
In-Reply-To: <d41f58e9-b12e-9e52-a0fb-b674d278353b@broadcom.com> (sfid-20170603_100839_987129_9FE5CC46)

Hi Arend,

Sorry about the delay.

> > Then you have to support NEW_KEY (AP case) and then using NEW_KEY
> > to
> > detect whether or not a wpa_s configuration option to not use
> > offloaded
> > 4-way-HS can be used will not work correctly.
> > 
> > I don't really see that this is a sensible configuration, but I
> > could
> > imagine it existing if somebody "bolted on" AP functionality for a
> > client-side chipset or something like that.

> So I want to get back to this as to assure we have the same
> understanding. First off, the proposed offloads are STA-only. 

Right. But we at least also want to have them for AP mode, which
answers your below question.

> So if a
> driver supports STA and AP mode and the 4-way-HS offload, we could
> already have the case you describe here. So not really a "bolted on"
> scenario I would say.

But if you say you don't have it in AP mode, or you didn't even think
about it in AP mode yet, then I think you're right and the "bolted on"
part doesn't really apply (*).

However, this does mean that checking for NEW_KEY support _isn't_
sufficient to understand whether or not the device also supports doing
the 4-way-HS in the host, because the device might _not_ support that
in client mode, yet implement NEW_KEY for AP mode, right?

In any case - I don't think this changes much my opinion. I think that
newer wpa_s should always use the offload where available, and if
there's a debug option to turn that off, and that debug option causes
failures because the driver rejects the NEW_KEY command, rather than
causing an up-front configuration failure because wpa_s knows that the
NEW_KEY wouldn't be supported, then I don't think for a debug option
that makes a big difference. For something that higher layers might
need to set, it would make a difference - but that's not at stake here.

johannes

(*) my line of thinking was that if you have the necessary state
machine for client in the firmware, then it's not a huge step to also
have it for AP, since you have the crypto primitives for it

  reply	other threads:[~2017-06-09  9:08 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-03 10:42 [PATCH V2 0/9] nl80211: add support for PTK/GTK handshake offload Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 1/9] cfg80211: support 4-way handshake offloading for WPA/WPA2-PSK Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 2/9] cfg80211: support 4-way handshake offloading for 802.1X Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 3/9] nl80211: add authorized flag to CONNECT event Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 4/9] nl80211: add authorized flag to ROAM event Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 5/9] nl80211: remove desciption about request from NL80211_CMD_ROAM Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 6/9] brcmfmac: support 4-way handshake offloading for WPA/WPA2-PSK Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 7/9] brcmfmac: support 4-way handshake offloading for 802.1X Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 8/9] brcmfmac: switch to using cfg80211_connect_done() Arend van Spriel
2017-05-03 10:42 ` [PATCH V2 9/9] brcmfmac: provide port authorized state in CONNECT event Arend van Spriel
2017-05-17 14:19 ` [PATCH V2 0/9] nl80211: add support for PTK/GTK handshake offload Johannes Berg
2017-05-18  8:18   ` Arend Van Spriel
2017-05-18  9:22     ` Johannes Berg
2017-05-18 10:29       ` Arend Van Spriel
2017-05-18 10:40         ` Johannes Berg
2017-05-18 12:48           ` Arend Van Spriel
2017-05-19 10:21             ` Johannes Berg
2017-05-22 10:14               ` Arend van Spriel
2017-05-22 10:28                 ` Johannes Berg
2017-05-29  9:18                   ` Arend van Spriel
2017-05-29  9:31                     ` Johannes Berg
2017-06-02 11:19                       ` Arend van Spriel
2017-06-02 13:56                         ` Johannes Berg
2017-06-03  8:08                       ` Arend van Spriel
2017-06-09  9:08                         ` Johannes Berg [this message]
2017-06-09 10:34                           ` Arend van Spriel
2017-06-09 10:59                             ` Johannes Berg
2017-06-09 11:21                               ` Arend van Spriel

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