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Date:   Mon, 25 May 2020 11:31:42 +0200
From:   Stanislaw Gruszka <stf_xl@wp.pl>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     Julian Calaby <julian.calaby@gmail.com>,
        Rui Salvaterra <rsalvaterra@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Larry Finger <Larry.Finger@lwfinger.net>,
        linux-wireless@vger.kernel.org
Subject: Re: [RFC PATCH] rt2800lib: unconditionally enable MFP
Message-ID: <20200525093142.GA926004@wp.pl>
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On Mon, May 25, 2020 at 11:15:29AM +0200, Johannes Berg wrote:
> On Sun, 2020-05-24 at 14:39 +0200, Stanislaw Gruszka wrote:
> > 
> > > And once mac80211 is smart enough to make those decisions, couldn't we
> > > just enable MFP by default?
> 
> For the record, I don't think we'd really want to add such a thing to
> mac80211 ... easier done in the driver.
> 
> > If we will have indicator from mac80211 that MFP is configured, we can
> > just return -EOPNOTSUPP from rt2x00mac_set_key() for CCMP and that will
> > make MFP work without specifying nohwcrypt module parameter - software
> > encryption will be used anyway.
> 
> Not sure mac80211 really knows? Hmm.

After looking at this a bit more, seems we have indicator of MFP being
used in ieee80211_sta structure. So maybe adding check like below
will allow to remove nohwcrypt rt2x00 requirement for MFP ?

diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c
index 32efbc8e9f92..241e42bb0fd2 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00mac.c
@@ -468,7 +468,7 @@ int rt2x00mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 	if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
 		return 0;
 
-	if (!rt2x00_has_cap_hw_crypto(rt2x00dev))
+	if (!rt2x00_has_cap_hw_crypto(rt2x00dev) || sta->mfp)
 		return -EOPNOTSUPP;
 
 	/*

Stanislaw