staging: wfx: fix BA when MFP is disabled but BSS is MFP capable

The protection of the management frames is mainly done by mac80211.
However, frames for the management of the BlockAck sessions are directly
sent by the device. These frames have to be protected if MFP is in use.
So the driver has to pass the MFP configuration to the device.

Until now, the driver directly read the RSN IE of the BSS. However, it
didn't work when the BSS was MFP capable (ieee80211w=1) and the local
device has disabled MFP (ieee80211w=0).

This patch read the MFP information directly from the struct
ieee80211_sta. This information take into account the MFP negotiated
during the association. In addition, the code is far simpler.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200825085828.399505-3-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/sta.c

@@ -323,36 +323,6 @@ void wfx_set_default_unicast_key(struct ieee80211_hw *hw,
 	hif_wep_default_key_id(wvif, idx);
 }
 
-static void wfx_set_mfp(struct wfx_vif *wvif,
-			struct cfg80211_bss *bss)
-{
-	const int pairwise_cipher_suite_count_offset = 8 / sizeof(u16);
-	const int pairwise_cipher_suite_size = 4 / sizeof(u16);
-	const int akm_suite_size = 4 / sizeof(u16);
-	const u16 *ptr = NULL;
-	bool mfpc = false;
-	bool mfpr = false;
-
-	/* 802.11w protected mgmt frames */
-
-	/* retrieve MFPC and MFPR flags from beacon or PBRSP */
-
-	rcu_read_lock();
-	if (bss)
-		ptr = (const u16 *)ieee80211_bss_get_ie(bss, WLAN_EID_RSN);
-
-	if (ptr) {
-		ptr += pairwise_cipher_suite_count_offset;
-		ptr += 1 + pairwise_cipher_suite_size * *ptr;
-		ptr += 1 + akm_suite_size * *ptr;
-		mfpr = *ptr & BIT(6);
-		mfpc = *ptr & BIT(7);
-	}
-	rcu_read_unlock();
-
-	hif_set_mfp(wvif, mfpc, mfpr);
-}
-
 void wfx_reset(struct wfx_vif *wvif)
 {
 	struct wfx_dev *wdev = wvif->wdev;
@@ -400,7 +370,6 @@ static void wfx_do_join(struct wfx_vif *wvif)
 	}
 	rcu_read_unlock();
 
-	wfx_set_mfp(wvif, bss);
 	cfg80211_put_bss(wvif->wdev->hw->wiphy, bss);
 
 	wvif->join_in_progress = true;
@@ -427,6 +396,9 @@ int wfx_sta_add(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 
 	sta_priv->vif_id = wvif->id;
 
+	if (vif->type == NL80211_IFTYPE_STATION)
+		hif_set_mfp(wvif, sta->mfp, sta->mfp);
+
 	// In station mode, the firmware interprets new link-id as a TDLS peer.
 	if (vif->type == NL80211_IFTYPE_STATION && !sta->tdls)
 		return 0;