[PATCH wireless 2/2] wifi: mt76: mt7996: clear cipher state on key removal for WED offload

[Joshua Klinesmith <joshuaklinesmith@gmail.com>]

Same issue as mt7915: link->mt76.cipher is set on key installation
but never cleared on removal. The WA firmware retains the stale
cipher in BSS_INFO, sets the protection bit on WED-offloaded
frames, and drops all plaintext traffic when encryption is
switched to open/none.

Reset link->mt76.cipher to zero and call mt7996_mcu_add_bss_info()
when the last group key is removed.

Fixes: 98686cd21624 ("wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices")
Cc: stable@vger.kernel.org
Signed-off-by: Joshua Klinesmith <joshuaklinesmith@gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7996/main.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
index 84f731b387..bf5fda6925 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
@@ -235,6 +235,21 @@ mt7996_set_hw_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 		} else {
 			if (idx == *wcid_keyidx)
 				*wcid_keyidx = -1;
+
+			if (!sta && link->mt76.cipher) {
+				struct ieee80211_bss_conf *lc;
+
+				lc = link_conf_dereference_protected(vif,
+								     link_id);
+				if (!lc)
+					lc = &vif->bss_conf;
+
+				link->mt76.cipher = 0;
+				mt7996_mcu_add_bss_info(link->phy, vif, lc,
+							&link->mt76,
+							msta_link, true);
+			}
+
 			continue;
 		}
 
-- 
2.43.0