[PATCH] mt76x2: fix possible NULL pointer dereferencing in mt76x2_tx()

[Lorenzo Bianconi]

Fix a theoretical NULL pointer dereferencing in mt76x2_tx routine that
can occurs for injected frames in a monitor vif since vif pointer could
be NULL for that interfaces

Fixes: 23405236460b ("mt76: fix transmission of encrypted mgmt frames")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianc...@redhat.com>
---
 drivers/net/wireless/mediatek/mt76/mt76x2_tx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x2_tx.c 
b/drivers/net/wireless/mediatek/mt76/mt76x2_tx.c
index 534e4bf9a34c..e46eafc4c436 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x2_tx.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x2_tx.c
@@ -36,9 +36,12 @@ void mt76x2_tx(struct ieee80211_hw *hw, struct 
ieee80211_tx_control *control,
 
                msta = (struct mt76x2_sta *) control->sta->drv_priv;
                wcid = &msta->wcid;
+               /* sw encrypted frames */
+               if (!info->control.hw_key && wcid->hw_key_idx != -1)
+                       control->sta = NULL;
        }
 
-       if (vif || (!info->control.hw_key && wcid->hw_key_idx != -1)) {
+       if (vif && !control->sta) {
                struct mt76x2_vif *mvif;
 
                mvif = (struct mt76x2_vif *) vif->drv_priv;
-- 
2.16.2