From edb3a9560e0c6668e8d47eaed70eec3c80bc5e62 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Fri, 16 Nov 2018 17:19:21 +0100 Subject: [PATCH] mt76: fix potential NULL pointer dereference in mt76_stop_tx_queues Starting from mac80211 commit a3024ca15127 ("mac80211: add an optional TXQ for other PS-buffered frames") and commit 73458fcb9377 ("mac80211: add an option for station management TXQ") a new per-sta queue has been introduced for bufferable management frames. sta->txq[IEEE80211_NUM_TIDS] is initialized just if the driver reports the following hw flags: - IEEE80211_HW_STA_MMPDU_TXQ - IEEE80211_HW_BUFF_MMPDU_TXQ This can produce a NULL pointer dereference in mt76_stop_tx_queues since mt76 iterates on all available sta tx queues assuming they are initialized by mac80211. This issue has been spotted analyzing the code (it has not triggered any crash yet) Signed-off-by: Lorenzo Bianconi Signed-off-by: Kalle Valo --- drivers/net/wireless/mediatek/mt76/tx.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c index 7cbce03aa65b9..aa426b838ffaf 100644 --- a/drivers/net/wireless/mediatek/mt76/tx.c +++ b/drivers/net/wireless/mediatek/mt76/tx.c @@ -400,7 +400,12 @@ void mt76_stop_tx_queues(struct mt76_dev *dev, struct ieee80211_sta *sta, for (i = 0; i < ARRAY_SIZE(sta->txq); i++) { struct ieee80211_txq *txq = sta->txq[i]; - struct mt76_txq *mtxq = (struct mt76_txq *) txq->drv_priv; + struct mt76_txq *mtxq; + + if (!txq) + continue; + + mtxq = (struct mt76_txq *)txq->drv_priv; spin_lock_bh(&mtxq->hwq->lock); mtxq->send_bar = mtxq->aggr && send_bar; -- 2.39.5