rtw89: Fix variable dereferenced before check 'sta'

The pointer rtwsta is dereferencing pointer sta before sta is being null
checked. Fix this by assigning sta->drv_priv to rtwsta only if sta is not
NULL, otherwise just NULL.

Fixes: e3ec7017f6a2 ("rtw89: add Realtek 802.11ax driver")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211022061242.8383-1-pkshih@realtek.com

diff --git a/drivers/net/wireless/realtek/rtw89/core.c b/drivers/net/wireless/realtek/rtw89/core.c
index 06fb6e5..d02ec5a 100644 (file)
--- a/drivers/net/wireless/realtek/rtw89/core.c
+++ b/drivers/net/wireless/realtek/rtw89/core.c
@@ -1412,7 +1412,7 @@ static void rtw89_core_ba_work(struct work_struct *work)
        list_for_each_entry_safe(rtwtxq, tmp, &rtwdev->ba_list, list) {
                struct ieee80211_txq *txq = rtw89_txq_to_txq(rtwtxq);
                struct ieee80211_sta *sta = txq->sta;
-               struct rtw89_sta *rtwsta = (struct rtw89_sta *)sta->drv_priv;
+               struct rtw89_sta *rtwsta = sta ? (struct rtw89_sta *)sta->drv_priv : NULL;
                u8 tid = txq->tid;
 
                if (!sta) {
@@ -1462,7 +1462,7 @@ static void rtw89_core_txq_check_agg(struct rtw89_dev *rtwdev,
        struct ieee80211_hw *hw = rtwdev->hw;
        struct ieee80211_txq *txq = rtw89_txq_to_txq(rtwtxq);
        struct ieee80211_sta *sta = txq->sta;
-       struct rtw89_sta *rtwsta = (struct rtw89_sta *)sta->drv_priv;
+       struct rtw89_sta *rtwsta = sta ? (struct rtw89_sta *)sta->drv_priv : NULL;
 
        if (unlikely(skb_get_queue_mapping(skb) == IEEE80211_AC_VO))
                return;
@@ -1534,7 +1534,7 @@ static bool rtw89_core_txq_agg_wait(struct rtw89_dev *rtwdev,
 {
        struct rtw89_txq *rtwtxq = (struct rtw89_txq *)txq->drv_priv;
        struct ieee80211_sta *sta = txq->sta;
-       struct rtw89_sta *rtwsta = (struct rtw89_sta *)sta->drv_priv;
+       struct rtw89_sta *rtwsta = sta ? (struct rtw89_sta *)sta->drv_priv : NULL;
 
        if (!sta || rtwsta->max_agg_wait <= 0)
                return false;