wifi: mt76: mt7996: fix possible NULL pointer dereference in mt7996_mac_write_txwi()

Fix possible NULL pointer dereference on mvif pointer in
mt7996_mac_write_txwi routine.

Fixes: 15ee62e73705 ("wifi: mt76: mt7996: enable BSS_CHANGED_BASIC_RATES support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/2637628a84f42ad6d7b774e706f041d5b45c8cb5.1685269638.git.lorenzo@kernel.org

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
index 39a4a73ef8e6a10bcdaafce6bbc96ba25705b7a9..9b0f6053e0fa6280a58c48e029a91d8a0061d4e3 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
@@ -1004,10 +1004,10 @@ void mt7996_mac_write_txwi(struct mt7996_dev *dev, __le32 *txwi,
 {
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_vif *vif = info->control.vif;
-       struct mt7996_vif *mvif = (struct mt7996_vif *)vif->drv_priv;
        u8 band_idx = (info->hw_queue & MT_TX_HW_QUEUE_PHY) >> 2;
        u8 p_fmt, q_idx, omac_idx = 0, wmm_idx = 0;
        bool is_8023 = info->flags & IEEE80211_TX_CTL_HW_80211_ENCAP;
+       struct mt7996_vif *mvif;
        u16 tx_count = 15;
        u32 val;
        bool beacon = !!(changed & (BSS_CHANGED_BEACON |
@@ -1015,7 +1015,8 @@ void mt7996_mac_write_txwi(struct mt7996_dev *dev, __le32 *txwi,
        bool inband_disc = !!(changed & (BSS_CHANGED_UNSOL_BCAST_PROBE_RESP |
                                         BSS_CHANGED_FILS_DISCOVERY));
 
-       if (vif) {
+       mvif = vif ? (struct mt7996_vif *)vif->drv_priv : NULL;
+       if (mvif) {
                omac_idx = mvif->mt76.omac_idx;
                wmm_idx = mvif->mt76.wmm_idx;
                band_idx = mvif->mt76.band_idx;
@@ -1081,12 +1082,16 @@ void mt7996_mac_write_txwi(struct mt7996_dev *dev, __le32 *txwi,
                struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
                bool mcast = ieee80211_is_data(hdr->frame_control) &&
                             is_multicast_ether_addr(hdr->addr1);
-               u8 idx = mvif->basic_rates_idx;
+               u8 idx = MT7996_BASIC_RATES_TBL;
 
-               if (mcast && mvif->mcast_rates_idx)
-                       idx = mvif->mcast_rates_idx;
-               else if (beacon && mvif->beacon_rates_idx)
-                       idx = mvif->beacon_rates_idx;
+               if (mvif) {
+                       if (mcast && mvif->mcast_rates_idx)
+                               idx = mvif->mcast_rates_idx;
+                       else if (beacon && mvif->beacon_rates_idx)
+                               idx = mvif->beacon_rates_idx;
+                       else
+                               idx = mvif->basic_rates_idx;
+               }
 
                txwi[6] |= cpu_to_le32(FIELD_PREP(MT_TXD6_TX_RATE, idx));
                txwi[3] |= cpu_to_le32(MT_TXD3_BA_DISABLE);