mt76: mt7921: fix possible AOOB issue in mt7921_mcu_tx_rate_report

Fix possible array out of bound access in mt7921_mcu_tx_rate_report.
Remove unnecessary varibable in mt7921_mcu_tx_rate_report

Fixes: 1c099ab44727c ("mt76: mt7921: add MCU support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/91a1e8f6b6a3e6a929de560ed68132f6eb421720.1619187875.git.lorenzo@kernel.org

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
index 5f3d56d570a5ed0b9896a5bd6bd4165700b9af9d..67dc4b4cc09450b1cebe71824df4776e99b19286 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
@@ -402,20 +402,22 @@ static void
 mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb,
                          u16 wlan_idx)
 {
-       struct mt7921_mcu_wlan_info_event *wtbl_info =
-               (struct mt7921_mcu_wlan_info_event *)(skb->data);
-       struct rate_info rate = {};
-       u8 curr_idx = wtbl_info->rate_info.rate_idx;
-       u16 curr = le16_to_cpu(wtbl_info->rate_info.rate[curr_idx]);
-       struct mt7921_mcu_peer_cap peer = wtbl_info->peer_cap;
+       struct mt7921_mcu_wlan_info_event *wtbl_info;
        struct mt76_phy *mphy = &dev->mphy;
        struct mt7921_sta_stats *stats;
+       struct rate_info rate = {};
        struct mt7921_sta *msta;
        struct mt76_wcid *wcid;
+       u8 idx;
 
        if (wlan_idx >= MT76_N_WCIDS)
                return;
 
+       wtbl_info = (struct mt7921_mcu_wlan_info_event *)skb->data;
+       idx = wtbl_info->rate_info.rate_idx;
+       if (idx >= ARRAY_SIZE(wtbl_info->rate_info.rate))
+               return;
+
        rcu_read_lock();
 
        wcid = rcu_dereference(dev->mt76.wcid[wlan_idx]);
@@ -426,7 +428,8 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb,
        stats = &msta->stats;
 
        /* current rate */
-       mt7921_mcu_tx_rate_parse(mphy, &peer, &rate, curr);
+       mt7921_mcu_tx_rate_parse(mphy, &wtbl_info->peer_cap, &rate,
+                                le16_to_cpu(wtbl_info->rate_info.rate[idx]));
        stats->tx_rate = rate;
 out:
        rcu_read_unlock();