mt76: mt7603: fix input validation issues for powersave-filtered frames

Before extracting the tid out of the packet, check if it was qos-data.
Only accept tid values 0-7
Also, avoid accepting the hardware queue as skb queue mapping, it could
lead to an overrun. Instead, derive the hardware queue from the tid number,
in order to avoid issues with packets being filtered multiple times.
This also fixes a mismatch between hardware and software queue indexes.
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7603/dma.c

@@ -30,6 +30,16 @@ mt7603_init_tx_queue(struct mt7603_dev *dev, struct mt76_sw_queue *q,
 static void
 mt7603_rx_loopback_skb(struct mt7603_dev *dev, struct sk_buff *skb)
 {
+	static const u8 tid_to_ac[8] = {
+		IEEE80211_AC_BE,
+		IEEE80211_AC_BK,
+		IEEE80211_AC_BK,
+		IEEE80211_AC_BE,
+		IEEE80211_AC_VI,
+		IEEE80211_AC_VI,
+		IEEE80211_AC_VO,
+		IEEE80211_AC_VO
+	};
 	__le32 *txd = (__le32 *)skb->data;
 	struct ieee80211_hdr *hdr;
 	struct ieee80211_sta *sta;
@@ -38,7 +48,7 @@ mt7603_rx_loopback_skb(struct mt7603_dev *dev, struct sk_buff *skb)
 	void *priv;
 	int idx;
 	u32 val;
-	u8 tid;
+	u8 tid = 0;
 
 	if (skb->len < MT_TXD_SIZE + sizeof(struct ieee80211_hdr))
 		goto free;
@@ -56,15 +66,16 @@ mt7603_rx_loopback_skb(struct mt7603_dev *dev, struct sk_buff *skb)
 
 	priv = msta = container_of(wcid, struct mt7603_sta, wcid);
 	val = le32_to_cpu(txd[0]);
-	skb_set_queue_mapping(skb, FIELD_GET(MT_TXD0_Q_IDX, val));
-
 	val &= ~(MT_TXD0_P_IDX | MT_TXD0_Q_IDX);
 	val |= FIELD_PREP(MT_TXD0_Q_IDX, MT_TX_HW_QUEUE_MGMT);
 	txd[0] = cpu_to_le32(val);
 
 	sta = container_of(priv, struct ieee80211_sta, drv_priv);
 	hdr = (struct ieee80211_hdr *)&skb->data[MT_TXD_SIZE];
-	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
+	if (ieee80211_is_data_qos(hdr->frame_control))
+		tid = *ieee80211_get_qos_ctl(hdr) &
+		      IEEE80211_QOS_CTL_TAG1D_MASK;
+	skb_set_queue_mapping(skb, tid_to_ac[tid]);
 	ieee80211_sta_set_buffered(sta, tid, true);
 
 	spin_lock_bh(&dev->ps_lock);