wifi: mt76: add a wrapper for wcid access with validation

Several places use rcu_dereference to get a wcid entry without validating
if the index exceeds the array boundary. Fix this by using a helper function,
which handles validation.

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>

Author: nbd168

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -1224,6 +1224,16 @@ static inline int mt76_wed_dma_setup(struct mt76_dev *dev, struct mt76_queue *q,
 #define mt76_dereference(p, dev) \
 	rcu_dereference_protected(p, lockdep_is_held(&(dev)->mutex))
 
+static inline struct mt76_wcid *
+__mt76_wcid_ptr(struct mt76_dev *dev, u16 idx)
+{
+	if (idx >= ARRAY_SIZE(dev->wcid))
+		return NULL;
+	return rcu_dereference(dev->wcid[idx]);
+}
+
+#define mt76_wcid_ptr(dev, idx) __mt76_wcid_ptr(&(dev)->mt76, idx)
+
 struct mt76_dev *mt76_alloc_device(struct device *pdev, unsigned int size,
 				   const struct ieee80211_ops *ops,
 				   const struct mt76_driver_ops *drv_ops);

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

@@ -44,7 +44,7 @@ mt7603_rx_loopback_skb(struct mt7603_dev *dev, struct sk_buff *skb)
 	if (idx >= MT7603_WTBL_STA - 1)
 		goto free;
 
-	wcid = rcu_dereference(dev->mt76.wcid[idx]);
+	wcid = mt76_wcid_ptr(dev, idx);
 	if (!wcid)
 		goto free;
 

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

@@ -487,10 +487,7 @@ mt7603_rx_get_wcid(struct mt7603_dev *dev, u8 idx, bool unicast)
 	struct mt7603_sta *sta;
 	struct mt76_wcid *wcid;
 
-	if (idx >= MT7603_WTBL_SIZE)
-		return NULL;
-
-	wcid = rcu_dereference(dev->mt76.wcid[idx]);
+	wcid = mt76_wcid_ptr(dev, idx);
 	if (unicast || !wcid)
 		return wcid;
 
@@ -1266,12 +1263,9 @@ void mt7603_mac_add_txs(struct mt7603_dev *dev, void *data)
 	if (pid == MT_PACKET_ID_NO_ACK)
 		return;
 
-	if (wcidx >= MT7603_WTBL_SIZE)
-		return;
-
 	rcu_read_lock();
 
-	wcid = rcu_dereference(dev->mt76.wcid[wcidx]);
+	wcid = mt76_wcid_ptr(dev, wcidx);
 	if (!wcid)
 		goto out;
 

drivers/net/wireless/mediatek/mt76/mt7615/mac.c

@@ -90,10 +90,7 @@ static struct mt76_wcid *mt7615_rx_get_wcid(struct mt7615_dev *dev,
 	struct mt7615_sta *sta;
 	struct mt76_wcid *wcid;
 
-	if (idx >= MT7615_WTBL_SIZE)
-		return NULL;
-
-	wcid = rcu_dereference(dev->mt76.wcid[idx]);
+	wcid = mt76_wcid_ptr(dev, idx);
 	if (unicast || !wcid)
 		return wcid;
 
@@ -1504,7 +1501,7 @@ static void mt7615_mac_add_txs(struct mt7615_dev *dev, void *data)
 
 	rcu_read_lock();
 
-	wcid = rcu_dereference(dev->mt76.wcid[wcidx]);
+	wcid = mt76_wcid_ptr(dev, wcidx);
 	if (!wcid)
 		goto out;
 

drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c

@@ -1172,7 +1172,7 @@ void mt76_connac2_txwi_free(struct mt76_dev *dev, struct mt76_txwi_cache *t,
 		wcid_idx = wcid->idx;
 	} else {
 		wcid_idx = le32_get_bits(txwi[1], MT_TXD1_WLAN_IDX);
-		wcid = rcu_dereference(dev->wcid[wcid_idx]);
+		wcid = __mt76_wcid_ptr(dev, wcid_idx);
 
 		if (wcid && wcid->sta) {
 			sta = container_of((void *)wcid, struct ieee80211_sta,

drivers/net/wireless/mediatek/mt76/mt76x02.h

@@ -262,10 +262,7 @@ mt76x02_rx_get_sta(struct mt76_dev *dev, u8 idx)
 {
 	struct mt76_wcid *wcid;
 
-	if (idx >= MT76x02_N_WCIDS)
-		return NULL;
-
-	wcid = rcu_dereference(dev->wcid[idx]);
+	wcid = __mt76_wcid_ptr(dev, idx);
 	if (!wcid)
 		return NULL;
 

drivers/net/wireless/mediatek/mt76/mt76x02_mac.c

@@ -564,9 +564,7 @@ void mt76x02_send_tx_status(struct mt76x02_dev *dev,
 
 	rcu_read_lock();
 
-	if (stat->wcid < MT76x02_N_WCIDS)
-		wcid = rcu_dereference(dev->mt76.wcid[stat->wcid]);
-
+	wcid = mt76_wcid_ptr(dev, stat->wcid);
 	if (wcid && wcid->sta) {
 		void *priv;
 

drivers/net/wireless/mediatek/mt76/mt7915/mac.c

@@ -56,10 +56,7 @@ static struct mt76_wcid *mt7915_rx_get_wcid(struct mt7915_dev *dev,
 	struct mt7915_sta *sta;
 	struct mt76_wcid *wcid;
 
-	if (idx >= ARRAY_SIZE(dev->mt76.wcid))
-		return NULL;
-
-	wcid = rcu_dereference(dev->mt76.wcid[idx]);
+	wcid = mt76_wcid_ptr(dev, idx);
 	if (unicast || !wcid)
 		return wcid;
 
@@ -917,7 +914,7 @@ mt7915_mac_tx_free(struct mt7915_dev *dev, void *data, int len)
 			u16 idx;
 
 			idx = FIELD_GET(MT_TX_FREE_WLAN_ID, info);
-			wcid = rcu_dereference(dev->mt76.wcid[idx]);
+			wcid = mt76_wcid_ptr(dev, idx);
 			sta = wcid_to_sta(wcid);
 			if (!sta)
 				continue;
@@ -1013,12 +1010,9 @@ static void mt7915_mac_add_txs(struct mt7915_dev *dev, void *data)
 	if (pid < MT_PACKET_ID_WED)
 		return;
 
-	if (wcidx >= mt7915_wtbl_size(dev))
-		return;
-
 	rcu_read_lock();
 
-	wcid = rcu_dereference(dev->mt76.wcid[wcidx]);
+	wcid = mt76_wcid_ptr(dev, wcidx);
 	if (!wcid)
 		goto out;
 

drivers/net/wireless/mediatek/mt76/mt7915/mcu.c

@@ -3986,7 +3986,7 @@ int mt7915_mcu_wed_wa_tx_stats(struct mt7915_dev *dev, u16 wlan_idx)
 
 	rcu_read_lock();
 
-	wcid = rcu_dereference(dev->mt76.wcid[wlan_idx]);
+	wcid = mt76_wcid_ptr(dev, wlan_idx);
 	if (wcid)
 		wcid->stats.tx_packets += le32_to_cpu(res->tx_packets);
 	else

drivers/net/wireless/mediatek/mt76/mt7915/mmio.c

@@ -587,12 +587,9 @@ static void mt7915_mmio_wed_update_rx_stats(struct mtk_wed_device *wed,
 
 	dev = container_of(wed, struct mt7915_dev, mt76.mmio.wed);
 
-	if (idx >= mt7915_wtbl_size(dev))
-		return;
-
 	rcu_read_lock();
 
-	wcid = rcu_dereference(dev->mt76.wcid[idx]);
+	wcid = mt76_wcid_ptr(dev, idx);
 	if (wcid) {
 		wcid->stats.rx_bytes += le32_to_cpu(stats->rx_byte_cnt);
 		wcid->stats.rx_packets += le32_to_cpu(stats->rx_pkt_cnt);