[PATCH] wifi: mt76: mt7921: validate capability TLV extents

[Pengpeng Hou]

The NIC capability walker can accept truncated generic TLV headers or
payloads, and its type-specific consumers read fixed payloads without
proving that the current TLV contains those bytes.

Reject malformed generic extents and require every known capability type
to provide its minimum payload before parsing or copying it.

Fixes: dab35009fc1c ("wifi: mt76: mt7921: move connac nic capability handling to mt7921")
Signed-off-by: Pengpeng Hou <pengpeng at iscas.ac.cn>
---
 drivers/net/wireless/mediatek/mt76/mt7921/mcu.c | 89 ++++++++++++++++---------
 1 file changed, 59 insertions(+), 30 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
index a118a301564c8..8e6be9f63659a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
@@ -515,21 +515,38 @@ static int mt7921_load_clc(struct mt792x_dev *dev, const char *fw_name)
 	return ret;
 }
 
+struct mt7921_tx_resource {
+	__le32 version;
+	__le32 pse_data_quota;
+	__le32 pse_mcu_quota;
+	__le32 ple_data_quota;
+	__le32 ple_mcu_quota;
+	__le16 pse_page_size;
+	__le16 ple_page_size;
+	u8 pp_padding;
+	u8 pad[3];
+} __packed;
+
+struct mt7921_phy_cap {
+	u8 ht;
+	u8 vht;
+	u8 _5g;
+	u8 max_bw;
+	u8 nss;
+	u8 dbdc;
+	u8 tx_ldpc;
+	u8 rx_ldpc;
+	u8 tx_stbc;
+	u8 rx_stbc;
+	u8 hw_path;
+	u8 he;
+} __packed;
+
 static void mt7921_mcu_parse_tx_resource(struct mt76_dev *dev,
 					 struct sk_buff *skb)
 {
 	struct mt76_sdio *sdio = &dev->sdio;
-	struct mt7921_tx_resource {
-		__le32 version;
-		__le32 pse_data_quota;
-		__le32 pse_mcu_quota;
-		__le32 ple_data_quota;
-		__le32 ple_mcu_quota;
-		__le16 pse_page_size;
-		__le16 ple_page_size;
-		u8 pp_padding;
-		u8 pad[3];
-	} __packed * tx_res;
+	struct mt7921_tx_resource *tx_res;
 
 	tx_res = (struct mt7921_tx_resource *)skb->data;
 	sdio->sched.pse_data_quota = le32_to_cpu(tx_res->pse_data_quota);
@@ -545,20 +562,7 @@ static void mt7921_mcu_parse_tx_resource(struct mt76_dev *dev,
 static void mt7921_mcu_parse_phy_cap(struct mt76_dev *dev,
 				     struct sk_buff *skb)
 {
-	struct mt7921_phy_cap {
-		u8 ht;
-		u8 vht;
-		u8 _5g;
-		u8 max_bw;
-		u8 nss;
-		u8 dbdc;
-		u8 tx_ldpc;
-		u8 rx_ldpc;
-		u8 tx_stbc;
-		u8 rx_stbc;
-		u8 hw_path;
-		u8 he;
-	} __packed * cap;
+	struct mt7921_phy_cap *cap;
 
 	enum {
 		WF0_24G,
@@ -603,31 +607,56 @@ static int mt7921_mcu_get_nic_capability(struct mt792x_phy *mphy)
 		} __packed * tlv = (struct tlv_hdr *)skb->data;
 		int len;
 
-		if (skb->len < sizeof(*tlv))
-			break;
+		if (skb->len < sizeof(*tlv)) {
+			ret = -EINVAL;
+			goto out;
+		}
 
 		skb_pull(skb, sizeof(*tlv));
 
 		len = le32_to_cpu(tlv->len);
-		if (skb->len < len)
-			break;
+		if (skb->len < len) {
+			ret = -EINVAL;
+			goto out;
+		}
 
 		switch (le32_to_cpu(tlv->type)) {
 		case MT_NIC_CAP_6G:
+			if (len < sizeof(skb->data[0])) {
+				ret = -EINVAL;
+				goto out;
+			}
 			phy->cap.has_6ghz = skb->data[0];
 			break;
 		case MT_NIC_CAP_MAC_ADDR:
+			if (len < ETH_ALEN) {
+				ret = -EINVAL;
+				goto out;
+			}
 			memcpy(phy->macaddr, (void *)skb->data, ETH_ALEN);
 			break;
 		case MT_NIC_CAP_PHY:
+			if (len < sizeof(struct mt7921_phy_cap)) {
+				ret = -EINVAL;
+				goto out;
+			}
 			mt7921_mcu_parse_phy_cap(phy->dev, skb);
 			break;
 		case MT_NIC_CAP_TX_RESOURCE:
-			if (mt76_is_sdio(phy->dev))
+			if (mt76_is_sdio(phy->dev)) {
+				if (len < sizeof(struct mt7921_tx_resource)) {
+					ret = -EINVAL;
+					goto out;
+				}
 				mt7921_mcu_parse_tx_resource(phy->dev,
 							     skb);
+			}
 			break;
 		case MT_NIC_CAP_CHIP_CAP:
+			if (len < sizeof(mphy->chip_cap)) {
+				ret = -EINVAL;
+				goto out;
+			}
 			memcpy(&mphy->chip_cap, (void *)skb->data, sizeof(u64));
 			break;
 		default:

base-commit: 08dbfad3f5040f5bdb6c529da20d6d4e81fefd72
-- 
2.50.1