[PATCH mt76-next 03/11] wifi: mt76: mt7925: validate NIC capability TLV lengths

[Felix Fietkau <nbd@nbd.name>]

mt7925_mcu_get_nic_capability() checks that each TLV fits in the
response, but not that the TLV is long enough for its own header or for
the fields read from it. A short chip capability TLV at the end of the
response causes an out-of-bounds read of its eight-byte value. A TLV
length below the header size makes the loop parse overlapping TLVs.

Stop at a TLV shorter than its header, and skip a TLV that is too short
for the fields its parser reads, like mt7921 does.

Fixes: c948b5da6bbe ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
Fixes: 86c051f2c418 ("wifi: mt76: mt7925: enabling MLO when the firmware supports it")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 .../net/wireless/mediatek/mt76/mt7925/mcu.c   | 29 +++++++++++++------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
index f299a3379adb..d26b90ab5e60 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
@@ -1058,7 +1058,7 @@ int mt7925_mcu_get_temperature(struct mt792x_phy *phy)
 }
 
 static void
-mt7925_mcu_parse_phy_cap(struct mt792x_dev *dev, char *data)
+mt7925_mcu_parse_phy_cap(struct mt792x_dev *dev, char *data, int len)
 {
 	struct mt76_phy *mphy = &dev->mt76.phy;
 	struct mt76_dev *mdev = mphy->dev;
@@ -1082,6 +1082,9 @@ mt7925_mcu_parse_phy_cap(struct mt792x_dev *dev, char *data)
 		WF0_5G
 	};
 
+	if (len < offsetofend(struct mt7925_mcu_phy_cap, hw_path))
+		return;
+
 	cap = (struct mt7925_mcu_phy_cap *)data;
 
 	mdev->phy.antenna_mask = BIT(cap->nss) - 1;
@@ -1091,7 +1094,7 @@ mt7925_mcu_parse_phy_cap(struct mt792x_dev *dev, char *data)
 }
 
 static void
-mt7925_mcu_parse_eml_cap(struct mt792x_dev *dev, char *data)
+mt7925_mcu_parse_eml_cap(struct mt792x_dev *dev, char *data, int len)
 {
 	struct mt7925_mcu_eml_cap {
 		u8 rsv[4];
@@ -1099,6 +1102,9 @@ mt7925_mcu_parse_eml_cap(struct mt792x_dev *dev, char *data)
 		u8 rsv2[6];
 	} __packed * cap;
 
+	if (len < offsetofend(struct mt7925_mcu_eml_cap, eml_cap))
+		return;
+
 	cap = (struct mt7925_mcu_eml_cap *)data;
 
 	dev->phy.eml_cap = le16_to_cpu(cap->eml_cap);
@@ -1139,30 +1145,35 @@ mt7925_mcu_get_nic_capability(struct mt792x_dev *dev)
 
 	for (i = 0; i < le16_to_cpu(hdr->n_element); i++) {
 		struct tlv *tlv = (struct tlv *)skb->data;
-		int len;
+		int len, data_len;
 
 		if (skb->len < sizeof(*tlv))
 			break;
 
 		len = le16_to_cpu(tlv->len);
-		if (skb->len < len)
+		if (len < sizeof(*tlv) || skb->len < len)
 			break;
 
+		data_len = len - sizeof(*tlv);
 		switch (le16_to_cpu(tlv->tag)) {
 		case MT_NIC_CAP_6G:
-			mphy->cap.has_6ghz = !!tlv->data[0];
+			if (data_len)
+				mphy->cap.has_6ghz = !!tlv->data[0];
 			break;
 		case MT_NIC_CAP_MAC_ADDR:
-			memcpy(mphy->macaddr, (void *)tlv->data, ETH_ALEN);
+			if (data_len >= ETH_ALEN)
+				memcpy(mphy->macaddr, (void *)tlv->data, ETH_ALEN);
 			break;
 		case MT_NIC_CAP_PHY:
-			mt7925_mcu_parse_phy_cap(dev, tlv->data);
+			mt7925_mcu_parse_phy_cap(dev, tlv->data, data_len);
 			break;
 		case MT_NIC_CAP_CHIP_CAP:
-			dev->phy.chip_cap = le64_to_cpu(*(__le64 *)tlv->data);
+			if (data_len >= sizeof(__le64))
+				dev->phy.chip_cap =
+					le64_to_cpu(*(__le64 *)tlv->data);
 			break;
 		case MT_NIC_CAP_EML_CAP:
-			mt7925_mcu_parse_eml_cap(dev, tlv->data);
+			mt7925_mcu_parse_eml_cap(dev, tlv->data, data_len);
 			break;
 		default:
 			break;
-- 
2.47.3