[PATCH 03/10] wifi: mt76: mt7915: validate MCU response lengths

[Jiale Yao <yaojiale02@163.com>]

The MCU response parser accesses receive descriptor fields and some
command payloads without checking their lengths. A truncated firmware
response can therefore cause an out-of-bounds read.

Validate the descriptor and the patch semaphore and thermal payloads
before accessing them.

Fixes: e57b7901469f ("mt76: add mac80211 driver for MT7915 PCIe-based chipsets")
Signed-off-by: Jiale Yao <yaojiale02@163.com>
---
 drivers/net/wireless/mediatek/mt76/mt7915/mcu.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
index 5bfe0366562f..3643906cbdf2 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -174,6 +174,11 @@ mt7915_mcu_parse_response(struct mt76_dev *mdev, int cmd,
 
 		return -ETIMEDOUT;
 	}
+	if (cmd == MCU_CMD(PATCH_SEM_CONTROL) &&
+	    skb->len < sizeof(*rxd) - 4 + sizeof(u8))
+		return -EINVAL;
+	if (cmd != MCU_CMD(PATCH_SEM_CONTROL) && skb->len < sizeof(*rxd))
+		return -EINVAL;
 
 	rxd = (struct mt76_connac2_mcu_rxd *)skb->data;
 	if (seq != rxd->seq &&
@@ -185,6 +190,9 @@ mt7915_mcu_parse_response(struct mt76_dev *mdev, int cmd,
 		skb_pull(skb, sizeof(*rxd) - 4);
 		ret = *skb->data;
 	} else if (cmd == MCU_EXT_CMD(THERMAL_CTRL)) {
+		if (skb->len < sizeof(*rxd) + 4 + sizeof(__le32))
+			return -EINVAL;
+
 		skb_pull(skb, sizeof(*rxd) + 4);
 		ret = le32_to_cpu(*(__le32 *)skb->data);
 	} else {
-- 
2.34.1