[PATCH] wifi: mt76: mt7615: validate MCU response lengths

[Pengpeng Hou]

mt7615_mcu_parse_response() reads the common response header before
checking its size and then consumes command-specific fields after unchecked
skb_pull() calls. A short firmware response can therefore be read beyond
its current extent.

Validate the common header and each command-specific payload before reading
it.

Fixes: 0e6a29e477f3 ("mt76: mt7615: add support to read temperature from mcu")
Signed-off-by: Pengpeng Hou <pengpeng at iscas.ac.cn>
---
 drivers/net/wireless/mediatek/mt76/mt7615/mcu.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
index ff57ede87f717..084949dd3e94e 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mcu.c
@@ -143,18 +143,26 @@ int mt7615_mcu_parse_response(struct mt76_dev *mdev, int cmd,
 			cmd, seq);
 		return -ETIMEDOUT;
 	}
+	if (skb->len < sizeof(*rxd))
+		return -EMSGSIZE;
 
 	rxd = (struct mt7615_mcu_rxd *)skb->data;
 	if (seq != rxd->seq)
 		return -EAGAIN;
 
 	if (cmd == MCU_CMD(PATCH_SEM_CONTROL)) {
+		if (skb->len < sizeof(*rxd) - 4 + sizeof(skb->data[0]))
+			return -EMSGSIZE;
 		skb_pull(skb, sizeof(*rxd) - 4);
 		ret = *skb->data;
 	} else if (cmd == MCU_EXT_CMD(THERMAL_CTRL)) {
+		if (skb->len < sizeof(*rxd) + sizeof(__le32))
+			return -EMSGSIZE;
 		skb_pull(skb, sizeof(*rxd));
 		ret = le32_to_cpu(*(__le32 *)skb->data);
 	} else if (cmd == MCU_EXT_QUERY(RF_REG_ACCESS)) {
+		if (skb->len < sizeof(*rxd) + 8 + sizeof(__le32))
+			return -EMSGSIZE;
 		skb_pull(skb, sizeof(*rxd));
 		ret = le32_to_cpu(*(__le32 *)&skb->data[8]);
 	} else if (cmd == MCU_UNI_CMD(DEV_INFO_UPDATE) ||
@@ -165,12 +173,16 @@ int mt7615_mcu_parse_response(struct mt76_dev *mdev, int cmd,
 		   cmd == MCU_UNI_CMD(SUSPEND)) {
 		struct mt76_connac_mcu_uni_event *event;
 
+		if (skb->len < sizeof(*rxd) + sizeof(*event))
+			return -EMSGSIZE;
 		skb_pull(skb, sizeof(*rxd));
 		event = (struct mt76_connac_mcu_uni_event *)skb->data;
 		ret = le32_to_cpu(event->status);
 	} else if (cmd == MCU_CE_QUERY(REG_READ)) {
 		struct mt76_connac_mcu_reg_event *event;
 
+		if (skb->len < sizeof(*rxd) + sizeof(*event))
+			return -EMSGSIZE;
 		skb_pull(skb, sizeof(*rxd));
 		event = (struct mt76_connac_mcu_reg_event *)skb->data;
 		ret = (int)le32_to_cpu(event->val);

base-commit: 08dbfad3f5040f5bdb6c529da20d6d4e81fefd72
-- 
2.50.1