[PATCH] wifi: mt76: mt7925: validate CLC firmware records

[Laxman Acharya Padhya <acharyalaxman8848@gmail.com>]

The CLC region is supplied by firmware, but the loader trusts the region
count and each record length. A malformed image can make the region table
pointer precede the firmware buffer, make the record loop fail to advance,
or index phy->clc past its end. Validate the table and record bounds
before dereferencing or copying.

Fixes: c948b5da6bbe ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
Cc: stable@vger.kernel.org
Signed-off-by: Laxman Acharya Padhya <acharyalaxman8848@gmail.com>
---
 .../net/wireless/mediatek/mt76/mt7925/mcu.c   | 32 ++++++++++++++-----
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
index e94fa544ff20..76e30bf4ce0f 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
@@ -803,8 +803,9 @@ static int mt7925_load_clc(struct mt792x_dev *dev, const char *fw_name)
 	struct mt76_dev *mdev = &dev->mt76;
 	struct mt792x_phy *phy = &dev->phy;
 	const struct firmware *fw;
+	size_t clc_len, fw_data_len, len, offset = 0;
 	u8 *clc_base = NULL, hw_encap = 0;
-	int ret, i, len, offset = 0;
+	int ret, i;
 
 	dev->phy.clc_chan_conf = 0xff;
 	dev->regd_user = false;
@@ -829,13 +830,21 @@ static int mt7925_load_clc(struct mt792x_dev *dev, const char *fw_name)
 	}
 
 	hdr = (const void *)(fw->data + fw->size - sizeof(*hdr));
+	if (hdr->n_region > (fw->size - sizeof(*hdr)) / sizeof(*region)) {
+		dev_err(mdev->dev, "Invalid firmware region table\n");
+		ret = -EINVAL;
+		goto out;
+	}
+	fw_data_len = fw->size - sizeof(*hdr) -
+		      hdr->n_region * sizeof(*region);
+
 	for (i = 0; i < hdr->n_region; i++) {
 		region = (const void *)((const u8 *)hdr -
 					(hdr->n_region - i) * sizeof(*region));
 		len = le32_to_cpu(region->len);
 
 		/* check if we have valid buffer size */
-		if (offset + len > fw->size) {
+		if (len > fw_data_len - offset) {
 			dev_err(mdev->dev, "Invalid firmware region\n");
 			ret = -EINVAL;
 			goto out;
@@ -852,11 +861,19 @@ static int mt7925_load_clc(struct mt792x_dev *dev, const char *fw_name)
 	if (!clc_base)
 		goto out;
 
-	for (offset = 0; offset < len; offset += le32_to_cpu(clc->len)) {
-		clc = (const struct mt7925_clc *)(clc_base + offset);
+	for (offset = 0; offset < len; offset += clc_len) {
+		if (len - offset < sizeof(*clc)) {
+			ret = -EINVAL;
+			goto out;
+		}
 
-		if (clc->idx >= ARRAY_SIZE(phy->clc))
-			break;
+		clc = (const struct mt7925_clc *)(clc_base + offset);
+		clc_len = le32_to_cpu(clc->len);
+		if (clc_len < sizeof(*clc) || clc_len > len - offset ||
+		    clc->idx >= ARRAY_SIZE(phy->clc)) {
+			ret = -EINVAL;
+			goto out;
+		}
 
 		/* do not init buf again if chip reset triggered */
 		if (phy->clc[clc->idx])
@@ -869,8 +886,7 @@ static int mt7925_load_clc(struct mt792x_dev *dev, const char *fw_name)
 			continue;
 
 		phy->clc[clc->idx] = devm_kmemdup(mdev->dev, clc,
-						  le32_to_cpu(clc->len),
-						  GFP_KERNEL);
+						  clc_len, GFP_KERNEL);
 
 		if (!phy->clc[clc->idx]) {
 			ret = -ENOMEM;
-- 
2.51.2