[PATCH] wifi: wfx: validate MIB read length before copying to caller

wfx_hif_read_mib() copies reply->length bytes from the firmware
response into the caller-provided buffer without checking that
reply->length does not exceed val_len. A firmware response with
a length field larger than expected causes a heap buffer overflow
when writing to the caller buffer.

Replace the dead -ENOMEM check with an active validation that
reply->length fits within val_len before the memcpy.

Fixes: 9bca45f3d692 ("staging: wfx: allow to send 802.11 frames")
Signed-off-by: Aamir Ahmed <redacted>
---
 drivers/net/wireless/silabs/wfx/hif_tx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/silabs/wfx/hif_tx.c b/drivers/net/wireless/silabs/wfx/hif_tx.c
index 9f403d275cb1..a6bc1c522e3c 100644
--- a/drivers/net/wireless/silabs/wfx/hif_tx.c
+++ b/drivers/net/wireless/silabs/wfx/hif_tx.c

@@ -207,9 +207,11 @@ int wfx_hif_read_mib(struct wfx_dev *wdev, int vif_id, u16 mib_id, void *val, si
 		dev_warn(wdev->dev, "%s: confirmation mismatch request\n", __func__);
 		ret = -EIO;
 	}
-	if (ret == -ENOMEM)
+	if (!ret && le16_to_cpu(reply->length) > val_len) {
 		dev_err(wdev->dev, "buffer is too small to receive %s (%zu < %d)\n",
 			wfx_get_mib_name(mib_id), val_len, le16_to_cpu(reply->length));
+		ret = -EINVAL;
+	}
 	if (!ret)
 		memcpy(val, &reply->mib_data, le16_to_cpu(reply->length));
 	else

-- 
2.43.0