[PATCH 4.15 019/122] mmc: dw_mmc-k3: Fix out-of-bounds access through DT alias

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

commit 325501d9360eb42c7c51e6daa0d733844c1e790b upstream.

The hs_timing_cfg[] array is indexed using a value derived from the
"mshcN" alias in DT, which may lead to an out-of-bounds access.

Fix this by adding a range check.

Fixes: 361c7fe9b02eee7e ("mmc: dw_mmc-k3: add sd support for hi3660")
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mmc/host/dw_mmc-k3.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/mmc/host/dw_mmc-k3.c
+++ b/drivers/mmc/host/dw_mmc-k3.c
@@ -135,6 +135,9 @@ static int dw_mci_hi6220_parse_dt(struct
 	if (priv->ctrl_id < 0)
 		priv->ctrl_id = 0;
 
+	if (priv->ctrl_id >= TIMING_MODE)
+		return -EINVAL;
+
 	host->priv = priv;
 	return 0;
 }