[PATCH 6.19 444/844] ntb: ntb_hw_switchtec: Fix array-index-out-of-bounds access

[Sasha Levin]

From: Maciej Grochowski <Maciej.Grochowski@xxxxxxxx>

[ Upstream commit c8ba7ad2cc1c7b90570aa347b8ebbe279f1eface ]

Number of MW LUTs depends on NTB configuration and can be set to MAX_MWS,
This patch protects against invalid index out of bounds access to mw_sizes
When invalid access print message to user that configuration is not valid.

Signed-off-by: Maciej Grochowski <Maciej.Grochowski@xxxxxxxx>
Signed-off-by: Jon Mason <jdmason@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
index f851397b65d6e..f15ebab138144 100644
--- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
+++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
@@ -1314,6 +1314,12 @@ static void switchtec_ntb_init_shared(struct switchtec_ntb *sndev)
 	for (i = 0; i < sndev->nr_lut_mw; i++) {
 		int idx = sndev->nr_direct_mw + i;
 
+		if (idx >= MAX_MWS) {
+			dev_err(&sndev->stdev->dev,
+				"Total number of MW cannot be bigger than %d", MAX_MWS);
+			break;
+		}
+
 		sndev->self_shared->mw_sizes[idx] = LUT_SIZE;
 	}
 }
-- 
2.51.0