From: Yevgeny Kliteynik <kliteyn@nvidia.com>
Date: Wed, 3 Nov 2021 17:51:03 +0200
Subject: net/mlx5: DR, Fix check for unsupported fields in match param
Patch-mainline: v5.16-rc2
Git-commit: 455832d49666e1765acf812be79710b9f84a8cbf
References: jsc#SLE-19253

The existing loop doesn't cast the buffer while scanning it, which
results in out-of-bounds read and failure to create the matcher.

Fixes: 941f19798a11 ("net/mlx5: DR, Add check for unsupported fields in match param")
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c |   11 +++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c
@@ -924,11 +924,12 @@ static int dr_matcher_init(struct mlx5dr
 
 	/* Check that all mask data was consumed */
 	for (i = 0; i < consumed_mask.match_sz; i++) {
-		if (consumed_mask.match_buf[i]) {
-			mlx5dr_dbg(dmn, "Match param mask contains unsupported parameters\n");
-			ret = -EOPNOTSUPP;
-			goto free_consumed_mask;
-		}
+		if (!((u8 *)consumed_mask.match_buf)[i])
+			continue;
+
+		mlx5dr_dbg(dmn, "Match param mask contains unsupported parameters\n");
+		ret = -EOPNOTSUPP;
+		goto free_consumed_mask;
 	}
 
 	ret =  0;