net/mlx5: DR, Fix check for unsupported fields in match param

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: 941f1979 ("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>

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c

@@ -924,11 +924,12 @@ static int dr_matcher_init(struct mlx5dr_matcher *matcher,
 
 	/* 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;