backlight: qcom-wled: Validate enabled string indices in DT

The strings passed in DT may possibly cause out-of-bounds register accesses and should be validated before use. Fixes: 775d2ff ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten <[email protected]> Reviewed-by: AngeloGioacchino Del Regno <[email protected]> Reviewed-by: Daniel Thompson <[email protected]> Signed-off-by: Lee Jones <[email protected]> Link: https://lore.kernel.org/r/[email protected]
archeYR · Dec 22, 2021 · c05b21e · c05b21e
1 parent 6202b5d
commit c05b21e
Showing 1 changed file with 17 additions and 1 deletion.
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
@@ -1528,12 +1528,28 @@ static int wled_configure(struct wled *wled)
 	string_len = of_property_count_elems_of_size(dev->of_node,
 						     "qcom,enabled-strings",
 						     sizeof(u32));
-	if (string_len > 0)
+	if (string_len > 0) {
+		if (string_len > wled->max_string_count) {
+			dev_err(dev, "Cannot have more than %d strings\n",
+				wled->max_string_count);
+			return -EINVAL;
+		}
+
 		of_property_read_u32_array(dev->of_node,
 						"qcom,enabled-strings",
 						wled->cfg.enabled_strings,
 						sizeof(u32));
 
+		for (i = 0; i < string_len; ++i) {
+			if (wled->cfg.enabled_strings[i] >= wled->max_string_count) {
+				dev_err(dev,
+					"qcom,enabled-strings index %d at %d is out of bounds\n",
+					wled->cfg.enabled_strings[i], i);
+				return -EINVAL;
+			}
+		}
+	}
+
 	return 0;
 }