Commit c05b21eb authored by Marijn Suijten's avatar Marijn Suijten Committed by Lee Jones
Browse files

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: 775d2ffb ("backlight: qcom-wled: Restructure the driver for WLED3")
Signed-off-by: default avatarMarijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20211115203459.1634079-2-marijn.suijten@somainline.org
parent 6202b5de

drivers/video/backlight/qcom-wled.c

+17 −1
Original line number Diff line number Diff line
@@ -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;

}