On 2021-10-05 10:14:52, Daniel Thompson wrote:
On Mon, Oct 04, 2021 at 09:27:35PM +0200, Marijn Suijten wrote:
The strings passed in DT may possibly cause out-of-bounds register accesses and should be validated before use.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3")
The first half of this patch actually fixes patch 1 from this patch set. It would be better to move that code there.
It only helps guarding against a maximum of 3 leds for WLED3, while using string_len instead of an unintentional sizeof(u32) (resulting in a fixed size of 4) is a different issue requiring a separate patch to fix.
Would it help to reorder this patch before 1/10, and mention in patch 1/10 (then 2/10) that, besides properly using string_len instead of hardcoded 4 (which causes wrong reads from DT on top of this), it relies on the previous patch to prevent against an array longer than 3 for WLED3?
- Marijn
Daniel.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 29910e603c42..27e8949c7922 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1526,6 +1526,12 @@ static int wled_configure(struct wled *wled) "qcom,enabled-strings", sizeof(u32)); 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;}- rc = of_property_read_u32_array(dev->of_node, "qcom,enabled-strings", wled->cfg.enabled_strings,
@@ -1537,6 +1543,14 @@ static int wled_configure(struct wled *wled) return -EINVAL; }
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;}}- cfg->num_strings = string_len; }
-- 2.33.0