[PATCH 05/10] backlight: qcom-wled: Fix off-by-one maximum with default num_strings
From: Marijn Suijten <marijn.suijten@somainline.org>
Date: 2021-10-04 19:27:54
Also in:
dri-devel, linux-arm-msm, lkml, phone-devel
Subsystem:
arm/qualcomm mailing list, backlight class/subsystem, framebuffer layer, the rest · Maintainers:
Lee Jones, Daniel Thompson, Jingoo Han, Helge Deller, Linus Torvalds
When not specifying num-strings in the DT the default is used, but +1 is
added to it which turns wled3 into 4 and wled4/5 into 5 strings instead
of 3 and 4 respectively, causing out of bounds reads and register
read/writes. This +1 exists for a deficiency in the DT parsing code,
and is simply omitted entirely - solving this oob issue - by allowing
one extra iteration of the wled_var_cfg function parsing this particular
property.
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: AngeloGioacchino Del Regno <redacted>
---
drivers/video/backlight/qcom-wled.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index 27e8949c7922..66ce77ee3099 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c@@ -1255,17 +1255,17 @@ static const struct wled_var_cfg wled5_ovp_cfg = { static u32 wled3_num_strings_values_fn(u32 idx) { - return idx + 1; + return idx; } static const struct wled_var_cfg wled3_num_strings_cfg = { .fn = wled3_num_strings_values_fn, - .size = 3, + .size = 4, /* [0, 3] */ }; static const struct wled_var_cfg wled4_num_strings_cfg = { .fn = wled3_num_strings_values_fn, - .size = 4, + .size = 5, /* [0, 4] */ }; static u32 wled3_switch_freq_values_fn(u32 idx)
@@ -1520,8 +1520,6 @@ static int wled_configure(struct wled *wled) *bool_opts[i].val_ptr = true; } - cfg->num_strings = cfg->num_strings + 1; - string_len = of_property_count_elems_of_size(dev->of_node, "qcom,enabled-strings", sizeof(u32));
--
2.33.0