[PATCH] backlight: sky81452: unsure while loop does not allow negative array indexing

From: Colin King
Date: Wed Feb 26 2020 - 14:57:47 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

In the unlikely event that num_entry is zero, the while loop
pre-decrements num_entry to cause negative array indexing into the
array sources. Fix this by iterating only if num_entry >= 0.

Addresses-Coverity: ("Out-of-bounds read")
Fixes: f705806c9f35 ("backlight: Add support Skyworks SKY81452 backlight driver")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/video/backlight/sky81452-backlight.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/backlight/sky81452-backlight.c b/drivers/video/backlight/sky81452-backlight.c
index 2355f00f5773..f456930ce78e 100644
--- a/drivers/video/backlight/sky81452-backlight.c
+++ b/drivers/video/backlight/sky81452-backlight.c
@@ -200,7 +200,7 @@ static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
}

pdata->enable = 0;
- while (--num_entry)
+ while (--num_entry >= 0)
pdata->enable |= (1 << sources[num_entry]);
}

--
2.25.0