On 27/02/2020 11:46, Daniel Thompson wrote:
On Wed, Feb 26, 2020 at 07:58:26PM +0000, Colin King wrote:
From: Colin Ian King colin.king@canonical.com
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@canonical.com
V2: fix typo in commit subject line
Isn't the correct spelling "ensure"?
It is. V1 is correct after all. Doh.
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]);This look still looks buggy to me (so I'd second Walter's request to change it to a for loop). If the code genuinely does not contain a bug then it probably needs a prominent comment explaining why it is correct not to honour sources[0]!
Daniel.