From mboxrd@z Thu Jan 1 00:00:00 1970 From: Walter Harms Date: Thu, 27 Feb 2020 11:15:55 +0000 Subject: AW: [PATCH][V2] backlight: sky81452: insure while loop does not allow negative array indexing Message-Id: List-Id: References: <20200226195826.6567-1-colin.king@canonical.com> In-Reply-To: <20200226195826.6567-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Colin King , Lee Jones , Daniel Thompson , Jingoo Han , Bartlomiej Zolnierkiewicz , Gyungoh Yoo , Bryan Wu , "dri-devel@lists.freedesktop.org" , "linux-fbdev@vger.kernel.org" Cc: "kernel-janitors@vger.kernel.org" , "linux-kernel@vger.kernel.org" hi all, i would suggest converting this in to a more common for() loop. Programmers are bad in counting backwards. that kind of bug is common. re, wh ________________________________________ Von: kernel-janitors-owner@vger.kernel.org im Auftrag von Colin King Gesendet: Mittwoch, 26. Februar 2020 20:58 An: Lee Jones; Daniel Thompson; Jingoo Han; Bartlomiej Zolnierkiewicz; Gyungoh Yoo; Bryan Wu; dri-devel@lists.freedesktop.org; linux-fbdev@vger.kernel.org Cc: kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org Betreff: [PATCH][V2] backlight: sky81452: insure while loop does not allow negative array indexing From: Colin Ian King 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 --- V2: fix typo in commit subject line --- 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]); int i; for(i=0;ienable |= (1 << sources[i]); } -- 2.25.0