From patchwork Wed Feb 26 19:58:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colin King X-Patchwork-Id: 11407119 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0894092A for ; Wed, 26 Feb 2020 19:58:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E55BD222C4 for ; Wed, 26 Feb 2020 19:58:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727306AbgBZT6c (ORCPT ); Wed, 26 Feb 2020 14:58:32 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:59020 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbgBZT6c (ORCPT ); Wed, 26 Feb 2020 14:58:32 -0500 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1j72p8-0000Jj-K4; Wed, 26 Feb 2020 19:58:26 +0000 From: Colin King To: 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 Subject: [PATCH][V2] backlight: sky81452: insure while loop does not allow negative array indexing Date: Wed, 26 Feb 2020 19:58:26 +0000 Message-Id: <20200226195826.6567-1-colin.king@canonical.com> X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org 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]); }