From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59C57C61DA4 for ; Thu, 9 Mar 2023 07:55:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229716AbjCIHzr (ORCPT ); Thu, 9 Mar 2023 02:55:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230116AbjCIHy3 (ORCPT ); Thu, 9 Mar 2023 02:54:29 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E42BDB4BA; Wed, 8 Mar 2023 23:54:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678348446; x=1709884446; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=kfBBH9S/jBmS2pos8qoUcFdaqbPQy+BVbUPg/4bsR0Y=; b=PVESUZ48D18VzlMWr5uBvXbw7qe7zvYsUgCHfTvykQBlcT1E1M6b3u7W oD3KaDUxhohsvyngerEfDDZybAoBfX56ZtsNqjx87DHPSrd+db5locyNV WQKHej9eQ753wu3J07YwB7XgSUZPaBSiFyZR9ky4U2MQjjjLhRoJidFUU 4iMeNM0U4OoK3hG2KriihJCCEpSlfHB9szEEB134tJbikwSyzMkoT6OwD p12+9aeu9XPTgp3xyRtc7852sS6uw9gVmq+VVJkf9Ai5RmiODQoqBNbeu Nn0LnmIgiJqvxX7ROLaAYYEqQE6nupRcN4a3+0HiG5Z5ZgB3a5ErG14cD Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10643"; a="324701592" X-IronPort-AV: E=Sophos;i="5.98,245,1673942400"; d="scan'208";a="324701592" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2023 23:54:05 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10643"; a="1006635679" X-IronPort-AV: E=Sophos;i="5.98,245,1673942400"; d="scan'208";a="1006635679" Received: from unknown (HELO localhost) ([10.237.66.145]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2023 23:54:03 -0800 From: Jani Nikula To: Helge Deller , harperchen Cc: linux-fbdev@vger.kernel.org, javierm@redhat.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, wsa+renesas@sang-engineering.com, tzimmermann@suse.de Subject: Re: [PATCH] fbdev: tgafb: Fix potential divide by zero In-Reply-To: <123a52d8-baf0-e32b-3262-1e8619b1c3ad@gmx.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20230307130856.2295182-1-harperchen1110@gmail.com> <123a52d8-baf0-e32b-3262-1e8619b1c3ad@gmx.de> Date: Thu, 09 Mar 2023 09:53:56 +0200 Message-ID: <87cz5ibbsb.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Wed, 08 Mar 2023, Helge Deller wrote: > On 3/7/23 14:08, harperchen wrote: >> fb_set_var would by called when user invokes ioctl with cmd >> FBIOPUT_VSCREENINFO. User-provided data would finally reach >> tgafb_check_var. In case var->pixclock is assigned to zero, >> divide by zero would occur when checking whether reciprocal >> of var->pixclock is too high. >> >> Similar crashes have happened in other fbdev drivers. There >> is no check and modification on var->pixclock along the call >> chain to tgafb_check_var. We believe it could also be triggered >> in driver tgafb from user site. >> >> Signed-off-by: harperchen > > Could you provide a real name? > Otherwise applied to fbdev git tree. See commit d4563201f33a ("Documentation: simplify and clarify DCO contribution example language"). BR, Jani. > > Thanks! > Helge > >> --- >> drivers/video/fbdev/tgafb.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/video/fbdev/tgafb.c b/drivers/video/fbdev/tgafb.c >> index 14d37c49633c..b44004880f0d 100644 >> --- a/drivers/video/fbdev/tgafb.c >> +++ b/drivers/video/fbdev/tgafb.c >> @@ -173,6 +173,9 @@ tgafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) >> { >> struct tga_par *par = (struct tga_par *)info->par; >> >> + if (!var->pixclock) >> + return -EINVAL; >> + >> if (par->tga_type == TGA_TYPE_8PLANE) { >> if (var->bits_per_pixel != 8) >> return -EINVAL; > -- Jani Nikula, Intel Open Source Graphics Center