From nobody Sat Feb 7 21:56:03 2026 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 D6687C32792 for ; Tue, 23 Aug 2022 10:05:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352238AbiHWKFB (ORCPT ); Tue, 23 Aug 2022 06:05:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351893AbiHWKAq (ORCPT ); Tue, 23 Aug 2022 06:00:46 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A741B219C; Tue, 23 Aug 2022 01:48:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 549C6B81C39; Tue, 23 Aug 2022 08:48:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8874C433D6; Tue, 23 Aug 2022 08:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661244500; bh=dS14W8ecUphTKxvCQBorbBcTsP8koOnv//b1T3gJMZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1oeYgn0CguyaJHkL3MYF8Ny/yxeUCuz+bS6xJDMf8uip1R0rYdt/ddl408rVhunSN 1tjw5HFJxJCXB9GNE3/JIytXTkSFoeHZ9Y9A5CBkoJSTDyWDJQR2I2kXMoEoLx8ykg OwZvKkQ+xGvi0RWRN0oUZ1NgJaEhvwElF06wKlV4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zheyu Ma , Helge Deller , Sasha Levin Subject: [PATCH 4.14 146/229] video: fbdev: vt8623fb: Check the size of screen before memset_io() Date: Tue, 23 Aug 2022 10:25:07 +0200 Message-Id: <20220823080058.894853891@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080053.202747790@linuxfoundation.org> References: <20220823080053.202747790@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Zheyu Ma [ Upstream commit ec0754c60217248fa77cc9005d66b2b55200ac06 ] In the function vt8623fb_set_par(), the value of 'screen_size' is calculated by the user input. If the user provides the improper value, the value of 'screen_size' may larger than 'info->screen_size', which may cause the following bug: [ 583.339036] BUG: unable to handle page fault for address: ffffc900050000= 00 [ 583.339049] #PF: supervisor write access in kernel mode [ 583.339052] #PF: error_code(0x0002) - not-present page [ 583.339074] RIP: 0010:memset_orig+0x33/0xb0 [ 583.339110] Call Trace: [ 583.339118] vt8623fb_set_par+0x11cd/0x21e0 [ 583.339146] fb_set_var+0x604/0xeb0 [ 583.339181] do_fb_ioctl+0x234/0x670 [ 583.339209] fb_ioctl+0xdd/0x130 Fix the this by checking the value of 'screen_size' before memset_io(). Fixes: 558b7bd86c32 ("vt8623fb: new framebuffer driver for VIA VT8623") Signed-off-by: Zheyu Ma Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/vt8623fb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/vt8623fb.c b/drivers/video/fbdev/vt8623fb.c index 5cac871db3ee..cbae9c510092 100644 --- a/drivers/video/fbdev/vt8623fb.c +++ b/drivers/video/fbdev/vt8623fb.c @@ -504,6 +504,8 @@ static int vt8623fb_set_par(struct fb_info *info) (info->var.vmode & FB_VMODE_DOUBLE) ? 2 : 1, 1, 1, info->node); =20 + if (screen_size > info->screen_size) + screen_size =3D info->screen_size; memset_io(info->screen_base, 0x00, screen_size); =20 /* Device and screen back on */ --=20 2.35.1