From nobody Fri Sep 5 20:12:17 2025 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 7E60AC38159 for ; Tue, 23 Aug 2022 11:42:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358598AbiHWLmJ (ORCPT ); Tue, 23 Aug 2022 07:42:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358070AbiHWLgq (ORCPT ); Tue, 23 Aug 2022 07:36:46 -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 50A3776973; Tue, 23 Aug 2022 02:27:52 -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 E253CB81C98; Tue, 23 Aug 2022 09:27:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34F86C433B5; Tue, 23 Aug 2022 09:27:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661246867; bh=JKS/wh036ZMy+NNFjEtQnsz40COVFi65ZJtIo5klez8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R8edEF4gKCbOAS60CcTyTeiZ5m+VRNu0xkB2aW/PM5i0iS7GonYaspsaHcxjFdLp0 DEE/VYrHuqxSljYZsv6p4oxAoFXcY44mDfsk7Jkn1OH1BdJsjwV3dED4NbqHqOc4mx cqUqG3yHLqpeYGe+VSrb0kw7PBd1FVmzcXAtwinw= 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 5.4 246/389] video: fbdev: arkfb: Check the size of screen before memset_io() Date: Tue, 23 Aug 2022 10:25:24 +0200 Message-Id: <20220823080125.846934036@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@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 96b550971c65d54d64728d8ba973487878a06454 ] In the function arkfb_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: [ 659.399066] BUG: unable to handle page fault for address: ffffc900030000= 00 [ 659.399077] #PF: supervisor write access in kernel mode [ 659.399079] #PF: error_code(0x0002) - not-present page [ 659.399094] RIP: 0010:memset_orig+0x33/0xb0 [ 659.399116] Call Trace: [ 659.399122] arkfb_set_par+0x143f/0x24c0 [ 659.399130] fb_set_var+0x604/0xeb0 [ 659.399161] do_fb_ioctl+0x234/0x670 [ 659.399189] fb_ioctl+0xdd/0x130 Fix the this by checking the value of 'screen_size' before memset_io(). Fixes: 681e14730c73 ("arkfb: new framebuffer driver for ARK Logic cards") Signed-off-by: Zheyu Ma Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/arkfb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c index 311f7ea57625..6b1ad19b8db4 100644 --- a/drivers/video/fbdev/arkfb.c +++ b/drivers/video/fbdev/arkfb.c @@ -794,6 +794,8 @@ static int arkfb_set_par(struct fb_info *info) value =3D ((value * hmul / hdiv) / 8) - 5; vga_wcrt(par->state.vgabase, 0x42, (value + 1) / 2); =20 + if (screen_size > info->screen_size) + screen_size =3D info->screen_size; memset_io(info->screen_base, 0x00, screen_size); /* Device and screen back on */ svga_wcrt_mask(par->state.vgabase, 0x17, 0x80, 0x80); --=20 2.35.1