From patchwork Thu Mar 8 07:31:59 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 882986 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3zxj0K1X58z9scq for ; Thu, 8 Mar 2018 18:32:47 +1100 (AEDT) Received: from localhost ([::1]:37274 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etq2d-000787-Ks for incoming@patchwork.ozlabs.org; Thu, 08 Mar 2018 02:32:43 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56492) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etq2G-00077z-JQ for qemu-devel@nongnu.org; Thu, 08 Mar 2018 02:32:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1etq2D-0002Ou-Fz for qemu-devel@nongnu.org; Thu, 08 Mar 2018 02:32:20 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38230 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1etq2D-0002Om-Br for qemu-devel@nongnu.org; Thu, 08 Mar 2018 02:32:17 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E6FF94023BB3; Thu, 8 Mar 2018 07:32:04 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-39.ams2.redhat.com [10.36.116.39]) by smtp.corp.redhat.com (Postfix) with ESMTP id 950EB2026E03; Thu, 8 Mar 2018 07:32:00 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id B7A0717513; Thu, 8 Mar 2018 08:31:59 +0100 (CET) From: Gerd Hoffmann To: qemu-devel@nongnu.org Date: Thu, 8 Mar 2018 08:31:59 +0100 Message-Id: <20180308073159.1068-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Thu, 08 Mar 2018 07:32:06 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Thu, 08 Mar 2018 07:32:06 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'kraxel@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH] vga: fix region calculation X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ross Lagerwall , Gerd Hoffmann , P J P Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Typically the scanline length and the line offset are identical. But case they are not our calculation for region_end is incorrect. Using line_offset is fine for all scanlines, except the last one where we have to use the actual scanline length. Fixes: CVE-2018- Cc: P J P Cc: Ross Lagerwall Signed-off-by: Gerd Hoffmann Reviewed-by: Prasad J Pandit Tested-by: Ross Lagerwall --- hw/display/vga.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/display/vga.c b/hw/display/vga.c index 28f298b342..72181330b8 100644 --- a/hw/display/vga.c +++ b/hw/display/vga.c @@ -1483,6 +1483,8 @@ static void vga_draw_graphic(VGACommonState *s, int full_update) region_start = (s->start_addr * 4); region_end = region_start + (ram_addr_t)s->line_offset * height; + region_end += width * s->get_bpp(s) / 8; /* scanline length */ + region_end -= s->line_offset; if (region_end > s->vbe_size) { /* wraps around (can happen with cirrus vbe modes) */ region_start = 0;