From nobody Tue Nov 4 13:11:27 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1504272289542388.41012622009976; Fri, 1 Sep 2017 06:24:49 -0700 (PDT) Received: from localhost ([::1]:40034 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dnlwG-00019j-Bb for importer@patchew.org; Fri, 01 Sep 2017 09:24:48 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54738) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dnlWB-0001x1-6i for qemu-devel@nongnu.org; Fri, 01 Sep 2017 08:57:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dnlW6-0007oi-DK for qemu-devel@nongnu.org; Fri, 01 Sep 2017 08:57:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49048) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dnlW6-0007oI-77 for qemu-devel@nongnu.org; Fri, 01 Sep 2017 08:57:46 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2E8A44E4C2 for ; Fri, 1 Sep 2017 12:57:45 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-70.ams2.redhat.com [10.36.116.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 793967B0E5; Fri, 1 Sep 2017 12:57:44 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 560BB16A896; Fri, 1 Sep 2017 14:57:42 +0200 (CEST) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2E8A44E4C2 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=kraxel@redhat.com From: Gerd Hoffmann To: qemu-devel@nongnu.org Date: Fri, 1 Sep 2017 14:57:38 +0200 Message-Id: <20170901125742.4249-2-kraxel@redhat.com> In-Reply-To: <20170901125742.4249-1-kraxel@redhat.com> References: <20170901125742.4249-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 01 Sep 2017 12:57:45 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 1/5] vga: fix display update region calculation (split screen) 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: Gerd Hoffmann , P J P Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" vga display update mis-calculated the region for the dirty bitmap snapshot in case split screen mode is used. This can trigger an assert in cpu_physical_memory_snapshot_get_dirty(). Impact: DoS for privileged guest users. Fixes: CVE-2017-13673 Fixes: fec5e8c92becad223df9d972770522f64aafdb72 Cc: P J P Reported-by: David Buchanan Signed-off-by: Gerd Hoffmann Message-id: 20170828123307.15392-1-kraxel@redhat.com --- hw/display/vga.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/hw/display/vga.c b/hw/display/vga.c index 3433102ef3..ad7a46563c 100644 --- a/hw/display/vga.c +++ b/hw/display/vga.c @@ -1628,9 +1628,15 @@ static void vga_draw_graphic(VGACommonState *s, int = full_update) y1 =3D 0; =20 if (!full_update) { + ram_addr_t region_start =3D addr1; + ram_addr_t region_end =3D addr1 + line_offset * height; vga_sync_dirty_bitmap(s); - snap =3D memory_region_snapshot_and_clear_dirty(&s->vram, addr1, - line_offset * height, + if (s->line_compare < height) { + /* split screen mode */ + region_start =3D 0; + } + snap =3D memory_region_snapshot_and_clear_dirty(&s->vram, region_s= tart, + region_end - region_= start, DIRTY_MEMORY_VGA); } =20 --=20 2.9.3