From nobody Sat May 4 22:48:45 2024 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 1503566521062124.84623029993247; Thu, 24 Aug 2017 02:22:01 -0700 (PDT) Received: from localhost ([::1]:47397 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dkoKt-0006Ii-PJ for importer@patchew.org; Thu, 24 Aug 2017 05:21:59 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45565) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dkoJf-0005V1-4t for qemu-devel@nongnu.org; Thu, 24 Aug 2017 05:20:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dkoJa-0003Xv-2r for qemu-devel@nongnu.org; Thu, 24 Aug 2017 05:20:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34602) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dkoJZ-0003Xa-TE for qemu-devel@nongnu.org; Thu, 24 Aug 2017 05:20:38 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C2AAB4E33B; Thu, 24 Aug 2017 09:20:36 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-116-82.ams2.redhat.com [10.36.116.82]) by smtp.corp.redhat.com (Postfix) with ESMTP id 168626A916; Thu, 24 Aug 2017 09:20:34 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 4858C3FBB7; Thu, 24 Aug 2017 11:20:33 +0200 (CEST) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C2AAB4E33B 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: Thu, 24 Aug 2017 11:20:33 +0200 Message-Id: <20170824092033.18130-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Thu, 24 Aug 2017 09:20:36 +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] [PATCH] 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 , d@vidbuchanan.co.uk, 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 priviledged guest users. Fixes: CVE-2017-xxxx Fixes: fec5e8c92becad223df9d972770522f64aafdb72 Cc: P J P Reported-by: David Buchanan Signed-off-by: Gerd Hoffmann --- 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 63421f9ee8..ab33668402 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