From patchwork Wed Mar 2 03:58:35 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Congyang X-Patchwork-Id: 85022 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 2A000B70D9 for ; Wed, 2 Mar 2011 15:01:50 +1100 (EST) Received: from localhost ([127.0.0.1]:33413 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PudFz-0001jv-Cw for incoming@patchwork.ozlabs.org; Tue, 01 Mar 2011 23:01:47 -0500 Received: from [140.186.70.92] (port=53081 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PudEA-0000eX-OO for qemu-devel@nongnu.org; Tue, 01 Mar 2011 22:59:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PudE9-0003kS-B2 for qemu-devel@nongnu.org; Tue, 01 Mar 2011 22:59:54 -0500 Received: from [222.73.24.84] (port=65061 helo=song.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PudE9-0003kF-0U for qemu-devel@nongnu.org; Tue, 01 Mar 2011 22:59:53 -0500 Received: from tang.cn.fujitsu.com (tang.cn.fujitsu.com [10.167.250.3]) by song.cn.fujitsu.com (Postfix) with ESMTP id E69D0170139; Wed, 2 Mar 2011 11:59:45 +0800 (CST) Received: from mailserver.fnst.cn.fujitus.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id p223rtQw032039; Wed, 2 Mar 2011 11:53:55 +0800 Received: from [10.167.225.226] ([10.167.225.226]) by mailserver.fnst.cn.fujitus.com (Lotus Domino Release 8.5.1FP4) with ESMTP id 2011030211583710-258256 ; Wed, 2 Mar 2011 11:58:37 +0800 Message-ID: <4D6DC06B.6070308@cn.fujitsu.com> Date: Wed, 02 Mar 2011 11:58:35 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: qemu-devel , Stefan Weil , Anthony Liguori , Corentin Chary References: <4D6DBDA4.3050909@cn.fujitsu.com> In-Reply-To: <4D6DBDA4.3050909@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-03-02 11:58:37, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-03-02 11:58:38, Serialize complete at 2011-03-02 11:58:38 X-detected-operating-system: by eggs.gnu.org: FreeBSD 6.x (1) X-Received-From: 222.73.24.84 Cc: Subject: [Qemu-devel] [PATCH RESEND 2/2] vnc: Fix heap corruption X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This bug is reported by Stefan Weil: Acked-by: Corentin Chary ======== Commit bc2429b9174ac2d3c56b7fd35884b0d89ec7fb02 introduced a severe bug (heap corruption). bitmap_clear was called with a wrong argument which caused out-of-bound writes to width_mask. This bug was detected with QEMU running on windows. It also occurs with wine: *** stack smashing detected ***: terminated wine: Unhandled illegal instruction at address 0x6115c7 (thread 0009), starting debugger... The bug is not windows specific! ======== The third argument of bitmap_clear() is number of bits to be cleared, but we pass the end bits to be cleared to bitmap_clear(). Signed-off-by: Wen Congyang Reported-by: Stefan Weil --- ui/vnc.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/ui/vnc.c b/ui/vnc.c index e3761b0..e7d0b5b 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -2390,6 +2390,7 @@ static int vnc_refresh_server_surface(VncDisplay *vd) unsigned long width_mask[VNC_DIRTY_WORDS]; VncState *vs; int has_dirty = 0; + const size_t width = ds_get_width(vd->ds) / 16; struct timeval tv = { 0, 0 }; @@ -2403,9 +2404,8 @@ static int vnc_refresh_server_surface(VncDisplay *vd) * Check and copy modified bits from guest to server surface. * Update server dirty map. */ - bitmap_set(width_mask, 0, (ds_get_width(vd->ds) / 16)); - bitmap_clear(width_mask, (ds_get_width(vd->ds) / 16), - VNC_DIRTY_WORDS * BITS_PER_LONG); + bitmap_set(width_mask, 0, width); + bitmap_clear(width_mask, width, VNC_DIRTY_WORDS * BITS_PER_LONG - width); cmp_bytes = 16 * ds_get_bytes_per_pixel(vd->ds); guest_row = vd->guest.ds->data; server_row = vd->server->data;