From patchwork Wed Oct 12 05:58:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 9372099 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4CAA260839 for ; Wed, 12 Oct 2016 05:58:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 31CA329A9A for ; Wed, 12 Oct 2016 05:58:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 25DCE29AAC; Wed, 12 Oct 2016 05:58:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7E82129A9A for ; Wed, 12 Oct 2016 05:58:38 +0000 (UTC) Received: from localhost ([::1]:59422 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buCYl-0006nk-T3 for patchwork-qemu-devel@patchwork.kernel.org; Wed, 12 Oct 2016 01:58:35 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53390) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buCYX-0006ne-Qv for qemu-devel@nongnu.org; Wed, 12 Oct 2016 01:58:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1buCYS-0007Nv-TF for qemu-devel@nongnu.org; Wed, 12 Oct 2016 01:58:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54094) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buCYS-0007MW-NG for qemu-devel@nongnu.org; Wed, 12 Oct 2016 01:58:16 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DB5153B70B; Wed, 12 Oct 2016 05:58:14 +0000 (UTC) Received: from javelin.localdomain (vpn1-4-11.sin2.redhat.com [10.67.4.11]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u9C5w9B4004574 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 12 Oct 2016 01:58:12 -0400 From: P J P To: Qemu Developers Date: Wed, 12 Oct 2016 11:28:08 +0530 Message-Id: <1476251888-20238-1-git-send-email-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 12 Oct 2016 05:58:15 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2] char: serial: check divider value against baud base 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: Paolo Bonzini , Huawei PSIRT , Prasad J Pandit , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Prasad J Pandit 16550A UART device uses an oscillator to generate frequencies (baud base), which decide communication speed. This speed could be changed by dividing it by a divider. If the divider is greater than the baud base, speed is set to zero, leading to a divide by zero error. Add check to avoid it. Reported-by: Huawei PSIRT Signed-off-by: Prasad J Pandit --- hw/char/serial.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Update per -> https://lists.gnu.org/archive/html/qemu-devel/2016-10/msg02400.html diff --git a/hw/char/serial.c b/hw/char/serial.c index 3442f47..eec72b7 100644 --- a/hw/char/serial.c +++ b/hw/char/serial.c @@ -153,8 +153,9 @@ static void serial_update_parameters(SerialState *s) int speed, parity, data_bits, stop_bits, frame_size; QEMUSerialSetParams ssp; - if (s->divider == 0) + if (s->divider == 0 || s->divider > s->baudbase) { return; + } /* Start bit. */ frame_size = 1;