From patchwork Tue Oct 11 16:27:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 680815 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org 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 3stj9c2c8vz9s9N for ; Wed, 12 Oct 2016 03:28:52 +1100 (AEDT) Received: from localhost ([::1]:56907 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btzv6-00029s-Tk for incoming@patchwork.ozlabs.org; Tue, 11 Oct 2016 12:28:48 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51911) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btzuC-0001Y8-G6 for qemu-devel@nongnu.org; Tue, 11 Oct 2016 12:27:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1btzu7-0005EW-DG for qemu-devel@nongnu.org; Tue, 11 Oct 2016 12:27:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44616) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btzu7-0005EB-6w for qemu-devel@nongnu.org; Tue, 11 Oct 2016 12:27:47 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (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 270524E03F; Tue, 11 Oct 2016 16:27:46 +0000 (UTC) Received: from javelin.localdomain (vpn1-7-178.sin2.redhat.com [10.67.7.178]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u9BGRf9R010726 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 11 Oct 2016 12:27:43 -0400 From: P J P To: Qemu Developers Date: Tue, 11 Oct 2016 21:57:40 +0530 Message-Id: <1476203260-5290-1-git-send-email-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 11 Oct 2016 16:27:46 +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] 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/char/serial.c b/hw/char/serial.c index 3442f47..f659bbd 100644 --- a/hw/char/serial.c +++ b/hw/char/serial.c @@ -153,7 +153,7 @@ 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. */