From mboxrd@z Thu Jan 1 00:00:00 1970 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 From: P J P Date: Wed, 12 Oct 2016 11:28:08 +0530 Message-Id: <1476251888-20238-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v2] char: serial: check divider value against baud base List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: "Michael S. Tsirkin" , Paolo Bonzini , Huawei PSIRT , Prasad J Pandit 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; -- 2.5.5