From 7e0ebfd13e55a706396197437f375692bbf75d15 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Wed, 12 Oct 2016 11:28:08 +0530 Subject: [PATCH 2/2] char: serial: check divider value against baud base 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(-) 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; -- 2.1.4