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char: serial: check divider value against baud base

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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 <psirt@huawei.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <1476251888-20238-1-git-send-email-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Prasad J Pandit 2016-10-12 11:28:08 +05:30 committed by Paolo Bonzini
parent 0a752eeea8
commit 3592fe0c91
1 changed files with 2 additions and 1 deletions
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3
hw/char/serial.c
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@ -153,8 +153,9 @@ static void serial_update_parameters(SerialState *s)
int speed, parity, data_bits, stop_bits, frame_size; int speed, parity, data_bits, stop_bits, frame_size;
QEMUSerialSetParams ssp; QEMUSerialSetParams ssp;
if (s->divider == 0) if (s->divider == 0 || s->divider > s->baudbase) {
return; return;
}
/* Start bit. */ /* Start bit. */
frame_size = 1; frame_size = 1;