qemu/0017-char-serial-check-divi...

35 lines
1.2 KiB
Diff

From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Wed, 12 Oct 2016 11:28:08 +0530
Subject: [PATCH] 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 <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>
(cherry picked from commit 3592fe0c919cf27a81d8e9f9b4f269553418bb01)
---
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 3442f47d36..eec72b7b9e 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;