@@ -580,11 +580,12 @@ static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
struct virtio_console_config *config =
(struct virtio_console_config *)config_data;
- uint8_t emerg_wr_lo = le32_to_cpu(config->emerg_wr);
VirtIOSerialPort *port = find_first_connected_console(vser);
VirtIOSerialPortClass *vsc;
+ uint8_t emerg_wr_lo;
- if (!config->emerg_wr) {
+ if (!virtio_has_feature(vser->host_features,
+ VIRTIO_CONSOLE_F_EMERG_WRITE) || !config->emerg_wr) {
return;
}
/* Make sure we don't misdetect an emergency write when the guest
@@ -594,6 +595,7 @@ static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
return;
}
vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
+ emerg_wr_lo = le32_to_cpu(config->emerg_wr);
(void)vsc->have_data(port, &emerg_wr_lo, 1);
}
Check device having the feature of VIRTIO_CONSOLE_F_EMERG_WRITE before get config->emerg_wr. It is neccessary because sizeof(virtio_console_config) is 8 byte if VirtIOSerial doesn't have the feature of VIRTIO_CONSOLE_F_EMERG_WRITE(see virtio_serial_device_realize), read/write emerg_wr will lead to heap-over-flow. Signed-off-by: linzhecheng <linzhecheng@huawei.com>