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 <linzhech...@huawei.com>
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index 9470bd7be7..d2dd8ab502 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -580,13 +580,16 @@ 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;
}
+
+ emerg_wr_lo = le32_to_cpu(config->emerg_wr);
/* Make sure we don't misdetect an emergency write when the guest
* does a short config write after an emergency write. */
config->emerg_wr = 0;
--
2.12.2.windows.2
