Hi!
> From: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
>
> [ Upstream commit d00d8da5869a2608e97cfede094dfc5e11462a46 ]
>
> The buf->len might come from an untrusted device. This
> ensures the value would not exceed the size of the buffer
> to avoid data corruption or loss.
Since we are not trusting the other side, do we need to use _nospec
variants to prevent speculation attacks?
Best regards,
Pavel
> +++ b/drivers/char/virtio_console.c
> @@ -487,7 +487,7 @@ static struct port_buffer *get_inbuf(struct port *port)
>
> buf = virtqueue_get_buf(port->in_vq, &len);
> if (buf) {
> - buf->len = len;
> + buf->len = min_t(size_t, len, buf->size);
> buf->offset = 0;
> port->stats.bytes_received += len;
> }
> @@ -1752,7 +1752,7 @@ static void control_work_handler(struct work_struct *work)
> while ((buf = virtqueue_get_buf(vq, &len))) {
> spin_unlock(&portdev->c_ivq_lock);
>
> - buf->len = len;
> + buf->len = min_t(size_t, len, buf->size);
> buf->offset = 0;
>
> handle_control_message(vq->vdev, portdev, buf);
--
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