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SubjectRe: [PATCH] virtio_console: Assure used length from device is limited
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在 2021/5/25 下午12:53, Xie Yongji 写道:
> 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.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>


Acked-by: Jason Wang <jasowang@redhat.com>


> ---
> drivers/char/virtio_console.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> index 1c40ca6d76ba..598863e6daf8 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -475,7 +475,7 @@ 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(len, buf->size);
> buf->offset = 0;
> port->stats.bytes_received += len;
> }
> @@ -1709,7 +1709,7 @@ 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(len, buf->size);
> buf->offset = 0;
>
> handle_control_message(vq->vdev, portdev, buf);

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