Commit 9e2b8368 authored May 25, 2021 by Xie Yongji Committed by Greg Kroah-Hartman Jul 20, 2021

virtio_console: Assure used length from device is limited



[ 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.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210525125622.1203-1-xieyongji@bytedance.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 102d6bc6

drivers/char/virtio_console.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -492,7 +492,7 @@ 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;
		}
		@@ -1758,7 +1758,7 @@ 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);