This is a note to let you know that I've just added the patch titled
virtio_console: Assure used length from device is limited
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
virtio_console-assure-used-length-from-device-is-lim.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 640737266e80003bcea7ca2c0895fe889cdd8a1f
Author: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
Date: Tue May 25 20:56:22 2021 +0800
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@xxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210525125622.1203-1-xieyongji@xxxxxxxxxxxxx
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 5eabbf73fdef..b453029487a1 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_t(size_t, len, buf->size);
buf->offset = 0;
port->stats.bytes_received += len;
}
@@ -1714,7 +1714,7 @@ 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);
