For additional robustness in the face of Hyper-V errors or malicious
behavior, validate all values that originate from packets that Hyper-V
has sent to the guest in the host-to-guest ring buffer.  Ensure that
invalid values cannot cause data being copied out of the bounds of the
source buffer in hvs_stream_dequeue().
Signed-off-by: NAndrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: NMichael Kelley <mikelley@microsoft.com>
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20220428145107.7878-4-parri.andrea@gmail.comSigned-off-by: NWei Liu <wei.liu@kernel.org>