RE: [PATCH v7 3/3] hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening

From: Michael Kelley
Date: Mon Sep 07 2020 - 18:02:54 EST


From: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Sent: Monday, September 7, 2020 9:19 AM
>
> From: Andres Beltran <lkmlabelt@xxxxxxxxx>
>
> Currently, pointers to guest memory are passed to Hyper-V as
> transaction IDs in netvsc. In the face of errors or malicious
> behavior in Hyper-V, netvsc should not expose or trust the transaction
> IDs returned by Hyper-V to be valid guest memory addresses. Instead,
> use small integers generated by vmbus_requestor as requests
> (transaction) IDs.
>
> Signed-off-by: Andres Beltran <lkmlabelt@xxxxxxxxx>
> Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> ---
> Changes in v7:
> - Move the allocation of the request ID after the data has been
> copied into the ring buffer (cf. 1/3).
> Changes in v2:
> - Add casts to unsigned long to fix warnings on 32bit.
> - Use an inline function to get the requestor size.
>
> drivers/net/hyperv/hyperv_net.h | 13 +++++++++++++
> drivers/net/hyperv/netvsc.c | 22 ++++++++++++++++------
> drivers/net/hyperv/rndis_filter.c | 1 +
> include/linux/hyperv.h | 1 +
> 4 files changed, 31 insertions(+), 6 deletions(-)
>

Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>