-----Original Message-----
From: Andres Beltran <redacted>
Sent: Thursday, June 25, 2020 11:37 AM
To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
[off-list ref]; Stephen Hemminger [off-list ref];
wei.liu@kernel.org
Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; Michael
Kelley [off-list ref]; parri.andrea@gmail.com; Andres Beltran
[off-list ref]; David S. Miller [off-list ref]; Jakub
Kicinski [off-list ref]; netdev@vger.kernel.org
Subject: [PATCH 3/3] hv_netvsc: Use vmbus_requestor to generate transaction
IDs for VMBus hardening

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.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Andres Beltran <redacted>
---
 drivers/net/hyperv/hyperv_net.h   | 10 +++++
 drivers/net/hyperv/netvsc.c       | 75 +++++++++++++++++++++++++------
 drivers/net/hyperv/rndis_filter.c |  1 +
 include/linux/hyperv.h            |  1 +
 4 files changed, 73 insertions(+), 14 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index abda736e7c7d..14735c98e798 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h

@@ -847,6 +847,16 @@ struct nvsp_message {

 #define NETVSC_XDP_HDRM 256

+#define NETVSC_MIN_OUT_MSG_SIZE (sizeof(struct vmpacket_descriptor) + \
+				 sizeof(struct nvsp_message))
+#define NETVSC_MIN_IN_MSG_SIZE sizeof(struct vmpacket_descriptor)
+
+/* Estimated requestor size:
+ * out_ring_size/min_out_msg_size + in_ring_size/min_in_msg_size
+ */
+#define NETVSC_RQSTOR_SIZE (netvsc_ring_bytes /

NETVSC_MIN_OUT_MSG_SIZE + \
+			    netvsc_ring_bytes / NETVSC_MIN_IN_MSG_SIZE)