hv_netvsc: Check status in SEND_RNDIS_PKT completion message

Completion responses to SEND_RNDIS_PKT messages are currently processed
regardless of the status in the response, so that resources associated
with the request are freed.  While this is appropriate, code bugs that
cause sending a malformed message, or errors on the Hyper-V host, go
undetected. Fix this by checking the status and outputting a rate-limited
message if there is an error.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Link: https://lore.kernel.org/r/1676264881-48928-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 79f4e13620a4607e3779769334160f383a4a5767..da737d959e81c034a97c6fa99ffcb565d6aeb67e 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -851,6 +851,7 @@ static void netvsc_send_completion(struct net_device *ndev,
        u32 msglen = hv_pkt_datalen(desc);
        struct nvsp_message *pkt_rqst;
        u64 cmd_rqst;
+       u32 status;
 
        /* First check if this is a VMBUS completion without data payload */
        if (!msglen) {
@@ -922,6 +923,23 @@ static void netvsc_send_completion(struct net_device *ndev,
                break;
 
        case NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE:
+               if (msglen < sizeof(struct nvsp_message_header) +
+                   sizeof(struct nvsp_1_message_send_rndis_packet_complete)) {
+                       if (net_ratelimit())
+                               netdev_err(ndev, "nvsp_rndis_pkt_complete length too small: %u\n",
+                                          msglen);
+                       return;
+               }
+
+               /* If status indicates an error, output a message so we know
+                * there's a problem. But process the completion anyway so the
+                * resources are released.
+                */
+               status = nvsp_packet->msg.v1_msg.send_rndis_pkt_complete.status;
+               if (status != NVSP_STAT_SUCCESS && net_ratelimit())
+                       netdev_err(ndev, "nvsp_rndis_pkt_complete error status: %x\n",
+                                  status);
+
                netvsc_send_tx_complete(ndev, net_device, incoming_channel,
                                        desc, budget);
                break;