[PATCH] scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()

["Andrea Parri (Microsoft)" <parri.andrea@gmail.com>]

Check that the packet is of the expected size at least, don't copy
data past the packet.

Reported-by: Saruhan Karademir <skarade@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
---
Based on hyperv-next.

 drivers/scsi/storvsc_drv.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 331a33a04f1ad..629a46a0bab6e 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1270,6 +1270,11 @@ static void storvsc_on_channel_callback(void *context)
 
 		request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst;
 
+		if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) - vmscsi_size_delta) {
+			dev_err(&device->device, "Invalid packet len\n");
+			continue;
+		}
+
 		if (request == &stor_device->init_request ||
 		    request == &stor_device->reset_request) {
 			memcpy(&request->vstor_packet, packet,
-- 
2.25.1