From: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
Date: Thu, 17 Dec 2020 21:33:21 +0100
Patch-mainline: v5.12-rc1
Subject: scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()
Git-commit: 91b1b640b834b2d6f330baf04c0cc049eca9d689
References: bsc#1204017

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

Link: https://lore.kernel.org/r/20201217203321.4539-4-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
Reported-by: Saruhan Karademir <skarade@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/scsi/storvsc_drv.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1265,6 +1265,12 @@ 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) -
+				stor_device->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,