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

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>

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index e221aba9e3a5031e64e84c12c43d7c8ed72caae1..f0fa42f9374c6f5b799b550db871d96a798ca5df 100644 (file)
--- 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,