bsg: Check queue type before attaching to a queue

Since BSG only supports request queues for which struct scsi_request
is the first member of their private request data, refuse to register
block layer queues for which struct scsi_request is not the first
member of their private data.

References: commit bd1599d9 ("scsi_transport_sas: fix BSG ioctl memory corruption")
References: commit 82ed4db4 ("block: split scsi_request out of struct request")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/bsg.c

@@ -750,6 +750,12 @@ static struct bsg_device *bsg_add_device(struct inode *inode,
 #ifdef BSG_DEBUG
 	unsigned char buf[32];
 #endif
+
+	if (!blk_queue_scsi_passthrough(rq)) {
+		WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	if (!blk_get_queue(rq))
 		return ERR_PTR(-ENXIO);